JP2013199560A - Method for reconstructing coke oven and reconstructed coke oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dismantle a coke oven and reconstruct a coke oven more improved in productivity compared to that before dismantlement.SOLUTION: A reconstruction method of a chamber type coke oven, in which a regenerative chamber is disposed on a hearth structure, and a carbonization chamber and a combustion chamber are alternately disposed thereon, comprises: (x) dismantling the carbonization chamber, combustion chamber and regenerative chamber, while leaving the hearth structure; (y) constructing a regenerative chamber with height lower than that before dismantlement on the hearth structure; and (z) constructing a carbonization chamber and a combustion chamber on the regenerative chamber by (z1) increasing the height by the decreased height of regenerative chamber.

Description

  The present invention relates to a method of dismantling an aging coke oven and reconstructing a coke oven with high productivity, and a coke oven constructed by the method.

  Usually, in a coke oven, a heat storage chamber is constructed on a hearth structure, and a carbonization chamber and a combustion chamber constructed with refractory bricks are alternately arranged thereon. The refractory bricks that make up the carbonization chamber and the combustion chamber are worn out by the operation of the coke oven. In particular, the wear of the furnace wall that separates the carbonization chamber and the combustion chamber causes troubles during coke extrusion, so the extent of wear of the furnace wall is monitored, and an amorphous refractory is sprayed on the markedly worn part. Repair.

  If the wall of the furnace wall is severely worn, a broken hole in which a part of the furnace wall falls off during coke extrusion may occur. When a hole breaks in the furnace wall, it is necessary to repair the broken hole part by stacking refractory bricks on the broken hole part.

  In any case, since the required number of days is required for repairing the furnace wall, the operation must be stopped during that time, so the productivity of the coke oven decreases. Furthermore, if the frequency of furnace wall repair is increased, productivity is extremely reduced. Thus, several methods for repairing the coke oven have been proposed (see Patent Documents 1 to 3).

  The proposed repair method can extend the life of the furnace, but in recent years, in addition to long-term operation, the operating conditions have become harsher to improve productivity, and the aging of the coke oven has accelerated. The frequency of wall repairs is increasing. Therefore, in a coke oven operating for a long time, there is a limit to the extension of the furnace life by furnace wall repair, and the productivity is extremely reduced due to the increase in the frequency of furnace wall repair.

JP 2000-002491 A JP 2001-019968 A JP 2004-231681 A

  The present invention is based on the premise of disassembling and reconstructing the coke oven in view of the current state of the coke oven operating for a long time, and not simply constructing the same coke oven as before demolition, An object is to construct a coke oven that is more improved than before dismantling, and an object is to provide a method for reconstructing a coke oven that solves the problem, and a coke oven constructed by the method.

  The inventors of the present invention have intensively studied a method for solving the above-described problems.

  As a result, when reconstructing the coke oven on the hearth structure that holds the coke oven, (a) the height of the heat storage chamber is reduced, and (b) the reduction, the carbonization chamber and the combustion chamber furnace If the height is increased, the coke oven volume can be increased while maintaining the same total furnace height (furnace height including the heat storage chamber height) as before dismantling. It turned out that the existing ancillary equipment can be used as it is.

  This invention was made | formed based on the said knowledge, and the summary is as follows.

(1) In a restructuring method of a chamber type coke oven in which a heat storage chamber is arranged on the hearth structure, and a carbonization chamber and a combustion chamber are alternately arranged thereon,
(X) dismantling the carbonization chamber, combustion chamber, and heat storage chamber, leaving the hearth structure;
(Y) On the hearth structure, a heat storage chamber is constructed with a reduced height before dismantling,
(Z) A coke oven restructuring method characterized in that a carbonization chamber and a combustion chamber are built on the heat storage chamber to be higher by a reduction in the height of the heat storage chamber.

  (2) The method for reconstructing a coke oven according to (1), wherein the furnace core pitch (the width of the carbonization chamber + the width of the combustion chamber) is set larger than the furnace core pitch before dismantling.

