Gr Report of Training-libre

REPORT

ON SUMMER VOCATIONAL TRAINING

INDIAN OIL CORPORATION LIMITED GUJARAT REFINERY

PERIOD OF TRAINING (23rd JUNE – 12th

JULY 2014)

Submitted By :

JADAV RAJU G. En Roll: 120283105016

B.E (Chemical Engineering)

L.D.COLLEGE OF ENGINEERING

AHMEDABAD- 380 015

PREFACE

Though it has been said that best friend a man can ever get is a book but we at this juncture realize that only books cannot give all the information a person seeks. When any student is unable to understand a particular topic, he is advised to imagine the whole matter and then try to understand it. Normally, this method succeeds. But in engineering stream considering the study of wide range of process and equipments involved in it, it is hard to understand the unit operations and processes just through books or even with imagination .Unless one happens to see the process, equipments, he is like a soldier who knows to fire the gun but is yet to face a war. Industrial training is one of the most vital part of a syllabus of chemical engineering, which not only teaches one the industrial unit operations, equipments and other technical aspects, but also teaches discipline, interaction with various people irrespective of their posts, the importance of teamwork, etc. This report contains a brief introduction to GUJRAT REFINERY and knowledge gathered about various units in refinery during the training.

ACKNOWLEDGEMENT

I would like to express my gratitude to all those who gave me the possibility to complete this training. I want to thank the department of training and management of Gujarat refinery for giving me permission to commence this training. I have furthermore to thank the officers of production who giving me such knowledge of about the plant and production process. It is really great opportunity for me by which I had learned here many more of refinery. I am deeply indebted to Gujarat Refinery who given such opportunity to students by which they complete their vocational training which is the parts of the course. Without any moral support and help I was not able to visit the plant and learn about the refinery. I would like to give my special thanks to the person who supported me through the training at the day of starting to the end of the training. Our special thanks to Mr. A.C.SHEKHAR Chief Manager (MS, T&D) Mr. C.K.SINHA PNM (North Block-DCU, VGO-HDT) Mr. N. VENKATESH DMPN (DCU) Mr. S.K.SIGH PNE (GRE) Mr. M.KARANKUMAR PNE(GRE)

Topic:

Overall View of Gujarat Refinery with Particular Sequence to MS and Quality Up gradation.

CONTENTS

Sr. No

TOPIC PAGE NO.

1 INTRODUCTION TO IOCL 1 2 GUJARAT REFINERY 2 3 UNITS AT GUJARAT REFINERY 5 4 NORTH BLOCK GUJARAT REFINARY 6 DELAYED COKER UNIT (DCU) 6 5 GUJARAT REFINERY EXPANSION (GRE) 13 CRUDE DISTILLATION UNIT (CDU) 13 VACUUM DISTILLATION UNIT (VDU) 20 6 LEARNING 23 7 BIBLIOGRAPHY 24

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1)

INTRODUCTION

INDIAN OIL CORPORATION LTD. (IOCL)

Indian Oil, the largest commercial enterprise of India (by sales turnover), is India’s sole representative in Fortune's Prestigious listing of the world's 500 largest corporations, ranked 88 for the year 2013. It is also the 17th largest petroleum company in the world. Indian Oil has a sales turnover of Rs. 4,73,210 crore and profits of Rs. 7,019 crore. Indian Oil has been adjudged second in petroleum trading among the 15 national oil companies in the Asia-Pacific region. As the premier National Oil Company, Indian Oil’s endeavor is to serve the national economy and the people of India and fulfill its vision of becoming “ An Integrated, Diversified And Transnational Energy

Major.” Beginning in 1959 as Indian Oil Company Ltd, Indian Oil Corporation Ltd. was formed in 1964 with the merger of Indian Refineries Ltd. (Est. 1958).As India's flagship national oil company, Indian Oil accounts for 56% petroleum products market share,42% national refining capacity and 67% downstream pipeline throughput capacity. IOCL touches every Indian’s heart by keeping the vital oil supply line operating relentlessly in every nook and corner of India.

It has the backing of over 33% of the country’s refining capacity as on 1St

April 2002 and 6523 km of crude/product pipelines across the length and breadth of the country.

