Seminar on Renewable Energy Technology implementation in Thailand
Experience transfer from Europe
co-organised by the Delegation of the European Union to Thailand and
the Department of Alternative Energy Development and Efficiency, Ministry of Energy
Use of CBG as replacement for CNG – Technology and
Standards
Anders Ek / Asia Biogas
2012.10.05
Outline
• Biogas vs. Biomethane
• Upgrading technologies
• Upgrading units in the world
• Vehicle fuel/grid injection standards
• Case studies
• Thailand Outlook
Biogas
• Produced from anaerobic digestion of
organic material.
• Methane (CH4) 50 – 80 %
• Carbon dioxide (CO2) 20 – 50 %
• Hydrogen Sulfide (H2S) x00 – x000 ppm
• Water (H2O) Saturated
• Siloxanes, Ammonia (NH3), Nitrogen (N2)
Biomethane
• Upgraded biogas suitable for CNG/NGV
vehicles or for gas grid injection.
• Methane (CH4) 95 – 99 %
• Carbon dioxide (CO2) 1 – 5 %
• Hydrogen Sulfide (H2S)
• Water (H2O)
• Siloxanes, Ammonia (NH3), Nitrogen (N2)
Upgrading
• Principles of biogas upgrading (CO2
removal):
• Adsorption: Pressure Swing Adsorption
• Absorption: Water
Polyethylene glycol
Amines
• Permeation: Membrane separation
• Cryogenic: Condensation of gases
Upgrading
Technology Ad/absorption media Regeneration
method
Working
pressure
(bar)
Pressure Swing
Adsorption (PSA)
Dry medium, e.g.
Activated Carbon
Depressurisation 4 – 7
Water Scrubber Water Depressurisation +
air stripping, or
None
5 – 10
Amine Scrubber Amine solvent, e.g.
Mono Ethanol Amine
(MEA)
Heat Ambient
Organic solvents Ethers of polyethylene
glycol, e.g. Selexol,
Genosorb
Depressurisation +
air stripping
7 – 8
PSA
• CO2 adsorbed on surface under pressure
(N2 and O2 to some extent)
• Activated Carbon or Zeolites
• ≥ 4 adsorber columns in parallel
• Regeneration though sequential pressure
decrease (“pressure swing”)
Sources: BiogasMax, IEA
PSA
• H2S adsorbes irreversibly
• H2O can destroy medium
• Exhaust gas: Sulfur free, >1 % CH4
• Biomethane >96 % CH4
• Remove H2S, Siloxanes, Organic Solvents
before PSA.
• Treat exhaust gas.
Sources: BiogasMax, IEA
PSA
Source: ISET, 2009
Water Scrubber__
• Counter flow of liquid and gas in packed
column, under pressure
• CO2 solubilised in water (low temperature)
• Water can be recycled or used one time
• Regeneration through release of pressure
and air stripping
• H2S and NH3 also removed
• Siloxanes removed to some extent
Sources: BiogasMax, IEA
Water Scrubber__
• Exhaust gas: Sulfur, >0.5 % CH4
• Biomethane >97 % CH4
• Remove H2S and Siloxanes if very high
concentrations in raw gas (or a sulfur free
exhaust gas is required)
• Treat exhaust gas for CH4?
• No separation of N2 or O2
Sources: BiogasMax, IEA
Water Scrubber__
Source: ISET, 2009
Amine Scrubber__
• Counter flow of liquid and gas in packed
column, under atmospheric pressure
• CO2 is both absorbed in and reacts
chemically to the amine liquid
• Mono- or Di-ethanol-amine (MEA/DMEA)
• Regeneration through heating (120-160 C,
can be modified to <100 C)
• Some amine liquid lost
• Very low CH4 loss (<0.1 %)
Sources: BiogasMax, IEA
Amine Scrubber__
• H2S binds stronger than CH4 (higher
temperature needed for regeneration)
• >99 % CH4
• Remove H2S, Siloxanes, Organic solvents
before Amine scrubber
• Cannot remove N2, O2
• Exhaust gas: Sulfur free, almost CH4 free
• No exhaust gas treatment needed.
Sources: BiogasMax, IEA
Source: ISET, 2009
Upgrading
Pressure Swing
Adsorption (PSA)
Water
Scrubber
Amine
Scrubber
Electricity
(kWh/Nm3 biogas) 0.20 – 0.25 0.20 – 0.25 0.10 – 0.15
Heat
(C) No No
120 – 160
(<100)
Working pressure
(bar) 4 – 7 5 – 10 Ambient
Methane loss
(% of total CH4) 1.0 – 6 0.5 – 2.0 <0.10
Methane content
(% in upgraded gas) >96 97 – 99 >99
Sources: IEA, Fraunhofer/IWES
Upgrading
• How to choose upgrading technology
• Questions to consider
• Examples
Upgrading
1. Ample/cheap process water available?
2. Waste heat available?
3. H2S content?
4. Siloxane content?
5. Required CH4 content of the biomethane?
6. Requirements on CH4 loss/capture rate?
7. End-use? Pipeline / vehicle fuel / other?
Upgrading
• Example 1: Upgrade biogas at a
wastewater treatment plant
– Ample supply of 'free' process water (treated
effluent)
– Beneficial for water scrubber, as you will have
low operating cost.
Upgrading
• Example 2: Very high requirements on
1. Methane content
2. Methane capture rate
• Probably suitable for Amine.
