AREPORT ON WINTER TRAINING

INOIL AND NATURAL GAS CORPORATION LIMITED

HAZIRA, SURAT

Training Period: 7th DEC 2015 - 6th JAN 2016

SUBMITTED BY

DEEP PATEL

B. Tech 3rd YEARMECHANICAL ENGINEERING DEPARTMENT

S. V. NATIONAL INSTITUTE OF TECHNOLOGY , SURAT

PREFACE

Industrial Training refers to work experience that is relevant to professional developments an essential component in the development of the practical and professional skill required of manger and an aid to prospective employment. The summer training is an ideal opportunity for the student to have a firsthand experience with the different function of the industry/corporate sector. It is famous saying that the “person who has read 1000’s of pages is not worth than the person who has travelled for 100’s of meters”.

Teaching gives the knowledge of theoretical aspects of management but implementation of theory gives practical knowledge of management field. The aim of this training is to introduce the fundamentals and the basic principles of financial management and business accounting in real life day to day application of business transition. Practical Knowledge of theory is of grater important for a finance student. This project report is an outline of what we have learnt during our training period at Oil& Natural Gas Corporation Limited (ONGC), one of the prestigious public sector companies running with strategy values and time management. We are thankful to Oi l & Natura l Gas Corpora t ion Limi ted for g iv ing us such a va luable opportunity to work with them.

We are thankful to Oi l & Natura l Gas Corpora t ion Limi ted for g iv ing us such a va luable opportunity to work with them.

ACKNOWLEDGEMENT

It has been rightly said, “Whenever people are willing but unable to perform particular task, they need cooperation and guidance of experienced people which is quite imperative in achieving the desired goals.” We sincere acknowledgement to oil and natural gas corporation ltd. for giving us a valuable opportunity to work with them. This project report is dedicated to all the people, whom we met, took guidance, talked and gained knowledge from them.

We are indebted and whole -hear tedly thankful for the ass is tance received f rom various individuals in making this project a success. We have no words to express our gratitude towards those who were constant ly involved wi th us throughout our wonderful exper ience working with the project.

We are highly thankful and deeply indebted to MR. RADHAVINOD SIR AND MR. MUKUNDAN SIR Who incessantly guided us till last word of this project report and provided an estimable guidance. We are also thankful to MR. BHAUMIK SIR , MR. MUNDA SIR. They made numerous valuable suggestions and corrections, which greatly improved the quality of our work. In spite of being busy with their routing work  they spend qual i ty t ime wi th us and never hes i ta ted to coopera te and help us out wi th our  problems as and when required. The practical and the theoretical knowledge that we have gained from them will help us in enhancing our career and managing things in a better way.

ONGC AS PROCESSING INDUSTRY: Oil and Natural Gas Corporation is a public sector petroleum company involved in wide scale exploitation of oil as well as natural gas from the Indian mainland as well as from Arabian Sea and Indian Ocean .ONGC is one among the Indian Government’s Navrathna Companies which involves the most profit making nine public sector companies and hence is one of the most profit making companies in India.

Foundation:

In August 1956, the Oil and Natural Gas commission was formed. Raised from meredirectorate status to commission, it had enhanced powers. In 1959, these powers were further enhanced by converting the commission into a statutory body by an act of Indian Parliament Oil and Natural Gas Corporation Limited (ONGC) (incorporated on June 23, 1993) is an Indian Public Sector Petroleum Company. It is a fortune global 500 companies ranked 335th,and contributes 51% of India’s crude oil production and 67% of India’s natural gas production in India. It was

set up as a commission on August 14, 1956. Indian government holds 74.14 %

equity stake in this company .ONGC is one of Asia’s largest and most active companies involved in exploration and production of oil .It is involved in exploring for and exploiting hydrocarbons in 26 sedimentary basins of India. It produces 30% of India’s crude oil requirement. It owns and operates more than 11,000 kilometers of pipelines in India. In 2010, it was ranked 18th in the  Plants   Top 250 Global Energy Company Rankings and is ranked 413st in the 2012   Fortune Global 500   list. It is the largest company in terms of market cap in India.

ONGC Represents India’s Energy Security   ONGC has single-handedly scripted India’s hydrocarbon saga by:

Establishing 7.38 billion tons of In-place hydrocarbon reserves with more than 300discoveries of oil and gas; in fact, 6 out of the 7 producing basins have been discovered by ONGC: out of these In-place hydrocarbons in domestic acreages,

Ultimate Reserves are 2.60 Billion Metric tonns (BMT) of Oil Plus Oil Equivalent Gas (O+OEG).

Cumulatively produced 851 Million Metric Tonnes (MMT) of crude and 532 BillionCubic Meters (BCM) of Natural Gas, from 111 fields.

