Melamine production process

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]

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 385o
C
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 o
C. [14]
INLET (at 385 deg Celsius)
CO2 = 66.885 kmol/h
NH3 = 133.77 kmol/h
OUTLET (at 72 deg Celsius)
CO2 = 66.885 kmol/h
NH3 = 45.41 kmol/h
CO2 = 66.885 kmol/h
NH3 = 133.77 kmol/h
CO2 = 66.885 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
NH3 = 45.41 kmol/h
OUTLET (70 deg Celsius)
CO2 = 0.02 kmol/h
NH3 = 0.00454 kmol/h
CO2 = 0.02 kmol/h
NH3 = 0.00454 kmol/h
CO2 = 66.885 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
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
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
ENERGY BALANCE FOR STRIPPING SECTION:
Inlet Temperature: 393.15 ͦC
Outlet Temperature: 343.15 ͦC
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
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
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
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

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