【作者】 雷火星；

【导师】 刘福胜；

【作者基本信息】 青岛科技大学 ， 化学工艺， 2005， 硕士

【摘要】 本文采用水热合成法合成出一系列金属（Al、Zr、Mo）掺杂和强酸性基团(如BO₃^3-、SO₄^2-等)及ZrO₂改性的MCM-41中孔分子筛催化剂,并将其首次应用于聚烯烃的催化裂解反应。采用XRD、FT-IR、BET、ESR、NH₃-TPD对其结构及酸强度进行了表征。结果表明:所合成的催化剂具有中孔分子筛的特征结构,良好的长程有序性和结晶度;强酸基团已存在于中孔分子筛上,从而产生强酸中心。以高密度聚乙烯（HDPE）、低密度聚乙烯（LDPE）和聚丙烯（PP）的裂解反应为模型反应,对各种强酸性中分子筛的催化裂解性能进行评价,结合催化剂结构表征的结果,研究各种强酸性中孔分子筛的结构及酸强度与催化性能之间的关系。实验结果表明:对于HDPE和LDPE的催化裂解反应,催化剂的酸性强弱是影响催化活性的主要因素;而对PP,催化剂的孔结构是影响催化活性的主要因素。 以催化效果较好的强酸性中孔分子筛作为催化剂,详细考察了Si/M（M=Al、Zr、Mo）比、催化剂用量、反应温度以及反应时间等因素对模型反应结果的影响,获得了较佳的反应条件。确定Al-MCM-41（Si/Al=40）催化裂解LDPE较佳的反应条件为:反应温度420℃、Al-MCM-41/LDPE（质量比）=0.02、反应时间70min,在上述条件下,LDPE的转化率分为97.1%,其中液体产物的收率83.6%。确定Al-MCM-41（Si/Al=40）催化裂解HDPE较佳的反应条件为:反应温度430℃、Al-MCM-41/HDPE（质量比）=0.05、反应时间40min,在上述条件下,HDPE的转化率分为87.4%,其中液体产物的收率为74.9%。确定Al-MCM-41（Si/Al=40）催化裂解PP较佳的反应条件为:反应温度370℃、Al-MCM-41/PP（质量比）=0.01、反应时间30min,在上述条件下,PP的转化率分为94.9%,其中液体产物的收率84.3%。确定ZrO₂/Mo-MCM-41（Si/Mo=80）催化裂解PP较佳的反应条件为:反应温度400℃、ZrO₂/Mo-MCM-41（质量比）=0.02、反应时间50min,在上述条件下,PP的转化率分为96.6%,其中液体产物的收率88.9%。 本研究属资源再利用环保项目,具有较高的环境效益、社会效益和广阔的应用前景。通过该课题的研究工作,为强酸性中孔分子筛在催化裂解聚烯烃反应中的应用提供了理论依据。更多还原

【Abstract】 In this study, several mesoporous molecular sieves, containing Al、 Zr、 Mo, were synthesized by hydrothermal system and some strong acidic groups like BO₃^3-, SO₄^2-and ZrO₂,were incorporated into the frame of the mesoporous molecular sieves to obtain the strong acidic mesoporous molecular sieves catalysts. The obtained materials were firstly used as catalysts in pyrolysis of polyolefins. The synthesized Mesoporous molecular sieves were characterized by XRD, FT-IR, BET, ESR and NH₃-TPD. The results show that the obtained materials are of the characteristics of mesoporous molecular sieves, better long-range order and crystallinity, and that super acidic groups have been combined with the frame of mesoporous molecular sieve so that the acidity of MCM-41 was improved. The catalytic cracking performance of different strong acidic mesoporous molecular sieves catalysts was compared by model reactions of catalytic pyrolysis of HDPE, LDPE and PP. According to the characterization of these catalysts, the relationship between pore structure, acidities and catalytic activities of different strong acidic mesoporous molecular sieves was studied. The results indicate that the strength of acid has more significant effect on catalytic pyrolysis of HDPE and LDPE. However the catalytic activity of mesoporous molecular sieves can be controlled by the pore structures of catalysts in catalytic pyrolysis of PP.The catalysts that were of best catalytic activities were used in catalytic pyrolysis of polyolefins. Influences of reaction conditions such as Si/M（M=Al、 Zr、 Mo） ratio, reaction time, temperature and dosage of catalyst on the pyrolysis were examined and the optimum conditions were obtained. The optimum conditions of catalytic pyrolysis of LDPE over Al-MCM-41 （Si/Al=40） were reaction temperature 420℃, catalyst/LDPE（mass ratio）=0. 02 and reaction time 70min.Under the optimum conditions, the conversion of LDPE was 97.1% and the yield of liquid products was 83. 6%.更多还原