ONGC has bagged 121 of the 235 Blocks (more than 50%) awarded in the 8 rounds of bidding, under the New Exploration Licensing Policy (NELP) of the Indian Government.

ONGC’s wholly -owned subsidiary ONGC Videsh Ltd. (OVL) is the biggest Indian multinational, with 33 Oil & Gas projects (9 of them producing) in 15 countries, i.e. Vietnam, Sudan, South Sudan, Russia, Iraq, Iran, Myanmar, Libya, Cuba, Colombia ,Nigeria, Brazil, Syria, Venezuela and Kazakhstan.

ONGC as Processing Industry:

 Any process industry can be solely divided into 4 parts:1.Process plant2.Utilities3.Environmental system4.Safety system

1.Process Plant:This part consist the basic purpose of that process industry for which it has been established. ONGC Hazira plant basically produces LPG and other value added products and pumps the stabilized oil to different refineries. In sum to get this purpose there is overall two plant:

a)Co-generation Plantb)Oil and Gas process Plant Co-generation plant can be also sub divided into mainly 3 different process units:

Gas Turbine Boilers(heat recovery steam generation) Gas fired boilers

Oil and gas process plant can be sub divided into 6 different processing units:

Slug catcher unit Condensate fractionation unit Gas sweetening unit

Crude separation unit LPG recovery unit Ethane propane recovery unit

2.Utilities:

Utilities plays very important role in any process industry. They provide support to process plant for the smooth running and continuous production as in our case. The basic utilities which are very necessary in our case are:

Effluent treatment Instrument air  Air dryer Flare system Blow down system Soft water system Fuel gas Inert gas system

3.Environment System:This system monitors the effect of plant on environment by continuous monitoring inside and outside surrounding of plant and always tries to maintain a minimum national standard of different environmental parameters. If this minimum standard is not achieved by the plant then government has to shut that industry as per environmental law. It can be also categorized in two parts:

 A) Primary environmental system:

 It is directly related to the health precaution and keeps on check on severe affect on environment like the surrounding temperature, H2S gas concentration in the atmosphere, suspended particles and carbon concentration etc. as these changes affect the people and works health working or living in the surrounding of the planet. 

B) Secondary environmental system:This system is not related to health but works for the sake of environmentalprotection and welfare. Plantation, nitrogen’s oxide removal system comes under this system category.

4. Safety system:

This system maintains the safe working condition in this plant is very much prone to fire as the air in the surrounding contains lots of hydrocarbon and oil vapours. So any small spark can produce large scale destruction. This system consist of 

Firewater unit Gas detection unit Static charge removal unit

THE INDUSTRIAL PRIDE OF INDIA:

The ONGC Gas processing unit is located at Hazira on the suburbs of Sura t c i ty in Gujara t . HGPC plant was spec if ica l ly la id for process ing Natural gas, which is found at Bombay High. This plant comes under the Mumbai Region Business Centre (MRBC). Hazi ra Gas Process ing Complex was se t up in September 1985 to receive gas from Mumbai High initially and subsequently to process sour  Natural Gas from Basin and other offshore fields. Sour gas along with associate condensate is transported through two sub-sea pipelines: one 36” d iameter (231 kms) and the o ther 42” d iameter (244 kms) f rom bas in o f f s h o r e p r o c e s s p l a t f o r m t o H a z i r a p l a n t . F r o m h e r e t h e n a t u r a l g a s production is carried out which on earlier stage is supplied to GAIL and HBJ (Hazira Bijapur Jagdishpur) pipeline .W i t h t h e d i s c o v e r y o f B o m b a y H i g h b e g u n t h e g r o w t h o f M u m b a i region. From a small beginning Exploratory Bombay High with India’s first offshore Sagar-Samrat. ONGC has come a long way. After its success in Bombay High ONGC discovered various other fields in western offshore .Among the various discoveries in western offshore, South Basin proved to be one of the biggest gas fields in Asia. Total recoverable reserves are estimated to be of order of 200 billion cubic meters which is phenomenal when compared to such fields in the world. The exploration of basin field paved way for development of   units plants built with state of the art technology at a cost of Rs. 1300 crores and process of growth is continued. It has gas processing capacity of 41MMSCMD (Million Metric Standard Cubic Meter per Day). The whole Plant is completely automated where no one can find a single person working in the f ie ld a rea . This fu l ly automated p lant i s mainta ined and inspected regularly with the responsible group of people number of gas based industries in Gujarat and Northern India , cover ing