IOCL’s vast distribution network of over 20000 sales points ensures that essential petroleum products reach the customer “at the right place and at the right Time.” Indian Oil controls 10 of India's 18 refineries - at Digboi, Guwahati, Barauni, Koyali, Haldia, Mathura,Panipat, Chennai, Narimanam and Bongaigaon

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2) GUJARAT REFINERY

The Gujarat Refinery is an oil refinery located at Koyali (Near Vadodara) in Gujarat, Western India.

It is the Second largest refinery owned by Indian Oil Corporation after Panipat Refinery. The refinery is currently under projected expansion to 18 MMTPA

History

Following the conclusion of the Indo-Soviet Treaty of Friendship and Cooperation in February 1961, a site for the establishment of a 2 million metric ton per annum (MMTPA) oil refinery was selected on 17 April 1961.[2] Soviet and Indian engineers signed a contract in October 1961 for the preparation of the project. Prime Minister Jawaharlal Nehru laid the foundation stone of the refinery on 10 May 1963.

The refinery was commissioned with Soviet assistance at a cost of Rs.26 crores began production in October 1965. The first crude distillation unit with a capacity of 1 MMTPA was commissioned for trial production on 11 October 1965 and achieved its rated capacity on 6 December 1965. Throughput reached 20% beyond its designed capacity in January 1966. President Sarvepalli Radhakrishnan dedicated the refinery to the nation with the commissioning of second crude distillation unit and catalytic reforming unit on 18 October 1966.

The third 1 MMTPA distillation unit was commissioned in September 1967 to process Ankleshwar and North Gujarat crudes. In December 1968, Udex plant was commissioned for production of benzene and toluene using feedstock from CRU. By 1974-75 with in-house modifications, the capacity of the refinery increased by 40% to a level of 4.2 MMTPA.

To process imported crude the refinery was expanded during 1978-79 by adding another 3 MMTPA crude distillation unit along with downstream processing units including vacuum distillation, visbreaker and bitumen blowing units. By 1980-81 this unit started processing Bombay High crude in addition to imported

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crudes. It was the first time that Indian engineers independently handled a project of that scale.

To recover products from the residue, secondary processing facilities consisting of fluidized catalytic cracking unit of 1 MMTPA capacity along with a feed preparation unit of 1 MMTPA capacities, were commissioned in December 1982.

The refinery set up pilot distillation facilities for the production of n-Heptane and light aluminum rolling oils. To enable absorption of increased indigenous crudes the refinery's capacity was further increased to 9.5 MMTPA.

In 1993-1994, Gujarat commissioned the country's first hydrocracker unit of 1.2 MMTPA for conversion of heavier ends of crude oil to high value superior products. India's first diesel hydridesulfurisation unit to reduce sulfur content in diesel was commissioned in June 1999. An methyl tertiary butyl ether unit was commissioned in September 1999 to eliminate lead from motor fuels. The facility conceptualised and commissioned South Asia's largest centralised effluent treatment plant by dismantling the four old ETP's[expand acronym] in June 1999.

By September 1999 with the commissioning of an atmospheric distillation unit, Gujarat Refinery further augmented its capacity to 13.7 MMTPA making it the largest public sector undertaking refinery of the country.

A project for production of linear alkyl benzene from kerosene streams was implemented in August 2004. It is the largest grassroots single train Kerosene-to-LAB unit in the world, with an installed capacity of 1.2 MMTPA. To meet future fuel quality requirements, MS[expand acronym] quality improvement facilities were commissioned in 2006. The Residue Upgaration Project undertaken by the Gujarat Refinery was completed by 2011 which increased the high sulfur processing capacity of Gujarat refinery, improved the distillate yield as well produce BS III & IV quality of MS and HSD.

The Residue upgradation project came in two parts namely, the south block which consisted of HGU-III, SRU-III, DHDT and ISOM units and the north block consisted of VGO-HDT and DCU units. To support the new units a new Co-Generation Plant (CGP) and Heat Recovery Steam Generation (HRSG) were also commissioned

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PROCESSING CRUDE: Gujarat Refinery is designed to processes indigenous as well as imported crude oil. On an average itprocesses approximately three lakh eight thousand metric tonnes crude per day. Out of the crude slot itreceives, refinery processes around 45% imported crude Gujarat refinery•s manufacturing and storage facilities consist of 26 major process units, 28 product lines and crude storage tanks with capacity ranging from 300 to 65,000 KLs. South Gujarat Crude: 2.3MMTPA; supply from ONGC South Gujarat pipeline. North Gujarat: 3.5MMTPA; supply from ONGC North Gujarat pipeline.Imported low / high Sulphur crude & Bombay high: 6.2 MMTPA Supply from Salaya - Viramgam -Koyali pipeline. SALIENT FEATURE OF REFINERY:

