Waste heat recovery system for waste incineration power plant and air compressor

Abstract

According to the waste heat recovery system of the waste incineration power plant and the air compressor, a first control valve of the system is used for controlling the flowing direction of oil in an oil gas barrel of the air compressor, and a second control valve of the system is used for controlling the flowing direction of oil at a heat source end outlet of a heat generation unit; a cold source end of the heat generation unit is sequentially connected with a heat source end of the first-stage heat exchange unit, a heat source end of the second-stage heat exchange unit and a heat source end of the third-stage heat exchange unit in parallel, a heat source end outlet of the first-stage heat exchange unit is further connected with a heat source end inlet of the second-stage heat exchange unit, and a heat source end outlet of the second-stage heat exchange unit is further connected with a heat source end inlet of the third-stage heat exchange unit. Due to the fact that cold sources used for heating of all stages of heat exchange units are different, waste heat of the air compressor can be recycled in a graded mode, the heat exchange units are connected in parallel and in series, the flow of all branches can be controlled according to the temperature of the cold source end of the heat generation unit, it is guaranteed that the low-temperature heat exchange unit is located at the last stage of a heat exchange pipeline, and the waste heat utilization efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat recovery, and in particular to a waste heat recovery system for a garbage incineration power plant or an air compressor. Background Art

[0002] Compressed air is a widely used power carrier in the manufacturing industry. It is often used for cooling and purging, material atomization, valve driving and instrument protection in waste incineration power plants. The main equipment of the compressed air system of general waste incineration projects includes micro-oil screw air compressors, refrigerated dryers, micro-heat regeneration adsorption dryers, etc. The air compressor is the preparation equipment for compressed air and the main power-consuming equipment in the compressed air system. The power consumption accounts for about 6% of the power consumption of the waste incineration power plant. It is an important process production equipment in the whole plant.

[0003] During the loading process of the air compressor, the air is compressed in a nearly adiabatic process. The heat generated by the compression must be absorbed by the lubricating oil. Generally, the high-temperature lubricating oil is cooled indirectly by air cooling or water cooling. In this process, the heat generated by the compression is directly discharged into the atmosphere, causing serious energy waste. The heat loss generated during the operation of the air compressor is as high as 85%, which includes motor heat loss, heat radiation and lubricating oil heat dissipation loss. In this regard, how to reasonably utilize the waste heat of the air compressor to reduce energy waste is an urgent problem to be solved. Summary of the invention

[0004] In this regard, the present application provides a waste heat recovery system for a waste incineration power plant and an air compressor, which can reasonably utilize the waste heat of the air compressor and reduce the problem of energy waste.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] The first aspect of the present application discloses a waste heat recovery system for an air compressor, comprising: a first control valve, a second control valve, a heat generating unit, a primary heat exchange unit, a secondary heat exchange unit and a tertiary heat exchange unit;

[0007] The first control valve is used to control the flow direction of the oil in the oil and gas barrel of the air compressor, and the flow direction of the oil in the oil and gas barrel includes a first flow direction and a second flow direction. The first flow direction is that the oil in the oil and gas barrel flows to the oil cooler of the air compressor, and the second flow direction is that the oil in the oil and gas barrel flows to the heat source end inlet of the heat generating unit;

[0008] The second control valve is used to control the flow direction of the oil at the heat source end outlet of the heat generating unit, and the flow direction of the oil at the heat source end outlet of the heat generating unit includes a third flow direction and a fourth flow direction, the third flow direction is that the oil at the heat source end outlet of the heat generating unit flows to the oil cooler, and the fourth flow direction is that the oil at the heat source end outlet of the heat generating unit flows to the oil filter of the air compressor;

[0009] The cold source end of the heat generating unit is connected in parallel with the heat source end of the primary heat exchange unit, the heat source end of the secondary heat exchange unit and the heat source end of the tertiary heat exchange unit in sequence, the heat source end outlet of the primary heat exchange unit is also connected to the heat source end inlet of the secondary heat exchange unit, and the heat source end outlet of the secondary heat exchange unit is also connected to the heat source end inlet of the tertiary heat exchange unit;

[0010] The primary heat exchange unit is used for heating heating water, the diode heat exchange unit is used for heating desalted water, and the tertiary heat exchange unit is used for heating domestic water.

[0011] Optionally, in the above-mentioned waste heat recovery system of the air compressor, the heat generating unit comprises: a first heat generating unit and a second heat generating unit;

[0012] The heat source end inlet of the first heat generating unit serves as the heat source end inlet of the heat generating unit, the heat source end outlet of the first heat generating unit is connected to the heat source end inlet of the second heat generating unit, and the heat source end outlet of the second heat generating unit serves as the heat source end outlet of the heat generating unit;

[0013] The cold source end outlet of the first heat generating unit is connected to the cold source end outlet of the second heat generating unit, and the connection points are respectively connected to the heat source end inlet of the first-stage heat exchange unit, the heat source end inlet of the second-stage heat exchange unit, and the heat source end inlet of the tertiary heat exchange unit;

[0014] The cold source end inlet of the first heat generating unit is connected to the cold source end inlet of the second heat generating unit, and the connection points are respectively connected to the heat source end outlet of the first-stage heat exchange unit, the heat source end outlet of the second-stage heat exchange unit and the heat source end outlet of the tertiary heat exchange unit.

[0015] Optionally, in the above-mentioned waste heat recovery system of the air compressor, the primary heat exchange unit includes: a first heat exchanger, a first stop valve, a second stop valve and a third stop valve;

[0016] One end of the first stop valve serves as the heat source inlet of the primary heat exchange unit, the other end of the first stop valve is connected to the heat source inlet of the first heat exchanger, and the heat source outlet of the first heat exchanger is respectively connected to one end of the second stop valve and one end of the third stop valve;

[0017] The other end of the second stop valve serves as a first outlet of the heat source end of the primary heat exchange unit and is connected to an inlet of the cold source end of the heat generating unit;

[0018] The other end of the third stop valve serves as a second outlet of the heat source end of the primary heat exchange unit and is connected to an inlet of the heat source end of the secondary heat exchange unit.

