Industrial furnace combustion control system

Abstract

The utility model belongs to the field of industrial furnace combustion control, and relates to an industrial furnace combustion control system. The combustion control system comprises a fuel gas pipeline and an air pipeline which are connected to the hearth, and the fuel gas pipeline is provided with an air-fuel proportional valve used for adjusting the fuel gas flow to change the ratio of fuel gas to air. One end of the pressure guide branch is connected to the air-fuel proportional valve, and the other end is connected to the air pipeline; a throttling orifice plate is arranged on the pressure guide branch to reduce the impact of high-temperature air on the air-fuel proportional valve; one end of the adjusting branch is connected to the pressure guiding branch, and the other end of the adjusting branch is completely opened to allow high-temperature air in the pressure guiding branch to be discharged into the external environment, so that adjusting proportion fluctuation, caused by air temperature rising, of the air-fuel proportional valve is compensated. Based on the combustion control system provided by the utility model, under the condition that the back pressure of the hearth is continuously changed, the high-temperature combustion-supporting air and the fuel gas can always keep a stable proportion in the combustion process, so that the stability and the timeliness of temperature regulation are enhanced.

Description

Technical Field

[0001] The utility model belongs to the field of industrial furnace combustion control and relates to an industrial furnace combustion control system. Background Art

[0002] Industrial furnaces, as efficient and flexible heating equipment, play a vital role in numerous key industrial sectors, including nonferrous metallurgy, foundry, and solid waste treatment. However, traditional industrial furnaces suffer from numerous deficiencies in combustion control and temperature regulation, which have become a key factor restricting their further development and application.

[0003] Specifically, industrial furnaces currently on the market generally utilize relatively crude combustion control systems, making it difficult to achieve precise temperature and combustion efficiency control. This extensive control approach not only results in significant energy waste but also severely impacts the operational stability and economic efficiency of the industrial furnace. For example, a foundry sand hot-process regenerative fluidized bed roasting furnace must maintain a high temperature environment exceeding approximately 600°C during normal operation. However, during actual operation, the constant fluctuations in furnace pressure, particularly the significant difference between empty and fully loaded furnaces, make it difficult for traditional combustion control systems to cope.

[0004] To ensure stable operation at full load, existing combustion control systems typically set the gas supply pressure at a high level. However, when furnace backpressure is low, this setting causes gas consumption to far exceed the theoretical value, resulting in unnecessary energy waste. Furthermore, most existing combustion control systems rely on changes in furnace temperature to control the combustion air flow rate using a PID controller. These controls proportionally adjust the gas flow rate based on the air flow feedback to control furnace temperature. However, this control method exhibits significant hysteresis. When the combustion air flow rate changes instantaneously, the gas flow rate adjustment often fails to keep pace, significantly compromising temperature control accuracy. For example, when increasing the combustion air flow rate to raise the furnace temperature, the delayed change in gas supply causes the low-temperature combustion air entering the furnace to actually lower the furnace temperature. Furthermore, the increased gas supply increases furnace backpressure, further reducing the gas supply, exacerbating control accuracy issues. Utility Model Content

[0005] In view of this, the purpose of the present invention is to provide an industrial furnace combustion control system that can achieve a stable ratio of high-temperature combustion air and fuel gas during the combustion process when the furnace back pressure continuously changes, thereby enhancing the stability and timeliness of temperature regulation.

[0006] To achieve the above-mentioned objectives, the present invention provides an industrial furnace combustion control system, comprising a gas pipeline and an air pipeline respectively connected to the furnace, wherein an air-fuel ratio valve for adjusting the gas flow to change the ratio of gas to air is provided on the gas pipeline; one end of a pressure-guiding branch is connected to the air-fuel ratio valve, and the other end is connected to the air pipeline; a throttling orifice is provided on the pressure-guiding branch to reduce the impact of high-temperature air in the air pipeline on the air-fuel ratio valve; one end of the regulating branch is connected to the pressure-guiding branch, and the other end is completely open to allow the high-temperature air in the pressure-guiding branch to be discharged into the external environment, thereby compensating for the regulation ratio fluctuation of the air-fuel ratio valve caused by the increase in air temperature.

[0007] Optionally, a first pressure regulating valve and a second pressure regulating valve are provided on the gas pipeline along the gas flow direction; one end of the ignition branch is connected between the first pressure regulating valve and the second pressure regulating valve, and the other end is connected after the air-fuel ratio valve.

