Curing oven temperature regulation and control method and system based on waste heat recovery

Abstract

The invention provides a curing oven temperature regulation and control method and system based on waste heat recovery, and belongs to the field of waste heat recovery and reutilization. According to the curing oven temperature regulation and control method and system based on waste heat recovery, the set range where the temperature difference between the temperature of the waste heat pipeline and the temperature of the curing oven falls and the temperature difference between the actual temperature of the curing oven and the set value serve as the heat supply mode switching and temperature regulation and control triggering condition; the heat supply mode and the temperature regulation and control mode are automatically set according to different temperatures in a zoning mode. According to the curing oven temperature regulation and control method and system based on waste heat recovery, automatic switching of different heat supply modes can be achieved, the labor intensity of operators is reduced, meanwhile, the safety of the concentration of a combustible solvent in the curing oven and the stability of the pressure in the oven are guaranteed, and the curing oven temperature regulation and control method and system are suitable for industrial production. The risk that volatile gas overflows and explodes due to the fact that the concentration of the combustible solvent is too high and the pressure in the curing oven is unstable is prevented, and waste of resources is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste heat recovery and reuse, and specifically relates to a temperature control method and system of a curing furnace based on waste heat recovery. Background Art

[0002] A curing oven is a device used to solidify materials. Its main function is to control temperature, time and environmental conditions to induce chemical reactions in coatings, adhesives or other materials coated on the surface of objects, thereby achieving curing and enhancing the performance and stability of the materials.

[0003] When using a curing oven to dry and cure the paint on the strip, a volatile flammable solvent will be generated in the curing oven, so the inlet and outlet of the curing oven are required to maintain a slight negative pressure to prevent the volatile gas from leaking out, and at the same time, the curing oven must be supplemented with non-flammable gas fume or fresh air to ensure that the concentration of the flammable solvent in the curing oven is within the safe range of the lower explosion limit. Therefore, the curing oven not only needs to provide heat to meet the heat demand for the flammable solvent in the paint to fully volatilize, but also to ensure sufficient replacement of the gas in the curing oven to ensure safe production.

[0004] There are two existing temperature control debugging methods for curing furnaces:

[0005] One method is to use a burner to directly supply heat to the curing furnace, and the output power of the burner and the temperature of the curing furnace are controlled in a closed-loop linkage to achieve automatic temperature control of the curing furnace; however, this method can only supplement the heat in the curing furnace, while the gas in the curing furnace cannot be fully replaced, and the concentration of flammable solvents in the curing furnace will be higher.

[0006] Another method is to use the recovered waste heat to indirectly provide heat to the curing furnace. The recovered waste heat is input into the curing furnace as a heat transfer medium through high-temperature waste heat. The temperature of the curing furnace is controlled by a closed-loop linkage between the valve of the input medium and the temperature of the curing furnace to achieve automatic temperature control of the curing furnace. This method allows the gas in the curing furnace to be fully replaced, or even excessively replaced, but the temperature control effect is not good, and in order to reach the set temperature, the curing furnace often has a larger gas supply than exhaust, resulting in smoke at the curing furnace mouth, and even volatile gas leakage.

[0007] In the actual production operation process, in order to achieve a double balance between the heat and gas pressure and concentration in the curing furnace, the heating method of the curing furnace can use the above two heating methods at the same time, that is, the heating of the waste heat pipeline valve is set to manual control state, the heating method of the manually controlled waste heat pipeline valve is used as auxiliary heating, and the burner heating method is set to automatic to supplement the heat difference caused by the waste heat valve heating method.

[0008] However, in the actual production process, this control method may cause over-temperature or under-temperature, and even the waste heat pipeline may over-supply the heat transfer medium, resulting in unstable pressure in the curing furnace and excessive concentration of flammable solvents, which creates the risk of explosion of the curing furnace. At the same time, the combination of manually controlling the waste heat pipeline valve and the automatic heating of the burner cannot be used as a source of heat for the curing furnace when the waste heat pipeline temperature is low. The burner will heat the waste heat medium while heating the curing furnace, which will cause energy waste and the waste heat generated cannot be completely recovered.

