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Packed Beds for Processing Associated and Stranded Gas
Jonathan Lee, Chukwuma Anyigor
School of Chemical Engineering and Advanced Materials
Newcastle University.
Intensification
Talk Outline
• Associated and Stranded Gas
• Options for Stranded Gas
• Gas Processing Plant
• Process Intensification for Stranded Gas
21/5/2014 PIN meeting, Newcastle
Gas
21/5/2014 PIN meeting, Newcastle
• Abundant Reserve - (161 x 1012 m3)
• Low Carbon fuel (compared to coal/oil)
• Expensive to transport
• Typically contains:- C1 – C6 hydrocarbons- acid gases (H2S and CO2)- water- nitrogen and trace impurities
• 40 - 60% of the world’s natural gas is stranded gas.
Associated Gas
21/5/2014 PIN meeting, Newcastle
oil field
Associated Gas
• In 2009 150 billion m3 of associated gas were flared1.
• Equivalent to 25% of United States and 30% of EU gas consumption.
• Uses could include- Power generation- Enhanced Oil Recovery- Petrochemicals
Stranded Gas - I
21/5/2014 PIN meeting, Newcastle
Gas that has been produced and processed but is geographically isolated from a market
http://www.factbook2011.eni.com/
Stranded Gas - II
21/5/2014 PIN meeting, Newcastle
100 km
Sokoto
EmbaymentChad Basin
Benue Trough
Apambra
Basin
Bida
Basin
Trans-Saharan gas pipeline
Options for Stranded Gas
21/5/2014 PIN meeting, Newcastle
Remote Gas
Supply
Major Gas
Market
Adapted from Wood, Ref 2.
Pipeline
Liquified Natural Gas
Gas to Liquid
Gas to Wire
Compressed Natural Gas
Gas to Solids
Gas pipe ≈ 2 - 4 million dollars per mile
Options for Stranded Gas
21/5/2014 PIN meeting, Newcastle
• Khalilpour3 considered three options:– Liquified natural gas (LNG)
– Compressed natural gas (CNG)
– Gas to liquids (GTL)
• Historical data for capital and operating costs were used.
• Assumption was made that pipeline specification gas was available at market price.
• Oil price and gas price treated as ranged, random variables.
Options for Stranded Gas
21/5/2014 PIN meeting, Newcastle
1 nautical mile = 1.85 km 1 x 1012 ft3 = 28.3 x 109 m3
10000
9000
8000
7000
6000
5000
4000
3000
2000
1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Dis
tan
ce t
o m
arke
t (n
auti
cal m
iles)
Reservoir Recoverable Feed Gas Capacity (cubic feet x 1012)
Gas To Liquid (GTL)
Compressed Natural Gas (CNG)
Liquified Natural Gas (LNG)
Can Process Intensification move any of these boundaries?
Gas Processing
21/5/2014 PIN meeting, Newcastle
Gas from well
Acid gas water
nitrogen
NGL liquids
Sales Gas
Acid Gas Removal
Absorption processesPressure swing adsorption
Cryogenic distillationMembrane separation
Gas Dehydration
Absorption using glycolPressure swing adsorption
Mercury Removal
Adsorption
Nitrogen Rejection
Cryogenic distillationPressure swing adsorption
NGL Recovery
Turbo-expander and demethanizer
Gas Processing
• All the options for stranded gas involve some processing– Pipeline: All
– LNG: All
– CNG: All
– Gas to wire: acid gas removal, mercury removal
– Gas to liquid: acid gas removal, mercury removal
– Gas to solid: acid gas removal, mercury removal, NGL recovery.
21/5/2014 PIN meeting, Newcastle
Acid Gas Removal Using Amines
21/5/2014 PIN meeting, Newcastle
LP steam
Sour gas
Rich amine Le
an a
min
e
Sweet gas
Acid gas
Sweet gas
7000 kPa
600 kPa
Ab
sorb
er
Reg
ener
ato
r
Intensified Adsorber
• Gas field producing 1.4 billion cubic meters per year (at STP).
• Reduce the sulfur content to pipeline spec of 10 ppm(molar).
• Rich amine loading of 0.4 molCO2 per mol amine. 30 mass% amine solution.
• The ∆P in the column and rotating packed bed are the same.
• e = 97%, a = 250 m2 m-3
• Mass transfer coefficient (KGa) in the packed column is 0.02 s-1
• Mass transfer coefficient (KGa) in the RPB from the data of Jassim4
21/5/2014 PIN meeting, Newcastle
Intensified Adsorber
21/5/2014 PIN meeting, Newcastle
0
1
2
3
4
5
6
7
0
500
1000
1500
2000
2500
3000
3500
4000
0 1 2 3 4 5 6 7 8 9 10
Ro
tati
ng
Pa
ck
ed
Be
d P
ow
er
(MW
)
Ab
so
rbe
r V
olu
me
(m
3)
Acid gas content (mol%)
Rotating Packed Bed
• Capital cost savings have to offset the added operating cost of the RPB.
• Use higher concentration amine solutions in the RPB
Gas to Liquid (GTL)
21/5/2014 PIN meeting, Newcastle
Desulphurizednatural gas
Reformer
Syngas to dimethyl ether
Fischer Tropsch
Transported using LPG infrastructure
Transported using liquid fuel infrastructue
Syngas
Intensified GTL
21/5/2014 PIN meeting, Newcastle
micro channel reformer
fuel gas + air
hydrocarbon+ steam
LH mm»
combustion catalyst
reforming catalyst
micro channel Fischer Tropsch reactor
cooling water
syngas
FT catalyst
syngas
liquid fuels
steam
flue gas
• Intensification of the heat transfer process leads to compact reactors• Technology commercialized by Velocys and CompactGTL
Gas to Solids
21/5/2014 PIN meeting, Newcastle
LiquifiedNatural Gas
Compressed Natural Gas
Gas Hydrates
Temperature -162˚C ambient -10˚C
Pressure 1 bar 206 bar 1 bar
Gas content of 1 m3 at STP
600 m3 200m3 160m3
Gas Hydrate
Water molecules hydrogen bonded in a cage around a gas molecule
Gas to Solids
21/5/2014 PIN meeting, Newcastle
Water + surfactant
gas
10 ˚C, 60-90 bar
• Process is thermodynamically driven by pressure.
• Rate of hydrate formation is thought to be mass transfer controlled and could be intensified.
Windmeier and Oellrich5
Conclusions
21/5/2014 PIN meeting, Newcastle
• Utilizing stranded gas is a complex problem with many technical solutions
• Feasible options for stranded/associated gas need to be evaluated and niches for the application of Process Intensification identified.
• Process flow rates are large even for small fields.
• It is an area with potential for process intensification.
References
21/5/2014 PIN meeting, Newcastle
1. http://www.worldbank.org/en/topic/sustainabledevelopment
2. Wood D, Mokhatab S, 2008, “Gas monetiziation technologies remain tantalizingly on the brink”, World Oil, 229, 15
3. Khalilpour R, Karimi I A, 2012, “Evaluation of utilization alternatives for stranded natural gas”, Energy, 40, 317-328
4. Jassim M, Rochelle G, Eimer D, Ramshaw C, 2007, “Carbon Dioxide Adsorption and Desorption in Aqueous Monoethanolamine Solutions in a Rotating Packed Bed”, Ind.Eng.Chem.Res., 46, 2823-2833.
5. Windmeier C, Oellrich L R, 2014, “Visual observation of methane hydrate formation and dissociation process”, Chemical Engineering Science, 109, 75-81.
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