JP2017101841A - Furnace temperature control method for heating furnace and furnace temperature control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively operate a continuous burner and a regenerative burner to achieve a target temperature while suppressing consumption of fuel in one control band.SOLUTION: A furnace temperature control method for a heating furnace controls the furnace temperature T by choosing one of single control for operating the continuous burner 2 only and combination control for operating both of the continuous burner 2 and the regenerative burner 3 based on a total amount Q of a fuel flow amount to be supplied to one control band Z1 or the furnace temperature T, in one control band Z1.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a furnace temperature control method and a furnace temperature control device for a heating furnace suitable for an industrial heating furnace.

  A general continuous furnace has a plurality of control zones (for example, pre-tropical zone, heating zone, soaking zone), and one control zone is usually a burner of either a continuous burner or a regenerative burner. Is equipped. In one control zone, the furnace temperature is controlled by adjusting the combustion amount of the burner so that the furnace temperature becomes the target temperature under fuel flow control by a single type of burner. For example, Patent Literatures 1 and 2 disclose techniques for calculating the heat balance in the heating furnace and determining the combustion amount in each control zone.

JP 2011-162804 A JP 2007-308777 A

However, as in the techniques described in Patent Documents 1 and 2, when determining the fuel flow rate of each burner from the heat balance, the calculation load is higher than that of a general heating furnace, and the size and charging / extraction temperature are also high. If there is a material to be heated in the furnace, the calculation accuracy becomes low and fuel may be consumed excessively.
Also, the conventional furnace temperature control technology in one control zone is a case where a continuous burner is equipped in one control zone, or a heat storage type burner is equipped in one control zone However, the point that the furnace temperature is controlled by adjusting the burner combustion amount under the control of the fuel flow rate with a single type of burner is the same, and the advantages of each of these two types of burners are still fully utilized. There is room for consideration.

That is, the regenerative burner is capable of alternating combustion in which combustion and exhaust are alternately repeated, and by storing the exhaust heat in the heat accumulator, combustion can be performed more efficiently than the continuous burner. However, a regenerative burner that does not have a pilot burner needs to ignite the main burner separately, and there is a problem that the introduction cost is higher than that of a normal burner. On the other hand, since a continuous burner having a pilot burner can be burned continuously, the combustion state can be managed regardless of the state of the furnace temperature, but there is a problem that it is inferior to a heat storage burner in terms of combustion efficiency.
Therefore, the present invention has been made paying attention to such problems, and the target can be achieved while suppressing fuel consumption in one control zone by effective operation of the continuous burner and the heat storage burner. It is an object of the present invention to provide a furnace temperature control method and a furnace temperature control device for a heating furnace capable of achieving the furnace temperature.

[Invention 1]
In order to solve the above problems, a furnace temperature control method for a heating furnace according to an aspect of the present invention includes a plurality of control zones capable of independently controlling the furnace temperature, and one of the plurality of control zones is provided. A heating furnace in which a continuous burner having a pilot burner capable of continuous combustion and a regenerative burner capable of alternating combustion that alternately repeats combustion and exhaust without having a pilot burner are installed in the control zone The method of controlling the furnace temperature of the above-mentioned, wherein in the one control zone, only the continuous burner is operated based on the total flow rate Q or the furnace temperature T of the fuel flow rate to be supplied to the one control zone. The furnace temperature is controlled by selecting either one of the control and the combined control for operating the continuous burner and the heat storage burner together.

[Invention 2]
Here, in the furnace temperature control method for a heating furnace according to one aspect of the present invention, when the furnace temperature T is lower than the first management temperature T1 at which the fuel self-ignites, the furnace temperature is controlled by the single control. preferable.

[Invention 3]
Further, in the furnace temperature control method for a heating furnace according to one aspect of the present invention, the total flow rate of fuel to be supplied to the one control zone when the furnace temperature T exceeds the first management temperature T1. When Q is less than the first management flow rate Q1 (Q <ΣA + ΣC), the furnace temperature is controlled by the single control, and when Q is greater than the first management flow rate Q1 (Q ≧ ΣA + ΣC), the furnace is controlled by the combined control. It is preferable to control the temperature. However, the first management flow rate Q1 is the sum of the minimum value ΣA of the total fuel flow rate of the continuous burner and the minimum value ΣC of the total fuel flow rate of the regenerative burner.

[Invention 4]
In the furnace temperature control method for a heating furnace according to an aspect of the present invention, the total flow rate Q of the fuel flow rate to be supplied to the one control zone when the furnace temperature exceeds the first management temperature T1. However, when the first management flow rate Q1 is less than the second management flow rate Q2 (ΣA + ΣC <Q <ΣA + ΣD), as the combined control, the fuel flow rate of the continuous burner is burned at the minimum value A and the heat storage It is preferable to control the furnace temperature by the first combined control that controls the fuel flow rate of the burner in the range from the minimum value C to the maximum value D. However, the second management flow rate Q2 is the sum of the minimum value ΣA of the total fuel flow rate of the continuous burner and the maximum value ΣD of the fuel flow rate of the regenerative burner.

