JP2001304773A - Powder-supplying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply a powder and gas from an individual powder-supplying machine to a plurality of ports uniformly and stably when blowing the powder into the container of a refining furnace, a melting furnace, or the like individually or mixedly along with the gas to be carried. SOLUTION: In the powder-supplying device for blowing the powder from a port 5 to a container 4 individually or mixed along with the gas to be carried, an orifice 7 with a sectional area that is equal to or less than the maximum value of the inner sectional area of a channel from piping after a distribution box 6 or a branch pipe to the port 5 is mounted to the middle of each piping at the port side of the distribution box 6 or the branch pipe for supplying powder to a plurality of ports 5, or to each outlet part of the distribution box 6. Hard metals, hard ceramics, or hard sintered materials that are fully durable to powder wear are preferably used as orifice materials.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a smelting furnace such as a blast furnace, an electric furnace, a converter, a cupola, a reducing furnace, a semi-reducing furnace, a refining furnace, a hot metal ladle, a molten steel ladle, and a mixed iron in a steel manufacturing process. Containers such as cars, mixed iron furnaces or preheating furnaces store coal, coke,
The present invention relates to a powder supply apparatus for blowing powder such as quicklime, slaked lime, dust, ore, or the like, alone or as a mixture, and blowing the powder from a tuyere with a carrier gas.

[0002]

2. Description of the Related Art In the steel manufacturing process, particularly in the process of manufacturing hot metal and molten steel, various melting furnaces, refining furnaces, reduction furnaces,
A preheating furnace or the like is used. In these furnaces, a device for blowing gas / powder through the tuyere into the furnace is installed.
For example, in a converter, inert gas, oxygen and cooling gas, carbon dioxide gas, etc. are blown through a bottom tuyere, and sometimes quick lime powder is blown into the molten metal in the furnace from the bottom tuyere together with oxygen gas. is there. When a large amount of scrap is melted or iron ore is melt-reduced in the furnace, coal powder is blown into the furnace together with the carrier gas from the bottom tuyere, the side wall tuyere, or the tuyere of the furnace shoulder. Things are going on. Furthermore, in the case of a molten steel ladle, a hot metal ladle, a mixed iron wheel, etc., it was conventionally only a container for transporting hot metal or molten steel. To perform refining such as desulfurization and dephosphorization. Also, in an electric furnace, coke powder and quick lime are blown into scrap or molten metal or slag through a consumable lance, or coke powder transported to oxygen gas or inert gas from a fixed tuyere at a furnace wall or a furnace bottom. It started to blow into the furnace. In cupolas that dissolve scraps, ferroalloys, etc., normal air or oxygen-enriched air is blown from the tuyeres,
At times, coke powder, coal powder or the like is injected into the furnace together with the carrier gas as fuel.

[0003] When only fuel gas such as oxygen, nitrogen, argon, carbon dioxide gas, LPG / COG, etc. is blown through a tuyere into such a melting furnace / refining furnace, a flow control device of one system is usually provided for one tuyere. For example, a flow regulating valve, a shutoff valve and the like are provided. However, when the number of tuyeres is large, there is a case where a gas is supplied to a plurality of tuyeres by branching a flow path in the middle of a pipe for a flow control device of one system. In this case, usually, after branching, an orifice with a reduced internal cross-sectional area of the pipe is installed at a position as close as possible to the tuyere, and by applying pressure loss to the piping system, the gas supplied to multiple tuyeres can be evenly distributed. Aim.
In this case, as the orifice, a ring-shaped plate made of stainless steel is used like the orifice usually used in a flow meter or the like.

On the other hand, quicklime powder, slaked lime powder, coke powder,
When blowing powder alone, such as coal powder, dust powder, ore powder, fluorite powder, and other flux powder, or a mixture of these powders through a tuyere or nozzle of a furnace such as a melting furnace or a refining furnace together with carrier gas, More specifically, the powder is supplied from one powder feeder to one tuyere through one piping system. In general, the powder feeder has a configuration in which a blowing tank and a cutout device are combined, and as a cutout device, there are a rotary feeder type, a table feeder type, a flow differential pressure control type, and the like.・
It is appropriately selected in consideration of properties, required control level, installation location conditions, and the like. However, when there are a large number of tuyeres of a furnace, there is a method of branching into a plurality of systems within one powder supply device, passing through a plurality of piping systems, and supplying the powder to each tuyere connected thereto. . In addition, the powder is conveyed from the powder supply device to the vicinity of the furnace by a single pipe, distributed to a plurality of pipes through a distributor, and supplied to each tuyere connected thereto. Sometimes. The latter distribution method is
The present invention is applied to a case in which the number of tuyeres is large, thereby reducing the equipment cost of the powder supply apparatus, and a case where a plurality of pipe supply paths cannot be installed because the furnace is of a movable type (rolling type).

