Ammonia Production

1. National Fertilizers Ltd.
Bathinda
AJAY NAGAR
10112001

2. Sections
▶ Ammonia Plant
▶ Urea Plant
▶ Steam Generation Plant
▶ Bagging Plant

3. Ammonia Plant
▶ Desulphurization Section
▶ Reforming Section
▶ Shift Section
▶ Carbon Dioxide Removal Section
▶ Methanation Section
▶ Ammonia Synthesis Section

4. HYDROGENATOR:
• Reactions involved in Hydrogenator are:
2 2
R1SSR2 + 3H2 → R1H + R2H + 2H2S
R1SR2 + 2H2 → R1H + R2H + H2S
COS + H2 → CO + H2S
Desulphurization Section
Natural Gas Feed
Recycle
R
H
Sy
H
dr
+
og
H
en→ RH + H S
Feed Gas Preheater
• If some content of CO2 is also exist in Natural Gas feed then:
CO₂ + H₂ ↔ CO + H₂O
CO₂ + H₂S ↔ COS + H₂O
• CoMo or NiMo based catalyst is used in HydroH
gy
ed
nr
ao
tg
oe
rn
.ator
Sulphur
Absorber
No. 1 Sulphur
Absorber
No. 2
400oC
38 Kg/cm2
395oC
39551o
C
Natural Gas With
Recycle Hydrogen

5. Desulphurization Section
H₂SABSORBER:
• The Hydrogenated Natural Gas is fed to the SulphurAbsorbers.
• Zinc oxide catalyst is in the form of 4 mm cylindrical extrudates.
• Operating temperature is approx.
395˚C. ZnO + H₂S ↔ ZnS + H₂O
ZnO + COS ↔ ZnS + CO₂
• Sulphur content in the natural gas is less than 0.1 ppm by weight.

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

7. Primary Reformer
Desulphurized Gas
Preheater
Primary
Secondary
Reformer
ProcessAir
785-795oC
520oC
34 - 31 kg/cm2 g
ide, NiO (17)
4 B
a
lance)
S
t
%
e
a
m
) Carbon Mole Ratio=3/1
Process SteamTubes)
CH4 – 79.68
CO2 – 0.24
C
H
o
m
2p–o4s.i0t9ionof catalyst (% w/w)
2.C2HC6al–ci6u.m48Oxide,CaO (7)
3H
Po
8t–
as
2
s.i6
u
3
m oxide, K2O (4)
.
C
.
C4
H
A
1
l
u
0
m
–
i
1
n
.
u
8
m
8Oxide,Al2O3 (
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
▶ As we have seen that we areC
go
em
ttp
io
ns
gi
t
i
ao
n
ro:
u(
M
ndo
l
e
12.86 mole % of methane an(
dA
wtI
en
l
de
t
oo
nf
’C
ta
wt
a
al
y
ns
tt
it to be exist in stream just be
A
cr
a–
us
0e
.02
it will be
acting as inert in whole furthC
er
Op
–
ro
2c
pe
ps
m
ses.
So we have to remove it.
f.
N
▶ `For removing this access o
1 m
2 N
–
ei
t2
c
h
.k
5
a
e
4
n
l e
Mw
on
e
ox
use Secondary Refo
R
re
m
foe
rr
m
.er 3
Product
Stream
of
Primary
Reformer
Process Gas

8. Secondary Reformer
• The process gas is mixed with air with keeping the
ratio of H2/N2 Ratio: 3.0.
• Partial combustion takes place in the top of reactor.
• Methane concentration is 0.60 mole%.
• Outlet gas contains about 13.05mole% CO and
7.24mole% CO₂ that are removed further because
catalyst may get poisioned.
550oC
791oC
1100-1200oC
958oC
30 kg/cm2 g
composition(%mole):
NiO = 8 – 10%
Al2O3 = 87 – 90 %
Cao = < 0.05 %
Gas inlet
composition (mole%)
Ar – 47 ppm
CH4 – 12.86
CO – 9.5
CO2 – 10.70
H2 – 66.20
N2 – 0.74
Catalyst
Gas outlet
composition (mole%)
Ar – 0.27
CH4 – 0.60
CO – 13.37
CO2 – 7.65
H2 – 55.61
N2 – 22.47

9. CO Shift Section
• Exothermic reaction which occurs in this section is:
CO + H2O ↔ H2 + CO2 + heat
• Shift reaction takes place in the two CO converters:
1. HT CO-Converter.
2. LT CO- converter with process gas cooling after each converter.

