A quality integrated waste heat utilization system and waste heat utilization method

Abstract

The present invention discloses a mass-integrated waste heat utilization system and a waste heat utilization method, which relate to the technical field of waste heat utilization, and include: an organic Rankine cycle and a compression heat pump unit, wherein the organic Rankine cycle includes an intermediate heat exchanger, a working fluid pump, a first evaporator and a steam turbine which are connected in sequence, and the compression heat pump unit includes a second evaporator, a compressor and a condenser which are connected in sequence, the working fluid outlet of the steam turbine is connected to the working fluid inlet of the second evaporator, the working fluid outlet of the condenser is connected to the working fluid inlet of the intermediate heat exchanger, and the heat source inlets of the first evaporator and the second evaporator are both connected to a waste heat supply pipeline; in the present invention, the organic Rankine cycle and the compression heat pump unit are integrated together in a mass integration manner, and compared with the heat integration of multiple units, the energy utilization rate is improved, and the amount of working fluid is saved; in addition, the steam turbine can be used as an expansion valve, which can effectively increase the power generation of the system and reduce the investment cost.

Description

Technical Field

[0001] The present invention relates to the technical field of waste heat utilization, and in particular to a mass-integrated waste heat utilization system and a waste heat utilization method. Background Art

[0002] The existing waste heat recovery system is no longer limited to a single utilization method, but adopts a multi-generation system, that is, simultaneous power generation and quality improvement or power generation and refrigeration, or even trigeneration of quality improvement, power generation and refrigeration; the multi-generation system is one of the important forms of distributed energy systems. Due to its significant comprehensive benefits in energy consumption, economy and environment, it has received widespread attention and application at home and abroad in recent years.

[0003] Existing research on cogeneration systems mostly adopts the form of heat integration. Heat integration inevitably produces heat loss due to the use of heat exchange equipment for integration, resulting in low system energy conversion efficiency, which in turn causes the problem of low energy utilization.

[0004] Therefore, people are in urgent need of a quality integrated waste heat utilization system with high energy utilization rate. Summary of the invention

[0005] The purpose of the present invention is to provide a mass-integrated waste heat utilization system and a waste heat utilization method to solve the problems existing in the above-mentioned prior art, and to integrate the organic Rankine cycle and the compression heat pump unit in a mass-integrated manner to improve energy utilization.

[0006] To achieve the above-mentioned purpose, the present invention provides the following solution: The present invention provides a mass-integrated waste heat utilization system, including an organic Rankine cycle and a compression heat pump unit, the organic Rankine cycle includes an intermediate heat exchanger, a working fluid pump, a first evaporator and a steam turbine connected in sequence, the compression heat pump unit includes a second evaporator, a compressor and a condenser connected in sequence, the working fluid outlet of the steam turbine is connected to the working fluid inlet of the second evaporator, the working fluid outlet of the condenser is connected to the working fluid inlet of the intermediate heat exchanger, and the heat source inlets of the first evaporator and the second evaporator are both connected to the waste heat supply pipeline.

[0007] Preferably, the first evaporator and the second evaporator are arranged in series on the waste heat supply pipeline, and the first evaporator is located at the front end of the waste heat supply path of the second evaporator.

[0008] Preferably, a plurality of the first evaporators and the second evaporators are provided, and the plurality of the first evaporators and the plurality of the second evaporators are all arranged in series.

[0009] Preferably, the steam turbine is drivingly connected to a generator.

[0010] Preferably, the generator is electrically connected to a battery pack.

[0011] Preferably, the battery pack is connected to electrical equipment within the mass-integrated waste heat utilization system or external electrical equipment.

[0012] Preferably, the heat exchange medium passage of the condenser is connected to external heat-using equipment.

[0013] Preferably, the heat exchange medium passage of the intermediate heat exchanger is connected to external heat-using equipment.

[0014] Preferably, the mass-integrated waste heat utilization system also includes an auxiliary heat exchanger, which is arranged between the working fluid pump and the first evaporator, the working fluid inlet of the auxiliary heat exchanger is connected to the working fluid outlet of the working fluid pump, the working fluid outlet is connected to the working fluid inlet of the first evaporator, the heat exchange medium inlet of the auxiliary heat exchanger is connected to the working fluid outlet of the condenser, and the heat exchange medium outlet is connected to the working fluid inlet of the intermediate heat exchanger.