– Capture rate >99.9 %
– Biomethane of >99 % CH4
• Investment cost?
• Free or cheap waste heat?
Upgrading
• Example 3:
– Expensive process water, or no water
– No free or cheap waste heat
• Consider PSA?
• Methane capture rates?
Upgrading
Overview of upgrading units in the world
– Source of gas
– Location
– Technology
– End use
Biogas vs. LFG__
Nu
mb
er
of u
nits
Nm
3 b
ioga
s /
ho
ur
Undefined
LFG
Biogas
0
20
40
60
80
100
120
140
160
180
200
Units
Undefined
LFG
Biogas
0
50,000
100,000
150,000
200,000
CapacityData source: IEA, 2012.05.11, http://www.iea-biogas.net/_content/plant-list/plant-list.html
Location
Nu
mb
er
of u
nits
Nm
3 b
ioga
s /
ho
ur
AsiaN America
Other EU
Germany
Sweden
0
20
40
60
80
100
120
140
160
180
200
Units
Asia
N America
Other EU
Germany
Sweden
0
50,000
100,000
150,000
200,000
CapacityData source: IEA, 2012.05.11, http://www.iea-biogas.net/_content/plant-list/plant-list.html
Technology
Other
Membrane
Chemical
PSA
Water
0
20
40
60
80
100
120
140
160
180
200
Units
Other
Membrane
Chemical
PSA
Water
0
50,000
100,000
150,000
200,000
Capacity
Nu
mb
er
of u
nits
Nm
3 b
ioga
s /
ho
ur
Data source: IEA, 2012.05.11, http://www.iea-biogas.net/_content/plant-list/plant-list.html
Grid vs. Vehicle__
Nu
mb
er
of u
nits
Nm
3 b
ioga
s /
ho
ur
Undefined
Vehicle
Grid
0
20
40
60
80
100
120
140
160
180
200
Units
Undefined
Vehicle
Grid
0
50,000
100,000
150,000
200,000
CapacityData source: IEA, 2012.05.11, http://www.iea-biogas.net/_content/plant-list/plant-list.html
Standards
• Vehicle fuel/grid injection standards in
different countries in Europe:
– Sweden
– Germany (low/high grade)
– France (low/high grade)
– Switzerland (low/high grade)
– Austria
– The Netherlands
– Belgium
– Czech Republic Sources: BiogasMax, IEA, SGC
Standards
• Early adopters:
– The Netherlands (1987, LFG, water scrubber)
– Switzerland (1995, Biogas, PSA)
– Sweden (1997, Biogas, water scrubber)
• End of 1999:
– 10 upgrading units (4,300 Nm3 Biogas/hour)
• May 2012:
– 162 upgrading units
(127,785 Nm3 Biogas/hour)
Data source: IEA, 2012.05.11, http://www.iea-biogas.net/_content/plant-list/plant-list.html
Standards
• Grid injection of LFG:
– Only practiced in The Netherlands
– Allowed in France, not implemented
– Forbidden in Switzerland, Austria, Germany
• Sweden:
– Vehicle fuel focus, due to low coverage of
natural gas grid.
Sources: BiogasMax, IEA, SGC
Standards
Au
stria
Fra
nc
e*
Cze
ch
Ge
rma
ny*
Neth
erla
nd
s
Sw
ed
en
Sw
itze
rlan
d*
CH4 %vol ≥96 ≥86 ≥95 >85 ≥96 ≥96
CO2 %vol ≤3 ≤2.5 ≤5 <6 ≤6 ≤3 ≤6
O2 %vol ≤0.5 ≤0.01 ≤0.5 ≤0.5 ≤1 ≤0.5
Higher
Wobbe
index
MJ/Nm3 47.7 –
56.5
48.24 –
56.52
46.1 –
56.5
43.46 –
44.41
44.7 –
46.4
S mg/Nm3 ≤10 ≤30 ≤30 ≤30 ≤45 ≤23 ≤30
Siloxane mg Si/Nm3 ≤4 ≤6 ≤6.2
NH3 mg/Nm3
Tech.
Clean ≤3 No ≤3 ≤20 ≤20
*) refers to standard for high gas quality
Sources: BiogasMax, IEA, SGC
Standards
• Ongoing work:
– for European standard on Biomethane, in
– CEN/TC408 ”Project Committee –
Biomethane for use in transport and injection
in natural gas pipelines”.
– Swedish vehicle fuel standard
– etc
Sources: BiogasMax, IEA, SGC
Standards
• Expected focus:
– Match local NG grid standards
– Siloxanes (undiagnosed problems in NGVs?)
from LFG, sewage sludge
– Oil (compressors!)
– Water
– Halogenated hydrocarbons
– Sulfur (SOx inhibit catalysts)
Sources: BiogasMax, IEA, SGC
Germany
• Laws and regulations for:
– Grid connection
– Methane loss
Case studies
• Examples in Europe
– Local biomethane grid
– Local raw gas grid
– NG grid injection
– Biogas train
• Examples in South Korea
Thailand Outlook___
• NG infrastructure
• NGV/CNG vehicles
• Example calculations
Future Outlook__
• Emerging technologies
• LBG – LNG synergies
• Increasing prices for CNG
– CBG/LBG competitive.
Asia Biogas
• Asia Biogas Group:
– Biogas
– Gasification
– Biomass
– Project development
– EPC
– BOOT
• Projects in:
– Thailand
– Philippines
– Indonesia
– Malaysia
www.asiabiogas.com