10. HT/LT CO Convertors
Waste heat
boiler
BFW Preheater 1 BFW Preheater 2
360oC
29.6kg/cm2
432oC
205oC
227oC 160oC
Fe2O3 - 85-C9o5nv%ertor
Cr2O3 - 7-9 %
CuO - 1-2%
Al2O3 - 1.0%
250oC.
Composition (mole%)
oP
fri
o
n
cl
ee
ss
t g
sa
tr
se
fa
ro
m
mo
R
fef
H
or
T
mer Section
CO Converter is:
Ar – 0.27, CH4 – 0.60,
CO C
–a
1t3
a.l3
y7
st
,’C
s c
O
o
2
m
–
position
7.65(,m
H
o
2
le
–
%
5
)5w
.6h
1i,cN
h 2
is–
22.4a
7
vailable in pell
H
eT
t f
C
oO
rm.
205oC
Composition (m2
o8
.
l6
ek
%g
/
c
)m
2
of outlet stream of HT
CO Converter is:
Ar – 0.24, CH4 – 0.55
CO – 3.22, CO2 –
M1
et5
h.a
9
n4
ator trim
he
H
at
2
er
– 59.59, N2 – 20.48
Catalyst consist the
oxides of Cu, Cr and
L
A
T
l,C
W
O hich
Co
is
m
m
po
os
st
ition (mole%)
C
aco
tn
iv
ve
er
t
io
nr
b
o
e
ft
o
w
u
e
t
l
e
e
n
t1
s
t
7
r
0
e
a
-m of LT
CO Converter is:
Ar – 0.24, CH4 – 0.53
CO – 0.30, CO2 –
18.32
H2 – 60.73, N2 – 19.88
340oC

11. CO2 Removal Section
• Outlet gas from CO converter contain 18.32 mole% CO2
• 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.
• These are the reactions occurs in CO2 removal section.
3
R3N + CO2 + H2O ↔ R3NH+ + HCO -
+ -
2R2NH + CO2 ↔ R2NH2 + R2N-COO

12. CO2 to Urea
Condensate
Stripper
Reboiler
HE
LS Pump
Cooler
Chiller
LP
Flash
HP
Pump
BFW
Preheater
Semilean Soln
Lean Solution
Process gas
saparator
CO2Absorber
Output after CO2
Absorption
60˚C
26.8 Kg/cm2
Flash gas/ Inerts
Stripper
160˚C
27.8 Kg/cm2
131˚C
65˚C
65˚C
65˚C
27.8 Kg/cm2
50˚C
5.1 Kg/cm2
72˚C
0.59 Kg/cm2
95˚C

13. Methanation Section
▶ Methanation, a process in which the residual Carbon Oxides (CO, CO2) are converted into
METHANE because it acts as inert inAmmonia Synthesis Section.
▶ Reactions involve in Methanator are:
CO + 3H2 ↔ CH4 + H2O + heat
CO2 + 4H2 ↔ CH4 + 2H2O + heat
▶ As we can see these reactions are exothermic so Low temperature, high pressure and a
low water vapour content favours the methanation equilibrium.
▶ After converting all Carbon Oxides into METHANE, product stream is pressurised from
25Kg/cm2 to 187Kg/cm2 by using compressors and gas boosters and for maintaining
temperature, chillers are being used.

14. Gas/Gas
HE
Trim
heater
Process gas for
LT CO Converter
Process gas from
HT CO Converter
Synthesis gas to loop
60˚C
26.8 Kg/cm2
285˚C
300˚C
322˚C
90˚C
25 Kg/cm2
MetN
ha
ic
n
k
a
etlob
rased catalyst
is used here in methanator
which consist around 27%
wt Nickel. (280-420˚C)
Composition(%mole)
Sy
an
tt
ih
ne
le
stis
isG
: as From
C
A
O
r
-R
0
.
e
2
m
9
,
o
C
v
H
a
l
4
S
-
e
0
c
.
t
6
i
5
o
,
n
CO
2
2-0.05,CO-0.36,
H2- 74.29,N2- 24.36
Composition(%mole)
at inlet is:
Ar- 0.29, CH4- 1.08,
H2- 73.95, N2- 24.88

