SARDAR VALLABHBHAI NATIONAL INSTITUTE OF

TECHNOLOGY

SURAT

A PROJECT REPORT ON

INDUSTRIAL PRODUCTION OF MELAMINE

PREPARED BY

Shubham Yadav (U12CH042) Amit Gomey (U12CH026)

GUIDED BY

Dr. A. K. Jana

Assistant Professor

Chemical Engineering Department

SVNIT, Surat

1

CERTIFICATE

This is to certify that the B. Tech. IV (7th Semester) PROJECT REPORT

Entitled “MELAMINE” presented & submitted by Candidate Shubham Yadav bearing

Roll No.U12CH042 and Amit Gomey Bearing Roll No.U12CH026 in the partial

Fulfilment of the requirement for the award of degree B.Tech. in Chemical Engineering.

They have successfully and satisfactorily completed their Project Exam in all respect. We,

Certify that the work is comprehensive, complete and fit for evaluation.

Dr. A. K. Jana

Assistant Professor

Project Guide ___________

PROJECT EXAMINERS:

Examiner Signature with date

Examiner 1 __________________

Examiner 2 __________________

Examiner 3 __________________

Department Seal

2

ACKNOWLEDGEMENT

We take this opportunity to express our gratitude and indebtedness to Dr. A.K. Jana of the Chemical

Engineering department, S.V.N.I.T, Surat for his valuable guidance and

Encouraging attitude at all times. We would also like to thank the head of the department

Dr. Jigisha K. Parikh for giving us a chance to do a Project on the given topic. We are also thankful to

S.V.N.I.T Surat and its staff for providing us this opportunity which helped us a lot in our quest

for gaining knowledge and going a long way in making this Project report successful.

3

CONTENTS

S.No. Topic Page No.

1 CERTIFICATE 1

2 ACKNOWLEDGEMENT 2

3 ABSTRACT 4

4 CHAPTER 1: INTRODUCTION 5

5 CHAPTER 2: DEMAND AND SUPPLY OF PRODUCT 7

6 CHAPTER 3: PROCESS SELECTION AND DESCRIPTION 9

7 CHAPTER 4: FLOW DIAGRAM FOR THE PROCESS 15

8 CHAPTER 5: MATERIAL BALANCE 16

9 CHAPTER 6: ENERGY BALANCE 20

10 REFERENCES 29

4

ABSTRACT

Melamine is a very important industrial chemical compound that find its

application and uses in most of the day-to-day products. It is stable, easily combine

with other chemicals, can be polymerized, and an excellent fire retardant.

Melamine is produced with the help of two most desired process, one is Lurgi’s

and other is Eurotecnica’s methods. Here we will explore the methods designed

by Eurotecnica i.e. the HP process.

It requires no catalyst, reaches similar purities as in LP. The advantage

of this process is that there are no concerns regarding the catalyst and fines, and

that the dry off gas at high pressure enables it to be easily integrated in a Urea

plant. Due to the high pressures involved, this technology is more suitable for

low production capacities, whereas the low pressure process is preferred for

large production capacity

5

CHAPTER 1: INTRODUCTION

Melamine is a non-toxic and non-hazardous chemical compound,

mainly used in the manufacturing of melamine/formaldehyde resins that fit into

a large variety of applications, such as laminates, particleboards and

thermosetting plastic. Other applications include paints, glues and flame-

retardants.

Three main characteristics make melamine a versatile chemical compound:

1. Stability, making it resistant to chemical, thermal and physical degradation;

2. Structure, allowing it to be combined with other chemicals and chemical

compounds, particularly formaldehyde and other monomers, in a wide variety

of chemical reactions and polymerisation;

3. Nitrogen content (66%wt), providing excellent fire retardant properties. When

exposed to intense heat, nitrogen is released and inhibits the combustion.

