SlideShare ist ein Scribd-Unternehmen logo
1 von 33
Downloaden Sie, um offline zu lesen
Ammonia Plant - Methanation
Operations
By:
Gerard B. Hawkins
Managing Director, CEO
Methanation
• Introduction and Theoretical Aspects
• Catalyst Reduction and Start-up
• Normal Operation and
Troubleshooting
• Shutdown and Catalyst Discharge
• Nickel Carbonyl Hazard
• Modern Methanation Catalyst
Requirements
Introduction
 Carbon oxides are poisons for
ammonia synthesis catalyst
 Methanation is the final stage
of purification of synthesis gas
after CO2 removal to reduce
carbon oxides to trace levels
 Uses nickel-based catalyst
Methanation Reactions & Operating
Conditions
 Reactions are highly exothermic
• +74oC (133oF) for every 1% CO converted
• +60oC (108oF) for every 1% CO2 converted
 Typical inlet temperatures
• 270-290oC (520-555oF)
 Typical inlet carbon dioxide
• 0.1 - 1.0 vol%
 Typical carbon oxide slip
• <5 ppmv
CO + 3H2 CH4 + H2O ∆H= -206 kJ/mol
CO2 + 4H2 CH4 + 2H2O ∆H = -165 kJ/mol
Mechanism of Reaction
 Equilibrium concentrations of carbon
oxides 10ppm
 Governed by kinetics
 CO inhibits methanation of CO2
 Two stage reaction:
CO2 reverse -shifts to CO
CO2 + H2 CO + H2O
CO methanates
CO + 3H2 CH4 + H2O
 Intrinsic reaction rates very high
(diffusion limited at higher
temperature)
Typical Flowsheet
Gas from
CO2 Removal
290oC
(554oF)
Process gas to
Ammonia Loop
318oC
(604oF)
Inlet Composition
(vol % dry)
CO2
CO
H2
CH4
N2+A
0.3
0.1
74.7
0.3
24.6
Outlet Composition
(vol % dry)
CO2
CO
H2
CH4
N2+A
<5ppm
74.2
0.8
25.0
Methanator
METHANATOR
CATALYST
VSG-N101
Medium bauxalite
(40mm x 60mm)
Flat
Mesh
75 mm layer small bauxalite
150 mm layer large bauxalite
(60mm x 90mm)
large bauxalite
(60mm x 90mm)
25 mm layer small bauxalite
(25mm x 40mm)
Catalyst Composition
 Iron originally studied
 Ruthenium good at low temperature (“ultra -
methanation”)
 Nickel conventionally used
 Support matrix with 20-40% nickel
 Promoters to reduce sintering
 Small pellets (5mm x 3mm)
 Low temperature operation
 210-230oC (410-445oF)
 Therefore low COx slip, < 5 ppm
 Long lifetimes proven in service
 VSG-N101 and VSG-N102 (Both available as Pre-reduced)
Methanation Catalyst SV & Inlet
Temperature
SV (Hr )-1
220 240 260 280 300 320 340 360
2,000
4,000
6,000
8,000
10,000
Inlet Temperature ( C)
VSG-N101
VSG-N102
Competitor
o
Methanation Temperature Profile
240
245
250
255
260
265
2 2.5 3 3.5 4 4.5 5 5.5 6
Bed depth (m)
Temperature(DegC)1000 te/day Ammonia Plant in PR China
VULCAN VSG-N101-Series Catalyst
Catalyst Reduction
 If catalyst supplied in the oxidised form must be
reduced in the reactor to the active nickel form
 NiO + H2 Ni + H2O ∆H = + 3 KJ/mol
 NiO + CO Ni + CO2 ∆H = - 30KJ/mol
 Reduction process gives little temperature rise
 BUT - metallic nickel will lead to methanation
during reduction
 THEREFORE - reduction gas should not contain
carbon dioxide (<1%)
 Need to heat catalyst to 400-450oC (750-840oF)
for maximum activity
Reduction Procedure
 Purge methanator free of air with N2
 Heat catalyst to 200oC (390oF) in process gas, N2 or
NG
– do not use NG at temperatures above 200oC (390oF) due
to possible methane cracking occurring
 Reduction starts around 200-250oC (390-480oF)
– temperature will rise
– limit carbon oxides in feed to <1%
– control inlet temperature
Reduction Procedure (con’t)
 Increase inlet temperature to 325-350oC (620-
660oF)
– 25oC (45oF) per hour
– maintain until bed exit temperature equals
maximum in bed
– takes about 6 hours
 Increase catalyst temperature to 400-450oC
(750-840oF) for a few hours
– max temperature 450oC (840oF)
– may need controlled bypass of LTS to increase
CO content of inlet
 Decrease bed inlet temperature to design,
increase plant rates
Methanation Catalyst Reduction
400
300
200
100
0 10 20 0 10 20
10
20
30
40
50
60
70
Begin End
Exit
Inlet
CO
CO
Time (hr)
TemperatureC(F)
Time (hr)
ExitCOandCO2(ppm)
(212)
(392)
(572)
(752)
Partial by-pass of
LTS
oo
2
Methanation Catalyst Reduction
Depth m (ft)
Inlet Exit
Flow 70% Design
Inlet CO 0.09%
Inlet CO2 0.11%
Partial LTS Slip
(Inlet CO 0.35%)
* On line
TemperatureC(F)
1 2 3
(3) (6) (9)
250
(482)
300
(572)
350
(662)
2
3.5
5
7 *
24
Time (hr)
oo
Pre-reduced Methanation Catalyst
 Catalyst first reduced, then partially stabilised
– Faster plant start-up
– Higher catalyst activity
 Reduction taken place under controlled
conditions
– Higher Ni surface area
 Lower inlet temperatures possible.
– Minimum inlet temperature 170oC (338oF)
 Catalyst is ready to go
 Do not need to load full charge - only top
portion needs to be pre reduced
Inlet Temperature
 Usually controlled by inlet/outlet gas
heat exchanger and pre-heater
 With no pre-heat, heat of reaction
may not achieve required inlet
temperature
 Increase carbon oxides in inlet gas by
partial by-passing of LTS or CO2
removal
Normal Operation
 Conversion of carbon oxides depends
on outlet temperature
 If CO inlet increases, exit temperature
also increases, reaction rate increases
and exit carbon oxide level decreases
 This may allow a reduction in inlet
temperature
Methanation Catalyst AgeingTemperature
Top Bed Depth Bottom
- ageing mechanism is gradual poisoning
- profile moves down the bed
Methanation Catalyst Monitoring
 Monitor Frequently:
– Inlet/Exit Temperatures
– Exit Carbon Oxides (CO + CO2)
 Monitor less Frequently:
– Pressure Drop
– Temperature profile movement with
time (poisoning rate). This is the
major parameter in assessing
Methanator Catalyst life expectancy
Prediction of Remaining Catalyst Life
0 1 2 3 4 5 6 7 8 9 10 11 12
290
300
310
320
330
Bed Depth ft
TemperatureC
Plot end of active catalyst
bed as function of time
2.8 Co
16°C
2.8 C ~ 465ppm CO2
where tangent intercepts line,
16 C above 2.8 C point
exit CO2 = 2ppm
o
o o
o
Prediction of Remaining Catalyst Life
0 2 4 6 8 10 12 14
0
2
4
6
8
10
12
14
Time on-line (years)
Effectiveendofbed(ftfrominlet)
Actual
Predicted
End of Bed
Catalyst Poisons
 S is a poison but not normally present
unless LTS by-passed
 Most poisons originate from CO2 removal
system
 Carry-over a small amount of liquid not
generally serious
 large volumes will have a serious effect
Common Poisons Effect
K2CO3 Blocks Pores; is removable
AS2O3 Serious irreversible poisoning
Sulfolane Decomposes to S; poison
CO2 Removal Systems
Process Chemical Effect
Benfield Aqueous potassium
carbonate
Blocks pores of catalyst by evaporation of K2CO3
Vetrocoke Aqueous potassium
carbonate plus
arsenious oxide
Blocks pores of catalyst by evaporation of K2CO3. As203 is
also a poison; 0.5% of As on the catalyst will reduce its
activity by 50%.
Benfield
DEA
Aqueous Potassium
carbonate with 3%
di-ethanolamine
Blocks pores of catalyst by evaporation of K2C03.
DEA is harmless
Sulphinol Sulpholane, water
di-2-propanolamine
Sulpholane will decompose and cause sulphur poisoning
MEA, DEA di-ethanolamine in aqueous
solution
None
MDEA Aqueous solution of methyl
di-ethanolamine and
activators
None
Rectisol Methanol None
Catacarb Aqueous potassium
carbonate with borate additive
Blocks pores of catalyst by evaporation of K2C03
Selexol Dimethyl ether of polyethylene
glycol
None
Unusual Operating Conditions
 High CO levels
– LTS by-passed
– total concentration of carbon oxides
<3%
– inlet temperature 210-250oC (410-480oF)
– if necessary, lower rate through HTS and
increase S/C ratio
 High water levels
– normal level 2-3% H2O in inlet gas
– if >3%, can lead to high CO2 in exit gas
– may need to increase bed inlet
temperatures
– operating experience up to 7% H2O
Plant Mal-operation
 Normal maximum exit temperatures is
450oC (840oF)
 excursion to 600oC (1100oF) for several
hours can be tolerated
 in the event of a temperature runaway,
the vessel must be protected:
– isolate on inlet side
– blow down to atmospheric
– purge with nitrogen to aid cooling
– exclude air to avoid exothermic oxidation
Abnormal Conditions
 Gradual steady rise across whole bed
• inadequate reduction?
• Poisoning?
 Sudden movement of reaction zone
with no change in slope
• poisoning of top?
• poor reduction of top?
 Normal temperature profile, high
outlet, carbon oxides
• channelling through bed?
• Mechanical problems? (bypass
valve, heat exchanger)
• analytical problems?
Nickel Carbonyl Ni(CO)4
 colorless, mobile liquid, flammable in air,
insoluble in water
 boiling point 43oC (190oF)
 vapor pressure
(oC)
-12
18
24
43
(oF)
10
64
75
109
Vp
(bar)
0.10
0.25
0.51
1.01
Vp
(psi)
1.4
3.6
7.4
14.6
EXTREMELY TOXIC
Toxicity of Ni (CO)4
 4 ppm v/v for 2 minute gives
severe toxic effects
 2 ppm v/v short time leads to
illness
 target value (daily average
concentrations) 0.001ppm v/v
Ni(s) + 4CO(g) Ni(CO)4(g)
Guidelines
 Under normal operating conditions,
concentrations are too low to be a
problem
• steam reformer has a high CO, high Ni, but
high temperatures
• after LTS, temperatures low, but low CO,
low Ni
 Under abnormal operating conditions (eg.
start-up or shut-down) it is possible to
get conditions favourable for the
formation of Ni(CO)4
Keep temperatures above
200oC (390oF) to avoid
formation of Ni(CO)4
Nickel Carbonyl Formation
Temperature oC (oF)
PartialpressureofCO(bar)
0 100 200 300 400
0.001
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
1
Favorable
Not Favorable
(32) (212) (392) (572) (752)
30 bar
1 bar
Conditions for the formation of 0.001 ppm
Catalyst Back-washing for
K2CO3 Removal
 Considerations
– catalyst strength
– water quality and temperature
– reactor cooling and purging
– plant isolations
 Catalyst performance fully regained
– CO + CO2 slip < 6ppm
– catalyst strength unaffected by
repeated washings
– no effect on catalyst pressure
drop
Ammonia Plant - Methanation Operations

