Annealing furnace combustion control system and control method thereof

Abstract

The invention discloses an annealing furnace combustion control system and a control method thereof, and relates to the technical field of annealing furnaces, the annealing furnace combustion control system comprises a first radiation heating unit, a second radiation heating unit, a third radiation heating unit and a fourth radiation heating unit, one end of the first radiant tube is communicated with the first fuel gas outlet and the first oxidizing gas outlet; an inlet of a first heat exchange runner is communicated with the other end of the first radiant tube, and an outlet of a second heat exchange runner is communicated with the first oxidizing gas outlet; the second radiation heating unit comprises a second burner with a second fuel gas outlet and a second oxidizing gas outlet; one end of the second radiant tube is communicated with the second fuel gas outlet and the second oxidizing gas outlet; and the like. The control precision can be improved, the system pressure can be stabilized, the burner is always in the optimal combustion state, then the smoke components are stable, and more energy conservation and environmental protection are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of annealing furnaces, and in particular to an annealing furnace combustion control system and a control method thereof. Background Art

[0002] Annealing furnace is an important equipment in continuous hot-dip galvanizing and continuous annealing production lines, and plays a decisive role in product quality. Most annealing furnaces adopt gas radiation tube heating. The operating principle is that air exchanges heat with flue gas through a heat exchanger and then enters the burner to mix with gas for combustion. The generated flue gas circulates in the radiation tube and heats the annealing furnace by thermal radiation. The flue gas exchanges heat with combustion-supporting air in the heat exchanger at the outlet of the radiation tube for heat recovery and then is discharged into the exhaust pipe. In order to ensure the uniformity and convenient control of the temperature in the furnace, the furnace is divided into several heating areas for temperature control. The main control methods currently used are pulse control and proportional control. Which control method is used has a certain influence on the performance of the entire annealing furnace. With the improvement of energy consumption and environmental protection requirements, higher requirements are also put forward for heating equipment and control systems. The present invention provides a new control system to better play the performance of equipment and achieve the purpose of energy saving and environmental protection. Summary of the invention

[0003] In order to overcome the above-mentioned defects of the prior art, the technical problem to be solved by the embodiments of the present invention is to provide an annealing furnace combustion control system and a control method thereof, which can improve the control accuracy, stabilize the system pressure, and keep the burner in the best combustion state at all times, thereby stabilizing the flue gas composition and being more energy-saving and environmentally friendly.

[0004] The specific technical solution of the embodiment of the present invention is:

[0005] An annealing furnace combustion control system, the annealing furnace combustion control system comprising:

[0006] The first radiation heating unit comprises: a first burner having a first fuel gas outlet and a first oxidizing gas outlet; a first radiation tube, one end of which is connected to the first fuel gas outlet and the first oxidizing gas outlet; a first heat exchanger, comprising a first heat exchange channel and a second heat exchange channel capable of heat exchange, wherein the inlet of the first heat exchange channel is connected to the other end of the first radiation tube, and the outlet of the second heat exchange channel is connected to the first oxidizing gas outlet;

[0007] at least one second radiation heating unit, comprising: a second burner having a second gas outlet and a second oxidizing gas outlet; a second radiation tube, one end of which is connected to the second gas outlet and the second oxidizing gas outlet; a second heat exchanger, comprising a third heat exchange channel and a fourth heat exchange channel capable of heat exchange, the inlet of the third heat exchange channel being connected to the other end of the second radiation tube, and the outlet of the fourth heat exchange channel being connected to the second oxidizing gas outlet; an end of the first radiation tube close to the first burner being connected to an end of the second radiation tube close to the second burner through a first connecting tube; an end of the first radiation tube away from the first burner being connected to an end of the second radiation tube away from the second burner through a second connecting tube;

[0008] A gas input main pipe, wherein a gas flow regulating unit is provided on the gas input main pipe, and an outlet of the gas input main pipe can be connected and disconnected with the first gas outlet and the second gas outlet respectively;

[0009] An oxidizing gas input main pipe, wherein the oxidizing gas input main pipe is provided with an oxidizing gas flow regulating unit, and the outlet of the oxidizing gas input main pipe can be connected and disconnected with the inlet of the second heat exchange flow channel and the inlet of the fourth heat exchange flow channel respectively;

[0010] A smoke exhaust main pipe, wherein the smoke exhaust main pipe can be connected and disconnected with the outlet of the first heat exchange channel and the outlet of the third heat exchange channel respectively.

[0011] Preferably, the annealing furnace combustion control system has a first operation mode, in which the outlet of the gas input main pipe is connected to the first gas outlet, and the outlet of the gas input main pipe is disconnected from the second gas outlet;

[0012] The outlet of the oxidizing gas input main pipe is connected to the inlet of the second heat exchange flow channel, and the outlet of the oxidizing gas input main pipe is disconnected from the inlet of the fourth heat exchange flow channel;

[0013] The smoke exhaust main pipe is communicated with the outlet of the first heat exchange flow channel, and the smoke exhaust main pipe is disconnected from the outlet of the third heat exchange flow channel.

[0014] Preferably, in the first operation mode, the gas flow regulating unit controls the gas input from the gas input main pipe to be one Nth of the gas input when the annealing furnace is burning at full power;

[0015] The oxidizing gas flow regulating unit controls the oxidizing gas input by the oxidizing gas input main pipe to be one Nth of the oxidizing gas input when the annealing furnace is burning at full power;

[0016] N is equal to the number of the second radiant heating units plus the number of the first radiant heating units.

[0017] Preferably, the annealing furnace combustion control system has a second operation mode. In the second operation mode,

[0018] The outlet of the gas input main pipe is disconnected from the first gas outlet, and the outlet of the gas input main pipe is connected to the second gas outlet;

[0019] The outlet of the oxidizing gas input main pipe is disconnected from the inlet of the second heat exchange flow channel, and the outlet of the oxidizing gas input main pipe is connected to the inlet of the fourth heat exchange flow channel;

[0020] The smoke exhaust main pipe is disconnected from the outlet of the first heat exchange channel, and the smoke exhaust main pipe is connected to the outlet of the third heat exchange channel.

