Method and system of preparing spongy iron by using gas-based shaft furnace

Abstract

A disclosed method of preparing spongy iron by using a gas-based shaft furnace comprises: (1) adding an oxidation pellet into the gas-based shaft furnace which possesses a reducing segment and a cooling segment; (2) performing hydrogen extraction processing on a first reducing gas to obtain hydrogen and carbon monoxide rich gas; (3) mixing a second reducing gas and hydrogen and performing heating processing, so as to obtain a thermal-state reducing gas; (4) conveying the thermal-state reducing gas into the reducing segment, and reacting with the oxidation pellet for reduction, so as to obtain spongy iron and furnace top gas; (5) conveying carbon monoxide rich gas into the cooling segment, so as to perform heat exchange between the carbon monoxide rich gas and spongy iron in the cooling segment and perform carburization reaction and then enable the gas to move upwards and enter the reducing segment; (6) performing washing cooling processing, compression processing and desulphurization decarburization processing on the furnace top gas, so as to obtain unreacted reducing gas; (7) mixing a part of the unreacted reducing gas with the first reducing gas; and (8) mixing the other part of the unreacted reducing gas with the second reducing gas. The method is capable of effectively reducing energy consumption of a technology of using the gas-based shaft furnace for direct reduction.

Description

technical field [0001] The invention relates to the technical field of metallurgy, in particular, the invention relates to a method for preparing sponge iron in a gas-based shaft furnace. Background technique [0002] Sponge iron is a steelmaking raw material that replaces steel scrap and is superior to steel scrap. It can dilute the impurity elements in steel scrap, provide essential pure iron raw materials for electric furnace steelmaking, and provide high-quality billet castings for important products produced by high-end equipment manufacturing enterprises. An important raw material for the development of equipment manufacturing industry. [0003] At present, more than 75% of the sponge iron in the world is produced by the gas-based shaft furnace method, and the typical processes are MIDREX process, HYL III (Energiron) process and PERED process. There are two ways to discharge sponge iron, hot discharge to produce hot briquette (HBI) and hot sponge iron (HDRI), and cold...

AI Technical Summary

Problems solved by technology

There are four problems in this method: (1) Since the reducing gas enters the shaft furnace from the bottom of the reducing section, and the sensible heat of the sponge iron is not utilized, the reducing gas heating equipment has a large scale and high energy consumption

(2) The reducing gas enters the shaft furnace from the surrounding tube at the bottom of the reduction section, and it is difficult for the reducing gas to reach the center of the shaft furnace, and the distribution of the reducing gas flow is uneven

(4) Due to the H in the circulating cooling gas 2 / The value of carbon monoxide is relatively high, the content of carbon monoxide in the gas is relatively low, and the carburizing effect of sponge iron is not very ideal

Images