A hot water auto-thermal recovery steam generation and cooling system and method of controlling the same

Abstract

This invention discloses a hot water self-heating recovery steam generation and cooling system, comprising a high-temperature heat pump steam generation cycle subsystem, a low-temperature cooling refrigeration cycle subsystem, and a hot water circulation subsystem. A portion of the industrial high-temperature cooling water or condensate flows into the condenser of the high-temperature heat pump cycle after passing through a cold heat exchanger to evaporate and generate steam. Another portion enters the evaporator of the high-temperature heat pump cycle to release heat and lower its temperature, and then undergoes secondary cooling in the evaporator of the low-temperature cooling cycle. Intermediate circulating water absorbs heat in the low-temperature cooling cycle condenser and then replenishes the evaporator of the high-temperature heat pump cycle. This invention utilizes a heat pump and refrigeration cycle to cool industrial high-temperature cooling water or condensate to the required temperature while fully recovering the cooling heat to generate steam required for industrial production. Simultaneously, through a flooded evaporator with a water replenishment function, the refrigerant condensation heat of the cooling cycle is rationally recovered and utilized. The system features comprehensive functionality, a small number of devices, and high energy efficiency.

Description

Technical Field

[0001] This invention belongs to the field of industrial water treatment and heat recovery technology, and relates to a system and its control method that utilizes a flooded evaporator to absorb heat from high-temperature cooling water to generate steam and low-temperature cooling water. Background Technology

[0002] The dyeing and printing industry discharges a large amount of wastewater during the production process. The temperature of the discharged wastewater is diverse and relatively high. Among them are workshop steam condensate and cooling water with high temperature and good water quality. The annual wastewater discharge in the textile industry reaches 2.029 billion tons. Workshop condensate with high temperature and good water quality accounts for about 9.6% of the total wastewater discharge, which is a considerable amount.

[0003] Currently, wastewater waste heat recovery technologies mainly include: using heat pump technology to recover wastewater waste heat, using heat exchangers for heat energy conversion, and using new multi-stage series heat exchangers to recover waste heat from wastewater. However, absorption-compression hybrid heat pumps, which can generate hot water at nearly 100°C or steam above 100°C, are rarely used in practical applications due to limitations imposed by the designer's skill level, the technical capabilities of heat pump manufacturers, and concerns about the return on investment period. Furthermore, because 9.6% of the high-temperature wastewater discharged from the dyeing and printing industry contains workshop condensate with a higher temperature and better quality than other high-temperature wastewater, technologies using heat exchangers for heat energy conversion and new multi-stage series heat exchangers to recover waste heat from high-temperature wastewater cannot efficiently recover and utilize this portion of workshop condensate.

[0004] Therefore, there is an urgent need to develop a self-heating recovery system for workshop condensate at around 90°C with good water quality, to replace the current method of directly utilizing heat pumps and heat exchangers to heat dyeing wastewater. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by proposing a hot water self-heating recovery steam generation and cooling system and its control method.

[0006] This invention utilizes a heat pump and refrigeration cycle to cool industrial high-temperature cooling water or condensate to the required temperature, while also fully recovering the cooling heat to generate steam required for industrial production. At the same time, through a flooded evaporator with a water replenishment function, the condensation heat of the refrigerant in the cooling cycle is rationally recovered and utilized. This invention reduces the energy consumption for steam supply in industrial production processes, while also improving water resource utilization and achieving higher energy efficiency.

[0007] To achieve the objectives of this invention, the technical solution adopted is as follows:

[0008] A hot water self-heating recovery steam generation and cooling system includes: a high-temperature heat pump steam generation cycle subsystem, a low-temperature cooling refrigeration cycle subsystem, and a hot water circulation subsystem. The high-temperature heat pump steam generation cycle subsystem includes: a flooded evaporator 1, a subcooling heat exchanger 2, a first condenser 3, a first compressor 4, an oil-gas separator 5, a dryer filter 6, a first expansion valve 7, an ejector 8, an oil filter 9, an oil cooler 10, and an oil pump 11. The flooded evaporator 1 has a hot water inlet a1 and a hot water outlet a2 on its tube side, and an intermediate tube side water inlet a4, a refrigerant regeneration heat exchange inlet a5, and a refrigerant reheating heat exchange outlet a5. The refrigerant regeneration heat exchange outlet is a7. The shell side is equipped with a refrigerant inlet a3 and a refrigerant outlet a6, as well as a high-level oil return port and a low-level oil return port. The refrigerant outlet a6 of the flooded evaporator 1 is connected to the inlet of the first compressor 4 through a pipeline. The outlet of the first compressor 4 is connected to the inlet c2 of the oil-gas separator 5 through a pipeline. The oil outlet c1 of the oil-gas separator 5 is connected to the inlet of the oil filter 9 through the first solenoid valve 25. The outlet of the oil filter 9 is divided into two paths: one path is connected to the inlet of the second check valve 27 through a pipeline via the oil cooler 10, and the other path is connected to the inlet of the oil pump 11 through a pipeline via the second solenoid valve 26. The outlets of oil pump 27 and oil pump 11 are connected to the first compressor 4 via pipelines; the gas outlet c3 of the oil-gas separator 5 is split into two paths, one path is connected to the inlet g1 of ejector 8 via a pipeline and the third solenoid valve 28, and the outlet g3 of ejector 8 is connected to the inlet of the first compressor 4 via a pipeline; the other path is connected to the inlet d1 of the first condenser 3 via a pipeline; the outlet d3 of the first condenser 3 is connected to the three-way solenoid valve 21 via a pipeline and the first regulating valve 20; the outlet of the three-way solenoid valve 21 is split into two paths, one path is supplied with steam via a pipeline, and the other path is vented via a pipeline; the outlet d2 of the first condenser 3 is connected to the subcooling heat exchanger via a pipeline. Inlet b3 of subcooled heat exchanger 2 and outlet b2 of subcooled heat exchanger 2 are connected to inlet k3 of first three-way regulating valve 22 via pipeline. Outlet k2 of first three-way regulating valve 22 is connected to inlet a5 of flooded evaporator 1 via pipeline. Outlet a7 of flooded evaporator 1 is connected to dryer filter 6 via first one-way valve 23 and outlet k1 of first three-way regulating valve 22 via pipeline. Outlet of dryer filter 6 is connected to inlet a3 of flooded evaporator 1 via first expansion valve 7 via pipeline. Low-level oil return port and high-level oil return port of flooded evaporator 1 are connected to inlet g2 of ejector 8 via fourth solenoid valve 29 and fifth solenoid valve 30 respectively.