Weitere ähnliche Inhalte

Was ist angesagt?

Secondary Reforming Flowsheets
Secondary Reforming FlowsheetsSecondary Reforming Flowsheets
Secondary Reforming FlowsheetsGerard B. Hawkins
 
Reduction and Start-Up of Steam Reforming Catalyst
Reduction and Start-Up of Steam Reforming CatalystReduction and Start-Up of Steam Reforming Catalyst
Reduction and Start-Up of Steam Reforming CatalystGerard B. Hawkins
 
(LTS) Low Temperature Shift Catalyst - Comprehensive Overview
(LTS) Low Temperature Shift Catalyst - Comprehensive Overview(LTS) Low Temperature Shift Catalyst - Comprehensive Overview
(LTS) Low Temperature Shift Catalyst - Comprehensive OverviewGerard B. Hawkins
 
Steam Reforming - A Comprehensive Review
Steam Reforming - A Comprehensive ReviewSteam Reforming - A Comprehensive Review
Steam Reforming - A Comprehensive ReviewGerard B. Hawkins
 
Steam Reforming - Practical Operations
Steam Reforming - Practical OperationsSteam Reforming - Practical Operations
Steam Reforming - Practical OperationsGerard B. Hawkins
 
Steam reforming - The Basics of Reforming
Steam reforming  - The Basics of ReformingSteam reforming  - The Basics of Reforming
Steam reforming - The Basics of ReformingGerard B. Hawkins
 
(HTS) High Temperature Shift Catalyst (VSG-F101) - Comprehensiev Overview
(HTS) High Temperature Shift Catalyst (VSG-F101) - Comprehensiev Overview(HTS) High Temperature Shift Catalyst (VSG-F101) - Comprehensiev Overview
(HTS) High Temperature Shift Catalyst (VSG-F101) - Comprehensiev OverviewGerard B. Hawkins
 
Feedstock Purfication in Hydrogen Plants
Feedstock Purfication in Hydrogen PlantsFeedstock Purfication in Hydrogen Plants
Feedstock Purfication in Hydrogen PlantsGerard B. Hawkins
 
