JP6775384B2 - Oxygen cleaning device - Google Patents

Description

The present disclosure relates to an oxygen cleaning device.

A waste melting furnace for melting waste and recovering molten slag is known. In the operation of the waste melting furnace, oxygen cleaning work is performed in the bottom of the furnace. Patent Document 1 discloses an apparatus for performing an oxygen cleaning operation. In this device, a pipe for supplying oxygen is inserted from the outlet of the molten slag to supply oxygen into the bottom of the furnace, and the incomplete molten portion is fluidized by the combustion heat of the pipe itself.

Japanese Unexamined Patent Publication No. 2004-61104

It is an object of the present disclosure to provide an oxygen cleaning device capable of reducing the material consumption of a pipe for oxygen cleaning.

The oxygen cleaning device according to the present disclosure is provided with a pipe for introducing a gas containing oxygen into the melting furnace, and with respect to the first calorific value generated by burning combustible materials in the melting furnace by supplying oxygen through the pipe. The outer diameter and wall thickness of the pipe are set so that the ratio of the second calorific value generated by burning the pipe itself due to the supply of oxygen through the pipe is less than 1 / 2.4.

Conventionally, most of the amount of heat generated by supplying oxygen through a pipe (hereinafter referred to as "total amount of heat generated") has been considered to be the second amount of heat. On the other hand, as a result of analyzing the breakdown of the total amount of heat generated, the following findings were obtained.
a) Most of the total amount of heat generated is not the second amount of heat but the first amount of heat.
b) Even if the oxygen supply amount is increased by increasing the inner diameter of the pipe, the second heat amount does not increase.
c) When the amount of oxygen supplied is increased by increasing the inner diameter of the pipe, the amount of first heat increases.
d) In the existing oxygen cleaning device, the ratio of the second calorific value to the first calorific value is about 12.4.
Based on these findings, the present inventors have increased the ratio of the first heat quantity to the total heat generation amount by adjusting the dimensions of the pipe, thereby reducing the ratio of the second heat quantity to the total heat generation amount, and for oxygen cleaning. We have found that the material consumption of pipes can be reduced. Furthermore, if the pipe dimensions are set so that the ratio of the second calorific value to the first calorific value is less than 1 / 2.4, the material consumption of the pipe for oxygen cleaning is reduced as compared with the existing oxygen cleaning device. I found out what I could do. Therefore, according to the oxygen cleaning device adopting this setting, the material consumption of the pipe for oxygen cleaning can be reduced.

The outer diameter of the pipe is determined to fit with the pipe holder that holds the pipe, and the wall thickness of the pipe is set so that the ratio of the second heat quantity to the first heat quantity is less than 1 / 2.4. You may be. In this case, even when the outer diameter of the pipe is fixed, the material consumption of the pipe for oxygen cleaning can be reduced.

The outer diameter and wall thickness of the pipe may be set so that the inner diameter of the pipe is larger than 16.1 mm. In this case, by increasing the first calorific value, it is possible to reduce the second calorific value, and the material consumption of the pipe for oxygen cleaning can be reduced more reliably.

The outer diameter of the pipe may be 20.7 to 21.7 mm, and the wall thickness of the pipe may be 1.6 to 2.3 mm. In this case, it is possible to reduce the ratio of the second calorific value to the first calorific value to less than 1 / 2.4 while suppressing the decrease in workability due to the decrease in the strength of the pipe.

The outer diameter and wall thickness of the pipe may be set so that the flow rate of gas passing through the pipe is larger than 65 m ³ / h (Normal). In this case, by increasing the first calorific value, it is possible to reduce the second calorific value, and the material consumption of the pipe for oxygen cleaning can be reduced more reliably.

A tubular joint member mounted on the outer circumference of the pipe and joining the pipes to each other by caulking is further provided, and the value obtained by subtracting the wall thickness of the pipe from the wall thickness of the joint member before caulking may be 0.1 mm or less. .. When reducing the wall thickness of pipes, if pipes are joined to each other using existing joint members, a leak may occur at the joint. On the other hand, by adopting a joint member in which the value obtained by subtracting the wall thickness of the pipe from the wall thickness of the joint member before caulking is 0.1 mm or less, the occurrence of leakage at the joint portion can be suppressed.