Delhi to br ing gas to shore and the process before it is distributed to consumers, ONGC had chosen a 625 hectares of l a n d i n H a z i r a p l a n t a b o u t 2 0 k m a w a y f r o m s u r a t t o w n w h i c h h a s n o w grown to gigantic complex sprawling in 705 hectares with following certain units plants built with state of the art technology at a cost of Rs. 1300 crores and process of growth is continued. It has gas processing capacity of 41MMSCMD (Million Metric Standard Cubic Meter per Day). The whole Plant is completely automated where no one can find a single person working in the f ie ld a rea . This fu l ly automated p lant i s mainta ined and inspected regularly with the responsible group of people units plants built with state of the art technology at a cost of Rs. 1300 crores and process of growth is continued. It has gas processing capacity of 41MMSCMD (Million Metric Standard Cubic Meter per Day). The whole Plant is completely automated where no one can find a single person working in the f ie ld a rea . This fu l ly automated p lant i s mainta ined and inspected regularly with the responsible group of people.

PRODUCTS:

1. SWEET NATURAL GAS

2. LPG (LIQUIFIED PETROLEUM GAS)

3. ARN (AROMATIC RICH NAPHTHA)

4. SKO (SUPERIOR KEROSENE OIL)

5. ATF (AVIATION TURBINE FUEL)

6. HSD (HIGH SPEED DIESEL)

7. HEAVY CUT

CUSTOMERS OF ONGC

1. KRIBHCO2. ESSAR

3. GAIL4. IOCL5. HPCL6. BPCL

DESPATCH OF PRODUCTS

1. RAIL

2. ROAD

3. PIPELINE

4. SHIP

PRODUCTS DISPATCHED

1. LPG – ROAD, PIPELINE, RAIL2. NAPHTHA – SHIP, PIPELINE, RAIL3.SKO – ROAD, PIPELINE4. SULPHUR – ROAD

• NATURAL GAS is sold to GAIL and marketing is done by GAIL.

• LPG is sold to IOCL, HPCL, BPCL and for domestic purpose.

• NAPHTHA is exported to Singapore, Hong Kong, South Korea, Japan etc through ship.

• SKO is sold to local customers as well as HSD also.

• ATF is used for internal purpose as well as HSD also.

• SULPHUR is sold to chemical companies. These all are the Value Added Products.

COMPETITORES OF ONGC

  1.ESSAR OIL

2.BPCL

3.HPCL

4.RIL

5.GPCL

6.IPCL

The main competitor of ONGC is Reliance Petrochemicals Ltd.

MAIN PLANT

1 . G A S T R U N K L I N E S2. GAS SWEETENING UNIT (GSU)3. DEW POINT DEPRESSION (DPD)4 . L P G R E C O V E R Y U N I T5. CONDENSATION FRACTIONATE UNIT (CFU)6. CAUSTIC WASH UNIT (CWU)7. GAS DEHYDRATION UNIT (GDU)8. KEROSENE RECOVERY UNIT (KRU)9. SULPHUR RECOVERY UNIT(SRU)

  MAIN UTILITIES AND OFFSITES

1. RAW WATER TREATMENT PLANT2. LPG STORAGE SPHERES3 . N G L S T O R A G E T A N K S4. NAPHTHA STORAGE TANKS5. KEROSENE STORAGE TANKS6. HSD/ATF STORAGE TANKS7. FIRE WATER STORAGE TANKS8. RAW WATER RESERVOIR.

GSU (GAS SWEETNING UNIT)

Purpose Of Gsu: To Remove Lethal Hydrogen Sulphide From Sour Gas.

Design Of Gsu: Sour Gas From Slug Catcher Is Distributed To Gsu Trains, Which

Comes In Counter Current Contact With Lean Amine Solution In Absorption Column.

The Rich Gas Leaves From Top Of The Column With 4ppm Hydrogen Sulphide.

It Is Then Routed To Gdu/Lpg Units.

The Rich Amine Enters The Regenerator Column For Regeneration And Recirculation In System.

Acid Gas Liberated From The Top Of The Regenerator Column During Recycling Of Methanoldiethylamine(Mdea) Forms Feed Of Sulphur Recovery Unit.

Mainly There Are 2 Process For Sweetning Of Sour Gas:1)Absorption2)Adsorption

1) Absorption:

Absorption Process Is Used To Remove A Component (Solute) From The Gas Stream By Contacting The Gas With A Liquid Solution(Solvent).

2) Adsorption: Adsorption Is The Process Of Removing Impurities From A Gas Stream By Means Of A Solid Material Called Adsorbent That Has Special Attraction For The Impurities.

In Amine Absorption Process,Mainly There Are 3 Types Of Amines:

1) Dea Is Much Less Corrosive To Carbon Steel Than Mea.2) Dea Is Less Volatile Than Mea.3) Dea Is More Reactive.

