Waste heat recovery system for water-cooled air compressor

Abstract

The utility model discloses a waste heat recovery system for a water-cooled air compressor, which comprises the water-cooled air compressor, a cooling tower, a heat exchange element, a hot water user side, a circulating pump set I and a circulating pump set II, and a cooling water outlet of the water-cooled air compressor is connected with a heating medium inlet of the heat exchange element through a cooling water return main pipe I; a heating medium outlet of the heat exchange element is connected with the water return end of the cooling tower through a second cooling water return main pipe, the water outlet end of the cooling tower is connected with a cooling water inlet of the water-cooled air compressor through a cooling water inlet main pipe, and a first circulating pump set is arranged on the cooling water inlet main pipe. A refrigerant inlet of the heat exchange element is externally connected with industrial water through a second circulating pump set and a pipeline, and a refrigerant outlet of the heat exchange element is connected with a hot water user side through a pipeline. High-temperature cooling water from the water-cooled air compressor exchanges heat with low-temperature industrial water in the heat exchange element, burden is relieved for the cooling tower, the industrial water with the increased temperature is conveyed to a hot water user side to be used, and heat energy waste is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of waste heat recovery equipment, in particular to a waste heat recovery system for a water-cooled air compressor. Background Art

[0002] A water-cooled air compressor is a compressor whose cylinder is cooled by water. Its cylinder (including cylinder block, cylinder head, cylinder seat, etc.) is equipped with a water jacket for cooling water circulation. When the water-cooled air compressor is running, the cooling water flowing in the water jacket continuously takes away part of the heat of the compressed gas in the cylinder, thereby reducing the compressor exhaust temperature and power consumption and cooling the cylinder, so that the cylinder wall maintains a certain temperature range to ensure the normal operation of the compressor.

[0003] At present, in many processes of thermal power plants, such as boiler flue gas denitrification ammonia water spray gun atomization, power plant pneumatic valves and instrument drives, coal bunker air cannons, boiler pneumatic ash conveying to ash storage bins and other operating processes, high-pressure compressed air is required as a carrier gas to ensure the normal operation of each process. Since water-cooled air compressors generate a large amount of heat in the process of compressing air, in order to meet the normal working requirements of water-cooled air compressors, it is usually necessary to equip circulating cooling water to circulate and cool the water-cooled air compressor. The cooling water flowing out of the water-cooled air compressor contains a large amount of heat. This part of heat is usually discharged into the air through a cooling tower, which not only causes atmospheric thermal radiation pollution but also wastes a large amount of low-quality heat energy. Therefore, the utility model proposes a waste heat recovery system for water-cooled air compressors, in order to recycle and utilize a large amount of heat in the cooling water flowing out of the water-cooled air compressor. Summary of the invention

[0004] The purpose of the utility model is to overcome the defects in the prior art and provide a waste heat recovery system for a water-cooled air compressor. The system achieves the effect of lowering the temperature of the cooling water and raising the temperature of the industrial water by exchanging heat between the high-temperature cooling water from the water-cooled air compressor and the low-temperature industrial water inside the heat exchange element, so that the temperature of the cooling water returning to the cooling tower will not be too high, thereby effectively reducing the heat discharged into the atmosphere by the cooling tower, reducing or eliminating the thermal radiation pollution to the atmosphere, and reducing the burden on the cooling tower. At the same time, the industrial water with increased temperature is transported to the hot water user end for use, so that the heat in the cooling water can be effectively recovered and utilized, effectively reducing the waste of heat energy, and meeting the requirements of energy conservation and emission reduction; the overall structural design is simple, the application implementation feasibility is high, and the practicability is strong.