[0019] Optionally, in the above-mentioned waste heat recovery system of the air compressor, the secondary heat exchange unit includes: a second heat exchanger, a fourth stop valve, a fifth stop valve and a sixth stop valve;

[0020] One end of the fourth stop valve serves as the heat source inlet of the secondary heat exchange unit, the other end of the fourth stop valve is connected to the heat source inlet of the second heat exchanger, and the heat source outlet of the second heat exchanger is respectively connected to one end of the fifth stop valve and one end of the sixth stop valve;

[0021] The other end of the fifth stop valve serves as a first outlet of the heat source end of the secondary heat exchange unit, connected to an inlet of the cold source end of the heat generating unit;

[0022] The other end of the sixth stop valve serves as a second outlet of the heat source end of the secondary heat exchange unit and is connected to an inlet of the heat source end of the tertiary heat exchange unit.

[0023] Optionally, in the above-mentioned waste heat recovery system of the air compressor, the three-stage heat exchange unit includes: a third heat exchanger, a seventh stop valve and an eighth stop valve;

[0024] One end of the seventh stop valve serves as the heat source inlet of the three-stage heat exchange unit, and the other end of the seventh stop valve is connected to the heat source inlet of the third heat exchanger. The heat source outlet of the third heat exchanger is connected to one end of the eighth stop valve, and the other end of the eighth stop valve serves as the heat source outlet of the three-stage heat exchange unit.

[0025] Optionally, in the above-mentioned waste heat recovery system of the air compressor, it further includes: an energy storage unit, used to store the heat energy of the heat generating unit;

[0026] And / or, a water replenishment unit, used to replenish the circulating water at the cold source end of the heat generating unit.

[0027] Optionally, in the above-mentioned waste heat recovery system of the air compressor, the energy storage unit comprises: an energy storage device, a ninth stop valve, a tenth stop valve and an eleventh stop valve;

[0028] One end of the ninth stop valve is connected to the cold source end outlet of the heat generating unit; the other end of the ninth stop valve is connected to the energy storage inlet of the energy storage device, and the energy storage outlet of the energy storage device is respectively connected to one end of the tenth stop valve and one end of the eleventh stop valve;

[0029] The other end of the tenth stop valve is connected to the cold source end inlet of the heat generating unit, and the other end of the eleventh stop valve is connected to the cold source end outlet of the heat generating unit;

[0030] The water replenishment unit comprises: a water replenishment solenoid valve, one end of which is connected to a water replenishment source, and the other end of which is connected to an inlet of a cold source end of the heat generating unit.

[0031] Optionally, in the above-mentioned waste heat recovery system of the air compressor, it further includes: a first booster pump, which is arranged in a pipeline connecting the energy storage outlet of the energy storage device and the cold source end outlet of the heat generating unit;

[0032] And / or, a second booster pump, wherein the second booster pump is arranged in the pipeline where the cold source end inlet of the heat generating unit is located.

[0033] Optionally, in the above-mentioned waste heat recovery system of the air compressor, when the oil temperature of the first control valve is lower than a first preset temperature, the first control valve is in the first flow direction;

[0034] When the oil temperature at the first control valve is greater than the first preset temperature, the first control valve is in the second flow direction;

[0035] When the oil temperature at the outlet of the heat source end of the heat generating unit is greater than the second preset temperature, the second control valve is in the third flow direction;

[0036] When the oil temperature at the outlet of the heat source end of the heat generating unit is lower than the second preset temperature, the second control valve is in the fourth flow direction;

[0037] Wherein, the first preset temperature is less than or equal to the second preset temperature.

[0038] The second aspect of the present application discloses a waste incineration power plant, comprising: N air compressors, where N is a positive integer; each of the air compressors is provided with a waste heat recovery system of the air compressor as disclosed in any one of the first aspects;

[0039] When the first control valve in the waste heat recovery system of the air compressor is in the second flow direction, the second booster pump in the waste heat recovery system of the air compressor is adjusted so that the flow at the cold source end of the heat generating unit in the waste heat recovery system of the air compressor reaches the rated flow.

[0040] The present invention provides a waste heat recovery system for an air compressor, comprising: a first control valve, a second control valve, a heat generating unit, a primary heat exchange unit, a secondary heat exchange unit and a tertiary heat exchange unit; the first control valve is used to control the flow direction of oil in an oil and gas barrel of the air compressor, the flow direction of the oil in the oil and gas barrel includes a first flow direction and a second flow direction, the first flow direction is that the oil in the oil and gas barrel flows to an oil cooler of the air compressor, and the second flow direction is that the oil in the oil and gas barrel flows to an inlet of a heat source end of the heat generating unit; the second control valve is used to control the flow direction of oil at an outlet of a heat source end of the heat generating unit, the flow direction of oil at an outlet of a heat source end of the heat generating unit includes a third flow direction and a fourth flow direction, the third flow direction is that the oil at an outlet of a heat source end of the heat generating unit flows to an oil cooler, and the fourth ... The oil at the outlet flows to the oil filter of the air compressor; the cold source end of the heat generating unit is connected in parallel with the heat source end of the first-stage heat exchange unit, the heat source end of the second-stage heat exchange unit and the heat source end of the tertiary heat exchange unit in sequence, the heat source end outlet of the first-stage heat exchange unit is also connected to the heat source end inlet of the second-stage heat exchange unit, and the heat source end outlet of the second-stage heat exchange unit is also connected to the heat source end inlet of the tertiary heat exchange unit; the first-stage heat exchange unit is used to heat heating water, the diode heat exchange unit is used to heat desalted water, and the tertiary heat exchange unit is used to heat domestic water. The waste heat of the air compressor can be recovered in stages, and the heat exchange units at each stage are connected in parallel + series. The flow rate of each branch can be controlled according to the temperature of the cold source end of the heat generating unit to ensure that the low-temperature heat exchange unit is located at the last stage of the heat exchange pipeline, thereby improving the utilization efficiency of waste heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0042] Figure 1 A schematic diagram of a structure for utilizing waste heat from an air compressor provided in this application;

