Sui Generis Magazine volume one Kristen Murillo.pdf
Ammonia-PPT GTEs.pptx
1. IN THE NAME OF ALLAH,THE MOST
BENIFICIENT AND THE MOST MERCIFUL
INTRODUCTION
TO AMMONIA
PLANT
Delivered By:
Amir Shahzad
2. GREEN AMMONIA PRODUCTION
Green ammonia is crucial to tackle
the existential challenges of
producing enough food to feed a
growing global population and
generating CO2-free energy.
Ammonia (NH3), a compound of
nitrogen and oxygen, is mainly used
to manufacture fertilizers. 80% of the
annual global production of over 170
million metric tons is used in this
way. And that should become even
more in the next few years.
4. 4
Ammonia Plant
• The name plate capacity of
ammonia plant was 910 Tons/day.
Licensed and guaranteed by
M.W.KELLOG
• In 1986 PGRU was installed &
Plant’s capacity was increased to
960 Tons/day.
7. 7
Briefs of Plant
Ammonia plant is divided into
following major sections
•Desulphurization
•Gas preparation
•Gas purification
•NH3 synthesis
•NH3 storage
8. CLASSIFICATION OF EQUIPMENTS
• A Pits like 101-A blow down pit.
• B Furnaces , Heaters and their accessories like 103-
B pre heater.
• C Exchangers all types like coolers, chillers
• D Reactors like 103-D secondary reformer
• E Towers like 101-E absorbers
• F Drums and Tanks like 101-F steam drum,1201-F
Ammonia storage Tank
• J pumps and Compressor Like 101-J air comp.
• L Special equipments like 103-L S/Condensor
• U Utility equipments
14. 14
Hydrogenation
Hydrogenation is the conversion of
organic sulphur compound into
inorganic sulphur compound.
For example
RSH + H2 = RH + H2S Exothermic
R2S + 2H2 = 2RH + H2S
15. 15
H2S Removal
• H2S is removed by ZnO bed according
to following reaction
ZnO + H2S = ZnS + H2O
• There are Two vessels for H2S removal
101-D & 102-D
16. 16
• 101-D
• Catalyst Type Mixture of Catalysts (ZnO)
• Volume 22.5 M3 (12 NCT+10.5 Mixture)
• 102-D
• Catalyst Type NCT-305 Chinese made
• Volume 22.5 M3
23. 23
Steam Reforming Reactions
• Very Endothermic
• CH4 + H2O = CO + 3 H2
• CnH2n+2 + nH2O = n CO + (2n+1)H2
• Water gas shift reaction
• CO + H2O = CO2 + H2
• Overall reaction is highly endothermic
24. Primary Reforming Theory Basics
• Steam to Gas Ratio
This is similar to steam to carbon ratio but
is the ratio of the steam rate to the feed
rate. Provided that the feedstock composition
remains constant, then this ratio does give a
true indication of the steam to carbon ratio.
However, if the feedstock composition does
vary, it is possible to operate at too low a
steam to carbon ratio which can lead to
carbon deposition.
25. 25
Reforming
•Both reforming & shift reactions are
reversible.
•Methane conversion is favored by:
•Low Pressure
•High temperature
•High steam carbon ratio
26. Primary Reforming Theory Basics
Reaction Rate
To achieve high reaction rate steam
methane reforming requires
High activity and GSA of Catalyst
High temperature
High Pressure
Equilibrium
To achieve equilibrium
of methane reforming
requires
High Steam to
carbon ratio
High temperature
Low Pressure
33. 33
Reformer Tubes
• Total No of tubes 378
• No of Risers 9
• No of arch burners 200
• Tube length 9571.5 mm
• Tube ID 71.1+-1.25 mm
• Tube wall thickness 18.57 mm
35. 35
I D Fan
• The I D fan provides:
1. Adequate draft for the exit of
flue gases.
2 Maintain negative pressure in the
primary reforming furnace & aux
boiler.
The fan is driven by steam turbine.