[Invention 5]
In the furnace temperature control method for a heating furnace according to an aspect of the present invention, the total flow rate Q of the fuel flow rate to be supplied to the one control zone when the furnace temperature exceeds the first management temperature T1. However, when the second control flow rate Q2 or more, as the combined control, the fuel flow rate of the regenerative burner is burned at the maximum value D, and the fuel flow rate of the continuous burner is maximized from its minimum value A. It is preferable to control the furnace temperature by the second combined control that is controlled within the range of the value B.

[Invention 6]
Further, in the furnace temperature control method for a heating furnace according to an aspect of the present invention, in the temperature rising process before the heating furnace reaches the target temperature TU of the furnace temperature, the furnace temperature is the first management temperature T1. The furnace temperature is controlled by the single control until reaching the second management temperature T2 that exceeds the target temperature TU and is lower than the target temperature TU. When the heating furnace is in the temperature raising process, the furnace temperature is the second management temperature T2. When the temperature is exceeded, the furnace temperature is controlled by the combined control, and in the temperature lowering process in which the heating furnace lowers the target temperature TU itself of the furnace temperature, until the furnace temperature reaches the first management temperature T1, It is preferable to control the furnace temperature by the combined control and to control the furnace temperature by the single control when the furnace temperature becomes lower than the first management temperature T1.

[Invention 7]
Moreover, in order to solve the said subject, the furnace temperature control apparatus of the heating furnace which concerns on 1 aspect of this invention is equipped with the several control zone which can control a furnace temperature independently, Of these control zones, In one control zone, a continuous burner with a pilot burner capable of continuous combustion and a regenerative burner capable of alternating combustion that alternately repeats combustion and exhaust without a pilot burner were installed. A furnace temperature control device for controlling the furnace temperature of the heating furnace, the furnace temperature meter for detecting the furnace temperature in the one control zone, the flow meter for the continuous burner for detecting the fuel flow rate of the continuous burner, , A heat storage burner flow meter for detecting a fuel flow rate of the heat storage burner, and detection values of the furnace thermometer, continuous burner flow meter, and heat storage burner flow meter are input and the one control Combustion of the continuous burner and the regenerative burner in a belt And a control unit capable of controlling the fuel flow rate, and the control unit operates only the continuous burner based on the total flow rate Q or the furnace temperature T of the fuel flow rate to be supplied to the one control zone. Furnace temperature is controlled by selecting either single control or combined control for operating both the continuous burner and the heat storage burner together.

[Invention 8]
Here, in the furnace temperature control apparatus for a heating furnace according to an aspect of the present invention, the controller controls the furnace temperature by the independent control when the furnace temperature T is lower than the first management temperature T1 at which the fuel self-ignites. It is preferable to control.

[Invention 9]
Moreover, in the furnace temperature control apparatus for a heating furnace according to one aspect of the present invention, the control unit should supply the one control zone when the furnace temperature T exceeds the first management temperature T1. When the total flow rate Q of the fuel flow rate is less than the first management flow rate Q1 (Q <ΣA + ΣC), the furnace temperature is controlled by the single control, and when it is equal to or higher than the first management flow rate Q1 (Q ≧ ΣA + ΣC), It is preferable to control the furnace temperature by the combined control. As described above, the first management flow rate Q1 is the sum of the minimum value ΣA of the total fuel flow rate of the continuous burner and the minimum value ΣC of the total fuel flow rate of the regenerative burner.

[Invention 10]
Further, in the furnace temperature control device for a heating furnace according to one aspect of the present invention, the control unit is a fuel to be supplied to the one control zone when the furnace temperature exceeds the first management temperature T1. When the total flow rate Q of the flow rate is not less than the first management flow rate Q1 and less than the second management flow rate Q2, the regenerative burner is burned with the fuel flow rate of the continuous burner at the minimum value A as the combined control. It is preferable to control the furnace temperature by the first combined control for controlling the fuel flow rate in the range from the minimum value C to the maximum value D. As described above, the second management flow rate Q2 is the sum of the minimum value ΣA of the total fuel flow rate of the continuous burner and the maximum value ΣD of the total fuel flow rate of the regenerative burner.

[Invention 11]
Further, in the furnace temperature control device for a heating furnace according to one aspect of the present invention, the control unit is a fuel to be supplied to the one control zone when the furnace temperature exceeds the first management temperature T1. When the total flow rate Q of the flow rate is equal to or greater than the second control flow rate Q2, as the combined control, the fuel flow rate of the regenerative burner is burned at the maximum value D, and the fuel flow rate of the continuous burner is It is preferable to control the furnace temperature by the second combined control that is controlled in the range of the minimum value A to the maximum value B.

