A flue gas source absorption heat pump unit

Abstract

This invention provides a flue gas source absorption heat pump unit, including an absorption heat pump unit, a pressure isolation device, a flue gas heat exchanger, a pressure regulating device, and a refrigerant pump. A portion of the refrigerant water in the evaporator is pressurized to positive pressure by the refrigerant pump and then enters the flue gas heat exchanger, where it is heated to recover heat from the flue gas. The heated refrigerant water is then returned to the evaporator. The evaporator employs a cavity structure with an internal vacuum environment. After heat exchange with the flue gas, the refrigerant water flashes and releases heat in the evaporator. This released heat is recovered by the heat pump and transferred to the heat user. To ensure a vacuum environment on the evaporator side of the unit, this invention adopts a split structure, with the absorber and evaporator placed on a platform at a height of over 10m. This eliminates the need for heat exchange tubes in the evaporator, simplifying the heat exchange process, improving waste heat recovery efficiency, significantly reducing investment costs, and enriching the application scenarios of flue gas waste heat recovery systems.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery technology, and in particular to a flue gas source absorption heat pump unit. Background Technology

[0002] The invention patent with publication number CN106996571A discloses a deep waste heat recovery system and method for flue gas from a coal-fired hot water boiler. It uses an absorption heat pump to produce low-temperature intermediate water, which enters a flue gas-water heat exchanger to exchange heat with the flue gas. The heated intermediate water returns to the heat pump evaporator as a low-temperature heat source. The absorption heat pump uses the boiler outlet water as the driving heat source to extract heat from the intermediate water and transfer it to the heating network water. In this system, the intermediate water only plays the role of an intermediate medium to transfer heat. From the perspective of the waste heat recovery process, it involves a two-stage heat exchange of heat pump refrigerant water-intermediate water-flue gas, which is complex and has low heat exchange efficiency. The invention patent with publication number CN105944527A provides a direct contact flue gas waste heat deep recovery and pollution reduction device and method. It uses an absorption heat pump to produce low-temperature intermediate water. The intermediate water directly contacts the flue gas for heat exchange and temperature increase. The heated intermediate water is returned to the absorption heat pump as a low-temperature heat source. In this system, because the intermediate water is in direct contact with the flue gas, the water quality is highly corrosive, and the intermediate water pipeline has high material requirements. Therefore, the use of intermediate water as a heat exchange medium not only brings problems such as complex heat exchange process and low heat exchange efficiency, but also leads to high investment in system pipelines and reduces the economic efficiency of waste heat recovery.

[0003] It is evident that the common use of intermediate water as a heat exchange medium in flue gas waste heat recovery systems not only leads to complex piping systems and high investment costs, but also increases the heat exchange process in waste heat recovery, reduces heat exchange efficiency, and affects the system's economics. Summary of the Invention

[0004] The purpose of this invention is to provide a flue gas source absorption heat pump unit that utilizes the refrigerant water of the absorption heat pump to exchange heat with the flue gas.

[0005] This invention provides a flue gas source absorption heat pump unit, comprising an absorption heat pump unit and a flue gas heat exchanger connected to each other; the absorption heat pump unit is a split structure, comprising a generator, a condenser, an absorber, and an evaporator, the flue gas heat exchanger and the evaporator are connected to form a heat exchange loop, the absorber and the evaporator are mounted above the generator and the condenser, the evaporator is a cavity structure without heat exchange tubes, and the interior of the evaporator is a vacuum environment; the refrigerant water outlet of the evaporator is connected to the cold fluid inlet of the flue gas heat exchanger, a refrigerant pump is provided on the connecting pipe between the refrigerant water outlet of the evaporator and the cold fluid inlet of the flue gas heat exchanger, the cold fluid outlet of the flue gas heat exchanger is connected to the refrigerant water inlet of the evaporator, and the flue gas to be treated is connected to the hot fluid inlet of the flue gas heat exchanger.

[0006] Furthermore, the generator and the condenser are placed on the ground, while the absorber and the evaporator are fixed on an installation platform at a height greater than 10 meters above the ground.

[0007] Furthermore, it also includes a refrigerant water internal circulation pump, the inlet end of which is connected to the refrigerant water outlet end of the evaporator, and the outlet end of which is connected to the refrigerant water inlet end of the evaporator.

[0008] Furthermore, it includes a pressure regulating device, which is connected to the inlet end of the cold fluid for flue gas heat exchange.

[0009] Furthermore, it includes a first pressure-isolating device and a second pressure-isolating device. The refrigerant water outlet of the evaporator is connected to the inlet of the first pressure-isolating device, and the outlet of the first pressure-isolating device is connected to the cold fluid inlet of the flue gas heat exchanger. The cold fluid outlet of the flue gas heat exchanger is connected to the inlet of the second pressure-isolating device, and the outlet of the second pressure-isolating device is connected to the refrigerant water inlet of the evaporator.

