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通过浸渍或交换的方法,对ZSM-5型沸石进行改性,以调节沸石的表面酸性及孔道大小,从而提高甲醇转化为低碳烯烃的选择性。改质剂采用Ba、Ca、Sr、La、Mg、Y、Zr、Ti、Al、W、Sb等元素,发现生成低碳烯烃的选择性和元素的电负性之间存在一定的关系,电负性在1.1—1.5之间的金属元素改质的催化剂,选择生成C_2~=—C_4~=最佳。考察了单组份改质剂中加入第二组份以及粘合剂制备的复合型催化剂的反应性能。结果表明,通过Mg和TiO_2改性的催化剂,甲醇转化烃类产物中C_2~=—C_4~=烯烃可达96％,其中丙烯达68％;Al改性的沸石上C_2~=—C_4~=烯烃为74.4％,其中乙烯和丙烯含量相应为41.2和33.2w％。
The ZSM-5 zeolite is modified by impregnation or exchange to adjust the surface acidity and pore size of the zeolite, thereby increasing the selectivity of methanol to light olefins. The modifier uses elements such as Ba, Ca, Sr, La, Mg, Y, Zr, Ti, Al, W and Sb and found that there is a certain relationship between the selectivity for the formation of light olefins and the electronegativity of the element. Negative in the 1.1-1.5 metal elements between the modified catalyst, choose to generate C_2 ~ = -C_4 ~ = the best. The reaction performance of the composite catalyst prepared by adding the second component and the binder into the single component modifier was investigated. The results showed that the amount of C_2 ~ = -C_4 ~ = olefins in methanol conversion reached 96%, of which propylene reached 68%. The amount of C_2 ~ = -C_4 ~ = The olefin is 74.4%, with the ethylene and propylene contents corresponding to 41.2 and 33.2 w% respectively.