[Invention 12]
Further, in the furnace temperature control apparatus for a heating furnace according to an aspect of the present invention, the control unit is configured so that the furnace temperature is the first temperature in the heating process before the heating furnace reaches the target temperature TU of the furnace temperature. The furnace temperature is controlled by the single control until it reaches the second management temperature T2 that exceeds the one management temperature T1 and less than the target temperature TU, and when the heating furnace is in the temperature rising process, the furnace temperature is When the temperature exceeds the second management temperature T2, the furnace temperature is controlled by the combined control. When the heating furnace lowers the target temperature TU itself of the furnace temperature, the furnace temperature becomes the first management temperature T1. Until the temperature reaches, the furnace temperature is controlled by the combined control, and when the furnace temperature becomes lower than the first management temperature T1, the furnace temperature is preferably controlled by the single control.

  According to the present invention, in one control zone, a continuous burner having a pilot burner and capable of continuous combustion, and a regenerative type capable of alternating combustion that alternately repeats combustion and exhaust without having a pilot burner. A burner is installed, and based on the total flow rate of the fuel flow to be supplied to one control zone or the furnace temperature, independent control that operates only the continuous burner and the continuous burner and the regenerative burner are operated together. Since either one of the combined control is selected and the furnace temperature is controlled, the target furnace temperature can be achieved while suppressing the fuel consumption in one control zone by the effective operation of the continuous burner and the regenerative burner. .

It is a schematic diagram of one Embodiment of a heating furnace provided with the furnace temperature control apparatus which concerns on 1 aspect of this invention, The figure (a) is the front view, (b) is a top view. It is a block diagram explaining the structure of a furnace temperature control apparatus. It is a flowchart of the furnace temperature control process which a furnace temperature control apparatus performs. It is a flowchart of the furnace temperature control process which a furnace temperature control apparatus performs. It is a graph which shows an example of the furnace temperature control based on a furnace temperature control process, a horizontal axis shows time and a vertical axis | shaft shows furnace temperature.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate. The drawings are schematic. For this reason, it should be noted that the relationship between the thickness and the planar dimension, the ratio, and the like are different from the actual ones, and the dimensional relationship and the ratio are different between the drawings. Further, the following embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, structure, and arrangement of components. Etc. are not specified in the following embodiments.

As shown in FIG. 1, this industrial heating furnace 10 has a plurality of control zones Z1, Z2, and Z3 (see FIG. 1B). In the example of the present embodiment, the heated material S such as slab, billet, and bloom is conveyed by a conveying device such as a walking beam (not shown), and the heated material S is heated to the extraction target temperature to be downstream. This is a continuous heating furnace that is sent to a rolling mill or the like.
The heating furnace 10 of this embodiment has the pre-tropical zone Z1, the heating zone Z2, and the soaking zone Z3 in order from the upstream side along the conveyance direction H of the to-be-heated material S as a some control zone. In addition, the pre-tropical zone Z1 on the upstream side is provided with an inlet 10a, and the soaking zone Z3 on the downstream side is provided with an extraction port 10b.
Each control zone Z1, Z2, Z3 is provided with a plurality of burners at appropriate positions, and each control zone Z1, Z2, Z3 can be independently controlled in furnace temperature. In the present embodiment, each of the control zones Z1, Z2, and Z3 is formed by one zone (zone), but may be constituted by a plurality of zones.

In the present embodiment, as shown in FIG. 1, a plurality of continuous burners 2 having pilot burners and a plurality of regenerative burners (regenerative burners) 3 having no pilot burners are provided in the pre-tropical zone Z1. Yes. Further, a plurality of continuous burners 2 are respectively provided at appropriate positions in the downstream heating zone Z2 and the soaking zone Z3. The continuous burner 2 in each of the control zones Z2 and Z3 supplies the combustion gas as a frame into the furnace, and the exhaust gas flows to the pre-tropical Z1 side and is released into the atmosphere via a chimney (not shown) through a chimney. Is done.
The heat storage burner 3 is an alternating combustion burner including a burner body and a heat storage body. In the example of the present embodiment, the two regenerative burners 3 facing each other are used as a pair, and combustion and exhaust gas suction are alternately repeated. Each regenerative burner 3 accumulates the heat of the exhaust gas in the heat storage body when the exhaust gas is sucked, and uses the accumulated heat for preheating the air (combustion air) supplied together with the fuel. The temperature can be raised to improve thermal efficiency. On the other hand, the continuous burner 2 is a normal burner that does not include a heat storage body and does not perform alternating combustion. Since the continuous burner 2 has a pilot burner, it can burn continuously and can manage the combustion state regardless of the furnace temperature state.

Hereinafter, the pre-tropical zone Z1 will be described in more detail.
As shown in FIG. 1, the pre-tropical zone Z1 is provided with a furnace thermometer 1 at an appropriate place such as the upper center of the furnace, and the furnace thermometer 1 can measure the furnace temperature at any time. In addition, each continuous burner 2 and each regenerative burner 3 of the pre-tropical Z1 are provided with a fuel pipe (not shown), a flow meter, and an adjustment valve capable of adjusting the fuel supply amount. The fuel flow at any time of the continuous burner 2 and each regenerative burner 3 can be measured by a flow meter.
As shown in FIG. 2, the furnace temperature information measured by the furnace thermometer 1 and the fuel flow information of each continuous burner 2 and each regenerative burner 3 at any given time independently indicate the pre-tropical zone Z1. It is input to the control unit 5 that can be controlled. The control unit 5 executes the furnace temperature control process, and each continuous time so that the furnace temperature T of the pre-tropical zone Z1 becomes the target temperature TU (for example, 1000 ° C.) based on the furnace temperature information and the fuel flow rate information at any time. The furnace temperature T can be controlled by controlling the fuel flow rate with the regulating valves of the type burner 2 and each heat storage type burner 3.