  (3) A reconstructed coke oven characterized by being reconstructed by the method for reconstructing a coke oven as described in (1) or (2) above.

  According to the present invention, since the volume of the carbonization chamber is increased as compared with that before dismantling, a coke oven with high productivity can be provided. Further, according to the present invention, since the total furnace height of the coke oven is the same as that before the dismantling, the existing incidental equipment arranged in the upper part of the furnace can be used as it is.

It is a figure which shows the basic structure of a chamber type coke oven. (A) shows the cross-sectional structure in the furnace length direction, and (b) shows a part of the cross-sectional structure in the furnace width direction. It is a figure which shows the meaning of the symbol used by the formula (Formula (1)) of Suga and Shimokawa. It is a figure which shows typically the structure of the slot brick placed in a thermal storage chamber. (A) shows the conventional slot brick structure, (b) shows the highly efficient slot brick structure used for reconstruction.

(First invention)
The present invention is a method for reconstructing a coke oven in which a heat storage chamber is arranged on the hearth structure, and a carbonization chamber and a combustion chamber are alternately arranged thereon,
(X) dismantling the carbonization chamber, combustion chamber, and heat storage chamber, leaving the hearth structure;
(Y) On the hearth structure, a heat storage chamber is constructed with a reduced height before dismantling,
(Z) A charcoal chamber and a combustion chamber are constructed on the heat storage chamber, and (z1) height is constructed by increasing the height of the heat storage chamber.

  The first invention will be described below with reference to the drawings.

  First, FIG. 1 shows the basic structure of a chamber coke oven. FIG. 1A shows a sectional structure in the furnace length direction, and FIG. 1B shows a part of the sectional structure in the furnace width direction. In the coke oven, the heat storage chamber 2 is disposed on the hearth support structure 1, and the combustion chamber 3 and the carbonization chamber 4 are alternately disposed thereon (see FIG. 1B). The combustion chamber 3 and the carbonization chamber 4 are covered with a ceiling wall 5. Fuel gas is fed into the heat storage chamber 2 from the fuel gas supply path 7 and air is fed from the air supply path 8. Air and fuel gas are preheated and then burned in the combustion chamber. The combustion exhaust gas passes through the heat storage chamber, exchanges heat with the heat storage bricks, and then is discharged from the chimney through the flue 6.

  Next, the coke oven rebuilding method of the present invention (hereinafter sometimes referred to as “the method of the present invention”) will be specifically described with reference to the dimensions of the respective parts shown in FIG.

  The method of the present invention is intended for a room type coke oven that has been operating over a long period of time and has deteriorated and the productivity has decreased. In the implementation of the reconstruction, first, the brick structure (the heat storage chamber and the combustion chamber and the carbonization chamber) on the hearth support structure (see FIG. 1) is disassembled, and then the hearth support structure of the hearth support structure is disassembled. A new heat storage chamber, carbonization chamber and combustion chamber will be built on top.

At this time, the total furnace height H (= the height Hb ₁ of the combustion chamber or the carbonization chamber + the height Ha _{1 of the} heat storage chamber + the height Hd _{1 of the} furnace top deck) remains constant, and the height Ha ₂ of the heat storage chamber is set to be constant. The heat storage chamber is constructed by reducing ΔHa (= Ha ₂ −Ha ₁ ) lower than the height Ha ₁ of the heat storage chamber before dismantling.

  Note that the subscript 1 means before dismantling, and the subscript 2 means after reconstruction. The same applies hereinafter.

  The height of the carbonization chamber (ΔHc) and the increase of the furnace top deck (ΔHd) are performed by the reduction in the height of the heat storage chamber (ΔHa). It is a feature of the present invention that the dimensions of ΔHc, ΔHa, and ΔHd satisfy ΔHa = ΔHc + ΔHd and are constructed without changing the total furnace height.

(Method for determining the height (Ha) of the heat storage chamber)
The heat storage chamber is installed for exchanging heat between the combustion exhaust gas and the fuel gas and effectively using the sensible heat of the exhaust gas, and a large number of slot bricks are arranged in the heat storage chamber. The heat exchange performance of the heat storage chamber is determined mainly depending on the heat transfer area of the slot brick and the velocity of the gas passing through. Therefore, in order to make the height of the heat storage chamber lower than before the dismantling, the heat exchange efficiency is improved by using a highly efficient firebrick.

