生物质催化热解制备低碳烯烃的研究进展

Research progresses on production of light olefins from catalytic pyrolysis of biomass

随着我国原油对外依存度增加和国内烯烃供需矛盾加剧,烯烃原料供应紧张,制约了低碳烯烃行业发展。因此,扩大烯烃原料种类、采用非石油原料生产低碳烯烃有着重要意义。生物质作为原料用于制取烯烃有着广阔的研究前景。催化热解制备低碳烯烃工艺简单,克服了传统气化-合成技术制备过程复杂和周期长等缺点。然而,生物质催化热解制备低碳烯烃工艺过程也存在诸多影响因素,如生物质原料特性、催化剂类型和热解工艺条件等。本文着重讨论了原料种类、氢碳有效比、碱金属及碱土金属、温度、催化剂与原料比、反应装置、热解方式和催化剂种类等因素对低碳烯烃产率的影响,其中催化剂是提高低碳烯烃产率的关键因素。目前,ZSM-5分子筛催化剂广泛用于该工艺研究中;由于其易积炭快速失活,催化剂改性成为了研究的热点。针对现研究中改性方式较为单一且改性过程中存在的不足,提出了两种可行的分子筛改性方法。此外,鉴于还未见专门用于催化热解制备低碳烯烃的反应装置,文中给出了一个反应器设计参考性的意见。

With rapid increasing in dependence on foreign crude oil and aggravating in domestic conflict of supply and demand,there is a short of supply in stock of olefins,restricting the development of light olefins industry. Therefore, extending the kind of stock of light olefins and adopting non-petroleum stocks are very important. Using biomass as the stocks to produce light olefins is very promising. The process of catalytic pyrolysis production of light olefins is simple,overcoming the disadvantages,such as complex process and long production period,of traditional gasification process. But it is also affected by many factors,such as biomass properties,catalyst and pyrolysis process conditions. This paper mainly discussed the effects of categories of biomass,H/C effective ratio,AAEMS,temperature,ratio of catalyst to biomass,reactor,the methods of pyrolysis and the type of catalyst,on the yield of light olefins. Among them,the catalyst is the key factor of enhancing the yield of light olefins. At present,ZSM-5 is widely employed in the research of production of light olefins from catalytic pyrolysis of biomass,which is easy to deactivate due to carbon deposit. The modified catalysts have become the popular research subject. Two new methods of modifying catalysts are proposed. A conceptual design of new reactor was suggested,which may be useful for industrial applications.