National Fertilizer Limited Bathinda

1. GAURAV SONI
Chemical engineering department
IIT Roorkee
National
Fertilizers
Limited
Bathinda

2. AMMONIA
PLANT
UREA
PLANT
STEAM
GENRATION
PLANT
BAGGING
PLANT
Four
Sections

3. Desulphurization
section
Reforming
section
Shift section
Carbon dioxide
removal section
Methanation
section
Ammonia
synthesis section
1 2
3 4
5 6
Ammonia
Plant
(900MT/Day)

4. Desulphurization Section
General Information:
• Natural gas contains up to 10
vol ppm sulphur compounds.
• Gas contains both H₂S and
organic sulphur compounds.
• Desulphurization takes place
in two stages.
1. Hydrogenation
2. H₂S absorption
TK- 250
HTZ – 5 catalyst

5. TK- 250
HTZ – 51 catalyst
Hydrogenation
In case if Natural gas containing CO and
CO₂ is fed to the hydrogenator, the
following reactons will take place
CO₂ + H₂ ↔ CO + H₂O
CO₂ + H₂ ↔ COS + H₂O
(400˚C)
(38 Kg/cm2)
35˚C
(39 Kg/cm2)
(395˚C)
(351˚C)
C2H6- 9
C3H8- 3
C4H10- 2
C6H12- 0.25
CH4 – 84.50
N2 – 1.25
TK-250 must not get into
contact with HC’s without
presence of hydrogen.
This will increase sulphur
slip to reforming section.
CoMo or
NiMo based
catalyst.
(Pyrophoric)

6. TK- 250
HTZ – 51 catalyst
H₂S absorption
• The hydrogenated natural gas is fed to
the Sulphur Absorbers ( R 202 A/B).
• Zinc oxide catalyst is in the form of 4
mm extrudates.
• Operating temperature is approx.
395˚C.
ZnO + H₂S ↔ ZnS + H₂O
ZnO + COS ↔ ZnS + CO₂
• Sulphur content in the natural gas =
less than 0.1 ppm by weight
(351˚C)
Ar – 0.02, CH4 – 79.68, CO – 2 ppm,
CO2 – 0.24, H2 – 4.09, N2 – 2.54,
C2H6 – 6.48, C3H8 – 2.63, C4H10 –
1.88, C6H12 - 0.24
C2H6- 9
C3H8- 3
C4H10- 2
C6H12- 0.25
CH4 – 84.50
N2 – 1.25
TK- 250
(400˚C)
(38 Kg/cm2)
35˚C
(39 Kg/cm2)
(395˚C)
Does not react with Oxygen and
hydrogen, Not pyrophoric. Steam
operation should not be carried out.
Operating temp – 350-400’C
ZnO = More than 95%
Al2O3 = Less than 5%
Shape- Cylindrical Extrudates

7. Reforming Section
General Information:
Desulphurized gas is converted into synthesis
gas by catalytic reforming of the hydrocarbon
mixture with steam and the addition of air.
CnH2n+2 + 2H₂O ↔ Cn-1H2n + CO₂ + 3H₂ - heat
CH₄ + 2H₂O ↔ CO₂ + 4H₂ - heat
CO₂ + H₂ ↔ CO + H₂O - heat
Reactions take place in two steps
1. Primary reforming
2. Secondary reforming

8. Primary Reforming
• Heat is transferred by radiation from a number of
wall burners to the catalyst tubes.
• Hydrocarbon in the feed converted to CO₂ and
H₂ with 13.3 mole% of methane(dry)
• Reformer tubes is loaded with catalyst RK-211
(prereduced) followed by a layer of RK-201,
while the bottom part of the reformer tubes is
loaded with catalyst R-67_7H.
520˚C
791˚C
Operating parameter
1. Inlet temperature : 520 ºC
2. Exit temperature : 785 - 795 ºC
3. Pressure: 34 - 31 kg/cm2 g
4. Steam/carbon ratio: 3.0 mole/mole
RK-211
RK-201
R-67_7H
Contents
Nickel(Ni)
Calcium Oxide(CaO)
Potassium oxide(K2O)
Aluminum Oxide(Al2O3 )
Nickel Monoxide(NiO)
Calcium Oxide(CaO
Potassium oxide(K2O)
Aluminum Oxide(Al2O3 )
Nickel Monoxide(NiO)
Calcium Oxide(CaO
Aluminum Oxide(Al2O3 ) Ni-S + H2O = NiO + H2S
C+O2 = CO2

