Heat pump drying system oriented to heat and moisture decoupling

Abstract

The application discloses a heat pump drying system for heat and humidity decoupling, and belongs to the technical field of heat pump drying, which solves the problems of heat and humidity mismatch and heat and cold mismatch in the prior art. The heat pump drying system mainly comprises a power generation unit and a heat pump circulation unit, wherein the power generation unit is connected with the heat pump circulation unit; the power generation unit comprises an evaporator, a turbine, a condenser and a liquid pump, and the evaporator, the turbine, the condenser and the liquid pump are sequentially connected; the condenser is connected with a condensing dehumidifier, and the condensing dehumidifier is connected with a pre-cooler; the pre-cooler is connected with the outside; the heat pump circulation unit comprises a compressor, a circulating condenser, an expansion valve and a compressor connection; the circulating condenser is connected with a drying unit, the drying unit is connected with the condensing dehumidifier and the pre-cooler respectively, the pre-cooler is connected with a circulating evaporator, and the condensing dehumidifier is connected with the circulating condenser. The application can realize gradient and efficient utilization of the cold energy of liquefied natural gas, realize heat and humidity decoupling, and improve drying efficiency.

Description

Technical Field

[0001] This invention relates to the field of heat pump drying technology, and more particularly to a heat pump drying system for heat and humidity decoupling. Background Technology

[0002] Currently, my country has a strong demand for natural gas. The existing method of LNG transportation is by sea, with LNG receiving terminals typically built in coastal cities to handle the receipt, storage, and transportation of LNG. LNG vaporizes by absorbing ambient heat for use, resulting in a significant waste of cooling capacity. The primary utilization method currently is ORC (Organic Regenerative Thermal Cryogenic) power generation systems, which use the cooling capacity of LNG to generate electricity. Furthermore, coastal cities also have a strong demand for drying, but due to their proximity to the sea, they experience high humidity, which is unfavorable for the operation of open-loop heat pump drying systems. While closed-loop heat pump drying systems are not affected by environmental factors, as exemplified by the closed-loop heat pump condensation heat recovery drying system disclosed in application CN108679996A, a heat and humidity mismatch exists during the drying process. This mismatch between heat and cooling capacity in closed-loop heat pump drying systems limits their drying performance, sometimes even preventing them from completing the drying task. Even in ORC power generation systems utilizing LNG cooling energy, some low-grade cooling capacity remains unutilized, resulting in wasted cooling capacity. Summary of the Invention

[0003] The purpose of this invention is to provide a heat pump drying system for heat and humidity decoupling, which can achieve efficient and gradient utilization of cooling capacity, and the closed heat pump drying system has high drying efficiency due to heat and humidity decoupling.

[0004] This invention is achieved through the following technical solution:

[0005] A heat pump drying system for heat and humidity decoupling includes a power generation unit and a heat pump circulation unit, with the power generation unit connected to the heat pump circulation unit. The power generation unit includes an evaporator connected to a turbine, which in turn is connected to a condenser, which is connected to a liquid pump. The condenser is connected to a condensing dehumidifier, which is connected to a precooler. The precooler is connected to an external source. The heat pump circulation unit includes a compressor and a circulating condenser, with the compressor connected to the circulating condenser, the circulating condenser connected to an expansion valve, and the expansion valve connected to a circulating evaporator. The circulating evaporator is connected to the circulating condenser, which is connected to a drying unit. The drying unit is connected to both the condensing dehumidifier and the precooler, with the precooler connected to the circulating evaporator. The condensing dehumidifier is connected between the circulating condenser and the circulating evaporator.

[0006] Furthermore, the evaporator is equipped with a seawater inlet pipeline and a seawater outlet pipeline.

[0007] Furthermore, the turbine is connected to the compressor.

[0008] Furthermore, the drying unit includes drying chamber I and drying chamber II. A circulating condenser is connected to drying chamber I and drying chamber II. Drying chamber I is connected to a precooler, the precooler is connected to a circulating evaporator, the circulating evaporator is connected to a circulating condenser, drying chamber II is connected to a condensing dehumidifier, and the condensing dehumidifier is connected to the circulating condenser.

