SUMMER TRAINING REPORT

ON

AT

BABRALA(U.P.)

SUBMITTED BY:-

AMAN KR SINGHSerial No.-05/11Roll No.- 1104551004Final B.Tech. Chemical EngineeringH.B.T.I. KANPUR

CERTIFICATE

This is to certify that AMAN KR SINGH (Roll number:-1104551004), Student of Chemical Engineering Department, HBTI Kanpur has completed the summer training in urea department on the project entitled COMPARISON OF PRILLING TOWER ON THE ACTUAL AND DESIGN DATA under our guidance.He has a good appetite for learning. We wish success for his future.

Project head: - Mr. U.P Singh(Head of Department urea plant)

Project Guide:-Mr. Prabhat Srivastava (Manager Urea Department)

Mr. Siddharth

ACKNOWLEDGEMENT

Words are inadequate and out of place at times particularly in the context of expressing sincere feelings in the contribution of this work, is no more than a mere ritual. It is our privilege to acknowledge with respect & gratitude, the keen valuable and ever-available guidance rendered to us by Name and Designation of Training Guide/Mentor of industry without the wise counsel and able guidance, it would have been impossible to complete the training in this manner.I am always be highly grateful to Mr. U.P Singh, (Head of Department), and Mr. PrabhatSrivastava,(MANAGER)for providing this opportunity to carry out the present work. I would like to thank Mr. Siddharth for his appreciations that made me more enthusiastic in delivering my best efforts for completion of the project We express gratitude to other faculty members of Chemical Engineering Department, HBTIK for their intellectual support throughout the course of this work.Finally, we are indebted to our family and for their ever available help in accomplishing this task successfully. Above all we are thankful to the almighty god for giving strength to carry out the present work.

Name of Candidate :Aman Kr Singh

DECLARATION

I hereby declare that all the information mentioned in the project report is best to my knowledge; I have not submitted the same report in any other organization. All the findings are based on my own effort and research.

Aman Kr. Singh

CONTENTS

S.No.Name

1. Introduction to Company2. Fire & Safety Fire Prevention Classification of fire Firefighting gadgets & appliances Safety programme at T.C.L. 3. Urea Plant (Process Description)and functionof important sections.4. Project Objective Theory Various methods to make a finished product. 5. Calculations Diameter of the tower. Height of the tower.6. Results7. References8. Experience9. Scope for further improvement

1. INTRODUCTION TO TATA CHEMICALS LIMITED BABRALATata Group, India's foremost business conglomerate. Tata Chemicals, by itself, is one of the largest inorganic complexes in the world beginning to TATA Group. Its first plant, which is also called inaugurated establishment of TATA. It is India's leading manufacturer and marketer of inorganic chemicals and fertilizers, with a turnover of over Rs. 4000 crores and is part of the Rs 65,000-crore ($14.25 billion) TCL's products and production processes are benchmarked with the best of global touchstones, and meet the most rigorous international specifications., Established in 1939. An ISO-9001/14001 OHSAS 18001 certified company, TCL has a varied user industry base comprising glass, paper, textiles, food additives, petroleum, refining, chemicals, dyes, pesticides, direct farm application etc. The products go into numerous end-use applications in a variety of industries: glass, detergents, paper, textiles, agriculture, photography, pharmaceuticals, food, tanning, rayon, pulp, paints, building and construction, and chemicals.

Tata Chemicals is also one of India's leading manufacturers of urea and phosphatic fertilizers. With an export presence in South and Southeast Asia, the Middle East and Africa, it has set itself the objective of achieving global cost competitiveness in soda-ash. Its foray into phosphatic fertilizers follows the merger of Hind Lever Chemicals Limited into Tata Chemicals Limited. TCL's phosphatic fertilizer complex at Haldia in West Bengal is currently the only manufacturing unit for DAP/NPK complexes in West Bengal. The Haldia plant has production volumes exceeding 1.2 million tons per annum. Tata Chemicals makes urea at its fertilizer complex in Babrala. The complex has an installed capacity of 3500 MTPD, which constitutes nearly 12 per cent of the total urea produced by India's private sector. Tata Chemicals is among the world's largest producers of synthetic soda ash, with the largest domestic market share, produced at the company's integrated complex at Mithapur on the Gujarat coast in western India.

