JP6658411B2 - Diagnosis method of coke oven condition - Google Patents

Description

  The present invention relates to a method for diagnosing a furnace body condition that can diagnose a furnace body state of a coke oven without investigating the furnace body.

  The coke oven includes a carbonization chamber and a combustion chamber, and carbonizes coal charged in the carbonization chamber by heat transfer from the combustion chamber to produce coke. Coke is extruded from the carbonization chamber by an extruder and discharged out of the coke oven.

  As a condition for carbonizing coal, it is preferable that the interior of the carbonization chamber is in an oxygen-free state, and that the carbonization chamber has an airtight structure. The coke oven has a refractory structure, and the carbonization chamber and the combustion chamber are separated by a refractory such as a refractory brick. In the carbonization chamber, a large number of refractories are adhered with mortar or the like to maintain airtightness. The furnace lid is also isolated from outside air by a seal plate or the like.

  When air enters the chamber of the carbonization chamber, adverse effects such as burning of coal and combustion of coke oven gas (COG) generated by carbonization adversely affect carbonization of coal, and damage to refractories in the carbonization chamber. There are cases. In particular, when the airtightness of the coking chamber decreases due to expansion of the furnace body, joint cracking, and damage to the refractory due to aging or deterioration of the coke oven, damage to the refractory due to air entering the chamber of the coking chamber. There is a case where a vicious cycle is repeated, in which the amount of air infiltration is further increased.

  The intrusion of air into the coking chamber not only promotes refractory damage, but also affects the productivity of coke, such as delay in carbonization of coal and an increase in coke extrusion resistance. Therefore, at an appropriate timing, the airtightness of the carbonization chamber is restored by repairing the refractory constituting the carbonization chamber, repairing the furnace lid seal plate, and the like. However, in order to make such repairs, coke production must be stopped. Also, the repair requires a considerable amount of time, during which time coke cannot be produced.

  Further, a decrease in the airtightness of the carbonization chamber can be predicted by measuring the expansion of the furnace body. However, the expansion of the furnace cannot be measured frequently because the production of coke must be stopped.

  Therefore, it is necessary to diagnose the condition of the coke oven body by detecting a decrease in the airtightness of the coking chamber as quickly as possible without stopping the coke production so as not to affect the coke productivity. .

  As a method for detecting airtightness, there is a method of embedding an optical fiber sensor at a joint of a furnace port and measuring a temperature distribution around the furnace port (for example, Patent Document 1). According to this method, it is possible to detect a deteriorated portion of the joint by utilizing the fact that the temperature rises due to the combustion of the coke oven gas at the location where air has entered.

  In addition, by controlling the concentration of carbon monoxide or oxygen or the concentration of carbon monoxide and oxygen in the combustion exhaust gas between the heat storage chamber of the coke oven and the combustion exhaust gas switching valve, the furnace wall of the coke oven in the coke oven is controlled. And a method of detecting the presence or absence of damage (for example, Patent Document 2). This method detects incomplete combustion that occurs when the coke oven gas in the coking chamber leaks into the combustion chamber through the damaged part of the furnace wall from the change in the concentration of carbon monoxide and oxygen in the combustion exhaust gas component, and detects the incomplete combustion. Damage can be detected.

JP-A-6-158051 JP-A-11-5982

  However, the method described in Patent Literature 1 utilizes a phenomenon in which coke oven gas burns due to intrusion of air. Therefore, although it is possible to detect the intrusion of air into the portion where the optical fiber is laid, it is not possible to detect the air that enters from a portion other than the furnace port.

  Further, in the method described in Patent Document 2, changes in the concentration of carbon monoxide and oxygen are caused by imbalance in the flow rate of fuel gas supplied to the combustion chamber, blockage of a passage for supplying air for combustion, It can also occur due to factors other than damage to the furnace wall of the coking chamber, such as a decrease in airtightness of the furnace. Therefore, it is not possible to specify only a decrease in the airtightness of the carbonization chamber.

  The present invention has been made in view of the above-described problems, and has a function of monitoring coke oven gas by monitoring specific components in coke oven gas to determine whether or not air has entered the coking chamber due to deterioration of the coke oven. An object of the present invention is to provide a method for diagnosing a furnace body condition of a coke oven, which can detect deterioration of the furnace body state of the furnace at an early stage.

  In order to solve the above problems, according to an aspect of the present invention, a hydrogen cyanide concentration measuring a concentration of hydrogen cyanide contained in a coke oven gas generated by carbonizing coal in one or more carbonization chambers of a coke oven. A measurement step, a hydrogen cyanide concentration comparison step of comparing the concentration of hydrogen cyanide obtained in the hydrogen cyanide concentration measurement step with a reference concentration of hydrogen cyanide for judging a furnace body state of the coke oven, and a result of the hydrogen cyanide concentration comparison step And a judging step of judging the airtightness of the coking chamber based on the above method.

  The determining step may include, in the hydrogen cyanide concentration comparing step, a step of determining that the airtightness of the carbonization chamber has been reduced when the concentration of the hydrogen cyanide is higher than the reference concentration by a predetermined ratio or more. it can.

  The method for diagnosing the furnace body condition of the coke oven comprises: an ammonia concentration measuring step of measuring the concentration of ammonia contained in the coke oven gas; and the ammonia concentration obtained in the ammonia concentration measuring step. An ammonia concentration comparing step of comparing with a reference concentration of ammonia for judging a state, wherein the judging step includes a step of judging airtightness of the carbonization chamber based on a result of the ammonia concentration comparing step. Can be included.

