A high-temperature hot air blower set for drying desulfurized gypsum board and a control method thereof

Abstract

This invention relates to the field of high-temperature hot air drying energy-saving technology, specifically to a high-temperature hot air unit and its control method for drying desulfurized gypsum board. The high-temperature hot air unit for drying desulfurized gypsum board includes a fresh air total heat exchanger, a multi-stage heat exchange module, an air valve switching module, a first fan, and a second fan. It also includes a gas detection sensor, an alkaline sprayer, and a vortex air chamber. The multi-stage heat exchange module includes a high-temperature fixed-frequency compressor submodule, a low-temperature variable-frequency compressor submodule, and a low-temperature fixed-frequency compressor submodule. This high-temperature hot air unit and its control method for drying desulfurized gypsum board address the core deficiencies of existing technologies in the field of desulfurized gypsum board drying by achieving significant technological breakthroughs and enhanced application value through the coordinated design of the fresh air total heat exchanger, the multi-stage heat exchange module, the vortex air chamber, and the gas detection sensor.

Description

Technical Field

[0001] This invention relates to the field of high-temperature hot air drying energy-saving technology, specifically to a high-temperature hot air unit for drying desulfurized gypsum board and its control method. Background Technology

[0002] With the continuous tightening of environmental regulations in the building materials industry, desulfurized gypsum board, as a representative product of industrial solid waste resource utilization, has increasingly higher requirements for temperature control precision, environmental compliance and energy efficiency in its drying process. Low-energy-consumption drying equipment with corrosion resistance has become a core demand of the industry.

[0003] Currently, desulfurized gypsum board drying operations mainly rely on two types of technical solutions. One type is high-temperature heat pump drying equipment, which uses segmented heating in medium and high temperature sections to construct a circulating heating process. This, combined with a fan and heating chamber, forms a drying airflow circulation system, primarily suitable for drying materials in scenarios with medium-to-low grade heat sources. The other type is a dedicated desulfurized gypsum drying device, which uses a heating shaft and spiral stirring blades working in tandem. Heating wires heat the airflow before it is guided into the drying tank to complete the drying process.

[0004] Existing technologies have several significant shortcomings. The highest outlet air temperature of high-temperature heat pump drying equipment can only reach 120℃, which is insufficient to meet the 160℃ temperature standard required for drying desulfurized gypsum board, necessitating the addition of an auxiliary gas heating device. The exhaust gas generated during the drying process contains nitrogen oxides and sulfides. These substances, when combined with condensate, produce acidic fluids such as nitric acid and sulfuric acid. Existing waste heat recovery heat exchangers lack a specialized corrosion-resistant design, making them susceptible to damage from acidic condensate. Furthermore, existing equipment operates in an open manner, directly discharging the high-temperature exhaust gas generated during drying without effective waste heat recovery, resulting in low energy efficiency. In addition, all existing drying units lack a dynamic adjustment mechanism based on the gas concentration inside the drying chamber, preventing adjustments to equipment operating parameters according to the material drying process.

[0005] Therefore, there is an urgent need for better technical solutions to overcome the above limitations. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this application provides a high-temperature hot air unit and its control method for drying desulfurized gypsum board. This high-temperature hot air unit and its control method for drying desulfurized gypsum board address the core deficiencies of existing technologies in the field of desulfurized gypsum board drying. Through the coordinated design of a fresh air total heat exchanger, multi-stage heat exchange modules, a vortex air chamber, and gas detection sensors, it achieves significant technological breakthroughs and enhances application value.

[0007] To achieve the above objectives, the present invention provides a high-temperature hot air unit for drying desulfurized gypsum board.

[0008] The high-temperature hot air unit for drying desulfurized gypsum board includes a fresh air total heat exchanger, a multi-stage heat exchange module, an air valve switching module, a first fan, and a second fan.

