A

TRAINING REPORT

ON

UREA- PLANT

TRAINING DURATION: 6 th JUNE 2011 TO 2 nd JULY 2011

SUBMITTED TO SUBMITTED BY

Dr. D. N. VERMA SAUMYA TIWARI

D. G. M.-TRAINING 3rd yr, B. Tech. (CHEMICAL ENGG.)

IFFCO PHULPUR, ALLAHABAD H.B.T.I. KANPUR

1

CERTIFICATE

This is to certify that the Training Report on UREA-1 plant has been prepared by Saumya

Tiwari d/o Rakesh Tewari ( 3rd yr B.Tech, Chemical Engineering) of HBTI Kanpur

(G.B.T.U Lucknow) and she has taken keen interest in completion of her assignment under

my guidance .

Mr. R.B. Rai Mr. A. K. Chaturvedi Mr. S.K. Mishra

D.G.M.(Urea-1) Chief manager(Urea-1) Sr. Manager(Urea-1)

IFFCO ,Phulpur, IFFCO,Phulpur, IFFCO, Phulpur,

Allahabad Allahabad Allahabad

2

ACKNOWLEDGEMENT

Industrial training is a part of our academic activities and every student has to attach

himself with any one of the leading industries for getting insight of this subject. The entire

period of training, I wish to express my gratitude to the management of IFFCO Phulpur,

Allahabad, especially its management and training department who gave me this opportunity

by permitted to me to work under their kind supervision.

I would like to express my thanks to Dr. D. N. Verma who provided me an

opportunity to do training. I wish sincerely thanks to Mr. Rajan Singh for all outwork

rendered to me for completing this training report.

At the submission of this project we take the opportunity to express our deep sense of

gratitude to Mr. R.B. Rai, Mr. A. K. Chaturvedi, Mr. S.K. Mishra and Mr. V. P. Singh for

supporting and guiding us.

We would also like to appreciate all the plant operators and engineers of this

organization who helped us enough in quenching our thirst to smallest queries.

3

TABLE OF CONTENTS:

SR. NO.

BRIEF DESCRIPTION OF CONTENTS Pg. no.

1 Introduction of IFFCO 52 Introduction of IFFCO Phulpur unit 73 Ammonia plant 103.1 Brief description of ammonia plant 113.2 Brief process description of ammonia plant 134 Urea plant 184.1 Brief description of urea plant 194.2 Urea : physical and chemical properties 204.3 Process technology 214.4 Uses of urea 224.5 Brief process description of urea plant 234.6 Effect of process variable in urea plant 294.7 Urea production performance 314.8 Equipment details 324.9 Corrosion in urea plant 364.10 Offsite description 374.11 Power distribution 424.12 DCS System 425 Environment and pollution control 436 Fire and safety 447 Conclusion 468 References 48

4

INTRODUCTION

Indian Farmers Fertilizers Co-operative Limited (IFFCO) was registered on November 3,

1967 as a Multi-unit Co-operative Society. On the enactment of the Multistate Co-operative

Societies act 1984 & 2002, the Society is deemed to be registered as a Multistate Co-

operative Society. The Society is primarily engaged in production and distribution of

fertilizers.

IFFCO commissioned an ammonia - urea complex at Kalol and the NPK/DAP plant at

Kandla both in the state of Gujarat in 1975. Another ammonia - urea complex was set up at

Phulpur in the state of Uttar Pradesh in 1981.

As part of this vision, IFFCO has acquired fertilizer unit at Paradeep in Orissa in

September 2005. As a result of these expansion projects and acquisition, IFFCO's annual

capacity has been increased to 3.69 million tons of Urea and NPK/DAP equivalent to 1.71

million tones. In pursuit of its growth and development, IFFCO had embarked upon and

successfully implemented its Corporate Plans, ‘Mission 2005’ and ‘Vision 2010’. These

plans have resulted in IFFCO becoming one of the largest producer and marketer of

Chemical fertilizers by expansion of its existing Units, setting up Joint Venture Companies

Overseas and Diversification into new Sectors.

5

IFFCO has now visualized a comprehensive plan titled ‘ Vision-2015 ’ which is presently

under implementation. IFFCO has made strategic investments in several joint ventures.

Godavari Fertilizers and Chemicals Ltd (GFCL) & Indian Potash Ltd (IPL) in India. As

part of strategic diversification, IFFCO has entered into several key sectors. IFFCO-Tokio

General Insurance Ltd (ITGI) is a foray into general insurance sector. Through ITGI,

IFFCO has formulated new services of benefit to farmers. 'Sankat Haran Bima Yojana'

provides free insurance cover to farmers along with each bag of IFFCO fertiliser purchased.

IFFCO is also behind several other companies with the sole intention of benefitting farmers.

The distribution of IFFCO's fertilizer is undertaken through over 39824 Co-operative

Societies. In addition, essential agro-inputs for IFFCO has promoted several institutions and

organizations to work for the welfare of farmers, strengthening cooperative movement,

improve Indian agriculture. Indian Farm Forestry Development Cooperative Ltd

(IFFDC), Cooperative Rural Development Trust (CORDET), IFFCO Foundation,

Kisan Sewa Trust belong to this category. An ambitious project 'ICT Initiatives for Farmers

and Cooperatives' is launched to promote e-culture in rural India. IFFCO obsessively

nurtures its relations with farmers and undertakes a large number of agricultural extension

activities for their benefit every year.

At IFFCO, the thirst for ever improving the services to farmers and member co-operatives is

greedy, commitment to quality is insurmountable and harnessing of mother earths' bounty to

drive hunger away from India in an ecologically sustainable manner is the prime mission.

IFFCO, today, is a leading player in India's fertilizer industry and is making substantial

contribution to the efforts of Indian Government to increase food grain production in the

country.

Awards & Milestones Safety Innovation Award - 2010

Greentech Gold Award for Training Excellence

ICWAI Award for Excellence in Cost Management - 2009 for IFFCO

IFFCO Shines at Public Relation Society of India, Grabbed 2 prestigious awards

IFFCO Aonla Wins "Gold Award“ - 10th Annual Greentech Environment Excellence

Award 2009

IFFCO bagged First ever dotCoop Global Award for Cooperative Excellence

IBM Awards First Prize to IFFCO for Innovation

6

IFFCO Phulpur Unit-I bagged "First Prize" by FAI.

