Sponge iron production technology by coal gasification

Abstract

The invention belongs to the metallurgy technical field and discloses a sponge iron production technology by coal gasification. The invention is characterized in that: coal and oxygen, water or steam react in a high temperature high pressure entrained flow gasifier to generate reducing coal gas rich in CO+H2, the reducing coal gas is subject to dust removal, desulfuration and pressure and heat transformation by a gasifier discharge coal gas process system and then mixed with decarburization gas rich in CO+H2 after shaft furnace top gas passes through a return coal gas process system and a carbon dioxide separation system, and then the mixed gas is heated to the temperature range required by the shaft furnace and then fed into the shaft furnace to reduce iron ore, so as to produce sponge iron. The invention reduces high temperature high pressure entrained flow gasifier cost; the shaft furnace top gas circulating reflux is fully utilized to reduce coal use consumed in sponge iron production, and cost is saved; and CO2 is collected and recycled.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, relates to the engineering field of producing sponge iron by using reduced gas produced by coal gasification in iron and steel plants, and discloses a process for producing sponge iron by coal gasification. technical background [0002] Under the general environment of energy conservation and emission reduction at home and abroad, the defects of the long-process steelmaking process of using coke, sinter or pellets to produce molten iron in the blast furnace and then sending it to the converter for steelmaking are very obvious, such as the shortage of coking coal resources, coking and Land occupation and cost of sintering, massive discharge of three wastes, etc. The short-process process of using sponge iron and scrap steel to make steel can save investment in coking and sintering, reduce waste discharge, and have obvious economic and environmental benefits. The acquisition of sponge iron in s...

AI Technical Summary

Problems solved by technology

This process has high requirements on reducing gas composition (CO+H 2 >90%), only for the expensive high-pressure pulverized coal gasification technology, the investment is relatively high; secondly, the process proposes that the top gas of the shaft furnace is washed and reheated before entering the shaft furnace, which will greatly reduce the reduction degree of the reduced gas , because the CO+H of the shaft furnace top gas 2 Only about 60%; In addition, the tube furnace and partial oxidation two-step gas heating method used in this process will lose ~5% of the reducing gas. In this case, mix CO+H 2 ~60% of the shaft furnace top gas enters the shaft furnace, whether the degree of gas reduction at this time can be guaranteed is debatable

[0004] To sum up, in addition to the COREX patent system of Siemens VAI (SVAI), the current coal gasification production sponge iron process at home and abroad has some defects, and further improvement is needed if it is to be industrialized

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