JP2947678B2 - Burner combustion control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CGL (Continuous G)
alvanizing Line), CAL (Continuous Annealing L)
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burner combustion control system used for controlling steel temperature in a steel continuous line such as a ine), and more particularly to a burner combustion control system provided with a technology that quickly responds to a change in combustion load due to a change in the size of a steel material.

[0002]

2. Description of the Related Art Conventionally, in a steel continuous line for continuously heating steel materials, a burner combustion control system excellent in temperature stability and fuel saving has been widely used.

In this burner combustion control system, for example, a furnace having a plurality of zones along a traveling direction of a steel material, each burner is individually arranged in a plurality of blocks constituting these zones, and is supplied to each of the burners. The flow rates of fuel and air are controlled respectively.

FIG. 4 is a block diagram showing a burner combustion control system of this type. This burner combustion control system
A steel material temperature setting system that determines the required combustion amount based on the temperature of the steel material, a furnace temperature setting system that determines the required combustion amount based on the furnace temperature, and combustion from one of the steel material temperature setting system and the furnace temperature setting system The combustion control system controls the flow rate of fuel or the like supplied to the burner based on the required amount.

The steel material temperature setting system includes a steel material temperature controller 3 for obtaining a required combustion amount M from a control deviation between a steel material temperature set by the CPU 1 and a steel material temperature detected by the steel material temperature detector 2. A zone sharing unit 4 for multiplying a required combustion amount M from the steel material temperature controller 3 by a zone sharing ratio corresponding to each zone to obtain a fuel flow set value SV _ZO, and a fuel flow set value from the zone shared unit 4 and 1 And a zone fuel flow controller 5 for obtaining a required combustion amount _MZO for the zone from a control deviation from the fuel flow _PVZO for the entire zone.

On the other hand, the furnace temperature setting system, obtains the combustion demand M _R from the control deviation between the furnace temperature PV _R detected by the furnace temperature set value SV _R and furnace temperature detector 6 provided from the CPU1 And a furnace temperature controller 7.

[0007] The combustion control system, low-select unit for transmitting select a smaller value ones of the combustion demand M _R from the combustion demand M _ZO and furnace temperature adjusting meter 7 from zone fuel flow rate control meter 5 8 and the fuel demand M _LOW from the low select section 8
Over the block injection ratio between the block dividing unit 9 for determining the fuel flow rate setting value SV _BL of the block, and fuel flow control system and air fuel control system is provided.

Here, the fuel flow control system comprises a fuel flow set value SV _BL from the block sharing unit 9 and a fuel flow detector 10.
The fuel flow rate adjusting meter 11 for determining the manipulated variable from the control deviation between the fuel flow rate PV _F detected by the fuel flow rate adjusting meter 1
And a fuel flow rate adjusting valve 12 for adjusting the fuel flow rate in response to an operation amount from the controller 1.

On the other hand, air flow control system, air-fuel ratio setting unit 13 for determining the air flow rate set value by multiplying the air-fuel ratio to the fuel flow rate setting value SV _BL from the block sharing ratio 9, from an air-fuel ratio setting unit 13 an air flow adjusting meter 15 for determining the manipulated variable from the control deviation between the air flow rate PV _a detected by the air flow rate set value and the air flow detector 14, adjusts the air flow rate by receiving an operation amount of the air flow adjusting meter 15 And an air flow regulating valve 16.

[0010]

However, in the above-described burner combustion control system, the response time of the air-fuel ratio control and the time constant of the furnace are large. When changing the temperature set value, there is a problem that the response speed of the temperature change is slow.

Here, the fact that the time constant of the furnace is particularly large is as follows.
From the viewpoint of improving the response speed, it is a problem that is difficult to solve by an approach in which a method for obtaining an operation amount or the like such as an air-fuel ratio control method is improved to quickly obtain an operation amount. In addition, the slow response speed of the temperature change has a problem in that a large amount of poor quality steel material is generated due to a change in size or the like.

The present invention has been made in view of the above circumstances, and has as its object to provide a burner combustion control system capable of improving the response speed of a temperature change to a change in a heat capacity of a steel material or a set temperature of a steel material.

