CO2

CAPTURE ACTIVITIES IN ICB-CSIC:

Chemical-Looping Combustion and Oxy-fuel

A. Abad, F. García-Labiano, L. F. de Diego, P. Gayán,J. Adánez

Instituto

de Carboquímica

(ICB-CSIC), Dept. of Energy & Environment, Combustion and Gasification Group,

Zaragoza, Spain

Ponferrada,

29th-30st

November

2011

abad@icb.csic.es

63rd IEA Fluidized Bed Conversion Meeting

CO2

CAPTURE ACTIVITIES IN ICB-CSIC

► Chemical Looping Combustion

► Oxy-fuel Combustion in Fluidized Beds

A. Gasification of coal in the fuel-reactor

B. CLOU: Chemical-Looping with Oxygen Uncoupling

CLC with solid fuels

Coal

CO2

+ H2

ON2

(+O2

)

Mex

Oy

H2

O(l)

CO2

Air Reactor

FuelReactor

Mex

Oy-1

Condenser

Air

CLC: Direct coal feeding to the fuel-reactor

H2

O(v)and/or

CO2AshAsh

Two options to evaluate

CO2

A. Gasification of coal in the fuel-reactor

Coal

H2O and/or CO2

H2O

COH2

H2O

Char

Volatiles

Oxygen-Carrier

CO2 H2O

First, coal is dried and devolatized

Remaining solid char is gasified

to give gaseous

H2

and CO

Volatiles and Gasification Products react with oxygen-carrier as a gas-solid reaction

►

Coal H2

O + Volatile matter + Char

►

Char + H2

O H2

+ CO

►

Char + CO2

2 CO

►

+ n Mex

Oy

CO2

+ H2

O + n Mex

Oy-1

Volatile matterH2

+ CO

H2

OCO2

CLC with solid fuels

B. CLOU(*): Chemical-Looping with Oxygen Uncoupling

Here, coal is also dried and devolatized

But the oxygen-carrier is able to release gaseous OXYGEN (O2

)

Volatiles and Char react with OXYGEN (O2

) as in common combustion with air

►

Coal H2

O + Volatile matter + Char

►

+ O2 CO2

+ H2

OVolatile matter

Char

Coal

O2

CO2 H2O

Volatiles

CO2

CO2

Char

CO2 H2O

Oxygen-Carrier

►

2 Mex

Oy

2 Mex

Oy-1

+ O2

(*)

T. Mattisson, A. Lyngfelt, H. Leion. Int J Greenhouse Gas Control, 2009, 3, 11-19

CLC with solid fuels

Key properties of Oxygen-Carriers for CLC with coal

Gasification in the fuel-reactor

•

Natural ores

•

Waste materials

CLOU

Reactivity is not a key factor, because gasification is a slow reaction

Low cost material are very interesting

Temperature (ºC)600 800 1000 1200

Part

ial p

ress

ure

of O

2 (at

m)

0.01

0.1

1

CuO/Cu2 OMn2 O3 /Mn3 O4

Co3 O4 /CoO

Appropriate thermodynamic for oxygen uncoupling at temperature of interest

CLC with solid fuels

1 MWth

CFB - CFB

Coal

Ilmenite

Operative in 2011

Damrmstadt UniversityOf Technology

GERMANY

Power

Configuration

Fuel

Oxygen carrier

Operation time

Location

COUNTRY

3 MWth

CFB - CFB

Coal

CaSO4

Operative in 2011

ALSTOM(Windsor)

USA

Power

Configuration

Fuel

Oxygen carrier

Operation time

Location

COUNTRY

CLC with solid fuels

Adánez et al. Progress in Chemical-Looping Combustion and Reforming Technologies. Progess in Energy and Combustion Science. 2011

CLC with solid fuels

projects

Emission Free Chemical Looping Coal Combustion Process(ECLAIR)

Captura de CO2 en la combustion de carbón con transportadores solidos de oxigenoPlan Nacional de I+D+I (ENE2010-19550)

Demonstration of the CLC technology with coal at a scale of 1 MWth

To develop low cost oxygen carriers suitable for CLC with solid fuels

CSIC-ICB-s1 rig for CLC and CLOU with coalConfigurationConfiguration CLCCLC CLOUCLOU

