Heat pump direct outlet water vapor generating system

Abstract

The utility model discloses a heat pump direct outlet water vapor generating system which comprises a heat pump assembly, a water supply assembly and a vapor generator, a low-temperature waste heat source exchanges heat with a condensed refrigerant, so that the refrigerant is supercooled, and the refrigerating capacity of a heat pump system is increased; then the refrigerant is evaporated and exchanges heat with the refrigerant, the evaporation temperature of the heat pump system is increased, and the comprehensive energy efficiency of the heat pump system is improved; the steam generator is a shell and tube heat exchanger, tube plates used for fixing heat exchange tube bundles are arranged at the two ends of the barrel, the multiple heat exchange tube bundles are erected between the two tube plates at intervals from top to bottom, and tube boxes communicated with the heat exchange tube bundles are formed by the tube plates and the inner wall of the barrel. A pass partition plate which divides a heat medium in the tube box and enables the heat medium to flow into multiple heat exchange tube bundles from top to bottom is arranged in the tube box, the high-temperature heat medium of the heat pump exchanges heat with water vapor with the higher temperature through the pass partition plate, the temperature of the water vapor is further increased, and high-temperature and high-pressure water vapor with the temperature higher than 150 DEG C can be directly generated without arranging a booster pump and a flash tank.

Description

TECHNICAL FIELD

[0001] The utility model relates to a water vapor generating device, especially to a heat pump direct water vapor generating system. BACKGROUND

[0002] In industrial production, a large amount of high-temperature steam is needed, which is mostly obtained by burning boilers, consuming a large amount of energy and having a low energy utilization rate, and polluting the environment with waste gas and waste residue. The patent document with publication number CN118935339A discloses a water vapor system for heating cold water using heat pump to absorb heat from low-grade energy, which can reduce high-quality energy consumption and supply low-pressure steam and high-temperature hot water. The patent document with publication number CN219102952U discloses a heat pump steam generating device, which prepares high-temperature and high-pressure water vapor by setting a pressurizing pump and a flash tank. However, the water vapor obtained by the "flash system" is about 5℃ lower in temperature than the water heated by the heat pump, resulting in a loss of part of the heat pump efficiency. At the same time, the "flash system" requires heat exchange, a flash tank, and a pressure reducing valve, etc. The patent document with publication number CN114909643A discloses a compression heat pump steam unit, which uses a heat pump system to obtain low-grade energy and heats water through a heat exchanger to produce low-pressure water vapor, and then uses a water vapor compressor to increase the pressure to obtain high-temperature and high-pressure water vapor. This scheme has the following problems: 1. The water and water vapor pass through the tube side of the shell-and-tube heat exchanger, and the space in the tube side is small. After the water boils, the water vapor has a high water content. The water vapor passes through the compressor to produce high-pressure water vapor, which is prone to damage to the compressor equipment due to the high water content of the water vapor. The yield and quality of high-pressure water vapor are unstable, the production efficiency is low, the energy consumption is increased, and a gas-liquid separation device needs to be added; 2. The water is on the tube side, and the water supply is large, so the water vapor has a high water content and low pressure. A small water supply will result in insufficient steam and too much superheat of the steam. The water supply needs to be strictly controlled to control the water vapor yield, pressure, and temperature, which increases the difficulty of process control and production cost; 3. The water on the tube side is heated and vaporized to produce water vapor, and the pressure on the tube side will be higher than the water supply pressure. If the water supply is not pressurized, the water will not be supplied to the water vapor generator, increasing the production cost; 4. The heat pump refrigerant passes through the shell side of the shell-and-tube heat exchanger, and the refrigerant has a large charge, which will result in a high cost of the heat pump steam system. SUMMARY

[0003] The utility model aims at solving the problem of using a heat pump to utilize low-temperature heat sources for direct production of water vapor to improve the utilization rate of low-temperature heat sources, and provides a heat pump direct water vapor generating system.

