Direct reduction process for producing spongy iron from CH4-rich coal gas

Abstract

The invention discloses a direct reduction process for producing spongy iron from CH4-rich coal gas, which comprises the following steps: a, inputting CH4-rich coal gas subjected to pressure regulation and gas-based shaft furnace top gas sequentially subjected to cooling, dust removal and pressurization treatment into an outer converter, supplementing steam taken as modification reaction oxidizer of CH4 into the outer converter, and enabling CH4, H2O and CO2 in the outer converter to be subjected to modification reaction under the effect of a catalyst to generate high-temperature reducing coal gas mainly containing CO and H2; and b, inputting the high-temperature reducing coal gas generated in the outer converter into a gas-based shaft furnace to directly reduce iron ores to generate spongy iron. According to the invention, CO2 in the top gas is fully utilized to generate CO so as to provide reducing gas, thereby reducing the discharge of CO2, omitting the coal gas decarburization procedure and ensuring that the process is simple; and CH4 in the raw gas is subjected to thorough reaction, and the temperature of the high-temperature reducing coal gas is controlled at 850 DEG C, thereby realizing that the utilization efficiency of the raw gas is high, and avoiding the problems of blockage and shaft furnace cementation caused by a great amount of carbon precipitate of CH4 at high temperature.

Description

technical field [0001] The invention relates to the field of metallurgy, in particular to a process for producing sponge iron through direct reduction in the iron and steel industry. Background technique [0002] The iron and steel industry is the basic industry of the national economy, and it is also a key industry in my country's energy resource consumption and pollution discharge. In order to speed up structural adjustment and industrial upgrading of the iron and steel industry, change the development mode of the iron and steel industry, and promote economical, clean and sustainable development, the state proposed in the "Steel Industry Adjustment and Revitalization Plan" to "strengthen non-blast furnace smelting-steelmaking, refining-direct Rolling new process clean process technology research and development and testing" as a key task to promote energy conservation and emission reduction in the whole industry, fully promote clean production. [0003] As a typical non-b...

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Problems solved by technology

[0006] In view of this, the purpose of the present invention is to provide a 4 A direct reduction process for producing sponge iron from coal gas to solve the shortcomings of the existing direct reduction process; this process adopts the form of catalytic conversion in an external reformer to convert rich CH 4 The raw material gas and the top gas after cooling and dedusting are carried out in the external reformer for methane conversion and reforming reaction, making full use of the CO in the top gas 2 Generate CO to provide reducing gas and reduce CO 2 discharge; at the same time, the steam generated by the top gas heat exchanger is added as an oxidant, and the added amount is determined by the rich CH 4 CH in feed gas 4 In addition, control the outlet temperature of the external reformer at about 850°C to reduce fuel gas consumption and prevent sponge iron from sticking

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