  Specifically, the control unit 5 includes a CPU (not shown) that controls the calculation and the entire system, a storage device and a ROM that store data such as a control program including a furnace temperature control process in a predetermined area, RAM for storing data read from the apparatus and ROM, and calculation results required in the calculation process of the CPU, external devices including a display device, an input device, a database, etc., and a host computer for managing the entire heating furnace 10 And an interface that mediates data input / output, and these are connected to each other via a bus that is a signal line for transferring data so that data can be exchanged.

  The control unit 5 executes a furnace temperature control process according to a control command for setting the target temperature TU of the pre-tropical zone Z1 from a host computer that manages the heating furnace 10 as a whole. When the controller 5 performs the furnace temperature control process, as shown in FIG. 3, first, the process proceeds to step S11, where the furnace temperature information from the furnace thermometer 1, each continuous burner 2, and each regenerative burner. The fuel flow rate information from 3 is acquired, and the process proceeds to step S12. In step S12, it is determined whether or not the furnace temperature T has reached a first management temperature T1 (for example, 760 ° C.). Here, as the first management temperature T1, a temperature equal to or higher than the self-ignition point of the fuel is set in advance.

  If the furnace temperature T is lower than the first management temperature T1 (No), the process proceeds to step S14. If the furnace temperature T is equal to or higher than the first management temperature T1 (Yes), the process proceeds to step S13. In step S13, it is determined whether or not the furnace temperature has reached a second management temperature T2 (for example, 800 ° C.). The second management temperature T2 sets a temperature range between the ignition point and the extinguishing point of the heat storage burner 3 in order to burn the heat storage burner 3 safely and stably, and a target temperature TU (for example, The temperature is lower than 1000 ° C., and is set in advance to, for example, 40 ° C. to 100 ° C. higher than the first management temperature T1 (that is, 800 ° C. to 860 ° C. in the example of this embodiment).

If the furnace temperature T is lower than the second management temperature T2 (No), the process proceeds to step S14. In step S14, the furnace temperature is controlled only by the continuous burner 2 (hereinafter also referred to as “independent control”), and step S11 is performed. Return processing to. If the furnace temperature is equal to or higher than the second management temperature T2 (Yes), the process proceeds to step S15.
In step S15, it is determined whether or not the furnace temperature T has reached the target temperature TU. If the target temperature TU has been reached (Yes), the process proceeds to step S17. If not (No), the process proceeds to step S16. In step S16, the continuous burner 2 and the regenerative burner 3 are used in combination. (Hereinafter also referred to as “combination control”), and the process proceeds to step S17.

  Here, in the present embodiment, the control unit 5 performs the continuous control using the continuous burner 2 and the heat storage burner 3 together, based on the conditions shown in Tables 1 and 2 below. 2 and the fuel flow rate of the regenerative burner 3 are set.

Table 1 shows that the upper and lower limits of the fuel flow rate in each burner unit are A, the minimum value of the fuel flow rate in the continuous burner 2 unit is A, the maximum value is B, and the minimum value of the fuel flow rate in the regenerative burner unit 3 is C. , The maximum value is D. Note that the minimum value of the fuel flow rate in each burner means the minimum fuel flow rate necessary for maintaining a stable combustion state of each burner.
Further, the maximum value of the fuel flow rate in each burner means the maximum fuel flow rate within a range where a stable combustion state of each burner can be maintained. Table 2 shows the total flow rate Q to be supplied to the pre-tropical zone Z1 for each continuous burner 2 and each regenerative burner 3 when the fuel flow rate of each burner is set to the upper limit and the lower limit shown in Table 1. It shows how to distribute.

  That is, during combined control, the total flow rate Q to be supplied to the pre-tropical zone Z1 is the sum of the minimum value ΣA of the total fuel flow rate of the plurality of continuous burners 2 and the minimum value ΣC of the fuel flow rate of the plurality of regenerative burners 3 (Hereinafter, also referred to as “first management flow rate Q1”) (Q <ΣA + ΣC), the control unit 5 does not operate the regenerative burner 3 and uses only the continuous burner 2, Combustion in the range of the fuel flow rate of the continuous burner 2 from the minimum value A to the minimum value A + C (however, the minimum value C of the fuel flow rate of the regenerative burner 3 is smaller than the maximum value B of the fuel flow rate of the continuous burner 2) The single control to be executed is executed.