[0004] Technical Solution: The heat pump direct-output steam generation system of this utility model includes a heat pump assembly, a water supply assembly, and a steam generator. The heat pump assembly includes a subcooling heat exchanger that subcools the refrigerant flowing out after heat exchange in the steam generator, a refrigerant throttling device, and an evaporation heat exchanger that evaporates the refrigerant into gas, connected in sequence, as well as a compressor that converts the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure refrigerant and delivers it to the steam generator. The water supply assembly includes a water preheating heat exchanger, a storage tank, a booster pump, and a water throttling device connected in sequence. A low-temperature heat source is connected in sequence to the subcooling heat exchanger, the evaporation heat exchanger, and the water preheating heat exchanger.

[0005] Furthermore, the steam generator is a shell-and-tube heat exchanger, including a shell made of carbon steel, stainless steel, or titanium alloy. Tube sheets for fixing heat exchange tube bundles are installed at both ends of the shell. The heat exchange tube bundles pass through the tube sheets and are sealed to each other, ensuring the separation of the piping and shell circuits and preventing the heat medium from mixing into the water circulation system. Multiple heat exchange tube bundles are spaced apart from top to bottom between two tube sheets. The tube sheets and the inner wall of the shell form a tube box communicating with the heat exchange tube bundles. A partition plate is installed inside the tube box to divert the refrigerant from top to bottom through the multiple heat exchange tube bundles. A refrigerant inlet connected to the compressor is located at the upper end of one tube box, and a refrigerant outlet connected to the subcooling heat exchanger is located at the lower end. A water inlet connected to a water throttling device is located at the bottom of the shell, and a steam outlet is located at the top. The steam outlet is also equipped with a pressure regulating device, which adjusts the opening according to the pressure inside the steam generator to maintain the pressure inside the steam generator at a target value, thereby maintaining the corresponding saturated steam temperature at the target value.

[0006] Furthermore, the heat exchange tube bundle is provided in at least two sets, including a first heat exchange tube bundle provided in the upper part of the cylinder for heat exchange with water vapor and a second heat exchange tube bundle provided in the lower part of the cylinder for heat exchange with water. The high-temperature refrigerant exchanges heat with the high-temperature water vapor in the upper part of the cylinder to further increase the temperature of the water vapor, and then uses it to exchange heat with the water at the bottom to generate water vapor.

[0007] Furthermore, multiple sets of the first and second heat exchange tube bundles are provided, and the partition plate cooperates with the multiple sets of first and second heat exchange tube bundles to form multiple layers. Each set of heat exchange tube bundles has at least one row of heat exchange tubes arranged side by side, and each row has multiple heat exchange tubes. By setting uniform and dense heat exchange tubes, high-temperature refrigerant is guided to the heat exchange zone, thereby improving heat exchange efficiency.

[0008] Furthermore, the cylinder is equipped with a liquid level detection device and a bypass port connected to the storage tank for controlling the liquid level. A return water control valve is installed between the bypass port and the storage tank to adjust the water level inside the cylinder, so that high-temperature water vapor can undergo gas-liquid separation on the liquid surface.

[0009] Further, the flow regulating device for regulating the pressure and flow of the pressurized water and returning the excess water to the storage tank is arranged between the booster pump and the water throttling device, and the control assembly for controlling the opening of the flow regulating device and the opening and closing of the water return control valve according to the liquid level detection device is further arranged, so that the water level in the cylinder is adjusted to keep the water level in the cylinder at a set value, so as to ensure the optimal water vaporization rate and keep the pressure and temperature of the water vapor at a set value.

