JPH1135943A - Method for controlling furnace pressure of coke oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling the furnace pressure of a cake oven capable of achieving a uniform furnace pressure in the furnace width direction. SOLUTION: A coke oven 10 whose furnace pressure is to be controlled comprises channels for supplying a fuel gas 24 and air 21 to each combustion chamber 12, horizontal flues 17 for collecting waste gas discharged from each combustion chamber 12 to centralized flues 14a, 14b provided at the front and rear sides of the oven and dampers 16a, 16b for passing the waste gas provided in the neighborhood of the centralized flues 14a, 14b at the both ends of the horizontal flues 17. In the method for controlling the furnace pressure, the waste gas discharge flow area formed by the degree of opening of the dampers 16a, 16b is adjusted in such a manner that the waste gas discharge flow velocity to be collected to the centralized flues 14a, 14b from each horizontal flue 17 retains the oven average waste gas discharge flow velocity as used in the previous control, and the degree of opening of each of the dampers 16a, 16b is determined depending on the waste gas discharge flow area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coke oven pressure control method for a coke oven in which a plurality of rows of carbonization chambers and combustion chambers are arranged.

[0002]

2. Description of the Related Art In general, a coke oven forms one oven by a pair of a carbonization chamber and a combustion chamber which are alternately arranged in a plurality of rows in the oven width direction. Usually, 50 to 100 ovens are gathered to form one oven. It constitutes a furnace group. The combustion chamber is adjacent to the carbonization chamber via a furnace wall (brick wall) and is divided into 20 to 30 small combustion chambers in the furnace length direction, and the bottom of each small combustion chamber communicates with the heat storage chamber. Fuel gas and air whose flow rates have been adjusted by the fuel gas cock and the air cock are preheated and supplied to the respective small combustion chambers in the respective preheating regenerative chambers, and the combustion thereof heats the carbonization chambers on both sides through the furnace wall. , Coal carbonization is performed. Exhaust gas generated in each of the small combustion chambers is drawn down to a heat recovery heat storage chamber, heat is recovered, discharged to a horizontal flue, collected in a flue and discharged to the atmosphere from a chimney. The heat storage chamber for preheating is referred to as “standing side” and the heat storage chamber for heat recovery is referred to as “pulling side”, and the standing side and the pulling side are alternately switched in a combustion cycle (a control cycle of 30 minutes).

[0003] In this type of coke oven, as shown in Steelmaking Research No. 325 previously issued by the present applicant, the flow rate of fuel gas and air supplied to the furnace group is controlled to set the average carbonization time of the furnace group to the target carbonization time. A flue for adjusting the pressure of the furnace to be kept for a certain period of time, and a flue for adjusting the suction pressure provided in the collective flue to suppress fluctuations in the pressure in the combustion chamber (hereinafter simply referred to as furnace pressure) due to fluctuations in the fuel gas flow rate. In general, the furnace core average furnace pressure control for controlling the opening degree of the damper is performed. By the way, in a coke oven, a large amount of coal is carbonized using many carbonization chambers.
It is desired that the carbonization time be substantially the same between the carbonization chambers, and the flow rates of fuel gas and air supplied to each combustion chamber are adjusted. The suppression of the fluctuation of the furnace pressure due to the fluctuation of the flow rate of the fuel gas supplied to each combustion chamber is performed by adjusting the opening of waist dampers (hereinafter simply referred to as dampers) provided at both ends of the horizontal flue. However, the adjustment requires a high level of experience and skill and is extremely difficult.
That is, the exhaust system of the exhaust gas generated in the combustion chamber is complicated as shown schematically in FIG. 3, and it is extremely difficult to control the furnace pressure. In FIG. 3, in the first half cycle of combustion (when the heat storage chamber (i) is on the pulling side), the exhaust gas generated in the combustion chamber (i) and the combustion chamber (i + 1) passes through a path shown by a solid line and is stored in the heat storage chamber (i). After the heat is recovered on each brick wall, it is discharged to the horizontal flue (i).