  FIG. 3 schematically shows the structure of the slot brick placed in the heat storage chamber. FIG. 3A shows a conventional slot brick structure, and FIG. 3B shows a high-efficiency slot brick structure used for reconstruction. As shown in FIG.3 (b), the slot number of a single slot brick is increased and the highly efficient slot brick which increased the heat-transfer area is used.

By using the high-efficiency slot bricks, it is possible to obtain the same heat exchange performance as before the dismantling even if the heat storage chamber is lower than before the dismantling. For example, by using a highly efficient brick with a heat transfer area of 1.5 times, the heat storage chamber height Ha ₁ before dismantling was 2.4 m, but after reconstruction, Ha ₂ was changed to 1. Can be 9m.

(Method for determining the height (Hc) and deck height (Hd) of the carbonization chamber)
When the furnace height is increased, the expansion pressure of the coal charged into the carbonization chamber and the side pressure during coke extrusion increase, resulting in insufficient furnace wall strength. Necessary furnace wall strength is secured by increasing the furnace top deck thickness (Hd, B). In the case of expanding the height of the coke oven in the coke oven to be reconstructed, it is economical to improve the furnace wall strength by the thickness of the top deck.

  The thickness of the top deck of the coke oven to be reconstructed is the furnace wall strength K calculated by the Suga and Shimokawa equation (the following equation (1)) (Coke Circular, 20 (1971), No. 2, p. 111.). It is necessary to determine the value to be 10 kPa or more (see Y. Suga, E. Shimokawa: Ironmaking Proceedings, AIME, vol. 29, 1970, p. 9).

K = 2 (M _T ^1/2 + M _B ^1/2 ) ² / (EI ² ) (1)
Where M _T = EABDS _D
M _B = D [EABDS _D + EDCDS _L + 2G (I−C) ES _L
+ (D-2G) F (I-H-C) S _L ]]
Where S _D : furnace deck ratio
S _L : Furnace wall specific gravity The letters in the formula (1) mean the length of the portion shown in FIG.

Usually, since the volume of the carbonization chamber is maximized, the minimum reference value itself (10 kPa) is adopted as the K value in the Suga and Shimokawa equation. At this time, each of the furnace height (Hc) and the height of the furnace top deck (Hd) is uniquely determined. According to these numerical values, by increasing the height Hb ₂ of the combustion chamber and the coking chamber, to construct a carbonization chamber and the combustion chamber.

That is, in the reconstructed coke oven, the height of the combustion chamber 3 and the carbonization chamber 4 (Hc ₂ )> combustion before disassembly under the same total furnace height H as before disassembly and the same furnace core pitch as before disassembly. It is the height (Hc ₁ ) of the chamber and the carbonization chamber. This is a feature of the method of the present invention.

  Since the total furnace height H of the reconstructed coke oven is the same as that before the dismantling, the existing incidental equipment arranged at the upper part of the coke oven can be used as it is.

(Second invention)
In the reconstructed coke oven, the furnace temperature is raised compared to the coke oven before dismantling, and in addition to the first invention, the furnace core pitch W ₂ (the width Wc _{2 of the} carbonization chamber + the width of the combustion chamber) It is preferable to construct Wb ₂ ) larger than the kiln core pitch W ₁ before dismantling. As a result, in addition to increasing the furnace height, the width of the carbonization chamber can also be increased, and the productivity can be further improved.

  Here, even when the width Wc of the carbonization chamber is expanded, the furnace wall strength is lowered, so that it is necessary to improve the furnace wall strength. When expanding both the furnace height and the width of the coking chamber in the dimensions of the carbonizing chamber of the coke oven to be reconstructed, it is more economical to improve the furnace wall strength by increasing the kiln core pitch.

