JPH03265685A - Method for controlling temperature of each chamber of coke oven - Google Patents

Abstract

PURPOSE:To prevent the control temperature of an oven from hunting and to maintain the control temperature at a preset oven temperature by minimizing the delay time in the control temperature response to the change in a preset oven temperature pattern with time to thereby keep the control temperature at the preset oven temperature. CONSTITUTION:The control temperature of an oven is calculated from a detected oven temperature to obtain an error in the prior estimation of the control temperature of an oven, which is stored in a table of the error in the prior estimation of the control temperature of an oven. A preset oven temperature is anticipated from a preset oven temperature pattern to calculate the target temperature of an oven. An estimated value of the control temperature of an oven is calculated to give correction heat, and the correction is restricted by a high-low limiter. Heat supply is calculated for each chamber and converted into a gas flow rate for each chamber, and the flow rate is restricted by a high-low limiter. A fuel flow rate is obtained for each effectively adjusting cock, and the opening of the adjusting cock is calculated and established to control the fuel gas flow rate. The difference between the target temperature of an oven and the control temperature of an oven is obtained as deviation. If the deviation is above a limit value, an operator alarm is outputted, thus controlling the temperature of each chamber of a coke oven.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for controlling the furnace temperature of each furnace in a coke oven, and in particular, the temperature control method for each furnace in a coke oven is The present invention relates to a furnace temperature control method for each kiln in a programmed heating operation in which the amount of heat (fuel gas) supplied is changed according to a determined furnace temperature pattern of a carbonization chamber.

[Prior art] In a coke oven, the set furnace temperature pattern of the carbonization chamber for each period of the carbonization process is determined based on the firing time, the furnace temperature, and the charging line input such as the amount of coal charged and its moisture content. A program heating method has been proposed in which the amount of heat supplied is controlled using this as a target value.

``Coke Oven Heating Control Power 7'' described in JP-A No. 59-20379 and ``Coke Oven Fire-off Time and Oven Temperature Control Method'' described in JP-A-61-47791 are based on the above program. This is a method previously proposed by the applicant as one of the heating methods.

However, in this program heating method, as in the case of the conventional coke oven furnace group average furnace temperature control method, the furnace temperature of the combustion chamber is determined by the carbonization state of both side carbonization chambers (time elapsed from the time of coal charging). Alternatively, it varies depending on the difference between fuel gas combustion and withdrawal, and there is a large response delay between the fuel gas flow rate and the furnace temperature in the combustion chamber.Therefore, there is a specific method to realize a servo system with high disturbance suppression ability. has not yet been established.

[Problems to be Solved by the Invention] When performing the above program heating, the present invention predicts the set furnace temperature in the next control cycle and uses the predicted value of the state quantity of the furnace temperature process obtained by a predetermined mathematical model. By checking the settings of the fuel gas adjustment cock and controlling the setting value of the fuel gas adjustment cock, fluctuations in the fuel gas flow rate can be minimized.
This prevents hunting of the controlled furnace temperature and minimizes the response delay time of the controlled furnace temperature to changes over time in the set furnace temperature pattern.
The purpose is to provide a method for maintaining the controlled furnace temperature at a set furnace temperature.