[0021] Preferably, in the second operation mode, the gas flow regulating unit controls the gas input from the gas input main pipe to be (N-1) / N of the gas input when the annealing furnace is burning at full power;

[0022] The oxidizing gas flow regulating unit controls the oxidizing gas input from the oxidizing gas input main pipe to be (N-1) / N of the oxidizing gas input when the annealing furnace is burning at full power;

[0023] N is equal to the number of the second radiant heating units plus the number of the first radiant heating units.

[0024] Preferably, the gas flow regulating unit comprises a first gas flow regulating branch and a second gas flow regulating branch connected in parallel;

[0025] The first gas flow regulating branch is provided with a first gas flow regulating valve; the second gas flow regulating branch is provided with a second gas flow regulating valve;

[0026] The maximum flow value of the first gas flow regulating valve is close to one Nth of the gas flow value input when the annealing furnace is burning at full power;

[0027] The maximum flow value of the second gas flow regulating valve is close to (N-1) / N of the gas flow value input when the annealing furnace is burning at full power.

[0028] Preferably, the oxidizing gas flow regulating unit comprises a first oxidizing gas flow regulating branch and a second oxidizing gas flow regulating branch connected in parallel;

[0029] The first oxidizing gas flow regulating branch is provided with a first oxidizing gas flow regulating valve; the second oxidizing gas flow regulating branch is provided with a second oxidizing gas flow regulating valve;

[0030] The maximum flow value of the first oxidizing gas flow regulating valve is close to one Nth of the oxidizing gas flow value input when the annealing furnace is burning at full power;

[0031] The maximum flow rate of the second oxidizing gas flow rate regulating valve is close to (N-1) / N of the oxidizing gas flow rate value input when the annealing furnace is burning at full power.

[0032] Preferably, a first gas flow meter is provided on the first gas flow regulating branch circuit; and a second gas flow meter is provided on the second gas flow regulating branch circuit.

[0033] Preferably, a first oxidizing gas flow meter is provided on the first oxidizing gas flow regulating branch; and a second oxidizing gas flow meter is provided on the second oxidizing gas flow regulating branch.

[0034] Preferably, the annealing furnace combustion control system has a third operation mode, in which the outlet of the gas input main pipe is connected to the first gas outlet, and the outlet of the gas input main pipe is connected to the second gas outlet;

[0035] The outlet of the oxidizing gas input main pipe is connected to the inlet of the second heat exchange flow channel, and the outlet of the oxidizing gas input main pipe is connected to the inlet of the fourth heat exchange flow channel;

[0036] The smoke exhaust main pipe is communicated with the outlet of the first heat exchange channel, and the smoke exhaust main pipe is communicated with the outlet of the third heat exchange channel.

[0037] Preferably, in the third operation mode, the gas flow regulating unit controls the gas input from the gas input main pipe to be the amount of gas input when the annealing furnace is burning at full power;

[0038] The oxidizing gas flow regulating unit controls the oxidizing gas inputted by the oxidizing gas input main pipe to be the oxidizing gas amount inputted when the annealing furnace burns at full power.

[0039] An annealing furnace combustion control method using any of the annealing furnace combustion control systems described above, the annealing furnace combustion control method comprising:

[0040] When the combustion power of the annealing furnace needs to be one-Nth of the annealing furnace at full power, the gas flow rate regulating unit controls the gas input to the gas input main pipe to be one-Nth of the input when the annealing furnace is at full power, and the oxidizing gas flow rate regulating unit controls the oxidizing gas input to the oxidizing gas input main pipe to be one-Nth of the input when the annealing furnace is at full power;

[0041] The outlet of the gas input main pipe is connected to the first gas outlet, the outlet of the gas input main pipe is disconnected from the second gas outlet, the outlet of the oxidizing gas input main pipe is connected to the inlet of the second heat exchange channel, the outlet of the oxidizing gas input main pipe is disconnected from the inlet of the fourth heat exchange channel, the smoke exhaust main pipe is connected to the outlet of the first heat exchange channel, and the smoke exhaust main pipe is disconnected from the outlet of the third heat exchange channel, so that the smoke generated by the combustion of the first radiation heating unit enters the first radiation tube and the second radiation tube respectively, and then the smoke is gathered and enters the first heat exchange channel of the first heat exchanger to exchange heat with the oxidizing gas flowing through the second heat exchange channel, and the smoke after heat exchange is input to the smoke exhaust main pipe for discharge.

[0042] Preferably, the annealing furnace combustion control method comprises:

[0043] When the combustion power of the annealing furnace needs to be (N-1) / N of the annealing furnace at full power combustion, the gas input to the gas input main pipe is controlled by the gas flow regulating unit to be (N-1) / N of the annealing furnace at full power combustion, and the oxidizing gas input to the oxidizing gas input main pipe is controlled by the oxidizing gas flow regulating unit to be (N-1) / N of the annealing furnace at full power combustion;

[0044] The outlet of the gas input main pipe is disconnected from the first gas outlet, the outlet of the gas input main pipe is connected to the second gas outlet, the outlet of the oxidizing gas input main pipe is disconnected from the inlet of the second heat exchange channel, the outlet of the oxidizing gas input main pipe is connected to the inlet of the fourth heat exchange channel, the smoke exhaust main pipe is disconnected from the outlet of the first heat exchange channel, and the smoke exhaust main pipe is connected to the outlet of the third heat exchange channel, so that the smoke generated by the combustion of the second radiation heating unit enters the first radiation tube and the second radiation tube respectively, and then the smoke of the first radiation tube is diverted to enter the third heat exchange channel of the second heat exchanger of the second radiation heating unit to exchange heat with the oxidizing gas flowing through the fourth heat exchange channel, and the smoke after heat exchange is input to the smoke exhaust main pipe for discharge.