The fertilizers, sold under the brand name 'Paras', lead the market in West Bengal, Bihar and Jharkhand. TCL is also a pioneer and market leader in the branded, iodized salt segment. Its salt has a purity percentage of 99.8 per cent, the highest in the country.

CREDENTIALS OF TATA CHEMICALS LIMITED BABRALA AWARDS: Prestigious Industry Award, Govt. of UP., 1995. National Energy Conservation Award, Ministry of Power, 1997. National Energy Conservation Award, Ministry of Power, 1998. Best Production Performance Award for Nitrogenous Fertilizers, Fertilizers Association of India. Second best productivity performance in Nitrogenous Fertilizers Industry, 1997-98. YogyataPramanPatra Award, 1998. Jawaharlal Nehru memorial National Award for Pollution Control and Energy Conservation, 2000-01. Golden Peacock Environmental Management Award, World Environment Foundation, 2001-02. Best Technical Innovation Award, Fertilizer Association of India, Dec.2004. Excellence in Safety, Fertilizer Association of India, Dec.24. Commendation Certificate for Strong Commitment to TQM, CII-Exim Bank Award for Business Excellence, Nov.2004. 5 Star Rating in Safety, British Safety Council, UK, Safety Gold Awards, Greentech Foundation, Delhi. Indian Chemical Council (ICC) confers the ICC award for social responsibility 2005-06. NSCI safety award for 2006. ICC Aditya Birla Award for Best Responsible Care Committed Company and ICC Award for Social Responsibility for 2005-06. Fertilizers Association of India Award for the Best Technical Innovation 2007. Nine ABCI (Association of Business Communicators of India) Awards, 2008.

TCL BABRALA: THE NATIONS CONCEIT Substituting a part of the imports of Urea, TCL, Babrala is estimated to save the country about Rs. 500 crores in foreign exchange every year and provide the farmer with nitrogenous nutrient, which could help raise the food production by about 4 million tones/year. First major steps towards the fulfillment of a long standing TATA CHEMICALS commitment to provide the farmer with an optimal package of agriculture inputs to safe guard the food security of the company. Produced more than 100% of the designated production during the first year of commercial production. Produced more than 8, 40,102.35 tons of Urea achieving a capacity of 113% in the year1995-96, and produced 9, 51,764 tons of Nitrogenous Urea in year 1996-97. Now produce capacity of 8, 64,000 tons of Urea per year, which constitutes nearly 12 per cent of the total urea produced by India's private sector. Total production of urea at Babrala is 3575 tons/day maximum and 3500 tons/day average. Current maximum capacity is 101%. The Babrala facility, among the best of its kind in India and comparable to the best in the world, has set new standards in technology, energy conservation, productivity and safety It is the only fertilizer plant in the country to use dual feedstock: natural gas or naphtha, or a combination of both.

MILESTONES OF TATA CHEMICALS LIMITED, BABRALA

Commercial Production Started onDecember 21, 1994

AMMONIA UNIT

First firing of Reformer Furnace for dry out of refractoryOctober 12, 1994

First feed into Primary ReformerOctober 20, 1994

First Carbon Dioxide for making UreaOctober 23, 1994

First Ammonia productionNovember 14, 1994

UREA UNIT

Urea Prill Test conductedOctober 04, 1994

First Prill Test conducted through Unit 2November 05, 1994

Second Prill Test conducted through Unit 2December 09, 1994

ISO 14001 certificate obtained in October 2000.

ISO 14001 certificate for Babrala township obtained in 2004.

COMPOSITION OF TATA CHEMICALS LIMITED, BABRALA

1.0Ammonia Plant

Capacity: 2000MTPD Technology: HALDOR TOPSE Process, DENMARK Plant (Single Stream) Production: 2000tons/day of liquid Ammonia. After de-bottlenecking Plant at TCL, Babrala is the first low energy plant in the country.

Basic scheme involves the following steps:

Desulphurization. Primary, Secondary Reforming and fired heater Carbon Dioxide Shift. Methanation. Synthesis and Chilling. Storage and supply to Urea unit

2.Urea Plant

Capacity: 3500 MTPDTechnology: SNAMPROGETTI Process, ITALY Carbon Dioxide requirements supplied from ammonia plant. Two urea strings have a common Prilling section.