[0043] Figures 2 to 4 Schematic diagram of the structures of waste heat recovery systems for three air compressors provided in the embodiments of the present application. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] First of all, it should be noted that Figure 1 Taking the water-cooled micro-oil screw air compressor as an example, its working process includes: air intake, compression, and exhaust. The heat generated needs to be carried by lubricating oil and exchanged with cooling water. The working principle of the air compressor is: air is sucked in through the pre-filter of the air compressor, and a pair of parallel and meshing yin and yang rotors in the main engine are driven by the motor to squeeze the air between the yin and yang rotors. This cycle reduces the volume of the air and increases the pressure, and it is discharged along the axis of the rotor to the oil and gas barrel. During the compression process, lubricating oil is continuously sprayed in. On the one hand, it produces an oil film to prevent air backflow, and on the other hand, it takes away the heat generated by air compression and reduces the temperature of the screw and the main engine. The oil-gas mixture generated during the compression process enters the oil-gas barrel through a one-way valve. Most of the oil falls to the bottom of the barrel due to centrifugal force and gravity, and a small amount of suspended oil particles mix with air to form oil mist, which is separated for the second time by the oil-gas separator. The separated compressed air enters the refrigeration dryer through the aftercooler to produce process air, and the rest enters the adsorption dryer to produce instrument air; the separated lubricating oil enters the oil cooler, and the cooled lubricating oil is filtered by the oil filter and sprayed into the air compressor host to complete the periodic cycle.

[0046] The embodiment of the present application provides a waste heat recovery system for a waste incineration power plant and an air compressor, which can reasonably utilize the waste heat of the air compressor and reduce the problem of energy waste.

[0047] Among them, the air compressor in this application is Figures 1 to 4 The air compressor host in.

[0048] See also Figure 2 and Figure 3 The waste heat recovery system of the air compressor mainly includes: a first control valve 101, a second control valve 102, a heat generating unit 103, a primary heat exchange unit 104, a secondary heat exchange unit 105 and a tertiary heat exchange unit 106;

[0049] The first control valve 101 is used to control the flow direction of the oil in the oil and gas barrel of the air compressor. The flow direction of the oil in the oil and gas barrel includes a first flow direction and a second flow direction. The first flow direction is that the oil in the oil and gas barrel flows to the oil cooler of the air compressor, and the second flow direction is that the oil in the oil and gas barrel flows to the heat source end inlet of the heat generating unit 103;

[0050] In practical applications, the first control valve 101 can be a temperature control valve that can control the flow direction and flow rate according to the temperature of the oil flowing through it. The basic principle is: by controlling the inlet flow rate of the heat exchanger, air conditioning unit or other heat and cold equipment, the primary hot (cold) medium, the outlet temperature of the control equipment can be controlled. When the load changes, the flow rate is adjusted by changing the valve opening to eliminate the impact of load fluctuations and restore the temperature to the set value.

[0051] Specifically, when the oil temperature of the first control valve 101 is lower than the first preset temperature, the first control valve 101 is in the first flow direction; when the oil temperature at the first control valve 101 is greater than the first preset temperature, the first control valve 101 is in the second flow direction.

[0052] In practice, the specific value of the first preset temperature can be obtained based on the stable operation of the system and economic considerations, such as 60°C; of course, it is not limited to this, and can also be determined according to the application environment and user needs. This application does not limit it and it is within the scope of protection of this application.

[0053] It should be noted that when the oil temperature of the first control valve 101 is lower than the first preset temperature, it can be known that the oil temperature in the oil and gas barrel of the air compressor is low, the waste heat energy of the air compressor is low, and the economic benefit of enabling waste heat recovery is poor and affects the stable operation of the system. The first control valve 101 can be controlled to be in the first flow direction, and the original oil circuit of the air compressor is used for cooling to ensure the stable operation of the air compressor. When the oil temperature at the first control valve 101 is greater than the first preset temperature, it can be known that the oil temperature in the oil and gas barrel of the air compressor is high, the waste heat energy of the air compressor is high, and the economic benefit of enabling waste heat recovery is good and conducive to the stable operation of the system. The first control valve 101 can be controlled to be in the second flow direction, and the heat generation unit 103, the first heat exchange unit 104, the second heat exchange unit 105 and the third heat exchange unit 106 are used for waste heat recovery.

[0054] The second control valve 102 is used to control the oil flow direction of the heat source end outlet of the heat generating unit 103. The oil flow direction of the heat source end outlet of the heat generating unit 103 includes a third flow direction and a fourth flow direction. The third flow direction is that the oil at the heat source end outlet of the heat generating unit 103 flows to the oil cooler, and the fourth flow direction is that the oil at the heat source end outlet of the heat generating unit 103 flows to the oil filter of the air compressor.

[0055] In actual applications, the second control valve 102 can be a three-way temperature-controlled regulating proportional valve, the first end of the three-way temperature-controlled regulating proportional valve is connected to the heat source end outlet of the heat generating unit 103, the second end of the three-way temperature-controlled regulating proportional valve is connected to the inlet of the oil cooler, and the third end of the three-way temperature-controlled regulating proportional valve is connected to the inlet of the oil filter.

[0056] Specifically, when the oil temperature at the outlet of the heat source end of the heat generating unit 103 is greater than the second preset temperature, the second control valve 102 is in the third flow direction; when the oil temperature at the outlet of the heat source end of the heat generating unit 103 is less than the second preset temperature, the second control valve 102 is in the fourth flow direction.

[0057] It should be noted that when the oil temperature at the outlet of the heat source end of the heat generating unit 103 is greater than the second preset temperature, it can be known that the oil temperature after being processed by the heat generating unit 103 is still high and cannot meet the lubrication and cooling requirements of the air compressor, and still needs to be cooled. At this time, the second control valve 102 can be controlled to be in the third flow direction, and the oil cooler in the original oil circuit of the air compressor is used for cooling to ensure the stable operation of the air compressor. When the oil temperature at the outlet of the heat source end of the heat generating unit 103 is less than the second preset temperature, it can be known that the oil temperature after being processed by the heat generating unit 103 is low, which meets the lubrication and cooling requirements of the air compressor. The second control valve 102 can be controlled to be in the fourth flow direction, and the oil filter in the original oil circuit of the air compressor is directly used for filtering.