15. reaction.
• There are three beds we use inAmmonia Convertor:
First bed : 370-510 ˚C
Second bed: 425-480 ˚C
Third bed: 420-460 ˚C
Ammonia Synthesis Section
3H2 + N2 = 2NH3 + heat (ΔH = −92.4 kJ/mol)
354˚C
183.6 Kg/cm2
Feed gas inlet
130˚C
187 Kg/cm2
Feed gas inlet Outlet
Feed gas inlet
Fe Oxied (Fe3O4) %wt 93 ±2
2 4 2 2
• High pressure and low temperature favourableC
e
q
a
u
O
i
l
i
,
b
A
r
i
u
lm
O
c
,
o
K
n
d
O
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t
i
,
o
n
S
s
i
O
o
f
,
a
%
m
m
w
o
t
n
i
a
7±2
With the irregularshape beads
• About 20% of N2 and H2 is converted into a
m
w
m
o
i
t
n
h
i
a
t
h
a
e
tg
s
i
i
v
z
e
e
no
o
p
fe1r.a5t-in3gmcmonditions.
• Unconverted remainder is recycled back.
Bulk density 2.8kg/l

16. Startup
Let Down
Gas
Product let
Down tank
Ammonia
Separator
Purge Gas
Makeup Synthesis
Gas
Ammonia
Converter
Cooler
Compressors
10˚C
Chiller
10˚C
27Kg/cm2
10˚C
Synthesis
Hot
CSotmeapmosition(mole%H)eaat
OB
uo
tl
il
e
e
trofAH
mE
moniaExchanger
Converter
354˚CAr2
-7
20
.1̊C
1, CH
14
8-07̊C
.14
H2- 52.84, N2- 17.61
NH3- 20.30
Composition(mole%) of
Purge Gas ofAmmonia
178.9Kg/cm2
Converter
Ar- 2.49, CH4- 8.38
H2- 82.48, N2- 20.82
NH3- 5.82
Composition(mole%) of Let
Down Gas ofAmmonia
Converter
Ar-3.16, CH4-16.12
1
H
1
2
˚C
-38.06, N2-15.76
NH3-26.88
Composition(mole%) of Product
Stream ofAmA
m
m
on
m
ia
on
C
ia
onverter
A1
r-
20̊C
.01, CH4-
(P
0r
.1
o6
duct)
H2
25
-K
0.g
0/6
c,m
N
22- 0.04
NH3- 99.73
Composition(mole%) at
Inlet ofAmmonia
HCeoantvererter
Ar- 1.82, CH4- 6.18,
H2- 65.95,1N302˚-C21.99,
NH3- 4.06187Kg/cm2

17. Ammonia Recovery
Ammonia
Reflux
Distillation
Column
Reboiler
Purge Gas
Absorber
Lean Soln
Cooler
Circulation Pump
Steam
Richlean
Soln
Exchanger
248˚C
178.9Kg/cm2
61˚C
20Kg/cm2
45˚C
25Kg/cm2
Composition(mole%) of
Purge Gas:
Ar- 2.49, CH4- 8.38
H2- 82.48, N2- 201.802˚C
NH3- 5.82
Purge Gas
Composition(mole%) of
Le
L
teD
t o
D
w
on
wG
na
G
s:
as
11˚C
Ar- 3.16, CH4- 16.2172Kg/cm2
H2- 38.06, N2- 15.76
NH3- 26.88
Composition(mole%) of
Fuel Gas:
Ar- 2.71, CH4- 9.46
Fuel Gas H2- 65.73, N2- 22.08
NH3- 0.01
Ammonia
OH Drum
Composition(mole%) of
Product Gas:
AmA
mro
-n
6i4
appm, CH4- 0.03
H2- 0.06, N2- 0.02
NH3- 99.88

18. Conclusion
▶ National Fertilizer Ltd. Bhatinda is producing 99.80% pure Ammonia
by Using Natural Gas with the help of helder tropsch method for
furtherproduction of Urea.

19. “
”
Thank You !!!