[0009] Furthermore, the evaporator includes evaporator I, evaporator II, and evaporator III; the condenser includes condenser I, condenser II, and condenser III; the turbine includes turbine I, turbine II, and turbine III; the liquid pump includes liquid pump I, liquid pump II, and liquid pump III; evaporator I is connected to turbine I, turbine I is connected to condenser I, condenser I is connected to liquid pump I, and liquid pump I is connected to evaporator I; evaporator II is connected to turbine II, turbine II is connected to condenser II, condenser II is connected to liquid pump II, and liquid pump II is connected to evaporator II; evaporator III is connected to turbine III, turbine III is connected to condenser III, condenser III is connected to liquid pump III, and liquid pump III is connected to evaporator III.

[0010] Furthermore, the condenser I, condenser II, and condenser III are connected in sequence and finally connected to the condenser dehumidifier.

[0011] Furthermore, the working fluid used in the heat pump cycle unit is R134A; the working fluid used in the power generation unit is R290.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] 1. This invention utilizes the cooling capacity of LNG to provide the cooling capacity required for condensation and dehumidification of the humid air in the condenser dehumidifier of the circulating drying unit, thereby improving the cooling capacity utilization efficiency and dehumidification efficiency; and utilizes the cooling capacity of LNG as the cold source for the sensible heat treatment of the precooler to cool the humid air at the outlet of the drying chamber to the dew point temperature. The cooling capacity in the evaporator of the heat pump cycle unit will only need to handle the latent heat of the humid air and will be used entirely for condensation and dehumidification, thereby improving the dehumidification efficiency of the evaporator.

[0014] 2. This invention utilizes a multi-stage condenser, a condensation dehumidifier, and a precooler connected in sequence to form a gradient temperature rise of LNG from a low-temperature liquid state to a normal-temperature gaseous state, thereby realizing the gradient and efficient utilization of LNG's cooling capacity and effectively reducing heat exchange temperature difference and heat loss.

[0015] 3. This invention utilizes a power generation unit to provide power for the operation of the compressor in the heat pump cycle unit, achieving self-sufficiency in the power demand of the entire coupled system; it utilizes high-grade refrigeration capacity for ORC power generation, and then utilizes low-grade LNG refrigeration capacity to provide refrigeration capacity for the closed-loop heat pump drying system, which can solve the problem of heat and humidity mismatch in the existing heat pump drying system, achieve heat and humidity decoupling, and improve drying performance.

[0016] 4. Compared with traditional heat pump drying systems, the drying unit of this invention has two drying chambers and only requires one heat pump circulation unit and one condenser dehumidifier. Compared with two complete closed-loop heat pump drying systems, the structure is simpler. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention.

[0018] In the diagram: 1. Evaporator I; 2. Liquid pump I; 3. Condenser I; 4. Turbine I; 5. Evaporator II; 6. Liquid pump II; 7. Condenser II; 8. Turbine II; 9. Evaporator III; 10. Liquid pump III; 11. Condenser III; 12. Turbine III; 13. Compressor; 14. Circulating condenser; 15. Expansion valve; 16. Circulating evaporator; 17. Drying chamber I; 18. Drying chamber II; 19. Condensation dehumidifier; 20. Precooler. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments in this application, other similar embodiments obtained by those skilled in the art without creative effort should all fall within the scope of protection of this application. Furthermore, directional terms mentioned in the following embodiments, such as "up," "down," "left," and "right," are only for reference to the directions in the accompanying drawings; therefore, the directional terms used are for illustrative purposes and not for limiting the invention.

[0020] The present invention will now be further described in conjunction with the accompanying drawings.

