Refinery Terminology

by Adhi Budhiarto

Some of Refinery Terminology are as follows:

Absorption

Hydrocarbon liquid or gas refining process to remove impurities by dissolving the impurities into an absorbent (usually liquid) so that the impurities are absorbed in the absorbent.

ADO (Automotive Diesel Oil)

Refinery product which is the result of diesel and gas oil blending.  It is simply called as diesel oil.

Adsorption

Hydrocarbon liquid or gas refining process to remove impurities by adsorbing the impurities into an adsorbent (usually solid, such as activated carbon or catalyst).

Air Cooler/ Fin Fan Cooler

Heat exchanger which is used to chill or to condense fluid by using air as cooling medium.  Air is blew by a blower.  Tubes of air cooler are equipped with fins in order to increase surface area of heat transfer.

Air Pre-heater

Part of fired heater/furnace which is used to heat up combustion air by utilizing the furnace flue gas as heating medium.

Amine Regeneration Unit (ARU)

Refinery processing unit which is designed to recover amine solution from rich amine solution usually coming from Vacuum Gas Oil Hydro Treating Unit (VGO-HDT), Fluid Catalytic Cracking Unsaturated Gas Plant, or Sour Water  Stripping Unit.  Amine solution is used in those processing units to remove sulphur compound.  Recovered amine, usually called as lean amine, is routed back to those processing units.  If the amine concentration is less than its minimum limitation, make up of amine solution is done.  Some amine solutions which are often used in refinery are Mono Ethanol Amine (MEA), Diglycol Amine (DGA), Diethanolamine (DEA), Diisopropanol Amine (DIPA), Triethanol Amine (TEA), and Methyl Diethanol Amine (MDEA).

Amine Unit

See Amine Regeneration Unit definition.

API Gravity

API stands for American Petroleum Institute.  API Gravity is a definition for gravity of hydrocarbon liquid defined by American Petroleum Institute.  API Gravity = (141.5/SG – 131.5).  SG is Specific Gravity.

Aromatic Extraction

Extraction process to produce BTX (Benzene, Toluene, Xylene) or to reduce aromatic content of kerosene and jet fuel.  Dimethyl formanide (DMF), N-formyl morpholine (NF), Dimethylsulfoxide (DMSO), Sulfolane, and Ethylene Glicol are used as solvent.

ARU

See Amine Regeneration Unit definition.

Atmospheric Residue/Long Residue

Bottom product of Crude Distillation Unit (CDU).  This product has very low economic value so that it should be processed to get higher economic value.

Atomizing Steam

Steam which is used to atomize fuel oil to fired heater/furnace through burner to result in good combustion and goon flame pattern.

Automotive Diesel Oil

See ADO definition.

Avgas

It stands for Aviation Gasoline.  Avgas is typically used in aircraft that use reciprocating or wankel engines.  It is also used as fuel for racing cars.

Avtur

It stands for Aviation Turbine fuel.  It is also commonly called as aviation kerosene, jet fuel, Jet A-1, or ATK (Aviation Turbine Kerosene).  It is used as fuel for aircraft or turbine engines or compression ignition engines.

Axens

French company which is an international provider of technologies (process licenses), products (catalysts and adsorbents) and services (technical assistance, training, consulting) to the refining, petrochemical, gas and alternative fuels markets.

Backwash

Process to clean or remove impurities in the filter by inverting fluid flow so that impurities can be removed from the filter.  Backwash is usually done when filter pressure drop nearly reaches its maximum limit.

Barrel Standard Refinery Fuel

Unit of measurement which is used to measure fuel consumption of a heater or a refinery processing unit.  BSRF = TSRF x 6.531.  See TSRF definition.

Battery Limit

Area in the plant boundary which is a boundary between one processing unit to the other processing unit.  In this area, feed to the plant or product from the plant is connected from upstream process or.to downstream process/storage.

Bearing

Part of rotating equipment which is used to maintain shaft/rotor to rotate at its axis and to avoid any slope caused by rotation load and radial/axial force.

Bed Temperature

Temperature which is measured at catalyst bed of a reactor.

Benfield Process

Gas treating to remove acid compound by using Potassium Carbonate (K2CO3) and activating agent DEA (Diethanol Amine).  Benfield solution is comprised of K2CO3 (25-27 wt%), KVO3/V2O5 (0.7-0.8 wt%), and DEA as activating agent (3 wt%).  The reactions are as follows:

CO2 + R2NH            <——->    R2NCOOH

R2NCOOH + KOH  <——->    R2NH +  KHCO3

BFW (Boiler Feed Water)

Water to be fed to Boiler.  Before being fed to Boiler, the water is previously processed in demineralization plant for external treatment (to remove anion-kation) and for internal treatment (by chemical like hydrazin, phosphate, and amine).

BHP (Brake Horse Power)

Power results from motor to rotate pump or compressor shaft.

BL

See Battery Limit definition.

Blackout

Condition in the refinery which is all utility, such as electricity, steam, and instrument air were tripped altogether so that all refinery plants are emergency shutdown.

Block Valve

Valve which is used to isolate an equipment or a control valve.  It is installed in the upstream and/or in the downstream of the equipment.

Blowdown

Drain of a vessel or steam generator or boiler to maintain level or pressure or to discharge impurities from the system.  In the steam regenerator or boiler there are 2 kinds of blowdown, continuous blowdown and intermittent blowdown.  Continuous blowdown is usually around 5 vol% of feed to maintain boiler water quality, whereas intermittent blowdonw was done intermittently based on its necessity.

Blower

A device to route air or gas.  A blower is usually used to route combution air in a fired heater/furnace or to route air as a cooling media in an air cooler.

Boiler

Equipment which is similar to fired heater/furnace having tubes insides to produce steam.

Boiler Feed Water

See BFW definition.

Brake Horse Power

See BHP definition.

Bromine Number

The amount of bromine in grams absorbed by 100 grams of a sample. The number indicates the degree of unsaturation.  The Bromine Number is useful as a measure of aliphatic unsaturation in gasoline samples.  The data showed that the Bromine Number of gasoline is about 2.4 times the olefin content.  A gasoline with Bromine Number of 30 would then have an olefin content of about 12.5 percent by volume.

Burner

Equipment which is a part of fired heater/furnace or boiler where fuel oil or fuel gas is burnt to get fire/flame to heat up fluid inside tube.

Calcined Coke

One of Delayed Coking Unit (DCU) products which can be further processed to be anode.  Calcined Coke is processed from Green Coke whose quality is increased by processing it in a calciner to remove water content (reduce moisture content), reduce volatile matter, and increase Vibrated Bulk Density (VBD).

Carbonate Process

Gas treating process to remove acid compounds by using Potassium Carbonate (K2CO3).  The reactions are as follows:

K2CO3 + CO2 + H2O   <——>    2KHCO3

K2CO3 + H2S    <——>    KHS  +  KHCO3

COS + H2O     <——>    CO2  +  H2S

Catalyst

A substance which accelerates reaction in a reactor.  Catalyst is used in a conversion refinery plant which has specific process.  Catalyst types are varied such as sphere, 3-lobe, 4-lobe, fluted ring, cylinder, and ring.

Catalyst Regeneration

Process to renew catalyst performance by burning carbon which is adsorbed in the catalyst surface.  There are 2 regeneration process types, in-situ regeneration and ex-situ regeneration.  In-situ regeration is regeneration process which is done at site without unloading the catalyst, whereas ex-situ regeneration is regeneration process which is done outside by unloading the catalyst first (it is usually done by other company speciallizing in catalyst regeneration).  For small refinery plant, like hydrobon or small hydrotreating unit, or for fixed bed catalytic reforming unit, regeneration process is usually done by in-situ regeneration, whereas for big refinery plant, like Hydrocracker Unibon, regeneration process is usually done by ex-situ regeneration (it depends on economical evaluation).

Catalyst Sulfiding

Process to activate new catalyst which is usually bought from catalyst vendor in inactive form (oxide form).  In the catalyst sulfiding, catalyst is reduced from oxide form to sulfide form.

Catalyst Unloading

An activity to unload catalyst from a reactor.  Used/spent catalyst that is already not performed well is unloaded from a reactor to be replaced by new or regenerated catalyst.

Catalyst Loading

An activity to load catalyst to a reactor.  After unloading process, a reactor is cleaned and new or regenerated catalyst is loaded to the reactor.

Catalytic Cracking

Cracking process of hydrocarbon liquid with the use of catalyst.  Examples of catalytic cracking are Hydrocracker Unibon (HCU), Fluid Catalytic Cracking (FCC), Residual Catalytic Cracking (RCC), Residual Fluid Catalytic Cracking (RFCC), and High Olefine Fluid Catalytic Cracking (HOFCC).  The difference among FCC, RCC, RFCC, and HOFCC is mainly in the feed properties.

Catalytic Reforming/Platforming

Refinery processing unit which processes heavy naphtha from Naphtha Hydro Treating Unit (NHDT) to be converted to LPG (Liquid Petroleum Gas) and reformate (or commonly called as High Octane Motor Gasoline Component/HOMC) by using specific catalyst.  In the early generation, it comprised of fixed bed reactors (usually 1 reactor for feed preparation, usually called as hydrobon reactor, and 3 reactors for Catalytic Reforming process) with catalyst regeneration every 1 or 2 years and with complete change out of catalyst usually after around 7 times of catalyst regeneration.  Catalyst regeneration is usually conducted at site (in-situ regeneration).  Nowadays, Catalytic Reforming/Platforming is designed with Continuous Catalytic Regeneration (CCR).  It comprises of fluidized reactors (usually 3 reactors) and 1 regenerator for Continuous Catalytic Regeneration.  “Platforming” is Catalytic Reforming unit trade mark of UOP (Universal Oil Product).

Caustic Wash

It is common washing process in refinery to remove impurities by using caustic (NaOH).  It can be used to remove impurities, such as mercaptan, H2S & CO2, phenol, fatty acid, naphthenic acid, HCl & HCN, and COS.  Usually caustic concentration is from 5 to 15%.  There are 2 kinds of Caustic Wash in refinery, Merox Process and Solutizer Process.

Cavitation

The formation of vapor bubbles of a flowing liquid in a region where the pressure of the liquid falls below its vapor pressure.  Cavitation is usually divided into two classes of behavior: inertial (or transient) cavitation, and non-inertial cavitation.  Inertial cavitation is the process where a void or bubble in a liquid rapidly collapses, producing a shock wave. Such cavitation often occurs in control valves, pumps, propellers, impellers, and in the vascular tissues of plants. Noninertial cavitation is the process in which a bubble in a fluid is forced to oscillate in size or shape due to some form of energy input, such as an acoustic field. Such cavitation is often employed in ultrasonic cleaning baths and can also be observed in pumps, propellers, etc.

CCR (Continuous Catalytic Regeneration)

See Catalytic Reforming/Platforming definition.

CCR (Conradson Carbon Residue) Test

A destructive-distillation method for estimating carbon residues in fuels and lubricating oils.  Carbon residue is the quantity of carbon produced from a lubricating oil heated in a closed container under standard conditions.

CDU (Crude Distillation Unit)/Topping Unit

Refinery plant that processes crude oil to be lighter product by distillation process (based on its each fraction boiling point).  CDU produces Liquid Petroleum Gas (LPG), naphtha, kerosene, Light Gas Oil (LGO), Heavy Gas Oil (HGO), and atmospheric residue.

Centrifugal Compressor

Compressors using a rotating disk or impeller in a shaped housing to force the gas to the rim of the impeller, increasing the velocity of the gas.

CFR (Combined Feed Ratio)

Ratio between total fresh feed and recycle feed volumetric flows to fresh feed flow (for Hydrocracker Unibon) or ratio between total fired heater volumetric flow to fresh feed volumetric flow (for Delayed Coking Unit).

Change Out of Catalyst (COC)

An activity of unloading and loading of catalyst.  Please refer to Catalyst Unloading and Catalyst Loading terminologies.  Catalyst change out is usually done every 1 to 5 years depending on catalyst performance and economical evaluation.

Charge Heater

Fired Heater/Furnace which is used to increase temperature of refinery processing unit feed/charge.

Check Valve

Valve which is used to avoid back flow in the piping system.

Claus Reaction

Reaction to produce elemental sulphur.  It is the most important Sulphur Recovery Unit (SRU) reaction.  The reaction is as follows:

2 H2S + SO2     <——->     3/x Sx + 2 H2O + Heat

Clay Treating

Treating process to upgrade color of hydrocarbon fractions, such as lube oil.  There are 3 types of Clay Treating, Percolation (coarse clay), Contact in high temperature (powder clay), and contact at vapor phase (packed clay).

COC

See Change Out of Catalyst definition.

Coke Calcining Unit

Refinery processsing unit which is used to convert green coke to be calcined coke to reduce water content (moisture content), to reduce volatile matter, and to increase Vibrated Bulk Density (VBD) by processing it in a calciner in Delayed Coking Unit (DCU).

Coke Chamber

Vessel or chamber where thermal cracking of heavy oil takes place to be converted to coke (this cracking process is comonly called as coking process).  Coke chamber exists in a Delayed Coking Unit.

Column/ Distillation Column/Fractionation Column

Vessel that is used for distillation or fractionation process to separate hydrocarbon fractions based on its each fraction boiling point.

Combined Feed Ratio

See CFR definition.

Compressor

A mechanical device that increases the pressure of a gas by reducing its volume.  There are 2 types of compressors that are commonly used in a refinery, centrifugal compressor and reciprocating compressor.

Condensate

The liquid hydrocarbon resulting from cooling vapors or water resulting from steam condensation after being used for turbine generator or heating media.  The last term is usually called steam condensate.

Conradson Carbon Residue (CCR) Test

See CCR (Conradson Carbon Residue) Test definition.

Control Room

A place where console operators monitor and control operating condition by using Distributed Control System (DCS).

Control Valve

A valve which is used to control operating condition in a refinery plant.  It is used to control flow (Flow Control Valve/FCV), temperature (Temperature Control Valve/TCV), and pressure (Pressure Control Valve/PCV).  Control valve is usually controlled from control room by using Distributed Control System (DCS).

Convection Section

A part of fired heater/furnace where cold fluid is initially heated up or where steam is produced.  The heating media in the convection section is the flue gas of the fired heater/furnace.

Cooling Down

An activity to reduce temperature of reactor or fired heater/furnace or refinery plant system gradually based on plant shutdown procedure.  Temperature reduction rate must not too fast that can damage refractory or catalyst or equipment.  Safe temperature reduction rate is 40 degC/hour.

Cooling Water

Fresh water which is used as cooling media in heat exchangers.

Cracking

A process to crack or break of chemical bond of hydrocarbon liquid to produce higher value products.  Generally, there are 2 types of cracking process, catalytic cracking and thermal cracking.  Term “cracking” is also used for unexpected cracking process of crude oil in Crude Distillation Unit.  Commonly, if crude oil is heated up to more than 370 degC at atmospheric pressure, the crude oil experiences cracking process.

Crude Distillation Unit

See CDU definition.

Crude Oil

Hydrocarbon compound which comes from a conversion of animal (plankton) fossil millions of years ago.  Crude oil has different physical properties and specification depending on the place that it is collected.  Based on its chemical bond, crude oil is commonly classified as 4 types, which are Parafinic, Olefinic, Naphthenic, and Aromatic.