From The Above 3 Amines,Dea Is Selected.Reasons For Dea Selection Are Below:

4) Dea Is Much Less Corrosive To Carbon Steel Than Mea.5) Dea Is Less Volatile Than Mea.6) Dea Is More Reactive.

Dew Point Depression Unit (DPD)

The purpose is to remove hydrocarbon condensate from the sweetened and dehydrated gas by chilling to avoid hydrate formation in long distance H-B-J pipeline. The feed gas from GDU train is chilled to about (-) 5 deg.C in a chiller with the help of propane refrigerant in close circulation cycle. The cooled gas condensate is pumped to LPG plant for distillation. This treated gas is then sent to GAIL for onward transmission to H-B-J pipeline and partly to local consumars.

LPG PLANT:- A part of sweet gas from outlet of GSU (about 5 MMSCMD) and all the sweet condensate from DPD are taken as feed to LPG Recovery Unit. State-of-the-art cryogenic process using Turbo-Expander has been used for the first time in ONGC. The feed gas is first dried in molecular sieve dryers and then chilled in a Cold Box to (-)

300 C. The chilled vapor is expanded isentropically in Turbo-Expander wherein temperature of the gas falls to (-) 570 C. The heavier hydrocarbons (C 3+) get liquefied in the chilling process, which are separated for fractionation in LEF and LPG columns. The lean gas liberated from top of LEF column is further compressed as per requirement of downstream consumers. The products coming out from LPG column are LPG as a top product and Naphtha as a bottom product. A part of LPG is further distilled to obtained propane, which is used as a refrigerant in LPG and DPD unit.

LPG Spheres:-

The output from LPG stripper columns are generally LPG and other gases.This LPG is stored in large LPG spheres.This LPG is forced to the hight of the LPG spheres by pumps.

The design of the spheres are of spherical shape.There are 2 main reasons for it.

1. The inlet fire water from the top can be easily expanded as it enters the spheres. And is given for insulation process.

2. The stresses devloped on the sharp edges of other shapes like cubic shape, cylindrical shape etc, are hiher according to LAME’S Theorm . Whereas in

spherical shape there are no sharp edges which reduces the stress development.

The spheres are situated at several hights from ground because it causes sufficient presure different due to difference in height.

CONDENSATION FRACTIONATION UNIT(CFU):

This Unit at removal of H2S and recovery of LPG and NGL from the sour hydrocarbons condensate separated in the slog catcher. The liquid from Slug Catcher is distributed into stripper columns of various CFU trains. H2S is stripped from the condensate along with lighter hydrocarbons and fed to GSU trains for removal of H2S. The liquid from stripper bottom is fed to LPG column for recovery of LPG from the top and NGL from the bottom. The LPG is sent to Caustic Wash Unit for removal of H2S. The NGL forms the feed for KRU.

Product Specifications:LPG:

Case Case1 Case2 Case3 Case4

Pressure Kg/Cm2

 

Temp. o C

93.0

20.0

93.0

33.0

54.0

20.0

54.0

33.0

Component Mole

%

Kg

mol/hr

Mole

%

Kg

mol/hr

Mole

%

Kg

mol/hr

Mole

%

Kg

mol/hr

N2 - - - - - - - -

H2S 5 - 5.7 - 5.4 - 6.4 -

CO2 - - - - - - - -

C1 - - - - - - - -

C2 - - - - - - - -

C3 48.63 80.43 48.09 58.25 45.55 70.06 44.78 47.25

iC4 19.43 32.14 19.48 23.60 20.23 31.12 20.14 21.25

nC4 31.86 52.70 32.33 39.16 34.14 52.51 34.55 36.46

iC5 0.07 0.12 0.09 0.11 0.08 0.12 0.48 0.51

nC5 0.01 0.01 0.01 0.01 - - 0.05 0.06

C6 - - - - - - - -

Total 100.00 165.40 100.00 121.13 100.00 153.81 100.00 105.53

HC kg/hr 8487 6224 7959 5479

Mol. Wt. 51.31 51.38 51.74 51.98

Density kg/m3 528 528 528 529

Temp. o C 43 43 45 45

Press. kg/cm2 15.5 15.5 15.5 15.5

1. Vapour pressure at 65 oC (Max.)                      16.8 Kg/cm2

2. Total Volatile Sulphur PPM (Max.)                     20*

3. 95% distillate temp. at 760mm Hg                    2 oC

4. Copper strip corrosion (Max.)                           ASTM No.1 (Slight tarnish)

5. Dryness                                                                        No free water

6. Hydrogen Sulphide                                            20 ppm

* LPG shall be sweetened in the Caustic Wash Unit to meet IS-4576 specifications.