[0009] The multi-stage heat exchange module includes a high-temperature fixed-frequency compressor submodule, a low-temperature variable-frequency compressor submodule, and a low-temperature fixed-frequency compressor submodule. The high-temperature fixed-frequency compressor submodule includes a high-temperature fixed-frequency compressor, a condenser, an electronic expansion valve, and an evaporator connected in series to form a circulation loop. The low-temperature variable-frequency compressor submodule includes a low-temperature variable-frequency compressor, a condenser, an electronic expansion valve, and an evaporator connected in series to form a circulation loop. The low-temperature fixed-frequency compressor submodule also includes a low-temperature fixed-frequency compressor, a condenser, an electronic expansion valve, and an evaporator connected in series to form a circulation loop. The condensers of the high-temperature fixed-frequency compressor submodule, the low-temperature variable-frequency compressor submodule, and the low-temperature fixed-frequency compressor submodule are connected in series via condensing pipes, and the evaporators of the same submodule are connected in series via evaporating pipes. The condensing pipes and the evaporating pipes are connected via switching pipes.

[0010] The air inlet of the first fan is connected to the condenser duct, and the air outlet of the second fan is connected to the evaporator duct. The fresh air total heat exchanger is connected to both the condenser duct and the evaporator duct.

[0011] The air valve switching module includes a first air valve, a second air valve, and a third air valve, which are respectively installed on the condensation pipe, the evaporation pipe, and the switching pipe.

[0012] Preferably, the evaporation pipe is further provided with a gas detection sensor, an alkaline sprayer, and a vortex air chamber. The gas detection sensor is located at the air outlet of the evaporation pipe near the second fan and is connected to the alkaline sprayer. The alkaline sprayer is located on the upwind side of the vortex air chamber.

[0013] Preferably, the multi-stage heat exchange module includes at least two high-temperature fixed-frequency compressor sub-modules and at least two low-temperature fixed-frequency compressor sub-modules.

[0014] The present invention also provides a control method for a high-temperature hot air unit for drying desulfurized gypsum board, applicable to any of the above-mentioned high-temperature hot air units for drying desulfurized gypsum board.

[0015] The control method includes the following steps: When starting the high-temperature hot air unit, turn on the first and second fans, start the low-temperature variable frequency compressor submodule and the low-temperature fixed frequency compressor submodule, open the second air valve, and close the first and third air valves.

[0016] When the temperature of the drying chamber reaches the start-up setting value of the high-temperature fixed-frequency press submodule, the high-temperature fixed-frequency press submodule is started.

[0017] After the high-temperature hot air unit is running stably, the operating mode of the high-temperature hot air unit can be switched by adjusting the first air valve, the second air valve and the third air valve. The operating modes of the high-temperature hot air unit include closed circulation mode or fresh air mode.

[0018] When switching to closed-loop mode, open the second air valve and close the first and third air valves.

[0019] When switching to fresh air mode, close the second air valve and open the first and third air valves.

[0020] Preferably, the start-up setting value for the high-temperature fixed-frequency compressor submodule is 50~60℃.

[0021] Preferably, the control method further includes the following steps: acquiring the acid gas concentration value detected by the gas detection sensor; starting the alkaline sprayer when the detected acid gas concentration value exceeds the concentration set value; and turning off the alkaline sprayer when the detected acid gas concentration value is less than or equal to the concentration set value.

[0022] Preferably, the acid gas concentration is set to 200ppm to 500ppm.

[0023] Preferably, when the alkali sprayer is started, the high-temperature hot air unit switches to fresh air mode, and when the alkali sprayer is turned off, the high-temperature hot air unit switches to closed-loop mode.

[0024] Preferably, the pH value of the condensate is obtained. When the pH value of the condensate is less than the lower limit of the set range, the alkaline spray volume of the alkaline sprayer is increased. When the pH value of the condensate is greater than the upper limit of the set range, the alkaline spray volume of the alkaline sprayer is decreased.

[0025] Preferably, the pH value of the condensate is set in the range of 6.5 to 7.5.

