KR101706570B1

KR101706570B1 - Electric furnace

Info

Publication number: KR101706570B1
Application number: KR1020150066707A
Authority: KR
Inventors: 최장규; 정현돈
Original assignee: 주식회사 포스코
Priority date: 2015-05-13
Filing date: 2015-05-13
Publication date: 2017-02-14
Also published as: KR20160133764A

Abstract

An electric furnace is started. An electric furnace according to an embodiment of the present invention includes a heating furnace provided with a refractory material in contact with molten metal, a loop for opening and closing an upper portion of the furnace, A plurality of temperature sensors disposed at predetermined intervals along a circumferential direction of the heating furnace so as to sense the temperature of the refractory; a plurality of lime feed pipes connected to the plurality of lime feed ports to supply lime to the plurality of lime feed ports; , An opening / closing valve provided on the lime supply pipe to selectively supply lime to the plurality of lime injection ports, and an erosion position of the refractory based on the temperature of the refractory detected by the plurality of temperature sensors, And controlling the opening and closing of the opening / closing valve so as to supply the lime to the lime inlet.

Description

Electric furnace {ELECTRIC FURNACE}

The present invention relates to an electric furnace, and more particularly, to an electric furnace having an apparatus for automatically injecting lime into an electric furnace loop.

Generally, an electric furnace is a furnace that heats and melts a metal or an alloy using electricity. When a high voltage is applied to an electrode vertically connected to an upper portion of an electric furnace, high-temperature arc heat is generated and the scrap in the electric furnace is dissolved.

Inside the furnace body of the electric furnace, a refractory consisting of a regular refractory and a monolithic refractory is formed to protect the furnace body from the high temperature molten metal.

This refractory often has a problem in that the lifetime of the electric furnace is shortened because frequent erosion due to the reaction with the slag during the blowing, mechanical abrasion caused by the collision with the material for entrance, the arc radiant heat of the electrode rod, Occurs.

Accordingly, various methods for introducing quicklime into the electric furnace have been proposed to prevent local wear of such refractories.

Korean Patent No. 10-0829967 (published on May 16, 2008)

The embodiments of the present invention are intended to provide an electric furnace capable of prolonging the life of an electric furnace by preventing locally eroded refractories of electric furnaces.

According to an aspect of the present invention, there is provided a heating furnace comprising a heating furnace provided with a refractory contacting with molten metal, a loop for opening and closing an upper portion of the furnace, A plurality of temperature sensors disposed at predetermined intervals along the circumferential direction of the heating furnace so as to sense the temperature of the refractory; a plurality of temperature sensors arranged to supply the lime to the plurality of lime- A plurality of lime feed openings formed in the lime feed pipe to selectively supply the lime to the plurality of lime feed openings and an open / close valve provided in the lime feed pipe to supply the lime to the plurality of lime feed openings, And the lime is supplied to the lime inlet corresponding to the determined erosion position of the refractory And a control unit for controlling the opening and closing of the opening / closing valve so that the opening / closing of the opening / closing valve can be controlled.

The control unit may determine the position of the refractory material corresponding to the temperature higher than the preset temperature as the erosion position based on the temperatures transmitted from the plurality of temperature sensors.

Further, the temperature sensor includes a thermocouple inserted through the refractory from the outside of the heating furnace.

The lime feed ports are arranged at equal intervals along the circumferential direction of the loop, the lime feed pipe is provided at three places, and one lime feed pipe is branched to be connected to each of three adjacent lime feed ports Three branches may be provided.

Embodiments of the present invention extend the service life of the electric furnace by grasping the local erosion of the electric furnace refractory in real time and supplying the lime to the eroded area, as well as prolonging the service life of the electric furnace due to the corrosion of the molten steel due to local corrosion of the refractory. The same facility accident can be prevented in advance.

