JP2013087129A - Method of managing combustion of coke oven, and flow distribution control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a method of managing combustion of a coke oven allowing accurately controlling the oven length direction flow distributions of fuel gas and air supplied to a combustion chamber (flue) of the coke oven through a sole flue, and to provide a flow distribution control device of fuel gas and air for the method.SOLUTION: The method is provided for operating a coke oven in which a plurality of combustion chambers each consisting of flues divided plurally in the oven length direction, and a plurality of carbonization chambers are alternately arranged in the oven width direction, for carbonizing coal in the carbonization chambers by burning the fuel gas supplied in each flue with air. The method of managing the coke oven includes: adjusting the flow at a sole flue inlet based on the oven length direction temperature distribution of the combustion chamber in addition to controlling the flows of fuel gas and air supplied to the sole flues to be constant; and controlling the oven length flow distributions of fuel gas and air flowing into each flue.

Description

  The present invention relates to a combustion management method for a coke oven for producing coke by dry distillation of coal and a flow distribution control device for fuel gas and air, and specifically, a temperature distribution in the furnace length direction (extrusion direction) of a combustion chamber. The present invention relates to a combustion management method for a coke oven that controls the flow rate, and a flow rate distribution control device that controls the flow rate distribution of fuel gas and air in the furnace length direction.

  The coke oven has a structure in which multiple carbonization chambers that charge raw coal and combustion chambers that burn fuel gas with air are alternately arranged in the furnace width direction. The fuel gas is combusted with air in the chamber, and the coal charged in the carbonization chamber is indirectly heated and dry-distilled through the furnace wall between the carbonization chamber and the combustion chamber by the combustion heat to produce coke. Yes.

  FIG. 1 is a cross-sectional view of a combustion chamber portion of a coke oven. The combustion chamber portion is divided into a combustion chamber, a heat storage chamber, and a sole flue from the top, and each combustion chamber is further divided into small chambers called flues of about 20 to 40 in the furnace length direction (extrusion direction). Combustion gas and air are supplied to the sole flue from each gas pipe disposed outside the coke oven, and then distributed to each flue.

The fuel gas used in the coke oven, calories 4000~5000kcal / Nm ³ of about COG ( "rich gas") and other by-product gas mixture caloric 1000~3000kcal / Nm ³ of about mix gas ( "poor Gas)), but generally, a poor gas which is advantageous in terms of cost is often used. When a rich gas is used, it is usually supplied directly from the lower part of the flue to each flue without passing through the sole flue. In addition, the air supply method includes a forced ventilation method that uses a fan or the like, and a natural ventilation method that uses a draft of exhaust gas for suction.

  By the way, in the coke oven, the temperature distribution in the furnace length direction (extrusion direction) in the combustion chamber is controlled within a predetermined target range in order to uniformly dry-coal the coal in the carbonization chamber and keep the quality of the coke as a product constant. For this purpose, the flow rate of the fuel gas and air supplied to each furnace in the furnace length direction constituting the combustion chamber is adjusted so that the temperature distribution in the furnace length direction of the combustion chamber is within the target range. It is important to control so that Conventionally, the adjustment of the flow rate distribution in the furnace length direction is performed by using an opening adjustment plate installed at the lower part of the combustion chamber when using rich gas as the fuel gas, and at the lower part of the heat storage chamber when using poor gas. This is done by adjusting the opening area of the gas flow path leading to the combustion chamber or the heat storage chamber, using the installed opening adjustment plate.

  In addition, in the operation of a coke oven, in order to control the temperature distribution in the furnace length direction in the combustion chamber within the target range, adjustment of the flow distribution of fuel gas and air in the furnace length direction can be performed freely during operation. is necessary. However, the method of adjusting the opening area of the gas flow path using the opening adjustment plate can be performed only when combustion is stopped (during non-operation) for work safety, so the flow distribution can be freely distributed during operation. I can't control it.

