The direct electrochemical oxidation of coal gas was studied by pyrolyzing a sample of Ohio #5 coal in flowing Ar at 700, 800, 900, and 950 °C and transporting the resulting gaseous products to a Cu (Copper) anode solid oxide fuel cell (SOFC) operated at 950 °C. Pyrolysis of coal at 700 °C produced a H2-rich coal gas containing 89% H2, 4% CO, 6% CH4, 1% CO2, and sulfur compounds (i.e., 1% COS and 1% SO2), which yielded a maximum current density of 320 mA/cm2 at 0.5 V. Raising the pyrolysis temperature from 700 to 950 °C increased the CO concentration in the coal gas (i.e., 42 vol % CO), which in turn reduced the fuel cell maximum current density. No sulfur compounds were present in the coal gas produced at temperatures higher than 700 °C. Coal gas fuel operation did not degrade the fuel cell performance. A fuel composition of 25 vol % CH4 in He generated a current density of 340 mA/cm2 at 0.5 V. These results demonstrated that the Cu anode is effective for the electrochemical oxidation of sulfur-containing coal gas at 950 °C. The addition of CO2 and D2O to the pyrolysis reactor led to the formation of CO and HD, indicating the occurrence of reforming reactions. Diffuse reflectance infrared Fourier transformation (DRIFT) spectra showed that coal pyrolysis proceeded by dehydrogenation of hydroaromatics, dealkylation of aromatics, and oxidation reactions, leading to the formation of coke with a surface containing C−O, C−S, and S−O bonds. The results of the fuel cell performance strongly support the feasibility of direct power generation from coal gas in a Cu-anode SOFC.
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