9. Composition : (Mole %)
(At Inlet of Catalyst
Tubes)
Ar – 0.02
CH4 – 79.68
CO – 2 ppm
CO2 – 0.24
H2 – 4.09
N2 – 2.54
C2H6 – 6.48
C3H8 – 2.63
C4H10 – 1.88
C6H12 - 0.24
Composition: (Mole %)
(At Outlet of Catalyst
Tubes)
Ar – 47 ppm
CH4 – 12.86
CO – 9.5
CO2 – 10.70
H2 – 66.20
N2 – 0.74
Higher HC - Neglegible
Primary Reformer Inlet & Outlet

11. Secondary Reforming
520˚C
791˚C
• The process gas is mixed with air.
• Partial combustion takes place in the top
of R 203.
• Methane concentration is 0.60
mole%(dry).
• Outlet gas contains about 13.05mole%
(dry) CO and 7.24mole% (dry) CO₂.
• Loaded with RKS-2-7H, and RKS-2 catalyst.
H2+O2=H2O
CH4+O2= CO2+2H2O
958˚C
(550 ˚C)
(1100-1200˚C )
Operating Pressure: 30 kg/cm2 g
H2/N2 Ratio: 3.0
Ar – 0.27
CH4 – 0.60
CO – 13.37
CO2 – 7.65
H2 – 55.61
N2 – 22.47
Ar – 47 ppm
CH4 – 12.86
CO – 9.5
CO2 – 10.70
H2 – 66.20
N2 – 0.74
NiO = 8 – 10%
Al2O3 = 87 – 90 %
Cao = < 0.05
RKS-2
RKS-2-7H
RKS-2

12. CO Shift Section
General Information:
CO + H2O ↔ H2 + CO2 + heat
• Shift reaction takes place in the two CO
converters:
• HT CO-Converter( R 204)
• LT CO- converter (R 205) with process gas
cooling after each converter

13. HT CO-Converter(R 204)
• Contains SK-201-2 catalyst installed.
• The catalyst is Cu promoted
iron/chromium based, in the form of
pellets.
• Can operate continuously in the range of
320-480˚C.
• Chlorine and inorganic salts are poisons to
the catalyst. (Below 1ppm)
360˚C
432˚C
340˚C
205˚C
(29.6 kg/cm2)
(SK-201-2)
1. Mechanical stability
2. Low Steam to Carbon ratio
3. Low byproduct formation
Fe2O3 - 85- 95 %
Cr2O3 - 7-9 %
CuO - 1-2%
Al2O3 - 1.0%
Ar – 0.27, CH4 – 0.60,
CO – 13.37, CO2 – 7.65,
H2 – 55.61, N2 – 22.47
Ar – 0.24
CH4 – 0.55
CO – 3.22
CO2 – 15.94
H2 – 59.59
N2 – 20.48

14. LT CO-Converter(R 205)
360˚C
432˚C
340˚C
205˚C
(29.6 kg/cm2)
(28.6 kg/cm2)
227˚C 160˚C
• Loaded with a top layer of LSK and a bottom
layer of LK-821-2.
• Can be operated within a temperature range
of 170-250˚C.
• The activity of the catalyst increases with
increasing temperature, but the life of the
catalyst shortened
• LSK is installed to catch possible chlorine in
the gas.
• Amount of CO (3.22 – 0.30), CO2 (15.94 –
17.72)
205˚C
(LSK)
(LK-821-2)
(SK-201-2)
Ar – 0.24
CH4 – 0.53
CO – 0.30
CO2 – 18.32
H2 – 60.73
N2 – 19.88
Ar – 0.24
CH4 – 0.55
CO – 3.22
CO2 – 15.94
H2 – 59.59
N2 – 20.48
Ar – 0.27, CH4 – 0.60,
CO – 13.37, CO2 – 7.65,
H2 – 55.61, N2 – 22.47
• Consist of oxides of copper,
zinc, chromium or
aluminium
• Temperature range - 170-
250˚C.
• Top layer catches possible
chlorine in the gas and also
preventsliqvid droplets from
reaching bottom
layer.(Disintegration may
takes place)

