面向氢能源、燃料电池和二氧化碳减排的制氢途径的选择

对氢气的多种制造途径加以探讨，也涉及到氢能的利用、燃料电池以及二氧化碳的减排。需要指出的是氢气并非能源，而只是能量的载体。 所以氢能的发展首先需要制造氢气。对于以化石燃料为基础的制氢过程，如煤的气化和天然气重整，需要开发更经济和环境友好的新过程，在这些新过程中要同时考虑二氧化碳的有效收集和利用问题。对于煤和生物质，在此提出了一种值得进一步深入研究的富一氧化碳气化制氢的概念。对于以氢为原料的质子交换膜燃料电池系统，必须严格控制制备的氢气中的一氧化碳和硫化氢；对于以烃类为原料的固体氧化物燃料电池，制备的合成气中的硫也需严格控制。然而，传统的脱硫方法并不适宜于这种用于燃料电池的极高深度的氢气和合成气的脱硫。氢能和燃料电池的发展是与控制二氧化碳排放紧密相关的。

Overview of hydrogen production options for developing hydrogen energy, fuel processing for fuel cells and mitigation of CO2 emissions

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.