[0009] Prior art CN212320445U discloses a heat recovery coke oven flue gas control system, wherein the carbonization chamber is provided with risers on the machine side and the coke side, respectively, and connected to the waste heat recovery boiler through a gas collecting pipe; a high-temperature gate valve, a riser temperature detection device, a riser pressure detection device and an oxygen content detection device are provided in the riser, a carbonization chamber temperature detection device and a carbonization chamber pressure detection device are provided in the carbonization chamber, and a combustion chamber temperature detection device and a combustion chamber pressure detection device are provided in the combustion chamber; the riser temperature detection device, the riser pressure detection device, the oxygen content detection device, the carbonization chamber temperature detection device, the carbonization chamber pressure detection device, the combustion chamber temperature detection device, the combustion chamber pressure detection device and the driving device of the high-temperature gate valve are respectively connected to the control system. This technology adjusts the opening of the high-temperature gate valve according to the detection values ​​of the temperature, pressure and oxygen content of each part in the coke oven, controls the flow of the high-temperature flue gas, and controls the negative pressure and temperature in each carbonization chamber. However, this technology does not consider the specific control method for automatic switching between self-heating of the burner and heating by waste heat. Summary of the invention

[0010] The present invention aims to address the problems of the prior art. The present invention provides a curing furnace temperature control method and system based on waste heat recovery, which can automatically set different temperature control modes and heating modes according to different temperature zones, reduce the labor intensity of operators, ensure the safety of the concentration of flammable solvents in the curing furnace, stabilize the pressure in the curing furnace, and have low energy consumption.

[0011] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0012] A curing furnace temperature control method based on waste heat recovery comprises the following steps:

[0013] S1. Divide the curing furnace into several areas;

[0014] S2. Detect the temperature of the waste heat pipeline and the temperature of the curing furnace in the middle area. When the temperature difference between the waste heat pipeline temperature and the temperature of the curing furnace in the middle area is less than or equal to a fixed value a, the waste heat pipeline valves in all areas are manually regulated, and the opening of the manual regulation of the waste heat pipeline valves is within a preset range (p, q], and the burners in all areas are set to automatically adjust the output power and regulate the flame state;

[0015] S3. Detect the temperature of the waste heat pipeline and the temperature of the curing furnace in the middle area. When the temperature difference between the waste heat pipeline temperature and the curing furnace in the middle area falls into the set range (a, b], where b>a, after the burner in the middle area is turned off, the waste heat pipeline valve in the middle area is allowed to switch to automatic temperature control, and the curing furnace in the middle area is heated by the waste heat pipeline. If it is less than the fixed value a, the burner in the middle area is re-ignited, and the waste heat pipeline valve in the middle area is changed to manual control;

[0016] S4. If the burner in the middle area is not turned off, continue to detect the temperature of the waste heat pipeline and the temperature of the curing furnace in the middle area. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area falls into the set range (b, c], where c>b, the burner in the middle area is forced to turn off, the waste heat pipeline valve in the middle area is forced to switch to automatic temperature control, and the curing furnace in the middle area is heated by the waste heat pipeline;

[0017] S5. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area falls within the set range (b, c], after the burner in the rear area is turned off, the waste heat pipeline valve in the rear area is allowed to switch to automatic temperature control, and the curing furnace in the rear area is heated by the waste heat pipeline. If the temperature difference is less than the fixed value b, the burner in the rear area is re-ignited, and the waste heat pipeline valve in the rear area is changed to manual control;

[0018] S6. If the burner in the rear area is not turned off, continue to detect the temperature of the waste heat pipeline and the temperature of the curing furnace in the middle area. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area falls into the set range (c, d], where d>c, the burner in the rear area is forced to turn off, the waste heat pipeline valve in the rear area is forced to switch to automatic temperature control, and the curing furnace in the rear area is heated by the waste heat pipeline;

[0019] S7. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area falls within the set range (c, d], after the burner in the previous area is turned off, the waste heat pipeline valve in the previous area is allowed to switch to automatic temperature control, and the curing furnace in the previous area is heated by the waste heat pipeline. If it is less than the fixed value c, the burner in the previous area is re-ignited, and the waste heat pipeline valve in the previous area is changed to manual control;

[0020] S8. If the burner in the previous area is not turned off, continue to detect the temperature of the waste heat pipeline and the temperature of the curing furnace in the middle area. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area is greater than the fixed value d, the burner in the previous area is forced to turn off, and the waste heat pipeline valve in the previous area is forced to switch to automatic temperature control. The curing furnace in the previous area is heated by the waste heat pipeline. At this time, the curing furnaces in the previous area, the middle area, and the rear area are all heated by the waste heat pipeline.

