Low-temperature drying system with heat and cold balance adjustment function and balance adjustment method

Abstract

The application provides a low-temperature drying system and a balance adjustment method with heat and cold balance adjustment functions, which can adjust the actual supplied heat and cold according to the required heat and cold, realize accurate control of the heat and cold, and further improve the drying condensation effect and efficiency of the low-temperature drying system. In the low-temperature drying system, a hot water pump and a valve A are sequentially arranged on a hot water pipeline between a heat exchanger and a low-temperature drying system heat exchange module heater; a cold water pump and a valve B are sequentially arranged on a cooling water pipeline between a cooling tower and a low-temperature drying system heat exchange module cooler; a temperature and humidity sensor A is arranged on a return air pipeline of the heat exchange module and used for monitoring the temperature and humidity of return air; temperature and humidity sensors B are arranged on air inlet and outlet pipelines of the cooler and used for measuring the temperature and humidity of air before and after the cooler.

Description

Technical Field

[0001] This invention relates to a low-temperature drying system, specifically a low-temperature drying system with heat and cold balance adjustment functions, belonging to the field of sludge low-temperature drying technology. Background Technology

[0002] The heat source for heat-source type low-temperature drying equipment is generally hot water, which originates from steam heat exchange, flue gas heat exchange, or hot water heat exchange. The hot water is introduced into the heater of the low-temperature drying equipment, where it exchanges heat with the air outside the heater. The heated air is then used to dry the sludge. The cold source is typically a cooling tower. The cold water in the cooling tower enters the cooler of the dryer, where it exchanges heat with the air outside the cooler. Moisture in the air is condensed, thus achieving a dehumidification effect. The power for both hot water and cooling comes from circulating water pumps, which operate at a fixed frequency, with a constant flow rate for both hot and cold water.

[0003] The heat source type low-temperature drying equipment includes a drying chamber and a heat exchange module; its water circulation system includes hot water circulation and cooling water circulation, and the working principle of the water circulation system is as follows: Figure 1 As shown:

[0004] The hot water circulation process is as follows: An external heat source, such as steam, flue gas, or hot water, is introduced into the heat exchanger. Hot water at approximately 65°C (e.g., 70°C) from the heat exchange module of the low-temperature drying equipment is also introduced into the heat exchanger to exchange heat with the external heat source. After heat exchange, the temperature is approximately 85°C (e.g., 90°C). The heated hot water enters a hot water tank, which is connected to a hot water pump. The hot water pump, operating at a fixed frequency, delivers the hot water to the heater within the heat exchange module of the drying equipment. The hot water in the heater exchanges heat with the external dry, cold air, heating the dry, cold air to approximately 75°C to form dry, hot air. This dry, hot air then enters the drying chamber to dry the sludge. After heat exchange, the temperature of the hot water in the heater drops to approximately 65°C (e.g., 70°C) and re-enters the heat exchanger with the external heat source, thus completing the cycle.

[0005] The cooling water circulation process is as follows: Water exiting the heat exchange module of the low-temperature drying equipment, with a temperature of approximately 40℃ (e.g., 45℃), flows into an open or closed cooling tower, where it is cooled to approximately 30℃ (e.g., 33℃). A cooling water pump, operating at a fixed frequency, then delivers the cooling water to the cooler within the heat exchange module of the low-temperature drying equipment. The air temperature outside the cooler is approximately 45℃; after cooling, the air temperature drops to approximately 35℃, forming humid, cold air. At this point, the air is saturated with humidity, and most of the moisture in the air condenses, achieving dehumidification. After heat exchange with the outside air, the water inside the cooler reaches a temperature of approximately 40℃ (e.g., 45℃) and re-enters the cooling tower for further cooling, thus completing the cycle.

