METHOD FOR THE PREPARATION OF LOW-CARBON OLEFIN IN HIGH SELECTIVITY FROM SYNTHESIS GAS CATALYZED BY HETEROATOM-DOPED MOLECULAR SIEVE

摘要

Disclosed are a catalyst comprising a heteroatom-doped molecular sieve and a method for preparing a low-carbon olefin by direct conversion of synthesis gas. The catalyst is a complex catalyst comprising component I and component II complexed together by means of mechanical mixing. The active ingredient of component I is a metal oxide, and component II is a heteroatom-doped molecular sieve, the molecular sieve having a topological structure of CHA or AEI. The skeleton atom comprises Al-P-O or Si-Al-P-O, and the heteroatom can be one of, or two or more of divalent metal Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Mo, Cd, Ba, Ce, trivalent Ti, Ga, and tetravalent Ge. The weight ratio of the active ingredient of component I to component II is from 0.1 to 20. The reaction process has a high selectivity for low-carbon olefins, with a summed selectivity of 50% to 90% for low-carbon olefins comprising ethylene, propylene and butylene, and has a low selectivity of below 7% for methane as a byproduct. The catalyst and the method thus has favorable prospects for application.