JP4846512B2 - Carbon adhesion control method for coke oven carbonization chamber - Google Patents

Description

  The present invention relates to a method for suppressing the adhesion of carbon generated in an upper space (hereinafter referred to as a furnace top space) of a coke oven carbonization chamber.

  When carbonizing coal in a coke oven, pulverized coal generated from coal dust or hydrocarbon-based gas generated from coal (hereinafter referred to as coal) Precipitated carbon (hereinafter referred to as adherent carbon) derived from the thermal decomposition of the gas) is generated. When the amount of adhering carbon is excessive, the resistance when extruding coke is increased, and problems such as a decrease in the volume of the carbonization chamber and blockage of the riser base portion occur. Specifically, if the amount of carbon adhering to the top space of the furnace increases, the resistance when extruding coke at the end of dry distillation increases, and in the worst case, the coke extrusion operation stops halfway. The possibility increases. In addition, coal gas is sent from the furnace top space to the post-treatment process through the riser pipe. However, if the passage cross-sectional area of the furnace top space decreases, the ventilation resistance increases. Since it leaks in, it is not preferable. Furthermore, if the ascending pipe is blocked, the carbonized product gas cannot be sent to the post-treatment process, which causes a very important problem in operation.

  It is widely known that the rate of carbon deposition is largely dependent on temperature, the volatile content and moisture of the charged coal, and the higher the temperature, the higher the volatile content, the lower the moisture, The amount of attached carbon generated in the process increases. Therefore, in order to suppress the production amount of adhering carbon, 1) keep the temperature of the furnace top space, the riser base, and the inner wall of the riser low, 2) lower the volatile content of the charged coal, 3) Increasing the moisture content of the charged coal is an effective measure.

  Of these, lowering the volatile content of the charged coal in 2) reduces the amount of coal gas that is a source of attached carbon, and can be said to be an effective means for suppressing attached carbon. However, in Japan, where energy costs are high, coal gas is not only an important energy source for steelworks, but also a raw material for chemical products such as tar, and as an important by-product after coke. It is positioned. Therefore, it is difficult to implement a method for reducing the volatile content of the charged coal as a countermeasure for suppressing the attached carbon.

  Further, it is known that increasing the water content of the charged coal in the above 3) has an effect of diluting the coal gas, and thus is effective in suppressing adhering carbon. However, increasing the water content of the charged coal causes a decrease in charging density and uneven carbonization, which not only reduces the productivity and quality of coke, but also increases the energy consumption of dry distillation. It is not preferable because it causes a disadvantage.

  Therefore, in order to suppress the amount of attached carbon in the furnace top space, most studies have been made on the method of controlling the temperature of 1).

  In order to keep the temperature of the top space, riser base, and riser inner wall surface in 1) low, it is effective to lower the operating temperature (hereinafter, furnace temperature) of the coke oven. However, if the furnace temperature is lowered, the carbonization time becomes longer, leading to a reduction in coke production. Therefore, although an effect can be expected as a method for reducing the amount of attached carbon, it must be determined that it is a difficult means to implement under conditions of high production operation.

  In view of this, a method has been proposed in which the temperature of the top space of the furnace, the riser base, and the inner wall of the riser can be controlled independently of the furnace temperature even under high production operation. This method is roughly classified into a method of directly introducing a cooling medium into the furnace top space portion and a method of laying a pipe inside the ceiling brick and flowing a refrigerant to indirectly lower the temperature.

As an example of the former method, as proposed in Japanese Patent No. 3284032, a method of spraying water into the furnace top space during coal carbonization, or as proposed in Japanese Patent Application Laid-Open No. 03-210389, A method of injecting coal gas from a gas injection pipe provided adjacent to the charging inlet of the exhaust gas, or as proposed in Japanese Patent Laid-Open No. 03-212486, a part of combustion exhaust gas is injected, and CO ₂ and H in the exhaust gas are injected. _The atmospheric temperature is lowered by an endothermic reaction in which CO is generated by the reaction between ₂ O and adhering carbon.