[0006] However, existing heat source-type low-temperature drying equipment does not adjust its heating and cooling methods according to the changes in temperature throughout the four seasons, resulting in different demands for heat and cooling (for the same water output, the lower temperature in winter leads to higher heat demand, while the higher temperature in summer reduces cooling efficiency and requires a larger water flow). This causes a mismatch between the demanded heat and cooling capacity and the actual supply, making the temperature of the hot air and the condensation temperature uncontrollable, thus failing to achieve a good drying and condensation effect. At the same time, the amount and moisture content of the incoming mud also change, altering the demand for heat and cooling. Currently, heat source-type low-temperature drying equipment cannot adjust its operating conditions according to the amount and moisture content of the incoming mud, thus failing to achieve a good drying and condensation effect. Summary of the Invention

[0007] In view of this, the present invention provides a low-temperature drying system with heat and cold balance adjustment function, which can adjust the actual heat and cold supply according to the required heat and cold, realize precise control of heat and cold, and thus improve the drying and condensation effect and efficiency of the low-temperature drying system.

[0008] The technical solution of the present invention is: a low-temperature drying system with heat and cold balance adjustment function, including a heat and cold balance adjustment unit; the heat and cold balance adjustment unit includes: valve A, temperature and humidity sensor A, valve B, and temperature and humidity sensor B;

[0009] A hot water pump and valve A are sequentially installed on the hot water pipeline between the heat exchanger and the heater of the heat exchange module in the low-temperature drying system; a cold water pump and valve B are sequentially installed on the cooling water pipeline between the cooling tower and the cooler of the heat exchange module in the low-temperature drying system.

[0010] A temperature and humidity sensor A is installed on the return air duct of the heat exchange module to monitor the temperature and humidity of the return air;

[0011] Temperature and humidity sensors B are installed on the air inlet and outlet ducts of the cooler to measure the temperature and humidity of the air before and after the cooler.

[0012] In a preferred embodiment of the present invention, both the hot water pump and the cold water pump are variable frequency pumps.

[0013] In a preferred embodiment of the present invention, the low-temperature drying system includes several heat exchange units, and each heat exchange unit includes several heat exchange modules;

[0014] The hot water outlet pipe of the heat exchanger is divided into several hot water branch pipes corresponding to the heat exchange modules after passing through the hot water pump. Each hot water branch pipe is equipped with a valve A, and the hot water branch pipe is connected to the heater in the corresponding heat exchange module.

[0015] The cooling water outlet pipe of the cooling tower is divided into several cooling water branch pipes after passing through the cold water pump. Each cooling water branch pipe is equipped with a valve B, and the cooling water branch pipe is connected to the cooler in the corresponding heat exchange module.

[0016] In a preferred embodiment of the present invention, the low-temperature drying system includes several heat exchange units, and each heat exchange unit includes several heat exchange modules;

[0017] In the heat exchange unit, heat exchange modules located at the same height are grouped together, thereby dividing the heat exchange unit into n groups, where n is an integer greater than or equal to 1;

[0018] The hot water outlet pipe of the heat exchanger is divided into n hot water branch pipes after passing through the hot water pump. Each hot water branch pipe is equipped with valve A and is further connected to the heater of the heat exchange module in that group.

[0019] The cooling water outlet pipe of the cooling tower is divided into n cooling water branch pipes after passing through the cold water pump. Each cooling water branch pipe is equipped with a valve B and is further connected to the cooler of the heat exchange module in that group.

[0020] In a preferred embodiment of the present invention, the hot and cold balance adjustment unit further includes a control unit, wherein the hot water pump, the cold water pump, valve A, and valve B are all controlled by the control unit.

[0021] In addition, the present invention also provides a method for adjusting the heat and cold balance of a low-temperature drying system. The method monitors the return air temperature of the heat exchange module of the low-temperature drying system in real time. If the monitored return air temperature is lower than a preset return air temperature range, the hot water flow rate provided by the heat exchanger is increased until the return air temperature reaches the preset return air temperature range. If the monitored return air temperature is higher than the preset return air temperature range, the hot water flow rate provided by the heat exchanger is reduced until the return air temperature drops to the set return air temperature range, thereby achieving heat balance regulation.

