KR850001180B1 - Equipment pre-heating of sub-row meterial for steel marking - Google Patents

Abstract

A gate(26) is located at the sub-raw material discharge pipe(24), and is opened and closed according to furnace temperature. Another gate(30) is located at the bottom of the subraw material casting preparatory hopper(27), and it is controlled automatically according to the weight of the material as measured by the sub-raw material weight-measuring equipment. The automatic control equipment comprises a thermocoupler(32), which measures the temperature of molten steel in the electric furnace; a temperature detector, which checks the electromotive force according to the measured temperature; a central control part, and a control panel.

Description

Automatic preheating facility for auxiliary raw materials in steelmaking

1 is a perspective view showing an embodiment of the present invention.

2 is a waste gas flow diagram of the installation of the present invention.

3 is a feedstock system diagram of the installation of the present invention.

4 is a schematic diagram of a control device.

5 is a block diagram of a control device.

6 (a) and 6 (b) are flowcharts showing the operational procedures of the present invention.

* Explanation of symbols for main parts of the drawings

1: Sub-material preheating room 4: Sub-material receiving space

5: waste gas circulation space 6: aeration hole

8: stack 9: waste gas introduction pipe

10: waste gas steering cone 11: waste gas discharge pipe

12: heat storage chamber 13: stack

14: synchronous motor 15: turnover

16: motor 17: backflow prevention

19: Hopper 20: auxiliary raw material supply pipe

22, 25, 29: vibration cylinder 23, 26, 30: gate

24: secondary raw material discharge building 27: secondary raw material preparation hopper

31: secondary raw material weighing device 32: thermocouple

33: temperature detection device 34: computer device

35 control panel

The present invention preheats the secondary raw materials pre-heating during steelmaking to preheat the secondary raw materials to be put into the smelters and oxidizers and reducers in the steelmaking by using the high temperature of the waste gas generated in the electric furnace and to quantitatively input the secondary raw materials required for each period. It is about a facility.

In general, steelmaking, especially cast steel, dissolves the main raw material into an electric furnace, and dissolves deoxidation by adding quicklime to the used molten steel to oxidize dephosphorization and carbon, followed by quicklime, Fe-Si, quicklime and Fe-Mn. It is divided into a refining group consisting of a reductor for desulfurization and adjustment of ingredients, and conventionally, the subsidiary materials input to the refiner are manually added at room temperature or preheated by a separate heat source and manually added. The waste gas was released as it is.

Therefore, conventionally, the amount of heat required to warm subsidiary materials from room temperature to the melting point temperature depends on arc heat in an electric furnace or a separate member, resulting in high heat loss during steelmaking. It was not possible to efficiently use, and when the subsidiary materials were added at room temperature, the time until the subsidiary materials were dissolved was long, so the interfacial reaction time between the molten metal and the slag was shortened relatively, resulting in the degradation of the steel due to the decrease in the reactivity in the furnace. Depending on the experience of the operators, there were problems such as a decrease in productivity and a large amount of non-uniformity and defective products caused by manual input.

The present invention eliminates these conventional problems, preheat the secondary raw materials using high-temperature waste gas generated in the furnace, and by automatically inserting the appropriate amount of secondary raw materials at the appropriate time, steelmaking that can improve energy saving, productivity and steel quality It is to provide automatic preheating equipment for municipal raw materials.

In the drawing, reference numeral 1 denotes an auxiliary material preheating chamber, which is composed of an inner wall 2 and an outer wall 3 composed of fireproof walls and steel plates, and an inner wall 2 has a secondary material receiving space 4 and a waste gas circulation space ( Many ventilation holes 6 communicating 5) are laid.

Since the upper surface of each sub-raw material preheating chamber 1 is an existing facility, the waste gas flows into the sub-raw material receiving space 4 below the inlet hole of the waste gas introduction pipe 9 communicated in the middle of the stack 8 of the electric furnace 7. Waste gas steering cone 10 to control the is installed.

A waste gas discharge pipe 11 is installed at a lower end of the waste gas circulation space 5 of each sub-raw material preheating chamber 1, and the discharge pipe 11 is connected to a stack through a heat storage chamber 12 composed of heat storage lead and the like. 13) and open to the atmosphere through the existing dust collector (not shown).

At the connecting portion of the existing stack 8 and the waste gas inlet pipe 9, a switching block 15 driven by the synchronous motor 14 is installed, and the stack 13 is electrically connected to the synchronous motor 14. When the switching damper 15 starts the closing of the stack 8 and opening of the introduction pipe 9 by the connected motor 16, the stack 13 is opened, and the dam 15 is introduced into the introduction pipe 9. ), A backflow prevention dampa 17 for closing the stack 13 is provided.