  Moreover, in the reconstructed coke oven, when the width of the carbonization chamber is expanded, there is a concern that a shortage of dry distillation may occur in the center of the carbonization chamber, causing troubles during coke extrusion. The expansion of the width of the carbonization chamber decreases the heat transfer rate to the center of the carbonization chamber and extends the carbonization time.

  On the other hand, by increasing the amount of fuel gas and air to the combustion chamber and making the combustion chamber temperature higher than the conventional combustion chamber temperature, it is possible to secure the same dry distillation time in the rebuilt coke oven as before dismantling. Become.

At this maximum temperature, the width Wc _{2 of the} carbonization chamber that can ensure a dry distillation time equivalent to that before dismantling is set. Adopting high-efficiency slot bricks for the Wc ₂ and the heat storage chamber, the furnace core pitch is expanded for the expanded furnace height Hb ₂ to ensure the furnace wall strength. Similar to the first invention, the required furnace wall strength is calculated by the Suga and Shimokawa equation, and the furnace wall strength K value needs to be 10 kPa or more.

If the furnace wall strength K value is set to 10 kPa based on the Suga and Shimokawa equation based on Wc ₂ and Hb ₂ derived from the maximum furnace temperature, the kiln core pitch W ₂ is uniquely determined.

Thereby, the height (furnace height) Hb ₂ of the combustion chamber and the carbonization chamber is increased (as a result, the total furnace height H of the coke oven is the same), and the kiln core pitch W ₂ (= the width of the carbonization chamber 4). Wc ₂ + width Wb _{2 of} combustion chamber 3 is made larger than kiln core pitch W ₁ before disassembly (= width Wc ₁ of carbonization chamber 4 + width Wb ₁ of combustion chamber 3) to construct a combustion chamber and a carbonization chamber. To do.

  Further, as described above, in order to increase the combustion gas temperature by increasing the amount of fuel gas and air, it is necessary not only to satisfy the physical properties of the furnace wall brick but also to satisfy constraints such as environmental load.

  Usually, there is a NOx regulation value based on the Air Pollution Control Law before the reconstruction, so low NOx combustion technology, for example, exhaust gas circulation or low NOx is used to satisfy these standards even if the combustion amount is increased during the reconstruction. Adopt a burner to deal with it.

  Next, examples of the present invention will be described. The conditions of the examples are one example of conditions adopted for confirming the feasibility and effects of the present invention, and the present invention is limited to this one example of conditions. Is not to be done. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.

(Example)
A coke oven with a total furnace height of approximately 12 m, a furnace height of 5.5 m, and a furnace core pitch of 1300 mm (carbonization chamber width 450 mm, combustion chamber width 850 mm), which has been in operation for 40 years, was dismantled. A coke oven of 0.0 m, kiln core pitch 1380 mm (carbonization chamber width 470 mm, combustion chamber width 910 mm) was reconstructed.

  The heat storage chamber is made of high-efficiency slot brick (see Fig. 3 (b)), which has a heat transfer area 1.5 times that of the conventional one, so that the height of the heat storage chamber is increased from 2.4m to 1.m. The furnace height could be reduced by 0.5 m to 9 m, and the furnace height was increased by 0.5 m. The specifications of the newly built coke oven were determined according to the following.

  The heat storage chamber of the coke oven before dismantling is 2.4 m high, and 16 mm slot bricks are arranged in the heat storage chamber for both the web slot. On the other hand, when a high-efficiency slot brick with a web slot of 11 mm (heat transfer area 1.5 times) is adopted, the required heat storage chamber height is calculated as 1.9 m from the heat exchange calculation. . Therefore, the furnace height could be increased from 5.5 m to 6.0 m.

  On the other hand, the coke oven before dismantling had a kiln core pitch of 1300 mm, a carbonization chamber width of 450 mm (combustion chamber width of 850 mm), and was operated at a combustion chamber temperature of 1200 ° C. The carbonization time at this time was 18.4 hours. In the current technology, operation at a combustion chamber temperature of 1270 ° C. is possible due to restrictions such as physical properties of furnace wall bricks and environmental loads.

