project report vishesh bhadariya

CHAMBAL FERTILIZERS & CHEMICALS LTD.

A TRAINING REPORT

ON

“STUDY OF AMMONIA PLANT-2&

PERFORMANCE OF HEAT EXCHANGER”

SubmittedIn partial fulfilment

For the award of the Degree ofBachelor of Technology (PE)

In

DEPARTMENT OF PETROLEUM ENGINEERINGUNIVERSITY COLLEGE OF ENGINEERING

RAJASTHAN TECHNICAL UNIVERSITYKOTA

REPORT SUBMITTED BY:VISHESH BHADARIYA

B.TECH 4TH YEAR PETROLEUM ENGINEERING

ACKNOWLEDGEMENT

We take this opportunity to express our profound gratitude and record our sense ofobligation to Dr. Praveen Kumar Agrawal, H.O.D., Department of PetroleumEngineering, University College of Engineering (R.T.U ); KOTA (Rajasthan) who hasprovided opportunity for accomplishing our training on “AMMONIA PROCESSING PLANT & PERFORMANCE OF HEAT EXCHANGER” At Chambal Fertilizers & Chemicals limited.

During the perseverance of this project, I was supported by different people, whose names if not mentioned would be inconsiderate on my part.

I would also like to express my sincere gratitude and appreciation to Mr. S.K. Jain (Senior Manager, Ammonia-2 plant) & Mr. A.K.Chhipa (DGM-Electrical deptt.) for his support and guidance in my project work.

I would like to thank my Project Mentor Mr.K.K.PUNJ (HEAD TRAINING) for taking time from their busy schedule and timely assessment that provided me inspiration and valued guidance throughout my training.

I would like to thank Mr. A. K. Saxena (H.R. Department) for helping me during the course of my project.

VISHESH BHADARIYA

CERTIFICATE

It is to be certified that VISHESH BHADARIYA student of THIRD YEAR PETROLEUM ENGINEERING, UCE, RTU ,KOTA successfully carried out this project on “ STUDY OF AMMONIA PLANT-2 & PERFORMANCE OF HEAT EXCHANGER” as the part of their curriculum, a my guidance and completed his industrial training from 03 JUNE to 02 JULY,2014 .

During project they showed a learning aptitude and performed satisfactorily.

I wish them a bright future.

(Mr. K.K. PUNJ)

TRAINING HEAD

Plant Ammonia-2

Chambal Fertilizers and chemicals Ltd. Kota

TABLE OF CONTENTS

S.NO. CONTENTS PAGE NO.

1. AMMONIA-2 PROCESS DESCRIPTION 1-34

• THE OVERVIEW

• NG Composition

• CATALYSTS ROLE

• MAJOR REACTIONS IN AMMONIA PROCESS

• Reforming of the Feed Stock

• Reforming Catalysts

• Shift Conversion

• Catalyst

• Shift Reaction Catalysts

• Operating Parameters

• CO2 REMOVAL (Benfield Section)

• Methanation Reaction

• COMPRESSOR SECTION

• AMMONIA SYNTHESIS SECTION

• REFRIGERATION CIRCUIT

• AMMONIA SCRUBBER &DISTILLATION COLUMN

• FLARE SYSTEM

• UTILITIES OF AMMONIA PLANT

2. THEORY OF HEAT EXCHANGER 35-43

• INTRODUCTION

• PURPOSE OF THE PERFORMANCE TEST

• PERFORMANCE TERMS AND DEFINITIONS

• NOMENCLATURE

3. EFFECTIVENESS OF HEAT EXCHANGER

• EA-502

• EA-706

• EA-711

• EA-704

AMMONIA- 2 PROCESS DESCRIPTION:

Ammonia is one of the main raw materials for the manufacture of Urea and Di- Ammonium Phosphate, which are the backbone of the farming sector in India. Ammonia also has many other uses in chemical industry. Main raw materials for the manufacture of Ammonia are hydrocarbons like natural gas, naphtha and low sulphur high stock. Coal is also used as a raw material for Ammonia manufacture.

