Method for preparing low-carbon olefin with high selectivity by catalyzing synthesis gas by using heteroatom-doped molecular sieve

Abstract

The invention relates to a catalyst containing a heteroatom-doped molecular sieve and a method for preparing low-carbon olefin by directly converting synthesis gas. The catalyst is a composite catalyst; a component I and a component II are compounded together in a mechanical mixing manner; wherein the active ingredient of the component I is a metal oxide; the component II is the heteroatom-doped molecular sieve; the molecular sieve has a topological structure of CHA or AEI, skeleton atoms comprise Al, P, O and Si, and heteroatoms can be one or more than two of ions from divalent 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 the component I to the component II is in a range of 0.1-20 times. The reaction process has very high low-carbon olefin selectivity, the sum of the selectivity of low-carbon olefins including ethylene, propylene and butylene can reach 50-90%, meanwhile, the selectivity ofbyproduct methane is lower than 7%, and meanwhile, the method has a very good application prospect.

Description

technical field [0001] The invention belongs to the field of preparing low-carbon olefins from synthesis gas, and in particular relates to a method for preparing low-carbon olefins from synthesis gas with high selectivity by catalyzing synthesis gas doped with heteroatom molecular sieves. Background technique [0002] Low-carbon olefins refer to olefins with carbon atoms less than or equal to 4. Low-carbon olefins represented by ethylene and propylene are very important basic organic chemical raw materials. With the rapid growth of my country's economy, the supply of low-carbon olefins has been in short supply for a long time. At present, the production of low-carbon olefins mainly adopts the petrochemical route of cracking light hydrocarbons (ethane, naphtha, light diesel oil). Due to the increasing shortage of global oil resources and the long-term high price of crude oil, the development of low-carbon olefins industry only relies on oil The tubular cracking furnace proce...

AI Technical Summary

Problems solved by technology

In the above report, the catalyst uses metal iron or iron carbide as the active component, and the reaction follows the chain growth reaction mechanism on the metal surface, and the selectivity of the product low-carbon olefins is low, and the selectivity of C3-C4 olefins is even lower

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