The latter half cycle of combustion (heat storage chamber (i-1),
(When (i + 1) is the pulling side), the combustion chamber (i-1),
The exhaust gas generated in (i) is drawn down to a heat storage chamber (i-1) via a path shown by a broken line, and after being recovered in heat, is discharged to a horizontal flue (i-1), and is discharged to a combustion chamber (i + 1), (i + 2). )
The exhaust gas generated in step (i +) passes through the path indicated by the broken line
After being withdrawn in 1) and heat recovery, horizontal flue (i +
It is discharged to 1). And horizontal flue (i-1),
Exhaust gas discharged in (i) and (i + 1) is collected in a collecting flue through dampers provided at both ends. In this way, the exhaust system of the exhaust gas generated in the combustion chamber is connected to two adjacent combustion chambers, and the adjustment of the damper opening in one horizontal flue affects the furnace pressure fluctuation of the two combustion chambers. Become. Therefore, accurate control of the furnace pressure is difficult unless the change in the furnace internal pressure due to the operation of the damper opening is grasped quantitatively. Therefore, a skilled worker has repeatedly adjusted the opening degree of the damper based on experience based on the flow rate of fuel gas supplied to each combustion chamber to obtain a uniform furnace pressure distribution in the furnace width direction. It is a fact.

[0005]

However, in the conventional method, a skilled worker is required, and the opening degree of the damper varies depending on the experience and skill of the worker. As a result, the furnace pressure in each combustion chamber is increased. The fluctuations in the furnace pressure caused damage to the furnace body and were far from optimal furnace operation. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coke oven pressure control method capable of achieving a uniform furnace pressure distribution in a furnace width direction.

[0006]

According to the present invention, there is provided a semiconductor device comprising:
The coke oven pressure control method of the described coke oven, a carbonization chamber charged with coal and carbonized, and a furnace group provided with a plurality of rows alternately in the furnace width direction of combustion chambers for heating the carbonization chamber from both sides, A fuel gas flow path and an air flow path for supplying fuel gas and air to the combustion chamber, respectively, and a horizontal flue for flowing exhaust gas discharged from each combustion chamber to a collective flue provided before and after the furnace. In a method for controlling the internal pressure of a coke oven having dampers respectively provided at the front and rear ends of each of the horizontal flue, the discharge flow rate of exhaust gas from each of the horizontal flues to the collecting flue is lower than that of the earlier. The opening of the damper is determined so as to maintain the average exhaust gas discharge flow rate of the furnace group used in the control. A method for controlling the pressure in a coke oven according to claim 2 is the method for controlling a pressure in a coke oven according to claim 1, wherein a discharge flow rate of the exhaust gas from the horizontal flue to the collecting flue is a flow rate of the fuel gas. , The flow rate of the combustion air, and the exhaust gas discharge and circulation area of the damper. According to a third aspect of the present invention, there is provided a coke oven internal pressure control method according to the first aspect, wherein the average exhaust gas discharge flow rate of the furnace group is determined by the furnace internal pressure of the combustion chamber and the collective flue. , And the exhaust gas flow rate coefficient α is a fixed constant, and the exhaust gas expansion correction coefficient ε is a fixed constant. The method for controlling the pressure in the coke oven according to claim 4 is the method for controlling the pressure in the coke oven according to claim 3, wherein the measurement of the pressure in the combustion chamber is performed in one or a small number of combustion chambers. A pressure gauge is arranged and determined by the measured value.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is an external view of a main part of a coke oven to which a coke oven pressure control method according to an embodiment of the present invention is applied, and FIG. 2 is a configuration diagram of a main part of a flow path of the coke oven. 3 is a schematic diagram of an exhaust system for exhaust gas generated in a combustion chamber of the coke oven, and FIG. 4 is a block diagram showing a structure of a furnace internal pressure control system in the furnace internal pressure control method of the coke oven.

