异丁烷循环促进离子液体[Et_(3)NH]Cl-AlCl_(3)催化正庚烷异构化反应  

NORMAL HEPTANE ISOMERIZATION CATALYZED BY IONIC LIQUID[Et_(3)NH]Cl-AlCl_(3) PROMOTION BY CIRCULATION OF ISOBUTANE

作　　者：王鹏军 刘浩玮 郑涛 张睿[1] 孟祥海[1] 刘海燕[1] 刘植昌[1] Wang Pengjun;Liu Haowei;Zheng Tao;Zhang Rui;Meng Xianghai;Liu Haiyan;Liu Zhichang(State Key Laboratory of Heavy Oil Processing,China University of Petroleum,Beijing 102249)

机构地区：[1]中国石油大学(北京)重质油全国重点实验室,北京102249

出　　处：《石油炼制与化工》2024年第6期9-17,共9页Petroleum Processing and Petrochemicals

基　　金：国家自然科学基金资助项目(22021004)。

摘　　要：轻烃异构化一般以C_(5)和C_(6)烃为原料,C_(7)及C_(7)以上烃类在异构化过程中由于存在较为剧烈的裂化反应,致使异构化油收率较低。作为一种新型低温轻烃异构化催化剂,离子液体对大分子烃类原料的适应性不佳。因此,在大分子烃类异构化过程中,抑制副反应、提高异构化油收率一直是研究的难点和重点。基于离子液体催化烷烃异构化反应机理,通过异丁烷循环抑制副反应、促进异构化反应的进行,进而降低异构化产物中C_(4)烷烃的含量,提高异构化油的收率。系统考察了异丁烷引入量、反应温度、反应时间、搅拌速率以及酸烃比等工艺条件对氯铝酸离子液体催化正庚烷异构化反应的影响规律。结果表明,体系中大量异丁烷的循环提高了氢转移速率,抑制了裂化、歧化等副反应,使副产物C 4组分的含量大幅降低。在异丁烷引入量为正庚烷体积的30%、反应温度为50℃、反应时间为1 h、搅拌速率为1500 r min和酸烃比(离子液体与正庚烷体积比)为1的条件下,正庚烷转化率达到91.0%,异构烷烃选择性和液体收率分别达到87.2%和93.5%;与未引入异丁烷体系相比,正庚烷转化率相近时,引入异丁烷体系的异构烷烃选择性和液体收率分别提高了16.0百分点和14.8百分点。Light hydrocarbon isomerization usually takes C_(5) and C_(6) hydrocarbons as feedstocks,and C_(7)+hydrocarbons in the process of isomerization are prone to a relatively severe cracking reaction,resulting in low yield of isomerized oil.As a novel low-temperature catalyst,ionic liquid has also poor adaptability to macromolecular hydrocarbon feedstocks.Therefore,in the process of macromolecular hydrocarbon isomerization,inhibiting side reaction and improving the yield of isomerized oil during the isomerization of larger hydrocarbons have been the difficulty and focus of research.Based on the mechanism of the alkane isomerization catalyzed by ionic liquid,isobutane circulation can inhibit side reaction and promote the isomerization reaction,which served to reduce the content of C_(4) alkanes in the isomerization product and increase the yield of isomerized oil.The influence of process conditions such as the addition amount of isobutane,reaction temperature,reaction time,stirring rate and acid-to-alkane ratio on the n-heptane isomerization catalyzed by chloroaluminate ionic liquid was systematically studied.The results showed that the circulation of isobutane significantly decreased the yield of the by-product C_(4) components.The reason was that the substantial presence of isobutane in the system could significantly accelerate the rate of hydrogen transfer during the reaction,effectively inhibit the secondary reactions such as cracking and disproportionation.Under the conditions of an isobutane dosage of 30%,a reaction temperature of 50℃,a reaction time of 1 h,a stirring speed of 1500 r min and an acid-to-alkane ratio of 1,the n-heptane conversion reached 91.0%,with isomeric hydrocarbon selectivity and liquid yield of 87.2%and 93.5%,respectively.Compared to those of the reaction system without isobutane,the isomeric hydrocarbon selectivity and liquid yield of the reaction system with isobutane at similar conversion rate of n-heptane increased by 16.0 percentage points and 14.8 percentage points,respectively.

关 键 词：异构化 离子液体 引发剂 异丁烷 正庚烷 

分 类 号：TE624[石油与天然气工程—油气加工工程]