[0009] The low-temperature refrigeration cycle subsystem includes: a second compressor 12, a second condenser 13, a second expansion valve 14, and a water-cooled evaporator 15; the outlet of the second compressor 12 is connected to the inlet f3 of the second condenser 13 via a pipe, the outlet f2 of the second condenser 13 is connected to the inlet e4 of the water-cooled evaporator 15 via the second expansion valve 14, and the outlet e3 of the water-cooled evaporator 15 is connected to the inlet of the second compressor 12 via a pipe.

[0010] The hot water circulation subsystem includes: a flooded evaporator 1, a subcooling heat exchanger 2, a first condenser 3, a water tank 16, a first water pump 17, a water-cooled evaporator 15, a second water pump 18, and a second condenser 13; high-temperature condensate is connected to the inlet j1 of a second three-way regulating valve 19 via a pipeline, the outlet j3 of the second three-way regulating valve 19 is connected to the inlet b1 of the subcooling heat exchanger 2 via a pipeline, the outlet b4 of the subcooling heat exchanger 2 is connected to the inlet d4 of the first condenser 3 via a pipeline; the outlet j2 of the second three-way regulating valve 19 is connected to the inlet a1 of the flooded evaporator 1 via a pipeline, and the flooded evaporator... Outlet a2 is connected to inlet h4 of water tank 16 via a pipe. Outlet h1 of water tank 16 is connected to inlet e1 of water-cooled evaporator 15 via a pipe through second water pump 18. Outlet e2 of water-cooled evaporator 15 discharges low-temperature cooling water via a pipe. Outlet h2 of water tank 16 is connected to inlet n1 of third three-way regulating valve 24 via first water pump 17 via a pipe. Outlet n3 of third three-way regulating valve 24 is connected to inlet h3 of water tank 16 via a pipe. Another outlet n2 is connected to inlet f1 of second condenser 13 via a pipe. Outlet f4 of second condenser 13 is connected to inlet a4 of flooded evaporator 1 via a pipe.

[0011] Further preferably, the first condenser 3 is a dry shell-and-tube condenser, in which the refrigerant flows through the tube side, and the hot water absorbs heat and evaporates in the shell side to generate steam. A first liquid level controller 31 is provided on the shell side, and the control signal of the first liquid level controller 31 is connected to the second three-way regulating valve 19 through a wire. A first pressure controller 38 is also provided on the shell side, and the control signal of the first pressure controller 38 is connected to the first compressor 4 and the first regulating valve 20 through a wire.

[0012] Further optimization reveals that the first expansion valve 7 is an electronic expansion valve.

[0013] Further preferred, a second pressure controller 37 is provided on the refrigerant outlet pipe of the oil-gas separator 5, and the control signal of the second pressure controller 37 is connected to the first expansion valve 7 through a wire; a second liquid level controller 32 is provided inside the oil-gas separator 5, and a third liquid level controller 33 is provided on the shell side of the full-liquid evaporator 1, and the control signals of the second liquid level controller 32 and the third liquid level controller 33 are respectively connected to the third solenoid valve 28, the fourth solenoid valve 29 and the fifth solenoid valve 30 through wires.

[0014] Further preferred, a first temperature sensor 34 is installed in the inlet pipe of the first compressor 4, and the control signal of the first temperature sensor 34 is connected to the first three-way regulating valve 22 through a wire; a differential pressure controller 39 is installed between the inlet and outlet pipes of the first compressor 4, and the control signal of the differential pressure controller 39 is connected to the second solenoid valve 26 and the oil pump 11 through wires respectively.

[0015] Further preferably, a second temperature sensor 35 is installed on the connecting pipe of the outlet f4 of the second condenser 13, and its control signal is connected to the third three-way regulating valve 24 through a wire.

[0016] Further preferably, a third temperature sensor 36 is installed on the water outlet e2 connection pipe of the water-cooled evaporator 15, and its control signal is connected to the second compressor 12 through a wire.

[0017] Further optimization is needed, the intermediate inlet a4 of the flooded evaporator 1 should be selected according to the temperature range of the water entering, i.e. the water at the outlet f4 of the second condenser 13, and a suitable tube between the first tube and the last tube should be incorporated into the flooded evaporator 1 for heat release and cooling.

[0018] To achieve the objectives of this invention, another technical solution adopted by this invention is:

[0019] A control method for a hot water self-heating recovery steam generation and cooling system includes hot water flow distribution control, steam pressure control, high-temperature heat pump compressor oil supply / return control, high-temperature heat pump compressor suction superheat control, makeup water temperature control, and cooling water outlet temperature control. The specific control methods are as follows:

[0020] Hot water flow distribution control:

[0021] Industrial high-temperature cooling water or steam condensate prioritizes steam supply. The first liquid level controller 31 in the first condenser 3 controls the flow rate of hot water into the subcooling heat exchanger 2 via the first three-way regulating valve 19. The remaining hot water enters the flooded evaporator 1 and is self-heated by the high-temperature heat pump steam generation circulation system. If the liquid level signal of the first liquid level controller 31 decreases, the flow rate of hot water into the subcooling heat exchanger 2 via the first three-way regulating valve 19 needs to be increased.

