A mine parallel compression condensing cascade exhaust air heat pump heating system

Abstract

The present invention relates to a parallel compression condensing cascade exhaust air heat pump heating system for mines, comprising a first-level direct steam heat extraction compression condensation parallel circulation unit, a second-level direct steam heat extraction compression condensation parallel circulation unit, a user-side hot water supply system unit, a second-level heat extraction defrosting unit, and a self-cleaning unit. The present invention utilizes the principle of cascade heat extraction and adopts parallel compression condensation technology to transfer the heat of mine exhaust air to the working medium circulation system inside the system in stages through the working medium direct steam heat exchange method, and then transfers the heat to the heat user return water through the high-temperature condensation heat exchange method, thereby providing high-temperature water to the heat users. The condensation heat exchange side of the present invention adopts a two-stage series connection method, which increases the temperature difference between the supply and return water on the user side, reduces the amount of pipeline construction, and can improve the overall energy efficiency of the heating system.

Description

Technical Field

[0001] The invention relates to the technical field of utilization of waste heat from exhaust air in mines, and in particular to a parallel compression condensing cascade exhaust air heat pump heating system for mines. Background Art

[0002] There is a large amount of mine exhaust air in the construction and production process of coal mines. The exhaust air temperature is about 18℃ all year round, and the relative humidity is close to 100%. It contains a large amount of low-temperature waste heat resources with high recovery value. Coal mines also have heat needs such as winter wellhead antifreeze, hot water for bathing and building heating. Therefore, by effectively utilizing the exhaust air waste heat, energy conservation and emission reduction in coal mines can be further achieved.

[0003] At present, the main methods for utilizing waste heat from mine exhaust air are spray heat extraction, split direct steam heat extraction, partition antifreeze heat extraction and heat pipe heat extraction. From the actual effect, these methods have their own shortcomings and defects. For example, the spray heat exchange method and the indirect antifreeze method need to be combined with a water source heat pump, and the recovery device is large in size, low in efficiency and easy to corrode; the split direct steam method has many connecting pipelines and a large installation project; the heat pipe method has heat transfer limits, complex engineering and large application occasions, and the recovered waste heat has a single purpose. Summary of the invention

[0004] The purpose of the present invention is to address the problems existing in the recovery of waste heat from exhaust air mentioned above, to fully study and master the mechanism and law of changes in the physical parameters of mine exhaust air, to utilize the principle of cascade heat extraction, and to adopt parallel compression condensation technology to propose a mine-use parallel compression condensation cascade exhaust air heat pump heating system with defrosting and self-cleaning functions. The heat of the mine exhaust air is transferred in stages to the working fluid circulation system inside the system through direct steam heat exchange of the working fluid, and then the heat is transferred to the return water of the heat users through high-temperature condensation heat exchange, thereby achieving the purpose of providing high-temperature water to the heat users.

[0005] To achieve the above-mentioned object, the present invention provides a mine parallel compression condensing cascade exhaust air heat pump heating system, comprising a first-level direct steam heat extraction compression condensing parallel circulation unit, a second-level direct steam heat extraction compression condensing parallel circulation unit, a user-side hot water supply system unit, a second-level heat extraction defrosting unit and a self-cleaning unit;

[0006] The first-stage direct evaporation heat extraction compression condensation parallel circulation unit comprises at least two groups of first-stage compression condensing units arranged in parallel, a first-stage liquid storage device, a first-stage working fluid liquid distribution pump, a first-stage non-return valve, at least two groups of first-stage thermal expansion valves and a first-stage exhaust air heat collector arranged in parallel, and a first-stage gas-liquid separator, which are cyclically connected in sequence. A first-stage pressure difference balancing valve is provided between the first-stage liquid storage device and the first-stage gas-liquid separator.

[0007] The secondary direct evaporation heat extraction compression condensation parallel circulation unit comprises at least two groups of parallel-arranged secondary compression condensing units, a secondary liquid storage device, a secondary working fluid liquid distribution pump, a secondary one-way valve, at least two groups of parallel-arranged secondary solenoid valves, at least two groups of parallel-arranged secondary thermal expansion valves and secondary exhaust air heat collectors, and a secondary gas-liquid separator, which are cyclically connected in sequence. A secondary pressure difference balancing valve is provided between the secondary liquid storage device and the secondary gas-liquid separator.

