乙苯和对二甲苯在EUO分子筛上吸附的蒙特卡罗模拟
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摘要
采用巨正则统计系综蒙特卡罗模拟方法研究了高温条件下,乙苯和对二甲苯在4种不同硅铝比EUO分子筛上的吸附行为,并结合工业样品的催化反应进行了验证。结果表明:对二甲苯在EUO分子筛内的吸附能略高于乙苯,对二甲苯主要吸附在直孔道内,而乙苯更多地吸附在侧笼内;Al原子产生的B酸位对吸附质的扩散具有阻滞作用,导致对二甲苯的吸附等温线出现更多的阶梯平台;在反应过程中,积炭导致的堵孔对对二甲苯的扩散影响更大,因此,副产物甲苯的生成比乙苯的转化衰减更快。
The adsorption behavior of ethyl benzene and para-xylene on four EUO zeolites with different Si/Al ratio was studied under high temperature conditions by means of the macro-canonical statistics ensemble Monte Carlo simulation and validated by the catalytic reaction of industrial samples.GCMC simulation shows that the adsorption energy of PX in EUO zeolite is slightly higher than that of EB;PX is mainly adsorbed in the straight pore channel,while EB is adsorbed in the side cage,the Bronsted acid produced by Al atom can block the diffusion of adsorbed mass,which leads to more ladder platform in the adsorption isotherm of PX;the blockage caused by carbon deposition has a greater effect on PX diffusion,so the generation of by-product toluene will decay more rapidly than that of ethylbenzene.
The adsorption behavior of ethyl benzene and para-xylene on four EUO zeolites with different Si/Al ratio was studied under high temperature conditions by means of the macro-canonical statistics ensemble Monte Carlo simulation and validated by the catalytic reaction of industrial samples.GCMC simulation shows that the adsorption energy of PX in EUO zeolite is slightly higher than that of EB;PX is mainly adsorbed in the straight pore channel,while EB is adsorbed in the side cage,the Bronsted acid produced by Al atom can block the diffusion of adsorbed mass,which leads to more ladder platform in the adsorption isotherm of PX;the blockage caused by carbon deposition has a greater effect on PX diffusion,so the generation of by-product toluene will decay more rapidly than that of ethylbenzene.
引文
[1]吴巍.芳烃联合装置生产技术进展及成套技术开发[J].石油学报(石油加工),2015,31(2):275-281
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[13]赵仁殿,金彰礼,陶志华,等.芳烃工学[M].北京:化学工业出版社,2001:158
[2]Guisnet M,Gnep N S,Morin S.Mechanisms of xylene isomerization over acidic solid catalysts[J].Microporous and Mesoporous Materials,2000,35/36:47-59
[3]康承琳,周震寰,吴巍,等.乙基环己烷在择形分子筛上的异构化反应[J].石油炼制与化工,2012,43(5):1-5
[4]阮迟,冯小兵,胡满生,等.低铂脱乙基型C8芳烃异构化催化剂的工业应用[J].石油炼制与化工,2013,45(2):64-68
[5]周震寰,贾树岩,张培贵,等.ZSM-5分子筛酸性修饰及探针分子表征[J].石油炼制与化工,2016,47(3):5-9
[6]戴厚良.芳烃生产技术展望[J].石油炼制与化工,2013,44(1):1-10
[7]周震寰,张爱军,胡维军,等.碳八芳烃异构化分子筛的酸性与反应分析[J].石油炼制与化工,2017,48(11):76-81
[8]康承琳,周震寰,冯小兵,等.ZSM-5分子筛酸性质对二甲苯异构化反应的影响[J].石油炼制与化工,2013,44(12):35-41
[9]胡家芬,蔡健健,黄月芳,等.二甲苯异构化催化剂的表面酸性及其催化活性[J].催化学报,1985,6(4):325-331
[10]孙晓岩,宋泓阳,项曙光.ZSM-5分子筛上氯乙酸和二氯乙酸吸附行为的蒙特卡罗研究[J].计算机与应用化学,2017,34(2):109-113
[11]丁雪,刘熠斌,杨朝合,等.FCC干气在ZSM-5分子筛中吸附的分子模拟及热力学分析[J].石油炼制与化工,2015,46(9):58-64
[12]Bauer F,Bilz E,Freyer A.C-14studies in xylene isomerization on modified HZSM-5[J].Applied Catalysis A:General,2005,289:2-9
[13]赵仁殿,金彰礼,陶志华,等.芳烃工学[M].北京:化学工业出版社,2001:158