用于MTO装置中的乙炔选择加氢催化剂研究

Research on Selective Hydrogenation Catalyst for Acetylene in MTO Units

在MTO工艺装置生产乙烯的过程中,乙烯中常含有50~200μL/L左右的微量乙炔,现有的石油烃蒸汽裂解制乙烯装置中常用的碳二加氢催化剂或适用于微量乙炔选择加氢的乙烯精制催化剂并不是MTO工艺中乙炔选择加氢的最好选择。通过研究Pd含量变化对催化剂性能的影响,发现降低Pd含量能够提高催化剂的乙烯选择性,降低催化剂的乙炔合格温度,在保证乙炔加氢合格的情况下,通过控制较低的氢炔比还能获得更好的乙烯选择性。通过添加适当的助剂,控制助剂的用量也能够提高催化剂的乙烯选择性。和商业碳二加氢催化剂BC2相比,采用浸渍法制备的BC2-MTO催化剂活性组分Pd含量降低了50%以上,活性金属Pd的分散度提高了69%,能够在较低的反应温度和氢炔比条件下使用,具有更好的催化活性和乙烯选择性。

During the production of ethylene in MTO unit,the ethylene often contains about 50~200μL/L trace acetylene.Neither the C2 hydrogenation catalyst commonly used in petroleum hydrocarbon steam cracking unit for ethylene production nor the ethylene refining catalyst suitable for selective hydrogenation of trace acetylene is the best choice for the selective hydrogenation of acetylene in MTO process.By studying the ef fect of Pd content on catalyst performance,it is found that reducing Pd content can improve the ethylene se lectivity of catalyst and reduce the temperature at which acetylene is completely removed.Under the condition of ensuring up-to-standard acetylene hydrogenation,better ethylene selectivity can be obtained by controlling a lower hydrogen-acetylene ratio.By adding appropriate additives,controlling the amount of additives can also improve the ethylene selectivity of catalyst.The active component Pd content of BC2-MTO catalyst prepared by impregnation method is reduced by more than 50%and the dispersion of active metal Pd is increased by 69%compared with those of the commercial C2 hydrogenation catalyst BC2.BC2-MTO catalyst can be used at lower reaction temperature and hydrogen-acetylene ratio,and has better catalytic activity and ethylene se lectivity.