【作者】 王立钢；

【导师】 张泽朋；

【作者基本信息】 中国地质大学（北京） ， 分析化学， 2007， 硕士

【摘要】 本实验是将超临界水降解法与催化降解工艺相结合,在近临界水环境中,利用高效催化剂,在较低温度和压力下,研究聚苯乙烯/聚丙烯共混塑料的降解方法,探索共混塑料裂解油化的新工艺,实现降低成本、优化反应条件、循环利用资源等目标。实验通过对不同催化剂宏观物性(比表面、孔径分布)的分析,筛选出理想的废塑料裂解油化用催化剂——复合催化剂:Y-SiO2-Al2O3(YSA)。它具有良好的比表面及孔径分布,比表面和中孔、微孔的孔容较复合前的SiO2-Al2O3均有显著增加,吸附特性也明显变好。由实验结果得出PS降解的工艺条件为:水与PS的配比为3/1,反应温度340℃,反应时间1h,以Y-SiO2-Al2O3为催化剂,用量3%。在该工艺条件下降解PS,复合催化剂Y-SiO2-Al2O3的降解效果明显优于催化剂SiO2-Al2O3及Y型沸石分子筛:液体收率近93%,高于其他催化剂6～10个百分点。以Y-SiO2-Al2O3为催化剂,通过正交实验研究原料配比(水/混合塑料)、PS/PP、催化剂用量、反应温度和时间等因素对PS、PP共混塑料降解反应的影响。由极差分析及效应曲线可得出优化反应条件为:原料配比(水/混合塑料)为7/2;PS/PP为7/3;催化剂用量4.5%;反应温度360℃;反应时间3h。实验以粘度测试、常减压蒸馏、GC-MS等手段对共混实验的降解产物进行分析。结果表明:在原料配比(水/共混塑料)为7/2;PS/PP为7/3;以Y-SiO2-Al2O3为催化剂,用量4.5%;反应温度360℃;反应时间3h的条件下,PS、PP共混塑料可充分降解(液体收率达到93.34%,气体收率为4.38%,残渣量低于2.3%,产物的平均含碳数小于11)。降解得到的液体产物为轻质油类,主要组成为:甲苯为12.25%、乙苯为46.21%、异丙苯为26.63%及少量短链脂肪族化合物。更多还原

【Abstract】 This paper combines the characteristics of supercritical water method and catalytic degradation process and study the pyrolysis method of the mixed plastics polystyrene(PS) and polypropylene(PP) by efficient use of a catalyst in the near-critical water, at lower temperature and pressure, thus search after a new process of the mixed plastics pyrolysis, which achieve the goals such as reducing cost, optimizing reaction condition, recycling resources and so on.Based on the analysis of macroscopic properties (BET surface area and pore size distribution) of different catalyst, we select the ideal plastic waste fluid cracking catalyst——a composite catalyst: Y-SiO2-Al2O3(YSA), which has good BET surface area and pore size distribution . Its BET surface area, volume of mesopore and micropore increase significantly than those of SiO2-Al2O3, and the adsorption characteristic also significantly changed for the better.We can obtain the degradation process conditions of PS by experimental results: the ratio of water/PS is 3/1, reaction temperature is 340℃, reaction time is 1h,catalyst is Y-SiO2-Al2O3 (amount is 3%). In these process conditions, the degradation effect of PS by Y-SiO2-Al2O3 is superior than by SiO2-Al2O3 or Y-zeolite: the liquid yield is nearly 93%, higher 6～10% than others.As a catalyst to Y-SiO2-Al2O3, we study the effect of raw material ratio (water/mixed plastics), PS/PP, amount of catalyst, reaction temperature and time on the pyrolysis reaction of mixed plastics (PS, PP) by orthogonal experiments. From the range analysis and effect curve, we can draw optimization of the reaction conditions: raw material ratio (water/mixed plastics) is 7/2, PS/PP is 7/3, amount of catalyst is 4.5%, reaction temperature is 360℃and reaction time is 3h.We analyze the pyrolysis products by the means of viscosity test, atmospheric and vacuum distillation and GC-MS. The results show that the mixed plastics PS, PP can be fully degradable (liquid yield is 93.34%, gas yield is 4.38%, residue is less than 2.3% and the average carbon number of products is less than 11), when raw material ratio (water/mixed plastics) is 7/2, PS/PP is 7/3, catalyst is Y-SiO2-Al2O3 (amount is4.5%), reaction temperature is 360℃and reaction time is 3h. The liquid degradation products are light oil, which are mainly composed of 12.25% toluene, 46.21% ethylbenzene, 26.63% cumene and a few short chain aliphatic compounds.更多还原