[0022] Steam pressure control:

[0023] Based on the steam pressure signal from the first pressure controller 38 on the shell side of the first condenser 3, the opening of the first regulating valve 20 is controlled first. If the steam pressure is insufficient, the opening of the first regulating valve 20 is reduced, but the opening of the first regulating valve 20 must meet the steam supply requirements of the user side. When the opening adjustment of the first regulating valve 20 cannot meet the steam pressure control requirements, the flow rate of the first compressor 4 is controlled. That is, if the steam pressure is low, the flow rate of the first compressor 4 needs to be increased, thereby increasing the heat supply of the refrigerant in the first condenser 3.

[0024] High-temperature heat pump compressor oil supply / return control:

[0025] Oil supply: The high-temperature heat pump compressor is the first compressor 4. When it starts, there is no pressure difference in the compressor's suction and discharge pipes. The second solenoid valve 26 is energized and the oil pump 11 is started. The oil pump 11 completes the oil supply to the compressor. When the pressure difference controller 39 detects the compressor suction and discharge pressure difference signal and meets the requirements, it controls the second solenoid valve 26 and the oil pump 11 to be de-energized.

[0026] Oil return: When the oil level in the oil-gas separator 5 is lower than the level setting value of the second level controller 32, or the level in the full-liquid evaporator 1 is higher than the level setting value of the third level controller 33, the system performs oil return. The second level controller 32 controls the third solenoid valve 28 and the fourth solenoid valve 29 or the fifth solenoid valve 30 to be energized. The high-pressure refrigerant gas at the outlet of the oil-gas separator 5 is ejected by the ejector 8 to return the lubricating oil above the level of the full-liquid evaporator 1 back to the suction line of the first compressor 4. When the oil return is triggered by the second level controller 32, the level signal of the third level controller 33 controls the energization of the fourth solenoid valve 29 or the fifth solenoid valve 30 to ensure that the liquid introduced by the ejector 8 is the lubricating oil above the refrigerant.

[0027] High-temperature heat pump compressor suction superheat control:

[0028] The refrigerant flow rate into the regenerative heat exchanger above the flooded evaporator 1 is controlled by the temperature sensor 34 of the suction line of the first compressor 4 via the second three-way regulating valve 22. When the suction temperature increases, the flow rate of high-temperature refrigerant entering the regenerative heat exchanger is reduced.

[0029] Water supply temperature control:

[0030] The hot water flowing out of the first-stage cooling after the flooded evaporator 1 is saturated and enters the high-temperature heat pump to generate steam. The remaining hot water and the hot water flowing out of the second condenser 13 of the low-temperature refrigeration cycle are controlled by the second temperature sensor 35 to control the flow rate of the water flowing out of the third three-way regulating valve 24 to replenish the flooded evaporator 1.

[0031] Cooling water outlet temperature control:

[0032] The secondary cooling of hot water is completed by the water-cooled evaporator 15 of the low-temperature refrigeration cycle. The temperature is controlled by the refrigerant flow of the second refrigeration compressor 14 according to the third temperature sensor 36 on its outlet pipe. When the outlet water temperature rises, the flow of the second refrigeration compressor 14 needs to be increased to increase the cooling capacity of the low-temperature refrigeration cycle.

[0033] Compared with the prior art, the technical solution of the present invention has the following advantages and beneficial effects:

[0034] By utilizing a heat pump and refrigeration cycle, this system can cool industrial high-temperature cooling water or condensate to the required temperature while fully recovering the cooling heat to generate steam for industrial production. Simultaneously, through a flooded evaporator with a water replenishment function, the system rationally recovers and utilizes the refrigerant condensation heat from the cooling cycle, improving the system's heat recovery efficiency. It also cools the discharged cooling water / condensate to the required temperature for reuse, increasing the wastewater recycling rate and reducing energy consumption. Furthermore, the system can control hot water flow distribution, steam pressure, high-temperature heat pump compressor oil supply / return, high-temperature heat pump compressor suction superheat, water replenishment temperature, and cooling water outlet temperature. Therefore, the system is characterized by comprehensive functions, a small number of devices, and high energy efficiency. The system effectively addresses the issues of improving the self-heat recovery efficiency of industrial high-temperature cooling water or steam condensate and cooling the discharged cooling water / condensate. Calculations show that when the annual discharge of high-temperature condensate from a dyeing and printing plant is 360,000 tons, with an average temperature of 90℃ and a waste heat of 2.1943 × 10^11 kJ, nearly 400 tons of steam can be produced annually. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the system of the present invention.

[0036] In the diagram: 1. Flooded evaporator; 2. Subcooling heat exchanger; 3. First condenser; 4. First compressor; 5. Oil-gas separator; 6. Dryer filter; 7. First expansion valve; 8. Ejector; 9. Oil filter; 10. Oil cooler; 11. Oil pump; 12. Second compressor; 13. Second condenser; 14. Second expansion valve; 15. Water-cooled evaporator; 16. Water tank; 17. First water pump; 18. Second water pump; 19. First three-way regulating valve; 20. First regulating valve; 21. Three-way solenoid valve; 22. 23. Second three-way regulating valve; 24. First check valve; 25. Second three-way regulating valve; 26. First solenoid valve; 27. Second check valve; 28. Third solenoid valve; 29. ​​Fourth solenoid valve; 30. Fifth solenoid valve; 31. First level controller; 32. Second level controller; 33. Third level controller; 34. First temperature sensor; 35. Second temperature sensor; 36. Third temperature sensor; 37. First pressure controller; 38. Second pressure controller; 39. Differential pressure controller. Detailed Implementation