[0022] The temperature and humidity of the air entering and exiting the cooler in the heat exchange module of the low-temperature drying system are monitored in real time to obtain the moisture content of the air before and after the cooler. The difference between the moisture content of the air before and after the cooler is obtained as the moisture content difference value. If the moisture content difference value is lower than the preset unit air water removal range, the cooling water flow rate provided by the cooling tower is increased until the moisture content difference value reaches the set unit air water removal range. If the moisture content difference value is greater than the set unit air water removal range, the cooling water flow rate provided by the cooling tower is decreased until the moisture content difference value reaches the set water removal range, thereby achieving a balanced regulation of cooling capacity.

[0023] In a preferred embodiment of the present invention, the hot water flow rate is adjusted by regulating valve A on the hot water pipeline located between the heat exchanger and the heater;

[0024] The cooling water flow rate is adjusted by regulating valve B on the cooling water pipeline located between the cooling tower and the cooler.

[0025] In a preferred embodiment of the present invention, a variable frequency hot water pump is installed on the hot water pipeline. When the hot water flow rate is increased, if the return air temperature is still lower than the preset return air temperature range even when the valve A is adjusted to the maximum, the frequency of the variable frequency hot water pump is increased until the return air temperature reaches the preset return air temperature range.

[0026] A variable frequency chilled water pump is installed on the cooling water pipeline. When the cooling water flow rate is increased, if the moisture content difference is still lower than the set unit air water removal range when valve B is adjusted to the maximum, the frequency of the variable frequency chilled water pump is increased until the moisture content difference reaches the set unit air water removal range.

[0027] Beneficial effects:

[0028] (1) The present invention sets up a heat and cold balance adjustment unit in the low temperature drying system. The heat and cold balance adjustment unit realizes the dynamic adjustment of heat and cold. Specifically, the return air temperature is linked with the proportional regulating valve control and the frequency conversion control of the hot water pump. The actual heat demand of the sludge is judged according to the return air temperature to achieve the matching of heat demand and actual heat supply. The temperature and humidity before and after the cooler are detected and the moisture content of the unit air is calculated to calculate the amount of water to be removed. The amount of water to be removed is linked with the proportional regulating valve control and the frequency conversion control of the cooling water pump to achieve the matching of cooling demand and actual cooling supply. This can solve the impact of seasonal temperature changes and changes in sludge sludge content and moisture content, so that the heat and cold demand are matched with the actual heat and cold supply, thereby improving the utilization efficiency of heat and cold and improving the sludge drying effect.

[0029] (2) In this invention, the cold and heat balance adjustment unit can control the amount of water removed according to the temperature changes in the four seasons and the changes in sludge content and moisture content, thereby ensuring the sludge drying effect and improving the drying efficiency.

[0030] (3) In this invention, considering that the low temperature drying system usually includes several heat exchange units, and each heat exchange unit includes several modules, the actual use requires different amounts of heat and cold energy for each heat exchange module. By independently controlling each heat exchange module, the low temperature drying system can be precisely controlled, thereby improving the sludge drying effect.

[0031] (4) In this invention, considering that the low temperature drying system usually includes several heat exchange units, and each heat exchange unit includes several modules, in actual use, in order to simplify the control method, the heat exchange modules located at the same height in the heat exchange unit are grouped together, and the heat exchange modules in each heat exchange unit are controlled in groups. Attached Figure Description

[0032] Figure 1 A schematic diagram illustrating the working principle of hot water circulation and cooling water circulation in a traditional heat source type low-temperature drying system;

[0033] Figure 2 This is a schematic diagram of the hot water circulation and cooling water circulation systems with heat and cold balance adjustment functions according to the present invention.

[0034] Figure 3 This is a schematic diagram of the hot water circulation and cooling water circulation of the heat source type low-temperature drying system in Example 2.

[0035] Among them: 1-heat exchanger, 2-variable frequency hot water pump, 3-proportional regulating valve A, 4-cooler, 5-heater, 6-proportional regulating valve B, 7-variable frequency cold water pump, 8-cooling tower, 9-temperature and humidity sensor A, 10-temperature and humidity sensor B, 11-heat exchange module. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0037] Example 1:

[0038] This embodiment provides a low-temperature drying system with heat and cold balance adjustment function. By real-time monitoring of the operating conditions of the low-temperature drying system, the actual heat and cold supply can be adjusted according to the required heat and cold, especially the heat balance adjustment according to the different seasons of spring, summer, autumn and winter, as well as the changes in the amount and moisture content of the incoming mud; thus achieving precise control of heat and cold, thereby improving the drying and condensation effect and efficiency of the low-temperature drying system.