THE OVERVIEW...

• A. Naphtha Sweetening Section

• B. Desulphurization Section

• 1. Hydrogenation

• 2. Adsorption

• C. Reforming Section

• 1. Primary Reformer

• 2. Secondary Reformer

• D. Gas Purification Section

• 1. Shift Conversion

• 2. CO2 removal ( Benfield Section)

• 3. Methanation

• E. Compressor Section

• F. Ammonia Synthesis and Refrigeration Section

• G. Purge Gas Wash Section

• H. Flare System

• I. Utilities

• 1. Auxilliary Boiler

• 2. Cooling Water Circulation System (ACT/ UCT)

• 3. Emergency Diesel Generator

NG Composition:

Design Actual

CH4 85.78 % 90.5 %

C2H6 07.78 % 06.0 %

C3H8 01.56 % 2.25 %

n-C4H10 00.03 % 00.54 %

i-C4H10 00.06 % 00.4 %

CO2 04.70 % 0.0 %

N2 00.09 % 0.007 %

LCV(Kcal/Sm3) 8450 8970

• Ammonia manufacturing process involves lot of chemical reactions taking place in the gaseous phase over the catalytic beds.

• The main reactions taking place in the Ammonia manufacturing process involving reforming process are as follows:

• 1. Hydrogenation and desulphurisation of

feedstock

• 2. Reforming of the feedstock

• 3. Shift conversion reaction

• 4. Carbondioxide Removal

• 4. Methanation reaction

• 5. Ammonia Synthesis reaction

CATALYSTS ROLE:

• Catalysts play an important role in each of the reactions involved in the Process. Catalysts help in lowering the severity of the temperature and pressure conditions required for the reactions, thus reducing the energy cost for producing Ammonia.

MAJOR REACTIONS IN AMMONIA PROCESS:

H drogenation&Desulphurisation of feed Stock:

• RSH + H2 = RH + H2S (R is a radical of hydrocarbon.)

• ZnO + H2S = ZnS + H2O

Hydrogenation and Desulphurisation Catalysts:

• In the hydrogenation reaction sulphur present along with the hydrocarbon feedstock is converted to hydrogen sulphide. The reaction involved in the process is

• RSH + H2 = RH + H2S, where R is a radical of hydrocarbon.

• CoMoX and NiMoX catalysts are generally used for the hydrogenation reaction. The catalyst is in the shape of extrudates.

• In the desulphurisation step hydrogen sulphide formed in the hydrogenation reaction is absorbed in the Zinc Oxide bed. Zinc Oxide catalyst is in the shape of extrudates.

• The optimum operating range of the temperature for the above two reactions is from 370°C to 390°C.

Reforming of the Feed Stock :

• CnH2n+2 + 2H2O = Cn-1H2n+CO2+3H2-heat

• CH4 + 2H2O = CO2 + 4H2- Heat

Reforming Catalysts:

The main constituent of the Reforming catalysts is nickel oxide. This catalyst converts hydrocarbons in presence of steam to carbon dioxide, carbon monoxide and hydrogen. The reaction involved in the process is

• CnH2n+2 + 2H2O= Cn-1H2n+CO2+3H2-heat

• CH4 + 2H2O = CO2 + 4H2- Heat

• CO + H2 = CO2 + H2 + heat

• Catalyst is generally cylindrical in shape with multiple holes. Catalysts used in Primary Reformer are smaller in size as compared to catalysts used in Secondary Reformer. The operating pressures for Primary Reformer catalysts vary from 32 Kg/cm2 to 39 Kg/cm2 and the operating temperatures range from 770°C to 810°C. The operating temperatures for Secondary Reformer range from 980°C to 1020°C.

Shift Conversion:

Gas leaving Reforming section has 13% CO and

10% CO2. CO is converted to CO2 in two shift

converters, HTS

(DC-301) and LTG/ LTS (DC-302/ DC-303).