[0010] Advantages: Compared with the prior art, the utility model has the advantages that: 1, the system low-temperature waste heat source exchanges heat with the refrigerant condensed by the heat pump system first and then exchanges heat with the evaporation side of the heat pump system, so that the supercooling of the refrigerant increases the refrigerating capacity of the heat pump system, and the temperature of the waste heat source is increased to increase the evaporation temperature of the heat pump system, so that the comprehensive energy efficiency of the heat pump system is improved; 2, the high-temperature heat medium of the heat pump is first exchanged with the water vapor of a higher temperature through the split partition, so that the temperature of the water vapor is further increased, the water vapor passes through the shell to realize the gas-liquid separation of the water vapor, and a flash tank is not needed to directly generate high-temperature and high-pressure water vapor higher than 150 DEG C; 3, the working efficiency of the heat pump system is improved, the charging amount of the heat medium passing through the pipeline is small, the water vapor prepared by the same heat of the heat medium has a higher temperature and a larger volume, and the energy utilization rate is greatly improved; 4, the pressure regulating device is arranged at the water vapor outlet, the bypass opening is arranged in the cylinder, and the flow regulating device is arranged in the water circulation system, so that the water level in the cylinder is kept at a set value, the gasification rate of the water vapor is ensured, and the energy utilization rate is further improved. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a structural schematic view of the utility model;

[0012] Figure 2 It is a structural schematic view of the steam generator of the utility model;

[0013] Figure 3 It is a sectional view of the steam generator of the utility model. DETAILED DESCRIPTION

[0014] The technical scheme of the utility model will be further described below with reference to the drawings.

[0015] As Figure 1The shown heat pump direct water vapor generation system comprises a heat pump assembly, a water supply assembly and a vapor generator 13. The heat pump assembly comprises a supercooling heat exchanger 14, a refrigerant throttling device 15 and an evaporation heat exchange device 16 which are connected in sequence to supercool the refrigerant flowing out of the vapor generator 13 after heat exchange, evaporate the refrigerant into gas and convert the low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure refrigerant to be delivered to the vapor generator by a compressor 26; the water supply assembly comprises a water preheating heat exchanger 17, a storage tank 18, a booster pump 19, a flow regulating device 20, a water throttling device 21 and a check valve 22 which are connected in sequence, the flow regulating device 20 is used to regulate the water pressure and flow of the booster pump 19 and return the excess pumped water to the storage tank 18; a low-temperature heat source is connected in sequence to the supercooling heat exchanger 14, the evaporation heat exchange device 16 and the water preheating heat exchanger 17.

[0016] As Figure 2 and 3As shown, the steam generator 13 is a shell-and-tube heat exchanger, including a cylinder 6 made of carbon steel, which can also be made of stainless steel or titanium alloy, the bottom of the cylinder 6 is provided with a water inlet 7 connected with a check valve 22, the top is provided with a steam outlet 11, the steam outlet 11 is also provided with a pressure regulating device 23, the side wall of the cylinder 6 is provided with a bypass port 12 for controlling the liquid level and a liquid level detection device 24, the bypass port 12 is connected with a backflow water control valve 25, the cylinder 6 is also provided with a control assembly for controlling the opening degree of the flow regulating device 20 and the opening and closing of the backflow water control valve 25 according to the liquid level detection device 24, the liquid level in the cylinder 6 is detected by the liquid level detection device 24 and maintained at a preset value: when the liquid level is lower than the preset value, the opening degree of the flow regulating device 20 is increased to increase the liquid inlet amount of the cylinder 6; when the liquid level is higher than the preset value, the opening degree of the flow regulating device 20 is reduced to reduce the liquid inlet amount of the cylinder 6 to return the liquid level to the preset value; when the liquid level is higher than the preset value and higher than the bypass port 12, the opening degree of the flow regulating device 20 is reduced to reduce the liquid inlet amount of the cylinder 6 to return the liquid level to the preset value, and the backflow water control valve 25 is opened to return the water to the storage tank 18 to accelerate the liquid level to return to the preset value quickly, by accurately adjusting the water amount in the water steam generator 13, the best water steam vaporization rate is ensured, and the pressure and temperature of the water steam are maintained at the set value. The left tube plate 4 and the right tube plate 8 for fixing the heat exchange tube bundles 5 are arranged at both ends of the cylinder 6, four groups of heat exchange tube bundles 5 are arranged between the left tube plate 4 and the right tube plate 8 from top to bottom, the heat exchange tube bundles 5 penetrate through the left tube plate 4 and the right tube plate 8 and are sealed connected with the left tube plate 4 and the right tube plate 8 by welding or expansion, the left tube plate 4 and the right tube plate 8 respectively form the left tube box 10 and the right tube box 9 communicated with the heat exchange tube bundles 5 with the inner wall of the cylinder 6, the left tube box 10 is provided with a refrigerant inlet 1 at the upper end and a refrigerant outlet 3 at the lower end, the refrigerant inlet 1 is connected with the refrigerant outlet of the compressor 26, and the refrigerant outlet 3 is connected with the refrigerant inlet of the subcooling heat exchanger 14. The four groups of heat exchange tube bundles 5 include a first heat exchange tube bundle arranged at the upper part of the cylinder 6 for heat exchange with water steam and three groups of second heat exchange tube bundles arranged at the lower part of the cylinder 6 for heat exchange with water, the first split range baffle 2-1 is arranged in the left tube box 10 to make the refrigerant in the left tube box 10 first flow into the first heat exchange tube bundle at the upper part of the cylinder 6, the second split range baffle 2-2 is arranged in cooperation with the third split range baffle 2-3 in the right tube box 9 to make the refrigerant flowing through the first heat exchange tube bundle flow through the three groups of second heat exchange tube bundles from top to bottom in sequence.