CIO 100 & IT Awards

Microsoft Felicitates IFFCO

National Energy Conservation 2008 - 1st Award Conferred on Phulpur Unit

IFFCO bags three FAI Awards

IFFCO bags Energy conservation award

Phulpur Unit bags National Energy Award from Honorable President of India

Best Managed Work Force Award for IFFCO

IFFCO PHULPUR UNIT

Head of the Unit : Mr. Surjit Singh (Sr. Executive Director)

Total Area 1068 acres

Area Under plant 321 acres

Area under Township Area under township, cordet, agricultural farms, green belt, ash ponds, roads, Open space: 747 acres.

IFFCO Phulpur is a large scale modern fertilizer complex having two ammonia plants and

two urea plants. A turbo generator set has been provided to insulate the plant operations from

the effects of unreliable imported electric power. Coal handling, ash handling, inert gas

generation plant naphtha fuel oil and diesel storage and handling facilities. 10000 tons

capacity of atm ammonia storage and loading facility bagging and material handling etc are

often auxiliary units of ammonia and urea complex. Consultants for ammonia, urea and

offsite facilities were respectively Pullman Kellog, Snam Progetti and Development

consultants.

LOCATION:

Unit is located in the heartland of gangetic zone which is India’s prime agriculture belt at

Phulpur district Allahabad in the state of U.P. The site is located in U.P. highway no. 7

connecting Allahabad to Jaunpur and Gorakhpur Phulpur, which is a tehsil, is about 5 km.

7

away from the site and linked with broad gauge line on the Varanasi- Allahabad railway

route.

Phulpur I Process Licensor Date of Commercial production

Ammonia Plant MW Kellog, U.S.A Urea Plant Snamprogetti, Italy 28th MAR 1981

Phulpur II Process Licensor Date of Commercial production

Ammonia Plant HTAS, Denmark Urea Plant Snamprogetti, Italy DEC 22nd , 1997

PHULPUR PRODUCTION CAPACITY:

PLANT PRODUCTION IN MTPD

PHULPUR-1

AMMONIA : 1215

UREA : 2115

PHULPUR-2

AMMONIA

UREA

:

:

1740

3030

8

Phulpur Unit - Records & Achievements

Highlights of 2009-2010 of Phulpur Unit has Achieved Highest ever Yearly Production with Lowest ever Yearly Energy in All Plants. Longest Accident free period of 1721 days till March 31,’10 is continuing since 15th July, 2005. Golden Jubilee Award in Recognition & Appreciation of Extraordinary Accomplishment and Contribution to the Nation from Chamber of Commerce & Industry, (Eastern U.P., Allahabad)

Phulpur Unit: Records & Achievements

Unit-I 1. Fifteen million tonne of Urea Production have been achieved in a period of 568 days on 20.07.2009. 2. Eight million tons of Ammonia production has been achieved in a period of 1064 days on 02.10.2007.3. Fifteen million tons of Urea Dispatch (By road & rail) achieved in a period of 568 days on 20.07.2009.

Unit-II

1. Ten million tons of Urea Production has been achieved in a period of 392 days on 07.08.2009. 2. Six million tons of Ammonia production has been achieved in a period of 717 days on 01.12.09.3. Ten million tons of Urea Dispatch (By road & rail) achieved in a period of 387 days on 06.08.09.

9

AMMONIA- PLANT

10

Brief Description of Ammonia Plant

The Ammonia plant in Phulpur-I is based on MW Kellogs USA

technology having capacity of 1215 MTPD and in Phulpur-II plant is

based on Haldor Topsoe’s Denmark’s technology with a capacity of 1740

MTPD.

The Ammonia Plant in Phulpur-I and Phulpur-II uses RLNG as raw

material for feed and fuel. But there is a provision of using Naphtha also as

raw material in Phulpur-II.

The main process steps for production of Ammonia in both the plants are

similar and are briefly described below:

Raw material:RLNG is used as main raw material to produce ammonia which has the following

composition:

CH4 : 98.77%

C2H6 : 0.69%

N2 : 0.51%

C3H8 : 0.03%

11

BLOCK DIAGRAM FOR AMMONIA PROCESSING

12

BRIEF PROCESS DESCRIPTION OF AMMONIA PRODUCTION:

DesulphurisationThe Traces of sulphur present in RLNG are removed in the desulphurisation section

before sending to the reforming section following hydrogenation reactions are as under:

1) RSH + H2 = RH + H2S

2) COS + H2 = CO + H2S

3) C4H4S + 4H2 = C4H10 + H2S

The desulphuriser reactor consists of Co, Mo based catalyst and ZnO based catalyst.

The desulphurisation takes place in two steps. The first step is hydrogenation where

organic sulphur is converted into Hydrogen sulphide over the hydrogenation catalyst in

the HDS reactor. The second step is the absorption of the H2S formed which takes

place in 2 nos. ZnO absorbers connected in series.

Reforming Section

In the reforming section consisting of Pre-reformer, Primary reformer & Secondary

reformer, the sulphur free RLNG is reformed with steam and air into raw synthesis gas

(process gas) at a pressure of 30 - 37 kg / cm2. The gas contains mainly hydrogen,

nitrogen, carbon monoxide (CO) and carbon dioxide (CO2).

The steam reforming process can be described by the following reaction:

(i) Cn H2n+2H2O = Cn-1H2nCO2+3H2 - heat

(ii) CH4 +2H2O = CO2 + 4H2 - heat

(iii) CO2 + H2 = CO + H2O - heat

Since the reaction is highly endothermic, RLNG is fired in furnace as fuel to maintain

the temperature at about 800 deg C. The reformed process gas has a temperature of

about 800 deg. C and contains about 9-11 mole% (dry basis) of methane and around 70

% hydrogen.

13

SECONDARY REFORMINGSecondary reforming, which including mixing and combustion of the reformed process

gas with process air, takes place in the secondary reformer. Secondary reformer consists

of Ni based catalyst. The process gas (31.5 kg/cm2g, 800 deg C) enters the Secondary

reformer at the top. The reaction between oxygen and process gas is a combustion

where all the oxygen is utilized, raising the temperature to about 1200 deg C. When

passing the catalyst bed, the temperature decreases to about 975 deg C and the pressure

to 31 kg/cm2 g. The Outlet gas from Secondary Reformer contains about 56 %

hydrogen.

