Energy-saving heat pump evaporation system

Abstract

The utility model relates to an energy-saving heat pump evaporation system, which comprises a flash tower, a vacuum pump, a condenser, a heater and a discharge pump, a top outlet of the flash tower is connected with a first heat exchange pipeline inlet of the condenser through the vacuum pump; a feeding hole of the flash tower is connected with an outlet of the second heat exchange pipeline of the condenser through the heater; and a bottom outlet of the flash tower is connected with the discharge pump. The method comprises the following steps: performing vacuum evaporation on a mixed solution through a flash tower, separating a gas phase from a liquid phase, compressing the gas phase through a vacuum pump, recovering heat of the gas phase through a condenser, performing heat exchange with the fed mixed solution, taking the heat as primary heat energy for evaporation, quickly condensing the gas phase into a liquid, and reducing the pressure of a clear liquid outlet so as to save mechanical energy; the overall energy consumption of the system is effectively reduced through heat exchange in the system, and the energy-saving heat pump evaporation system is efficient in evaporation and obvious in comprehensive energy saving.

Description

Technical Field

[0001] This utility model belongs to the field of energy-saving and environmental protection technology, and specifically relates to an energy-saving heat pump evaporation system. Background Technology

[0002] Wastewater treatment essentially involves removing harmful impurities from water. Evaporation converts water into steam, thereby separating the water from its impurities. Therefore, for harmful impurities other than dissolved gases and azeotropic impurities, evaporation is a highly efficient means of thorough purification.

[0003] While evaporation technology is highly efficient, the high energy consumption of the evaporation process limits the economic viability of its large-scale application. Existing technologies reduce energy consumption through energy-saving techniques such as multi-effect evaporation, vacuum flash evaporation, and heat pump evaporation.

[0004] Multi-effect evaporation divides the evaporation process into multiple effects in series, with the steam from each effect serving as the heat source for the next effect. This allows for steam reuse and significantly reduces heat energy consumption. However, the more effects in multi-effect evaporation, the higher the energy efficiency, but also the more complex the equipment and the higher the investment cost. Vacuum flash evaporation reduces heating energy consumption by lowering the pressure, causing water to boil and evaporate at a lower temperature. This reduces the need for a high-temperature heat source and saves energy, but it requires a cooling system to rapidly condense the volume, resulting in some heat energy waste. Heat pump evaporation uses secondary steam compression and heating to improve heat recovery capabilities, making it superior to multi-effect evaporation. However, it increases mechanical energy consumption and places higher demands on equipment sealing and operational control. Utility Model Content

[0005] To address the aforementioned problems in the existing technology, this utility model provides an energy-saving heat pump evaporation system. The technical problem to be solved by this utility model is achieved through the following technical solution:

[0006] An energy-saving heat pump evaporation system includes: a flash tower, a vacuum pump, a condenser, a heater, and a discharge pump, wherein...

[0007] The top outlet of the flash tower is connected to the inlet of the first heat exchange pipeline of the condenser via a vacuum pump.

[0008] The feed inlet of the flash tower is connected to the outlet of the second heat exchange pipeline of the condenser through the heater;

[0009] The bottom outlet of the flash tower is connected to the discharge pump.

[0010] In one feasible embodiment, the outlet of the discharge pump is connected to the concentrate outlet and the inlet of the second heat exchange line of the condenser.

[0011] In one feasible embodiment, the outlet of the first heat exchange line of the condenser is connected to the clear liquid outlet.

[0012] In one feasible embodiment, the second heat exchange line inlet of the condenser is connected to the mixture inlet.

[0013] In one feasible embodiment, flash packing is provided in the middle of the flash tower;

[0014] The top of the flash tower is equipped with demisting packing.

[0015] The flash tower is provided with a first maintenance manhole and a second maintenance manhole.

[0016] A level gauge is installed at the bottom outlet of the flash tower.

[0017] In one feasible embodiment, the flash packing is a Pall ring, and the thickness of the flash packing is 2 to 4 times the inner diameter of the flash tower;

[0018] The thickness of the demisting packing is less than or equal to 0.5 meters, and the demisting packing is 250Y stainless steel packing.

[0019] The level gauge is a magnetic float level gauge.

[0020] In one feasible approach, pressure sensors and temperature sensors are installed on the body of the flash tower.

