Totally-closed low-grade waste heat recovery power generation recycling system

Abstract

The invention relates to a totally-closed low-grade waste heat recovery power generation recycling system which comprises a cold compressor, a first heat exchanger, a buffer tank, a turbine, an induced draft fan and a second heat exchanger through which a medium sequentially passes, and a low-grade heat source which exchanges heat with the medium flows in the second heat exchanger. When the system is used, a low-grade heat source enters the second heat exchanger, a medium absorbs heat of the low-grade heat source, then enters the cold compressor and is compressed to form a high-temperature and high-pressure medium, the medium transmits the heat to heat-carrying fluid in the first heat exchanger to form a high-pressure and low-temperature medium, and the medium enters the buffer tank to be stored; when the pressure of the medium reaches a set value of the constant-pressure valve, the constant-pressure valve is opened, the medium pushes the impeller to rotate and drives the rotating shaft of the generator to rotate for power generation, the medium after power generation is low-pressure and low-temperature and is fed into the second heat exchanger under the action of the induced draft fan to form circulation, and the system fully absorbs and utilizes heat of a low-grade heat source, so that heat pollution can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of machinery, in particular to the field of mechanical component technology, and specifically refers to a fully enclosed low-grade waste heat recovery power generation and reuse system. Background Art

[0002] During the production process of enterprises, many hot fluids between 40℃-60℃, including water and gas, are discharged, which not only causes energy waste (especially existing thermal power generation enterprises), but also pollutes the environment, that is, thermal pollution. For this reason, a low-grade heat recovery device is urgently needed. The difficulty of low-grade waste heat recovery lies in its reuse. This technology designs a fully enclosed impeller to recover waste heat for power generation, solving the problem of low-grade waste heat recovery. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a fully enclosed low-grade waste heat recovery power generation and reuse system for recovering low-grade heat.

[0004] The present invention is achieved through the following technical scheme: a fully enclosed low-grade waste heat recovery, power generation and reuse system, including a cold compressor, a first heat exchanger, a buffer tank, an impeller, an induced draft fan, and a second heat exchanger through which a medium passes in sequence. The medium outlet of the second heat exchanger is connected to the medium inlet of the cold compressor. A constant pressure valve through which the medium passes is also provided between the buffer tank and the impeller. A low-grade heat source for heat exchange with the medium flows in the second heat exchanger, and the rotating shaft of the impeller is connected to the rotating shaft of the generator.

[0005] When the present invention is in use, the low-grade heat source enters the second heat exchanger, exchanges heat with the medium, so that the medium absorbs the heat of the low-grade heat source, and then enters the cold compressor, and is compressed to form a high-temperature and high-pressure medium. The high-temperature and high-pressure medium transfers heat to the heat-carrying fluid in the first heat exchanger to form a high-pressure and low-temperature medium, and then enters the buffer tank for storage. When the medium pressure in the buffer tank reaches the set value of the constant pressure valve, the constant pressure valve opens, and the medium enters the impeller through the constant pressure valve, driving the impeller to rotate. The rotation of the impeller drives the generator shaft to rotate to generate electricity. The medium after power generation is a low-pressure and low-temperature medium. Under the action of the induced draft fan, it is sent to the second heat exchanger and enters the next cycle, thereby making full use of the heat of the low-grade heat source and achieving the purpose of recovering waste heat.

[0006] Preferably, the generator is connected to the electric energy storage continuous heating equipment through a controller, the electric energy storage continuous heating equipment is provided with a fluid heating pipe, the heat-carrying fluid outlet of the first heat exchanger is connected to the fluid heating pipe, the fluid outlet of the electric energy storage continuous heating equipment is connected to the industrial equipment, and the fluid outlet of the industrial equipment is connected to the fluid inlet of the first heat exchanger through a fluid pipe.

[0007] When this preferred solution is in use, the electricity generated by the generator is transmitted to the electric energy storage continuous heating device through the controller, and the electric energy is converted into thermal energy in the electric energy storage continuous heating device. The molten salt energy storage material is heated by a ring-shaped electric wire heating device, and is absorbed and stored by the molten salt energy storage material to form a constant temperature heat source. In the first heat exchanger, the heat-carrying fluid that exchanges heat with the high-temperature and high-pressure medium exchanges heat with the molten salt energy storage material and is transmitted to the industrial equipment for use. After being used by the industrial equipment, the heat-carrying fluid returns to the first heat exchanger for circulating heat exchange again, thereby forming a second closed system. This system greatly improves the COP of the compressor through heat exchange and power generation and energy storage reuse.

[0008] Preferably, two generators are provided, and the rotating shafts of the two generators are respectively connected to the two ends of the rotating shaft of the impeller. This preferred solution maintains the balance of the impeller by providing two generators.

[0009] Preferably, the impeller comprises an impeller axially connected to a volute, and a feed inlet of the volute extends along a tangential direction of the impeller.

[0010] This preferred solution enables the medium to vertically impact one side of the V-groove of the impeller along the tangential direction through the arrangement of the volute feed port and the impeller, thereby reducing the decomposition of the medium thrust, increasing the driving torque, and improving the power generation efficiency.

