Membrane Gas Separation Processes for CO2 Capture from ...€¦ · RWE Power Membrane Gas...

RWE Power

Membrane Gas Separation Processes for CO2 Capture

from Coal fired Power Plants

P. M. Follmann, C. Bayer, M. Wessling, T. Melin

RWTH AachenChemical Process Engineering

Some conversations …

Polymer membranes?

“I have heard they corrode …”

How much does it save?

How much can it achieve?

“I mean in %?”

Does it work?

One year of pilot plant operation in Borselen/NL• Water removal• Ash hick-up survived

New pilot plant studies running currently

“How much does it do in %?”

Definition of boundary conditions (I)

Power plant 560 kg/s flue gas

1 bar, 50°C, saturated in water

CO2 13.6%, N2 71.2%, O2 3.2%

Contaminants (SOx, NOx)

Power plant Capture Transport Storage

CO2 requirements?

CO2 concentration

Trace components

How much to be captured?

Definition of boundary conditions (II)

Delivery to pipeline at 130 bar and 30°C

Composition > 95.5 mole-% CO2

max. 4 mole-% of air gases (N2, Ar, O2)

2 scenarios for O2 contentHigh purity (only 100 ppm allowed)

Up to 4 mole-% O2

SOx and NOx (max. 0.5 mole-% in worst case)

Residual water content: not specified

Optimal capture rate: 90% assumed as optimal

Gas separation membranes

Polymeric membranes most suitable

CO2Permeance

CO2/N2Selectivity

CO2/O2Selectivity

CO2/SO2Selectivity

PPO 4.1 20 4.5 1

PEO 1.25 45 15 0.2

SPEEK 0.07 85 28 1

Permeance H2O >> permeance CO2

Mass transfer across membrane:

Pressure ratio across membrane:

ni = Qi AMem (xi pF - yi pP)

Φ = pF / pP

CO2 Removal

Permeate (CO2 rich)

Depleted flue gas

Flue gas

Driving force generation (I)

Feed compression and suction

Fluegas

Depleted flue gas

Compressor Permeate (CO2 rich)

Vacuum unit

Feed compression

Permeate (CO2 rich)

Depleted flue gas

Flue gas

Compressor

Low pressure at the permeate side

Flue gas Permeate (CO2 rich)

Vacuum unit

Depleted flue gas

Sweeping at the permeate side

Depleted flue gas

Flue gas Sweep gas

Permeate (CO2 rich)

Driving force generation (II)

Feed compression Area ↘ , energy ↗ No pressure limitation

Suction Area ↗ , energy ↘ Pressure limitation: ca. 200 mbar

Feed compression + suction Combines advantages of both technologies Most likely concept for driving force generation

Sweeping Only applicable in combination with suction Process steam no adequate sweeping agent

Membrane – A selective splitter

100

0.01

Ideal Highest Enrichment

100

100

0

Nonsense No Enrichment

99.99

100

70

30

Single-stage membrane system (PPO membrane)

0

300

600

900

1200

0.00 0.25 0.50 0.75 1.00

Recovered CO2 fraction of the 1st stage (PPO membrane)

Spec

ific

ener

gy d

eman

d of

the

1st s

tage

[k

J/kg

CO

2 rec

over

ed]

60%

50%40%

30%

3.0 bar

4.0 bar

5.0 bar

2.0 bar

60%

50% 40%

2bar

5 bar

Single-stage membrane system (PPO membrane)

0

300

600

900

1200

0.00 0.25 0.50 0.75 1.00

Recovered CO2 fraction of the 1st stage (PPO membrane)

Spec

ific

ener

gy d

eman

d of

the

1st s

tage

[k

J/kg

CO

2 rec

over

ed]

60%

50%40%

30%

3.0 bar

4.0 bar

5.0 bar

2.0 bar

Single-stage membrane system (PEO membrane)

0

300

600

900

1200

0.00 0.25 0.50 0.75 1.00

Recovered CO2 fraction of the 1st stage (PEO membrane)

Spec

ific

ener

gy d

eman

d of

the

1st s

tage

[k

J/kg

CO

2 rec

over

ed]

70%60% 50%

40%

30%

2.0 bar

3.0 bar

4.0 bar

5.0 bar

Summary single-stage membrane system

Trade-offs CO2 enrichment – CO2 recovery Energy requirement – membrane area

Further enrichment / purification by 2nd membrane stage Single-stage processes only applicable for enrichment

Further treatment to achieve low O2 and SO2 content O2 and SO2 enrich at the low pressure side

