Mine Return Air Waste Heat Cascade Utilization System

Abstract

The present invention provides a stepped utilization system for the waste heat of mine return air, which relates to the technical field of shaft antifreeze heating. The system includes a return air system, a wellhead heater assembly, an underground air intake mechanism, and a heat pump unit. By stepwise utilization of the waste heat of the mine return air, and the return air system and the heat pump unit jointly heat the wellhead heater assembly, the wellhead heater assembly can heat the outdoor air temperature at the wellhead of the underground air intake mechanism. Through the stepped utilization of waste heat, the operation cost for shaft antifreeze in winter can be reduced, alleviating the technical problems existing in the prior art that the heat pump technology consumes a large amount of electric energy, and the applicability of using the mine return air is low, and there are potential safety hazards affecting mine ventilation. It realizes a significant improvement in the comprehensive energy efficiency ratio, can save a large amount of energy, and has a low comprehensive operation cost, effectively reducing environmental pollution. The economic and social benefits are prominent after popularization and application.

Description

Technical Field

[0001] The present invention relates to the technical field of wellbore anti-freezing heating, and particularly to a system for cascaded utilization of waste heat from mine return air. Background Art

[0002] At present, there are mainly two utilization methods for waste heat utilization technology of mine return air: 1. Using heat pump technology to extract heat from mine return air to produce hot water at 45 - 60°C for wellbore anti-freezing; 2. Directly heating fresh air with mine return air to above 2°C, and then sending it to the intake shaft through a large-diameter air duct to achieve wellbore anti-freezing.

[0003] In the prior art, extracting heat through heat pump technology requires a large amount of electric energy as the driving energy, and the average energy efficiency ratio of the system is about 3, that is, to produce 3 kW of heat energy, 1 kW of electric energy needs to be consumed to extract about 2 kW of heat energy from mine return air for heating.

[0004] In the prior art system that directly heats fresh air with mine return air, it is more economical only when the distance between the return air shaft and the intake shaft is relatively close, and the diameter of the conveying air duct is large, occupying a large area and affecting the aesthetics; for shallow mining mountain mines with relatively low underground temperature, because the return air temperature is relatively low, with an average winter return air temperature of about 10 - 13°C, the technology of directly heating fresh air is not applicable; specifically, raising the mine return air temperature of 10°C to 1°C is not enough to heat the same volume of fresh air from -25°C to 2°C, and if the mine return air temperature is raised to negative temperature, it will cause serious problems such as frosting of the heat exchanger, resulting in a large increase in the resistance of the heat exchanger and affecting the safety of mine ventilation. Summary of the Invention

[0005] The purpose of the present invention is to provide a system for cascaded utilization of waste heat from mine return air to alleviate at least one of the technical problems existing in the prior art, such as the heat pump technology consuming a large amount of electric energy, the low applicability of using mine return air, and the potential safety hazard affecting mine ventilation.

[0006] A system for cascaded utilization of waste heat from mine return air provided by the present invention includes: a return air system, a wellhead heater assembly, an underground intake mechanism, and a heat pump unit;

[0007] The wellhead heater assembly includes a first wellhead heater and a second wellhead heater; the first wellhead heater is communicated with the return air system, and the return air system is used to receive the waste heat of mine return air and heat the first wellhead heater;

[0008] The return air system is connected to the heat pump unit after passing through the first wellhead heater. The heat pump unit can absorb the heat energy in the flowing medium of the return air system after passing through the first wellhead heater. The second wellhead heater is connected to the heat pump unit to reheat the heat of the flowing medium of the return air system in the second wellhead heater.

[0009] The first wellhead heater and the second wellhead heater are respectively used to heat the outdoor air temperature at the wellhead of the underground air intake mechanism, and the heated air is mixed and enters the underground air intake mechanism. The air temperature range entering the mine at the wellhead of the underground air intake mechanism is greater than or equal to 2°C.

[0010] In a preferred embodiment of the present invention, the heat pump unit includes an evaporator and a condenser. The evaporator and the condenser are connected. The evaporator is connected to the return air system and is used to absorb the heat energy in the flowing medium of the return air system after passing through the first wellhead heater, so as to transfer the heat of the flowing medium of the return air system to the condenser. The condenser is connected to the second wellhead heater and is used to heat the second wellhead heater.

[0011] In a preferred embodiment of the present invention, it further includes an auxiliary heat source and an energy storage device;

[0012] The auxiliary heat source is connected to the second wellhead heater through the energy storage device and is used to assist in heating the second wellhead heater;

[0013] The condenser is connected in parallel with the energy storage device so that the condenser and the energy storage device respectively heat the second wellhead heater.