PROCESS DESIGN PROCESS DESCRIPTION Condensate Fractionation Unit is designed to remove H2S and to recover LPG & NGL from slug-catcher condensate.

The fractionation Unit consists of -Condensate receiving system-H2S Stripper-Condensate-Offgas compression-LPG Column.

 Condensate Receiving System The condensate as it comes from the slug-catcher is heated in a condensate preheater (E701) and received in Surge Drum (V701) under level control through LCVs LV1101

& LV1106. The preheater uses LP steam to heat the condensate upto 33  oC to 36 oC to avoid any hydrate formation. Hydrate formation is possible if there is high pressure drop across control valves.The flash vapour from the surge drum V701 is taken to gas sweetening unit directly (bypassing compressor) when condensate inlet pressure is at 80 kg/cm2 or more. Below 80 kg/cm2, the pressure is maintained 2 kg/cm2 belowthe inlet pressure in the surge drum to allow differential for incoming liquid and the vapour is routed through the compressor system.Any free water droplets get separated in the surge drum and collect in boot of V701. Water level is drained through interface level control mechanism. The condensate in the surge drum V701 is taken into Condensate Transfer pumps P701A/B (one operating & one stand by). This pump is provided to generate sufficient head & flow to avoid any condensate flashing in the down stream Filter-Coalescer X701A/B.Two unit of cartridge type Filter-Coalescer are provided (one operating & one stand by). The filtering elements of the filter are being used for filtering out any scale/dust/debris/Iron sulphides/black material which may entail during pre-commissioning/commissioning, pigging operation of the trunk lines.

 Condensate fractionation unit The coalescer element is used for removal of free water. The free water collected in the boot and is drained through interface level control mechanism. The condensate flows further through flow control valve FV1102 into the stripper column top tray. This is designed to maintain a back pressure to ensure that no flashing occurs in the filter chamber.Dew Point Depression Unit’s condensate can also be processed in CFU besides LPG plant as and when required so.

 H2S Stripper Stripper Column C701 is designed to strip off H2S from the sour condensate such that the condensate at the bottom reaches maximum of 4 ppm H2S and to retain maximum C3 & C4 in the condensate at pressure of 18 to 18.5 kg/cm2 at the prevailing inlet pressure.Feed to the stripper is a liquid at the upstream and flashes as liquid-vapour mixture in the space above the first tray of the column C701 of 61 valve type trays. The first 20 trays on the top section are single pass trays and the bottom section of 40 trays is double pass trays. The separated liquid trickles down the column and the vapour

escapes from the top as offgas. The Offgas Stripper bottom liquid is pumped through P703A/B pumps to reboiler E702 via basket type filters X702A/B to remove any suspended particles which may foul the reboiler. However, in view to conserve energy, these filter pumps were stopped on experimental basis to observe the satisfactory operation if possible without them running. Effectively, these pumps & filter assembly were bypassed since 1999.A kettle type reboiler E702 is provided at the Stripper C701 bottom whichutilizes MP steam for heating. Steam flow is controlled through FV201 to ensure stripping vapour at 135 to 145 oC& thereby maintain stripper bottom temperature at 93 to 97 oC.Bottom of C701 is sweet Condensate and is withdrawn from reboiler under level control cascaded with flow control valve FV202 to LPG Column C702

LPG Column

The stripper bottom liquid is taken to LPG column (C702) at 24th or 19th from top. This column has 60 trays and is designed to separate LPG (propane and butanes) from heavier components. The column operates at 9.7kg/cm2a pressure. This pressure has been chosen to keep overhead condensing temperature at 43 oC, so that cooling water can be used in the overhead condenser (E703).Reflux ratio from 1.5-2.0 is maintained in the column depending upon the operating case. Butane recovery of more than 99.55 % is achieved at design reflux. LPG is taken as overhead liquid product through the LPG reflux and transfer pumps (P702 A/B) under level control of reflux drum (V702).                                                             The column bottom has a thermo-siphon type reboiler (E704) using high pressure steam. Column bottom temperature varies from 175 to 185 oC depending upon operating case. NGL is withdrawn as bottom product and sent to Kerosene Recovery Unit for further processing or cooled to 45 oC by cooling water in NGL cooler E-705 and sent to storage in offsites as the case may be Most of Hydrogen sulfide (about 4 ppm) present in LPG column feed appears in LPG product resulting in 5 - 20 ppm concentrations. This LPG is sweetened in a caustic wash unit (Bubbling of LPG liquid in static bed of 15% caustic Soda solution) is off sites and sent to storage.