[0005]

As described above, when the number of tuyeres is large, the flow control device of one system is
The gas may be supplied to multiple tuyeres by branching the flow path in the middle of the pipe.However, after branching, an orifice with a reduced internal cross-sectional area of the pipe is installed at a position as close to the tuyere as possible, By applying pressure loss to the system, the gas supplied to the plurality of tuyeres is evenly distributed. As the orifice in this case, a stainless steel ring-shaped plate is used like the orifice usually used in a flow meter or the like. However, in the case of a powder supply pipe, an orifice made of stainless steel is worn out in a short time and cannot be evenly distributed. If the orifice is not installed, the metal that is generated and adhered to the tuyere tip of the melting furnace or the like gradually closes the flow path cross section, and finally the tuyere tip may be completely closed.

When the powder supply pipe is branched in the middle to supply the powder to a plurality of tuyeres, care is taken so that the powder is evenly distributed to each tuyere using the aforementioned distributor. But,
Also in this case, since the orifice is not used, gas and powder are not evenly distributed due to the growth of the metal at the tip of the tuyere. In particular, when there is a timing at which only the gas is blown at the same tuyere and a timing at which the powder is blown together with the carrier gas, at the timing at which the powder is blown, the metal growth tends to be suppressed due to the wear of the tuyere tip metal by the powder. However, at the timing when only gas is blown, the metal at the tip of the tuyere tends to grow, which promotes uneven distribution of gas and powder.

Due to the non-uniform generation and growth of the tuyere tip metal between each tuyere and the tuyere clogging, the originally required flow rate of the blown gas and the supply amount of the powder are not secured, so that the processing performance and metallurgical effect are reduced. This has not been demonstrated, and the processing time has been greatly extended, which has been a major problem in equipment and operation.

An object of the present invention is to solve these problems.

[0009]

Means for Solving the Problems The present invention provides the following (1)-
It is as (4).

(1) In a powder feeder for blowing powder into a container from a tuyere together with a carrier gas or a mixture of powders, each of the distributors or branch pipes on the tuyere side of a distributor or a branch pipe. A powder characterized in that an orifice having a cross-sectional area equal to or less than the minimum value of the internal cross-sectional area of the flow path from the pipe after the distributor or the branch pipe to the tuyere is attached in the middle of the pipe or at each outlet of the distributor. Body feeding device.

(2) The powder supply apparatus according to (1), wherein a hard metal, a hard ceramic, or a hard sintered material having sufficient durability against powder abrasion is used as a material of the orifice.

(3) The powder supply device according to (1) or (2), wherein the thickness of the orifice in the longitudinal direction of the pipe is 5 mm or more.

(4) The powder supply device according to any one of (1) to (3), wherein the shape of the flow path side of the orifice is a convex shape for smoothing the flow of the powder.

[0014]

FIG. 1 schematically shows an example of a powder supply apparatus according to the present invention. The powder cut out from the blowing tank 1 by the cutting device 2 is supplied to the supply pipe 3 together with the carrier gas.
And supplied to a plurality of bottom-blowing tuyeres 5 by a distributor 6 installed at the bottom of the melting and refining furnace 4. A ceramic orifice 7 having the same inside diameter was installed in each pipe from the outlet side of the distributor 6 to each of the bottom tuyeres.

The bottom-blowing tuyere 5 of the melting and refining furnace 4 is under the molten metal during operation, and blows gas or powder into the molten metal to agitate the molten metal and promote a metallurgical reaction. The blowing of powder into the molten metal is performed during the melting and refining operation, but depending on the operating method, there is a timing at which only gas is blown without blowing powder. As described above, when powder or gas is blown into the molten metal, a base metal is generated and adhered to the tip of the tuyere, and the cross-sectional area of the flow path is reduced. If the depth of the molten metal at the tuyere tip is the same, the gas blowing pressure at the tip is the same, so the gas flow rate or powder flow rate blown from the tuyere tip depends on the cross-sectional area of the opening, depending on the state of metal production. Becomes
This tendency is strong when the gas flows alone, and the unbalance of the tuyere tip cross-sectional area is gradually promoted.