[0021] In one feasible manner, the vacuum pump is a Roots vacuum pump;

[0022] The condenser is a shell-and-tube heat exchanger, with the first heat exchange tube being the shell side and the second heat exchange tube being the tube side;

[0023] The heater is an electric heating heat exchanger, and the heater is fed from bottom to top.

[0024] The discharge pump is a gear pump, screw pump, or self-priming pump.

[0025] In one feasible embodiment, the condenser is a U-tube heat exchanger or a floating head heat exchanger with an expansion joint.

[0026] In one feasible embodiment, a Y-type filter is provided at the inlet end of the discharge pump.

[0027] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0028] The energy-saving heat pump evaporation system provided by this utility model uses a flash tower to vacuum evaporate a mixture, separating the gas and liquid phases. The gas phase is compressed by a vacuum pump and then the heat of the gas phase is recovered by a condenser. This heat is exchanged with the feed mixture as the primary heat energy for evaporation, and the gas phase is rapidly condensed into liquid, reducing the pressure at the clear liquid outlet and thus saving mechanical energy. The heat exchange within the system effectively reduces the overall energy consumption of the system. This energy-saving heat pump evaporation system has high evaporation efficiency and significant comprehensive energy savings. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of an energy-saving heat pump evaporation system provided in an embodiment of this utility model.

[0030] Figure label:

[0031] 1: Flash evaporator; 101: Flash packing; 102: Demisting packing; 103: First maintenance manhole; 104: Second maintenance manhole; 105: Level gauge; 2: Vacuum pump; 3: Condenser; 4: Heater; 5: Discharge pump. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0033] Example 1

[0034] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of an energy-saving heat pump evaporation system provided in an embodiment of this utility model.

[0035] This embodiment provides an energy-saving heat pump evaporation system, comprising: a flash tower 1, a vacuum pump 2, a condenser 3, a heater 4, and a discharge pump 5. The top outlet of the flash tower 1 is connected to the inlet of the first heat exchange pipeline of the condenser 3 via the vacuum pump 2. The feed inlet of the flash tower 1 is connected to the outlet of the second heat exchange pipeline of the condenser 3 via the heater 4. The bottom outlet of the flash tower 1 is connected to the discharge pump 5.

[0036] In this embodiment, the outlet of the discharge pump 5 is connected to the concentrate outlet and the inlet of the second heat exchange pipeline of the condenser 3. The outlet of the first heat exchange pipeline of the condenser 3 is connected to the clear liquid outlet. The inlet of the second heat exchange pipeline of the condenser 3 is connected to the mixed liquid inlet.

[0037] Specifically, the second heat exchange pipeline of condenser 3, heater 4, and the feed inlet of flash tower 1 are connected to form the mixed liquid feed route. The top outlet of flash tower 1, vacuum pump 2, and the first heat exchange pipeline of condenser 3 are connected to form the clear liquid collection route. The bottom outlet of flash tower 1 and discharge pump 5 form the concentrated liquid collection route. A branch line is also provided on the outlet pipeline of discharge pump 5, which connects to the second heat exchange pipeline of condenser 3. Therefore, the bottom outlet of flash tower 1, discharge pump 5, the second heat exchange pipeline of condenser 3, and heater 4 form the bottom reflux route of the tower.

[0038] Driven by external power, the mixture flows from the mixture inlet through the pipeline to the inlet of the second heat exchange pipeline at the lower left end of the condenser 3, enters the mixture feed route, and after being preheated by the recovered heat energy of the condenser 3, flows into the inlet of the heater 4. After being heated by the heater 4, it enters the flash tower 1 through the pipeline. The flash tower 1 performs vacuum flash evaporation on the mixture at -0.08MPa, separating the mixture into a gas phase and a liquid phase.

[0039] The gas phase rises to the top of the flash tower 1 and enters the clear liquid collection route. Specifically, the gas phase enters the inlet of the vacuum pump 2 through the pipeline from the top outlet of the flash tower 1. After the gas phase is mechanically compressed and heated inside the vacuum pump 2, it flows from the outlet of the vacuum pump 2 to the upper inlet of the condenser 3 and enters the first heat exchange pipeline of the condenser 3. After exchanging heat with the feed mixture in the condenser 3, the gas phase condenses into liquid and flows out from the lower right outlet of the condenser 3. Then, it is automatically discharged to the clear liquid outlet through the drain valve.

