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

Transcription

1 4th International Workshop on In-Situ CO 2 Removal FIRST OPERATING EXPERIENCE ON A 120kW DUAL CIRCULATING FLUIDIZED BED (DCFB) SYSTEM FOR CHEMICAL LOOPING COMBUSTION J. Bolhàr-Nordenkampf, H. Hofbauer

2 Outline Short introduction to chemical looping combustion The Dual Circulating Fluidized Bed (DCFB) reactor system Cold flow model results First experimental results Conclusions fluidized bed (DCFB) system for chemical looping combustion 2

3 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 (CO 2 and H 2 O) not diluted by N 2 Highly exothermal reactions in air reactor Fuel reactor is exothermic/endothermic depending on fuel and oxygen carrier fluidized bed (DCFB) system for chemical looping combustion 3

4 Chemical looping combustion principles II Inherent CO 2 separation No energy penalty for separation of CO 2 Gaseous fuels Solid fuels have to be gasified (potentially inside FR) Active metals for oxygen carriers: Fe, Co, Ni, Cu, Mn fluidized bed (DCFB) system for chemical looping combustion 4

5 Chemical looping combustion principles III Fuel reactor reactions: Chemical looping reforming: partial oxidation steam reforming Air reactor reaction: fluidized bed (DCFB) system for chemical looping combustion 5

6 CLC technology status Fast fluidized air reactor exhaust AR Bubbling bed fuel reactor Potential gas slip in FR (no reactions in freeboard) However: excellent gas-solid contact needed in both reactors air reactor (AR) LS LS exhaust FR fuel reactor (FR) fuel air fluidized bed (DCFB) system for chemical looping combustion 6

7 Proposed systems employing two CFB reactors product gas flue gas reducer exhaust (CO 2 ) oxidizer exhaust (N 2 ) solid fuel steam gasifier char combustor solid fuel reducer oxidizer steam air Batelle/FERCO gasifier steam Alstom concept fluidized bed (DCFB) system for chemical looping combustion 7 air

8 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 fluidized bed (DCFB) system for chemical looping combustion 8

9 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) fluidized bed (DCFB) system for chemical looping combustion 9

10 AR/FR regime map fluidized bed (DCFB) system for chemical looping combustion 10

11 DCFB cold flow model (1) Geometrical height [m] AR PI cyclone exit FR PI cycl. exit AR PI 7 ULS PI 1 FR int.ls PI 2, 1 FR PI 2 AR PI 6 ULS PI 2 AR PI 5 AR PI 4 AR PI 3 AR PI 2 FR PI 1 AR PI 1. V AR = 30.3 Nm 3. h -1. V FR = 10.1 Nm 3. h -1. V LLS = 1.5 Nm 3. h -1 bed inventory = 5 kg LLS PI Pressure relative to ambient pressure [mbar] fluidized bed (DCFB) system for chemical looping combustion 11

12 DCFB cold flow model (2) Solids flux AR [kg. m -2. s -1 ] kg, LLS kg, LLS kg, LLS kg, LLS kg, LLS kg, LLS kg, LLS kg, LLS kg, LLS 0.5. V AR = 30.3 Nm 3. h -1. V FR = 10.1 Nm 3. h Part of primary level air in total AR fluidization [%] fluidized bed (DCFB) system for chemical looping combustion 12

13 DCFB cold flow model (3) Solids Flux Air reactor Solids Flux Fuel reactor V AR = 30.3 Nm 3. h kg, LLS kg, LLS kg, LLS kg, LLS kg, LLS kg, LLS kg, LLS kg, LLS kg, LLS 0.5 Solids flux AR [kg. m -2. s -1 ] kg, LLS kg, LLS kg, LLS kg, LLS kg, LLS kg, LLS 1.0 Solids flux FR [kg. m -2. s -1 ] V AR = 30.3 Nm 3. h kg, LLS kg, LLS kg, LLS Gas flow to FR (primary level) [Nm 3. h -1 ] Gas flow to FR (primary level) [Nm 3. h -1 ] fluidized bed (DCFB) system for chemical looping combustion 13

14 120 kw DCFB pilot rig fluidized bed (DCFB) system for chemical looping combustion 14

15 Air reactor pressure profile 140 AR pressures CLC ng 165kW l= PIR AR1 PIR AR2 PIR AR3 PIR AR4 PIR ARfg PIR DC AR PIR HE AR :45:00 15:50:00 15:55:00 16:00:00 fluidized bed (DCFB) system for chemical looping combustion 15

16 FR exhaust [v% (dry)] CO 2 fuel reactor H 2 fuel reactor CO fuel reactor CH 4 fuel reactor Results I natural gas Gas compositions CLC natural gas 165kW λ = 1.1 at 920 C O 2 air reactor CO 2 -yield = 0.87 CH 4 conv. = AR exhaust [v% (dry)] :45:00 15:50:00 15:55:00 16:00:00 fluidized bed (DCFB) system for chemical looping combustion 16

17 100 Results II propane 140kW λ = 1.2 at 940 C 10 FR exhaust [v% (dry)] H 2 fuel reactor CO fuel reactor CH 4 fuel reactor CO 2 fuel reactor O 2 air reactor CO 2 -yield = AR exhaust [v% (dry)] 0 16:36:00 16:41:00 0 fluidized bed (DCFB) system for chemical looping combustion 17

18 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 fluidized bed (DCFB) system for chemical looping combustion 18

19 Conclusions II Natural gas operation (CH 4 > 97%) CH 4 conversion = 95% CO 2 yield = 87% Propane operation CO 2 yield = 93% fluidized bed (DCFB) system for chemical looping combustion 19

20 Contact: fluidized bed (DCFB) system for chemical looping combustion 20