JPH09316452A - Control over grade of tar formed as by-product in production of coke - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the efficient production of a tar formed as a by-product when baking a raw material coal and producing coke in response to the quantity demanded in good yield. SOLUTION: When the operation rate of a coke oven, properties of a raw material coal such as the moisture content or volatile content and the required production amount of a tar formed as a by-product are determined, the set reference temperature for baking coke is set at a value computed by the simulation in relation to the heat transfer and reaction in a carbonization chamber of the coke oven and the set reference temperature is maintained to control the production yield of the tar formed as the by-product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the yield of by-product tar in the production of coke, and more specifically, in a coke oven for burning product coal to produce product coke, particularly in a chamber furnace type coke oven. The present invention relates to an improvement in a yield control method of by-product tar obtained as a by-product when coke is produced by a uniform heating method in which a room temperature is kept constant.

[0002]

2. Description of the Related Art Generally, in the case of this type of chamber furnace type coke oven (hereinafter, simply referred to as "coke oven"), the raw material coal is discharged as product coke (hereinafter simply referred to as "coke") after completion of carbonization treatment. The time required for each operation up to this point is uniquely determined by the operating rate of the coke oven, and the time required for each operation is called a "firing cycle".

Thus, the firing cycle in the coke oven is the <burning time> from the start of the charging of the raw coal to the end of the carbonization process, the so-called fire burn, and the time from the burn burn to the discharge of coke. Placement time>, and a certain reference temperature is set in advance as the temperature of the combustion chamber at this time, and during operation, fuel supply is controlled so that the reference temperature can be maintained. .

Here, in the conventional case, from the viewpoint of energy saving, the above-mentioned reference temperature is set to a minimum value <coke quality so that the quality of coke can be maintained as expected in order to reduce the amount of heat energy required for dry distillation. It is said that it is better to set the storage time as a target and set it as low as possible. Therefore, when adjusting the reference temperature in response to fluctuations in the operating rate of the coke oven, the water content and the volatile matter of the raw coal, the reference temperature should always be maintained at the shortest <dwell time>. The temperature change rate obtained from the above is used.

That is, the conventional setting of the reference temperature for controlling the fuel supply to the coke oven is aimed at maintaining the quality of the coke and reducing the amount of heat required for carbonization, and the by-product tar obtained as a byproduct of carbonization of the raw coal. In the present situation, (hereinafter, simply referred to as tar) is left to rest.

[0006]

As described above, in setting the reference temperature in the operation of the coke oven, it is desirable to reduce the amount of heat energy required for carbonization from the standpoint of energy saving. From the perspective of effective utilization of tar generated from the carbonization chamber,
When the demand for tar is high, the decomposition of the tar itself is suppressed and recovered in the form of the tar itself. When the tar is in excess supply, the decomposition of the tar itself is promoted and the tar It can be said that it is more desirable to collect in the form of coke.

That is, in the conventional method for setting the reference temperature, the target reference temperature is lowered to the shortest <dwell time> at which the quality of the coke is maintained, so that a positive correlation with the reference temperature is obtained. Although the amount of heat energy required for carbonization can be reduced, the amount of tar generated from the carbonization chamber increases because it has a negative correlation with the reference temperature, and as a result, it is independent of the balance of the tar itself. However, there is a problem that the tar tends to increase production.

The present invention has been made in order to solve the above-mentioned conventional problems.
It is an object of the present invention to provide a yield control method of by-product tar in coke production, which enables efficient production of tar generated as a by-product with high yield corresponding to demand when coking coal from coking coal. .

[0009]

In order to achieve the above-mentioned object, the inventors of the present invention continued their earnest development efforts, and as a result, carried out calculations using a simulation model of heat transfer and reaction in the coke oven carbonization chamber, Within the temperature range where coke quality is maintained, obtain the reference temperature of the combustion chamber of the coke oven or the reference temperature of the upper void of the carbonization chamber, or the reference temperature of the riser pipe, where the tar balance is the same. The inventors have found that the conventional problems described above can be improved by controlling any of these reference temperatures, and have completed the present invention.