  On the other hand, as an example of the latter method, as proposed in Japanese Patent No. 0975687 and Japanese Patent Laid-Open No. 10-1676, vent holes are provided in the ceiling brick of the carbonization chamber, and fluid is circulated from the cooling gas introduction pipe. And cooling the ceiling brick of the carbonization chamber to cool the furnace top space.

  All of the above-described methods for suppressing the amount of attached carbon are effective in principle, but in order to achieve the purpose, piping for supplying a cooling fluid is installed in the carbonization chamber. There is a need to. In particular, the method of cooling by providing ventilation holes in the ceiling bricks, in addition to the pipe laying work, causes construction costs such as crushing and cutting of the bricks, except when applied to a small number of carbonization chambers. There is a problem that the amount of investment becomes excessive.

  Therefore, there is a need for a method for suppressing the formation of attached carbon without using such means that requires piping.

  In view of the above problems, the present invention, without adjusting the operating conditions of the coke oven and the properties of the coal (volatile matter, moisture), immediately after charging the coal into the furnace top space, the riser base and the riser inner wall, and A method for suppressing the amount of attached carbon produced during coal carbonization is provided.

  As a result of various studies to solve the above problems, the present inventors place a structure having a hollow structure on the surface layer of the charge immediately after charging coal into the carbonization chamber. Thus, it has been found that the formation of attached carbon can be suppressed, and the present invention has been completed based on this finding.

That is, the gist of the present invention is as follows.
(1) The surface of the coal packed bed charged in the carbonization chamber of the coke oven is made of a material that carbonizes during coal carbonization, and has a gas flow passage formed of a cavity penetrating in the furnace length direction inside, and A carbon flow control in a coke oven carbonization chamber characterized in that a flow straightening box having a gas inlet comprising an opening is placed on the bottom surface, and carbon adhering to the coal produced during coal carbonization is captured in the flow straightening box. Method.
(2) In the cavity of the rectifying box, a partition wall is provided along the furnace length direction to partition the cavity and prevent deformation of the ceiling plate and the bottom plate (1) The carbon adhesion suppression method of the coke oven carbonization chamber as described in 1).
(3) The above (1) or characterized in that a plurality of partition plates are provided on the surface of the ceiling plate in the rectifying box along the furnace width direction in order to generate a gas circulation flow in the upper part of the cavity. The method for suppressing carbon adhesion in a coke oven carbonization chamber according to (2).
(4) The rectifying box is inserted immediately after charging coal into the coke oven carbonization chamber, or from a charging inlet provided in the upper portion of the carbonization chamber or a leveling lid provided in the upper portion of the furnace lid. The method for suppressing carbon adhesion in a coke oven carbonization chamber according to any one of (1) to (3) above.

  According to the present invention, when the coal is carbonized in the coke oven, the surface of the coal packed bed in the coke oven carbonization chamber has a cavity penetrating in the furnace length direction inside, and a rectifying box having an opening on the bottom surface. The amount of adhering carbon generated in the furnace top space in the carbonization chamber can be significantly reduced by placing and preferentially capturing the adhering carbon derived from pyrolysis or pulverized coal. Thereby, the extrusion load of coke is reduced, and effects such as an increase in the amount of wreckage and prevention of furnace damage can be obtained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
As shown in FIG. 1, the present invention is characterized by a rectifying box 1 having a cavity 4 that forms a gas flow passage penetrating in the furnace length direction and an opening 5 that forms a gas inlet in a bottom plate 3. Is placed on the surface of the coal packed bed charged in the carbonization chamber of the coke oven. Coal gas 6 generated during the carbonization of coal enters the cavity 4 through the opening 5 provided in the bottom plate 3 of the box, and is discharged from the open end 7 as a horizontal flow in the furnace length direction. . The rectifying box 1 is placed in a high-temperature space of 850 ° C. or higher in the carbonization chamber, and the attached carbon generated from coal during coal dry distillation, that is, the attached carbon derived from pulverized coal or pyrolysis generated from coal gas, As a result of being trapped inside, the amount of attached carbon generated on the furnace wall surface of the carbonization chamber is reduced.