Damper

A device that damps as a valve or plate in a fired heater/furnace.  It is a part of fired heater/furnace to adjust combution air rate (in the burner side) or to regulate the draft (in the flue gas stack side).

DCS (Distributed Control System)

A process control system to monitor field operating condition in a console.  It is operated by console operator/panelman.

DCU (Delayed Coking Unit)

Refinery processing unit that processes short residue/vacuum residue of Vacuum Distillation Unit (VDU) based on thermal cracking principle to produce LPG, naphtha, Light Coker Gas Oil (LCGO), Heavy Coker Gas Oil (HCGO), and green coke or calcined coke.

Debutanizer

Fractionation column which is used to remove butane and lighter hydrocarbon fraction.  Butane and lighter hydrocarbon fraction is then routed to LPG Plant to produce LPG.

Delayed Coking Unit

See DCU definition.

Depressure

An action to reduce pressure of a refinery processing unit system.  It is usually done during emergency condition or unit shutdown.  It is usually done in a refinery processing unit that has high or medium pressure process and that involves reaction, like in Hydrocracker Unibon or Hydro Treating Unit.  Depressure is done to reduce reaction so that temperature excursion or temperature runaway can be avoided.

Desalter

Liquid Treating to remove salts contained in hydrocarbon fraction (usually crude oil).  Common salts contained in crude oil are chloride & sulphide salts (sodium, magnesium, and calcium), and nickel & vanadium salts.

Desuperheater

A device that is used to reduce temperature of steam product to produce saturated steam.

DHDT (Distillate Hydrotreating Unit)

A refinery processing unit that processes Light Coker Gas Oil (LCGO) from Delayed Coking Unit (DCU) to be Light Kerosene and Heavy Kerosene.  In this unit, impurities is removed by hydrotreating process.  Reactor effluent is separated to be Light Kerosene and Heavy Kerosene in a Stripper-Splitter column.

Discharge

A part of a pump or a compressor where fluid is routed out after being pressed up by impeller or piston.

Displacer

A device to measure liquid height in a vessel.  The measurement reading is sent to control room so that it can be monitored and controled in Distributed Control System (DCS).

Distillate Hydrotreating Unit

See DHDT definition.

Distillation/Fractionation

A process to separate hydrocarbon fractions based on its each fraction boiling point.  It is usually equipped with reboiler (or stripping steam), overhead condenser, and side streppers to get good quality products.

Distillation Column

See Column definition.

Distributed Control System

See DCS definition.

Distributor

A device that is used to distribute fluid flow entering to a vessel so that flow distribution is uniform.

Doctor Treatment

Washing process to upgrade gasoline quality.  In this process, mercaptan is converted into disulphide compound by active substance sodium plumbit; elemental sulphur is then added to complete the process.  The reactions are as follows:

2 RHS  + Na2PbO2  —> (RS)2Pb + 2NaOH

(RS)2Pb + S —-> R2S2 + PbS

Drain

A pipe that is used to drain or empty a system (piping, pump, or vessel) from liquid.  A drain pipe is usually located at low point, opposed to Venting.  See Venting definition.

Draw off/Side Draw

Hydrocarbon liquid which is taken out or pumped out from distillation column to be taken as a product or to be returned back to distillation column (after being cooled down) as a pumparound to control drawoff temperature to get appropriate product.

Dry out

A heating process in a fired heater/furnace to remove water contained in refractory or castable to dry it out.  Dry out process is done gradually.  An example of dry out process is as follows: fired heater/furnace is heated up to 100-110 oC at a rate of 20 oC/hour, hold it for 8 hours, then it is further heated up to 220 oC at a rate of 20 oC/hour, hold it for 10 hours, then it is furter heated up at a rate of 40 oC/hour to a certain operating temperature (for example 1250 oC for a Reaction Furnace), hold it for 15 hours, then cooling down at a rate of 30 oC/hour until fired heater/furnace temperature is 40 oC, then fired heater/furnace is open to inspect the result of the dry out process.

Edeleanu Process

Extraction process to remove impurities by using SO2.  Aromatic compounds and unsaturated hydrocarbon dissolve perfectly in liquid SO2, while paraffin and naphtha do not dissolve in liquid SO2.  Therefore, they can be extracted.  Edeleanu Process can also be used for kerosene desulphurization and for kerosene smoke point quality upgrade.

EIV (Emergency Isolation Valve)

A valve which is used to isolate a system in an emergency situation.  Recently, EIV is also connected to Safety Instrumentation System (SIS) to provide safer operation of a refinery processing unit.  In the SIS, some EIVs can be included in a sequence so that they can be energized by clicking the sequence in DCS.

Emergency Isolation Valve

See EIV (Emergency Isolation Valve) definition.

Emergency Shutdown Device (ESD)

An instrumentation device which is used to shutdown or to trip an equipment (such as pump, compressor, fired heater/furnace, control valve, or Emergency Isolation Valve (EIV)) or to trip a refinery processing unit if a certain operating condition is achieved to avoid dangerous impact to the equipment or the unit.

End Point (EP)

The highest temperature when a specified portion of hydrocarbon liquid is completely boiled off.  It is also commonly called Final Boiling Point (FBP).

ETC (Estimated Time Completion)

Estimated time that an activity is planned to be completed.

ESD

See Emergency Shutdown Device (ESD) definition.

Estimated Time Completion (ETC)

See ETC (Estimated Time Completion) definition.

Euroclaus Reaction

One of Sulphur Recovery Unit (SRU) reactions to convert acid gas into elemental sulphur.  Euroclaus is a trademark of Jacobs Nederland BV.  The reactions are as follows:

SO2 + 2 H2     ——->     1/x Sx + 2 H2O

SO2 + 3 H2     ——->     H2S + 2 H2O

SO2 + 2 CO    ——->     1/x Sx + 2 CO2

Exhaust Steam

Steam which is produced by turbine after being used to rotate turbine rotor.  Exhaust steam is cooled down and condensed in a surface condenser.  The steam condensate is then sent back to the utility section to be reused as Boiler Feed Water (BFW).

Fan

A device to route air or gas.  Fan is usually used to route combution air in a fired heater/furnace or to route air as a cooling media in an air cooler.  If it is used in area of fired heater/furnace, there is 2 types of fan, induced draft fan and forced draft fan.

FDF (Forced Draft Fan)

A fan which is used to produce positive pressure.  The fan is located at a point where air or gas enter the unit.

Final Boiling Point (FBP)

See End Point (EP) definition.

Fin Fan Cooler

See Air Cooler definition.

Fire Brick/Refractory

A brick which is fire proof.  It is used in a fired heater/furnace as an isolation inside the fired heater/furnace to avoid heat loss from fired heater/furnace cabin.

Fired Heater/Furnace

An equipment which is used to heat up fluid flowing inside tubes.  Heating media of fired heater is hot gas which is produced by burning fuel oil or fuel gas.

Flag Sheet/Process Flow Diagram (PFD)

A diagram showing process flow in a refinery processing unit.  It is usually a simple diagram which does not include detail note like P&ID.  Flag Sheet can include mass balance or important operating condition like flow, temperature, and pressure.

Flange

A device which is used to connect 2 pipes by using bolt and nut.  Gasket is used between 2 flanges to avoid any leakage.

Flare Stack

A stack which is used to burn flue gas from refinery processing unit to fulfill emission environmental standard.  Generally, there are 2 kinds of flare, sour flare (or acid flare) and sweet flare.  Sour flare is used for burning gas containing acid (mainly hydrogen sulfide, carbon dioxide, and ammonia), whereas sweet flare is used for burning free acid gas.

Flash Drum

A vessel which is used to separate process fluid into 2 fractions, which are lighter fraction and heavier fraction.  Lighter fraction is produced as top product in vapor phase, whereas heavier fraction is produced as bottom product in liquid phase.

Flash Point

Specific temperature which is hydrocarbon will flash.  It is usually used as a quality parameter of refinery product like kerosene and diesel.

Flash Zone

A part of distillation/fractionation column where the feed enters after being heated up at heat exchanger or fired heater/furnace.

Flue Gas

Gas which is produced by fuel oil or fuel gas burning process in a fired heater/furnace which is discharged to atmosphere through stack.  Sulphur dioxide and carbon dioxide are 2 main components of flue gas.  Flue gas is usually hot, so that it is often utilized as heating media in fired heater/furnace convection section to heat up hydrocarbon liquid or to produce steam or to heat up combution air.

Flushing Oil

Hydrocarbon liquid which usually has similar specification such as gas oil from Crude Distillation Unit (CDU).  It is usually used to swap refinery processing unit system from heavy hydrocarbon liquid in the beginning of the unit start up after the unit shutdown.  It is also used to wet catalyst in reactor.

Forced Draft Fan

See FDF definition.

Fractionation

See Distillation definition.

Fractionation Column

See Column definition.

Freezing Point

Specific temperature which is hydrocarbon liquid will freeze.  It is usually used as a quality parameter of refinery product like aviation turbine fuel (avtur).

Fresh Feed

Feed to refinery processing unit which is taken from tank or directly from other refinery processing unit (straight run feed).

Fuel Gas

Gas which is used as fuel for fired heater/furnace or boiler.  Fuel gas is usually in the form of off gas product of refinery processing unit or Liquid Petroleum Gas (LPG).

Fuel Oil

Hydrocarbon liquid which is used as fuel for fired heater/furnace or boiler.  Fuel oil is usually in the form of Low Sulphur Waxy Residue (LSWR) or atmospheric residue.

Furnace

See Fired Heater definition.

Gas Freeing/Purging

An activity in the beginning of start up or in the shutdown process to remove gasses, such as oxygen, hydrogen, and hydrocarbon, from the refinery processing unit system.  Gas freeing is done in the beginning of the start up to avoid unexpected situation, such as explosion, because of any remained gas exists in the system.  Gas freeing is done during shutdown to ensure that the system is gas free so that equipment, such as drum or distillation column, can be open safely during shutdown for maintenance.

Gasket

A device that is installed between 2 flanges to avoid any leakage around the connection.

Gas Oil

Hydrocarbon fraction which is heavier than kerosene having boiling point between 310 to 371 oC.  Gas oil is produced from some refinery processing units, such as Crude Distillation Unit/CDU (Light Gas Oil/LGO and Heavy Gas Oil/HGO), High Vacuum Unit/HVU or Vacuum Distillation Unit/VDU (Light Vacuum Gas Oil/LVGO and Heavy Vacuum Gas Oil/HVGO), Hydrocracker Unibon (Diesel Oil), and Delayed Coking Unit (Light Coker Gas Oil/LCGO and Heavy Coker Gas Oil/HCGO).

Gas Treating

Refinery process to dry out gas or to remove acid compounds.  Gas Treating to dry out gas is usually used in LPG plant, LNG plant, Air Separation Unit, and Gas Distribution area.  It is used to remove compounds which are possible to plug at very low temperature, such as H2O and CO2.  Gas Treating to remove acid compounds (such as H2S, CO2, and Mercaptan) is usually used in Gas Plant, Refinery, and Refinery Product Distribution area.  Some gas treating process are Amine Unit, Carbonate Process, Benfield Process, Seaboard Process, and Girbotol Process.

GCV (Gross Calorific Value)

See HHV (Higher Heating Value) definition.

Girbotol Process

Gas treating process to remove acid compounds by using Potassium Carbonate (K2CO3) and an inorganic compound as activating agent.  The reactions are as follows:

6CO2 + 2K3AsO3 + 3H2O   <——->    6KHCO3 + As2O3

CO2 + K2CO3 + H2O   <——->    2KHCO3

Green Coke

One of Delayed Coking Unit (DCU) products which results from thermal cracking of heavy hydrocarbon fraction.  Green coke is in solid form like coal.  Green Coke can be sold to be used as fuel like coal or can be further processed to be Calcined Coke.    Cancined coke is further processed to be anode.  To produce Calcined Coke, Green Coke is processed in a calciner to remove water content (reduce moisture content), reduce volatile matter, and increase Vibrated Bulk Density (VBD).

Gross Calorific Value (GCV)

See HHV (Higher Heating Value) definition.

Hammering

Loud sound which results from condensate which volume expands because of high temperature.  At 100 oC, water expands 1700 times its original volume.  That is why condensate in the steam system must be avoided.  It is avoided by equipping steam system by steam trap to separate condensate from steam system.

HCGO (Heavy Coker Gas Oil)

One of Delayed Coking Unit (DCU) products which is taken from main fractionation column.

Health, Safety, and Environmental (HSE)

A term which is used for any matter concerning with Health, Safety, and Environmental.  In some refineries, there is a specific department named Health, Safety, and Environmental (HSE) department which handles all Health, Safety, and Environmental issues/matters.  In some other refineries, HSE is sometimes split into 2 departments, Environmental and Health Department (EHD) and Security, Information & Technology, and Safety (SIS) or in some refineries create Corporate Safety and Fire Protection Department (CSFD) instead of SIS.

Heavy Coker Gas Oil

See HCGO definition.

HCU (Hydro Cracker Unibon)

A refinery processing unit which processes heavier hydrocarbon liquid by using catalytic cracking principle to produce lighter products, such as LPG (Liquid Petroleum Gas), Light Naphtha, Heavy Naphtha, Light Kerosene, Heavy Kerosene, and Diesel.  HCU feed can be Naphtha, Kerosene, Diesel, or Gas Oil.  If its feed is naphtha, then the product will be LPG.  If its feed is Kerosene, then the product will be LPG and Naphtha.  If its feed is Diesel, then the product will be LPG, Naphtha, and Kerosene.  If its feed is Gas Oil, then the product will be LPG, Naphtha, Kerosene, Diesel, and Lube Based Oil.

Heat Exchanger

An equipment which is used as heat exchange between 2 fluids.  Generally, there are 2 types of heat exchanger which are often used in a refinery, shell & tube exchanger and fin fan cooler.

Heating up

An activity to increase temperature (usually for reactor or fired heater/furnace or refinery processing unit) gradually depending on Standard Operating Procedure (SOP).  It is usually done during unit start up or fired heater/furnace dry out process.  Heating up rate of each refinery processing unit is different.  Common rate for heating up of a fired heater/furnace is 20-30 oC/hour to avoid any shock of temperature change which possibly cause problem to its refractory.  For Hydro Cracker Unibon (HCU) reactor, common rate for heating up is 17 oC/hour up to 290 oC, 10 oC/hour from 290 to 370 oC, and 1 oC/hour from 370 oC to operating temperature (around 400 oC).

Heavy Naphtha

See Naphtha definition.

Heavy Kerosene

See Kerosene definition.

HHV (Higher Heating Value)

Unit of Measurement of fuel, which is the amount of heat released by combusting a specified quantity (initially at 25 °C or another reference state) and returning the temperature of the combustion products to 150 °C.  HHV calculations assume that all of the water in a combustion process is in a liquid state after a combustion process, opposed to LHV.  It is also called Gross Heating Value (GHV) or Gross Calorific Value (GCV).  LHV is much more often to be used in calculation compared to HHV, because usually condensation of the combustion products is impratical or heat at a temperature below 150 °C cannot be put to use.

Higher Heating Value (HHV)

See HHV (Higher Heating Value) definition.

High Octane Motor Gasoline Component (HOMC)

Gasoline component which has high octane (> 90).  High Octane Motor Gasoline Component is usually produced by Catalytic Reforming (Platforming) unit.  It is also called as reformate.

