a use of ch 4 A direct reduction process for the production of sponge iron by non-catalytic oxygen-enriched conversion

Abstract

The invention relates to a direct reduction process for producing sponge iron by using CH4 non-catalytic oxygen-enriched transformation. A process route comprises the following steps: preheating a CH4-enriched raw gas and oxygen-enriched air which are subjected to purification and pressure regulation, then introducing the CH4-enriched raw gas and the oxygen-enriched air into a non-catalytic oxygen-enriched transformation furnace for a combustion reaction in the non-catalytic oxygen-enriched transformation furnace, and raising the temperature to transform CH4 therein into CO and H2 to form a high-temperature transformation gas; in the meantime, cooling, dedusting and pressurizing a top gas of a shaft furnace, then introducing the top gas into a hydrogen purification device to prepare purified hydrogen, preheating the purified hydrogen, and then introducing the preheated purified hydrogen into the lower part of the catalyst oxygen-enriched transformation furnace to be mixed with the high-temperature transformation gas generated through the combustion reaction to form a reduced coal gas; and introducing the reduced coal gas into the shaft furnace to reduce iron ores into the sponge iron. The direction reduction process disclosed by the invention not only has the advantages of short process flow, availability for energy saving and emission reduction, long service life of a nozzle and low investment cost, and can be used to prevent the sponge iron from caking and avoid carbon formation.

Description

technical field [0001] The present invention relates to a method utilizing CH 4 The invention relates to a direct reduction process for producing sponge iron by non-catalytic oxygen-enriched transformation, which belongs to the technical field of iron or steel smelting. 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 redu...

AI Technical Summary

Problems solved by technology

[0005] 1) Use the coke oven gas and the purified and decarburized shaft furnace top gas together, humidify and then heat to about 1000°C and enter the shaft furnace to reduce iron ore. The key to this technical route is to use high temperature and the catalytic effect of sponge iron. make part of ch 4 A reforming reaction occurs to generate CO+H 2 Supplement reducing gas, but this process requires decarburization and oxygen spraying to raise temperature. At the same time, at a temperature of about 1000 ° C, if the reducing gas atmosphere is not well controlled, there will be defects that sponge iron is easy to stick;

[0006] 2) Use oxygen, coke oven gas, carbon dioxide, and water vapor to convert in the reformer, then mix with top gas, heat up to 800°C after desulfurization and decarburization, and enter the shaft furnace to reduce iron ore. At the same time, H 2 / CO>1.5; the process route of this technical route is complicated, and the heating furnace has strict restrictions on the gas composition to avoid carbon precipitation. ;

The raw material gas of this technical route reacts with pure oxygen, the reaction temperature is high, and the service life of the burner is short. In order to prolong the service life of the burner, steam needs to be introduced, which will lead to an increase in the oxidation degree of the reducing gas, which is not conducive to the reduction of ore.

[0009] To sum up, the current domestic technical route for methane-rich gas-based shaft furnace direct reduction processes such as natural gas and coke oven gas has long process flow, complex conversion process, insufficient conversion, easy sticking of shaft furnace, and the use of conversion burners. Technical defects such as short service life and high degree of conversion gas oxidation

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