First Riser Cracker FCCU in the country. First Hydro cracker in the country. First Diesel Hydro De-sulphurisation Unit. First Spent Caustic Treatment Plant in refineries. First Automated Rail Loading Gantry. First LPG Mounded Bullets in Indian Refineries. Operates Southeast Asia’s biggest Centralized Effluent Treatment

Plant (CETP) Process Control: Using the latest electronic technology to monitor and control the plants, engineers run the process units around the clock, 7 days a week. From control rooms located in each operations area, technical personnel use a computer-driven process control system with console screens that display color interactive graphics of the plants and real-time (current) data on the status .

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3) UNITS AT GUJARAT REFINERY

GR1

Atmospheric Distillation Units, AU1 & AU2 4.2 MMTPA

AU5 3.0 MMTPA

Catalytic Reforming Unit, CRU 0.33 MMTPA

GR2

AU3 2.7 MMTPA

UDEX 0.166 MMTPA

FGH(Food Grade Hexane) 0.03 MMTPA

MTBE 47 MMTPA

BUTENE-1 2 MMTPA

GRE

CDU(Crude Distillation Unit) 3.8 MMTPA

VDU(Vacuum Distillation Unit) 1.2 MMTPA

BBU(Bitumin Blowing Unit) 0.5 MMTPA

VBU(Visbreaker Unit) 1.6 MMTPA

GRSPF

FPU (feed preparation unit) 2.0 MMTPA

FCC(fluid catalytic cracking) 1.5 MMTPA

Ghc

Hg (hydrogen generation unit) 38000 MMTPY

Hcu (hydro cracking unit) 1.2 MMTPA

Hydrogen-2 10000

Dhds (Diesel Hydro De-Sulfurization Unit 1.4 MMTPY

Sru (sulphur recovery unit) 88 MMTPD

POWER GENERATION AND EFFULENT TREATMENT

Cgp (cogeneration plant) 30*3 mw

Tps (thermal power station) 12*2+12.5 mw

Cetp (central effulent treatment plant) 1500 m3/h

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4) NORTH BLOCK GUJARAT REFINERY

DCU (Delayed Coker Unit) VGO-HDT (Vacuum Gas Oil Hydrotrater)

•

Delayed Coker Unit

WHAT IS DELAYED COKING? Delayed coking is a thermal cracking process used in petroleum refineries to upgrade and convert petroleum residuum (bottoms from atmospheric and vacuum distillation of crude oil) into liquid and gas product streams leaving behind a solid concentrated carbon material, petroleum coke. A fired heater with horizontal tubes is used in the process to reach thermal cracking temperatures of 485 to 505oC (905 to 941oF). With short residence time in the furnace tubes, coking of the feed material is thereby “delayed” until it reaches large coking drums downstream of the heater. Three physical structures of petroleum coke: shot, sponge, or needle coke can be produced by delayed coking. These physical structures and chemical properties of the petroleum coke determine the end use of the material which can be burned as fuel, calcined for use in the aluminum, chemical, or steel industries, or gasified to produce steam, electricity, or gas feedstocks for the petrochemicals industry. Vacuum Reduced Crude Processing Options or End Uses

• Delayed Coking

• Visbreaking - Primary function is to reduce viscosity of the oil with some production of heavy gas oil.

• Resid FCC - Residuum Fluid Catalytic Cracking, metals deactivate catalyst, must use passivating chemicals to reduce unwanted reactions

• Resid Hydrocracking - Feed is contacted with a catalyst and hydrogen at high temperature and pressure to remove sulfur,

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nitrogen, and some aromatic compounds with some conversion to lighter liquid products.