[0045] The technical solution of the present invention has the following significant beneficial effects:

[0046] 1. The annealing furnace combustion control system and control method in the present application can connect the first radiant tube of the first radiant heating unit and the second radiant tube of the second radiant heating unit in parallel to share the generated flue gas, thereby making the temperature of the annealing furnace more uniform, avoiding the frequent start and stop of a certain burner, and extending the service life of the equipment. In conjunction with the dual-branch control method of the gas flow regulating unit and the oxidizing gas flow regulating unit, the radiant heating unit of the annealing furnace can be divided into different gears, such as two or three gears, such as high, medium and low.

[0047] 2. The annealing furnace combustion control system and its control method can improve the control accuracy and system response speed, the system pressure is stable, the burning burner can be close to or completely in the best combustion state at each control level, the flue gas composition is stable, and it is more energy-saving and environmentally friendly.

[0048] 3. All radiation tubes of the annealing furnace combustion control system are in a heating state, ensuring the temperature uniformity in the annealing furnace.

[0049] With reference to the following description and drawings, specific embodiments of the present invention are disclosed in detail, indicating the manner in which the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope. Features described and / or shown for one embodiment can be used in one or more other embodiments in the same or similar manner, combined with features in other embodiments, or replace features in other embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the figures are only schematic, used to help understand the present invention, and are not specifically limited to the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to the teachings of the present invention.

[0051] Figure 1 It is a structural schematic diagram of the annealing furnace combustion control system in an embodiment of the present invention;

[0052] Figure 2 It is a structural schematic diagram of a radiation heating unit in an embodiment of the present invention;

[0053] Figure 3 It is a schematic structural diagram of an embodiment of the present invention in which one end of the first radiation tube close to the first burner is connected to one end of the second radiation tube close to the second burner through a first connecting pipe;

[0054] Figure 4 It is a schematic structural diagram of an embodiment of the present invention in which one end of the first radiation tube away from the first burner is connected to one end of the second radiation tube away from the second burner through the second connecting pipe;

[0055] Figure 5 It is a schematic diagram of the flue gas flow of the annealing furnace combustion control system in the first operation mode according to an embodiment of the present invention;

[0056] Figure 6 Schematic diagram of flue gas flow in the second operation mode of the annealing furnace combustion control system according to an embodiment of the present invention.

[0057] Reference numerals in the above drawings:

[0058] 1. First radiation heating unit; 11. First burner; 12. First radiation tube; 13. First heat exchanger; 2. Second radiation heating unit; 21. Second burner; 22. Second radiation tube; 23. Second heat exchanger; 3. Gas input main pipe; 31. Gas flow regulating unit; 311. First gas flow regulating branch; 312. Second gas flow regulating branch; 313. First gas flow regulating valve; 314. Second gas flow regulating valve; 315. First gas flow meter; 316. Second gas flow meter; 4. Oxidizing gas input main pipe; 41. Oxidizing gas flow regulating unit; 411. First oxidizing gas flow regulating branch; 412. Second oxidizing gas flow regulating branch; 4 13. First oxidizing gas flow regulating valve; 414. Second oxidizing gas flow regulating valve; 415. First oxidizing gas flow meter; 416. Second oxidizing gas flow meter; 42. Combustion-supporting fan; 5. Smoke exhaust main pipe; 51. Exhaust fan; 61. First fuel gas input branch pipe; 611. First opening and closing valve; 62. Second fuel gas input branch pipe; 621. Second opening and closing valve; 71. First oxidizing gas input branch pipe; 711. Third opening and closing valve; 72. Second oxidizing gas input branch pipe; 721. Fourth opening and closing valve; 81. First smoke exhaust branch pipe; 811. Fifth opening and closing valve; 82. Second smoke exhaust branch pipe; 821. Sixth opening and closing valve; 91. First connecting pipe; 92. Second connecting pipe. DETAILED DESCRIPTION

[0059] The details of the present invention can be more clearly understood by combining the accompanying drawings and the description of the specific embodiments of the present invention. However, the specific embodiments of the present invention described herein are only used for the purpose of explaining the present invention and cannot be understood as limiting the present invention in any way. Under the guidance of the present invention, technicians can conceive of any possible variations based on the present invention, which should be regarded as belonging to the scope of the present invention. It should be noted that when an element is referred to as "arranged on" another element, it can be directly on another element or there can also be a central element. When an element is considered to be "connected" to another element, it can be directly connected to another element or there may be a central element at the same time. The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be the communication between the two elements, it can be directly connected, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation method.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0061] For an annealing furnace controlled by a pulse control method, each burner maintains the best combustion state when burning, and the heating power is controlled by controlling the burning time of each burner. In order to ensure uniform temperature in the annealing furnace, when not operating at full power, the burners at each position need to be started and closed in turn to prevent the problem of excessive local temperature caused by the burner at a certain position burning all the time. The applicant found that the pulse control method is better when the system is running at high power, but when the system is running at low power, in order to maintain temperature uniformity, each burner needs to be started and stopped frequently. When the number of burners started and stopped is too large, the system pressure will fluctuate greatly, affecting the stability of burner combustion, and also having a great impact on the service life of each valve. If the frequency of burner rotation is too low, it will have a certain impact on the temperature uniformity in the annealing furnace.

[0062] For annealing furnaces with proportional control, the burners in each zone are connected in parallel to the system pipelines, and the system power is controlled by controlling the medium flow in each zone. The power of each burner changes with the change of the zone pipe flow. Since all radiation tubes are in the heating state, the temperature uniformity in the annealing furnace is good. However, the applicant found that the proportional control method cannot ensure that the burner is always in the best combustion state, and the composition of the flue gas generated is relatively unstable, which has a certain impact on energy saving and environmental protection. This phenomenon is more obvious when the control accuracy decreases during low-power operation.