Basic scheme involves the following steps:

Urea Synthesis Waste Water Treatment section

3.Offsite and Utilities

S. N.UNITCAPACITYTECHNOLOGY

1.Ammonia Storage Tank2X5000 MTM/S Kaveri Engineering

2.Captive Power Plant1X110 TPHTHERMAX/ L&T

3.Cooling Tower24000 M3/hrM/S Paharpur Cooling Tower

4.D. M. Water Plant3X450 M3TCL, Mithapur

5.Gas Turbine Generator2X20 MWTHOMASSON, Holland

6.Heat Recovery Unit2X90 TPHL&T

7.Naptha Bulk Storage Tank3X6300 KLM/S TechnofabEngg. Ltd.

SALIENT FEATURES OF TATA CHEMICALS LIMITED, BABRALA Location Babrala, District Sambhal, Rajpura block, Gunnor Tehsil, Uttar Pradesh. Approx. 160km. south-east of Delhi.

Land Area 1519 acres Plant area:1,069 acres Township area:350 acres Green belt: 100 acres

Fuel Natural gas (main) Naphtha (alternate)

Fuel Source Natural gas supplied by GAIL (HBJ Pipeline) Naphtha from IOCL, Mathura

Consumptive water source Eight deep bore wells.

Present installed capacity Ammonia:2000 MTPD Urea: 3500 MTPD

Man power Deployment (During Commissioning/ Erecting phase ) Total 7,855,128 man-hours. Peak (month) 405,799 man-hours.

Beneficiary states U.P., Bihar, West Bengal, Punjab, M.P., Assam.

UNIQUE FEATURES OF TATA CHEMICALS LIMITED, BABRALA

An integrated energy network, which is the key, factor in achieving high energy efficiency. The flexible range of the ratio of natural gas and naphtha as a fuel/ feed is a major reason for this. The current low operating energy record is 5.13 Gcal/MT of Urea. The second unique feature is common single central control room (CCR) for ammonia, Urea to captive power and steam generation plant (CPSSGP) and other offsite and utility plants. This provides a well-coordinated and integrated control of the entire complex from one location and on line inters plant sharing of information. This has been found extremely beneficial especially during plant startups and upsets.

2.FIRE AND SAFETY

FIRE CHEMISTRY: The well-known Fire triangle requires the three ingredients of fire namely fuel, oxygen and source of ignition.A fire is a combination of fuel, oxygen and source of ignition.2.1 FIRE PREVENTION:Fire prevention can be done in three ways:

Eliminate sources of ignition. Eliminate combustible substances. Eliminate air excess to combustible substances.

FIRE PREVENTION THROUGH ELIMINATION OF IGNITION SOURCES:To prevent fire the first is to remove the cause of fire. Studies made by fire insurance company shows that majority of fires are caused by following general sources of ignition: Electrically limited fire: Improper earthing, short circuiting, loose electrical contacts, temporary direct connections without proper fittings, high current, over heating of electrical equipment are among the common cause of electrically initiative fires. Smoking ignited fire: Smoking or even carrying cigarettes/ beedies/matches/lighter etc. in the following areas is a serious offence. All non-smoking areas should carry NO SMOKING signboards. Friction and overheated material: In flame proof areas, frictional fires can also be started by the friction of moving parts of machinery which are overheated due to excess friction. This is likely in non-lubricated and not well maintained machinery.

FIRE PREVENTION THROUGH ELIMINATION OF COMBUSTIBLE MATERIALS:

Waste and combustible materials:All combustible wastes and materials like waste paper, cotton waste etc. accumulated after a job should be transported to waste bins and is the responsibilities of the person doing the job that creates the wastes.Tins and cans of flammable materials like paints, oils, spirit etc.: These should be handled carefully ensuring that no undue spillages takes place during their uses and any spillages takes place during their use and any spillage should be cleaned immediately. Fueling of vehicle tanks: Engine should be always switched off while fueling a vehicle. If diesel or petrol spills over during fueling, dry sand should covered over the spill immediately till only dry sand is visible on the spilled area. Waste disposal:All combustible waste must be regarded in such a way that can be disposed of as such and not burnt.

PREVENTION THROUGH ELIMINATION OXYGEN SUPPLY: Smoothening: It is a process of covering the burning area with a non-combustible substance like asbestos or fire proof blanket, wet thick cotton blanket or sand.