  It should be noted that a plurality of openings 5 provided in the bottom plate 3 are preferably provided in the furnace length direction, and the shape of the openings 5 is a circle in FIG. Needless to say, the shape is not particularly limited to a circle as long as it allows coal gas to pass through, and may be square or triangular.

In addition, the material of the rectification box must satisfy all the following functions in consideration of use in a commercial coke oven.
(1) The original shape must be maintained for at least one cycle of dry distillation without melting or disappearing at a high temperature of 700 ° C. or higher.
(2) When extruding coke, it should be easily destroyed and the furnace wall should not be damaged.
(3) It is lightweight and can be handled by human power, or it must not enter the packed bed when placed on the coal surface.
(4) Do not damage other production equipment in the process of transporting coke after it is discharged from the coke oven.

  As a material of the rectifying box having the above functions, a material that carbonizes during coal carbonization, such as paper and wood, is optimal.

  When a rectifying box made of a material that carbonizes during coal carbonization, such as paper or wood, is charged into the carbonization chamber of a coke oven, it does not melt even in an oxygen-free and high-temperature atmosphere, It is possible to carbonize and maintain the function of welding the attached carbon while the flow straightening box remains almost intact.

  Further, if the flow straightening box is carbonized before the end of coal carbonization, the flow straightened during the coke extrusion after dry distillation collapses relatively easily even if it comes into contact with the furnace wall, so that the furnace wall is not damaged. As described above, the temperature in the carbonization chamber is set to 850 ° C. or higher. However, if a material that carbonizes at 700 ° C. or higher, which is a lower temperature than the carbonization chamber, is selected for the rectification box, the effect of the present invention can be obtained sufficiently. The present inventors have confirmed that it is obtained by actually conducting tests.

  In addition, the material that carbonizes during coal carbonization, such as paper and wood, has a relatively low density and is light in weight, making it easy to handle manually when inserting a rectification box into a coke oven carbonization chamber, After being placed on the surface, it does not sink into the coal packed bed.

  Furthermore, the coke discharged from the carbonization chamber is discharged to the wharf or dry fire extinguishing bucket through the guide grid. At this time, the carbonized rectification box is easily broken into small pieces by the drop impact at that time. Therefore, there is no risk of damaging other production equipment while being transported to the blast furnace through the fire extinguishing process. Further, since the carbonization chamber of the coke oven is usually an oxygen-free atmosphere, it does not burn out due to combustion.

  A polymer material such as plastic satisfies the above condition (3) in that the structure can be reduced in weight. However, since the heat resistance is not sufficient, the polymer material melts at a high temperature of less than 700 ° C. immediately after entering the carbonization chamber. Or it gasifies and does not satisfy the condition (1). Further, although the condition (1) is satisfied with a metal, the furnace wall is highly likely to be damaged during extrusion, and the conditions (2) and (3) are not satisfied.

  Further, another feature of the present invention is that a partition wall 8 is installed along the furnace length direction in the cavity 4 of the rectifying box as shown in FIG. This partition wall reaches from the ceiling plate 2 of the box to the bottom plate 3, prevents the ceiling plate 2 and the bottom plate 3 of the box from being deformed, and maintains the original shape of the box. It serves to capture the attached carbon more efficiently by partitioning the cavity and increasing the internal surface area.

  Further, as shown in FIG. 2, a further feature of the present invention is that a plurality of separation plates 9 are installed on the surface of the ceiling plate 2 of the rectifying box 1 along the furnace width direction. The role of the partition plate is to prevent deformation in the direction perpendicular to the side surface of the rectifying box 1 and the partition wall 8 and to create a circulation flow 11 of coal gas in the space 10 defined by the partition plate at the top of the cavity. This is to increase the residence time of the coal gas in the interior and increase the production efficiency of adhering carbon in the rectifying box 1, thereby improving the capture efficiency.