The German word melamine was coined by combining the words: melam (a

derivative of ammonium thiocyanate) and amine. [1]

Structure of Melamine

2-D and 3-D Structure of Melamine [2]

6

PROPERTIES OF MELAMINE [3]

IUPAC Name 1,3,5 triazine2,4,6 triamine

Molecular Formula C3H6N6

Molecular Weight 126.11994 g/mol

Physical Description 1. Dry Powder

2. Dry Powder, Wet Solid

3. Liquid

4. Other Solid

5. Pellets, Large Crystals

Colour White, monoclinic crystals

Boiling Point 354 deg C

Solubility Very slightly soluble in hot alcohol;

insoluble in ether

Density 1.573 at 14 deg C

Vapour Density 4.34

Vapour Pressure 50 mmHg at 599 °F

Decomposition Decomposes at 345°C, Dangerous; when

heated to decompose, emits highly toxic

fumes of /nitrogen oxides and hydrogen

cyanide

Heat of Combustion 1967 kJ/mol at 25 deg C

7

USES [4]

Industry Uses

1. Adhesives and sealant chemicals

2. Dyes

3. Flame retardants

4. Intermediates

5. Laboratory chemicals

6. Paint additives and coating additives not described by other categories

7. Pigments

8. Plasticizers

Consumer Uses

1. Adhesives and Sealants

2. Building/Construction Materials Wood

3. and Engineered Wood Products

4. Floor Coverings

5. Furniture and Furnishings not covered elsewhere

6. Paints and Coatings

8

CHAPTER 2: DEMAND AND SUPPLY OF PRODUCT

Melamine is used almost exclusively in the manufacture of melamine-

based thermosetting resins, except in certain fire-retardant formulations, where

melamine crystal is utilized. The other important, but significantly smaller, use

is in the production of flame retardants, especially for polyurethane foams. The

high nitrogen content of both the resin and the crystalline monomer is the key

desirable property that allows for the frequent use of melamine in flame-

retardant formulations.

Overall economic performance will continue to be the best indicator of

future demand for melamine. Demand in most downstream markets is greatly

influenced by general economic conditions. As a result, demand largely follows

the patterns of the leading world economies. The major end-use markets include

construction/remodelling, automotive production and original equipment

manufacturer. [5]

The following pie chart shows world consumption of melamine:

9

China is the largest single participant in the melamine market, accounting for half

of world consumption in 2013; it also accounted for 69%, 62%, and 39% of world capacity,

production, and exports, respectively, in 2013. This trend is expected to continue during

2013–2018, as strong growth in Chinese consumption will result in additional capacity and

increased production.

During the next few years, global melamine consumption will grow at a rate of

about 4% per year, driven by China’s growth and increases in other regions such as other

Asian countries (not including Japan), Central and Eastern Europe, and the Middle East.

10

Manufacturers in India and Costs [6]

Sr. No. Manufacture Cost

1 Techno Sales Corporation Rs 130/kg

2 Melamine (Mfg. by Gujarat State Fertilizer

company Ltd – Vadodara)

Not Available

3 Arrow Fine Chemicals Not Available

4 Alliance Global Not Available

5 Jainco Chemicals Pvt. Ltd.

Rs 119/kg

11

Material Safety Data Sheet

Melamine MSDS [19]

12

13

14

CHAPTER 3: PROCESS SELECTION AND DESCRIPTION

Today most industrial manufacturers use urea in the following reaction to

produce melamine:

6 CO(NH2)2→ C3H6N6 + 6 NH3 + 3 CO2

It can be understood as two steps.

STEP I: Urea decomposes into cyanic acid and ammonia in an endothermic

reaction:

6CO(NH2)2→ 6HCNO + 6NH3

Then, cyanic acid polymerizes to form cyanuric acid which condenses with

the liberated ammonia forming melamine which releases water which then

reacts with cyanic acid present (which helps to drive the reaction) generating

carbon dioxide and ammonia.

STEP II:

6HCNO → C3H6N6 + 3CO2

The second reaction is exothermic but the overall process is endothermic.

