JPS62156217A - Controller for gas quantity for fluidized bed prereduction furnace - Google Patents

Abstract

PURPOSE:To stabilize operation while controlling furnace top gas quantity for prereduction furnace into a fixed width, by supplying furnace top gas of a melting reduction furnace to a fluidized bed prereduction furnace and introducing it to bypass arrangement to control its flow rate. CONSTITUTION:Pressure of blast air 1 is raised by a blast fan 2 and the air is heated to a prescribed temp. by a preliminary apparatus 3, then introduced into the melting reduction furnace 6 through a blast tuyere 5. Carbon material in furnace is burnt, reducing gas composed mainly of CO is generated, prereduced ore supplied from the prereduction furnace 10 through a piping 13 is finishedly reduced and melted to generate heat. The reducing gas is divided to two routes at furnace top, one is supplied into the fluidized bed prereduction furnace 10 through a piping 8, a dispersing plate 11, and the other flows together with exhaust gas of the furnace 10 through a bypass 9, a cooler 14 and a damper 15 and exhausted through a venturi scrubber 17. In this time, quantity of reducing gas to the furnace 10 is controlled by adjusting flow rate of reducing gas by the damper 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) A so-called smelting reduction furnace for smelting and reducing powdery ore is used to pre-inject the powdery ore to be subjected to smelting and reduction into a fluidized bed using top gas of the smelting and reducing furnace. It is equipped with auxiliary equipment that performs preliminary reduction and supplies the ore powder that has undergone preliminary reduction to the blast surface of the smelting reduction furnace. Therefore, we are conducting research and development on how to properly achieve the pre-reduction reaction in the fluidized bed by controlling the amount of gas required for the fluidized bed pre-reduction with respect to the amount of top gas generated accompanying the necessary reactions in the smelting reduction furnace. The results are described below.

(Prior art) A powder ore smelting reduction facility in which the above-mentioned fluidized bed pre-reduction furnace is attached to a smelting reduction furnace is disclosed in, for example, JP-A-57-1.
It is disclosed in Japanese Patent No. 98205.

In this case, the top gas of the smelting reduction furnace is used for preliminary reduction of the powdered ore in the fluidized bed, but in order to activate the fluidized bed smoothly, the amount of top gas introduced into the fluidized bed must be adjusted to a certain level. It is necessary to keep the temperature within this range, otherwise there will be disadvantages such as gas blow-through and insufficient fluidization.

(Problems to be Solved by the Invention) The amount of gas airflow at the top of the smelting reduction furnace, which requires four people to use in the fluidized bed pre-reduction furnace, the type of carbon material to be supplied and filled into the smelting reduction furnace, and the number of people in the fluidized bed pre-reduction furnace. It is an object of the present invention to provide a system that can be easily adjusted according to the type of powdered ore to be sequentially supplied, the temperature of the furnace top gas, the furnace conditions, etc.

(Means for Solving the Problems) This invention connects a carbon fiber optic layer type smelting reduction furnace in series to a fluidized bed pre-reduction furnace through the top gas introduction piping, and the fluidized bed pre-reduction furnace The pre-reduced ore powder that has passed through the furnace is supplied to the blower of the smelting reduction furnace to perform smelting reduction.
In the smelting and reduction equipment for powdered ore, an exhaust pipe for the above-mentioned furnace top gas that bypasses the fluidized bed pre-reduction furnace is provided in the smelter and reduction furnace, and a throttling means is provided in this exhaust pipe to remove the exhaust pipe necessary for the fluidized bed pre-reduction furnace. This is a gas amount adjustment device for a fluidized bed pre-reduction furnace, characterized in that the gas flow rate is controlled independently of the amount of gas required for the smelting reduction furnace.

Now, FIG. 1 illustrates a specific example of a gas amount adjusting device for a fluidized bed pre-reducing furnace for smelting and reducing powdery ore according to the present invention. Preheating equipment, 4 is an annular pipe, 5 is a blower panel, 6 is a melting reduction furnace, 7
is coke or other carbonaceous material to be supplied to the melting reduction furnace 6, 8 is the furnace top gas piping to the fluidized bed pre-reduction furnace, 9 is also the furnace top gas bypass piping, 10 is the fluidized bed pre-reduction furnace, 11 is a gas distribution plate placed in the pre-reduction furnace lO;
Reference numeral 2 denotes powdered ore to be supplied to the fluidized bed pre-reduction furnace 10, 13 is a pipe for transporting the pre-reduced ore powder from the fluidized bed pre-reduction furnace 10 to the blowing tuyere 4 of the melting reduction furnace 6;
4 is a gas cooler, 15 is a damper, 16 is a Zyclone for primary dust removal of exhaust gas, 17 is a pentier scrubber that serves both gas cooling and dust removal, and 18 is a final exhaust gas. This final exhaust gas is used for fuel and other purposes.