[0013]

The invention according to claim 1 has a burner for burning and heating a steel material, and the burner is controlled so that a control deviation between a temperature of the steel material and a set value of the steel material is set to zero. In the burner combustion control system to be controlled, the necessary heat quantity of the steel material is obtained from the data belonging to the heat capacity of the steel material input from the outside and the steel material temperature set value, and the steel material is formed based on the required heat quantity and the control deviation. Induction heating means for induction heating, when changing the steel material to another steel material having a different heat capacity, and when changing the steel material temperature set value, at least one of the changes, the combustion heating by the burner And a compensating means for compensating a response delay by induction heating by the induction heating means.

[0014]

Therefore, the invention corresponding to claim 1 takes the above-mentioned means, so that the induction heating means is externally input when the steel material is changed or the steel temperature set value is changed accordingly. The required heat quantity of the steel is obtained from the data pertaining to the heat capacity of the steel and the set temperature of the steel, and based on the required heat and the control deviation, the steel is directly heated to compensate for the response delay of the combustion heating by the burner. Because
The response speed of the temperature change with respect to the change of the heat capacity of the steel material and the set value of the steel material temperature can be improved.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a block flow of a burner combustion control system according to an embodiment of the present invention. The same parts as those in FIG. 4 are denoted by the same reference numerals, and the description thereof will be omitted. Is described only.

That is, in this burner combustion control method, combustion heating by a burner having a slow response due to a large time constant of the furnace is compensated for by induction heating having a fast response acting directly on the steel material. Is provided with an induction heating system for induction heating the steel material and a burner adjustment system that harmonizes this induction heating system with the conventional burner combustion control system,
In place of the conventional steel temperature controller 3, the steel set temperature SV from the CPU 1 and the steel temperature P from the steel temperature detector 2 are used.
A speed-shaped steel material temperature controller 20 for obtaining a change amount (hereinafter referred to as ΔMV) of an operation amount corresponding to a required combustion amount from a control deviation from V is provided.

Here, upon receiving the steel material set temperature SV from the CPU 1, the induction heating system obtains the necessary heat quantity of the steel material using the data pertaining to the heat capacity of the steel material which is set and inputted in advance, and uses the required heat quantity for induction heating. A distribution calculation logic 21 for calculating a required power change (hereinafter referred to as ΔP) and a fuel flow required for combustion control (hereinafter referred to as ΔFc), and a ΔP calculated by the distribution calculation logic 21.
A power correction unit 22 for converting ΔMV from the steel material temperature controller 20 into a correction value ΔP (hereinafter referred to as ΔP ′) so as to correct an error between the actual power change and an actual power change; ΔP from the power correction unit 22 and ΔP from the power correction unit 22
After receiving and P ', the output power from the power setting unit 23 that converts the power setting value SV _n, the power value PV _n detected by the power set value SV _n and the power meter 24 from the power setting unit 23 A power controller 25 for transmitting a value and an induction heater 26 for inductively heating a steel material by electric power from the power controller 25 are provided.

The distribution calculation logic 21 is connected to a data input unit (not shown) as compensation means for setting and inputting data relating to heat capacity and a steel material temperature set value in response to a change in steel material or process. .

The burner adjusting system includes a steel material temperature controller 2.
ΔMV from 0 is used as a correction value of the fuel demand (hereinafter, Δfc ′
), And the distribution calculation logic 21 calculates the required fuel amount M ′ to change ΔFc to the target.
And a fuel demand setting unit 28 for receiving the fuel demand correction amount 27 and Δfc ′ from the fuel demand correction unit 27, and calculating and inputting the required fuel quantity M to the zone sharing ratio unit 4. Next, the operation of the burner combustion control system will be described. First, a steel material is continuously supplied into a furnace, and is burned and heated at a predetermined steel material temperature set value SV1 by a burner.

In this state, when the current steel material (hereinafter, referred to as the current steel material) is changed to another next steel material (hereinafter, referred to as the next steel material), the CPU 1 sends the next steel material to the position Xm before the induction heater 26. At this time, the steel set temperature SV2 of the next steel is transmitted to the distribution calculation logic 21.

When the distribution calculation logic 21 receives the steel set temperature SV2 from the CPU 1, the distribution calculation logic 21 calculates the difference in calorific value of the next steel material with respect to the required calorific value of the current steel material based on the following equation (1). ΔCAL = W2 ・ D2 ・ V2 ・ G2ＴH2 ・ T2 -W1 ・ D1 ・ V1ＧG1 ・ H1 ・ T1 (1) where i = current and next steel (1; current steel, 2; next steel) Then, ΔCAL; increment of heat quantity (kca) taken out of the furnace by the next steel material
1 / H) Wi; steel width × 10 ⁻³ (m), example: changed by changing steel size Di: steel thickness × 10 ⁻³ (m), example: changed by changing steel size Vi: actual delivery speed of steel × 60 (m / h), e.g., changed by changing the line speed Gi: Specific gravity of steel material (kg / m ³ ), Example: Change due to change in steel type Hi: Specific heat of steel (kcal / kg · ° C), Example: Change due to change in steel type Ti; Steel set temperature (° C), Example: Change due to change in steel type, etc. Can be expressed. Wi / Di / Vi / Gi / Hi represents the heat capacity of the steel material, and is set and input in advance through the data input unit.