[0021] S9, the waste heat pipeline valves and burners of other areas after the latter area, and the waste heat pipeline valves and burners of other areas before the former area, all perform heating switching according to steps S2 to S8.

[0022] Preferably, in step S2, the preset range (p, q] of the opening of the waste heat pipeline valve manually adjusted is 5%-35%.

[0023] Preferably, in step S8, after the waste heat pipeline valves of the front area, the middle area, and the rear area are switched to automatic temperature control, if the temperature difference between the waste heat pipeline temperature and the curing furnace temperature of the middle area falls within the setting range of each step in steps S2 to S7, and does not meet the temperature difference condition of automatic temperature control, then the waste heat pipeline valves of the corresponding area determine whether to switch to manual control according to the setting range within which the temperature difference falls.

[0024] Preferably, if the waste heat pipeline valve in a certain area is switched to manual control, the burner in this area is reignited, and the temperature of the waste heat pipeline and the curing furnace in the middle area is continued to be detected, and based on the temperature difference range between the waste heat pipeline and the curing furnace in the middle area, it is determined whether the waste heat pipeline valve in this area is switched to automatic temperature control.

[0025] Preferably, if the waste heat pipeline valve in a certain area is switched to manual control, after the burner in this area is reignited, it is detected that the actual temperature of the curing furnace in this area is greater than the set value M, and the temperature difference is greater than the fixed value m, then the burner in this area is extinguished again and the preset range of the opening of the manual control of the waste heat pipeline valve is (p, q'), where q'<q.

[0026] Preferably, if the waste heat pipeline valve in a certain area is switched to automatic temperature control, after the burner in this area is turned off, it is detected that the actual temperature of the curing furnace in this area is less than the set value M, and the temperature difference is greater than the fixed value m, then the waste heat pipeline valve in this area is switched to manual control, the opening of the manual control is q, and the burner in this area is reignited.

[0027] The present invention also provides a curing furnace temperature control system based on waste heat recovery, which controls the temperature of the curing furnace according to the curing furnace temperature control method as described above, and includes a plurality of curing furnace areas, a plurality of burners, a plurality of waste heat pipeline valves, and a waste heat pipeline;

[0028] The number of curing furnace areas is equal to the number of burners and waste heat pipeline valves;

[0029] Some of the curing ovens are used to dry and cure the materials;

[0030] Several of the burners are used to provide heat for the curing furnace;

[0031] The waste heat pipeline is used to recover waste heat and input the waste heat into the curing furnace through a heat transfer medium;

[0032] The plurality of waste heat pipeline valves are arranged between the waste heat pipeline and the plurality of curing furnaces, and control the flow of the heat transfer medium;

[0033] Some of the curing furnace areas are also provided with a curing furnace temperature detection device for detecting the temperature of some of the curing furnace areas;

[0034] A waste heat temperature detection device is also provided between the waste heat pipeline and a plurality of waste heat pipeline valves, for detecting the temperature of the waste heat of the plurality of waste heat pipelines.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] (1) The present invention provides a curing furnace temperature control method and system based on waste heat recovery, which can realize automatic switching and temperature control between burner heating and waste heat heating, and ensure that the concentration of the flammable solvent in the curing furnace is kept within a safe range and the pressure in the curing furnace is stable, thereby preventing the risk of volatile gas overflow and explosion caused by excessive concentration of the flammable solvent and unstable pressure in the curing furnace, and avoiding waste of resources;

[0037] (2) The present invention provides a method and system for controlling the temperature of a curing furnace based on waste heat recovery. By using the temperature difference between the waste heat pipeline temperature and the curing furnace, and the temperature difference between the actual temperature of the curing furnace and the set value, as the trigger conditions for switching between burner heating and waste heat heating and temperature control, the heating mode and temperature control mode are automatically set according to different temperature zones. The operator does not need to manually monitor and adjust different heating modes in real time, which reduces the operator's labor intensity and reduces energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a partial schematic diagram of a curing furnace temperature control system based on waste heat recovery according to an embodiment of the present invention;

[0039] Figure 2 It is an overall schematic diagram of a curing furnace temperature control system based on waste heat recovery according to an embodiment of the present invention.