[0063] In order to improve the control accuracy, stabilize the system pressure, keep the burner in the best combustion state, and stabilize the flue gas composition, which is more energy-saving and environmentally friendly, an annealing furnace combustion control system is proposed in this application. Figure 1 It is a structural schematic diagram of the annealing furnace combustion control system in an embodiment of the present invention, Figure 2 is a schematic structural diagram of a radiation heating unit in an embodiment of the present invention, Figure 3 Schematic diagram of the structure in which one end of the first radiation tube close to the first burner is connected to one end of the second radiation tube 22 close to the second burner through the first connecting pipe in the embodiment of the present invention. Figure 4 FIG. 1 is a schematic diagram of a structure in which an end of the first radiation tube away from the first burner is connected to an end of the second radiation tube 22 away from the second burner through a second connecting pipe in an embodiment of the present invention. Figures 1 to 4As shown, the annealing furnace combustion control system may include: a first radiation heating unit 1, including: a first burner 11 with a first fuel gas outlet and a first oxidizing gas outlet; a first radiation tube 12, one end of which is connected to the first fuel gas outlet and the first oxidizing gas outlet; a first heat exchanger 13, including a first heat exchange channel and a second heat exchange channel capable of heat exchange, the inlet of the first heat exchange channel is connected to the other end of the first radiation tube 12, and the outlet of the second heat exchange channel is connected to the first oxidizing gas outlet; at least one second radiation heating unit 2, including: a second burner 21 with a second fuel gas outlet and a second oxidizing gas outlet; a second radiation tube 22, one end of which is connected to the second fuel gas outlet and the second oxidizing gas outlet; a second heat exchanger 23, including a third heat exchange channel and a fourth heat exchange channel capable of heat exchange, the inlet of the third heat exchange channel is connected to the other end of the second radiation tube 22, and the outlet of the fourth heat exchange channel is connected to the first oxidizing gas outlet. The outlet is connected with the second oxidizing gas outlet; the end of the first radiant tube 12 close to the first burner 11 is connected with the end of the second radiant tube 22 close to the second burner 21 through the first connecting pipe 91; the end of the first radiant tube 12 away from the first burner 11 is connected with the end of the second radiant tube 22 away from the second burner 21 through the second connecting pipe 92; the gas input main pipe 3, the gas input main pipe 3 is provided with a gas flow regulating unit 31, and the outlet of the gas input main pipe 3 can be connected and disconnected with the first gas outlet and the second gas outlet respectively; the oxidizing gas input main pipe 4, the oxidizing gas input main pipe 4 is provided with an oxidizing gas flow regulating unit 41, and the outlet of the oxidizing gas input main pipe 4 can be connected and disconnected with the inlet of the second heat exchange flow channel and the inlet of the fourth heat exchange flow channel respectively; the smoke exhaust main pipe 5, the smoke exhaust main pipe 5 can be connected and disconnected with the outlet of the first heat exchange flow channel and the outlet of the third heat exchange flow channel respectively.

[0064] like Figure 1 As shown, the outlet of the gas input main pipe 3 is connected to the first gas outlet through the first gas input branch pipe 61, and the first gas input branch pipe 61 is provided with a first on-off valve 611. The outlet of the gas input main pipe 3 is connected to the second gas outlet through the second gas input branch pipe 62, and the second gas input branch pipe 62 is provided with a second on-off valve 621.

[0065] like Figure 1 As shown, the outlet of the oxidizing gas input main pipe 4 is connected to the inlet of the second heat exchange flow channel through a first oxidizing gas input branch pipe 71, and a third on-off valve 711 is provided on the first oxidizing gas input branch pipe 71. The outlet of the oxidizing gas input main pipe 4 is connected to the inlet of the fourth heat exchange flow channel through a second oxidizing gas input branch pipe 72, and a fourth on-off valve 721 is provided on the second oxidizing gas input branch pipe 72.

[0066] like Figure 1As shown, the smoke exhaust main pipe 5 is connected to the outlet of the first heat exchange flow channel through the first smoke exhaust branch pipe 81, and the first smoke exhaust branch pipe 81 is provided with a fifth opening and closing valve 811. The smoke exhaust main pipe 5 is connected to the outlet of the third heat exchange flow channel through the second smoke exhaust branch pipe 82, and the second smoke exhaust branch pipe 82 is provided with a sixth opening and closing valve 821.

[0067] The annealing furnace combustion control system may have a first operating mode. Figure 5 FIG. 1 is a schematic diagram of the flue gas flow of the annealing furnace combustion control system in the first operation mode according to an embodiment of the present invention. Figure 5 As shown, in the first operation mode, the outlet of the gas input main pipe 3 is connected to the first gas outlet, and the outlet of the gas input main pipe 3 is disconnected from the second gas outlet; the outlet of the oxidizing gas input main pipe 4 is connected to the inlet of the second heat exchange flow channel, and the outlet of the oxidizing gas input main pipe 4 is disconnected from the inlet of the fourth heat exchange flow channel; the smoke exhaust main pipe 5 is connected to the outlet of the first heat exchange flow channel, and the smoke exhaust main pipe 5 is disconnected from the outlet of the third heat exchange flow channel. At this time, the gas flow regulating unit 31 controls the gas inputted by the gas input main pipe 3 to be the part inputted when the annealing furnace is burned at full power, and the oxidizing gas flow regulating unit 41 controls the oxidizing gas inputted by the oxidizing gas input main pipe 4 to be the part inputted when the annealing furnace is burned at full power. Since all the gas and oxidizing gas are outputted and burned at the first burner 11, the first burner can be kept in a state close to the optimal combustion state as much as possible, and the smoke composition is relatively stable, which is more energy-saving and environmentally friendly. At the same time, it is also beneficial to improve the control accuracy and stabilize the system pressure, and only the gas inputted on the gas input main pipe 3 and the oxidizing gas inputted on the oxidizing gas input main pipe 4 need to be adjusted.