High Temperature Shift Catalyst Reduction Procedure
High Temperature Shift Catalyst Reduction ProcedureHigh Temperature Shift Catalyst Reduction Procedure
High Temperature Shift Catalyst Reduction ProcedureGerard B. Hawkins
 
Various ammonia technology
Various ammonia technologyVarious ammonia technology
Various ammonia technologyPrem Baboo
 
Ammonia plant material balance
Ammonia plant material balanceAmmonia plant material balance
Ammonia plant material balancePrem Baboo
 
Normal Operation of Steam Reformers on Hydrogen Plants
Normal Operation of Steam Reformers on Hydrogen PlantsNormal Operation of Steam Reformers on Hydrogen Plants
Normal Operation of Steam Reformers on Hydrogen PlantsGerard B. Hawkins
 
Steam Reforming - Common Problems
Steam Reforming - Common ProblemsSteam Reforming - Common Problems
Steam Reforming - Common ProblemsGerard B. Hawkins
 
Steam Reforming - Tube Design
Steam Reforming - Tube DesignSteam Reforming - Tube Design
Steam Reforming - Tube DesignGerard B. Hawkins
 
Ammonia production from natural gas.
Ammonia production from natural gas.Ammonia production from natural gas.
Ammonia production from natural gas.Ajay Nagar
 

Was ist angesagt? (20)

Secondary Reforming Flowsheets
Secondary Reforming FlowsheetsSecondary Reforming Flowsheets
Secondary Reforming Flowsheets
 
Reduction and Start-Up of Steam Reforming Catalyst
Reduction and Start-Up of Steam Reforming CatalystReduction and Start-Up of Steam Reforming Catalyst
Reduction and Start-Up of Steam Reforming Catalyst
 
(LTS) Low Temperature Shift Catalyst - Comprehensive Overview
(LTS) Low Temperature Shift Catalyst - Comprehensive Overview(LTS) Low Temperature Shift Catalyst - Comprehensive Overview
(LTS) Low Temperature Shift Catalyst - Comprehensive Overview
 
Ammonia CO2 Removal Systems
Ammonia CO2 Removal SystemsAmmonia CO2 Removal Systems
Ammonia CO2 Removal Systems
 
Ammonia plant
Ammonia plantAmmonia plant
Ammonia plant
 
Steam Reforming - A Comprehensive Review
Steam Reforming - A Comprehensive ReviewSteam Reforming - A Comprehensive Review
Steam Reforming - A Comprehensive Review
 
Steam Reforming - Practical Operations
Steam Reforming - Practical OperationsSteam Reforming - Practical Operations
Steam Reforming - Practical Operations
 
Steam reforming - The Basics of Reforming
Steam reforming  - The Basics of ReformingSteam reforming  - The Basics of Reforming
Steam reforming - The Basics of Reforming
 
(HTS) High Temperature Shift Catalyst (VSG-F101) - Comprehensiev Overview
(HTS) High Temperature Shift Catalyst (VSG-F101) - Comprehensiev Overview(HTS) High Temperature Shift Catalyst (VSG-F101) - Comprehensiev Overview
(HTS) High Temperature Shift Catalyst (VSG-F101) - Comprehensiev Overview
 
Feedstock Purfication in Hydrogen Plants
Feedstock Purfication in Hydrogen PlantsFeedstock Purfication in Hydrogen Plants
Feedstock Purfication in Hydrogen Plants
 
High Temperature Shift Catalyst Reduction Procedure
High Temperature Shift Catalyst Reduction ProcedureHigh Temperature Shift Catalyst Reduction Procedure
High Temperature Shift Catalyst Reduction Procedure
 
Various ammonia technology
Various ammonia technologyVarious ammonia technology
Various ammonia technology
 
Ammonia plant material balance
Ammonia plant material balanceAmmonia plant material balance
Ammonia plant material balance
 
Normal Operation of Steam Reformers on Hydrogen Plants
Normal Operation of Steam Reformers on Hydrogen PlantsNormal Operation of Steam Reformers on Hydrogen Plants
Normal Operation of Steam Reformers on Hydrogen Plants
 
Steam Reforming - Common Problems
Steam Reforming - Common ProblemsSteam Reforming - Common Problems
Steam Reforming - Common Problems
 
Kbr
KbrKbr
Kbr
 
Steam Reforming - Tube Design
Steam Reforming - Tube DesignSteam Reforming - Tube Design
Steam Reforming - Tube Design
 
Ammonia production from natural gas.
Ammonia production from natural gas.Ammonia production from natural gas.
Ammonia production from natural gas.
 
Ammonia converter
Ammonia converterAmmonia converter
Ammonia converter
 
Activated MDEA solution(aMDEA)
Activated MDEA solution(aMDEA)Activated MDEA solution(aMDEA)
Activated MDEA solution(aMDEA)
 

Ähnlich wie Ammonia Plant - Methanation Operations

Power Plant Chemistry FEED WATER TREATMENT
Power Plant Chemistry FEED WATER TREATMENTPower Plant Chemistry FEED WATER TREATMENT
Power Plant Chemistry FEED WATER TREATMENTDilip Kumar
 
POWER PLANT CHEMISTRY
POWER PLANT CHEMISTRYPOWER PLANT CHEMISTRY
POWER PLANT CHEMISTRYDilip Kumar
 
Pre-reformer Operations Technical Supplement
Pre-reformer Operations Technical SupplementPre-reformer Operations Technical Supplement
Pre-reformer Operations Technical SupplementGerard B. Hawkins
 
Amm plant description
Amm plant descriptionAmm plant description
Amm plant descriptionameermudasar
 
Sces2340 p3 hydrogen_synthesis_041218
Sces2340 p3 hydrogen_synthesis_041218Sces2340 p3 hydrogen_synthesis_041218
Sces2340 p3 hydrogen_synthesis_041218Nazrul Amin Muhammad
 
ALD Vacuum Carburizing and Low Pressure Carburizing | LPC
ALD Vacuum Carburizing and Low Pressure Carburizing | LPCALD Vacuum Carburizing and Low Pressure Carburizing | LPC
ALD Vacuum Carburizing and Low Pressure Carburizing | LPCALD Vacuum Systems Inc.
 
Sweetening and sulfur recovery of sour associated gas in the middle east
Sweetening and sulfur recovery of sour associated gas in the middle eastSweetening and sulfur recovery of sour associated gas in the middle east
Sweetening and sulfur recovery of sour associated gas in the middle eastFrames
 
Fischer_Tropsch_Catalysts.pdf
Fischer_Tropsch_Catalysts.pdfFischer_Tropsch_Catalysts.pdf
Fischer_Tropsch_Catalysts.pdfpeyman40
 
Methanol Synthesis - Theory and Operation
Methanol Synthesis - Theory and OperationMethanol Synthesis - Theory and Operation
Methanol Synthesis - Theory and OperationGerard B. Hawkins
 
Air pollution in thermal power plants
Air pollution in thermal power plantsAir pollution in thermal power plants
Air pollution in thermal power plantsMahima Susan George
 

Ähnlich wie Ammonia Plant - Methanation Operations (20)

CO2QUEST Typical Impurities in Captured CO2 Streams - Richard T. J. Porter at...
CO2QUEST Typical Impurities in Captured CO2 Streams - Richard T. J. Porter at...CO2QUEST Typical Impurities in Captured CO2 Streams - Richard T. J. Porter at...
CO2QUEST Typical Impurities in Captured CO2 Streams - Richard T. J. Porter at...
 
