A PROJECT REPORT ON

INDIAN OIL CORPORATION LIMITED,

PANIPAT

SUBMITTED BY:

PUSHPENDRA KUMAR (I.T. G.G.V., BILASPUR)

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ACKNOWLEDGEMENT

We take this opportunity to express a deep sense of gratitude to Mr Ajay Gupta, Mr Rajeev Ranjan, & Mr Kushal Chaudhary for their cordial support, valuable information and guidance, which helped us in completing this task through various stages.

We also take this opportunity to express our profound gratitude and deep regards to our guide Mr. Asheesh Chaturvedi and Mr. M. Sharma for their exemplary guidance, monitoring and constant encouragement throughout the course of this training. Their blessing, help and guidance given by them time to time shall carry us a long way in the journey of life on which our about to embark.

We would also like to thank sanjeev sir, saurabh sir, prashant sir, satyabrata sir, chandrabhan sir, viman sir, Ekta mam, kanhaiya lal sir for their guidance in field visits.

 We are obliged to staff members of IOCL for the valuable information provided by them in their respective fields. We are grateful for their cooperation during the period of our assignment.

 Lastly, we thank almighty, our parents, brother, sisters and friends for their constant encouragement without which this assignment would not be possible.

 

 

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CERTIFICATE

This is to certify that the project work entitled “Design of heat exchanger 13-E-5718” is a bonafide work carried out by Jyoti Ranjan Paikaray, Gyanendra Pratap Chhotray & Pushpendra Kumar under our guidance and direction.

To the best of our knowledge and belief the report

Embodies the work of the candidate

Has duly been completed

Fulfils the requirement

This project is the record of authentic work carried out during the period of May 19th to June 16th, 2014.

Mr. Asheesh chaturvedi Mr. Mrinmoy Sharma

Mr. Kushal Choudhary

Mr. Rajeev Ranjan

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INDIAN OILCORPORATION LIMITED

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INTRODUCTIONIndian Oil Corporation Limited, or Indian Oil, is an Indian state-owned oil and gas corporation with its headquarters in New Delhi, India. It is one of the sevenMaharatna status companies of India, apart from Coal India Limited, NTPC Limited, Oil and Natural Gas Corporation, Steel Authority of India Limited, Bharat Heavy Electricals Limited and Gas Authority of India Limited It is the world's 83rd largest corporation, according to the Fortune Global 500 list, and the largest public corporation in India when ranked by revenue.

Indian Oil began operations in 1959 as Indian Oil Company Ltd. The Indian Oil Corporation was formed in 1964, with the merger of Indian Refineries Ltd.Indian Oil and its subsidiaries account for a 49% share in the petroleum products market, 31% share in refining capacity and 67% downstream sector pipelines capacity in India. The Indian oil Group of companies owns and operates 10 of India's 22 refineries with a combined refining capacity of 65.7 million metric tonnes per year. In FY 2012 IOCL sold 75.66 million tonnes of petroleum products and reported a PBT of 37.54 billion, and the Government of India earned an excise duty of 232.53 billion and tax of 10.68 billion.The company is mainly controlled by Government of India which owns approx. 79% shares in the company.

Indian oil is the highest ranked Indian company in the Fortune Global 500 listing, at the 88th position in 2013. It is also the 18th largest petroleum company in the world and the No. 1 petroleum trading company among the national oil companies in the Asia-Pacific region. IOCL was featured on the 2011 Forbes Global 2000 at position 243.

It is the fifth most valued brand in India according to an annual survey conducted by Brand Finance and The Economic Times in 2010.

IOCL has various refineries across India.

In Assam

1.Digboi Refinery is India's oldest refinery and was commissioned in 1901. Originally a part of Assam Oil Company, it became part of Indian oil in 1981. Its original refining capacity had been 0.5 MMTPA since 1901. Modernisation project of this refinery was completed by 1996 and the refinery now has an enhanced capacity of 0.65 MMTPA. UOP licensed the technology for the Coking process in this refinery.