[0014] In a preferred embodiment of the present invention, the energy storage device includes a first coil heater, a second coil heater and a heat preservation water tank;

[0015] Both the first coil heater and the second coil heater are arranged in the heat preservation water tank. The first coil heater is connected to the second wellhead heater, the second coil heater is connected to the auxiliary heat source, and the first coil heater is connected in parallel with the condenser.

[0016] In a preferred embodiment of the present invention, it further includes a temperature control valve;

[0017] The temperature control valve is arranged between the first coil heater and the second wellhead heater, and the temperature sensor of the temperature control valve is located inside the heat preservation water tank. The temperature control valve is used to detect the temperature of the heat preservation water tank to control the opening or closing of the first coil heater and the second wellhead heater.

[0018] In a preferred embodiment of the present invention, the return air system includes a return air heat exchanger, a return air shaft, and a return air conveying device;

[0019] The return air shaft is connected to the return air heat exchanger through the return air conveying device. The return air shaft is connected to the interior of the mine, and the return air heat exchanger is connected to the first wellhead heater and the second wellhead heater through the mine interior shaft and roadway;

[0020] The return air heat exchanger is connected to the evaporator, and the return air heat exchanger can transfer the waste heat of the flowing medium after heat exchange with the first wellhead heater to the evaporator.

[0021] In a preferred embodiment of the present invention, the return air conveying device includes a return air heat exchange duct, a main mine fan, and a diffuser;

[0022] Both ends of the return air heat exchange duct are respectively connected to the return air heat exchanger and the return air shaft. The main mine fan and the diffuser are both arranged in the return air heat exchange duct. The main mine fan is located at one end of the return air heat exchange duct close to the return air shaft, and the diffuser is located at one end of the return air heat exchange duct close to the return air heat exchanger.

[0023] In a preferred embodiment of the present invention, the return air heat exchanger is internally provided with a flowing medium, and the flowing medium is internally provided with antifreeze.

[0024] In a preferred embodiment of the present invention, the underground air intake mechanism includes a wellhead house and an air intake shaft;

[0025] Both the first wellhead heater and the second wellhead heater are arranged in the wellhead house, and the wellhead house is connected to the air intake shaft. The first wellhead heater and the second wellhead heater are used to heat the air temperature in the wellhead house so that the heated air in the wellhead house is conveyed to the mine.

[0026] In a preferred embodiment of the present invention, it further includes a first circulating water pump, a second circulating water pump, and a third circulating water pump;

[0027] The first circulating water pump is arranged between the return air system and the first wellhead heater and is respectively connected to the return air system and the first wellhead heater;

[0028] The second circulating water pump is arranged between the energy storage device and the second wellhead heater and is respectively connected to the auxiliary heat source and the second wellhead heater;

[0029] The third circulating water pump is arranged between the auxiliary heat source and the energy storage device and is respectively connected to the auxiliary heat source and the energy storage device.

[0030] A system for cascaded utilization of waste heat from mine return air provided by the present invention includes: a return air system, a wellhead heater assembly, an underground air intake mechanism, and a heat pump unit; through the transportation of the return air system, the cascaded utilization of the waste heat of the mine return air can be carried out. After the waste heat of the mine return air is used to heat the first wellhead heater through the return air system, the heat will be absorbed again by the heat pump unit through a flowing medium. Thus, through the secondary waste heat utilization of the heat pump unit, the second wellhead heater can be heated secondly. The wellhead heater assembly is heated jointly by the return air system and the heat pump unit, so that the outdoor air temperature at the wellhead of the underground air intake mechanism can be heated by the wellhead heater assembly; to make the temperature range of the air entering the mine at the wellhead of the underground air intake mechanism be greater than or equal to 2°C; through the cascaded utilization of waste heat, the operation cost for preventing the freezing of the mine shaft in winter can be greatly reduced, alleviating the technical problems existing in the prior art that the heat pump technology consumes a large amount of electric energy, and the applicability of using the mine return air is low, and there are potential safety hazards affecting mine ventilation; realizing a substantial increase in the comprehensive energy efficiency ratio, saving a large amount of energy, having a low comprehensive operation cost, being environmentally friendly, effectively reducing environmental pollution, and having prominent economic and social benefits after popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0032] Figure 1 It is a schematic diagram of the overall structure of the system for cascaded utilization of waste heat from mine return air provided by an embodiment of the present invention.