Further, during the combined control, the total flow rate Q of the fuel flow to be supplied is equal to or higher than the first management flow rate Q1 (Q1 = ΣA + ΣC ≦ Q), and the minimum value ΣA of the total fuel flow rates of the plurality of continuous burners 2 When the sum of the total fuel flow rate of the regenerative burner 3 is smaller than the sum (hereinafter also referred to as “second control flow rate Q2”) (Q <ΣA + ΣD = Q2), the control unit 5 While maintaining the fuel flow rate of the burner 2 at the minimum value A, the first combined control for burning the fuel flow rate of each heat storage burner 3 in the range from the minimum value C to the maximum value D is executed.
Further, in the combined control, when the total flow rate Q of the fuel flow to be supplied is equal to or higher than the second management flow rate Q2 (Q2 = ΣA + ΣD ≦ Q), the control unit 5 controls the fuel flow rate of each regenerative burner 3. Is maintained at the maximum value D, and the second combined control for burning the fuel flow rate of each continuous burner 2 in the range from the minimum value A to the maximum value B is executed.

In step S17, the presence or absence of a new control command from the host computer that manages the entire heating furnace 10 is monitored. That is, if the control command is maintained at the target temperature TU (No), the process returns to step S11. On the other hand, if a new control command for lowering the furnace temperature and setting the furnace temperature T to the target temperature drop value TD has been input (Yes), the process is returned and the process proceeds to the furnace temperature lowering process shown in FIG.
When the furnace temperature cooling process is executed by the control unit 5, as shown in FIG. 4, first, the process proceeds to step S21, where the furnace temperature information from the furnace thermometer 1, each continuous burner 2 and each regenerative burner are transferred. The fuel flow rate information from 3 is acquired, and the process proceeds to step S22. In step S22, it is determined whether or not the furnace temperature T during the temperature decrease has reached the first management temperature T1, and if it has reached the first management temperature T1 (Yes), the process proceeds to step S25, otherwise ( No) Move to step S23.

  In step S23, the fuel flow rate of the continuous burner 2 is set to the minimum value A, and in the subsequent step S24, the fuel flow rate of the regenerative burner 3 is decreased to the target flow rate so that the furnace temperature T becomes the target temperature drop value TD. The process returns to step S21. In step S25, the regenerative burner 3 is extinguished and the fuel flow rate of the continuous burner 2 is reduced to the target flow rate so that the furnace temperature T is set to the target temperature drop TD by independent control of the continuous burner 2, and the flow proceeds to step S26. To do. In step S26, it is determined whether or not the furnace temperature T has reached the target temperature decrease value TD. If the target temperature decrease value TD has been reached (Yes), the process is returned; otherwise (No), the process returns to step S25. The independent control for reducing the fuel flow rate of the continuous burner 2 to the target flow rate is continued until the temperature drop target value TD is reached.

Next, the operation and effect of the heating furnace 10 will be described.
This heating furnace 10 has a pre-tropical zone Z1, a heating zone Z2, and a soaking zone Z3 that can independently control the furnace temperature as a plurality of control zones, and conveys the material to be heated S along the conveyance direction H by a conveyance device. The heated material S is heated to the extraction target temperature and sent to a downstream rolling mill or the like.
According to this heating furnace 10, the furnace temperature of the pretropical zone Z1 can be set higher than the other control zones Z2 and Z3 by the flow of the combustion exhaust gas from the heating zone Z2 and the soaking zone Z3. Therefore, the material to be heated S is rapidly heated in the pre-tropical zone Z1, and the thermal conditions are almost uniformed toward the heating zone Z2, so that the productivity is improved. And, for each control zone Z1, Z2, Z3 of the heating furnace 10, the combustion amount of the burner in each control zone is controlled, and the furnace temperature in each control zone is adjusted to a predetermined temperature. It can be controlled to a desired furnace temperature pattern. Therefore, there is little variation in the temperature distribution in the furnace, and the heat uniformity of the material to be heated S is good.

  According to the heating furnace 10, the continuous burner 2 and the regenerative burner 3 are provided side by side in the pre-tropical zone Z1, which is one of the plurality of control zones Z1, Z2, and Z3. The control unit 5 of the tropical zone Z1 is a single control that operates only the continuous burner 2 based on the total flow rate Q or the furnace temperature T of the fuel flow to be supplied to the pre-tropical zone Z1, and the continuous burner 2 and the regenerative burner 3 Since the furnace temperature T is controlled by selecting either one of the combined control for operating both of them, the effective operation of the continuous burner 2 and the regenerative burner 3 suppresses fuel consumption in the pretropical zone Z1. The target furnace temperature can be achieved.

That is, in FIG. 5, when a control command for setting the target temperature TU of the pre-tropical zone Z1 is output from the host computer that manages the entire heating furnace 10 at the time point P0, the control unit 5 performs the furnace temperature control process described above. Execute. Since the furnace temperature T is lower than the first management temperature T1 at the time P0, the temperature rise is started by the single control that operates only the continuous burner 2.
Thus, according to the heating furnace 10, when the furnace temperature T is lower than the first management temperature T1 (for example, 760 ° C.) at which the fuel self-ignites, the furnace temperature T is controlled using only the continuous burner 2. Therefore, at the furnace temperature at which it is difficult to self-ignite the fuel, combustion is performed using only the continuous burner 2 having the pilot burner, so that the fuel can be reliably burned without generating unburned fuel.