In the modeling of the raw coal in the carbonization process, the raw coal is softened and melted to metaplast, which is re-solidified into semi-coke to generate gas and tar, and A so-called sequential first-order reaction model is known in which the semi-coke releases a gas rich in hydrogen to form coke. On the other hand, in a coke oven, heating is performed through the heating walls on both sides of the carbonization chamber, and the generated heat is gradually transferred from the both side walls of the carbonization chamber toward the inner center. The heat transfer model is also well known. Furthermore, although models that combine these sequential first-order reaction models and heat transfer models are also known, each of these models is sufficient to estimate the yield of tar generated during the firing of coking coal. It cannot be said that.

Therefore, the present inventors have made a detailed study on the progress of dry distillation of the raw coal in the carbonization chamber, and the rate of gas evolution and the composition change of the evolved gas and the rate of tar evolution accompanying the carbonization treatment. , It was possible to estimate the yield of tar under various operating conditions.

FIG. 1 shows an outline of a reaction model in the present invention, and FIG. 2 shows an outline structure of an experimental furnace apparatus (small-scale carbonization test furnace apparatus) corresponding to this reaction model.
Here, the reaction model according to the present invention is characterized in that, in addition to the conventional sequential first-order reaction model, in this case, the reaction water generated during the thermal decomposition reaction of tar and the thermal decomposition reaction of the raw coal is also taken into consideration. Is.

In the reaction model of FIG. 1 and the structure of the corresponding experimental furnace apparatus of FIG. 2, the carbonization chamber 32 of the furnace apparatus 31 is used.
The raw coal 11 charged therein is subjected to a pyrolysis reaction to be carbonized from the metaplast 12 through the process of semi-coke 13 and taken out as coke 14. Further, in this process, the gases 15a and 15b are respectively recovered, and the tar 16 and the reaction water 17 are generated during the thermal decomposition reaction.

The tar 16 generated by the thermal decomposition reaction of the raw coal 11 partially flows toward the center of the carbonization chamber 32 and is condensed in the bed of the low-temperature raw coal 11. On the other hand, most of the tar 15 is directed toward the heating wall 33 side and in the layer of the semi-coke 13 having a high temperature and the coke 1
There is also tar 16 that remains unreacted, and flows into the layers of No. 4 in sequence and is further thermally decomposed to release heavy gas (CmHn) 18 to become tar 16a having high specific gravity.

Then, a part of the tar 16a is released as gas by in-situ thermal decomposition and then similarly taken out as deposit coke 14a, and at the same time, crude gas oil 19 and methane (CH ₄ ) 20 produced by the reaction are discharged. And hydrogen (H ₂ ) 21 and unreacted tar 16a
Etc. are collected.

Further, the tar 16b of the other part that has been stopped becomes unable to exist as a gas as the gas is released, and the tar 16b is stopped in the coke 14 and is deposited in the deposit coke 1
4b, and likewise methane (CH
₄ ) 20 and hydrogen (H ₂ ) 21 are recovered.

Further, the heavy gas 18 is contained not only in the thermal decomposition reaction of the tar 16 but also in the gas 15a generated in the thermal decomposition reaction of the raw coal 11.
With respect to the heavy gas 18, hydrogen (H ₂ ) 21 generated by the thermal decomposition reaction by passing through the layer of the semi-coke 13 and the layer of the coke 14 is recovered, and again as the deposit coke 14c. In addition to being taken out, the unreacted heavy gas 18 is also recovered.

On the other hand, the inventors of the present invention changed the furnace temperature of the secondary decomposition variously by using the experimental furnace apparatus of FIG. 2 so that the reaction rate constant k in each reaction in the reaction model of FIG. to obtain the activation energy and frequency factor for determining the ₁ to k _7. The reaction water 17 generated during the thermal decomposition reaction of the raw coal 11 also flows to the heating wall 33 direction side at a certain ratio, and the temperature is 700 to 800 ° C.
The water gasification reaction is caused by passing through the layer of the coke 14 as described above, and the activation energy and the frequency factor for determining the reaction rate constant k ₈ at this time were also obtained.

In FIG. 3, the furnace temperature for the primary decomposition is 5 ° C. /
Experiments were carried out on the time-dependent change in the gas generation rate (a) and the time-dependent change in the gas composition (b) when the furnace temperature for the secondary decomposition was kept constant at 825 ° C. while the temperature was raised to 1000 ° C. in min. The result and the calculation result using the reaction model are shown. There was a good agreement between these experimental results and calculation results, and it was confirmed that they can be used as a reaction model for solving the above-mentioned problems.