[0037] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0038] like Figure 1As shown, a hot water self-heating recovery steam generation and cooling system of the present invention includes: a high-temperature heat pump steam generation cycle subsystem, a low-temperature cooling refrigeration cycle subsystem, and a hot water circulation subsystem. The high-temperature heat pump steam generation cycle subsystem includes: a flooded evaporator 1, a subcooling heat exchanger 2, a first condenser 3, a first compressor 4, an oil-gas separator 5, a dryer filter 6, a first expansion valve 7, an ejector 8, an oil filter 9, an oil cooler 10, and an oil pump 11. The flooded evaporator 1 has a hot water inlet a1 and a hot water outlet a2 on its tube side, and an intermediate tube side water inlet a4 and a refrigerant recovery heat exchange inlet a4. The shell side is provided with a refrigerant inlet a5 and a refrigerant heat exchange outlet a7, and a refrigerant inlet a3 and a refrigerant outlet a6, as well as a high-level oil return port and a low-level oil return port; the refrigerant outlet a6 of the flooded evaporator 1 is connected to the inlet of the first compressor 4 through a pipeline, the outlet of the first compressor 4 is connected to the inlet c2 of the oil-gas separator 5 through a pipeline, and the oil outlet c1 of the oil-gas separator 5 is connected to the inlet of the oil filter 9 through the first solenoid valve 25; the outlet of the oil filter 9 is divided into two paths, one path is connected to the inlet of the second one-way valve 27 through a pipeline via the oil cooler 10, and the other path is connected to the inlet of the oil pump 11 through the second solenoid valve 26. The outlet of the one-way valve 27 and the outlet of the oil pump 11 are connected to the first compressor 4 via pipelines; the gas outlet c3 of the oil-gas separator 5 is divided into two paths, one path is connected to the inlet g1 of the ejector 8 via a pipeline and the third solenoid valve 28, and the outlet g3 of the ejector 8 is connected to the inlet of the first compressor 4 via a pipeline, and the other path is connected to the inlet d1 of the first condenser 3 via a pipeline; the outlet d3 of the first condenser 3 is connected to the three-way solenoid valve 21 via a pipeline and the first regulating valve 20, and the outlet of the three-way solenoid valve 21 is divided into two paths, one path is supplied with steam via a pipeline, and the other path is vented via a pipeline; the outlet d2 of the first condenser 3 is connected to the subcooling heat exchanger via a pipeline. The inlet b3 of the subcooled heat exchanger 2 and the outlet b2 of the subcooled heat exchanger 2 are connected to the inlet k3 of the first three-way regulating valve 22 via a pipeline. The outlet k2 of the first three-way regulating valve 22 is connected to the inlet a5 of the flooded evaporator 1 via a pipeline. The outlet a7 of the flooded evaporator 1 is connected to the dryer filter 6 via the first one-way valve 23 and the outlet k1 of the first three-way regulating valve 22 via a pipeline. The outlet of the dryer filter 6 is connected to the inlet a3 of the flooded evaporator 1 via the first expansion valve 7 via a pipeline. The low-level oil return port and the high-level oil return port in the flooded evaporator 1 are connected to the inlet g2 of the ejector 8 via the fourth solenoid valve 29 and the fifth solenoid valve 30, respectively.

[0039] The low-temperature refrigeration cycle subsystem includes: a second compressor 12, a second condenser 13, a second expansion valve 14, and a water-cooled evaporator 15; the outlet of the second compressor 12 is connected to the inlet f3 of the second condenser 13 via a pipe, the outlet f2 of the second condenser 13 is connected to the inlet e4 of the water-cooled evaporator 15 via the second expansion valve 14, and the outlet e3 of the water-cooled evaporator 15 is connected to the inlet of the second compressor 12 via a pipe.

[0040] The hot water circulation subsystem includes: a flooded evaporator 1, a subcooling heat exchanger 2, a first condenser 3, a water tank 16, a first water pump 17, a water-cooled evaporator 15, a second water pump 18, and a second condenser 13; high-temperature condensate is connected to the inlet j1 of a second three-way regulating valve 19 via a pipeline, the outlet j3 of the second three-way regulating valve 19 is connected to the inlet b1 of the subcooling heat exchanger 2 via a pipeline, the outlet b4 of the subcooling heat exchanger 2 is connected to the inlet d4 of the first condenser 3 via a pipeline; the outlet j2 of the second three-way regulating valve 19 is connected to the inlet a1 of the flooded evaporator 1 via a pipeline, and the flooded evaporator... Outlet a2 is connected to inlet h4 of water tank 16 via a pipe. Outlet h1 of water tank 16 is connected to inlet e1 of water-cooled evaporator 15 via a pipe through second water pump 18. Outlet e2 of water-cooled evaporator 15 discharges low-temperature cooling water via a pipe. Outlet h2 of water tank 16 is connected to inlet n1 of third three-way regulating valve 24 via first water pump 17 via a pipe. Outlet n3 of third three-way regulating valve 24 is connected to inlet h3 of water tank 16 via a pipe. Another outlet n2 is connected to inlet f1 of second condenser 13 via a pipe. Outlet f4 of second condenser 13 is connected to inlet a4 of flooded evaporator 1 via a pipe.

[0041] The first condenser 3 is a dry shell-and-tube condenser, in which the refrigerant flows through the tube side and the hot water absorbs heat and evaporates in the shell side to generate steam. A first liquid level controller 31 is provided on the shell side, and the control signal of the first liquid level controller 31 is connected to the second three-way regulating valve 19 through a wire. A first pressure controller 38 is also provided on the shell side, and the control signal of the first pressure controller 38 is connected to the first compressor 4 and the first regulating valve 20 through a wire.

[0042] The first expansion valve 7 is an electronic expansion valve.

[0043] The oil-gas separator 5 is equipped with a second pressure controller 37 on the refrigerant outlet pipe. The control signal of the second pressure controller 37 is connected to the first expansion valve 7 through a wire. The oil-gas separator 5 is equipped with a second liquid level controller 32. The shell side of the full-liquid evaporator 1 is equipped with a third liquid level controller 33. The control signals of the second liquid level controller 32 and the third liquid level controller 33 are connected to the third solenoid valve 28, the fourth solenoid valve 29 and the fifth solenoid valve 30 through wires, respectively.