High Vacuum Unit (HVU)/Vacuum Distillation Unit (VDU)

A refinery processing unit which processes Atmospheric Residue from Crude Distillation Unit (CDU) based on distillation principle at low pressure to produce Light Vacuum Gas Oil (LVGO), Heavy Vacuum Gas Oil (HVGO), and Short Residue.  It is operated by the same principle like Crude Distillation Unit (CDU), but with different operating pressure range.  It is operated at vacuum pressure (15-35 mmHgA), whereas Crude Distillation Unit (CDU) is operated at atmospheric pressure.

HOMC

See High Octane Motor Gasoline Component (HOMC) definition.

Hook Up

Piping connection which is usually used to measure fluid pressure in a system so that it can be read by transmitter or pressure gauge.  It is also used as a term for piping connection which is installed in some specific levels (usually in 2 positions, upper and lower level) to measure liquid level in a vessel.

HSE (Health, Safety, and Environmental)

See Health, Safety, and Environmental definition.

HVU (High Vacuum Unit)

See High Vacuum Unit (HVU)/Vacuum Distillation Unit (VDU) definition.

Hydraulic Horse Power

Power which is needed to pump fluid in a pump or a compressor.

Hydrobon

See Catalytic Reforming/Platforming definition.

Hydrocarbon

Chemical compound which comprises of carbon and hydrogen bonds as its main components.

Hydro Cracker Unibon

See HCU (Hydro Cracker Unibon) definition.

Hydrogen to Hydrocarbon Ratio

Ratio of mass flow of hydrogen contained in recycle gas to mass flow of hydrocarbon liquid (feed).  This ratio is usually used in refinery processing units which use hydrogen to convert feed to be products.

Hydrogen Plant

A refinery processing unit which converts treated gas from Amine Unit to be hydrogen product which has high purity.  In some other refineries, hydrogen feed is taken from Ethane Cracker.  If Hydrogen Plant uses Benfield system, the Hydrogen product purity is around 97%, whereas if Hydrogen Plant uses Pressure Swing Absorber (PSA), the Hydrogen product purity can reach 99.99%.  Hydrogen product is used in some refinery processing units, such as Hydro Cracker Unibon (HCU), Fluid Catalytic Cracking Unit (FCCU), Hydro Treating Unit (HTU), etc.

Hydro Treating

Treating of hydrocarbon fluid by using hydrogen and catalyst.  Two common Hydro Treating processes in refinery are Naphtha Hydro Treating, Distillate Hydro Treating.  In HCU, there is also Hydro Treating process, which is usually happened in the first step before Hydro Cracking process to treat hydrocarbon before Hydro Cracking process.

IBP (Initial Boiling Point)

According to American Society for Testing and Materials petroleum-analysis distillation procedures, IBP is the recorded temperature when the first drop of distilled vapor is liquefied and falls from the end of the condenser.

Impeller

Part of a pump whose shape is like propeller equipped with blade to give force to the fluid by centrifugal force so that it can increase fluid energy.

Incinerator

Fired heater/furnace which is used to burn organic substance to convert it into ash, flue gas, and heat.  The flue gas can be used to generate electric power or to produce steam.  According to the European Waste Incineration Directive, incineration plants must be designed to ensure that the flue gases reach a temperature of at least 850 °C (1,560 °F) for 2 seconds in order to ensure proper breakdown of toxic organic substances.

Induced Draft Fan

A fan that is used to produce mechanical draft.  The fan is located at a point where air or gas leave the unit.

Initial Boiling Point

See IBP definition.

Instrument Air

It is like plant air with pressure around 6 kg/cm2 but with lower water content.  It is used in a refinery for instrumentation system such as energize control valve to open and close, energize Emergency Isolation Valve (EIV), etc.

Intermediate Tank

A tank which is used as a temporary storage of a refinery processing unit product which later will be processed in other refinery processing units.

Isometric Drawing

3D drawing which shows position, dimension, and shape of equipment or piping system like actual condition in the field.

JP-5

It stands for Jet Propellant-5.  It is used by military as aircraft fuel.  JP-5 is the US Navy’s primary jet fuel.

JP-8

It stands for Jet Propellant-8.  It is used by military as aircraft fuel.  JP-8 is one of the jet fuels used by the U.S. Air Force.

Kerosene

Refinery product, fraction heavier than Naphtha, which usually has distillation range between 150 and 310 oC.  In a distillation column like in HCU (Hydro Cracker Unibon) or in a Splitter like in DHDT (Distillate Hydro Treating Unit), Kerosene can be split into Light Kerosene (which has API gravity around 49 and distillation range between 150 and 220 oC) and Heavy Kerosene (which has API gravity around 42 and distillation range between 200 and 310 oC). Kerosene can be split into Like Kerosene and Heavy Kerosene.  Kerosene is produced from CDU (Crude Distillation Unit), HCU (Hydro Cracker Unibon), and DHDT (Distillate Hydro Treating Unit).

Knock Out Drum (KOD)

A drum which is used to separate liquid (which may be contained in gas) from gas to avoid any liquid carry over to downstream which may be harmful for downstream processes. Liquid is separated at the bottom of the drum, whereas gas is routed out from top of the drum.

LCGO (Light Coker Gas Oil)

It is one of DCU (Delayed Coking Unit) products.  It has API gravity around 43 and it has distillation range between 140 and 350 oC.

Let Down

See Steam Let Down definition.

Level Glass

A device to measure liquid level of a vessel or a drum or a distillation column.  It is installed to know actual level in the field to be compared with measurement by displacer which is shown in DCS.

LHV (Lower Heating Value)

Unit of Measurement of fuel, which is the amount of heat released by combusting a specified quantity (initially at 25 °C or another reference state) and returning the temperature of the combustion products to 150 °C.  LHV calculations assume that the water component of a combustion process is in vapor state at the end of combustion, opposed to the Higher Heating Value (HHV).  It is also called Net Heating Value (NHV) or Net Calorific Value (NCV).  LHV is much more often to be used in calculation compared to HHV, because usually condensation of the combustion products is impratical or heat at a temperature below 150 °C cannot be put to use.  See HHV (Higher Heating Value) definition.

Light Coker Gas Oil

See LCGO definition

Light Naphtha

See Naphtha definition.

Light Kerosene

See Kerosene definition.

Liquid Petroleum Gas (LPG)

Light fraction which mainly comprises of C3 and C4.  At room temperature and atmospheric pressure, LPG is in gas phase.  Therefore, LPG is usually stored in high pressure and/or low temperature.  LPG specification to market usually contains C2 < 0.2 vol% and C5 < 2 vol%; the rest is C3 and C4.

Liquid Treating

Refinery process to purify products by contacting it with other substances.  Some examples of Liquid Treating in refinery are Doctor Treatment, Caustic Wash (Merox Process or Solutizer Process), Edeleanu Process, Solvent De-asphalting, Aromatic Extraction, Methyl Ethyl Ketone treating, Solid Bed Sweetening (Sponge Process or Molecular Sieves), Clay treating, and Desalter.

Long Residue

See Atmospheric Residue definition.

Lower Heating Value

See LHV (Lower Heating Value) definition.

Low Sulphur Waxy Residue (LSWR)

Refinery by product.  It is residue which has low sulphur content.  It is mostly Long Residue and Vacuum Residue mixed with little Diesel to meet specification.

LPG (Liquid Petroleum Gas)

See Liquid Petroleum Gas (LPG) definition.

LSWR (Low Sulphur Waxy Residue)

See Low Sulphur Waxy Residue (LSWR) definition.

Lube Base Oil

Lube Base Oil plant product to which other oils or substances or additives are added to produce lube oil or lubricant.

Lube Oil

In refinery it is used at a pump and a compressor to lubricate the rotating part like shaft or rotor.

Main Control Room (MCR)

A room where consoles are placed.  It is the place where DCS (Distributed Control System) is located.  From this place all important operating condition can be monitored and controlled by console operator.

Make Up Gas

Hydrogen rich gas, usually with purity more than 90%, which is usually used as make up to be injected to a system to increase hydrogen purity in recycle gas.  Make up gas is also used to maintain system/reactor pressure.

Manhole

A hole attached to vessel side or top where persons can enter to clean it up or to inspect it during its maintenance.

MBCD (Thousand Barrels per Calendar Day)

It is a unit of measurement to indicate a refinery processing unit capacity for each calendar day.  It is usually used for hydrocarbon liquid.

MBSD (Thousand Barrels per Stream Day)

It is a unit of measurement to indicate a refinery processing unit capacity for each day of operation.  It is usually used for hydrocarbon liquid.

MCR

See Main Control Room (MCR) definition.

Mechanical Seal

Part of rotating equipment which is used to seal off pump system to avoid leakage of fluid from its casing.

MEK (Methyl Ethyl Keaton) Treating

Liquid treating process to absorb paraffin wax from hydrocarbon fraction (usually lube oil feedstock).

MMSCFD (Million Standard Cubic Feet per Day)

It is a unit of measurement to indicate a refinery processing unit capacity for each day of operation.  It is usually used for hydrocarbon gas.

Mogas (Motor Gasoline)

Mogas stands for motor gasoline.  It is gasoline used for vehicle.

Molecular Sieves

Liquid treating, which is classified as Solid Bed Sweetening, using adsorbent to remove H2S, CO2, mercaptan, and H2O even they are already in low concentration.

Naphtha

One of refinery products, fraction heavier than LPG (Liquid Petroleum Gas) and lighter than Kerosene, which usually has API gravity between 60 to 70 and usually has distillation range between 50 to 165 oC.  In CDU (Crude Distillation Unit) and DCU (Delayed Coking Unit) it is produced as one stream Naphtha which is sent to NRU (Naphtha Rerun Unit) or NHDT (Naphtha Hydro Treating Unit) to be split into Light Naphtha (which has API gravity around 70 and has distillation range between 40 to 165 oC) and Heavy Naphtha (which has API gravity around 60 and has distillation range between 70 to 170 oC).  HCU (Hydro Cracker Unibon) also produces Light Naphtha and Heavy Naphtha.  Light Naphtha is taken as final product to be used as one of gasoline blending component.  Heavy Naphtha is usually further processed in a catalytic reforming (platforming) unit to convert it into high octane motor gasoline component, commonly called as reformate (octane number > 90; usually 92 or 95 or 98).

Naphtha Hydro Treating Unit (NHDT)

A refinery processing unit which treats naphtha to be used as feed of a Catalytic Reforming (Platforming) unit (it reduces naphtha sulphur content, nitrogen content, metal content, and other impurities).  The unit also splits Naphtha into Light Naphtha and Heavy Naphtha.  Light Naphtha is taken as final product to be used as gasoline blending component, whereas Heavy Naphtha is sent to a Catalytic Reforming (Platforming) unit to produce High Octane Motor Gasoline Component (HOMC), commonly called as reformate, which has octane number > 90 (usually 92, 95, or 98).

Naphtha Rerun Unit (NRU)

See Naphtha Hydro Treating Unit (NHDT) definition.

NCV (Net Calorific Value)

See
LHV (Low Heating Value) definition.

Net Calorific Value (NCV)

See LHV (Low Heating Value) definition.

Net Heating Value (NHV)

See LHV (Low Heating Value) definition.

NHDT (Naphtha Hydro Treating Unit)

See Naphtha Hydro Treating Unit definition.

NHV

See Net Heating Value (NHV) definition.

NRU (Naphtha Rerun Unit)

See Naphtha Hydro Treating Unit (NHDT) definition.

Nitrogen Plant

A refinery processing unit that produces Nitrogen by separating air to be Nitrogen and Oxygen.  In a refinery, Nitrogen is used during start up, shutdown, and normal operation.  During start up, it is used to purge system, reactor, or vessel; it is also used during the first time of compressor start (in Hydro Cracker Unibon, it is used to press up pressure system up to 35 kg/cm2).  During shutdown, it is used during catalyst skimming. During normal operation, it is used to balance reaction in a reactor (in Catalytic Reforming/Platforming Unit or in Fluid Catalytic Cracking Unit); it is also used for sweeping in case of temperature excursion or temperature runaway in a reactor (mainly in Sulphur Recovery Unit reactors).

Octane Number

It is quality parameter for gasoline product.  The octane number of a fuel is measured in a test engine, and is defined by comparison with the mixture of 2,2,4-trimethylpentane (iso-octane) and heptane which would have the same anti-knocking capacity as the fuel under test: the percentage, by volume, of 2,2,4-trimethylpentane in that mixture is the octane number of the fuel. For example, petrol with the same knocking characteristics as a mixture of 90% iso-octane and 10% heptane would have an octane rating of 90.[1] This does not mean that the petrol contains just iso-octane and heptane in these proportions, but that it has the same detonation resistance properties. Because some fuels are more knock-resistant than iso-octane, the definition has been extended to allow for octane numbers higher than 100.

Off Gas

Refinery unit process product which is in gas phase (in room temperature).  It usually comprises of hydrogen, carbon dioxide, methane, and ethane.  It can be used as Fuel Gas or as feed to Hydrogen Plant.

On Stream

A term which is used to indicate that a refinery processing unit is already in normal operation (after completing start up process) and all products are already on-specification.  Usually, a refinery processing unit needs 2 to 5 days to get on-stream in a unit start up process.

Operating Manual

Manual which contains brief description about basis of design (process overview, material balance, feed and product specification, and Battery Limit condition), general description (process flow description, utilities/chemical/catalyst, control system, and general HSE system and equipment), operating procedures/instruction, and equipment & instrumentation list.

Orifice

A device to measure fluid flow in a piping system.  The form of orifice is a round plate with a small hole in the center.  Orifice measurement is based on pressure difference which results from orifice plat/hole.  This pressure difference is measured by transmitter and then it  is converted to 4-20 mA signal so that it can be shown in Distributed Control System (DCS).

Overhead Receiver

A vessel which is used to collect liquid resulted from vapor condensation in a distillation column top.  From overhead receiver, liquid can be taken as product or can be returned back to column as a reflux.

Overhead Temperature/Pressure

Temperature/Pressure at top of distillation/fractionation column.  In  distillation process, overhead temperature and pressure are important parameters to produce stable process and on-spec products.

Peak Temperature

Peak Temperature

The highest temperature measured in the reactor bed or the highest reactor bed temperature.

Peephole

A hole at the side of fired heater/furnace which is used to see inside fired heater/furnace cabin to monitor flame pattern, burner condition, and tube condition.

PFD (Process Flow Diagram)

See Flag Sheet definition.

Pilot Gas Burner

Small auxiliary gas burner which provides a flame to ignite a larger gas burner or to maintain flame stability.

P&ID (Piping & Instrumentation Diagram)

Diagram or drawing which contains drawing of refinery processing unit equipment and piping system completed with its instrumentation, control system, and piping size.

Piping & Instrumentation Diagram (P&ID)

See P&ID definition.

Plant Air

Air with around 6 kg/cm2 which is routed to refinery processing unit to be used for utility, such as to continuously purge flame scanner, to balance reaction in a reactor, or to do pneumatic test in the field.

Platforming

See Catalytic Reforming/Platforming definition.

Plot Plan

2 dimension drawing which shows position or location of equipment in a refinery processing unit as per actual condition in the field.