[0058] In practice, the specific value of the second preset temperature can be determined according to the application environment and user needs, for example, 75° C., which is not limited in this application and is within the protection scope of this application.

[0059] It should also be noted that, in order to ensure stable operation of the air compressor, the first preset temperature is generally less than or equal to the second preset temperature.

[0060] The cold source end of the heat generating unit 103 is connected in parallel with the heat source end of the primary heat exchange unit 104, the heat source end of the secondary heat exchange unit 105, and the heat source end of the tertiary heat exchange unit 106 in sequence, the heat source end outlet of the primary heat exchange unit 104 is also connected to the heat source end inlet of the secondary heat exchange unit 105, and the heat source end outlet of the secondary heat exchange unit 105 is also connected to the heat source end inlet of the tertiary heat exchange unit 106;

[0061] The primary heat exchange unit 104 is used to heat heating water, the secondary heat exchange unit 105 is used to heat desalted water, and the tertiary heat exchange unit 106 is used to heat domestic water.

[0062] like Figure 2 As shown, in some embodiments, the heat generating unit 103 may include: a first heat generating unit 1031 and a second heat generating unit 1032;

[0063] The heat source end inlet of the first heat generating unit 1031 serves as the heat source end inlet of the heat generating unit 103, the heat source end outlet of the first heat generating unit 1031 is connected to the heat source end inlet of the second heat generating unit 1032, and the heat source end outlet of the second heat generating unit 1032 serves as the heat source end outlet of the heat generating unit 103;

[0064] The cold source end outlet of the first heat generating unit 1031 is connected to the cold source end outlet of the second heat generating unit 1032, and the connection points are respectively connected to the heat source end inlet of the primary heat exchange unit 104, the heat source end inlet of the secondary heat exchange unit 105, and the heat source end inlet of the tertiary heat exchange unit 106;

[0065] The cold source end inlet of the first heat generating unit 1031 is connected to the cold source end inlet of the second heat generating unit 1032, and the connection points are respectively connected to the heat source end outlet of the first-stage heat exchange unit 104, the heat source end outlet of the second-stage heat exchange unit 105 and the heat source end outlet of the tertiary heat exchange unit 106.

[0066] In practical applications, the first heat generating unit 1031 and the second heat generating unit 1032 are connected in series to form a heat generating unit 103, which can fully exchange the waste heat of the air compressor, further improving the waste heat recovery rate of the air compressor; and, when a heat generating unit fails, the other heat generating unit can continue to operate to recover the waste heat of the air compressor, further improving the stability of the waste heat recovery system of the air compressor.

[0067] It should be noted that the number of heat generating units in the actual heat generating unit 103 connected in series can also be determined according to the application environment and user needs. This application does not make any specific limitations and all are within the protection scope of this application.

[0068] It should also be noted that the heat generating unit is the key equipment for recovering waste heat from the air compressor. It draws out the lubricating oil from the air compressor, sets up a plate heat exchanger, and configures a heat exchange device with instruments such as temperature and flow control.

[0069] In some embodiments, Figure 2 As shown, the primary heat exchange unit 104 may include: a first heat exchanger 1041, a first stop valve A1, a second stop valve A2 and a third stop valve A3;

[0070] One end of the first stop valve A1 serves as the heat source inlet of the primary heat exchange unit 104, the other end of the first stop valve A1 is connected to the heat source inlet of the first heat exchanger 1041, and the heat source outlet of the first heat exchanger 1041 is respectively connected to one end of the second stop valve A2 and one end of the third stop valve A3; the other end of the second stop valve A2 serves as the first outlet of the heat source of the primary heat exchange unit 104, connected to the cold source inlet of the heat generating unit 103; the other end of the third stop valve A3 serves as the second outlet of the heat source of the primary heat exchange unit 104, connected to the heat source inlet of the secondary heat exchange unit 105.

[0071] In practical applications, by controlling the on-off of the first stop valve A1, the on-off of the connecting pipeline between the heat source end inlet of the first-level heat exchange unit 104 and the cold source end outlet of the heat generating unit 103 can be controlled; by controlling the on-off of the second stop valve A2, the on-off of the connecting pipeline between the heat source end outlet of the first-level heat exchange unit 104 and the cold source end inlet of the heat generating unit 103 can be controlled; by controlling the on-off of the third stop valve A3, the on-off of the connecting pipeline between the heat source end outlet of the first-level heat exchange unit 104 and the heat source end inlet of the second-level heat exchange unit 105 can be controlled.

[0072] It should be noted that since the first heat exchanger 1041 can be used to heat the heating water, the heating water enters the first heat exchanger 1041 from the cold source end inlet of the first heat exchanger 1041 for heat exchange; in specific applications, in order to ensure that the heating water meets the supply standard, a hot water pump can also be added to the cold source end inlet of the first heat exchanger 1041 to increase the pressure of the heating water outlet.

[0073] In some embodiments, Figure 3 As shown, the secondary heat exchange unit 105 includes: a second heat exchanger 1051, a fourth stop valve A4, a fifth stop valve A5 and a sixth stop valve A6;

[0074] One end of the fourth stop valve A4 serves as the heat source inlet of the secondary heat exchange unit 105, the other end of the fourth stop valve A4 is connected to the heat source inlet of the second heat exchanger 1051, and the heat source outlet of the second heat exchanger 1051 is respectively connected to one end of the fifth stop valve A5 and one end of the sixth stop valve A6; the other end of the fifth stop valve A5 serves as the first heat source outlet of the secondary heat exchange unit 105, connected to the cold source inlet of the heat generating unit 103; the other end of the sixth stop valve A6 serves as the second heat source outlet of the secondary heat exchange unit 105, connected to the heat source inlet of the tertiary heat exchange unit 106.

[0075] In actual applications, by controlling the on-off of the fourth stop valve A4, the on-off of the connecting pipeline between the heat source end inlet of the secondary heat exchange unit 105 and the cold source end outlet of the heat generating unit 103 can be controlled; by controlling the on-off of the fifth stop valve A5, the on-off of the connecting pipeline between the heat source end outlet of the secondary heat exchange unit 105 and the cold source end inlet of the heat generating unit 103 can be controlled; by controlling the on-off of the sixth stop valve A6, the on-off of the connecting pipeline between the heat source end outlet of the secondary heat exchange unit 105 and the heat source end inlet of the tertiary heat exchange unit 106 can be controlled.