[0033] Reference numerals: 100 - return air system; 101 - return air heat exchanger; 102 - return air shaft; 103 - return air conveying device; 113 - return air heat exchange air duct; 123 - main mine fan; 133 - diffuser; 200 - wellhead heater assembly; 201 - first wellhead heater; 202 - second wellhead heater; 300 - auxiliary heat source; 400 - energy storage device; 401 - first coil heater; 402 - second coil heater; 403 - insulation water tank; 500 - underground air intake mechanism; 501 - wellhead house; 502 - intake shaft; 600 - heat pump unit; 601 - evaporator; 602 - condenser; 700 - temperature control valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0035] As Figure 1 shown, a stepped utilization system for the waste heat of mine return air provided in this embodiment includes: a return air system 100, a wellhead heater assembly 200, an underground intake air mechanism 500, and a heat pump unit 600; the wellhead heater assembly 200 includes a first wellhead heater 201 and a second wellhead heater 202; the first wellhead heater 201 is connected to the return air system 100, and the return air system 100 is used to receive the waste heat of the mine return air and heat the first wellhead heater 201; after passing through the first wellhead heater 201, the return air system 100 is connected to the heat pump unit 600, and the heat pump unit 600 can absorb the heat energy in the flowing medium of the return air system 100 after passing through the first wellhead heater 201, and the second wellhead heater 202 is connected to the heat pump unit 600 to reheat the heat of the flowing medium of the return air system 100 in the second wellhead heater 202; the first wellhead heater 201 and the second wellhead heater 202 are respectively used to heat the outdoor air temperature at the wellhead of the underground intake air mechanism 500, and the heated air is mixed and enters the underground intake air mechanism 500, and the temperature range of the air entering the mine at the wellhead of the underground intake air mechanism 500 is greater than or equal to 2°C.

[0036] Furthermore, a stepped utilization system for the waste heat of mine return air provided in this embodiment further includes an auxiliary heat source 300 and an energy storage device 400. The auxiliary heat source 300 is connected to the wellhead heater assembly 200 through the energy storage device 400 and is used to assist in heating the wellhead heater assembly 200;

[0037] In this embodiment, both ends of the return air system 100 are respectively connected to the underground and the wellhead heater assembly 200. By utilizing the waste heat of the mine return air, the freezing prevention of the shaft of the underground intake air mechanism 500 can be achieved, and finally, it can be ensured that the temperature range of the air entering the mine at the wellhead of the underground intake air mechanism 500 is greater than or equal to 2°C; it should be noted that the stepped utilization system for the waste heat of mine return air provided in this embodiment is mainly used for the freezing prevention of the shaft.

[0038] During the operation of the mine return air waste heat cascade utilization system, in order to ensure that the wellhead heater assembly 200 continuously heats the air temperature at the wellhead of the underground air intake mechanism 500, and in order to better utilize the waste heat of the return air system 100 in a cascade manner, a heat pump unit 600 is provided between the return air system 100 and the wellhead heater assembly 200. The evaporator 601 of the heat pump unit can absorb the heat in the return air system 100 again after heating the wellhead heater assembly 200, and reuse the heat in the return air system 100, realizing the cascade utilization of the waste heat of the return air system 100.

[0039] Optionally, the auxiliary heat source 300 can be the waste heat of an air compressor, the waste heat of the cylinder jacket water of a gas generator, the waste heat of the exhaust gas of a gas generator, or an electric heater.

[0040] Among them, the wellhead heater assembly 200 is a device for directly heating the air at the wellbore of the underground air intake mechanism 500. When the return air system 100 is used to directly heat the wellhead heater assembly 200, it may not be possible to raise the temperature of the air entering the mine at the wellhead of the underground air intake mechanism 500 to above 2°C. Therefore, an auxiliary heat source 300 and an energy storage device 400 can be provided to heat the wellhead heater assembly 200 again, so that the air at the wellhead of the underground air intake mechanism 500 is mixed with the air heated by the auxiliary heat source 300 and the energy storage device 400 after being heated by the return air system 100, and the temperature of the mixed air is maintained above 2°C, realizing the anti-freezing effect of the wellbore of the underground air intake mechanism 500.