[0008] Optionally, a third pressure regulating valve is provided on the ignition branch, one end of the furnace pressure feedback branch is connected to the furnace, and the other end is connected to the second pressure regulating valve and the third pressure regulating valve respectively, so as to feed back the furnace pressure to the gas pipeline and the ignition branch, and dynamically adjust the gas supply pressure through the first pressure regulating valve.

[0009] Optionally, a first solenoid valve and a second solenoid valve are provided between the second pressure regulating valve and the air-fuel ratio valve, and an opening speed of the second solenoid valve is lower than an opening speed of the first solenoid valve.

[0010] Optionally, along the gas flow direction, a third solenoid valve, a fourth solenoid valve and a first manual fine adjustment valve are sequentially arranged after the third pressure regulating valve of the ignition branch, and the opening speed of the fourth solenoid valve is less than the opening speed of the third solenoid valve.

[0011] Optionally, a fifth solenoid valve and a second manual fine adjustment valve are provided on the regulating branch.

[0012] Optionally, a combustion-supporting blower, a heat exchanger and an electric regulating valve are provided on the air pipeline.

[0013] Optionally, along the gas flow direction, the gas pipeline is sequentially provided with a manual ball valve, a filter, a pressure gauge and a flow meter before the first pressure regulating valve.

[0014] Optionally, the pressure-conducting branch is a capillary copper tube with a diameter not exceeding 8 mm, and a portion thereof has a spiral coil.

[0015] The beneficial effects of the present invention are:

[0016] By introducing an air-fuel ratio valve and an improved pressure-guiding branch, the combustion control system provided by the present invention effectively solves the temperature control hysteresis and inaccuracy problems existing in traditional PID control methods. Compared to the PID method of regulating the combustion air flow, the introduction of the air-fuel ratio valve enables the gas flow to match the combustion air flow in real time, which greatly reduces the hysteresis effect during the temperature regulation process, improves the accuracy of temperature control, and reduces gas consumption. When the combustion air flow needs to be increased to raise the furnace temperature, the air-fuel ratio valve can respond quickly and increase the gas flow synchronously, preventing the temperature drop caused by delayed gas supply, thereby avoiding the instability of the furnace temperature caused by delayed changes in gas supply.

[0017] In addition, since the pressure of the air pipeline changes significantly under high temperature conditions, the utility model stabilizes the pressure in the pressure pipe by adding a throttling orifice plate at the connection between the pressure pipe and the air pipeline, further reducing the pressure impact of high-temperature air on the proportional valve and ensuring the stability of the combustion process. At the same time, the utility model also adds a regulating branch with a solenoid valve and a manual fine-adjustment valve to the pressure pipe. This design allows the solenoid valve to be opened and part of the gas to be discharged using the manual fine-adjustment valve when the combustion air temperature exceeds the normal operating temperature, thereby compensating for the problem of proportional valve adjustment inaccuracy caused by temperature increase. This method not only achieves constant proportional control of the air-fuel proportional valve outlet pressure and the air control pressure under the condition of combustion air preheating, but also, compared with the traditional flow feedback control method, each air branch can reduce an air flow meter with temperature and pressure compensation, thereby reducing equipment costs and simplifying the control system.

[0018] Other advantages, objectives, and features of the present invention will be described in detail in the following description and, to some extent, will be apparent to those skilled in the art upon examination and study of the following or may be learned from practice of the present invention. The objectives and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0020] Figure 1 This is a structural diagram of the industrial furnace combustion control system provided by the utility model.

[0021] Figure markings: 1-gas pipeline; 11-filter; 12-flow meter; 13-first pressure regulating valve; 14-second pressure regulating valve; 15-first solenoid valve; 16-second solenoid valve; 17-air-fuel ratio valve; 2-air pipeline; 21-combustion-supporting fan; 22-heat exchanger; 23-electric regulating valve; 3-ignition branch 31-third pressure regulating valve; 32-third solenoid valve; 33-fourth solenoid valve; 34-first manual fine-adjustment valve; 4-pressure guide branch; 41-throttling orifice; 5-regulating branch; 51-fifth solenoid valve; 52-second manual fine-adjustment valve; 6-furnace pressure feedback branch; 7-furnace; 71-burner; 8-manual ball valve; 9-pressure gauge; 10-pressure switch. DETAILED DESCRIPTION

[0022] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. The following embodiments and the features in the embodiments can be combined with each other without conflict.

[0023] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0024] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0025] The utility model aims to provide an industrial furnace combustion control system to solve the problems of unstable combustion control, high energy consumption and delayed temperature regulation caused by furnace back pressure fluctuation in the prior art.