[i! Means and Effects for Solving the Problem] That is, the present invention provides a coke oven operation in which a set oven temperature pattern of a carbonization chamber in a carbonization process is predetermined based on the operating conditions and charging line of the coke oven. At each changeover, the estimation of the amount of heat supplied to each kiln and the a priori prediction error of the control furnace temperature are calculated and recorded in the storage area of the current carbonization cycle, and then the control furnace temperature in the next control stage is calculated from the previous carbonization cycle in the storage area. The prediction is made from the amount of heat supplied corresponding to the current control stage, the a priori prediction error for the next control stage, and the current controlled furnace temperature, and the set furnace temperature for the next control stage is predicted from the set furnace temperature pattern. Next, determine the target furnace temperature value, calculate the correction amount of the supplied heat amount based on the difference from the predicted value of the controlled furnace temperature at the next control stage, and calculate the current value based on the supplied heat amount for each kiln at the current point of the previous carbonization cycle. Calculate the amount of heat supplied to each kiln, determine the set gas flow rate for each adjustment cock based on the currently requested amount of heat supplied to each kiln, and set the adjustment cock opening degree by estimating the cock opening degree from the fuel gas flow rate each time the fuel gas is switched. By controlling the set value of the fuel gas flow rate control system, the response delay time of the controlled furnace temperature to changes over time in the set furnace temperature pattern is minimized, the controlled furnace temperature is maintained at the set furnace temperature, and the target furnace temperature is maintained. A method for controlling the furnace temperature of each furnace in a coke oven, characterized in that the difference between the control furnace temperature value and the control furnace temperature value is used as a control deviation, and when the deviation value exceeds a certain amount, an alarm is output to an operator to inform the operator that there is an abnormality. It is.

In performing the above-mentioned furnace temperature control for each kiln, the moving average value of the past atmospheric temperature of the combustion chamber - combustion cycle time is calculated,
In order to further minimize the effects of switching the heat storage chamber, temporal and spatial smoothing is performed to minimize fluctuations in the fuel gas flow rate, prevent hunting in the controlled furnace temperature, and set the controlled furnace temperature. This is a method for controlling the furnace temperature of each furnace in a coke oven, which is characterized by maintaining the furnace temperature at a constant temperature.

The present invention will be explained in detail below. FIG. 1 is a diagram showing an example of a control configuration of a furnace temperature control system for each oven of a coke oven according to the present invention.

The setting furnace temperature pattern of the carbonization chamber for each hour of the carbonization process is determined based on charging specifications such as fire-off time, kiln outlet temperature, amount of charged coal and its moisture content, and this is used as a target value in the present invention. By using the furnace temperature control method for each kiln in accordance with this method, the fuel gas flow rate f! IJfa
do l.

The method of determining this set furnace temperature is described in the above-mentioned Japanese Patent Application Laid-Open No. 59-203.
The method described in No. 79 and JP-A-61-47791 can be used.

FIG. 2 is a simplified diagram of a coke oven, and the carbonization chamber A, combustion chamber B, heat storage chamber C1, and adjustment cock D are numbered for the sake of explanation.

First, extract the effective adjustment cock (according to even or odd number of combustion gases) during the previous switching cycle, and calculate the flow rate ratio P using the following formula from the opening degree φ of the opening detector installed for each adjustment cock. P (i)-a φ' (i)+bφ3(
i) + cφ ” (i) + dφ (i) ◆e (1) where a, b, c, d, e: Model constants Next, calculate the flow rate F for the maximum adjustment cock opening using the following formula, F = X F (2)
Here, F: Average flow rate of the reactor group The fuel gas flow rate V corresponding to the individual adjustment cock opening degree is calculated using the following formula: V (]) = P (i) x F
(3) If the fuel gas is an odd number, the effective adjustment cock (
Calculate the amount of heat q supplied to the 11th place (even number adjustment cock) using the following formula q (i) = q cat x V (i)
(4) where qcal: fuel gas calorific value i: 01, 2, 4. ... Calculate the amount of heat QM for even numbered kilns using the following formula: QM (i
) −q (i) (s) where i: 2, 4, 6. ... Calculate the amount of heat QM for odd numbered kilns using the following formula Q M (
i) = 0.5x (q (i-1) +q (il
l)) (6) where i: 3, 5, 7. ... Calculate the amount of heat QM for the end kiln using the following formula Q M (1)
= Q (01) +0.5・q (2)
(7) Q M (n) = Q (On) +
0.5・q (n-1) (8) Next, when the combustion gas is even numbered, calculate the amount of heat q supplied to each effective adjustment cock (odd numbered adjustment cock) using the following formula: q (i ) = qcal xV(i)
(9) Here, i: 1, 3, 5. ... Calculate the amount of heat QM for the odd numbered kiln using the following formula.QM
(f) = q (i) (1
0) where i: 1, 3, 5. −... Calculate the amount of heat QM for even-numbered kilns using the following formula, and calculate QM
(i) = 0.5x (q (i-1)+q (il
l)) (11) where i: 2, 4, 6.・
...The total number of stages KCNT for furnace temperature control in this carbonization cycle is calculated using the following formula: K CN T = 2 x G CT r
(12) Here, GCTr: target carbonization time, furnace temperature control for each kiln, number of times of control after startup NTFC is updated, and when the following equation holds, NTFC(i)=KCNT.