Power Plant Chemistry FEED WATER TREATMENT
Power Plant Chemistry FEED WATER TREATMENTPower Plant Chemistry FEED WATER TREATMENT
Power Plant Chemistry FEED WATER TREATMENT
 
POWER PLANT CHEMISTRY
POWER PLANT CHEMISTRYPOWER PLANT CHEMISTRY
POWER PLANT CHEMISTRY
 
CO2 REVAL SECTION .2022.pptx
CO2 REVAL SECTION .2022.pptxCO2 REVAL SECTION .2022.pptx
CO2 REVAL SECTION .2022.pptx
 
Pre-reformer Operations Technical Supplement
Pre-reformer Operations Technical SupplementPre-reformer Operations Technical Supplement
Pre-reformer Operations Technical Supplement
 
Amm plant description
Amm plant descriptionAmm plant description
Amm plant description
 
CATALYST.ppt
CATALYST.pptCATALYST.ppt
CATALYST.ppt
 
CATALYST.ppt
CATALYST.pptCATALYST.ppt
CATALYST.ppt
 
FCC Off Gas Treatment
FCC Off Gas TreatmentFCC Off Gas Treatment
FCC Off Gas Treatment
 
Sces2340 p3 hydrogen_synthesis_041218
Sces2340 p3 hydrogen_synthesis_041218Sces2340 p3 hydrogen_synthesis_041218
Sces2340 p3 hydrogen_synthesis_041218
 
ALD Vacuum Carburizing and Low Pressure Carburizing | LPC
ALD Vacuum Carburizing and Low Pressure Carburizing | LPCALD Vacuum Carburizing and Low Pressure Carburizing | LPC
ALD Vacuum Carburizing and Low Pressure Carburizing | LPC
 
Sweetening and sulfur recovery of sour associated gas in the middle east
Sweetening and sulfur recovery of sour associated gas in the middle eastSweetening and sulfur recovery of sour associated gas in the middle east
Sweetening and sulfur recovery of sour associated gas in the middle east
 
Ammonia Industries
Ammonia IndustriesAmmonia Industries
Ammonia Industries
 
GEO's Presentation on In Situ Thermal Remediation to EPA Region 9
GEO's Presentation on In Situ Thermal Remediation to EPA Region 9GEO's Presentation on In Situ Thermal Remediation to EPA Region 9
GEO's Presentation on In Situ Thermal Remediation to EPA Region 9
 
Fischer_Tropsch_Catalysts.pdf
Fischer_Tropsch_Catalysts.pdfFischer_Tropsch_Catalysts.pdf
Fischer_Tropsch_Catalysts.pdf
 
Methanol Synthesis - Theory and Operation
Methanol Synthesis - Theory and OperationMethanol Synthesis - Theory and Operation
Methanol Synthesis - Theory and Operation
 
Air pollution in thermal power plants
Air pollution in thermal power plantsAir pollution in thermal power plants
Air pollution in thermal power plants
 
Bwt
BwtBwt
Bwt
 
Nitric acid Industries
Nitric acid IndustriesNitric acid Industries
Nitric acid Industries
 
Ppt assgn 1
Ppt assgn  1Ppt assgn  1
Ppt assgn 1
 

Mehr von Gerard B. Hawkins

Pressure Relief Systems Vol 2
Pressure Relief Systems   Vol 2Pressure Relief Systems   Vol 2
Pressure Relief Systems Vol 2Gerard B. Hawkins
 
GAS DISPERSION - A Definitive Guide to Accidental Releases of Heavy Gases
GAS DISPERSION -  A Definitive Guide to Accidental Releases of Heavy GasesGAS DISPERSION -  A Definitive Guide to Accidental Releases of Heavy Gases
GAS DISPERSION - A Definitive Guide to Accidental Releases of Heavy GasesGerard B. Hawkins
 
101 Things That Can Go Wrong on a Primary Reformer - Best Practices Guide
101 Things That Can Go Wrong on a Primary Reformer -  Best Practices Guide101 Things That Can Go Wrong on a Primary Reformer -  Best Practices Guide
101 Things That Can Go Wrong on a Primary Reformer - Best Practices GuideGerard B. Hawkins
 
El impacto en el rendimiento del catalizador por envenenamiento y ensuciamien...
El impacto en el rendimiento del catalizador por envenenamiento y ensuciamien...El impacto en el rendimiento del catalizador por envenenamiento y ensuciamien...
El impacto en el rendimiento del catalizador por envenenamiento y ensuciamien...Gerard B. Hawkins
 
Theory of Carbon Formation in Steam Reforming
Theory of Carbon Formation in Steam Reforming Theory of Carbon Formation in Steam Reforming
Theory of Carbon Formation in Steam Reforming Gerard B. Hawkins
 
Adiabatic Reactor Analysis for Methanol Synthesis Plant Note Book Series: P...
Adiabatic Reactor Analysis for Methanol Synthesis   Plant Note Book Series: P...Adiabatic Reactor Analysis for Methanol Synthesis   Plant Note Book Series: P...
Adiabatic Reactor Analysis for Methanol Synthesis Plant Note Book Series: P...Gerard B. Hawkins
 
STEAMING PROCEDURE FOR VULCAN STEAM REFORMING CATALYSTS
STEAMING PROCEDURE FOR VULCAN STEAM REFORMING CATALYSTSSTEAMING PROCEDURE FOR VULCAN STEAM REFORMING CATALYSTS
STEAMING PROCEDURE FOR VULCAN STEAM REFORMING CATALYSTSGerard B. Hawkins
 
Calculation of an Ammonia Plant Energy Consumption:
Calculation of an Ammonia Plant Energy Consumption:  Calculation of an Ammonia Plant Energy Consumption:
Calculation of an Ammonia Plant Energy Consumption: Gerard B. Hawkins
 
Calculation of Caloric Value and other Characteristic Data of Fuel Gas
Calculation of Caloric Value and other Characteristic Data of Fuel GasCalculation of Caloric Value and other Characteristic Data of Fuel Gas
Calculation of Caloric Value and other Characteristic Data of Fuel GasGerard B. Hawkins
 
Piping and Vessels Flushing and Cleaning Procedure
Piping and Vessels Flushing and Cleaning ProcedurePiping and Vessels Flushing and Cleaning Procedure
Piping and Vessels Flushing and Cleaning ProcedureGerard B. Hawkins
 
