Automatic temperature control system for combustion furnace

Abstract

A kind of combustion furnace temperature automatic control system, including hearth, hearth one side is built with refractory brick wall, and high-temperature decomposition area is formed in refractory brick wall, the other side of the hearth is equipped with exhaust gas heat exchanger and hot air heat exchanger in sequence, high-temperature flue gas after high-temperature decomposition area is led to exhaust gas heat exchanger and hot air heat exchanger, hot air heat exchanger side is equipped with flue gas pipeline, and exhaust fan is installed on flue gas pipeline, the two sides of exhaust gas heat exchanger and hot air heat exchanger are formed with exhaust gas passage and hot air passage respectively with hearth side wall, the other side of the hearth is equipped with exhaust fan and fresh air fan respectively leading to exhaust gas passage and hot air passage, partition is installed in the exhaust gas passage and hot air passage, valve is processed on partition, valve surface is provided with valve plate, the side of valve plate is connected with shaft, the top of the hearth is provided with pneumatic actuator, and pneumatic actuator is connected with the side of valve plate with shaft, control valve plate opening and closing, realize exhaust gas preheating temperature and hot air temperature accurate control.

Description

Technical Field

[0001] This utility model relates to the field of combustion furnace technology, specifically to an automatic temperature control system for a combustion furnace. Background Technology

[0002] Direct-fired combustion furnaces are used to treat organic waste gas generated during the drying process. The waste gas is first preheated to its decomposition temperature, typically ≥480℃, and then further heated in the furnace to above 780℃ for high-temperature decomposition. Finally, the waste heat is recovered through a waste heat recovery system (hot air or thermal oil heat exchanger) to heat the air for use in the drying process. It is a widely used environmentally friendly and energy-saving device. It mainly consists of a furnace, a waste gas preheater, and a hot air heat exchanger. The high-temperature decomposed flue gas passes through the outside of the tubes of the waste gas heat exchanger, heating the organic waste gas inside the tubes. The high-temperature flue gas passes through the outside of the tubes of the hot air heat exchanger, heating the ambient-temperature fresh air inside the tubes, becoming high-temperature hot air for the next process. It is widely used in industries such as insulation materials, copper-clad laminates, and decorative paper.

[0003] Currently, organic waste gas must reach a certain preheating temperature after being preheated by a waste gas preheater; otherwise, it cannot be fully decomposed in the furnace. In actual production, the amount of organic waste gas varies greatly due to factors such as the type of product, the type of adhesive, and the speed of the machine. The heat exchange area of ​​the waste gas preheater in a direct-fired combustion furnace is fixed (designed based on the maximum waste gas volume), which often leads to overheating of the waste gas during preheating. Therefore, it is necessary to control the waste gas preheating temperature. The existing control mode uses a variable frequency drive (VFD) for the exhaust gas fan's drive motor. When the exhaust gas preheating temperature exceeds the set value, the exhaust gas fan automatically increases its speed, thereby increasing the exhaust gas flow rate to achieve temperature control. However, with the increased flow rate, excess cold air enters, reducing the concentration of organic waste gas and causing the furnace temperature to drop below the set temperature. To maintain the set furnace temperature, natural gas consumption needs to be increased, thus increasing the equipment's operating costs and making it extremely uneconomical. The hot air heat exchanger also suffers from the same problem. When the high-temperature hot air exceeds the set temperature, the increased airflow also hinders production control. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide an automatic control system for combustion furnace temperature, which addresses the shortcomings of the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: An automatic temperature control system for a combustion furnace includes a furnace chamber. One side of the furnace chamber is lined with a refractory brick wall, forming a high-temperature decomposition zone in the middle of the refractory brick wall. A waste gas heat exchanger and a hot air heat exchanger are sequentially installed on the other side of the furnace chamber. High-temperature flue gas from the decomposition zone flows to the waste gas heat exchanger and the hot air heat exchanger. A flue gas duct is installed on the side of the hot air heat exchanger, and an exhaust fan is installed on the flue gas duct. Waste gas passages and hot air passages are formed between the waste gas heat exchanger and the furnace sidewall on both sides, respectively. A waste gas fan and a fresh air fan are installed on the outside of the furnace chamber, respectively leading to the waste gas passages and the hot air passages. Baffles are installed in the waste gas passages and the hot air passages, and valves are machined on the baffles. A valve plate is provided on the surface of the valve, and a shaft is connected to the side of the valve plate. A pneumatic actuator is installed above the furnace chamber, and the pneumatic actuator is connected to the shaft on the side of the valve plate to control the opening and closing of the valve plate.

[0006] Furthermore, a baffle is provided at the junction of the waste gas heat exchanger and the hot air heat exchanger to connect with the side wall of the furnace.