Generally, in the structure of the coke oven, the portion where the tar 16 and the heavy gas 18 are thermally affected is in the semi-coke 13 layer when these are generated and flow toward the heating wall 33 side. And the wall of the coke 14 and the wall surface of the coke 14 when flowing upward along the heating wall 33.
A void with the layer, an upper void of the carbonization chamber 32, and the like. In the reaction model, the layer of the coking coal 11 and the layer of the coke 14 are considered in one dimension from the center to the heating wall 33. Therefore, in developing the reaction model in an actual coke oven, This is taken as an average value of the filling portion of the raw coal 11 including the void portion between the heating wall 33 and the layer of the coke 14, and the upper void portion of the carbonization chamber 32 corresponds to each retention time. In addition to dividing into sections, the tar and the generated gas obtained by calculating the filling portion of the raw coal 11 are added to the tar and the generated gas flowing in each section, and the thermal decomposition reaction is calculated in each section. However, the reaction rate formula here is
Of the coke 14 layer.

Using the simulation model created as described above, a standard operation was carried out at a set reference temperature with a volatile matter content of 27%, a water content of 9%, and a fixed standing time at various coke oven operating rates. Calculation was performed under the conditions. The result at this time is shown in FIG. FIG. 4 shows the actual value and the calculated value for the yield of tar (a) and the amount of gas generated per ton of coking coal converted to 4700 kcal / Nm ³ (b), and both are in good agreement. Therefore, the effect of the embodiment of the present invention can be easily confirmed here.

That is, the invention according to claim 1 of the present invention is such that when the operating rate of the coke oven, the properties of the raw material coal such as water and volatile matter, and the required amount of by-product tar are determined,
The set reference temperature for coke firing is a value calculated by simulation relating to heat transfer and reaction in the coke oven carbonization chamber, and the set reference temperature is maintained to control the production yield of by-product tar. It is a method for controlling the yield of by-product tar in coke production.

Therefore, in the yield control method for the by-product tar according to the first aspect, the set reference temperature for coke firing is set and maintained at the value calculated by the simulation. Yield is controlled as expected.

Further, the invention according to claim 2 of the present invention is such that when the operating rate of the coke oven, the properties of the raw material coal such as water content and volatile content, and the required production amount of by-product tar are determined, In order to make the temperature in the upper void portion of the furnace carbonization chamber a value calculated by a simulation relating to heat transfer and reaction in the carbonization chamber, the temperature in the upper void portion of the carbonization chamber is set to a reference temperature value corresponding to the calculated value. A method for controlling the yield of by-product tar in coke production, which is characterized by maintaining and controlling the production yield of by-product tar at the reference temperature value.

Therefore, in the yield control method for by-product tar according to the second aspect, the temperature in the upper void portion of the coke oven carbonization chamber is set to a value calculated by simulation, and therefore the temperature in the upper void portion corresponds to the calculated value. The production yield of the by-product tar is controlled as expected because it is maintained at the standard temperature value.

The invention according to claim 3 of the present invention is the control method according to claim 2, in which a required amount of air is introduced into the upper void portion of the carbonization chamber, and is generated during coke firing. A method for controlling the yield of by-product tar in coke production, which comprises burning a part of the gas and / or the by-product tar and maintaining the temperature in the upper void portion at the reference temperature value by the combustion.

Therefore, in the yield control method for by-product tar according to claim 3, in the control method according to claim 2,
Since air is introduced into the upper void portion to burn some of the generated gas and / or the by-product tar to maintain the temperature in the upper void portion at the reference temperature value, the production of the by-product tar is similarly performed. Yield is controlled as expected.

Further, the invention according to claim 4 of the present invention is such that when the operating rate of the coke oven, the properties of the raw material coal such as moisture and volatile matter, and the required production amount of by-product tar are determined, In order to make the temperature in the furnace riser pipe a value calculated by a simulation of heat transfer and reaction in the coke oven carbonization chamber, the temperature in the riser pipe is maintained at a reference temperature value corresponding to the calculated value by external heating. Then, the yield control method of the by-product tar in coke production is characterized in that the production yield of the by-product tar is controlled by the reference temperature value.