[0068] Furthermore, in the first operating mode, the gas flow regulating unit 31 controls the gas inputted by the gas input main pipe 3 to be one-Nth of the gas inputted when the annealing furnace is burning at full power; the oxidizing gas flow regulating unit 41 controls the oxidizing gas inputted by the oxidizing gas input main pipe 4 to be one-Nth of the gas inputted when the annealing furnace is burning at full power. N is equal to the number of the second radiant heating units 2 plus the number of the first radiant heating units 1. The above method is particularly suitable for when the annealing furnace is in low-power operation. In the above state, the flow rate of the gas outputted and burned by the first burner 11 and the flow rate of the oxidizing gas are exactly the same as the flow rate of the gas outputted and burned by the first burner 11 when the annealing furnace is burning at full power and the flow rate of the oxidizing gas. Therefore, the first burner 11 is in a completely optimal combustion state.

[0069] As a possibility, the annealing furnace combustion control system may have a second operation mode. Figure 6 FIG. 1 is a schematic diagram of the flue gas flow of the annealing furnace combustion control system in the second operation mode according to an embodiment of the present invention. Figure 6As shown, in the second operating mode, the outlet of the gas input main pipe 3 is disconnected from the first gas outlet, and the outlet of the gas input main pipe 3 is connected to the second gas outlet; the outlet of the oxidizing gas input main pipe 4 is disconnected from the inlet of the second heat exchange channel, and the outlet of the oxidizing gas input main pipe 4 is connected to the inlet of the fourth heat exchange channel; the smoke exhaust main pipe 5 is disconnected from the outlet of the first heat exchange channel, and the smoke exhaust main pipe 5 is connected to the outlet of the third heat exchange channel.

[0070] At this time, the gas flow regulating unit 31 controls the gas inputted by the gas input main pipe 3 to be the part inputted when the annealing furnace is burning at full power, and the oxidizing gas flow regulating unit 41 controls the oxidizing gas inputted by the oxidizing gas input main pipe 4 to be the part inputted when the annealing furnace is burning at full power. Since all the gas and oxidizing gas are outputted and burned at the second burner 21 respectively, the second burner 21 can be kept as close to the optimal combustion state as possible, the smoke composition is relatively stable, and it is more energy-saving and environmentally friendly. At the same time, it is also beneficial to improve the control accuracy and stabilize the system pressure, and it is only necessary to adjust the gas inputted on the gas input main pipe 3 and the oxidizing gas inputted on the oxidizing gas input main pipe 4.

[0071] Further, in the second operation mode, the gas flow regulating unit 31 controls the gas inputted by the gas input main pipe 3 to be (N-1) / N inputted when the annealing furnace is burning at full power; the oxidizing gas flow regulating unit 41 controls the oxidizing gas inputted by the oxidizing gas input main pipe 4 to be (N-1) / N inputted when the annealing furnace is burning at full power; N is equal to the number of the second radiation heating units 2 plus the number of the first radiation heating units 1. The above method is particularly suitable for when the annealing furnace is in medium power operation. In the above state, the flow rate of the gas outputted and burned by the second burner 21 and the flow rate of the oxidizing gas are exactly the same as the flow rate of the gas outputted and burned by the second burner 21 when the annealing furnace is burning at full power and the flow rate of the oxidizing gas, therefore, the second burner 21 is in a completely optimal combustion state.

[0072] In order to make it more convenient for the gas flow regulating unit 31 to regulate the gas flow of the gas input main pipe 3, as feasible, the gas flow regulating unit 31 may include a first gas flow regulating branch 311 and a second gas flow regulating branch 312 connected in parallel; a first gas flow regulating valve 313 is provided on the first gas flow regulating branch 311; and a second gas flow regulating valve 314 is provided on the second gas flow regulating branch 312. The maximum flow value of the first gas flow regulating valve 313 is close to one Nth of the gas flow value input when the annealing furnace is burning at full power; the maximum flow value of the second gas flow regulating valve 314 is close to (N-1) / N of the gas flow value input when the annealing furnace is burning at full power. In the above manner, in the first operating mode, the first gas flow regulating valve 313 is fully opened and the second gas flow regulating valve 314 is fully closed. In the second operating mode, the first gas flow regulating valve 313 is fully closed and the second gas flow regulating valve 314 is fully opened.

[0073] In order to more accurately control the flow on the branch, such as Figure 1 As shown, a first gas flow meter 315 is provided on the first gas flow regulating branch 311, and a second gas flow meter 316 is provided on the second gas flow regulating branch 312. The first gas flow regulating valve 313 and the second gas flow regulating valve 314 can be fine-tuned by the gas flow meter.

[0074] Similarly, in order to make it more convenient for the oxidation gas flow regulating unit 41 to regulate the oxidation gas flow of the oxidation gas input main pipe 4, as feasible, the oxidation gas flow regulating unit 41 includes a first oxidation gas flow regulating branch 411 and a second oxidation gas flow regulating branch 412 connected in parallel. The first oxidation gas flow regulating branch 411 is provided with a first oxidation gas flow regulating valve 413; the second oxidation gas flow regulating branch 412 is provided with a second oxidation gas flow regulating valve 414; the maximum flow value of the first oxidation gas flow regulating valve 413 is close to one Nth of the oxidation gas flow value input when the annealing furnace is burning at full power; the maximum flow value of the second oxidation gas flow regulating valve 414 is close to (N-1) / N of the oxidation gas flow value input when the annealing furnace is burning at full power. In the above manner, in the first operating mode, the first oxidation gas flow regulating valve 413 is fully opened and the second oxidation gas flow regulating valve 414 is fully closed. In the second operating mode, the first oxidation gas flow regulating valve 413 is fully closed and the second oxidation gas flow regulating valve 414 is fully opened.

[0075] In order to more accurately control the flow on the branch, such as Figure 1As shown, a first oxidizing gas flow meter 415 is provided on the first oxidizing gas flow regulating branch 411, and a second oxidizing gas flow meter 416 is provided on the second oxidizing gas flow regulating branch 412. The first oxidizing gas flow regulating valve 413 and the second oxidizing gas flow regulating valve 414 can be fine-tuned by the oxidizing gas flow meter.