[0017] As Figure 3As shown, two rows of heat exchange tubes are arranged side by side on the first heat exchange tube bundle 5-1, and multiple heat exchange tubes are arranged in each row. Three groups of second heat exchange tube bundles 5-2, 5-3 and 5-4 are arranged in multiple rows, and multiple heat exchange tubes are arranged in each row (the number of heat exchange tubes arranged in the figure is only for illustration and does not represent the actual number of heat exchange tubes arranged). The refrigerant with the highest temperature from the compressor 26 enters the left tube box 10 through the refrigerant inlet 1, and is first introduced into the first heat exchange tube bundle 5-1 under the flow separation effect of the first sub-path partition plate 2-1, exchanges heat with the saturated water vapor in the upper part of the cylinder 6 to heat the saturated water vapor to above 150°C, and then is discharged through the steam outlet 11 at the top. The steam outlet 11 is also provided with a pressure regulating device 23, which adjusts the opening degree according to the pressure in the water vapor generator 13, so that the pressure in the water vapor generator 13 is maintained at a set target value, and the corresponding saturated water vapor temperature is maintained at a target value. The fresh water supplied by the water supply assembly is first heated by the preheating heat exchanger 17 and the waste heat source of the heat pump system to a temperature of 60-90°C, and then enters the buffer tank 18. The booster pump 19 absorbs the water in the buffer tank 18 and pressurizes it into high-pressure water, which is supplied to the water-side throttling device 21 through the flow regulating device 20 to maintain the required pressure and flow. The water pressurized by the throttling device 21 enters the shell side of the water vapor generator 13 through the check device 22. The refrigerant passing through the first heat exchange tube bundle 5-1 flows through the three groups of second heat exchange tube bundles 5-2, 5-3 and 5-4 under the flow separation effect of the second sub-path partition plate 2-2 and the third sub-path tube plate 2-3, and exchanges heat with the water at the bottom of the cylinder 6 to heat the preheated water to generate 150°C gas-liquid mixed water vapor. The cylinder 6 controls the liquid level of the cylinder 6 through the bypass port 12. The 150°C gas-liquid mixed water vapor is separated into water vapor and gas at the liquid level of the water vapor generator 13, and the water vapor enters the upper part of the cylinder 6 and is further heated to become 152°C superheated water vapor, which is then supplied to the use end through the pressure regulating device 23.