[0015] The present invention also provides a waste heat utilization method using the mass integrated waste heat utilization system, comprising the following steps:

[0016] S1: The working fluid is heated up after heat exchange with the waste heat medium in the first evaporator and then enters the steam turbine, and the steam turbine outputs mechanical energy;

[0017] S2: The working fluid is cooled and depressurized after passing through the steam turbine, and then enters the second evaporator to exchange heat with the waste heat medium, and then enters the compressor for compression and is supplied to the condenser;

[0018] S3: The working fluid exchanges heat with the heat exchange medium in the condenser, the heat is transferred to the heat exchange medium and output, and the working fluid temperature decreases;

[0019] S4: The working fluid flows from the condenser into the intermediate heat exchanger, exchanges heat with the heat exchange medium and changes from gas phase to liquid phase, and then is transported by the working fluid pump to the first evaporator to continue to exchange heat with the waste heat medium.

[0020] Compared with the prior art, the present invention mainly achieves the following technical effects:

[0021] The organic Rankine cycle and the compression heat pump unit are integrated together through mass integration, and the passages in the two units are connected. Compared with multi-unit heat integration, there is no need to set up heat exchange equipment between units for heat exchange, which avoids heat waste during heat exchange between units and improves energy utilization. At the same time, there is no need for multiple groups of working fluids, which saves the amount of working fluids. In addition, the steam turbine in the organic Rankine cycle can be used as the expansion valve of the compression heat pump unit, which reduces the setting of the expansion valve, effectively improves the power generation of the system, and reduces the investment cost. After the working fluid in the second evaporator is heated up, the power consumption of the subsequent compressor can be effectively reduced.

[0022] Compared with the prior art, other solutions of the present invention have achieved the following technical effects:

[0023] The cascade utilization of waste heat can make the heat of a single waste heat medium be more fully absorbed by the system, further improving energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 It is a system diagram of the mass integrated waste heat utilization system of the present invention;

[0026] Figure 2 A system diagram of a mass-integrated waste heat utilization system provided with an auxiliary heat exchanger according to the present invention;

[0027] Among them, 1. the first evaporator; 2. the steam turbine; 3. the second evaporator; 4. the compressor; 5. the condenser; 6. the intermediate heat exchanger; 7. the working fluid pump; 8. the auxiliary heat exchanger; 9. the waste heat supply pipeline. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The purpose of the present invention is to provide a mass-integrated waste heat utilization system and a waste heat utilization method to solve the problems existing in the prior art, and to integrate an organic Rankine cycle and a compression heat pump unit in a mass-integrated manner to improve energy utilization.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Please refer to Figure 1-Figure 2As shown, a quality integrated waste heat utilization system is provided, including an organic Rankine cycle and a compression heat pump unit, the organic Rankine cycle includes an intermediate heat exchanger 6, a working fluid pump 7, a first evaporator 1 and a steam turbine 2 connected in sequence, the compression heat pump unit includes a second evaporator 3, a compressor 4 and a condenser 5 connected in sequence, the working fluid outlet of the steam turbine 2 is connected to the working fluid inlet of the second evaporator 3, the working fluid outlet of the condenser 5 is connected to the working fluid inlet of the intermediate heat exchanger 6, the heat source inlets of the first evaporator 1 and the second evaporator 3 are both connected to the waste heat supply pipeline 9, and the organic Rankine cycle and the compression heat pump unit are connected in sequence. The two units are integrated together in a mass integration manner, and the passages in the two units are interconnected. Compared with multi-unit heat integration, there is no need to set heat exchange equipment between units for heat exchange, which avoids heat waste during heat exchange between units and improves energy utilization. At the same time, there is no need for multiple groups of working fluids, which saves the amount of working fluids. In addition, the steam turbine 2 in the organic Rankine cycle can be used as an expansion valve for the compression heat pump unit, which reduces the setting of the expansion valve and the energy consumption of the expansion valve, and can effectively increase the power generation of the system while reducing the investment cost. After the working fluid in the second evaporator 3 is heated up, the power consumption of the subsequent compressor 4 can be effectively reduced.

[0032] In order to make more effective use of the waste heat of the waste heat medium, the first evaporator 1 and the second evaporator 3 are arranged in series on the waste heat supply pipeline 9. The first evaporator 1 is located at the front end of the waste heat supply path of the second evaporator 3. The first evaporator 1 and the second evaporator 3 realize the step-by-step utilization of waste heat, which enables the heat of a single waste heat medium to be more fully absorbed by the system, thereby further improving the energy utilization rate.