[0026] Compared with the prior art, the beneficial effects of this application are as follows: Firstly, the high-temperature hot air unit and its control method for drying desulfurized gypsum board solve the problem of insufficient outlet air temperature in existing equipment, which requires gas-fired assistance. Relying on multi-stage heat exchange module linkage, the unit's maximum supply air temperature can reach 165℃, directly meeting the 160℃ temperature requirement for drying desulfurized gypsum board. This eliminates the need for an additional gas-fired boiler, avoiding the increased nitrogen oxide emissions from gas heating and reducing the energy cost per ton of desulfurized gypsum board dried, thus meeting the dual environmental and energy-saving requirements of the building materials industry.

[0027] Secondly, it effectively solves the problems of acidic condensate corrosion and exhaust gas pollution. Through a vortex air chamber connecting the drying chamber and multi-stage heat exchange modules, combined with gas detection sensors and alkaline sprayers installed in the pipelines, it ensures that the condensate pH remains stable within the neutral range of 6.5-7.5, preventing acidic liquid corrosion of the condenser and evaporator. This extends the heat exchanger maintenance cycle to 2-3 times that of traditional equipment, while simultaneously eliminating the environmental pollution caused by nitrogen oxides and sulfides.

[0028] Furthermore, it significantly improves the system's energy efficiency and adaptability to different operating conditions. The air valve switching module enables automatic switching between closed-loop circulation and fresh air modes, ensuring that the gas concentration in the drying chamber meets standards while minimizing heat loss. In addition, the multi-stage heat exchange module can adapt to the temperature requirements of different drying stages of desulfurized gypsum board and also provides adaptability for other industrial materials requiring high-temperature drying. Attached Figure Description

[0029] This application can be better understood by describing its embodiments in conjunction with the accompanying drawings, in which: Figure 1 This is a schematic diagram of the structure of a high-temperature hot air unit for drying desulfurized gypsum board in an embodiment of this application.

[0030] Explanation of icon numbers: 1. Fresh air heat exchanger; 2. First fan; 3. Second fan; 4. High-temperature fixed-frequency compressor; 5. Condenser; 6. Electronic expansion valve; 7. Evaporator; 8. Low-temperature variable-frequency compressor; 9. Condenser; 10. Electronic expansion valve; 11. Evaporator; 12. Low-temperature fixed-frequency compressor; 13. Condenser; 14. Electronic expansion valve; 15. Evaporator; 16. Condensation pipe; 17. Evaporation pipe; 18. Switching pipe; 19. First air valve; 20. Second air valve; 21. Third air valve; 22. Gas detection sensor; 23. Alkali sprayer; 24. Vortex air chamber. Detailed Implementation

[0031] Unless otherwise defined, the technical or scientific terms used in this specification and claims shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0032] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Embodiments of the present invention include, for example Figure 1 The high-temperature hot air unit shown is used for drying desulfurized gypsum board.

[0037] The high-temperature hot air unit for drying desulfurized gypsum board includes a fresh air total heat exchanger 1, a multi-stage heat exchange module, an air valve switching module, a first fan 2, and a second fan 3.

[0038] The multi-stage heat exchange module includes a high-temperature fixed-frequency compressor submodule, a low-temperature variable-frequency compressor submodule, and a low-temperature fixed-frequency compressor submodule. The high-temperature fixed-frequency compressor submodule includes a high-temperature fixed-frequency compressor 4, a condenser 5, an electronic expansion valve 6, and an evaporator 7 connected in series to form a circulation loop. The low-temperature variable-frequency compressor submodule includes a low-temperature variable-frequency compressor 8, a condenser 9, an electronic expansion valve 10, and an evaporator 11 connected in series to form a circulation loop. The low-temperature fixed-frequency compressor submodule includes a low-temperature fixed-frequency compressor 12, a condenser 13, an electronic expansion valve 14, and an evaporator 15 connected in series to form a circulation loop. The condensers 5, 9, and 13 of the high-temperature fixed-frequency compressor submodule, the low-temperature variable-frequency compressor submodule, and the low-temperature fixed-frequency compressor submodule are connected in series via condensing pipes 16. The evaporators 7, 11, and 15 of the high-temperature fixed-frequency compressor submodule, the low-temperature variable-frequency compressor submodule, and the low-temperature fixed-frequency compressor submodule are connected in series via evaporating pipes 17. The condensing pipe 16 and the evaporating pipe 17 are connected via a switching pipe 18.