According to the present disclosure, the material consumption of the pipe for oxygen cleaning can be reduced.

It is a figure which shows the schematic structure of the oxygen cleaning apparatus. It is an enlarged view of the joint part of a pipe. It is a list which shows the evaluation result of an Example / comparative example. It is a graph which shows the evaluation result of an Example / comparative example. It is a list which shows the evaluation result of an Example / comparative example.

Hereinafter, embodiments will be described in detail with reference to the drawings. In the description, the same elements or elements having the same function are designated by the same reference numerals, and duplicate description will be omitted.

The oxygen cleaning device 1 shown in FIG. 1 is a device for performing oxygen cleaning of the bottom 9 of the waste melting furnace. The furnace bottom 9 is located at the bottom of the waste melting furnace and accumulates molten slag (melt) 91 generated by melting the waste. A hot water outlet 9a for taking out the molten slag 91 is provided on the peripheral wall of the furnace bottom portion 9. The molten slag 91 may include a portion having a low degree of melting (hereinafter, referred to as “incomplete molten portion”) 93. The oxygen cleaning device 1 promotes the oxidation reaction in the furnace bottom 9 by supplying oxygen into the furnace bottom 9, and the heat generated by the oxygen cleaning device 1 fluidizes the incomplete molten portion 93.

The oxygen cleaning device 1 has a pipe 2, a pipe holder 3, and an oxygen supply source 4.

The pipe 2 is inserted into the furnace bottom portion 9 from the hot water outlet 9a, and a gas containing oxygen (hereinafter, referred to as “oxygen-containing gas”) is introduced into the melting furnace. The outer diameter D2 and the wall thickness t2 (see FIG. 2) of the pipe 2 are set so that the ratio of the following second calorific value to the following first calorific value is less than 1 / 2.4.
First calorific value: The calorific value generated per unit time when a combustible material (for example, coke 92) in the furnace bottom 9 is burned by oxygen supply through the pipe 2.
Second calorific value: The calorific value generated per unit time when the pipe 2 itself burns due to the supply of oxygen through the pipe 2.
The outer diameter and wall thickness of the pipe 2 may be set so that the ratio of the second calorific value to the first calorific value is 1 / 4.5 to 1 / 2.7, and the ratio is 1/3. It may be set to be 6 to 1 / 3.1. In these cases, it is easy to achieve both the strength of the pipe 2 and the reduction of the material consumption of the pipe 2.

The pipe 2 may be a series of a plurality of pipes. FIG. 1 illustrates a case where the pipe 2 is composed of two pipes 2A and 2B. The pipe 2A has an oxygen supply port 2a on the peripheral wall of the base end portion thereof. The oxygen supply port 2a receives the oxygen-containing gas into the pipe 2. The pipe 2B is joined to the tip of the pipe 2A. Either one of the pipes 2A and 2B may be a portion left unconsumed in the pipe 2 used in the previous oxygen cleaning treatment.

The pipes 2A and 2B may be joined by a joint member 21. That is, the oxygen cleaning device 1 may further include a joint member 21. The joint member 21 is a tubular member that is attached to the outer periphery of the pipes 2A and 2B and joins the pipes 2A and 2B to each other by caulking. The value obtained by subtracting the wall thickness t2 of the pipe 2 from the wall thickness t21 of the joint member 21 (see FIG. 2) before caulking may be 0.1 mm or less.

The pipe holder 3 holds the base end portion of the pipe 2 (the base end portion of the pipe 2A). The pipe holder 3 has a main body 30 and a length measuring device 31. A fitting hole 30a is formed in the central portion of the main body 30. The outer diameter D2 of the pipe 2 is determined to fit with the pipe holder 3. That is, the outer diameter D2 of the pipe 2 is set to a value slightly smaller than the inner diameter of the fitting hole 30a. The outer diameter D2 of the pipe 2 is, for example, 20.7 to 21.7 mm.