2.Guwahati Refinery, the first public sector refinery of the country, was built with Romanian collaboration and was inaugurated on 1 January 1962. Its capacity is 1 MMTPA.

3.Bongaigaon Refinery became the eighth refinery of Indian oil after merger of Bongaigaon Refinery & Petrochemicals Limited w.e.f. 25 March 2009. It is located at Dhaligaon in Chirang district of Assam, 200 km west of Guwahati.

In Bihar: Barauni Refinery, in Bihar, was built in collaboration with Russia and Romania. It was commissioned in 1964 with a capacity of 1 MMTPA. Its current capacity is 6 MMTPA.

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In Gujarat: Gujarat Refinery, at Koyali (near Vadodara) in Gujarat, is Indian oil’s second largest refinery. The refinery was commissioned in 1965. It also houses the first hydrocracking unit of the country. Its present capacity is 13.70 MMTPA.

In West Bengal: Haldia Refinery is the only coastal refinery of the Corporation, situated 136 km downstream of Kolkata in the PurbaMedinipur (East Midnapore) district. It was commissioned in 1975 with a capacity of 2.5 MMTPA, which has since been increased to 7.5 MMTPA.

In Uttar Pradesh: Mathura Refinery was commissioned in 1982 as the sixth refinery in the fold of Indian oil and with an original capacity of 6.0 MMTPA. Located strategically between Delhi and Agra, the capacity of Mathura refinery has been increased to 8.8 MMTPA.

In Haryana: Panipat Refinery is the seventh and largest refinery of Indian oil. The original refinery with 6 MMTPA capacity was built and commissioned in 1998. Panipat Refinery has since expanded its refining capacity to 12 MMTPA. There are plans to further expand the capacity to 21 MMTPA.[7]

In Odisha (Orissa): Paradip Refinery - The commissioning of 15 million tonnes per annum refinery in November 2012 has been delayed and is now expected to be operational only in September 2013.[8]

The main products of Indian oil are petrol, diesel, LPG, auto LPG, aviation turbine fuel, lubricants and petrochemicals: naphtha, bitumen, kerosene etc.

Indian oil operates the largest and the widest network of fuel stations in the country, numbering about 20,575 (16,350 regular ROs & 4,225 KisanSeva Kendra). It has also started Auto LPG Dispensing Stations (ALDS). It supplies Indane cooking gas to over 66.8 million households through a network of 5,934 Indane distributors.

Brands:

Indane Gas - Domestic and Industrial Gas AutoGas - Automotive Natural Gas

Xtra Premium - Automotive Premium Petrol

Xtra Mile - Automotive Premium Diesel

Servo - Lubricants and Greases

Propel - Petrochemicals

Indian oil Aviation - Aviation fuel

LNG at Doorstep - LNG by cryogenic transportation

The main services offered by Indian oil are Refining, Marketing, Pipelines, R&D and Training. Indian oil's Research and Development Center (R&D) at Faridabad supports, develops and provides the necessary technology solutions to the operating divisions of the corporation and its customers within the country and abroad.

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IOCL-PANIPAT

Panipat Refinery is the seventh refinery of Indian Oil. It is located in the historic district of Panipat in the state of Haryana and is about 23 km from Panipat City. The original refinery with 6 MMTPA capacity was built and commissioned in 1998 at a cost of Rs. 3868 crore (which includes Marketing & Pipelines installations).

The major secondary processing units of the Refinery include Catalytic Reforming Unit, Once Through Hydrocracker unit, Resid Fluidised Catalytic Cracking unit, Visbreaker unit, Bitumen blowing unit, Sulphur block and associated Auxiliary facilities. In order to improve diesel quality, a Diesel Hydro Desulphurisation Unit (DHDS) was subsequently commissioned in 1999.

