JP2000219883A - Inhibition of carbon adhesion in coke oven and removal of sticking carbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for inhibiting carbon from sticking to the walls of a coke over and a removal of the carbon sticking to the top space of the coal over and a method for removing the carbon adhering to the wall and the like. SOLUTION: While coal is dry-distilled in a coke over the gas temperature, one or two or more of the gas pressure and the gas flow rate are altered tentatively in the flow of the gas evolved in the top space of the coke over to generate surfaces of discontinuity 13 on the pyrolyzed carbon sticking to the walls of the coke over and the adhesion of the carbon is suppressed thereby in the top space of the coke over. In addition, air is blown to the sticking carbon layers and/or mechanical shocks are given to the sticking carbon to readily remove the same.

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 adhesion of carbon adhering to a coke oven top space and a method for removing the adhering carbon when a coal is distilled in a coke oven and a coke for metallurgy is produced. About.

[0002]

2. Description of the Related Art When producing coke for metallurgy by dry-distilling coal in a coke oven, a hydrocarbon pyrolysis gas generated from coal during carbonization is further heated while moving in the coke oven. A part of the pyrolysis gas is decomposed to deposit carbon, and adheres to the wall surface together with the accompanying fine particles. Particularly in the furnace top space where the temperature is 800 ° C. or more, the generation of these carbons is remarkable, and the carbon adheres to the base of the riser, the furnace wall brick and the ceiling brick in the carbonization chamber. Since this deposited carbon causes obstruction of the operation of the coke oven, such as clogging of the riser pipe and clogging of the coke, it is indispensable for the stable operation of the coke oven to reduce the amount of deposited carbon or to remove the produced deposited carbon. . Here, the furnace top space means a space through which gas formed between the uppermost part of the coal bed charged into the coking chamber and the ceiling of the coking chamber and the base of the riser pipe.

[0003] The adhering carbon must be removed every time the coke carbonization is completed. The most common method of removing adhering carbon is a method of blowing and burning air onto high-temperature adhering carbon in a carbonization chamber to burn and remove it. When air is sprayed on the adhered carbon, the carbon is removed by combustion, and the removal is promoted by the carbon layer being peeled off by the impact of the blown air.

[0004]

In the method of removing deposited carbon by combustion alone, it takes a long time to sufficiently remove carbon when the amount of deposited carbon is excessive or when the deposited carbon is hardened. In short, the productivity of the coke oven is hindered. Therefore, in such a case, means for mechanically removing the adhered carbon by human power must be supplementarily used. In addition, from the viewpoint of improving the atmospheric environment and improving safety, it is preferable to reduce the application ratio of the combustion removal method as much as possible.

The present invention suppresses the adhesion of carbon adhering to a coke oven wall and makes it possible to easily remove carbon adhering to a coke oven top space, and a method for removing adhering carbon. The purpose is to provide.

[0006]

That is, the gist of the present invention is as follows. (1) The gas temperature, gas pressure, and gas flow rate of the coke oven top space 2 are temporarily measured during coal carbonization in the coke oven. Alternatively, a method for suppressing the adhesion of deposited carbon in a coke oven top space portion, wherein a discontinuous surface is generated in pyrolytic carbon generated from coal carbonization gas and adhered to a coke oven wall by changing two or more. (2) gas temperature in the coke oven top space 2;
The timing of changing one or two or more of the gas pressure and the gas flow rate is between 5 and 9 hours from the start of the dry distillation, and the sticking of the adhered carbon in the coke oven top space according to the above (1), Suppression method. (3) By introducing one or more of an inert gas, a hydrocarbon gas, carbon dioxide, and water vapor into the coke oven top space 2, the gas temperature of the coke oven top space
The method for suppressing adhesion of deposited carbon in a coke oven top space according to the above (1) or (2), wherein one or more of gas pressure and gas flow rate are changed. (4) After coal carbonization is performed by the method for suppressing adhesion of adhered carbon described in (1) to (3) above, air is blown onto the adhered carbon and / or a mechanical impact is applied to the adhered carbon to adhere. A method for removing adhered carbon in a coke oven, comprising removing carbon. It is.