[0005] To achieve the above-mentioned purpose, the technical solution of the utility model is a waste heat recovery system designed for a water-cooled air compressor, including a water-cooled air compressor, a cooling tower, a heat exchange element, a hot water user end, a circulating pump group 1 and a circulating pump group 2. The cooling water outlet of the water-cooled air compressor is connected to the heat medium inlet of the heat exchange element through a cooling water return pipe 1, the heat medium outlet of the heat exchange element is connected to the return end of the cooling tower through a cooling water return pipe 2, the water outlet end of the cooling tower is connected to the cooling water inlet of the water-cooled air compressor through a cooling water inlet pipe, a circulating pump group 1 is provided on the cooling water inlet pipe, the refrigerant inlet of the heat exchange element is connected to industrial water through a circulating pump group 2 and a pipeline, and the refrigerant outlet of the heat exchange element is connected to the hot water user end through a pipeline.

[0006] The waste heat recovery system for a water-cooled air compressor of the utility model achieves the effect of lowering the temperature of the cooling water and raising the temperature of the industrial water by exchanging heat between the high-temperature cooling water from the water-cooled air compressor and the low-temperature industrial water inside the heat exchange element, so that the temperature of the cooling water returning to the cooling tower will not be too high, thereby effectively reducing the heat discharged from the cooling tower to the atmosphere, reducing or eliminating the thermal radiation pollution to the atmosphere, and reducing the burden on the cooling tower. At the same time, the industrial water with increased temperature is transported to the hot water user end for use, so that the heat in the cooling water can be effectively recovered and utilized, effectively reducing the waste of heat energy, and meeting the requirements of energy conservation and emission reduction; the overall structural design is simple, the application implementation feasibility is high, and the practicability is strong.

[0007] The preferred technical solution is that a cooling water return bypass pipe is provided between the cooling water return main pipe 1 and the cooling water return main pipe 2, a valve body 1 is provided on the cooling water return bypass pipe, a temperature sensor is provided at the refrigerant outlet of the heat exchange element, the valve body 1 and the temperature sensor are both electrically connected to the control system, and the valve body 1 and the temperature sensor are controlled in linkage, a valve body 2 is provided at the outlet end of the cooling water return main pipe 1, and a valve body 3 is provided at the inlet end of the cooling water return main pipe 2. When the hot water user has strict requirements for the required hot water temperature, the temperature sensor feeds back the temperature signal to the control system in real time. When the temperature of the hot water discharged from the heat exchange element is too high, the control system sends a command to the valve body 1 to increase the opening degree to reduce the high-temperature cooling water flow rate from the cooling water return pipe 1 entering the heat exchange element, so that part of the water in the cooling water return pipe 1 enters the cooling water return pipe 2 through the cooling water return bypass pipe. Conversely, when the temperature of the hot water discharged from the heat exchange element is too low, the control system sends a command to the valve body 1 to reduce the opening degree to increase the high-temperature cooling water flow rate from the cooling water return pipe 1 entering the heat exchange element, so as to achieve the purpose of real-time regulation of the temperature of the hot water discharged from the heat exchange element; when the heat exchange element fails, the valve body 1 can be fully opened, and the valve bodies 2 and 3 can be closed, so that the cooling water can circulate normally in the water-cooled compressor to ensure the normal operation of the water-cooled compressor.

[0008] A further preferred technical solution also includes a desalted water tank, wherein the refrigerant inlet of the heat exchange element is connected to the water outlet of the desalted water tank through a circulating pump group 2 and a pipeline, and the water inlet of the desalted water tank is externally connected to industrial water. The desalted water tank can effectively filter out impurities such as metal ions in industrial water, reduce the hardness of industrial water, help reduce scaling inside the heat exchange element, and extend the service life of the heat exchange element.

[0009] A further preferred technical solution is that the heat exchange element includes an evaporator and a condenser, the cooling water outlet of the water-cooled air compressor is connected to the shell side inlet of the evaporator through a cooling water return pipe 1, the shell side outlet of the evaporator is connected to the return water end of the cooling tower through a cooling water return pipe 2, the refrigerant inlet of the condenser is connected to the water outlet of the desalted water tank through a circulating pump group 2 and a pipeline, and the refrigerant outlet of the condenser is connected to the hot water user end through a pipeline. The heat exchange element has an ingenious and reasonable structural design, good heat exchange effect, and can fully exchange heat with the high-temperature cooling water from the water-cooled air compressor to reduce the temperature of the cooling water, thereby realizing full recovery of heat in the cooling water.