[0039] Preferably, the multi-stage heat exchange module includes at least two high-temperature fixed-frequency compressor sub-modules and at least two low-temperature fixed-frequency compressor sub-modules. In the embodiment shown in the figure, the multi-stage heat exchange module includes four high-temperature fixed-frequency compressor sub-modules, two low-temperature variable-frequency compressor sub-modules, and one low-temperature fixed-frequency compressor sub-module. These seven sub-modules are connected in series to form an eight-stage heat exchange process, enabling deep cooling and dehumidification of the airflow and stepped heating, ensuring that the unit's maximum supply air temperature reaches 165°C, meeting the 160°C temperature requirement for drying desulfurized gypsum board. This eliminates the need for an additional gas-fired boiler, avoiding the increased nitrogen oxide emissions associated with traditional gas-fired auxiliary heating.

[0040] The air inlet of the first fan 2 is connected to the condenser pipe 16, and the air outlet of the second fan 3 is connected to the evaporator pipe 17. The fresh air total heat exchanger 1 is connected to both the condenser pipe 16 and the evaporator pipe 17.

[0041] The air valve switching module includes a first air valve 19, a second air valve 20, and a third air valve 21, which are respectively installed on the condensation pipe 16, the evaporation pipe 17, and the switching pipe 18.

[0042] Preferably, the evaporation pipe 17 is further equipped with a gas detection sensor 22, an alkaline sprayer 23, and a vortex chamber 24. The gas detection sensor 22 is located near the air outlet of the second fan 3 on the evaporation pipe 17 and is connected to the alkaline sprayer 23, which is located on the upwind side of the vortex chamber 24. The gas detection sensor 22 can be used to collect the concentration of acidic gases such as nitrogen oxides and sulfides in the airflow in real time. When the concentration exceeds the standard, the alkaline sprayer 23 is activated to spray alkaline solution into the vortex chamber 24. The vortex chamber 24 can make the airflow form a spiral flow field, prolonging the contact time between the airflow and the alkaline solution, ensuring complete neutralization of acidic gases, and preventing them from combining with condensate to form nitric acid and sulfuric acid that corrode the condenser and evaporator, thus extending the heat exchanger maintenance cycle to 2 to 3 times that of traditional equipment.

[0043] The present invention also provides a control method for a high-temperature hot air unit for drying desulfurized gypsum board, applicable to any of the above-mentioned high-temperature hot air units for drying desulfurized gypsum board.

[0044] The control method includes the following steps: When starting the high-temperature hot air unit, turn on the first fan 2 and the second fan 3, start the low-temperature variable frequency compressor submodule and the low-temperature fixed frequency compressor submodule, open the second air valve 20, and close the first air valve 19 and the third air valve 21. In some specific embodiments, when starting the low-temperature compressor submodule, first start the low-temperature fixed frequency compressor submodule, run it for 5-8 minutes until the system pressure and temperature stabilize, and then start the low-temperature variable frequency compressor submodule. This can avoid the problem of excessive starting load caused by starting multiple low-temperature compressors at the same time, and ensure the stable operation of the unit.