In this way, when the outer diameter D2 of the pipe 2 is determined to fit with the pipe holder 3, the ratio of the second heat quantity to the first heat quantity is less than 1 / 2.4. The wall thickness t2 of the pipe 2 may be set. The wall thickness t2 of the pipe 2 may be set so that the ratio of the second calorific value to the first calorific value is 1 / 4.5 to 1 / 2.7, and the ratio is 1 / 3.6 to 3. It may be set to be 1 / 3.1. The wall thickness t2 of the pipe 2 suitable when the outer diameter D2 of the pipe 2 is 20.7 to 21.7 mm is, for example, 1.6 to 2.3 mm, even if it is 1.6 to 1.9 mm. Good. In these cases, it is easy to achieve both the strength of the pipe 2 and the reduction of the material consumption of the pipe 2.

The base end portion of the pipe 2 is inserted into the fitting hole 30a from one side of the pipe holder 3. The length measuring device 31 is fixed to the other side of the pipe holder 3 and is in contact with the base end portion of the pipe 2. The length measuring device 31 has a built-in length sensor that detects the length of the pipe 2. The length sensor is, for example, a microwave range finder, which outputs microwaves, propagates them to the base end of the pipe 2, reflects them at the tip of the pipe 2 (the tip of the pipe 2B), and returns. The total length of the pipe 2 is detected based on the wave.

The oxygen supply source 4 supplies the oxygen-containing gas to the oxygen supply port 2a. The oxygen supply source 4 is, for example, a tank containing a compressed oxygen-containing gas, and is connected to the oxygen supply port 2a of the pipe 2 via a pipe line 40. A valve 41 is provided in the pipeline 40. The valve 41 adjusts the opening degree of the pipeline 40. By adjusting the opening degree of the pipeline 40, the pressure of the oxygen-containing gas at the oxygen supply port 2a can be adjusted.

In the above configuration, the outer diameter D2 and the wall thickness t2 of the pipe 2 may be set so that the flow rate of the oxygen-containing gas passing through the pipe 2 is larger than 65 m ³ / h (Normal), and the flow rate is 70. ~110m ³ / h may be set so that ^(Normal), or may be set to be 80~100m 3 / h (Normal). As an example of the combination of the outer diameter D2 and the wall thickness t2 of the pipe 2 set in this way, there is a combination in which the inner diameter d2 (see FIG. 2) of the pipe 2 is larger than 16.1 mm. However, this combination is based on the premise that the pressure of the oxygen-containing gas at the oxygen supply port 2a of the pipe 2 is about 40 kPa.

As described above, in the oxygen cleaning device 1, the outer diameter and the wall thickness of the pipe 2 are set so that the ratio of the second calorific value to the first calorific value is less than 1 / 2.4. Conventionally, most of the amount of heat generated by supplying oxygen through the pipe 2 (hereinafter, referred to as "total amount of heat generated") has been considered to be the second amount of heat. On the other hand, as shown in Examples and Comparative Examples described later, the following findings were obtained.
a) Most of the total amount of heat generated is not the second amount of heat but the first amount of heat.
b) Even if the oxygen supply amount is increased by increasing the inner diameter of the pipe, the second heat amount does not increase.
c) When the amount of oxygen supplied is increased by increasing the inner diameter of the pipe, the amount of first heat increases.
d) In the existing oxygen cleaning device, the ratio of the second calorific value to the first calorific value is about 12.4.
From these findings, it is possible to reduce the ratio of the second heat quantity to the total heat generation by increasing the ratio of the first heat quantity to the total heat generation by adjusting the dimensions of the pipe 2, and reduce the material consumption of the pipe 2. Found. Furthermore, if the dimensions of the pipe 2 are set so that the ratio of the second calorific value to the first calorific value is less than 1 / 2.4, the material consumption of the pipe 2 can be reduced as compared with the existing oxygen cleaning device. Found. Therefore, according to the oxygen cleaning device 1 adopting this setting, the material consumption of the pipe 2 can be reduced.

The outer diameter of the pipe 2 may be determined to fit with the pipe holder 3 that holds the pipe 2, so that the ratio of the second heat quantity to the first heat quantity is less than 1 / 2.4. The wall thickness of the pipe 2 may be set. In this case, the material consumption of the pipe 2 can be reduced even when the outer diameter of the pipe 2 is fixed.

