摘要
在等温固定床反应器中考察了460℃、甲醇分压20kPa下H-ZSM-5分子筛催化剂上甲醇分别和4倍CH2质量的C4=、C5=或C6=共反应时芳烃、C1～C4烷烃和乙烯收率随空时的变化关系。芳烃、C2～C4烷烃的收率随空时呈近似线性增加;乙烯收率随空时缓慢增加至热力学平衡。相同空时下,芳烃、C2～C4烷烃和乙烯的收率均不随进料烯烃种类变化;丙烯、C4～C6烃的质量分数受进料烯烃种类影响很小。实验结果表明,甲醇和C4～C6烯烃共反应制丙烯时,随着空时的增大,甲醇和C4～C6烯烃先经甲基化裂化反应生成具有相对稳定分布的C3～C6烯烃;后者再经叠合和裂化反应生成乙烯并同时经烯烃氢转移反应生成芳烃和烷烃。
The yields of aromatics,C1—C4 paraffins and ethylene at varying space time and at methanol partial pressure of 20 kPa in co-reaction of methanol and butene,pentene or hexene were investigated over H-ZSM-5 catalyst in an isotherm fixed-bed reactor at 460℃.For each feed,the CH2 mass ratio of alkenes to methanol was 4.It was found that individual yields of aromatics and C2—C4 paraffins showed linear dependence on space time while ethylene yield increased slowly with space time up to thermodynamic equilibrium.It was also found that at constant space time individual yields of aromatics,C2—C4 paraffins and ethylene did not rely on feed composition.Only slight dependence of mass fraction on feed composition was observed for propylene,C4,C5 and C6,respectively.These results indicated that in co-reaction of methanol and butene,pentene or hexene,a mixture of C=3—C=6 with relatively steady distribution was first formed through methylation of C=4—C=6 followed by cracking of C=6 and C=7.Ethylene was formed subsequently through oligomerization and cracking of the C=3—C=6 mixture to reach thermodynamic equilibrium composition.Aromatic products,mainly toluene,xylenes and tri-methylbenzenes,were assumed to be formed through aromatization of C7 and C8 olefins along with formation of paraffins through hydrogen transfer reactions.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2012年第2期493-499,共7页
CIESC Journal
关键词
甲醇
丙烯
乙烯
MTP
副产物
methanol
propylene
ethylene
MTP
by-product