[0044] A first temperature sensor 34 is installed in the inlet pipe of the first compressor 4, and the control signal of the first temperature sensor 34 is connected to the first three-way regulating valve 22 through a wire; a differential pressure controller 39 is installed between the inlet and outlet pipes of the first compressor 4, and the control signal of the differential pressure controller 39 is connected to the second solenoid valve 26 and the oil pump 11 through wires respectively.

[0045] A second temperature sensor 35 is installed on the connecting pipe of the outlet f4 of the second condenser 13, and its control signal is connected to the third three-way regulating valve 24 through a wire.

[0046] A third temperature sensor 36 is installed on the outlet e2 connection pipe of the water-cooled evaporator 15, and its control signal is connected to the second compressor 12 through a wire.

[0047] The intermediate inlet a4 of the flooded evaporator 1 needs to be selected according to the temperature range of the water entering, i.e. the water at the outlet f4 of the second condenser 13, and a suitable tube between the first tube and the last tube should be incorporated into the flooded evaporator 1 for heat release and cooling.

[0048] The present invention discloses a control method for a hot water self-heating recovery steam generation and cooling system, comprising hot water flow distribution control, steam pressure control, high-temperature heat pump compressor oil supply / return control, high-temperature heat pump compressor suction superheat control, makeup water temperature control, and cooling water outlet temperature control. The specific control methods are as follows:

[0049] Hot water flow distribution control:

[0050] Industrial high-temperature cooling water or steam condensate prioritizes steam supply. The first liquid level controller 31 in the first condenser 3 controls the flow rate of hot water into the subcooling heat exchanger 2 via the first three-way regulating valve 19. The remaining hot water enters the flooded evaporator 1 and is self-heated by the high-temperature heat pump steam generation circulation system. If the liquid level signal of the first liquid level controller 31 decreases, the flow rate of hot water into the subcooling heat exchanger 2 via the first three-way regulating valve 19 needs to be increased.

[0051] Steam pressure control:

[0052] Based on the steam pressure signal from the first pressure controller 38 on the shell side of the first condenser 3, the opening of the first regulating valve 20 is controlled first. If the steam pressure is insufficient, the opening of the first regulating valve 20 is reduced, but the opening of the first regulating valve 20 must meet the steam supply requirements of the user side. When the opening adjustment of the first regulating valve 20 cannot meet the steam pressure control requirements, the flow rate of the first compressor 4 is controlled. That is, if the steam pressure is low, the flow rate of the first compressor 4 needs to be increased, thereby increasing the heat supply of the refrigerant in the first condenser 3.

[0053] High-temperature heat pump compressor oil supply / return control:

[0054] Oil supply: The high-temperature heat pump compressor is the first compressor 4. When it starts, there is no pressure difference in the compressor's suction and discharge pipes. The second solenoid valve 26 is energized and the oil pump 11 is started. The oil pump 11 completes the oil supply to the compressor. When the pressure difference controller 39 detects the compressor suction and discharge pressure difference signal and meets the requirements, it controls the second solenoid valve 26 and the oil pump 11 to be de-energized.

[0055] Oil return: When the oil level in the oil-gas separator 5 is lower than the level setting value of the second level controller 32, or the level in the full-liquid evaporator 1 is higher than the level setting value of the third level controller 33, the system performs oil return. The second level controller 32 controls the third solenoid valve 28 and the fourth solenoid valve 29 or the fifth solenoid valve 30 to be energized. The high-pressure refrigerant gas at the outlet of the oil-gas separator 5 is ejected by the ejector 8 to return the lubricating oil above the level of the full-liquid evaporator 1 back to the suction line of the first compressor 4. When the oil return is triggered by the second level controller 32, the level signal of the third level controller 33 controls the energization of the fourth solenoid valve 29 or the fifth solenoid valve 30 to ensure that the liquid introduced by the ejector 8 is the lubricating oil above the refrigerant.

[0056] High-temperature heat pump compressor suction superheat control:

[0057] The refrigerant flow rate into the regenerative heat exchanger above the flooded evaporator 1 is controlled by the temperature sensor 34 of the suction line of the first compressor 4 via the second three-way regulating valve 22. When the suction temperature increases, the flow rate of high-temperature refrigerant entering the regenerative heat exchanger is reduced.

[0058] Water supply temperature control:

[0059] The hot water flowing out of the first-stage cooling after the flooded evaporator 1 is saturated and enters the high-temperature heat pump to generate steam. The remaining hot water and the hot water flowing out of the second condenser 13 of the low-temperature refrigeration cycle are controlled by the second temperature sensor 35 to control the flow rate of the water flowing out of the third three-way regulating valve 24 to replenish the flooded evaporator 1.

[0060] Cooling water outlet temperature control:

[0061] The secondary cooling of hot water is completed by the water-cooled evaporator 15 of the low-temperature refrigeration cycle. The temperature is controlled by the refrigerant flow of the second refrigeration compressor 14 according to the third temperature sensor 36 on its outlet pipe. When the outlet water temperature rises, the flow of the second refrigeration compressor 14 needs to be increased to increase the cooling capacity of the low-temperature refrigeration cycle.