When the calorific value difference ΔCAL is obtained in this way, the distribution calculation logic 21 next calculates the calorific value difference ΔCA
L is calculated by the following equation (2).
Is converted to ΔP. ΔP = ΔCAL · K / Na (2) where K is the calorific value conversion coefficient (kw · h / kcal) Na; the efficiency of the induction heater 26 The distribution calculation logic 21 calculates the following equation (3) from ΔCAL: Find ΔFc. ΔFc = ΔCAL / {Ca · Nb} (3) ΔFc: Required fuel flow rate change (Nm ³ ) Ca; calorific value of fuel gas per unit volume (kcal /
Nm ³ ) Na; furnace efficiency After calculating these two change amounts ΔP and ΔFc, this ΔP
It is determined by the following equation (4) whether or not the supply of power can be supplied only by the induction heater 26. P _min ≦ P1 + ΔP ≦ P _max (4) P _max ; Maximum active power of the next steel material (kw) P _min ; Minimum active power (kw) P1: Power of the current steel material (kw) ΔP; Induction by changing to the next steel material Heater 2
6 Load change (kw)

Here, a case will be described in which the determination result of the expression (4) indicates that only the induction heater 26 can cover the result. At this time, the distribution calculation logic 21 determines the required combustion amount M ′ with the target ΔFc as shown in the time chart of FIG. 2 in the shortest time allowed by the restriction of the rate of change of the fuel flow rate of the furnace with ΔFc obtained by the equation (2). In addition to the output, ΔP used for induction heating with a fast response is output so as to compensate for the increase in the required combustion amount M ′. That is, in total, the next steel material is always heated at a required heat amount obtained by adding ΔCAL to the current heat amount.

When the result of the determination in the expression (4) indicates that the induction heater 26 is not sufficient, the distribution calculation logic 21 similarly determines the burner combustion amount in advance by a ramp function as shown in the time chart of FIG. The required combustion amount M 'is output so as to increase or decrease the temperature, and ΔP for induction heating is output so as to compensate for the required combustion amount M'.

On the other hand, the speed type steel material temperature controller 20 has a CPU
A manipulated variable .DELTA.MV based on the deviation between the steel material set temperature from 1 and the steel material temperature from the steel material temperature detector 2 is output.
It is converted to c 'and sent.

When the correction value ΔFc ′ and the required fuel amount M ′ are received, the fuel requirement setting unit 28 adds ΔFc ′ and the required fuel amount M ′ to the previously required fuel requirement M _n−1 , and this time, set input to zone sharing ratio 4 seeking fuel demand M _n.

The zone sharing ratio unit 4 multiplies the required fuel amount _Mn by the zone sharing ratio corresponding to each zone in order to allocate the required fuel amount _Mn received from the fuel request setting unit 28 to each zone. The fuel flow set value SV _ZO for one entire zone is obtained, and this fuel flow set value SV _ZO is input to the zone fuel flow controller 5. Hereinafter, based on the fuel flow set value _SVZO , the combustion control system controls the combustion heating of the next steel material by the burner using the air flow control system and the fuel control system. On the other hand, in order to compensate for the response delay of the combustion heating by the burner, the induction heating system performs the induction heating of the next steel material.

That is, Δ by the distribution operation logic 21
In parallel with the output of P, the speed section steel temperature controller 20 uses C
An operation amount ΔMV based on a deviation between the steel material set temperature from the PU 1 and the steel material temperature from the steel material temperature detector 2 is output. The operation amount ΔMV is calculated by the power correction unit 22 as the power correction value Δ
It is converted to P 'and transmitted.

The power correction value ΔP ′ and the power change ΔP
The power setting unit 23 that has received the power setting value SVn _-1 adds ΔP ′ and ΔP to the previously set power setting value SV _n−1 to obtain the current power setting value SV _n and inputs the setting to the power controller 25.

