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2. Juni 2009

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Overview on 1st and 2nd generationcoal-fired membrane power plants(with and without turbo machinery

in the membrane environment)

L. Blum, E. Riensche, J. Nazarko, R. Menzer, D. StoltenJülich Forschungszentrum, D-52425 Jülich

Institute for Energy Research – Fuel Cells (IEF-3)

Fourth International Conference on Clean Coal Technologies

CCT2009- Dresden, Germany 18-21 May 2009 -

Bild 2Institute of Energy Research – Fuel Cells (IEF-3)

• A membrane application of today: CO2 separation from natural gas

• Coal-fired membrane power plants (MPPs) – Classification

• Several concepts in development - 1st generation MPPs:Compressors required for membrane operation

• “IG-SWEEP-JÜL” - Opening the road to 2nd generation MPPsw/o additional turbo machinery in the membrane environmentDriving force by dilution of H2 into a sweep gas (in modified IGCC)

Contents


Arian Nijmeijer / SHELLOne of the industrial partners of FZJ in the HGF Alliance MEM-BRAIN

CO2 Removal from Natural Gas by Polymer Membranes

Natural gas pressure~ 100 bar !!!


Example:NG 100 barCO2 10 mol%

CO2 Membrane environment

CO2

Retentate

Permeate 1 bar “Pure“ CO2

Natural “driving force“ for permeation

pCO2 = 10 bar

CO2 Removal from Natural Gas (CH4 )

p ~ pCO2 = 1 bar

no compressor

no vacuum pump

No el. energy is needed


Natural Driving Force

in

Membrane Power Plants?


Flue gas70 °C1 bar

“Pure“CO2Coal

Airλ~1

Basicsteam

power plant


N2CO2 N2

Retentate

Vacuum pump1 barPermeate

Transport lawfor polymer and porous ceramic membranes:Local CO2 permeation flux density= CO2 permeability * ΔpCO2 (Feed side - Permeate side)

Post-combustion: Membrane + Vacuum Pump

30 mbar

140 mbar

CO2 14 mol%

El. Power:106 kWh/t CO2 separatedforCO2 purity: 80 mol%Vacuum: 30 mbar(PRO/II simulation)

“Driving force“ for permeationCO2 liquefaction: ~100-130 kWh/t CO2


The Idea of a Sweep Gas: Driving Force by Dilution !?


CO2

RetentatepCO2 = 140 mbar

no compressor

no vacuum pump

Flue gas

Sweep gasCO2

pCO2 ~ 50 mbar 0 mbar

Sweep gas + CO2

butCO2 dilution into a sweep gas produces impure CO2 again !!!


besides post-combustion:

Driving Force

by Dilution into a Sweep Gas

in

Membrane Power Plants?


Coal-Fired Membrane Power Plants

Classification


3 Capture Principles – 4 Membrane Gas Separation Classes

Flue gasPost-combustion

Combustion with airCO2 capture from FG

OxyfuelO2 separation from air

Combustion with O2Cooling by CO2 recycling

Shifted coal gas(pressurized)

Pre-combustion/H2 or /CO2

Partial oxidation (gasific.)CO shift to CO2

H2 or CO2 separationH2 combustionH2 CO2

CO2 H2

Air

N2 O2

N2 CO2

Coal + O2

CO2Conden-sation

H2O + CO2 + Impurities

Special polymer membranes:The larger molecule permeates!

+ O2 (N2 )

from plant

+ ImpuritiesN2 (O2 )

from membrane


Separated Gas Components: Pure or DilutedFlue gasPost-combustion

Oxyfuel

Shifted coal gas

H2 CO2

CO2 H2

Air

N2 O2

N2 CO2CO2pureCO2

diluted

O2pure

O2diluted

Pre-combustion / H2 -sepH2

pure

Pre-combustion / CO2 -sep

H2diluted

CO2pure

CO2diluted

Dilution of CO2impure CO2 again

no chance forsuccessful sweep !!!

Dilution of O2 or H22 Chances for

successful sweep !!!


3 Capture Principles – 3 Technology Platforms6 Capture classes are of interest for MPPs

not possible 2SPP / Oxyfuel1

SPP / Post-comb.