[0062] The present invention discloses a method for operating a hot water self-heating recovery steam generation and cooling system, comprising: high-temperature cooling water / condensate entering a second three-way regulating valve 19; the flow rate of hot water flowing into the subcooling heat exchanger 2 is controlled by a first liquid level controller 31 within the first condenser 3 via the second three-way regulating valve 19; the remaining hot water then enters the flooded evaporator 1; when the first liquid level controller 31 detects that the water level is too high, it controls the second three-way regulating valve 22 to reduce the flow rate of hot water into the subcooling heat exchanger 2; one stream of hot water passes through the subcooling heat exchanger 2 and enters the first condenser 3 for heat absorption and evaporation, while the other stream of hot water flows into the flooded evaporator. 1. The refrigerant liquid in the flooded evaporator 1 is heated and vaporized after heat exchange through four tubes. The high-temperature refrigerant gas enters the first compressor 4 through outlet a6. After compression, it becomes a high-temperature, high-pressure refrigerant gas and enters the oil-gas separator 5. After oil-gas separation, it enters the first condenser 3. It heats the hot water flowing into the subcooling heat exchanger 2 through four tubes, causing it to absorb heat and evaporate. The hot water is then discharged through outlet d3 for industrial production use. The first condenser 3 is equipped with a first pressure controller 38 to control the internal pressure of the first condenser 3. The steam pressure signal from the controller 38 prioritizes controlling the opening of the first regulating valve 20. If the steam pressure is insufficient, the valve opening is reduced until the opening of the first regulating valve 20 meets the user's steam supply requirements. When the opening adjustment of the first regulating valve 20 cannot meet the steam pressure control requirements, the flow rate of the first compressor 4 is controlled. That is, if the steam pressure is low, the flow rate of the first compressor 4 needs to be increased, thereby increasing the heat supply of the refrigerant in the first condenser 3. After the refrigerant gas condenses and releases heat in the first condenser 3, it becomes a high-temperature refrigerant liquid. After flowing out of the first condenser 3, it reacts with the refrigerant entering the first condenser 3 in the subcooling heat exchanger 2. The hot water in condenser 3 undergoes heat exchange, increasing the subcooling of the refrigerant liquid before entering the first three-way regulating valve 22. The first three-way regulating valve 22 is divided into two paths. The first temperature sensor 34 in the suction pipe controls the flow rate of refrigerant flowing into the regenerative heat exchange pipe above the flooded evaporator 1 through the first three-way regulating valve 22. When the suction temperature increases, the flow rate of high-temperature refrigerant entering the regenerative heat exchange pipe is reduced. The high-temperature refrigerant entering the regenerative heat exchange pipe passes through the one-way valve 23 and enters the dryer filter 6 in parallel with the other low-temperature refrigerant through the pipe. After drying and filtration, it is connected to the first expansion valve 7. After throttling and pressure reduction, it flows into the flooded evaporator 1.After heat exchange in the flooded evaporator 1, the hot water is discharged from outlet a2 and flows into the water tank 16. The hot water in the water tank 16 is divided into two paths. One path flows into the water-cooled evaporator 15 via the second water pump 18. In the water-cooled evaporator 15, the refrigerant absorbs heat and evaporates, then enters the second compressor 12 via outlet e2. In the second compressor 12, it is compressed into high-temperature and high-pressure refrigerant gas, which enters the second condenser 13 to condense and release heat. After entering the second expansion valve 14 for throttling and pressure reduction, it returns to the water-cooled evaporator 15 via inlet e4, completing the low-temperature cooling refrigeration cycle. The cooled hot water is discharged through outlet e2. A third temperature sensor 36 is installed on the outlet pipe, and the temperature is measured based on the third temperature sensor on the outlet pipe. Sensor 36 controls the refrigerant flow of the second refrigeration compressor 14 to achieve temperature control. When the outlet water temperature rises, the flow of the second refrigeration compressor 14 needs to be increased to increase the cooling capacity of the low-temperature refrigeration cycle. Another hot water is connected to the inlet f1 of the second condenser 13 via the first water pump 17. After absorbing the heat of the refrigerant in the second condenser 13 and becoming warmer, it enters the cavity d of the flooded evaporator 1 through the inlet a4 and mixes with the hot water flowing out from the heat exchange tube p1. A second temperature sensor 35 is installed in the pipeline before the outlet f4 of the second condenser 13. The second temperature sensor 35 controls the flow rate of water flowing out of the third three-way regulating valve 24 to replenish the flooded evaporator 1.

[0063] The first compressor 4 is a high-temperature heat pump compressor. When it starts, there is no pressure difference in the compressor's suction and discharge pipes. The second solenoid valve 26 is energized and the oil pump 11 is started. The oil pump 11 completes the oil supply to the compressor. After the compressor has been running for a period of time, when the pressure difference signal of the compressor's suction and discharge pipes detected by the differential pressure controller 39 meets the requirements, the second solenoid valve 26 and the oil pump 11 are de-energized. The lubricating oil comes out through the oil-gas separator 5, passes through the oil filter 9, and then enters the first compressor 4 through the oil cooler 10 and the second one-way valve 27 for oil supply.

[0064] After the system has been running for a period of time, when the oil level in the oil-gas separator 5 is lower than the set value of the second liquid level controller 32, or when the liquid level in the full-liquid evaporator 1 is higher than the set value of the third liquid level controller 33, the system will return oil. The second liquid level controller 32 will control the third solenoid valve 28 and the fourth solenoid valve 29 or the fifth solenoid valve 30 to be energized. The high-pressure refrigerant gas at the outlet of the oil-gas separator 5 will be ejected by the ejector 8 to return the lubricating oil above the liquid level of the full-liquid evaporator 1 back to the suction line of the first compressor 4. When the return oil is triggered by the second liquid level controller 32, the liquid level signal of the third liquid level controller 33 will control the energization of the fourth solenoid valve 29 or the fifth solenoid valve 30 to ensure that the liquid introduced by the ejector 8 is the lubricating oil above the refrigerant.