[0033] In order to further improve the heat absorption rate of the waste heat medium, a plurality of first evaporators 1 and second evaporators 3 are provided, and the plurality of first evaporators 1 and the plurality of second evaporators 3 are arranged in series, that is, a plurality of first evaporators 1 are connected in series between the first evaporator 1 and the steam turbine 2, and a plurality of second evaporators 3 are connected in series between the steam turbine 2 and the compressor 4, and the waste heat medium in the waste heat supply pipeline 9 flows through the plurality of first evaporators 1 and the second evaporators 3 in sequence; the number of the first evaporator 1 and the second evaporator 3 to be provided should be determined according to the actual waste heat amount, and it should be ensured that the waste heat medium transfers its own heat energy to the system working fluid at the plurality of first evaporators 1 and the second evaporator 3.

[0034] The steam turbine 2 converts the energy of steam into mechanical energy for output when operating normally. In this embodiment, the steam turbine 2 is configured to be transmission-connected to a generator to convert the mechanical energy into common electrical energy.

[0035] The generator is electrically connected to the battery pack so that the converted electrical energy can be stored for use when needed.

[0036] Since some equipment will require energy when the overall system is in operation, a battery pack can be set up to connect with the electrical equipment in the mass integrated waste heat utilization system, and the generated electric energy will be supplied to the system first. The electrical equipment in the system includes the transmission equipment of various media, the compressor 4 and the working fluid pump 7. When the equipment needs to use AC power, the battery pack can output AC power supply through the inverter; of course, if a large amount of electric energy is generated, the excess electric energy can also be supplied to external electrical equipment.

[0037] The heat exchange medium passage of the condenser 5 is connected with the external heat-using equipment to achieve the purpose of improving the quality. The heat exchange medium after temperature displacement with the working medium is transported to the external heat-using equipment to make full use of the thermal energy.

[0038] Similarly, the heat exchange medium passage of the intermediate heat exchanger 6 is connected to external heat-using equipment, further improving the heat energy output of the system.

[0039] The heat exchange medium of the intermediate heat exchanger 6 and the condenser 5 can be cooling water or other quality-improving fluids such as R1233zd (E), R1224yd (Z), R601a, R245fa, etc.

[0040] The generation of electricity and the output of heat energy make this system a quality-enhancing cogeneration system.

[0041] The mass-integrated waste heat utilization system also includes an auxiliary heat exchanger 8, which is arranged between the working fluid pump 7 and the first evaporator 1. The working fluid inlet of the auxiliary heat exchanger 8 is connected with the working fluid outlet of the working fluid pump 7, and the working fluid outlet is connected with the working fluid inlet of the first evaporator 1. The heat exchange medium inlet of the auxiliary heat exchanger 8 is connected with the working fluid outlet of the condenser 5, and the heat exchange medium outlet is connected with the working fluid inlet of the intermediate heat exchanger 6. After the system runs stably, the low-temperature working fluid output by the working fluid pump 7 is used to preliminarily cool the working fluid flowing out of the condenser 5, and the working fluid after the preliminarily cooling enters the intermediate heat exchanger 6 for cooling, which can effectively reduce the load of the intermediate heat exchanger 6.

[0042] The working fluid and heat exchange medium in the auxiliary heat exchanger 8 can be switched arbitrarily, that is, the output working fluid of the condenser 5 can be used as both the working fluid and the heat exchange medium of the auxiliary heat exchanger 8 .

[0043] The present invention also provides a waste heat utilization method using the mass integrated waste heat utilization system, comprising the following steps:

[0044] S1: The low-temperature working fluid is heated up after heat exchange with the waste heat medium in the first evaporator 1 and enters the steam turbine 2. The steam turbine 2 uses the working fluid energy to output mechanical energy, and then converts the mechanical energy into electrical energy through the generator to complete power generation. The power generation is stored in the battery pack for use by the equipment in the system and external electrical equipment;

[0045] S2: The working fluid is cooled and decompressed after passing through the steam turbine 2, then enters the second evaporator 3 to exchange heat with the waste heat medium, and then enters the compressor 4 to be compressed and supplied to the condenser 5;