In order to reduce the ratio in a state where the outer diameter of the pipe 2 is fixed, it is necessary to reduce the wall thickness of the pipe 2. When the wall thickness of the pipe 2 is reduced, the material consumption of the pipe 2 is reduced and the constituent materials of the pipe 2 are reduced. If only the material consumption of the pipe 2 is reduced without changing the constituent materials of the pipe 2, the pipe 2 remaining unconsumed in the oxygen cleaning process becomes long. Since there is a limit to the length of the pipe 2 that can be reused for the next oxygen cleaning process, if too much pipe 2 remains after the oxygen cleaning process, it is necessary to burn the pipe 2 only for the purpose of adjusting the length. There is. On the other hand, in addition to reducing the material consumption of the pipe 2, the constituent materials of the pipe 2 are also reduced, so that the frequency of combustion of the pipe 2 only for the purpose of adjusting the length is reduced. This also contributes to the reduction of material consumption of the pipe 2.

The outer diameter and wall thickness of the pipe 2 may be set so that the inner diameter of the pipe 2 is larger than 16.1 mm. In this case, by increasing the first calorific value, it is possible to reduce the second calorific value, and the material consumption of the pipe 2 can be reduced more reliably.

The outer diameter of the pipe 2 is 20.7 to 21.7 mm, and the pipe wall thickness may be 1.6 to 2.3 mm. In this case, it is possible to reduce the ratio of the second calorific value to the first calorific value to less than 1 / 2.4 while suppressing the decrease in workability due to the decrease in the strength of the pipe 2.

The outer diameter and wall thickness of the pipe 2 may be set so that the flow rate of the oxygen-containing gas passing through the pipe 2 is larger than 65 m ³ / h (Normal). In this case, by increasing the first calorific value, it is possible to reduce the second calorific value, and the material consumption of the pipe 2 for oxygen cleaning can be more reliably reduced.

A tubular joint member 21 which is mounted on the outer periphery of the pipe 2 and joins the pipes 2 to each other by caulking may be further provided. The value obtained by subtracting the wall thickness of the pipe 2 from the wall thickness of the joint member 21 before caulking may be 0.1 mm or less. When reducing the wall thickness of the pipe 2, if the pipes 2 are joined to each other using an existing joint member, a leak may occur at the joint. On the other hand, by adopting the joint member 21 in which the value obtained by subtracting the wall thickness of the pipe 2 from the wall thickness of the joint member 21 before caulking is 0.1 mm or less, the occurrence of leakage at the joint portion can be suppressed.

Although the embodiments have been described above, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made without departing from the gist thereof.

Examples and comparative examples will be described below, but the present invention is not limited thereto.

[First evaluation]
Examples and comparative examples were prepared as follows. In addition, Comparative Example 1 is used in an existing oxygen cleaning apparatus.
Example 1: The pipe 2 is an iron pipe having an outer diameter of 21.7 mm and a wall thickness of 2.3 mm.
Example 2: The pipe 2 is an iron pipe having an outer diameter of 21.7 mm and a wall thickness of 1.9 mm.
Example 3: The pipe 2 is an iron pipe having an outer diameter of 21.7 mm and a wall thickness of 1.6 mm.
Comparative Example 1: The pipe 2 was an iron pipe having an outer diameter of 21.7 mm and a wall thickness of 2.8 mm.
Comparative Example 2: The pipe 2 was an iron pipe having an outer diameter of 21.7 mm and a wall thickness of 1 mm.

The workability of Examples 1 to 3 and Comparative Example 2 was evaluated based on the workability of Comparative Example 1. Specifically, the workability was evaluated by the feel of a worker who had many years of experience in the work according to Comparative Example 1, and the "OK" and "NG" were judged as follows.
OK: Workability equivalent to that of Comparative Example 1.
NG: Due to the bending of the pipe 2, workability was deteriorated as compared with Comparative Example 1.
The determination result is shown in FIG. As shown in FIG. 3, Examples 1 to 3 were "OK", and Comparative Example 2 was "NG". From these facts, it was confirmed that if the wall thickness of the pipe 2 is at least 1.6 mm or more, the conventional operability can be maintained.