36. FLUE GAS CIRCUIT 101-B
Convection Section
101-B
Radiant Section
101-B
Stack
104-B
I.D. Fan
101-BJ
38. 38
Secondary Reformer
•The partially reformed gases enter
the secondary reformer chamber
from the side.
•It then directed downward through
the diffuser ring into the combustion
zone of the reactor.
39. 39
Secondary Reformer
• Air is introduced in secondary reformer.
• The combustion of a part of H2 & CH4 takes place at top
portion.
• Heat of combustion is utilized for further reforming.
• CH4 + H2O = CO +2 H2
• CH4 + O2 = CO + 3H2
• 2H2 + O2 = 2 H2O - 242 kJ / mole
• The gases leaves the secondary reformer at 996 OC.
42. 42
Exit Sec Reformer
• N2 23.39 %
• H2 56.05 %
• CH4 0.24 %
• A 0.28 %
• CO2 8.24 %
• CO 11.80 %
43. 43
101-C & 102-C
• The gases leave the secondary reformer at 996 OC the
enter the HTS converter at 310 oC.
• The difference of heat is utilized by waste heat exchangers
101-C & 102-C for heating the B F water to generate the
steam.
• These 2 exchangers alone are responsible for supplying
about 70 % of heat requirements of steam.
44. Boiler Feed Water in inner tube
Steam exit from outer tube
Bayonet Type Tube
Disc and doughnut Baffle Tubes
Shell Flow Pattern
101-C TUBES CONSTRUCTION
46. 46
HTS
• The purpose of HTS converter is to oxidize CO to
CO2.
• Reaction
CO + H2O = CO2 + H2 - 41.1 KJ / mole
• The CO slippage from HTS should be less than
3.0 %.
• The principle operating variables are steam to gas
ratio & temperature.
• Increasing steam results in an increase to CO
conversion.
47. 47
HTS
• At least 20 % steam must be present in the gas
passing over the catalyst when at a temperature above
180 OC
otherwise
change in structure of the catalyst will results with loss of
physical strength.
48. 48
HTS
• Catalyst Type C12-4
• Catalyst volume 53 M3
• Size Dia 9 * 5 ~ 7 mm
• Shape Tablet
• HTS is supplied in the form of Fe2O3 Hematite
• HTS is reduced to active Fe3O4 Magnetite
• Fe2O3 = 88 % Cr2O3 = 9 % CuO = 2.6 %
49. 49
Exit HTS
• N2 21.01 %
• H2 60.51 %
• CH4 0.23 %
• A 0.27 %
• CO2 16.34 %
• CO 1.64 %
50. 50
LTS
• The purpose of LTS is convert remaining 3.0 % CO to
CO2.
• Catalyst Type ICI 83-3
• Form Pellet
• Size Dia 5.2 mm
length 3.0 mm
• CuO 51 %
• ZnO 31 %
• Al2O3 16 ~19 %
52. 52
Exit LTS
• N2 20.81 %
• H2 60.87 %
• CH4 0.23 %
• A 0.27 %
• CO2 17.61 %
• CO 0.21 %
53. LTSC by product
• CO2+3H2 → CH3OH+H20
• Methanol increase with
• High temperature
• High inlet CO levels
• Low S:C ratio
It consumes Hydrogen thus reduces production.
53
56. T= 78
P= 27.1
CO2 Absorber
101 - E
102 – F
T = 126
P = 27.4
117
-
F
113-C 105-C
From LTS
176
C
149
C
PROCESS FLOW DIAGRAM
57. 107-C
108-JS
108-JT
CO2 Stripper
CO2 Absorber
206 m3
/hr
107-JHT
107-JS
107-JT
848 m3
/hr
T= 78
P= 27.1
101 - E
102 - E
102 – F
T = 126
P = 27.4
117
-
F
118 oC
126 oC
78 oC
113-C 105-C
From LTS
176 C
149 C
PROCESS FLOW DIAGRAM
60. 60
Exit CO2 Absorber
• N2 25.36 %
• H2 73.68 %
• CH4 0.27 %
• A 0.32 %
• CO2 0.12 %
• CO 0.25 %
61. 61
METHANATOR
• The purpose of the methanator is to remove oxides
of carbon as much as possible to avoid
1. Poisoning of synthesis catalyst
2. The deposition of ammonium carbamate in
synthesis compressor internals as well as in syn.
loop as a result of CO2 contact with ammonia.