  The reason why the carbonization time is about 18.4 hours at the combustion chamber temperature of 1270 ° C. is that the width (temporary value) of the carbonization chamber is calculated to be 510 mm from the calculation by the heat transfer model.

  When the furnace height is increased by 0.5 m and the width of the carbonization chamber is increased by 60 mm, the furnace wall strength K value decreases by about 20%. To make this furnace wall strength the same as before dismantling, It is necessary to increase the core pitch to 1430 mm. At this time, the number of kilns that can be installed is 82 with respect to 90 coke ovens before dismantling.

  If the number of installed gates decreases and the carbonization time is the same as that of the coke oven before dismantling, the capacity will be insufficient when the existing incidental equipment is diverted. The moving machine, which is one of the diverted equipment installed in the coke oven before demolition, has a capacity of 124 extrusions / day.

  When the number of newly built coke ovens is reduced, the same efficiency can be maximized by using the same 124 k / day extrusion as the coke oven before demolition to maximize productivity. In order to secure the number of extrusions, it is necessary to shorten the carbonization time corresponding to the reduction in the number of installation gates. In order to shorten the carbonization time, it is necessary to make the width of the carbonization chamber narrower than the temporary value 510 mm obtained from the heat transfer calculation.

  From the above, the width of the coking chamber calculated from the maximum furnace temperature is narrowed to shorten the carbonization time, the number of extrusions is 124 per day, and the width of the coking chamber satisfying the furnace height of 6.0 m, the kiln core pitch, and The number of installed gates and the carbonization time are 470 mm in width of the carbonization chamber, 1380 mm in kiln core pitch, 16.4 hours in the carbonization time, and 84 gates installed. This combination of carbonization chamber and furnace core pitch provides the best production efficiency.

  As a result, since the total furnace height and the number of extrusions of the coke oven were the same, the existing incidental facilities could be used, and the operation could be started immediately after the reconstruction.

  Furthermore, in the reconstructed coke oven, the number of coke extrusions decreases from 124 times / day to 109 times / day, so that it is expected to reduce the environmental load such as dust generation. In addition, since the operating rate of the coke oven decreases, it can be expected to extend the life of the coke oven.

  This technique can be applied according to the properties of the coal to be charged in the coke oven and the conditions of the coal to be charged, and can be applied in any case.

  As described above, according to the present invention, it is possible to provide a coke oven with high productivity in which the volume of the carbonization chamber is increased as compared with that before dismantling. Moreover, according to this invention, since the total furnace height is the same coke oven as before dismantling, the existing incidental equipment of the furnace upper part can be used as it is. Therefore, the present invention has high applicability in the coke manufacturing industry.

DESCRIPTION OF SYMBOLS 1 Hearth support structure 2 Heat storage chamber 3 Combustion chamber 4 Coking chamber 5 Ceiling wall 6 Chimney 7 Fuel gas supply path 8 Air supply path H Coke furnace total furnace height Ha Heat storage chamber height Hb, I Furnace height (combustion) Chamber or carbonization chamber height)
Hd, B Height of furnace top deck Wb Width of combustion chamber Wc Width of carbonization chamber W, A Kiln core pitch of coke oven (= Wb + Wc)
Subscript 1: Number indicating that it is before dismantling Subscript 2: Number indicating that it is after reconstruction

Claims (3)

In the restructuring method of the chamber coke oven in which the heat storage chamber is arranged on the hearth structure, and the carbonization chamber and the combustion chamber are alternately arranged thereon,
(X) dismantling the carbonization chamber, combustion chamber, and heat storage chamber, leaving the hearth structure;
(Y) On the hearth structure, a heat storage chamber is constructed with a reduced height before dismantling,
(Z) A coke oven restructuring method characterized in that a carbonization chamber and a combustion chamber are built on the heat storage chamber to be higher by a reduction in the height of the heat storage chamber.   2. The method of rebuilding a coke oven according to claim 1, wherein the furnace core pitch (carbonization chamber width + combustion chamber width) is set larger than the furnace core pitch before dismantling.   A rebuilt coke oven, which is reconstructed by the coke oven reconstructing method according to claim 1.

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