[0065] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A hot water self-heating recovery steam generation and cooling system, characterized in that, The system includes a high-temperature heat pump steam generation cycle subsystem, a low-temperature cooling refrigeration cycle subsystem, and a hot water circulation subsystem. The high-temperature heat pump steam generation cycle subsystem includes: a flooded evaporator (1), a subcooling heat exchanger (2), a first condenser (3), a first compressor (4), an oil-gas separator (5), a dryer filter (6), a first expansion valve (7), an ejector (8), an oil filter (9), an oil cooler (10), and an oil pump (11). The tube side of the flooded evaporator (1) is equipped with a hot water inlet valve. The hot water outlet (a2) of the tube side of the flooded evaporator (1) and the intermediate tube side water inlet (a4) of the flooded evaporator (1), the refrigerant heat exchange inlet (a5) and the refrigerant heat exchange outlet (a7) of the flooded evaporator (1), and the shell side is provided with the refrigerant inlet (a3) ​​and the refrigerant outlet (a6) of the flooded evaporator (1), as well as the high-level oil return port and the low-level oil return port; the refrigerant outlet (a6) of the flooded evaporator (1) is connected to the inlet of the first compressor (4) through a pipeline, and the first compressor (4) The outlet is connected to the inlet (c2) of the oil-gas separator (5) via a pipeline. The oil outlet (c1) of the oil-gas separator (5) is connected to the inlet of the oil filter (9) via the first solenoid valve (25). The outlet of the oil filter (9) is divided into two paths: one path is connected to the inlet of the second check valve (27) via a pipeline through the oil cooler (10), and the other path is connected to the inlet of the oil pump (11) via a pipeline through the second solenoid valve (26). The outlet of the second check valve (27) and the outlet of the oil pump (11) are connected to the first compressor (4) via a pipeline. The gas outlet (c3) of the separator (5) is split into two paths. One path is connected to the first inlet (g1) of the ejector (8) via a pipeline through the third solenoid valve (28). The outlet (g3) of the ejector (8) is connected to the inlet of the first compressor (4) via a pipeline. The other path is connected to the first inlet (d1) of the first condenser (3) via a pipeline. The second outlet (d3) of the first condenser (3) is connected to the three-way solenoid valve (21) via a pipeline through the first regulating valve (20). The outlet of the three-way solenoid valve (21) is split into two paths. One path is supplied with steam via a pipeline. The other path is vented via a pipeline.The first outlet (d2) of the first condenser (3) is connected to the second inlet (b3) of the subcooling heat exchanger (2) via a pipe. The first outlet (b2) of the subcooling heat exchanger (2) is connected to the inlet (k3) of the first three-way regulating valve (22) via a pipe. The second outlet (k2) of the first three-way regulating valve (22) is connected to the refrigerant regeneration heat exchange inlet (a5) of the flooded evaporator (1) via a pipe. The refrigerant regeneration heat exchange outlet (a7) of the flooded evaporator (1) is connected to the dryer filter (6) via the first one-way valve (23) and the first outlet (k1) of the first three-way regulating valve (22) via a pipe. The outlet of the dryer filter (6) is connected to the refrigerant inlet (a3) ​​of the flooded evaporator (1) via the first expansion valve (7) via a pipe. The low-level oil return port and the high-level oil return port in the flooded evaporator (1) are connected to the second inlet (g2) of the ejector (8) via the fourth solenoid valve (29) and the fifth solenoid valve (30) respectively. The low-temperature cooling refrigeration cycle subsystem includes: a second compressor (12), a second condenser (13), a second expansion valve (14), and a water-cooled evaporator (15); the outlet of the second compressor (12) is connected to the second inlet (f3) of the second condenser (13) through a pipe, the first outlet (f2) of the second condenser (13) is connected to the second inlet (e4) of the water-cooled evaporator (15) through the second expansion valve (14), and the second outlet (e3) of the water-cooled evaporator (15) is connected to the inlet of the second compressor (12) through a pipe; The hot water circulation subsystem includes: a flooded evaporator (1), a subcooling heat exchanger (2), a first condenser (3), a water tank (16), a first water pump (17), a water-cooled evaporator (15), a second water pump (18), and a second condenser (13); high-temperature condensate is connected to the inlet (j1) of the second three-way regulating valve (19) through a pipeline, the second outlet (j3) of the second three-way regulating valve (19) is connected to the first inlet (b1) of the subcooling heat exchanger (2) through a pipeline, and the second outlet (b4) of the subcooling heat exchanger (2) is connected to the second inlet (d4) of the first condenser (3) through a pipeline; the first outlet (j2) of the second three-way regulating valve (19) is connected to the hot water inlet (a1) of the tube side of the flooded evaporator (1) through a pipeline, and the hot water outlet (a1) of the tube side of the flooded evaporator (1) is connected to the hot water outlet (a1) of the tube side of the flooded evaporator (1). a2) is connected to the second inlet (h4) of the water tank (16) through a pipe. The first outlet (h1) of the water tank (16) is connected to the first inlet (e1) of the water-cooled evaporator (15) through a pipe via the second water pump (18). The first outlet (e2) of the water-cooled evaporator (15) discharges low-temperature cooling water through a pipe. The second outlet (h2) of the water tank (16) is connected to the inlet (n1) of the third three-way regulating valve (24) through a pipe via the first water pump (17). The outlet (n3) of the third three-way regulating valve (24) is connected to the first inlet (h3) of the water tank (16) through a pipe. The other outlet (n2) is connected to the first inlet (f1) of the second condenser (13) through a pipe. The second outlet (f4) of the second condenser (13) is connected to the intermediate pipe water supply port (a4) of the flooded evaporator (1) through a pipe.

2. The hot water self-heating recovery steam generation and cooling system according to claim 1, characterized in that, The first condenser (3) is a dry shell-and-tube condenser. The refrigerant flows through the tube side, and the hot water absorbs heat and evaporates in the shell side to generate steam. A first liquid level controller (31) is provided on the shell side. The control signal of the first liquid level controller (31) is connected to the second three-way regulating valve (19) through a wire. A first pressure controller (38) is also provided on the shell side. The control signal of the first pressure controller (38) is connected to the first compressor (4) and the first regulating valve (20) through a wire.

3. The hot water self-heating recovery steam generation and cooling system according to claim 1, characterized in that, The first expansion valve (7) is an electronic expansion valve.