DESIGN OF VENT GAS COLLECTION AND DESTRUCTION SYSTEMS
DESIGN OF VENT GAS COLLECTION AND DESTRUCTION SYSTEMS DESIGN OF VENT GAS COLLECTION AND DESTRUCTION SYSTEMS
DESIGN OF VENT GAS COLLECTION AND DESTRUCTION SYSTEMS Gerard B. Hawkins
 
PRACTICAL GUIDE ON THE SELECTION OF PROCESS TECHNOLOGY FOR THE TREATMENT OF A...
PRACTICAL GUIDE ON THE SELECTION OF PROCESS TECHNOLOGY FOR THE TREATMENT OF A...PRACTICAL GUIDE ON THE SELECTION OF PROCESS TECHNOLOGY FOR THE TREATMENT OF A...
PRACTICAL GUIDE ON THE SELECTION OF PROCESS TECHNOLOGY FOR THE TREATMENT OF A...Gerard B. Hawkins
 
PRACTICAL GUIDE ON THE REDUCTION OF DISCHARGES TO ATMOSPHERE OF VOLATILE ORGA...
PRACTICAL GUIDE ON THE REDUCTION OF DISCHARGES TO ATMOSPHERE OF VOLATILE ORGA...PRACTICAL GUIDE ON THE REDUCTION OF DISCHARGES TO ATMOSPHERE OF VOLATILE ORGA...
PRACTICAL GUIDE ON THE REDUCTION OF DISCHARGES TO ATMOSPHERE OF VOLATILE ORGA...Gerard B. Hawkins
 
Getting the Most Out of Your Refinery Hydrogen Plant
Getting the Most Out of Your Refinery Hydrogen PlantGetting the Most Out of Your Refinery Hydrogen Plant
Getting the Most Out of Your Refinery Hydrogen PlantGerard B. Hawkins
 
EMERGENCY ISOLATION OF CHEMICAL PLANTS
EMERGENCY ISOLATION OF CHEMICAL PLANTS EMERGENCY ISOLATION OF CHEMICAL PLANTS
EMERGENCY ISOLATION OF CHEMICAL PLANTS Gerard B. Hawkins
 
PRACTICAL GUIDE TO DEVELOPING PROCESS FLOW DIAGRAMS AND PRELIMINARY ENGINEER...
PRACTICAL GUIDE TO DEVELOPING PROCESS FLOW DIAGRAMS AND  PRELIMINARY ENGINEER...PRACTICAL GUIDE TO DEVELOPING PROCESS FLOW DIAGRAMS AND  PRELIMINARY ENGINEER...
PRACTICAL GUIDE TO DEVELOPING PROCESS FLOW DIAGRAMS AND PRELIMINARY ENGINEER...Gerard B. Hawkins
 
Purificación – Mecanismos de Reacción
Purificación – Mecanismos de Reacción Purificación – Mecanismos de Reacción
Purificación – Mecanismos de Reacción Gerard B. Hawkins
 
Amine Gas Treating Unit - Best Practices - Troubleshooting Guide
Amine Gas Treating Unit  - Best Practices - Troubleshooting Guide Amine Gas Treating Unit  - Best Practices - Troubleshooting Guide
Amine Gas Treating Unit - Best Practices - Troubleshooting Guide Gerard B. Hawkins
 

Mehr von Gerard B. Hawkins (20)

Pressure Relief Systems Vol 2
Pressure Relief Systems   Vol 2Pressure Relief Systems   Vol 2
Pressure Relief Systems Vol 2
 
Pressure Relief Systems
Pressure Relief Systems Pressure Relief Systems
Pressure Relief Systems
 
GAS DISPERSION - A Definitive Guide to Accidental Releases of Heavy Gases
GAS DISPERSION -  A Definitive Guide to Accidental Releases of Heavy GasesGAS DISPERSION -  A Definitive Guide to Accidental Releases of Heavy Gases
GAS DISPERSION - A Definitive Guide to Accidental Releases of Heavy Gases
 
101 Things That Can Go Wrong on a Primary Reformer - Best Practices Guide
101 Things That Can Go Wrong on a Primary Reformer -  Best Practices Guide101 Things That Can Go Wrong on a Primary Reformer -  Best Practices Guide
101 Things That Can Go Wrong on a Primary Reformer - Best Practices Guide
 
El impacto en el rendimiento del catalizador por envenenamiento y ensuciamien...
El impacto en el rendimiento del catalizador por envenenamiento y ensuciamien...El impacto en el rendimiento del catalizador por envenenamiento y ensuciamien...
El impacto en el rendimiento del catalizador por envenenamiento y ensuciamien...
 
Theory of Carbon Formation in Steam Reforming
Theory of Carbon Formation in Steam Reforming Theory of Carbon Formation in Steam Reforming
Theory of Carbon Formation in Steam Reforming
 
Adiabatic Reactor Analysis for Methanol Synthesis Plant Note Book Series: P...
Adiabatic Reactor Analysis for Methanol Synthesis   Plant Note Book Series: P...Adiabatic Reactor Analysis for Methanol Synthesis   Plant Note Book Series: P...
Adiabatic Reactor Analysis for Methanol Synthesis Plant Note Book Series: P...
 
STEAMING PROCEDURE FOR VULCAN STEAM REFORMING CATALYSTS
STEAMING PROCEDURE FOR VULCAN STEAM REFORMING CATALYSTSSTEAMING PROCEDURE FOR VULCAN STEAM REFORMING CATALYSTS
STEAMING PROCEDURE FOR VULCAN STEAM REFORMING CATALYSTS
 
Calculation of an Ammonia Plant Energy Consumption:
Calculation of an Ammonia Plant Energy Consumption:  Calculation of an Ammonia Plant Energy Consumption:
Calculation of an Ammonia Plant Energy Consumption:
 
Calculation of Caloric Value and other Characteristic Data of Fuel Gas
Calculation of Caloric Value and other Characteristic Data of Fuel GasCalculation of Caloric Value and other Characteristic Data of Fuel Gas
Calculation of Caloric Value and other Characteristic Data of Fuel Gas
 
Pickling & Passivation
Pickling & PassivationPickling & Passivation
Pickling & Passivation
 
Piping and Vessels Flushing and Cleaning Procedure
Piping and Vessels Flushing and Cleaning ProcedurePiping and Vessels Flushing and Cleaning Procedure
Piping and Vessels Flushing and Cleaning Procedure
 
DESIGN OF VENT GAS COLLECTION AND DESTRUCTION SYSTEMS
DESIGN OF VENT GAS COLLECTION AND DESTRUCTION SYSTEMS DESIGN OF VENT GAS COLLECTION AND DESTRUCTION SYSTEMS
DESIGN OF VENT GAS COLLECTION AND DESTRUCTION SYSTEMS
 
PRACTICAL GUIDE ON THE SELECTION OF PROCESS TECHNOLOGY FOR THE TREATMENT OF A...
PRACTICAL GUIDE ON THE SELECTION OF PROCESS TECHNOLOGY FOR THE TREATMENT OF A...PRACTICAL GUIDE ON THE SELECTION OF PROCESS TECHNOLOGY FOR THE TREATMENT OF A...
PRACTICAL GUIDE ON THE SELECTION OF PROCESS TECHNOLOGY FOR THE TREATMENT OF A...
 