The upper part of the sub-raw material preheating chamber 1 is provided with a hopper 19 for supplying the sub-raw material transferred by the conveyor 18 to the pre-heating chamber 1, and each pre-heating chamber 1 in the lower opening of the hopper 19. The secondary raw material supply pipe 20 for selectively supplying the secondary raw material to the branch) is branched and in communication with each other, the lower end of each supply pipe 20 by the vibration cylinder 22 vibrated by the compressed air supplied from the compression pump 21 The movable gate 23 is built in.

At the lower end of each sub-raw material preheating chamber 1, a sub-raw material discharge pipe 24 is installed in communication with the sub-material accommodating space 4, and a gate 26 vibrated by the vibrating cylinder 25 is provided at 24, respectively. .

A secondary raw material preparation hopper 27 is installed below the open end of the secondary raw material discharge pipe 24, and the lower opening of the hopper 27 communicates with the secondary raw material input pipe 28 connected to the electric furnace 7, and vibrating cylinder The gate 30 vibrated by 29 is provided.

At the lower end of the auxiliary material preparation preparation hopper 27, a weighing device 31 for storing the weight of the auxiliary material supplied on the hopper 27 is provided.

The dams 15 and 17 and the gate 23 are manually operated by an operator, and the gates 26 and 30 are thermocouples 32 and thermocouples for measuring the temperature of the molten steel of the electric furnace 7. 32, each gate according to the electric signal from the temperature detector 33 and the temperature detector 33 for checking the electromotive force according to the temperature measured in 32 and the electric signal from the sub-material weighing device 31 It is automatically controlled by a control device composed of a weight control unit 34 which instructs to drive) 30 and a control panel 35 which controls these devices.

As shown in FIG. 5, the gates 26 and 30 are opened and closed by a signal according to the temperature measured by the thermocouple 32 and a signal according to the weight measured by the weighing device 31.

That is, the signal according to the temperature measured in the thermocouple 32 is converted into a digital signal in the A / D converter is input to the CPU through the I / O port of the central control unit 34, when the signal and the set temperature is matched, The command signal from the CPU is converted into an analog signal through the D / A converter at the I / O port and transmitted to the gates 26 and 30 through the automatic control panel 35 so that the gate 26 is opened. The gate 30 is closed.

When the gate 26 is opened, the sub-raw material preheated in the preheating chamber 1 is loaded into the preparation preparation hopper 27, the weight thereof is measured by the weighing apparatus 31, and the A / D converter is used as an electrical signal. It is converted into digital signal and input to Cpu through I / O port. When the signal is accumulated and the set value is reached, the command signal from Cpu is converted into analog signal through D / A converter at I / O port. The gate 26 and 30 are closed through the control panel 35 and the gate 26 is closed, and the gate 30 is opened so that the weighing of the subsidiary material is completed and the subsidiary material is introduced.

When the addition of the subsidiary materials is completed, the gate 30 is also closed again and continues to the next step. In the next step, the operation is repeated.

Reference numeral 36 is a control valve such as a solenoid valve for selectively supplying compressed air in the compression pump 21 to each movable part, and 37 is a heat collecting device of an existing installation.

The present invention is composed of the above structure, it will be described the operation according to the steelmaking combination below.

After leaving the molten steel last time, after completing simple repairs, the main raw material is loaded with scrap iron, and electric power is input to start the melting operation.

Since the waste gas of the work is not distributed and is lower than the refiner waste heat, it is not used for preheating of the subsidiary materials, and the stack 13 is closed by the waste gas introduction pipe 9 and the dampa 17 by the dam wave 15 and Open the stack (8) as a facility to suck the waste gas into the existing dust collector (not shown) as it is to be discharged to the atmosphere. (Flowchart Block 51)

The waste gas introduction pipe 9 and the stack 13 are closed by the dampa 15 and 17 during the dissolving and tapping-repair period, and the raw materials are raw with the conveyor 18 while the stack 8 is opened. The gate 23 installed in the known sub-raw material supply pipe 20 connected to the supply hopper 19 is selectively opened manually according to the type of the sub-raw material to fill the sub-raw materials in each sub-raw material preheating chamber 1 by type (block 51). When filling is complete, the gate 23 is closed (block 52).