IGCC not possible 4IGCC/ Total-oxyfuel3

IGCC / Post-comb.

IGCC+Shift/H2GT 5 and 6IGCC+… / Pre-c.not

the best solutionnot

the best solution

Pre-comb/H2 or /CO2 Oxyfuel Post-combustion

SPP(Steam Power Plant)

combustiongasification

combustion (atm. )Coal

CoalO2 Steam

combustionCO shiftgasificationCoal

O2 SteamExcesssteam

IGCC: Integrated Gasification Combined Cycle

CO2 , H2

CO, H2Air or O2

Air

Air or O2


Class 2

SPP / Oxyfuel


3 Measures for Driving Force in the Membrane

1

Feed side (air):Compressor / Expander

Permeate side (O2 ):Vacuum pump

Permeate side:Sweep gas = Hot recycled flue gas

1

3

“OTM-Clean”/Pressurized

“OXYVAC-JÜL”

“OXYCOAL-AC”

2

Pure O2

Pure O2

Diluted O2


“OXYVAC-JÜL“: Permeate Compression (Vacuum Pump)Basic variant: Some NG is burned for final air preheating

Source:Meulenberg, Baumann, Blum, Riensche: Deutsche Patentanmeldung 10 2007 056 841.1 (PT 1.2366) 23.11.2007

Air Depletedair

NG

Recuperativeheat

CO2

H2 O

CO2 Recycling

Coal

Vacuumpump

MIEC Unit

Steamgenerator

O2

1 bar

50 mbar

~800°C

O2

~750°C

pO2Feed 200 100 mbarpO2Perm 50 50 mbar

pO2Feed /pO2Perm=4:1 2:1

CO2Com-press.

Oxyfuel Unit

O2

~200°C50 mbar 1 bar 1 bar

Δη = about -10 %pincl. liquefaction

Oxyfuel unit asin conventionalseparation plant

Low pressure differences inHT air preheater & HT membrane MIEC(Mixed Ionic Electronic Conductor)

PRO/II simulation:


“OXYCOAL-AC“: Sweep Gas & Compression

Flue gas (CO2 , H2 O, O2 , N2 )

Coal

20 barAir

1 barH2 O

CO2O2 850°C500°C

750°C

800°C Clea-ning

850°C

Steamgenerator

Advantage: High driving forces

Feed

PermpO2 ~200 ~30 mbarpO2 4000 2000 mbar

pO2 /pO2 20:1 70:1Feed Perm Theoretical case: Sweep w/o compression

O2 : ~200 mbar in air~200 mbar in sweep gas Driving force missing

Reason: Air ratio low (λ~1) in SPPssmall flow rates of cooling mediasmall flow rates for sweep gases

20 bar

High temperaturerecuperator

MIEC

1 bar

Δη = about –9 %pincl. liquefaction[Beggel (RWTH) 2008]


Class 4

IGCC / Total-oxyfuel

For O2 membranes

IGCCs have a potential for large sweep gas streams.

Concepts may be developed in future.


Class 5

IGCC+Shift/H2GT / Pre-comb./H2-sep


Pre-combustion: Pure H2 is Separated - Combined with RecompressionStandard membrane concept

Gasif. Clean. C

ASU

Steam line

Pressure level of all process gases: 25 barexcept H2 permeate

CoalCO2

Membrane environment

GT

ST

HRSG

G G~1200°C

λ~2.5

H2

H2

Compressed air

press. N2

25 bar

O2 incl.CO Shift

C

0.5 bar

Excess airO2 , N2

Steam

H2 Recompression

Flue gasH2 O, N2 , O2

CO+H2O=CO2+H2

Energetic losses• Excess steam for shift• H2 recompression !!!

25 bar

CO2 , H2 ,Impur.