As a means for alleviating such unbalance at the tip of the tuyere, in the example shown in FIG. 1, a ceramic orifice 7 is provided at the subsequent stage of the distributor 6. By adding a pressure loss at the ceramic orifice 7 in the middle of the pipe, the flow rate is not limited by the base metal attachment portion at the tip of the tuyere, but is limited by the ceramic orifice 7 having the same diameter. Evenly distributed to each tuyere. When the gas flow rate and the powder flow rate flowing through each tuyere become uniform, the ingot that is generated and adhered to the tuyere tip is generated or worn almost uniformly. As a result, the uniform generation of the tuyere tip metal and the uniform distribution of gas and powder interact with each other, while ensuring stable gas and powder supply.

FIG. 2 schematically shows another example of the powder supply apparatus of the present invention. The powder cut out from the blowing tank 1 by the cutting device 2 passes through the supply pipe 3 together with the carrier gas, and is supplied to the plurality of bottom blowing tuyeres 5 by the distributor 6 installed at the bottom of the melting and refining furnace 4. You. A ceramic orifice 8 having the same inner diameter was installed at the outlet of each pipe of the distributor 6.

This embodiment is particularly effective when there is no space for installing a ceramic orifice in the pipe between the distributor 6 and the bottom tuyere 5. By disposing the ceramic orifice 8 on the outlet side of the distributor 6, a function of uniformly distributing the gas flow to each tuyere can be added to the distributor 6 itself. Normally, the outlet side of the distributor 6 has a small outlet diameter that is almost the same inside diameter as the pipe connected to each tuyere from the large space of the distributor body, so that the corner portion is inherently easily worn by powder. It has become. In order for the distributor 6 to have an orifice effect, it is necessary to make the cross-sectional area smaller than the minimum flow path cross-sectional area from the distributor outlet side to the tuyere tip, and measures against abrasion at the outlet are indispensable. Therefore, as shown in FIG. 2, by installing the ceramic orifice 8 at the outlet of the distributor 6, it is possible to achieve both wear countermeasures and uniform distribution.

FIG. 3 schematically shows another example of the powder supply apparatus of the present invention. Cutting device 2 from blowing tank 1
The powder cut out of the furnace passes through the supply pipe 3 together with the carrier gas and passes through the branch pipe 9 installed at the bottom of the melting and refining furnace 4.
Is supplied to the plurality of bottom blowing tuyeres 5. A ceramic orifice 10 having the same inner diameter was installed in each pipe from the outlet side of the branch pipe 9 to each tuyere.

In this embodiment, when the solid-gas ratio (the ratio between the powder supply amount and the flow rate of the carrier gas) is low and the distributor is not used, the simple branch pipe 9 is installed to transfer the powder. Often used when distributing. By installing the ceramic orifice 10 having the same diameter at the subsequent stage of the branch pipe 9, uniform generation of the tuyere tip metal and uniform distribution of gas and powder interact, and stable gas and powder supply is secured. Is done.

In the above description, the uniform distribution of powder and gas has been described. However, there are cases where it is desired to intentionally increase or decrease the gas flow rate or powder flow rate flowing to a specific tuyere. In this case, the size of the sectional area of the ceramic orifice may be changed according to the gas flow rate or the powder flow rate flowing through each tuyere.

FIG. 4A is a side view showing an example of a mounting state of the ceramic orifice 11, and FIG. 4B is a front view. The ceramic orifice 11 is attached between the flanges 22 of the pipe 12 and fixed with the bolts and nuts 13. The shape of the ceramic orifice 11 has a smooth convex shape on the inner surface side of the flow channel in order to minimize powder abrasion. Usually, the orifice used for gas flow measurement is a stainless steel plate,
The entry side is strictly dimensioned with an edge. However, in the present invention, since the ceramic orifice 11 aims at equal distribution of the pipe flow rate or the powder flow rate, the dimensions required for gas flow rate measurement and the strictness as the orifice shape are not required, but rather the powder orifice shape is required. It is important that the shape is designed with a focus on the measures against wear. As for the thickness of the orifice, it is necessary to make it thicker than usual in consideration of abrasion.
Good results for the orifice life were obtained with a thickness of preferably 10 mm or more.