Reaction- Exothermic Reaction

CO+H2O = CO2 + H2 ; H1-H2=-41 kJ/mol

Catalyst:

HTS : ICI 71-5 :73 M3 (Iron Cromia based)

Supplier : Johnson Matthey

LTG/ LTS : 100 M3 (Cu, Zn & Al2O3)

Supplier : Suede Cheme

Shift Reaction Catalysts:

In the Shift Conversion reaction carbon monoxide formed during the Reforming reaction is converted to carbon dioxide in the presence of steam. The reaction involved in the process is

• CO + H2O = CO2 + H2 + Heat

• Shift Conversion reaction is carried out in two steps. First is the high temperature shift conversion and second is the low temperature shift conversion. The two-step conversion is based upon the Le- Chatilier principle. The main constituent of the catalyst used for HT shift conversion is Iron and it is in the form of tablets. Copper is the main constituent of the low temperature shift conversion and it is also available in the tablet shape. The HT shift catalyst operate in the temperature range of 370°C to 450°C and LT shift catalyst operating temperature range is 200° to 220°C.

Operating Parameters :

• Temp. : HTS (In/Out): 365/440 deg C

LTS (In/Out): 210/234 deg C

• CO Slip- HTS: 2.9 mole%

LTS: 0.25 mole%

The reacted part of the CO increases the H2 yield with simultaneous formation of CO2, which is more easily removable.

CO2 REMOVAL (Benfield Section):

Composition:

K2CO3 : 29 % wt. Avg.

Total V : 1.1 % (Corrosion Inhibitor)

ACT-1 : 0.85 % (Activator)

Reaction:

K2CO3 + CO2 + H2O = 2KHCO3

Absorption- (High Pressure Chemisorptions)

The gas is passed through CO2 Absorber (DA-401), which is a column containing stainless steel packing material distributed in beds. In the absorber the gas flows upwards against a descending stream of Benfield solution.

Regeneration:

CO2 Stripper (DA-402) : 0.85 Kg/Cm2g

Heat for regeneration:

EA-404 : Provides steam for Regeneration

EA-401 : Lean Solution Reboiler

FA-404 : Multistage Flash vessel

CO2 from stripper is sent to Urea-2 plant as Raw material for urea production.

Methanation:

CO + 3H2 = CH4 + H2O + heatCO2 + 4H2 = CH4+ 2H2O + heat

Methanation Reaction:

In this reaction carbon monoxide and carbon dioxide present along with synthesis gas are converted back to methane as these acts as poisons for the ammonia synthesis reaction. The main constituent of

the catalyst used for methanation reaction is nickel oxide and it is available in the form of spheres. The reaction involved in the process is

CO + 3H2 = CH4 + H2O + heat

CO2 + 4H2 = CH4+ 2H2O + heat

The catalyst operates in the temperature range of about 300°C to 340°C.

COMPRESSOR SECTION:

GB-201 Air compressor

• Supplied by –Hitachi Ltd

• No. of stages – 4 (centrifugal compressor)

• Driver – Steam

• Rated Output – 14100 KW

• Discharge pressure -40 kg/cm2

GT-201 Air compressor turbine

• Supplied by – Siemens


• Type – Extraction cum condensing

• Inlet steam – 105 Kg/cm2

• Extraction steam – 42.7 Kg/cm2

• Exhaust – 0.16 kg/cm2

GB – 601 (SYN GAS COMPRESSOR)

• Supplied by – Mitsubishi

• No. of stages – 4

• Driver – steam


GT-601 ( SYN GAS COMPRESSOR TURBINE)

• Supplied by – Mitsubishi

• Stages – 7

• Type –Extraction cum condencing

• Inlet steam – 105 kg/cm2

• Extraction steam – 42.7 kg/cm2

• Exhaust – 0.16 kg/cm2

GB – 701 (REFRIGERATION COMPRESSOR)

• Supplied by – Hitachi Ltd.

• No of stages – 4

• Driver – steam

• Driver rated output – 8260 kw

• Discharge press. – 18 kg/cm2

GT-701 is SHIN NIPPON Ltd.

• Condensing and Admission steam type.