[0076] The combustion control system of the annealing furnace can have a third operation mode. In the third operation mode, the outlet of the gas input main pipe 3 is connected to the first gas outlet, and the outlet of the gas input main pipe 3 is connected to the second gas outlet; the outlet of the oxidizing gas input main pipe 4 is connected to the inlet of the second heat exchange flow channel, and the outlet of the oxidizing gas input main pipe 4 is connected to the inlet of the fourth heat exchange flow channel; the smoke exhaust main pipe 5 is connected to the outlet of the first heat exchange flow channel, and the smoke exhaust main pipe 5 is connected to the outlet of the third heat exchange flow channel. In the third operation mode, the gas flow regulating unit 31 controls the gas inputted by the gas input main pipe 3 to be the gas amount inputted when the annealing furnace is burned at full power; the oxidizing gas flow regulating unit 41 controls the oxidizing gas inputted by the oxidizing gas input main pipe 4 to be the oxidizing gas amount inputted when the annealing furnace is burned at full power. In the third operation mode, the first gas flow regulating valve 313 is fully opened, the second gas flow regulating valve 314 is fully opened, the first oxidizing gas flow regulating valve 413 is fully opened, and the second oxidizing gas flow regulating valve 414 is fully opened.

[0077] As feasible, Figure 1 As shown, a combustion-supporting fan 42 may be provided on the oxidizing gas input main pipe 4 to blow the oxidizing gas into the oxidizing gas input main pipe 4 and drive the oxidizing gas to flow. An exhaust fan 51 is provided on the smoke exhaust main pipe 5 to help exhaust the smoke generated by the annealing furnace.

[0078] In a specific embodiment, Figure 1 As shown, there is one first radiation heating unit 1 and two second radiation heating units 2. Thus, in the first operating mode, the power of the annealing furnace is one third of the full power, and the annealing furnace is in low-grade heating. In the second operating mode, the power of the annealing furnace is two thirds of the full power, and the annealing furnace is in medium-grade heating. In the third operating mode, the power of the annealing furnace is full power, and the annealing furnace is in high-grade heating.

[0079] The present application also proposes an annealing furnace combustion control method, which can be applied to any of the above-mentioned annealing furnace combustion control systems, and can also be applied to other feasible annealing furnace combustion control systems. The annealing furnace combustion control method can include the following steps:

[0080] When the combustion power of the annealing furnace needs to be one-Nth of the annealing furnace's full-power combustion, the gas flow regulating unit 31 controls the gas input into the gas input main pipe 3 to be one-Nth of the input when the annealing furnace is burning at full power, and the oxidizing gas flow regulating unit 41 controls the oxidizing gas input into the oxidizing gas main pipe 4 to be one-Nth of the input when the annealing furnace is burning at full power.

[0081] The outlet of the gas input main pipe 3 is connected to the first gas outlet, the outlet of the gas input main pipe 3 is disconnected from the second gas outlet, the outlet of the oxidizing gas input main pipe 4 is connected to the inlet of the second heat exchange channel, the outlet of the oxidizing gas input main pipe 4 is disconnected from the inlet of the fourth heat exchange channel, the smoke exhaust main pipe 5 is connected to the outlet of the first heat exchange channel, and the smoke exhaust main pipe 5 is disconnected from the outlet of the third heat exchange channel, so that the smoke generated by the combustion of the first radiation heating unit 1 enters the first radiation tube 12 and the second radiation tube 22 respectively, and then the smoke is gathered and enters the first heat exchange channel of the first heat exchanger 13 to exchange heat with the oxidizing gas flowing through the second heat exchange channel, and the smoke after heat exchange is input to the smoke exhaust main pipe 5 for discharge.

[0082] When the combustion power of the annealing furnace needs to be (N-1) / N of the annealing furnace when it is burning at full power, the gas flow regulating unit 31 controls the gas input into the gas input main pipe 3 to be (N-1) / N of the input when the annealing furnace is burning at full power, and the oxidizing gas flow regulating unit 41 controls the oxidizing gas input into the oxidizing gas main pipe 4 to be (N-1) / N of the input when the annealing furnace is burning at full power.

[0083] The outlet of the gas input main pipe 3 is disconnected from the first gas outlet, the outlet of the gas input main pipe 3 is connected to the second gas outlet, the outlet of the oxidizing gas input main pipe 4 is disconnected from the inlet of the second heat exchange flow channel, the outlet of the oxidizing gas input main pipe 4 is connected to the inlet of the fourth heat exchange flow channel, the smoke exhaust main pipe 5 is disconnected from the outlet of the first heat exchange flow channel, and the smoke exhaust main pipe 5 is connected to the outlet of the third heat exchange flow channel, so that the smoke generated by the combustion of the second radiation heating unit 2 enters the first radiation tube 12 and the second radiation tube 22 respectively, and then the smoke of the first radiation tube 12 is diverted to enter the third heat exchange flow channel of the second heat exchanger 23 of the second radiation heating unit 2 to exchange heat with the oxidizing gas flowing through the fourth heat exchange flow channel, and the smoke after heat exchange is input to the smoke exhaust main pipe 5 for discharge.

[0084] When the combustion power of the annealing furnace needs to be full-power combustion of the annealing furnace, the gas input into the gas input main pipe 3 is controlled by the gas flow regulating unit 31 to be the input amount when the annealing furnace is full-power combustion, and the oxidizing gas input into the oxidizing gas main pipe 4 is controlled by the oxidizing gas flow regulating unit 41 to be the input amount when the annealing furnace is full-power combustion.