Off-gas Compression

The stripper overhead vapor is taken to compressor suction K.O.Drum (V703). The surge drum flashed vapor is also combined with this stream. Two numbers reciprocating compressors 701 A/B (one operating & one standby) are provided in phase-I, II, III to compress this sour gas and form the feed to gas sweetening units. The compressor discharge gas is cooled to 45 oC using cooling water in exchanger E706. Gas temperature is selected about 10 oC higher than dew point to avoid condensation

and production of sour condensate. This eliminates sour condensate recycle within the system. The cooled gas is sent to GSU through compressor discharge KOD drum V704. CFU off-gas compressor has been deleted for the Train 77 with the idea to utilize the existing under utilized compressor provided for this purpose under Phase I, Phase-II and Phase-III. CFU-off gas from this train shall be routed tothe common suction header of these compressors (the compressors have been integrated.). The deletion of CFU off gas compressors has necessitated a slight change in the control scheme of the stripper column and the compression circuit. In the earlier trains the compressors have been provided with a pressure control at the suction and the stripper column floats on the suction pressure of the compressor. In the present train the stripper column shall operate at a slightly higher pressure and its pressure control shall be independent of the suction pressure control of the existing compressor.

CAUSTIC WASH UNIT(CWU):-

The LPG from CFU contains up to 20 ppm H2S which has to be removed to less than the permissible limit of 4 ppm in CFU before it is sent for storage in Horton spheres. The LPG is passed through the absorber (containing caustic solution) and sand filter to wash and remove H2S. Make-up caustic lye is added for maintaining the quality of solution.

GDU (GAS DEHYDRATION UNIT)

Purpose of GDU:

To remove water vapors from sweet gas with the help of tri-ethylene glycol solution.

Design of GDU:

The purpose of a glycol dehydration unit is to remove water from natural gas and natural gas liquids.

When produced from a reservoir, natural gas usually contains a large amount of water and is typically completely saturated or at the water dew point. This water can cause several problems for downstream processes and equipment

. At low temperatures the water can either freeze in piping or, as is more commonly the case, form hydrates with CO2 and hydrocarbons (mainly methane hydrates).

Depending on composition, these hydrates can form at relatively high temperatures plugging equipment and piping.

 Glycol dehydration units depress the hydrate formation point of the gas through water removal.

Without dehydration, a free water phase (liquid water) could also drop out of the natural gas as it is either cooled or the pressure is lowered through equipment and piping. This free water phase will often contain some portions of acid gas (such as H2S and CO2) and can cause corrosion.

GLYCOL DEHYDRATION UNIT

DESIGN OF GLYCOL DEHYDRATION UNIT:

Process description:

Lean, water-free glycol (purity >99%) is fed to the top of an absorber (also known as a "glycol contactor") where it is contacted with the wet natural gas stream.

The glycol removes water from the natural gas by physical absorption and is carried out the bottom of the column.

Upon exiting the absorber, the glycol stream is often referred to as "rich glycol". The dry natural gas leaves the top of the absorption column and is fed either to a pipeline system or to a gas plant. Glycol absorbers can be either tray columns or packed columns.

After leaving the absorber, the rich glycol is fed to a flash vessel where hydrocarbon vapors are removed and any liquid hydrocarbons are skimmed from the glycol.

This step is necessary as the absorber is typically operated at high pressure and the pressure must be reduced before the regeneration step. Due to the composition of the rich glycol, a vapor phase having a high hydrocarbon content will form when the pressure is lowered.

After leaving the flash vessel, the rich glycol is heated in a cross-exchanger and fed to the stripper (also known as a regenerator). The glycol stripper consists of a column, an overhead condenser, and a reboiler. The glycol is thermally regenerated to remove excess water and regain the high glycol purity.

The hot, lean glycol is cooled by cross-exchange with rich glycol entering the stripper.

It is then fed to a lean pump where its pressure is elevated to that of the glycol absorber.

The lean solvent is cooled again with a trim cooler before being fed back into the absorber. This trim cooler can either be a cross-exchanger with the dry gas leaving the absorber or an air-cooled exchanger.

KEROSENE RECOVERY UNIT :- NGL produced from CFU is given value addition in KRU by way of producing aromatic rich naphtha (ARN), superior kerosene oil (SKO), heavy cut (HC) and/or high-speed diesel (HSD). The hot NGL is fed to Naphtha Column for distillation from where Naphtha is recovered as a top product. The bottom stream is fed to the Kerosene column through the gas fired furnace for further fractionation .Kerosene/ ATF is recorded from top of the Kerosene Column and HSD/ Heavy Cut is recovered from the bottom. A suitable chemical additive is added in ATF to maintain electrical conductivity, and storage stabilizer for HSD before these products are sent to storage.

