摘要
用氧化硅为载体、高硅铝比的ZSM-5分子筛为活性组分,挤条成型制成催化剂,用碱土金属和稀土金属氧化物改性,在600℃、常压下、水重时空速为1 h-1的条件下进行预处理24 h,分别在485℃、0.1 MPa、水/C4质量比为0.2、C4重时空速为3 h-1的条件下和无水稀释、C4重时空速为10 h-1的条件下,C4烯烃制丙烯和乙烯的反应产物组成稳定;在连续20天的反应过程中,C4烯烃转化率大于65%;有水稀释时丙烯收率大于31%、乙烯收率大于6%、催化剂的积炭量为1.01%,无水稀释时丙烯收率大于27.5%、乙烯收率大于4.6%、催化剂的积炭量为4.71%。对有水工艺和无水工艺再生后的催化剂作用BET、NH3-TPD和Py-IR进行表征,分析催化剂活性与酸性的关系,认为催化剂表面B酸的酸量和强度与催化剂的活性相关。
With silicon oxide as carrier,a catalyst with ZSM-5 molecular sieve with high ratio of n（SiO2）/n（Al2O3） as the active component was prepared for the preparation of propylene and ethylene from C4 alkenes by catalytic cracking.The precursors of alkali earth and rare earth metal oxides were used to adjust the acidic property of the catalyst.The catalyst was pretreated with steam for 24 h under these conditions of 600 ℃,atmospheric pressure and water weight hourly space velocity（WHSV）1 h-1.At 485 ℃,0.1MPa,w（H2O）∶w（C4=）=0.2/0,WHSV 3 h-1,as well as at WHSV 10 h-1 without water dilution,the conversion of C4 alkenes was more than 65% in a 20 day-long reaction process.The yields of propylene and ethylene were more than 31% and 6%,and the amount of carbon deposition on the catalyst was 1.01% using water as diluent in the reaction system.While the yields of propylene and ethylene were more than 27.5% and 4.6%,and the amount of carbon deposition on the catalyst was 4.71% without using water as diluent.The catalysts were characterized by BET,NH3-TPD and Py-IR.The results showed that the catalytic activity depended on the amount of B acid of the catalyst.
出处
《化工进展》
EI
CAS
CSCD
北大核心
2011年第3期530-535,541,共7页
Chemical Industry and Engineering Progress