[0007] Furthermore, a high-temperature exhaust gas channel is formed between the side of the refractory brick wall and the side of the furnace. A natural gas burner is installed on the side of the high-temperature exhaust gas channel, and the outlet of the exhaust gas channel is connected to the high-temperature exhaust gas channel.

[0008] Furthermore, a hot air outlet pipe is installed on the other side outside the furnace, and the outlet of the hot air passage is connected to the hot air outlet pipe.

[0009] Furthermore, a bracket is installed above the furnace chamber, a pneumatic actuator is connected to the bracket, a drive shaft is connected to the pneumatic actuator, and the drive shaft is connected to the bracket via bearings. Two upper and lower bearing brackets are connected to the partition plate, and the shaft is connected to the upper and lower bearing brackets via bearings. One end of the drive shaft passes through the furnace chamber and is connected to the shaft via a coupling.

[0010] Furthermore, the pneumatic actuator is a rotary cylinder.

[0011] Furthermore, an angle plate is installed on the bracket, and a scale is set on the angle plate. A pointer is installed on the drive shaft, and the pointer is pointing towards the scale on the angle plate.

[0012] Compared with the prior art, the automatic temperature control system for a combustion furnace of this utility model can achieve precise control of exhaust gas preheating temperature and hot air temperature by adding a gate-type regulating valve plate and controlling the valve plate angle. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the valve plate installation structure of this utility model; Among them, 1. Furnace, 2. Refractory brick wall, 3. High-temperature decomposition zone, 4. High-temperature exhaust gas passage, 5. Exhaust gas heat exchanger, 6. Hot air heat exchanger, 7. Flue gas duct, 8. Exhaust fan, 9. Baffle, 10. Exhaust gas passage, 11. Hot air passage, 12. Exhaust gas fan, 13. Fresh air fan, 14. Natural gas burner, 15. Hot air outlet duct, 16. Partition, 17. Valve plate, 18. Shaft, 19. Pneumatic actuator, 20. Bracket, 21. Drive shaft, 22. Bearing bracket, 23. Coupling, 24. Angle plate, 25. Pointer. Detailed Implementation

[0014] The technical solutions in the embodiments of this utility model will be clearly and completely described below.

[0015] like Figure 1 and Figure 2 As shown, an automatic temperature control system for a combustion furnace includes a furnace chamber 1. One side of the furnace chamber 1 is lined with a refractory brick wall 2, and a high-temperature decomposition zone 3 is formed in the middle of the refractory brick wall 2. A high-temperature exhaust gas channel 4 is formed between the side wall of the furnace chamber 1 and the side wall of the furnace chamber 1. An exhaust gas heat exchanger 5 and a hot air heat exchanger 6 are installed sequentially on the other side of the furnace chamber 1. The high-temperature flue gas after decomposition in the high-temperature decomposition zone 3 is directed to the exhaust gas heat exchanger 5 and the hot air heat exchanger 6. A flue gas duct 7 is installed on the side of the hot air heat exchanger 6, and an exhaust fan 8 is installed on the flue gas duct 7. After the high-temperature flue gas exchanges heat with the exhaust gas heat exchanger 5 and the hot air heat exchanger 6, the exhaust fan 8 discharges the flue gas from the flue gas duct 7.

[0016] A baffle 9 is provided at the junction of the waste gas heat exchanger 5 and the hot air heat exchanger 6. The baffle 9 is connected to the side wall of the furnace 1. The baffle 9 forms a waste gas passage 10 and a hot air passage 11 between the two sides of the waste gas heat exchanger 5 and the hot air heat exchanger 6 and the side wall of the furnace 1, respectively. A waste gas fan 12 and a fresh air fan 13 are installed on one side of the furnace 1. The waste gas fan 12 and the fresh air fan 13 are respectively connected to the waste gas passage 10 and the hot air passage 11. The outlet of the waste gas passage 10 is connected to the high-temperature waste gas passage 4. A natural gas burner 14 is also installed on the side of the high-temperature waste gas passage 4. When the temperature of the decomposition zone in the furnace does not reach the set value after the waste gas has undergone heat exchange, the natural gas burner 14 starts and stops automatically after the set temperature is reached. A hot air outlet pipe 15 is installed on the other side of the furnace 1. The outlet of the hot air passage 11 is connected to the hot air outlet pipe 15 to discharge the hot air.

[0017] A partition 16 is installed in the exhaust gas passage 10 and the hot air passage 11. A valve is machined on the partition 16. A valve plate 17 is provided on the surface of the valve. A shaft 18 is connected to the side of the valve plate 17. A pneumatic actuator 19 is provided above the furnace chamber 1. The pneumatic actuator 19 is connected to the shaft 18 on the side of the valve plate 17 to control the opening and closing of the valve plate.

