JPS62228406A - Operating method for melt reduction furnace - Google Patents

Abstract

PURPOSE:To effectively utilize a melt reduction furnace as a gas generating furnace by adding liquid fuel such as heavy oil and tar in suitable time to the melt reduction furnace into which preliminarily reduced iron ore is blown together with a carbonaceous material as a reducing agent as well as slag forming agent and oxygen to produce a molten iron. CONSTITUTION:The iron ore is preliminarily reduced in the solid phase. The carbonaceous material as the reducing agent in common use as fuel as well as the gaseous oxygen for heating and melting and the flag forming agent such as quicklime are blown into the molten iron in the melt reaction furnace so that the molten iron is produced by melt reduction of the preliminarily reduced iron ore. A combustible gas contg. CO is generated from the melt reduction furnace in this case and therefore, the gas is supplied as the fuel gas in the time zone such as nighttime when the demand of the gas is low. Liquid fuel such as tar or heavy oil is blown into the melt reduction furnace to increase the amt. of the combustible gas to be generated in the time zone such as daytime when the demand of the gas is high. The melt reduction furnace is thus effectively utilized as the gas generating furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to gas production control in a smelting reduction method for obtaining pig iron by smelting and reducing iron ore and the like.

(Conventional technology) In recent years, instead of the blast furnace method, which uses lump coke and sintered ore to produce pig iron, raw ore and powdered ore are blown into an iron bath furnace together with carbonaceous materials such as powdered coal to directly produce molten iron. A reduction method has been developed (Japanese Unexamined Patent Publication No. 145307/1983), which makes it possible to obtain an iron bath and at the same time obtain gas from the carbonaceous material. Not only has it not been used effectively, but there has been no technology for effectively balancing the use of gas generation and maintaining the iron bath.

(Problems to be solved by the invention) Conventionally, in the steel industry, gas generation as well as iron production is a more important work than other processes, and in the smelting reduction method,
It is important to be able to generate gas under all conditions, so that gas generation can be performed easily, and gas generation and obtaining or maintaining molten iron can be performed smoothly as necessary. The purpose of this study is to provide a method for operating a smelting reduction furnace.

(Means for Solving the Problems) The present invention is applicable to the smelting reduction method in which iron ore, etc. is pre-reduced and blown into an iron bath together with carbonaceous materials, oxygen, slag-forming agents, etc. When the temperature is high, in addition to coal, liquid fuels such as heavy oil and tar are injected into the smelting reduction furnace to generate a large amount of gas.
By taking it out of the system, it can function as a gas generating furnace, and when the demand for gas is low, it can be used as an iron manufacturing furnace by balancing the amount of carbon material injected to the amount required for bath iron manufacturing. This is a distinctive method of operating a melting reduction furnace.

(Function) In the present invention, when a liquid fuel such as heavy oil or tar in addition to coal is blown into the smelting reduction furnace, the smelting reduction reaction of the smelting reduction furnace is reduced and a large amount of gas is generated. Since liquid fuel is used at this time, the nozzle and lance do not wear out, so it can be used as a gas generating furnace for a long period of time.

Furthermore, gas obtained from heavy oil and tar has a high caloric content due to its high H2 and NH1 content, so it is possible to provide a gas with high utility value, and also to prevent the generation of slag due to ash, which is generated when coal is used in a smelting reduction furnace. The furnace can be operated easily.

(Example) A description will be given below based on the steps of a general melting 11-element method. When carrying out a normal smelting reduction reaction in a smelting reduction furnace, smelting and reduction is carried out by blowing main raw material such as reduced iron, carbonaceous material, coal powder, slag forming agent, etc. into an iron bath or a slag bath. To give an example of the operation when a smelting reduction furnace is used as a gas generating furnace, after a certain amount of iron bath is generated in the smelting reduction furnace, liquid fuel such as carbonaceous material, heavy oil, tar, etc. When injected, the liquid fuel is heated by the iron bath and gas is generated.

(Effects of the Invention) According to the present invention, by injecting liquid fuel such as heavy oil or tar in addition to coal into the smelting reduction furnace, the smelting reduction reaction of the 78 smelting reduction furnace is reduced and gas generation is increased in large quantities. When the demand for gas is high, it can serve as a gas generating furnace by releasing the gas outside the system. Since liquid fuel is used at this time, the nozzle and lance are less likely to wear out, so it can be used as a gas generating furnace for a long period of time. Furthermore, if the injection of liquid fuel, coal, etc. is stopped, melting and reduction operations can be performed, resulting in good work efficiency. Furthermore, when liquid fuel such as heavy oil or tar is used, there is no need to turn the heavy oil or tar into powder like carbonaceous material in order to charge it into the melting reduction furnace through the nozzle or lance of the melting reduction furnace. Gas obtained from tar has a high calorific value and can provide gas with high utility value.
It is possible to prevent the generation of slag due to ash, which is generated when coal is used in a seven-head furnace, and it has an equivalent effect that makes it easy to change to normal smelting reduction operation.

Claims (1)

[Claims] Preliminary reduction of iron ore, etc., along with carbonaceous material, oxygen, slag forming agent, etc.
In the smelting reduction method where gas is injected into the iron bath, during the daytime and other times when the demand for gas is high, in addition to coal, liquid fuels such as heavy oil and tar are injected into the smelting reduction furnace to generate a large amount of gas, which is then discharged from the system. The smelting reduction furnace is characterized in that it functions as a gas generating furnace, and when the demand for gas is low, it can function as an iron manufacturing furnace by balancing the amount of carbon material injected with the amount necessary for manufacturing molten iron. How to operate a furnace.