15. CO2 Removal Section
General Information:
• Based on two stage activated
MDEA process
• The solvent used for CO2
absorption is aMDEA(40%)
• Consists of a two stage CO2
absorber, a CO2 stripper and
two flesh vessels.
• Outlet gas from CO converter
contain 17.7 mole% CO2.
R3N + CO2 + H2O ↔ R3NH+ + HCO3
-
2R2NH + CO2 ↔ R2NH2
+ + R2N-COO-

16. (65˚C)
Process
Condensate
Process gas
(F-304 CO2 Stripper) (50˚C)
(76˚C)
IMTP-50
IMTP-25
Purified gas
0.59 Kg/cm2 5.1 Kg/cm2
Ar- 0.24
CH4- 0.53
CO- 0.30
CO2- 17.7
H2- 80.75
N2- 19.89
CH4, CO, CO2, H2, N2
Ar- 0.29
CH4- 0.65
CO- 0.36
CO2- 0.05
H2- 74.29
N2- 24.36
(72˚C)
(82˚C)
(45˚C)
99.88% CO2
(50˚C)
0.35 Kg/cm2
IMTP-50
(95˚C)
Process gas
(160˚C)
27.8 Kg/cm2
(131˚C)
(65˚C)
(65˚C)
27 Kg/cm2
26.7 Kg/cm2
(60˚C)
(50˚C)

17. Methanation Section
General Information:
• Methanation, a process in which the residual
corbon oxides are converted into methane.
• Methane acts as an inert in the ammonia
synthesis section
CO + 3H2 ↔ CH4 + H2O + heat
CO2 + 4H2 ↔ CH4 + 2H2O + heat
• Low temperature, high pressure and a low
water vapour content favours the
methanation equilibrium.
• Methanator (R 301) has one catalyst bed
loaded with PK-7R catalyst

18. (300˚C)
(322˚C)
PK-7R
(90˚C)
(285˚C)
(100˚C)
26.7 Kg/cm2
(60˚C)
• Temperature range of
methanator- (280˚C - 420
˚C )
• Catalyst sensitive to sulphur,
chlorine compounds.
• PK-7R is Nikel based
catalyst.
Deactivation of catalyst can be
caused by:
• Thermal ageing
• Gradual poisoning by
impurities in the feed gas
such as potassium, sulphur
or arsenic.
• CO & CO2 conc. Should be
below 1 mole% to minimize
temperature increment.
• Now pressure of gas
is increased from 25
to 187 Kg/cm2 in
various stages with
Synthesis gas
compressor, gas
booster.
• At every stage
temperature gets
increases, to
maintain low
temperature Syngas
compressor chillers
are installed in
between.
25 Kg/cm2
Ar- 0.29, CH4- 1.08,
H2- 73.95, N2- 24.88
Ar- 0.29, CH4- 0.65,
CO2-0.05,CO-0.36,
H2- 74.29,N2- 24.36

19. Ammonia Synthesis Section
General Information
• In ammonia converter R-501:
3H2 + N2 = 2NH3 + heat
• High pressure and low
temperature favours
equilibrium conc. of ammonia.
• About 20% of N2 and H2 is
converted to ammonia.
• Unconverted remainder is
recycled back.
187 Kg/cm2
(130˚C)
(354˚C)
183.6 Kg/cm2
• Ammonia Synthesis catalyst -
KM1/KM1R
• High concentration of oxygen
compounds at the converter
inlet, even for short periods of
time, should be
avoided.(permanent deactivation
takesplace).
Features of the catalyst
1. Stable pressure drop
2. Long operating life
3. High resistance to poison
• Normal operating temperature for
First bed : 370-510
Second bed: 425-480
Third bed: 420-460
KM1/KM1R
Non pyrophoric upto 90-100’C
Temperature range – 530-550’C
Features of the catalyst :
1.Stable pressure drop
2. Long operating life
3.High resistance to poison
Iron based catalyst with some
non reducible oxides.