Referred as one of India’s most modern refineries, Panipat Refinery was built using global technologies from IFP France; Haldor-Topsoe, Denmark; UNOCAL/UOP, USA; and Stone &Webster, USA. It processes a wide range of both indigenous and imported grades of crude oil. It receives crude from Vadinar through the 1370 km long Salaya-Mathura Pipeline which also supplies crude to Koyali and Mathura Refineries of Indian Oil.

Petroleum products are transported through various modes like rail, road as well as environment-friendly pipelines. The Refinery caters to the high-consumption demand centres in North-Western India including the States of Haryana, Punjab, J &K, Himachal, Chandigarh, Uttaranchal, as well as parts of Rajasthan and Delhi.

The LPG produced from the refinery is pumped through a dedicated pipeline to IndianOil’s Kohand bottling plant where bottling and bulk despatches are done. Panipat Refinery has also developed new products like 96 RON petrol, and sub-Zero diesel for the Indian army. It is already operating above 100% capacity for the last four years.

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NAPHTHA CRACKING UNITNaphtha cracking unit is the mother unit of the entire Naphtha cracker complex. In NCU, low aromatic naphtha cracks into lighter hydrocarbons in cracking heaters, which are then individually separated by fractionation to produce mainly polymer grade ethylene and polymer grade propylene. Ethane and propane produced in the process are recycled back to cracking heaters.

WHAT IS CRACKING???Cracking is a process to break large molecules of hydrocarbons into smaller ones by

heating. It may be carried out in 3 ways Catalytic, hydrocracking & Thermal cracking. Thermal cracking is the process of cracking naphtha into ethylene and propylene.

Steam is used as a diluent to inhibit coking in the tubes and to increase the percentage of Ethylene. Low molecular wt. Feedstock such as ethane and propane give a higher percentage of ethylene whereas high molecular wt. Feedsock such as naphtha and gas oil is used if propylene is required in significant qty.

HEATER SECTION

Naphtha and C4, C5, C6 recycles from associated units are fedto the short residence time(SRT VI) liquid cracking heaters where naphtha and C4, C5, C6 recycle feeds get cracked. There are six such SRT VI heaters out of which 5 are normally in operation. There is one SRT III gas cracking heater where ethane & propane recycles are cracked. Two SRT VI

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heaters can also be operated as SRT III heater when the regulator SRT III heater is under decoking/maintenance. Dilution steam is added to each of these coils to reduce coke deposition. There are six transfer line exchangers (TLE) per heater, which reduce the temp of cracked products drastically within a fraction of seconds. The heat recovered by cooling is used to generate super high pressure (SHP) steam at a temp of 525 OC.

The effluent from SRT VI heater is routed to Gasoline Fractionators after oil quenching. Effluent from SRT III heater is partly routed to Quench tower and balance to PFO stripper. All the SRT VI and SRT III heaters operate using fuel gas only. The primary fuel gas is methane rich offgas produced in NCU. Makeup fuel is C3/C4 LPG supplied from refinery or RLNG vapour.

GASOLINE FRACTIONATION AND CHARGE GAS QUENCHINGThe heater effluent from SRT VI heater is further cooled in gasoline fractionators. Gasoline and lighters are taken out as an overhead vapour and sent to Quench tower. The fractionator bottom is PyrolysisFuel Oil(PFO) which is sent to the PFO stripper having two stripping sections. Top section uses part of SRT III effluent( components boiling between 280-370 OC is stripped out) and the bottom section uses LP steam for stripping.

Pyrolysis Gas Oil (PGO) is drawn from the fractionator as a side stream and after steam stripping in PGO strippe it is sent partly as purge oil for instrumentation and the rest is blended with PFO and sent to OSBL storage.

Gasoline fractionator overhead and part of SRT III heater effluent enter the quench tower where the gase are partially condensed by direct countercurrent contact with recirculating water . The Quench tower overhead is sent to charge gas compressor while the water and condensed gasoline is sent to the quench water settler for gasoline separation. Part of gasoline from settler is sent back to gasoline fractionators as reflux and the balance is sent to gasoline stripper.