According to the present invention, when the gas flow (gas flow rate, gas temperature) in the furnace top space 2 of the coke oven is changed during the carbonization of coal, the discontinuous carbon layer 12 generated at the time of the change is discontinuous. The feature is that it has been found that the surface 13 is generated, and it is possible to easily remove the attached carbon by utilizing this phenomenon.

As means for changing the gas flow in the furnace top space, a gas fluid such as an inert gas, a hydrocarbon gas, carbon dioxide, or water vapor is introduced into the furnace top space, and the gas flow rate in the furnace top space is changed. A method of changing the gas temperature or a method of changing the gas flow rate or gas temperature in the furnace top space by changing the pressure in the coking chamber of the coke oven can be used. Also, in a double-maine coke oven having two risers at each end of the carbonization chamber, gas is sucked from both risers at the beginning of the dry distillation, and after the start of the dry distillation, for example, 7 g
The gas flow in the furnace top space can be changed by changing to the single-main system in which the gas is sucked only from one of the risers after a lapse of time.

During coal carbonization, carbon is continuously being deposited on the coke oven furnace wall brick 11. As described above, when the gas flow in the furnace top space is changed during the carbonization of coal, it is considered that a large change occurs in the generation rate of pyrolytic carbon from the time of the change, as shown in FIG. 2 (b). A discontinuous surface 13 is generated in the deposited carbon layer 12 deposited like this. Since the discontinuous surface 13 has low mechanical strength and the thermal properties (expansion coefficient) of the deposited carbon before and after the discontinuous surface are different, the thermal impact (temperature change) or the mechanical impact is applied to the deposited carbon layer. The surface layer can be easily separated from the discontinuous surface.

As a means for applying a thermal shock to the deposited carbon layer 12, it is effective to blow air onto the deposited carbon. By blowing high-pressure air, the surface layer of the attached carbon is rapidly cooled and a thermal shock is applied, so that the surface layer separates at the discontinuous surface as a boundary. The carbon layer remaining after peeling can be burned and removed by blowing air.

The surface layer of the carbon layer having the discontinuous surface 13 according to the present invention can be easily removed even by mechanical impact. As a method for applying a mechanical impact, a method using human power, a method in which a hard powder or the like such as coke powder is made to collide with compressed air at a high speed as disclosed in Japanese Patent Application Laid-Open No. 60-214486, and the like can be used.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a chamber-type coke oven for producing metallurgical coke, the carbonization time for one coke production is usually 15 to 20 hours. During this time, for example, 1 mm to 3 mm of carbon adheres to the furnace wall of the furnace top space 2. Changes in gas flow (gas flow rate, gas temperature) for forming the discontinuous surface 13 in the attached carbon layer 12 are as follows:
It can be carried out once or several times during the carbonization. When the gas flow is changed once during the carbonization, it is effective to perform the gasification during the carbonization, that is, within 5 to 9 hours from the start of the carbonization. When the carbonization is performed within 5 hours from the start of the carbonization, the thickness of the carbon from the discontinuous surface 13 exceeds the thickness of the carbon from the carbon deposition starting surface to the discontinuous surface 13. The efficiency of peeling and removing the attached carbon by applying impact (temperature change) or mechanical impact is significantly reduced. On the other hand, when the time exceeds 9 hours, the thickness of carbon from the discontinuous surface 13 is reduced, so that the amount of carbon removed and removed is reduced, and the load on the removal of the carbon layer remaining after the removal is increased. In the case of performing a plurality of times, the required time for carbonization is almost equally divided to give a change in gas flow at each knot time.

When the gas flow is changed by introducing a gas fluid into the furnace top space, the gas fluid inlet 5
As shown in FIG. 1, it is preferable to dispose the gas in the furnace top space 2 in the carbonization chamber 1 on the side opposite to the side where the riser pipe 4 is disposed. This makes it possible to spread the effect of introducing the gas fluid over the entire area of the furnace top space 2. With the introduction of the gas fluid, the gas flow velocity in the furnace top space increases, and the gas temperature decreases.