In FIG. 1 and FIG. 2, a coke oven 10
The cross section is partially shown so that the internal structure of FIG. Referring to the drawings, the coking chamber 11 into which coal is charged and the combustion chamber 12 for heating the coking chamber 11 from both sides are alternately arranged in the Z-axis direction (furnace width direction). , Each of which is provided in large numbers. A heat storage chamber 13 is provided below the carbonization chamber 11. The heat storage chamber 13 guides the supplied fuel gas and air to the combustion chamber 12, and collects exhaust gas generated by combustion before and after the coke oven. Lead to flue 14a, 14b. Therefore, the heat storage chamber 13 through which the high-temperature exhaust gas passes is heated by the exhaust gas and accumulates heat, so that the fuel gas and the air guided to the combustion chamber 12 are preheated in the heat storage chamber 13 in advance, heated and easily burned. In this embodiment, the flow path through which the fuel gas and air pass (the fuel gas flow path and the air flow path) and the horizontal flue (sole flue portion) 17 through which the exhaust gas passes take a combustion cycle (a control cycle of 30 minutes). Can be switched alternately. The coal is charged into each of the coking chambers 11, and the coal whose carbonization has been completed, that is, the coke that has been carbonized, is extruded by a not-shown extruder into a furnace cover 15.
From the side (PS) and out of the furnace from the opposite side (CS).

Regarding the configuration of the main part of the flow path of the coke oven,
This will be described with reference to FIG. The flow rate of the air (AIR) 21 is adjusted by an air cock 22 on the rising side, and is supplied from the heat storage chamber 13 to the combustion chamber 12 through the switching cock 23, the horizontal pipe 18a, and the under jet pipe 19a. In addition, coke gas (CO
G) and blast furnace gas (BFG) mixed fuel gas (MG)
The flow rate of the fuel gas 24 is adjusted by a fuel gas cock 25, and is supplied from the heat storage chamber 13 to the combustion chamber 12 through the switching cock 26, the horizontal pipe 18g, and the under jet pipe 19g. The flow rates of the air supplied to the furnace group and the entire flow rate of the fuel gas are adjusted by flow controllers 27 and 28, respectively. These flow controllers 27 and 28 control the set flow rates (target flow rates) by a process computer (not shown) to adjust the flow rates. In addition, by providing a flow meter in the flow controllers 27 and 28 or in series with them,
The actual fuel gas flow rate and actual air flow rate may be measured.

The exhaust gas generated in the combustion chamber 12 is supplied to the heat storage chamber 1
3, dampers 16a, 16 provided on the furnace lid 15 side (PS) and the opposite side (CS) through the horizontal flue 17
The flow rate is distributed according to the exhaust gas discharge flow area ratio formed by the opening degree of b, and the exhaust gas is discharged to the collecting flues 14a and 14b through one of the dampers 16a and 16b. In addition,
A not-shown in-furnace pressure gauge is provided on the ceiling of the representative combustion chamber 12 of the furnace group (one or a plurality of furnace groups may be provided), and a draft pressure gauge is provided on the collecting flues 14a and 14b. I have. The collecting flues 14a and 14b are provided with a flue damper for adjusting the drawing pressure (not shown). A furnace pressure control system is provided for adjusting and suppressing the opening of the furnace. Actuators are connected to the dampers 16a and 16b, respectively, so that their opening degrees can be adjusted. These actuators have their set openings (target openings) controlled by a process computer (not shown), and adjust the respective damper openings.

A structure of a furnace pressure control system in a coke furnace pressure control method according to an embodiment of the present invention will be described with reference to FIG. A furnace pressure control system shown in FIG. 4 is constructed in the process computer, and the process computer corrects and controls the opening of each of the dampers 16a and 16b in accordance with the processing procedure described below every time the combustion cycle switching is completed. The numbers in the circles at the upper left of each block shown in FIG. 4 indicate the processing procedure described below.

