JPS6033887B2 - Pulverized coal supply device for flash furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for supplying pulverized coal to a concentrate burner as fuel in a flash furnace.

In the flash furnace, concentrate is supplied from a millet burner at the top of the shaft, and at the same time, heavy oil as a fuel and heated air or oxygen-enriched air for oxidizing the concentrate and for fueling the heavy oil are supplied.

In large flash furnaces, these supplies are carried out by a plurality of concentrate burners. The amount of heavy oil supplied as fuel is adjusted to the desired quality of the steel or nickel matte produced, as well as to the composition of the feeder to be supplied in order to control the temperature of the produced matte or slag at an appropriate temperature. Determined by It is necessary to quickly adjust the amount of heavy oil supplied in response to changes in various conditions during operation in order to stabilize furnace conditions and maintain high productivity. It is also important to prevent local damage to the refractories that make up the refractories. Recently, the use of pulverized coal as an alternative fuel has been considered due to the rising price of heavy oil, but its physical properties make it difficult to supply it evenly to multiple burners.

One method would be to mix fine coal with dry ore, store it in a hopper above the furnace, and supply it to the Inuaseite burner, but in this case, the amount of fine coal would be determined independently of the amount of processed concentrate. Changes cannot be made quickly, resulting in a time delay.
Another major drawback is that the amount of pulverized coal cannot be adjusted individually for each of the plurality of grain burners.

As another method, when supplying powdered coal to multiple burners by air flow from one powdered coal storage tank, the entire supply amount is weighed with one measuring device installed under the powdered coal storage tank. is air-flowed and branched into multiple pipes along the way.
There is a method to increase or decrease the flow rate using a valve installed in the middle of the branch pipe, but it is not easy to accurately measure the concentration of coal contained in the flow rate air, and pulverized coal can easily adhere to the valve and become a source of ignition. There were many control and safety problems.

In addition, if a measuring device corresponding to the number of concentrate burners is installed under one fine coal storage tank, and the fine coal is air-flowed from each measuring device to each concentrate burner, the individual supply amount can be adjusted arbitrarily. However, it had major disadvantages such as being extremely uneconomical and subject to space constraints. The present invention solves the above-mentioned drawbacks, and allows the supply ratio of pulverized coal supplied to each burner to be arbitrarily changed in a own-port furnace having a plurality of large-scale coal burners, and the total supply amount can be adjusted to a desired set value. By opening a feed port for pulverized coal in the middle of the conventionally used coal burner that supplies concentrate, hot air, and heavy oil, it can be used as a fuel without major modification of the conventional concentrate burner. The purpose is to provide a pulverized coal supply device for a double blast furnace that allows the use of only heavy oil, only pulverized coal, or both heavy oil and pulverized coal.

In order to achieve the objects of the present invention, the present invention constitutes the apparatus described in the claims.

A detailed explanation will be given below according to the drawings.

In FIG. 1, reference numeral 1 denotes a shaft portion of a self-slow furnace, and a plurality of concentrate burners 2 are provided at the shaft end.

The rice cake burner 2 is provided with a concentrate charging chute 3, an oil burner 4, and a hot air blast pipe 5 so as to join together at the top of the shaft. It is arranged to join the 2nd.
7 is a pulverized coal storage tank into which coal pulverized by a coal pulverizer (not shown) is sent.

8 is a feeder for discharging the pulverized coal storage tank 7, which is operated intermittently; 9 is a feeder for receiving and weighing the fine coal discharged from the feeder for discharging 8; and discharging it so as to maintain the amount of fine coal within a predetermined upper and lower limit range. A measuring device that adjusts the operation interval of the feeder 8, and a discharge feeder from the metering device 9 can continuously cut out the amount set by calculation, and the cutting amount can be changed as the calculated amount changes. This is how it is.

Reference numeral 11 denotes a distributor that receives the coal from the discharge feeder 10 and distributes it to the pulverized coal charging chute 6, which is a weighing device 1 of Magnesel.
2 so that the total weight of the distributor 11 can be measured.

2 and 3 are drawings showing the internal structure of the distributor 11,
A perforated plate 13 is provided above the bottom of the cylindrical tank-shaped distributor 11 so as to divide the inside of the distributor 11 into upper and lower parts, and the air is blown under pressure by a blower 14 provided outside the distributor 11. Air is supplied to the lower side of the perforated plate 13 of the distributor 11, and the air is blown upward from the perforated plate 16 through a canvas 15 provided in contact with the lower surface of the perforated plate 13. There is.

The perforated plate 13 has a number of holes 1 equal to the number of concentrate burners 2.
7 is open, and the rotation speed of each droplet 17 can be adjusted by a pipe 18. The outlet of the rotary valve 19 merges into the chute 6 for charging fine coal. Reference numeral 20 denotes a total weight controller which is operated by a measurement signal from the Magnesel weighing device 12 and increases or decreases the rotational speed of the rotary valve 19 via a proportional setting device 21.