NTFC(i)>KCNT (13)
Set the number of stages KN for the next control stage in the previous carbonization cycle using the following formula: KN(K) = KCNT (14) Here, if the number of control stages in one carbonization cycle has not been reached, set K
N(K)-1 Next, the supplied heat quantity table Q, which is a storage area for all kilns, and the control furnace temperature a priori prediction error table θC3err are updated by the total number of stages KCNT for furnace temperature control, and the supplied heat quantity QM for each kiln is updated. of,
Set to storage area supply heat amount table Q.

Next, the a priori predicted value of the controlled furnace temperature θc0 is calculated using the following formula using the previous predicted value of the controlled furnace temperature and the previous amount of heat supplied. 1)+b(1
) Calculate using the following formula using θC, θc, err (i, k) = θc (i, k) - θ
c'(i,k) (16) The updated a priori prediction error table θc, er of the control furnace temperature which is a storage area.
Set to r.

Here, the method for determining θC, which is the controlled furnace temperature, will be described in more detail.

First, the past atmospheric temperature (furnace temperature) of the combustion chamber detected by a PR thermocouple installed in the window above the hairpin part of the combustion chamber.
A moving average value of the combustion cycle time is determined, and a temporal and spatial smoothing method is used to further minimize the influence of switching the heat storage chamber.

The controlled furnace temperature of the middle window and the controlled furnace temperature of the end kiln are calculated using the following formula.

θc (i) = 0.375・ (θ (i) 10 (i
+1))+0.125・(θ (i-1)10 (
i+2)) (17)θc(1)=0.3
75・θ (1)+0.5・θ (2)+0.125・
θ (3) (18) θc(n) = 0.125・θ(n-1)+0.5・θ
(n) + 0.375・θ (On)
(19) Here, θ: past atmospheric temperature of the combustion chamber - moving average of combustion cycle time
It can be calculated by the method described in No. 0379 and Japanese Unexamined Patent Publication No. 61-47791. Using this method, the set furnace temperature θ in the next control cycle is predicted and the target furnace temperature Yr is determined.

Calculate the target furnace temperature Yr of the end kiln using the following formula: Y r (i, +1) = 0.75 ・θ (i, +1)
1) + 0.25・θ (+1 to i+1.)
(20) Here, i:l Y r (i, +1) = 0.25 - θ (i-1, +1) +0.75・θ (i, +1) (
21) Here, the target furnace temperature Yr of the inn intermediate window is calculated using the following formula.

Y r (i, kl) = 0.5・θ (i, +1) +
O, ZS・(θ (i-1, +1) 10 (i+1.
+1)) (22) where i: 2, 3, 4. ...Next, the predicted value Y of the controlled furnace temperature at the next control stage is calculated using the following formula, θc'(i, k) W P tf・(θc (i,
k) −Y, ) + Y.

Here, Ptf: Model constant b = Model constant M = Model constant Yo: Control furnace temperature reference value + b (1) · (Q (i, KN (K)) - Q o
) (24) Next, calculate the current corrected heat amount ΔU using the following formula so that the predicted value of the controlled furnace temperature in the next control stage becomes the determined target furnace temperature value. 25) Here, Gopt: Operator gain. θc(i,
k)>eHH and Δtl(i)>0.0, ΔLl(
i) -0,0 When θc(i,k)<eLL and ΔLl(i)<0.0, ΔU (i)-0,0 where HH,61LL: Protects the furnace body as the upper and lower limits of the furnace temperature. Is going.