[0085] The outlet of the gas input main pipe 3 is connected to the first gas outlet, the outlet of the gas input main pipe 3 is connected to the second gas outlet, the outlet of the oxidizing gas input main pipe 4 is connected to the inlet of the second heat exchange flow channel, the outlet of the oxidizing gas input main pipe 4 is connected to the inlet of the fourth heat exchange flow channel, the smoke exhaust main pipe 5 is connected to the outlet of the first heat exchange flow channel, and the smoke exhaust main pipe 5 is connected to the outlet of the third heat exchange flow channel, so that the smoke generated by the combustion of the first radiation heating unit 1 enters the first radiation tube 12, and the smoke generated by the combustion of the second radiation heating unit 2 enters the second radiation tube 22, and then the smoke of the first radiation tube 12 enters the first heat exchange flow channel of the first heat exchanger 13 of the first radiation heating unit 1 to exchange heat with the oxidizing gas flowing through the second heat exchange flow channel, and the smoke after heat exchange is input to the smoke exhaust main pipe 5 for discharge, the smoke of the second radiation tube 22 enters the third heat exchange flow channel of the second heat exchanger 23 of the second radiation heating unit 2 to exchange heat with the oxidizing gas flowing through the fourth heat exchange flow channel, and the smoke after heat exchange is input to the smoke exhaust main pipe 5 for discharge.

[0086] The annealing furnace combustion control system and control method in the present application can connect the first radiant tube 12 of the first radiant heating unit 1 and the second radiant tube 22 of the second radiant heating unit 2 in parallel to share the generated flue gas, so that the temperature of the annealing furnace is more uniform, avoiding the frequent start and stop of a certain burner, and extending the service life of the equipment. In conjunction with the dual-branch control method of the gas flow regulating unit 31 and the oxidizing gas flow regulating unit 41, the radiant heating units of the annealing furnace can be divided into different gears, such as the second gear or the third gear, such as high, medium and low gears. The annealing furnace combustion control system and control method can improve the control accuracy and system response speed, the system pressure is stable, the burning burner can be close to or completely in the optimal combustion state at each gear control, the flue gas composition is stable, and it is more energy-saving and environmentally friendly. In addition, all the radiant tubes of the annealing furnace combustion control system are in a heating state, which ensures the temperature uniformity in the annealing furnace.

[0087] All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for various purposes. The term "consisting essentially of ... " describing a combination should include determined elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel features of the combination. The use of the terms "comprising" or "including" to describe the combination of elements, ingredients, parts or steps here also contemplates the implementation method consisting essentially of these elements, ingredients, parts or steps. Here, by using the term "may", it is intended to illustrate that any attribute described that "may" includes is optional. Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "one" used to describe an element, ingredient, part or step is not said to exclude other elements, ingredients, parts or steps.

[0088] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. The above embodiments are only for illustrating the technical concept and features of the present invention. The purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An annealing furnace combustion control system, characterized in that: The annealing furnace combustion control system comprises: The first radiation heating unit comprises: a first burner having a first fuel gas outlet and a first oxidizing gas outlet; a first radiation tube, one end of which is connected to the first fuel gas outlet and the first oxidizing gas outlet; a first heat exchanger, comprising a first heat exchange channel and a second heat exchange channel capable of heat exchange, wherein the inlet of the first heat exchange channel is connected to the other end of the first radiation tube, and the outlet of the second heat exchange channel is connected to the first oxidizing gas outlet; at least one second radiation heating unit, comprising: a second burner having a second gas outlet and a second oxidizing gas outlet; a second radiation tube, one end of which is connected to the second gas outlet and the second oxidizing gas outlet; a second heat exchanger, comprising a third heat exchange channel and a fourth heat exchange channel capable of heat exchange, the inlet of the third heat exchange channel being connected to the other end of the second radiation tube, and the outlet of the fourth heat exchange channel being connected to the second oxidizing gas outlet; an end of the first radiation tube close to the first burner being connected to an end of the second radiation tube close to the second burner through a first connecting tube; an end of the first radiation tube away from the first burner being connected to an end of the second radiation tube away from the second burner through a second connecting tube; A gas input main pipe, wherein a gas flow regulating unit is provided on the gas input main pipe, and an outlet of the gas input main pipe can be connected and disconnected with the first gas outlet and the second gas outlet respectively; An oxidizing gas input main pipe, wherein the oxidizing gas input main pipe is provided with an oxidizing gas flow regulating unit, and the outlet of the oxidizing gas input main pipe can be connected and disconnected with the inlet of the second heat exchange flow channel and the inlet of the fourth heat exchange flow channel respectively; A smoke exhaust main pipe, wherein the smoke exhaust main pipe can be connected and disconnected with the outlet of the first heat exchange channel and the outlet of the third heat exchange channel respectively.

2. The annealing furnace combustion control system according to claim 1, characterized in that: The annealing furnace combustion control system has a first operation mode, in which the outlet of the gas input main pipe is connected to the first gas outlet, and the outlet of the gas input main pipe is disconnected from the second gas outlet; The outlet of the oxidizing gas input main pipe is connected to the inlet of the second heat exchange flow channel, and the outlet of the oxidizing gas input main pipe is disconnected from the inlet of the fourth heat exchange flow channel; The smoke exhaust main pipe is communicated with the outlet of the first heat exchange flow channel, and the smoke exhaust main pipe is disconnected from the outlet of the third heat exchange flow channel.

3. The annealing furnace combustion control system according to claim 2, characterized in that: In the first operation mode, the gas flow regulating unit controls the gas input by the gas input main pipe to be one Nth of the gas input when the annealing furnace is burning at full power; The oxidizing gas flow regulating unit controls the oxidizing gas input by the oxidizing gas input main pipe to be one Nth of the oxidizing gas input when the annealing furnace is burning at full power; N is equal to the number of the second radiant heating units plus the number of the first radiant heating units.

4. The annealing furnace combustion control system according to claim 1, characterized in that: The annealing furnace combustion control system has a second operation mode. In the second operation mode, The outlet of the gas input main pipe is disconnected from the first gas outlet, and the outlet of the gas input main pipe is connected to the second gas outlet; The outlet of the oxidizing gas input main pipe is disconnected from the inlet of the second heat exchange flow channel, and the outlet of the oxidizing gas input main pipe is connected to the inlet of the fourth heat exchange flow channel; The smoke exhaust main pipe is disconnected from the outlet of the first heat exchange channel, and the smoke exhaust main pipe is connected to the outlet of the third heat exchange channel.