2H2 + Air (O2 + 3.8 N2 ) 2H2O + 3.8 N2 + Heat

CH4 + 5 Air (O2 + 3.8 N2) CO2+2CO + 6H2O + 19 N2 +Heat

Gas Purification SystemThe gas purification section comprises three main process steps:

1) CO conversion

2) CO2 Removal

3) Process Condensate Stripping

4) Methanation

CO-Conversion SectionThe reformed process gas enters into CO-conversion section comprising the two

CO-converters and equipment for process gas cooling and condensate separation.

The main part of the carbon monoxide is converted into carbon dioxide by the shift

reaction:

CO + H2O = CO2 + H2 + Heat

The heat evolved is primarily used for steam production and boiler feed water

preheating.

14

High Temperature CO-Conversion

The high temperature CO-converter comprises two catalyst beds. The process gas

enters the top of the converter and passes the two beds the normal outlet

temperature of the gas is about 424 deg. The outlet gas from HT Shift Converter

contains around 3% CO.

Low Temperature CO conversion

The gas leaving the high temperature CO-converter is cooled in HP waste heat

boiler, in the trim heater and in the boiler feed water preheater. Process gas entering

the low temperature CO converter has a content of 2.98 mole% carbon monoxide.

The gas leaves the converter at about 219 deg C and 29.1 kg/cm2 g.The process gas

is cooled in the boiler feed water preheater. Before entering the CO2 removal

section. The process condensate is separated in the separator inlet reboiler.The

outlet gas from LTshift converter contains around 0.12 % CO

Carbon dioxide Removal Section

Basically, the CO2 removal section comprises of Absorber, where the CO2 content

in the process gas will be absorbed in liquid phase at high pressure. The liquid

containing the CO2 is transferred to tower regeneration unit. Consisting of two

Strippers operating at different pressure. In these two towers the pressure is low and

thereby, due to equilibrium, the CO2 again will be transferred into the gas phase.

Carbondioxide is removed by absorption in hot potassium carbonate solution containing

approx. 27 wt% potassium carbonate. The solution also contains glycine and diethanol

amine as activators and vanadium pentaoxide as corrosion inhibitor. The gas passes the

separator OH absorber and enters the methanation section. The solution enters the top of

1st regenerator column. The solution passes down through the packed beds in the column

in counter current with steam. The steam strips off the carbon dioxide, and a mixture of

15

steam and carbon dioxide leaves the top of the column the CO2 thus evolved is sent to

urea plant and regenerated solution is recirculated back to CO2 absorber.

K2 CO3 + H2O + CO2 2 KHCO3 (ABSORPTION)

2KHCO3 K2CO3 + CO2 + H2O (STRIPPING)

Methanation Section

Following reactions take place in methanator.

(i) CO + 3H2 = CH4 + H2O + Heat

(ii) CO2 + 4H2 = CH4 + 2H2O + Heat

The process gas from carbon dioxide removal section still contains about 0.05 vol%

CO2 and 0.30 vol % CO As the carbon dioxides are poisonous to the ammonia

synthesis catalyst, it is converted in the methanator by use of hydrogen.

The outlet gas from Methanator contains around 73 % H2, 25 % N2, and 0.7 % CH4.

Ammonia Synthesis Section

COMPOSITION OF SYN GASES:

H2 : 73.78%

N2 : 25.39%

Ar : 0.31%

CH4 : 0.59%

The gases after the methanator outlet are sent to synthesis loop for conversion of

N2& H2 into NH3. The gases are introduced in synthesis gas compressor where the

pressure is increased to around 180 Kg/cm2. since ammonia reaction take place at

elevated pressure.

16

Ammonia ConversionThe ammonia conversion is carried out in two converters installed in series. One

original converter and another (S-50) installed during Energy Saving Project (ESP).

Ammonia converter catalyst is promoted Iron.

Reaction: 3H2 + N2 = 2NH3 + Heat

Since the reaction is highly exothermic the waste heat is utilised for generating steam

and Boiler feed water heating. TThe gases are cooled in a series of Chillers and the

ammonia get condensed a series of chillers and the ammonia get condensed and is

separated. The uncondensed gases are recycled back to Synthesis Gas Compressor.

The liquid NH3 separated out in a high pressure separator is taken to a lower

pressure separator where the inerts are separated out. This liquid NH3 is taken to

Another flash drum for removal of inerts and liquid NH3 is sent to Urea plant or

Ammonia Storage Tanks.

17

UREA-1 PLANT

18

Brief Description of Urea Plant

The Urea Plant is based on Snamprogetti’s Ammonia stripping process. The

Phulpur-I plant is having capacity of 2115 MTPD while in Phulpur-II there are

two units with a capacity each of 1515 MTPD.

The process of manufacturing of urea in both the units is same except for Phulpur-II

where all the sections are separate for two streams except for Prilling and waste

water treatment section which are common for both the units.

RECORDS: PRODUCTION IN UREA-1 PLANT

HIGHEST PRODUCTION:

DAILY : 2401.00 MT (14/06/2010)

MONTHLY : 70105.80 MT (OCT 2009)

YEARLY : 745131 MT (2010-2011)

LOWEST ENERGY CONSUMPTION:

MONTHLY : 6.4677 GCAL/MT (2010-11)

YEARLY : 6.6698 GCAL/MT (MARCH’2011)

LOWEST SP. STEAM CONSUMPTION:

MONTH : 1.0700 MT/MT (DEC’2010)

YEAR : 1.0908 MT/MT (2010-11)

19

UREA

PHYSICAL AND CHEMICAL PROPERTIES OF UREA

Molecular weight : 60.05

Melting point : 132.600 C

Boiling point : Decomposes at atm. press. Before

boiling.

Specific Gravity : 1.355

(Crystal) at 200 C

Heat of combustion : 2531 Cal/g

Heat of solution in water : -57.8 Cal/g

Critical Humidity : 70.1%

Viscosity at 1500 C : 2.16 CPS

Crystallization heat : 47 Kcal / kg.

Fusion Heat : 59.95 Kcal/kg.

Thermal conductivity : 0.191 K.cal/cm0 C

Specific heat at 200 C 98.40 C 120.50 C 160.30 C 2200 C

(Cal/gm0C) 0.321 0.158 0.194 0.224 0.288

20

Solubility in at 00C 200C 400C 600C 800C 1000C

Water (wt%) 67 105 163 240 396 725

Urea is a white crystalline chemical product and is readily soluble in water. On heating

beyond it’s m.p. It decomposes leaving CO2, NH3 and other complex compounds of C, N2O.