[0008] The user-side hot water supply system unit includes a water collector, a heating circulation pump, a heating check valve, a secondary condensing heat exchanger arranged in the secondary compression condensing unit, a primary condensing heat exchanger arranged in the primary compression condensing unit, and a water distributor which are sequentially connected by pipelines;

[0009] The secondary heat extraction and defrosting unit comprises a defrost pipeline connected with the water distributor and the water collector, a defrost branch pipeline is provided in parallel in the defrost pipeline, the defrost branch pipeline is arranged in each group of secondary exhaust air heat collectors, and a defrost solenoid valve is provided on the defrost branch pipeline;

[0010] The self-cleaning unit includes a water tank, a cleaning circulation pump, a cleaning one-way valve, a spray head and a cleaning solenoid valve arranged on the water inlet side of the spray head, which are connected in sequence by pipelines. The spray head is arranged in parallel on the air inlet side of each group of first-stage exhaust air heat collectors.

[0011] Preferably, the mine exhaust air passes through a primary exhaust air heat exchanger and a secondary exhaust air heat exchanger in sequence.

[0012] Preferably, the user-side hot water supply system unit further comprises a water replenishment unit arranged on the water inlet side of the heating circulation pump, and the water replenishment unit comprises a water replenishment tank, a water replenishment circulation pump, and a water replenishment check valve which are sequentially connected to a replenishment water source.

[0013] Preferably, when the intake and exhaust pressure difference is greater than the set value, the first-level pressure difference balancing valve is opened, and the working fluid is mixed with the working fluid from the first-level exhaust air heat exchanger from the first-level liquid storage tank through the first-level pressure difference balancing valve and then enters the first-level gas-liquid separator; when the intake and exhaust pressure difference is less than or equal to the set value, the first-level pressure difference balancing valve is closed.

[0014] Preferably, when the intake and exhaust pressure difference is greater than the set value, the secondary pressure difference balancing valve opens, and the working fluid enters the secondary gas-liquid separator after being mixed with the working fluid from the secondary exhaust air heat exchanger through the secondary pressure difference balancing valve from the secondary liquid storage tank; when the intake and exhaust pressure difference is less than or equal to the set value, the secondary pressure difference balancing valve is closed.

[0015] Preferably, in the defrosting condition, the secondary heat extraction and defrosting unit performs rotational defrosting on one or more groups of secondary exhaust air heat collectors.

[0016] Preferably, the secondary heat extraction defrost unit performs rotational defrosting by controlling the opening and closing of the defrost solenoid valve on each defrost branch line.

[0017] Preferably, during self-cleaning, the self-cleaning unit performs rotational cleaning on one or more groups of primary exhaust air heat exchangers in sequence.

[0018] Preferably, the self-cleaning unit performs rotational cleaning by controlling the opening and closing of each cleaning solenoid valve.

[0019] Based on the above technical solution, the advantages of the present invention are:

[0020] 1. The mine adopts a cascade heat extraction method for air exhaustion, which further improves the energy recovery rate and realizes the maximum effective utilization of waste heat resources;

[0021] 2. This system adopts parallel compression condensation mode, which greatly reduces the installation work of connecting pipes, effectively reduces engineering costs and improves the energy efficiency and reliability of the heating system;

[0022] 3. A separate defrost pipeline for the secondary exhaust air heat exchanger is configured to further improve the heat exchange efficiency on the evaporation side of the system by defrosting the exhaust air heat exchangers in groups and rotation;

[0023] 4. The condensing heat exchange side adopts a two-stage series connection method, which can increase the temperature difference between the supply and return water on the user side and reduce the amount of pipeline construction. In addition, it can improve the overall energy efficiency of the heating system;

[0024] 5. This system further adjusts the suction pressure and exhaust pressure through the pressure differential balancing valve to ensure the operating stability of the compression condensing unit;

[0025] 6. The main liquid circuit of this system is equipped with a working fluid distribution pump, which can reduce the loss of infusion, make the evaporation temperature more uniform, and improve the heat extraction efficiency of the system;

[0026] 7. The fin self-cleaning system is equipped to adapt to the harsh working conditions of mines with lack of air and high dust. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0028] Figure 1 This is a schematic diagram of a parallel compression condensing cascade exhaust air heat pump heating system for mines. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments.

