JPS6014803B2 - Quality control method of reduced iron in floating reduction process - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method for maintaining the quality of reduced iron, that is, the metallization rate or reduction rate, etc., in a constant state in a floating reduction process.

In recent years, a heated atmosphere is formed in the tower, carbon particles or powder are introduced into this atmosphere to form a carbon floating layer, and an iron oxide raw material is passed through the floating layer to form a part of the floating layer. While reducing the iron oxide raw material in a reducing gas atmosphere of carbon oxide or hydrogen, the carbon particles and carbon particles generated by this reduction reaction are reacted to create a reducing atmosphere of carbon monoxide and hydrogen. A floating reduction process that can generate hydrogen and increase the reduction efficiency as much as possible is attracting attention.

However, in the floating reduction process, in order to always produce reduced iron of a constant quality, it is necessary to: ■ ensure that sufficient reducing gas is generated within the floating layer, and ■ ensure that iron oxide is sufficiently reduced within the suspended layer. It is necessary to satisfy one of the following conditions: ■ Depletion due to coke and gasification of the fine coal that forms the floating layer, @ Changes in composition due to differences in the type of fine coal, ■ Due to differences in raw material ores. Due to changes in operating conditions such as changes in the difficulty of reduction of the raw material ore, the above two conditions may not be satisfied and the metallization rate or reduction rate of reduced iron may not be able to be maintained constant. be.

The present invention was made for the purpose of keeping the metallization rate or reduction rate of the produced reduced iron constant even if the operating conditions change. In the floating reduction process, in which iron ore is introduced into a floating layer of carbon formed in one or more of the coal villages, carbonaceous material and iron ore can be supplied individually, and as a product. It is characterized by detecting the reduced iron characteristics such as the amount of oxygen, reduction rate, metallization rate, or specific gravity of the extracted reduced iron, and controlling the supply ratio of iron ore and carbonaceous material so that the reduced iron characteristics are constant. That is.

Embodiments of the present invention will be described below with reference to the drawings. Reaction tower 1 in which a suspended layer of pulverized coal, etc. is formed inside.
A process gas supply V supply pipe 4 is attached to the lower side of the reaction tower 1 for feeding the process gas, which has been pressurized by the blower 2 and heated by the heater 3, into the reaction tower 1. A separator 7 is provided which separates fluid particles such as char or coke from reduced iron, and allows fluid particles 5 and reduced iron 6 to be taken out separately.

Further, an analyzer 9 for oxygen in the reduced iron 6 is attached to the extraction route 8 for the reduced iron 6. A process exhaust gas discharge pipe 10 is provided at the top of the reaction tower 1, and a venturi scrubber/cooler 11 is connected to the midway part of the process exhaust gas discharge pipe 10 for dust removal and thin haze heat utilization. .

At the top of the reaction tower 1, there is a chute 1 that splits into two from the middle.
A screw feeder 13 is attached to one of the bifurcated portions of the chute 12, and a screw feeder 14 is attached to the other.

Furthermore, an iron ore hopper 1 is placed on the screw feeder 13.
A fine coal hopper 16 is disposed on the screw feeder 14, respectively. Screw feeder 13
, 14 drive motors 17, 18 are connected to a ratio setting device 19.
, 20, and the ratio setters 19, 20 are connected to
Both are interlocked with analyzer 9.

During operation, it is determined in advance by experiment what percentage of oxygen is in the reduced iron 6 taken out from the separator 7, and what percentage of the weight of the iron ore and the weight of the powdered coal should be. This is determined in advance and set in the ratio setters 19 and 20, respectively.

The heated and elevated process gas is supplied into the reaction tower 1 from the process gas supply pipe 4, and pulverized coal is supplied from the screw feeder 14, and iron ore is supplied from the screw feeder 13 into the reaction tower 1, respectively. As a result, a suspended layer of powdered coal is formed in the reaction tower 1, which is reduced by the iron ore process gas to become reduced iron, which is then transferred from the reaction tower 1 to the separator 7.
The reduced iron and the fluidized particles are separated here, and the reduced iron 6 is taken out to the outside through the extraction path 8, and the fluidized particles 5
is sent to reaction column 1 and reused. The process gas is oxidized by reducing the iron ore, but as it rises through the floating layer of pulverized coal, it is reduced again and becomes a reducing gas, which is discharged into the process gas discharge pipe 10 as process exhaust gas, which serves as a venturi scrubber. The dust is removed and the residual heat is recovered in the cooler 11, and then the pressure is increased, the heat is heated, and the process gas is supplied to the process gas supply pipe 4 for reaction.
are combined in circulation.

A portion of the reduced iron passing through the extraction path 8 is sampled by an analyzer 9 and chemically analyzed to detect the amount of oxygen in the reduced iron.

When the amount of oxygen analyzed is greater than a predetermined value, the degree of reduction of reduced iron is insufficient.

Therefore, in this case, the screw feeder 14 receives signals from the ratio setters 20 and 19 to reduce the value of 4.0, that is, to increase the amount of powdered coal or decrease the amount of iron ore. , 13 is changed, and the amount of oxygen in the reduced iron is controlled to be constant. Also, when the amount of oxygen analyzed by the analyzer 9 is less than the predetermined value, the reduction of reduced iron is sufficient, so in this case, it is necessary to increase the amount of iron ore or the amount of powdered coal to increase the value. The supply amount of the screw feeders 13 and 14 is adjusted so as to decrease the amount. In the embodiments of the present invention, the case where oxygen in reduced iron is analyzed has been explained, but any method can be used to analyze reduced iron characteristics such as reduction rate, metallization rate, specific gravity, etc. It is possible to perform control to keep the ratio constant, and if a computer is installed between the analyzer and the ratio setting device, highly accurate control can be performed, and other aspects that do not depart from the gist of the present invention. Of course, various changes may be made.

Since the method for controlling the quality of reduced iron in a floating reduction process of the present invention has the above-described configuration, it can produce the effect that the metallization rate or reduction rate of reduced iron can be controlled to a constant state.

[Brief explanation of drawings]

The drawings are explanatory diagrams of the present invention. In the figure, 1 is a reaction tower, 4 is a process gas supply pipe, 6 is reduced iron, 7 is a separator, 8 is an extraction route, 9 is an analyzer, 13,1
4 shows a screw feeder, 19.2 shows a ratio setting device.

Claims (1)

[Claims] 1. In a floating reduction process in which iron ore is introduced into a carbon floating layer formed by any one or some of carbon materials such as pulverized coal, char, and coke,
Carbon material and iron ore can be supplied individually, and reduced iron characteristics such as oxygen content, reduction rate, metallization rate, or specific gravity of reduced iron extracted as a product are detected, and the reduced iron characteristics are kept constant. A method for controlling the quality of reduced iron, characterized by controlling the supply ratio of iron ore and carbonaceous material.