[0041] A mine return air waste heat cascade utilization system provided by this embodiment includes: a return air system 100, a wellhead heater assembly 200, an auxiliary heat source 300, an energy storage device 400, and an underground intake air mechanism 500; through the conveying action of the return air system 100, the waste heat of the mine return air can be utilized in a cascade manner. After the heat of the mine return air is used to heat the wellhead heater assembly 200 through the return air system 100, the heat will be absorbed by the heat pump unit 600 again. Thus, through the reuse of waste heat by the heat pump unit 600, the wellhead heater assembly 200 can be heated again. In addition, since the heat pump unit 600 and the energy storage device 400 are connected in parallel, the components of the energy storage device 400 and the heat pump unit 600 for heating the wellhead heater assembly 200 are the same. The wellhead heater assembly 200 is heated jointly by the return air system 100, the heat pump unit 600, and the auxiliary heat source 300, so that the outdoor air temperature at the wellhead of the underground intake air mechanism 500 can be heated by the wellhead heater assembly 200; to make the temperature range of the air entering the mine at the wellhead of the underground intake air mechanism 500 greater than or equal to 2°C; it can greatly reduce the operation cost for freezing prevention of the shaft in winter, alleviate the technical problems existing in the prior art that the heat pump technology requires a large amount of electric energy consumption, and the applicability of using the mine return air is low, and there are potential safety hazards affecting mine ventilation; it realizes a substantial increase in the comprehensive energy efficiency ratio, can save a large amount of energy, and has low comprehensive operation cost, is environmentally friendly, effectively reduces environmental pollution, and has prominent economic and social benefits after popularization and use.

[0042] On the basis of the above embodiment, in a preferred embodiment of the present invention, the heat pump unit 600 includes an evaporator 601 and a condenser 602. The evaporator 601 and the condenser 602 are connected. The evaporator 601 is connected to the return air system 100 and is used to cool the flowing medium inside the return air system 100 to transfer the heat of the flowing medium of the return air system 100 to the condenser 602. The condenser 602 is connected to the wellhead heater assembly 200 and is used to heat the wellhead heater assembly 200; the condenser 602 is connected in parallel with the energy storage device 400.

[0043] Among them, the heat pump unit 600 can use the condenser 602 to heat the wellhead heater assembly 200 again after absorbing the heat; it should be noted that the condenser 602 is connected in parallel with the energy storage device 400, and both the condenser 602 and the energy storage device 400 heat the second wellhead heater 202 of the wellhead heater assembly 200.

[0044] The heat pump unit 600 may include an evaporator 601, a condenser 602, a compressor, and an expansion valve. Since the heat pump unit 600 can adopt a scroll heat pump unit 600, a screw heat pump unit 600, or a centrifugal heat pump unit 600, the specific structure is the same as that of the heat pump unit 600 in the prior art and will not be elaborated here.

[0045] In a preferred embodiment of the present invention, the return air system 100 includes a return air heat exchanger 101, a return air shaft 102, and a return air conveying device 103; the return air shaft 102 is communicated with the return air heat exchanger 101 through the return air conveying device 103, and the return air shaft 102 is communicated with the inside of the mine for conveying the return air heat energy in the mine, and the return air heat exchanger 101 is communicated with the wellhead heater assembly 200; the return air heat exchanger 101 is connected to the evaporator 601 for exchanging the waste heat after heat exchange with the wellhead heater assembly 200 into the evaporator 601.

[0046] Among them, the return air heat exchanger 101 can perform air-water heat exchange on the hot air conveyed into by the return air shaft 102, so as to heat the flowing medium inside the return air heat exchanger 101. The flowing medium inside the return air heat exchanger 101 will heat the wellhead heater assembly 200 by means of water-air heat exchange. When the heating of the wellhead heater assembly 200 is completed, the flowing medium that returns at this time will exchange heat through the evaporator 601, and the evaporator 601 will absorb the waste heat of the flowing medium. The heat of the evaporator 601 will be discharged to the condenser 602 through the Freon cycle, and the condenser 602 will heat the wellhead heater assembly 200 by means of the heat absorbed secondarily together with the work energy of the compressor of the heat pump unit 600.

[0047] Optionally, the return air heat exchanger 101 adopts a surface type return air heat exchanger, and the surface type return air heat exchanger is a finned tube type. The return air shaft 102 and the return air conveying device 103 are hermetically connected, and the return air heat exchanger 101 is located inside the return air conveying device 103 and can absorb the waste heat of the mine return air.