5. The annealing furnace combustion control system according to claim 4, characterized in that: In the second operation mode, the gas flow regulating unit controls the gas input from the gas input main pipe to be (N-1) / N of the gas input when the annealing furnace is burning at full power; The oxidizing gas flow regulating unit controls the oxidizing gas input from the oxidizing gas input main pipe to be (N-1) / N of the oxidizing gas input when the annealing furnace is burning at full power; N is equal to the number of the second radiant heating units plus the number of the first radiant heating units.

6. The annealing furnace combustion control system according to claim 2 or 4, characterized in that: The gas flow regulating unit comprises a first gas flow regulating branch and a second gas flow regulating branch connected in parallel; The first gas flow regulating branch is provided with a first gas flow regulating valve; the second gas flow regulating branch is provided with a second gas flow regulating valve; The maximum flow value of the first gas flow regulating valve is close to one Nth of the gas flow value input when the annealing furnace is burning at full power; The maximum flow value of the second gas flow regulating valve is close to (N-1) / N of the gas flow value input when the annealing furnace is burning at full power.

7. The annealing furnace combustion control system according to claim 2 or 4, characterized in that: The oxidizing gas flow regulating unit comprises a first oxidizing gas flow regulating branch and a second oxidizing gas flow regulating branch connected in parallel; The first oxidizing gas flow regulating branch is provided with a first oxidizing gas flow regulating valve; the second oxidizing gas flow regulating branch is provided with a second oxidizing gas flow regulating valve; The maximum flow value of the first oxidizing gas flow regulating valve is close to one Nth of the oxidizing gas flow value input when the annealing furnace is burning at full power; The maximum flow rate of the second oxidizing gas flow rate regulating valve is close to (N-1) / N of the oxidizing gas flow rate value input when the annealing furnace is burning at full power.

8. The annealing furnace combustion control system according to claim 6, characterized in that: The first gas flow regulating branch is provided with a first gas flow meter; the second gas flow regulating branch is provided with a second gas flow meter.

9. The annealing furnace combustion control system according to claim 7, characterized in that: The first oxidizing gas flow regulating branch is provided with a first oxidizing gas flow meter; the second oxidizing gas flow regulating branch is provided with a second oxidizing gas flow meter.

10. The annealing furnace combustion control system according to claim 1, characterized in that: The annealing furnace combustion control system has a third operation mode, in which the outlet of the gas input main pipe is connected to the first gas outlet, and the outlet of the gas input main pipe is connected to the second gas outlet; The outlet of the oxidizing gas input main pipe is connected to the inlet of the second heat exchange flow channel, and the outlet of the oxidizing gas input main pipe is connected to the inlet of the fourth heat exchange flow channel; The smoke exhaust main pipe is communicated with the outlet of the first heat exchange channel, and the smoke exhaust main pipe is communicated with the outlet of the third heat exchange channel.

11. The annealing furnace combustion control system according to claim 10, characterized in that: In the third operation mode, the gas flow regulating unit controls the gas input from the gas input main pipe to be the amount of gas input when the annealing furnace is burning at full power; The oxidizing gas flow regulating unit controls the oxidizing gas inputted from the oxidizing gas input main pipe to be the oxidizing gas amount inputted when the annealing furnace burns at full power.

12. An annealing furnace combustion control method using the annealing furnace combustion control system as claimed in claim 1, characterized in that: The annealing furnace combustion control method comprises: When the combustion power of the annealing furnace needs to be one-Nth of the annealing furnace at full power, the gas flow rate regulating unit controls the gas input to the gas input main pipe to be one-Nth of the input when the annealing furnace is at full power, and the oxidizing gas flow rate regulating unit controls the oxidizing gas input to the oxidizing gas input main pipe to be one-Nth of the input when the annealing furnace is at full power; The outlet of the gas input main pipe is connected to the first gas outlet, the outlet of the gas input main pipe is disconnected from the second gas outlet, the outlet of the oxidizing gas input main pipe is connected to the inlet of the second heat exchange channel, the outlet of the oxidizing gas input main pipe is disconnected from the inlet of the fourth heat exchange channel, the smoke exhaust main pipe is connected to the outlet of the first heat exchange channel, and the smoke exhaust main pipe is disconnected from the outlet of the third heat exchange channel, so that the smoke generated by the combustion of the first radiation heating unit enters the first radiation tube and the second radiation tube respectively, and then the smoke is gathered and enters the first heat exchange channel of the first heat exchanger to exchange heat with the oxidizing gas flowing through the second heat exchange channel, and the smoke after heat exchange is input to the smoke exhaust main pipe for discharge.

13. The annealing furnace combustion control method according to claim 12, characterized in that: The annealing furnace combustion control method comprises: When the combustion power of the annealing furnace needs to be (N-1) / N of the annealing furnace at full power combustion, the gas input to the gas input main pipe is controlled by the gas flow regulating unit to be (N-1) / N of the annealing furnace at full power combustion, and the oxidizing gas input to the oxidizing gas input main pipe is controlled by the oxidizing gas flow regulating unit to be (N-1) / N of the annealing furnace at full power combustion; The outlet of the gas input main pipe is disconnected from the first gas outlet, the outlet of the gas input main pipe is connected to the second gas outlet, the outlet of the oxidizing gas input main pipe is disconnected from the inlet of the second heat exchange flow channel, the outlet of the oxidizing gas input main pipe is connected to the inlet of the fourth heat exchange flow channel, the smoke exhaust main pipe is disconnected from the outlet of the first heat exchange flow channel, and the smoke exhaust main pipe is connected to the outlet of the third heat exchange flow channel, so that the smoke generated by the combustion of the second radiation heating unit enters the first radiation tube and the second radiation tube respectively, and then the smoke of the first radiation tube is diverted to enter the third heat exchange flow channel of the second heat exchanger of the second radiation heating unit to exchange heat with the oxidizing gas flowing through the fourth heat exchange flow channel, and the smoke after heat exchange is input to the smoke exhaust main pipe for discharge.

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