碱土金属氧化物基催化剂催化热解生物质研究进展

Research Progress on Catalytic Pyrolysis of Biomass with Alkaline Earth Metal Oxide-based Catalysts

快速热解是生物质高效转化利用的重要方法之一,然而其目标产物生物油因含氧量高、组分复杂等不足而难以直接利用。通过在热解体系中引入碱土金属氧化物基催化剂,可以将热解产物中的氧元素以CO_(2)和H_(2)O等方式脱除,从而实现生物油品质的提升。总结了典型碱土金属氧化物基催化剂对生物质催化热解过程中发生的酮基化、羟醛缩合、开环和侧链断裂反应及机理,讨论了催化剂类型(CaO、MgO、基于碱土金属氧化物的分子筛和活性炭等)、生物质原料、温度、催化剂用量、停留时间、催化方式、催化剂失活等因素对生物油产率与品质的影响,并对生物质催化热解制备高品质生物油及其应用进行了展望。

Fast pyrolysis is one of the most promising methods for the efficient conversion and utilization of biomass.However,the target product,known as bio-oil,is difficult to utilize directly due to its high oxygen content and complex components.Fast pyrolysis of biomass catalyzed by alkaline earth metal oxides is able to remove the oxygen of the pyrolysis products in the form of CO_(2) and H_(2)O,thereby improving the bio-oil quality.This review summarized the reaction mechanism(ketonization,aldol condensation,ring opening and side-chain scission)involved in the catalytic pyrolysis of biomass with the typical alkaline earth metal oxides-based catalysts.Also,the effects of catalysts(CaO,MgO,alkaline earth metal-based zeolites and activated carbons),raw biomass,pyrolysis temperature,catalyst amount,residence time,catalytic fast pyrolysis method and catalyst deactivation on the yield and quality of bio-oil were discussed.Finally,the application of biomass catalytic pyrolysis for producing high-quality bio-oil was prospected,which was expected to provide a theoretical basis for the utilization of biomass resources.