  The determining step may include, in the ammonia concentration comparing step, a step of determining that the airtightness of the carbonization chamber has been reduced when the ammonia concentration is lower than the reference concentration.

  The reference density may be a preset density.

  The reference concentration of hydrogen cyanide can be the concentration of hydrogen cyanide contained in the coke oven gas generated in one or more carbonization chambers different from the carbonization chamber in which the hydrogen cyanide concentration was measured in the hydrogen cyanide concentration measurement step. .

  The reference concentration of ammonia may be the concentration of ammonia contained in the coke oven gas generated in one or more carbonization chambers different from the carbonization chamber in which the concentration of ammonia was measured in the ammonia concentration measurement step. .

  The coke oven includes an exhaust pipe through which coke oven gas is discharged from one or more of the coking chambers, and in the hydrogen cyanide concentration measurement step, measures the concentration of hydrogen cyanide contained in the coke oven gas flowing through the discharge pipe. Steps may be included.

  The coke oven includes a plurality of the coking chambers, and the discharge pipe connects one collecting pipe in which the coke oven gas discharged from the plurality of the coking chambers gathers and the plurality of the coking chambers and the collecting pipe. Including a plurality of connecting pipes, the hydrogen cyanide concentration measuring step may include a step of measuring a concentration of hydrogen cyanide contained in a coke oven gas flowing at least one of the collecting pipe and the connecting pipe.

  The collecting pipe is connected to a collecting pipe in which coke oven gas flowing through the collecting pipe of each coke oven is further collected, and in the hydrogen cyanide concentration measuring step, the collecting pipe, the connecting pipe, and the collecting main pipe are connected. The method may include a step of measuring the concentration of hydrogen cyanide contained in the coke oven gas flowing through at least one of them.

  The hydrogen cyanide concentration measuring step is a step of measuring the concentration of hydrogen cyanide contained in the coke oven gas flowing through the collecting pipe, and the reference concentration is the collecting pipe whose hydrogen cyanide concentration was measured in the hydrogen cyanide concentration measuring step. The concentration of hydrogen cyanide contained in the coke oven gas flowing through one or more collecting pipes may be different.

  As described above, according to the present invention, the state of the furnace body of the coke oven can be diagnosed without investigating the furnace body, and the deterioration of the state of the furnace body of the coke oven can be detected at an early stage.

It is a schematic diagram which shows the generated COG line from the coke oven in which the coke oven gas generated in the coke oven is refined and stored to the coke oven gas holder through the gas purification step. It is the schematic diagram which expanded the coke oven 2a and the discharge pipe 8a in the refinement line 1. It is a figure which shows the relationship between the kiln clogging frequency and the hydrogen cyanide concentration in coke oven gas.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the specification and the drawings, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted.

  The method for diagnosing a furnace body condition of a coke oven according to the embodiment includes a hydrogen cyanide concentration measuring step, a hydrogen cyanide concentration comparing step, and a determining step.

  First, the hydrogen cyanide concentration measuring step is a step of measuring the concentration of hydrogen cyanide contained in the coke oven gas generated by carbonizing coal in one or more carbonization chambers of the coke oven. Since the concentration of hydrogen cyanide in the coke oven gas changes according to the airtightness of the carbonization chamber, the concentration of hydrogen cyanide is measured. Hereinafter, the details of the hydrogen cyanide concentration measurement step will be described.

  Here, dry distillation means that non-volatile solid organic matter is thermally decomposed by igniting heat in a state where air is shut off, and a product of the pyrolysis is divided into a volatile organic compound and a non-volatile substance. When coal corresponding to nonvolatile solid organic matter is carbonized in a coke oven, for example, the coal is charged into a carbonization chamber to be in an air-tight state to be in an oxygen-free state, and the coal is strengthened by heat transfer from the combustion chamber. Decomposes by heating. By pyrolysis, coal is divided into coke oven gas, which corresponds to volatile organic compounds, and coke, which corresponds to non-volatile substances.

  Typically, coke oven gas is composed of about 50% by volume of hydrogen, about 30% by volume of methane, and about 20% by volume of impurities. Examples of impurities include hydrogen sulfide, ammonia, hydrogen cyanide, light oils such as benzene, naphthalene, and tar mist. Table 1 shows an example of the concentration of impurities contained in the coke oven gas.

As shown in Table 1, the concentration of hydrogen cyanide (HCN) contained in the coke oven gas, 1 to 2 g / Nm ³ are normal value. If the airtightness of the carbonization chamber is maintained during the carbonization and the oxygen-free state of the carbonization chamber is ensured, the concentration of hydrogen cyanide should be a normal value regardless of the difference in raw materials such as coal import sources and lots. Is within the range.

  However, if the airtightness of the coking chamber during carbonization is reduced due to damage to the refractory bricks on the wall surface of the coking chamber or aging of the coke oven due to cracks in the mortar, air may enter the coking chamber. In this case, during the carbonization, oxygen in the air and methane in the coke oven gas react with ammonia, and hydrogen cyanide is generated by an ammoxidation reaction represented by the following formula (1).

  When hydrogen cyanide is generated by the ammoxidation reaction, the concentration of hydrogen cyanide in the coke oven gas increases accordingly. Therefore, the concentration of hydrogen cyanide in the coke oven gas is a measure for knowing the airtight state of the coking chamber.