[0040] The specific meanings of the symbols in the accompanying drawings are as follows:

[0041] 1. Curing furnace area; 11. Curing furnace temperature detection device; 2. Burner; 3. Waste heat pipeline valve; 4. Waste heat pipeline; 41. Waste heat temperature detection device. DETAILED DESCRIPTION

[0042] The following is a clear and complete description of a curing furnace temperature control method and system based on waste heat recovery of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Example 1

[0044] According to a specific embodiment of the present invention, a method for controlling the temperature of a curing furnace based on waste heat recovery of the present invention is described in detail below.

[0045] The present invention provides a curing furnace temperature control method based on waste heat recovery, comprising the following steps:

[0046] S1. Divide the curing furnace into several areas;

[0047] S2. Detect the temperature of the curing furnace in the waste heat pipeline and the middle area. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area is less than a fixed value a, in this embodiment, the fixed value a is 100° C., the preheating pipeline valves in all areas are switched from program control to manual control or automatic control, the program of the waste heat pipeline valves in all areas is switched to manual control, and the opening of the manual control of the waste heat pipeline valve is a preset range (p, q], specifically, the preset range (p, q] is 5%-35%, and the burners in all areas are set to automatically adjust the output power, that is, the existing burner output power and the temperature of the curing furnace are used for closed-loop interlocking control to automatically adjust the flame state;

[0048] At this stage, the waste heat pipeline valves in all areas are manually controlled, and they cannot be switched to automatic temperature control even if they are manually operated. This is because the temperature of the heat transfer medium of the waste heat is relatively low at this time. The preset range of the opening of the manual control of the waste heat pipeline valve is set to 5%-35%. The heat transfer medium is transported mainly to replace the air in the curing furnace, so that the concentration of the flammable solvent in the curing furnace is kept within a safe range; and the manual control of the opening of the waste heat pipeline valve is controlled below 35%, which can prevent the burner from heating the heat transfer medium when heating the curing furnace, thereby preventing waste of resources, and also preventing the pressure in the curing furnace from increasing due to excessive heating and expansion of the heat transfer medium, preventing smoke from the curing furnace mouth, and even causing volatile gas leakage.

[0049] S3, detecting the temperature of the waste heat pipeline and the curing furnace in the middle area. When the temperature difference between the waste heat pipeline temperature and the curing furnace in the middle area falls into the set range (a, b], where b>a, specifically, the set range (a, b] is 100°C-180°C, after the burner in the middle area is turned off; the waste heat pipeline valve in the middle area is allowed to switch to automatic temperature control, and the curing furnace in the middle area is heated by the waste heat pipeline. If it is less than the fixed value a, the burner in the middle area is re-ignited, and the waste heat pipeline valve in the middle area is changed to manual control;

[0050] During this stage, the waste heat pipeline valve in the middle area needs to judge whether to switch to automatic temperature control based on the temperature difference. However, whether the waste heat pipeline valve in the middle area is manually controlled or automatically controlled, the heat transfer medium it transports can meet the demand for replacing the air in the curing furnace in the middle area.

[0051] S4. If the burner in the middle area is not turned off, continue to detect the temperature of the waste heat pipeline and the temperature of the curing furnace in the middle area. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area falls within the set range (b, c], specifically, the set range (b, c] is 180°C-230°C, the waste heat pipeline valve in the middle area is forced to switch to automatic temperature control, and the curing furnace in the middle area is heated by the waste heat pipeline;

[0052] S5. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area falls within the set range (b, c], after the burner in the rear area is turned off, the waste heat pipeline valve in the rear area is allowed to switch to automatic temperature control, and the curing furnace in the rear area is heated by the waste heat pipeline. If the temperature difference is less than the fixed value b, the burner in the rear area is re-ignited, and the waste heat pipeline valve in the rear area is changed to manual control;

[0053] At this stage, the waste heat pipeline valves in the middle area are forced to switch to automatic temperature control. The heat transfer medium transported by the waste heat pipeline valves in the middle area can simultaneously meet the air replacement and heating needs of the curing furnace in the middle area. There is no need for the burner in the middle area to supply heat, and the burner in the middle area is forced to shut down. The waste heat pipeline valves in the rear area need to determine whether to switch to automatic temperature control based on the temperature difference. However, no matter whether the waste heat pipeline valves in the rear area are manually adjusted or automatically controlled, the heat transfer medium they transport can meet the need to replace the air in the curing furnace in the rear area.