In order to use the high-temperature waste gas generated in the refinery after melting after the melting of the main raw material, the synchronous motors 16 and 14 are operated to close the existing stack 8 with dampers 15 and 17. The waste gas introduction pipe 9 and the stack 13 after the heat storage chamber 12 are opened to inhale high-temperature waste gas into the subsidiary preheating chamber 1, and the induced high-temperature waste gas is conical waste. The gas steering cone 10 adjusts to distribute evenly in the sub-raw material preheating chamber 1.

The high-temperature waste gas drawn into the secondary raw material preheating chamber (1) is a direct preheating and waste gas circulating space for recovering waste heat between the secondary raw material particle gap and through the vent hole (6) through the waste gas circulation space (5). Forced heat exchange system according to the effect of the refractory brick construction of the inner wall (20) made between the vent hole 6 and the waste gas circulation space (5) between the exhaust gas discharge pipe 11 is led to the heat storage chamber along the (5) Indirect preheating by means of two waste heat recovery methods to preheat the various sub-materials filled in the sub-material preheating chamber (1) to 650 ° -850 ° C (block 52).

After that, the waste gas is led to the heat storage chamber 12 having a known configuration through the waste gas discharge pipe 11, and the residual heat is stored in the heat storage softening of the heat storage chamber 12, and the stack 13 and the dust collector (not shown). Through the atmosphere.

After dissolving, calculate the amount of subsidiary materials considering the loading of main raw material, chemical composition of target product and chemical composition of molten steel at the time of melting, and divide oxidizer and reducing group in refiner into 3-4 stages to The input timing of the subsidiary materials and the types of the subsidiary materials are set in the program of the central control unit 34 and stored (block 53).

In the flowchart of FIG. 6 (a) and FIG. 6 (b), three kinds of subsidiary materials SM ₁ , SM ₂ and SM ₃ are divided into three stages (STEP ₁ ) and (STEP ₂ ) (STEP ₃ ). This is an example of steel making.

In block 54, 55, for example, step (STEP ₁ ) corresponds to the oxidizer in the refiner, step (STEP ₂ ) (STEP ₃ ) corresponds to the reducing group, the subsidiary material SM ₁ is quicklime and the subsidiary material SM ₂ is Fe -Si, the subsidiary material (SM ₂ ) is Fe-Mn.

Subsidiary material input temperature (molten steel temperature) in each step (STEP ₁ ) (STEP ₂ ) (STEP ₃ ) is set according to the operation pattern, the temperature corresponding to the oxidizer during steelmaking is about 1580 ℃, one stage of the reducing machine Is about 1600 ° C, and the second step is 1260 ° C, so that the set temperatures ST ₁ (ST ₂ ) and ST _{3 of} each step are calculated and set according to the operation pattern.

In addition, the step feed amount (weight) of the step by step is also determined according to the steelmaking pattern, and the numerical expression is avoided here, and is displayed as a symbol.

That is, the input amount of the subsidiary material SM ₁ in step STEP ₁ is represented by SW ₁₁ , and the input amounts of the subsidiary material SM ₁ and SM ₂ in step STEP ₂ are represented by SW ₁₃ and SW ₃₃ , respectively ( Block 54,55).

Subsidiary materials are continuously preheated while the refiner is in progress, and when the operator selects the corresponding program for the refiner stage in (Cpu) of the central control unit 34, the temperature detector 33 according to the molten steel temperature measurement by the thermocouple 32 is performed. the detected temperature (MT ₁₎ is to be converted to electrical signals and transmitted to the central controller 34 (block 56), the measured temperature (MT ₁₎ is set in the step (sTEP ₁₎ haenoteun preset temperature (ST ₁₎ As soon as possible, the central control unit 34 issues a command to the automatic control panel 35 according to the set program (block 57), and preheats one kind of sub-material SM ₁ accommodated according to the order determined in the program of the corresponding step (STEP ₁ ). The gate 26 of the sub-material discharge pipe 24 at the lower end of the chamber 1 is opened (block 58).

The preheated sub raw material SM ₁ is placed in the sub raw material input preparation hopper 27 through the sub raw material discharge pipe 24 and weighed by the weighing device 31 (block 59), and the weight of the sub raw material (MW ₁ ) is centrally controlled. When the sub-material is detected at 34 and approaches the set weight SW ₁₁ , the vibrating cylinder 25 of the gate 26 is vibrated to gradually narrow the opening degree of the gate 26 to close the discharge pipe 24 to accumulate excess sub-material. (Block 60), when the weighing of the subsidiary material SM ₁ is completed (SW ₁₁ = MW ₁ ), the command signal from the central control unit 34 is transmitted to the cylinder 29 through the automatic control panel 35. In addition, the gate 30 is opened and the subsidiary material SM ₁ is injected into the molten steel interface in the electric furnace 7 through the subsidiary raw material input pipe 28 (block 61).