Press. CO2 (H2 ),Impurities

Δη ∼

-10 %-points[Göttlicher,VDI-Ber. 421, 1999]

!!!

for sweeptoo much O2


2nd GENERATION

MEMBRANE PP CONCEPT:

WITHOUT ADDITIONAL TURBO MACHINERY

IN THE MEMBRANE ENVIRONMENT


Membrane Operation w/o Energy SupplyH2 dilution by sweep gas w/o O2


H2

CO2 + H2 CO2

Sweep gas= Recycled flue gas

no compressor

no vacuum pump

“IG-SWEEP-JÜL“

N2 + H2Shifted coal gas

Sweep gas + permeateto GT burner

N2

Sources:Menzer, Riensche, Peters, Blum, Scherer: Deutsche Patentanmeldung DE 10 2008 01 17 71.4, 26.02.2008Riensche, Menzer, Blum: Deutsche Patentanmeldung DE 10 2008 04 80 62.2, 19.09.2008


IGCC Modified to “IG-SWEEP-JÜL“Stoichiometric combustion & Recycling of the flue gas: N2 (O2 -free)

Gasif. Clean. C

CC

ASU

Steam line

Pressure level of all process gases: 25 bar

Coal

CO2

Stoich. Air: O2 , N2


GT

ST

HRSG

G G

Flue gas:N2

H2 O~1200°C

λ=1 no O2

Flue gasrecycling: N2

H2

CO2 , H2 Press. CO2

N2 , H2

Compressed air

~400°C

Press. N2

25 bar

O2 incl.CO shiftPress. N2

Steam

Porousceramic membrane

N2 /H2 ~6 mol/mol

N2 /H2 ~4 mol/mol

PRO/II simulation

Sweep gas 1: N2

Sweep gas 2: N2


Membrane in “IGSWEEP-JÜL“ - H2 Partial Pressure Profiles

Feed side

Permeate side

5 bar

25 bar

00

H2 Separation degree

H2Partial

pressure

50%

15 bar

98%

High ratio:Sweep gas / permeated H2 ~ 4:1 mol/mol !!!

Highdrivingforces

H2 , CO2

4N2 +H2Sweep gas

Highest H2 separation degrees possible !!!

Sweep gas= 4N2 (no H2 !!!)


• “Natural driving forces” for permeation do not exist in MPPs,if pure gas components are separated (CO2 , O2 , H2 ):Compressors consume much energy (comparable to CO2 liquefaction).

• “IG-SWEEP-JÜL” opens a new PP route of 2nd generation MPPswith “energy-free” dilution of permeating H2 (or O2 ) into a sweep gas.

• Large sweep gas streams are required and could be foundin IGCC modifications w/o significant additional energy demand.

• The total efficiency penalty may approach 5 %-points (after optimization):capture ~1 %p (parasitic losses)liquefaction 4 %p

Conclusions


Coal power plants: ~40% of anthropogenic CO2 emissions !!!We need: worldwide acceptable CCS

“energy-free” captureoptimal membrane integration

THANK YOU FOR YOUR ATTENTION


Appendix


What is an Acceptable Capture Technology?

High CO2 purity! In discussion:CO2 >80 mol% ???CO2 >90 mol% (work hypothesis here)CO2 >95 mol% (MEA as benchmark)

1

Low efficiency losses! Hypothesis for successful CCS:All nations of the world may accept year by year

10% more coal input or10% loss in power production, but not more.

η ~ 50% for modern PPs

Acceptable Δη: -5 %-points (CCS)Compression: Δη

= -3 to -4 %-points [literature]

For capture: Acceptable Δη: -1 to -2 %-points

2


Fossil-Fired Power Plants w/o Capture

SPP pressurizednot realized

Coal combustionpressurized

GTST

IGCCIntegrated Gasif. CC

only a few exist

combustiongasificationCoalCO, H2 pressurized

GTST

η

high ~50%O2 Steam Air

not realized in large scale

NGCCNG Combined Cycle

NG Boileronly a few exist

Natural gas combustionpressurized

GTST

η

high ~58%

Natural gascombustionatmospheric ST

atmosphericSPP

Steam Power Plantη

~45%Coalcombustion

ST

mean η

world ~30%

Oil Fired PPs only a few exist

GT: Gas TurbineST: Steam Turbine



CO2

Retentatep = 1 barpCO2 = 140 mbar ~50 mbar

The Idea of a Sweep Gas for CO2 Dilution

no compressor

no vacuum pump

Flue gas

Sweep gas w/o CO2CO2

pCO2 ~ 50 mbar 0 mbar

Sweep gas + CO2

A tricky solution, if• sweep gas available (p=1 bar or



CO2

Retentatep = 1 barpCO2 = 140 mbar

But How to Remove CO2 from Atmospheric Flue Gas ???

no compressor

no vacuum pump

AirpCO2 =0.3 mbar Air (O2 , N2 )

CO2 dilution in air ???General question in membrane plant development:Are there other ways besides energy consuming compressionto realize a positive “driving force“ ???