[0030] The mine parallel compression condensing cascade exhaust air heat pump heating system of the present invention is divided into five parts, including a first-level direct steam heat extraction compression condensation parallel circulation unit, a second-level direct steam heat extraction compression condensation parallel circulation unit, a user-side hot water supply system unit, a second-level heat extraction defrosting unit and a self-cleaning unit. Figure 1 As shown, a preferred embodiment of the present invention is shown.

[0031] Specifically, the first-stage direct evaporation heat extraction compression condensation parallel circulation unit includes at least two groups of first-stage compression condensing units 1-1 arranged in parallel, a first-stage liquid storage tank 2-1, a first-stage working fluid distribution pump 4-1, a first-stage non-return valve 8-1, at least two groups of first-stage thermal expansion valves 6-1 and a first-stage exhaust air heat collector 5-1 arranged in parallel, and a first-stage gas-liquid separator 3-1, which are cyclically connected in sequence. A first-stage pressure difference balancing valve 9-1 is provided between the first-stage liquid storage tank 2-1 and the first-stage gas-liquid separator 3-1.

[0032] The first-level differential pressure balancing valve 9-1 is used to adjust the exhaust pressure and the suction pressure. Preferably, when the suction and exhaust pressure difference is greater than the set value, the first-level differential pressure balancing valve 9-1 is opened, and the working fluid is mixed with the working fluid from the first-level exhaust air heat collector 5-1 from the first-level liquid storage tank 2-1 through the first-level differential pressure balancing valve 9-1 and then enters the first-level gas-liquid separator 3-1; when the suction and exhaust pressure difference is less than or equal to the set value, the first-level differential pressure balancing valve 9-1 is closed.

[0033] The secondary direct evaporation heat extraction compression condensation parallel circulation unit includes at least two groups of parallel-arranged secondary compression condensing units 1-2, a secondary liquid storage tank 2-2, a secondary working fluid distribution pump 4-2, a secondary one-way valve 8-2, at least two groups of parallel-arranged secondary solenoid valves 7-2, at least two groups of parallel-arranged secondary thermal expansion valves 6-2 and secondary exhaust air heat collectors 5-2, and a secondary gas-liquid separator 3-2, which are cyclically connected in sequence. A secondary pressure difference balancing valve 9-2 is provided between the secondary liquid storage tank 2-2 and the secondary gas-liquid separator 3-2.

[0034] Among them, the secondary pressure differential balancing valve 9-2 is used to adjust the exhaust pressure and the suction pressure. Preferably, when the suction and exhaust pressure difference is greater than the set value, the secondary pressure differential balancing valve 9-2 is opened, and the working fluid is mixed with the working fluid from the secondary exhaust air heat collector 5-5 from the secondary liquid storage tank 2-2 through the secondary pressure differential balancing valve 9-2 and then enters the secondary gas-liquid separator 3-2; when the suction and exhaust pressure difference is less than or equal to the set value, the secondary pressure differential balancing valve 9-2 is closed.

[0035] Furthermore, the user-side hot water supply system unit includes a water collector 13-2, a heating circulation pump 12-3, a heating check valve 8-4, a secondary condensing heat exchanger arranged in the secondary compression condensing unit 1-2, a primary condensing heat exchanger arranged in the primary compression condensing unit 1-1, and a water distributor 13-1, which are sequentially connected by pipelines. Preferably, the user-side hot water supply system unit also includes a water replenishment unit arranged on the water inlet side of the heating circulation pump 12-3, and the water replenishment unit includes a water replenishment tank 11-2, a water replenishment circulation pump 12-2, and a water replenishment check valve 8-5, which are sequentially connected to the water replenishment source.