Pour Point

The lowest temperature at which it will still pour or flow under prescribed conditions.  It is a rough indication of the lowest temperature at which oil is readily pumpable.  It is also defined as a measure of the ability of a diesel fuel to operate under cold weather conditions.  It is usually used as one of diesel fuel quality parameters.  It can be different from one country to another, depends on the country condition.  Even in one country, it can also be different between summer and winter specification.  For example, in a tropical country, 65 oF as maximum limitation of Pour Point is acceptable.  Nevertheless, in Rocky mountain, Pour Point limitation is different between Summer and Winter season, 10 oF as maximum limitation of Pour Point during Summer season and -30 oF as maximum limitation of Pour Point during Winter season.

Pressure Gauge

A device to measure system or fluid pressure.  It is usually installed in the field and it is not connected to Distributed Control System (DCS).  If it is connected to DCS, it is called Pressure Indicator (PI).

Pressure Indicator

A device to measure system or fluid pressure.  It is connected to Distributed Control System (DCS), so that it can be seen from console.

Pressure Relief Valve (PRV)

A device which is used to discharge system pressure if there is over pressure in the system which will endanger the system.  It is also commonly called Pressure Safety Valve (PSV).  It is actuated by inlet static pressure and designed to open during an emergency or abnormal conditions to prevent a rise of internal fluid pressure in excess of a specified value.  The device may also be designed to prevent excessive internal vacuum.  API Recommended Practice 520 Part I & II are international standards which are usually followed for PSV sizing, selection, and installation.

Pressure Vessel

A vessel/container (cylindrical or spherical) which is capable of withstanding pressure.

Pre-wetting

One of refinery processing unit start up procedures which is used to wet catalyst inside reactors by using flushing oil.  Pre-wetting is conducted in refinery processing units using catalyst in their operation.  The main purpose of pre-wetting is to have uniform flow distribution in the reactor later after the unit is operated with designed feed.

PIM (Plant Instruction Manual)/SOP (Standard Operating Procedure)/WI (Work Instruction)

Manual which contains a detail procedure of refinery processing unit start up/shutdown (normal and emergency) or equipment start up/shutdown or fired heater/furnace dry out or catalyst loading or normal operating condition or equipment handover from operation to maintenance, etc.  The difference between PIM and Operating Manual is that Operating Manual is usually manual which is given by contractor/licensor which is usually general in describing instruction, while PIM usually contains detail instruction about what field operators/console operators/shift supervisors should do individually or in coordination one another or in coordination with other sections or with Shift Superintendent.  It is also usually completed with check list so that all procedures/instructions can be done correctly and in order.

PIMS (Plant Information Management System)

A system to collect and integrate information about a production process from different sources.  Examples of PIMS are Aspentech IP21, Osisoft PI, Honeywell PHD, Yokogawa Exaquantum, Wonderware Historian, and GeFanuc iHistorian.

Plant Information Management System (PIMS)

See PIMS definition.

Plant Instruction Manual

See PIM definition.

Process Flow Diagram (PFD)

See Flag Sheet definition.

Project Specification

A book which includes data of equipment, such as vessel, pump, compressor, heat exchanger, instrumentation, catalyst and chemical, etc., in a refinery processing unit which is preliminary design data that is later made in detail in data sheet or technical data book.

Pump

Equipment to transfer liquid from one place to other places by giving pressure to the liquid.  In a refinery, there are 2 common types of pump, centrifugal pump and reciprocating pump.  Centrifugal pump is usually used to transfer hydrocarbon liquid, whereas reciprocating pump is used for chemical injection.

Pumparound

Hydrocarbon liquid which is taken from distillation column liquid collector/drawoff returned back to the distillation column to be used as cooling media of hydrocarbon vapor inside the distillation column.  Usually, pumparound is taken from distillation column and is routed to some heat exchanger to be used as heating media, so that its temperature is much lower and it can be used as cooling media of hydrocarbon vapor inside the distillation column to adjust product specification, such as Final Boiling Point (FBP) and Pour Point.

Purging

See Gas Freeing definition.

Quench Gas

Recycle gas which is routed to reactor system to cool down reactor effluent before it enters another reactor.  It is also used to control the next reactor inlet temperature.  During emergency situation, like temperature excursion or runaway, it can be used to cool down reactor to drastically reduced temperature simultaneously with depressuring the system pressure to cut out reaction.

Radiation Section

Part of fired heater/furnace where fluid is heated up by using flame radiation of the burner.

Reaction Furnace

Thermal Stage of Sulphur Recovery Unit (SRU) process.  It is used to convert acid gas (H2S) to elemental sulphur by using high temperature.  The reactions are as follows:

H2S + 3/2 O2      ——->     SO2 + H2O + Heat

2H2S + SO2      <——->     3/2 S2 + 2 H2O – Heat

Reaction Furnace temperature is around 1000 oC (for processing amine acid gas, which mainly contains H2S and CO2) or around 1250 oC (for processing SWS gas, which mainly contains H2S and NH3).  Higher temperature for processing SWS gas is needed for ammonia decomposition.

Reactor

Vessel which comprises one or two or three catalyst beds where the chemical reaction, like cracking, treating, desulphurization, and Claus reaction, takes place.  Usually reactors are cylindrical and vertical, such as in NHDT, NRU, HCU, Catalytic Reforming/Platforming, FCCU, and Hydrogen Plant.  Nevertheless, in Sulphur Recovery Unit, it is usually built cylindrical and horizontal divided into 3 or 4 sections for each type of Sulphur Recovery reaction.

Reactor Effluent

Hydrocarbon fluid from reactor which results from chemical reaction or conversion in the reactor.  Then, usually, reactor effluent is condensed and fractionated to be products by distillation.

Reboiler

Equipment which is used to heat up hydrocarbon liquid bottom of distillation/fractionation column in order to produce vapor to be returned back to the distillation/fractionation column to be used as distillation/fractionation column heating media.  In the distillation/fractionation column, there is a contact between vapor produced by reboiler and hydrocarbon liquid resulted from feed flashing which will then increase the separation degree.

Reciprocating Compressor

A compressor using pistons driven by a crankshaft.  It can be either stationary or portable, can be single or multi-staged, and can be driven by electric motors or internal combustion engines.

Recycle Feed

Portion of product which is rerouted back as feed.  The purpose of having recycle feed is to increase reactor severity and simultaneously to decrease reactor load because recycle feed is actually already converted into product.

Recycle Gas

Hydrogen rich gas which is circulated continuously within reactor system by using recycle gas compressor.  Recycle gas hydrogen purity is usually maintained as high as possible (around 90%) to have high reaction conversion and to extend catalyst lifetime.  Recycle gas is usually used as reactant in refinery processing units using catalyst for treating and cracking, such as in HCU and NHDT.

Refractory

See Fire Brick definition.

Regenerated Catalyst

Catalyst which is already regenerated.  See Catalyst Regeneration definition.

Reid Vapor Pressure (RVP)

Quality measurement of light fraction hydrocarbon which indicates extent of vaporization.  It is used for Light Naphtha, Reformate or HOMC (High Octane Motor Gasoline Component), and LPG (Liquid Petroleum Gas).

Reflux

Hydrocarbon liquid which is returned back to distillation/fractionation column.  It can be hydrocarbon liquid which is gained from vapor condensation at the top of the column and returned back to the column as cooling media of hydrocarbon vapor at the top of the column in order to adjust/control product quality (which is usually called as top reflux).  It can also be pumparound (which is usually called as internal reflux).

Safety Instrumented System (SIS)

A form of process control usually implemented in industrial processes, such as those of a factory or an oil refinery.  The SIS performs specified functions to achieve or maintain a safe state of the process when unacceptable or dangerous process conditions are detected.  Safety instrumented systems are separate and independent from regular control systems but are composed of similar elements, including sensors, logic solvers, actuators and support systems.

Seaboard Process

Gas treating process to remove acid compounds by Sodium Carbonate (Na2CO3).  The reactions are as follows:

Na2CO3  +  H2S   <——->   NaHS  +  NaHCO3

Na2CO3  +  CO2  +  H2O  <——->    2NaHCO3

Sea Water

It is used as cooling media in heat exchangers.

Sea Water Cooler

Heat exchanger which is used as cooler by using sea water as its cooling media.

Sequence of Events (SoE)

List of Events related to Emergency Shutdown Device (ESD) or Safety Instrumentation System (SIS).  The SoE records any ESD/SIS which is activated.  It is used to track the root cause of Equipment/Unit trip.

Separator

Vessel which is used to separate process fluid to be gas phase, liquid phase, or sour water.  It can be High Pressure Separator (in HCU, it has operating pressure around 170 kg/cm2g) or Medium Pressure Separator (in HCU, it has operating pressure around 25 kg/cm2g) or Low Pressure Separator (in HCU, it has operating pressure around 7 kg/cm2g).

Sequence of Events (SoE)

Recorded events related to Emergency Shutdown Device.  All signals related to Emergency Shutdown Device are sent to SIS (Safety Instrumentation System) and recorded in Sequence of Events.

SG (Specific Gravity)

Ratio of the density of a substance to that of a standard substance. For solids and liquids, the standard substance is usually water at 39.2°F (4.0°C), which has a density of 1.00 kg/liter. Gases are usually compared to dry air, which has a density of 1.29 g/liter at 32°F (0°C) and 1 atmosphere pressure. Because it is a ratio of two quantities that have the same dimensions (mass per unit volume), specific gravity has no dimension. For example, the specific gravity of liquid mercury is 13.6, because its actual density is 13.6 kg/liter, 13.6 times that of water.

Shaft

Part of rotating equipment (pump or compressor) which is used to distribute mechanical energy resulted from motor or turbine to impeller so that it can increase fluid energy.

Short Residue/Vacuum Residue/Vacuum Bottom

Bottom product (residue) of Vacuum Distillation Column of High Vacuum Unit (HVU)/Vacuum Distillation Unit (VDU).

Shutdown

Activity to stop a refinery processing unit.  Shutdown procedure or detail instruction is written in a Plant Instruction Manual (PIM)/Standard Operating Procedure (SOP)/Work Instruction (WI) completed with check list so that all procedure can be done correctly and in order.  There are 2 kinds of Shutdown, Normal Shutdown and Emergency Shutdown.  Normal Shutdown is conducted if the Shutdown is previously planned, while Emergency Shutdown is conducted if the Shutdown is previously unplanned because of emergency situation to safe the unit operation.

Side Draw

See Draw off definition.

Side Stripper

Vessel which is a part of distillation/fractionation column which is used to purify product from distillation/fractionation column.  In the Side Stripper, steam (usually Low Pressure Steam) is injected as heating media to fractionate lighter fraction from the product.  The lighter fraction is routed back to distillation/fractionation column.  Side Stripper is usually used to adjust/control product quality.  For example, Diesel Side Stripper is used to adjust/control flash point of Diesel product, while Diesel pour point is controlled by controlling Diesel draw off temperature.

Sight Glass

A device which is used to ensure that fluid in the piping system is flowing.  It is also commonly used to measure lube oil level of a pump.

Skin Temperature

Temperature measurement at tube surface (in the fired heater/furnace) or at vessel/reactor.  It is used to identify the tube surface or reactor wall temperature so that their mechanical design limitations are not exceeded.

Skimming

A term for partial catalyst unloading.  During operation, catalyst usually experiences coking because of operation upset, such as less Hydrogen to Hydrocarbon Ratio (less Hydrogen purity in recycle gas or less recycle gas flow because of recycle gas compressor low performance) or temperature excursion/temperature runaway.  Catalyst is also used for desulphurization, denitrification, and demetalization.  Catalyst also sometimes adsorbs impurities, such as water carry over.  These all catalyst deactivation process (coking, desulphurization, denitrification, demetalization, impurities adsorption) are happened worse in the top layer of the catalyst.  If this catalyst deactivation is happened so fast compared to normal catalyst deactivation, catalyst skimming can be alternative instead of change out of catalyst.  Catalyst skimming is usually conducted in inert environment.  Reactor is injected with nitrogen (to avoid catalyst oxidation which will deactivate catalyst and which will possibly cause fire because of pyrite contained in the catalyst); catalyst is skimmed from top, usually around top 30 to 50 cm layer catalyst is skimmed, depending on catalyst condition.

Slop Oil

Off specification product results from a refinery processing unit.  During start up or shutdown activities or unit upset, there is possible to have off specification products.  These off specification products are sent to Slop Oil tank.  Slop Oil tank also receives oil from Oil Separator in Waste Water Treatment Plant (WWTP).  Oil Separator receives oil and water from refinery processing units through Oil and Water Sewer (OWS).  This oil is usually from sampling points or drains.  Slop oil from Slop Oil tank can be reprocessed in Crude Distillation Unit (CDU) with maximum of 5 vol% on feed of CDU in order to maintain the unit stability, mainly related to water content of Slop Oil.

Smoke Point

The maximum flame height in millimeters at which kerosene or jet fuel or aviation turbine fuel will burn without smoking, tested under standard conditions.  It is used as a measure of the burning cleanliness of jet fuel and kerosene.

Snubber

Vessel which is used to maintain gas flow continuity and also to separate water from the gas.  Snubber is usually a part of reciprocating compressor, installed at suction and discharge of the compressor.

Snuffing Steam

Steam which is used to sweep flammable gas from fired heater/furnace.  Snuffing Steam line is usually installed in parallel with fuel gas to burner.  After a burner is stopped, then snuffing steam is open for a while to sweep flammable gas around the burner.  Snuffing Steam lines are usually also operated/open during fired heater/furnace trip or emergency shutdown.

SoE (Sequence of Events)

Recorded events related to Emergency Shutdown Device.  All signals related to Emergency Shutdown Device are sent to SIS (Safety Instrumentation System) and recorded in SoE.

Solid Bed Sweetening

Liquid treating which uses solid laid in bed/vessel to remove H2S, O2, CO2, and H2O.  Molecular Sieves and Sponge Process are two Common Solid Bed Sweetening processes in refinery.  See Molecular Sieves definition and Sponge Process definition.

Solvent De-asphalting

Extraction process to remove asphaltenes from Lubricating Oil.  Propane, Butane, Pentane, or Hexane are used as solvent.

SOP (Standard Operating Procedure)

See PIM (Plant Instruction Manual) definition.

Soot Blower

A device which is used to clean soot or carbon on the surface of convection section tubes by spraying steam (usually Low Pressure Steam) into the convection section for short period of time (15-30 minutes).  It is usually done regularly (once or twice a week).

Sour Water

Waste water resulted from refinery processing units.  Sour Water from each refinery processing unit is re-processed in Sour Water Stripping Unit (SWS) to remove H2S and ammonia.  The stripped water can be directly sent to Waste Water Treatment Plant (WWTP) or can be re-use as cooling water in a water cooler or can be re-use as wash water in NHDT or HCU.  In WWTP, oil is separated from the Stripped Water.  From WWTP the water then is sent to the sea/river and the oil is sent back to Slop Oil tank to be reprocessed in CDU.

Sour Water Stripping Unit (SWS)

Refinery processing unit which processes sour water from all refinery processing units by removing its impurities, such as H2S and ammonia.

Specific Gravity (SG)

See SG (Specific Gravity) definition.

Spillback

Fluid which is recycled from pump discharge to pump suction.  It is used to maintain minimum flow of the pump so that design minimum flow can be achieved.

Splitter

Fractionation column which is used to separate 2 different hydrocarbon fractions which have small different in boiling range.  An example of Splitter is Kerosene Splitter, which is used to separate Light Kerosene and Heavy Kerosene.  See Stripper definition for the difference between Splitter and Stripper.

