苯酚对SAPO-34催化甲醇制烯烃(MTO)选择性和催化剂失活的影响

Effect of phenol on the product selectivity and catalyst deactivation of SAPO-34 catalyzed methanol to olefin(MTO) process

甲醇制低碳烯烃(MTO)过程中,乙烯和丙烯容易进一步发生氢转移等二次反应,不但影响低碳烯烃的选择性,而且加速催化剂的积炭失活。在甲醇进料中加入苯酚,配制成w(苯酚)=0.5%的苯酚-甲醇溶液,发现加入苯酚后乙烯、丙烯和总烯烃的选择性可分别提高约2%、1.2%和2.5%,热重分析显示使用后催化剂孔腔内的积炭量有所下降。苯酚的加入有利于抑制烯烃进入催化剂孔腔发生二次反应,从而提高了烯烃的选择性且减缓了催化剂的失活。

Secondary reactions of ethylene and propylene in methanol to olefin（MTO）process will reduce the selectivity of olefins as well as accelerate the coke formation and deactivation.In this work,0.5% phenol is added to methanol.It is found that the addition of phenol increases the selectivity of ethylene,propylene and total olefins for about 2%,1.2% and 2.5%,respectively.Thermogravimety analysis of used catalyst indicated that phenol can reduce the coke formation in catalyst pore.It was proposed that phenol prevents olefins from entering SAPO-34 pore and secondary reaction of olefin is inhibited.Thereby,olefin selectivity is improved and catalyst deactivation is slow down.