[0010] A further preferred technical solution is that the heat exchange element is a coil heat exchanger, the water inlet end of the coil inside the heat exchange element is connected to the water outlet of the desalted water tank through the circulation pump group 2 and the pipeline, and the water outlet end of the coil inside the heat exchange element is connected to the hot water user end through the pipeline. The coil heat exchanger has a simple structure, strong universality, and good economy, ensuring that the waste heat recovery system for water-cooled air compressors of the utility model can be smoothly prepared and implemented.

[0011] A further preferred technical solution is that the circulating pump group 1 and the circulating pump group 2 each include at least two circulating pumps arranged in parallel, so as to achieve the purpose of one for backup and one for use, and ensure that the waste heat recovery system for the water-cooled air compressor of the utility model can be smoothly operated.

[0012] The advantages and beneficial effects of the utility model are:

[0013] 1. The waste heat recovery system for a water-cooled air compressor of the utility model exchanges heat between the high-temperature cooling water from the water-cooled air compressor and the low-temperature industrial water inside the heat exchange element, thereby achieving the effect of lowering the temperature of the cooling water and raising the temperature of the industrial water, so that the temperature of the cooling water returning to the cooling tower will not be too high, thereby effectively reducing the heat discharged into the atmosphere by the cooling tower, reducing or eliminating the thermal radiation pollution to the atmosphere, and reducing the burden on the cooling tower. At the same time, the industrial water with increased temperature is transported to the hot water user end for use, so that the heat in the cooling water can be effectively recovered and utilized, effectively reducing the waste of heat energy, and meeting the requirements of energy conservation and emission reduction; the overall structural design is simple, the application implementation feasibility is high, and the practicability is strong.

[0014] 2. When the hot water user has strict requirements for the required hot water temperature, the temperature sensor will feed back the temperature signal to the control system in real time. When the temperature of the hot water discharged from the heat exchange element is too high, the control system will issue a command to increase the opening degree to the valve body 1 to reduce the high-temperature cooling water flow rate from the cooling water return pipe 1 entering the heat exchange element, so that part of the water in the cooling water return pipe 1 enters the cooling water return pipe 2 through the cooling water return bypass pipe. On the contrary, when the temperature of the hot water discharged from the heat exchange element is too low, the control system will issue a command to reduce the opening degree to the valve body 1 to increase the high-temperature cooling water flow rate from the cooling water return pipe 1 entering the heat exchange element, so as to achieve the purpose of real-time regulation of the temperature of the hot water discharged from the heat exchange element; when the heat exchange element fails, the valve body 1 can be fully opened, and the valve bodies 2 and 3 can be closed, so that the cooling water can circulate normally in the water-cooled compressor to ensure the normal operation of the water-cooled compressor.

[0015] 3. The desalted water tank can effectively filter out impurities such as metal ions in industrial water, reduce the hardness of industrial water, help reduce scaling inside the heat exchange element, and extend the service life of the heat exchange element.

[0016] 4. The hot water in the hot water user end can be used as bathroom water, heating heat medium, and can also be used to preheat the water for steam boilers, thereby reducing the consumption of energy such as natural gas and coal, and meeting energy-saving and environmental protection requirements.

[0017] 5. The waste heat recovery system for a water-cooled air compressor of the utility model is economical and efficient, energy-saving and environmentally friendly, has precise control, is safe and reliable, and is easy to promote and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a structural schematic diagram of a waste heat recovery system for a water-cooled air compressor in Example 1;

[0019] Figure 2 It is a structural schematic diagram of a waste heat recovery system for a water-cooled air compressor in Example 2.

