面向氢能源、燃料电池和二氧化碳减排的制氢途径的选择

This article discusses the processing options for hydrogen production in conjunction with hydrogen utilization, fuel cells, and mitigation of CO2 emissions. It should be emphasized that molecular hydrogen is an energy carrier but not a primary energy resource. Thus H2 must be produced using hydrogen and energy resources. By atomic hydrogen and energy sources, hydrogen can be produced from coal (gasification, carbonization), natural gas and propane gas (steam reforming, partial oxidation, autothermal reforming, plasma reforming), petroleum fractions (dehydrocyclization and aromatization, oxidative steam reforming, pyrolytic decomposition), biomass (gasification, steam reforming, biological conversion), and water (electrolysis, photocatalytic conversion, chemical and catalytic conversion). For fossil fuel-based H2 production in stationary plants such as coal gasification and natural gas reforming, it would be desirable to develop new approaches that produce hydrogen in a more economical and environmentally-friendly process that also includes effective CO2 capture or CO2 utilization as an integral part of the system. A concept called CO-enriched gasification is proposed here for H2 production from gasification of coal and biomass that may be studied further. For mobile fuel processor, there are major challenges in the development of (1) fuel processor for on-site or on-board production of H2 that meets the stringent requirement of CO (<10×10－6 (v/v)) and H2S (<20×10－9 (v/v)) for H2-based proton-exchange membrane fuel cell system, and (2) fuel processor for synthesis gas production for solid-oxide fuel cells that use hydrocarbon fuels. The sulfur contents of most hydrocarbon fuels are too high for use in fuel cell reformer and in anode chamber, if when such fuels meet EPA sulfur requirements in 2006～2010 for automotive vehicles. Removal of organic sulfur before reforming and cleaning inorganic sulfur after reforming would be important for H2 and syngas production for fuel cells, but conventional desulfurization methods are not suitable for fuel cell applications. Hydrogen energy and fuel cell development are closely related to the control of CO2 emissions.