[0021] Example 1: A heat pump drying system for heat and humidity decoupling, such as Figure 1As shown, the system includes a power generation unit and a heat pump cycle unit. The power generation unit includes an evaporator connected to a turbine, which in turn is connected to a condenser connected to the turbine. The condenser is connected to a liquid pump. The condenser is connected to a condensing dehumidifier 19, which is connected to a precooler 20. The precooler 20 is connected to an external source. The heat pump cycle unit includes a compressor 13 and a circulating condenser 14. The first outlet of the compressor 13 is connected to the first inlet of the circulating condenser 14, and the first outlet of the circulating condenser 14 is connected to the inlet of an expansion valve 15. The outlet of the expansion valve 15 is connected to a circulating evaporator. The first inlet of the circulating evaporator 16 is connected to the first outlet of the evaporator 16, which is connected to the first inlet of the compressor 13. The second outlet of the circulating evaporator 16 is connected to the second inlet of the circulating condenser 14. The second outlet of the circulating condenser 14 is connected to a drying unit. The drying unit is connected to a condenser dehumidifier 19 and a precooler 20. The first outlet of the precooler 20 is connected to the second inlet of the circulating evaporator 16. The second outlet of the condenser dehumidifier 19 is connected between the second inlet of the circulating condenser 14 and the second outlet of the circulating evaporator 16, and is connected to the second inlet of the circulating evaporator 16.

[0022] The cooling capacity of LNG is used to provide the cooling capacity required for condensation and dehumidification of the humid air in the condenser dehumidifier 19 of the circulating drying unit, thereby improving the cooling capacity utilization efficiency and dehumidification efficiency. The cooling capacity of LNG is used as the cold source for the sensible heat treatment of the precooler 20 of the circulating drying unit, cooling the humid air at the outlet of the drying chamber to the dew point temperature. In this way, the cooling capacity in the evaporator of the heat pump cycle unit will only need to handle the latent heat of the humid air and will be used entirely for condensation and dehumidification, which will greatly improve the dehumidification efficiency of the evaporator.

[0023] The evaporator includes evaporator I1, evaporator II5, and evaporator III9; the condenser includes condenser I3, condenser II7, and condenser III11; the turbine includes turbine I4, turbine II8, and turbine III12; the liquid pump includes liquid pump I2, liquid pump II6, and liquid pump III10; the first outlet of evaporator I1 is connected to the inlet of turbine I4, the outlet of turbine I4 is connected to the first inlet of condenser I3, the first outlet of condenser I3 is connected to the inlet of liquid pump I2, and the outlet of liquid pump I2 is connected to the first inlet of evaporator I1. The outlets of the evaporator II5 and III are connected as follows: the first outlet of evaporator II5 is connected to the inlet of turbine II8, the outlet of turbine II8 is connected to the first inlet of condenser II7, the first outlet of condenser II7 is connected to the inlet of liquid pump II6, and the outlet of liquid pump II6 is connected to the first inlet of evaporator II5; the first outlet of evaporator III9 is ​​connected to the inlet of turbine III12, the outlet of turbine III12 is connected to the first inlet of condenser III11, the outlet of condenser III11 is connected to the inlet of liquid pump III10, and the outlet of liquid pump III10 is connected to the first inlet of evaporator III9. Utilizing the high-grade LNG cooling capacity for ORC power generation and then using the low-grade LNG cooling capacity to provide cooling for the closed-loop heat pump drying system can solve the problem of heat and humidity mismatch in the closed-loop heat pump drying system, achieving heat and humidity decoupling and significantly improving drying performance.

[0024] Example 2: A heat pump drying system for heat and humidity decoupling, wherein the evaporator is provided with a seawater inlet pipeline and a seawater outlet pipeline, and the seawater is connected to the second inlet of evaporator I1, evaporator II5 and evaporator III9 respectively, and the cooled seawater is discharged into the sea through the second outlet of evaporator I1, evaporator II5 and evaporator III9.

[0025] The turbine is connected to the compressor 13; turbine I 4, turbine II 8 and turbine III 12 can provide power for the drive of the compressor 13; the power generation unit provides power for the operation of the compressor 13 in the heat pump cycle unit, so as to achieve self-sufficiency of power demand for the entire coupled system.

