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 present invention relates to a method for reusing coal gas at the outlet of a direct reduction process using coal gas as reducing gas, in particular to a CO2 in the export gas of a direct reduction process using coal gas as reducing gas 2 method of reuse. Background technique [0002] China is rich in coal resources. Compared with the blast furnace process, the direct reduction process using non-coking coal gas as the reducing gas can save investment in coking, sintering and other processes, and 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 gas preparation system, a gas treatment system and a direct reduction device. The reduced gas produced by the high-carbon carrier in the gas preparation system enters the gas treatment system for treatment, and the treated gas enters the direct reduction device to produce direct...

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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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