At 1600 C, it decomposes to yield NH3, biuret and higher condensation product and longer

the Urea is held above it’s m.p. further the reaction process.

PROCESS TECHNOLOGY :

Urea is produced by synthesis from liquid NH3 and gaseous CO2. NH3 & CO2 react to form

ammonium carbamate, a portion of which is dehydrated to form Urea and water.

The fraction of ammonium carbamate that dehydrates is determined by the ratio of the

various reactants, the operating temperature and the residence lime in the reactor.

The reaction to produce Urea from NH3 and CO2 takes place in two stages at elevated

pressure & temperature.

2NH3 + CO2 = NH2COO NH4 + 38.1 K.cal/g.mole (1)

NH2 COONH4 = NH2CONH2 + H2O -7.1 K.cal/g.mole (2)

The first reaction is strongly exothermic, therefore heat is liberated as this reaction occurs.

With excess NH3, the CO2 conversion to carbamate is almost 100%, provided solution

pressure is greater than decomposition pressure of carbamate. The decomposition pressure

is the pressure at which carbamate will decompose back into CO2 and NH3. Decomposition

pressure is a function of NH3 concentration in the feed and solution temperature and

increases if either temp. of NH3 recycle is increased. It is desirable to operate at high

temperature and high ratio of NH3 to CO2 provided reactor pressure is high enough to

prevent carbamate from decomposing into CO2 and NH3. This will maximize CO2

conversion to Urea as shown in the reaction (2)

21

The 2nd reaction is endothermic, therefore heat is required for this reaction to occur. The

heat for this reaction comes from the formation of carbamate. This reaction is a function of

temp. and NH3 concern in feed. The solution effluent from the reactor being a mixture of

Urea solution, ammonium carbamate, unreacted NH3, water and CO2 is extremely corrosive

in nature.

USES OF UREA:

1. As Fertilizer in agriculture; Due to high N-content of Urea demand of Fertilizer grade

Urea is rising rapidly. Urea today accounts for a large percentage of Nitrogenous

Fertilizer.

2. As cattle Feed: Urea is used as cattle feed in western countries – sheep and cattle are

capable of digesting Urea upto about 40% of their protein requirement.

3. As raw material for various industrial products: Urea also is used extensively in

preparation of adhesives, textile, anti-shrink compound, ion-exchange and as an

intermediate in the preparation of pigments.

22

23

BRIEF PROCESS DESCRIPTION OF UREA PLANT

Urea is commercially manufactured by direct synthesis of gaseous CO2 and liquid NH3. Urea

production process consists of the following main operations:

Process Technology

The Urea production process takes place through the following main operations:

a) Urea synthesis and high pressure recovery.

b) Urea purification and low pressure recovery.

c) Urea concentration.

d) Urea prilling

e) Waste Water treatment

a) Urea synthesis and high pressure recovery

CO2 gas mixed with a small measured quantity of air is compressed in a turbine

driven four stage centrifugal compressor to about 160 Ata and fed to the reactor.

The liquid ammonia is pumped at high pressure pumps to a pressure of about 240

Ata through an ejector which drives the carbamate from carbamate separator

into the reactor In the Urea reactor operating at 150 kg/cm2 and 190 deg.c.

Ammonia along with recycle Carbamate, reacts with compressed CO2 to form

Ammonia carbamate, a part of which dehydrates to Urea and water. The oxygen

in the air forms a passive oxide layer on the surface of the vessel to prevent

corrosion by carbamate and urea.

The reaction products from the reactor overflow to HP stripper where most of the

un reacted carbamate get stripped off as gaseous Ammonia and CO2. Heat of

decomposition is supplied by MP steam, admitted into Stripper shell side. Urea

solution thus obtained flows out to the MP section. The vapours produced on

decomposition of carbamate in HP stripper enter the HP carbamate condenser,

along with weak carbamate solution from MP section through a mixer. Gases

condensed to form carbamate again and flow to the HP  carbamate separator.

24

During this condensation, LP steam is generated in the HP carbamate condenser

shell side. Condensate required for generating steam is supplied from shell side

of MP decomposer.

b) Urea purification and low pressure recovery

Medium Pressure Section

Urea solution from the bottom of the HP Stripper now enters the bottom of Pre-

Decomposer and then to MP Decomposer for further decomposition. During

expansion much of the remaining Carbamate flashes forming NH3 and CO2

vapours, thereby concentrating urea in the solution. This urea solution is further

let down through a level control valve and enters the LP section.

The vapours from the MP Decomposer are condensed in MP condenser using

ammonium carbonate solution from the LP section, with tempered cooling water

in the tube side. The carbamate solution overflows from the MP Condenser into

MP Absorber where the excess Ammonia and inerts are separated in form the

vapours. These vapours are further purified in the top section of the Absorber

with reflux ammonia. Ammonia with inert gases leaving the top of MP Absorber

is mostly condensed in Ammonia Condenser, with cooling water in tube side.

From Ammonia Condenser both liquid and gas phases are sent to Ammonia

receiver along with incoming liquid Ammonia. The inert gases, saturated with

Ammonia, leaving the receiver enter the Ammonia Recovery Tower, Here

Ammonia is further condensed by direct contact with cold Ammonia from the

Battery limit and flows down the Ammonia Receiver.

The inerts with residual ammonia vapours from the Tower are sent to MP

Ammonia Absorber where later gets absorbed with cold condensate in inert

washing tower and recycled to MP Absorber as ammonia water. The inerts are

released to vent stack.

25

26

Low Pressure Section :

The Urea solution from MP Decomposer bottom enters the LP Decomposer after

let down through a level control valve. As a result of expansion, most of the

remaining carbamate undergoes decomposition. Thus Urea solution is further

concentrated and is then sent to the vacuum concentrators through a level control

valve. The vapours enter the LP condenser shell and get absorbed in a weak

Carbamate solution. LP condenser has cooling water in tube side. The liquid thus

formed goes to the Carbonate Solution Tank from where it is recycled back to

MP Condenser.

The inert gases from the Tank containing ammonia vapours are absorbed with

cold condensate in LP Ammonia Absorber and sent to vent stack. The liquid

flows down to the Tank. The concentration of urea is approx. 70% at the outlet.

Urea concentration section

The liquid from the bottom of LP decomposer is further concentrated in

Preconcentrator and then goes for further in two Vacuum concentrators in series.

Here with the help of Low pressure steam, urea solution is concentrated from

70% to 99.7%. The vacuum is created and maintained by two vacuum systems

consisting of a set of steam ejectors and condensers.