[0026] like Figure 1 As shown, the industrial furnace combustion control system provided by the present invention includes a gas pipeline 1 and an air pipeline 2, both of which are connected to the burner 71 of the furnace 7. An air-fuel ratio valve 17 is provided on the gas pipeline 1 for adjusting the gas flow to change the ratio of gas and air. By introducing the air-fuel ratio valve 17, real-time matching of the gas flow and the combustion air flow is achieved, thereby greatly reducing the lag effect in the temperature adjustment process and improving the accuracy of temperature control. When it is necessary to increase the combustion air flow to increase the furnace temperature, the air-fuel ratio valve 17 can respond quickly and increase the gas flow synchronously to prevent the temperature drop caused by the delay in gas supply, thereby avoiding the instability of the furnace temperature.

[0027] One end of the pressure-guiding branch 4 is connected to the air-fuel ratio valve 17, and the other end is connected to the air line 2. To further optimize the performance of the combustion control system, a throttling orifice 41 is provided on the pressure-guiding branch 4 to reduce the impact of the high-temperature air in the air line 2 on the air-fuel ratio valve 17. The throttling orifice 41 stabilizes the pressure within the pressure-guiding branch, further reducing the pressure impact of the high-temperature air on the ratio valve, ensuring the stability of the combustion process. Furthermore, a regulating branch 5 is provided on the pressure-guiding branch 4. One end of the regulating branch 5 is connected to the pressure-guiding branch 4, and the other end is fully open, allowing the high-temperature air in the pressure-guiding branch 4 to be discharged to the external environment, thereby compensating for fluctuations in the regulation ratio of the air-fuel ratio valve 17 caused by rising air temperature. When the combustion air temperature exceeds the rated operating temperature of the air-fuel ratio valve 17, the regulating branch 5 can discharge some of the high-temperature air, achieving a constant ratio control between the outlet pressure of the air-fuel ratio valve 17 and the air control pressure under preheated combustion air conditions, further improving combustion efficiency and temperature control stability.

[0028] Furthermore, a first pressure-regulating valve 13 and a second pressure-regulating valve 14 are sequentially arranged on the gas pipeline 1 along the direction of gas flow. One end of the ignition branch 3 is connected between the first and second pressure-regulating valves 13 and 14, and the other end is connected to the rear of the air-fuel ratio valve 17. A third pressure-regulating valve 31 is also provided on the ignition branch 3. One end of the furnace pressure feedback branch 6 is connected to the furnace 7, and the other end is connected to the second and third pressure-regulating valves 14 and 31, respectively, to feedback the furnace 7 pressure to the gas pipeline 1 and ignition branch 3. When the back pressure of the furnace 7 fluctuates, the first pressure-regulating valve 13 dynamically adjusts the gas supply pressure to ensure that the pressure of the burner 71 during ignition or normal operation remains within a stable and economical pressure range, thereby reducing gas consumption during the empty furnace heating phase.

[0029] To ensure the safety and reliability of the combustion system, a first solenoid valve 15 and a second solenoid valve 16 are provided between the second pressure regulating valve 14 and the air-fuel ratio valve 17. The opening speed of the second solenoid valve 16 is slower than that of the first solenoid valve 15. Further preferably, the first solenoid valve 15 is a fast-opening solenoid valve with an opening time of less than 1 second and a closing time of less than 1 second, and the second solenoid valve 16 is a slow-opening solenoid valve with an opening time of less than 15 seconds and a closing time of less than 1 second. This ensures that when the gas pipeline 1 system is opened, gas can be slowly supplied to the furnace 7, avoiding excessive furnace pressure fluctuations caused by the instantaneous supply of a large amount of gas into the furnace 7, thereby allowing the burner 71 to ignite smoothly and transition to a stable combustion stage.

[0030] In some possible embodiments, along the gas flow direction, a manual ball valve 8, a filter 11, a pressure gauge 9, and a flowmeter 12 are sequentially installed on the gas pipeline 1 before the first pressure regulating valve 13. A third solenoid valve 32, a fourth solenoid valve 33, and a first manual fine-adjustment valve 34 are sequentially installed on the ignition branch 3 after the third pressure regulating valve 31. A combustion-supporting blower 21, a heat exchanger 22, and an electric regulating valve 23 are installed on the air pipeline 2. A fifth solenoid valve 51 and a second manual fine-adjustment valve 52 are installed on the regulating branch 5 to control the on / off of the regulating branch 5. The opening speed of the fourth solenoid valve 33 is slower than that of the third solenoid valve 32. More preferably, the third solenoid valve 32 is a fast-opening solenoid valve with an opening time of less than 1 second and a closing time of less than 1 second, while the fourth solenoid valve 33 is a slow-opening solenoid valve with an opening time of less than 15 seconds and a closing time of less than 1 second.