The above reaction can be carried out by either of two methods:

1. catalysed gas-phase production or

2. high pressure liquid-phase production

The main characteristics of the continuous processes actually employed are

listed in the following table: [7]

15

The LP process in vapour phase is a catalytic process in which the

decomposition of molten urea and the synthesis of melamine takes place in

a fluidized catalytic reactor. The effluent is quenched with water (recovering

the product in a slurry) or with cold gas, and the off gas is sent to the

recovery and treatment unit. The slurry (in case of liquid quenching) is

driven though a filter (to remove catalyst fines) and finally to a

crystallization equipment, where the final product is obtained after a

centrifuge and a dryer with a purity above 99,8%. In the following process

flow diagram by Lurgi, the quenching is carried out with gas and therefore

there is no drying unit:

Gas Quench LP Melamine by Lurgi. [8]

The HP process in liquid phase (or Shortened Liquid Phase SLP) requires

no catalyst, reaches similar purities as in LP, and consists of a high pressure

section, in which molten urea is converted to Melamine in the reactor

followed by a quenching step and the recovering of the off gas though a

stripper. In the low pressure section the hydrolyser and filtration lead to a

crystallization unit from which the Melamine slurry is dried and stored. The

figure below shows schematically these steps:

16

Liquid Quench HP Melamine by Eurotecnica [9]

PROCESS SELECTION

Here we will proceed with Liquid Quench HP Melamine by

Eurotecnica.

The advantage of this process is that there are no concerns regarding

the catalyst and fines, and that the dry off gas at high pressure enables it to

be easily integrated in a Urea plant. Due to the high pressures involved, this

technology is more suitable for low production capacities, whereas the low

pressure process is preferred for large production capacity. [10]

PROCESS DESCRIPTION [11]

1. In this method, molten urea is introduced onto reactor after in the

form of molten urea, for reaction. Hot ammonia gas is also present

to inhibit deammonization. The effluent then is cooled. Ammonia

and carbon dioxide in the off-gas are separated from the melamine-

containing slurry.

2. The slurry is further concentrated by quenching, hydrolysed and

crystallized to yield melamine.

17

3. Major manufacturers and licensors such as Orascom Construction

Industries, BASF, and Eurotecnica have developed some

proprietary methods.

4. The off-gas contains large amounts of ammonia. Therefore,

melamine production is often integrated into urea production, which

uses ammonia as feedstock.

5. Crystallization and washing of melamine generates a considerable

amount of waste water, which is a pollutant if discharged directly

into the environment.

6. The waste water may be concentrated into a solid (1.5–5% of the

weight) for easier disposal.

7. The solid may contain approximately 70% melamine, 23%

oxytriazines (ammeline, ammelide, and cyanuric acid), 0.7%

polycondensates (melem, melam, and melon).

8. In the Eurotecnica process, however, there is no solid waste and the

contaminants are decomposed to ammonia and carbon dioxide and

sent as off gas to the upstream urea plant; accordingly, the waste

water can be recycled to the melamine plant itself or used as clean

cooling water make-up.

Single-stage, liquid-phase non catalytic reaction. The reactor is as

simple, flexible and reliable as a heat exchanger.

There are no recycle loops, no compressors, no fluid bed nor catalyst

to be taken care of.

The very high pressure inside the reactor allows to keep the pressure

at high levels also in the downstream equipment and in the stream of off

gases going back to the urea plant, thus greatly simplifying the

integration of the melamine plant in a fertilizer complex.

Separation and purification based on intrinsic properties of the

products coming out from the reactor, without addition of further

chemicals.

The unit operations of the separation and purification step are based

on Eurotecnica’s deep knowledge of the equilibriums among ammonia

and the other products coming out from the reactor.

18

No additional expenses for chemicals are required, nor are salts to

be disposed of found in the effluents.

Zero discharge, total recovery of products and co-products. Reaction

products in all streams coming out from the plant are recovered either as

melamine or decomposed to ammonia and carbon dioxide and recycled

with the off gases to the urea plant.

