国内乙烯装置丙烯加氢精制工艺研究进展

石油烃裂解分离的碳三(C3)馏分催化选择加氢脱丙炔(MA)和丙二烯(PD)是工业上乙烯装置丙烯精制以制备聚合级丙烯的方法.碳三催化选择加氢工艺有气相、液相(包括气-液相)和催化精馏三种类型,其中以液相工艺应用最广,催化精馏工艺未见工业化报道.综述了近年来国内在碳三加氢反应动力学、加氢工艺及催化剂失活和再生方面取得的进展.动力学研究表明,丙炔和丙二烯的加氢速率与其浓度和氢气的分压成正比关系,而丙烯的加氢速率则仅与氢气的分压有关.国内碳三液相加氢工艺和催化剂不仅在国内装置上应用,而且已经出口国外.除了砷、一氧化碳和水是导致催化剂失活的原因以外,碳三馏分中的碳四组分浓度也是造成加氢催化剂失活的主要原因之一.采用低温空气氧化法取代传统的蒸汽-空气法实现催化剂再生具有再生周期长等优点.

Advances in Technologies for Hydrofining Propylene in Ethylene Units

Catalysis and selective hydrogenation of C3 distillate from petroleum hydrocarbon cracking to remove methylacetylene(MA) and propadiene(PD) is an industrial method used for producing polymerization-grade propylene by refining process in ethylene units.There are three types of C3 catalysis and selective hydrogenation technologies-gas phase,liquid phase(including gas-liquid phase) and catalytic distillation.Liquid phase technology is the most commonly used.No report has been heard of the commercialization of the catalytic distillation technology.This article summarizes the advances in C3 hydrogenation dynamics,hydrogenation technology and catalyst deactivation and regeneration in China.Dynamics studies show that the hydrogenation rates of MA and PD are directly proportional to their concentrations and hydrogen pressure and that the hydrogenation rate of propylene is only related to hydrogen pressure.Domestically developed C3 liquid-phase hydrogenation technology and catalysts are not only being used in domestic units but have also been exported.In addition to arsenic,carbon monoxide and water,C4 component in C3 distillate is also a major cause of catalyst deactivation.Using the low-temperature air oxidation method to replace the conventional steam-air method in catalyst regeneration has many benefits including longer regeneration cycles.