62. 62
METHANATOR
The methanation reactions are:
• CO2 + 4 H2 = CH4 + 2 H2O -39.43 K cal
• CO + 3 H2 = CH4 + 1 H2O -49.27 K cal
• 74 oC rise in temp for 1 % CO
• 60 oC Rise in temp for 1 % CO2
63. 63
Methanator
• Catalyst Type ICI 11-3
• Form Cylindrical Pellets
• Dia 5.4 mm
• Length 3.6 mm
• Density 1.23 Kg/l
• Catalyst Volume 24 M3
• NiO 35 % wt
• MgO 4 % wt
• Support Balance
• SOR Nov,1993
66. SYNTHESIS GAS COMPRESSOR
•The purpose is to compress
synthesis gas along with recycle
gas to a pressure of 120 ~ 140
kg/cm2.
•This compressor has two casings.
• Driven by two AEG steam turbines
in tandem.
66
71. SYNTHESIS CONVETORS
Ammonia converters has S-200
Topsoe designed basket.
It includes two catalyst beds.
One inter bed exchanger.
The flow of gas through these
catalyst beds is radial.
71
72. S-200 CONVERTER BASKET
1
• First Catalyst Bed
2
• Interbed Heat Exchanger
3
• Second catalyst Bed
4
• Centre Screen
5
• Heat Exchanger Section
MAIN PARTS
Manufacturing of new S-200 Basket
73. SECTION DRAWING
TOP BOTTOM
Pressure
Shell
Basket Shell
First Catalyst
Bed
Second Catalyst
Bed
Heat Exchanger
Section
Pressure Shell
Top Cover
Interbed Heat
Exchanger
Gas Flow
Pipe
Centre Screens
74. Synthesis catalyst
• Catalyst Type Topsoe KMI / KMIR
• Magnetite Fe3O4
• Catalyst volume 9.3 M3 KMIR
23.40 M3 KMI.
• SOR Dec 1993
• About 4 M3 of catalyst has been
escaped from 105-DB.
74
75. SYNTHESIS CONVERTORS
• The purpose of ammonia synthesis converters is to
produce ammonia.
• The feed gas containing 2 % of NH3
• Feed gas enters at
• a temperature of 144 0C ~ 170 OC
• a pressure of 120 ~ 140 kg/cm2.
• The converters reaction is:
N2 + 3H2 = 2NH3 + heat
• The % age conversion of NH3 is 12 ~ 14 %
75
76. 1st
Catalyst Bed
2nd
Catalyst Bed
1ST
Bed O/L Heat
Exchanger
Lower Bed Heat
Exchanger
ReactorO/L
PFL NH3 Reactor Flow Path &
Temperature Control
Cold Shot
Main I/L
Quench
80. PIC-121 VENT
VALVE
25.6Kg/cm2,
38C
180C, 70Kg/cm2
115C
41C
105-F
104-F
8 C
147-C
FIC-112
FIC-113
124-C
120-C
118-C 117-C
119-C
KICKBACK
116Kg/cm2
111C
43 C
HCV
50 C
SYN.GAS LOOP
41C
SP5
SP-4
1.5C
-9C
-23 C
FROM 121-C
120-C
121-C
144-C
106-F
105-D
287-C
123-C
TO RECYCLE WHEEL
OF 103-J
108F
107-F
To 112-F
PRODUCTION
-23C
NH3
43C
FIC-111
136-C
116-C
129-C
CHILLER
COOLER
EXCHANGER
103-J
1ST
CASE
2ND
CASE
LC-117
LC-120
81. Factors Effecting Ammonia
Synthesis Reaction
• Temperature
• Pressure
• Inert Level
• Ammonia at Inlet of Reactor
• RATIO H2/N2
• Flow Pattern / Space velocity
82. Effect of Temperature on Reaction.
There are two opposing considerations in this synthesis: the position of the
equilibrium and the rate of reaction. At room temperature, the reaction is
slow and the obvious solution is to raise the temperature. This may increase
the rate of the reaction but, since the reaction is exothermic, it also has the
effect, according to Le Chatelier's Principle. The rate of reaction is related to
the operating temperature as:
So at high temperature, the reaction rate of ammonia synthesis will be high
whilst at low temperatures, the reaction rate will be lower.