• Inlet steam Pr. 41.7 kg/cm2

• Exhaust steam Pr. 0.16 Kg/cm2

• No. of stages -6

AMMONIA SYNTHESIS SECTION:

Ammonia Converter (DC-701):

Horizontal converter with three catalyst beds and one internal heat exchanger.

Catalyst Details:

KM1/KM1R: 57/28 M3

Supplier: Topsoe

Operating Parameters:

Temp. (In/Out): 220/450 deg C

Pressure : 177 Kg/Cm2g

H2/N2 Ratio : 2.95 – 3.0 mole/mole

Reaction- Exothermic:

3H2 + N2 = 2NH3 ; H1-H2= -46 KJ/MOL

Conversion : 30% approx. per pass

Factors affecting Ammonia conversion:

• Ammonia conc. at Converter Inlet- Low

• Inert Gases (Argon and Methane) - Low

• H2/N2 Ratio - Optimum

• Reaction temperature - Low

• Circulation Rate - High

• Operating Pressure - High

Catalyst poisons:

• Oxygen Compounds: CO2, CO & H2O (Max. limit at Converter i/L = 10 ppm)

• Chlorine: BFW System

REFRIGERATION CIRCUIT :

• Purpose-

• To condense Ammonia produced in the Ammonia Converter.

• Refrigeration Circuit-

Unitized chiller for easier operation

• Process Detail-

The four stage refrigeration system provides refrigeration for ammonia condensation. The refrigeration consist of two case centrifugal compressor with intercoolers, refrigerant condenser, refrigerant receiver & four flash drum in unitized chillers.

AMMONIA SCRUBBER &DISTILLATION COLUMN:

• Uncondensed gas from refrigerant receiver, flashed gases from Ammonia let down & purge gas from synthesis loop sent to ammonia scrubber for ammonia recovery. Ammonia is absorbed by water.

• Vapor from ammonia scrubber used as fuel gas.

FLARE SYSTEM:

• There are three main flare system that collect

• gases & vented

• The first system collect hot gases venting from the

• process equipment associated with front end ammonia

• plant.

• The second system collect cold gases from synthesis

• section

• The third system collect gases from the hydrotreater

• Area

UTILITIES OF AMMONIA PLANT:

Theory of heat exchanger:

Introduction :

Heat exchangers are equipment that transfer heat from one medium to another. The proper design, operation and maintenance of heat exchangers will make the process energy efficient and minimize energy losses. Heat exchanger performance can deteriorate with time, off design operations and other interferences such as fouling, scaling etc. It is necessary to assess periodically the heat exchanger performance in order to maintain them at a high efficiency level. This section comprises certain proven techniques of monitoring the performance of heat exchangers, coolers and condensers from observed operating data of the equipment.

Purpose of the Performance Test :

To determine the overall heat transfer coefficient for assessing the performance of the heat exchanger. Any deviation from the design heat transfer coefficient will indicate occurrence of fouling.

Performance Terms and Definitions:

Overall heat transfer coefficient, U

Heat exchanger performance is normally evaluated by the overall heat transfer coefficient U that is defined by the equation

Q=U x A x LMTD

Where Q = Heat transferred in kCal/hrA = Heat transfer surface area in m2

LMTD = Log Mean Temperature Difference in 0C

U = Overall heat

When the hot and cold stream flows and inlet temperatures are constant, the heat transfer coefficient may be evaluated using the above formula. It may be observed that the heat pick up by the cold fluid starts reducing with time.

Nomenclature :

A typical heat exchanger is shown in figure with nomenclature

Heat duty of the exchanger can be calculated either on the hot

side fluid or cold side fluid as given below.

Heat Duty for Hot fluid, Qh = W x Cphx (Ti-To) ………..Eqn-1,

Heat Duty for Cold fluid, Qc = w x Cpc x ( to-ti) ………...Eqn-2

If the operating heat duty is less than design heat duty, it may be due to heat losses, fouling in tubes, reduced flow rate (hot or cold) etc. Hence, for simple performance monitoring of exchanger, efficiency may be considered as factor of performance irrespective of other

parameter. However, in industrial practice, fouling factor method is more predominantly used.

