Device and method for top gas enrichment utilization of blast furnace

Abstract

The invention relates to a device and method for top gas enrichment utilization of a blast furnace, in particular to a device and method for using top gas in a blast furnace production process, belonging to the field of smelting pig iron with the blast furnace. The device is characterized in that: a tee joint is arranged on a pipeline between a gas purifying and de-dusting system and an excess pressure power generation device; a gas pressurization device, a gasification furnace and a gas back-eject hole which is formed on the blast furnace are connected through the pipeline and a valve to form one way of the tee joint; the gasification furnace is provided with an oxygen supply pipeline and a coal blending device; the enriched gas, after being pressurized, enters the gasification furnace and is subjected to gasification reaction with oxygen and powder coal in the pressurized gasification furnace; a reaction product is ejected into the blast furnace for smelting iron through the back-eject hole which is formed on the blast furnace; the excess pressure power generation device is respectively connected with a hot blast heater, a power plant boiler pipeline and a valve through a gas distributor to form another way of the tee joint; and the generated hot air is fed into the blast furnace through a nozzle. The device has the advantages of novel conception, simple process flow, easiness in implementation, safety and reliability in operation and capabilities of increasing the calorific value of gas, ejecting back to smelt iron, increasing the indirect reduction rate, reducing the coal ratio, reducing blast furnace slag and CO2 emission, regulating and controlling the width of a cohesive zone of the blast furnace, ensuring long-term smooth running of the blast furnace, avoiding diffusion of the top gas, saving energy and contributing to environment friendliness.

Description

technical field [0001] The invention belongs to blast furnace pig iron smelting, in particular to a device and method for using top gas in blast furnace production. Background technique [0002] Blast furnace smelting is still the most important method of ironmaking today. Blast furnace ironmaking consumes a lot of energy, and the ironmaking coke ratio is 300-500kg / tFe. During the ironmaking process, a large amount of high-temperature, high-pressure, and dust-containing furnace top gas (hereinafter referred to as gas) is produced at the same time, with a temperature of 180-250°C, a pressure of 150-250kpa, and a dust content of 15-20g / Nm 3 . Coal gas contains about 25% CO and 25% CO 2 . In order to improve energy utilization and reduce environmental pollution, ironmaking engineers have done a lot of useful work and achieved certain results. At present, the blast furnace top gas utilization device used is to remove the gas by gravity and cyclone, and connect it to the rel...

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Problems solved by technology

[0003] The disadvantages are: the calorific value of gas is low, and it must be used with other fuels or oxygen-enriched combustion before it can be used for power generation and baking metallurgical furnaces. The cost of recycling is high and the income is low; the impact of blast furnace production fluctuations on gas composition and flow large, which affects the operation of the gas utilization device; the gas is often discharged directly through the release valve, and the gas releases a lot, the utilization rate is low, and it also pollutes the environment

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