  As another technique for adjusting the flow rate distribution, for example, in Patent Document 1, the end flue on the end side in the furnace length direction of the combustion chamber of the coke oven is provided with air and fuel gas whose flow rate is adjusted by a flow rate adjusting valve. In addition, air and fuel gas whose flow rate is adjusted by an orifice are supplied to the inner side of the end flue, and the flow rate adjusting valve is used when switching between the low operating rate operation and the high operating rate operation of the coke oven. A technique for adjusting the flow rate of the end flue is disclosed.

  Further, in Patent Document 2, in a method for operating a coke oven having a fuel gas and air adjustment cock provided in a fuel flow path and two waist dampers provided at both ends of an exhaust gas flow path, an average dry distillation in the furnace for each furnace is disclosed. In order to keep the time at the target carbonization time and minimize the variation in the average carbonization time in the furnace in the furnace width direction, it is determined by adjusting the opening degree of the fuel gas and air adjusting cock provided in the fuel flow path In order to minimize the variation in dry distillation time in the furnace length direction in the furnace, the opening of the two waist dampers is adjusted and determined to optimize the combustion chamber temperature distribution in the furnace width direction and the furnace length direction. A technique is disclosed in which the average in-furnace time in each furnace is maintained at the target carbonization time, and the variation in the in-furnace length in the furnace is minimized.

JP 2008-195901 A JP-A-10-140161

  However, in the method of Patent Document 1, it is possible to adjust the fuel gas flow rate of the end flue provided with the flow rate adjusting valve, but it is difficult to adjust the flow rate of the other flue. Further, in the method of adjusting the flow rate with the adjusting cock described in Patent Document 2, the flow rate decreases when the adjusting cock is closed, and the flow rate increases when the adjusting cock is opened. It is difficult to adjust the temperature distribution in the furnace length direction due to large changes in the flow rate distribution.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to flow in the furnace length direction of fuel gas and air supplied to the combustion chamber (flue) of the coke oven via the sole flue. In addition to proposing a combustion management method for a coke oven that can control the distribution with high accuracy, it is an object of the present invention to provide a fuel gas and air flow rate distribution control device.

  The inventors have intensively studied to solve the above problems. As a result, the flow rate of the fuel gas and air supplied to each sole flue is controlled by a regulating valve provided in the piping for supplying combustion gas and air to each sole flue, and the opening area of each sole flue inlet By adjusting the flow rate of the combustion gas and air at the inlet of the sole flue by changing the flow rate, it was conceived that the flow distribution in the furnace length direction of the fuel gas and air flowing through each flue could be controlled, leading to the development of the present invention. .

  That is, the present invention comprises a plurality of combustion chambers made of flues divided in the furnace length direction and a plurality of carbonization chambers alternately arranged in the furnace width direction, and the fuel gas supplied into each fulu is air. In the coke oven operation method, which burns and carbonizes coal in the carbonization chamber, the flow rate of the fuel gas and air supplied to the sole flue is controlled to be constant, and the flow velocity at the sole flue inlet is adjusted to flow through each flue. We propose a combustion management method for coke ovens that controls the distribution of fuel gas and air flow in the furnace length direction.

  The combustion management method for a coke oven according to the present invention is characterized in that the sole flue inlet flow velocity is adjusted based on a furnace length direction temperature distribution of the combustion chamber.

  The present invention also includes a plurality of combustion chambers composed of flues divided into a plurality of furnace length directions and a plurality of carbonization chambers arranged alternately in the furnace width direction. A fuel gas and air flow rate distribution control device in a coke oven for burning and carbonizing coal in a carbonization chamber, the fuel gas piping and air piping supplying fuel gas and air to each combustion chamber, and supplied from the above piping A flow rate adjusting valve for controlling the flow rate of the fuel gas and air to be constant between the fuel flow and the sole flue that distributes the fuel gas and air to each flue, and the flow velocity of the fuel gas and air is adjusted at the inlet of the sole flue A flow rate distribution control device for a coke oven, characterized in that a flow rate adjusting mechanism is provided.

  The flow velocity adjusting mechanism in the flow rate distribution control device of the present invention comprises at least two plates, and adjusts the opening area of the sole flue inlet by changing its position.

