摘要
通过对丁烯催化裂解反应网络中各反应步骤进行热力学分析计算 ,结合实际反应的产物分布 ,探讨了各产物的形成机理及影响因素 .热力学计算结果表明 ,升高温度有利于丁烯裂解为丙烯和乙烯 ,选择合适的反应温度和压力可有效提高产物中的丙烯 /乙烯比 .低碳烯烃在热力学上有很强的芳构化倾向 ,升高温度可抑制氢转移反应 ,可以通过优化反应条件和开发高选择性催化剂的方法来提高丙烯和乙烯的选择性 ,抑制芳烃和烷烃的生成 .在催化裂解反应条件下 ,C5+ 烃的生成量较少 .热力学计算结果在进行催化剂筛选和反应条件优化过程中得到了验证和补充 .
By analyzing the reaction process and calculating the thermodynamics of each reaction in butene catalytic cracking combining the factual product distribution, the formation mechanism of each product and its influence factors have been studied. The calculated equilibrium constants showed that high temperature favored C4H8 cracking to C3H6 and C2H4, but relatively low temperature and high pressure were needed in order to increase the molar ratio of C3H6/C2H4 in the products. The equilibrium constants of alkene hydrogen transfer and oligomerization-dehydrocyclization-aromatization reaction were 10 similar to 1000 times as high as those of C4H8 cracking to C3H6, which implied that it was favorable to form aromatics and low carbon alkanes under the cracking conditions compared with C3H6 and C2H4 production. In order to suppress the formation of aromatics and low carbon alkanes dynamically, it was very important to develop catalysts with high selectivity for C3H6 and C2H4, and to optimize reaction conditions such as relatively high WHSV and high temperature. In the mean time, the amount of C5+ hydrocarbons was in a low level under the catalytic cracking conditions. The thermodynamics result was confirmed and supplemented by its application in catalyst design and reaction condition optimization during butene catalytic cracking to C3H6 and C2H4.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2005年第2期111-117,共7页
基金
国家自然科学基金 (2 0 3 0 3 0 19)
国家重点基础研究发展规划 (973计划 ) (2 0 0 3CB615 80 2 )资助项目 .
关键词
丁烯
催化裂解
丙烯
乙烯
热力学
ZSM-5
butene
catalytic cracking
propene
ethene
thermodynamics
ZSM-5 zeolite