[0026] The drying unit includes drying chamber I 17 and drying chamber II 18. The second outlet of the circulating condenser 14 is connected to the inlet of drying chamber I 17 and simultaneously to the inlet of drying chamber II 18. The outlet of drying chamber I 17 is connected to the first inlet of precooler 20. The first outlet of precooler 20 is connected to the second inlet of circulating evaporator 16. The second outlet of circulating evaporator 16 is connected to the second inlet of circulating condenser 14. The outlet of drying chamber II 18 is connected to the first inlet of condensing dehumidifier 19. The first outlet of condensing dehumidifier 19 is connected to the second hot port of circulating condenser 14. This invention provides two drying chambers and requires only one heat pump circulation unit and one condensing dehumidifier 19, resulting in a simpler structure.

[0027] The condensers I3, II7, and III11 are connected sequentially and finally connected to the condenser dehumidifier 19. The second inlet of condenser I3 is connected to the LNG source line, the second outlet of condenser I3 is connected to the second inlet of condenser II7, the second outlet of condenser II7 is connected to the second inlet of condenser III11, the second outlet of condenser III11 is connected to the second inlet of the condenser dehumidifier 19, the second outlet of the condenser dehumidifier 19 is connected to the second inlet of the precooler 20, and the second outlet of the precooler 20 is connected to an external natural gas user. The sequential connection of the multi-stage condensers, condenser dehumidifier 19, and precooler 20 creates a gradient temperature rise of LNG from a low-temperature liquid state to a normal-temperature gaseous state, achieving a gradient and efficient utilization of LNG cooling capacity, and effectively reducing heat exchange temperature difference and heat loss. Other aspects are the same as in Example 1, except that the working fluid used in the heat pump cycle unit is R134A, and the working fluid used in the power generation unit is R290.

[0028] The cryogenic LNG first enters condenser I3, condenser II7, and condenser III11 in sequence to provide cooling for the condensation and liquefaction of the refrigerant. The LNG with most of its cooling capacity utilized then enters condenser dehumidifier 19 to provide cooling for the condensation and dehumidification of the humid air at the outlet of drying chamber II18. Finally, it enters precooler 20 to precool the humid air at the outlet of drying chamber II18, remove the sensible heat of the humid air, and precool it to the dew point temperature. The vaporized LNG is then delivered to the gas user.

[0029] In the heat pump cycle unit, the high-temperature, high-pressure gaseous refrigerant at the outlet of compressor 13 enters the circulating condenser 14 to provide heat for the heating of the humid air at the outlet of the circulating evaporator 16 and the condenser dehumidifier 19. The high-pressure liquid refrigerant after condensation and liquefaction then enters the expansion valve 15 for throttling and pressure reduction. The low-temperature gas-liquid two-state refrigerant after cooling and pressure reduction then enters the circulating evaporator 16 to provide cooling for the condensation and liquefaction of the humid air at the outlet of the precooler 20. The low-pressure gaseous refrigerant after heating and vaporization finally enters the compressor 13 for expansion and work.

[0030] After absorbing heat from the refrigerant in the circulating evaporator 16 and reaching the rated drying temperature, the hot, dry air is first divided into two streams and enters drying chamber I 17 and drying chamber II 18 to convect and dehumidify with the material. The humid air from the outlet of drying chamber I 17 enters the precooler 20 for precooling. After absorbing the cold energy of LNG, the humid air, which has been reduced to the dew point temperature, enters the circulating evaporator 16 to absorb the cold energy of the refrigerant and undergoes condensation and dehumidification. The dehumidified air is then sent to the circulating condenser 14. The humid air from the outlet of drying chamber II 18 enters the condensation dehumidifier 19 to absorb the cold energy of LNG and undergoes condensation and dehumidification. The dehumidified air and the humid air from the outlet of the circulating evaporator 16 are sent together to the circulating condenser 14 to absorb heat from the refrigerant.