[0039] like Figure 2 As shown, the low-temperature drying system is equipped with a heat and cold balance adjustment unit, which enables dynamic adjustment of heat and cold to match the required heat and cold with the actual heat and cold supplied.

[0040] The heat and cold balance adjustment unit includes: two variable frequency water pumps, a proportional control valve A3, a temperature and humidity sensor A9, a proportional control valve B6, a temperature and humidity sensor B10, and a control unit.

[0041] The hot water pump between heat exchanger 1 and heater 5 of the low-temperature drying system heat exchange module 11 is a variable frequency pump (usually two are installed, one as a backup). Similarly, the cooling water pump between cooling tower 8 and cooler 4 of the low-temperature drying system heat exchange module 11 is also a variable frequency pump (usually two are installed, one as a backup). Specifically, heat exchanger 1 is connected to heater 5 inside heat exchange module 11 via a hot water pipeline containing a hot water tank and a variable frequency pump (let's call it variable frequency hot water pump 2). Cooling tower 8 is connected to cooler 4 inside heat exchange module 11 via a cooling water pipeline containing a variable frequency pump (let's call it variable frequency cold water pump 7). Both variable frequency hot water pump 2 and variable frequency cold water pump 7 are controlled by a control unit.

[0042] A valve (for example, a proportional control valve A3) is installed between the variable frequency hot water pump 2 and the heater 5 on the hot water pipeline to control the flow rate of hot water in the hot water pipeline; a valve (for example, a proportional control valve B6) is installed between the variable frequency cold water pump 7 and the cooler 4 on the cooling water pipeline to control the flow rate of cooling water in the cooling water pipeline; both the proportional control valve A3 and the proportional control valve B6 are three-way proportional valves and are controlled by the control unit.

[0043] In addition, a temperature and humidity sensor A9 is installed on the return air duct of the heat exchange module 11 (usually located at the return air inlet of the drying chamber) to monitor the temperature and humidity of the return air and send the data to the control unit. The return air temperature is linked to the proportional control valve A3 (i.e., linked to the hot water flow): the control unit has a preset return air temperature range (this temperature range is determined based on the drying rate curve and the design operating point; if it is below the minimum value, the drying rate will be very low, and the system's drying capacity will not be reached; if it is above the maximum value, the system's energy consumption will be very high, and operation will be uneconomical). If the return air temperature monitored by the temperature and humidity sensor A9 is lower than the preset temperature range (i.e., the return air temperature is less than the minimum value of the preset return air temperature range), it indicates that the heat provided by the hot water in the heat exchanger 1 is insufficient to meet the current drying requirements (when the return air temperature is low, it indicates a high heat demand; if the hot water flow is not adjusted at this time, the reheating temperature of the return air will be lower than the design operating point), and the heat needs to be increased; based on this, the control unit controls the proportional control valve A3. The proportional control valve A3 increases the flow rate of hot water entering the heater 5 (i.e., increases the heat). If the flow rate of this passage of the proportional control valve A3 is adjusted to the maximum, and the return air temperature is still lower than the preset return air temperature range, the control unit adjusts the frequency of the variable frequency hot water pump 2 to increase the frequency of the variable frequency hot water pump 2 until the return air temperature reaches the preset return air temperature range. If the return air temperature monitored by the temperature and humidity sensor A9 is higher than the preset return air temperature range (i.e., the return air temperature is higher than the highest value of the preset return air temperature range), it indicates that the heat provided by the heat exchanger 1 is greater than the heat required for the current drying. Therefore, the heat supply needs to be reduced. Based on this, the control unit controls the proportional control valve A3 to reduce the flow rate of hot water entering the heater 5 (i.e., reduces the heat) until the return air temperature drops to the set return air temperature range.