Urea melt thus obtained is then pumped to the prilling tower. The vapours from

the vacuum separators are condensed in the condensers and sent to the waste

water tank.

d) Urea prilling

The melted Urea leaving the second vacuum separator is pumped to the top of

104 meter high natural draft prilling tower and sprayed by means of rotating prill

bucket. The fine droplets, while descending through the tower come into contract

with cold air and solidify to from prills. These prills are conveyed to bagging

plant for bagging or to Urea silo for storage.

27

e) Waste water treatment

Traces of gases present in the condensate from vacuum section are removed in a

Hydrolyser stripper system. Waste water from the Hydrolyser section is sent to

the effluent system. The recovered Ammonia solution is recycled back to the LP

recovery section and Ammonium carbamate from LP section is recycled back to

the MP recovery section.

FCO LIMIT PHULPUR UREA

Total N% (min on dry basis) 46 46.6

Moisture % ( max.) 1.0 0.45

Biuret % (max.) 1.5 1.0

FIG: Schematic view of urea

28

EFFECT OF PROCESS VARIABLE IN UREA PRODUCTION

The equilibrium conversion to Urea will be favored under the following process variables :

I) Higher ammonia concentration.

II) Less H2O concentration.

III) Higher temperature.

IV) Higher pressure.

V) Increased residence time.

I) EFFECT OF NH3 / CO2 RATIO:

Theoretical ratio of NH3 / CO2 is two. But in this condition Urea yield is only around

43.44% at 170 atm. and 1550 C. This low yield can be improved by changing NH3 / CO2

ratio when the excess ratio of NH3 is increased to 279%, Urea yield will change from

43.44% to 85.2%. On the other hand when the excess ratio of CO 2 is changed from 0-300%,

Urea yield will increase only from 43.44% to 46%. The effect of excess CO2 is very small.

More over, in the CO2 rich condition the soln becomes very corrosive. In general, most all

the Urea plants are operated under NH3/CO2 ratio around 2.5 to 5.0.

II) EFFECT OF H 2O/CO2 RATIO: Water is a product of Urea formation, presence of excess H2O shifts the equilibrium reaction

in reverse direction and yield of urea is poor. However water has to be added for recycling

unconverted NH3 and CO2 back to the reactor. Lower the amount of water in reactor higher

is the yield of Urea. Excess H2O in reactor also reduces effective volume for urea formation

and additional energy is required to get rid of this H2O. Study shows that presence of one

mole of excess H2O per mole of carbamate reduces equilibrium yield of urea to half.

III) EFFECT OF PRESSURE AND TEMPERATURE :As per Le-chaterlier’s principal higher pressure favoured carbamate formation. At the

operating condition carbamate formation is almost instantaneous and reaction tends to

29

completion provided reaction heat is removed simultaneously. Lower temperature favoured

carbamate formation, being an exothermic reaction.

In case of Urea formation, higher temperature is favourable, because the reaction is

endothermic. The relation is such that when temperature increases, the conversion increases

proportion only, maximum equilibrium conversion is achieved at around 196-2000 C.

Reactants are highly corrosive at higher temperature.

Operating pressure is totally dependent on the temperature at which conversion takes place.

Urea conversion takes place in liquid phase, so equilibrium pressure becomes increasingly

higher when the temperature rises.

IV) RESIDENCE TIME :Urea conversion reaction is slow and takes 20 mins. To attain equilibrium. Higher residence

time favoured equilibrium. Conversion and normally reactors are designed for residence time

of 30 mins to one hour depending upon there operating parameters.

Residence time in Urea reactor plays an important part on equilibrium conversion. Where

operating parameters including mole ratio are not favourable for a good yield, higher

residence – time compensates to some extent to achieve a better yield. But this is done by

providing higher reactor volume which increases capital investment.

BIURET IN UREA:

The formation of biuret during Urea production is not desirable as it is toxic to the plants and

it should not exceeds more than 1.5% in Urea as per Fertilizer control order. It is produced

when Urea is heated in the absence of free NH3.

NH2CONH2 + NH2CONH2 → NH2 CO NH CO NH2 + NH3

(Urea) (Biuret )

The formation of biuret is favoured by higher temperature, higher concentration of urea

solution, low NH3 content and higher residence time.

30

31

EQUIPMENTS DETAILS:

REACTOR

SUPPLIER: MITSUBISHI HEAVY INDUSTRIES LTD., JAPAN

The liquid mixture of NH3 & carbamate and gaseous CO2 are fed in reactor where these react to form ammonium carbamae, a portion of which dehydrates to form Urea & Water. The reactor is vertically mounted and made of carbon steel. It is internally lined with 5 mm thick stainless steel liner 316-L (Modified). The reactor has 14 nos. sieve trays numbered from top over a length of 35 meter. Serve trays are provided to avoid back mixing & for improvement of contact between gaseous & liquid phase. The liquid & gases flow from bottom top via these sieve plates. Reaction products after leaving the reactor are sent to stripper.

OPERATING DETAILS:Units

Operating Pressure Kg/cm2a 151Operating Temperature 0C 185Design Pressure Kg/cm2a 166Design Temperature 0C 195

MECHANICAL DETAILS:

Length mm 36,000 (Tan to tan)I.D. mm 2,305O.D. mm 2494Internal lining mm 5 mm thick 316-L (Modified)Total nos. of sieve trays Nos. 14

MATERIAL OF CONSTURCTION

Shell : Carbon steel Sieve trays : SS 316-L (Modified)All internal walls & linerIn contact with fluid : SS 316-L (Modified)

Composition of 316 – L (Modified)

Cr -- 22% Ni > 12%

Mo > 2.2% N < 0.2%

C < .03%

32

MP DECOMPOSER

SUPPLIED BY : LARSEN AND TOUBRO LTD. BOMBAY

Solution from the stripper is flashed in MP separator (MV-2) at 18 Ata pressure. Due to flashing some Ammonia and CO2 is released from the solution. The rest of the solution is heated in MP decomposer E-2 to decompose carbamate into Ammonia CO2 and water at 18 Ata pressure. MP decomposer is a falling film type heat exchanger.

The solution containing Urea, Water, Unconverted cabamate and Ammonia is fed over the tube sheet. The solution enters the decomposer tubes through a set of four holes.The tube sheet at the top and bottom both have a 10 mm thick overlay of SS-3316-L. Shell side fluid is 26 ata steam condensate (from stripper shell side) as heating medium. Expansion belows are provided for the shell.