Therefore, in the yield control method of the by-product tar according to the fourth aspect, since the temperature in the riser pipe of the coke oven is set to the value calculated by the simulation, the temperature in the riser pipe is set to the reference temperature value corresponding to the calculated value. Since it is maintained, the production yield of by-product tar is controlled as expected.

Further, the invention according to claim 5 of the present invention is such that when the operating rate of the coke oven, the properties of the raw material coal such as water and volatile matter, and the required production amount of by-product tar are determined, In order to bring the temperature in the furnace carbonization chamber to a value calculated by a simulation relating to heat transfer and reaction in the carbonization chamber, a part of the by-product tar generated during coke firing is mixed with the coking coal at a ratio calculated by the simulation. Combustion, the temperature in the carbonization chamber is maintained at a reference temperature value corresponding to the calculated value by the combustion, and the production yield of the by-product tar is controlled by the reference temperature value. This is a yield control method.

Therefore, in the yield control method of the by-product tar according to the fifth aspect, since the temperature in the coke oven carbonization chamber is set to the value calculated by the simulation, a part of the by-product tar is calculated at the calculation ratio by the simulation. Since the mixed combustion is performed to maintain the temperature in the carbonization chamber at the reference temperature value corresponding to the calculated value, the production yield of the by-product tar is controlled as expected.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a reference temperature setting in the method for controlling the yield of by-product tar according to the present invention will be described below in detail with reference to FIGS. 1 to 4 and FIG.

FIG. 5 shows various coke oven operating rates in this embodiment, which are calculated by changing the set reference temperature, and show changes in the tar yield (a) and changes in the gas generation amount (b). Is shown.

In the embodiment shown in FIG. 5, as an example, when the operation rate is 130%, the lowest temperature at which the current coke quality can be maintained is set to 1210 ° C., but the reference temperature is raised. It can be seen that the tar yield is decreased and the gas generation amount is increased. That is, the reference temperature suitable for the tar demand will be given. Here, even when the volatile matter and water content of the coking coal change, the reference temperature corresponding to the demand amount of tar is given in the same manner, and by setting the given reference temperature, the effective use of tar In terms of, a great effect can be obtained.

From the viewpoint of accelerating the thermal decomposition of tar, means for applying heat to the upper void portion of the carbonization chamber is conceivable, and the method of applying the heat is the same as heating in the combustion chamber. There is a means for giving heat from the above, that is, a means for raising the temperature of the upper part of the combustion chamber, or a means for introducing air into the upper void portion of the carbonization chamber to burn the generated gas.

When the temperature in the upper void of the carbonization chamber is increased by 200 ° C. as an example by such a method, the calculation using the above simulation model reduces the tar yield by 0.1%, Moreover, the gas generation amount increases by 1.5 Nm ³ / t. In this way, the production yield of tar can be easily controlled.

Similarly, as a furnace constituent part capable of promoting thermal decomposition of tar, a recovery pipe for recovering gas generated in the coke furnace and a rising pipe part as a connecting portion with the furnace are provided. Yes, the outer circumference of the riser portion comes into contact with the atmosphere,
At present, the gas flowing in the pipe is cooled, but in the case of the current rising pipe, or in the case of the current riser pipe, the water in the coking coal is recovered immediately before it joins with the recovery pipe. Although it is cooled by the circulating water described above, there is a means for providing an external heating device and a cooling device after the riser pipe and heating with the external heating device instead of cooling the corresponding portion.

Also in this case, when the generated gas is heated by such a method, the calculation using the simulation model is carried out at 1400 ° C. and the retention time of 6
Under the condition of sec, the temperature in the upper void part of the carbonization chamber is set to 2
The same effect as when the temperature is increased by 00 ° C is obtained.

Further, when the generated tar is mixed with the raw coal and charged, the calculation using the simulation model is performed. As an example, the set reference temperature 1200 is set.
30% of the mixed tar when mixed 5% at ℃
Is coke, 25% is gas, and 10% is light oil. Here, the tar yield can be easily controlled by the mixing ratio and the set value of the reference temperature.