  The concentration of hydrogen cyanide in the coke oven gas can be measured by a general method for analyzing gas components. For example, it can be measured by a gas chromatography method or the like using a method for analyzing hydrogen cyanide in exhaust gas (JIS K 0109). In the embodiment, a part of coke oven gas generated by carbonizing coal in one or more carbonization chambers can be fractionated to measure the concentration of hydrogen cyanide.

  Next, the hydrogen cyanide concentration comparing step is a step of comparing the hydrogen cyanide concentration obtained in the hydrogen cyanide concentration measuring step with a reference concentration of hydrogen cyanide for judging the condition of the coke oven. By the hydrogen cyanide concentration measuring step, an actually measured value of the concentration of hydrogen cyanide in the coke oven gas is obtained. This measured value is compared with the reference density. The reference concentration is a concentration for judging the state of the furnace body of the coke oven, and the concentration of hydrogen cyanide when the state of the furnace body is normal can be used as the reference concentration.

The reference concentration is not particularly limited as long as the concentration indicates that the furnace body state is normal. For example, a preset density can be used as the reference density. Specifically, the reference concentration can be arbitrarily set in advance from a range of 1 to 2 g / Nm ³ which is a normal value of the concentration of hydrogen cyanide. In addition, when the coke oven is operating normally, the actual measured values of the concentration of hydrogen cyanide in the coke oven gas are measured in advance, and the upper limit of these measured values, the monthly average value, the annual average value, and the like are determined. For example, the reference density can be set in advance by using past measured values as a guide. The previously measured values are measured values in the past in the same coking chamber, past measured values in other coking chambers, past measured values in a plurality of coking chambers including or not including the same coking chamber, Past actual measured values of the entire coke oven, past actual measured values of other coke ovens, and the like can be used alone or in an appropriate combination.

  As the reference concentration, the preset concentration can be used as a reference concentration, and one or a plurality of carbonization chambers (“other carbonization chambers” different from the carbonization chamber in which the hydrogen cyanide concentration was measured in the hydrogen cyanide concentration measurement step) can be used. The concentration may be the concentration of hydrogen cyanide contained in the coke oven gas generated in the "coking chamber". In this case, the reference concentration may be an actual measured value of the concentration of hydrogen cyanide in another carbonization chamber, instead of a preset concentration. For example, when there is no difference between coal import sources and lots, and the same type of coal is carbonized, the concentration of hydrogen cyanide in another carbonization chamber can be used as the reference concentration for the concentration of hydrogen cyanide in a specific carbonization chamber. . As such a reference concentration, for example, it is possible to use the same measured value of the concentration of hydrogen cyanide obtained by carbonizing the same type of coal in another carbonization chamber, simultaneously with the carbonization in the hydrogen cyanide concentration measurement step, before or after the carbonization. it can. In addition, as the measured values of the other coking chambers, the measured values in one coking chamber, the measured values in a plurality of coking chambers, the measured values of the coke oven as a whole, and the measured values in another coke oven, etc., alone or appropriately. They can be combined. Then, such an actually measured value can be used as a reference density.

  Then, the determination step is a step of determining the airtightness of the carbonization chamber based on the result of the hydrogen cyanide concentration comparison step. For example, it is possible to compare a measured value of the hydrogen cyanide concentration obtained in the hydrogen cyanide concentration measuring step with the reference concentration, calculate a difference in the concentration, and determine the airtightness based on the obtained difference in the concentration. it can. For example, when the measured value is lower than or equal to the reference concentration, it can be determined that the airtightness of the carbonization chamber in which the hydrogen cyanide concentration measurement step has been performed is not abnormal.

  The determining step may include, in the hydrogen cyanide concentration comparing step, a step of determining that the airtightness of the carbonization chamber has been reduced when the concentration of the hydrogen cyanide is higher than the reference concentration by a predetermined ratio or more. it can. If the measured value obtained in the hydrogen cyanide concentration measurement step is higher than the reference concentration by a predetermined ratio or more, for example, if it is higher than the range of error or variation, air is supplied to the carbonization chamber where the measured value is obtained. It is considered that the concentration of hydrogen cyanide increased due to the intrusion and the generation of hydrogen cyanide by the reaction of the above formula (1). Therefore, it can be determined that the airtightness of the carbonization chamber is reduced.

When the ratio is higher than the predetermined ratio, the ratio of the measured value to the reference concentration for determining that the airtightness of the carbonization chamber has decreased is, for example, 1.3 times the reference concentration when the reference concentration is a preset concentration. Or higher. In consideration of errors and variations that can be tolerated from the reference concentration, if the concentration is 1.5 times or more the reference concentration, it can be determined that the airtightness of the carbonization chamber has definitely decreased. As an example, when the reference concentration is 2 g / Nm ³ which is the normal value of the hydrogen cyanide concentration, and when it is determined that the airtightness has decreased when the measured value is 1.3 times or more the reference concentration, When the measured value is 2.6 g / Nm ³ or more, it can be determined that the airtightness has decreased. Also, if the measured value is airtight when more than 1.5 times the reference density is determined that decreases, when the measured value became 3.0 g / Nm ³ or more, airtightness decreases with You can judge. The upper limit of the predetermined ratio is not particularly limited because the amount of hydrogen cyanide generated by the reaction of the above formula (1) increases in accordance with the amount of air entering the carbonization chamber. However, when the above-mentioned predetermined ratio is 2.0 times or more of the reference concentration, it can be said that the state of the furnace body is clearly deteriorated because the amount of air entering the carbonization chamber is too large.

