JPH07268327A - Method for suppressing lowering of temperature in regenerator of coke oven - Google Patents

Abstract

PURPOSE:To suppress the depression of the temperature in a regeneration chamber in the case of lowering the operation rate of a coke oven. CONSTITUTION:In the case of introducing a fuel gas into a regeneration chamber 2, a prescribed amount of fuel gas is extracted from a fuel gas supplying main pipe 10 and burned in a combustion furnace 14. The generated hot combustion gas is returned to the fuel gas supplying main pipe 10 and mixed with the fuel gas to raise the temperature of the fuel gas and the heated fuel gas is introduced into the regeneration chamber 2. In the case of introducing air into the regeneration chamber 2, a prescribed amount of fuel gas is extracted from the fuel gas supplying main pipe 10 and burned in a combustion furnace 15. The generated hot combustion gas is mixed with air and the heated air is introduced into the regeneration chamber 2. The lowering of the temperature of the regeneration chamber caused by the introduced gas can be suppressed by preheating the fuel gas and air, before introducing into the regeneration chamber and, accordingly, the temperature of the regeneration chamber can be maintained above the lower limit and the furnace body can be protected even by lowering the operation rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing a temperature drop in a heat storage chamber in a chamber coke oven.

[0002]

2. Description of the Related Art In a chamber furnace type coke oven, a carbonization chamber in which coal is charged and carbonized and a combustion chamber in which a fuel gas is supplied to heat the carbonization chamber for combustion are arranged alternately. A heat storage chamber that preheats the fuel gas and the air supplied to the combustion chamber is provided below these.

FIG. 2 is a diagram showing an example of the coke oven in which the combustion chamber and the heat storage chamber are divided into two. This figure shows a schematic cross section of a coke oven passing through the furnace length direction of the combustion chamber (one end on the coke side and the other end on the extruder side). In the figure, 2 is a heat storage chamber, 3 is a combustion chamber, and the arrows indicate the gas flow direction. The heat storage chamber 2 and the combustion chamber 3 are each provided with a partition between the coke side and the extruder side.
It is divided into compartments. The names of these two compartments differ depending on the operating state of the furnace. When the gas flow is as shown in FIG. 2, the right compartment is called the rising portion and the left compartment is called the drop portion.

Fuel gas and air are respectively supplied to the heat storage chamber 2 at the rising portion, preheated, and then rise to rise to the combustion chamber 3
It is mixed and burned inside. The burned gas descends in the combustion chamber 3 of the dropping section and enters the heat storage chamber 2, where heat is recovered in the heat storage chamber 2 and then released to the atmosphere. Then, after a predetermined time (usually 15 minutes to 30 minutes) has elapsed, the supply of fuel gas and air is switched to the opposite compartment, and the gas flow is reversed. By this gas flow switching (combustion switching), the rising portion and the withdrawal portion are switched.

By the way, in the operation of the coke oven,
Occupancy rates may need to be reduced. In order to reduce the operating rate, conventionally, the amount of fuel gas supplied is reduced to lower the carbonization temperature and the carbonization time is lengthened.

[0006]

When the supply amount of the fuel gas is sequentially reduced in order to reduce the operating rate, the temperature of the heat storage chamber also gradually decreases, and when the temperature decrease exceeds a certain limit, next Problems such as those mentioned above occur.

The heat storage chamber is provided with a large number of partitions inside,
The fuel gas preheating chambers and the air preheating chambers are alternately arranged, and heat storage bricks are stacked and filled therein. The partition wall that divides the heat storage chamber into a fuel gas preheating chamber and an air preheating chamber has an upper part made of high temperature brick such as silica stone brick and a lower part made of low temperature brick such as chamotte brick.

Among the bricks forming the partition wall, a high temperature silica brick has a small coefficient of thermal expansion in a high temperature region, but has a property of a large coefficient of thermal expansion in a low temperature region. Therefore, when the temperature of the silica stone brick portion of the partition wall drops beyond the limit, cracks occur in the partition wall. If there is a crack in the partition wall of the heat storage chamber, there is a risk of explosion due to the mixture of air and fuel gas passing through this partition wall. In order not to cause such a problem, it is necessary to maintain at least the temperature of the boundary portion between the high temperature brick and the low temperature brick (this is called a slip joint) at a predetermined value or higher.

As described above, in the coke oven, the operation can be performed only under the condition that the temperature of the slip joint can be maintained above the lower limit temperature, and the temperature of the slip joint approaches the lower limit temperature. In other words, the operation is the lower limit operation that can reduce the utilization rate.
The lower limit temperature of the slip joint is the transformation point (573) at which quartz in the silica brick changes from a high temperature type to a low temperature type.
C)).