Coal

Airλ~1

Basicsteam

power plant Fluegas


Feed (Flue gas)

Permeate

140 mbar

30 mbar

1 bar

00

CO2 separation degree

CO2partial

pressure

50% 100%

Driving force for CO2 decreases, but not for N2

Driving forcemembrane inlet110 mbar

Driving forcemembrane outlet40 mbar

Low Driving Force for Permeation even at Membrane Inlet

Feed pressure 1 barPermeate pressure 30 mbar


CO2 Impurities – Strongly Important in a Large Oxyfuel Plant

Clea-ning

Flue gasCO2 , H2 O, O2 , N2

CoalAir

1 barH2 O

CO2to compr.O2 (N2 )

cold

N2

Expected CO2 purity: about 80-85 mol%Compression Pipeline

Source: Oxyfuel Conference, Cottbus, April 2007

Steamgenerator

ASU

O2 content: 4-8 mol% Air leackage

N2 +Ar: 5 mol%O2 : 95 mol%

cold

RemarkN2 < 1 mol%

is target for an excellent O2 membrane[MEMBRAIN proposal 2007]


“OTM-clean/Pressurized“ with Cold Flue Gas RecyclingAir Preheating in Steam Generator

Feed

PermpO2 1 1 barpO2 4 2 bar

pO2 /pO2 4:1 2:1Feed Perm

Coal

20 bar

Air Steamgenerator

1 bar

CO2

800°C

Clea-ning

Flue gasCO2 , H2 O, O2 , N2

H2 O

1 bar

O2O2

Disadvantage: Low driving forces

OTM-clean cold


IGCC/Total-Oxyfuel: O2 Gasification & O2 Combustion Advantage: 1-stage capture w/o CO shift

“Small“ASU

Steam line

Pressure level of all process gases: 25 bar

Coal

Flue gasCO2 , H2 O

Steam

Coal gasCO, H2

O2

O2

Air

“Large“ASU

Vision for Membrane PPsFor O2 membranes

large CO2 sweep gas streamswould be available (pressurized):

pO2(Feed) / pO2(Permeate)= 21/12 ~ 2:1 !!!

[Göttlicher, VDI-Ber. 421, 1999]

Source: after SIEMENS, Pictures of the Future, Spring 2008

Air

Gasification

CombinedCycle

with large (!!!)FG recycle

stream


Transport Mechanisms of Inorganic Membranes“Dense“ membranes can perfectly select O2 and H2 electrochemically

O2-

2 e-

H

Multi-layer and/or specific adsorption:

carbons, zeolites, amorphous SiO2

MolecularSieves:

zeolite, carbons, amorphous SiO2

Ionic transport(solid electrolytes):O2-, H+ in perovskites

Atomic transport of H:metals, e.g. Ag/Pd, Nb, V, TaAfter: Caro

(Univ. Hannover)2007

MIEC: MixedIonic ElectronicConductor,O2 /N2 selectivity~100,000:1 !!!(theoretically)

800 – 1000°C

150 – 400°C

MPEC: Mixed Protonic Electronic Conductor

MPEC500-800°C

Slide Number 1Slide Number 2CO2 Removal from Natural Gas by Polymer Membranes�Slide Number 4Slide Number 5Slide Number 6Slide Number 7Slide Number 8Slide Number 9Slide Number 10Slide Number 11Slide Number 12Slide Number 13Slide Number 14Slide Number 15Slide Number 16Slide Number 17Slide Number 18Slide Number 19Slide Number 20Slide Number 21Slide Number 22Slide Number 23Slide Number 24Slide Number 25Slide Number 26Slide Number 27Slide Number 28Slide Number 29Slide Number 30Slide Number 31Slide Number 32Slide Number 33Slide Number 34Slide Number 35

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