[0048] In this embodiment, the mine return air with a temperature of 10 - 13 °C comes out of the return air shaft 102 and is discharged at about 1 °C after the heat is transferred to the circulating flowing medium at -7 °C in the return air heat exchanger 101. At this time, the temperature of the flowing medium in the return air heat exchanger 101 will rise to about 6 °C. At this time, the flowing medium will be conveyed to the first wellhead heater 201 to heat the outdoor air. At this time, the temperature of the flowing medium in the return air heat exchanger 101 will drop to -1 °C. At the same time, the flowing medium at -1 °C in the return air heat exchanger 101 will enter the evaporator 601 of the heat pump unit 600. In the evaporator 601 of the heat pump unit 600, the energy of the flowing medium is extracted and the temperature drops to about -7 °C and then enters the return air heat exchanger 101 again to realize the cycle.

[0049] Further, in a preferred embodiment of the present invention, to ensure the conveyance of mine return air, the return air conveyance device 103 includes a return air heat exchange air duct 113, a mine main fan 123, and a diffuser 133; both ends of the return air heat exchange air duct 113 are respectively connected to the return air heat exchanger 101 and the return air shaft 102, the mine main fan 123 and the diffuser 133 are both arranged in the return air heat exchange air duct 113, and the mine main fan 123 is located at one end of the return air heat exchange air duct 113 close to the return air shaft 102, and the diffuser 133 is located at one end of the return air heat exchange air duct 113 close to the return air heat exchanger 101.

[0050] The mine main fan 123 can drive the return air inside the return air heat exchange air duct 113 for directional conveyance, and the diffuser 133 can make the mine return air contact the return air heat exchanger 101 over a larger area, improving the heat exchange efficiency of the return air heat exchanger 101; optionally, the return air system 100 composed of the return air heat exchanger 101, the return air shaft 102, the return air heat exchange air duct 113, the mine main fan 123, and the diffuser 133 can be entirely replaced by a mine water heat extraction system.

[0051] It should be noted that both the mine main fan 123 and the diffuser 133 are existing structures in the coal mine field, and the specific structures will not be elaborated here.

[0052] In a preferred embodiment of the present invention, a flowing medium is arranged inside the return air heat exchanger 101, and antifreeze is arranged inside the flowing medium.

[0053] Further, antifreeze is arranged in the circulating pipelines connected to the wellhead heater assembly 200. Optionally, ethylene glycol antifreeze can be used as the antifreeze, and the freezing point temperature can be controlled to be about 5°C lower than the local extreme weather temperature through the ethylene glycol antifreeze.

[0054] In a preferred embodiment of the present invention, the wellhead heater assembly 200 includes a first wellhead heater 201 and a second wellhead heater 202; the first wellhead heater 201 is communicated with the return air system 100, the second wellhead heater 202 is connected to the parallel connection point of the condenser 602 and the energy storage device 400, and the first wellhead heater 201 and the second wellhead heater 202 are used to respectively heat the outdoor air temperature at the wellhead of the underground air intake mechanism 500 and make the heated air mix and enter the underground air intake mechanism 500.

[0055] Specifically, the first wellhead heater 201 is connected to the return air heat exchanger 101 of the return air system 100. The heat of the ventilation heat exchanger will heat the outdoor air through the first wellhead heater 201. At this time, the temperature of the outdoor air is the first temperature. The second wellhead heater 202 is connected to the parallel connection point of the condenser 602 and the energy storage device 400. Both the condenser 602 and the energy storage device 400 can transfer heat to the second wellhead heater 202, and then heat the outdoor air through the second wellhead heater 202. At this time, the temperature of the outdoor air is the second temperature. After the air with the first temperature and the air with the second temperature are mixed and heat exchanged, the temperature range of the mixed air is greater than or equal to 2°C.

[0056] Optionally, the first wellhead heater 201 and the second wellhead heater 202 can adopt copper tube and aluminum fin type; moreover, it should be noted that in this embodiment, the connection relationships among the first wellhead heater 201, the second wellhead heater 202, the return air heat exchanger 101, the heat pump unit, and the energy storage device 400 are all connected through pipelines.

[0057] In a preferred embodiment of the present invention, the energy storage device 400 includes a first coil heater 401, a second coil heater 402, and a heat preservation water tank 403; both the first coil heater 401 and the second coil heater 402 are arranged in the heat preservation water tank 403. The first coil heater 401 is connected to the second wellhead heater 202, the second coil heater 402 is connected to the auxiliary heat source 300, and the first coil heater 401 is connected in parallel with the heat pump unit 600.

[0058] Optionally, both the first coil heater 401 and the second coil heater 402 can adopt closed coil heaters, and the materials of the first coil heater 401 and the second coil heater 402 can be copper tubes or stainless steel tubes.