[0046] S3: The working fluid exchanges heat with the heat exchange medium in the condenser 5 to complete the quality improvement, the heat is replaced into the heat exchange medium and output, the working fluid temperature is reduced, and the heat exchange medium after heat exchange is supplied to the external heat-using equipment;

[0047] S4: The working fluid flows from the condenser 5 into the intermediate heat exchanger 6, exchanges heat with the heat exchange medium and changes from gas phase to liquid phase, meeting the requirements of subsequent entry into the working fluid pump 7, and then is transported by the working fluid pump 7 to the first evaporator 1 to continue to exchange heat with the waste heat medium. The heat exchange medium of the intermediate heat exchanger 6 is also supplied to external heat-using equipment.

[0048] When the auxiliary heat exchanger 8 is provided, in step S4 , after the working fluid flows out of the condenser 5 , it first exchanges heat with the working fluid output by the working fluid pump 7 in the auxiliary heat exchanger 8 , then flows into the intermediate heat exchanger 6 , and is then transported to the first evaporator 1 through the working fluid pump 7 .

[0049] Adaptive changes made according to actual needs are all within the protection scope of the present invention.

[0050] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numerals in the claims should not be regarded as limiting the claims involved.

[0051] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A mass-integrated waste heat utilization system, characterized in that: It comprises an organic Rankine cycle and a compression heat pump unit, wherein the organic Rankine cycle comprises an intermediate heat exchanger, a working fluid pump, a first evaporator and a steam turbine which are connected in sequence, and the compression heat pump unit comprises a second evaporator, a compressor and a condenser which are connected in sequence, the working fluid outlet of the steam turbine is connected to the working fluid inlet of the second evaporator, the working fluid outlet of the condenser is connected to the working fluid inlet of the intermediate heat exchanger, the heat source inlets of the first evaporator and the second evaporator are both connected to a waste heat supply pipeline, and the steam turbine is an expansion valve of the compression heat pump unit; the heat exchange medium passage of the condenser is connected to an external heat-using device; the heat exchange medium passage of the intermediate heat exchanger is connected to an external heat-using device; The mass-integrated waste heat utilization system also includes an auxiliary heat exchanger, which is arranged between the working fluid pump and the first evaporator, the working fluid inlet of the auxiliary heat exchanger is connected to the working fluid outlet of the working fluid pump, and the working fluid outlet is connected to the working fluid inlet of the first evaporator, the heat exchange medium inlet of the auxiliary heat exchanger is connected to the working fluid outlet of the condenser, and the heat exchange medium outlet is connected to the working fluid inlet of the intermediate heat exchanger.

2. The mass-integrated waste heat utilization system according to claim 1, characterized in that: The first evaporator and the second evaporator are arranged in series on the waste heat supply pipeline, and the first evaporator is located at the front end of the waste heat supply path of the second evaporator.

3. The mass-integrated waste heat utilization system according to claim 2, characterized in that: A plurality of the first evaporators and the second evaporators are provided, and the plurality of the first evaporators and the plurality of the second evaporators are all arranged in series.

4. The mass-integrated waste heat utilization system according to claim 1, characterized in that: The steam turbine is drivingly connected to the generator.

5. The mass-integrated waste heat utilization system according to claim 4, characterized in that: The generator is electrically connected to the battery pack.

6. The mass-integrated waste heat utilization system according to claim 5, characterized in that: The battery pack is connected to electrical equipment in the mass-integrated waste heat utilization system or external electrical equipment.

7. A method for utilizing waste heat, characterized in that: The mass-integrated waste heat utilization system according to any one of claims 1 to 6 is applied, comprising the following steps: S1: The working fluid is heated up after heat exchange with the waste heat medium in the first evaporator and then enters the steam turbine, and the steam turbine outputs mechanical energy; S2: The working fluid is cooled and depressurized after passing through the steam turbine, and then enters the second evaporator to exchange heat with the waste heat medium, and then enters the compressor for compression and is supplied to the condenser; S3: The working fluid exchanges heat with the heat exchange medium in the condenser, the heat is transferred to the heat exchange medium and output, and the working fluid temperature decreases; S4: The working fluid flows from the condenser into the intermediate heat exchanger, exchanges heat with the heat exchange medium and changes from gas phase to liquid phase, and then is transported by the working fluid pump to the first evaporator to continue to exchange heat with the waste heat medium.

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