An object of the present invention is to provide a method capable of suppressing a temperature drop in the heat storage chamber due to a decrease in operating rate.

[0011]

According to the present invention, when the fuel gas or the combustion air to be supplied to the combustion chamber is introduced into the heat storage chamber and preheated, the temperature of the fuel gas or the combustion air is raised in advance and the temperature is raised. This is a method for suppressing the temperature decrease in the coke oven heat storage chamber, which introduces the fuel gas or the combustion air to the heat storage chamber.

When the fuel gas or the combustion air is introduced into the heat storage chamber for preheating, a part of the fuel gas supplied to the combustion chamber is branched and burned in advance, and then the high temperature gas is used as the original fuel. It is a method for suppressing a temperature decrease in a coke oven heat storage chamber, which is mixed with a gas flow or a combustion air flow to raise the temperature of fuel gas or combustion air and then introduces the temperature into a heat storage chamber. Further, it is a method for controlling the temperature of the coke oven heat storage chamber, in which the temperature of the slip joint portion of the heat storage chamber tension control brick is controlled to 573 ° C. or higher.

[0013]

Since the temperature of the fuel gas or the combustion air introduced into the heat storage chamber is lower than the temperature of the heat storage chamber, the temperature of the lining brick is cooled by the introduced gas or air.
Here, since the temperature drop amount of the lining brick is reduced by introducing the fuel gas or the air whose temperature has been raised in advance into the heat storage chamber, the temperature drop amount in the heat storage chamber can be suppressed.

Further, after a part of the fuel gas is branched and burned, the high temperature gas is mixed with the original fuel gas flow or the combustion air flow to simply and reliably generate the fuel gas or the combustion air. The temperature can be raised. Further, by controlling the temperature of the slip joint portion in the heat storage chamber to 573 ° C. or higher by the above method, it is possible to prevent cracking of the high temperature silica stone brick.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an illustration of an embodiment of the present invention. In FIG. 1, 1 is a coke oven, 2 is a heat storage chamber, 3 is a combustion chamber, 10 is a fuel gas supply system, and 11 is an air supply system. Combustion furnaces 14 and 15 are attached to the fuel supply system 10 and the air supply system 11, respectively. This combustion furnace 1
The high temperature combustion gases generated in 4 and 15 are supplied to the fuel supply main 12 and the air supply main 13, respectively. 18 and 19 are fans, and 20 and 21 are gas mixers.

In the present embodiment, the heat storage chamber 2 of the coke oven
When introducing the fuel gas and the combustion air into the chamber, the following operation is performed. First, when introducing the fuel gas, a predetermined amount of fuel gas is extracted from the branch pipe 16 of the fuel supply system and supplied to the combustion furnace 14 to be burned to generate high temperature combustion gas. This high-temperature combustion gas is used for the fuel supply main 12
And merges with the fuel gas stream. By mixing this high temperature combustion gas, the temperature of the fuel gas introduced into the heat storage chamber 2 rises. When introducing combustion air, a predetermined amount of fuel gas is extracted from the branch pipe 17 of the fuel supply system and supplied to the combustion furnace 15 for combustion. The generated high temperature combustion gas is mixed with room temperature air to raise the temperature of the air. This heated air is introduced into the heat storage chamber as combustion air.

Next, the result when the method shown in FIG. 1 is carried out will be described. (Example) As a coke oven, a chamber furnace type, a rich gas (C
The test was conducted using a double type Karlstil furnace (a six-stage combustion type, and a combustion chamber and a heat storage chamber were divided into two types) capable of using both gas) and poor gas (blast furnace gas). This coke oven has a carbonization chamber with a height of 7.6 m and a width of 0.45.
m, the depth was 17 m, and the amount of coal charged at one time was about 38 t (when the water content was 8%). As fuel gas, M
Gas (mixed gas of blast furnace gas and C gas) was used.

As shown in Table 1, the operating conditions were as follows: the amount of coal charged was 38 T / kiln / cycle, and the operating rate was greatly reduced. The carbonization time is 28 as shown in Table 1.
It was carried out in a time of 24 minutes (fall time 24 hours 24 minutes). In this example, part of the fuel gas was extracted and burned in two systems. The high temperature combustion gas of this system was combined with the original fuel gas flow and introduced into the heat storage chamber. The high temperature combustion gas of the other system was mixed with air and introduced into the heat storage chamber as combustion air. The temperature of each gas after the temperature rise when it was introduced into the heat storage chamber was 140 ° C for fuel gas and 125 ° C for combustion air.
It was ℃.