[0031] In some possible embodiments, the pressure-conducting branch 4 is a capillary copper tube with a diameter not exceeding 8 mm, which has a spiral coil in part to cooperate with the throttle orifice plate 41 to alleviate the flow impact of high-temperature air and at the same time can reduce the air temperature to a certain extent.

[0032] In some possible implementations, a manual ball valve 8 is provided between the first pressure regulating valve 13 and the second pressure regulating valve 14 of the gas pipeline 1 , and a manual ball valve 8 is provided before the third pressure regulating valve 31 of the ignition branch 3 .

[0033] In some possible embodiments, a pressure gauge 9 is provided between the filter 11 and the flow meter 12 of the gas pipeline 1; a pressure gauge 9 and a pressure switch 10 are provided between the second pressure regulating valve 14 and the first solenoid valve 15 of the gas pipeline 1; a pressure switch 10 is provided between the first solenoid valve 15 and the second solenoid valve 16 of the gas pipeline 1; a pressure gauge 9 and a pressure switch 10 are provided on the pipeline of the gas pipeline 1 after the air-fuel ratio valve 17; a pressure gauge 9 and a pressure switch 10 are provided between the combustion-supporting fan 21 and the heat exchanger 22 of the air pipeline 2.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the utility model.

Claims

1. An industrial furnace combustion control system, characterized by: The invention comprises a gas pipeline (1) and an air pipeline (2) respectively connected to a furnace (7); the gas pipeline (1) is provided with an air-fuel ratio valve (17) for adjusting the gas flow rate to change the ratio of gas to air; one end of a pressure-guiding branch (4) is connected to the air-fuel ratio valve (17), and the other end is connected to the air pipeline (2); wherein, A throttling orifice plate (41) is provided on the pressure-guiding branch (4) to reduce the impact of high-temperature air in the air pipeline (2) on the air-fuel ratio valve (17); One end of the regulating branch (5) is connected to the pressure-conducting branch (4), and the other end is completely open to allow the high-temperature air in the pressure-conducting branch (4) to be discharged to the external environment.

2. The combustion control system according to claim 1, characterized in that: Along the gas flow direction, a first pressure regulating valve (13) and a second pressure regulating valve (14) are provided on the gas pipeline (1); one end of the ignition branch (3) is connected between the first pressure regulating valve (13) and the second pressure regulating valve (14), and the other end is connected to the rear of the air-fuel ratio valve (17).

3. The combustion control system according to claim 2, characterized in that: A third pressure regulating valve (31) is provided on the ignition branch (3); one end of the furnace pressure feedback branch (6) is connected to the furnace (7), and the other end is connected to the second pressure regulating valve (14) and the third pressure regulating valve (31), respectively, so as to feed back the furnace (7) pressure to the gas pipeline (1) and the ignition branch (3), and dynamically adjust the gas supply pressure through the first pressure regulating valve (13).

4. The combustion control system according to claim 2, characterized in that: A first solenoid valve (15) and a second solenoid valve (16) are provided between the second pressure regulating valve (14) and the air-fuel ratio valve (17), and an opening speed of the second solenoid valve (16) is lower than an opening speed of the first solenoid valve (15).

5. The combustion control system according to claim 3, characterized in that: Along the gas flow direction, a third solenoid valve (32), a fourth solenoid valve (33) and a first manual fine adjustment valve (34) are sequentially arranged behind the third pressure regulating valve (31) of the ignition branch (3), and the opening speed of the fourth solenoid valve (33) is lower than the opening speed of the third pressure regulating valve (31).

6. The combustion control system according to any one of claims 1 to 5, characterized in that: The regulating branch (5) is provided with a fifth solenoid valve (51) and a second manual fine-adjustment valve (52).

7. The combustion control system according to any one of claims 1 to 5, characterized in that: The air pipeline (2) is provided with a combustion-supporting blower (21), a heat exchanger (22) and an electric regulating valve (23).

8. The combustion control system according to any one of claims 2 to 5, characterized in that: Along the gas flow direction, the gas pipeline (1) is provided with a manual ball valve (8), a filter (11), a pressure gauge (9) and a flow meter (12) in sequence before the first pressure regulating valve (13).

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