Method for preparing simple substance iron by virtue of pyrolytic gas

Abstract

The invention discloses a method for preparing simple substance iron by virtue of a pyrolytic gas. The method comprises the steps of (1) mixing the pyrolytic gas which is obtained by performing pyrolysis treatment on middle- and low-rank coal, junked tire, biomass or garbage, with a transforming agent; (2) carrying out a transformation reaction of the mixture obtained in the step (1) in a transformation furnace so as to obtain a reducing gas; (3) reducing the iron ore in a shaft furnace by virtue of the reducing gas obtained in the step (2) so as to obtain the simple substance iron and a reaction tail gas;(4) performing waste heat recovery treatment on the reaction tail gas by using a waste heat boiler so as to obtain water vapor and the cooled reaction tail gas; and (5) returning one part of the cooled reaction tail gas and the water vapor as the transforming agent to be mixed with the pyrolytic gas in the step (1), and returning the other part of the cooled reaction tail gas to the step (2) as a fuel of the transformation furnace. Due to the method, the simple substance iron preparation cost can be remarkably reduced.

Description

technical field [0001] The invention belongs to the field of metallurgy, and in particular, the invention relates to a method for preparing simple iron from pyrolysis gas. Background technique [0002] Direct reduced iron (DRI) is an elemental product containing iron obtained by direct reduction of iron ore at a temperature lower than the melting temperature. Direct reduced iron has a stable chemical composition and low impurity content. It is one of the substitutes for scrap steel. It is an indispensable impurity diluent for electric furnace smelting pure steel and high-quality steel. It is a high-quality coolant for converter steelmaking. missing raw materials. Direct reduced iron has been listed as one of the main directions for the development of my country's iron and steel industry. [0003] At present, the methods of industrial production of direct reduced iron are mainly divided into two categories: gas-based method and coal-based method. About 76% of the world's d...

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Problems solved by technology

However, there is a shortage of natural gas resources in my country, so the use of natural gas as energy is not conducive to the promotion and application of gas-based shaft furnace technology in China

Coke oven gas is produced from coking coal resources through the coking process. Coking coal resources are increasingly in short supply. The coking process consumes high energy and causes heavy pollution. Therefore, using coke oven gas as an energy source is only suitable for promotion in some areas

Coal gasification gas production technology is becoming more and more mature, but the investment is high, so the benefit of using coal as energy to produce direct reduced iron is not good, which is not conducive to popularization

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