coal electrochemical conversion in solid oxide direct carbon...
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Coal Electrochemical Conversion in Solid Oxide Direct Carbon Fuel Cell (SO-DCFC)
Prof. Dr. Ningsheng Cai Deputy director of Department of Thermal Engineering at Tsinghua University; Deputy director of both National Engineering Research Center of Clean Coal Combustion Expert group leader for heavy-duty gas turbine grand project; Expert group member of grand project for demonstration of coal poly-generation system
Assistant Prof. Dr. Yixiang Shi Assistant professor in Department of Thermal Engineering at Tsinghua University. Current research activities include direct carbon fuel cell, solid oxide fuel cell, SOFC/GT hybrid system and IGCC poly-generation systems evaluation.
Collaboration: Prof. Ahmed F. Ghoniem from MIT Prof. B.A. Glowacki and Prof. V. Kumar from Cambridge University
Coal-basedSOFC
HC-basedSOFC
SOFCThermal Reformer
MCFCThermal Reformer
PAFC(CO<5%)
PEMFC(CO<5ppm)
80oC
200oC
600oC
500oC~1000oC
500oC~1000oC
500oC~1000oC
H2/CO Shift Reaction
Conversion toH2/CO
Gasification
Gas cleaning
CO Selective Oxidization
S-Removal
Solid FuelCoal, Coke
Liquid Fuel
Natural Gas
Hydrogen
Under development
Increasing complexity of fuel processing and decreasing efficiency
N. F. Brandon, S. Skinner, B. C. H. Steele, Annu. Rev. Mater. Res. 2003.33:183~213
v Abundant fuel source; easy for storage and transport;
v High theoretical efficiency and energy density;
v High reaction activities with high operating temperature;
v No needs for noble metal catalysts;
Coal based SO-DCFCs
Electronic conductorElectronic conductor
Ionic conductorIonic conductor
Porous cathode
Porous cathode
ElectrolyteElectrolyte
0La
x
Porous anode
Porous anode
LeLc
O2- e-
CO
O2 CO2
TPB
O2-e-
O2 e-
CO2
O2-
CarbonCarbon
Carbon particleCarbon particle
TPB
Needs for performance and operation stability improvement
Solid Oxide electrolyte DCFCs �
Research Content
Research focus: l Reaction mechanism: Clarify the carbon electrochemical oxidation mechanisms in SO-DCFC l Performance improvement: Effects of fuel type, operating conditions, contaminant compositons on the cell performance �l Reactor design: Novel Coal-based SO-DCFC proto type design, fabrication and optimization
Goal: High efficiency, clean, cost-effective way for coal direct electrochemical conversion to electricity
Proposed researches
Research framework
C
TPB
O2-2e-
CO CO2
Gasification
Electrochemicaloxidization
Mass transfer
C
CO
YSZNiTPB
Fuel inducing
tube
Ceramic plate
Alumina tube
Thermo-couple Anode current collector
Cathode current collector
Pt mesh
Button cell
Oxidant chamber
Oxidant inducing tube
Fuel
Oxidant
Sealing interface
l Coupling effects of carbon electrochemical oxidation and gasification
l Performance analysis and improvement, especially considering introducing ionic conductor catalyst
l Proto type design and optimization (Enhancement of heat and mass transport by using fluidized-bed carbon electrode )
Mutli-physical modeling at different time-space scales
Validation Feedback
(Collaboration with Prof. Ahmed F. Ghoniem- MIT, Prof. B.A. Glowacki and Prof.V. Kumar - Cambridge) �
0 10 20 30 40 50 600.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Vol
tage
(V)
Current Density (mA/cm2)
850oC 830oC 805oC 775oC 735oC
R&D of DCFC in Department of Thermal Engineering, Tsinghua University
Globe valve
Reducing valve Check valve
0～500sccmO2
Cathode vent
Mass flowmeter
FI
Gas chromatography
Condenser
0～500sccm
FI
CO2
FI
0～500sccm
H2
FI
0～500sccm
Ar
FI
0～50sccm
Cathode gas
Anode gas
ZAHNER IM6exElectrochemicalWorkstation Counter
Reference
Test Sence
Anode vent
Drying tube
Triple valve
Circulating cooling water
N2
Globe valve
Reducing valve Check valve
Mass flowmeter
Globe valve
Reducing valve Check valve
Mass flowmeter
Globe valve
Reducing valve Check valve
Mass flowmeter
Globe valve
Reducing valve Check valve
Mass flowmeter
Experimental setup Elementary reaction DCFC modeling
Performance improvement (adding K, Ni, Ca salt)
C
C
C
H2
O2
H2O
CO2
CO
5
4
6
3
2
1
7
8
9
10
11
12
_
+
Bubbling fluidized bed electrode design