Sponge Process

Liquid treating, which is classified as Solid Bed Sweetening, to remove H2S and O2 by using sponge Ferro.  The reactions are as follows:

2Fe2O3 + 6H2S   ——->    2Fe2S3 + 6H2O

2Fe2S3  +  3O2    ——->    2Fe2O3 + 6S

Stack

Part of fired heater/furnace or boiler which is used to discharge flue gas to atmosphere.  The term “Stack” is also used for flare, it is called Flare Stack (see Flare Stack definition).

Standard Operating Procedure

See PIM (Plant Instruction Manual) definition.

Standing Order (SO)

Daily operation instruction which is written by Refinery Processing Unit Chief/Head.  It comprises of instruction to adjust/control operating condition (increase/decrease feed, mode of operation, etc.), manpower management, and other valuable information needed by operation personnel.  Usually for refinery processing unit load/feed flow, Refinery Processing Unit Chief/Head will refer to instruction given by Production Planning Department.

Start up

Activity to start a refinery processing unit.  Start up procedure is written in Start up PIM (Plant Instruction Manual)/SOP (Standard Operating Manual)/WI (Work Instruction).  It must be followed correctly and in order.

Steam

Pressurized steam which results from boiler or steam generator.  It is used to generate turbine or as heat exchanger heating media or as steam tracing or as reactant in Hydrogen Plant.  In a refinery, steam is classified based on its pressure; High Pressure Steam is usually Steam with pressure around 40 kg/cm2g or 60 kg/cm2g (depends on the refinery necessity on the steam), Medium Pressure Steam is usually Steam with pressure around 11-13 kg/cm2g), and Low Pressure Steam is usually Steam with pressure around 3.5 kg/cm2g).

Steam to Carbon Ratio

Ratio of steam flow to total carbon in the feed gas.  This parameter is used in Hydrogen Plant.  Actual Steam to Carbon Ratio in Hydrogen Plant must always be higher than its minimum limit to avoid coking at the catalyst surface, mainly for steam reformer catalyst.

Steam Generator

One type of heat exchangers which is used to produce steam (usually High Pressure Steam and Medium Pressure Steam).  The heating media is usually hydrocarbon liquid (from pumparound) or hydrocarbon gas (like in Hydrogen Plant).

Steam Let Down

System to reduce steam pressure, usually from High Pressure Steam to Medium Pressure Steam.

Steam Tracing

Steam coil or tubing which is wound around a pipe to avoid fluid frozen inside the pipe.  The service fluids inside the pipe are usually heavy hydrocarbon and liquid sulphur.

Steam Trap

A device which is used to separate condensate from steam flow to avoid any condensate in the steam system which may cause hammering.

Steam Turbine

Turbine which utilizes High Pressure Steam or Medium Pressure Steam as energy source to produce power.  Power resulted from steam turbine can be used as driver for pump or compressor or electric power generation.

Storage Tank

Tank which is used to store refinery processing unit feeds and products.  General types of storage tank in a refinery are Fixed Roof Tank which is used for non-volatile hydrocarbon liquid, Floating Roof Tank which is used for volatile hydrocarbon liquid, and Spherical Tank which is used for LPG (Liquid Petroleum Gas).

Straight Run

Hydrocarbon fractions resulted from CDU (Crude Distillation Unit) without chemical reaction or molecular modification.  This term is often used for Naphtha, Straight Run Naphtha.

Stripper

Fractionation column which is used to strip lighter fraction from heavier fraction, such as Light Naphtha Stripper (to strip LPG/Liquid Petroleum Gas from Light Naphtha product).  Another type of Stripper is Side Stripper (see Side Stripper definition).  The difference between Stripper and Splitter is that Stripper is used to separate 2 different hydrocarbon fractions which have big different in boiling point range (for example LPG and Light Naphtha), while Splitter is used to separate 2 different hydrocarbon fractions which have small different in boiling range (for example Light Kerosene and Heavy Kerosene).

Stripping Steam

Steam which is injected into distillation column bottom or side stripper bottom.  It is used as heating media to reduce hydrocarbon partial pressure so that light fractions can be evaporated at lower temperature.

Suction

Upstream part of rotating equipment (pump or compressor) which sucks service fluid to be transferred.

Sulphur Recovery Unit (SRU)

Refinery processing unit which converts acid gas (Amine Acid Gas and SWS Gas) into elemental sulphur.  It can only comprises of 2 stage of process, thermal stage (Reaction Furnace) and Claus reactor, or it can also comprises of more than 2 stage of process (added by Euroclaus reactor and Superclaus reactor, which are trademarks of Jacobs Nederland BV).  See Reaction Furnace definition for thermal stage reaction and see Claus Reaction definition for Claus Reaction.

Superclaus Reaction

One of Sulphur Recovery Unit (SRU) reactions to convert acid gas into elemental sulphur.  Superclaus is a trademark of Jacobs Nederland BV.  The reaction is as follows:

H2S + 0.5 O2     ——->     1/x Sx + H2O

Superheater

A device which is used to heat up saturated steam in order to get superheated steam.

Surface Condenser

Air Cooler which is used to condense exhaust steam from turbines in the refinery processing units.

Surge Drum

Vessel which is used to store hydrocarbon liquid before being processed.  It is used to avoid any feed fluctuation which may be happened in the upstream unit or from feed tank so that feed to the unit can be stable.  Surge Drum is also used to settle water content which may be carried over from upstream unit or feed tank.

Sweeping

An activity to push out liquid from system (usually reactor).  Sweeping is usually done in refinery processing units having reactors.  It is usually done by circulating hydrogen rich gas or recycle gas.  It is very useful mainly to make catalyst unloading easier because there is already no liquid in the reactor/catalyst.

Technical Data Book

Book which comprises of refinery processing unit equipment data (datasheet, material test data, detail drawing, etc.).

Temperature Excursion/Temperature Runaway

Situation where catalyst bed temperature is rapidly increased suddenly exceeding maximum operating design temperature and maximum design delta temperature limit.  Delta temperature is the difference between reactor bed peak temperature and reactor inlet temperature.  For example in Hydrocracker Unibon with Amorphous catalyst, maximum operating design temperature is 454 oC and maximum design delta temperature is 28 oC (in Fresh Feed reactor) or 14 oC (in Recycle Feed reactor).  In this case, temperature excursion or temperature runaway is the situation where there is one or more reactor bed temperatures more than 454 oC and delta temperature more than 28 oC (in Fresh Feed reactor) or more than 14 oC (in Recycle Feed reactor).

Thermal Cracking

Refinery process which utilizes heat for cracking hydrocarbon.  Two famous refinery processes utilizing thermal cracking process are Delayed Coking Unit (DCU) and Visbreaker.

Thermal Oxidizer

Fired heater/furnace which is used to burn remain acid gas to convert it into flue gas and heat so that it is safe to discharge it to atmosphere.  The flue gas can be used to generate electric power or to produce steam.  It is one of Sulphur Recovery Unit (SRU) equipment.  Its normal temperature is around 750 oC.

Thermocouple

A device to measure fluid temperature of inside distillation/fractionation column, fired heater/furnace cabin, heat exchanger inlet/outlet, etc.  Thermocouple can be connected to Distributed Control System (DCS), then it is called Temperature Indicator/Temperature Controller, so that it can be monitored or controlled by console operator.

Ton Standard Refinery Fuel (TSRF)

Unit of measurement which is used to measure fuel consumption of a heater or a refinery processing unit.  TSRF = calorie (in kcal)/9800000.

Topping Unit

See Crude Distillation Unit (CDU) definition.

Transmitter

A device which is used to send signal from a refinery processing unit field to Distributed Control System (DCS) so that it can be monitored or controlled by console operators.  It can be used for flow, temperature, or pressure.  Transmitter works by transmitting pneumatic measurement (pressure difference) to 4-20 mA signal.

Tray

Part of distillation/fractionation column where vapor phase and liquid phase are in contact in order to separate light fraction from heavy fraction.  Tray types are various, such as sieve tray, valve tray, bubble cap tray, and packing tray.

Treating

Hydrocarbon process to remove impurities from refinery products.  There are many treating processes in refinery, but in general it can be classified into 3 categories, namely Hydro Treating, Liquid Treating, and Gas Treating (See Hydro Treating definition, Liquid Treating definition, and Gas Treating definition).

Trip

Situation when equipment (pump, compressor, fired heater/furnace, control valve, or Emergency Isolation Valve) is immediately stopped.  Trip can be happened because of overload or Emergency Shutdown Device (ESD) system activation.  See Emergency Shutdown Device (ESD) definition.

TSRF

See Ton Standard Refinery Fuel definition.

Universal Oil Product (UOP)

American company which is an international provider of technologies (process licenses), products (catalysts and adsorbents) and services (technical assistance, training, consulting) to the petroleum refining, gas processing, petrochemical production and major manufacturing industries.

Vacuum Bottom

See Short Residue definition.

Vacuum Residue

See Short Residue definition.

Vacuum Distillation Unit (VDU)

See High Vacuum Unit (HVU) definition.

Valve

A device to adjust fludi flow or pressure.  Common types of valves to be used in refinery are Gate Valve, Globe Valve, and Butterfly Valve.  Valve can be connected to Distributed Control System (DCS), which is called Control Valve.  See Control Valve definition.

Venting

Pipe which is used to vent or to empty a system (piping, pump, or vessel) from gas.  Venting is usually located at highest point of the system, opposed to Drain.  The difference between Venting and Drain is that Venting is for gas, while Drain is for liquid.  See Drain definition.

Vessel

Equipment which is not only used as container, but also as other refinery purposes.  Distillation/fractionation column, Knock out Drum (KOD)/flash drum, overhead receiver, surge drum, separator, side stripper, Stripper, Splitter, and Debutanizer are classified as Vessel.

VM (Volatile Matter)

Substance which is very easy to evaporate.  It is commonly used as Coke (Green Coke or Calcined Coke) quality parameter/specification.  Coke (Green Coke or Calcined Coke) is one of Delayed Coking Unit (DCU) products.  Volatile matter is determined by heating the coal to 950 oC under carefully controlled conditions and measuring the weight loss, excluding weight of moisture driven off at 105 oC.

Volatile Matter (VM)

See VM (Volatile Matter) definition.

Waste Heat Boiler

Boiler which is used to produce steam (usually High Pressure Steam) by utilizing heat from reactor/fired heater flue gas, such as flue gas from Steam Reformer (in Hydrogen Plant), or acid gas from Reaction Furnace (in Sulphur Recovery Unit), or flue gas from fired heater/furnace (in other refinery processing units).

Water Boot

Part of separator which is used to collect sour water or process water resulted from separation in the separator.  The water is then routed to Sour Water Stripping Unit.

WI (Work Instruction)

See PIM definition.

Work Instruction

See PIM definition.

Hydrocracker Troubleshooting: Troubleshoot Hydrocracker Unibon Main Fractionation Column High Bottom Yield

by The Quality Control Project Team (with Adhi Budhiarto as the Process Engineer)

1.  Background

The Hydro Cracker Unibon is a process which converts Heavy Vacuum Gas Oil (HVGO) from Vacuum Distillation Unit (VDU) and Heavy Coker Gas Oil (HCGO) from Delayed Coking Unit (DCU) to be lighter fractions having higher prices, such as Liquid Petroleum Gas (LPG), Naphtha, Kerosene, Aviation Turbine jet fuel (Avtur), and diesel.

Generally, Hydro Cracker Unibon comprises of 2 sections, as follows:

1. Reactor Section

In this section, long chain hydrocarbon feed experiences cracking reaction which is continued with olefin and aromatic saturation by hydrogen with help of catalyst, to produce shorter chain hydrocarbon fractions.  The process is happened in 2 fresh feed reactors and 1 recycle feed reactor.  The reaction is happened at high pressure and temperature (+ 170 kg/cm2 and + 400 oC).

2. Fractionation Section

In this section, reactor effluent is separated by distillation process in one main fractionation column, one debutanizer column, and some product strippers.

Some reactions happened in the reactors are: cracking reaction, olefin saturation, sulphur removal, and nitrogen removal.  Sulfur removal and nitrogen removal are reactions converting organic sulphur and nitrogen to H2S and NH3.  H2S and NH3 produced from the reactions will be converted to NH4HS (ammonium hydrosulfide).  At low temperature NH4HS will be precipitated and also possible to be source of tube corrosion and erosion.  NH3 deactivates catalyst because active side of catalyst is acid base and H2S accumulates in recycle gas which will reduce recycle gas purity used as cracking media in the reactors.  Reduced recycle gas purity will reduce reaction conversion so that it will potentially produce some off spec diesel which then has to be down grade to be LSWR (Low Sulphur Waxy Residue) product having only 42% of diesel price.

To avoid those negative effects, in Hydro Cracker Unibon wash water is injected to Reactor Effluent Air Coolers (REAC) using plunger pumps for fresh feed and recycle feed reactors.  Wash water injection is used to:

  1. Dissolve H2S to avoid recycle gas purity reduction which will potentially produce off spec diesel.
  2. Dissolve NH3 to avoid catalyst deactivation.
  3. Dissolve NH4HS to avoid any deposit or plugging inside REAC tubes.
  4. Reduce corrosion product.

Wash water injection recommended quantity is 3 to 8% of feed.  If the was water injection quantity is not enough due to wash water injection pump problem or other problems, Hydro Cracker Unibon load/feed must be reduced so that the required wash water quantity 3-8% of feed can be fulfilled to avoid any negative impacts mentioned above.  If the wash water injection cannot be supplied to the unit due to wash water injection pump problem or other problems, as per the Standard Operating Procedure of Hydro Cracker Unibon, the unit must be shutdown.

The problem which was often happened was the low performance of wash water injection pumps.  There were 3 wash water injection pumps, which was one of them in operation stand by while the other 2 pumps were in operation to supply wash water to fresh feed system and to recycle feed system.  This low performance of wash water injection pumps often produced high main fractionation column bottom product which had low value, produced less middle distillate yield, and even they often forced the unit load to be reduced or shutdown.

The Quality Control Project team’s target is to troubleshoot the Hydrocracker Unibon Main Fractionation Column High Bottom Yield.

2.  Title

The title chose by the Quality Control Project team is “Troubleshoot the Hydrocracker Unibon Main Fractionation Column High Bottom Yield”.

The reason to choose this title was because it could reduce one of the Hydrocracker Unibon refining and production potential loss by reducing the main fractionation column high bottom yield, so that refining target and middle distillate yield target could be achieved.

3.  Organization Chart

Organization Chart PKM Reaktor

Figure 1.  Organization Chart of Quality Control Project Team

4. Time Schedule

Table 1. Time Schedule of Quality Control Project Team

Time Schedule PKM Reaktor-Rev1

5.  Facts and Findings

Some facts and findings related to the problem are as follows:

5.1. Hydro Cracker Unibon Main Fractionation Column Bottom Product to Off Spec Tank during Wash Water Injection Pump Failure (3 Months Data)

Usually, during normal operation, Hydro Cracker Unibon main fractionation column bottom product can be sent to Diesel product tank, because the quality is so close to Diesel and the quantity is not so high.  Nevertheless, during wash water injection pump failure, the quantity becomes huge and the quality is also reduced, so that it must be sent to off spec tank.

The data of Hydro Cracker Unibon Main Fractionation Column Bottom Product to Off Spec Tank during Wash Water Injection Pump Failure can be seen as follows:

Table 2. HCU Bottom Product to Off Spec Tank before Project Implementation (3 Months Operation Data)

No.

Train

Bottom   Product

M3

Bbl

1.