Also, the reference concentration is not a preset concentration, but hydrogen cyanide contained in the coke oven gas generated in one or more carbonization chambers different from the carbonization chamber in which the hydrogen cyanide concentration was measured in the hydrogen cyanide concentration measurement step. Is the same as the case of the reference density. In other words, when the ratio is higher than the predetermined ratio, the ratio of the actually measured value that determines that the airtightness of the carbonization chamber has decreased to the reference concentration may be 1.3 times or more the reference concentration. In consideration of errors and variations that can be tolerated from the reference concentration, if the concentration is 1.5 times or more the reference concentration, it can be determined that the airtightness of the carbonization chamber has definitely decreased. As an example, when the concentration (reference concentration) of hydrogen cyanide contained in coke oven gas generated in another coking chamber is 2 g / Nm ³ and the measured value is 1.3 times or more the reference concentration, When it is determined that the airtightness has decreased, it can be determined that the airtightness has decreased when the measured value is 2.6 g / Nm ³ or more. Also, if the measured value is airtight when more than 1.5 times the reference density is determined that decreases, when the measured value became 3.0 g / Nm ³ or more, airtightness decreases with You can judge. The upper limit of the predetermined ratio is not particularly limited because the amount of hydrogen cyanide generated by the reaction of the above formula (1) increases in accordance with the amount of air entering the carbonization chamber. However, when the above-mentioned predetermined ratio is 2.0 times or more of the reference concentration, it can be said that the state of the furnace body is clearly deteriorated because the amount of air entering the carbonization chamber is too large.

  The method of diagnosing the furnace body condition of the coke oven of the embodiment is to measure the concentration of hydrogen cyanide contained in the coke oven gas to be a guide of the furnace body state, and further add the ammonia concentration contained in the coke oven gas to the guide. Can be.

As shown in the above formula (1), ammonia contained in the coke oven gas reacts with oxygen contained in the air that has entered the coking chamber to generate hydrogen cyanide. Here, the same mole of ammonia is consumed to generate hydrogen cyanide (Equation (1)). The concentration of ammonia contained in the coke oven gas, 6-10 g / Nm ³ are normal value. If the airtightness of the carbonization chamber is maintained during the dry distillation and the oxygen-free state of the carbonization chamber is ensured, the ammonia concentration should be the normal value regardless of the difference in raw materials such as coal import sources and lots. Is within the range. Thus, ammonia is related to the ammoxidation reaction produced by hydrogen cyanide and has a normal concentration. Therefore, when the concentration of ammonia is used as a guide, the same concentration measuring step, concentration comparing step, and determining step as in the case of hydrogen cyanide can be used.

  That is, the method for diagnosing the furnace body condition of the coke oven of the embodiment includes an ammonia concentration measurement step of measuring the concentration of ammonia contained in the coke oven gas, and the ammonia concentration obtained in the ammonia concentration measurement step. An ammonia concentration comparing step of comparing with a reference concentration of ammonia for judging a furnace body state of the furnace. In this case, the determination step includes a step of determining the airtightness of the carbonization chamber based on the result of the ammonia concentration comparison step.

  The concentration of ammonia in the coke oven gas can be measured by a general method for analyzing gas components. For example, it can be measured by an ion chromatographic method or the like using a method for analyzing ammonia in exhaust gas (JIS K 0099). In the embodiment, a part of a coke oven gas generated by carbonizing coal in one or a plurality of carbonization chambers can be fractionated and the concentration of ammonia can be measured.

In the method of diagnosing a coke oven body condition of the embodiment, the reference concentration of ammonia may be a preset concentration. Specifically, 6 to 10 g / Nm ³ , which is a normal value of the concentration of ammonia, can be preset as a reference concentration. In addition, when the coke oven is operating normally, the measured values of the ammonia concentration in the coke oven gas are measured in advance, and the upper limit of these measured values, the monthly average value, the annual average value, and the like are determined. For example, the reference density can be set in advance by using past measured values as a guide. The previously measured values are measured values in the past in the same coking chamber, past measured values in other coking chambers, past measured values in a plurality of coking chambers including or not including the same coking chamber, Past actual measured values of the entire coke oven, past actual measured values of other coke ovens, and the like can be used alone or in an appropriate combination.

  In addition, in the case of ammonia, the reference concentration can be the preset concentration, and one or more carbonization chambers different from the carbonization chamber in which the ammonia concentration was measured in the ammonia concentration measurement step ( The concentration may be the concentration of ammonia contained in the coke oven gas generated in "other carbonization chamber". Instead of a preset concentration, an actual measured value of the concentration of ammonia in another carbonization chamber or the like may correspond. For example, when there is no difference between coal import sources and lots, and the same type of coal is carbonized, the concentration of ammonia in a specific coking chamber can be used as the reference concentration for the concentration of ammonia in a specific coking chamber. . As such a reference concentration, for example, a measured value of the concentration of ammonia obtained by carbonizing the same type of coal in another carbonization chamber in the past, simultaneously, or later can be used. In addition, a measured value in a single coking chamber, a measured value in a plurality of coking chambers, a measured value as a whole coke oven, and a measured value in another coke oven, etc., alone or in an appropriate combination, are defined as a reference concentration. be able to.