20. (130˚C)
187 Kg/cm2
(354˚C)
(270˚C)
(180˚C)
(10˚C)
(10˚C)
(10˚C)
178.9 Kg/cm2
27 Kg/cm2
25 Kg/cm2
(11˚C)
(12˚C)
Ar- 2.49
CH4- 8.38
H2- 82.48
N2- 20.82
NH3- 5.82
Ar- 3.16
CH4- 16.12
H2- 38.06
N2- 15.76
NH3- 26.88
Ar- 0.01
CH4- 0.16
H2- 0.06
N2- 0.04
NH3- 99.73
Ar- 2.11
CH4- 7.14
H2- 52.84
N2- 17.61
NH3- 20.30
Ar- 1.82, CH4- 6.18, H2-
65.95, N2- 21.99,
NH3- 4.06

21. (10˚C)
178.9 Kg/cm2
27 Kg/cm2
(11˚C)
Ar- 3.16
CH4- 16.12
H2- 38.06
N2- 15.76
NH3- 26.88
Ar- 2.49
CH4- 8.38
H2- 82.48
N2- 20.82
NH3- 5.82
(61˚C)
20 Kg/cm2
Ar- 64ppm
CH4- 0.03
H2- 0.06
N2- 0.02
NH3- 99.88
Ar- 2.71
CH4- 9.46
H2- 65.73
N2- 22.08
NH3- 0.01
(45˚C)
25 Kg/cm2
(248˚C)
Ammonia Recovery

22. Synthesis section
Decomposition
section
Recovery section
Crystallizations and
Priling Sections
1 2
3 4
Urea
Plant
(1550MT/Day)
MITSUI-TOATSU Total Recycle ‘C’ Improved Process

23. • Urea is produced by the highly
exothermic reaction of Ammonia and
carbon dioxide to form ammonium
Carbamate with slightly endothermic
dehydration of ammonium Carbamate
to form urea.
The reactor temperature is controlled by the
combination of the following factors:
1. Excess ammonia to the reactor
2. Recycle solution rate to the reactor
3. Pre-heat temperature of liquid ammonia
to the reactor.
Synthesis Section

24. Decomposition Section
1. Here Carbamate is decomposed to
ammonia and carbon dioxide gasses.
NH2COONH4 = CO2 + 2NH3
2. Decomposition is usually achieved at
temperature of 1200C to 165oC
Decreasing pressure favors
decomposition as dose increasing
temperature.
3. During decomposition, hydrolysis of
urea becomes an important factor.
Hydrolysis proceeds as per the
following reaction:
NH2 CONH2 +H2O = CO2 + 2NH3
At low partial pressure of ammonia and temp. Above 900C
Urea converts to form ammonia and biurate as in the overall reaction
below:
2 NH2CO NH2 = NH2 CONHCO NH2 +NH3

25. Recovery Section
1. The unreacted ammonia and CO2 can
not be compressed in practical instead
of this we do
1. Separate and recycle as gasses.
2. Recycle in a solution or slurry
form.
NFL Bathinda uses second one.
1. The mixture of ammonia CO2 gasses
from the decomposers are absorbed in
water and urea solution in the
respective absorbers and recycle back
to the urea synthesis reactor.
2. The excess ammonia is purified in
high-pressure absorber and recycled
separately to the reactor through
ammonia condensers

26. Crystallization Section
1. The urea solution leaving the
Carbamate decomposes is vacuum
crystallized and urea crystals are
separated by centrifuge.
2. Crystals formed in the vacuum
crystallizer are centrifuged and then
dried to less than 0.3% moisture by hot
air.
3. The biurate is converted back to urea in
presence of excess ammonia.
NH2 CONHCONH2 +NH3 = 2NH2CONH2
4. Dry crystals are conveyed to the top of
prilling tower passing through
Fluidizing dryer

27. Prilling Section
• Dry crystals of urea collected in
the air dryer in which it is dried by
passing dry air from F.D. fan.
• Attain a temperature less than
melting point of urea i.e. 1200C.
• Dry crystals are conveyed to the
top of prilling tower passing
through pneumatic duct and send
to the melter via cyclone and
screw conveyor to melter.
• In melter dry urea crystals are
melted by using 7K steam and
finally reaches to the Head tank .
In melter temperature of molten
urea control up to 1370C to avoid
the biuret formation.

28. Prilling Section
• Molten urea solution comes from
head tank to acoustic granulator
and then sprayed in the form of
prills form a rising column of
prilling tower.
• These prills get cooled down by
F.D. fan air which take suction from
atmosphere and send it through
continuous fluidized dryer.
• After cooling of prills not less than
450C, it is conveyed to bagging
plant via passing through trommel
and belts and finally stored in the
silos.

29. Thank you 