PROCESS WATER STRIPPING AND DILUTION STEAM GENERATIONThe water from Quench water settler is sent to process water stripper which is stripped with live dilution steam and LP steam to the bottom of tower, to remove acid gases and volatile hydrocarbons. The vapour leaving process water stripper is sent to quench tower. The water from stripper bottom isused for steam generation against circulating quench oil and medium pressure steam in Dilution steam drum. Provisions for dilute caustic injection to dilution steam drum feed, process water stripper feed and quench tower bottoms are provided for pH control. To prevent a build-up of non-volatiles, a blowdown stream from

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the dilution steam drum is drawn, cooled to 40 OC against cooling water and sent to OSBL, waste treatment facility.

CHARGE GAS COMPRESSION, GASOLINE AND CONDENSATE STRIPPINGThe Quench tower overhead vapors are compressed from 0.47 to 38.67 kg/cm2g in a 5-stage centrifugal compressor with interstage cooling to about 40 OC. Between the third and fourth stages, the charge gas is treated by amine caustic/water wash to remove acid gases generated in the cracking heaters. Spent caustic from the caustic/water wash to remove acid gases generated in the cracking heaters. Spent caustic from the caustic tower is washed with gasoline and sent to OSBL spent caustic treatment facility. The condensate from the third stage discharge drum is recycled to third stage suction drum; the condensate from the third stage suction drum is recycled back to the second stage suction drum where hydrocarbon and water separation takes place. Water condensed in the second stage suction drum is recycled to first stage suction drum and then pumped to the quench tower. Hydrocarbon condensed in the second stage suction drum is sent to the gasoline stripper which operates just above the 1st stage suction drum pressure.

The 5th stage discharge after water cooling is sent to the 5th stage suction drum. The vapor is cooled further by reheating lower deethanizer feed and then by two levels of propylene refrigerant to 15.6 OC. The partially condensed liquid/vapour mixture flows to the dryer feed drum.

The condensate stripper operates just above the 4th stage suction drum pressure. In the condensate stripper, the hydrocarbon is stripped of ethane and lighter materials by the vapor generated by a steam heated reboiler. The stripper bottoms are cooled against cooling water and sent to condensate stripper bottoms filter. The dried stripper bottoms is sent to depropanizer.

ACID GAS REMOVALCharge gas from the 3rd stage of charge gas compressor is heated against QW to about 45 OC and then fed to the bottom section of Mono Ethanol Amine(MEA) acid gas absorber. Superheated charge gas shall be introduced to acid gas absorber to avoid HC condensation. Lean MEA coming from regenerator is introduced to middle of absorber. Charge gas contacts with lean MEA by counter current flow. MEA absorbs both H2S and CO2 in charge gas. The rich MEA is sent to gasoline wash column. Treated charge gas flows to water wash stripper at absorber top. Charge gas contacts with water to remove entrained MEA. Water from regenerator reflux drum is introduced to top of absorber, then, returned to regenerator reflux drum.

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SPENT CAUSTIC PRE-TREATMENTThe spent caustic solution contains sodium carbonate, sodium sulphide and small percentage of NaOH. The dispersed hydrocarbons in the spent caustic may cause considerable fouling in the downstream OSBL treating unit and are therefore removed with a gasoline wash. Spent caustic from the caustic tower is mixed with wash gasoline from gasoline stripper in the feed line to the spent caustic coalescer. The spent caustic is degassed, and spent gasoline mixed with wash water drawn from dilution steam generator. After separation, the spent gasoline is returned to the quench tower. The gasoline washed spent caustic from the spent caustic coalescer is sent to OSBL for further treatment.