[0054] S6. If the burner in the rear area is not turned off, continue to detect the temperature of the waste heat pipeline and the temperature of the curing furnace in the middle area. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area falls into the set range (c, d], where d>c, specifically, the set range (c, d] is 230°C-260°C, the burner in the rear area is forced to turn off, the waste heat pipeline valve in the rear area is forced to switch to automatic temperature control, and the curing furnace in the rear area is heated by the waste heat pipeline;

[0055] S7. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area falls within the set range (c, d], after the burner in the previous area is turned off, the waste heat pipeline valve in the previous area is allowed to switch to automatic temperature control, and the curing furnace in the previous area is heated by the waste heat pipeline. If it is less than the fixed value c, the burner in the previous area is re-ignited, and the waste heat pipeline valve in the previous area is changed to manual control;

[0056] During this stage, the waste heat pipeline valves in the middle area and the rear area are forced to switch to automatic temperature control. The heat transfer medium transported by the waste heat pipeline valves in the middle area and the rear area can simultaneously meet the air replacement and heating needs of the curing furnace in the middle area and the rear area. There is no need for the burners in the middle area and the rear area to heat, and the burners in the middle area and the rear area are forced to shut down; the waste heat pipeline valves in the front area need to judge whether to switch to automatic temperature control based on the temperature difference, but no matter the waste heat pipeline valves in the front area are manually adjusted or automatically controlled, the heat transfer medium they transport can meet the need to replace the air in the curing furnace in the front area.

[0057] S8. If the burner in the previous area is not turned off, continue to detect the temperature of the waste heat pipeline and the curing furnace in the middle area. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area is greater than the fixed value d, the burner in the previous area is forced to turn off, and the waste heat pipeline valve in the previous area is forced to switch to automatic temperature control. The curing furnace in the previous area is heated by the waste heat pipeline. At this time, the curing furnaces in the previous area, the middle area, and the back area are all heated by the waste heat pipeline.

[0058] At this stage, the waste heat pipeline valves in the front area, middle area and rear area are forced to switch to automatic temperature control, and the heat transfer medium transported by the waste heat pipeline valves in the front area, middle area and rear area can simultaneously meet the air replacement and heating needs of the curing furnaces in the front area, middle area and rear area. There is no need for the burners in the front area, middle area and rear area to supply heat, and the burners in the front area, middle area and rear area are forced to shut down. In this state, the heating method of the curing furnace in each area adopts waste heat pipeline heating.

[0059] S9, the waste heat pipeline valves and burners of other areas after the latter area, and the waste heat pipeline valves and burners of other areas before the former area, all perform heating switching according to steps S2 to S8.

[0060] Example 2

[0061] Different from Example 1, in this embodiment, in step S8, after the waste heat pipeline valves of the previous area, the middle area, and the rear area are switched to automatic temperature control, if the temperature difference between the waste heat pipeline temperature and the curing furnace temperature of the middle area falls within the setting range of each step in step S2 to step S7, and does not meet the temperature difference condition of automatic temperature control, then the waste heat pipeline valve of the corresponding area determines whether to switch to manual control according to the setting range within which the temperature difference falls; if the waste heat pipeline valve of the corresponding area is switched to manual control, the burner in the area is allowed to re-ignite, and the temperature of the waste heat pipeline and the curing furnace in the middle area continues to be detected, and according to the temperature difference range between the waste heat pipeline and the curing furnace in the middle area, it is determined whether the waste heat pipeline valve in the area is switched to automatic temperature control.

[0062] Example 3

[0063] In this embodiment, if the waste heat pipeline valve in a certain area is switched to manual control, after the burner in this area is reignited, it is detected that the actual temperature of the curing furnace in this area is greater than the set value M, and the temperature difference is greater than the fixed value m, specifically, the fixed value m is 3°C, then the burner in this area is extinguished again and the preset range of the opening of the manual control of the waste heat pipeline valve is (p, q'), where q'<q.

[0064] In order to meet the demand for material drying and curing, the temperature of the curing furnace is set to M. When the waste heat pipeline valve is manually controlled, if the actual temperature of the curing furnace exceeds the set value M and exceeds 3°C, it means that the opening of the manual control of the waste heat pipeline valve is too large. Therefore, it is necessary to reduce the preset opening range of the manual control of the waste heat pipeline valve to reduce the actual temperature of the curing furnace.

[0065] Example 4

[0066] If the waste heat pipeline valve in a certain area is switched to automatic temperature control, after the burner in this area is turned off, it is detected that the actual temperature of the curing furnace in this area is less than the set value M, and the temperature difference is greater than the fixed value m, specifically, the fixed value m is 3°C, then the waste heat pipeline valve in this area is switched to manual control, the opening of the manual control is q, and the burner in this area is reignited.

