生物质炭对聚丙烯热解焦油降解作用分析

Degradation analysis of polypropylene pyrolysis tar by carbon-based catalyst

以玉米秸秆为原料,分别负载Fe_2O_3,Na_2CO_3,CaO得到生物质炭基催化剂,利用炭基催化剂对聚丙烯(PP)进行催化热解反应,采用FTIR和GC-MS方法对热解产物中的焦油进行分析,研究了液体产物产率和焦油成分的变化规律。实验结果表明,炭基催化剂可明显降低PP的液相产物产率,催化剂催化作用效果由大到小顺序为:炭-Na_2CO_3>炭-CaO>炭-Fe_2O_3>生物质炭。炭基催化剂均能促进焦油中醚类、酮类、取代苯、醇酚和芳香醚等裂解、重整,生成热解气和焦炭;可以促进取代苯脱甲基和芳香构化,促进醛类加成氧化成醇类和酸类。PP热解液相产物主要成分有苯、茚、萘、菲、烷烃、烯烃、环烯烃、芳香烃及其衍生物。采用炭-Na_2CO_3进行热解时,液体产物中十四烷相对含量很大,芳香类和含氧有机物种类增加,但含量降低,萘、苯酚及其衍生物的含量增加,菲的含量减小。

Corn stalk as raw material was loaded with Fe2O3,Na2CO3 and CaO,respectively,to obtain biomass carbon-based catalysts.The tar of polypropylene(PP),which was pyrolyzed by carbonbased catalysts,was analyzed by FTIR and GC-MS.The change rules of the tar yield and the tar composition under different reaction conditions were explored.The results showed that the liquid phase product yield of PP could be significantly reduced by the carbon-based catalysts and the order of the catalytic effects of the catalysts was:carbon-Na2CO3>carbon-CaO>carbon-Fe2O3>biomass carbon.The carbon-based catalysts could promote the cracking and reforming of ether,ketone,substituted benzene,alcohol phenol and aromatic ether in tar to generate pyrolysis gas and coke.They could promote the demethylation and aromatization of substituted benzene and the oxidation of aldehydes into alcohols and acids.The main components of PP pyrolysis liquid phase products were benzene,indene,naphthalene,phenanthrene,alkane,olefin,cyclic olefin,aromatic hydrocarbon and their derivatives.When carbon-Na2CO3 was used for pyrolysis,the relative content of tetradecane in liquid products was very high.The number of aromatic and oxygen-containing organic compounds increased.However,the content of naphthalene,phenol and their derivatives increased,while the content of phenanthrene decreased.