The gas introduced into the furnace top space is preferably one or more of an inert gas, a hydrocarbon gas, carbon dioxide, and water vapor. With these gases, it is possible to change the gas flow while maintaining the non-oxidizing atmosphere in the carbonization chamber. As the inert gas, nitrogen gas is the most common. The introduction of steam may be performed by introducing water vapor as a gas or by spraying water into the furnace top space and vaporizing the water in the furnace top space.
The gas temperature in the furnace top space can be effectively cooled by the heat taken during evaporation.

The amount of gas introduced is to increase the gas flow rate flowing through the furnace top space at the time of gas introduction by 5% to 30%, or
The furnace top space temperature (average temperature) at the time of gas introduction is 30 ° C to 8
It is preferable to set the gas introduction amount to be equivalent to lowering by 0 ° C. When the amount of the introduced gas is small and the increase in the gas flow rate is less than 5% or the decrease in the gas temperature is less than 30 ° C., the generation of the discontinuous surface 13 formed in the adhered carbon layer 12 is insufficient. On the other hand, when the amount of introduced gas is large and the increase in the gas flow rate exceeds 30%, the fine powder from the top of the coal or coke layer charged into the coking chamber with the increase in the gas flow rate in the furnace top space Is rolled up and so-called carryover powder increases, which causes an increase in attached carbon. If the gas temperature drop exceeds 80 ° C., insufficient dry distillation near the surface layer of the coal and damage to the furnace wall bricks are feared. Further, it is not preferable because problems such as an increase in power when a large amount of gas is introduced into the coking chamber and an increase in load on the coke oven generated gas treatment equipment occur.

Since the amount of dry distillation gas generated in the coke oven changes every moment, the amount of gas passing through the furnace top space also changes accordingly. Therefore, it goes without saying that the specific gas introduction amount varies depending on the type and operation method of the coke oven, the operation rate of the furnace, the timing of introducing the gas, and the like.

The gas introduction duration is preferably 5 to 15 minutes. When the introduction time is less than 5 minutes, the discontinuous surface is not sufficiently formed because the generation of the adhering carbon is not sufficient. On the other hand, if the introduction time exceeds 15 minutes, problems such as an increase in the power for introducing the gas into the coking chamber and the load on the coke oven generated gas treatment equipment occur, which is not preferable.

The gas generated in the carbonization chamber during coal carbonization is:
As shown in FIG. 1, a rising pipe 4 provided in the upper part of the carbonization chamber 1
The gas is sucked by a gas blower 7 outside the furnace provided at the end of the exhaust port passing through. In each of the coking chambers, the pressure control in the coking chamber in the furnace top space is usually performed by controlling the pressure of the water supplied from the water injection nozzle 16.

At the time of charging coal, high-pressure low-temperature water is generally sprayed by a nozzle 16 installed on a riser to cope with dusting of the coal and rapid generation of gas. At the base of the riser, for example-
A negative pressure of about 30 to -100 mm water column is used. During normal carbonization other than charging coal, the pressure in the carbonization chamber is adjusted to, for example, about +5 to 7 mm water column with respect to the atmospheric pressure. This is because if the degree of negative pressure is large, air may be sucked into the carbonization chamber, which not only causes a decrease in the calories of COG (coke oven gas), but also causes a danger of explosion due to mixing of oxygen gas. Due to reasons such as becoming high.
If the gas pressure inside the coke oven is too high, the carbonized gas inside the coking chamber may leak from the gap between the charging lid and the charging port and be released to the atmosphere, which is not preferable in terms of environmental protection.