  In the case where the method for diagnosing the furnace body condition of the coke oven of the embodiment includes the ammonia concentration measuring step and the ammonia concentration comparing step, the determining step may include, in the ammonia concentration comparing step, the ammonia concentration being equal to the reference concentration. If it is lower than the above, a step of determining that the airtightness of the carbonization chamber has decreased may be included. If the measured value obtained in the ammonia concentration measurement step is higher than the reference concentration by a predetermined ratio or more, for example, if it is higher than the range of error or variation, air is supplied to the carbonization chamber where the measured value is obtained. It is considered that the ammonia concentration was lowered due to the penetration and the consumption of ammonia by the reaction of the above formula (1). Therefore, it can be determined that the airtightness of the carbonization chamber has been reduced.

Examples of the case where the concentration of ammonia is lower than the reference concentration include a case where the reference concentration is lower than the reference concentration when the reference concentration is a preset concentration. The reference concentration of hydrogen cyanide in the case of a 2 g / Nm ^3, if the measured value is 3.0 g / Nm ³ according to the hydrogen cyanide concentration measuring step, the hydrogen cyanide is 1 g / Nm ³ by the reaction of formula (1) Becomes When hydrogen cyanide is generated, the same mole of ammonia is consumed (Equation (1)). Therefore, when hydrogen cyanide (molecular weight 27) is produced at 1 g (0.037 mol) / Nm ³ by the reaction of the above equation (1), , 0.63 g (0.037 mol) / Nm ³ of ammonia (molecular weight 17) are consumed. In this case, if the reference concentration in ammonia is 6 g / Nm ³ which is a normal value (Table 1), the concentration of hydrogen cyanide is increased by 1 g / Nm ³ by the reaction of the above formula (1), and the concentration of ammonia is 6 g / Nm ^3. 0.63g / Nm ³ is less than Nm ^3. As described above, since the concentration of ammonia decreases in relation to the ammoxidation reaction generated by hydrogen cyanide, it can be used to determine the airtightness of the carbonization chamber together with the concentration of hydrogen cyanide to diagnose the state of the furnace body. .

Further, the reference concentration is not a preset concentration, but the ammonia contained in the coke oven gas generated in one or more carbonization chambers different from the carbonization chamber in which the ammonia concentration was measured in the ammonia concentration measurement step. The case where the ammonia concentration is lower than the reference concentration is the same as the case of the above reference concentration. That is, when 1 g / Nm ³ of hydrogen cyanide is generated by the reaction of the above formula (1), the concentration of ammonia becomes 0.63 g / Nm ³ lower than the reference concentration.

  In the method for diagnosing a furnace body condition of a coke oven of the embodiment, the coke oven may include an exhaust pipe through which coke oven gas is exhausted from one or a plurality of the coking chambers. In this case, the hydrogen cyanide concentration measuring step may include a step of measuring the concentration of hydrogen cyanide contained in the coke oven gas flowing through the discharge pipe. The carbonization chamber is a chamber for carbonizing coal, and it is sometimes difficult to sample the generated coke oven gas due to high airtightness. On the other hand, sampling the coke oven gas from the discharge pipe after the coke oven gas is discharged from the coking chamber to the discharge pipe is easier than sampling in the coking chamber. Therefore, when the coke oven is provided with a discharge pipe, the coke oven gas flowing through the discharge pipe is sampled, and the concentration of hydrogen cyanide contained in the gas can be measured. Then, the concentration of hydrogen cyanide thus obtained is compared with, for example, a preset reference concentration to determine the airtightness of the carbonization chamber.

  In the case where the coke oven includes a plurality of the coking chambers, the discharge pipe may include one collecting pipe in which coke oven gas discharged from the plurality of the coking chambers is collected, and a plurality of the coking chambers and the collecting pipe. May be included. In this case, the hydrogen cyanide concentration measuring step may include a step of measuring the concentration of hydrogen cyanide contained in the coke oven gas flowing through at least one of the collecting pipe and the connecting pipe. The collecting pipe includes, for example, an air collecting main pipe (dry main) in which coke oven gas discharged from dozens of kiln carbonization chambers is collected, a suction main in which coke oven gas in the furnace group is collected, and a suction main in the dry main. Offtake mains, etc., which are communication pipes to Examples of the connection pipe include a riser pipe that raises and collects a coke oven gas having a low specific gravity from a carbonization chamber, and a bend pipe that connects the riser pipe to the air collection main pipe.

  In the above case, the coke oven gas flowing through the collecting pipe or the connecting pipe is appropriately sampled, and the concentration of hydrogen cyanide contained in the gas can be measured. Then, the concentration of hydrogen cyanide thus obtained is compared with, for example, a preset reference concentration to determine the airtightness of the carbonization chamber. Alternatively, an actual measured value of the concentration of hydrogen cyanide in another carbonization chamber or the like may be used as a reference concentration instead of or in combination with the preset reference concentration.

  In the method of diagnosing a coke oven body condition of the embodiment, the collecting pipe may be connected to a collecting main pipe in which coke oven gas flowing through the collecting pipe of each coke oven further collects. In this case, the hydrogen cyanide concentration measuring step may include a step of measuring the concentration of hydrogen cyanide contained in the coke oven gas flowing in at least one of the collecting pipe, the connecting pipe, and the collecting main pipe. . Examples of the collecting main pipe include a COG main pipe that further collects a suction main where coke oven gas of a furnace group is collected and introduces the suction main into a coke oven gas purification line.

  When the collecting pipe is connected to the collecting main pipe, in addition to the collecting pipe and the connecting pipe, a coke oven gas flowing through the collecting main pipe is appropriately sampled, and the concentration of hydrogen cyanide contained in the gas is measured. be able to. Then, the airtightness of the carbonization chamber can be determined by appropriately comparing the hydrogen cyanide concentration obtained in this way with, for example, a preset reference concentration or an actual measurement value of the hydrogen cyanide concentration in another carbonization chamber. .