[0044] Meanwhile, temperature and humidity sensors B10 are installed on both the inlet and outlet air ducts of the cooler 4 to measure the temperature and humidity of the air before and after the cooler 4 and send the data to the control unit for dynamic adjustment of the cooling capacity. Specifically, the control unit obtains the moisture content of the air before and after the cooler 4 by referring to a table based on the temperature and humidity of the air before and after the cooler 4 monitored by the temperature and humidity sensors B10 (existing technology). Then, the moisture content of the air before and after the cooler 4 is subtracted to obtain the moisture content difference value. This moisture content difference value is the amount of water removed from the sludge by the air after passing through the drying chamber. This moisture content difference value is compared with the preset unit air water removal range. If the moisture content difference value is lower than the preset unit air water removal range (i.e., the moisture content difference value is less than the minimum value of the preset unit air water removal range), it indicates that the cooling capacity provided by the cooling tower 8 is not sufficient for the current drying process. If cooling capacity is required, the cooling capacity needs to be increased. Based on this, the control unit controls the proportional regulating valve B6 to increase the flow rate of chilled water entering the cooler 4 (i.e., increase the cooling capacity). If the flow rate of this passage of the proportional regulating valve B is adjusted to the maximum, and the moisture content difference is still lower than the set unit air water removal range, the control unit adjusts the frequency of the variable frequency chilled water pump 7 to increase the frequency of the variable frequency chilled water pump 7 until the moisture content difference reaches the set unit air water removal range. If the moisture content difference is greater than the set unit air water removal range (i.e., the moisture content difference is greater than the maximum value of the preset unit air water removal range), it indicates that the cooling capacity provided by the cooling tower 8 is greater than the cooling capacity required for the current drying process. Therefore, the cooling capacity provided needs to be reduced. Based on this, the control unit controls the proportional regulating valve B to reduce the flow rate of chilled water entering the cooler 4 (i.e., reduce the cooling capacity) until the moisture content difference reaches the set unit air water removal range.

[0045] Adjust the unit air dewatering range according to the amount of mud and the moisture content of the mud.

[0046] Therefore, the heat and cold balance adjustment unit dynamically regulates heat and cold in real time, determines the actual heat demand of the sludge based on the return air temperature, and achieves a match between the heat demand and the actual heat supply; it calculates the actual water removal amount per unit of air for the sludge based on the difference in moisture content of the air before and after the cooler 4, and compares it with the required water removal amount per unit of air (or the actual water removal amount can be calculated based on the difference in moisture content of the air before and after the cooler 4 and the airflow (which can be calculated by setting a wind speed sensor), and compares it with the required water removal amount), thus achieving a match between the cooling demand and the actual cooling supply. This solves the problems caused by seasonal temperature changes and changes in sludge quantity and moisture content, matching the heat demand with the actual heat supply, improving heat utilization efficiency, and enhancing the sludge drying effect.

[0047] Example 2:

[0048] Based on the above embodiment 1, further considering that the low temperature drying system usually includes several heat exchange units, and each heat exchange unit includes several heat exchange modules 11 (each heat exchange module includes a heater 5 and a cooler 4); in actual use, the heat and cold demand of each heat exchange module 11 is different. In order to achieve precise control of each heat exchange module 11 in different areas, each heat exchange module 11 is controlled independently.

[0049] As an example, the low-temperature drying system includes five heat exchange units, each of which includes four heat exchange modules 11; such as Figure 3 As shown, taking one heat exchange unit as an example: the hot water outlet pipe of the external heat exchanger 1, after passing through the variable frequency hot water pump 2, divides into four hot water branch pipes corresponding to the heat exchange module 11 at the location of the heat exchange unit. Each hot water branch pipe is equipped with a proportional regulating valve A3, and the hot water branch pipe is connected to the heater 5 of the corresponding heat exchange module 11. The proportional regulating valve A3 on each hot water branch pipe is used to control the flow rate of hot water in the corresponding hot water branch pipe.