[0059] In this embodiment, the water temperature in the heat preservation water tank 403 is maintained above 75°C. The heat preservation water tank 403 has the function of storing heat. The auxiliary heat source 300 will continuously heat the heat preservation water tank 403. Preferably, the second coil heater 402 is installed at about 1 / 3 of the overall height of the lower part of the heat preservation water tank 403, and the first coil heater 401 is installed at about 1 / 3 of the overall height of the upper part of the heat preservation water tank 403. The second coil heater 402 can transfer the heat source of the auxiliary heat source 300 into the heat preservation water tank 403, so as to continuously heat the water in the heat preservation water tank 403. The first coil heater 401 can absorb heat from the heat preservation water tank 403, so as to heat the second wellhead heater 202.

[0060] In a preferred embodiment of the present invention, it further includes a temperature control valve 700; the temperature control valve 700 is arranged between the first coil heater 401 and the second wellhead heater 202, and the temperature control valve 700 is located inside the heat preservation water tank 403, and is used to detect the temperature of the heat preservation water tank 403 to control the opening or closing of the first coil heater 401 and the second wellhead heater 202.

[0061] Optionally, the temperature control valve 700 adopts a temperature regulating valve. By setting the threshold temperature of the temperature control valve 700, when the detected temperature exceeds the threshold temperature, the temperature control valve 700 is in an open state, and when the detected temperature exceeds the threshold temperature, the temperature control valve 700 will be in a closed state; in this embodiment, the threshold temperature of the temperature control valve 700 is 75 °C. When the temperature in the heat preservation water tank 403 is greater than 75 °C, the temperature control valve 700 is in a normally open state, and at this time, the first coil heater 401 will continuously transfer heat to the second wellhead heater 202.

[0062] In a preferred embodiment of the present invention, the downhole air intake mechanism 500 includes a wellhead house 501 and an air intake shaft 502; the first wellhead heater 201 and the second wellhead heater 202 are both arranged in the wellhead house 501, and the wellhead house 501 is communicated with the air intake shaft 502. The first wellhead heater 201 and the second wellhead heater 202 are used to heat the air temperature in the wellhead house 501 so that the heated air in the wellhead house 501 is transported to the mine shaft.

[0063] Among them, in the case of a relatively low external environmental temperature, all the incoming air in the wellhead house 501 is heated by the first wellhead heater 201 and the second wellhead heater 202 in the wellhead house 501 and the temperature is maintained above 2 °C, and then will enter the air intake shaft 502 in sequence.

[0064] In a preferred embodiment of the present invention, it further includes a first circulating water pump, a second circulating water pump and a third circulating water pump; the first circulating water pump is arranged between the return air system 100 and the first wellhead heater 201 and is respectively communicated with the return air system 100 and the first wellhead heater 201; the second circulating water pump is arranged between the energy storage device 400 and the second wellhead heater 202 and is respectively communicated with the auxiliary heat source 300 and the second wellhead heater 202; the third circulating water pump is arranged between the auxiliary heat source 300 and the energy storage device 400 and is respectively communicated with the auxiliary heat source 300 and the energy storage device 400.

[0065] Since the return air system 100, the wellhead heater assembly 200, the heat pump unit 600, the energy storage device 400 and the auxiliary heat source 300 are all connected by pipelines, in order to ensure the fluidity of the flowing medium, through the power output of the first circulating water pump, the second circulating water pump and the third circulating water pump, the overall heat exchange circulation flow of the flowing medium can be ensured.

[0066] The operation of the mine return air waste heat cascade utilization system provided in this embodiment can be divided into multiple operation modes. For example: During the initial heating operation mode: The heat pump unit 600 stops operating. The mine return air at 10 - 13 °C coming out of the return air shaft 102 transfers heat to the circulating medium at 0 °C (preferably, the circulating medium is water with antifreeze added) in the return air heat exchanger 101 and then is discharged at about 6 °C. The temperature of the circulating medium rises to about 8 °C and enters the first wellhead heater 201 under the action of the circulating pipeline and the first circulating water pump. In the first wellhead heater 201, the outdoor air is heated from about -5 °C to about 5 °C and enters the wellhead house 501; at this time, after the temperature control valve 700 with the function of a temperature sensor detects that the temperature in the heat preservation water tank 403 remains above 75 °C, it adjusts the temperature control valve 700 to open to ensure the heat supply capacity of the heat preservation water tank 403 to fully utilize the auxiliary heat source 300 after completing the energy storage task; it enters the second wellhead heater 202 through the first coil heater 401 via the circulating pipeline. In the second wellhead heater 202, the outdoor air is heated from about -5 °C to about 5 °C and enters the wellhead house 501; after the outdoor air is respectively heated in the first wellhead heater 201 and the second wellhead heater 202, it is mixed in the wellhead house 501 and enters the intake shaft 502, meeting the temperature requirements of the shaft of the intake shaft 502.