  According to the present invention, even during operation of the coke oven, it becomes possible to control the flow rate distribution of the fuel gas and air flowing in each flue in the furnace length direction to a predetermined target range, so that in the furnace length direction of the combustion chamber The temperature distribution can be controlled within the target temperature range, and as a result, the coke quality can be made uniform and the fuel gas can be reduced.

It is a schematic diagram which shows the cross-sectional structure of a coke oven, and the flow of fuel gas and air. It is a figure explaining the combustion system of a coke oven. It is a figure explaining the influence of the sole flue cross-sectional area and the gas flow velocity which have on the furnace length direction flow rate distribution of the gas which flows into a flue. It is a figure explaining the influence of the gas flow velocity of the sole flue inlet which has on the furnace flow direction flow rate distribution of the gas which flows into a flue. It is a figure which shows an example of the flow volume distribution control apparatus which concerns on this invention. It is a figure which shows the temperature distribution before improvement in an Example, and after improvement. It is a figure which shows the gas quantity which flows into each flue before improvement in an Example, and after improvement.

  FIG. 2 shows a coke oven combustion system. The fuel gas and air to be supplied to the coke oven are installed in the flow rate adjusting valve arranged in the main pipe of each gas, and in the pipe branched from the main pipe and supplying the fuel gas and air to each sole flue. The flow rate is adjusted by the adjustment valve. That is, the flow rate adjusting valve provided in the main pipe adjusts the flow rate of gas flowing through the coke oven, and the adjusting valve provided in the pipe branched from the main pipe adjusts the flow rate of gas flowing through each sole flue. Is done. The fuel gas and air supplied to each sole flue are then heated to about 900 ° C. in the heat storage chamber and then distributed to each flue constituting the combustion chamber.

Here, the flow of gas distributed from the sole flue to each flue can be considered in the same way as the flow of the branch pipe, and the flow rate is influenced by the static pressure and pressure loss according to the Bernoulli theorem below. Receive.
P = p + q = p + 1/2 · ρv ² = constant (where P: total pressure, p: static pressure, q: dynamic pressure, ρ: fluid density, v: velocity along the streamline)

Therefore, when the cross-sectional area of the sole flue is constant (equal cross-sectional area) in the furnace length direction, the flow velocity of the gas in the sole flue gradually decreases from the inlet side due to gas distribution to each flue. Accordingly, since the static pressure is restored, the flow rate of the gas flowing through each flue is small on the sole flue inlet side as shown by a solid line in FIG.
In addition, when the gas flow rate in the sole flue is equal in the furnace length direction (equal flow velocity), the pressure loss from the upstream side is greater than the recovery of static pressure, so the flow rate of the gas flowing through each flue As shown by a broken line in FIG. 3, it increases on the sole flue inlet side and decreases with distance from the inlet.

Therefore, when the gas flow rate at the sole flue inlet is changed and the gas flow rate at the sole flue inlet is changed, the flow distribution in the furnace length direction of the gas flowing through each flue is examined. Is increased, the dynamic pressure increases and the static pressure decreases on the sole flue inlet side, but the flow rate decreases and the dynamic pressure decreases toward the center of the furnace length away from the inlet. Is recovered, and further, the pressure loss increases and the static pressure decreases. As a result, the gas flow rate distribution in the furnace length direction flowing through each sole flue is small at the inlet side and the tip side and large at the center as shown by the solid line in FIG.
On the other hand, when the flow velocity at the sole flue inlet is reduced, the static pressure at the sole flue inlet side is large, but the pressure loss increases and the static pressure decreases as the distance from the inlet increases. As shown by the broken line in FIG. 4, the gas flow distribution in the direction is larger on the entry side and becomes smaller as the distance from the entry side increases.
Thus, it can be seen that under conditions where the gas flow rate on the sole flue inlet side is constant, the gas flow rate distribution flowing through each sole flue in the furnace length direction can be controlled by adjusting the gas flow rate on the sole flue inlet side.