No valuable product is wasted and no solids, liquid or gaseous

pollutants are released to the environment.

RAW MATERIALS

1. Urea solution

2. Ammonia

UTILITIES

1. Demineralised water

2. Steam

3. Cooling water

REACTION TEMPERATURE: 360-440 C

REACTION PRESSURE: 80-120 bar

REACTOR TYPE: Simple Reactor

OVERALL REACTION: Highly Endothermic

BY-PRODUCTS FORMED

1. Melem (C6N10H6)

2C3N6H6 C6N10H6 + 2NH3

2. Melam (C6N11H6)

C3N6H6 C6N11H6 + NH3

3. Melon (C18N28H12)

6C3N6H6 C18N28H12 + 8NH3

The formation of these by-products can be supressed by applying

process conditions of high NH3 pressure and temperature.

SIDE PRODUCTS FORMED

19

These products are formed due to partial or complete hydrolysis of

thee amino groups of C3N6H6.

1. Ammeline

C3N6H6 + H2O C3N5OH5 + NH3

2. Ammelide

C3N6H6 +2H2O C3N4O2H4 + 2NH3

3. Cyanuric Acid

C3N6H6 +3H2O C3N3O3H3 + 3NH3

20

CHAPTER 4: FLOW DIAGRAM FOR THE

PROCESS [12]

21

CHAPTER 5: MATERIAL BALANCE

Requirement of Melamine: 1875 kg/h = 46 ton/h

Purity of final products: 100% (by weight)

Therefore, total mass of final product:

(1875× (100/100)) = 1875 Kg/h. = 1.875 ton/h.

The material balance can be done considering the following reactions:

REACTION 01: 6CO(NH2)2→ 6HCNO + 6NH3

REACTION 02: 6HCNO → C3H6N6 + 3CO2

OVERALL REACTION

6 CO(NH2)2→ C3H6N6 + 6 NH3 + 3 CO2

MOLECULAR WAIGHT DATA [13]

Molecular weight of Melamine: 84.09 kg/kmol

Molecular weight of Ammonia: 17.03 kg/kmol

Molecular weight of Carbon di-oxide: 44.010kg/kmol

Molecular weight of Urea: 60.05 kg/kmol

Consider first of all reaction number – 02

6HCNO → C3H6N6 + 3CO2

Kilo-moles of Melamine = (1875/84.099) = 22.295 kmol/h.

Since 100% purity required so final kilo- moles of Melamine: (22.295×1) = 22.295 kmol/h

Kilo moles of carbon dioxide = (3×22.295) = 66.885 kmol/h.

Kilo moles of HCNO= (6×22.295) = 13.77 kmol/h

22

Consider first of all reaction number – 01

6CO(NH2)2→ 6HCNO + 6NH3

Kilo-moles of HCNO = 133.77 kmol/h. (from above)

Kilo moles of NH3= (6/6×133.77) kmol/h.

Kilo moles of Urea= (133.77× 1) kmol/h

Mass Flow rate of reactants and products in kg/h

Urea = 8033.59 kg/h

Melamine = 1875 kg/h

CO2 = 2943.58 kg/h

NH3 = 2278.17 kg/h

Urea= 133.77 kmol/h

CO2 = 66.885 kmol/h

Melamine = 22.295 kmol/h

NH3 = 133.77 kmol/h

REACTOR

23

QUENCHING

The products from the reactor are fed for quenching at a temperature of 385oC

and water is sprayed. Then inert gases are introduced into the sprayed water

zone, the resulting melamine in the form of slurry which is collected at the pool

below the zone of sprayed water at 72 oC. [14]

INLET (at 385 deg Celsius)

CO2 = 66.885 kmol/h

Melamine = 22.295 kmol/h

NH3 = 133.77 kmol/h

OUTLET (at 72 deg Celsius)