[0020] In the figure: 1. Water-cooled air compressor; 2. Cooling tower; 3. Heat exchange element; 4. Hot water user end; 5. Circulation pump group 1; 6. Circulation pump group 2; 7. Desalted water tank; 3-1. Evaporator; 3-2. Condenser; 3-3. Coil; a. Cooling water return main pipe 1; b. Cooling water return main pipe 2; c. Cooling water return bypass pipe; d. Valve body 1; e. Valve body 2; f. Valve body 3; g. Temperature sensor; h. Cooling water inlet main pipe. DETAILED DESCRIPTION

[0021] The following is a further description of the specific implementation of the present invention in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0022] Example 1

[0023] like Figure 1 As shown, a waste heat recovery system for a water-cooled air compressor comprises a water-cooled air compressor 1, a cooling tower 2, a heat exchange element 3, a hot water user end 4, a circulating pump group 1 5 and a circulating pump group 2 6, the cooling water outlet of the water-cooled air compressor 1 is connected to the heat medium inlet of the heat exchange element 3 through a cooling water return pipe 1 a, the heat medium outlet of the heat exchange element 3 is connected to the return end of the cooling tower 2 through a cooling water return pipe 2 b, the water outlet of the cooling tower 2 is connected to the cooling water inlet of the water-cooled air compressor 1 through a cooling water inlet pipe h, the cooling water inlet pipe h is provided with a circulating pump group 1 5, the refrigerant inlet of the heat exchange element 3 is connected to industrial water through a circulating pump group 2 6 and a pipeline, and the refrigerant outlet of the heat exchange element 3 is connected to the hot water user end 4 through a pipeline.

[0024] Preferably, a cooling water return bypass pipe c is provided between the cooling water return main pipe a and the cooling water return main pipe 2 b, a valve body d is provided on the cooling water return bypass pipe c, a temperature sensor g is provided at the refrigerant outlet of the heat exchange element 3, the valve body d and the temperature sensor g are both electrically connected to the control system, and the valve body d and the temperature sensor g are controlled in linkage, a valve body 2 e is provided at the water outlet of the cooling water return main pipe a, and a valve body 3 f is provided at the water inlet of the cooling water return main pipe 2 b.

[0025] Further preferably, a desalted water tank 7 is included, and the refrigerant inlet of the heat exchange element 3 is connected to the water outlet of the desalted water tank 7 through a circulation pump group 2 6 and a pipeline, and the water inlet of the desalted water tank 7 is connected to industrial water.

[0026] Further preferably, the heat exchange element 3 includes an evaporator 3-1 and a condenser 3-2, the cooling water outlet of the water-cooled air compressor 1 is connected to the shell-side inlet of the evaporator 3-1 through a cooling water return pipe a, the shell-side outlet of the evaporator 3-1 is connected to the return end of the cooling tower 2 through a cooling water return pipe b, the refrigerant inlet of the condenser 3-2 is connected to the outlet of the desalted water tank 7 through a circulating pump group 2 6 and a pipeline, and the refrigerant outlet of the condenser 3-2 is connected to the hot water user end 4 through a pipeline.

[0027] Further preferably, the circulating pump group 1 5 and the circulating pump group 2 6 each include at least two circulating pumps arranged in parallel.

[0028] Working principle of the waste heat recovery system for a water-cooled air compressor in Example 1:

