seminar on renewable energy technology implementation in...

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