  The separation plate 9 is attached to the ceiling plate 2 in a suspended state. This is because the coal gas that has entered the box flows along the ceiling surface, and if there is a gap, the circulation flow 11 is difficult to form. It is. On the contrary, needless to say, it is necessary to leave a gap between the dividing plate 9 and the bottom plate 3.

  Next, the form at the time of installing the rectification box used by this invention in the inside of a carbonization chamber is demonstrated. As described above, the coal gas enters the cavity 4 through the opening 5 at the bottom of the rectifying box, so that it is most suitable to install it on the surface layer of the carbonization chamber of the coke oven. In addition, it may be embedded in the packed bed, but in that case, coal gas generated from the coal above the installed height cannot enter the rectification box, so the effect of the present invention is reduced. End up.

  Next, a method for placing the rectifying box on the surface layer of the packed bed will be described with reference to FIG. As described above, considering that the effect of the rectification box is exerted by the coal gas passing through the rectification box, the coal is charged into the carbonization chamber of the coke oven and the surface is smoothed (equalization). It is desirable to place it immediately after finishing the work. Even if the coal 18 is placed after a while, the effect of reducing adhering carbon by the rectifying box can be obtained. However, the longer the time until placing the coal 18 is, the more adhering from coal gas generated during that time. Since carbon is generated in the furnace top space 17, the effect of the rectifying box is reduced accordingly.

  Moreover, the flow straightening box is put into the carbonization chamber after the coal is charged from the charging port 13 installed at the upper part of the carbonization chamber or from the leveling cover 16 usually installed at the upper part of the furnace lid on the extruder side. And In addition, a dedicated opening for inserting the rectification box into the furnace may be provided.

  The present invention was applied to a room type coke oven that is performing commercial production, and a test for confirming the adhesion carbon suppression effect was conducted. The size of the carbonization chamber in which the test was performed is: furnace width (average): 0.4 m, carbonization chamber height: 5 m, effective furnace length: 14 m, and number of inlets: 5.

First, as shown in Table 1, a test was performed in which the number of rectification boxes placed in the furnace was changed. The rectifying box used was manufactured by processing corrugated cardboard having a five-layer structure (thickness 8 mm), and the size of one piece was set to width: 300 mm, height: 100 mm, and length: 1500 mm.

  The shape of the rectification box is as shown in FIG. That is, the number of the partition walls 8 inside the box was two. The opening 5 was a circle of 60 mmφ. The height of the separation plate 9 (length from the ceiling surface) was 40 mm so that a substantially equal space was formed in the lower part. The number of separation plates provided in the furnace length direction was 15.

  The rectification box is inserted into the carbonization chamber after the coal charging into the carbonization chamber is completed and the charging vehicle is withdrawn, and the charging lids 13 (a to e) at predetermined positions shown in FIG. 3 are removed. The rectification box 15 (a to e) was inserted manually and placed on the surface of the coal 18.

  In order to confirm the effect of the present invention, as shown in FIG. 3, a test piece 12 (material: quartz brick, size: 30 × 30 × 60 mm) is suspended from the inlet 13e closest to the riser 14, and one cycle of dry distillation is performed. The amount of attached carbon was measured. Moreover, the thermometer 19 was installed in the same position as the test piece, and the temperature of the furnace top space 17 was measured.

  The test results obtained are shown in FIG. In this figure, the vertical axis represents the amount of carbon deposited on the test piece during one dry distillation, and the smaller this value, the greater the effect of reducing the amount of attached carbon of the present invention. From FIG. 4, by placing the flow straightening box on the surface of the coal packed bed charged in the carbonization chamber, the amount of attached carbon generated on the test piece decreases, and as the number of loaded carbons increases, It can be seen that the effect is increasing.

  Next, when the number of rectifying boxes was set to five as in level 6 in Table 1, a test was performed in which the number of separation plates 9 in the rectifying box was changed. The results of the test are shown in FIG. 5, and it can be seen that the greater the number of fraction plates, the greater the effect of suppressing adhering carbon.