  When the collecting pipe is connected to the collecting main pipe, the hydrogen cyanide concentration measuring step may be a step of measuring the concentration of hydrogen cyanide contained in the coke oven gas flowing through the collecting pipe. In this case, the reference concentration may be a concentration of hydrogen cyanide contained in a coke oven gas flowing through one or more collecting pipes different from the collecting pipe in which the concentration of hydrogen cyanide is measured in the hydrogen cyanide concentration measuring step. it can. The coke oven gas flowing through the collecting pipe is a gas discharged from the entire coke oven provided with the collecting pipe. Therefore, by comparing the concentration of hydrogen cyanide between the coke oven gas flowing through a certain collecting pipe and the coke oven gas flowing through another collecting pipe, it is possible to make a diagnosis by comparing the furnace body states of the coke ovens.

  The method for diagnosing a furnace body condition of a coke oven of the embodiment is not limited to the steps described above, and may include other steps. For example, using a normal value of hydrogen cyanide concentration or a measured value in the past as a guide, a process of setting a reference concentration in advance and determining a reference concentration before the hydrogen cyanide concentration comparison process, and a process of charging coal when carbonizing coal. A step of correcting a difference in the concentration of the coke oven gas caused by the amount.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the accompanying drawings.

  First, FIG. 1 will be described. FIG. 1 is a schematic diagram showing a generated COG line from a coke oven in which coke oven gas generated in a coke oven is purified and stored to a coke oven gas holder through a gas purification process. The purification line 1 includes a furnace group 3 including coke ovens 2a and 2b, a gas cooling device 4, a discharge blower 5, a gas purification process 6, and a coke oven gas holder 7. In a plurality of carbonization chambers (not shown) provided in the coke ovens 2a and 2b, coke oven gas is generated by carbonizing coal. The generated coke oven gas is discharged from the carbonization chamber to discharge pipes 8a and 8b. In FIG. 1, the discharge pipe 8a collects riser pipes and bend pipes 9a (corresponding to connection pipes) extending from the respective carbonization chambers, and coke oven gas of the riser pipes and the bend pipes 9a in the carbonization chambers for dozens of kilns. The dry main 10a (corresponding to a collecting pipe), the offtake main 11a (corresponding to a collecting pipe) which is a communication pipe from the dry main 10a to the suction main 12a, and the suction main 12a (corresponding to the coke oven gas of the furnace group). (Corresponding to a collecting pipe). The same applies to the discharge pipe 8b. The coke oven gas flowing through the dry mains 10a and 10b is sent to the COG main 13 and is further collected. Next, the collected coke oven gas is liquefied to collect coal tar, naphthalene, moisture and the like in the gas cooling device 4 and collected, and the gas purification proceeds. The coke oven gas is stored in the coke oven gas holder 7 after desulfurization, deammonification, degassing, etc. of the coke oven gas in the gas purification step 6. The discharge blower 5 sucks the coke oven gas from the coking chamber and sends it to the coke oven gas holder 7 through the gas purification step 6, as indicated by the white arrow in FIG.

(Example of furnace body state diagnosis method)
Next, an example of a method of diagnosing the furnace body condition of the coke ovens 2a and 2b in the purification line 1 of FIG. 1 will be described. First, coke oven gas is sampled at a predetermined position A where the COG main pipe 13 connects the discharge blower 5 and the gas purification process 6, and the concentration of hydrogen cyanide contained in the gas is measured to obtain an actually measured value. (Hydrogen cyanide concentration measuring step). Then, the measured value of the concentration of hydrogen cyanide in the coke oven gas at the position A is measured in advance, and the monthly average value is set as a reference concentration, and compared with the measured value (hydrogen cyanide concentration comparing step). The airtightness of the carbonization chamber is determined based on the result of the comparison step (determination step). If the measured value is substantially equal to the reference concentration, there is no problem in the airtightness of the coking chamber, and it can be diagnosed that the furnace body state of the coke oven is normal.

  On the other hand, when the measured value is 1.3 times or more higher than the reference concentration, it is determined that the airtightness of the coking chamber in one of the coke ovens 2a and 2b is reduced, and the furnace body state is abnormal. Can be diagnosed. In this case, the second hydrogen cyanide concentration measurement step can be performed in order to identify the carbonized chamber having reduced airtightness. Specifically, the coke oven gas is sampled in the suction mains 12a and 12b, and the concentration of hydrogen cyanide contained in the gas is measured to obtain an actually measured value (hydrogen cyanide concentration measuring step). Then, the measured values measured in the suction mains 12a and 12b are compared with the reference concentration (hydrogen cyanide concentration comparing step). For example, the measured value in the suction main 12a is higher than the reference concentration by 1.3 times or more. When the value is substantially equal to the reference concentration, it can be determined that the airtightness of any one of the coking chambers of the coke oven 2a is reduced.

  Further, when it is determined that the airtightness of any one of the coking chambers of the coke oven 2a is reduced, the specification of the carbonized chamber having the reduced airtightness will be described. FIG. 2 is a schematic diagram in which the coke oven 2a and the discharge pipe 8a in the refining line 1 are enlarged.