In the present invention, when the pressure in the carbonization chamber is changed during carbonization, the gas pressure is increased by +5 to -50 with respect to the atmospheric pressure in the same manner as when charging coal or during normal carbonization.
mm water column. As a result, the gas flow rate in the furnace top space increases by about 5% to 30%, and the gas temperature can be reduced by about 30 ° C. to 80 ° C. at the average temperature of the furnace top space. The duration for changing the pressure in the carbonization chamber is preferably the same as the duration for introducing gas into the furnace top space. This is because if the duration of the pressure control is short, the formation of the discontinuous surface becomes insufficient due to insufficient generation of the adhering carbon, and if the duration of the pressure control is long, air may be sucked into the carbonization chamber. This is because it is not preferable for the same reason as described above.

As described above, the discontinuous surface 13 is formed in the adhered carbon layer 12 generated on the furnace wall by changing the gas flow in the furnace top space 2 during coal carbonization. After the coke that has been carbonized has been discharged to the outside of the furnace, an air discharge nozzle is inserted into the carbonization chamber, and high-speed air is blown onto the adhered carbon layer 12 adhered to the furnace wall brick 11, whereby the surface layer from the discontinuous surface 13 is removed. The carbon layer on the side can be peeled off. Although the carbon layer on the furnace wall side from the discontinuous surface does not peel off even by air blowing and remains on the furnace wall, the carbon layer remaining on the furnace wall must be burnt and removed by continuously blowing air. Can be. As a method of blowing air, it is possible to apply a method conventionally used for removing carbon adhering to a riser base or a ceiling portion. That is, for the base of the riser, use of a riser cleaning device having a compressed air injection hole composed of an air pipe, an annular pipe, and a number of nozzles as disclosed in Japanese Utility Model Application Laid-Open No. 56-126465 is considered. Can be In addition, for example, Japanese Patent Laid-Open No.
As shown in Japanese Patent No. 879, a method is conceivable in which a nozzle is disposed at the front of a moving frame of a pusher, and compressed air is blown from the nozzle onto the adhered carbon.

The thickness of the deposited carbon layer varies depending on the type and operation rate of the coke oven and the properties of the charged coal. For example, the thickness of the carbon layer is about 50 to 500 μm per one cycle of the dry distillation on the furnace wall at the top space of the carbonization chamber. The discontinuous surface is formed at a position of 30 to 350 μm from the brick surface. Similarly, it is about 1 to 10 mm at the base of the riser pipe, and the discontinuous surface is about 0.7 to 7 mm from the brick surface. Therefore, approximately 30% of the adhered carbon is separated and removed by the impact force of compressed air blowing. The remaining attached carbon can be burned off by oxygen in the air. The time required for carbon removal can be reduced to 70% as compared with the conventional method in which a discontinuous surface is not formed on the adhered carbon layer.

The attached carbon can also be removed by applying a mechanical impact to the attached carbon layer. When a mechanical impact is applied to the adhered carbon layer with a metal rod or the like, or in the case of a conventional carbon layer without a discontinuous surface, the carbon cannot be easily peeled off because it is fixed to the furnace wall. In the case of the carbon layer having a discontinuous surface according to the invention, the carbon layer can be easily peeled off by mechanical impact. Specifically, a method in which a hard granular material such as coke powder is made to collide with compressed air at a high speed as disclosed in Japanese Patent Application Laid-Open No. Sho 60-221486 can be used.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention was applied to a coke oven of a furnace type. The operating rate of the coke oven was 115%, the average flue temperature was 1200 ° C., and the carbonization time was 18.5 hours before the fire was burned out. The properties of the charged coal were such that the volatile matter content was 26.6%, the ash content was 8.2%, the particle size was 39.5% under, and the coal charge amount was 22.3 tons (dry).

In Example 1 of the present invention, nitrogen gas was introduced from the gas introduction pipe 5 shown in FIG. The gas introduction rate was 2 m ³ / min (25 ° C., atmospheric pressure conditions). As a result, the gas flow velocity in the furnace top space during gas introduction is 1.5 to 3 m / sec (850
° C, atmospheric pressure condition), the gas flow velocity increases by about 25% compared to before the gas introduction, and the temperature is about 50 ° C on average in the furnace top space.
Dropped.