[0050] The cooling water outlet pipe of cooling tower 8, after passing through variable frequency chilled water pump 7, branches into four cooling water branch pipes corresponding to heat exchange modules 11 at the location of the heat exchange unit. Each cooling water branch pipe is equipped with a proportional regulating valve B6, and the cooling water branch pipe is connected to the cooler 4 in the corresponding heat exchange module 11. The proportional regulating valve B6 on each cooling water branch pipe is used to control the flow rate of cooling water in the corresponding cooling water branch pipe.

[0051] Each heat exchange unit has a corresponding return air vent. A temperature and humidity sensor A9 is installed at the return air vent of each heat exchange unit to monitor the temperature and humidity of the return air vent of the corresponding heat exchange unit and send the data to the control unit. Each heat exchange module 11 in the corresponding heat exchange unit in the control unit has a preset return air temperature range. Thus, the control unit can dynamically regulate the heat of each heat exchange module 11, thereby achieving precise control of the heat of each heat exchange module 11.

[0052] Temperature and humidity sensors B10 are installed on the pipes before and after the cooler 4 (i.e., the air inlet and outlet pipes of the cooler) in each heat exchange module 11 to measure the temperature and humidity of the air before and after the cooler 4 and send it to the control unit. Each heat exchange module 11 in the corresponding heat exchange unit in the control unit has a preset unit air water removal range. Thus, the control unit can dynamically regulate the cooling capacity of each heat exchange module 11, thereby achieving precise control of the cooling capacity of each heat exchange module 11.

[0053] Example 3:

[0054] Considering that a low-temperature drying system typically includes several heat exchange units, each heat exchange unit contains several heat exchange modules 11 (each heat exchange module includes a heater 5 and a cooler 4); in actual use, to simplify the control method, the heat exchange modules 11 in each heat exchange unit are grouped for control.

[0055] As an example, the low-temperature drying system includes five heat exchange units, each of which includes four heat exchange modules 11; the four heat exchange modules 11 are arranged in two rows and two columns, thus grouping the two upper heat exchange modules 11 into one group and the two lower heat exchange modules 11 into another group; based on this:

[0056] The hot water outlet pipe of the external heat exchanger 1 is divided into two hot water branch pipes after passing through the variable frequency hot water pump 2 to each heat exchange unit. Each hot water branch pipe is equipped with a proportional regulating valve A3 and is further divided into two paths, which are respectively connected to the heater 5 of the heat exchange module 11 in the group.

[0057] After passing through the variable frequency chilled water pump 7, the cooling water outlet pipe of the cooling tower 8 splits into two cooling water branch pipes at each heat exchange unit. Each cooling water branch pipe is equipped with a proportional regulating valve B6 and then further splits into two paths, which are respectively connected to the cooler 4 of the heat exchange module 11 in that group.

[0058] Each heat exchange unit has a corresponding return air vent. A temperature and humidity sensor A9 is installed at the return air vent of each heat exchange unit to monitor the temperature and humidity of the return air vent of the corresponding heat exchange unit and send the data to the control unit. Each heat exchange module 1 in the corresponding heat exchange unit in the control unit has a preset return air temperature range, so the control unit can dynamically regulate the heat of each heat exchange module 1.

[0059] Temperature and humidity sensors B10 are installed on the pipes before and after the cooler 4 (i.e., the air inlet and outlet pipes of the cooler) in each heat exchange module 11 to measure the temperature and humidity of the air before and after the cooler 4 and send it to the control unit. Each heat exchange module in the corresponding heat exchange unit in the control unit has a preset unit air water removal range, so the control unit can dynamically adjust the cooling capacity of each heat exchange module.

