正戊烷芳构化生成丙烷反应路径及其工艺条件

Reaction Path and Process Conditions of Aromatization of n-Pentane to Produce Propane and Aromatics

选取3种不同硅/铝摩尔比的HZSM-5分子筛为正戊烷芳构化反应的催化剂,并对硅/铝摩尔比为90的分子筛进行锌改性制备改性催化剂,对几种催化剂进行吡啶-红外表征和NH 3程序升温脱附表征,考察了正戊烷在各催化剂上的芳构化反应性能。结果表明:正戊烷主要在催化剂表面B酸中心上发生质子化裂解和氢转移反应生成丙烷,锌改性HZSM-5催化剂表面B酸量减少,不利于提高丙烷收率;在温度为420℃、进料质量空速为0.5 h^-1、反应压力为0.5 MPa的条件下,正戊烷在硅/铝摩尔比为30的HZSM-5催化剂上反应可以得到57.57%的丙烷和11.95%的芳烃收率。

Three different silicon/aluminum molar ratios of HZSM-5 molecular sieves were selected as catalysts,and the molecular sieve with silicon/aluminum molar ratio of 90 was zinc-modified.The prepared catalysts were then characterized by pyridine-infrared spectrum and NH 3 temperature programmed desorption.The aromatization reaction of n-pentane on the two groups of catalysts was also investigated.Experimental results indicate that n-pentane mainly undergoes protonation cracking and hydrogen transfer reaction on the B acid center of the catalyst to form propane.Low amount of B acid on the surface of zinc-modified HZSM-5 catalyst is not good to increase propane yield.At temperature of 420℃,mass hourly space velocity of 0.5 h-1 and reaction pressure of 0.5 MPa,n-pentane can obtain 57.57% propane yield and 11.95% aromatic yield by reacting on HZSM-5 with a molar ratio of silica to aluminum of 30.