2.2 CLASSIFICATION OF FIRES:Fires are classified according to the nature of fuel burning and fire extinguishing methods that can be applied and the following is the fire classification under the Indian fire code.

CLASS A FIRE CLASS B FIRE CLASS C FIRE CLASS D FIRE CLASS E FIRECLASS A FIRE: Fires where the burning fuel is a cellulosic material such as wood, clothing, paper etc. is called class A fire.It can be extinguished by the water and sand. Class A fires can also be extinguished by all the available means of extinguishing fires like foam, soda acid, dry chemical powder, carbon dioxide etc.CLASS B FIRE: Fires where the burning fuel is a flammable liquid Naphtha, petrol etc. are categorized as class B fire.Blanketing is a useful first aid fire control for B class fire. Water is forbidden as a fire fighting means on class B fires. Foam, carbon dioxide, dry chemical powder extinguishers are the desired means of controlling B class fires.CLASS C FIRE: Fire involving flammable like natural gases hydrogen are classified as class C fire. The best means of extinguishing C type fire is by stopping the gas supply to the leaking vessels or pipe lines if possible. This must be the intermediate and very first step. Dry chemical powder and carbon dioxide are useful in controlling C class fire.CLASS D FIRE: Fire involving material like magnesium, aluminum, zinc, potassium etc. are classified as class D fire. Sand buckets are useful in most cases of metallic fires. Special dry chemical powder also works on class D fires.CLASS E FIRE: Fires involving electrical equipments are classified as E class fires. Only carbon dioxide and D.C.P extinguishers are used on class E fires.

2.3 FIRE FIGHTING GADGETS AND APPLIANCES:- CO2:- It contain under pressurized liquid carbon dioxide. SODA ACID:- Contain a double container with sodium bicarbonate solution in outer container and dilute sulphuric acid in the inner container. After the inner container both react and produce a liquid of entrapped CO2. FOAM:- Contain aluminous sulphate in inner container and sodium bicarbonate in outer one. After cracking the container both reacts to produce carbon dioxide and the foam stabilizer makes stable form of carbon dioxide. DRY CHEMICAL POWDER:- It contains an inert dry chemical powder of sodium bicarbonate or potassium bicarbonate or potassium chloride and diammonium phosphate along with liquid carbon dioxide under pressure. HALON/ BROMOCHLOROFLUORO METHANE:-Halon is in the form of a liquid gas under pressure that is released on pressing the knob.

2.4 SAFETY PROGRAMME AT T.C.LThe company conducts regular programs for safety measures, which not only creates awareness about safety but also maintains it; the fire and safety department of T.C.L organizes many programs to motivate in this direction and to make the employees aware. National safety day 4th march is being celebrated each year with earnestness and includes various awareness programs, competitions and includes various awareness programs, competitions etc. Some of these are listed below: Training programs on safety. Home safety. Use of safety equipment. Safety quiz. Safety slogan competition.

SAFETY PROVISIONSPersonal protective equipment (PPEs): The various types of PPEs are:- Helmet for head protection. Goggles for eye protection. Ear plugs and muff for ear protection. Safety shoes for foot protection. Gloves for hand protection. Face shields foot protection. Full body protection suits. Hoods for head, neck, face, and, eye protection. Safety belts or life belts or harness. Breathing apparatus or respiratory protection equipment.Fencing of machinery.Devices for power cut.Hoists and lifts.

3.UREA SYNTHESIS (Process Description)

Urea is produced from ammonia and carbon dioxide in two equilibrium reactions:

2NH3 + CO2 NH2COONH4Ammonium carbamate

NH2COONH4 NH2CONH2 + H2Ourea

The urea manufacturing process, shown schematically in Figure below, is designed to maximisethese reactions while inhibiting biuret formation:

2NH2CONH2 NH2CONHCONH2 + NH3biuret

This reaction is undesirable, not only because it lowers the yield of urea, but because biuretburns the leaves of plants. This means that urea which contains high levels of biuret isunsuitable for use as a fertiliser. The structure of these compounds is shown in Figure 3.