(Procedure 1) The exhaust gas discharge / circulation area ST of CS and PS on the pulling side in the previous combustion cycle is calculated. S _{CS, i} = S _duct −S _dumper × COS (θ _{CS, i} ) S _{PS, i} = S _duct −S _dumper × COS (θ _{PS, i} ) (1) The PS damper openings θ _CS , θ _PS are converted into flow areas S _CS , S _PS , and ST _{, i} = S _{CS, i} + S _{PS, i} ... (2) i) Total exhaust gas discharge and distribution area S
Calculate T. Here, S _duct is the duct area, S _dumper
Is the damper area, and the subscript i is the number assigned to the horizontal flue. (Procedure 2) Based on the fuel gas flow rate and the air flow rate supplied to each combustion chamber in the previous combustion cycle, referring to FIG. 3, calculate the flow rate of exhaust gas collected in the collecting flue through the horizontal flue. QWG _{, i (k-1)} = QFG _{, i (k-1)} + QFG _{, i + 1 (k-1)} (3) where QWG _{, i} is a horizontal flue (i). The flow rate of the exhaust gas collected in the collecting flue through QFG _{, i} is the flow rate of the exhaust gas calculated by the flow rate of the fuel gas supplied to the combustion chamber (i) and the flow rate of the air, and the flow rate QFG _{, i + 1} is the combustion chamber (i + 1) Is an exhaust gas flow rate calculated from a fuel gas flow rate and an air flow rate supplied to the fuel cell, and k represents a combustion cycle.

(Procedure 3) The exhaust gas discharge velocity of each horizontal flue is calculated, and the average exhaust gas discharge velocity of the furnace group is obtained. The exhaust gas flow rate QWG _{, i} generated in the combustion chamber and collected in the collecting flue through the horizontal flue is QWG _{, i} = α × ε × ST _{, i} × [2 × (P _{top, i} −P _draft ) / ρ ] represented by ^0.5 ......... (4). Where α is the flow coefficient of exhaust gas, ε
Is the exhaust gas expansion correction coefficient, P _top is the pressure in the furnace of the combustion chamber,
P _draft represents the draft pressure of the collecting stack, and ρ represents the density of the exhaust gas. In order to keep the furnace pressure constant against fluctuations in the exhaust gas flow rate, that is, fluctuations in the fuel gas flow rate and the air flow rate supplied to the combustion chamber, the flow rate characteristics of the damper (flow rate coefficient α
And the expansion correction coefficient ε of the exhaust gas are sequentially estimated, and the results are used to calculate and determine the exhaust gas circulation area of the CS and the PS. However, it is extremely difficult to estimate the flow characteristics sequentially. Therefore, within the normal operating range of the coke oven, it is assumed that the fluctuations of the flow coefficient and the expansion correction coefficient of the exhaust gas are small (that is, constant), and VWG _{, i} = QWG _{, i} / ST _{, i} = α × ε × [2 × (P _{top, i} −P _draft ) / ρ] ^0.5 ... (5), the exhaust gas discharge velocity VWG collected from each horizontal flue to the collective flue is calculated, and the average exhaust gas discharge velocity VWG of the furnace group is calculated. _Ask for _ME .

(Procedure 4) Based on the fuel gas flow rate and the air flow rate supplied to each combustion chamber in the current combustion cycle, referring to FIG. 3, the flow rate of the exhaust gas collected in the collecting flue through the horizontal flue is calculated. I do. QWG _{, i-1 (k)} = QFG _{, i-1 (k)} + QFG _{, i (k)} QWG _{, i + 1 (k)} = QFG _{, i + 1 (k)} + QFG _{, i + 2 (k)} (6) (Procedure 5) In the current combustion cycle, the discharge flow velocity of the exhaust gas collected in the collecting flue through the horizontal flue is maintained at the average exhaust gas discharge velocity VWG _ME in the furnace group determined in Step 3. Calculate the total flue gas discharge and distribution area of each horizontal flue. ST _{, i-1} = QWG _{, i-1 (k)} / VWG _ME ST _{, i + 1} = QWG _{, i + 1 (k)} / VWG _ME (7)

(Step 6) Based on the total exhaust gas discharge and circulation area of each horizontal flue calculated in step 5, and the ratio of the CS and PS exhaust gas discharge and circulation areas used in the control up to the current combustion cycle, the current combustion cycle Is used to determine the flow area of each damper on the pulling side. S _{CS, i-1 (k)} = SR _{, i-1} × ST _{, i-1} / (1 + SR _{, i-1} ) _{SPS, i-1 (k)} = ST _{, i-1} / (1 + SR _{, i- 1} ) S _{CS, i + 1 (k)} = SR _{, i + 1} × ST _{, i + 1} / (1 + SR _{, i + 1} ) _{SPS, i + 1 (k)} = ST _{, i + 1} / (1 + SR _{, i + 1} ) (8) where SR is the ratio of the area of exhaust gas discharge and circulation of CS and PS used in the control up to the current combustion cycle. (Procedure 7) The flow area of each damper is converted into an opening and determined, and is output to an actuator for correcting the opening of the damper, thereby correcting the opening of the damper.