[0010] Furthermore, a plurality of first pressure-isolating devices are provided on the connecting pipe between the refrigerant water outlet end of the evaporator and the cold fluid inlet end of the flue gas heat exchanger, and a plurality of second pressure-isolating devices are provided on the connecting pipe between the cold fluid outlet end of the flue gas heat exchanger and the refrigerant water inlet end of the evaporator.

[0011] Furthermore, the first pressure-isolating device and the second pressure-isolating device are completely identical, both including an inner cylinder and an outer cylinder. The inner cylinder is provided with a water inlet, and the outer cylinder is provided with a water outlet. The top of the inner cylinder is connected to the air inlet of the gas collecting box through an exhaust pipe, and the air extraction port of the gas collecting box is connected to a vacuum pump.

[0012] Furthermore, each of the exhaust pipes is equipped with an exhaust valve.

[0013] Furthermore, the absorption heat pump unit is driven by an external heat source, which is hot water, steam, or flue gas.

[0014] Furthermore, the flue gas includes, but is not limited to, flue gas from thermal power plants, boilers, and petrochemical plants.

[0015] The advantages of the technical solution of the present invention compared with the prior art are as follows: The technical solution uses the refrigerant water of the absorption heat pump unit to exchange heat with the flue gas. The absorber and evaporator are mounted above the generator and condenser, which ensures the isolation of the unit vacuum and the positive pressure water circuit of the flue gas heat exchanger. The evaporator is designed as a cavity structure without heat exchange tubes and with a vacuum environment inside. The heat exchange tubes of the evaporator are eliminated, so that the refrigerant water enters the low-pressure environment of the evaporator for flash evaporation and heat release after exchanging heat with the flue gas. This simplifies the heat exchange process, improves the waste heat recovery efficiency, and significantly reduces investment costs. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the device structure of Embodiment 1 of the present invention;

[0018] Figure 2 This is a schematic diagram of the device structure in Embodiment 2 of the present invention;

[0019] Figure 3 This is a schematic diagram of the device structure in Embodiment 3 of the present invention;

[0020] Figure 4 This is a schematic diagram of the device structure of Embodiment 4 of the present invention;

[0021] Figure 5 This is a schematic diagram of the device structure in Embodiment 5 of the present invention;

[0022] Explanation of reference numerals in the attached drawings: 1-generator, 2-condenser, 3-absorber, 4-evaporator, 401-refrigerant water outlet, 402-refrigerant water inlet, 5-flue gas heat exchanger, 6-refrigerant internal circulation pump, 7-pressure regulating device, 8-first pressure isolation device, 801-inner cylinder, 802-outer cylinder, 9-second pressure isolation device, 10-exhaust valve, 11-gas collection box, 12-vacuum pump. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] Example 1

[0027] like Figure 1 As shown, the present invention provides a flue gas source absorption heat pump unit, including an absorption heat pump unit and a flue gas heat exchanger 5 connected to each other; the absorption heat pump unit is a split structure, and the absorption heat pump unit includes a generator 1, a condenser 2, an absorber 3 and an evaporator 4, and the flue gas heat exchanger 5 and the evaporator 4 are connected to form a heat exchange circuit.

[0028] Generator 1 and condenser 2 are placed on the ground, while absorber 3 and evaporator 4 are fixed on an installation platform at a height greater than 10 meters above the ground. The refrigerant water outlet 401 of evaporator 4 is connected to the cold fluid inlet of flue gas heat exchanger 5, and the cold fluid outlet of flue gas heat exchanger 5 is connected to the refrigerant water inlet 402 of evaporator 4. The flue gas to be treated is connected to the hot fluid inlet of flue gas heat exchanger 5. During the heat exchange process, the refrigerant water in evaporator 4 flows out through the refrigerant water outlet 401 and is pumped by a refrigerant pump. After being compressed, the refrigerant water enters the flue gas heat exchanger 5 as a cold source through a one-way valve assembly, where it exchanges heat with the flue gas flowing through the heat exchanger 5. The heated refrigerant water returns to the evaporator 4, which is a cavity structure without heat exchange tubes and operates under a vacuum. The heated refrigerant water flashes and releases heat in the evaporator 4, and the released heat is recovered by the absorption heat pump unit and provided to the heat users. The flue gas to be treated enters the hot fluid side of the flue gas heat exchanger 5 as a heat source, cools down in the heat exchanger 5, and then flows out. The absorption heat pump unit is driven by an external heat source, which can be hot water, steam, or flue gas to be treated. The flue gas to be treated includes, but is not limited to, flue gas from thermal power plants, boilers, and petrochemical plants.