[0031] The present invention has been described in detail above. The above description is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of this application should still fall within the scope of the present invention.

Claims

1. A heat pump drying system for heat and humidity decoupling, characterized in that: The system includes a power generation unit and a heat pump circulation unit. The power generation unit is connected to the heat pump circulation unit. The power generation unit includes an evaporator connected to a turbine, and the turbine is connected to a condenser. The condenser includes condenser I (3), condenser II (7), and condenser III (11), and is connected to a liquid pump. The condenser is connected to a condensing dehumidifier (19), and the condensing dehumidifier (19) is connected to a precooler (20). The precooler (20) is connected to the outside. The heat pump circulation unit includes a compressor (13) and a circulating condenser (14). The first outlet of the compressor (13) is connected to the first inlet of the circulating condenser (14), and the first outlet of the circulating condenser (14) is connected to the inlet of the expansion valve (15). The outlet of the expansion valve (15) is connected to the first inlet of the circulating evaporator (16), and the circulating evaporator (16) is connected to the first inlet of the circulating evaporator (16). The first outlet of the evaporator (16) is connected to the first inlet of the compressor (13); the second outlet of the circulating evaporator (16) is connected to the second inlet of the circulating condenser (14), the second outlet of the circulating condenser (14) is connected to a drying unit, the drying unit is connected to the condenser dehumidifier (19) and the precooler (20) respectively, the first outlet of the precooler (20) is connected to the second inlet of the circulating evaporator (16), and the second outlet of the condenser dehumidifier (19) is connected between the second inlet of the circulating condenser (14) and the second outlet of the circulating evaporator (16); the low temperature LNG first enters the condenser I (3), condenser II (7) and condenser III (11) in sequence to provide cooling capacity for the condensation and liquefaction of the refrigerant, the LNG whose cooling capacity is mostly utilized then enters the condenser dehumidifier (19), and finally enters the precooler (20).

2. The heat pump drying system for heat and humidity decoupling according to claim 1, characterized in that: The evaporator is equipped with a seawater inlet pipeline and a seawater outlet pipeline.

3. The heat pump drying system for heat and humidity decoupling according to claim 1, characterized in that: The turbine is connected to the compressor (13).

4. The heat pump drying system for heat and humidity decoupling according to claim 1, characterized in that: The drying unit includes drying chamber I (17) and drying chamber II (18). A circulating condenser (14) is connected to drying chamber I (17) and drying chamber II (18). Drying chamber I (17) is connected to precooler (20), and drying chamber II (18) is connected to condenser dehumidifier (19).

5. The heat pump drying system for heat and humidity decoupling according to claim 2, characterized in that: The evaporator includes evaporator I (1), evaporator II (5), and evaporator III (9); the turbine includes turbine I (4), turbine II (8), and turbine III (12); the liquid pump includes liquid pump I (2), liquid pump II (6), and liquid pump III (10); evaporator I (1) is connected to turbine I (4), turbine I (4) is connected to condenser I (3), condenser I (3) is connected to liquid pump I (2), and liquid pump I (2) is connected to evaporator I (9). (1) Connected; Evaporator II (5) is connected to turbine II (8), turbine II (8) is connected to condenser II (7), condenser II (7) is connected to liquid pump II (6), liquid pump II (6) is connected to evaporator II (5); Evaporator III (9) is connected to turbine III (12), turbine III (12) is connected to condenser III (11), condenser III (11) is connected to liquid pump III (10), liquid pump III (10) is connected to evaporator III (9).

6. The heat pump drying system for heat and humidity decoupling according to claim 5, characterized in that: The condenser I (3), condenser II (7) and condenser III (11) are connected in sequence and finally connected to the condenser dehumidifier (19).

7. The heat pump drying system for heat and humidity decoupling according to claim 1, characterized in that: The heat pump cycle unit uses R134A as the working fluid; the power generation unit uses R290 as the working fluid.

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