  However, as shown in FIG. 2, when adjusting the flow velocity of the gas flowing through each sole flue with the regulating valve installed in the pipe supplying fuel gas and air to each sole flue branched from the main pipe, Since the flow rate has a proportional relationship and the flow rate also changes at the same time, the flow rate distribution cannot be adjusted as described above.

  Therefore, as a result of studying a method for solving the above problems, the inventors have controlled the gas flow rate to be constant with an adjustment valve installed in a pipe for supplying fuel gas and air to each sole flue branched from the main pipe. Then, it is thought that it suffices to provide a mechanism for adjusting the gas flow velocity at the sole flue inlet (A portion shown in FIG. 1) to adjust the flow velocity of the sole flue inlet, The present invention has been developed.

  Here, as a simple example of the flow rate adjusting mechanism, as shown in FIG. 5, for example, as shown in FIG. 5, the sole flue inlet is composed of a pair of metal plates. Although the thing which made the opening area adjustable is mentioned, it is not limited to this example.

In order to apply the coke oven combustion management method of the present invention and control the gas flow rate distribution in the furnace length direction, it is necessary to measure the temperature distribution of each flue in the furnace length direction (deviation from the target temperature distribution). . The temperature of each flue can be easily measured, for example, by inserting a thermocouple or using a radiation thermometer from an inspection port installed at the top of the flue.
Then, the temperature distribution in the furnace length direction of each flue and the target temperature distribution are compared, and for example, the fuel gas and air to be supplied to the portion where the deviation from the target temperature is large, in the portion where the temperature is low On the other hand, the flow rate of the fuel gas and air to be supplied may be adjusted to a high temperature portion, for example.

  This is a real coke oven with a furnace length of 15m and a twin-fluid combustion chamber consisting of 20 flues. The temperature (flue temperature) at the top of each flue composing the combustion chamber is measured using a radiation thermometer. The result is shown by a broken line in FIG. From this result, it can be seen that this temperature distribution has a problem that the temperature is higher on the CS side than the target temperature, and the temperature is low in the center. Therefore, by adjusting the flow rate distribution control device of the present invention, the inlet flow rate of the fuel gas and air sole flue is changed from the flow rate distribution with a large PS side and CS side flow rate, as shown in FIG. The temperature distribution in the furnace length direction was improved as shown by the solid line in FIG. 6. From this, it was confirmed that the combustion management method of the present invention is effective.

Claims (4)

Combustion chambers composed of flues divided into a plurality of furnace lengths and carbonization chambers are alternately arranged in the furnace width direction, and the fuel gas supplied in each fulu is burned with air to ignite the inside of the carbonization chambers. In the method of operating a coke oven for carbonizing coal, the flow rate of the fuel gas and air supplied to the sole flue is controlled to be constant, the flow velocity at the sole flue inlet is adjusted, and the furnace for the fuel gas and air flowing through each flue A combustion management method for a coke oven, characterized by controlling a flow distribution in a long direction. 2. The coke oven combustion management method according to claim 1, wherein the sole flue inlet flow velocity is adjusted based on a furnace length direction temperature distribution of the combustion chamber. Combustion chambers composed of flues divided into a plurality of furnace lengths and carbonization chambers are alternately arranged in the furnace width direction, and the fuel gas supplied in each fulu is burned with air to ignite the inside of the carbonization chambers. A fuel gas and air flow distribution control device in a coke oven for carbonizing coal, a fuel gas pipe and an air pipe for supplying fuel gas and air to each combustion chamber, and a fuel gas and an air supplied from the pipe. A flow rate adjusting valve for controlling the flow rates of the fuel gas and air to be constant between the sole flue distributed to each flue, and a flow rate adjusting mechanism for adjusting the flow velocity of the fuel gas and air is provided at the inlet of the sole flue. A flow distribution control device for a coke oven characterized by 4. The coke oven flow distribution control device according to claim 3, wherein the flow velocity adjusting mechanism is composed of at least two plates, and adjusts the opening area of the sole flue inlet by changing its position.

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