Preparation method and application of alkali metal modified tin dioxide catalyst for methane oxidative coupling

Abstract

The invention provides a preparation method and application of an alkali metal modified tin dioxide catalyst for methane oxidative coupling. The preparation method comprises the following steps: regulating the pH (Potential of Hydrogen) value of a tin chloride pentahydrate water solution to 7 by utilizing ammonia water with the mass percent of 25 percent to 28 percent until Sn<4+> ions are completely precipitated; then carrying out suction filtering and washing with de-ionized water until TDS (Total Dissolved Solids) is less than 10; then drying and roasting to obtain an SnO2 carrier; and adding the SnO2 carrier into a proper amount of alkali metal nitrate solution and drying and roasting to prepare the catalyst with the mol ratio of n(M) to n(Sn) of x to (10-x), wherein M is Li, Na, K orCs. The catalyst prepared by the preparation method provided by the invention has good low-temperature performance and stability in reaction for preparing ethane and ethylene by simulating the methaneoxidative coupling. The preparation method takes cheap metal salt as a raw material and the related catalyst is prepared by adopting an equal-volume immersion method. The catalyst has the advantagesof low production cost, simple synthesis technology, easiness of controlling a synthesis process and the like.

Description

Technical field [0001] The invention belongs to the technical field of energy catalysis, and relates to a preparation method of an alkali metal modified tin dioxide catalyst used for methane oxidative coupling reaction to directly convert cheap methane into ethylene and ethane products with high economic and industrial value. Background technique [0002] The global oil resources are increasingly scarce, and the unclean use of energy by humans has led to increasingly serious environmental pollution. In the face of increasingly severe energy and environmental crises, the development of green new energy is extremely urgent. Methane is the main component of natural gas. Compared with other petrochemical energy sources such as coal and oil, it is cleaner and has abundant reserves. The use of methane as a raw material to synthesize high-value chemicals such as methanol and ethylene has always been a research hotspot among scientists around the world. The effective utilization of met...

AI Technical Summary

Problems solved by technology

For these catalysts, there are the following problems: the reaction temperature is high and must be carried out at 700-900 ° C; methane single-pass conversion rate and C 2 low yield

Chinese patent CN1061730A discloses a catalyst composed of thorium oxide, lanthanum oxide, and barium carbonate, but when a high methane conversion rate is reached at a high temperature of 780-900 ° C 2 less selective

Chinese patent CN1145824A discloses a Sm-Li / MgO catalyst, which has better methane conversion rate and stability at a high temperature of 800 °C, but C 2 Product selectivity and C 2 Product yield is low

Chinese patent CN101138720A discloses a metal-based monolithic catalyst, which has a good conversion rate of methane at a high temperature of 820°C, but the catalyst components are complicated, and the synthesis process is cumbersome and C 2 Product selectivity and C 2 Product yield is low

Due to the C of all catalysts so far 2 Yield all can't reach more than 30%, be difficult to realize industrialization

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