OPERATING DETAILS: Units Shell Tube

Fluid Handled - Steam Urea +Condensate Carb+

Water +ammonia

Design Pressure Kg/cm2 28 22

Design Temperature 0C 225 185

Operating Pressure Kg/cm2 25 17

Operating Temperature

In 0C 225 129

Out 0C 161 155

Heat Duty MK Cals/hr – 4.2

33

MECHANICAL DETAILS: Units

Material of construction - SS 316L and 10mm thick overlay of SS 316L on tubesheets.

No. of Tubes Nos. 543

Tube O.D. mm 38

Tube I.D. mm 34.8

Heat Transfer Area M2 390

Effective length mm 6,000

LP DECOMPOSER SUPPLIER BY: Larsen and Toubro Ltd., Bombay

LP decomposer is a falling film heat exchanger which decomposes carbamate present in Urea solution. Solution is distributed into the decomposer tubes through the ferrules fitted on them. Each ferrule is provided with 4 holes through which liquid flows down to tubes. The 4 holes are essentially on the same plane and are tangential to the surface of the ferrule. The tangential entry ensures that liquid is in the form of a film flowing along the wall of the tubes. Vapors of water, ammonia and CO2 leave the decomposer tubes top. The heating medium is 4.5 Ata steam. The shell side has an expansion joint for differential expansion.

OPERATING DETAILS: UNITS SHELL TUBE

Fluid Handled --- Steam Urea +

Water some carbamate

Designed:Pressure Kg/cm2g 5.5 5.5Temperature 0C 180 170

Operating:

Pressure Kg/cm2g 3.5 3.5

Temperature:

34

In 0C 147 95

Out 0C 147 138

No. of passes No 1 1Heat Duty MKCal/hr. 3.1

MECHANICAL DETAILS FOR TUBES Units

Material of construction --- SS 316-LNo. of rubes Nos. 785O.D. mm 38.0I.D. mm 34.8Effective length m 6

MECHANICAL DETAILS FOR SHEEL:

Material of construction - Carbon steel I.D. MM 1,500Steam inlet Nozzle dia Inches 8Condensate outlet nozzle dia Inches 3

PRILLING TOWER:

ERECTOR: M/s E.C.C., BOMBAY

This is a concrete structure of 96 meter height. The urea melt enters the rotating prill

bucket situated just below the prill tower ceiling. Melt enters at a temperature of

about 1400C and is distributed in fine droplets over the cross section of the tower of

22 meter diameter and having free falling height of 72.5 meters.

It is a natural draft tower where ambient air enters through bottom lower openings

having total area 57 M2.During the fall through bucket, the droplets of urea first

solidify and then cooled to a temperature of about 600C-650C. Hot air outlet windows

are provided at the top having total area 153 M2.

The prill are scraped by a rotating straight double arm scraper and fed to the prill

tower conveyor through openings in the rake floor. The inside wall of the tower is

painted with epoxy painting & bottom floor where prills fall are coated with FRP

coating to resist corrosion. 1,000 mm x 1,000 mm inspection windows with light are

provided every four flights of external stairway. One elevator runs parallel to the prill

tower structure. Over & above the elevator, external staircase is also provided. 35

CORROSION IN UREA PLANT EQUIPMENTS:

Studies of corrosion in urea plant have led to the identification of the following type of

corrosion:

1) Stress corrosion.

2) Inter granular corrosion.

3) Galvanic corrosion.

4) Crevice corrosion.

5) Pitting corrosion.

6) Condensation corrosion.

Most severe corrosion in urea plant occurs at location where urea and carbamate solution are

handled at high temperature and pressure. Studies have shown that major attack occurs at the

bottom. 3 to 10 of the reactor directly; above where NH3, CO2 and ammonium carbamate are

introduced. In view of higher pressure, temperature, cone and two phases mixture in urea

reactor a liner of stainless steel 31 GL is used in the construction. Ti, Zr, and stainless steel

are used as liner material. As to selection of material, corrosion resistance is not the only

factor that determines the choice of material, other factor such as mechanical properties,

workability weld ability and economic consideration are taken into consideration.

36

OFFSITES:

SECTIONS:

1. Borewells and Raw Water Distribution System.

2. Cooling Tower.

3. DM and CPU Units.

4. Effluent Treatment Plant

5. Water Softening plant

6. AMF Plant

7. RO Plant

8. IG Plant

EFFLUENT TREATMENT PLANT

INTRODUCTION:

Removal & control of nitrogenous compounds such as NH3 that is present in waste being

discharged from ammonia plant and urea plant is very essential in view of pollution control

and water reuse philosophy. As water is one of the precious natural resources for running any

industry its reuse and conservation is essential for environmental pollution control and to

reduce operating cost of the industry.

To overcome problems associated with disposal of ammonia effluent and making it fit for

reuse the effluent treatment plant is installed in which NH3 present in effluent water is

reduced by stripping process.

BRIEF PROCESS DESCRIPTION

To carry out the stripping process a packed column called steam stripper is provided in which

the raw effluent is fed from the top and the LP steam is introduced from the bottom. The

stripping occurs and the treated water obtained is transferred to softening plant.

37

WATER SOFTENING PLANT

Water source of raw water required for the plant is underground sub-soil water containing

salts of sodium, magnesium and calcium, together with bicarbonate, carbonate, sulphates,

chlorides and silica (Major constituents) and Nitrate, Phosphate, Iron, Organic matter and

dissolved gases (Minor constituents). On using the raw water having high hardness as

cooling water make up, these salts break during heat transfer process inside the heat

exchangers and thereby form scales.

To bring down the concentration of calcium and magnesium hardness and also silica in

cooling tower make up water, “cold lime softening process” is adopted. The raw containing

high HCO3 alkalinity is reduced during treatment with lime solution and the treated water

becomes suitable for cooling water make up.

The capacity of the water softening plant under Phase-II is to treat 800 m3/hr. of raw water

and the other design basis is:

Design treated water quality and softening plant Phase-II outlet is following:

pH - 10.4 to 10.7

Total hardness < 50 ppm as CaCO3

Ca hardness < 40 ppm as CaCO3

Turbidity < 12 NTU

REVERSE OSMOSIS PLANT

Normally when 2 solutions are separated by means of semi – permeable membrane, the

solvent flows from dilute solution to concentrated solution. If pressure is applied to

concentrated side and if the pressure is greater than osmotic pressure, then solvent flow is

reversed, i.e., it flow from concentrated solution side. This process is called reverse osmosis.