OxygenOxygen--CarrierCarrier IlmeniteIlmenite Cu60MgAlCu60MgAl

Preparation method Natural ore Spray-drying

Oxygen capacity (%) 4 6

Particle size (m) 150-300 100-200

Solids in Fuel-reactor ~ 800 g ~ 450 g

Total solids 3500 g 2000 g

Fuel (200-300 m) “El Cerrejón”

coal “El Cerrejón”

coal

Fluidization gas FR H2

O N2

/CO2

1.-

Fuel Reactor (i.d. 5 cm)Bed height: 20 cm

2.-

Loop seal 3.-

Air Reactor (i.d. 8 cm)Bed height: 10 cm

4.-

Riser5.-

Cyclone

6.-

Diverting solids valve7.-

Control solids valve8.-

Coal9.-

Screw feeders10.-

Furnaces11.-

Vaporizer12.-

Tar recovery

Experimental CLC

H2O CO2 N2N2Air

Sec.Air

7

82

4

5

6

10

3

1

9

1110

AIR REACTOR

FUEL REACTOR

H2O CO2 N2N2Air

Sec.Air

7

82

4

5

6

10

3

1

9

1110

AIR REACTOR

FUEL REACTOR

Gas analysisO2, CO, CO2

Tar analysisGC – MS

Stack

StackAir

Stack

Gascombustion

Tar recovery

10

Gas analysisCH4, CO2, CO, H2

12

Coal or biomass

H2O CO2 N2N2Air

Sec.Air

7

82

4

5

6

10

3

1

9

1110

AIR REACTOR

FUEL REACTOR

H2O CO2 N2N2Air

Sec.Air

7

82

4

5

6

10

3

1

9

1110

AIR REACTOR

FUEL REACTOR

Gas analysisO2, CO, CO2

Tar analysisGC – MS

Stack

StackAir

Stack

Gascombustion

Tar recovery

10

Gas analysisCH4, CO2, CO, H2

12

Coal or biomass

Experimental planning

Experimental CLC

CLC CLOU

Temperature

in FR (ºC) 880-950 900-960

Coal

Feed

(g/h) 42 112

Fuel Power

(Wth

) 250 700

Solids

Inventory

(kg/MWth

)3200 600

Solids

Flow

(kg/h) 3.5 4.5

tres

Solids

in FR (min) 13 6

Fluidization

gas H2

O N2

Performance evaluation

Carbon capture efficiency

Char conversion

Combustion efficiency in the Fuel Reactor

Carbon converted to gas in the FREff.CC =Carbon introduced

Ox. supplied by oxygen carrierEff.Comb FR=Ox. demand coal converted in fuel reactor

charC in char converted in the FRX =

C in char introduced

COAL

CO2

H2

O

FuelReactor

Un-burnt products

(CH4

+CO+H2

)

Air

CO2

CHAR

Eff.Comb

FR

Eff.CC

N2

AirReactor

Experimental CLC

Coal conversion

Effect of the Fuel Reactor Temperature

Con

cent

ratio

n,dr

y, N

2 fre

e (%

)

0

20

40

60

80

Tem

pera

ture

(ºC

)

800

840

880

920

960

T

CO2

CH4

H2CO

time (h)0 1 2 3 4 5

Con

cent

ratio

n (%

)

0369

121518

AIR REACTOR

O2

FUEL REACTOR

CO2

Results CLCOC: Ilmenite

•

Smooth operation

•

Full combustion was not reached

•

No tars nor other hydrocarbon that CH4

►

Un-burnt gases only coming from volatiles

Temperature (ºC)860 880 900 920 940 960

Cha

r con

vers

ion

(-)0.0

0.2

0.4

0.6

0.8

1.0

Temperature (ºC)860 880 900 920 940 960

Effic

ienc

y (%

)

0

20

40

60

80

100

Results CLCOC: Ilmenite

► Carbon Capture & Combustion Efficiency

► Char conversion

Carbon Capture Eff.

Combustion Eff.