When the input of the subsidiary material SM ₁ of the first step STEP1 is completed, the gate 30 is closed by the command of the central controller 34. (Block 62).

When the input of the first stage _secondary raw material is completed and the temperature MT _{2 of the} molten steel reaches the set temperature ST ₂ of the step (STEP ₂ ) (block 57), the same procedure as in the first step (STEP ₁ ) described above is performed. step additives (SM ₁₎ (SM ₂₎ and the input (block 58,59,60,61,62), to input the subsidiary materials (SM ₁₎ (SM ₂₎ of the back step 3 (sTEP ₃₎ (block 57 , 58,59,60,61,62).

Here, in step 2 (block 63) and step 3 (block 64), there are two types of sub-materials. First, the sub-materials (SM ₁ ) are weighed according to the blocks 58, 59, 60, and then in the same order, the sub-materials (SM ₂ ) or After weighing (SM ₃ ), add them together and complete loading according to blocks 61 and 62.

That is, in step 2 (STEP2) measured and the accumulated weight (MW2) this is to input when a match to the set weight (SW ₁₂ + SW ₂₂₎ of the subsidiary materials (SM ₁₎ and (SM _2), 3 in the step (STEP ₃₎ It is input when the measured cumulative weight (MW ₃ ) is equal to the set weight (SW ₁₃ + SW ₃₃ ) of the subsidiary materials SM ₁ and SM ₂ .

In this way, the chemical composition of the molten steel required by the refining machine reaches the target component, and when the tapping temperature is reached, the molten steel is pulled out and the operation is completed once.

The gates 26 and 30 may be installed to be manually operated in consideration of the functional factory startup of the central control unit 34 and the automatic control panel 35.

As described above, according to the present invention, the high-temperature waste gas generated in the electric furnace is introduced into each sub-material preheating chamber, thereby preheating the sub-materials, thereby greatly reducing the amount of heat required for heating the sub-materials, and by adding preheated sub-materials, molten steel and slag and The reaction time of the can be extended to improve the rigidity due to the improvement in the furnace reactivity.

In addition, by appropriately inserting the appropriate amount of subsidiary materials in a timely manner, it is possible to improve the quality of steel and simplify the operation, thereby reducing the production cost.

Claims (3)

(Twice correction) Sub-material receiving space (4) and communicating with the stack (8) through the waste gas introduction pipe (9) and the secondary material discharge pipe 24 is installed at the bottom, the waste gas steering cone (10) is installed therein; The waste gas circulating space 5 connected to the known heat storage chamber 12 in which the stack 13 is installed through the waste gas discharge pipe 11 is provided with a sub-raw material preheating chamber 1 in communication with the vent hole 6. , The subsidiary material supply hopper 19 connected to the receiving space 5 is installed in the lower part of the subsidiary material supply hopper 19 and the preheating chamber 1 installed with a branch and the subsidiary material input preparation hopper communicating with the subsidiary material input pipe 28 ( 27), the switching pipe (15) is installed in the communication portion of the introduction pipe (9) and the stack (8) and the reverse flow prevention dam (17) in the stack (13), respectively, the discharge pipe (24) and the hopper The gate 26 and 30 are respectively provided at the discharge end of the 27, and the sub-material weight measuring device 31 is installed at the lower part of the hopper 27. Secondary material preheating automatic input equipment. According to claim 1, wherein the gate (26) installed in the subsidiary material discharge pipe (24) for opening and closing control at each time according to the temperature in the furnace, the subsidiary weighing device to the gate (30) installed at the lower end of the auxiliary raw material preparation hopper (27) An automatic pre-heating device for pre-heating of raw materials for steelmaking, characterized in that an automatic control device for opening and closing control at different times is installed in the measured value of (31). The temperature control device 32 and the temperature sensing device 33 of claim 2, wherein the automatic control device checks the thermocouple 32 for measuring the temperature of the molten steel of the electric furnace and the electromotive force according to the temperature measured by the thermocouple 32. The preliminary raw material pre-heating during steelmaking is characterized in that it comprises a central control unit 34 for generating the opening and closing signal of each gate in accordance with the electrical signal and the measurement value in the sub-material weighing device 31 and a control panel 35 for controlling them. Automatic dosing device.

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