Step 1 - Synthesis

A mixture of compressed CO2 and ammonia at 240 barg is reacted to form ammoniumcarbamate. This is an exothermic reaction, and heat is recovered by a boiler which producessteam. The first reactor acheives 78% conversion of the carbon dioxide to urea and the liquidis then purified. The second reactor recieves the gas from the first reactor and recyclesolutionfrom the decomposition and concentration sections. Conversion of carbon dioxide to urea isapproximately 60% at a pressure of 50 barg. The solution is then purified in the sameprocess as was used for the liquid from the first reactor.

Step 2 - PurificationThe major impurities in the mixture at this stage are water from the urea production reactionand unconsumed reactants (ammonia, carbon dioxide and ammonium carbamate). Theunconsumed reactants are removed in three stages3. Firstly, the pressure is reduced from 240to 17 barg and the solution is heated, which causes the ammonium carbamate to decomposeto ammonia and carbon dioxide:

NH2COONH4 2NH3 + CO2

At the same time, some of the ammonia and carbon dioxide flash off. The pressure is thenreduced to 2.0 barg and finally to -0.35 barg, with more ammonia and carbon dioxide beinglost at each stage. By the time the mixture is at -0.35 barg a solution of urea dissolved inwater and free of other impurities remains.At each stage the unconsumed reactants are absorbed into a water solution which is recycledto the secondary reactor. The excess ammonia is purified and used as feedstock to theprimary reactor.

Step 3 - Concentration75% of the urea solution is heated under vacuum, which evaporates off some of the water,increasing the urea concentration from 68% w/w to 80% w/w. At this stage some ureacrystals also form. The solution is then heated from 80 to 110oC to redissolve these crystalsprior to evaporation. In the evaporation stage molten urea (99% w/w) is produced at 140oC.The remaining 25% of the 68% w/w urea solution is processed under vacuum at 135oC in atwo series evaporator-separator arrangement.

Step 4 - PrillingThe urea melt is typically fed into a conical shaped bucket spinning in the centre of a concrete tall prilling tower. Sometimes static sprayers are applied. Efforts were made in the past to realize an easy, simple and reliable process. The urea melt is typically fed into a conical shaped bucket spinning in the centre of a concrete tall prilling tower. Sometimes static sprayers are applied. Efforts were made in the past to realize an easy, simple and reliable process.

Detailed Study Of Each SectionHigh Pressure Synthesis Section-Figure below shows the Process synthesis section. The reactor, stripper, carbamate condenserand ejector comprise the synthesis section as major equipment. Liquid ammonia is fed into thereactor via the ejector. Most of the CO2 is fed to the stripper as stripping media and the rest is fedto the reactor as a source of passivation air and a raw material for urea synthesis in the reactor.Carbamate solution from the carbamate condenser is fed to the reactor after being pumped by theejector that is motivated by high pressure liquid ammonia. Urea synthesis solution leaving thereactor is fed to the stripper. Stripped urea solution is sent to MP decomposition stage. Thestripped off gas is fed to vertical submerged-type carbamate condenser. NH3 and CO2 gascondenses to form ammonium carbamate and urea in the shell side of the carbamate condenser.The condensation heat is recovered to generate low pressure steam in the tube side. Packed bedis provided at the top to absorb uncondensed NH3 and CO2 into recycle carbamate solution fromMP absorption stage. Inert gas from top of the packed bed is sent to MP absorption stage. Thedriving force for liquid and gas circulation in the synthesis loop is mainly provided by the ejector,while appropriate elevation of the carbamate condenser supplies additional driving force bygravity.

The unique heat integration between the synthesis section and downstream sections furtherreduces energy requirement (See Figure). MP steam is supplied to synthesis section todecompose and separate excess NH3 and carbamate in the stripper. The stripped NH3 and CO2gas mixture is sent to the carbamate condenser and the condensation heat is recovered by the twoparallel carbamate condensers. One is utilized for decomposition in the medium pressure sectionand the other is for low pressure steam generation to be utilized in the low pressure andevaporation sections. Condensation heat in medium pressure section is also utilized inevaporation section..

