Development of Ni- and Co-based Alloy Catalysts for Steam Reforming of Biomass Tar
Development of Ni- and Co-based Alloy Catalysts for Steam Reforming of Biomass Tar
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DOI：
10.1627/jpi.56.253
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发表时间：
2013
影响因子：
1
通讯作者：
Dalin Li;Lei Wang;M. Koike;K. Tomishige
中科院分区：
文献类型：
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作者：
Dalin Li;Lei Wang;M. Koike;K. Tomishige
由于生物质资源的可再生性和可持续性，利用生物质发电和生产液体燃料和化学品引起了人们的广泛关注。生物质转化为合成气和氢气1）~4）是费托合成法生产液体燃料和甲醇合成法生产化学品的常用发电技术之一。将生物质转化为合成气和氢气的常规方法是用空气的非催化气化，其通常在非常高的温度（>1073 K）下进行。特别是，减少副产品焦油含量需要在非常高的温度下操作4）。在非催化气化系统中，由于通常使用空气作为气化剂，所以产品气用氮气稀释。稀释的产物气体不适合于将合成气催化转化为烃和甲醇，因为这些反应需要高压。为了避免产品气体的稀释，使用蒸汽作为气化剂。蒸汽作为气化剂的反应性不如空气高。因此，用蒸汽气化生物质需要较高的反应温度，这会降低能量效率，而在合成气和氢气的生产中更高的能量效率需要降低反应温度。为了解决这一问题，人们开发了低温下生物质热解焦油的催化水蒸气重整。生物质在低温（如773 K）下热解产生高产率的挥发性有机化合物混合物，称为焦油或生物油2）。如果能够在较低温度下通过水蒸气重整实现焦油的催化转化，则生物质低温气化制合成气和氢气将是可行的。该方法需要开发用于生物质焦油的蒸汽重整的催化剂，特别是改进催化剂的活性和稳定性。Rh等贵金属是生物质转化为合成气的有效组分5）~15）。然而，贵金属的高成本和有限的可用性要求进一步开发非基于贵金属的催化剂。Ni和Co金属对烃类和含氧化合物的水蒸气重整反应具有催化作用，用合适的氧化物或其它金属对Ni和Co金属进行改性可以提高催化性能16）~25）。我们的小组已经报道了添加氧化铈26）~30）和253 Journal of the Japan Petroleum Institute，56，（5），253-266（2013）。
Utilization of biomass for power generation and production of liquid fuels and chemicals has attracted much attention because of the renewability and sustainability of biomass resources. One of the common technologies for power generation, the production of liquid fuels by Fischer-Tropsch synthesis and chemicals by methanol synthesis, is the conversion of biomass to synthesis gas and hydrogen1)~4). A conventional method for biomass conversion to synthesis gas and hydrogen is non-catalytic gasification with air, which has usually been carried out at very high temperature (>1073 K). In particular, reduction of the tar content as a by-product requires operation at very high temperature4). In the non-catalytic gasification system, the product gas is diluted with nitrogen because air is usually used as the gasifying agent. The diluted product gas is not suitable for the catalytic conversion of synthesis gas to hydrocarbons and methanol because these reactions require high pressure. In order to avoid dilution of the product gas, steam is used as the gasifying agent. The reactivity of steam as a gasifying agent is not as high as that of air. Therefore, the gasification of biomass with steam needs higher reaction temperature, which can decrease the energy efficiency, whereas higher energy efficiency in the production of synthesis gas and hydrogen requires that the reaction temperature should be lowered. To solve this problem, catalytic steam reforming of tar derived from the pyrolysis of biomass at lower temperature has been developed. Biomass pyrolysis at low temperature such as 773 K gives high yield of a mixture of volatile organic compounds called tar or biooil2). If the catalytic conversion of this tar can be achieved by steam reforming at lower temperature, gasification of biomass to synthesis gas and hydrogen at low temperature will be feasible. This process requires the development of catalysts for the steam reforming of biomass tar, in particular, improved activity and stability of the catalyst. Noble metals such as Rh are effective components for the conversion of biomass to synthesis gas5)~15). However, the high cost and limited availability of noble metals demands the further development of catalysts not based on noble metals. Ni and Co metals are known to catalyze the steam reforming reactions of hydrocarbons and oxygenates, and the modification of Ni and Co metals with suitable oxides or other metals can improve the catalytic performance16)~25). Our group has reported that the addition of cerium oxide26)~30) and 253 Journal of the Japan Petroleum Institute, 56, (5), 253-266 (2013)