• ROSE - Residual Oil Supercritical Extraction for production of metal free gas oil, asphaltenes and resins

• Propane Deasphalting / Bright Stock - Solvent extraction of heavy lubrication oils

• Road Asphalt

• Roofing Asphalt - May require air blowing to increase hardness • Fuel Oil - Burner and slow RPM marine diesel • MODERN DELAYED COKING PROCESS: The delayed coker is the only main process in a modern petroleum refinery that is a batch continuous process. The flow through the tube furnace is continuous. The feed stream is switched between two drums. One drum is on-line filling with coke while the other drum is being steam-stripped, cooled, decoked, pressure checked, and warmed up. The overhead vapors from the coke drums flow to a fractionator, usually called a combination tower. This fractionator tower has a reservoir in the bottom where the fresh feed is combined with condensed product vapors (recycle) to make up the feed to the coker heater.

• Delayed Coking Drum Cycle: Since the feed stream is regularly switched between drums, a cycle of events will occur on a regular interval depending on the delayed coking unit feed rate, drum size, and throughput capacity. Most typical delayed cokers currently run drum cycle times of about 16 hours with one drum filling on-line while its counterpart is off-line for stripping, cooling, and decoking. Drum cycle event approximate time requirements for such a cycle are shown below in Table 1. Shortening the cycle time is one method of increasing throughput on delayed coking units. One refinery regularly runs 12 hour drum cycles and has attempted 10 and 11 hour cycles, but cycles this short are extremely difficult due to minimum time requirements for each of the steps of the drum cycle. Some of the more important drum cycle steps are described in detail in the following sections.

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Table :Typical Short Cycle Coking Operations

Drum Cycle Hours Steam to Fractionator 0.5 Steam to Blow Down 0.5

Depressure, Water Quench and Fill 4.5 Drain 2.0 Unhead Top and Bottom 0.5 Cutting Coke 3.0 Rehead / Steam Test / Purge 1.0 Drum Warm-Up (Vapor Heat) 4.0

----------------------------------------------------------------- Total Time 16.0

s

• Drum Warm-Up (Vapor Heat): To prepare the cold empty coke drum to be put back on-line to receive the hot feed, hot vapors from the on-line drum are circulated into the cold empty drum. The hot 415°C (780°F) vapors condense in the cold drum, heating the drum to a target temperature of around 340°C (650°F). While the drum is heating, the condensed vapors are continuously drained out of the drum.

• On-line Filling: After the cold drum has been vapor heated for a few hours, hot oil from the tube furnace at about 485°C (905°F) is switched into the drum. Most of the hot vapors condense on the colder walls of the drum, and a large amount of liquid runs down the sides of the drum into a boiling turbulent pool at the bottom of the drum. The drum walls are heated up by the condensing vapors, so less and less vapors are condensing and the liquid at the bottom of the drum starts to heat up to coking temperatures. A main channel is formed similar to the trunk of a tree. As time goes on the liquid pool above the coke decreases with the vapors going to the fractionator, the vapor line is vented to blowdown system. Steam is increased for a short time or in some cases water is immediately introduced at the bottom of the drum which instantly flashes to steam.

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The steam is backed out and the flow of cooling water is gradually increased. The top vapor temperature in the drum may increase slightly at first before cooling due to the increased flow of steam up through the coker.

• Water Cooling / “Drum Bulging.”: The rate of cooling water injection is critical. Increasing the flow of water too rapidly can “case harden” the main channels up through the coker without cooling all of the coke radially across the coke bed. The coke has low porosity (the porosity comes from the thermal cracking) which then allows the water to flow away from the main channels in the coke drum. Porosity of delayed coke has been measured experimentally in the past by measuring water flow through cores about the size of hockey pucks cut from large chunks of needle coke from different areas of a commercial coke drum. Most of the coke cores were found to have no porosity except the coke right at the wall which had some porosity . This explains problems that have been found to occur with drums bulging during cool down. If the rate of water is too high, the high pressure causes the water to flow up the outside of the coke bed cooling the wall of the coke drum. Coke has a higher coefficient of thermal expansion than does steel (154 for coke versus 120 for steel, cm/cm/°C x 10-7). This was measured in the transverse direction from a chunk of needle coke. The coefficient of thermal expansion for raw sponge coke is probably even greater than that of the needle coke tested. Schematic flow diagram and description The flow diagram and description in this section are based on a delayed coking unit with a single pair of coke drums and one feedstock furnace. However, as mentioned above, larger units may have as many as 4 pairs of drums (8 drums in total) as well as a furnace for each pair of coke drums. Residual oil from the vacuum distillation unit (sometimes including high-boiling oils from other sources within the refinery) is pumped into the bottom of the distillation column called the main fractionator. From there it is pumped, along with some injected steam, into the fuel-fired furnace and heated to its thermal cracking temperature of about 480 °C. Thermal cracking begins in the pipe between the furnace and the coke

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drum effluent is vapor except for any liquid or solids entrainment, and is directed to main fractionator where it is separated into the desired boiling point fractions.