Medium Pressure Decomposition Section-In this section concentration of urea takes place .It consist of medium pressure decomposition column which function is to decompose carbamate and separate from urea solution. Then there is a medium pressure condenser which function is to condense mixture of liquid and gas .Then there is a absorber which absorbs NH3 and CO2 from the reaction. There is a ammonia absorber and inert washing tower in which inert gas saturated in NH3vapour is scrubbed with cooled steam condensate. Then there is a carbonate solution pump which is used to pump carbonate to decomposition section.Low Pressure Decomposition Section-The function of this section is same as the medium pressure decomposition section but it operates at a reduced pressure then earlier.Pre VaccumAndVaccum Evaporation Section-Firstly there is vaccum pre concentrator section which is used to increase the concentration of urea solution to the evaporation section.Then partial evaporation of water present in urea solution coming from the vaccum pre concentrator holder. In second vaccumconcentrator total evaporation of water remaining in urea solution takes place. Then there is 1st and 2nd vaccum separator which is used to separate ammonia carbon dioxide and water vapours present in urea solution .Vaccum system is used to make vaccum in two evaporation section.Prilling Tower-The urea melt is typically fed into a conical shaped bucket spinning in the centre of a concrete tall prilling tower. Sometimes static sprayers are applied. Efforts were made in the past to realize an easy, simple and reliable process. The urea melt is typically fed into a conical shaped bucket spinning in the centre of a concrete tall prilling tower. Sometimes static sprayers are applied. Efforts were made in the past to realize an easy, simple and reliable process.

Prilling Tower

4.PROJECT OBJECTIVE-Comparison OfPrilling Tower On The Actual And Design Data-Brief Description Of Prilling Tower And Process Involved In It--Urea is marketed as a solution or in the solid form. Urea in solid form is produced in the final process stage by either granulation or prilling. Transformation of urea from melt to solid prills takes place in the urea prilling tower. In theprilling process, urea melt is pumped to the top of 50 to 60 meter (above ground) cylindrical concrete tower where it is fed to the prilling device that called rotating bucket. The rotating bucket is a sieve-like cylindrical or conical drum that rotates about its axis. Liquid jets emerge from the various holes on the curved surface of the drum, and break up due to centrifugal and capillary instability. The liquid urea droplets formed fall downward the prilling tower. A countercurrent cooling air stream enters from intake openings located around the circumference of the tower at a height approximately 7 meters from the ground level of the tower. Heat and mass transfer between the downward urea droplets and the upward cooling air stream along the heightof the tower occurs, and thus a solidification-cooling process takes place. The product, urea prills, goes from the tower base to a conveyor belt where it has collected and packed. The air stream exhaust from the tower through the exhausted stakes located at the top of the tower where it spreads in the surrounding environment. As ambient air is used in the process of cooling and solidification of the prills inside the tower, thus both the dry bulb temperature and humidity of the ambient air highly affect the quality of the final product Based on the reportedinformation from the company that is in some days in summer session, the prills are hot to the limit that cannot be packed directly. The delay in the packing process leads to a decrease in the yearly company production. In addition, in humid/ hot days, the lamp of prills forms at the bottom of the tower that also is not desired for the product quality.

While designing prilling tower, the following assumptions are considered:1) The droplet/ particle are spherical (from experimentalmeasurements)2) Steady state for the urea melt is maintained. 3) The pressure drop along the tower is neglected (about 0.01 Pa); therefore, constant pressure conditions can beapplied.4) Evaporation of urea in the whole process, as well as the conversion of urea to ammonia and carbon dioxide(around 0.4% as reported from the company) is neglected.5) Radiation heat transfer between urea prills and the prilling tower walls is neglected (estimated about 0.6%).6) An adiabatic process is considered due to the material (concrete low thermal conductivity =0.8-1.4 W/m. K)and large thickness of the tower wall (0.25 m)7) The volumetric ratio of droplets/ particles in the prilling tower is normally very small (around 0.1% only) so that the effects of droplets/ particles on each other in both heat transfer and movement are neglected.8) Average value of the air velocity in the axial direction is considered (0.63 m/s measured by the company).

Hydrodynamics balanceThe prilling tower has a cylindrical shape. Thus, the prilling process hydrodynamics model is derived in thecylindrical coordinates ( r,,z ) with the unit vectors ( er ,e ,k ) respectively.

Three forces affect on the particle during its fall throughthe tower. These forces are; the weight force Fw

that actsdownward,Buoyancy force FB

, and Drag force FD

The drag coefficient CD is determined by the formula for 2