Gas-electric hybrid type gas-based shaft furnace reduction system and method

Abstract

The invention relates to a reduction system and method of a gas-electric hybrid gas-based shaft furnace, which includes a feed bin, a preheating bin, a gas-electric hybrid gas-based shaft furnace and a melting furnace. The feed bin passes through the preheating bin and The gas-electric hybrid gas-based shaft furnace is connected, and the gas-electric hybrid gas-based shaft furnace is connected to the melting furnace. The present invention adopts gas and electric dual heat sources, and the temperature in the reduction section is high, the reaction speed is fast, and the reaction time is short. The metallization rate is high, and the reduced direct-reduced iron ore powder enters the electric melting furnace directly for melting in the hot state, which is more energy-saving; there is no need for a shaft furnace cooling section, which saves the volume of the equipment.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a gas-electric hybrid gas-based shaft furnace reduction system and method. Background technique [0002] The process of producing direct reduced iron is called the direct reduction method, which belongs to the non-blast furnace ironmaking process and is divided into two categories: gas-based method and coal-based method. Gas-based methods mainly include Midrex, HYL, PERED, and fluidized bed, and coal-based methods are mainly rotary kiln and rotary hearth furnace methods. About 80% of direct reduced iron is produced by gas-based methods, mainly MIDREX method and HYL method. [0003] Gas-based direct reduction technology has been widely used in natural gas-rich areas. In recent years, with the development and utilization of coal-to-gas as reducing agent technology, gas-based shaft furnace direct reduction technology has attracted widespread attention in my country. ...

AI Technical Summary

Problems solved by technology

In order to ensure the quality of direct reduced iron products, the direct reduction process has extremely strict requirements on iron-containing raw materials, especially iron ore pellets that are directly fed into the furnace. properties, and the ore is generally set in a stacked state in the shaft furnace, because the diffusion of gas in the stacked ore is slow, it takes about 6 hours for full reduction, and the reduction and cooling are all carried out in the furnace body, further prolonging the process Time will also cause inconvenience in controlling the temperature and gas composition in the furnace

The existing gas-based shaft furnace only relies on the heat brought in by the reducing gas as the heat source. The actual reduction temperature is around 800-920°C, and it is difficult to further increase the reduction temperature, which directly limits the reduction rate of the pellets, which is the main reason for the long reduction time. one of the limiting factors

[0004] The commonly used fluidized bed process is the Fior flow state method, which uses mineral materials in the range of 0.25-4mm. The mineral materials are in a suspended state on the fluidized bed, which increases the contact area with the reducing gas. Coarse, the reduction time can only be reduced to a certain extent. At the same time, the fine-grained ore powder is easy to escape and the gas utilization rate is low. To solve these problems, generally multiple fluidized beds are used in series to increase the contact time between the ore and the reducing gas. to improve gas utilization, which complicates the process

[0005] In the various process systems mentioned above, in order to make the reducing gas meet the use requirements, multiple gas heating and cooling devices need to be installed, which not only increases the equipment investment, but also makes the process system complicated

[0006] It can be seen that the current direct reduction ironmaking technology generally has problems such as low reduction efficiency and complicated process equipment. Therefore, there is an urgent need for a method and system that has high reduction efficiency, simple process, and is conducive to improving the metallization rate.

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