SULPHUR RECOVERY UNIT The purpose is to convert acid gas liberated from GSU into elemental sulphur for environment protection.

Acid gas comes into contact with catalyst LOCAT in Absorber/Oxidizer. Hydrogen Sulphide (H2S) is oxidize to elemental Sulphur in present of catalyst. Air is introduced into Absorber/Oxidizer for regeneration of catalyst. Sulphur slurry from the bottom of the vessel melted and pulletized upto 99% purity and sent for disposal in HDPE bags in the market.

The catalyst is recirculated in the system and make up chemicals are dozed to maintain the quality. the vent gases from the top of the Absorber/Oxidizer vessel containing CO2,N2,O2 and moisture are vented to atmosphere.

CO-GENERATION PLANT (COGEN)

INTRODUCTION:

Cogeneration means simultaneous generation both electrical and thermal energy by raising a single primary heat source, thereby increasing the overall efficiency of the plant. Cogeneration is one of the most powerful and effective energy conservation techniques. In industries like refineries, petrochemical, fertilizer, sugar etc, there is a requirement of both power and steam. LPG/CSU plant at Uran needs power and steam. To meet this requirement a cogeneration plant was setup. Hence this plant fulfills the requirement of both electrical power and steam at a very low cost and high efficiency and reliability.

Cogeneration is of two types namely

Copping up cycle Bottom up cycle

Copping cycle is one of in which heat requirement is attained by externally firing the fuel. Whereas in bottom up cycle the heat requirement is fulfilled by internal chemical reactions this cycle is used in medicine production. Cogeneration plant at ONGC Uran is based on copping up cycle. The principle of this plant is mentioned below:

PRINCIPLE:

 Air from atmosphere is taken through an air filter and compressed in axial flow compressor driven by the turbine. The compressor air enters into combustion chamber where It is mixed with fuel (lean gas). During combustion its temperature increases at constant pressure (process B to C) then it expands mechanical energy by

rotating the turbine. A major part of this energy is available for the generator. Hence the thermal efficiency of the generator is very low Diesel engine is used for initial cranking of the system. Once the turbine attains the speed the contact is broken. However only 30% of the compressed air is used for combustion and

energy conversion and the rest of the air is used for cooling and sealing of the net bas path (Turbine blades nozzles etc). The efficiency of the turbine can be increased if the metallurgical part of the nozzle and blades are improved so that the size of the compressor can be reduced for the same turbine

What is Cogeneration?

Cogeneration is the process whereby a single fuel source, such as natural gas, is used to produce both electrical and thermal energy. By definition, an onsite cogeneration system is more efficient than a utility operated central power plant since thermal energy that would otherwise be wasted is captured for use at the facility. The result is a much more efficient use of fuel which can generate substantial savings for the end user. Conventional electrical generation by a utility central plant is only about 35% efficient compared to the 90% efficiency of an Intelligent Cogeneration Unit by IPS.

Because Intelligen Power Systems cogeneration equipment is so efficient, most installations deliver significant energy cost savings.

If your facility has a need for thermal energy, in the form of heating and/or cooling, you are a good candidate for a cogeneration system. Intelligen cogeneration systems can provide Electricity, Cooling, Heating, Hot water or Steam.

An Intelligen cogeneration system uses less fuel to produce the same amount of energy -saving money and helping to protect the environment

Some Facts about Efficiency:A typical facility will purchase electricity from the utility and fuel (gas or oil) to power a boiler for hot water and heating. This process is inefficient and expensive when compared to producing electrical and thermal energies onsite through cogeneration with Intelligen Power Systems.

Transmitting power from a central power plant across long distances carries the unfortunate price of a significant waste of power. By the time electricity reaches your facility, much of the energy used to produce the electricity is wasted. Electricity sent over the utility grid is generally between 25% and 35% efficient - which means that as much as 75% of the energy used by the utility to generate and transmit electricity is lost before it even gets to you. By definition, this inefficiency flows through to you as a customer in the form of higher electric rates.

An existing hot water heater (boiler) is typically anywhere from 50% to 80% efficient, which wastes as much as one-half of the input fuel.

The poor overall efficiency of separate electric and thermal energy production is bad news for the environment and for your profitability.

The good news is that Intelligen Power Systems equipment provides electricity and hot water at a combined efficiency that approaches 90%.

Electricity created right where it is used, at your facility, has no detrimental power line loss. More importantly, exhaust heat is recovered and provided to your facility as useable energy. Overall, the process is more efficient, which leads to savings for you, and the environment.

Depending on your circumstances, your savings can be substantial compared to the conventional methods of meeting your energy needs.