PRACTICAL GUIDE ON THE REDUCTION OF DISCHARGES TO ATMOSPHERE OF VOLATILE ORGA...
PRACTICAL GUIDE ON THE REDUCTION OF DISCHARGES TO ATMOSPHERE OF VOLATILE ORGA...PRACTICAL GUIDE ON THE REDUCTION OF DISCHARGES TO ATMOSPHERE OF VOLATILE ORGA...
PRACTICAL GUIDE ON THE REDUCTION OF DISCHARGES TO ATMOSPHERE OF VOLATILE ORGA...
 
Getting the Most Out of Your Refinery Hydrogen Plant
Getting the Most Out of Your Refinery Hydrogen PlantGetting the Most Out of Your Refinery Hydrogen Plant
Getting the Most Out of Your Refinery Hydrogen Plant
 
EMERGENCY ISOLATION OF CHEMICAL PLANTS
EMERGENCY ISOLATION OF CHEMICAL PLANTS EMERGENCY ISOLATION OF CHEMICAL PLANTS
EMERGENCY ISOLATION OF CHEMICAL PLANTS
 
PRACTICAL GUIDE TO DEVELOPING PROCESS FLOW DIAGRAMS AND PRELIMINARY ENGINEER...
PRACTICAL GUIDE TO DEVELOPING PROCESS FLOW DIAGRAMS AND  PRELIMINARY ENGINEER...PRACTICAL GUIDE TO DEVELOPING PROCESS FLOW DIAGRAMS AND  PRELIMINARY ENGINEER...
PRACTICAL GUIDE TO DEVELOPING PROCESS FLOW DIAGRAMS AND PRELIMINARY ENGINEER...
 
Purificación – Mecanismos de Reacción
Purificación – Mecanismos de Reacción Purificación – Mecanismos de Reacción
Purificación – Mecanismos de Reacción
 
Amine Gas Treating Unit - Best Practices - Troubleshooting Guide
Amine Gas Treating Unit  - Best Practices - Troubleshooting Guide Amine Gas Treating Unit  - Best Practices - Troubleshooting Guide
Amine Gas Treating Unit - Best Practices - Troubleshooting Guide
 

Kürzlich hochgeladen

NIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopNIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopBachir Benyammi
 
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...Will Schroeder
 
Building Your Own AI Instance (TBLC AI )
Building Your Own AI Instance (TBLC AI )Building Your Own AI Instance (TBLC AI )
Building Your Own AI Instance (TBLC AI )Brian Pichman
 
Building AI-Driven Apps Using Semantic Kernel.pptx
Building AI-Driven Apps Using Semantic Kernel.pptxBuilding AI-Driven Apps Using Semantic Kernel.pptx
Building AI-Driven Apps Using Semantic Kernel.pptxUdaiappa Ramachandran
 
Designing A Time bound resource download URL
Designing A Time bound resource download URLDesigning A Time bound resource download URL
Designing A Time bound resource download URLRuncy Oommen
 
UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6DianaGray10
 
Machine Learning Model Validation (Aijun Zhang 2024).pdf
Machine Learning Model Validation (Aijun Zhang 2024).pdfMachine Learning Model Validation (Aijun Zhang 2024).pdf
Machine Learning Model Validation (Aijun Zhang 2024).pdfAijun Zhang
 
Basic Building Blocks of Internet of Things.
Basic Building Blocks of Internet of Things.Basic Building Blocks of Internet of Things.
Basic Building Blocks of Internet of Things.YounusS2
 
Computer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and HazardsComputer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and HazardsSeth Reyes
 
UiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation DevelopersUiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation DevelopersUiPathCommunity
 
Nanopower In Semiconductor Industry.pdf
Nanopower  In Semiconductor Industry.pdfNanopower  In Semiconductor Industry.pdf
Nanopower In Semiconductor Industry.pdfPedro Manuel
 
Introduction to Matsuo Laboratory (ENG).pptx
Introduction to Matsuo Laboratory (ENG).pptxIntroduction to Matsuo Laboratory (ENG).pptx
Introduction to Matsuo Laboratory (ENG).pptxMatsuo Lab
 
OpenShift Commons Paris - Choose Your Own Observability Adventure
OpenShift Commons Paris - Choose Your Own Observability AdventureOpenShift Commons Paris - Choose Your Own Observability Adventure
OpenShift Commons Paris - Choose Your Own Observability AdventureEric D. Schabell
 
AI You Can Trust - Ensuring Success with Data Integrity Webinar
AI You Can Trust - Ensuring Success with Data Integrity WebinarAI You Can Trust - Ensuring Success with Data Integrity Webinar
AI You Can Trust - Ensuring Success with Data Integrity WebinarPrecisely
 
COMPUTER 10: Lesson 7 - File Storage and Online Collaboration
COMPUTER 10: Lesson 7 - File Storage and Online CollaborationCOMPUTER 10: Lesson 7 - File Storage and Online Collaboration
COMPUTER 10: Lesson 7 - File Storage and Online Collaborationbruanjhuli
 
20230202 - Introduction to tis-py
20230202 - Introduction to tis-py20230202 - Introduction to tis-py
20230202 - Introduction to tis-pyJamie (Taka) Wang
 
Bird eye's view on Camunda open source ecosystem
Bird eye's view on Camunda open source ecosystemBird eye's view on Camunda open source ecosystem
Bird eye's view on Camunda open source ecosystemAsko Soukka
 
UiPath Platform: The Backend Engine Powering Your Automation - Session 1
UiPath Platform: The Backend Engine Powering Your Automation - Session 1UiPath Platform: The Backend Engine Powering Your Automation - Session 1
UiPath Platform: The Backend Engine Powering Your Automation - Session 1DianaGray10
 
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPA
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPAAnypoint Code Builder , Google Pub sub connector and MuleSoft RPA
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPAshyamraj55
 

Kürzlich hochgeladen (20)

NIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopNIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 Workshop
 
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
 
Building Your Own AI Instance (TBLC AI )
Building Your Own AI Instance (TBLC AI )Building Your Own AI Instance (TBLC AI )
Building Your Own AI Instance (TBLC AI )
 
Building AI-Driven Apps Using Semantic Kernel.pptx
Building AI-Driven Apps Using Semantic Kernel.pptxBuilding AI-Driven Apps Using Semantic Kernel.pptx
Building AI-Driven Apps Using Semantic Kernel.pptx
 
Designing A Time bound resource download URL
Designing A Time bound resource download URLDesigning A Time bound resource download URL
Designing A Time bound resource download URL
 
201610817 - edge part1
201610817 - edge part1201610817 - edge part1
201610817 - edge part1
 
UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6
 
Machine Learning Model Validation (Aijun Zhang 2024).pdf
Machine Learning Model Validation (Aijun Zhang 2024).pdfMachine Learning Model Validation (Aijun Zhang 2024).pdf
Machine Learning Model Validation (Aijun Zhang 2024).pdf
 
Basic Building Blocks of Internet of Things.
Basic Building Blocks of Internet of Things.Basic Building Blocks of Internet of Things.
Basic Building Blocks of Internet of Things.
 
