JPS6014802B2 - 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 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 such as carbon oxide or hydrogen, a reducing atmosphere with a high concentration of carbon monoxide or hydrogen is created by reacting carbon particles or carbon particles with carbon dioxide or water vapor generated by this reduction reaction. The floating reduction process is attracting attention because of its ability to generate and increase reduction efficiency as much as possible. However, in the floating reduction process, in order to always produce reduced iron of constant quality,
■ Sufficient reducing gas is generated within the floating layer, ■
It is necessary to satisfy one condition that the iron oxide is sufficiently reduced in the floating layer, but ■ consumption due to coke formation and further gasification of the pulverized coal that generates the floating layer, The above two conditions cannot be satisfied due to changes in operating conditions such as changes in composition due to differences in powdered coal types, changes in reduction difficulty due to differences in raw material ores, etc.
There is a possibility that the quality of reduced iron cannot be maintained constant.

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 a floating reduction process in which iron ore is introduced into a floating layer of carbon formed by any one or some of the carbonaceous materials, the carbonaceous material and iron ore can be supplied separately, and the process exhaust gas is This system is characterized by analyzing the components in the exhaust gas and controlling the ratio of the amount of iron ore and the amount of carbonaceous materials based on the analyzed values so that the components in the exhaust gas remain constant.

Embodiments of the present invention will be described below with reference to the drawings.

A process gas whose pressure is increased by a blower 2 and heated by a heater 3 is fed into the reaction tower 1 at the lower side of the reaction tower 1 in which a suspended layer of pulverized coal or the like is formed inside. A supply pipe 4 is attached, and a separator 7 is installed at the bottom of the reaction tower, which separates fluidized particles such as char or coke from reduced iron, and allows fluidized particles 5 and reduced iron 6 to be taken out separately. It is provided.

A process exhaust gas discharge pipe 8 is provided in the upper part of the reaction tower 1, and a venturi scrubber/cooler 9 for dust removal and heat utilization and a venturi scrubber/cooler 9 for dust removal and heat utilization are installed in the middle of the process exhaust gas discharge pipe 8. A component analyzer 10 for analysis is attached.

At the top of the reaction tower 1, there is a chute 1 that splits into two from the middle.
A screw feeder 12 is attached to one of the bifurcated portions of the chute 11, and a screw feeder 13 is attached to the other.

Furthermore, an iron ore hopper 1 is placed on the screw feeder 12.
4, fine coal hoppers 15 are disposed on the screw feeders 13, respectively. Screw feeder 12
, 13 drive motors 16, 17 are ratio setters 18,
The ratio setters 18 and 19 are both interlocked with the component analyzer 101.

Before operation, determine in advance through experiments, etc., what percentage of carbon monoxide, hydrogen, or their total concentration is in the process exhaust gas, the ratio of the weight of iron ore to the weight of fine coal, and the ratio of the weight of iron ore to the weight of pulverized coal. is calculated in advance, and this is set in the ratio setter 18, 1.
Set each to 9. If pressurized and heated process gas is supplied into the reaction tower 1 from the process gas supply pipe 4, fine coal is supplied from the screw feeder 13, and iron ore is supplied from the screw feeder 12 into the reaction tower 1. A suspended layer of pulverized coal, etc. is formed inside the iron ore, and the iron ore is reduced by the process gas to become reduced iron, which enters the separator 7 from the reaction tower 1, where the reduced iron and fluidized particles are separated and reduced iron is produced. is taken out, but the fluidized particles are removed from the reaction column 1.
sent to and reused.

On the other hand, 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 exhaust gas exhaust pipe 8 as a process exhaust gas, and is passed through the venturi scrubber. Dust is removed and sensible heat is recovered in a cooler 9, and a portion of the process exhaust gas is sent to a component analyzer 101, while the majority is pressurized and heated again and reacts as a process gas through the process gas supply pipe 4. It is circulated and fed to the column 1. For example, when the gas component analyzed by the component analyzer 10 is carbon monoxide, when the amount of carbon monoxide in the process exhaust gas is more than a predetermined value, the degree of reduction of the process exhaust gas is too large.

Therefore, in this case, increase the value of the cloud,
In other words, increase the amount of iron ore or reduce the amount of pulverized coal.
In response to signals from the ratio setters 18 and 19, the combined amount of the screw feeders 12 and 13 is changed, and the degree of reduction of the process exhaust gas is adjusted. Also, when carbon monoxide is less than a predetermined value, the process exhaust gas has not been reduced sufficiently, so in this case, the amount of pulverized coal should be increased or the amount of iron ore should be decreased so that the carbon monoxide value becomes smaller. The supply amount of the screw feeders 12 and 13 is adjusted. When analyzing carbon dioxide in process exhaust gas, reduce the times when carbon dioxide is higher than a predetermined value,
Control may be performed to increase the number of times when carbon dioxide is lower than a predetermined value.

In the examples of the present invention, the case where the component to be analyzed in the gas is carbon monoxide or carbon dioxide has been explained, but it is also possible to analyze hydrogen or water vapor alone. It can be carried out using any combination of hydrogen and water vapor, and in order to perform highly accurate control, it is sufficient to install a computer between the component analyzer and the ratio setting device, within the scope of 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 figure is an explanatory diagram of an embodiment of the present invention. In the figure, 1 is a reaction tower, 4 is a process gas supply pipe, 6 is reduced iron, 8 is a process exhaust gas discharge pipe, 1 is a river component analyzer, 12
, 13 are screw feeders, and 18 and 19 are ratio setters.

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,
We made it possible to supply carbonaceous materials and iron ore separately, analyzed the components in the process exhaust gas, and based on the analysis values, adjusted the supply ratio of the amount of iron ore and the amount of carbonaceous materials so that the components in the exhaust gas remained constant. A method for controlling the quality of reduced iron.