摘要
丙烯歧化制乙烯与丁烯是调整烯烃生产结构,提供利用价值较高烯烃的有效过程。本文探讨了W-Si系催化剂中WO_3≥20%歧化催化剂的活性、选择性和稳定性。分析了反应温度、压力和空速的影响,利用此型催化剂可以提高催化活性,从而降低了所需的反应温度和操作压力。D—5催化剂在微型反应器中实验结果表明,T=275℃,P=0.883MPa,VHSV=1700hr^(-1)时,丙烯转化率X=38.8%,选择性S=97.3%,C_5^+=≤1.2%。D—4a催化剂在20ml小试反应器中进行稳定性试验,操作40小时,T=315~420℃,P=0.883MPa,VHSV=4000hr^(-1)时,X=41.0%,S=95.1%,C_5^+≤2.6%。催化剂再生性能良好,本文还讨论了不同温度下高钨含量催化剂在发生丙烯二聚,C_4^-异构化和二次歧化等副反应时对生成C_4-1及C_5^+的作用。
Propene-metathesis for manufacturing ethylene and butene is an effective process to adjust the productive structure of olefins in order to provide more valuable olefins. In this paper, we investigated the activity, selectivity and stability of W-Si series catalysts for disproportionation of propylene with WO3 more than/equal to 20% supported on silica. The influences of reaction temperature, pressure and space velocity for the reaction were studied. By virtue of higher content of supported-WO3 catalyst for propene metathesis, the catalytic activity may be improved and so the required reaction temperature and operation pressure may also ba lowered. Using No. D-5 catalyst in the micro-reactor, the experimental results were: when T=275℃, P = 0.83MPa, VHSV= 1700hr-1, the conversion of propene, x=38.8%, selectivity, s = 97.3% and C5 +≤1.2%. When No.D-4a catalyst was used in the 20ml. reactor to test for stability of the catalyst, operation lasted for 40 hours under the conditions: T=315-420℃, P=0.883MPa and VHSV=4000 hours-1, the average results were: x=41.0%, s=95.1% and C5 +≤2.6%. The regeneration property of the catalyst was good.Allso, in this paper, the roles played by the higher content of supported-WO3 catalyst for side-reactions such as dimerization of propylene, isomerization of butene and the secondary disproportionation to form butene-1 and C5+ were discussed.
关键词
丙烯
歧化
复分解
催化剂
氧化钨
Propene metathesis or disproportionation of Propylene, Catalyst,Tungstun-oxide