[0067] Conventional heating operation mode in normal weather: The heat pump unit 600 starts to operate. First, the mine return air at 10 - 13°C coming out of the return air shaft 102 transfers heat to the circulating medium at -7°C (preferably, the circulating medium is water with antifreeze added) in the return air heat exchanger 101 and then is discharged at about 1°C. The temperature of the circulating medium rises to about 6°C and enters the first wellhead heater 201 under the action of the water circulation pipeline and the first circulation pump. In the first wellhead heater 201, the outdoor air is heated from about -15°C to about -5°C and enters the wellhead house 501. At the same time, the temperature of the circulating medium drops to -1°C and enters the evaporator 601 of the heat pump unit 600. In the evaporator 601 of the heat pump unit 600, the energy of the circulating water is extracted and the temperature drops to about -7°C and then enters the return air heat exchanger 101 again. At this time, after the temperature control valve 700 with a temperature sensor detects that the temperature in the heat preservation water tank 403 remains above 75°C, the temperature control valve 700 is adjusted to open to ensure the heating capacity of the heat preservation water tank 403 to fully utilize the auxiliary heat source 300 after completing the energy storage task. At this time, the heat pump unit 600 is turned on. The evaporator 601 of the heat pump unit 600 extracts energy from the circulating medium at about -1°C and can produce circulating water at about 25°C, which enters the second wellhead heater 202 through the circulating pipeline. In the second wellhead heater 202, the outdoor air is heated from about -15°C to about 15°C and enters the wellhead house 501, and mixes with the air at about -5°C from the first wellhead heater 201 in the wellhead house 501. The mixed temperature is controlled at about 5°C to meet the temperature requirement of the shaft of the intake shaft 502. It should be noted that the circulating water coming out of the second coil heater 402 is in parallel with the condenser 602 of the heat pump unit 600.

[0068] Heating extreme weather operation mode: The heat pump unit 600 starts to operate. First, the mine return air at 10 - 13°C coming out of the return air shaft 102 transfers heat to the circulating medium at -7°C (preferably, the circulating medium is water with antifreeze added) in the return air heat exchanger 101, and then the temperature is reduced to about 1°C and discharged. The temperature of the circulating medium rises to about 6°C and enters the first wellhead heater 201 under the action of the water circulation pipeline and the first circulation pump. In the first wellhead heater 201, the outdoor air is heated from about -25°C to about -10°C and enters the wellhead house 501. At the same time, the temperature of the circulating medium drops to -1°C and enters the evaporator 601 of the heat pump unit 600. In the evaporator 601 of the heat pump unit 600, the energy of the circulating water is extracted and the temperature is reduced to about -7°C and then enters the return air heat exchanger 101 again. At this time, the opening degree of the temperature control valve 700 with a temperature sensor remains 100%, and the heat storage energy of the heat preservation water tank 403 is used for heat release, and at the same time, the heating capacity of the auxiliary heat source 300 is fully utilized. At this time, the heat pump unit 600 is started. The evaporator 601 of the heat pump unit 600 extracts energy from the circulating medium at about -1°C, and can produce temperature circulating water at 35 - 45°C, which enters the second wellhead heater 202 through the circulating pipeline. In the second wellhead heater 202, the outdoor air is heated from about -25°C to about 25°C and enters the wellhead house 501, and mixes with the air at about -10°C from the first wellhead heater 201 in the wellhead house 501. The mixed temperature is controlled at about 5°C to meet the temperature requirement of the shaft of the intake shaft 502.

[0069] The function of the return air system 100 can be replaced by a similar low-temperature heat source system such as a mine water heat exchange system in a similar temperature range.