1 schematically shows an electric furnace working process according to an embodiment of the present invention.
FIG. 2 illustrates a lime dispensing apparatus according to an embodiment of the present invention.
3 shows a temperature sensor disposed in a heating furnace according to an embodiment of the present invention.
FIG. 4 illustrates a lime injection process according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below are provided by way of example so that those skilled in the art will be able to fully understand the spirit of the present invention. The present invention is not limited to the embodiments described below, but may be embodied in other forms. In order to clearly explain the present invention, parts not related to the description are omitted from the drawings, and the width, length, thickness, etc. of the components may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

1 schematically shows an electric furnace working process according to an embodiment of the present invention.

Referring to FIG. 1, an electric furnace 10 according to an embodiment of the present invention includes a heating furnace 12, a heating furnace 12, and an electric arc furnace. It is a device to dissolve.

The heating furnace 12 is provided in the form of a container having an open upper portion capable of receiving a raw material such as scrap or alloy iron therein.

The heating furnace 12 is formed with an iron fiber 12a forming an outer appearance and a refractory 12b for protecting the iron fiber 12a from molten metal on the inner side of the iron fiber 12a. The refractory 12b may include a shaped refractory material and a monolithic refractory material.

The opening provided in the upper part of the heating furnace 12 can be closed by covering the loop 11. [ The loop 11 can seal the opening of the electric furnace 10 from the outside during the operation of the electric furnace 10 and is separated from the upper portion of the electric furnace 10 when the raw material is charged into the electric furnace 10 The opening can be opened.

The electrode 20 includes an electrode and the like, and means a member capable of generating an arc between the raw material and the electrode, regardless of the shape thereof. For example, the electrode 20 may be made of a carbon material, and wear may occur while generating an arc.

The electrode 20 enters the inside of the electric furnace 10 and supplies an electric current to the material to be heated to generate an arc with the material to melt the material.

The electric furnace 10 is divided into an AC electric furnace and a DC electric furnace depending on the type of an applied power source. The AC electric furnace can use three electrodes (R, S, T; 20a to 20c) for generating an arc.

The electrode arm (13) supports the electrode (20).

The hydraulic cylinder 14 supports the electrode arm 13 and moves the electrode arm 13 up and down when the electrode 20 needs to be lifted or lowered.

The electrode arm 13 is connected to the electric power supply unit 16 by a power cable 15.

The power supply unit 16 supplies electric power to the electrode 20 through the power cable 15.

The operation of the electric furnace is performed such that when power is supplied to the electrode 20 after the raw material is placed in the heating furnace 12 and the loop 11 is closed and the electrode 20 is lowered toward the scrap, The power turns into heat. The molten steel begins to be solidified at the bottom of the heating furnace 12 while the raw material is melted.

FIG. 2 illustrates a lime dispensing apparatus according to an embodiment of the present invention. FIG. 3 illustrates a temperature sensor disposed in a heating furnace according to an embodiment of the present invention. FIG. It shows the lime injection process.

2 to 4, the local refractory 12b on the inner side of the heating furnace 12 is locally eroded by the arc heat of the electrode 20 and stirring and vortexing phenomena caused by oxygen blowing.

A plurality of lime injection ports 30 are formed on the upper side of the loop 11 to supply lime to prevent erosion at a portion where localized erosion of the refractory 12b occurs.

The plurality of lime feeding openings 30 may be spaced apart from each other along the circumferential direction of the loop 11. Here, the plurality of lime feeding openings 30 are arranged at nine equal intervals so as to cover the entire refractory 12b.

A plurality of lime feed ports 30 are connected to the lime feed pipe 40 to which lime is supplied.

The lime supplied from the lime supply pipe 40 is injected into the eroded refractory 12b inside the heating furnace 12 through the plurality of lime injection ports 30. [

Three lime feed pipes 40 may be provided and three lime feed pipes 40 are provided with three branch pipes 40a, 40b and 40c connected to three lime feed openings 30 adjacent to each other.