[0045] When the temperature of the drying chamber reaches the start-up setting value of the high-temperature fixed-frequency compressor submodule, the high-temperature fixed-frequency compressor submodule is activated. The start-up setting value of the high-temperature fixed-frequency compressor submodule can be 50~60℃. Specifically, after activating the high-temperature fixed-frequency compressor submodule, the heating power can be coarsely adjusted by increasing or decreasing the number of high-temperature fixed-frequency compressor submodules activated according to the target temperature requirement of the drying chamber. Then, fine adjustment is made by adjusting the operating frequency of the low-temperature variable-frequency compressor submodule to stabilize the outlet air temperature within the set value ±2℃ range, adapting to the temperature requirements of the desulfurized gypsum board throughout the entire process from preheating to drying.

[0046] After the high-temperature hot air unit is running stably, the operating mode of the high-temperature hot air unit can be switched by adjusting the first air valve 19, the second air valve 20 and the third air valve 21. The operating modes of the high-temperature hot air unit include closed circulation mode or fresh air mode.

[0047] When switching to closed-loop mode, the second air valve 20 is opened, and the first air valve 19 and the third air valve 21 are closed. In closed-loop mode, the waste heat air discharged from the drying room is returned to the drying room after heat recovery through the evaporation pipe 17 and multi-stage heat exchange modules, which saves more than 30% energy compared to the traditional open waste heat recovery exhaust mode.

[0048] When switching to fresh air mode, the second air valve 20 is closed, and the first air valve 19 and the third air valve 21 are opened. In fresh air mode, fresh air enters the system after pre-absorbing the waste heat of the condensate pipe 16 and the evaporation pipe 17 through the fresh air total heat exchanger 1, reducing heat loss caused by direct introduction of fresh air and further improving energy-saving effect.

[0049] As for the changes in dehumidification and heating loads caused by mode switching, the high-temperature fixed-frequency compressor submodule can automatically add or remove loads, and then the low-temperature variable-frequency compressor submodule and the low-temperature fixed-frequency compressor submodule can automatically adjust the operating frequency to stabilize the required air outlet temperature.

[0050] Preferably, the control method further includes the following steps: acquiring the acid gas concentration value detected by the gas detection sensor 22; starting the alkaline sprayer 23 when the detected acid gas concentration value exceeds the concentration set value; and turning off the alkaline sprayer 23 when the detected acid gas concentration value is less than or equal to the concentration set value. The acid gas concentration set value can be 200ppm to 500ppm.

[0051] Preferably, when the alkali sprayer 23 is started, the high-temperature hot air unit switches to fresh air mode, and when the alkali sprayer 23 is turned off, the high-temperature hot air unit switches to closed-loop mode.

[0052] Preferably, the pH value of the condensate is obtained. When the pH value of the condensate is lower than the lower limit of the set range, the alkaline spray volume of the alkaline sprayer 23 is increased; when the pH value of the condensate is higher than the upper limit of the set range, the alkaline spray volume of the alkaline sprayer 23 is decreased. The set range for the pH value of the condensate can be 6.5~7.5. When the alkaline sprayer 23 is started, the initial spray volume can be controlled at 0.5-2L / h according to the concentration of acidic gas, and dynamically corrected in conjunction with the pH value of the condensate. When pH < 6.5, the spray volume is increased; when pH > 7.5, the spray volume is decreased, ensuring that the condensate is always in the neutral range of 6.5-7.5. This prevents acidic condensate from corroding the equipment and avoids the discharge of wastewater with excessive alkalinity, thus meeting environmental protection requirements.