[0070] The mine return air waste heat cascade utilization system provided by this embodiment realizes the cascade utilization of the energy of the mine return air at 10 - 13°C, meets the shaft anti-freezing requirements while minimizing the power consumption, and at the same time sets the extreme weather auxiliary heat source 300 according to the characteristics of the shaft anti-freezing load, minimizing the system investment to make up for the problem of insufficient return air heat. And it can obtain a zero-cost shaft anti-freezing heat source at the initial stage of winter heating. The cost is 70 - 80% of the investment in the traditional cooling and heating system, saving 40 - 60% of the operation electricity cost, improving the energy utilization rate, being energy-saving and environment-friendly, and having remarkable comprehensive economic benefits.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A mine return air waste heat cascade utilization system, characterized in that, it includes: a return air system, a wellhead heater assembly, an underground intake air mechanism, and a heat pump unit; The wellhead heater assembly includes a first wellhead heater and a second wellhead heater; the first wellhead heater is connected to the return air system, and the return air system is used to receive the waste heat of the mine return air and heat the first wellhead heater; The return air system is connected to the heat pump unit after passing through the first wellhead heater. The heat pump unit can absorb the heat energy in the flowing medium of the return air system after passing through the first wellhead heater. The second wellhead heater is connected to the heat pump unit to reheat the heat of the flowing medium of the return air system to the second wellhead heater; The first wellhead heater and the second wellhead heater are respectively used to heat the outdoor air temperature at the wellhead of the underground intake air mechanism, and the heated air is mixed and enters the underground intake air mechanism. The air temperature range entering the mine at the wellhead of the underground intake air mechanism is greater than or equal to 2°C; The heat pump unit includes an evaporator and a condenser. The evaporator and the condenser are connected. The evaporator is connected to the return air system and is used to absorb the heat energy in the flowing medium of the return air system after passing through the first wellhead heater, so as to transfer the heat of the flowing medium of the return air system to the condenser. The condenser is connected to the second wellhead heater and is used to heat the second wellhead heater; The return air system includes a return air heat exchanger, a return air shaft, and a return air conveying device; the return air shaft is connected to the return air heat exchanger through the return air conveying device. The return air shaft is connected to the inside of the mine, and the return air heat exchanger is connected to the first wellhead heater; the return air heat exchanger is connected to the evaporator, and the return air heat exchanger can transfer the waste heat of the flowing medium after heat exchange with the first wellhead heater to the evaporator; The mine return air waste heat cascade utilization system further includes an auxiliary heat source and an energy storage device; The auxiliary heat source is connected to the second wellhead heater through the energy storage device and is used to assist in heating the second wellhead heater; The condenser is connected in parallel with the energy storage device so that the condenser and the energy storage device respectively heat the second wellhead heater.

2. The mine return air waste heat cascade utilization system according to claim 1, characterized in that, the energy storage device includes a first coil heater, a second coil heater, and a heat preservation water tank; The first coil heater and the second coil heater are both arranged in the heat preservation water tank. The first coil heater is connected to the second wellhead heater. The second coil heater is connected to the auxiliary heat source, and the first coil heater is connected in parallel with the condenser.

3. The mine return air waste heat cascade utilization system according to claim 2, characterized in that, it further includes a temperature control valve; The temperature control valve is arranged between the first coil heater and the second wellhead heater, and the temperature control valve is located inside the heat preservation water tank. The temperature control valve is used to detect the temperature of the heat preservation water tank to control the opening or closing of the first coil heater and the second wellhead heater.

4. The mine return air waste heat cascade utilization system according to claim 1, characterized in that the return air conveying device includes a return air heat exchange air duct, a mine main fan and a diffuser; Both ends of the return air heat exchange air duct are respectively connected to the return air heat exchanger and the return air shaft. The mine main fan and the diffuser are both arranged in the return air heat exchange air duct. The mine main fan is located at one end of the return air heat exchange air duct close to the return air shaft, and the diffuser is located at one end of the return air heat exchange air duct close to the return air heat exchanger.

5. The mine return air waste heat cascade utilization system according to claim 1, characterized in that a flowing medium is arranged inside the return air heat exchanger, and antifreeze is arranged inside the flowing medium.

6. The mine return air waste heat cascade utilization system according to claim 1, characterized in that the underground air intake mechanism includes a wellhead house and an air intake shaft; The first wellhead heater and the second wellhead heater are both arranged in the wellhead house, and the wellhead house is communicated with the air intake shaft. The first wellhead heater and the second wellhead heater are used to heat the air temperature in the wellhead house.

7. The mine return air waste heat cascade utilization system according to claim 1, characterized in that it further includes a first circulating water pump, a second circulating water pump and a third circulating water pump; The first circulating water pump is arranged between the return air system and the first wellhead heater and is respectively communicated with the return air system and the first wellhead heater; The second circulating water pump is arranged between the energy storage device and the second wellhead heater and is respectively communicated with the energy storage device and the second wellhead heater; The third circulating water pump is arranged between the auxiliary heat source and the energy storage device and is respectively communicated with the auxiliary heat source and the energy storage device.

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