[0029] Under normal working conditions, valve body 1d is closed, valve body 2e and valve body 3f are normally open, and the cooling water discharged from the water-cooled air compressor 1 enters the shell side (heat medium cavity) of the evaporator 3-1 through the cooling water return pipe 1a. At the same time, the low-temperature industrial water is filtered by the desalted water tank 7 and then pumped into the condenser 3-2 through the circulating pump group 26. The working medium absorbs the heat of the high-temperature cooling water in the evaporator 3-1 and evaporates. The compressor inside the evaporator 3-1 compresses it into high-temperature and high-pressure superheated steam, and then enters the condenser 3-2 to produce hot water. The cooling water after cooling in the shell side of the evaporator 3-1 enters the cooling tower 2 through the cooling water return pipe 2b for cooling and cooling to form low-temperature cooling water. The low-temperature cooling water formed in the cooling tower is pumped into the water-cooled air compressor 1 through the cooling water inlet pipe h and the circulating pump group 5 for circulation. The hot water formed in the condenser 3-2 flows into the hot water user end 4 through the pipeline for use.

[0030] Example 2

[0031] like Figure 2 As shown, a waste heat recovery system for a water-cooled air compressor is different from the waste heat recovery system for a water-cooled air compressor in Example 1 in that: the heat exchange element 3 is a coil heat exchanger, and the water inlet end of the coil 3-3 inside the heat exchange element 3 is connected to the water outlet of the desalted water tank 7 through a circulating pump group 2 6 and a pipeline, and the water outlet end of the coil 3-3 inside the heat exchange element 3 is connected to the hot water user end 4 through a pipeline.

[0032] Working principle of the waste heat recovery system for a water-cooled air compressor in Example 2:

[0033] Under normal operating conditions, valve body 1d is closed, valve body 2e and valve body 3f are normally open, and the cooling water discharged from the water-cooled air compressor 1 enters the heat medium cavity of the heat exchange element 3 through the cooling water return pipe 1a. At the same time, the low-temperature industrial water is filtered by the desalted water tank 7 and then pumped into the coil 3-3 of the heat exchange element 3 through the circulating pump group 26. The high-temperature cooling water flowing through the heat medium cavity exchanges heat with the low-temperature water flowing through the coil 3-3. Then, the cooling water after the temperature is reduced in the heat medium cavity enters the cooling tower 2 through the cooling water return pipe 2b to be cooled and cooled to form low-temperature cooling water. The low-temperature cooling water in the cooling tower is pumped into the water-cooled air compressor 1 through the cooling water inlet pipe h and the circulating pump group 5 for circulation. The hot water formed after the temperature is increased in the coil 3-3 of the heat exchange element 3 flows into the hot water user end 4 through the pipeline for use.

[0034] When the hot water user end 4 has strict requirements for the required hot water temperature, the temperature sensor g feeds back the temperature signal to the control system in real time. When the temperature of the hot water discharged from the heat exchange element 3 is too high, the control system sends a command to the valve body 1d to increase the opening degree, so as to reduce the high-temperature cooling water flow rate from the cooling water return main pipe 1a entering the heat exchange element 3, so that part of the water in the cooling water return main pipe 1a enters the cooling water return main pipe 2b through the cooling water return bypass pipe c. On the contrary, when the temperature of the hot water discharged from the heat exchange element 3 is too low, the control system sends a command to the valve body 1d to reduce the opening degree, so as to increase the high-temperature cooling water flow rate from the cooling water return main pipe 1a entering the heat exchange element 3, so as to achieve the purpose of real-time regulation of the temperature of the hot water discharged from the heat exchange element 3; when the heat exchange element fails, the valve body 1d can be fully opened, and the valve bodies 2e and 3f can be closed, so that the cooling water can circulate normally in the water-cooled compressor to ensure the normal operation of the water-cooled compressor.

[0035] The waste heat recovery system for a water-cooled air compressor of the utility model achieves the effect of lowering the temperature of the cooling water and raising the temperature of the industrial water by exchanging heat between the high-temperature cooling water from the water-cooled air compressor and the low-temperature industrial water inside the heat exchange element, so that the temperature of the cooling water returning to the cooling tower will not be too high, thereby effectively reducing the heat discharged from the cooling tower to the atmosphere, reducing or eliminating the thermal radiation pollution to the atmosphere, and reducing the burden on the cooling tower. At the same time, the industrial water with increased temperature is transported to the hot water user end for use, so that the heat in the cooling water can be effectively recovered and utilized, effectively reducing the waste of heat energy, and meeting the requirements of energy conservation and emission reduction; the overall structural design is simple, the application implementation feasibility is high, and the practicability is strong.