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drums, and finishes in the coke drum that is on-stream. The injected steam helps to minimize the deposition of coke within the furnace tubes. Pumping the incoming residual oil into the bottom of the main fractionator, rather than directly into the furnace, preheats the residual oil by having it contact the hot vapors in the bottom of the fractionator. At the same time, some of the hot vapors condense into a high-boiling liquid which recycles back into the furnace along with the hot residual oil. As cracking takes place in the drum, gas oil and lighter components are generated in vapor phase and separate from the liquid and solids. The The solid coke is deposited and remains in the coke drum in a porous structure that allows flow through the pores. Depending upon the overall coke drum cycle being used, a coke drum may fill in 16 to 24 hours. After the drum is full of the solidified coke, the hot mixture from the furnace is switched to the second drum. While the second drum is filling, the full drum is steamed out to reduce the hydrocarbon content of the petroleum coke, and then quenched with water to cool it. The top and bottom heads of the full coke drum are removed, and the solid petroleum coke is then cut from the coke drum with a high pressure water nozzle, where it falls into a pit, pad, or sluiceway for reclamation to storage.

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Uses Of Petroleum Coke: The product coke from a delayed coker has many commercial uses and applications. The largest use is as a fuel. The uses for green coke are: As fuel for space heaters, large industrial steam generators, fluidized

bed combustions, Integrated Gasification Combined Cycle (IGCC) units and cement kilns

In silicon carbide foundries For producing blast furnace coke The uses for calcined coke are: As anodes in the production of aluminum In the production of titanium dioxide As a carbon raiser in cast iron and steel making Producing graphite electrodes and other graphite products such as

graphite brushes used in electrical equipment In carbon structural materials

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5) GRE (GUJARAT REFINERY EXPANSION) UNITS:

CDU (Crude Distillation Unit) VDU (Vacuum Distillation Unit) BBU (Bitumen Blowing Unit) VBU (Visbreaker Unit)

Crude Distillation Unit(CDU): AU-4

The crude oil distillation unit

The crude oil distillation unit (CDU) is the first processing unit in virtually all petroleum refineries. The CDU distills the incoming crude oil into various fractions of different boiling ranges, each of which are then processed further in the other refinery processing units. The CDU is often referred to as the atmospheric distillation unit because it operates at slightly above atmospheric pressure. Below is a schematic flow diagram of a typical crude oil distillation unit. The incoming crude oil is preheated by exchanging heat with some of the hot, distilled fractions and other streams. It is then desalted to remove inorganic salts (primarily sodium chloride). Following the desalter, the crude oil is further heated by exchanging heat with some of the hot, distilled fractions and other streams. It is then heated in a fuel-fired furnace (fired heater) to a temperature of about 398 °C and routed into the bottom of the distillation unit. The cooling and condensing of the distillation tower overhead is provided partially by exchanging heat with the incoming crude oil and partially by either an air-cooled or water-cooled condenser. Additional heat is removed from the distillation column by a pump around system as shown in the diagram below. As shown in the flow diagram, the overhead distillate fraction from the distillation column is naphtha. The fractions removed from the side of

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the distillation column at various points between the column top and bottom are called sidecuts. Each of the side cuts (i.e., the kerosene, light gas oil and heavy gas oil) is cooled by exchanging heat with the incoming crude oil. All of the fractions (i.e., the overhead naphtha, the side cuts and the bottom residue) are sent to intermediate storage tanks before being processed further. Overview of Crude Units Crude units are the first units that process petroleum in any refinery. There objective is to separate the mixture into several fractions like naphtha, kerosene, diesel and gas oil. A schematic diagram of an atmospheric crude fractionation unit is shown in Figure 1-1.