It is advantageously used to extract water from concentrated solution.

During R.O. process, pressure is continuously applied to the feed stream by a high pressure

pump. Consequently feed stream gets divided into two parts.

38

1. Permeate stream (low in dissolved solid content)

2. Reject stream (very high in dissolved solid content)

PROCESS DESCRIPTION:

The water is fed to the R.O. plant from R.O. feed pit. In the feed some chlorine is introduced

in concentration of 1 ppm. This chlorine kills bacteria and algae, which is harmful to

membrane.

From feed pit the water is entered into solid catalyst classifier. In this classifier dolomite and

lime is introduced in solid form (not in fully powdered form). Here 0.1% of a polymer

solution is also added. This polymer coagulates the silica, which is deposited on dolomite and

lime, into large size. Hence the effluent from classifier is reduced in silica and turbidity from

that of water in feed.

To the classifier effluent 10% sodium – hexa-meta phosphate (SHMP) is added. The solution

acts as an anti scalar. The effluent then enters into 4 continuous filters. These filters are

actually sand filters having sands of uniform size. The effluent from these fitters is

maintained at pH 6.5 by addition of 30% HCl and stored in clarified water storage tank. The

rejects from solid contact classifier and 4 continuous filters are sent to sludge – pit where it is

poured and dried. The dried solid material was then sent into ash pond. This classified water

is used as power water and in chemical tanks (dolomite, lime etc). Introducing it in

multigrade filters, in which different sizes of sand layers are used as filter, further purifies

this water. The effluent from multigrade filters then passes through a basket type cartridge

filter. The cartridge filter removes suspended particles from water. When the differential

pressure across the cartridge filter reaches 1 kg/cm2 when the flow rate through cartridge

filter reduces, the cartridge filter must be replaced. The effluent from this filter then enters

into 2 micron cartridge filters, removes suspended particles upto 5 micron. The effluent from

micron cartridge filter then enters into R.O. skid. The R.O. unit consists of single stream 3

stages. There are total 37 pressure tubes each containing 6 No. of membrane modules:-

The 1st stage contains 20 pressure tubes.

The 2nd stage contains 11 pressure tubes.

The 3rd stage contains 6 pressure tubes.

39

The membrane elements mainly made of polyamide films, imported from USA. The total

input flow rate to this R.O. unit is 150 m3/hr. the flow rate through each pressure tube is 7

m2 / hr. (approx.)

Hence total product water is (75+35+15) = 125 m3/hr. and reject is 150 m3/hr. The maximum

load can be handled by this R.O. unit is 165 m3/hr.

The product water is stored in product water tank and from there supplied to different plants,

such as DM plant and softening plant inlet.

D.M. PLANT

In the D.M. Plant the deep bore raw water containing various impurities is demineralized i.e.

freed from the various minerals present in it to make it 100% free from particulate matter for

its further usage as the boiler feed water and process water.

The recommended quality of D.M. water being used in high pressure boiler is:

Conductivity (mho/cm) : Less than 0.3 micron

Silica : Less than 0.01 ppm

SiO2 hardness : Nil

Electrical char. due to electrolyte : Nil

pH : 6.8-7.5

Raw water is passed to first sand filter to remove suspended impurities then to SAC (strong

acid cation).

In SAC cation resin is used to remove cationic part of impurities like NaCl, CaHCO3

etc.

Re-H + NaCl → Re-Na + HCl

Re-H + CaHCO3 → Re-Ca + H2CO3

From SAC the process stream is passed to degasser where CO2 is removed from

water by stripping it using air.

H2CO3 → H2O + CO2

Then the stream is passed to weak base anion exchanger (WBA). Here the weak base

resin removes basic ion impurities.40

Re-OH + HCl → Re-Cl + H2O

Then the stream is passed through SBA (strong base anion). Where strong base resin

is used to remove remaining anion impurities.

From this the stream is passed through mixed bed. It contains both anionic and

cationic resins to remove both cation and anion impurities.

Finally this demineralized water stream is passed to D.M. water tank.

Power Distribution in Urea Plants:

T.G.1 - 12.5 MW41

T.G.2 - 18 MW

Total power required 25.17 M

Urea1 - 3.75 MW

Urea 2 - 6.5 MW

DISTRIBUTED CONTROL SYSTEM (DCS)

BRIEF DESCRIPTION OF DCS:

Computer based ‘Distributed Control Systems’ have been used in large quantities instead of

pneumatic control or electronic analogue control system.

In D.C.S. system, three types of distribution exists:

a) Geographical Distribution.

b) Functional Distribution

c) Safety Distribution

DCS is more accurate, fast in operation, more users friendly more informatics and equipped

to take care of start up and shutdown of plants.

In Urea plant of IFFCO Phulpur expansion, DCS model is CENTUM-CS, supplied by M/s

Yokogawa Blue Star Ltd. India. DCS collects the database from various section of the plant

directly for open loop tags for monitoring, recording and control of process parameters.

There are six information and command station comprising of six CRT screens and one

engineering station for maintenance and configuration purpose.

One PC is provided for loop drawing.

One PC is provided with HART maintenance system for maintaining field

instrument working with HART protocol. A transient data Manager (TDM) is

also a part of DCS used for monitoring temperature and vibration of bearing of

turbines, compressor and high pressure carbamate pumps. One PC is also

provided along with TDM for storing, monitoring and analysis of the temperature

and vibration.

Main Function of DCS Are:

42

1. Control and monitoring of various process parameters.

2. Data acquisition and storage.

3. Data management, manipulations and report generation etc.

ENVIRONMENT AND POLLUTION CONTROL

At IFFCO Phulpur Unit there has been an emphasis on keeping the environment clean and

safe. Due to a continuous and dedicated efforts in this direction goal of zero discharge of

effluent has been achieved.

Strategy:

Regular monitoring of effluent.

Reduction of effluent generation.

Reuse of liquid effluent generated.

Using the solid waste for useful purpose.

Measures Taken:

Natural draft prill tower of 96 M height for reduced dust emission.

100 M high chimney and ESP in boiler to reduce dust emission.

Cooling tower blow down reduction.

Reuse of steam condensate from ammonia and urea plant in steam generation

plant.

Reuse of inert gas plant effluent in softening plant.

Reuse of waste water from urea plant in cooling tower after treating in Hydrolyser

System.

