MCM-41和HZSM-5协同催化对油菜秸秆热解的影响

以油菜秸秆为原料,采用两种方案分层布置催化剂(HZSM-5/MCM-41和MCM-41/HZSM-5),并与MCM-41和HZSM-5单独催化进行对比,从生物油品质和催化剂耐久性两个角度探究协同催化作用机理;对精制生物油有机相进行理化特性分析,采用FT-IR和GC-MS进行成分分析,对催化剂进行耐久性分析。结果表明,与单独催化相比,协同催化所得精制生物油液相产率略有降低,气相产率升高,精制生物油有机相理化特性进一步提高,其中,MCM-41/HZSM-5协同催化所得精制生物油有机相热值较高,为34.31 MJ/kg;精制生物油有机相中含有多种芳香族类物质和少量的羰基类物质,协同催化较单独催化能产生较多的烃类物质及较少的含氧芳香族类物质,其中,MCM-41/HZSM-5协同催化所得精制生物油有机相中烃类物质含量较高,且以单环芳香烃为主;HZSM-5分子筛在300-800℃有两个失重峰,MCM-41分子筛在300-800℃仅有一个失重峰,表明MCM-41催化剂上沉积的焦炭成分单一,较易去除,且协同催化后分子筛表面沉积的焦炭总含量较少。

Synergistic catalysis of MCM-41 and HZSM-5 on rape straw pyrolysis

The rape straw was taken as raw materials, and the HZSM-5 and MCM-41 catalysts were used and loaded into bed in two layers with different ways (HZSM-5/MCM-41 and MCM-41/HZSM-5) to explore the synergistic catalytic mechanism on the basis of bio-oil quality and catalyst durability. The physical and chemical characteristics of organic phase in purified bio-oil were analyzed, the compositions were analyzed by FT-IR and GC-MS, and the durability of catalysts was analyzed by TG. The results show that compared with the singular catalytic reaction, the liquid yield from synergistic catalytic reaction lowers somewhat and the gas yield increases. The physciochemical properties of organic phase in purified bio-oil increase and the organic phase obtained from MCM-41/HZSM-5 synergistic catalytic reaction has a relatively higher calorific value, 34.31 MJ/kg. The organic phase in refined bio-oil contains a variety of aromatic substances and a small amount of carbonyl substances, the synergistic catalytic reaction can produce more hydrocarbons and less oxygen-contained aromatic substances. The MCM-41/HZSM-5 synergistic catalytic reaction can produce higher levels of hydrocarbons in organic phase of refined bio-oil, which are mainly in single ring aromatics. There are two weight loss peaks for deactivated HZSM-5 molecular sieve and only one weight loss peak for deactivated MCM-41 molecular sieve in the range of 300-800℃, which show that the coke deposited on the MCM-41 catalyst has a single composition and is easy to remove and the synergistic catalytic reaction forms less coke.