Method for producing gas-based directly reduced iron by utilizing non-catalytic conversion of coke-oven gas, and system thereof

Abstract

The invention relates to a method for producing gas-based directly reduced iron by utilizing the non-catalytic conversion of a coke-oven gas, and a system thereof. The method comprises the following steps: mixing the coke-oven gas obtained after routine purification and fine desulfurization treatment with a mixed gas comprising one or above two of a converter gas, a blast furnace gas and a purified tail gas to form a raw material gas mixture, and partially combusting the raw material gas mixture and an oxygen-containing gas at a converter burner outlet at a controlled flame temperature of 1100-2300DEG C for the conversion of hydrocarbons in the coke-oven gas and carbon dioxide or water vapor to generate a synthetic gas containing H2 and CO; and allowing the synthetic gas containing H2 and CO to enter a shaft furnace and reduce iron oxide in order to produce reduced iron, and cooling, washing, decarburizing, desulphurizing and purifying a reduced tail gas discharged from a shaft furnace to obtain a purified tail gas. The invention also provides a system for producing the gas-based directly reduced iron by utilizing the non-catalytic conversion of the coke-oven gas.

Description

technical field [0001] The invention relates to a method and system for producing gas-based direct reduced iron by non-catalytic conversion of coke oven gas, belonging to the technical field of direct reduced iron production. Background technique [0002] Direct reduced iron (DRI), also known as sponge iron, is a kind of metallic iron obtained without blast furnace smelting. The process of producing DRI is called non-blast furnace ironmaking process. The production process of DRI is divided into two types: coal-based and gas-based. At present, the gas-based method accounts for 90% of the output of DRI. The typical processes are tank method (HYL method) and shaft furnace method (Midrex method). The shaft furnace method uses a vertical moving bed reduction reactor, which is mainly divided into two parts: Reduction zone, where reducing gas circulates at high temperature, hydrogen and carbon monoxide above 800°C reduce iron oxide to generate DRI, hydrogen and carbon monoxide ge...

AI Technical Summary

Problems solved by technology

[0006] Chinese patent application CN102605132A discloses a method of using coke oven gas to produce direct reduced iron. In this method, the coke oven gas does not have fine desulfurization and a dedicated catalytic conversion process. The coke oven gas enters the reduction furnace after heating, and the reduced iron contains sulfur. The amount of methane in coke oven gas is high, and the utilization rate of methane in coke oven gas is low due to unsafe conversion

[0007] Chinese patent application CN101392192B discloses a coke oven gas carbon dioxide conversion and gas-based shaft furnace direct reduction iron production method. In this application, after the coke oven gas is deeply purified and desulfurized, oxygen, carbon dioxide and water vapor are added as gas conversion agents. Too much water vapor is added to the gas, after the conversion, it needs to be cooled to 40°C for dehydration treatment, and then the temperature is raised into the base shaft furnace. This process leads to high energy consumption due to the cooling and heating process of high-temperature syngas

Images