[Second evaluation]
For Examples 1 to 3 and Comparative Example 1 described above, the total amount of heat generated, the first amount of heat, and the second amount of heat were measured and comparatively evaluated. Specifically, the measurement was carried out as follows.
i) An oxygen supply source 4 containing an oxygen-containing gas having an oxygen concentration of 90% was prepared.
ii) When the outer diameter of the pipe 2 is 21.7 mm, the wall thickness of the pipe 2 is 2.8 mm, and the length of the pipe 2 is 4 m, the pipe 2 is introduced into the furnace bottom 9 via the pipe 2. The opening degree of the valve 41 was set so that the flow rate of oxygen was about 65 m ³ / h (Normal), and this opening degree was kept constant in each measurement.
iii) The consumption rate of the pipe 2 was measured, and the second calorific value [kJ / s] was calculated from the measurement result of the consumption rate on the assumption that all the consumed pipes 2 were Fe ₂ O ₃ .
iv) The amount of oxygen used for combustion of the pipe 2 was calculated on the same premise as the above iii).
v) The amount of oxygen supplied through the pipe 2 was measured, and the amount of oxygen used for burning the combustibles in the furnace was calculated by subtracting the calculation result of iv) from the measurement result.
vi) The first calorific value [kJ / s] was calculated from the calculation result of v) above on the assumption that all combustibles in the furnace are CO ₂ .
vi) The total amount of heat generated [kJ / s] was calculated by adding the calculation result of the above iii) and the calculation result of the above vi).
FIG. 4 shows the measurement results of the total amount of heat generated QT, the first amount of heat Q1, and the second amount of heat Q2. As shown in FIG. 4, in Comparative Example 1, the ratio of the second calorific value Q2 to the first calorific value Q1 was about 1 / 2.4. In Examples 1 to 3, the ratios of the second calorific value Q2 to the first calorific value Q1 were about 1 / 2.8, 1 / 3.1, 1 / 3.6, and 1 / 4.5, respectively. In any of Examples 1 to 3, the second calorific value Q2 was the same as in Comparative Example 1. On the other hand, the first calorific value Q1 in Example 1 is larger than that of Comparative Example 1, the first calorific value Q1 in Example 2 is further larger than that of Example 1, and the first calorific value Q1 in Example 3 is in Example 2. It was even bigger than that. From these results, the following findings were obtained.
a) Most of the amount of heat generated by the supply of oxygen through the pipe 2 (hereinafter referred to as "total amount of heat generated") is not the second amount of heat but the first amount of heat.
b) Even if the oxygen supply amount is increased by increasing the inner diameter of the pipe, the second heat amount does not increase.
c) When the amount of oxygen supplied is increased by increasing the inner diameter of the pipe, the amount of first heat increases.
d) In the existing oxygen cleaning device, the ratio of the second calorific value to the first calorific value is about 12.4.
Based on these findings, by adjusting the dimensions of the pipe 2, the ratio of the first heat quantity to the total heat generation amount is increased, the ratio of the second heat quantity to the total heat generation amount is reduced, and the material consumption of the pipe for oxygen cleaning is reduced. It was confirmed that it could be reduced. Furthermore, if the dimensions of the pipe 2 are set so that the ratio of the second calorific value to the first calorific value is less than 1 / 2.4, the material consumption of the pipe 2 can be reduced as compared with the existing oxygen cleaning device. confirmed.

[Third evaluation]
The following 5 types of pipes and 4 types of joint members were prepared.
Pipe 2A: An iron pipe with an outer diameter of 21.7 mm and a wall thickness of 2.8 mm.
Pipe 2B: An iron pipe with an outer diameter of 21.7 mm and a wall thickness of 2.3 mm.
Pipe 2C: An iron pipe with an outer diameter of 21.5 mm and a wall thickness of 2.3 mm.
Pipe 2D: An iron pipe with an outer diameter of 21.7 mm and a wall thickness of 1.9 mm.
Pipe 2E: An iron pipe with an outer diameter of 21.7 mm and a wall thickness of 1.6 mm.
Joint member 21A: An iron pipe (cylindrical member) having an inner diameter of 22 mm and a wall thickness of 2.6 mm.
Joint member 21B: An iron pipe (cylindrical member) having an inner diameter of 22 mm and a wall thickness of 1.7 mm.
Joint member 21C: An iron pipe (cylindrical member) having an inner diameter of 22.2 mm and a wall thickness of 1.6 mm.
Joint member 21D: An iron pipe (cylindrical member) having an inner diameter of 22.5 mm and a wall thickness of 1.6 mm.