4. The hot water self-heating recovery steam generation and cooling system according to claim 1, characterized in that, The oil-gas separator (5) is equipped with a second pressure controller (37) on the refrigerant outlet pipe. The control signal of the second pressure controller (37) is connected to the first expansion valve (7) through a wire. The oil-gas separator (5) is equipped with a second liquid level controller (32). The shell side of the full-liquid evaporator (1) is equipped with a third liquid level controller (33). The control signals of the second liquid level controller (32) and the third liquid level controller (33) are connected to the third solenoid valve (28), the fourth solenoid valve (29) and the fifth solenoid valve (30) through wires respectively.

5. The hot water self-heating recovery steam generation and cooling system according to claim 1, characterized in that, The first temperature sensor (34) is installed in the inlet pipe of the first compressor (4), and the control signal of the first temperature sensor (34) is connected to the first three-way regulating valve (22) through the wire; a differential pressure controller (39) is installed between the inlet and outlet pipes of the first compressor (4), and the control signal of the differential pressure controller (39) is connected to the second solenoid valve (26) and the oil pump (11) through the wire respectively.

6. The hot water self-heating recovery steam generation and cooling system according to claim 1, characterized in that, A second temperature sensor (35) is installed on the connecting pipe of the second outlet (f4) of the second condenser (13), and its control signal is connected to the third three-way regulating valve (24) through a wire.

7. The hot water self-heating recovery steam generation and cooling system according to claim 1, characterized in that, A third temperature sensor (36) is installed on the first outlet (e2) connecting pipe of the water-cooled evaporator (15), and its control signal is connected to the second compressor (12) through a wire.

8. The hot water self-heating recovery steam generation and cooling system according to claim 1, characterized in that, The intermediate tube water inlet (a4) of the flooded evaporator (1) needs to be selected according to the temperature range of the incoming water, i.e. the water at the second outlet (f4) of the second condenser (13), and then connected to the flooded evaporator (1) for heat release and cooling.

9. A control method for a hot water self-heating recovery steam generation and cooling system according to any one of claims 1 to 8, characterized in that: Hot water flow distribution control, steam pressure control, high-temperature heat pump compressor oil supply / return control, high-temperature heat pump compressor suction superheat control, makeup water temperature control, and cooling water outlet temperature control. Hot water flow distribution control: Industrial high-temperature cooling water or steam condensate prioritizes steam supply. The first liquid level controller (31) in the first condenser (3) controls the flow of hot water into the subcooling heat exchanger (2) via the second three-way regulating valve (19). The remaining hot water enters the full-liquid evaporator (1) for self-heat recovery by the high-temperature heat pump steam generation circulation system. If the liquid level signal of the first liquid level controller (31) decreases, the flow of hot water into the subcooling heat exchanger (2) via the second three-way regulating valve (19) needs to be increased. Steam pressure control: Based on the steam pressure signal from the first pressure controller (38) on the shell side of the first condenser (3), the opening of the first regulating valve (20) is controlled first. If the steam pressure is insufficient, the opening of the first regulating valve (20) is reduced, but the opening of the first regulating valve (20) must meet the steam supply requirements of the user side. When the opening adjustment of the first regulating valve (20) cannot meet the steam pressure control requirements, the flow rate of the first compressor (4) is controlled. That is, if the steam pressure is low, the flow rate of the first compressor (4) needs to be increased, thereby increasing the heat supply of the refrigerant in the first condenser (3). High-temperature heat pump compressor oil supply / return control: Oil supply: The high-temperature heat pump compressor is the first compressor (4). When it starts, there is no pressure difference in the compressor suction and discharge pipes. The second solenoid valve (26) is energized and the oil pump (11) is started. The oil pump (11) completes the oil supply to the compressor. When the pressure difference controller (39) detects the compressor suction and discharge pressure difference signal that meets the requirements, it controls the second solenoid valve (26) and the oil pump (11) to be de-energized. Oil return: When the oil level in the oil-gas separator (5) is lower than the level setting value of the second level controller (32), or the liquid level in the full-liquid evaporator (1) is higher than the level setting value of the third level controller (33), the system performs oil return. The second level controller (32) controls the third solenoid valve (28) and the fourth solenoid valve (29) or the fifth solenoid valve (30) to be energized. The high-pressure refrigerant gas at the outlet of the oil-gas separator (5) is ejected through the ejector (8) to return the lubricating oil above the liquid level of the full-liquid evaporator (1) back to the suction line of the first compressor (4). When the oil return is triggered by the second level controller (32), the liquid level signal of the third level controller (33) controls the energization of the fourth solenoid valve (29) or the fifth solenoid valve (30) to ensure that the liquid introduced by the ejector (8) is the lubricating oil above the refrigerant. High-temperature heat pump compressor suction superheat control: The first temperature sensor (34) on the inlet pipe of the first compressor (4) controls the flow of refrigerant into the regenerative heat exchange pipe above the flooded evaporator (1) via the first three-way regulating valve (22). When the suction temperature increases, the flow of high-temperature refrigerant entering the regenerative heat exchange pipe decreases. Water supply temperature control: The hot water that flows out of the first-stage cooling of the flooded evaporator (1) is saturated and enters the high-temperature heat pump to generate steam. The remaining hot water and the hot water flowing out of the second condenser (13) of the low-temperature refrigeration cycle are controlled by the second temperature sensor (35) and the third three-way regulating valve (24) to replenish the water flow of the flooded evaporator (1). Cooling water outlet temperature control: The secondary cooling of hot water is completed by the water-cooled evaporator (15) of the low-temperature refrigeration cycle. The temperature is controlled by the refrigerant flow of the second compressor (12) according to the third temperature sensor (36) on its outlet pipe. When the outlet water temperature rises, the flow of the second compressor (12) needs to be increased to increase the cooling capacity of the low-temperature refrigeration cycle.

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