Computer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and HazardsComputer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and Hazards
 
UiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation DevelopersUiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation Developers
 
Nanopower In Semiconductor Industry.pdf
Nanopower  In Semiconductor Industry.pdfNanopower  In Semiconductor Industry.pdf
Nanopower In Semiconductor Industry.pdf
 
Introduction to Matsuo Laboratory (ENG).pptx
Introduction to Matsuo Laboratory (ENG).pptxIntroduction to Matsuo Laboratory (ENG).pptx
Introduction to Matsuo Laboratory (ENG).pptx
 
OpenShift Commons Paris - Choose Your Own Observability Adventure
OpenShift Commons Paris - Choose Your Own Observability AdventureOpenShift Commons Paris - Choose Your Own Observability Adventure
OpenShift Commons Paris - Choose Your Own Observability Adventure
 
AI You Can Trust - Ensuring Success with Data Integrity Webinar
AI You Can Trust - Ensuring Success with Data Integrity WebinarAI You Can Trust - Ensuring Success with Data Integrity Webinar
AI You Can Trust - Ensuring Success with Data Integrity Webinar
 
COMPUTER 10: Lesson 7 - File Storage and Online Collaboration
COMPUTER 10: Lesson 7 - File Storage and Online CollaborationCOMPUTER 10: Lesson 7 - File Storage and Online Collaboration
COMPUTER 10: Lesson 7 - File Storage and Online Collaboration
 
20230202 - Introduction to tis-py
20230202 - Introduction to tis-py20230202 - Introduction to tis-py
20230202 - Introduction to tis-py
 
Bird eye's view on Camunda open source ecosystem
Bird eye's view on Camunda open source ecosystemBird eye's view on Camunda open source ecosystem
Bird eye's view on Camunda open source ecosystem
 
UiPath Platform: The Backend Engine Powering Your Automation - Session 1
UiPath Platform: The Backend Engine Powering Your Automation - Session 1UiPath Platform: The Backend Engine Powering Your Automation - Session 1
UiPath Platform: The Backend Engine Powering Your Automation - Session 1
 
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPA
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPAAnypoint Code Builder , Google Pub sub connector and MuleSoft RPA
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPA
 

