铝改性ZSM-5分子筛催化剂对甲醇制汽油反应性能的影响研究
发布时间：2019-05-28 05:27
【摘要】：非石油路线,煤基甲醇制汽油技术(MTG)是应对石油资源日渐枯竭的重要手段之一,结合我国富煤、贫油、少气的现状,MTG技术在我国具有非常重要的现实意义。本文以铝离子改性的ZSM-5为催化剂,利用XRD、SEM和NH3-TPD等手段对催化剂的结构物性进行表征。ZSM-5分子筛在离子改性过程中的分子筛骨架没有遭到明显破坏。对通过水热法合成的Na-ZSM-5进行改性后得到具有一定B酸位或L酸位分子筛催化剂。对于商业ZSM-5分子筛,铝离子在不同的溶液(在水或者乙醇溶液中)中对分子筛离子交换程度具有明显影响。铝离子乙醇溶液更容易使铝离子进入ZSM-5分子筛孔道。本文以固定床为反应装置,研究了催化剂中B酸和L酸在MTG反应中的作用,并对商业H-ZSM-5分子筛在不同铝离子溶液(水或乙醇溶液)中进行改性,模拟催化剂再生后骨架脱铝过程,研究不同铝离子溶液对催化剂离子交换程度的影响和非骨架铝对MTG反应性能的影响。并探讨MTG反应的最优工艺。通过研究实验室合成且改性后的ZSM-5分子筛催化剂对MTG反应性能的影响,发现在一定范围内增加ZSM-5催化剂中的B酸浓度或强度可以提高其反应活性,且ZSM-5催化剂中的B酸和L酸在MTG反应中存在协同关系,Al-Z-0.4M-2f催化剂的寿命最长(43.3 h),C5+烃类选择性最高(57%以上)。通过分析不同硅铝比、不同L酸含量的商业ZSM-5分子筛在MTG反应中的反应活性,发现在商业H-ZSM-5分子筛中,增加L酸含量会降低其在MTG反应中的催化性能。在Al-Z-12.5-E系列催化剂中,L酸增加2.1倍,该催化剂的C5+烃类选择性降低为原来的0.6倍。由于一般商业ZSM-5催化剂本身就含有大量缺陷位,只需在催化剂孔道加入少量铝L酸,催化剂在MTG反应中的反应活性就会出现显著下降。所以商业ZSM-5催化剂在工业应用中的再生过程应尽量避免骨架铝的脱除。
[Abstract]:Non-petroleum route, coal-based methanol gasoline technology (MTG) is one of the important means to deal with the depletion of oil resources. Combined with the present situation of rich coal, poor oil and less gas in our country, MTG technology has very important practical significance in our country. In this paper, the structure and physical properties of the catalyst were characterized by XRD,SEM and NH3-TPD using aluminum ion modified ZSM-5 as catalyst. The molecular sieves skeleton of ZSM-5 molecular sieves was not obviously destroyed in the process of ion modification. Na-ZSM-5 synthesized by hydrothermal method was modified to obtain molecular sieves with certain B acid site or L acid site. For commercial ZSM-5 molecular sieves, aluminum ions have obvious effects on the ion exchange degree of molecular sieves in different solutions (in water or ethanol solution). Aluminum ion ethanol solution makes aluminum ion enter ZSM-5 molecular sieve channel more easily. In this paper, the role of B acid and L acid in MTG reaction was studied in a fixed bed reactor, and the commercial H-ZSM-5 molecular sieves were modified in different aluminum ion solutions (water or ethanol solutions). The effects of different aluminum ion solutions on the ion exchange degree of the catalyst and the effect of non-skeleton aluminum on the performance of MTG reaction were studied by simulating the process of skeleton dealumination after catalyst regeneration. The optimal process of MTG reaction was also discussed. By studying the effect of ZSM-5 molecular sieve catalyst synthesized and modified in laboratory on the performance of MTG reaction, it is found that the activity of ZSM-5 catalyst can be improved by increasing the concentration or strength of B acid in the catalyst in a certain range. There is a synergistic relationship between B acid and L acid in ZSM-5 catalyst in MTG reaction, and the lifetime of Al-Z-0.4M-2f catalyst is the longest (43.3 h), C5 hydrocarbon selectivity is the highest (more than 57%). By analyzing the reaction activity of commercial ZSM-5 molecular sieves with different Si / Al ratio and different L acid content in MTG reaction, it was found that increasing L acid content in commercial H-ZSM-5 molecular sieves would decrease the catalytic performance of commercial H-ZSM-5 molecular sieves in MTG reaction. In Al-Z-12.5-E series catalysts, L acid increased by 2.1 times, and the C 5 hydrocarbon selectivity of the catalyst decreased to 0.6 times as much as that of the original catalyst. Because the commercial ZSM-5 catalyst itself contains a large number of defect sites, the activity of the catalyst in MTG reaction will decrease significantly with the addition of a small amount of aluminum and L acid into the catalyst pore. Therefore, the regeneration process of commercial ZSM-5 catalyst in industrial application should avoid the removal of skeleton aluminum as far as possible.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE665