[0076] It should be noted that, since the second heat exchanger 1051 can be used to heat desalted water, the desalted water enters the second heat exchanger 1051 from the cold source end inlet of the second heat exchanger 1051 for heat exchange.

[0077] In some embodiments, Figure 3 As shown, the three-stage heat exchange unit 106 may include: a third heat exchanger 1061, a seventh stop valve A7 and an eighth stop valve A8;

[0078] One end of the seventh stop valve A7 serves as the heat source inlet of the three-stage heat exchange unit 106, and the other end of the seventh stop valve A7 is connected to the heat source inlet of the third heat exchanger 1061. The heat source outlet of the third heat exchanger 1061 is connected to one end of the eighth stop valve A8, and the other end of the eighth stop valve A8 serves as the heat source outlet of the three-stage heat exchange unit 106.

[0079] In actual applications, by controlling the on-off of the seventh stop valve A7, the on-off of the connecting pipeline between the heat source end inlet of the tertiary heat exchange unit 106 and the cold source end outlet of the heat generating unit 103 can be controlled; by controlling the on-off of the eighth stop valve A8, the on-off of the connecting pipeline between the heat source end outlet of the tertiary heat exchange unit 106 and the cold source end inlet of the heat generating unit 103 can be controlled.

[0080] It should be noted that, since the third heat exchanger 1061 can be used to heat domestic water, the domestic water can enter the third heat exchanger 1061 from the cold source end inlet of the third heat exchanger 1061 for heat exchange.

[0081] In a specific application, the primary heat exchange unit 104 can be activated during the winter heating period and shut down at other times; the secondary heat exchange unit 105 and the tertiary heat exchange unit 106 can operate continuously throughout the year to absorb the waste heat of the air compressor.

[0082] It should be noted that the first heat exchanger 1041, the second heat exchanger 1051 and the third heat exchanger 1061 can adopt plate heat exchangers; of course, it is not limited to this, and can also be determined according to the application environment and user needs. This application does not limit it and they are all within the protection scope of this application.

[0083] It should also be noted that the heat exchange medium of the heat generating unit 103 in the present application can be water, that is, the cold source end of the heat generating unit 103 is circulating water. In order to reduce the scaling risk of the heat exchangers in each stage of the heat exchange unit, desalted water or softened water can be used as circulating water.

[0084] Based on the above, the waste heat recovery system of the air compressor provided in this embodiment includes: a first control valve 101, a second control valve 102, a heat generating unit 103, a primary heat exchange unit 104, a secondary heat exchange unit 105 and a tertiary heat exchange unit 106; the first control valve 101 is used to control the flow direction of oil in the oil and gas barrel of the air compressor, and the oil flow direction of the oil and gas barrel includes a first flow direction and a second flow direction. The first flow direction is that the oil in the oil and gas barrel flows to the oil cooler of the air compressor, and the second flow direction is that the oil in the oil and gas barrel flows to the heat source end inlet of the heat generating unit 103; the second control valve 102 is used to control the flow direction of oil at the heat source end outlet of the heat generating unit 103. The oil flow direction at the heat source end outlet of the heat generating unit 103 includes a third flow direction and a fourth flow direction. The third flow direction is that the oil at the heat source end outlet of the heat generating unit 103 flows to the oil cooler, and the fourth flow direction is that the oil at the heat source end outlet of the heat generating unit 103 flows to the oil cooler, and the fourth flow direction is that the oil at the heat source end outlet of the heat generating unit 103 flows to the oil cooler. The oil at the outlet of the heat source end flows to the oil filter of the air compressor; the cold source end of the heat generating unit 103 is connected in parallel with the heat source end of the first-stage heat exchange unit 104, the heat source end of the second-stage heat exchange unit 105 and the heat source end of the tertiary heat exchange unit 106 in sequence, the heat source end outlet of the first-stage heat exchange unit 104 is also connected to the heat source end inlet of the second-stage heat exchange unit 105, and the heat source end outlet of the second-stage heat exchange unit 105 is also connected to the heat source end inlet of the tertiary heat exchange unit 106; the first-stage heat exchange unit 104 is used to heat heating water, the diode heat exchange unit is used to heat desalted water, and the tertiary heat exchange unit 106 is used to heat domestic water, which can recover the waste heat of the air compressor in stages, and the heat exchange units at each stage are connected in parallel + series, and the flow of each branch can be controlled according to the temperature of the cold source end of the heat generating unit 103, to ensure that the low-temperature heat exchange unit is located at the last stage of the heat exchange pipeline, thereby improving the utilization efficiency of waste heat.

[0085] It is worth noting that the waste heat recovery system of the air compressor provided in the present application does not change the intake, compression, and exhaust processes of the air compressor. It only modifies the oil circuit of the air compressor and adds a waste heat recovery system of the air compressor to the oil circuit of the air compressor. While realizing the waste heat recovery and utilization of the air compressor, it does not affect the normal operation of the air compressor.

[0086] In addition, since the waste heat recovery system of the air compressor is connected to the oil and gas tank, oil cooler and oil filter in the original oil circuit of the air compressor through the first control valve 101 and the second control valve 102, the original oil circuit of the air compressor and the waste heat recovery system can be divided into two independent systems. When the waste heat recovery system is in operation, it will not affect the operation of the oil circuit of the air compressor. The waste heat recovery system can also cooperate with the oil circuit to achieve cooling of the air compressor.

[0087] Optionally, another embodiment of the present application provides a waste heat recovery system for an air compressor, such as Figure 4 As shown, it also includes: an energy storage unit 107, which is used to store the heat energy of the heat generating unit 103;

[0088] And / or, a water replenishment unit 108 is used to replenish the circulating water at the cold source end of the heat generating unit 103.