[0040]

As described above in detail, according to the yield control method for the by-product tar in the coke production according to the first to fifth aspects of the present invention, the coke oven is controlled corresponding to the balance of receiving and supplying tar. Changing each operating condition, that is, obtaining the reference temperature of the combustion chamber, the reference temperature of the upper void portion of the carbonization chamber, or the reference temperature in the rising pipe, and then controlling by any of these reference temperatures Due to
Since the generated tar is recovered as the tar itself or the tar is recovered as gas and coke, it is possible to specifically select the production yield of the tar and, eventually, meet the production target. It has an excellent feature that it can be used.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an outline of a reaction model applied to a yield control method of by-product tar in coke production of the present invention.

FIG. 2 is a structural explanatory view schematically showing an outline of an experimental furnace apparatus corresponding to the reaction model of the above.

FIG. 3 shows an experimental result and a calculation result using a reaction model with respect to a time-dependent change in gas generation rate (a) and a time-dependent change in gas composition (b) when the furnace temperature for secondary decomposition was kept constant. It is a graph.

[FIG. 4] Yield of tar as above (a) and 4700 kca
The actual value and the calculated value of the gas generation amount (b) per ton of coking coal converted to 1 / Nm ³ are shown, and the change over time in the gas generation rate when the furnace temperature for secondary decomposition is kept constant (a)
3 is a graph showing the experimental results and the calculation results using a reaction model for the change with time (b) in the gas composition.

FIG. 5 is a graph showing a change in tar yield (a) and a change in gas generation amount (b) when calculation is performed by changing the set reference temperature at each coke oven operating rate in the embodiment of the present invention. is there.

[Explanation of symbols]

11 Coking coal 12 Metaplast 13 Semi-coke 14 Coke 14a-14c Deposit coke 15a, 15b, 18 Gas 16, 16a, 16b Tar 17 Reaction water 31 Furnace apparatus 32 Carbonization chamber 33 Heating wall of carbonization chamber k _{1 to} k _{8 For} each reaction Reaction rate constant

Claims (5)

[Claims] 1. When the operating rate of the coke oven, the properties such as the water content and volatile content of the raw coal, and the required production amount of by-product tar are determined, the set reference temperature for coke firing is set in the coke oven carbonization chamber. A method of controlling the yield of by-product tar in coke production, wherein the value is calculated by a simulation of heat transfer and reaction of the product, and the production yield of the by-product tar is controlled by maintaining the set reference temperature. 2. When the operating rate of the coke oven, the properties of the raw coal such as water and volatile matter, and the required amount of by-product tar are determined, the temperature in the upper void portion of the coke oven carbonization chamber is set to
In order to obtain a value calculated by simulation relating to heat transfer and reaction in the carbonization chamber, the temperature in the upper void portion of the carbonization chamber is maintained at a reference temperature value corresponding to the calculated value, and by-product tar is produced at the reference temperature value. Control method for yield of by-product tar in coke production, characterized in that the production yield of the product is controlled. 3. The control method according to claim 2, wherein a required amount of air is introduced into the upper void portion of the carbonization chamber, and a part of gas and / or by-product tar generated during coke firing is combusted. And maintaining the temperature in the upper void portion at the reference temperature value by the combustion, the yield control method of by-product tar in coke production. 4. When the operating rate of the coke oven, the properties such as the water content and volatile content of the raw coal, and the required production amount of by-product tar are determined, the temperature inside the coke oven riser pipe is used to determine the temperature inside the coke oven carbonization chamber. In order to obtain the value calculated by the heat and reaction simulation, the temperature in the riser pipe is maintained from the outside by the reference temperature value corresponding to the calculated value, and the production yield of the by-product tar is maintained at the reference temperature value. Controlling the yield of by-product tar in the production of coke, which is characterized by controlling the temperature. 5. When the operating rate of the coke oven, the properties such as the water content and volatile content of the raw coal, and the required production amount of by-product tar are determined, the temperature inside the coke oven carbonization chamber is set to the heat transfer inside the carbonization chamber. In order to obtain a value calculated by a simulation related to the reaction, a part of the by-product tar generated during coke firing is mixed with the raw coal at a ratio calculated by the simulation and burned, and the temperature in the carbonization chamber is set to the above by the combustion. Maintain the reference temperature value corresponding to the calculated value,
A method for controlling the production yield of by-product tar in coke production, which comprises controlling the yield of by-product tar at the reference temperature value.