[0053] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-temperature hot air unit for drying desulfurized gypsum board, characterized in that, Includes a fresh air total heat exchanger, a multi-stage heat exchange module, an air valve switching module, a first fan, and a second fan; The multi-stage heat exchange module includes a high-temperature fixed-frequency compressor submodule, a low-temperature variable-frequency compressor submodule, and a low-temperature fixed-frequency compressor submodule. The high-temperature fixed-frequency compressor submodule includes a high-temperature fixed-frequency compressor, a condenser, an electronic expansion valve, and an evaporator connected in series to form a circulation loop. The low-temperature variable-frequency compressor submodule includes a low-temperature variable-frequency compressor, a condenser, an electronic expansion valve, and an evaporator connected in series to form a circulation loop. The high-temperature fixed-frequency compressor submodule, the low-temperature variable-frequency compressor submodule, and the low-temperature fixed-frequency compressor submodule are connected in series via condensing pipes, and the high-temperature fixed-frequency compressor submodule, the low-temperature variable-frequency compressor submodule, and the low-temperature fixed-frequency compressor submodule are connected in series via evaporating pipes. The condensing pipes and the evaporating pipes are connected via switching pipes. The air inlet of the first fan is connected to the condenser pipe, and the air outlet of the second fan is connected to the evaporator pipe; the fresh air total heat exchanger is connected to both the condenser pipe and the evaporator pipe. The air valve switching module includes a first air valve, a second air valve, and a third air valve, which are respectively installed on the condensation pipe, the evaporation pipe, and the switching pipe. The evaporation pipe is further provided with a gas detection sensor, an alkaline sprayer and a vortex air chamber. The gas detection sensor is located at the air outlet of the evaporation pipe near the second fan and is connected to the alkaline sprayer. The alkaline sprayer is located on the upwind side of the vortex air chamber. The multi-stage heat exchange module includes at least two high-temperature fixed-frequency compressor sub-modules and at least two low-temperature fixed-frequency compressor sub-modules.

2. A control method for a high-temperature hot air unit for drying desulfurized gypsum board, applied to the high-temperature hot air unit for drying desulfurized gypsum board as described in claim 1, characterized in that, The control method includes the following steps: When starting the high-temperature hot air unit, turn on the first and second fans, start the low-temperature variable frequency compressor submodule and the low-temperature fixed frequency compressor submodule, open the second air valve, and close the first and third air valves. When the temperature of the drying chamber reaches the start-up set value of the high-temperature fixed-frequency press submodule, the high-temperature fixed-frequency press submodule is started. After the high-temperature hot air unit is running stably, the operating mode of the high-temperature hot air unit can be switched by adjusting the first air valve, the second air valve and the third air valve. The operating modes of the high-temperature hot air unit include closed circulation mode or fresh air mode. When switching to closed-loop mode, open the second air valve and close the first and third air valves; When switching to fresh air mode, close the second air valve and open the first and third air valves.

3. The control method for a high-temperature hot air unit for drying desulfurized gypsum board according to claim 2, characterized in that, The starting setting value for the high-temperature fixed-frequency compressor submodule is 50~60℃.

4. The control method for a high-temperature hot air unit for drying desulfurized gypsum board according to claim 2, characterized in that, The control method further includes the following steps: acquiring the acid gas concentration value detected by the gas detection sensor; starting the alkaline sprayer when the detected acid gas concentration value exceeds the concentration set value; and turning off the alkaline sprayer when the detected acid gas concentration value is less than or equal to the concentration set value.

5. The control method for a high-temperature hot air unit for drying desulfurized gypsum board according to claim 4, characterized in that, The acid gas concentration is set at 200ppm to 500ppm.

6. The control method for a high-temperature hot air unit for drying desulfurized gypsum board according to claim 4, characterized in that, When the alkali sprayer is started, the high-temperature hot air unit switches to fresh air mode; when the alkali sprayer is turned off, the high-temperature hot air unit switches to closed-loop mode.

7. The control method for a high-temperature hot air unit for drying desulfurized gypsum board according to claim 4, characterized in that, Obtain the pH value of the condensate. When the pH value of the condensate is less than the lower limit of the set range, increase the alkaline spray volume of the alkaline sprayer. When the pH value of the condensate is greater than the upper limit of the set range, decrease the alkaline spray volume of the alkaline sprayer.

8. The control method for a high-temperature hot air unit for drying desulfurized gypsum board according to claim 7, characterized in that, The pH value of the condensate is set within the range of 6.5 to 7.5.

Images