[0067] When the waste heat pipeline valve in a certain area is switched to automatic temperature control, the curing furnace in this area is heated by the waste heat pipeline. At this time, the temperature difference between the waste heat pipeline temperature and the curing furnace temperature is greater than the fixed value a, but the actual temperature of the curing furnace is lower than the set value M, and is more than 3°C lower, which means that the waste heat pipeline cannot meet the heating demand of the curing furnace. At this time, the waste heat pipeline valve is switched from the automatic temperature control state to the manual control state, and the manual control opening is set to the maximum value q, and the burner is re-ignited to increase the actual temperature of the curing furnace.

[0068] Example 5

[0069] According to a specific embodiment of the present invention, a curing furnace temperature control system based on waste heat recovery of the present invention is described in detail below.

[0070] like Figure 1-2 As shown, the present invention also provides a curing furnace temperature control system based on waste heat recovery, which controls the temperature of the curing furnace according to the curing furnace temperature control method as described above, including several curing furnace areas 1, several burners 2, several waste heat pipeline valves 3, and a waste heat pipeline 4; the number of the curing furnace areas is equal to the number of burners and waste heat pipeline valves; several of the curing furnaces are used to dry and cure materials; several of the burners are used to provide heat for the curing furnaces; the waste heat pipeline is used to recover waste heat and input the waste heat into the curing furnace through a heat transfer medium; several of the waste heat pipeline valves are arranged between the waste heat pipeline and the several curing furnaces, and control the flow rate of the heat transfer medium; several of the curing furnace areas are also provided with a curing furnace temperature detection device 11 for detecting the temperature of several of the curing furnace areas; a waste heat temperature detection device 41 is also provided between the waste heat pipeline and several of the waste heat pipeline valves for detecting the temperature of the waste heat of several of the waste heat pipelines.

[0071] In this embodiment, zone one, zone two, and zone three are represented as the previous area, the middle area, and the next area. When there are multiple areas, the temperature control method described above is still used for control. For example, when there are five areas, the third area is the middle area, the fourth area is the next area, the second area is the previous area, and so on. The fifth area is the next area when the next round of temperature control is performed according to the method described above, and the first area is the previous area when the next round of temperature control is performed according to the method described above. The overall temperature control method of the system is performed according to the steps described above.

[0072] The above description is only an embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the application scope of the present invention shall be included in the protection scope of the present invention.

Claims

1. A curing furnace temperature control method based on waste heat recovery, characterized in that: The following steps are involved: S1. Divide the curing furnace into several areas; S2. Detect the temperature of the waste heat pipeline and the temperature of the curing furnace in the middle area. When the temperature difference between the waste heat pipeline temperature and the temperature of the curing furnace in the middle area is less than or equal to a fixed value a, the waste heat pipeline valves in all areas are manually regulated, and the opening of the manual regulation of the waste heat pipeline valves is within a preset range (p, q], and the burners in all areas are set to automatically adjust the output power and regulate the flame state; S3, detecting the temperature of the waste heat pipeline and the temperature of the curing furnace in the middle area. When the temperature difference between the waste heat pipeline temperature and the curing furnace in the middle area falls into the set range (a, b], where b>a, after the burner in the middle area is turned off, the waste heat pipeline valve in the middle area is switched to automatic temperature control, and the curing furnace in the middle area is heated by the waste heat pipeline. If it is less than the fixed value a, the burner in the middle area is re-ignited, and the waste heat pipeline valve in the middle area is changed to manual control; S4. If the burner in the middle area is not turned off, continue to detect the temperature of the waste heat pipeline and the temperature of the curing furnace in the middle area. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area falls into the set range (b, c], where c>b, the burner in the middle area is forced to turn off, the waste heat pipeline valve in the middle area is forced to switch to automatic temperature control, and the curing furnace in the middle area is heated by the waste heat pipeline; S5. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area falls within the set range (b, c], after the burner in the rear area is turned off, the waste heat pipeline valve in the rear area is switched to automatic temperature control, and the curing furnace in the rear area is heated by the waste heat pipeline. If the temperature difference is less than the fixed value b, the burner in the rear area is re-ignited, and the waste heat pipeline valve in the rear area is changed to manual control; S6. If the burner in the rear area is not turned off, continue to detect the temperature of the waste heat pipeline and the temperature of the curing furnace in the middle area. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area falls into the set range (c, d], where d>c, the burner in the rear area is forced to turn off, the waste heat pipeline valve in the rear area is forced to switch to automatic temperature control, and the curing furnace in the rear area is heated by the waste heat pipeline; S7. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area falls within the set range (c, d], after the burner in the previous area is turned off, the waste heat pipeline valve in the previous area is switched to automatic temperature control, and the curing furnace in the previous area is heated by the waste heat pipeline. If it is less than the fixed value c, the burner in the previous area is re-ignited, and the waste heat pipeline valve in the previous area is changed to manual control; S8. If the burner in the previous area is not turned off, continue to detect the temperature of the waste heat pipeline and the temperature of the curing furnace in the middle area. When the temperature difference between the waste heat pipeline and the curing furnace in the middle area is greater than the fixed value d, the burner in the previous area is forced to turn off, and the waste heat pipeline valve in the previous area is forced to switch to automatic temperature control. The curing furnace in the previous area is heated by the waste heat pipeline. At this time, the curing furnaces in the previous area, the middle area, and the rear area are all heated by the waste heat pipeline. S9, the waste heat pipeline valves and burners of other areas after the latter area, and the waste heat pipeline valves and burners of other areas before the former area, all perform heating switching according to steps S2 to S8.