(Function) The blown air 1 is first boosted in pressure by the blown fan 2, and is then sent to the preheating equipment 3.
After raising the temperature to a predetermined temperature, it passes through the blast tuyere 5 and enters the melting reduction furnace 6.

As a result, the carbonaceous material in the furnace burns and generates reducing gas mainly composed of CO, and the pipe 13 is connected to the pre-reduction furnace 10.
Heat is generated to finish reduce and melt the pre-reduced ore supplied through the process.

This reducing gas is split into two routes at the top of the furnace.

One is supplied into the fluidized bed pre-reduction furnace lO through the gas pipe 8, and the other is supplied through the bypass pipe 9 and cooled by the gas cooler 14, and after adjusting the flow rate with the damper 15, the fluidized bed It joins with the exhaust gas from the bed pre-reduction furnace 10, passes through a venturi scrubber 17, and is finally discharged.

The procedure for adjusting the flow rate on the fluidized bed side using this bypass piping 9 will be described below.

First, if the amount of gas required for fluidized bed activation is close to the amount of gas required by the smelting reduction furnace 6, tighten the damper to increase the pressure drop on the bypass side and reduce the flow rate of the bypass. Com. In this way, almost all of the gas from the smelting reduction furnace is supplied to the preliminary reduction furnace.

Conversely, if the amount of gas required by the fluidized bed is smaller than the amount of gas generated from the smelting reduction furnace, open the damper 15 of the bypass piping 9 to increase the flow rate on the bypass side and reduce the amount of gas on the fluidized bed side. It can be lowered.

In this way, it is possible to keep the amount of gas in the fluidized bed within a certain range. In order to detect that the amount of gas on the fluidized bed side is constant, it is desirable to have a flow meter, but since the gas is hot and dirty, it is difficult to use a conventional flow meter. Therefore, in order to detect a constant gas amount, it is desirable to measure the differential pressure in the fluidized bed and adjust the opening degree of the damper 15 of the bypass pipe 9 so that this differential pressure becomes approximately constant. Incidentally, the amount of gas flowing into the melting reduction furnace 6 can be easily measured by a conventional method if it is carried out before air preheating.

Bypass piping 9 can be used for - In order to easily control the gas flow rate, in addition to lowering the temperature with a cooling device 14 as shown in the figure and adjusting it with a normal damper, it can also be used with a damper equipped with a cooling means such as water cooling. The cooling device may be omitted.

By the way, Fig. 2 shows a conventional smelting reduction furnace equipment that has a coke-filled bed type smelting reduction furnace and a fluidized bed pre-reduction furnace. If the air volume is too large, gas will blow through, leading to a decrease in yield, etc.
On the other hand, if it is too small, it will not become fluid.

The amount of air that should be supplied to the smelting reduction furnace depends on the type of carbonaceous material, the type of powdered ore, the required top gas temperature, furnace conditions, etc. In other words, there may be an imbalance in the amount of gas required between the smelting reduction furnace and the flowing VJ layer, which are connected in series, and in this case, there is a problem that the furnace capacity decreases and sometimes it becomes impossible to operate. be. As described above, in this invention, the fluidized bed pre-reduction furnace and the smelting reduction furnace connected in series can each be operated with the optimum gas amount.

In other words, the amount of air blown from the smelting reduction furnace to the smelting reduction furnace is maintained while maintaining the amount of air that achieves the tuyere tip temperature and furnace top temperature that the reduction furnace should have (this varies depending on the type of carbon material, furnace conditions, etc.). High that occurs? ! jL reducing furnace top gas (900℃~1
This makes it possible to maintain the amount of gas introduced into the fluidized bed pre-reduction furnace using a temperature of 200° C.) within a certain range.

(Effect of the invention) The gas amount is independently adjusted so that the fluidized bed pre-Oju reduction furnace and the smelting reduction furnace each have the optimum gas amount required.
- Since it can be used as a fuel, operations are stable and it is possible to adapt to changes in the type of carbonaceous material, brand of powdered ore, etc. In other words, it is easy to maintain and improve the productivity of the furnace and to change to cheaper raw materials.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a conventional example. 5...Blow tuyere 6...Melting reduction furnace 8...
・Introduction piping 9...Bypass piping 15...
Squeezing means

Claims (1)

[Claims] 1. A carbonaceous packed bed type smelting reduction furnace is connected in series to the fluidized bed pre-reduction furnace through the top gas introduction piping, and the pre-reduction that passes through the fluidized bed pre-reduction furnace is In a powdered ore smelting reduction facility that supplies finished ore powder to the blast tuyere of a smelting reduction furnace and smelting reduction, the furnace top gas exhaust piping that bypasses the fluidized bed pre-reduction furnace is connected to the smelting reduction furnace. A fluidized bed pre-reduction reactor, characterized in that the discharge pipe is provided with a throttle means to control the gas flow rate required in the fluidized bed pre-reduction furnace independently of the amount of gas required in the smelting reduction furnace. Gas amount adjustment device.