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Crude oil contains salts which can be harmful to downstream equipment and must be removed. To remove the salts, water is mixed with the crude oil and typically heated to temperatures between about 215 oF to about 280 oF and allowed to separate in the desalter. The desalted crude enters another heat exchanger network. Both heat exchanger networks make use of the vapors of the main column condenser, the pump-around circuit streams (PA1, PA2 and PA3), and the products that need to be cooled. Then, the preheated crude enters the furnace, where it is heated to about 340-372 oC (644-700 oF). The partially vaporized crude is fed into the feed region (called flash zone) of the atmospheric column, where the vapor and liquid separate. The vapor includes all the components that comprise the products, while the liquid is the residue with a small amount of components in the range of gas oil. These components are removed from the residue by steam stripping at the bottom of the column. Products are withdrawn from the side of the column and side strippers are used to help controlling the composition of light components. In addition, to more effectively remove heat, liquid is extracted at various points of the column and cooled down to be reinjected at a different position on the column. Cooling water and sometimes air

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coolers are used in the heat exchangers PA1, PA2 and PA3, but it is always more advantageous to have these streams release their heat to the raw crude oil in the heat exchanger networks (HEN), usually called pre-heatingtrains. Several different designs and configurations for the heat exchanger network in the conventional crude oil distillation unit are possible. Figure 1-2 shows one particular instance of a preheating train, not necessarily the best or most recommended one (efficient ones are discussed later). In addition, in some oil distillation units, gas oil is not produced and instead becomes part of the residue. Such units contain one less sidestripper and one less pump-around than those shown in Figure 1-1 and Figure 1-2. Further, in units in which gas oil is not produced, the diesel may be further separated into heavy and light diesel.

The topped crude leaving the atmospheric tower still contains significant amount of valuable oils. These oils cannot be distillated at atmospheric pressure because the temperature required would be so high that severe thermal cracking takes place. Figure 1-3 depicts such a unit.

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Note first that this unit does not have a condenser and does not feature side strippers either, simply because products do not have specifications on their light end. However, side strippers can be used in specific cases, such as lube base oil production. Figure 1-3 shows that light vacuum gas oil (LVGO) and heavy vacuum gas oil (HVGO),are produced. Sometimes, depending on its properties, LVGO is blended with other products like atmospheric diesel. Both are typically used as feed to fluid catalytic cracking units. The vacuum distillation consists of the vacuum furnace, vacuum tower and the vacuum producing system. The topped crude is heated up in the vacuum furnace to about 400 °C. The temperature is controlled to be just below the temperature of thermal decomposition. Although a single cut of vacuum gas oil (VGO) is allowed in some cases, drawing LVGO and HVGO separately is more beneficial from the point of view of energy savings, because the resultant HVGO draw temperature is 90-120 °C higher than the corresponding draw temperature of a single VGO cut. Lighter components are removed from the residue by steam stripping. In addition coke formation is reduced by circulating partially cooled bottoms to quench the liquid to a lower temperature. Because the heavy crude fraction contains metal complexes (asphaltenes and porphyrines), which are catalyst poisons for downstream processes, sometimes a

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recirculation of “wash oil” in the bottom part (not shown in the figure) is included to prevent these compounds to reach the HVGO. In the preheating train, the crude is under pressure to suppress vaporization. In the case of a light crude, the pressure required to suppress vaporization is too high. The solution is to separate some light components before heating the crude further in the preheat train (Figure 1-4 ). The light components separated in the pre-flash drum are sent to the column directly. In the pre-fractionation design (Figure 1-5), the light components are separated in a pre-fractionation column. Thus, in the pre-flash design, components in the range of naphtha are condensed in the condenser of the atmospheric tower, while in the prefractionation design, these components are split into two fractions: light naphtha condensed in the condenser of the pre-fractionation condenser and heavy naphtha condensed in the condenser of the atmospheric tower.

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The pre-fractionation design, however, is considered to be similar to the pre-flash design when energy consumption is considered (Bagajewicz and Ji, 2002). Because the condensation heat for naphtha (or light naphtha plus heavy naphtha) is constant, the only difference is that the pre-fractionation design provides this heat in two condensers with different temperatures. When there is significant heat surplus in the temperature range of the condensers (intermediate and light crudes), the difference does not affect energy consumption.