Next, from the supply heat amount Q corresponding to the current control stage in the previous carbonization cycle in the storage area and the above corrected heat amount ΔU, the window section supply heat amount Q
Calculate K using the following formula, Q K (i) = Q (i, K
N(K))+ΔU (i) (26) Next, find the set flow rate for each adjustment cock. Calculate the window gas flow rate FS from the window supply heat quantity QK and the fuel gas heat quantity using the following formula. However, when V MAX < F 5 (i), F 5 (i)
= V MAXV MIN > F 5(i) (0 o'clock FS(i) = VMIN where VMAX, VMIN
: Upper and lower limit values of the gas flow rate flowing to the adjustment cock Next, when the fuel gas is odd numbered, the flow rate V set to be supplied to each effective adjustment cock (even numbered adjustment cock) is calculated.

Calculate the flow rate for the intermediate adjustment cock using the following formula: V set (i) = F s (i)
(28) where i: 2, 4, 6.・・・
・Calculate the flow rate for the end adjustment cock using the following formula.

Vset(i)=0.5・Fs(i)
(29) where i: 01. ON Next, when the fuel gas is even-numbered, calculate the flow rate V set to be supplied to the effective adjustment cock (odd-numbered adjustment cock) JIL.

Calculate the flow rate for the intermediate adjustment cock using the following formula.

V set (i) = F s (i)
(30) where i: 1, 3, 5.・・・
- Next, extract the effective adjustment cock during the current switching cycle from the fuel mode, and calculate the opening degree to be set for the adjustment cock from the fuel flow rate supplied to the adjustment cock.

First, calculate the flow rate ratio P using the following formula, P (i) = -Vset (i)
(31)F (k-1) Next, the set opening degree φ is calculated using the following formula.

φ(1)Ten αF'(1) 10βP”(1) 10γP2(i)
+δP (i)+ε (32) where α, β, γ
, δ, ε: The adjustment cock opening is set using the set opening φ obtained from the model constants or more. In addition, the difference between the target furnace temperature value and the controlled furnace temperature value is calculated as a control deviation using the following formula: θc, err(i, k) = a err−θc,
err (1, k-1)+ a qerr-(Yr (
i, k)-θc(i, k)) (33) where αerr: model constant αqerr: model constant Next, an alarm is output to the operator under the following conditions.

θc, err(i, k)l > θc, err,
HH (34) where θc, err, HH: control deviation limit value The model constants described above are determined in advance from the furnace operation results at the end of the carbonization process by applying, for example, a regression analysis method.

By performing the above calculation every time the fuel gas is switched, setting the adjustment cock for fuel gas flow rate adjustment, and controlling the set value of the fuel gas flow control system, the response delay of the controlled furnace temperature to changes over time in the set furnace temperature pattern can be delayed. This is a coke oven window furnace temperature control method characterized by keeping the controlled furnace temperature at a set furnace temperature by minimizing the time.

FIG. 3 diagrammatically shows the procedure of the window furnace temperature control method described above.

First, the previously set opening degree is read from the opening degree detector installed for each adjustment cock, and the effective amount of heat q supplied to the adjustment cock is calculated from the opening degree φ.

Next, this amount of heat q is converted into the amount of heat supplied to the window QM, and is stored in the amount of heat supplied table Q, which is a storage area.

Next, the controlled furnace temperature θC is calculated from the detected furnace temperature, and the a priori prediction error θc, err of the controlled furnace temperature is determined and stored in the a priori prediction error table of the controlled furnace temperature.

Next, the set furnace temperature is predicted based on the preset furnace temperature pattern θ, and the target furnace temperature value Yr is calculated.

Next, the predicted value Y of the controlled furnace temperature is calculated, the corrected heat amount ΔU is obtained, and the corrected amount is limited by upper and lower limiters.

Next, the amount of heat QK supplied to the window section is calculated, converted to window section gas Fs, and the flow rate is limited by upper and lower limiters.