Effect of the Fuel Reactor Temperature

Carbon capture

increases due to enhanced gasification rate

High temperature (1000 ºC) to get high char conversion and carbon capture

Combustion efficiency: Volatile matter is better burnt at high temperature

3200 kg/MWth

tres

= 13 min

Effect of the Fuel Reactor Temperature

Results CLOUOC: Cu60AlMg

•

Smooth operation

•

Full combustion was always reached

•

Very low concentration of CO2

from the air reactor

860880900920940960980

0

10

20

30

40

50

time (min)0 50 100 150 200 250 300

860

880

900

920

940

0

10

20

FR

AR

T

T

CO2

O2

CO2

O2

Tem

pera

ture

(ºC

)

CO

2or

O2

(vol

.%)

►

Oxygen (O2

) appears together combustion gases at equilibrium for CuO/Cu2

O

Temperature (ºC)900 920 940 960

Cha

r con

vers

ion

(-)0.90

0.92

0.94

0.96

0.98

1.00

Temperature (ºC)900 920 940 960

Effic

ienc

y (%

)

90

92

94

96

98

100

► Carbon Capture & Combustion Efficiency

► Char conversion

Carbon Capture Eff.

Combustion Eff.

Results CLOUOC: Cu60AlMgEffect of the Fuel Reactor Temperature

Very high Carbon Capture

efficiencies were found

Char conversion in FR increases with the temperature

Complete combustion

in the fuel reactor is reached

600 kg/MWth

tres

= 6 min

Temperature (ºC)900 920 940 960 980

Rat

e of

cha

r con

vers

ion

(%/s

)0.1

1

10

100

Temperature (ºC)880 900 920 940 960

Effic

ienc

y (%

)

0

20

40

60

80

100

60 times higher

with CLOU

► Char conversion rate► Carbon capture

CLC

CLOU

CLC

CLOU

Comparison CLC & CLOU

Comparison CLC & CLOU

Temperature (ºC)880 900 920 940 960

Effic

ienc

y (%

)

80

85

90

95

100

► Combustion efficiency

CLC

CLOU •

Better combustion in CLOU

•

Low combustion efficiency in CLC is not justified by reactivity of ilmenite

•

The contact between volatiles and oxidant agent is relevant for good combustion

Solids in FR (kg/MWth)10 100 1000 10000

Effic

ienc

y (%

)

0

20

40

60

80

100

Solids in FR (kg/MWth)10 100 1000 10000

Effic

ienc

y (%

)

0

20

40

60

80

100

Combustion

Eff.

Carboncapture Eff.

60 kg/MWth

Combustion

Eff.

Carbon

capture Eff.

Theoretical

predictions TFR

= 950 ºC

Comparison CLC & CLOU

► CLC with ilmenite ► CLOU with Cu60MgAl

CLC: Actions must be taken to increase the

combustion and carbon capture efficiencies

•

Requirement of a carbon separation system to reach high carbon capture

Conclusions CLC & CLOU

► CLC

Key aspects

► CLOU

•

Very high carbon capture efficiency can be reached without a carbon separation system

•

To obtain complete gas combustion an improved design of the fuel reactor or/and an oxygen polishing step should be used

•

An oxygen polishing step is not necesary

because full gas combustion

can be reached with low solids inventory

•

A low cost material (e.g. ilmenite) can be used as oxygen carrier

•

To optimize the cost of the oxygen carrier in the CLOU process considering a long live and/or a low costSeparation from ashes is a key factor

Coal

CO2 + H2ON2 (+O2)

Air Reactor

FuelReactor

Air

H2O(v)and/or

CO2AshAsh

Char

C separationsystem

Coal

CO2 + H2ON2 (+O2)

Air Reactor

FuelReactor

Air

H2O(v)and/or

CO2AshAsh

Char

C separationsystem

•

Requirement of a carbon separation system to reach high carbon capture

Conclusions CLC & CLOU

► CLC

Key aspects

► CLOU

•

Very high carbon capture efficiency can be reached without a carbon separation system

•

To obtain complete gas combustion an improved design of the fuel reactor or/and an oxygen polishing step should be used

•

An oxygen polishing step is not necessary because full gas combustion can be reached with low solids inventory