[0089] In practical applications, such as Figure 4 As shown, the energy storage unit 107 may include: an energy storage device 1071, a ninth stop valve A9, a tenth stop valve A10 and an eleventh stop valve A11;

[0090] One end of the ninth stop valve A9 is connected to the cold source end outlet of the heat generating unit 103, and the other end of the ninth stop valve A9 is connected to the energy storage inlet of the energy storage device 1071, and the energy storage outlet of the energy storage device 1071 is respectively connected to one end of the tenth stop valve A10 and one end of the eleventh stop valve A11; the other end of the tenth stop valve A10 is connected to the cold source end inlet of the heat generating unit 103, and the other end of the eleventh stop valve A11 is connected to the cold source end outlet of the heat generating unit 103.

[0091] It should be noted that by controlling the on-off of the ninth stop valve A9, the on-off of the pipeline connecting the energy storage outlet of the energy storage device 1071 and the cold source end outlet of the heat generating unit 103 can be controlled; by controlling the tenth stop valve A10, the on-off of the pipeline connecting the energy storage outlet of the energy storage device 1071 and the cold source end inlet of the heat generating unit 103 can be controlled; by controlling the on-off of the eleventh stop valve A11, the on-off of the pipeline connecting the energy storage outlet of the energy storage device 1071 and the cold source end outlet of the heat generating unit 103 can be controlled.

[0092] In practical applications, an energy storage unit 107 is set in the waste heat recovery system. When the demand on the heat exchange unit is small, the energy storage unit 107 can be used to absorb heat and store energy, and release heat to the outside when the demand on the heat exchange unit is large, further improving the energy utilization efficiency of the waste heat recovery system.

[0093] like Figure 4 As shown, in some embodiments, the water replenishment unit 108 may include: a water replenishment solenoid valve A12, one end of the water replenishment solenoid valve A12 is connected to a water replenishment source, and the other end of the water replenishment solenoid valve A12 is connected to the cold source end inlet of the heat generating unit 103.

[0094] In practical applications, the on-off of the water replenishment solenoid valve A12 can be controlled to control the on-off of the connecting pipeline between the replenishment water source and the cold source end inlet of the heat generating unit 103, so as to control whether to replenish desalted water to the waste heat recovery system. This solves the problem that the amount of desalted water replenishment in the waste heat recovery system is too small to absorb all the waste heat of the air compressor.

[0095] Optionally, another embodiment of the present application provides a waste heat recovery system for an air compressor, such as Figure 4As shown, it also includes: a first pressurizing pump P1, the first pressurizing pump P1 is arranged in a pipeline connecting the energy storage outlet of the energy storage device 1071 and the cold source end outlet of the heat generating unit 103;

[0096] And / or, a second booster pump P2, the second booster pump P2 is arranged in the pipeline where the cold source end inlet of the heat generating unit 103 is located.

[0097] Taking the heat generating unit 103 including the first heat generating unit 1031 and the second heat generating unit 1032 as an example, the first booster pump P1 is specifically arranged at the energy storage outlet of the energy storage device 1071, and is connected to the pipeline of the cold source end outlet of the first heat generating unit 1031 and the second heat generating unit 1032; the second booster pump P2 is arranged in the pipeline where the cold source end inlet of the first heat generating unit 1031 and the second heat generating unit 1032 is located.

[0098] In practical applications, a first booster pump P1 is added to the pipeline connecting the energy storage outlet of the energy storage device 1071 and the cold source end outlet of the heat generating unit 103, which can increase the pressure of the water discharged from the energy storage unit 107 to the heat generating unit 103, increase the ability of the energy storage unit 107 to participate in the heat cycle, and further improve the energy utilization efficiency of the waste heat recovery system of the air compressor.

[0099] However, adding a second booster pump P2 to the pipeline at the cold source end inlet of the heat generating unit 103 can increase the water circulation pressure among the primary heat exchange unit 104, the secondary heat exchange unit 105, the tertiary heat exchange unit 106 and the heat generating unit 103, thereby improving the heat exchange capacity between the heat generating unit 103 and the primary heat exchange unit 104, the secondary heat exchange unit 105 and the tertiary heat exchange unit 106, and further improving the energy utilization efficiency of the waste heat recovery system of the air compressor.

[0100] It is worth noting that compared with the existing method of using a simple heat exchanger to directly use the waste heat of the air compressor to heat domestic water, the waste heat recovery system of the air compressor provided in this application can be used not only to heat domestic water, but also to heat heating water and desalted water, avoiding the problem of discontinuous heat absorption of domestic water.

[0101] In addition, compared with the existing multi-stage compression using an air compressor, adding a heat exchanger at each stage for direct use, although it is possible to increase the temperature of the gas after the first-stage compression of the air compressor by combining with a heat pump to avoid the problem of ineffective utilization of waste heat recovery due to the low temperature of the compressed gas, the air compressors used in waste incineration plants are mostly single-unit or two-stage compressor units, and the cost of using the above method is relatively high; moreover, the existing method cannot switch the application of the heat exchange units at each stage, and cannot reasonably allocate the waste heat recovery, affecting the waste heat recovery efficiency; finally, the existing method does not have an energy storage unit 107, and cannot store excess heat energy.

[0102] Optionally, based on the above, another embodiment of the present application further provides a waste incineration power plant, comprising: N air compressors, N being a positive integer; each air compressor being provided with a waste heat recovery system of the air compressor as described in any of the above embodiments;

[0103] When the first control valve 101 in the waste heat recovery system of the air compressor is in the second flow direction, the second booster pump P2 in the waste heat recovery system of the air compressor is adjusted to make the flow at the cold source end of the heat generating unit 103 in the waste heat recovery system of the air compressor reach the rated flow.

[0104] In actual applications, the first control valve 101 in the waste heat recovery system of the air compressor is in the second flow direction, which means that the waste heat recovery system of the air compressor is turned on. In order to ensure that the waste heat recovery system is in the optimal waste heat recovery state, the second booster pump P2 in the waste heat recovery system of the air compressor can be adjusted according to the oil temperature of the first control valve 101 and the oil temperature at the heat source end outlet of the heat generating unit 103, so that the outlet temperature of the cold source end of the waste heat recovery system of the air compressor reaches the third preset temperature, thereby making the flow rate at the cold source end of the waste heat recovery system of the air compressor reach the rated flow rate.