Next, the fuel flow rate V set for each effective control cock is determined, and the control cock opening degree φ is calculated and set to control the fuel gas flow rate.The difference between the target furnace temperature value and the control furnace temperature value is determined as a control deviation, and the control temperature is set to exceed the limit value. If this occurs, an operator alarm is output and the coke oven window furnace temperature is controlled.

[Effects of the Invention] An example of the results of the operation carried out according to the present invention as described above is shown in FIGS. 4(a) and 4(b).

FIG. 4(a) shows the previous value and current value of the a priori prediction error of the controlled furnace temperature for one cycle.

At each time from coal charging to extrusion, the difference in a priori prediction error between the previous and current controlled furnace temperatures is extremely stable at ±3°C, and almost the same operation is repeated like a coke oven. It can be seen that this method is superior in this system.

FIG. 4(b) is a diagram showing the result of controlling the set furnace temperature pattern of the kiln as a target value in programmed heating.

The response delay of the controlled furnace temperature to the change in the set furnace temperature pattern over time was extremely small, and the controlled furnace temperature was kept at the set furnace temperature and stable, and the amount of heat consumed could be reduced by about 10%.

As described above, by implementing the window furnace temperature control according to the present invention, there is an excellent effect that extremely stable coke oven operation as shown in FIG. 4(b) can be obtained.

[Brief explanation of drawings]

Figure 1 is a control configuration diagram of the window furnace temperature control system, Figure 2 is a simplified diagram of a coke oven, Figure 3 is a diagram illustrating the procedure of the window furnace temperature control method, and Figure 4 is a diagram of the window furnace temperature control system. (a) and (b) are diagrams showing the operation results when window furnace temperature control was performed. A: Carbonization chamber B: Combustion chamber C: Heat storage chamber D: Adjustment cock and 4 others A: Carbonization chamber B: Combustion chamber C: Heat storage chamber D: Adjustment cock

Claims (1)

[Scope of Claims] 1. In a coke oven operation in which the set oven temperature pattern of the carbonization chamber in the carbonization process is predetermined based on the operating conditions and charging specifications of the coke oven, each time the fuel gas is switched, the supply to each previous oven is determined. Calorie estimation and a priori prediction error of control furnace temperature are calculated and recorded in the memory area of the current carbonization cycle, and then the control furnace temperature in the next control stage corresponds to the current control stage of the previous carbonization cycle in the storage area. The prediction is made based on the supplied heat amount, the a priori prediction error in the next control stage, and the current controlled furnace temperature, and the set furnace temperature in the next control stage is predicted from the set furnace temperature pattern, and then the target furnace temperature value is calculated. is determined, and the amount of correction of the amount of heat supplied is determined based on the difference from the predicted value of the controlled furnace temperature at the next control stage, and from the amount of heat supplied to each furnace at the current point of the previous carbonization cycle,
Calculate the amount of heat supplied to each kiln this time, determine the set gas flow rate for each adjustment cock from the determined amount of heat supplied to each kiln, and set the adjustment cock opening degree by estimating the cock opening degree from the fuel gas flow rate each time the fuel gas is switched. By controlling the set value of the fuel gas flow rate control system, the response delay time of the control furnace temperature to the change in the set furnace temperature pattern over time is minimized, the control furnace temperature is maintained at the set furnace temperature, and the target furnace temperature is maintained. The temperature control for each furnace of a coke oven is characterized in that the difference between the temperature value and the control furnace temperature value is used as a control deviation, and when the deviation value exceeds a certain amount, an alarm is output to the operator to notify the operator that there is an abnormality. Method. 2. When performing furnace temperature control for each kiln, calculate the moving average value of the past atmospheric temperature of the combustion chamber - the combustion cycle time,
In order to further minimize the effects of switching the heat storage chamber, temporal and spatial smoothing is performed to minimize fluctuations in the combustion gas flow rate, prevent hunting in the controlled furnace temperature, and set the controlled furnace temperature. 2. The method for controlling the temperature of each furnace in a coke oven according to claim 1, wherein the furnace temperature is maintained at a constant temperature.