As for the material of the orifice, it is necessary to provide abrasion resistance according to the type of powder. Therefore, hard ceramics, which are usually easily available and have high abrasion resistance, are preferred. Hard metals such as WC and hard sintered materials such as WC can also be used depending on the type of powder.

FIG. 5 shows a comparative example in which only gas is blown into the melting and refining furnace 4 from a plurality of tuyere tuyeres 5. A supply pipe 16 provided with a flow control valve 14 and a shutoff valve 15 is piped to the furnace bottom of the melting and refining furnace 4 and distributed to a plurality at a furnace bottom pipe portion.
An ordinary orifice 17 is provided in front of the tuyere 5. When only gas is blown in this way, a stainless steel orifice used for normal gas flow rate measurement can sufficiently achieve the purpose.

FIG. 6 shows a comparative example in which powder is supplied from a single powder feeder 19 to a fixed cupola 18. A plurality of supply pipes 20 from the powder feeder 19 are connected to the side-blowing tuyere 21 of the cupola 18. Although the number of supply pipes 20 increases, when the distance between the powder supply device 19 and the cupola 18 is short, powder can be supplied.

[0026]

According to the present invention, when powder such as coal, coke, quicklime, slaked lime, dust, ore, etc. is blown alone or mixed with a carrier gas into a vessel such as a refining furnace or a melting furnace, a single powder is supplied. The powder and gas can be uniformly and stably supplied from the machine to a plurality of tuyeres such as a melting furnace and a refining furnace. Further, since the base metal generated and attached to the tuyere tip becomes uniform, the opening cross-sectional area of the gas / powder flow path in the base part becomes uniform, and the erosion of the tuyere is significantly reduced. As a result, the operation of the melting furnace and the refining furnace can be stabilized, the yield can be improved, the productivity can be improved, the life of the refractory can be improved, the unit consumption of auxiliary materials can be reduced, and the like can contribute to a significant reduction in production costs. .

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating an example of a powder supply device of the present invention.

FIG. 2 is a diagram schematically showing another example of the powder supply device of the present invention.

FIG. 3 is a view schematically showing still another example of the powder supply device of the present invention.

FIGS. 4A and 4B are a side view (FIG. 4A) and a front view (FIG. 4B) of an example of how a ceramic orifice of the present invention is mounted.

FIG. 5 is a diagram schematically illustrating an example of a conventional gas supply method.

FIG. 6 is a diagram schematically illustrating an example of a conventional powder supply method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection tank 2 Cutting-out device 3 Supply pipe 4 Melting / refining furnace 5 Bottom blowing tuyere 6 Distributor 7 Ceramic orifice 8 Ceramic orifice 9 Branch pipe 10 Ceramic orifice 11 Ceramic orifice 12 Pipe 13 Bolt nut 14 Flow control valve 15 Shut-off valve 16 Supply pipe 17 Orifice 18 Cupola 19 Powder feeder 20 Supply pipe 21 Side-blow tuyere 22 Flange

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C21C 7/072 C21C 7/072 S 4K045 F27B 1/16 F27B 1/16 4K046 1/20 1/20 4K055 3 / 18 3/18 14/16 14/16 F-term (reference) 3F047 AA03 BA08 4K012 BD06 4K013 CB04 CF14 EA02 EA03 EA09 EA12 4K014 AA01 AA02 AA03 AB01 AB03 AB04 AB12 AB16 AC14 AC16 AD12 AD27 4K015 AD06 4K045 AA02 AA03A GC09 RA14 RC06 4K046 AA01 AA03 BA01 CC05 4K055 AA01 AA02 AA03 AA04 MA02

Claims (4)

[Claims] In a powder supply device for blowing powder into a container from a tuyere together with a carrier gas or a mixture of powders, each pipe on the tuyere side of a distributor or a branch pipe for supplying powder to a plurality of tuyeres. In the middle or at each outlet of the distributor, an orifice having a cross-sectional area equal to or less than the minimum value of the internal cross-sectional area of the flow path from the distributor or the pipe after the branch pipe to the tuyere is attached. Feeding device. 2. The powder supply device according to claim 1, wherein a hard metal, a hard ceramic, or a hard sintered material having sufficient durability against powder abrasion is used as a material of the orifice. 3. The thickness of the orifice in the longitudinal direction of the pipe is 5 m.
The powder supply device according to claim 1 or 2, wherein m is at least m. 4. The orifice on the flow path side has a convex shape for smoothing the flow of powder.
4. The powder supply device according to any one of items 3 to 3.