  First, in the suction main 12a, a coke oven gas is sampled at a position B between the offtake mains 11a1 and 11a2, and the concentration of hydrogen cyanide contained in the gas is measured to obtain an actually measured value (hydrogen cyanide concentration measuring step). . Then, the measured value is compared with the reference concentration (hydrogen cyanide concentration comparing step). For example, when the measured value at the position B of the suction main 12a is substantially the same as the reference concentration, there is no abnormality in the hydrogen cyanide concentration of the coke oven gas flowing through the offtake main 11a2. Among the chambers 14a to 14f, it can be determined that there is no problem in the airtightness of the carbonization chambers 14d to 14f (determination step). On the other hand, since it can be determined that the hydrogen cyanide concentration of the coke oven gas flowing through the offtake main 11a1 is higher than the reference concentration, the airtightness of any of the carbonization chambers among the carbonization chambers 14a to 14c can be determined. It can be determined that the property has decreased (determination step). In the case where there is no abnormality in the hydrogen cyanide concentration of the coke oven gas flowing through the offtake main 11a2, the hydrogen cyanide concentration of the coke oven gas flowing through the offtake main 11a1 is measured and compared with the reference concentration. Sex can be determined (determination step).

  Next, the coke oven gas is sampled at the positions C to E of the riser pipe and the bend pipes 9a1 to 9a3, and the concentration of hydrogen cyanide contained in the gas is measured to obtain an actually measured value (hydrogen cyanide concentration measuring step). Then, these measured values are compared with a reference concentration (hydrogen cyanide concentration comparing step). For example, when the measured value at the position C is substantially the same as the reference concentration and the measured values at the positions D and E are 1.3 times or more higher than the reference concentration, there is no problem in the airtightness of the carbonization chamber 14a. It can be determined that the airtightness of the carbonization chambers 14b and 14c is reduced (determination step). In this way, the carbonized chamber with reduced airtightness can be specified without investigating the furnace body itself.

  Before sampling the coke oven gas at the positions C to E of the riser and bend pipes 9a1 to 9a3, the hydrogen cyanide concentration of the coke oven gas flowing through the dry main 10a1 can be measured and compared with the reference concentration. For example, at the position F of the dry main 10a1, the coke oven gas is sampled, and the concentration of hydrogen cyanide contained in the gas is measured to obtain an actually measured value (hydrogen cyanide concentration measuring step). The comparison can be performed (hydrogen cyanide concentration comparison step). Then, the airtightness of the carbonization chamber 14a can be determined (determination step).

  In the embodiment of the present invention, the sampling of the coke oven gas is not limited to the above-described example of the furnace body state diagnosis method. Or you can do it all at once.

  In the example of the furnace body state diagnosis method described above, the monthly average value of past measured values is described as the reference concentration, but the present invention is not limited to this. For example, comparing the hydrogen cyanide concentrations in the dry main 10a and the dry main 10b, comparing the hydrogen cyanide concentrations measured at the positions CH in the riser and the bend tube 9a, and comparing the offtake main 11b with the riser and the bend tube 9a1 By comparing the measured values of the hydrogen cyanide concentration at the respective positions of the discharge pipes 8a and 8b as appropriate, such as comparing the hydrogen cyanide concentration at the position C in the above, it is possible to identify the carbonized chamber with reduced airtightness.

[Confirmation of effect]
The effect of the present invention confirmed in an actual coke oven will be described. FIG. 3 is a diagram showing the relationship between the frequency of occurrence of furnace clogging and the concentration of hydrogen cyanide in coke oven gas. In the coke oven, the operation of carbonizing the coal charged into the coking chamber for a certain period of time, extruding the completed coke by opening the oven lid of the coking chamber, and extruding the coke out of the coking chamber by a coke extruder or the like is repeatedly performed. The coke oven is a brick structure and manages and repairs the brick structure to maintain airtightness. However, as the furnace body expansion of the coke oven progresses over time, gaps are generated in various portions of the brick structure, and the chance of air invasion from outside the coke oven increases. The intrusion of air also affects dry distillation, such as increasing the variation in the temperature of the furnace body during dry distillation, and as a result, it leads to production obstacles such as furnace clogging due to poor carbonization of coal. The clogging of the kiln not only reduces the operating efficiency of the coke oven, but also imposes a large load on the furnace body. That is, the clogging of the kiln causes wear, cracks, and punctures of the refractory bricks and the like constituting the walls of the coking chamber, and further air enters the coking chamber to further reduce airtightness. If the airtightness of the coking chamber decreases, air entering the coking chamber may promote damage to the refractory and further increase the amount of air infiltration, which may lead to a vicious cycle, shortening the life of the furnace body. Becomes Thus, the clogging of the kiln can be a specific phenomenon indicating a decrease in the airtightness of the carbonization chamber.

  FIG. 3 plots the number of occurrences of clogging in the kiln when the coke is extruded 10,000 times on the horizontal axis, and the concentration of hydrogen cyanide in the coke oven gas is plotted on the vertical axis. In a furnace with 400 carbonization chambers, if the operation of producing coke once a day in each carbonization chamber is performed for 25 days, 10,000 cokes will be extruded. During this operation, the concentration of hydrogen cyanide was measured by sampling the coke oven gas in the collecting main pipe.

From the results shown in FIG. 3, it can be seen that as the concentration of hydrogen cyanide increases, the number of occurrences of clogging in the kiln tends to increase. For example, when the reference concentration is set to 2.0 g / Nm ³ , the measured value indicating 2.6 g / Nm ³ or more, which is 1.3 times the reference concentration, is recognized when the number of occurrences of kiln clogging is about 15 times. From this result, it can be diagnosed that the wall surface of the carbonization chamber has irregularities and air has entered, and that the furnace body state is deteriorating.