[0036] The secondary heat extraction and defrosting unit comprises a defrost pipeline connected with the water distributor 13-1 and the water collector 13-2, a defrost branch pipeline is provided in parallel in the defrost pipeline, the defrost branch pipeline is arranged in each group of secondary exhaust air heat collectors 5-2, and a defrost solenoid valve 7-3 is provided on the defrost branch pipeline.

[0037] like Figure 1 As shown, the self-cleaning unit includes a water tank 11-1, a cleaning circulation pump 12-1, a cleaning one-way valve 8-3, a spray head 10 and a cleaning solenoid valve 7-1 arranged on the water inlet side of the spray head 10, which are connected in sequence by pipelines. The spray head 10 is arranged in parallel on the air inlet side of each group of first-stage exhaust air heat collectors 5-1.

[0038] Preferably, the mine exhaust air passes through the primary exhaust air heat exchanger 5-1 and the secondary exhaust air heat exchanger 5-2 in sequence to ensure that the dust in the exhaust air is enriched and cleaned on the primary exhaust air heat exchanger 5-1, while ensuring that no frost is generated on the primary exhaust air heat exchanger 5-1.

[0039] Preferably, in the defrosting condition, the secondary heat extraction defrosting unit performs rotational defrosting on one or more groups of secondary exhaust air heat collectors 5-2 in turn. Preferably, the secondary heat extraction defrosting unit performs rotational defrosting by controlling the opening and closing of the defrosting solenoid valve 7-3 on each defrosting branch line.

[0040] Furthermore, during self-cleaning, the self-cleaning unit performs rotational cleaning on one or more groups of primary exhaust air heat exchangers 5-1 in sequence. Preferably, the self-cleaning unit performs rotational cleaning by controlling the opening and closing of each cleaning solenoid valve 7-1.

[0041] To further illustrate the working principle of the mine parallel compression condensing cascade exhaust air heat pump heating system of the present invention, the working process of the present invention is described below:

[0042] 1) One-stage direct evaporation heat extraction compression condensation parallel cycle process

[0043] In this process, the working fluid liquid is respectively gathered from the first-stage compression and condensing unit 1-1 to the first-stage liquid storage tank 2-1, flows through the first-stage working fluid distribution pump 4-1 and the first-stage non-return valve 8-1, and then passes through the first-stage thermal expansion valve 6-1 to enter the first-stage exhaust air heat exchanger 5-1. After the working fluid undergoes an endothermic evaporation process, it is gathered and enters the first-stage gas-liquid separator 3-1, and then enters the first-stage compression and condensing unit 1-1 again, thereby completing the first-stage direct evaporation heat extraction compression and condensation parallel cycle process.

[0044] 2) Two-stage direct evaporation heat extraction compression condensation parallel cycle process

[0045] In this process, during the secondary working medium heat extraction cycle, the secondary solenoid valve 7-2 is opened. The liquid working medium is respectively merged from the secondary compression condensing unit 1-2 to the secondary liquid storage tank 2-2, flows through the secondary working medium liquid distribution pump 4-2 and the secondary one-way valve 8-2, and then passes through the secondary solenoid valve 7-2 and the secondary thermal expansion valve 6-2 to enter the secondary exhaust air heat collector 5-2. After the working medium undergoes an endothermic evaporation process, it is merged and enters the secondary gas-liquid separator 3-2, and then enters the secondary compression condensing unit 1-2 again, thereby completing the secondary direct evaporation heat extraction compression condensation parallel cycle process.

[0046] 3) User-side heating process

[0047] In this process, the return water of the heat user enters the collector 13-2 through the ball valve, passes through the heating circulation pump 12-3, the heating check valve 8-4, and the ball valve, and then enters the secondary compression condensing unit 1-2 through the ball valve to absorb heat. After merging, it enters the primary compression condensing unit 1-1 through each ball valve to absorb heat again. After being aggregated, it flows to the heat user through the ball valve and the water distributor 13-1, thereby completing the heating process on the user side.