The proportional setting device 21 is a device for setting the rotation speed of each rotary valve 19 independently, and the rotary valve 22 controls the rotation speed instruction signal from the total weight controller 20 according to the setting signal set by the proportional setting device 21. Valve 1
9 rotation speed controller. In this embodiment, the number of coal burners 2 is four, and the capacity of each rotary valve 19 is 1/2 of the total maximum amount of pulverized coal to be supplied to the flash furnace shaft section 1.
The proportional setting device 21 of each rotary valve 19
The supply ratio to other rotary valves can be adjusted within the range of 0 to 1.0. Next, how to use such a device will be explained. The weight of pulverized coal charged into the blast furnace is changed as necessary to maintain the composition and amount of the raw material used, the target grade of matte, and the temperature of the produced melt at the desired values. However, if the fuel used is heavy oil in addition to pulverized coal, it will vary depending on the amount of heavy oil used. The pulverized coal stored in the pulverized coal storage tank 7 is sent to the weighing machine 9 by intermittent operation of the discharge feeder 8, and the discharge feeder 101 installed at the bottom of the weighing machine 9 discharges the pulverized coal per unit time set by calculation. pulverized coal is continuously supplied to the distributor 11 in an amount corresponding to the supply amount. The fine coal that has entered the distributor 11 is transferred to the perforated plate 13 by the pressure air from the blower 14.
The specific gravity of the cage is made uniform, and the discharge volume caused by the rotation of the rotary valve 19 is in good proportion to the discharge amount of fine coal. If you want to increase the amount of pulverized coal supplied due to a change in the raw material formulation, a change in the target plow quality, or a change in the produced plow temperature from the target value, operate the discharge feeder 10 and move it from the discharge feeder 10 to the distributor 11. Increase the amount of pulverized coal supplied to If the rotational speed of the rotary valve 19 remains the same as before, the amount of retention in the distributor 11 will increase, so the total weight controller 20 constantly controls the distributor 11.
In order to keep the weight of the distributor 11 at the set weight, a speed increase command is issued to the rotation speed controller 22 of the rotary valve 19 via the proportional setting device 21 to uniformly increase the speed of the rotary valve 19. The speed increase command to return to the set weight is stopped, and the discharge amount of the feeder 10 and the discharge amount of the rotary valve 19 are balanced. Also, even if the amount supplied from the discharge feeder 10 to the distributor 11 does not increase or decrease, the heat load in the own port furnace shaft will increase locally, and for example, the amount of concentrate and fuel supplied to one concentrate burner will increase. When control is desired, the proportional setting device 21 corresponding to the concentrate burner is operated to lower the set value.

The signal from the proportional setting device 21 reduces the rotation speed of the corresponding rotary valve 19, so if this continues, the total amount of pulverized coal discharged to the shaft will decrease, and the amount of stagnation in the distributor 11 will increase. . Therefore, in order to keep the weight of the distributor 11 the same, the proportional setting device 21 is controlled by the total weight controller 20.
A speed increase command is issued to the rotational speed controller 22 of each rotary valve 19 via the controller to uniformly increase the rotational speed of each rotary valve 19 according to the set ratio, and when the weight of the distributor 11 returns to the previous value. The speed increase command is stopped to balance the discharge amount of the discharge feeder 10 and the total discharge amount of the rotary valve 19. The above describes the case of increasing the rotary valve, but on the other hand, when operating the discharge feeder 10 to decrease the amount of pulverized coal supplied or increasing the supply ratio of a specific burner, the distributor 11 In order to keep the retention amount constant, a deceleration command can be issued to the rotation speed controller of the rotary valve.

Since the present invention is configured as described above, it is possible to easily improve a burner that conventionally used only heavy oil to use both heavy oil and fine coal, or to stop the supply of heavy oil and supply only fine coal. Since the supply amount of pulverized coal can be changed quickly with relatively simple equipment, it is possible to quickly respond to fluctuations in the furnace.

Note that the magnet cell for measuring the weight of the distributor may be a load cell.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a pulverized coal supply device for a flash furnace according to the present invention, and FIG. 2 is a cross-sectional view of an example of a distributor above a perforated plate.
FIG. 3 is a sectional view taken along the line A--A in FIG. 2. 1... Shaft part of the blast furnace, 2... Charse burner, 3... Charging chute, 4... Oil burner,
5...Hot air blast pipe, 6...Chute with powdered coal bag, 7...Pulverized coal storage tank, 8...
Discharge feeder, 9...Measuring device, 10...
...Discharge feeder, 11...Distributor, 12
...Weigher, 13... Perforated plate, 14.
...Blower, 15...Campus, 16
... Hole, 17 ... Ochiguchi, 18 ...
・・・・／ Type, 19・・・・・・〇-Tally valve, 2
0...Gross weight controller, 21...Proportional setting device, 22...Rotation speed controller. Figure 3 Crocodile↑Figure 2

Claims (1)

[Claims] 1. A discharge feeder that receives pulverized coal from a pulverized coal supply source and can adjust the cutting of pulverized coal, and a plurality of discharge feeders that are provided to receive pulverized coal from the discharge feeder and discharge the supplied pulverized coal while causing air flow. a plurality of rotary valves connected to a pulverized coal charging chute with an outlet connected to each outlet of the distributor to join a concentrate burner; A weighing device that measures the weight of the rotary valve and sends out the measured weight as a signal, a plurality of rotation speed controllers connected to each rotary valve to control the rotation speed of the rotary valve, and a rotation speed controller an adjustable proportional setting device that adjusts the rotation speed controller, and a plurality of rotation speed controllers connected to the proportional setting device when the weight measured by the weighing device increases or decreases according to the send signal of the weighing device. and a total weight controller connected to a scale and a proportional setting device. Furnace pulverized coal feeding device.