[0018] In this embodiment, both the exhaust gas heat exchanger 5 and the hot air heat exchanger 6 are shell-and-tube heat exchangers. Both organic waste gas and fresh air flow inside the tubes. The exhaust gas passage 10 is equipped with a baffle to form two heating passes, A and B. After being preheated by the two heating passes, the exhaust gas enters the high-temperature exhaust gas passage 4. The hot air passage 11 is equipped with two baffles to form three heating passes, D, E, and F. After being heated by the three heating passes, the fresh air is discharged from the hot air outlet pipe 15, serving as the heat source for the drying oven.

[0019] A bracket 20 is installed above the furnace chamber 1. A pneumatic actuator 19 is connected to the bracket 20. The pneumatic actuator is a rotary cylinder. A drive shaft 21 is connected to the pneumatic actuator 19. The drive shaft 21 is connected to the bracket 20 through a bearing. Two upper and lower bearing supports 22 are connected to the partition plate 16. The shaft 18 is connected to the upper and lower bearing supports through a bearing. One end of the drive shaft 21 passes through the furnace chamber and is connected to the shaft 18 through a coupling 23. The air volume of the A and B return strokes and the D and E return strokes are controlled by opening and closing the control valve plate 17 to achieve temperature control.

[0020] An angle plate 24 is installed on the bracket 20, and a scale is provided on the angle plate 24. A pointer 25 is installed on the transmission shaft 21, and the pointer 25 points toward the scale on the angle plate 24 to display the opening and closing angle of the valve plate 17.

[0021] This utility model is not limited to the embodiments described. Those skilled in the art can still make some modifications or changes without departing from the spirit and scope of this utility model. Therefore, the scope of protection of this utility model shall be determined by the scope defined in the claims.

Claims

1. An automatic temperature control system for a combustion furnace, comprising a furnace chamber, one side of which is lined with a refractory brick wall, forming a high-temperature decomposition zone in the middle of the refractory brick wall; a waste gas heat exchanger and a hot air heat exchanger are sequentially installed on the other side of the furnace chamber; high-temperature flue gas from the decomposition zone is directed to the waste gas heat exchanger and the hot air heat exchanger; a flue gas duct is installed on the side of the hot air heat exchanger; and an exhaust fan is installed on the flue gas duct, characterized in that: The waste gas heat exchanger and the hot air heat exchanger form a waste gas passage and a hot air passage respectively between their sides and the side wall of the furnace. A waste gas fan and a fresh air fan are installed on one side of the furnace, which lead to the waste gas passage and the hot air passage respectively. A partition is installed in the waste gas passage and the hot air passage. A valve is machined on the partition. A valve plate is set on the surface of the valve. A shaft is connected to the side of the valve plate. A pneumatic actuator is set above the furnace. The pneumatic actuator is connected to the shaft on the side of the valve plate to control the opening and closing of the valve plate.

2. The automatic temperature control system for a combustion furnace according to claim 1, characterized in that: A baffle is provided at the junction of the waste gas heat exchanger and the hot air heat exchanger, connecting it to the side wall of the furnace.

3. The automatic temperature control system for a combustion furnace according to claim 1, characterized in that: A high-temperature exhaust gas passage is formed between the side of the refractory brick wall and the side of the furnace. A natural gas burner is installed on the side of the high-temperature exhaust gas passage, and the outlet of the exhaust gas passage is connected to the high-temperature exhaust gas passage.

4. The automatic temperature control system for a combustion furnace according to claim 1, characterized in that: A hot air outlet pipe is installed on the other side of the furnace, and the outlet of the hot air passage is connected to the hot air outlet pipe.

5. The automatic temperature control system for a combustion furnace according to claim 1, characterized in that: A bracket is installed above the furnace chamber, and a pneumatic actuator is connected to the bracket. A drive shaft is connected to the pneumatic actuator, and the drive shaft is connected to the bracket via bearings. Two upper and lower bearing brackets are connected to the partition plate, and the shaft is connected to the upper and lower bearing brackets via bearings. One end of the drive shaft passes through the furnace chamber and is connected to the shaft via a coupling.

6. An automatic temperature control system for a combustion furnace according to claim 1 or 5, characterized in that: The pneumatic actuator is a rotary cylinder.

7. The automatic temperature control system for a combustion furnace according to claim 5, characterized in that: An angle plate with graduations is mounted on the bracket, and a pointer is mounted on the drive shaft, with the pointer pointing toward the graduations on the angle plate.

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