Hydro Cracker   Unibon Train 1

5712.18

35925.61

2.

Hydro Cracker   Unibon Train 2

8100.15

50944.27

Total

13812.33

86869.88

HCU Bottom Product to Slop Tank before Project

Figure 2.  Histogram of HCU Bottom Product Before Project (3 Months Operation Data)

5.2. Wash Water Temperature Data (2 months Data)

Wash water temperature data which was taken for 2 months (manually, because there is no temperature indicator in DCS), totally 60 data, classified into some ranges can be seen as follows:

Table 3. Wash Water Temperature Data (Before Project)

No.

Temperature    Range,   o C

Frequency

1.

58-61

2

2.

62-65

3

3.

66-69

13

4.

70-73

26

5.

74-77

8

6.

78-81

8

If the above table is plotted as histogram, it can be seen as follows: Wash Water Temperature (PKM Reaktor)

Figure 3.  Histogram of Wash Water Temperature Data (Before Project)

From above figure, it can be seen that average wash water temperature is 71.4 oC, which is far away above maximum design temperature 54 oC.

5.3. Wash Water Injection Pump Failure Data (1 year Data) Wash water injection pump failure data can be seen as follows:

Table 4. Wash Water Injection Pump Failure Data Based on Pump Failure

(Before Project)

No.

Pump

Failure Type

Gland Packing

Gear Box

Crank Case

Others

1.

Train 1 P-1 A

89

2

2

18

2.

Train 1 P-1B

91

2

2

9

3.

Train 1 P-1C

13

2

0

2

4.

Train 2 P-1A

48

5

2

5

5.

Train 2 P-1B

63

0

1

4

6.

Train 2 P-1C

11

1

0

5

Total

315

12

7

43

Note : A is for fresh feed section, B is for recycle feed section, and C is for common spare.

If the above wash water injection pump failure data is classified in failure type instead of in failed pump, it can be seen as follows:

Table 5. Wash Water Injection Pump Failure Data Based on Failure Type

(Before Project)

No.

Failure Type

Total

Cumulative

%

% Cumulative

1.

Gland   Packing

315

315

83.8

83.8

2.

Others

43

358

11.4

95.2

3.

Gear   Box

12

370

3.2

98.4

4.

Crank   Case

6

376

1.6

100

If the above table is plotted as pareto chart in a month basis (divided by 12), it can be seen as follows:

Pareto Chart of Wash Water Injection Pump Failure (PKM Reaktor)

Figure 4.  Pareto Chart of Wash Water Injection Pump Failure (Before Project)

From above table and above pareto chart, it can be seen that the pump failure caused by gland packing failure contributed 315 times in a year or 26.25 times in a month.  Maintenance cost of gland packing failure is US$ 230.  Therefore in a year, maintenance cost of gland packing failure is US$ 72450.

6.  Problem Identification and Root Cause Analysis

To identify problem causes, fishbone diagram (or also called Ishikawa diagram or Fishikawa diagram or cause-and-effect diagram) is used.  The fishbone diagram for the problem is as follows:

Fishbone Diagram for Gland Packing Failure

Figure 5.  Fishbone Diagram for Gland Packing Failure

Based on above fishbone diagram, some possible root cause of the gland packing failure and their impacts are as follows:

Table 6. Possible Root Causes of Gland Packing Failure and Its Impact

No.

Root   Cause

Impact

1.

MANAGEMENT: Less fund allocation for   maintenance. Equipment maintenance has less   priority à Low equipment reliability (surface condenser low   performance) à High temperature of wash water.

2.

MATERIALS: Surface condenser low   performance à Higher temperature of wash water. Improper condition for gland packing   (more severe condition compared to its design).  From figure 1, actual average wash water   temperature is 71.4 oC, which is far away above maximum design   temperature 54 oC.

3.

EQUIPMENT: Plunger attrition,   scratch, pitting.
  • Gap between   gland packing and plunger which causes leak; once it is leak, the leak will   immediately be bigger and bigger.
  • Gland packing   receives high pressure from discharge.

From Table 6 and Figure 5, it is found that plunger attrition, scratch, and pitting were only happened very rare (less than 11.4%; as a failure type mentioned in that table and figure, it is classified as “others”).

Therefore, the Quality Control Project Team agreed to troubleshoot “High  Temperature of Wash Water”.

7.  Troubleshooting Alternatives

Table 7. Troubleshooting Alternatives and Their Total Benefits

No.

Troubleshooting Alternatives

Total Investment (I), US$

Total Revenue/month (R), US$

Total Benefit

(R/I)

1.

Improve   Surface Condenser by Increasing its spare part stocks.

657850

7698171

1.17

2.

Improve   Surface Condenser by replacing 5 out of 10 turbine to motor as its driver.

600269

8629792

1.44

3.

Replace   wash water by demineralized water that temperature is acceptable within wash   water injection pump specification.

36968

7698171

20.82

4.

Reduce   wash water temperature by utilizing an idle heat exchanger which was designed   to be used during in-situ regeneration.    The heat exchanger has already been idle for 17 years due to ex-situ regeneration was decided instead of in-situ regeneration.

12323

7698171

62.47

Note:

1 = potential revenue from avoiding diesel product to be routed to slop tank.

2 = potential revenue from avoiding diesel product to be routed to slop tank and from cost saving of operational and maintenance cost after changing the driver from turbine to motor.

From above table (Table 7), it can be made into histogram, as follows:

Troubleshooting Alternatives & the Total Benefits (PKM Reaktor)

Figure 6.  Histogram of Troubleshooting Alternatives and Their Total Benefits

From above histogram (Figure 6), it can be clearly concluded that Alternative 4 will give highest total benefit compared to other alternatives.  Therefore the Quality Control Project Team chose Alternative 4 to increase the wash water injection pump reliability, which has some benefits as follows:

  • Utilization of an idle heat exchanger.
  • Simple procurement of materials.
  • Low cost.

8.  Equipment Design Data

Some data of equipment related to the Project are as follows:

8.1. Wash Water Injection Pump

Wash water injection to REAC (Reactor Effluent Air Cooler) uses plunger pumps.  The design data of the wash water injection pump is as follows:

Table 8. WashWater Injection Pump Design Data

No.

Parameter

Unit of Measurement (UOM)

Design Data

1.

Capacity   (normal)

m3/hour

5.9

2.

Capacity   (design)

m3/hour

7.4

3.

Suction   pressure

kg/cm2g

0

4.

Discharge   pressure

kg/cm2g

179.5

5.

Service   Fluid

Water

6.

Temperature,

oC

54

7.

Driving   Force

Motor

Motor

8.

Speed

Rpm

1500

8.2. Heat Exchanger to be used in the Project

Heat Exchanger to be used in the Project is a heat exchanger designed for being used in in-situ catalyst regeneration.  The heat exchanger has already not been used for 17 years due to economical reason (it was concluded to be economical to do ex-situ catalyst regeneration instead of in-situ catalyst regeneration).  The design data of the heat exchanger is as follows:

Table 9. Wash Water Injection Pump Design Data

Parameter

Shell

Tube

Before Project

After Project

Before Project

After Project

Pressure, kg/cm2g

11.4

4.82

8.5

2.91

Temperature, oC

150

42-61

30

30

Service Fluid

Gas

Cold condensate

Sea water

Cooling water

9. Target Determination

Based on the Quality Control Project Team brainstorming, the targets of the Quality Control Project are as follows:

Table 10. Target of Quality Control Project

No.

Parameter

Before Project

Target after Project

Remark

1.

Wash   water temperature

>   70oC

54oC

As   per the wash water injection pump specification.

2.

Gland   packing failure

26.25   times/month

40%   of before the project implementation = 10.5

Times/month

Gland   packing failure is also caused by other factors.  Therefore based on the team brainstorming,   the target 40% is reasonable.

10.  Improvement Planning

Improvement planning can be seen in the below table:

Table 11. Improvement Planning

Improvement   Planning

Action

Target

Leader

Evaluation

Process Engineer

June 2003

Process Engineer

Drawing

Process Engineer,

Maintenance,

Operation,

Inspection

June 2003

Process Engineer

Hazops   (Hazard & Operability Study)

Process Engineer,

Operation,   Maintenance

June 2003

Process Engineer

Work Order Issuing

Operation

July 2003

Operation

Heat   Exchanger repair/re-tubing/tube bundle cleaning

Workshop,

Inspection

September

2003

Inspection

On   stream hot tapping

Maintenance,

Workshop,

Inspection

September

2003

Maintenance

Wash   water line and cooling water line fabrication

Maintenance,

Workshop

January

2004

Workshop

Commissioning

Operation,

Maintenance,

Inspection

January

2004

Operation

11.  Implementation

Actual implementation of the project can be seen as follows:

Table 12. Improvement Planning

Improvement   Planning

Action

Target

Leader

Evaluation

Process Engineer

June 2003

Process Engineer

Drawing

Process Engineer,

Maintenance,

Operation,

Inspection

June 2003

Process Engineer

Hazops   (Hazard & Operability Study)

Process Engineer,

Operation,   Maintenance

August 2003

Process Engineer

Work Order Issuing

Operation

September 2003

Operation

Heat   Exchanger repair/re-tubing/tube bundle cleaning

Workshop,

Inspection

December

2003

Inspection

On   stream hot tapping

Maintenance,

Workshop,

Inspection

December

2003

Maintenance

Wash   water line and cooling water line fabrication

Maintenance,

Workshop

December 2003 to   January

2004

Workshop

Commissioning

Operation,

Maintenance,

Inspection

January

2004

Operation

12.  Evaluation After the Project Implementation

12.1. Wash Water Injection Pump Failure after the Project Implementation

Wash water injection pump failure after the Project Implementation can be seen as follows:

Table 13. Wash Water Injection Pump Failure Data Based on Failure Type for 2 Months (After Project)

No.

Pompa

Kerusakan

Gland Packing

Gear box

Crankcase

Lain-lain

1.

211   PM-5A

11

0

0

2

2.

211   PM-5B

1

1

0

1

3.

211   PM-6

2

0

0

2

4.

212   PM-5A

6

0

0

4

5.

212   PM-5B

0

0

0

0

6.

212   PM-6

2

0

0

2

Total

22

1

0

11

If the above table is plotted as pareto chart in a month basis (divided by 2), it can be seen as follows:

Pareto Chart of Wash Water Injection Pump Failure (After Project)-PKM Reaktor

Figure 7.  Pareto Chart of Wash Water Injection Pump Failure (After Project)

From above table and above pareto chart, it can be seen that the pump failure caused by gland packing failure has been reduced from 26.25 times (before project) to 11 times (after project) in a month.  In consequence of that reduction, the maintenance cost of gland packing failure can be reduced from US$ 72450 to US$ 30360.

12.2. Wash Water Temperature after the Project Implementation

Wash water temperature data after the Project Implementation can be seen as follows:

Table 14. WashWater Temperature Data (After Project)

No.

Temperature    Range,   o C

Frequency

1.

42-45

2

2.

46-49

5

3.

50-53

15

4.

54-57

26

5.

58-61

12

If the above table is plotted as histogram, it can be seen as follows:

Wash Water Temperature after the Project Implementation (PKM Reaktor)

Figure 8.  Histogram of Wash Water Temperature Data (After Project)

From above table and above histogram, it can be seen that the temperature of wash water has been reduced from 71.4 oC (before project) to 53.5 oC (after project).

12.3. Hydro Cracker Unibon Main Fractionation Column Bottom Product to Off Spec Tank during Wash Water Injection Pump Failure

The data of Hydro Cracker Unibon Main Fractionation Column Bottom Product to Off Spec Tank during Wash Water Injection Pump Failure (after Project Implementation) can be seen as follows:

Table 15. HCU Bottom Product to Off Spec Tank after Project Implementation (3 Months Operation Data)

No.

Train

Bottom   Product

M3

Bbl

1.

Hydro Cracker   Unibon Train 1

860.45

5411.63

2.

Hydro Cracker   Unibon Train 2

295.28

1857.1

Total

115.73

7268.73

HCU Bottom  Product to Slop after Project (PKM Reaktor)

Figure 9.  Histogram of HCU Bottom Product after Project

(3 Months Operation Data)

From above table and figure, it can be seen that HCU Bottom Product to Off Spec Tank has been reduced from 86869.88 bbl (before Project Implementation) to 7268.73 bbl (after Project Implementation) based on 3 months operation data.

Summary (PKM Reaktor)

14. Conclusion

Quality Control Project should be a project which gives added value to the company.  This Quality Control Project can clearly give added value to the company as follows:

  1. Contribute the potential profit (by reducing potential loss) US$ 795,479/month.
  2. Reduce wash water temperature to be as per requirement, 53.5oC (versus design = 54oC).
  3. Utilize an idle heat exchanger.
  4. Implement the project without stopping the plant (done by on-stream hot tapping).

Based on Kaizen (Continuous Improvement) analysis (QCSDM), the Quality Control Project contribute some added values to the company, as follows:

Table 16. Kaizen (Continuous Improvement) Analysis (QCSDM)

Kaizen

Item

Description

Impact of the Project

Q

Quality By reducing the   wash water injection pump gland packing failure, HCU bottom product to slop   can be reduced and it can be routed as diesel product.

C

Cost By reducing the   wash water injection pump gland packing failure, maintenance cost can be reduced   so that HCU profit margin can be increased.

S

Safety
  • By   reducing the wash water injection pump gland packing failure, the risk during   the wash water injection pump gland packing replacement can be reduced (the   pump pressure is around 170 kg/cm2g).
  • By   reducing the wash water temperature, higher temperature spreading to the   environment and the employees can be avoided.

D

Delivery By increasing   diesel product, the company can supply more diesel to customer.

M

Moral
  • By   reducing the wash water injection pump gland packing failure, maintenance   personnel can be more relax.
  • By   increasing diesel product and reducing maintenance cost, the profit margin   can be increased and the company can give more yearly bonus to the employees.
  • By   reducing the wash water temperature, higher temperature spreading to the   environment and the workers can be avoided.
  • Increasing   ownership and togetherness among departments within the company by solving   the company problems together to achieve the company target/goal.

Fuel Consumption Reduction: Which is much more economical, Producing Medium Pressure Steam or Reducing Fuel Consumption?

by Adhi Budhiarto

1.  Background

In a Vacuum Distillation Unit (VDU), HVGO (Heavy Vacuum Gas Oil) product is used as heating media of a heat exchanger, which heats Boiler Feed Water (BFW) to produce Medium Pressure Steam (MP Steam).  Then, HVGO is routed to pre-heater to be used as heating media to increase VDU feed temperature before being charged to Charge Heater.  As per design flow scheme, no HVGO is bypassed from HVGO/BFW Heat Exchanger (Pre-heater); all HVGO is routed to the Heat Exchanger to produce MP Steam.  Nevertheless, to reduce fuel consumption of Charge Heater, there is a proposal to bypass some HVGO so that it can increase the inlet temperature of Charge Heater.  However, this scheme on the other hand will also reduce MP Steam production.  Then, which is much more economical, producing MP Steam or reducing the fuel consumption?