CHARGE GAS DRYING AND CHILLINGThe charge gas at 15.5 OC from the dryer feed drum is dried in a two-bed molecular sieve drying system. One bed is on stream while the other bed is being regenerated in a cyclic operation. Methane offgas from the recovery section is heated by high pressure steam and used to regenerate the desiccant. The regeneration gas is cooled and sent to the regeneration gas K.O. drum for removal of water prior to entering the fuel gas system. Any condensed water from the regeneration gas K.O. drum is returned to the quench tower. The charge gas is then progressively chilled to -72 OC by both processes and refrigerant cooling. The charge gas from the demethanizer feed separator no.1is further chilled to -97 OC. The condensate is separated in separator no.2 and sent to the demethanizer as feed.

The charge gas demethaniser feed separator no. 2 is finally chilled to -131 oC. The condensate is separated in demethaniser feed separator no. 3 and sent to demethaniser as feed no.4. The residual is hydrogen of approximately 75% purity, which is further upgraded by removal of methane in a 2-stage Joule-Thompson expansion method.

DEMETHANISERThe condensed liquid from the charge gas chilling train along with the vent gas from ethylene fractionation and light gas recycle from polypropylene plant are sent to the appropriate feed location of the demethaniser. Provision for reprocessing off spec ethylene is also provided in the demethaniser. The bottom product is reheated against ethylene and propylene refrigerant in the cold box, after which it is split into 2 streams. The methane refrigeration is condensed by the lowest level ethylene refrigeration. The system provides liquid methane as reflux to the tower. The over head of DM is split into 2 streams, one stream is mixed with reflux drum liquid. The other stream is heated and compressed. Part of liquid from the reflux drum is sent to DM as reflux. The remainderof reflux is mixed with DM overhead and sent to cold box as methane refrigerant.

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METHANATION AND HYDROGEN DRYINGRaw hydrogen generated in hydrogen-methane separator no.2 goes to methanator reactor and CO to methane and water in presence of hydrogen. Methanator reactor effluent is progressively cooled to about 18.6 oC. Condensed water is separated in the hydrogen dryer K.O. drum. The hydrogen leaving drum goes to hydrogen dryer for water removal. Dry hydrogen source from hydrogen dryer is used in acetylene, MADP, C4 hydrogenation and pyrolysis gasoline hydrogenation reactors. Excess hydrogen, if any, is sent as product to refinery hydrogen header. Condensate is sent from hydrogen dryer KO drum to quench tower.

DE-ETHANISATION, ACETYLENE HYDROGENATION AND ETHYLENE FRACTIONATIONThe demethaniser bottom products which is split into 2 streams, feeds the deethaniser to separate c2 from c3+ material.Deethaniser overhead is partially condensed and collected in reflux drum. Deethaniser also processes treated FCC dry c2 and FCC c3 stream received from refinery. A 2- bed acetylene converter having silver promoted palladium catalyst for selective hydrogenation of acetylene to ethylene and ethane.

During hydrogenation, a small portion of aetylene is converted to a polymer called green oil. A slipstream of ethylene/ethane, is taken as a side draw from ethylene fractionators, is mixed with the converter effluent prior toexiting the cr green oil KO drum. KO drum bottoms liquid, containing the green oil is recycled back to the Deethaniser. The overhead vapour from c2 green oil KO drum passes to the ethylene fractionators via the ethylene dryer. Fractionator overhead is condensed by ethylene refrigerant. The ethylene product is withdrawn as a sidedraws from the tower and sent to the ethylene product surge drum. Vent gas from the reflux drum is recycled back to deethaniser.

The ethylene product is withdrawn as a sidedraws from the tower and sent to the ethylene product surge drum. From the surge drum, we get ethylene product as follows:

One stream is chilled against ethylene refrigeration in successin to -98 oC and routed to low pressure cryogenic storage.

Second stream is pumped and heated against liquid propylene and delivered as ethylene product vapour at 28 kg/cm2g and 30oC to downstream polymer units.

Third stream is pumped and heated against ethylene product vapour product at 52 kg/cm2g and 30oC to downstream polymer units.