[0105] Among them, the outlet temperature of the cold source end in the waste heat recovery system of the air compressor reaches the third preset temperature, which is the temperature corresponding to the highest waste heat recovery utilization rate and maximum benefit of the waste heat recovery system; exemplarily, the third preset temperature can be 65°C, but of course it is not limited to this, and can also be determined according to the application environment and user needs, all within the protection scope of this application.

[0106] It should be noted that in practice, an independent controller can be configured for each air compressor in a waste incineration power plant, or all air compressors in the power plant can be controlled by one controller; it can be determined based on the application environment and user needs, and is within the protection scope of this application.

[0107] Specifically, the controller can be used to independently set control parameters through the human-machine interface of the controller to control the waste heat recovery system of each air compressor in the waste incineration power plant. Furthermore, the control of the waste heat recovery system of the air compressor includes but is not limited to the following four stages of control, and also includes the control of each valve and each water pump of the waste heat recovery system of the air compressor.

[0108] In practical applications, the operation process of the waste heat recovery system of the air compressor in the waste incineration power plant can be as follows, which is mainly divided into four stages:

[0109] Preparation stage: It is detected that the oil temperature of the first control valve 101 is lower than the first preset temperature, and the first control valve 101 is in the first flow direction, ensuring that the air compressor operates at a suitable temperature.

[0110] Start-up phase: it is detected that the oil temperature of the first control valve 101 is higher than the first preset temperature, the first control valve 101 is in the second flow direction, the oil in the oil and gas tank of the air compressor flows to the heat source end inlet of the heat generating unit 103, and the waste heat recovery system is turned on.

[0111] Operation stage: the first control valve 101 in the waste heat recovery system of the air compressor is in the second flow direction, that is, after the waste heat recovery system is turned on, the second booster pump P2 in the waste heat recovery system is adjusted to make the flow at the cold source end of the heat generating unit 103 in the waste heat recovery system reach the rated flow.

[0112] Unit protection stage: when the oil temperature at the outlet of the heat source end of the heat generating unit 103 is greater than the second preset temperature, the second control valve 102 is in the third flow direction, and the oil at the outlet of the heat source end of the heat generating unit 103 flows to the oil cooler; when the oil temperature at the outlet of the heat source end of the heat generating unit 103 is less than the second preset temperature, the second control valve 102 is in the fourth flow direction, and the oil at the outlet of the heat source end of the heat generating unit 103 flows to the oil filter of the air compressor.

[0113] It should be noted that when the oil temperature at the outlet of the heat source end of the heat generating unit 103 is greater than the second preset temperature, it means that the waste heat recovery system cannot completely absorb the waste heat of the air compressor, and the temperature of the lubricating oil treated by the waste heat recovery system is still too high. In order to ensure the reliable operation of the air compressor, the second control valve 102 can be controlled to be in the third flow direction, and the lubricating oil can be cooled by the oil cooler of the air compressor to further reduce the temperature of the lubricating oil of the air compressor.

[0114] Specifically, in practice, if the load of the air compressor increases, causing the circulating return water temperature at the cold source end to overheat and the oil temperature at the heat source end outlet of the heat generating unit 103 is greater than the second preset temperature, the second control valve 102 can be controlled to be in the fourth flow direction.

[0115] It should also be noted that after the waste heat recovery system is started, the temperature of the lubricating oil of the air compressor gradually increases. After exceeding the first preset temperature, the circulating flow rate at the cold source end of the heat generating unit 103 in the waste heat recovery system can be gradually increased to reduce the temperature of the lubricating oil. During the operation of the waste heat recovery system, the temperature of the lubricating oil continues to increase, and the circulating flow rate at the cold source end of the heat generating unit 103 continues to be adjusted until the temperature of the lubricating oil reaches the third preset temperature, at which time the circulating water flow rate reaches the rated flow rate.

[0116] Exemplarily, the process of determining the rated flow rate is as follows: Assuming that the waste heat recovery power of the air compressor is 70% of the input power, taking a 300kW unit as an example: 300×70%=210kw; the cooling water inlet temperature is 40°C, the outlet temperature is 50°C, and the flow rate should be Q=210kw×3600 / ((50-40)×4.187) / 1000=18t / h.

[0117] Based on the above principles, each air compressor in the waste incineration power plant provided in this embodiment can adjust the second booster pump P2 in the waste heat recovery system of the air compressor when the first control valve 101 in the waste heat recovery system of the air compressor is in the second flow direction, so that the flow rate at the cold source end of the heat generating unit 103 in the waste heat recovery system of the air compressor reaches the rated flow rate, which can ensure the stable operation of each air compressor and improve the overall waste heat recovery efficiency and operation stability of the waste incineration power plant.

[0118] The features recorded in the various embodiments in this specification can be replaced or combined with each other, and the same and similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The system and system embodiments described above are only schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work. Professionals can also further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this article can be implemented in electronic hardware, computer software or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to the function. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0119] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0120] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

Claims

1. A waste heat recovery system for an air compressor, characterized in that: include: A first control valve, a second control valve, a heat generating unit, a primary heat exchanging unit, a secondary heat exchanging unit and a tertiary heat exchanging unit; The first control valve is used to control the flow direction of the oil in the oil and gas barrel of the air compressor, and the flow direction of the oil in the oil and gas barrel includes a first flow direction and a second flow direction. The first flow direction is that the oil in the oil and gas barrel flows to the oil cooler of the air compressor, and the second flow direction is that the oil in the oil and gas barrel flows to the heat source end inlet of the heat generating unit; The second control valve is used to control the flow direction of the oil at the heat source end outlet of the heat generating unit, and the flow direction of the oil at the heat source end outlet of the heat generating unit includes a third flow direction and a fourth flow direction, the third flow direction is that the oil at the heat source end outlet of the heat generating unit flows to the oil cooler, and the fourth flow direction is that the oil at the heat source end outlet of the heat generating unit flows to the oil filter of the air compressor; The cold source end of the heat generating unit is connected in parallel with the heat source end of the primary heat exchange unit, the heat source end of the secondary heat exchange unit and the heat source end of the tertiary heat exchange unit in sequence, the heat source end outlet of the primary heat exchange unit is also connected to the heat source end inlet of the secondary heat exchange unit, and the heat source end outlet of the secondary heat exchange unit is also connected to the heat source end inlet of the tertiary heat exchange unit; The primary heat exchange unit is used for heating heating water, the diode heat exchange unit is used for heating desalted water, and the tertiary heat exchange unit is used for heating domestic water.