2. The method for controlling the temperature of a curing furnace based on waste heat recovery according to claim 1, characterized in that: In step S2, the preset range (p, q] of the opening of the waste heat pipeline valve manually adjusted is 5%-35%.

3. The curing furnace temperature control method based on waste heat recovery according to claim 1 is characterized in that: In step S8, after the waste heat pipeline valves of the front area, the middle area, and the rear area are switched to automatic temperature control, if the temperature difference between the waste heat pipeline temperature and the curing furnace temperature of the middle area falls within the setting range of each step from step S2 to step S7, and does not meet the temperature difference condition of automatic temperature control, the waste heat pipeline valves of the corresponding area determine whether to switch to manual control according to the setting range within which the temperature difference falls.

4. The curing furnace temperature control method based on waste heat recovery according to claim 3 is characterized in that: If the waste heat pipeline valve in a certain area is switched to manual control, the burner in this area is ignited again, and the temperature of the waste heat pipeline and the curing furnace in the middle area is continued to be detected. Based on the temperature difference range of the waste heat pipeline and the curing furnace in the middle area, it is determined whether the waste heat pipeline valve in this area is switched to automatic temperature control.

5. The method for controlling the temperature of a curing furnace based on waste heat recovery according to claim 4, characterized in that: If the waste heat pipeline valve of a certain area is switched to manual control, after the burner in this area is reignited, it is detected that the actual temperature of the curing furnace in this area is greater than the set value M, and the temperature difference is greater than the fixed value m, then the burner in this area is extinguished again and the preset range of the opening of the manual control of the waste heat pipeline valve is (p, q'), where q'<q.

6. The method for controlling the temperature of a curing furnace based on waste heat recovery according to claim 5, characterized in that: If the waste heat pipeline valve in a certain area is switched to automatic temperature control, after the burner in this area is turned off, it is detected that the actual temperature of the curing furnace in this area is less than the set value M, and the temperature difference is greater than the fixed value m, then the waste heat pipeline valve in this area is switched to manual control, the opening of the manual control is q, and the burner in this area is reignited.

7. A curing furnace temperature control system based on waste heat recovery, characterized in that: The curing furnace temperature control method according to any one of claims 1 to 6 is used to control the curing furnace temperature, comprising a plurality of curing furnace areas, a plurality of burners, a plurality of waste heat pipeline valves, and a waste heat pipeline; The number of curing furnace areas is equal to the number of burners and waste heat pipeline valves; Some of the curing ovens are used to dry and cure the materials; Several of the burners are used to provide heat for the curing furnace; The waste heat pipeline is used to recover waste heat and input the waste heat into the curing furnace through a heat transfer medium; The plurality of waste heat pipeline valves are arranged between the waste heat pipeline and the plurality of curing furnaces, and control the flow of the heat transfer medium; Some of the curing furnace areas are also provided with a curing furnace temperature detection device for detecting the temperature of some of the curing furnace areas; A waste heat temperature detection device is also provided between the waste heat pipeline and a plurality of waste heat pipeline valves, for detecting the temperature of the waste heat of the plurality of waste heat pipelines.

Images