Effectiveness of heat exchanger:

EA-502

Sr. no.

Physical quantities

Shell side fluid (hot)(methanator effluent)

Tube side fluid (cold)(cooling water)

1 Mass flow rate (kg/hr)

75691 1007000

2 Temperature (°c) Tin Tout Tin Tout

106.4 41 36 413 Specific heat

(kcal/kg °c).803 .859 1

4 Design pressure (kg/cm2)

29.8 4

Design parameters:

Sr. no.

Physical quantities

Shell side fluid (hot)(methanator effluent)



83462 1180000


80 37 34 423 Specific heat

(kcal/kg °c).803 .859 1

Operating parameters:

CALCULATION:

Qactual=MhCh(Th1-Th2)

= 83462 × 0.831 × (80-37)

=2982347 kcal/hr

Qmax=Cmin(Th1-Tc1)

Cmin=MhCh

= 0.831 × 75691

=62899 kcal/kg °c

Qmax= 62899 × (106.4-36)

=4428089.6 kcal/hr

Effectiveness ofEA-502 =Qactual÷ Qmax

=MhCh(Th1-Th2)÷ Cmin(Th1-Tc1)

=2982347 ÷ 4428089.6

Effectiveness of EA-502=0.6735

=67.35%

EA-706

Sr. no.

Physical quantities

Shell side fluid (hot)(ammonia+innerts)



84283 8750000

2 Temperature (°c)

Tin Tout Tin Tout

117 43 36 38.93 Specific heat

(kcal/kg °c).621 .708 1


70.1 4

Design parameters:

Sr. no.

Physical quantities

Shell side fluid (hot)(ammonia+innerts )



72000 4900000

2 Temperature (°c)

Tin Tout Tin Tout


(kcal/kg °c).621 .708 1


CALCULATION:


= 72000× 0.665× (104-36)

= 3255840 kcal/hr

Qmax=Cmin(Th1-Tc1)

Cmin=MhCh

= 0.665 × 84283

= 56048.2 kcal/kg °c

Qmax= 56048.2 × (117-36)

= 4549903.79 kcal/hr



= 3255840÷ 4549903.79

Effectiveness of EA-502= 0.7177

= 71.77%

EA-711

Sr. no.

Physical quantities

Shell side fluid (hot)(ammonia+innerts)



25586 87000

2 Temperature (°c)

Tin Tout Tin Tout

73.8 41 36 413 Specific heat

(kcal/kg °c).533 .522 1


3.5 4

Design parameters:

Sr. no.

Physical quantities

Shell side fluid (hot)(ammonia+innerts )



22800 74000

2 Temperature (°c)

Tin Tout Tin Tout


(kcal/kg °c).533 .522 1


CALCULATION:


= 22800 × 0.527× (74-36)

= 456592.8 kcal/hr

Qmax=Cmin(Th1-Tc1)

Cmin=MhCh

= 0.527 × 25586

= 13483.822 kcal/kg °c

Qmax= 13483.822 × (73.8-36)

= 509688.47 kcal/hr



=456592.8 ÷ 509688.47


= 89.58%

EA-704

Sr. no.

Physical quantities

Shell side fluid (hot)(convertor effluent)



286400 1434550


68.1 41 36 40

3 Specific heat (kcal/kg °c)

.763 .768 1


70.1 4

Design parameters:

Sr. no.

Physical quantities

Shell side fluid (hot)( convertor effluent )



254000 870000



(kcal/kg °c).763 .768 1


CALCULATION:


= 254000 × 0.765× (75-41)

= 6606540 kcal/hr

Qmax=Cmin(Th1-Tc1)

Cmin=MhCh

= 0.765 × 286400

= 219096 kcal/kg °c

Qmax= 13483.822 × (68.1-36)

= 7032981 kcal/hr



= 6606540÷ 7032981


= 93.94%

project report vishesh bhadariya

Documents

manufacture of ammonia

ammonia manufacture

study of ammonia plant

ammonia process reforming

reforming section

training report

theory of heat exchanger

desulphurization section