Economic framework

Reference power plant

Capital cost Euro/MWhel 20.50

Fuel cost Euro/MWhel 15.20

O&M cost Euro/MWhel 4.60

Membrane process

Compression Euro/kW 500

Vacuum Euro/kW 1000

Membrane Euro/m2 5 - 50

Specific CO2 avoidance cost = COECap - COERefCO2,Ref - CO2,Cap

Two-stage membrane processes without recycling

40-60% CO2

3-5 bar

Flue Gas

95% CO2

To pipeline

ExpanderTo

atmosphere

Expander

CO2 Compressor

0.2 bar

2-4 bar

0.2 bar1.0 bar

1st stage

2nd stage

130 bar

P

P


0

50

100

150

200

0.00 0.25 0.50 0.75 1.00

Recovered CO2 fraction of the 2 stage membrane process without recycling

Spec

ific

CO

2 avo

idan

ce c

osts

of t

he p

roce

ss

[Eur

o/to

n C

O2 av

oide

d]

PPO - PEO PEO - SPEEK

50 Euro/m2

Recovered CO2 fraction

Spec

ific

CO

2av

oida

nce

cost

[Eur

o/to

n C

O2

avoi

ded]


0

50

100

150

200

0.00 0.25 0.50 0.75 1.00


Spec

ific

CO

2 avo

idan

ce c

osts

of t

he p

roce

ss

[Eur

o/to

n C

O2 a

void

ed]


5 Euro/m2


Spec

ific

CO

2av

oida

nce

cost

[Eur

o/to

n C

O2

avoi

ded]

Two-stage membrane processes with recycling

40-60% CO2

3-5 bar

Flue Gas

95% CO2

To pipeline

ExpanderTo

atmosphere

Expander

CO2 Compressor

0.2 bar

2-4 bar

0.2 bar1.0 bar

1st stage

2nd stage

130 bar

Compressor

Recycle stream

2-4 bar

P

P


0

50

100

150

200

0.00 0.25 0.50 0.75 1.00

Recovered CO2 fraction of the two stage membrane process with recycling

Spe

cific

CO

2 avo

idan

ce c

osts

[Eur

o/to

n]

PEO - SPEEK

PPO - PEO

50 Euro/m2

Recovered CO2 fraction0.00 0.25 0.50 0.75 1.00

0

50

100

150

200

Spec

ific

CO

2av

oida

nce

cost

[Eur

o/to

n C

O2

avoi

ded]


0

50

100

150

200

0.00 0.25 0.50 0.75 1.00

Recovered CO2 fraction of the 2 stage membrane process with recycling

Spec

ific

CO

2 avo

idan

ce c

osts

of t

he p

roce

ss

[Eur

o/to

n C

O2 a

void

ed]

PEO - SPEEK

PPO - PEO

5 Euro/m2


0

50

100

150

200

Spec

ific

CO

2av

oida

nce

cost

[Eur

o/to

n C

O2

avoi

ded]

Summary and conclusions

Chemical durability of polymeric materials proven during one year piloting

Two stage membrane processes required + 90% CO2 recovery in conjunction with 95% purity

+ Simple integration in power plant process

+ Competitive economics compared to absorption process

+ Scalable modular membrane area

- CO2 product does not comply with strict purity requirements

- Specific energy requirement higher than chemical absorption

- Membrane cost have significant impact on process economics

RWE Power

Thank you very much for your attention

This study is part of the NanoGLOWA project (NMP3-CT-2007-026735), which has been financially supported by the EU Commission within the thematic priority NMP of the Sixth Framework Program.

Single-stage membrane system (PEO membrane)

0

300

600

900

1200

0.00 0.25 0.50 0.75 1.00

Recovered CO2 fraction of the 1st stage (PEO membrane)

Spec

ific

ener

gy d

eman

d of

the

1st s

tage

[k

J/kg

CO

2 rec

over

ed]

70%60% 50%

40%

30%

2.0 bar

3.0 bar

4.0 bar

5.0 bar


0

1000

2000

3000

4000

0.00 0.25 0.50 0.75 1.00


Spec

ific

ener

gy d

eman

d of

the

proc

ess

[kJ/

kg C

O2 r

ecov

ered

]




0

1000

2000

3000

4000

0.00 0.25 0.50 0.75 1.00

Recovered CO2 fraction of the 2 stage membrane process with recycling

Spec

ific

ener

gy d

eman

d of

the

proc

ess

[kJ/

kg C

O2 r

ecov

ered

]



Two-stage membrane processes with recycle

90% CO2 recovery: PPO / PEO system

Feed pres.1st/2nd stage

Energy[kJ/kg]

Area [105 m2]

O2[%]

SO2[ppm]

3 bar / 4 bar 1910 7 1.8 510

4 bar / 4bar 1940 5 1.8 510

Feed pres.1st/2nd stage

Energy[kJ/kg]

Area [106 m2]

O2[%]

SO2[ppm]

2 bar / 4 bar 1350 8 1.2 520

3 bar / 4bar 1400 5.1 1.2 520

90% CO2 recovery: PEO / SPEEK system

Membrane Gas Separation Processes for CO2 Capture from ...€¦ · RWE Power Membrane Gas...

Documents

Transcript of Membrane Gas Separation Processes for CO2 Capture from ...€¦ · RWE Power Membrane Gas...