本文编号：2486773
[Abstract]:Non-petroleum route, coal-based methanol gasoline technology (MTG) is one of the important means to deal with the depletion of oil resources. Combined with the present situation of rich coal, poor oil and less gas in our country, MTG technology has very important practical significance in our country. In this paper, the structure and physical properties of the catalyst were characterized by XRD,SEM and NH3-TPD using aluminum ion modified ZSM-5 as catalyst. The molecular sieves skeleton of ZSM-5 molecular sieves was not obviously destroyed in the process of ion modification. Na-ZSM-5 synthesized by hydrothermal method was modified to obtain molecular sieves with certain B acid site or L acid site. For commercial ZSM-5 molecular sieves, aluminum ions have obvious effects on the ion exchange degree of molecular sieves in different solutions (in water or ethanol solution). Aluminum ion ethanol solution makes aluminum ion enter ZSM-5 molecular sieve channel more easily. In this paper, the role of B acid and L acid in MTG reaction was studied in a fixed bed reactor, and the commercial H-ZSM-5 molecular sieves were modified in different aluminum ion solutions (water or ethanol solutions). The effects of different aluminum ion solutions on the ion exchange degree of the catalyst and the effect of non-skeleton aluminum on the performance of MTG reaction were studied by simulating the process of skeleton dealumination after catalyst regeneration. The optimal process of MTG reaction was also discussed. By studying the effect of ZSM-5 molecular sieve catalyst synthesized and modified in laboratory on the performance of MTG reaction, it is found that the activity of ZSM-5 catalyst can be improved by increasing the concentration or strength of B acid in the catalyst in a certain range. There is a synergistic relationship between B acid and L acid in ZSM-5 catalyst in MTG reaction, and the lifetime of Al-Z-0.4M-2f catalyst is the longest (43.3 h), C5 hydrocarbon selectivity is the highest (more than 57%). By analyzing the reaction activity of commercial ZSM-5 molecular sieves with different Si / Al ratio and different L acid content in MTG reaction, it was found that increasing L acid content in commercial H-ZSM-5 molecular sieves would decrease the catalytic performance of commercial H-ZSM-5 molecular sieves in MTG reaction. In Al-Z-12.5-E series catalysts, L acid increased by 2.1 times, and the C 5 hydrocarbon selectivity of the catalyst decreased to 0.6 times as much as that of the original catalyst. Because the commercial ZSM-5 catalyst itself contains a large number of defect sites, the activity of the catalyst in MTG reaction will decrease significantly with the addition of a small amount of aluminum and L acid into the catalyst pore. Therefore, the regeneration process of commercial ZSM-5 catalyst in industrial application should avoid the removal of skeleton aluminum as far as possible.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE665
【共引文献】
相关期刊论文 前2条
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相关硕士学位论文 前3条
1 葛兰英;磷化废水的资源化处理及原位合成多孔磷酸盐的研究[D];上海大学;2013年
2 何静宇;HZSM-5催化剂上甲醇芳构化研究[D];北京化工大学;2014年
3 周国强;改性ZSM-5分子筛催化热解生物质研究[D];清华大学;2014年
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