Recycling method of outlet gas in direct reduction process using gas as reducing gas

Abstract

The invention discloses a recycling method of outlet gas in a direct reduction process using gas as reducing gas, in particular to a method for recycling CO2 in outlet gas in a direct reduction process using gas as reducing gas. The method comprises the following treating steps: after outlet gas of a direct reduction device is treated by an outlet gas treating system of the direct reduction device, the outlet gas enters a CO2 separating system for decarburization treatment to obtain CO2 enriched desorption gas and CO+H2 enriched decarburizing gas, wherein after the CO2 enriched desorption gasis treated by a treating system of the CO2 enriched desorption gas, and the CO2 enriched desorption gas is sent back to a gas preparing system or the CO2 enriched desorption gas used as a transport carrier of direct reduction iron, high-carbon carrier or dust is sent back to the gas preparing system. The method achieves the purpose of CO2 emission reduction, also reduces the quantity of consumed coal required by reducing iron ore per unit mass and saves the cost.

Description

Technical field [0001] The invention relates to a method for reusing the outlet gas of a direct reduction process using coal gas as a reducing gas, in particular to a method of using coal gas as a reducing gas for CO in the outlet gas of a direct reduction process 2 Reuse method. Background technique [0002] China is rich in coal resources. Compared with the blast furnace process, the direct reduction process that uses coal gas made from non-coking coal as reducing gas can save the investment in coking and sintering processes. Waste gas (especially CO 2 ), less waste discharge, and the cost of coal for gas production is much lower than that of coke. The direct reduction process system usually includes a coal gas preparation system, a coal gas treatment system and a direct reduction device. Using the reduced gas produced by the high-carbon carrier in the coal gas preparation system, the produced coal gas enters the coal gas processing system for processing, and the processed coal...

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Problems solved by technology

[0004] The above (1) and (2) processes have not considered how to treat CO 2 (3) CCID Engineering Technology Co., Ltd. proposes to use CO 2 Purified and pressurized as a recycling method for pulverized coal as a conveying medium, but the process is complicated and the CO 2 The operating cost of the purification process is too high

[0005] To sum up, at present, the direct reduction process using coal gas as reducing gas at home and abroad has a significant impact on CO 2 There is very little consideration for reuse, and even if it is considered, the investment and operating costs are high

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