[0018] The high-temperature and high-pressure refrigerant generated by the compressor 26 is first exchanged with high-temperature water vapor, and then continuously flows back to the lower circulating water to exchange heat for generating water vapor. Since the temperature required for the bottom circulating water to generate water vapor is lower than the temperature required for water vapor heating, the high-temperature refrigerant is first contacted with the hot water vapor to further increase the temperature of the water vapor by the setting of the multi-stage heat exchange tube bundle and multiple heat exchange tubes. The heat gradually decreases, and the refrigerant flows downward to exchange heat with the bottom water circulation system for generating water vapor. Through such a setting, the cylinder 6 is divided into three functional areas: the bottom is the water vapor generation area, the liquid surface is the gas-liquid separation area, and the upper part is the water vapor heating area. No gas-liquid separation device and flash tank is needed, and high-temperature and high-pressure water vapor is directly prepared. The temperature of the prepared high-temperature and high-pressure water vapor is higher than 150℃. In actual production process, multiple groups of first and second heat exchange tube bundles can be added to further improve the heat exchange efficiency. At the same time, by adjusting the number of layers and roots of the heat exchange tubes, the refrigerant can be more uniformly and densely guided to the heat exchange area for heat exchange, improving the working efficiency and energy utilization rate.

[0019] The refrigerant after heat exchange flows back to the refrigerant circulation assembly from the refrigerant outlet 3. The low-temperature heat source at about 95℃ exchanges heat with the high-temperature refrigerant at about 155℃ from the refrigerant outlet 3 of the steam generator 13 through the subcooling heat exchanger 14. The low-temperature heat source is warmed up to about 100℃, and the refrigerant is cooled by about 20℃. The heat of the refrigerant in the circulation process is transferred to the low-temperature heat source for subsequent heat exchange with the refrigerant to evaporate the refrigerant into gas again to enter the circulation system, so that the heat is fully utilized. The refrigerant is further cooled to about 60-90℃ through the refrigerant throttling device 15. The low-temperature heat source warmed up to about 100℃ enters the evaporation heat exchange device 16 and the throttling refrigerant again for heat exchange. The low-temperature heat source is cooled to 65-95℃, and the refrigerant changes from liquid to gas state and enters the compressor 26 for circulation. The low-temperature heat source is cooled again by heat exchange with fresh water from the water supply assembly through the water preheating heat exchanger 17, and is discharged after being cooled again.

[0020] The heat of the high-temperature refrigerant at about 155℃ from the refrigerant outlet 3 of the steam generator 13 is transferred to the low-temperature heat source through the subcooling heat exchanger 14, which meets the working requirements of the refrigerant in the compressor and avoids the loss of heat of the refrigerant in the circulation process. The performance coefficient COP of the entire heating system is improved. Table 1 lists the heating performance coefficients of the same type of compressor under different working conditions.

[0021] Table 1 Working efficiency of the same type of compressor under different working conditions

[0022] Compressor model Operating condition 1 Operating condition 2 Operating condition 3 Condensing temperature / °C 150 150 150 Subcooling / °C 0 20 20 Evaporating temperature / °C 75 75 76 Refrigerating capacity / kW 41 56.8 58.7 Input power / kW 28.4 27.3 27.5 Heating capacity / kW 69.4 84.1 86.2 Heating COP 2.44 3.08 3.13 Heating capacity increase / % - 21.18％ 24.21％ Heating COP increase / % - 26.06％ 28.27％

[0023] As can be seen from Table 1, in the working condition 2, the supercooling degree of the refrigerant is increased by 20℃ after supercooling treatment, the heating capacity is increased by more than 21%, and the heating performance coefficient COP is increased by more than 26%; in the working condition 3, if the supercooling degree is increased by 20℃ and the evaporation temperature is increased by 1℃, the corresponding heating capacity and heating performance coefficient COP are increased by 24.21% and 28.27% respectively, which greatly improves the energy utilization rate and production efficiency of the entire steam generation system of the heat pump direct outlet water. The device has compact structure, small volume, high energy utilization rate, small charging amount of refrigerant in the pipeline, and the water vapor prepared by the same amount of heat refrigerant has higher temperature and larger volume, and can be used in combination with various heat pump systems such as air source heat pump, ground source heat pump (or ground temperature heat pump), water source heat pump and heat source tower heat pump.

