FIRST OPERATING EXPERIENCE ON A 120kW DUAL CIRCULATING FLUIDIZED BED (DCFB) SYSTEM FOR CHEMICAL...

FIRST OPERATING EXPERIENCE ON A 120kW DUAL CIRCULATING FLUIDIZED BED (DCFB)

SYSTEM FOR CHEMICAL LOOPING COMBUSTION

4th International Workshop on In-Situ CO2 Removal

P. Kolbitsch, T. Pröll, J. Bolhàr-Nordenkampf, H. Hofbauer

P. Kolbitsch, T. Pröll, J. Bolhàr-Nordenkampf & H. Hofbauer

First operating experience on a 120kW dual circulating fluidized bed (DCFB) system for chemical looping combustion 2

Outline

Short introduction to chemical looping combustion

The Dual Circulating Fluidized Bed (DCFB) reactor system

Cold flow model results

First experimental results

Conclusions



Chemical looping combustion principles I

A new process for oxidising fuels using metal oxides as oxygen carriers transporting oxygen from combustion air to fuel

no mixing of combustion air and fuel, combustion products (CO2 and H2O) not diluted by N2

Highly exothermal reactions in air reactor

Fuel reactor is exothermic/endothermic depending on fuel and oxygen carrier



Chemical looping combustion principles II

Inherent CO2 separation

No energy penalty for separation of CO2

Gaseous fuels

Solid fuels have to be gasified (potentially inside FR)

Active metals for oxygen carriers: Fe, Co, Ni, Cu, Mn



Chemical looping combustion principles III

Fuel reactor reactions:

→Chemical looping reforming: • partial oxidation• steam reforming

Air reactor reaction:



CLC technology status

Fast fluidized air reactor

Bubbling bed fuel reactor

Potential gas slip in FR (no reactions in freeboard)

However: excellent gas-solid contact needed in both reactors

air

reac

tor

(AR

)

fuelreactor(FR)

LS

LS

air

fuel

exhaustAR

exhaustFR



Proposed systems employing two CFB reactors

stea

mg

asif

ier

air

solid fuel

flue gas

product gas

steam

char

com

bu

sto

r

red

uce

rair

solid fuel

oxidizer exhaust (N2 )

reducer exhaust (CO2 )

steam

oxi

diz

er

Batelle/FERCO gasifier Alstom concept



Dual circulation fluidized bed (DCFB) reactor system I

DCFB features:→Global solids circulation is

controlled by primary reactor fluidization only (eg. air staging)

→Secondary reactor can be optimized towards fuel conversion

→Inherent stabilization of global solids hold up due to the direct hydraulic link between the reactors



Dual circulation fluidized bed (DCFB) reactor system II

DCFB features:→High potential for scale-up

→Optimized gas-solids contact compared to bubbling fluidized beds

→Low reactor volume compared to bubbling fluidized beds (ie. low solids inventory)



AR/FR regime map



DCFB cold flow model (1)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0 20 40 60 80 100Pressure relative to ambient pressure [mbar]

Geom

etrica

l heig

ht [m

]

AR PI cyclone exit

ULS PI 1

ULS PI 26

AR PI 1

FR PI 1

.

V AR = 30.3 Nm3.h-1

.

V FR = 10.1 Nm3.h-1

.

V LLS = 1.5 Nm3.h-1

bed inventory = 5 kg

AR PI 2

AR PI 3

AR PI 4

AR PI 5

AR PI 6

AR PI 7

FR PI 2

3

4

5

FR PI cycl. exit

FR int.LS PI 2, 1

LLS PI




0

20

40

60

80

100

120

0 20 40 60 80 100Part of primary level air in total AR fluidization [%]

Solid

s flux

AR

[kg .

m-2.

s-1]

4.0 kg, LLS 1.5 4.5 kg, LLS 1.5 5.0 kg, LLS 1.5



.

V AR = 30.3 Nm3.h-1

.

V FR = 10.1 Nm3.h-1




0

20

40

60

80

100

120

0 5 10 15 20Gas flow to FR (primary level) [Nm3.h-1]

Solid

s flux

AR

[kg

. m-2.

s-1]




.

V AR = 30.3 Nm3.h-1

0

5

10

15

20

25

30

0 5 10 15 20Gas flow to FR (primary level) [Nm3.h-1]

Solid

s flux

FR [k

g . m

-2.s-1

]




.

V AR = 30.3 Nm3.h-1

Solids Flux Air reactor Solids Flux Fuel reactor



120 kW DCFB pilot rig



Air reactor pressure profileAR pressures CLC ng 165kW l=1.1

0

20

40

60

80

100

120

140

15:45:00

15:50:00

15:55:00

16:00:00

PIR AR1PIR AR2PIR AR3PIR AR4PIR ARfgPIR DC ARPIR HE AR



Results I – natural gas

CO2-yield = 0.87

CH4 conv. = 0.95

Gas compositions CLC natural gas165kW l = 1.1 at 920°C

0

20

40

60

80

100

15:45:00

15:50:00

15:55:00

16:00:00

FR e

xhau

st [v

% (d

ry)]

0

2

4

6

8

10

AR e

xhau

st [v

% (d

ry)]

H2 fuel reactor

CO2 fuel reactor

CO fuel reactor

CH4 fuel reactor

O2 air reactor



Results II – propane

CO2-yield = 0.93

140kW l = 1.2 at 940°C

0

20

40

60

80

100

16:36:00

16:41:00

FR e

xhau

st [v

% (d

ry)]

0

2

4

6

8

10

AR e

xhau

st [v

% (d

ry)]

H2 fuel reactor

CO2 fuel reactor

CO fuel reactorCH4 fuel reactor

O2 air reactor



Conclusions I

DCFB system for scale-up ready chemical looping→Gas-solids contact over the whole fuel reactor height

→Less solids inventory in the fuel reactor due to increased gas-solids contact

→Inherent stabilization of global solids hold up due to a hydraulic link between the two reactors

→Fuel reactor (fluidization regime) may be optimized with respect to fuel conversion

→Staged fluidization of the air reactor controls global solids circulation



Conclusions II

Natural gas operation (CH4 > 97%)

→CH4 conversion = 95%

→CO2 yield = 87%

Propane operation→CO2 yield = 93%



Contact:

www.chemical-looping.at

[email protected]

FIRST OPERATING EXPERIENCE ON A 120kW DUAL CIRCULATING FLUIDIZED BED (DCFB) SYSTEM FOR CHEMICAL...

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