[0031] The power adjusting meter 25 sends an output power value based on a deviation between the power value PV _n from the set power level SV _n and the power meter 24 from the power setting unit 23, an induction heater 26 output power value Induction heating of the next steel material based on.

As described above, according to the burner combustion control method of this embodiment, when the steel material is changed and the steel material temperature set value is changed accordingly, the distribution calculation logic 21 uses the data belonging to the heat capacity of the steel material and the steel material temperature set value. The required calorific value of the steel material is obtained based on
c and the change Δ in the power applied to the induction heater 26
Find P.

On the other hand, since these ΔFc and ΔP are calculated, when they are used in an actual system, based on ΔMV corresponding to the control deviation between the steel material temperature and the steel material set temperature,
Each error is corrected and converted into a required combustion amount M and a set power value.

Thus, the combustion heating by the burner is performed based on the required combustion amount M, and the induction heater 26 directly induces the heating of the steel material based on the set power value to delay the response of the combustion heating by the burner. Since the compensation is performed, the response speed of the temperature change to the change of the steel material and the change of the steel material temperature set value can be improved.

Further, since it is possible to respond to a change in the amount of heat due to a change in the type of steel material, a change in the size of the steel material, and a change in the set temperature of the steel material with a high response speed, the length of the defective steel material can be reduced as compared with the case where the heat amount changes only with the burner. Can be shortened.

Further, the burner combustion control system of this embodiment is as follows.
The required amount of combustion M 'from the distribution calculation logic 21 is increased within the range of the rate of change of the fuel flow rate of the furnace, and the steel is directly heated by the induction heating means, so that the furnace is not damaged. .

Further, the burner combustion is mainly used, the induction heater 26 is used as an auxiliary, and the upper and lower limits of the output power are set so that the power is not used as much as possible. .

In this embodiment, the distribution operation logic 2
1, the case where the required combustion amount M 'and ΔP are output has been described. However, the present invention is not limited to this, and only ΔP is output from the distribution calculation logic 21 and this ΔP is output at such a speed that the fuel control of the burner can follow. Even if it is changed, the present invention can be similarly implemented. In addition, the present invention can be implemented with various modifications without departing from the scope of the invention.

[0039]

As described above, according to the present invention, the induction heating means is provided, and when the amount of heat given to the steel material is changed, for example, by changing the type of the steel material while the burner is burning the steel material. Since the heating means compensates for the response delay of combustion heating by the burner by directly inducing heating of the steel material, the burner combustion control method that can improve the response speed of the temperature change to the change of the heat capacity of the steel material and the set value of the steel material temperature is improved. Can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a block flow of a burner combustion control system according to one embodiment of the present invention.

FIG. 2 is a time chart in the embodiment.

FIG. 3 is a time chart in the embodiment.

FIG. 4 is a diagram showing a block flow of a conventional burner combustion control system.

[Explanation of symbols]

1 ... CPU, 2 ... Steel material temperature detector, 4 ... Zone sharing unit,
5 zone fuel flow controller, 6 furnace temperature detector, 7
Furnace temperature controller, 8: low select unit, 9: block sharing ratio unit, 10: fuel flow detector, 11: fuel flow controller,
12: fuel flow control valve, 13: air-fuel ratio setting unit, 14: air flow detector, 15: air flow controller, 16: air flow control valve, 20: speed steel temperature controller, 21: distribution calculation logic, 22: power correction unit, 23: power setting unit, 24
... power meter, 25 ... power controller, 26 ... induction heater, 27 ... fuel demand correction unit, 28 ... fuel demand setting unit.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G05B 11/32 G05B 11/32 Z 11/36 11/36 K G05D 23/00 G05D 23/00 F H05B 6/06 H05B 6 / 06 (56) References JP-A-1-266935 (JP, A) JP-A-61-212439 (JP, A) JP-A-61-24456 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G05D 23/00-23/32

Claims (1)

(57) [Claims] 1. A burner combustion control system for controlling a burner for burning and heating a steel material such that a control deviation between a temperature of the steel material and a set temperature of the steel material is set to zero. An induction heating means for inducing heating of the steel material based on the required heat amount and the control deviation, while obtaining a necessary heat amount of the steel material from the data belonging to the heat capacity of the steel material and the steel material temperature set value; The response delay of the combustion heating by the burner is compensated by the induction heating by the induction heating means for at least one of the case of changing to another steel material having the above and the case of changing the steel material temperature set value. A burner combustion control system comprising a compensation means.