Ethane is withdrawn from ethylene fractionators bottoms and recycled to SRT III heater after vaporisation and heating.

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DEPROPANISERDeethanizer bottoms and condensate stripper bottoms are the feed to depropaniser to separate C3 components stripper bottom from C4 and heavier components, after condensate is used as flux and balance is fed to Methyl acetylene and Propadiene converter. Depropanizer bottom product containing C4 and heavier material is sent as debutanizer feed.

MAPD HYDROGENATIONIn this section methyl acetylene (MA) and Propadiene (PD) present in the depropaniser overhead are removed by selective hydrogenation to propylene and propane in a single bed MAPD reactor containing Sub- Chemie G-681 IX hydrogenation catalyst.

Reactor feed stream combined with recycle liquid from <APD converter effluent separate vapour leaving the separator, is cooled and returned to charge gas compressor to recover H2, CH4 and C3 hydrocarbons. Part of liquid from the separator drum is combined with C3 recycle from PP Plant and sent to the propylene fractionator-2.

PROPYLENE FRACTIONATORThe Propylene Fractionator uses a two tower system to separate the feed into polymer grade propylene and propane.

The Polymer grade Propylene product is withdrawn as a side draw from tower2 and delivered to OSBL downstream polymer plant. A portion of side draw product can be chilled and routed to low pressure OSBL cryogenic storage at -450C.

Bottoms from tower 2 are fed to tower 1. The propane rich product is withdrawn from tower 1 bottom and sent to the propane recycle drum. The recycle is vaporized and mixed with ethane recycle before entering into SRT-III Cracking heater.

DEBUTANIZERDepropanizer bottom flows to the debutanizer where the raw C4 product is separated, the debutanizer overhead product consisting of mixed C4s, which is pumped to butadiene extraction unit or C4 hydrogenation unit.

Debutanizer bottom is combined with gasoline from gasoline stripper and sent PGHU for hydrogenation.

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Naptha Cracker Associated Unit (NCAU)

It consists of following four units-

C4 Hydrogenation Unit (C4HU) Benzene Extraction Unit (BEU) Pyrolisis Gasoline Hydrogenation Unit (PGHU) 1,3- Butadiene Extraction Unit (BDEU)

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C4 Hydrogenation Unit (C4HU):

This unit is designed to partially hydrogenated the raw mixed C4, When Butadiene unit is not opeating. In this mode butadiene is fully saturated, but as catalyst is not selective a

portion of the olefins also saturate. The equipment in the C4HU is designed for upto 70% olefins saturation.

Process Flow Diagram of C4HU

C4 mix comes from Debutanizer overhead (60 MT/Hr) and hydrogen from methanator (1.53 MT/Hr), hdrogenated C4 LPG is forwaded to Heater and LPG Pool. In alteration operation, when BDEU is notoperating, C4HU will process raw C4mix. Butadiene and portion of butenes are hydrogenated in this mode of opertion.

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Pyrolisis Gasoline Hydrogenation Unit (PGHU):

PGHU processes raw pyrolysis gasoline from NCU in a two stage hydrogenting unit to produceC6 – C8heart cut i.e. sent to BEU for benzene recovery, a fully hydrogenated C5 cut i.e. recycycle to cracing heaters and a partially hydrogenated C9 cut.

Process Flow Diagram of PGHU

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Benzene Extraction Unit (BEU):

BEU recovers benzene from C6 – C8 cut from PGHU. Nonaromatics C stream is recycled to the NCU cracking heater and C7 – C8 cut sent to the storage as product in OSBL storage. It has a capacity of 129.88 KTA of benzene. 60 MT/ Hr C6 – C8 heart cut is fed to this unit.

Process Flow Diagram of BEU

1,3- Butadiene Extraction Unit (BDEU):

BDEU recovers 1,3 butadiene from the raw mixed C4 stream produced in in the NCU. BD Raffinate is sent to C4HU.