[0048] The water replenishment unit is activated according to the water level. For example, when the system water level is lower than the set value, the water replenishment pump 12-2 is turned on, and the tap water enters the water replenishment tank 11-2 through the ball valve, and then enters the water collector 13-2 through the ball valve, the water replenishment pump 12-2, the water replenishment check valve 8-5 and the ball valve; when the system water level is greater than or equal to the set value, the water replenishment pump 12-2 is turned off.

[0049] 4) Secondary heat removal and defrosting process

[0050] In the defrosting condition, each group or multiple groups of secondary exhaust air heat exchangers 5-2 are defrosted in rotation in turn. For example, when the first group of secondary exhaust air heat exchangers 5-2 are defrosted, one defrost solenoid valve 7-3 is opened, and the other defrost solenoid valves 7-3 are closed, and part of the high-temperature water in the water distributor 13-1 enters a group of secondary exhaust air heat exchangers 5-2 through the ball valve and the defrost solenoid valve 7-3, and after heat release and defrosting, enters the water collector 13-2 through the ball valve, and mixes with the return water of the heat user, thereby completing the defrosting process of the first group of secondary exhaust air heat exchangers 5-2, and then the other secondary exhaust air heat exchangers 5-2 are defrosted in rotation in turn, and the defrosting process is the same as above.

[0051] 5) Self-cleaning process

[0052] In this process, each group or multiple groups of first-stage exhaust air heat exchangers 5-1 are cleaned in rotation. For example, when cleaning the first-stage exhaust air heat exchanger 5-1, the circulation pump 12-1 is turned on, one of the cleaning solenoid valves 7-1 is turned on, and the other cleaning solenoid valves 7-1 are closed. The tap water enters the water tank 11-1 through the ball valve, and then enters the spray head 10 through the cleaning circulation pump 12-1, the cleaning check valve 8-3, the ball valve, and the cleaning solenoid valve 7-1, and the surface of the first-stage exhaust air heat exchanger 5-1 is sprayed and cleaned, thereby completing the self-cleaning process of the first group of first-stage exhaust air heat exchangers 5-1, and then the remaining first-stage exhaust air heat exchangers 5-1 are self-cleaned in rotation in turn, and the self-cleaning process is the same as above.