With the above-described control, C is controlled according to the fluctuation of the flow rate of the fuel gas and the flow rate of the air supplied to each combustion chamber.
By adjusting the opening degree of the S and PS dampers, the pressure distribution in the furnace in the furnace width direction can be made uniform. In the description of the present invention, it has been described that the opening degree of the dampers provided at both ends of each horizontal flue is corrected by automatic control. The adjustment may be performed by an operator.

[0017]

According to the method for controlling the internal pressure of a coke oven according to any one of claims 1 to 4, the discharge rate of the exhaust gas collected from each horizontal flue to the collecting flue is controlled by the furnace group used in the previous control. PS and CS to maintain the average exhaust gas discharge flow rate
The exhaust gas discharge circulation area formed by the opening degree of the damper is adjusted, and the opening degree of each damper is determined based on the exhaust gas discharge circulation area, so that the fuel gas flow rate supplied to each combustion chamber and CS and P according to air flow fluctuation
By adjusting the opening of the S damper, the pressure distribution in the furnace in the furnace width direction can be made uniform.

[Brief description of the drawings]

FIG. 1 is an external view of a main part of a coke oven to which a coke oven pressure control method according to an embodiment of the present invention is applied.

FIG. 2 is a configuration diagram of a main part of a flow channel of the coke oven.

FIG. 3 is a schematic diagram of an exhaust system of exhaust gas generated in a combustion chamber of the coke oven.

FIG. 4 is a block diagram showing a structure of a furnace pressure control system in the furnace pressure control method for the coke oven.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Coke oven 11 Carbonization room 12 Combustion room 13 Thermal storage room 14a Collecting flue 14b Collecting flue 15 Furnace lid 16a Damper 16b Damper 17 Sole flue (horizontal flue) 18a Horizontal tube 18g Horizontal tube 19a Under jet pipe 19g Under jet pipe Reference Signs List 21 air 22 air cock 23 switching cock 24 fuel gas 25 fuel gas cock 26 switching cock 27 flow controller 28 flow controller

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Keihachiro Tanaka 1-9-4 Nihonbashi Honcho, Chuo-ku, Tokyo Inside Nippon Steel Elex Co., Ltd.

Claims (4)

[Claims] 1. A furnace group provided with a plurality of carbonization chambers in which coal is charged and carbonized, and a plurality of combustion chambers for heating the carbonization chambers from both sides are alternately arranged in a furnace width direction, and fuel is provided in each of the combustion chambers. A fuel gas flow path and an air flow path for respectively supplying gas and air, horizontal flue for flowing exhaust gas discharged from each of the combustion chambers to a collective flue provided before and after a furnace, and each of the horizontal smoke A method for controlling the internal pressure of a coke oven having dampers provided at front and rear ends of a passage, wherein the discharge flow rate of exhaust gas from each of the horizontal flue to the collecting flue is controlled by the furnace used in the previous control. A method for controlling the internal pressure of a coke oven, wherein the opening degree of the damper is determined so as to maintain the average exhaust gas discharge flow velocity of the coke oven. 2. The exhaust gas discharge flow rate from the horizontal flue to the collective flue is calculated based on a flow rate of the fuel gas, a flow rate of combustion air, and an exhaust gas discharge flow area of the damper. 2. The method for controlling the internal pressure of a coke oven according to claim 1. 3. The average exhaust gas discharge flow rate of the furnace group is obtained by measuring the pressure in the furnace of the combustion chamber and the draft pressure of the flue gas, further setting a flow coefficient α of the exhaust gas as a fixed constant, and an expansion correction coefficient ε of the exhaust gas. 2. The method according to claim 1, wherein the constant is set as a fixed constant. 4. The method according to claim 3, wherein the furnace pressure in the combustion chamber is measured by arranging a furnace pressure gauge in one or a small number of combustion chambers and determining the measured pressure.