CO2 = 66.885 kmol/h

Melamine = 22.295 kmol/h

NH3 = 45.41 kmol/h

CO2 = 66.885 kmol/h

Melamine = 22.295 kmol/h

NH3 = 133.77 kmol/h

CO2 = 66.885 kmol/h

Melamine = 22.295 kmol/h

NH3 = 45.41 kmol/h

QUENCHING

24

STRIPPING

The stripper strips off about 95% of ammonia and 85% of CO2, which

is again recycled and leaving end product with no more than 0.2% of both

ammonia and CO2. [15]

Feed: CO2, NH3, C3H6N6

Product: CO2, NH3, C3H6N6

INLET (at 120 deg Celsius)

CO2 = 66.885 kmol/h

Melamine = 22.295 kmol/h

NH3 = 45.41 kmol/h

OUTLET (70 deg Celsius)

CO2 = 0.02 kmol/h

Melamine = 22.295 kmol/h

NH3 = 0.00454 kmol/h

CO2 = 0.02 kmol/h

Melamine = 22.295 kmol/h

NH3 = 0.00454 kmol/h

CO2 = 66.885 kmol/h

Melamine = 22.295 kmol/h

NH3 = 45.41 kmol/h

STRIPPER

25

CHAPTER 5: ENERGY BALANCE

Cp values of molecules at different temperature can be calculated by using the

following equation Cp/R = A + (B*T) + (C*T2) + (D*T-2) [16] Where, T =

Temperature (in Kelvin) a, b, c, d are constants.

ENERGY BALANCE FOR SYNTHESIS REACTION:

Inlet Temperature: 400 C

Outlet Temperature: 390 C

Feed: Urea

Product: CO2, NH3, C3H6N6

Inlet:

Outlet:

CO2: Cp=8.314(5.457+ (1.045*10-3*663.15) +(-1.157*105*(663.15)-2)=48.15 kJ/Kmol K

NH3: Cp=8.314(3.578+(3.020*10-3*663.15)+(-0.154*105*(663.15)-2)=46.11 kJ/Kmol K

Species A B*103 C*106 D*10-2

CO2 5.457 1.045 0 -1.157

NH3 3.578 3.020 0 -0.154

Species m (kmol/h) Cp (kJ/kmol h) T ( K) Qin (kJ)

Urea 133.77 121.5[17] 673.15 10940744

26

Therefore, Qin – Qout = 10940744 – (2508706.8+2692335.62+1787054.4) = 3952647.18

kJ

where +ve sign indicates endothermic reaction.

ENERGY BALANCE FOR QUENCHING SECTION:

Inlet Temperature: 385 C

Outlet Temperature: 72 C

Feed: CO2, NH3, C3H6N6

Product: CO2, NH3, C3H6N6

Inlet:

CO2: Cp=8.314(5.457+(1.045*10-3*658.15)+(-1.157*105*(658.15)-2)=48.87 kJ/Kmol K

NH3: Cp=8.314(3.578+(3.020*10-3*658.15)+(-0.154*105*(658.15)-2)=44.052 kJ/Kmol K

Species m (kmol/h) T (K) Cp (kJ/Kmol K) Qout (kJ)

CO2 66.885 663.15 40.29 1787054.4

NH3 133.77 663.15 30.35 2692335.62

C3H6N6 22.295 663.15 169.68[18] 2508706.8

Species m (kmol/h) T (K) Cp (kJ/Kmol K) Qin (kJ)

CO2 66.885 658.15 48.87 2151275.13

NH3 133.77 658.15 44.052 3878370.04

C3H6N6 22.295 658.15 208.26[18] 3055893.58

27

Outlet:

CO2: Cp=8.314(5.457+ (1.045*10-3*345.15) + (-1.157*105*(345.15)-2)=40.29 kJ/Kmol K

NH3: Cp=8.314(3.578+ (3.020*10-3*345.15) + (-0.154*105*(345.15)-2)=30.35 kJ/Kmol K

Therefore, Qin – Qout = (2151275.13+3878370.04+3055893.58

– (929970.003+475652.061+1305707.83) = 6374208.86 kJ

where +ve sign indicates endothermic reaction.