Reuse of Jacket cooling water of ammonia plant in cooling tower.

Reuse of impure condensate from power plant in cooling tower.

Reuse of raw water pump house ejector water softening plant.

Utilization of Effluent for:

43

- Deashing operation in steam generation plant.

- Irrigation in farm land, green belt etc.

- Dust suppression in ash pond and coal yard.

Use of fly ash for making bricks. Fly ash being supplied to cement manufacturing plant.

ACTIONS IN HAND:

In order to reduce the data water consumption further and also to take care of effluent to be

generated in expansion plant, following two major schemes are being implemented.

1) Sewage Treatment Plant is being installed to treat township sewage. This water

after treatment will be used in plant and raw water consumption is expected to

reduce by about 3000 m3/day. It is expected to be completed by June 1997.

2) Reverse Osmosis Plant will be put up with its pretreatment along with DM plant

effluent segregation scheme. The segregated DM plant effluent will be first

treated in pretreatment plant to remove these impurities. Treated H2O from

pretreatment section will be finally treated with the help of R.O. membranes to

get the water quality fit for reuse in the plant. Total cost of the plant is expected

to be Rs. 8.51 crores. Plant completion is expected by March 1998.

FIRE & SAFETY:

IFFCO Phulpur believes in the philosophy of “prevention is better than cure”. All

necessary steps are being taken to avoid accidents. All employees are being given

training to avoid accidents. However, to handle any eventualities a team of qualified and

trained personnel with necessary modern facilities are available round the clock. An

incident occurred on 04.05.96 when Naphtha caught fire in ammonia plant and it could

have caused severe damage to the ammonia plant, being a major fire ancient, however the

fire was brought under control within 25 mins. This speaks volumes about the

preparedness of fire fighting staff.

Facilities Available:

44

10 Kms length of fire hydrant line ring with 13 single heated and 13 double

heated ground hydrant and 23 single headed fire escape and internal hydrants.

3 fire tenders equipped with latest fire fighting facilities.

16000 m3 total water storage out of which 8000 m3 water exclusively reversed for

fire fighting only.

3 Motor driven and 2 diesel driven water pumps. Each of 410 m3/h capacity. 1

Motor driven pump of 10m3/h capacity.

Fixed foam system for Naphtha storage area.

Fire jeep and rescue van.

Breathing apparatus – 15

Explosive meter - 10

Gas detectors, O2 meters and smoke detectors.

CONCLUSION

45

IFFCO is the world’s largest cooperative sector in production of fertilizers. It was registered

on November 3, 1967 as a Multi-unit Co-operative Society. IFFCO has production units in

the following places Kalol, Kandla, Phulpur, Aonla, Paradeep in India. Ammonia - urea

complex was set up at Phulpur in the state of Uttar Pradesh in 1981.

In Phulpur IFFCO has two ammonia and two urea plants, a power plant and other offsite

planst like DM plant RO plant water softening plant, cooling tower, ammonia and naphtha

storage. Other useful sites are production and quality control, material handling and bagging.

The Ammonia plant in Phulpur-I is based on MW Kellogs USA technology having

capacity of 1215 MTPD and in Phulpur-II plant is based on Haldor Topsoe’s

Denmark’s technology with a capacity of 1740 MTPD.

The Ammonia Plant in Phulpur-I and Phulpur-II uses RLNG as raw material for feed

and fuel. But there is a provision of using Naphtha also as raw material in Phulpur-II.

The main process steps for production of Ammonia in both the plants are similar and

are briefly: desulphurisation, reforming, shift conversion, CO2 removal by absorption,

methanation and ammonia conversion. Following main reaction takes place in ammonia

conversion.

3H2 + 2N2 → 2NH3

The Urea Plant is based on Snamprogetti’s Ammonia stripping process. The

Phulpur-I plant is having capacity of 2115 MTPD while in Phulpur-II there are two

units with a capacity each of 1515 MTPD.

The process of manufacturing of urea in both the units is same except for Phulpur-II

where all the sections are separate for two streams except for Prilling and waste water

treatment section which are common for both the units.

The reaction of Ammonia and Carbon dioxide to produce urea takes place in two stages

at elevated pressure and temperature.

1) 2NH3 + CO2 = NH2COONH4+ 38.1 Kcal/gm.mole

carbamate

2) NH2COONH4 = NH2CONH2 + H2O -7.1 Kcal/gm.mole

carbamate Urea Water

The Urea production process takes place through the following main operations:

46

Urea synthesis and high pressure recovery. Urea purification and low pressure

recovery. Urea concentration. Urea prilling. Waste Water treatment. Offsite contains all

the auxiliary units supporting the main process units which are ammonia and urea plants.

Offsite comprises of AMF set, IG plant, RO plant, DM plant, Cooling tower plant, water

softening plant etc. Power plant has two sets of turbo generators: TG1 and TG2. TG 1 has

capacity of 12.5 MW and TG2 has capacity of 18 MW. Total requirement of power is 25.17

MW for the whole campus. Computer based ‘Distributed Control Systems’ have been used

in large quantities instead of pneumatic control or electronic analogue control system. DCS is

more accurate, fast in operation, more users friendly more informatics and equipped to take

care of start up and shutdown of plants.

In Urea plant of IFFCO Phulpur expansion, DCS model is CENTUM-CS, supplied by

M/s Yokogawa Blue Star Ltd. India.

The plant is totally echo friendly and has got many recycling processes such as energy

management unit for minimizing the consumption of energy, water treatment plant,

manufacturing of ash bricks etc. Many features of it had got self dependent factors and

thus are responsible for higher order of recycling and award getting performance thus

had got many awards in this field. IFFCO Phulpur believes in the philosophy of

“prevention is better than cure”. All necessary steps are being taken to avoid accidents.

All employees are being given training to avoid accidents. However, to handle any

eventualities a team of qualified and trained personnel with necessary modern facilities

are available round the clock. Thus IFFCO is one of the best examples of modernized

industry in the world.

47

REFERENCES:

INTERNET: WWW.GOOGLE.COM

WWW.WIKIPEDIA.COM

WWW.IFFCO.NIC.IN

BOOKS AND MANUALS:

BASIC TRAINING MANUAL, IFFCO PHULPUR

UREA-1 MANUAL, IFFCO PHULPUR

AMMONIA -2 MANUAL, IFFCO PHULPUR

DRYDEN’S OUTLINES FOR CHEMICAL ENGINEERING.

48