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Vacuum Distillation Unit (VDU): Vacuum distillation is a method of distillation whereby the pressure above the liquid mixture to be distilled is reduced to less than its vapor pressure (usually less than atmospheric pressure) causing evaporation of the most volatile liquid(s) (those with the lowest boiling points). This distillation method works on the principle that boiling occurs when the vapor pressure of a liquid exceeds the ambient pressure. Vacuum distillation is used with or without heating the mixture The Vacuum Distillation Unit (VDU) was designedto process8,00,000 TPA of RCO (370°C + 50:50 North Rumaila & Arab Light).After low cost 1999 revamp VDU can process 1.2 MMTPA of RCO, Heavy Diesel astop product isused as HSD, LVGO+HVGO used as VGO for FCCU feedstock. Presentlythere is a provision for withdrawal of three side cuts. The Vacuum Distillation Unit (VDU) was originallydesigned to process Reduced Crude Oil (RCO) obtained ex CDU(Crude Distillation Unit) while processing imported crude (50: 50mixture of North Rumaila and Light Arabian Crude Oils). However, RCOobtained from various imported crudes and indigenous crudes (BombayHigh, North Gujarat, and South Gujarat Mix.) has been processedsuccessfully.

FEED:

By distilling the RCO under vacuum in a singlestage column, it produces Light vacuum Gas Oil (LVG0), HeavyVacuum Gas Oil (HVGO) and Vacuum Residuum (VR). Slop cut(distillate between HVGO and VR) production facility has been providedsince 1988.LVGO - used as blending component for LDO or HSD or as feedcomponent for FCCUalong withHVGO.HVGO - used as a feed componentfor FCCU.VACUUM RESIDUUM (VR) - (Imported) is used as feed forBitumen Unit.Excess VR and HVG Oil can be used as feed components to theVisbreaker Unit. Surplus BH VR (while processing Bombay High RCO inVDU) is used as blending component for LSHS.

PRODUCTS:

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PROCESS FLOW DIAGRAM:

PROCESS FLOW DISCRIPTION:

Reduced crude oil, RCO is received in feed surge drum from storagetanks. Hot RCO can be received from CDU. RCO is pumped bycharge pumps to a series of preheat exchangers and then tofurnace from where feed goes to column. At the end of preheating bypreheat exchanger train feed gets heated up to 305°C in case of hotfeed and up to292°C in case of coldfeed.Preheated RCO is split into two passes and introduced to VacuumHeater/Furnace under pass flow control for each

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pass. MP steam isinjected in each pass to encourage vaporization of feed in the coils.Coil outlet temperature of 395 -398°C is maintained. The partiallyvaporized RCO is introduced in flash zone of column. LPsteam superheated up to 350°C in the heater is used as stripping steam in the stripping section of the vacuum column. Vaporized RCOalong with steam rises through the vacuum column and is fractionatedinto two side withdrawals.VR along with quench stream is withdrawn from the column bottomby pumps. After preheating feed, a quench stream is routed back to the column tomaintain bottom temperature of 355°C to avoid coking in the columnboot. Further VR goes to LP steam generator and gets cooled up to150 0 C. VR routing is as follows: (1) Hot VR to BBU, (2) Hot VR to VBU,(3) Hot VR to VR burning facility, (4) Hot VR to IFO drum, (5) Direct VRinjection in BBU after cooling, & (6) After cooling in tempered watercooler VR is routed to storage at 150°C. The desired vacuum is created in the vacuum column by the vacuum system consisting of multistage ejectors, precondenser, intermediate condenser, after condenser and hot well. The hot well islocated at grade level and correspondingly ejectors are elevated toprovide barometric legs. Small amount of oil carried over withsteam from the column is removed from the seal pot by pump and isrouted to slop or to HSD. Sour water from the seal pot is pumped outby pumps to sour water system.

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6)

LEARNING:

I have gained knowledge by this training in various aspects as an engineer, as I had firsthand experience in Indian oil corporation limited. Training here, enhanced my cognition, as the employee has explained, with commitment, all the doubts and question that arise in my mind. This chance thrown at me, was a boon as I had only seen that real about all the equipment seen in the industry, which now , I am able to distinguish well enough. This was not possible with books knowledge. I heartily thanks all employees of IOCL to have help me all throughout my training.

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7)

BIBLIOGRAPHY:

1. IOCL MANUALS 2. www.petroleumrefining.com, Petroleum Refining Engineering

Website. 3. Unit Operations of Chemical Engineering by Dennis C. Prieve,

Pittsburg. 4. www.engineeringtoolbox.com, Chemical Engineering Website 5. Petroleum Refining by James H. Gary, Colorado