Ammonia Plant - Methanation Operations

  • 1. Ammonia Plant - Methanation Operations By: Gerard B. Hawkins Managing Director, CEO
  • 2. Methanation • Introduction and Theoretical Aspects • Catalyst Reduction and Start-up • Normal Operation and Troubleshooting • Shutdown and Catalyst Discharge • Nickel Carbonyl Hazard • Modern Methanation Catalyst Requirements
  • 3. Introduction  Carbon oxides are poisons for ammonia synthesis catalyst  Methanation is the final stage of purification of synthesis gas after CO2 removal to reduce carbon oxides to trace levels  Uses nickel-based catalyst
  • 4. Methanation Reactions & Operating Conditions  Reactions are highly exothermic • +74oC (133oF) for every 1% CO converted • +60oC (108oF) for every 1% CO2 converted  Typical inlet temperatures • 270-290oC (520-555oF)  Typical inlet carbon dioxide • 0.1 - 1.0 vol%  Typical carbon oxide slip • <5 ppmv CO + 3H2 CH4 + H2O ∆H= -206 kJ/mol CO2 + 4H2 CH4 + 2H2O ∆H = -165 kJ/mol
  • 5. Mechanism of Reaction  Equilibrium concentrations of carbon oxides 10ppm  Governed by kinetics  CO inhibits methanation of CO2  Two stage reaction: CO2 reverse -shifts to CO CO2 + H2 CO + H2O CO methanates CO + 3H2 CH4 + H2O  Intrinsic reaction rates very high (diffusion limited at higher temperature)
  • 6. Typical Flowsheet Gas from CO2 Removal 290oC (554oF) Process gas to Ammonia Loop 318oC (604oF) Inlet Composition (vol % dry) CO2 CO H2 CH4 N2+A 0.3 0.1 74.7 0.3 24.6 Outlet Composition (vol % dry) CO2 CO H2 CH4 N2+A <5ppm 74.2 0.8 25.0
  • 7. Methanator METHANATOR CATALYST VSG-N101 Medium bauxalite (40mm x 60mm) Flat Mesh 75 mm layer small bauxalite 150 mm layer large bauxalite (60mm x 90mm) large bauxalite (60mm x 90mm) 25 mm layer small bauxalite (25mm x 40mm)
  • 8. Catalyst Composition  Iron originally studied  Ruthenium good at low temperature (“ultra - methanation”)  Nickel conventionally used  Support matrix with 20-40% nickel  Promoters to reduce sintering  Small pellets (5mm x 3mm)  Low temperature operation  210-230oC (410-445oF)  Therefore low COx slip, < 5 ppm  Long lifetimes proven in service  VSG-N101 and VSG-N102 (Both available as Pre-reduced)
  • 9. Methanation Catalyst SV & Inlet Temperature SV (Hr )-1 220 240 260 280 300 320 340 360 2,000 4,000 6,000 8,000 10,000 Inlet Temperature ( C) VSG-N101 VSG-N102 Competitor o
  • 10. Methanation Temperature Profile 240 245 250 255 260 265 2 2.5 3 3.5 4 4.5 5 5.5 6 Bed depth (m) Temperature(DegC)1000 te/day Ammonia Plant in PR China VULCAN VSG-N101-Series Catalyst
  • 11. Catalyst Reduction  If catalyst supplied in the oxidised form must be reduced in the reactor to the active nickel form  NiO + H2 Ni + H2O ∆H = + 3 KJ/mol  NiO + CO Ni + CO2 ∆H = - 30KJ/mol  Reduction process gives little temperature rise  BUT - metallic nickel will lead to methanation during reduction  THEREFORE - reduction gas should not contain carbon dioxide (<1%)  Need to heat catalyst to 400-450oC (750-840oF) for maximum activity
  • 12. Reduction Procedure  Purge methanator free of air with N2  Heat catalyst to 200oC (390oF) in process gas, N2 or NG – do not use NG at temperatures above 200oC (390oF) due to possible methane cracking occurring  Reduction starts around 200-250oC (390-480oF) – temperature will rise – limit carbon oxides in feed to <1% – control inlet temperature
  • 13. Reduction Procedure (con’t)  Increase inlet temperature to 325-350oC (620- 660oF) – 25oC (45oF) per hour – maintain until bed exit temperature equals maximum in bed – takes about 6 hours  Increase catalyst temperature to 400-450oC (750-840oF) for a few hours – max temperature 450oC (840oF) – may need controlled bypass of LTS to increase CO content of inlet  Decrease bed inlet temperature to design, increase plant rates
  • 14. Methanation Catalyst Reduction 400 300 200 100 0 10 20 0 10 20 10 20 30 40 50 60 70 Begin End Exit Inlet CO CO Time (hr) TemperatureC(F) Time (hr) ExitCOandCO2(ppm) (212) (392) (572) (752) Partial by-pass of LTS oo 2
  • 15. Methanation Catalyst Reduction Depth m (ft) Inlet Exit Flow 70% Design Inlet CO 0.09% Inlet CO2 0.11% Partial LTS Slip (Inlet CO 0.35%) * On line TemperatureC(F) 1 2 3 (3) (6) (9) 250 (482) 300 (572) 350 (662) 2 3.5 5 7 * 24 Time (hr) oo
  • 16. Pre-reduced Methanation Catalyst  Catalyst first reduced, then partially stabilised – Faster plant start-up – Higher catalyst activity  Reduction taken place under controlled conditions – Higher Ni surface area  Lower inlet temperatures possible. – Minimum inlet temperature 170oC (338oF)  Catalyst is ready to go  Do not need to load full charge - only top portion needs to be pre reduced
  • 17. Inlet Temperature  Usually controlled by inlet/outlet gas heat exchanger and pre-heater  With no pre-heat, heat of reaction may not achieve required inlet temperature  Increase carbon oxides in inlet gas by partial by-passing of LTS or CO2 removal
  • 18. Normal Operation  Conversion of carbon oxides depends on outlet temperature  If CO inlet increases, exit temperature also increases, reaction rate increases and exit carbon oxide level decreases  This may allow a reduction in inlet temperature
  • 19. Methanation Catalyst AgeingTemperature Top Bed Depth Bottom - ageing mechanism is gradual poisoning - profile moves down the bed
  • 20. Methanation Catalyst Monitoring  Monitor Frequently: – Inlet/Exit Temperatures – Exit Carbon Oxides (CO + CO2)  Monitor less Frequently: – Pressure Drop – Temperature profile movement with time (poisoning rate). This is the major parameter in assessing Methanator Catalyst life expectancy
  • 21. Prediction of Remaining Catalyst Life 0 1 2 3 4 5 6 7 8 9 10 11 12 290 300 310 320 330 Bed Depth ft TemperatureC Plot end of active catalyst bed as function of time 2.8 Co 16°C 2.8 C ~ 465ppm CO2 where tangent intercepts line, 16 C above 2.8 C point exit CO2 = 2ppm o o o o
  • 22. Prediction of Remaining Catalyst Life 0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 14 Time on-line (years) Effectiveendofbed(ftfrominlet) Actual Predicted End of Bed
  • 23. Catalyst Poisons  S is a poison but not normally present unless LTS by-passed  Most poisons originate from CO2 removal system  Carry-over a small amount of liquid not generally serious  large volumes will have a serious effect Common Poisons Effect K2CO3 Blocks Pores; is removable AS2O3 Serious irreversible poisoning Sulfolane Decomposes to S; poison
  • 24. CO2 Removal Systems Process Chemical Effect Benfield Aqueous potassium carbonate Blocks pores of catalyst by evaporation of K2CO3 Vetrocoke Aqueous potassium carbonate plus arsenious oxide Blocks pores of catalyst by evaporation of K2CO3. As203 is also a poison; 0.5% of As on the catalyst will reduce its activity by 50%. Benfield DEA Aqueous Potassium carbonate with 3% di-ethanolamine Blocks pores of catalyst by evaporation of K2C03. DEA is harmless Sulphinol Sulpholane, water di-2-propanolamine Sulpholane will decompose and cause sulphur poisoning MEA, DEA di-ethanolamine in aqueous solution None MDEA Aqueous solution of methyl di-ethanolamine and activators None Rectisol Methanol None Catacarb Aqueous potassium carbonate with borate additive Blocks pores of catalyst by evaporation of K2C03 Selexol Dimethyl ether of polyethylene glycol None
  • 25. Unusual Operating Conditions  High CO levels – LTS by-passed – total concentration of carbon oxides <3% – inlet temperature 210-250oC (410-480oF) – if necessary, lower rate through HTS and increase S/C ratio  High water levels – normal level 2-3% H2O in inlet gas – if >3%, can lead to high CO2 in exit gas – may need to increase bed inlet temperatures – operating experience up to 7% H2O
  • 26. Plant Mal-operation  Normal maximum exit temperatures is 450oC (840oF)  excursion to 600oC (1100oF) for several hours can be tolerated  in the event of a temperature runaway, the vessel must be protected: – isolate on inlet side – blow down to atmospheric – purge with nitrogen to aid cooling – exclude air to avoid exothermic oxidation
  • 27. Abnormal Conditions  Gradual steady rise across whole bed • inadequate reduction? • Poisoning?  Sudden movement of reaction zone with no change in slope • poisoning of top? • poor reduction of top?  Normal temperature profile, high outlet, carbon oxides • channelling through bed? • Mechanical problems? (bypass valve, heat exchanger) • analytical problems?
  • 28. Nickel Carbonyl Ni(CO)4  colorless, mobile liquid, flammable in air, insoluble in water  boiling point 43oC (190oF)  vapor pressure (oC) -12 18 24 43 (oF) 10 64 75 109 Vp (bar) 0.10 0.25 0.51 1.01 Vp (psi) 1.4 3.6 7.4 14.6 EXTREMELY TOXIC
  • 29. Toxicity of Ni (CO)4  4 ppm v/v for 2 minute gives severe toxic effects  2 ppm v/v short time leads to illness  target value (daily average concentrations) 0.001ppm v/v Ni(s) + 4CO(g) Ni(CO)4(g)
  • 30. Guidelines  Under normal operating conditions, concentrations are too low to be a problem • steam reformer has a high CO, high Ni, but high temperatures • after LTS, temperatures low, but low CO, low Ni  Under abnormal operating conditions (eg. start-up or shut-down) it is possible to get conditions favourable for the formation of Ni(CO)4 Keep temperatures above 200oC (390oF) to avoid formation of Ni(CO)4
  • 31. Nickel Carbonyl Formation Temperature oC (oF) PartialpressureofCO(bar) 0 100 200 300 400 0.001 0.002 0.005 0.01 0.02 0.05 0.1 0.2 0.5 1 Favorable Not Favorable (32) (212) (392) (572) (752) 30 bar 1 bar Conditions for the formation of 0.001 ppm
  • 32. Catalyst Back-washing for K2CO3 Removal  Considerations – catalyst strength – water quality and temperature – reactor cooling and purging – plant isolations  Catalyst performance fully regained – CO + CO2 slip < 6ppm – catalyst strength unaffected by repeated washings – no effect on catalyst pressure drop