2.  Objectives

2.1. Do technical study on the proposal “Reducing Charge Heater Fuel Consumption by Bypassing some HVGO from HVGO/BFW Heat Exchanger (Pre-heater) which can Increase Charge Heater Inlet Temperature with the Compensation of Reducing Medium Pressure Steam Production”

2.2. Do economical evaluation on the proposal if it is technically feasible.

3.  Description

HVU MP Steam or Fuel Consumption Reduction (Case Study 2)

Figure 2Case-2 Improvement Study Scope of Study

HVGO (Heavy Vacuum Gas Oil) from Vacuum Distillation Column is taken from the draw off/collector tray, pumped to HVGO/BFW Heat Exchanger (E-1).  In E-1, HVGO is utilized as its heating media to increase circulated BFW (Boiler Feed Water) temperature to produce MP Steam (Medium Pressure Steam).  Then, the stream is divided into 3 separate streams, 1) HVGO/Long Residue (from Tank) Heat Exchanger (E-2), 2) HVGO/Total Feed Heat Exchanger (E-3), and 3) HVGO/Make up BFW Heat Exchanger (E-4).

In E-2, HVGO is utilized as its heating media to increase temperature of Long Residue feed from tank before being routed to surge drum (V-3), combined with Long Residue feed from CDU (Crude Distillation Unit).  In E-3, HVGO is utilized as its heating media to increase temperature of Total Feed from V-3, before being routed to Total Feed/Vacuum Bottom Heat Exchanger (E-5).  In E-4, HVGO is utilized as its heating media to increase temperature of Makeup BFW, before being routed to Steam Drum (V-2).

HVGO streams from E-2, E-3, and E-4 are combined and routed to HVGO Air Cooler (E-6).  Then this stream is divided into 2 streams, 1) stream to be returned back to Vacuum Distillation Column as reflux, 2) stream to be taken as HVGO product, pumped by HVGO product pump (P-8) to HVGO cooler (E-8) and finally routed to HCU (Hydro Cracker Unibon) or to HVGO Storage Tank.

Total Feed from E-5 is divided into 2 streams, to charge heater H-1 A and charge heater H-1 B.  From these charge heaters, the feed is then combined and routed to Vacuum Distillation Column.  In this simulation, there are 4 dummy heat exchangers created, 1) Dummy H-1 A, 2) Dummy H-1 B, 3) Dummy H-1 A Out, and 4) Dummy H-1 B Out.  They are created in the simulation because there is a little difference between outlet temperature of upstream equipment and downstream equipment (between E-5 outlet and H-1 A/B inlet and between H-1 A/B outlet and Temperature Indicators near Vacuum Distillation Column.

Normally, all HVGO from P-1 is routed through E-1, without bypass.  To reduce charge heater (H-1 A/B) fuel consumption, there is an idea to some HVGO from P-1 to E-1 bypass line.  It will keep HVGO temperature higher so that E-3 inlet temperature will be higher.  By having higher E-3 HVGO inlet temperature as E-3 heating media, E-5 Total Feed outlet temperature will also be higher which will increase inlet temperature of H-1 A/B.  By having higher inlet temperature of H-1 A/B with the same outlet temperature of H-1 A/B, H-1 A/B fuel consumption can be reduced.

Nevertheless, this idea will reduce MP Steam production as HVGO as heating media in E-1 is utilized to produce MP Steam.  Therefore optimization study must be done to know whether this idea is technically feasible or not and whether it can be more economical or not.

4.  Method of Study

4.1. Assumption

Condition/performance of all equipment is assumed to be the same with their condition/performance in the last performance test (which was conducted only a few months before).

4.2. Feasibility Study

4.2.1. Build Simulation Model by Simulation Software

Data which is used to build simulation model is taken from the last unit performance test.  In this simulation model, all overall heat transfer coefficients (U) of heat exchangers and air cooler are calculated by simulation software by using performance test data inputs.  All HVGO from P-1 is all routed through E-1; E-1 bypass flow is zero.

4.2.2. Do Simulation by Simulation Software

Simulation is done by optimizing HVGO bypass flow of E-1 by 2 constraint limitation: 1) temperature of HVGO to storage tank and 2) temperature of HVGO reflux to Vacuum Distillation Column.  All overall heat transfer coefficients (U) of all heat exchangers and air cooler are used as inputs (not as output), which is the same with U calculated from simulation model.  H-1 A/B duty and MP Steam production will be calculated by simulation software (as outputs).

4.3.3. Economical Study

Economical Study is done by calculating economizing on fuel consumption of H-1 A/B and calculating financial loss caused by producing less MP Steam.  Financial loss of MP Steam will also include the possibility of having let down steam from HP Steam (High Pressure Steam) to MP Steam to cover the whole refinery needs on MP Steam, because MP Steam from VDU (Vacuum Distillation Unit) is exported to Utility Department to be used for the whole refinery complex.

5.  Design Data & Calculation

5.1. Design Data

Some important design data which must be considered to judge the o feasibility are as follows:

Table I.

Important Design and Actual Data to be Considered

for Feasibility Judgment

No.

Parameter

Design

Actual3)

H-1

1.

H-1 A Combined   Inlet Temperature, oC

274

253.54

2.

H-1 B Combined   Inlet Temperature, oC

250.68

3.

H-1 A Combined   Outlet Temperature, oC

421

415.18

4.

H-1 B Combined   Outlet Temperature, oC

411.12

5.

H-1 A Heat Duty, 106   kcal/hour

37.97

32.74

6.

H-1 B Heat Duty, 106   kcal/hour

33.74

P-5

7.

P-5 Pumping   temperature, oC

135

140.21

8.

P-5 Casing Maximum Temperature,   oC

450

9.

Specific Gravity of   P-5 Fluid at PT

0.799

0.813

10.

Viscosity of P-5 fluid   at PT, cP

3.8

1.85

11.

Vapor Pressure of   P-5 Fluid at PT, kg/cm2A

< 0.1

0.027

V-1

12.

Flash Zone   Temperature, oC

410

401.33

13.

HVGO Reflux Temperature (E-6 Outlet Temperature), oC

135

140.2

V-2

14.

Medium Pressure   Steam Production, Ton/hour

74.785

67.99

HVGO Storage Tank

15.

Maximum Storage   Tank Temperature, oC

80

77.51)

16.

Vapor Pressure at   37.8oC, kg/cm2A

<<0.07

0.033

Steam Header

17.

Total   Flow of Steam Let Down (HP Steam downgrade to MP Steam), Ton/hour

63.842)

Note :

1) Data shows that HVGO Storage Tank average temperature = 77.5oC when E-7 HVGO outlet temperature = 112.07oC (∆T = 34.57oC).

2) Average data during normal operation (before modification implementation).

3) Simulation software output using last performance test data.

5.2. Feasibility Study

Considering design and actual data shown in Table I, process/technical evaluation to the proposal is done with a limitation of HVGO storage tank temperature (it must be < 80 oC, which is the storage tank design maximum temperature) and also by considering other parameters like HVGO reflux temperature (which will give effect to the VDU product quality and quantity), HVGO product pump (P-5) pumping temperature, P-5 fluid specific gravity, P-5 fluid viscosity, P-5 fluid vapor pressure, H-1 COT (Combined Outlet Temperature), and H-1 duty.

Based on operational experience, HVGO storage tank temperature will reach its design maximum temperature (80 oC) when E-7 shell HVGO outlet temperature is 114.57 oC (based on a field data that HVGO storage tank average temperature = 77.5 oC when E-7 HVGO outlet average temperature  = 112.07oC (∆T = 34.57oC)).
Nevertheless, to give enough safety factor, in the simulation, E-7 shell
outlet HVGO temperature is set to 110 oC at maximum (safety factor = 5%).

Besides that, another limitation considered in the simulation is HVGO reflux temperature, because HVGO reflux temperature will give impact to HVGO draw off temperature.  Based on operational experience, 5 oC higher on HVGO draw off temperature will not give impact to HVGO product quality (and even it will give more HVGO product quantity).  Therefore,  HVGO reflux temperature (E-6 outlet temperature) is set 145 oC (5 oC or 3.6% higher than actual normal temperature).

After the proposal is simulated by simulation software, the complete results are as follows:

Table II.
Simulation Software Results

No.

Parameter

Simulation Results

Design Data

Actual

Data2)

V-1

1.

HVGO draw off flow,   m3/hour

906.14

1031

906.14

2.

HVGO draw off   temperature, oC

271.71

288

271.71

3.

V-1 flash zone temperature, oC

401.33

410

401.33

4.

HVGO reflux temperature (E-6 outlet temperature), oC

145.64

135

140.2

E-1

5.

HVGO Flow through   E-1 shell, m3/hour

626,14

838,9

626,14

6.

HVGO Flow through   E-1 shell bypass, m3/hour

280

0

0

H-1

7.

H-1 A Combined   Inlet Temp., oC

258,3

274

253,54

8.

H-1 B Combined   Inlet Temp., oC

255,46

250,68

9.

H-1 A Combined   Outlet Temp., oC

415,18

421

415,18

10.

H-1 B Combined   Outlet Temp., oC

411,12

411,12

11.

H-1 A Duty, 106 kcal/hour

31,858

37,97

32,74

12.

H-1 B Duty, 106   kcal/hour

32,826

33,74

P-5

13.

P-5 pumping   temperature, oC

145,65

135

140,21

15.

P-5 casing maximum   temp., oC

450

16.

P-5 Fluid Specific   Gravity at PT

0,809

0,799

0,813

17.

P-5 Fluid Viscosity   at PT, cP

1,64

3,8

1,85

18.

P-5 fluid vapor   pressure at PT, kg/cm2a

0,035

< 0,1

0,026

V-1

19.

MP Steam product, T/hour

53,818

74,785

67,99

HVGO Storage Tank

20.

E-7 outlet   temperature, oC

110,06

80

104,26

21.

Storage Tank temp. prediction, oC

75,491

69,691)

22.

HVGO product vapor   pressure at 37,8oC, kg/cm2a

0,033

<<0,07

0,033

Note :

1) Storage tank temperature prediction is assumed based on a field data that HVGO storage tank average temperature = 77.5 oC when E-7 HVGO outlet average temperature  = 112.07oC (∆T = 34.57oC).

2) Simulation software output using last performance test data.

From above simulation software results, it can be concluded that the proposal “Reducing Charge Heater Fuel Consumption by Bypassing some HVGO from HVGO/BFW Heat Exchanger (Pre-heater) which can Increase Charge Heater Inlet Temperature with the Compensation of Reducing Medium Pressure Steam Production” is technically feasible.  The unit MP Steam consumption, which is around 25 Ton/hour, can still be provided.  Nevertheless, MP Steam export product will be reduced.  MP Steam production will be reduced from 68 Ton/hour to 54 Ton/hour (14 Ton/hour
reduction).

5.3. Economical Study

Economical Study is done by calculating cost saving of H-1 fuel consumption and total loss of MP Steam product reduction.  Total loss of MP Steam product reduction includes the consequence to down grade HP Steam product to MP Steam product from Let Down System (because the refinery/complex MP Steam product supply and demand are already balance; while HP Steam is still possible to be increased).

Table III.

Economical Study Results

No.

Parameter

Nilai

1.

H-1 duty   reduction, 106 kcal/hour 1)

1.796

2.

H-1 fuel   consumption saving,TSRF/hour2)

0.1833

3.

LHV of fuel   oil, kcal/kg3)

10049.6

4.

H-1 fuel   consumption saving, kg/hour4)

178.75

5.

Fuel Oil Specific   Gravity

0.899

6.

H-1 fuel   consumption saving, Bbl/hour

1.1762

7.

Fuel Oil price,   US$/Bbl 5)

31.34

H-1 fuel   consumption cost saving, US$/hour

36.86

8.

H-1   atomizing steam consumption, kg/kg of fuel oil

0.3

10.

H-1   atomizing steam consumption saving, kg/hour

53.625

11.

HP Steam   price (2004 data; own use), US$/ton

11.07

12.

MP Steam   price, US$/ton6)

9.3

H-1   atomizing steam cost saving, US$/hour

0.5

13.

MP Steam   product reduction, Ton/hour

14.172

14.

Loss caused by MP Steam product reduction, US$/hour

131.8

15.

Loss caused   by refinery/complex HP Steam product increase to supply let down system, US$/hour   7)

156.9

Kerugian, US$/hour

288.7

Total   Loss, US$/hour

251.3

Note :

1) H-1 duty reduction = H-1 A duty reduction + H-1 B duty reduction.

2) TSRF = H-1 duty reduction/9800000.

3) LHV of Fuel Oil = (11088 – 2100 x ρ152 + 757 x ρ15) x (1 – water fraction – ash fraction – sulphur fraction) + 2450 x sulphur fraction.

4) Fuel Oil consumption saving = TSRF x 9800 x 1000 / LHV of fuel oil

5) Fuel Oil average price (January 2004 to March 2005).

6) Because there is no MP Steam data in the company finance department which can be used, then MP Steam price is calculated based on its caloric value.  HP Steam and MP Steam heat capacity are 10.554 and 8.8631 kcal/kgmol/oC, respectively.  Therefore MP Steam price = 8.8631 / 10.554 x US$ 11.07 = US$ 9.3.

7) Because MP Steam supply and demand are already balance and there is still possibility to increase HP Steam production which is later possible to be down grade to MP Steam through Let Down System, then HP Steam which will be down grade to MP Steam is assumed to be the same with MP Steam product reduction.

6.  Conclusion

Based on above economical study, it can be concluded that the proposal “Reducing Charge Heater Fuel Consumption by Bypassing some HVGO from HVGO/BFW Heat Exchanger (Pre-heater) which can Increase Charge Heater Inlet Temperature with the Compensation of Reducing Medium Pressure Steam Production” is NOT ECONOMICAL even though it is technically feasible, because it results to potential loss of US$ 251.3/hour.

Fuel Consumption Reduction in Distillate Hydro Treating Unit (DHDT) by Increasing Feed Temperature

by Adhi Budhiarto

1.    Background

In a refinery, fuel consumption is one of high operating costs.  As one of refinery processing units, DHDT also finds fuel consumption as one of its high operating costs.  Therefore, to optimize fuel consumption of Fired Heater/Furnace of DHDT is one of important actions to optimize the unit total operating cost.

2.    Objectives

Objectives of this study are as follows:

2.1. Do technical study on some possible manners to optimize fuel consumption of Fired Heater/Furnace of DHDT by increasing its feed temperature, such as a) Stop 1 out of 2 air coolers at upstream unit (Delayed Coking Unit/DCU) which cool down DHDT feed temperature before being routed to DHDT Battery Limit, while DCU trim cooler is still operated, b) Stop all 2 air coolers of DCU, while DCU trim cooler is still operated, and c) Stop DCU trim cooler, while all 2 air coolers are operated.

2.2. Do economical evaluation on each proposal which is technically feasible.

3.    Description

DHDT Fuel Consumption Reduction

Figure 1.  Case-1 Improvement Study Scope of Study

DHDT is a small unit to process feed, LCGO from DCU (84 m3/hour or 12.7 MBSD), to produce Naphtha, Light Kerosene, and Heavy Kerosene and to treat product so that the products have lower sulphur content and nitrogen content, and Heavy Kerosene has lower Bromine Number.  Nitrogen content in the product can impact to the product color stability.  It is very important for Light Kerosene and Heavy Kerosene, because Light Kerosene is able to be one of Jet Fuel blending components and Heavy Kerosene is one of Diesel blending components.  If Light Kerosene or Heavy Kerosene color stability is not good, it will promote to give color unstability to the whole Jet Fuel or Diesel where they are blending in.  Bromine Number is the number indicating the degree of unsaturation (olefin content).