Claims

1. A heat pump direct water outlet steam generator system comprising a heat pump assembly, a water supply assembly and a steam generator (13), characterized in that, The heat pump assembly comprises a supercooling heat exchanger (14) for supercooling the refrigerant discharged from the steam generator (13) after heat exchange, a refrigerant throttling device (15), an evaporation heat exchange device (16) for evaporating the refrigerant into gas, and a compressor (26) for converting the low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure refrigerant and delivering the refrigerant to the steam generator; the water supply assembly comprises a water preheating heat exchanger (17), a storage tank (18), a booster pump (19), and a water throttling device (21) connected in sequence; and the low-temperature heat source is connected in sequence with the supercooling heat exchanger (14), the evaporation heat exchange device (16), and the water preheating heat exchanger (17).

2. The heat pump direct water outlet steam generation system of claim 1, wherein, The steam generator (13) is a shell-and-tube heat exchanger comprising a cylinder (6), pipe plates for fixing heat exchange tube bundles (5) arranged at both ends of the cylinder (6), a plurality of heat exchange tube bundles (5) arranged in the cylinder (6) from top to bottom and spaced apart between the two pipe plates, the heat exchange tube bundles (5) being sealingly connected with the pipe plates, the pipe plates and the inner wall of the cylinder (6) forming a tube box in communication with the heat exchange tube bundles (5), a distribution partition plate (2) arranged in the tube box for distributing the refrigerant in the tube box to flow downward through the plurality of heat exchange tube bundles (5), a refrigerant inlet (1) arranged at the upper end of one side of the tube box and connected with the compressor (26), and a refrigerant outlet (3) arranged at the lower end of the tube box and connected with the supercooling heat exchanger (14); the bottom of the cylinder (6) is provided with a water inlet (7) connected with the water throttling device (21), and the top of the cylinder (6) is provided with a steam outlet (11).

3. The heat pump direct water outlet steam generation system of claim 2, wherein, The heat exchange tube bundles (5) are arranged in at least two groups, including a first heat exchange tube bundle arranged at the upper portion of the cylinder (6) for heat exchange with water vapor and a second heat exchange tube bundle arranged at the lower portion of the cylinder (6) for heat exchange with water.

4. The heat pump direct steam generation system of claim 3, wherein, The first heat exchange tube bundle and the second heat exchange tube bundle are arranged in multiple groups, and the distribution partition plate (2) is arranged in multiple layers in cooperation with the multiple groups of first heat exchange tube bundles and second heat exchange tube bundles.

5. The heat pump direct steam generation system of claim 3, wherein, Each group of heat exchange tube bundles (5) is arranged with at least one row of heat exchange tubes in parallel from top to bottom, and each row of heat exchange tubes is arranged with a plurality of heat exchange tubes.

6. The heat pump direct steam generation system of claim 2, wherein, The cylinder (6) is provided with a liquid level detection device (24) and a bypass port (12) connected with the storage tank (18) for controlling the liquid level; a backflow water control valve (25) is arranged between the bypass port (12) and the storage tank (18).

7. The heat pump direct steam generation system of claim 2, wherein, The steam outlet (11) is further provided with a pressure regulating device (23).

8. The heat pump direct steam generation system of claim 1, wherein, The booster pump (19) and the water throttling device (21) are further provided with a flow regulating device (20) for regulating the water pressure and flow rate of the booster pump (19) and returning the excess water pumped by the booster pump (19) to the storage tank (18).

9. The heat pump direct steam generation system of claim 1, wherein, The booster pump (19) and the steam generator (13) are further provided with a check valve (22).

10. The heat pump direct steam generation system of claim 1, wherein, The control assembly for controlling the opening degree of the flow regulating device (20) and the opening and closing of the backflow water control valve (25) according to the liquid level detection device (24) is further included.

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