[0060] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for adjusting the heat and cold balance of a low-temperature drying system, characterized in that: A low-temperature drying system with heat and cold balance adjustment function is adopted. The low-temperature drying system includes a heat and cold balance adjustment unit. The heat and cold balance adjustment unit includes: valve A, temperature and humidity sensor A, valve B, and temperature and humidity sensor B. A hot water pump and valve A are sequentially installed on the hot water pipeline between the heat exchanger and the heater of the heat exchange module in the low-temperature drying system; a cold water pump and valve B are sequentially installed on the cooling water pipeline between the cooling tower and the cooler of the heat exchange module in the low-temperature drying system. A temperature and humidity sensor A is installed on the return air duct of the heat exchange module to monitor the temperature and humidity of the return air; Temperature and humidity sensors B are installed on both the inlet and outlet air ducts of the cooler to measure the temperature and humidity of the air before and after the cooler. The temperature and humidity sensor A monitors the return air temperature of the heat exchange module of the low-temperature drying system in real time. If the monitored return air temperature is lower than the preset return air temperature range, the hot water flow rate provided by the heat exchanger is increased until the return air temperature reaches the preset return air temperature range. If the monitored return air temperature is higher than the preset return air temperature range, the hot water flow rate provided by the heat exchanger is reduced until the return air temperature drops to the preset return air temperature range, thereby achieving heat balance regulation. The temperature and humidity sensor B monitors the temperature and humidity of the air entering and exiting the cooler in the heat exchange module of the low-temperature drying system in real time, and obtains the moisture content of the air before and after the cooler. The difference between the moisture content of the air before and after the cooler is obtained as the moisture content difference value. If the moisture content difference value is lower than the preset unit air water removal range, the cooling water flow rate provided by the cooling tower is increased until the moisture content difference value reaches the preset unit air water removal range. If the moisture content difference value is greater than the preset unit air water removal range, the cooling water flow rate provided by the cooling tower is decreased until the moisture content difference value reaches the preset unit air water removal range, thereby achieving a balanced adjustment of the cooling capacity. The hot water flow rate is adjusted by regulating valve A on the hot water pipeline located between the heat exchanger and the heater; The cooling water flow rate is adjusted by regulating valve B, which is installed on the cooling water pipeline between the cooling tower and the cooler. Both the hot water pump and the cold water pump are variable frequency pumps. When increasing the hot water flow rate, if valve A is adjusted to the maximum and the return air temperature is still lower than the preset return air temperature range, the frequency of the hot water pump is increased until the return air temperature reaches the preset return air temperature range. When increasing the cooling water flow rate, if valve B is adjusted to the maximum and the moisture content difference is still lower than the preset unit air water discharge range, the frequency of the cold water pump is increased until the moisture content difference reaches the preset unit air water discharge range.

2. The method for adjusting the heat and cold balance of a low-temperature drying system as described in claim 1, characterized in that: The low-temperature drying system includes several heat exchange units, and each heat exchange unit includes several heat exchange modules; The hot water outlet pipe of the heat exchanger is divided into several hot water branch pipes corresponding to the heat exchange modules after passing through the hot water pump. Each hot water branch pipe is equipped with a valve A, and the hot water branch pipe is connected to the heater in the corresponding heat exchange module. The cooling water outlet pipe of the cooling tower is divided into several cooling water branch pipes after passing through the cold water pump. Each cooling water branch pipe is equipped with a valve B, and the cooling water branch pipe is connected to the cooler in the corresponding heat exchange module.

3. The method for adjusting the heat and cold balance of a low-temperature drying system as described in claim 1, characterized in that: The low-temperature drying system includes several heat exchange units, and each heat exchange unit includes several heat exchange modules; In the heat exchange unit, heat exchange modules located at the same height are grouped together, thereby dividing the heat exchange unit into n groups, where n is an integer greater than or equal to 1; The hot water outlet pipe of the heat exchanger is divided into n hot water branch pipes after passing through the hot water pump. Each hot water branch pipe is equipped with valve A and is further connected to the heater of the heat exchange module in that group. The cooling water outlet pipe of the cooling tower is divided into n cooling water branch pipes after passing through the cold water pump. Each cooling water branch pipe is equipped with a valve B and is further connected to the cooler of the heat exchange module in that group.

4. The method for adjusting the heat and cold balance of a low-temperature drying system as described in any one of claims 1-3, characterized in that: The hot and cold balance adjustment unit also includes a control unit, and the hot water pump, cold water pump, valve A, and valve B are all controlled by the control unit.

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