LCGO (Light Coker Gas Oil) product produced in DCU (Delayed Coking Unit) before being routed to DHDT (Distillate Hydro Treating) or to Storage Tank is routed to 2 units of Air Cooler (E-1 (DCU)) and 1 unit of Heat Exchanger (E-2 (DCU)).  Usually, LCGO is routed directly to DHDT, except during DHDT shutdown, it will be routed to Storage Tank instead of to DHDT.  This scheme is an opportunity to increase DHDT feed temperature, because the Process Engineer sees that the purpose of having cooling system in the LCGO product is because it will have to be routed to Storage Tank which has lower design temperature compared to design temperature of DHDT equipment.

In DHDT, LCGO is routed to Surge Drum (V-1 (DHDT)), then it is pumped by P-1 (DHDT) to E-3 (DHDT).  Before being routed to E-3 (DHDT), LCGO is mixed with Recycle Gas (RG) from Recycle Gas Compressor (RG Comp. (DHDT)), which is combined with Make up Gas (MUG) from Make up Gas Compressor (MUG Comp. (DHDT)).

From E-3 (DHDT), mixed Feed (LCGO and Recycle Gas) is routed to Fired Heater/Furnace (H-1 (DHDT)) to further increase its temperature before being routed to 2 units of Reactors (R-1 (DHDT) and R-2 (DHDT)).  In Reactors, the Feed experiences desulphurization and denitrification processes to remove sulphur content and nitrogen content in the Feed.

4.    Method of Study

4.1. Assumption:

  • Condition/performance of all equipment is assumed to be the same with their condition/performance in the last performance test (which was conducted only a few months before).
  • To simplify the calculation, reactor effluent assay is assumed to be the same with LCGO feed assay (because only desulphurization and denitrification are took place in the reactor; no cracking reaction is took place).

4.2. Feasibility Study

4.2.a. Build Simulation Model by Simulation Software

Data which is used to build simulation model is taken from the last unit performance test.  In this simulation model, all overall heat transfer coefficients (U) of air cooler and heat exchanger are calculated by simulation software by using performance test data inputs.  All LCGO product flows from E-1 (DCU) to E-2 (DCU); E-2 (DCU) bypass flow is zero.

4.2.b. Do Simulation by Simulation Software for All Improvement Alternatives

All 3 improvement alternatives are made into simulation, as follows:

  • Alternative 1: Simulation with 1 Unit out of 2 Units of Air Cooler E-1 (DCU) is not Operated

In this simulation, U value of E-1 (DHDT), calculated from last performance test data, is taken as an input (not as an output), which is half of calculated U from simulation model (because only 1 unit of air cooler is operated), so that E-1 (DHDT) outlet temperature is calculated by simulation software.  All LCGO product flows from E-1 (DCU) to E-2 (DCU); E-2 (DCU) bypass flow is zero.  U values of E-2 (DCU), E-3 (DHDT), and E-4 (DHDT), calculated from last performance test data, are taken as inputs (not as outputs), which are the same with U values from simulation model, so that their outlet temperatures are calculated by Simulation Software.

  • Alternative 2: Simulation with All 2 Units of Air Cooler E-1 (DCU) is not Operated

Like in Alternative 1, in this simulation, U value of E-1 (DHDT) is also used as an input (not as an output), which is zero, because no heat transfer due to all 2 Units of E-1 (DHDT) are not operated (so that E-1 (DHDT) outlet temperature is the same with its inlet temperature).  All LCGO product flows from E-1 (DCU) to E-2 (DCU); E-2 (DCU) bypass flow is zero.  U values of E-2 (DCU), E-3 (DHDT), and E-4 (DHDT), calculated from last performance test data, are taken as inputs (not as outputs), which are the same with U values from simulation model, so that their outlet temperatures are calculated by simulation software.

  • Alternative 3: Simulation with All 2 Units of Air Cooler E-1 (DCU) are Operated, but Heat Exchanger E-2 (DCU) is not Operated (Bypass)

Like in Alternative 1 & 2, in this simulation, U value of E-1 (DHDT), calculated from last performance test data, is taken as an input (not as an output), which is the same U value as it is calculated in the simulation model, so that E-1 (DHDT) outlet temperature is calculated by simulation software.  All LCGO product flows from E-1 (DCU) through E-2 (DCU) bypass flow (E-2 (DCU) is not operated).  U values of E-3 (DHDT) and E-4 (DHDT), calculated from last performance test data, are taken as inputs (not as outputs), which are the same with U values from simulation model, so that their outlet temperatures are calculated by simulation software.

4.3. Economical Study

Economical Study will be done for all improvement alternatives which are technically feasible.

5.    Design Data & Calculation

5.1. Design Data

Some important design data which must be considered to judge the improvement alternative feasibility are as follows:

Table I.

Important Design Data to be Considered for Feasibility Judgment

No.

Parameter

Design

Actual1)

V-1 (DHDT)

1.

V-1   (DHDT) inlet temperature, oC

38

50

2.

V-1   (DHDT) operating temperature, oC

38

50

3.

V-1 (DHDT) mechanical design temperature,   oC

120

P-1 (DHDT)

4.

P-1 (DHDT) pumping temperature, oC

38

50

5.

P-1 (DHDT) mechanical seal maximum temperature,   oC

250

6.

P-1 (DHDT) casing maximum temperature,   oC

175

52

7.

P-1 (DHDT) fluid specific gravity at   PT

0.79

0.7896

8.

P-1 (DHDT) fluid viscosity at PT, cP

1.5

1.2728

9.

P-1 (DHDT) fluid vapor pressure at   PT, kg/cm2a

<1

0.04

H-1 (DHDT)

10.

H-1 (DHDT) combined inlet   temperature, oC

336

285.7

11.

H-1 (DHDT) combined outlet   temperature, oC

357

295

12.

H-1 (DHDT) duty, 106   kcal/hour

3.28

0.663

13.

LCGO storage tank maximum   temperature, oC

55

2)

Note: 1) Simulation software output using last performance test data.

2) Actually, during DHDT normal operation, no LCGO product is routed to storage

tank, all LCGO product is routed from DCU to DHDT.  Nevertheless, during

DHDT shutdown, LCGO will be routed to LCGO storage tank, instead of being

routed to DHDT.

Based on above data, the most important design data which must be considered is V-1 (DHDT) mechanical design temperature, which is 120 oC.  Off course all other parameters must also be considered, such as P-1 (DHDT) pumping temperature, P-1 (DHDT) fluid specific gravity, P-1 (DHDT) fluid viscosity, P-1 (DHDT) fluid vapor pressure, H-1 (DHDT) combined outlet temperature, and H-1 (DHDT) duty.

To give enough safety factor, in the feasibility study, DHDT inlet temperature is limited to be around 90 oC, compared to V-1 (DHDT) mechanical design temperature 120 oC (safety factor = 33%).  It is already more than enough to economize on fired heater fuel consumption, because the feed inlet temperature can be increased 40 oC from 50 oC to 90 oC.

5.2. Feasibility Study

After simulation is done by following method of study mentioned in VIII.3.4.2.b. for all 3 improvement alternatives, the results are as follows:

Table IISimulation Software Results

No.

Parameter

E-1 (DCU)   Optimization1

E-1 (DCU) not   Operated2

E-2 (DCU) not   Operated3

1.

E-1 (DCU) UA,104 kcal/hour/oC

2.075

0

4.15

2.

LCGO flow through   E-2 (DCU), m3/hour

81.05

81.05

0

3.

E-2 (DCU) bypass   flow, m3/hour

0

0

81.05

4.

V-1 (DHDT) inlet temperature, oC

87.37

151.98

92.8

5.

P-1 (DHDT) discharge   temperature, oC

88.84

153.77

94.3

6.

P-1 (DHDT) fluid   vapor fraction

0

0

0

7.

P-1 (DHDT) fluid   vapor pressure at PT, kg/cm2a

0.2

1.4

0.25

8.

P-1 (DHDT) fluid   specific gravity at PT

0.7692

0.7222

0.7653

9.

P-1 (DHDT) fluid   viscosity at PT, cP

0.7539

0.3844

0.7062

10.

H-1 (DHDT) combined   inlet temperature, oC

288.39

293.96

288.82

11.

H-1 (DHDT) combined   outlet temperature, oC

295

295

295

12.

H-1 (DHDT) duty,106   kcal/hour

0.4918

0.1336

0.4647

Note :

1 = Software simulation for alternative 1 (1 unit of E-1 (DCU) is not operated).

2 = Software simulation for alternative 2 (2 units of E-1 (DCU) are not operated).

3 = Software simulation for alternative 3 (E-2 (DCU) is not operated or bypass).

Based on software simulation as it is shown in above table, it is concluded that only 2 out of 3 improvement studies are technically feasible, alternative 1 (1 unit of E-1 (DCU) is not operated) and alternative 3 (E-2 (DCU) is bypass).  Alternative 2 is technically not feasible because P-1 (DHDT) discharge temperature is 151.98 oC (which is higher than V-1 (DHDT) mechanical design temperature: 120 oC) and P-1 (DHDT) fluid vapor pressure at PT is 1.4 kg/cm2A (which is higher than P-1 (DHDT) fluid vapor pressure at PT: < 1 kg/cm2A).

5.3. Economical Study

5.3.1. Alternative 1: Economizing on Fuel Consumption of Fired Heater/Furnace of Distillate Hydro Treating Unit (DHDT) by Stopping 1 Unit out of 2 Units of Air Cooler E-1 (DCU)

Basis: 1 hour

Table III.

Economical Study of Economizing on Fuel Consumption of Fired Heater/Furnace of DHDT by Stopping 1 Unit out of 2 Units of Air Cooler E-1 (DCU) – Alternative 1

No.

Parameter

Value

1.

Power   needed for 1 unit E-1 (DCU), HP

17.4

2.

Power   needed for 1 unit E-1 (DCU), kwh

12.98

3.

Electricity   price, US$/kwh

0.12

Economizing on   Electricity for Stopping E-1 (DCU), US$/h

1.56

4.

H-1   (DHDT) Load Reduction, 106 kcal/h

0.1712

5.

Economizing   on Fuel Consumption of H-1 (DHDT), TSRF/h1)

0.0175

6.

Economizing   on Fuel Consumption of H-1 (DHDT), BSRF/h2)

0.1143

7.

Fuel   Oil Price, US$/BSRF

20.96

Economizing on Fuel   Consumption of H-1 (DHDT), US$/h

2.4

9.

H-1   (DHDT) Atomizing Steam Consumption, kg/kg of Fuel Oil

0.3

10.

Specific   Gravity of Fuel Oil

0.899

11.

LHV   of Fuel Oil, kcal/kg3)

10049.6

12.

Economizing   on Fuel Consumption of H-1 (DHDT), kg/j 4)

17.07

13.

Economizing   on Atomizing Steam Consumption of H-1 (DHDT), kg

5.121

14.

Steam   Price, US$/Ton

11.44

Economizing on   Atomizing Steam Consumption of H-1 (DHDT), US$/h

0.06

Total Economizing, US$/h

4.02

Total   Economizing,  US$/Year

35215

Note: 1) TSRF = (H-1 (DHDT) Load Reduction)/9 800 000

2) BSRF = TSRF x 6.531

3) Fuel Oil LHV = (11088 – 2100 x ρ152 + 757 x ρ15) x (1 – water content – ash

content – sulphur content) + (2450 x sulphur content)

4) Economizing on Fuel Oil = TSRF x 9800 x 1000 / Fuel Oil LHV

5.3.2. Alternative 3: Economizing on Fuel Consumption of Fired Heater/Furnace of Distillate Hydro Treating Unit (DHDT) by Operating All 2 Units of Air Cooler E-1 (DCU), but without Operating (Bypassing) Heat Exchanger E-2 (DCU)

Basis: 1 hour

Table IV.

Economical Study of Economizing on Fuel Consumption of Fired Heater/Furnace of DHDT by Operating All 2 Units of Air Cooler E-1 (DCU), but without Operating (Bypassing) Heat Exchanger E-2 (DCU) – Alternative 3

No.

Parameter

Value

1.

Economizing on E-2   (DCU) Sea Water Cooler Consumption, m3/h

66.45

2.

Sea Water Price, US$/m3

0.021

Economizing on E-2 (DCU) Sea Water Cooler   Consumption, US$/h

1.4

3.

H-1 (DHDT) Load   Reduction, 106 kcal/h

0.1983

4.

Economizing on Fuel   Consumption of H-1 (DHDT), TSRF/h1)

0.0202

5.

Economizing on Fuel   Consumption of H-1 (DHDT), BSRF/h2)

0.1319

6.

Fuel Oil Price, US$/BSRF

20.96

Economizing on Fuel   Consumption of H-1 (DHDT), US$/h

2.8

7.

H-1 (DHDT)   Atomizing Steam Consumption, kg/kg of Fuel Oil

0.3

8.

Specific   Gravity of Fuel Oil

0.899

9.

LHV of Fuel Oil,   kcal/kg3)

10049.6

10.

Economizing on Fuel   Consumption of H-1 (DHDT), kg/j 4)

19.7

11.

Economizing on   Atomizing Steam Consumption of H-1 (DHDT), kg

5.91

12.

Steam   Price, US$/Ton

11.44

Economizing on Atomizing Steam Consumption   of H-1 (DHDT), US$/h

0.07

Total Economizing, US$/h

4.27

Total   Economizing,  US$/Year

37405

Note: 1) TSRF = (H-1 (DHDT) Load Reduction)/9 800 000

2) BSRF = TSRF x 6.531

3) Fuel Oil LHV = (11088 – 2100 x ρ152 + 757 x ρ15) x (1 – water content – ash

content – sulphur content) + (2450 x sulphur content)

4) Economizing on Fuel Oil = TSRF x 9800 x 1000 / Fuel Oil LHV

6.    Conclusion

Technically, only 2 alternatives out of 3 possible improvement alternatives are feasible to be implemented, Economizing on Fuel Consumption of Fired Heater/Furnace of DHDT by Stopping 1 Unit out of 2 Units of Air Cooler E-1 (DCU) – Alternative 1 and Economizing on Fuel Consumption of Fired Heater/Furnace of DHDT by Operating All 2 Units of Air Cooler E-1 (DCU), but without Operating (Bypassing) Heat Exchanger E-2 (DCU) – Alternative 3.  Alternative 2 – Economizing on Fuel Consumption of Fired Heater/Furnace of DHDT by Stopping All 2 Units of Air Cooler E-1 (DCU) is technically not feasible, because inlet temperature of V-1 (DHDT) = 151.98 oC (compared to mechanical design temperature of V-1 (DHDT) = 120 oC) and vapor pressure of P-1 (DHDT) fluid at PT = 1.4 kg/cm2A (compared to design vapor pressure of P-1 (DHDT) fluid at PT < 1 kg/cm2A).

Based on economical study, alternative 3 gives more potential benefit compared to alternative 1.  Therefore, Process Engineer recommends implementing alternative 3 for economizing on fuel consumption of fired heater of DHDT.

Nevertheless, it must be noted that during DHDT shutdown and LCGO product is routed to LCGO storage tank, E-2 (DHDT) MUST NOT be bypassed and operation scheme must be back to original scheme, E-1 (DHDT) and E-2 (DHDT) are operated to get LCGO product temperature less than 55 oC (LCGO storage tank maximum temperature).  Therefore, Process Engineer recommends revising Standard Operating Procedure to adopt this scenario.