In Example 2 of the present invention, the pressure in the carbonization chamber was controlled by injecting high-pressure water from the nozzle 16 for 12 minutes from the lapse of 8 hours after charging the coal.
By this operation, the pressure in the carbonization chamber (the base of the riser) is +5 m
m water column (versus atmospheric pressure) to -25 mm water column (versus atmospheric pressure). As a result, the gas flow velocity in the furnace top space during the pressure change was 1.3 to 2.5 m / sec (850 ° C., atmospheric pressure conditions).

In the comparative example, normal coke oven operation was performed without gas introduction or pressure change.

As a method for removing the adhering carbon, a conventionally used riser cleaning device was used. The riser cleaning device has a compressed air injection hole composed of a number of nozzles in an annular tube, supplies air from the air tube to the annular tube, and blows air from the compressed air injection hole to the furnace wall. The carbon removal was performed by removing carbon adhering to the riser tube base every one cycle of dry distillation.

The cross section of the deposited carbon layer in Examples 1 and 2 of the present invention was as shown in FIG. 2 (b), and the cross section of the deposited carbon layer in the comparative example was as shown in FIG. 2 (a). When this attached carbon was removed by the above method,
The time required for complete removal was 4 minutes for Inventive Example 1, 5 minutes for Inventive Example 2, and 8 minutes for Comparative Example, indicating that the present invention exerts the effect of accelerating the removal of attached carbon. Was completed.

[0030]

According to the present invention, a discontinuous surface is formed in the carbon layer adhering to the furnace wall by introducing gas into the coke oven furnace top space temporarily during coal carbonization or by changing the pressure in the carbonization chamber. Thus, it was possible to suppress the adhesion of the attached carbon. As a result, it has become possible to easily remove the attached carbon by blowing air onto the attached carbon and applying a mechanical impact to the attached carbon.

[Brief description of the drawings]

FIG. 1 is a sectional view of a coke oven carbonization chamber embodying the present invention.

FIGS. 2A and 2B are cross-sectional views showing an attached carbon layer, in which FIG. 2A is a sectional view showing a conventional attached carbon layer, and FIG. 2B is a sectional view showing an attached carbon layer having a discontinuous surface according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coalization room 2 Furnace top space part 3 Coal 4 Rise pipe 5 Gas inlet 6 Dry main 7 Gas blower 8 Rise pipe gas flow 9 Coke oven generated gas flow 10 Introduced gas flow 11 Furnace wall brick 12 Adhered carbon layer 13 Discontinuous Surface 14 Adhered carbon surface 15 Curved pipe 16 Nozzle for water injection 17 Pressure regulating valve 18 Water supply pipe 19 Base of rising pipe

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ikuo Komaki 20-1 Shintomi, Futtsu City Nippon Steel Corporation Technology Development Division (72) Inventor Tatsuya Kudo 12 Nakamachi, Muroran City Nippon Steel Corporation Muroran Works

Claims (4)

[Claims] At least one or more of a gas temperature, a gas pressure, and a gas flow rate in a coke oven top space portion are temporarily changed during coal carbonization in a coke oven to generate from a coal carbonization gas to form a coke oven wall. A method for suppressing the adhesion of deposited carbon in a coke oven top space, wherein a discontinuous surface is generated in the pyrolytic carbon attached to the surface. 2. The timing of changing one or more of gas temperature, gas pressure and gas flow rate in the coke oven top space portion is set to 5 to 9 hours from the start of dry distillation. 2. The method for suppressing adhesion of adhered carbon in a coke oven top space part according to 1. 3. A gas temperature, a gas pressure, and a gas pressure in the coke oven top space by introducing one or more of an inert gas, a hydrocarbon gas, carbon dioxide, and steam into the coke oven top space. 3. The method according to claim 1, wherein one or two or more gas flow rates are changed. 4. The method of claim 1, wherein after the coal is carbonized, air is blown onto the deposited carbon and / or a mechanical impact is applied to the deposited carbon. A method for removing adhering carbon in a coke oven top space portion, characterized by removing carbon.