[0053] The mine parallel compression condensing cascade exhaust air heat pump heating system of the present invention adopts a cascade heat extraction method for mine exhaust air, and the energy recovery rate is further improved, which can realize the maximum effective utilization of waste heat resources; it adopts a parallel compression condensation method, which greatly reduces the installation engineering workload of connecting pipelines, effectively reduces engineering costs and improves the energy efficiency and reliability of the heating system; by separately configuring a secondary exhaust air heat collector defrosting pipeline, the exhaust air heat collectors are defrosted in groups and rotationally, thereby further improving the heat exchange efficiency of the evaporation side of the system; the condensation heat exchange side adopts a two-stage series method, which can increase the temperature difference of supply and return water on the user side and reduce the amount of pipeline construction, and can also improve the overall energy efficiency of the heating system; the suction pressure and exhaust pressure are further adjusted by the pressure difference balance valve to ensure the operating stability of the compression condensing unit; the main liquid circuit is equipped with a working fluid dosing pump, which can reduce the infusion loss, make the evaporation temperature more uniform, and improve the heat extraction efficiency of the system; a fin self-cleaning system is provided to adapt to the harsh working conditions of mine exhaust air and high dust.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A parallel compression condensing cascade exhaust air heat pump heating system for mining, characterized by: It includes a primary direct steam heat extraction compression condensation parallel circulation unit, a secondary direct steam heat extraction compression condensation parallel circulation unit, a user-side hot water supply system unit, a secondary heat extraction defrosting unit and a self-cleaning unit; The first-stage direct evaporation heat extraction compression condensation parallel circulation unit comprises at least two groups of first-stage compression condensing units (1-1) arranged in parallel, a first-stage liquid storage device (2-1), a first-stage working fluid liquid distribution pump (4-1), a first-stage non-return valve (8-1), at least two groups of first-stage thermal expansion valves (6-1) and a first-stage exhaust air heat collector (5-1) arranged in parallel, which are cyclically connected in sequence. A first-stage pressure difference balancing valve (9-1) is provided between the first-stage liquid storage device (2-1) and the first-stage gas-liquid separator (3-1); The two-stage direct evaporation heat extraction compression condensation parallel circulation unit comprises at least two groups of two-stage compression condensing units (1-2) arranged in parallel, a two-stage liquid storage device (2-2), a two-stage working fluid liquid distribution pump (4-2), a two-stage one-way valve (8-2), at least two groups of two-stage solenoid valves (7-2) arranged in parallel, at least two groups of two-stage thermal expansion valves (6-2) and two-stage exhaust air heat collectors (5-2) arranged in parallel, and a two-stage gas-liquid separator (3-2), wherein a two-stage pressure difference balancing valve (9-2) is arranged between the two-stage liquid storage device (2-2) and the two-stage gas-liquid separator (3-2); The user-side hot water supply system unit comprises a water collector (13-2), a heating circulation pump (12-3), a heating check valve (8-4), a secondary condensing heat exchanger arranged in the secondary compression condensing unit (1-2), a primary condensing heat exchanger arranged in the primary compression condensing unit (1-1), and a water distributor (13-1) which are sequentially connected by pipelines, and the user-side hot water supply system unit also comprises a water replenishment unit arranged on the water inlet side of the heating circulation pump (12-3); The secondary heat extraction and defrosting unit comprises a defrost pipeline connected to the water distributor (13-1) and the water collector (13-2), a defrost branch pipeline is provided in parallel in the defrost pipeline, the defrost branch pipeline is arranged in each group of secondary exhaust air heat collectors (5-2), and a defrost solenoid valve (7-3) is provided on the defrost branch pipeline; The self-cleaning unit comprises a water tank (11-1), a cleaning circulation pump (12-1), a cleaning check valve (8-3), a spray head (10), and a cleaning solenoid valve (7-1) arranged on the water inlet side of the spray head (10), which are connected in sequence by pipelines. The spray head (10) is arranged in parallel on the air inlet side of each group of primary exhaust air heat collectors (5-1); When the suction and exhaust pressure difference is greater than the set value, the first-level pressure difference balancing valve (9-1) is opened, and the working medium is mixed with the working medium from the first-level exhaust air heat exchanger (5-1) through the first-level pressure difference balancing valve (9-1) and then enters the first-level gas-liquid separator (3-1), and the second-level pressure difference balancing valve (9-2) is opened, and the working medium is mixed with the working medium from the second-level exhaust air heat exchanger (5-2) through the second-level pressure difference balancing valve (9-2) and then enters the second-level gas-liquid separator (3-2); when the suction and exhaust pressure difference is less than or equal to the set value, the first-level pressure difference balancing valve (9-1) is closed, and the second-level pressure difference balancing valve (9-2) is closed.

2. The cascade exhaust air heat pump heating system according to claim 1 is characterized in that: The mine exhaust air passes through the primary exhaust air heat exchanger (5-1) and the secondary exhaust air heat exchanger (5-2) in sequence.

3. The cascade exhaust air heat pump heating system according to claim 1 is characterized in that: In the defrosting condition, the secondary heat extraction and defrosting unit performs rotational defrosting on one or more groups of secondary exhaust air heat collectors (5-2).

4. The cascade exhaust air heat pump heating system according to claim 3 is characterized in that: The two-stage heat extraction defrosting unit performs rotational defrosting by controlling the opening and closing of the defrosting solenoid valve (7-3) on each defrosting branch line.

5. The cascade exhaust air heat pump heating system according to claim 1 is characterized in that: During self-cleaning, the self-cleaning unit performs rotational cleaning on one or more groups of primary exhaust air heat exchangers (5-1) in sequence.

6. The cascade exhaust air heat pump heating system according to claim 5, characterized in that: The self-cleaning unit performs rotational cleaning by controlling the opening and closing of each cleaning solenoid valve (7-1).

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