The results of the implementation are shown in the lower column of Table 1. In the above operation, the temperature of the slip joint in the heat storage chamber was 575 ° C.
And the lower limit temperature of the slip joint was higher than 573 ° C. As a result, it was possible to prevent the occurrence of cracks in the high temperature silica bricks even under the low operating rate condition of the charging coal amount of 38 T / kiln / cycle.

(Comparative Example 1) An operation was performed without raising the temperature of the fuel gas and combustion air introduced into the heat storage chamber. The same coke oven as in the example was used, and the operating conditions were as shown in Table 1, except that the temperature of the gas introduced into the heat storage chamber was not raised. Drying time is the same as in Example 2
It carried out in 8 hours and 24 minutes (fall time was 24 hours and 24 minutes).
In this operation, the temperature of each gas when introduced into the heat storage chamber was 40 ° C. for fuel gas and 25 ° C. for combustion air.

The results of the implementation are shown in the lower column of Table 1. In this operation, the temperature of the slip joint of the heat storage chamber is 525.
The temperature was significantly lower than the lower limit temperature 573 ° C. of the slip joint. As a result, the amount of coal charged was 38T / kiln.
It was not possible to prevent the occurrence of cracks in the high temperature silica stone bricks even under low operating rate conditions. Further, it was found that the operation for setting the fire fall time to the above time (24 hours 24 minutes) cannot be carried out in the actual operation.

(Comparative Example 2) The same coke oven as in the example was used, and operation was performed without raising the temperature of the fuel gas and combustion air introduced into the heat storage chamber. The implementation conditions were as shown in Table 1. In this operation, the temperature of each gas when introduced into the heat storage chamber was 40 ° C. for fuel gas and 25 ° C. for combustion air.

The results of the implementation are shown in the lower column of Table 1. In this operation, the temperature of the slip joint in the heat storage chamber was 575
C., which was above the lower limit temperature 573.degree. C. of the slip joint, but this operation was almost the lower limit of the operating rate.

As is clear from the results of the above Examples and Comparative Examples, in the Examples, it was possible to operate at an operating rate of about 24 hours for the burn-down time. However, in the comparative example, the operation of the burn down time of 21 hours was the limit to reduce the operating rate (Comparative example 2).

In the above embodiment, only the result when the combustion chamber and the heat storage chamber are applied to a two-division type coke oven has been described, but the present invention is applied to other types of coke ovens. It is possible to obtain the same effect as the above embodiment.

The present invention is not limited to the above-mentioned temperature raising method as means for raising the temperature of the fuel gas or the combustion air. The hot gas generated from other equipment may be introduced and mixed, or may be heat-exchanged with the hot gas generated from other equipment. Further, heating by heat exchange with the combustion exhaust gas of the coke oven and means for mixing high temperature gas may be used together. Further, even when a part of the fuel gas is extracted and burned, it is not always necessary to separately burn the fuel gas and the combustion air separately for combustion.

[0027]

[Table 1]

[0028]

According to the present invention, since the temperature of the fuel gas or the combustion air is raised in advance and then introduced into the heat storage chamber, the amount of temperature drop in the heat storage chamber becomes small. Further, since the temperature is raised by using the fuel gas as the heat source, the temperature can be raised by a low cost and simple equipment. Further, since the temperature of the slip joint part is controlled to be equal to or higher than the transformation point temperature, the furnace body is protected even if the operating rate is significantly reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is a schematic explanatory diagram showing an example of a coke oven.

[Explanation of Codes] 1 Coke oven 2 Combustion chamber 3 Heat storage chamber 10 Fuel gas supply system 11 Air supply system 12 Fuel gas supply main 13 Air supply main 14,15 Combustion furnace 16,17 Fuel gas branch pipe 18,19 Fan 20,21 gas mixer

Claims (3)

[Claims] 1. When the fuel gas and the combustion air to be supplied to the combustion chamber are introduced into the heat storage chamber and preheated, the temperature of the fuel gas or the combustion air is raised, and the temperature of the fuel gas and the combustion air is raised. Method for suppressing temperature drop in the coke oven heat storage chamber introduced into the heat storage chamber. 2. A part of the fuel gas supplied to the combustion chamber is branched, and this is combusted to obtain a high temperature gas, and this gas is mixed with a fuel gas flow or a combustion air flow to raise the temperature, and this temperature is raised. The method for suppressing a temperature decrease in the coke oven heat storage chamber according to claim 1, wherein the fuel gas flow or the combustion air is introduced into the heat storage chamber. 3. The coke oven heat storage chamber temperature control method according to claim 1, wherein the temperature of the slip joint portion of the heat storage chamber brick is controlled to 573 ° C. or higher.