[0036] Among them, the hot water in the hot water user end can be used as bathroom water, heating heat medium, and can also be used to preheat the water for steam boilers, thereby reducing the consumption of energy such as natural gas and coal, and meeting energy-saving and environmental protection requirements.

[0037] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A waste heat recovery system for a water-cooled air compressor, characterized in that: The invention comprises a water-cooled air compressor (1), a cooling tower (2), a heat exchange element (3), a hot water user end (4), a circulating pump group 1 (5) and a circulating pump group 2 (6), wherein the cooling water outlet of the water-cooled air compressor (1) is connected to the heat medium inlet of the heat exchange element (3) through a cooling water return pipe 1 (a), the heat medium outlet of the heat exchange element (3) is connected to the return end of the cooling tower (2) through a cooling water return pipe 2 (b), and the water outlet end of the cooling tower (2) is connected to the water-cooled air compressor (1) through a cooling water inlet pipe (h). The cooling water inlet of the air compressor (1) is connected, and a circulating pump group (5) is provided on the cooling water inlet main pipe (h). The refrigerant inlet of the heat exchange element (3) is connected to industrial water through a circulating pump group (6) and a pipeline, and the refrigerant outlet of the heat exchange element (3) is connected to a hot water user end (4) through a pipeline; it also includes a desalted water tank (7), the refrigerant inlet of the heat exchange element (3) is connected to the water outlet of the desalted water tank (7) through a circulating pump group (6) and a pipeline, and the water inlet of the desalted water tank (7) is connected to industrial water.

2. The waste heat recovery system for a water-cooled air compressor according to claim 1, characterized in that: A cooling water return bypass pipe (c) is provided between the cooling water return main pipe 1 (a) and the cooling water return main pipe 2 (b), a valve body 1 (d) is provided on the cooling water return bypass pipe (c), a temperature sensor (g) is provided at the refrigerant outlet of the heat exchange element (3), the valve body 1 (d) and the temperature sensor (g) are both electrically connected to the control system, and the valve body 1 (d) and the temperature sensor (g) are controlled in linkage, the outlet end of the cooling water return main pipe 1 (a) is provided with a valve body 2 (e), and the inlet end of the cooling water return main pipe 2 (b) is provided with a valve body 3 (f).

3. The waste heat recovery system for a water-cooled air compressor according to claim 2, characterized in that: The heat exchange element (3) includes an evaporator (3-1) and a condenser (3-2); the cooling water outlet of the water-cooled air compressor (1) is connected to the shell-side inlet of the evaporator (3-1) through a cooling water return pipe 1 (a); the shell-side outlet of the evaporator (3-1) is connected to the return water end of the cooling tower (2) through a cooling water return pipe 2 (b); the refrigerant inlet of the condenser (3-2) is connected to the water outlet of the desalted water tank (7) through a circulating pump group 2 (6) and a pipeline; and the refrigerant outlet of the condenser (3-2) is connected to the hot water user end (4) through a pipeline.

4. The waste heat recovery system for a water-cooled air compressor according to claim 2, characterized in that: The heat exchange element (3) is a coil heat exchanger, the water inlet end of the coil (3-3) inside the heat exchange element (3) is connected to the water outlet of the desalted water tank (7) through a circulation pump group 2 (6) and a pipeline, and the water outlet end of the coil (3-3) inside the heat exchange element (3) is connected to the hot water user end (4) through a pipeline.

5. The waste heat recovery system for a water-cooled air compressor according to claim 3 or 4, characterized in that: The circulating pump group 1 (5) and the circulating pump group 2 (6) each include at least two circulating pumps arranged in parallel.

Images