•

A low cost material (e.g. ilmenite) can be used as oxygen carrier

•

To optimize the cost of the oxygen carrier in the CLOU process considering a long life

and/or a low cost

Separation from ashes is a key factor

CO2

CAPTURE ACTIVITIES IN ICB-CSIC

► Chemical Looping Combustion

► Oxy-fuel Combustion in Fluidized Beds

Oxy-fuel combustion

Fuel flexibility

High combustion efficiency

Good control of temperature

In-situ desulfurization with Ca-based sorbents

Circulating Fluidized Bed Combustor (CFBC) Pulverized Coal Boiler (PC)

AirASU

Heat exchanger

H2 O

CO2

Gas outlet

N2

CoalSorbent

ash O2

FBC

Recirculated Gas

Advantages of CFBC´s

Oxy-fuel projects

Retención de SO2 con sorbentes cálcicos durante la oxicombustiónen lecho fluidizado (OXYRES)Plan Nacional de I+D+I (2008-2011) (CTQ2008-05399/PPQ)

Optimización del proceso de retención de SO2 en la planta de oxicombustión de lecho fluidizado circulante de El Bierzo Fundación CIUDEN (Ref. 20090487)

To study the SO2

retention process of Ca-based sorbents in a oxy-fuel FB combustion plant

To

model

and

optimize, the

SO2

retention

process

in the

30 MWth

oxy-fuel FBC of

CIUDEN

Ca-based sorbentEquilibrium diagram

0

20

40

60

80

100

700 800 900 1000Temperature (ºC)

(kPa

)P C

O2

CaCO3

Non-calcining conditions

CaCO3 CaO + CO2

CaOCaO + SO2 +1/2 O2 CaSO4

CaCOCaCO33 + SO2 +1/2 O2 CaSO4 +CO2

Calcining conditions

Sorbent sulfation pattern depends on operating conditions (T - PCO2 )

Oxy-fuelcombustion

In-situ desulfurization

CaOAir combustion

FBC´s

t (h)0 2 4 6 8 10

Con

vers

ión

de s

ulfa

taci

ón, X

s

0,0

0,1

0,2

0,3

0,4

0,5

0,6900 ºC

950975

850

925

800

García-Labiano et al. Calcium-based sorbents behaviour during sulphation at oxy-fuel fluidised bed combustion. Fuel 90 (2011) 3100

TGA sulfation

60% CO2 ; 3000 ppm SO2

Limestone

sulfation

take

place in two

steps, separated

by pore

plugging

The

sulfation

after

pore

plugging

can be of

great

interest

The

maximum

sulfation

take

place at temperatures

about

900-925 ºC

The

maximum

sulfation

is

obtained

under

calcining

conditions

Long term

TGA tests under

differential

conditions

and

perfectly

controlled

Calcining cond.Non-calcining cond.

Sulfa

tion

conv

ersi

on, X

sTime (h)

AnalyzersCO2 , O2 , CO, SO2

PreheaterP1

P2

Limestone feed system

SO2

Outlet stream

cyclone

CO2O2Air

Furnace

thermocouple

CaCO3 CaO + CO2CaO + SO2 +1/2 O2 CaSO4

CO2

time (min)0 5 10 15 20 25 30

CO

2(%

)

78

79

80

81

82

SO2

(vpp

m)

1800

2000

2200

2400

2600

2800

3000

3200

CO2

SO2

Calcining conditions

CO

2(%

)

time (min)0 5 10 15 20 25 30

38

40

42

44

46

800

1300

1800

2300

2800

3300

CO2

SO2

SO2

(vpp

m)

Non-Calcining conditionsCaCOCaCO33 + SO2 +1/2 O2 CaSO4 +

Sulfation

in batch FB

Short term

tests in FB to

study

the

firstmoments

of

the

sulfation

process

time (min)0 5 10 15 20 25 30

Xs (

%)

0

5

10

15

20

25

30

15-60 %CO2

925 ºC

80-90 %

time (min)0 5 10 15 20 25 30

Xs (

%)

0

5

10

15

20

25

30

CO2 = 15 %

850 ºC

40-90 %

“Granicarb” limestone; 3000 vppm SO2 ; 0.3-0.5 mm

Sulfation

in batch FB

time (min)0 5 10 15 20 25 30

Xs (

%)

0

5

10

15

20

25

30950 ºC

15-90 %CO2

time (min)0 5 10 15 20 25 30

Xs (

%)

0

5

10

15

20

25

30900 ºC

15-40 %CO2

60-90 %

There

is

a zone

near

the

thermodynamic

equilibrium

curve where

calcinationis

so slow

that

sorbent

acts

as non-calcining

conditions.