Layout Diagram of the Co-Generation Plant

 

Power capacity of the gas turbine (GT):Power- 3*19.6 MW

GE frame- 5 gas turbines

Steam capacity of the waste heat recovery boilers (HRSG):Steam- 2*75+1*90 TON/HRWaste heat recovery boilers

Plant demand for power and steam:Power average - 41.0 MW/HRPower (peak) - 50.0 MW/HR

Steam - 150 TON/HRExport (with 3 GTS) - 5.0 MW/HR

Import (with 3 GTS) – NILThis power and steam demand is easily met by the Co-generation plant as the power turbines produce 3*19.6 MW= 58.8 MWThe steam produced by the HRSG is 2*75+1*90 TON/HR = 240 TON/HR  But sometimes one of the gas turbine may not be operational as mechanical failure may occur, fuel gas line may leak, seizure of the compressor of the turbine etc. The Co-generation plant is always connected to the power grid MSEB in the case of failure of one of the turbines. Thus undisturbed power supply continues

Electric power to all the facilities and township at Hazira is supplied by cogeneration power plant through three gas turbine generators. These turbines are based on total energy conservation concept. The heat energy of gas turbine exhausts is used for generation of high, medium and low pressure steam for use in various process units. Excess power from the plant is wheeled to GEB grid for revenue generation.

How Cogen Works:

1. Two natural gas-fired combustion turbines drive generators to produce electricity.

2. The hot combustion gases from each turbine pass through a corresponding heat-recovery steam generator (HRSG) to produce steam. The HRSGs contain duct burners to produce additional steam as needed.

3. The high- and low-pressure steam from the HRSGs passes through a single extracting/condensing steam turbine that sends heating steam to the UW and produces electricity for the Madison area.

4. The exhaust steam is sent to a condenser and then cooled by cooling towers. This process forms water that is reused.

5. Centrifugal chillers provide 20,000 tons of chilled-water capacity. Electric-driven chillers use roof-mounted cooling towers for heat rejection.

6. The steam heat and chilled water is used on the UW-Madison campus.

7. The electricity is sent to an adjacent substation and then to the Madison area.

Cogeneration & CHPCogeneration (cogen) through combined heat and power (CHP) is the simultaneous production of electricity with the recovery and utilization heat. Cogeneration is a highly efficient form of energy conversion and it can achieve primary energy savings of approximately 40% by compared to the separate purchase of electricity from the national electricity grid and a gas boiler for onsite heating. Combined heat and power plants are typically embedded close to the end user and therefore help reduce transportation and distribution losses, improving the overall performance of the electricity transmission and distribution network (see district energy for more details). For power users where security of supply is an important factor for their selection of power production equipment and gas is abundant, gas-based cogeneration systems are ideally suited as captive power plants (i.e. power plants located at site of use).

Benefits of Gas Engine CHP

The high efficiency of a CHP plant compared with conventional bought in electricity and site-produced heat provides a number of benefits including

On site production of power Reduced energy costs Reduction in emissions compared to conventional electrical generators and

onsite boilers Heat Sources from a Gas Engine

The heat from the generator is available in from 5 key areas:

1. Engine jacket cooling water2. Engine lubrication oil cooling3. First stage air intake intercooler4. Engine exhaust gases5. Engine generator radiated heat, second stage intercooler

1, 2 and 3 are recoverable in the form of hot water, typically on a 70/90˚C flow return basis and can be interfaced with the site at a plate heat exchanger.

The engine exhaust gases typically leave the engine at between 400 and 500˚C. This can be used directly for drying, in a waste heat boiler to generate steam, or via an exhaust gas heat exchanger combining with the heat from the cooling circuits. 5. The heat from the second stage intercooler is also available for recovery as a lower

grade heat. Alternatively new technologies are available for the conversion of heat to further electricity, such as the Organic Rankine Cycle Engine.

CHP applications

A variety of different fuels can be used to facilitate cogeneration. In gas engine applications CHP equipment is typically applied to natural gas (commercial, residential and industrial applications), biogas and coal gas applications.

CHP System Efficiency

Gas engine combined heat and power systems are measured based upon the efficiency of conversion of the fuel gas to useful outputs. The diagram below illustrates this concept.

Firstly the energy in the fuel gas input is converted into mechanical energy via the combustion of the gas in the engine’s cylinders and their resulting action in the turning of the engine’s crankshaft.  This mechanical energy is in turn used to turn the engine’s alternator in order to produce electricity. There is a small amount of inherent loss in this process and in this example the electrical efficiency of the engine is 40% (in reality GE Jenbacher gas engines are typically between 40-48.7% electrically efficient).

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