  As described above, in the carbonized chamber in which the concentration of hydrogen cyanide was higher than the reference concentration and the number of occurrences of clogging in the kiln was increased, the unevenness of the wall was smoothed by thermal spray repair, mortar repair, etc., and the airtight state was restored. Thereafter, the operation was resumed, and the coke oven gas was sampled in the same manner to measure the concentration of hydrogen cyanide and the number of clogging of the kiln was measured. As a result, the concentration of hydrogen cyanide was almost the same as the reference concentration, and the number of clogging of the kiln was small. That is, it is clear that the furnace body condition diagnosis method of the present invention can determine the airtightness of the coking chamber and diagnose the furnace body condition.

  As described above, an example of the embodiment of the present invention has been described in detail with reference to the accompanying drawings, but the present invention is not limited to this example. It is apparent that those skilled in the art to which the present invention pertains can conceive various changes or modifications within the scope of the technical idea described in the claims. It is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Purification line 2a, 2b Coke oven 3 Furnace group 4 Gas cooling device 5 Discharge blower 6 Gas purification process 7 Coke oven gas holder 8a, 8b Discharge pipe 9a, 9a1-9a6, 9b Ascending pipe and bend pipe 10a, 10a1, 10a2, 10b Dry main 11a, 11a1, 11a2, 11b Offtake main 12a, 12b Suction main 13 COG main pipe 14a-14f Carbonization chamber

Claims (11)

A hydrogen cyanide concentration measurement step of measuring the concentration of hydrogen cyanide contained in a coke oven gas generated by carbonizing coal in one or more carbonization chambers of a coke oven;
A hydrogen cyanide concentration comparison step of comparing the concentration of hydrogen cyanide obtained in the hydrogen cyanide concentration measurement step with a reference concentration of hydrogen cyanide for judging a furnace body state of the coke oven;
A determining step of determining the airtightness of the coking chamber based on a result of the hydrogen cyanide concentration comparing step.   The determining step includes, in the hydrogen cyanide concentration comparing step, a step of determining that the airtightness of the carbonization chamber has been reduced when the concentration of the hydrogen cyanide is higher than the reference concentration by a predetermined ratio or more. Item 3. A method for diagnosing a furnace body condition of a coke oven according to Item 1. An ammonia concentration measuring step of measuring the concentration of ammonia contained in the coke oven gas,
An ammonia concentration comparison step of comparing the concentration of ammonia obtained in the ammonia concentration measurement step with a reference concentration of ammonia for determining a furnace body state of the coke oven,
The method for diagnosing a coke oven body condition according to claim 1 or 2, wherein the determining step includes a step of determining airtightness of the coking chamber based on a result of the ammonia concentration comparing step.   4. The method according to claim 3, wherein, in the ammonia concentration comparing step, when the concentration of the ammonia is lower than the reference concentration, the determining step includes a step of determining that the airtightness of the carbonization chamber is reduced. 5. Method for diagnosing the condition of the coke oven.   The method according to any one of claims 1 to 4, wherein the reference concentration is a concentration set in advance.   The reference concentration of the hydrogen cyanide is a concentration of hydrogen cyanide contained in a coke oven gas generated in one or more carbonization chambers different from the carbonization chamber in which the concentration of hydrogen cyanide is measured in the hydrogen cyanide concentration measurement step. The method for diagnosing a furnace body condition of a coke oven according to any one of claims 1 to 4.   The ammonia reference concentration is a concentration of ammonia contained in coke oven gas, which is generated in one or more carbonization chambers different from the carbonization chamber in which the ammonia concentration is measured in the ammonia concentration measurement step. 5. The method for diagnosing a furnace body condition of a coke oven according to 3 or 4. The coke oven includes an exhaust pipe through which coke oven gas is exhausted from one or more of the coking chambers,
The method of diagnosing a coke oven furnace body according to any one of claims 1 to 7, wherein the hydrogen cyanide concentration measuring step includes a step of measuring the concentration of hydrogen cyanide contained in the coke oven gas flowing through the discharge pipe. The coke oven includes a plurality of the carbonization chambers,
The discharge pipe includes one collecting pipe in which coke oven gas discharged from the plurality of coking chambers and a plurality of connecting pipes connecting the plurality of coking chambers and the collecting pipe,
The furnace body of the coke oven according to claim 8, wherein the hydrogen cyanide concentration measuring step includes a step of measuring a concentration of hydrogen cyanide contained in a coke oven gas flowing at least one of the collecting pipe and the connection pipe. Condition diagnosis method. The collecting pipe is connected to a collecting main pipe in which coke oven gas flowing through the collecting pipe of each coke oven is further collected,
The hydrogen cyanide concentration measuring step includes a step of measuring a concentration of hydrogen cyanide contained in a coke oven gas flowing through at least one of the collecting pipe, the connecting pipe, and the collecting main pipe, according to claim 9, wherein Diagnosis method of furnace body condition of coke oven. The hydrogen cyanide concentration measuring step is a step of measuring the concentration of hydrogen cyanide contained in the coke oven gas flowing through the collecting pipe,
The said reference density | concentration is the density | concentration of the hydrogen cyanide contained in the coke oven gas which flows through one or several collecting pipes different from the said collecting pipe which measured the density | concentration of hydrogen cyanide in the said hydrogen cyanide concentration measurement process, The claim | item 10. Method for diagnosing the condition of the coke oven.

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