In particular, as shown in FIG. 5, in this embodiment, at the time of temperature increase, even if the furnace temperature T exceeds the time point P1 at which the furnace temperature T is equal to or higher than the first management temperature T1, the furnace temperature T is the second management temperature. The temperature is raised by independent control until the point of P2 when T2 is reached.
That is, when the furnace temperature T is raised toward the target temperature TU, if the measured value of the furnace thermometer 1 is lower than the second management temperature T2, the continuous type even if it exceeds the first management temperature T1. When the furnace temperature is controlled only by the combustion of the burner 2 and the furnace temperature T exceeds the second management temperature T2, the use of the regenerative burner 3 is started. Therefore, according to this heating furnace 10, even when the furnace temperature T of the pre-tropical zone Z1 fluctuates due to opening / closing of the charging port 10a, the regenerative burner 3 does not cause a chattering operation that repeats ignition and extinguishing, and can be stably performed. It is possible to shift from single control to combined control while controlling the flow rate of the burner and the furnace temperature.

And according to this heating furnace 10, when the furnace temperature T exceeds 2nd management temperature T2, while the control command which maintains the pre-tropical zone Z1 at the target temperature TU is output (P2 in FIG. 5). P4) shifts to the combined control based on the flow rate management shown in Table 2. In other words, the combined control based on the flow rate management is continuous as shown in Table 2 when the total flow rate Q of the fuel flow to be supplied to the pre-tropical zone Z1 is less than the first management flow rate Q1 (Q <ΣA + ΣC). The furnace temperature is controlled by independent control using only the type burner 2.
Further, when the total flow rate Q of the fuel flow to be supplied to the pre-tropical zone Z is not less than the first management flow rate Q1 and less than the second management flow rate Q2 (ΣA + ΣC ≦ Q <ΣA + ΣD), the fuel flow rate of each continuous burner 2 is set. While burning at the minimum value A, the furnace temperature T is controlled by the first combined control for controlling the fuel flow rate of each regenerative burner 3 in the range from the minimum value C to the maximum value D.

Further, when the total flow rate Q of the fuel flow rate to be supplied to the pre-tropical zone Z is equal to or higher than the second management flow rate Q2 (ΣA + ΣD ≦ Q), the fuel flow rate of each regenerative burner 3 is burned at the maximum value D. The furnace temperature T is controlled by the second combined control for controlling the fuel flow rate of each continuous burner 2 in the range from the minimum value A to the maximum value B. In other words, when the fuel flow rate of the regenerative burner 3 reaches the maximum value D, the fuel flow rate of the continuous burner 2 is increased so that the furnace temperature T becomes the target temperature TU.
By this furnace temperature control, according to this heating furnace 10, the regenerative burner 3 having no pilot burner is always used above the fuel self-ignition point, and the minimum flow rate required for each burner to burn. Can be operated while always ensuring. Therefore, the furnace temperature can be controlled by safe and stable combustion, and the efficient heat storage burner 3 can be used with priority, so the furnace temperature T becomes the target temperature TU with the minimum fuel flow rate. Can be controlled.

Thereafter, when a control command for setting a new target temperature TD for lowering the temperature of the pre-tropical zone Z1 is output from the host computer that manages the entire heating furnace 10 at the time point P4, the temperature lowering process is performed to lower the target temperature itself. In this case, until the time point P5 when the temperature reaches the first management temperature T1, control is performed so that the furnace temperature T is lowered by the above-described combined control. When the furnace temperature T becomes lower than the first management temperature T1, independent control is performed. To control the furnace temperature.
In this example, after the time point P5, the temperature is lowered by independent control until the time point P6 when the temperature reaches the target temperature TD at the time of temperature drop. That is, when the furnace temperature decreases and the furnace temperature T becomes lower than the first management temperature T1, the regenerative burner 3 is extinguished so that the measured value of the furnace thermometer 1 becomes the target temperature drop value only by the continuous burner 2. The control unit 5 controls. As a result, even when the furnace temperature T fluctuates due to opening / closing of the charging port 10a or the like when the temperature is lowered, the ignition / extinguishing of the regenerative burner 3 is not repeated and the furnace temperature can be controlled stably.

As described above, according to the heating furnace 10, in all combustion processes of the pre-tropical zone Z1, when the furnace temperature T is lower than the first control temperature T1 where it is difficult to self-ignite the fuel, the continuous type having a pilot burner is used. When only the burner 2 is used for combustion and the temperature is equal to or higher than the first control temperature T1 at which the fuel self-ignites, the regenerative burner 3 having no pilot burner is appropriately used in combination and burned without causing unburned Fuel can be burned reliably.
Further, according to the heating furnace 10, when the furnace temperature T is equal to or higher than the first management temperature T1, the fuel flow rate of the continuous burner 2 having low efficiency is set to the minimum value A when the continuous burner and the heat storage burner are used in combination. The furnace temperature is adjusted by adjusting the fuel flow rate of the efficient regenerative burner 3 while burning. After that, when the regenerative burner 3 reaches the maximum flow rate D, the furnace temperature is adjusted by adjusting the fuel flow rate of the continuous burner 2. Since T is controlled, the target furnace temperature can be controlled at a minimum flow rate by effective operation of the continuous burner 2 and the regenerative burner 3.

