甲醇转化ZSM-5催化剂成型技术研究进展

Research progress in the molding techniques of ZSM-5 catalysts for methanol conversion

ZSM-5粉状分子筛通过成型被应用于固定床甲醇转化反应器中,成型技术有压片成型法、挤条成型法和干胶转化法。压片成型法保持了ZSM-5的原有性能,但是不适合工业化的需要。挤条成型法在工业中应用广泛,但ZSM-5的物化性能与粘结剂的成分和用量有着较大的联系,通常Al_2O_3会引入大量的L酸,同时造成比表面积减小;SiO_2成型对ZSM-5的酸性和酸量影响不大,但会导致表面积减少;磷铝粘结剂在成型过程中会形成稳定的磷铝晶体,不但能保持原催化剂的物化性能,还形成了利于产物传送的大孔。干胶转化法在保持原催化剂物化性能的情况下,具有节能环保等优点,具有广泛的应用前景。

For use in the fixed bed reactor as catalyst for methanol conversion, ZSM-5 molecular sieve powder should be molded, and the molding techniques include compression, extrusion and dry gel conversion methods. The compression molding method could maintain the original catalytic performance of ZSM-5, but it is not suitable for industrial production. The extrusion molding method is widely applied in industry, but the physical and chemical properties of ZSM-5 shaped are significantly affected by the composition and dosage of binder. Usually, the binder A1203 introduces a large number of Lewis acid to the catalyst and reduces its specific surface area; the binder SiO2 has little impact on the amount and kind of acid; and the binder phosphorus aluminum could form stable crystals in the process of molding, which can keep the original physicochemical properties of catalyst and form macropores that benefit the diffusion of macromoleculars. Dry gel conversion method not only could maintainin the physical and chemical properties of the original catalyst, but also is energy saving and environmentally friendly, showing a good application