生物质与供氢甲醇共催化热解耦合集成优化制备芳烃的研究

Production of aromatic hydrocarbon by catalytic co-pyrolysis coupling optimization of biomass and hydrogen supply reagent

为了提高目标产物的产率以及选择性,以HZSM-5介孔分子筛为催化剂,采用高有效氢碳比化合物--甲醇与生物质进行催化共热解,探讨热解温度、催化温度、有效氢碳比以及醇的种类对芳烃的产率、选择性以及催化剂的抗积碳性能的影响。结果表明,芳烃的产率以及选择性随着生物质与供氢试剂共催化热解时有效氢碳比的增加而显著增加,尤其是二甲苯的选择性,二者之间存在协同效应,当热解温度为400℃,催化温度550℃,甲醇的进样量为2 mL/min,氮气流速为200 mL/min时,其苯及其同系物等芳烃含量达到81.34%,单环芳烃(SBTXE)含量达到71.75%,而二甲苯的选择性达到40.81%,同时,供氢甲醇的添加提高了催化剂的抗结焦能力,使其石墨化焦炭含量增加。

In order to enhance aromatic hydrocarbon yield and selectivity,catalytic co-pyrolysis of biomass and methanol with higher effective hydrogen to carbon ratio(H/Ceff) was conducted with HZSM-5 catalyst in a fixed-bed reactor.Effect of pyrolysis temperature,catalytic temperature,weight hourly space velocity(WHSV) and alcohols(methanol,ethanol,ethylene glycol and glycerol) on the yield,selectivity of aromatic hydrocarbons and the coke deposition resistance of the catalyst were investigated.The results showed that bio-derived aromatic hydrocarbon can be formed through Diels-Alder cycloaddition reaction and catalyst-induced hydrocarbon pool.It was found that the yield and selectivity of aromatic hydrocarbons increase significantly with the increase of the effective hydrogen-carbon ratio,during the co-catalytic pyrolysis of biomass and hydrogen donor,moreover,obviously increase the selectivity of xylene.Additionally,an apparent synergistic effect between biomass and methanol was observed during catalytic co-pyrolysis.With the consideration of aromatic hydrocarbon yield and selectivity in bio-oil,the maximum yield of aromatic hydrocarbons was 81.34%,mono aromatic yield(SBTXE) was 71.75%,and the selectivity of xylene was 40.81% were obtained under the optimum conditions of pyrolysis temperature was 400 ℃,the catalytic temperature was 550 ℃,methanol was 2 mL/min,nitrogen flow rate was 200 mL/min.At the same time,the addition of hydrogen supply reagent(methanol) improved the anti-coking deposition ability of the catalyst and increases the content of graphitized coke.