Using each of the four types of joint members, pipes of the same type were joined to each of the five types of pipes. After that, "OK" and "NG" were determined for each joint as follows.
OK: No leakage of oxygen-containing gas from the joint.
NG: There is a leak of oxygen-containing gas from the joint.
The determination result is shown in FIG. Of the combinations of the four types of joint members 21 and the five types of pipes 2, those whose evaluation results can be estimated based on the judgment results of the other combinations are appropriately omitted from the evaluation. Of the combinations shown in FIG. 5, the combinations for which the evaluation is omitted are marked with "-" instead of "OK" and "NG".

The results of using the joint member 21A for the pipes 2A, 2B, 2D, and 2E were "OK", "NG", "NG", and "NG", respectively. The reason why the result of using the joint member 21A for the pipes 2B, 2D and 2E was "NG" is that the thickness of the pipes 2B, 2D and 2E is small, so that the pipes 2B, 2D and 2E are deformed after caulking. It is considered that the amount became larger than the deformation amount of the joint member 21A. The result of using the joint member 21B for the pipes 2B, 2D, and 2E was "OK". The result of using the joint member 21C for the pipes 2A, 2B, 2D, and 2E was "OK". The result of using the joint member 21D for the pipes 2B, 2C, 2D, and 2E was "OK". From these results, the following findings were obtained.
e) The value obtained by subtracting the wall thickness of the pipe 2 from the wall thickness of the joint member 21 before caulking is preferably 0.1 mm or less.

If the gap between the pipe 2 and the joint member 21 becomes excessive, it becomes difficult for the pipe 2 and the joint member 21C to come into close contact with each other even after caulking, and there is a possibility that the airtightness at the joint cannot be ensured. In the combination shown in FIG. 5, the difference between the inner diameter of the joint member 21 and the outer diameter of the pipe 2 is the largest in the combination of the joint member 21D and the pipe 2B. The difference between the inner diameter of the joint member 21D and the outer diameter of the pipe 2B was 1 mm, and there was no leakage of oxygen-containing gas in this combination. From this result, it was confirmed that the airtightness at the joint can be ensured if at least the difference between the inner diameter of the joint member 21 and the outer diameter of the pipe 2 is 1 mm or less.

1 ... Oxygen cleaning device, 2, 2A, 2B ... Pipe, 3 ... Pipe holder, 21 ... Joint member.

Claims (5)

Equipped with a pipe for introducing a gas containing oxygen into the melting furnace,
The ratio of the second calorific value generated by burning the pipe itself by the oxygen supply through the pipe to the first calorific value generated by burning the combustibles in the melting furnace by oxygen supply through the pipe is 1 /. The outer diameter and wall thickness of the pipe are set so that it is less than 2.4 .
An oxygen cleaning device for a melting furnace , wherein the outer diameter of the pipe is 20.7 to 21.7 mm, and the wall thickness of the pipe is 1.6 to 2.3 mm . The outer diameter of the pipe is determined to fit with the pipe holder that holds the pipe.
The oxygen cleaning apparatus for a melting furnace according to claim 1, wherein the wall thickness of the pipe is set so that the ratio of the second calorific value to the first calorific value is less than 1 / 2.4. The oxygen cleaning device for a melting furnace according to claim 1 or 2, wherein the outer diameter and the wall thickness of the pipe are set so that the inner diameter of the pipe is larger than 16.1 mm. The oxygen cleaning according to any one of claims 1 to 3 , wherein the outer diameter and the wall thickness of the pipe are set so that the flow rate of the gas passing through the pipe is larger than 65 m ³ / h (Normal). apparatus. Further provided with a tubular joint member mounted on the outer circumference of the pipe and joining the pipes to each other by caulking.
The oxygen cleaning device according to any one of claims 1 to 4 , wherein the value obtained by subtracting the wall thickness of the pipe from the wall thickness of the joint member before caulking is 0.1 mm or less.

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