System and method for preparing reducing gas through lignite double-bed gasification

Abstract

The invention provides a system and a method for preparing reducing gas through lignite double-bed gasification. The system comprises a combustion furnace, a gasification furnace, a gas solid separator, a material return device, a catalyst tank and a pulverized coal mixing device; the combustion furnace is provided with a flue gas outlet, a semi-coke / ash inlet, an ash residue outlet and an air inlet; a gasifying agent distribution plate, a semi-coke collecting plate and a catalyst supporting plate are arranged in the gasification furnace; a semi-coke / ash outlet, a semi-coke outlet, a catalyst inlet and a feeding port are formed in the side wall of the gasification furnace; the semi-coke / ash outlet is connected with the semi-coke / ash inlet through the material return device; the semi-coke outlet is connected with a catalyst inlet of the catalyst tank; the catalyst inlet is connected with a catalyst outlet of the catalyst tank; and the feeding port is connected with a discharging port of the pulverized coal mixing device. By utilization of the system, the reducing gas can be prepared from the lignite, and the reducing gas can be applied to a gas-based shaft furnace to perform direct reduction iron making without needing a conversion device to adjust gas components.

Description

technical field [0001] The invention relates to a lignite gasification technology, in particular to a system and a method for efficiently producing metallurgical reduction gas, coal gas and synthesis gas by double-bed gasification of lignite. Background technique [0002] The modern ironmaking process based on the blast furnace has been developed to a very perfect level, but there are disadvantages such as long process, large investment, use of coke, and serious environmental pollution. Compared with oil and natural gas, although my country is rich in coal resources, coking coal only accounts for 37%, of which main coking coal only accounts for 6%, and the distribution is uneven. This determines that the ironmaking technology that consumes a large amount of coking coal is unsustainable. Direct reduction ironmaking uses coal, gas or liquid fuel as the energy source and reducing agent. Below the softening temperature of the iron ore, it does not melt and reduces the iron oxid...

AI Technical Summary

Problems solved by technology

The current mature gasification process: CO>H in the gas composition produced by fixed bed, fluidized bed and entrained bed 2 , none of the existing coal gasification processes can directly provide gas components that meet the requirements, and all of them need to be equipped with a CO shift device to increase the H 2 This method generally has the disadvantages of high gasifier pressure, high gas production cost, and high energy consumption.

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