[0011] Preferably, the V-grooves on the impeller are evenly arranged in the circumferential direction, and the side of the V-grooves impacted by the medium is on the impeller circular diameter and is symmetrically arranged with respect to the impeller rotation axis.

[0012] Preferably, the impeller is further provided with a weight-reducing hole between the V-groove and the impeller shaft. This preferred solution reduces the weight of the impeller itself by providing the weight-reducing hole, thereby reducing the inertia of the impeller.

[0013] The beneficial effects of the present invention are as follows: the low-grade heat source enters the second heat exchanger, exchanges heat with the medium, and the medium absorbs the heat of the low-grade heat source, and then enters the cold compressor, and is compressed to form a high-temperature and high-pressure medium. The high-temperature and high-pressure medium transfers heat to the heat-carrying fluid in the first heat exchanger to form a high-pressure and low-temperature medium, and then enters the buffer tank for storage. When the medium pressure in the buffer tank reaches the set value of the constant pressure valve, it enters the impeller through the constant pressure valve, drives the impeller to rotate, and the rotation of the impeller drives the generator shaft to rotate to generate electricity. The medium after power generation becomes a low-pressure and low-temperature medium, which is sent to the second heat exchanger under the action of the induced draft fan to form a high-pressure and low-temperature medium. The process forms a cycle to achieve the purpose of low-grade waste heat recovery and reduce thermal pollution. The electricity generated by the generator is transmitted to the electric energy storage continuous heating equipment through the controller, and the electric energy is converted into thermal energy in the electric heating equipment, and is absorbed and stored by the hot molten salt energy storage material to form a constant temperature heat source. In the first heat exchanger, the heat-carrying fluid that exchanges heat with the high-temperature and high-pressure medium exchanges heat with the hot molten salt energy storage material and is transmitted to the industrial equipment for use. After being used by the industrial equipment, the heat-carrying fluid returns to the first heat exchanger for circulating heat exchange again, thereby forming a second closed system. The medium of this system is reused after heat exchange and power generation, which greatly improves the COP of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of medium flow; Figure 3 is a schematic diagram of current flow; Figure 4 is a schematic diagram of the flow of heat-carrying fluid; Figure 5 It is a schematic diagram of the main view of the impeller; Figure 6 is a schematic diagram of the side view of the impeller; Figure 7 is a schematic diagram of the impeller; As shown in the figure: 1. volute, 2. impeller, 3. impeller shaft, 4. feed inlet of impeller, 5. discharge outlet of impeller, 6. base of impeller, 7. buffer bin, 11. compressor, 12. first heat exchanger, 13. impeller, 14. low-grade heat source, 15. generator, 16. induced draft fan, 17. second heat exchanger, 18. electric energy storage continuous heating equipment, 19. controller, 20. buffer tank, 21. constant pressure valve. DETAILED DESCRIPTION

[0015] In order to clearly illustrate the technical features of this solution, this solution is described below through a specific implementation method.

[0016] See attached Figure 1-7The present invention provides a fully enclosed low-grade waste heat recovery power generation reuse system, comprising a cold compressor 11, a first heat exchanger 12, a buffer tank 20, an impeller 13, an induced draft fan 16, and a second heat exchanger 17 through which a medium passes in sequence. The medium outlet of the second heat exchanger 17 is connected to the medium inlet of the cold compressor 11. A constant pressure valve 21 through which the medium passes is also provided between the buffer tank 20 and the impeller 13. A low-grade heat source for exchanging heat with the medium flows in the second heat exchanger 17.

[0017] The rotating shaft of the impeller 13 is connected to the rotating shaft of the generator. Two generators are provided, and the rotating shafts of the two generators are respectively connected to the two ends of the impeller rotating shaft 3.

[0018] The electricity generated by the generator is transmitted to the electric energy storage continuous heating device 18 through the controller 19. The electric energy storage continuous heating device is provided with a fluid heating pipeline. The fluid outlet of the first heat exchanger 12 is connected to the fluid heating pipeline in the electric energy storage continuous heating device 18. The fluid outlet of the electric energy storage continuous heating device 18 is connected to the industrial equipment. The fluid outlet of the industrial equipment is connected to the fluid inlet of the first heat exchanger 12 through the fluid pipeline.

[0019] The electric energy storage continuous heating equipment is the applicant's prior art. The outer tube of the electric energy storage continuous heating is provided with a hot molten salt energy storage material located between the outer tube and the fluid heating pipeline. An annular electric conductor is wound on the outer tube. Current is passed through the annular electric conductor. Eddy currents are generated during the flow of current along the annular electric conductor, and the molten salt energy storage material is heated through the outer tube. The annular electric conductor is connected to the controller.

[0020] The impeller 13 includes an impeller axially connected to the volute 1. The gap between the impeller and the volute is very small to prevent the high-pressure medium from entering the buffer bin 7 through the gap without doing work. The feed port of the volute 1 extends along the tangential direction of the impeller. The volute 1 is provided with a buffer bin 7 located below the impeller, and the buffer bin 7 is provided with a medium outlet.