  Furthermore, when the number of rectifying boxes is set to 5 as in level 6 in Table 1 and the number of separation plates in each rectifying box is 15, various timings for mounting the rectifying boxes in the furnace top space are various. The test which changes to is carried out. However, the results of the test are shown in FIG. 6, and the rectifying box has the greatest effect when placed in the furnace top space for the entire period of carbonization from immediately after coal charging to 8 hours when carbonization ends. You can see that It can be seen that the effect of reducing attached carbon can be obtained even when placed in the middle of dry distillation, but the effect of the present invention is reduced as the placement timing is delayed.

In each implementation level, the temperatures of the upper space 17 of the carbonization chamber are all different. Since it is widely known that the amount of attached carbon depends on the temperature, if the amount of attached carbon of the test piece 12 is compared as it is, the evaluation is not correct. Therefore, using the average value of the temperature of the upper space at each implementation level (the temperature described in the graphs of FIGS. 4, 5, and 6), ).

Exp (-7950 / T _O )
W _M = W _O × ---------------------------------- ----- 1)
Exp (-7950) / T _ave )

W _O : Actually measured weight of attached carbon (kg)
W _M : Weight of adhering carbon corrected for temperature (kg)
T _ave : Average value of space temperature (K)
T _O : Actual temperature (K) in each measurement

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention and is a diagram illustrating an outline of a structure of a rectification box. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1, illustrating an embodiment of the present invention, is a diagram illustrating an outline of a composition of a separation plate inside a rectifying box. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating an embodiment of the present invention and is a diagram illustrating a mounting state of a rectification box in an actual top space of a coke oven. FIG. 5 is a diagram illustrating the effect of the embodiment of the present invention, and is a diagram illustrating the relationship between the number of rectifying boxes placed on the packed bed of the carbonization chamber and the amount of attached carbon. FIG. 5 is a diagram illustrating the effect of the embodiment of the present invention, and is a diagram comparing the adhesion carbon suppression effect depending on the number of separation plates of the rectifying box. FIG. 6 is a diagram for explaining the effect of the embodiment of the present invention, and is a diagram comparing the amount of carbon adhering depending on the timing when the rectification box is placed in the top space of an actual coke oven.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rectification box 2 ... Ceiling board 3 ... Bottom board 4 ... Cavity 5 ... Opening part 6 ... Coal gas
7 ... Open end 8 ... Partition wall 9 ... Fractionation plate 10 ... Space 11 defined by the separation plate 11 ... Circulating flow 12 ... Test piece
13a to 13e ... charging port 14 ... ascending pipes 15a to 20e ... rectification box 16 ... leveling lid 17 ... upper space 18 ... coal 19 ... thermometer

Claims (4)

  The surface of the coal packed bed charged in the coking chamber of the coke oven is made of a material that carbonizes during coal carbonization, and has a gas flow passage formed of a cavity that penetrates in the length direction of the furnace, and is open at the bottom. A method for suppressing carbon adhesion in a coke oven carbonization chamber, wherein a rectifying box having a gas inlet composed of a portion is placed and trapped carbon generated from coal during coal dry distillation is captured in the rectifying box.   2. The partition wall according to claim 1, wherein a partition wall is provided in the cavity of the flow straightening box to partition the cavity and prevent a deformation of the ceiling plate and the bottom plate along the furnace length direction. A method for suppressing carbon adhesion in a coke oven carbonization chamber.   3. The partition plate according to claim 1, wherein a plurality of partition plates are provided on a surface of the ceiling plate in the rectification box along a furnace width direction in order to generate a circulating flow of gas in the upper portion of the cavity. A method for suppressing carbon adhesion in a coke oven carbonization chamber.   The rectifying box is inserted immediately after charging coal into a coke oven carbonization chamber, or from a charging port provided in the upper portion of the carbonization chamber or a leveling lid provided in the upper portion of the furnace lid. The carbon adhesion suppression method of the coke oven carbonization chamber in any one of 1-3.

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