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PROJECT: DESIGN OF A SHELL AND TUBE HEAT EXCHANGER

Description: A heat exchanger has recently been installed to reduce the temp. of overhead products of a Dehexaniser column in Benzene extraction unit of NCAU. The heat exchanger is not actually designed as per the operating conditions and required conditions of the process. As a result, it is found that the exchanger is reducing the temp. Of overhead products as required but at the cost of increased pressure drop which is later accounting for difficulty in reflux back to the Dehexaniser column.

Objective: To design a shell and tube heat exchanger as per the operating conditions and reduce the pressure drop.

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Given data:

Temperature Flow rate (kg/s) Allocation

Process fluidInlet- T1- 740C 24 Shell Side

Outlet- T2- 450C 24

Cooling water Inlet- t1- 300C -- Tube Side

Outlet- t2- 400C --

Logarithmic Mean Temp difference =

Tln = = 23.220C

R = = 2.9 S= = 0.23

From Figure 12.19 (Coulson &Richardson) Ft = .93

Physical properties:(From Kern, Process Heat Transfer, McGraw-Hill)

Water, from steam tables: Process Fluid:Temperature, 0C 35 60Cp, kJ kg-1 0C-1 4.2 1.848K kW m-10C-1 625x10-6 150x10-6

Kg m-1 s-1 0.734x10-3 .512x10-3

Kg m-3 993.7 836

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Duty :

Oil flow-rate = 24 kg/s

Water flow-rate =

From Figure 12.1, for cooling tower water and low organic liquid, take

U=650 Wm-2C-1

Area required = m2

Tube-side coefficient:

Select 20 mm o.d., 16 mm i.d. tubes, 4 m long, triangular pitch 1.25do, carbon steel.

Surface area of one tube = 20 10_3 5 = 0.314 m2

Number of tubes required = say 296, even number

Cross-sectional area, one tube = -3)2 =2.011 10-3

Total tube area = -3 =595 10-4 m2

Put water through tube for ease of cleaning.

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Tube velocity, one pass =

For 2 pass Ut = 2 .5076 = 1.02 m/s

A floating head will be needed due to the temperature difference. Use a pull through type.Tube-side heat transfer coefficient

hi= 0C

Shell-side coefficient:Bundle diameter, Db

From Figure 12.10, for pull through head, clearance = 60 mm

Shell diameter, Ds mm

Use 25 per cent cut baffles, baffle arrangement for divided shell as shown below:

Baffle spacing as 1/5 shell diameter =

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Cross-flow area,As

Mass velocity, Gs

Equivalent diameter, de

Linear Velocity,us

Re

From figure 12.29(Coulson & Richardson’s),

jh= 2.8 10-3

Pr

hs m-2 0C-1

Overall coefficient:

Take fouling factors as 0.00025 for cooling tower water and 0.0002 for gas oil (light organic). Thermal conductivity for carbon steel tubes 45 Wm-2 0C-1

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.0002

Or .001219

Or U0 = 820 Wm -2 0 C -1

Well above the initial estimate of 500 Wm-2 0C-1, so design has adequate area for the duty required.

Pressure drops:

Tube-side

Re

From Figure 12.24(Coulson & Richardson’s),

jf= 4 . Neglecting the viscosity correction

[ ]

i.e.

m-2 =0.68 kg cm -2

Shell-side

i.e.

, too high

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Pressure drop could be reduced by increasing the baffle pitch. Doubling the pitch halves the shell-side velocity, which reduces the pressure drop by a factor of approximately (0.5)2 and by increasing baffle space 4 times, pressure drop is,

This will reduce the shell-side heat-transfer coefficient by a factor of (0.5)0.8 (i.e. h0 Re0.8

)

ho= 2438 0C-1

This gives an overall coefficient of 680 W m-2 0C-1, still above assumed value of 650 Wm-2 0C-1.

(1-2 Shell & Tube Heat Exchanger)

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