Furthermore, according to this heating furnace 10, when the second management temperature T2 is set between the first management temperature T1 and the target temperature TU, and the temperature rises, the furnace temperature T becomes equal to or higher than the second management temperature T2. Since the use of the heat storage burner 3 is stopped when the furnace temperature is equal to or lower than the first control temperature T1, when the furnace temperature T changes due to opening / closing of the door, etc. The regenerative burner 3 does not cause a chattering operation that repeats ignition and extinguishing, and the flow rate and furnace temperature of the burner can be controlled stably.
Further, according to the heating furnace 10, heat storage is performed when the fuel flow rate of the continuous burner 2 becomes equal to or higher than the flow rate obtained by adding the required minimum flow rate A of the continuous burner 2 and the required minimum flow rate C of the regenerative burner 3. Since the type burner 3 is ignited, it is necessary for each burner to continue combustion stably even when shifting from single control using only the continuous type burner 2 to combined control using the continuous type burner 2 and the heat storage type burner 3. A safe and stable furnace temperature control is possible by ensuring a minimum flow rate.

Note that the furnace temperature control method and furnace temperature control apparatus for a heating furnace according to the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. It is.
For example, the furnace temperature control method and furnace temperature control apparatus for a heating furnace according to the present invention can be applied to any heating furnace in which a continuous burner and a regenerative burner are installed in one control zone. Thus, for example, the heating furnace is not limited to the continuous heating furnace shown in the above embodiment, but is suitable for a relatively high temperature furnace such as a rolling heating furnace, a forging furnace, a heat treatment furnace, a melting furnace, a firing furnace, and a deodorizing furnace. Can be adopted.

Further, the present invention can be applied not only to a newly installed heating furnace but also to remodeling or adding an existing heating furnace.
In other words, when adding a regenerative burner to an existing heating furnace with only a continuous burner installed, or when it is necessary to install a regenerative burner and a continuous burner in one control zone due to equipment space constraints It can employ | adopt suitably. When such an existing heating furnace is remodeled or expanded, it is necessary to control the flow rate of each burner in order to manage one control zone at a desired furnace temperature. However, as explained in the background art, if the conventional technique is excessively combusted with a continuous burner that is inferior to the heat storage burner, there is a problem that the amount of fuel used increases. In addition, when adding a regenerative burner to a heating furnace with a continuous burner, it may be difficult to install a pilot burner due to equipment space constraints. The regenerative burner must be ignited.

  On the other hand, the furnace temperature control method and furnace temperature control apparatus for a heating furnace according to the present invention are based on the total flow rate Q or the furnace temperature T of the fuel flow rate to be supplied to one control zone in one control zone. The furnace temperature T can be controlled by selecting either the independent control for operating only the continuous burner 2 or the combined control for operating the continuous burner 2 and the heat storage burner 3 together. Even at the time of expansion, the target furnace temperature can be achieved while suppressing fuel consumption in one control zone by effective operation of the continuous burner and the regenerative burner.

DESCRIPTION OF SYMBOLS 1 Furnace thermometer 2 Continuous burner 3 Regenerative burner 5 Control part 10 Heating furnace Z1 Pre-tropical zone (one control zone)
Z2 Heating zone (control zone)
Z3 Soaking zone (control zone)
T1 First management temperature T2 Second management temperature TU Target temperature Q Total flow Q1 First management flow (Q1 = ΣA + ΣC)
Q2 Second management flow rate (Q2 = ΣA + ΣD)

Claims (12)