[0021] The V-grooves on the impeller are evenly arranged along the circumferential direction, the surface of the V-grooves impacted by the medium is on the impeller circular diameter and is symmetrically arranged with respect to the impeller rotating axis. The impeller is also provided with a weight reduction hole located between the V-grooves and the impeller rotating axis 3.

[0022] The first heat exchanger and the second heat exchanger are both existing technologies. The first heat exchanger and the second heat exchanger both include a tube side and a shell side for heat exchange. The compressor 11 is existing technology, and the controller 19 is designed by itself according to the system process and the performance of the hot molten salt.

[0023] When the present invention is in use, the low-grade heat source 14 enters the second heat exchanger, exchanges heat with the medium, and the medium absorbs the heat of the low-grade heat source 14, and then enters the cold compressor 11, and is compressed to form a high-temperature and high-pressure medium. The high-temperature and high-pressure medium transfers heat to the heat-carrying fluid in the first heat exchanger 12 to form a high-pressure and low-temperature medium, and then enters the buffer tank 20 for storage. When the medium pressure in the buffer tank 20 reaches the set value of the constant pressure valve 21, the constant pressure valve opens, and the medium enters the impeller 13 through the constant pressure valve 21, driving the impeller to rotate. The rotation of the impeller drives the generator shaft to rotate to generate electricity. The medium after power generation is a low-pressure and low-temperature medium. Under the action of the induced draft fan, it is sent to the second heat exchanger to absorb the heat of the low-grade heat source, forming a cycle, thereby reducing thermal pollution; The electricity generated by the generator is transmitted to the electric energy storage continuous heating device 18 through the controller 19, and the electric energy is converted into thermal energy in the electric heating device, and is absorbed and stored by the hot molten salt energy storage material to form a constant temperature heat source. In the first heat exchanger 12, the heat-carrying fluid that exchanges heat with the high-temperature and high-pressure medium exchanges heat with the hot molten salt energy storage material, and its temperature is raised to the industrial heat utilization requirement, and then it is transmitted to the industrial equipment for use. After being used by the industrial equipment, the heat-carrying fluid returns to the first heat exchanger 12 for circulating heat exchange again, thereby forming a second closed system. This system greatly improves the COP of the compressor 11 through heat exchange and power generation and energy storage reuse.

[0024] Of course, the above description is not limited to the above examples. Technical features not described in the present invention can be achieved by or by using existing technologies, which will not be repeated here. The above embodiments and drawings are only used to illustrate the technical scheme of the present invention and are not limitations of the present invention. The present invention is described in detail with reference to the preferred implementation methods. Ordinary technicians in this field should understand that changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention do not depart from the purpose of the present invention, and should also fall within the scope of protection of the claims of the present invention.

Claims

1. A fully enclosed low-grade waste heat recovery power generation and reuse system, characterized by: The invention comprises a cold compressor (11), a first heat exchanger (12), a buffer tank (20), an impeller (13), an induced draft fan (16), and a second heat exchanger (17), through which a medium passes in sequence; a medium outlet of the second heat exchanger (17) is connected to a medium inlet of the cold compressor (11); a constant pressure valve (21) through which the medium passes is also provided between the buffer tank (20) and the impeller (13); a low-grade heat source for heat exchange with the medium flows in the second heat exchanger; and a rotating shaft of the impeller (13) is connected to a rotating shaft of a generator.

2. The fully enclosed low-grade waste heat recovery power generation and reuse system according to claim 1 is characterized in that: The generator is connected to the electric energy storage continuous heating device (18) via a controller (19); a fluid heating pipeline is provided in the electric energy storage continuous heating device; a heat-carrying fluid outlet of the first heat exchanger (12) is connected to the fluid heating pipeline; a fluid outlet of the electric energy storage continuous heating device (18) is connected to the industrial equipment; and a fluid outlet of the industrial equipment is connected to a fluid inlet of the first heat exchanger (12) via a fluid pipeline.

3. The fully enclosed low-grade waste heat recovery power generation and reuse system according to claim 1 is characterized in that: The generators are provided with two, and the rotating shafts of the two generators are respectively connected to the two ends of the impeller rotating shaft (3).

4. The fully enclosed low-grade waste heat recovery power generation and reuse system according to claim 1 is characterized in that: The impeller (13) comprises an impeller axially connected to a volute (1); the feed inlet of the volute (1) extends in a turbine tangential direction.

5. The fully enclosed low-grade waste heat recovery power generation and reuse system according to claim 4 is characterized in that: The V-grooves on the impeller are evenly arranged along the circumferential direction, and the side of the V-grooves impacted by the medium is on the impeller circular diameter and is symmetrically arranged with respect to the impeller rotation axis.

6. The fully enclosed low-grade waste heat recovery power generation and reuse system according to claim 5 is characterized in that: The impeller is also provided with a weight-reducing hole located between the V-groove and the impeller shaft (3).

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