83. Effect of Pressure
Pressure is the oblivious choice to favor the forward reaction because there
are 4 four moles of reactant for every 2 mole of product. Pressure used
around (120-200 atm) alters the equilibrium concentration to give a
profitable yield.
Economically though pressure is an expensive commodity. Pipes & reaction
vessels need to be strengthened , valves to be more rigorous & there are
safety considerations of working at 200 atm. In addition running pumps &
compressor takes considerable energy.
84. Inert Level
A continuous bleed off inert gas will be maintained from syngas loop to
control the concentration of methane & argon at ammonia converter inlet,
otherwise these inerts will build up in synthesis loop causing
Higher synthesis loop pressure
Lower conversion, hence reduced production.
85. Ammonia Concentration at Reactor Inlet.
As the concentration of ammonia increases, tendency of forward reaction
ceases. If concentration increases above the equilibrium concentration
then reaction tends to move in the reverse direction. As the reverse
reaction is endothermic, the heat will be consumed & bed temperature will
drop quickly & with a drastic increase in loop pressure.. This in turn will
decrease net conversion. The after effects are
Catalyst temperature will decrease.
Synthesis loop pressure will increase.
Back Pressure will increase.
86. Catalyst.
A typical composition of an industrial ammonia-synthesis catalyst
Fe2O3 1.1 - 1.7
FeO 5.4 – 10.2
Fe 89 - 93
CaO 0.1 – 0.2
SiO2 0.1 – 0.7
MgO 0.3 - 0.6
Al2O3 1.5 – 2.1
K2O 0.2 – 0.5
Porosity 40-50
Poisons:
O2 , S , As , P , Cl2 etc.
CaO , SiO2 , MgO act as
structural promoter
Use of Fe represents a compromise of
(i) Surface nitride formation
(ii) Permit rapid desorption of NH3
87. PGRU
• I is hydrogen recovery unit. 50 ton ammonia is
obtained from this hydrogen. About 8% inerts
are continuously bleeding from syn. loop to
keep pressure in control.
PGRU is mainly classified in two portions
• Pretreatment (NH3 & H2O removal)
• Cold box (Separation of H2 from inerts like
CH4,Ar.,& N2 )
• Hydrogen = 5941NM3/hr
• NH3 =253NM3/hr
• FUEL =3054NM3/hr
89. 89
REFRIGERATION COMPRESSOR
• The purpose of refrigeration compressor is to compress
the ammonia vapor to such a high pressure where
ammonia vapors are condensed by giving heat to
cooling water in exchangers.
• The liquid ammonia formed is returned to refrigeration
section.
• Non condensable are sent to fuel system.
90. 90
Refrigeration circuit
HP Case LP Case 105-JAT
105-J
Ammonia Refrigerant Compressor
134-C 127-CA 127-CB
109-F
126-C
LCV-128
110-F 111-F 112-F
PIC-130
117-C
129-C
128-C
Pic-129
LCV-129
FICa-120
FICa-119
118-C
TO 110-J/JS
LCV-132
STORAGE
FICV-118
FROM 107-F
FR
128
LRa
135
LC
135
119-C
FICa
118
91. 91
ENERGY CONSUMPTION
• Design 9.42 G cal / tons of Ammonia
based on 8303 Kcal/NM3 NG LHV
• Actual 9.617 G cal / tons of Ammonia
based on 7843 Kcal /NM3 NG LHV
94. Major Emergencies
• Power Failure
• Loss of Demin Water/BFW pumps failure
• Steam Failure
• Cooling Water Failure
• ID Fan tripping
• Natural gas low pressure
• Instrument air Failure
• Semi lean/Lean pumps failure
• Air Compressor Failure
• Syn machine tripping
• Refrigeration machine tripping