The

temperature

for

real calcining

conditions

in oxy-fuel shifts

about

20ºC.

Temperature

(ºC)

700 750 800 850 900 950 1000

PC

O2

(kPa

)

0

20

40

60

80

100

CaCO3

CaO

Thermodynamicequilibriumcurve

Effectivecalcination

curve

(Calc. cond)

(Non calc. cond.)

De Diego et al. Characterization of a limestone in a batch fb reactor for sulfur retention under oxy-fuel operating conditions. IJGGC 5 (2011) 1190

Heat exchanger

Continuous Bubbling Fluidized

Oxy-fuel combustion bubbling fluidized bed. 3 kWt

Diameter = 9 cm, Bed height = 40 cm

Perfect control of the solids mean residence time = 2 hoursPerfect control of the solids mean residence time = 2 hours

Oxy-fuel combustion plant

T1

T3

T2

T4

T5

P1

P2

AnalizadorCO2, CO, O2, SO2

Chimney

Cold waterHot water

AirT1

T3

T2

T4

T5

P1

P2

Gas analysisCO2, CO, O2, SO2

O2

CO2

Coal + sorbent

Preheater

Cyclone

Silica sand

SO2

NOxH2 OEvaporator

Simulatedgas flowrecirculation

Oxy-fuel combustion plant

- Temperature

-

Calcining

vs. Non-calcining

conditions

-

Ca/S molar ratio

-

Type

of

fuel

- Type of sorbent

- O2

/CO2

molar ratio

-

Effect

of

recirculated

flue

gas (H2

O, SO2

, NOx, etc.)

Operating

variables

Temperature & Ca/S

Oxy-fuel combustion plant

Lignite

Temperature (ºC)775 800 825 850 875 900 925 950 975

SO2

rete

ntio

n(%

)

0102030405060708090

100

Ca/S = 3

Ca/S = 2

Ca/S = 0

%O2 / CO2 = 35 / 65Calcining conditionsNon-calcining conditions

The

maximum

sulfation

is

obtained

under

calcining

conditions.

The

maximum

sulfation

take

place at temperatures

about

900-925 ºC.

Predictions for CFBC´s

An increase in the mean residence time of the sorbent in CFBCs will produce an increase in the SO2 retention with respect to data herein showed obtained in ICB-CSIC plant.

t (h)15

Granicarb ; 900ºC ; 60%CO2 ; 3000 ppm SO2 ; dp: 0.1-0.2 mm

TGA

0 5 10 20

Sulfa

tion

conv

ersi

on, X

s

0,00,10,20,30,40,50,60,70,80,91,0

TGA data

2

Pilot plant

CFBCs

Oxy-fuel combustion plant

StaffDr. Juan Adánez Research professor CSICDr. Francisco García-Labiano Research scientist CSICDr. Luis F. de Diego Research scientist CSICDra. Pilar Gayán Tenured scientist CSICDr. Alberto Abad Tenured scientist CSIC

Post-DoctoralDra. Teresa Mendiara Juan de la CiervaDr. Javier Abrego JAE-CSICDra. Cristina Dueso FPI fellowshipDra. María Ortíz Post-doctoral researcher

Ph D StudentsAna Cuadrat Research studentAránzazu Rufas Research studentMiguel A. Pans Research studentIñaki Adánez Research studentMarga de las Obras Research studentArturo Cabello Research student

Technical assistantsCristina Igado Engineering technicianNoelia Florez Chemical engineer

HumanHumanresourcesresources

““Combustion and GasificationCombustion and Gasification”” GroupGroupDepartment of Energy and EnvironmentDepartment of Energy and Environment

http://www.icb.csic.es

CO2

CAPTURE ACTIVITIES IN ICB-CSIC:

Chemical-Looping Combustion and Oxy-fuel

A. Abad, F. García-Labiano, L. F. de Diego, P. Gayán,J. Adánez

Ponferrada, 29th-30st

November

2011

abad@icb.csic.es

63rd IEA Fluidized Bed Conversion Meeting

THANK YOU!