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CO2 CAPTURE EXPERIMENTS FROM
CANMETENERGY PILOT-SCALE DUAL
FLUIDIZED BED SYSTEM
Dennis Lu*, Robert Symonds, Scott Champagne
CanmetENERGY
5th IEA-GHG Network Meeting, Cambridge, UK
CanmetENERGY CaL Research Program
2000’s
2010+
2006-2009
CYCLONE
STACK
FUEL HOPPER
BAGHOUSE
LIMESTONE
HOPPER
SOLIDS
DISCHARGE
CONDENSER
RETURN LEG
RECYCLE
BLOWER
WATER COOLER
FEED SCREW
SECONDARY FLOW
SECONDARY
OXYGEN
AIR
PRIMARY
OXYGEN
DRAIN
WINDBOX
PRIMARY FLOW
Concept Demo
Oxy - CFBC
Pilot Demo
 TGA
 75 kW CFBC
 Continuous operations
 Fixed bed
 Batch operations
 Sulphur capture
Steam addition
 Attrition
 Sorbent modification
Steam addition
 Real flue gases
CanmetENERGY Dual-Fluidized CaL System
Specifications
 Calciner:
T < 1050 °C
P – atmospheric
ID = 0.1 m
H = 5.0 m
Vf < 6.0 m/s
Fuel type: solid fuels
Fuel feed rate < 10 kg/h
Oxygen stream = 99.9%
 Carbonator:
T < 1050 °C
P – atmospheric
ID = 0.1 m
H = 3.0 m
Vf < 2.0 m/s
Solid transfer rate < 50 kg/h
Objectives
 Continuous operation:

CO2 capture performance

Sorbent evaluation
 Realistic operating conditions:

Oxy-fuel combustion as calcination

Fuel-S involved in sorbent regeneration

S, Cl streams in carbonation flue gas

Steam in carbonation

Real flue gases carbonation from burning gas and solid fuels
Operating Conditions
Temperature:
 Calcination @ 850-910C
 Carbonation @ 600-700C
Gas stream:
 Calcination with oxy-fuel combustion of low-ash wood pellets, CO2 in the
recycled flue gas up to >90%
 Carbonation with synthesis gases of 15% CO2 and 85% air
Sorbent:
 Limestone: Cadomin, pre-treated limestone
 Cadomin: CaO=51.76%, MgO=2.18%, SiO2=2.13%
 Size: 0.18-0.8 mm
Solid transfer rate:
 Max: 100 kg/h
 Operation: 20-50 kg/h
 Options: via cyclone loop seal, and/or overflow
Oxy-fuel Combustion in Calcination
Calciner Conditions
Bed Material Inventory
CO2 Capture in Carbonator
Comparison with Steam Addition
SEM and EDX
Carbonated with Steam Present
Carbonated without Steam Present
Limestone
BET
Comparison with Reactor Model
 Compared obtained results with model developed by Alonso et al.
(2009)1
 Assumptions:
 Perfect mixing of solids
Heat
Coal
 Plug flow for gas phase
New or Existing
Combustor
N2
N2
Bubbling Fluidized
Bed
Air
CO2
CaCO3
 Complete calcination
 Steady state
Carbonation
Petroleum coke
O2
 Model Inputs:
H2O
CaO
Calcination
Circulating
Fluidized Bed
90%+ CO2,
Balance N2, O2,
H2O
Heat
 Carbonator T = 650°C
 Average sorbent conversion from sample analysis
 ~15% CO2 at inlet
 CaO flow from calciner (~33 kg/h)
1. Alonso, M.; Rodriguez, N.; Grasa, G.; Abanades, J.C. Modeling of a fluidized bed carbonator reactor to capture CO2 from a combustion flue gas. Chem. Eng. Sci. 2009, 64, 883-891.
Model Fit Results
Conversion = 15%
Ecarb (Experimental) = 92.1%
Ecarb (Predicted) = 93.6%
Topics in Near Future
 Work on real combustion flue gas from burning
natural gas, then flue gas from coal
 Coal and petcoke as oxy-fuel in sorbent
calcination to investigate the effects of
sulphation and ash on CO2 capture
performance
 Type of sorbents and sorbent modifications
 Modelling development
 Operation optimization
 Demonstrate the integration of CaL and CLC
in CO2 capture, as well in gasification and
hydrogen production
Conclusions
 CaL technology was demonstrated at CanmetENERGY pilot facility,
over 35 runs and 400 hours of testing campaign were completed
 Dual-fluidized beds pilot-scale system using limestone is a practical,
flexible operation process for post-combustion CO2 capture
 Over 90% CO2 capture efficiency can be achieved over a wide range
of sorbent types and operating conditions
 Steam in carbonation showed a robust stream to enhance sorbent
CO2 intake performance, which is involved in realistic wet flue gas
 Sorbent regeneration in oxy-fuel calcination can be fully completed
 Biomass showed an ideal fuel for sorbent regeneration in oxy-fuel
combustion, in terms of low-S, low-ash and high-moisture in flue gas
 Sorbent particle attrition and elutriation are the main issues of the
process and can be solved with sorbent make-up
Acknowledgements
Funding for this work was provided by Natural
Resources Canada through the Program of
Energy Research and Development
Questions ?
Contacts:
[email protected]
[email protected]
[email protected]
CanmetENERGY Dual-Fluidized CaL System
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A
Solids Loading
Vent
(>90% CO2)
Flare
B
RECYCLE GAS COOLER
/ CONDENSER
B
FLUE GAS COOLER
/ CONDENSER
Vent
C
CFBC
CYCLONE
RECYCLE GAS
CONDENSATE KO
SOLIDS
TRANSFER
LINE
CYCLONE
Water
FLUE GAS
CONDENSATE KO
C
BFB
CYCLONE
Water
D
E
D
CFBC FUEL HOPPER
E
F
G
(1) Carbonator FB Mode:
(a) Bubbling
(b) Circulating
(c) Moving
(2) Control Transfer Rate:
(a) To Carbonator
(b) To Calciner
(3) Pellet Attrition:
(a) Too soft – No screw feeder
(b) Too hard – Transfer line wear
(4) Loop Seal Reliability
Air
H
Solids Loading
I
CFBC SORBENT HOPPER
(LIMESTONE / DOLOMITE / PELLETS)
J
CFBC CROSS
CONVEYER
K
F
Questions:
Air
G
H
I
J
K
Bottled Gases
Air
L
M
L
Steam
BFB to CFBC TRANSFER
CONVEYER
M
B
Air
N
Solutions (based on selected design):
A
CONE VALVE
(1) Bubbling
Solids Loading
O
LOOP SEAL
(2) Transfer
Solids Sample Ports
(A) Carbonates – Carbonator
(B) Carbonates – Transfer Line
(C) Calcines – Loop Seal
(D) Calcines – Transfer Line
(E) Calcines – Calciner
P
Q
C
–
(3) Flexibility
R
S
Bottled Gases
(4) Sampling
Air/O2
RECYCLE BLOWER
T
Steam
–
–
–
–
–
–
–
N
Minimizes required design / fabrication time
Minimizes required bottled gases
Minimizes attrition in reactor
Screw conveyor from carbonator to calciner
using overflow
Loop seal from calciner to carbonator using a
cone valve or overflow using eductor
Can control inventory in both reactors
Can control transfer rate
Either CFB or BFB operation
Can control carbonation time
Easy to convey solids from carbonator to
calciner
Can control recycle material (calciner)
Can remove solids sample from many
location
O
P
Q
R
S
T
D
Air
U
–
–
–
–
EDUCTOR
E
U
REV.
1
DESCRIPTION
PRELIMINARY DESIGN
DATE
OCT 2011
BY
RTS
DRAWN BY:
R. Symonds
APPROVED BY:
ISSUED:
JUNE 2011
SCALE:
NONE
Bldg 1 Mini-bed Facility NRCAN-CEPG
Reactor Configurations
DRAWING NO
SHEET NO
REVISION NO
434400-D-1000-R2
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