A plurality of control zones capable of independently controlling the furnace temperature, one of the plurality of control zones having a pilot burner and a continuous burner capable of continuous combustion; and a pilot burner A method of controlling the furnace temperature of a heating furnace in which a regenerative burner capable of alternating combustion that repeats combustion and exhaust gas alternately without being installed,
In the one control zone, based on the total flow rate or the furnace temperature of the fuel flow to be supplied to the one control zone, the single control for operating only the continuous burner and the continuous burner and the heat storage burner A furnace temperature control method for a heating furnace, wherein the furnace temperature is controlled by selecting either one of the combined control for operating together.   The furnace temperature control method for a heating furnace according to claim 1, wherein when the furnace temperature is lower than a first management temperature at which the fuel self-ignites, the furnace temperature is controlled by the single control. When the furnace temperature exceeds the first management temperature and the total flow rate of fuel to be supplied to the one control zone is less than the first management flow rate, the furnace temperature is controlled by the single control. And the furnace temperature control method of the heating furnace of Claim 2 which controls a furnace temperature by the said combined control when it is more than a 1st management flow rate.
However, the first management flow rate is the sum of the minimum value of the total fuel flow rate of the continuous burner and the minimum value of the total fuel flow rate of the regenerative burner. When the furnace temperature exceeds the first management temperature, and the total flow rate of the fuel flow to be supplied to the one control zone is not less than the first management flow rate and less than the second management flow rate, the combined use As a control, the furnace temperature is controlled by a first combined control for controlling the fuel flow rate of the regenerative burner within the range from the minimum value to the maximum value while burning the fuel flow rate of the continuous burner at a minimum value. 4. A furnace temperature control method for a heating furnace as described in 3.
However, the second management flow rate is the sum of the minimum value of the total fuel flow rate of the continuous burner and the maximum value of the fuel flow rate of the regenerative burner.   When the furnace temperature exceeds the first management temperature and the total flow rate of the fuel flow to be supplied to the one control zone is equal to or higher than the second management flow rate, The furnace temperature is controlled by the second combined control for controlling the fuel flow rate of the continuous burner from the minimum value to the maximum value while burning the fuel flow rate of the regenerative burner at the maximum value. A furnace temperature control method for a heating furnace. In the heating process before the heating furnace reaches the target temperature of the furnace temperature, until the furnace temperature exceeds the first management temperature and reaches the second management temperature lower than the target temperature, the independent control is performed. Control the furnace temperature,
When the heating furnace is in the temperature raising process, when the furnace temperature exceeds the second management temperature, the furnace temperature is controlled by the combined control,
When the heating furnace is in the process of lowering the target temperature itself, the furnace temperature is controlled by the combined control until the furnace temperature reaches the first management temperature, and the furnace temperature is the first management temperature. The furnace temperature control method for a heating furnace according to any one of claims 2 to 5, wherein when the temperature becomes less than, the furnace temperature is controlled by the single control. A plurality of control zones capable of independently controlling the furnace temperature, one of the plurality of control zones having a pilot burner and a continuous burner capable of continuous combustion; and a pilot burner A furnace temperature control device for controlling the furnace temperature of a heating furnace in which a regenerative burner capable of alternating combustion that alternately repeats combustion and exhaust without having,
A furnace thermometer that detects the furnace temperature in the one control zone, a flow meter for the continuous burner that detects the fuel flow rate of the continuous burner, and a flow rate for the regenerative burner that detects the fuel flow rate of the regenerative burner And the detected values of the furnace thermometer, the flow meter for the continuous burner and the flow meter for the regenerative burner are input, and the combustion state of the continuous burner and the regenerative burner in the one control zone, and A control unit capable of controlling the fuel flow rate,
The control unit operates both the continuous burner and the regenerative burner independently based on a single control for operating only the continuous burner based on the total flow rate of the fuel flow to be supplied to the one control zone or the furnace temperature. A furnace temperature control device that controls the furnace temperature by selecting any one of the combination control to be performed.   The furnace temperature control device according to claim 7, wherein the controller controls the furnace temperature by the single control when the furnace temperature is lower than a first management temperature at which the fuel self-ignites. When the furnace temperature exceeds the first management temperature and the total flow rate of the fuel flow to be supplied to the one control zone is less than the first management flow rate, the control unit performs the single control. The furnace temperature control apparatus according to claim 8, wherein the furnace temperature is controlled by the control, and the furnace temperature is controlled by the combined control when the flow rate is equal to or higher than the first management flow rate.
However, the first management flow rate is the sum of the minimum value of the total fuel flow rate of the continuous burner and the minimum value of the total fuel flow rate of the regenerative burner. The control unit is a case where the furnace temperature exceeds the first management temperature, and the total flow rate of the fuel flow to be supplied to the one control zone is not less than the first management flow rate and less than the second management flow rate. In the combined control, the furnace temperature is controlled by the first combined control in which the fuel flow rate of the regenerative burner is controlled within the range from the minimum value to the maximum value while the fuel flow rate of the continuous burner is burned at the minimum value. The furnace temperature control apparatus of Claim 9 which controls.
However, the second management flow rate is the sum of the minimum value of the total fuel flow rate of the continuous burner and the maximum value of the total fuel flow rate of the regenerative burner.   When the furnace temperature exceeds the first management temperature and the total flow rate of the fuel flow to be supplied to the one control zone is equal to or higher than the second management flow rate, As the combined control, the furnace temperature is controlled by the second combined control that controls the fuel flow rate of the continuous burner from the minimum value to the maximum value while burning the fuel flow rate of the regenerative burner at the maximum value. Item 15. The furnace temperature control device according to Item 10. In the temperature raising process before the heating furnace reaches the target temperature of the furnace temperature, the control unit is configured to wait until the furnace temperature exceeds the first management temperature and reaches a second management temperature lower than the target temperature. The furnace temperature is controlled by the single control,
When the heating furnace is in the temperature raising process, when the furnace temperature exceeds the second management temperature, the furnace temperature is controlled by the combined control,
When the heating furnace is in the process of lowering the target temperature itself, the furnace temperature is controlled by the combined control until the furnace temperature reaches the first management temperature, and the furnace temperature is the first management temperature. The furnace temperature control device according to any one of claims 8 to 11, wherein when the temperature becomes less than, the furnace temperature is controlled by the single control.

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