[0029] In this embodiment, the refrigerant water of the heat pump unit exchanges heat with the flue gas, eliminating the need for the heat exchange tubes of the evaporator 4 in the heat pump unit. This simplifies the heat exchange process, improves heat exchange efficiency, and reduces unit costs. Simultaneously, by placing the evaporator 4 and absorber 3 of the absorption heat pump unit on a platform at a height of 10 meters or more, the isolation between the unit vacuum and the positive pressure water circuit of the flue gas heat exchanger 5 is ensured, guaranteeing the normal and stable operation of the system.

[0030] Example 2

[0031] like Figure 2 As shown, compared with Embodiment 1, the technical solution of this embodiment differs in that it further includes a refrigerant water internal circulation pump 6. The inlet end of the refrigerant water internal circulation pump 6 is connected to the refrigerant water outlet end 401 of the evaporator 4, and the outlet end of the refrigerant water internal circulation pump 6 is connected to the refrigerant water inlet end 402 of the evaporator 4. The addition of the refrigerant water internal circulation pump 6 in this embodiment can reduce the flow rate of external refrigerant water circulation, thereby reducing system investment costs and operating energy consumption. The remaining technical features of this embodiment are exactly the same as those of Embodiment 1, and will not be repeated here.

[0032] Example 3

[0033] like Figure 3 As shown, the technical solution of this embodiment differs from that of Embodiment 2 in that it includes a pressure regulating device 7, which is connected to the inlet end of the cold fluid in the flue gas heat exchanger. The addition of the pressure regulating device 7 ensures that the inlet pressure of the cold fluid in the flue gas heat exchanger 5 remains stable. The remaining technical features of this embodiment are exactly the same as those of Embodiment 2, and will not be repeated here.

[0034] Example 4

[0035] like Figure 4 As shown, the technical solution of this embodiment differs from that of embodiment 3 in that it includes a first pressure-isolating device 8 and a second pressure-isolating device 9. The refrigerant water outlet 401 of the evaporator 4 is connected to the inlet of the first pressure-isolating device 8, and the outlet of the first pressure-isolating device 8 is connected to the cold fluid inlet of the flue gas heat exchanger 5. The cold fluid outlet of the flue gas heat exchanger 5 is connected to the inlet of the second pressure-isolating device 9, and the outlet of the second pressure-isolating device 9 is connected to the refrigerant water inlet 402 of the evaporator 4. The first pressure-isolating device 8 and the second pressure-isolating device 9 are completely identical, both including an inner cylinder 801 and an outer cylinder 802. The inner cylinder 801 is provided with a water inlet, and the outer cylinder 802 is provided with a water outlet. The top of the inner cylinder 801 is connected to the air inlet of the gas collecting box 11 through an exhaust pipe. The air extraction port of the gas collecting box 11 is connected to the vacuum pump 12, and an exhaust valve 10 is installed on the exhaust pipe. By adding a first pressure isolation device 8 and a second pressure isolation device 9, the vacuum inside the unit can be isolated from the positive pressure water circuit of the flue gas heat exchanger 5. At this time, the evaporator 4 and absorber 3 do not need to be placed on an installation platform of more than 10 meters, thereby improving the overall compactness of the system and reducing the space requirements.

[0036] Example 5

[0037] like Figure 5 As shown, the technical features that distinguish this embodiment from embodiment 4 are as follows: a plurality of first pressure isolation devices 8 are provided on the connecting pipe between the refrigerant water outlet end 401 of the evaporator 4 and the cold fluid inlet end of the flue gas heat exchanger 5, and a plurality of second pressure isolation devices 9 are provided on the connecting pipe between the cold fluid outlet end of the flue gas heat exchanger 5 and the refrigerant water inlet end 402 of the evaporator 4.

[0038] Both the first pressure-isolating device 8 and the second pressure-isolating device 9 adopt an N-level liquid seal structure, where N≥1.

[0039] In this embodiment, the first pressure isolation device 8 is divided into a first-level pressure isolation device, a second-level pressure isolation device, ..., an N-level pressure isolation device, a gas collection box 11, and a vacuum pump 12.

[0040] The M-level pressure relief device includes an inlet, an outlet, an inner cylinder 801, an outer cylinder 802, an exhaust port, and an exhaust valve 10. The inlet of the M-level pressure relief device is located on the inner cylinder 801, and the outlet is located on the outer cylinder 802. The exhaust port is connected to the inlet of the exhaust valve 10, and the outlet is connected to the inlet of the gas collection box 11. The exhaust port of the gas collection box 11 is connected to the inlet of the vacuum pump 12. Wherein, 1≤M≤N.