2. The waste heat recovery system for an air compressor according to claim 1, characterized in that: The heat generating unit comprises: a first heat generating unit and a second heat generating unit; The heat source end inlet of the first heat generating unit serves as the heat source end inlet of the heat generating unit, the heat source end outlet of the first heat generating unit is connected to the heat source end inlet of the second heat generating unit, and the heat source end outlet of the second heat generating unit serves as the heat source end outlet of the heat generating unit; The cold source end outlet of the first heat generating unit is connected to the cold source end outlet of the second heat generating unit, and the connection points are respectively connected to the heat source end inlet of the first-stage heat exchange unit, the heat source end inlet of the second-stage heat exchange unit, and the heat source end inlet of the tertiary heat exchange unit; The cold source end inlet of the first heat generating unit is connected to the cold source end inlet of the second heat generating unit, and the connection points are respectively connected to the heat source end outlet of the first-stage heat exchange unit, the heat source end outlet of the second-stage heat exchange unit and the heat source end outlet of the tertiary heat exchange unit.

3. The waste heat recovery system for an air compressor according to claim 2, characterized in that: The primary heat exchange unit comprises: a first heat exchanger, a first stop valve, a second stop valve and a third stop valve; One end of the first stop valve serves as the heat source inlet of the primary heat exchange unit, the other end of the first stop valve is connected to the heat source inlet of the first heat exchanger, and the heat source outlet of the first heat exchanger is respectively connected to one end of the second stop valve and one end of the third stop valve; The other end of the second stop valve serves as a first outlet of the heat source end of the primary heat exchange unit and is connected to an inlet of the cold source end of the heat generating unit; The other end of the third stop valve serves as a second outlet of the heat source end of the primary heat exchange unit and is connected to an inlet of the heat source end of the secondary heat exchange unit.

4. The waste heat recovery system for an air compressor according to claim 3, characterized in that: The secondary heat exchange unit comprises: a second heat exchanger, a fourth stop valve, a fifth stop valve and a sixth stop valve; One end of the fourth stop valve serves as the heat source inlet of the secondary heat exchange unit, the other end of the fourth stop valve is connected to the heat source inlet of the second heat exchanger, and the heat source outlet of the second heat exchanger is respectively connected to one end of the fifth stop valve and one end of the sixth stop valve; The other end of the fifth stop valve serves as a first outlet of the heat source end of the secondary heat exchange unit, connected to an inlet of the cold source end of the heat generating unit; The other end of the sixth stop valve serves as a second outlet of the heat source end of the secondary heat exchange unit and is connected to an inlet of the heat source end of the tertiary heat exchange unit.

5. The waste heat recovery system for an air compressor according to claim 3, characterized in that: The three-stage heat exchange unit comprises: a third heat exchanger, a seventh stop valve and an eighth stop valve; One end of the seventh stop valve serves as the heat source inlet of the three-stage heat exchange unit, and the other end of the seventh stop valve is connected to the heat source inlet of the third heat exchanger. The heat source outlet of the third heat exchanger is connected to one end of the eighth stop valve, and the other end of the eighth stop valve serves as the heat source outlet of the three-stage heat exchange unit.

6. The waste heat recovery system for an air compressor according to claim 1, characterized in that: Also includes: An energy storage unit, used for storing heat energy of the heat generating unit; And / or, a water replenishment unit, used to replenish the circulating water at the cold source end of the heat generating unit.

7. The waste heat recovery system for an air compressor according to claim 6, characterized in that: The energy storage unit comprises: an energy storage device, a ninth stop valve, a tenth stop valve and an eleventh stop valve; One end of the ninth stop valve is connected to the cold source end outlet of the heat generating unit; the other end of the ninth stop valve is connected to the energy storage inlet of the energy storage device, and the energy storage outlet of the energy storage device is respectively connected to one end of the tenth stop valve and one end of the eleventh stop valve; The other end of the tenth stop valve is connected to the cold source end inlet of the heat generating unit, and the other end of the eleventh stop valve is connected to the cold source end outlet of the heat generating unit; The water replenishment unit comprises: a water replenishment solenoid valve, one end of which is connected to a water replenishment source, and the other end of which is connected to an inlet of a cold source end of the heat generating unit.

8. The waste heat recovery system for an air compressor according to claim 7, characterized in that: Also includes: A first booster pump, which is arranged in a pipeline connecting the energy storage outlet of the energy storage device and the cold source end outlet of the heat generating unit; And / or, a second booster pump, wherein the second booster pump is arranged in the pipeline where the cold source end inlet of the heat generating unit is located.

9. The waste heat recovery system for an air compressor according to any one of claims 1 to 8, characterized in that: When the oil temperature of the first control valve is lower than a first preset temperature, the first control valve is in the first flow direction; When the oil temperature at the first control valve is greater than the first preset temperature, the first control valve is in the second flow direction; When the oil temperature at the outlet of the heat source end of the heat generating unit is greater than the second preset temperature, the second control valve is in the third flow direction; When the oil temperature at the outlet of the heat source end of the heat generating unit is lower than the second preset temperature, the second control valve is in the fourth flow direction; Wherein, the first preset temperature is less than or equal to the second preset temperature.

10. A waste incineration power plant, characterized in that: include: N air compressors, N is a positive integer; Each of the air compressors is provided with a waste heat recovery system for the air compressor as claimed in any one of claims 1 to 9; When the first control valve in the waste heat recovery system of the air compressor is in the second flow direction, the second booster pump in the waste heat recovery system of the air compressor is adjusted so that the flow at the cold source end of the heat generating unit in the waste heat recovery system of the air compressor reaches the rated flow.

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