ENERGY BALANCE FOR STRIPPING SECTION:

Inlet Temperature: 393.15 C

Outlet Temperature: 343.15 C

Feed: CO2, NH3, C3H6N6

Product: CO2, NH3, C3H6N6

Inlet:

CO2: Cp=8.314(5.457+ (1.045*10-3*393.15) + (-1.157*105*(393.15)-2)=43.31kJ/Kmol K

NH3: Cp=8.314(3.578+ (3.020*10-3*393.15) + (-0.154*105*(393.15)-2)=38.79 kJ/Kmol K

Species m (kmol/h) T (K) Cp (kJ/Kmol K) Qout (kJ)

CO2 66.875 345.15 40.29 929970.003

NH3 45.407 345.15 30.35 475652.061

C3H6N6 22.295 345.15 169.68[18] 1305707.83

28

Outlet:

CO2: Cp=8.314(5.457+ (1.045*10-3*343.15) + (-1.157*105*(343.15)-2)=43.31kJ/Kmol K

NH3: Cp=8.314(3.578+ (3.020*10-3*343.15) + (-0.154*105*(343.15)-2)=38.79 kJ/Kmol K

Therefore, Qin – Qout = (1138702.46+692469.85+1647838.61 –

(280.90259+58.0785493+1292174.39) = 2186498kJ

where +ve sign indicates endothermic reaction.

Species m (kmol/h) T (K) Cp (kJ/Kmol K) Qin (kJ)

CO2 66.875 393.15 43.31 1138702.46

NH3 45.407 393.15 38.79 692469.85

C3H6N6 22.293 393.15 188.013 1647838.61

Species m (kmol/h) T (K) Cp (kJ/Kmol K) Qout (kJ)

CO2 0.02 343.15 40.93 280.90259

NH3 0.00454 343.15 37.28 58.0785493

C3H6N6 22.295 343.15 168.9[18] 1292174.39

29

REFERENCES

[1] EUROTECNICA Contractors and Engineer,

http://www.eurotecnica.it/index.php/en/technologies/melamine

[2] 2-D Structure: http://www.biotek.com/resources/articles/competitive-elisa-

melamine.html

3-D Structure

http://culturesciences.chimie.ens.fr/content/la-melamine-structure-toxicite-et-

fraude-856

[3] [4][13] Open Chemistry Database

http://pubchem.ncbi.nlm.nih.gov/compound/melamine

[5] Chemical Economics Handbook

https://www.ihs.com/products/melamine-chemical-economics-handbook.html

[6] IndiaMart.com

http://dir.indiamart.com/impcat/melamine-powder.html?biz=10

[7] Blog de ingenieríaquímica

http://iqriosity.blogspot.in/2014/05/melamine-manufacturing-

process.html

[8][9][10][11][12] Southern Chemical Corporation

http://www.southernchemical.com/wp/products/melamine/melamine-

manufacturing-process

[14] United States Patent Office- Lun Lee Yuan, Wayne, N.J. and George

Kurose, Norwalk, Conn., assignors to American Cyanamid Company. Patent

filed Oct. 5, 1964, Sr.no. 401 5552.

30

[15] United States Patent Office- Jacob T.C. Kerkels, Sittard, Netherlands,

assignor to Stamicarbon N.V., Heerlen, Netherlands. Patent Filed Nov. 17,

1969, Ser. No. 87224

[16] Van Ness Smith & 7th Edition

[17] http://webbook.nist.gov/cgi/cbook.cgi?ID=C108781&Mask=2(cp value of urea)

[18] LIU Peng1, XIONG Wei1 HU Shan, Zhou1 LI Xi1 TAN Zhi, Cheng (Enthalpy of

Formation, Heat Capacity and Entropy of Melamine): For thermodynamic values

[19] Data Sheet: Melamine

http://www.sciencelab.com/msds.php?msdsId=9924600