[0041] The refrigerant water flowing out of the valve group flows in through the inlet of the first-stage pressure isolation device, flows sequentially through the first-stage pressure isolation device...Nth-stage pressure isolation device, flows out through the outlet of the Nth-stage pressure isolation device, and enters the evaporator 4 of the absorption heat pump unit.

[0042] The second pressure-reducing device 9 is also divided into a primary pressure-reducing device, a secondary pressure-reducing device, and so on up to an N-stage pressure-reducing device. The second pressure-reducing device 9 is installed on the connecting pipe between the cold fluid outlet end of the flue gas heat exchanger 5 and the refrigerant water inlet end 402 of the evaporator 4. The second pressure-reducing device 9 is the same as the first pressure-reducing device 8, and will not be described again here.

[0043] The pressure isolation device in this embodiment adopts a multi-stage liquid seal method, which can effectively isolate atmospheric pressure and vacuum, ensure the vacuum environment for normal operation of the unit, and guarantee the reliability and stability of system operation.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flue gas source absorption heat pump unit, characterized in that, The system includes an interconnected absorption heat pump unit and a flue gas heat exchanger. The absorption heat pump unit is a split structure, comprising a generator, condenser, absorber, and evaporator. The flue gas heat exchanger and the evaporator are connected to form a heat exchange loop. The absorber and the evaporator are mounted above the generator and condenser. The evaporator is a cavity structure without heat exchange tubes, and its interior is a vacuum environment. The refrigerant water outlet of the evaporator is connected to the cold fluid inlet of the flue gas heat exchanger. A refrigerant pump is installed on the connecting pipe between the refrigerant water outlet of the evaporator and the cold fluid inlet of the flue gas heat exchanger. The cold fluid outlet of the flue gas heat exchanger is connected to the refrigerant water inlet of the evaporator. The flue gas to be treated is connected to the hot fluid inlet of the flue gas heat exchanger. The generator and the condenser are placed on the ground, while the absorber and the evaporator are fixed on an installation platform at a height greater than 10 meters above the ground. The refrigerant water in the evaporator is pressurized to positive pressure by the refrigerant pump and then enters the flue gas heat exchanger. It directly exchanges heat with the flue gas to be treated and returns to the evaporator after heating. The heated refrigerant water flashes and releases heat in the vacuum environment of the evaporator, and the released heat is recovered by the absorption heat pump unit.

2. The flue gas source absorption heat pump unit according to claim 1, characterized in that, It also includes a refrigerant water internal circulation pump, the inlet end of which is connected to the refrigerant water outlet end of the evaporator, and the outlet end of which is connected to the refrigerant water inlet end of the evaporator.

3. The flue gas source absorption heat pump unit according to claim 2, characterized in that, It includes a pressure regulating device, which is connected to the inlet end of the cold fluid for flue gas heat exchange.

4. The flue gas source absorption heat pump unit according to claim 1, characterized in that, It includes a first pressure-isolating device and a second pressure-isolating device. The refrigerant water outlet of the evaporator is connected to the inlet of the first pressure-isolating device, and the outlet of the first pressure-isolating device is connected to the cold fluid inlet of the flue gas heat exchanger. The cold fluid outlet of the flue gas heat exchanger is connected to the inlet of the second pressure-isolating device, and the outlet of the second pressure-isolating device is connected to the refrigerant water inlet of the evaporator.

5. The flue gas source absorption heat pump unit according to claim 1, characterized in that, Multiple first pressure-isolation devices are installed on the connecting pipe between the refrigerant water outlet of the evaporator and the cold fluid inlet of the flue gas heat exchanger, and multiple second pressure-isolation devices are installed on the connecting pipe between the cold fluid outlet of the flue gas heat exchanger and the refrigerant water inlet of the evaporator.

6. The flue gas source absorption heat pump unit according to claim 4 or 5, characterized in that, The first pressure-isolating device and the second pressure-isolating device are exactly the same, both including an inner cylinder and an outer cylinder. The inner cylinder is provided with a water inlet, and the outer cylinder is provided with a water outlet. The top of the inner cylinder is connected to the air inlet of the gas collection box through an exhaust pipe, and the air extraction port of the gas collection box is connected to a vacuum pump.

7. The flue gas source absorption heat pump unit according to claim 6, characterized in that, Each of the exhaust pipes is equipped with an exhaust valve.

8. The flue gas source absorption heat pump unit according to claim 1, characterized in that, The absorption heat pump unit is driven by an external heat source, which is hot water, steam, or flue gas.

9. The flue gas source absorption heat pump unit according to claim 8, characterized in that, The flue gas includes one of the following: flue gas from thermal power plants, boiler flue gas, and industrial flue gas from petrochemical plants.

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