The three branch pipes 40a, 40b and 40c are provided with on / off valves 50 for selectively supplying the respective lime supplied to the corresponding lime inlet 30.

The on / off valve 50 may be provided as a conventional control valve that is electrically connected to the control unit 60 and selectively opens and closes the flow path of the branch pipes 40a, 40b, and 40c.

The heating furnace 12 is provided with a plurality of temperature sensors 70 for sensing the temperature of the refractory 12b.

The plurality of temperature sensors 70 may be disposed at predetermined intervals along the circumferential direction of the heating furnace 12. A plurality of temperature sensors 70 are arranged at nine locations along the circumference of the heating furnace 12 in order to sense the temperature of the refractory 12b at the positions corresponding to the plurality of lime injection ports 30. [

The plurality of temperature sensors 70 may be provided as a thermocouple inserted through the refractory 12a of the heating furnace 12 and in contact with the refractory 12b in contact with the molten metal.

A plurality of temperature sensors (70) are electrically connected to the controller (60).

The plurality of temperature sensors 70 sense the temperature of the refractory 12b and transmit the sensed temperature information to the controller 60. [

The control unit 60 determines the erosion position of the refractory 12b based on the temperature sensed by the plurality of temperature sensors 70. [

The control unit 60 previously stores temperature data information that changes in accordance with the degree of erosion of the refractory 12b and compares and analyzes the temperature information transmitted from each of the plurality of temperature sensors 70 with a predetermined set temperature, The position of the refractory 12b corresponding to the portion where the high temperature is sensed is determined as the erosion position.

The control unit 60 opens the opening and closing valve 50 provided in the lime inlet 30 corresponding to the erosion position of the refractory 12b and ejects the lime at the position of the eroded refractory 12b.

Thus, the lime is quickly injected into the position where the erosion occurs during use of the heating furnace 12, thereby preventing local erosion which may occur due to the erosion speed difference of the refractory 12b, The service life can be prolonged.

In addition, it is possible to manage uniform refractories without local corrosion of the refractory 12b of the electric furnace 10, thereby reducing maintenance costs and preventing leakage of external molten steel due to local erosion, thereby reducing the risk of safety accidents .

10: electric furnace, 11: loop,
12: heating furnace, 12a: iron,
12b: refractory, 20: electrode,
30: lime feed port, 40: lime feed pipe,
40a, 40b, 40c: branch pipe, 50: opening / closing valve,
60: control unit, 70: temperature sensor.

Claims

A heating furnace provided with a refractory on a sidewall contacting the molten metal;
A loop for opening and closing an upper portion of the heating furnace;
A plurality of lime injection ports arranged at predetermined intervals along the circumferential direction on the upper side of the loop so as to cover the refractory one area provided on the side wall and supply lime to the refractory as a whole;
A plurality of temperature sensors disposed at predetermined intervals along a circumferential direction of the heating furnace to sense the temperature of the refractory;
A lime feed pipe connected to the plurality of lime feed ports to supply the lime to the plurality of lime feed ports;
An open / close valve provided on the lime supply pipe to selectively supply the lime to the plurality of lime injection ports; And
Closing of the opening / closing valve is controlled so as to determine the erosion position of the refractory based on the temperature of the refractory detected by the plurality of temperature sensors, and to supply the limes to the lime inlet corresponding to the determined erosion position of the refractory And a controller for controlling the operation of the electric furnace.

The method according to claim 1,
Wherein the control unit determines the position of the refractory corresponding to a temperature higher than the set temperature as the erosion position based on the temperature transmitted from each of the plurality of temperature sensors.

The method according to claim 1,
Wherein the temperature sensor includes a thermocouple inserted through the refractory from the outside of the heating furnace.

The method according to claim 1,
Wherein the plurality of lime input ports are arranged at equal intervals along the circumferential direction of the loop,
Wherein the lime supply pipe is provided at three places, and one lime supply pipe is provided with three branch pipes which are branched so as to be connected to three adjacent lime injection ports.