[0040] The liquid phase (concentrate) enters the concentrate collection route from the bottom of the flash tower 1. Specifically, the concentrate flows from the bottom outlet of the flash tower 1 to the discharge pump 5. After being pressurized by the discharge pump 5, the concentrate is discharged to the concentrate outlet through the electric regulating valve.

[0041] When the energy-saving heat pump evaporation system starts working, the heat and materials inside the system have not yet reached a state of equilibrium, and the concentration ratio of the concentrate is not up to standard. At this time, the concentrate is not directly collected, but is mixed with the mixed liquid feed through the bottom reflux route and then circulated to flash tower 1 for flash evaporation again until the system heat is balanced, the temperature and pressure of flash tower 1 are normal, and the concentration ratio of the concentrate meets the standard. Then, the valve of the bottom reflux route is closed, and the concentrate is discharged to the concentrate outlet.

[0042] Furthermore, when the energy-saving heat pump evaporation system stops operating, first turn off the power input to heater 4, then close the inlet of the mixed liquid. Under residual heat conditions, further concentrate the material in flash tower 1 using the bottom reflux route, then turn off vacuum pump 2 and drain the remaining material in flash tower 1 using discharge pump 5. After the material in flash tower 1 is drained, soft water is introduced into the inlet of the second heat exchange pipe of condenser 3 to completely clean and empty the inside of the energy-saving heat pump evaporation system. The washing liquid can be returned to the raw material (mixture) or stored separately for priority use in the next operating cycle. The washing process prevents crystallization and blockage inside the energy-saving heat pump evaporation system, and emptying prepares for the next cycle and prevents damage from freezing and cracking at extremely low temperatures. After drying and checking for any issues, turn off all electrical instruments for safe standby.

[0043] In one feasible implementation, the condenser 3 is a shell-and-tube heat exchanger, with the first heat exchange pipe being the shell side and the second heat exchange pipe being the tube side. That is, the vapor phase from the flash tower 1 exits through the shell side of the condenser 3, while the feed mixture exits through the tube side. Heat exchange occurs within the condenser 3, effectively recovering heat from the vapor phase of the flash tower 1 and reducing energy consumption. Preferably, to reduce thermal stress corrosion, the condenser 3 is a U-tube heat exchanger or a floating head heat exchanger with an expansion joint. Pressure and temperature sensors are installed on both the inlet and outlet pipes of the condenser 3, and both sensors are connected to an external automatic control system.

[0044] In this embodiment, flash packing 101 is provided in the middle of the flash tower 1, and demisting packing 102 is provided at the top of the flash tower 1. A first maintenance manhole 103 and a second maintenance manhole 104 are provided on the tower body of the flash tower 1, and a level gauge 105 is provided at the bottom outlet of the flash tower 1. A pressure sensor and a temperature sensor are provided on the tower body of the flash tower 1.

[0045] Specifically, flash packing 101 is installed inside flash tower 1, below the feed inlet. Demisting packing 102 is installed inside flash tower 1 near the top outlet. Flash packing 101 and demisting packing 102 divide flash tower 1 into upper, middle, and lower sections. The first maintenance manhole 103 is located in the upper part of flash tower 1, and the second maintenance manhole 104 is located in the middle part of flash tower 1. Pressure and temperature sensors are installed in all three sections of flash tower 1, and these sensors are connected to an external programmable logic controller (PLC) monitoring system. A soft water flushing port to prevent crystallization blockage is added to the base of the level gauge 105. A distributor is installed at the feed inlet of flash tower 1, and the specific type of distributor can be determined according to the evaporation characteristics of the mixed liquid.

[0046] In this embodiment, the flash packing 101 is a Pall ring, and its thickness is 2 to 4 times the inner diameter of the flash tower 1. The demister packing 102 has a thickness of less than or equal to 0.5 meters and is made of 250Y stainless steel, with a material of 316 or higher stainless steel. The level gauge 105 is a magnetic float level gauge. Furthermore, the level gauge 105 is a local and remote magnetic float level gauge, and its output signal controls the discharge pump 5 through an external control system.

[0047] In this embodiment, vacuum pump 2 is a Roots vacuum pump, which can be used in series in 1 to 3 stages. Pressure and temperature sensors are installed at both the inlet and outlet of vacuum pump 2. The Roots vacuum pump can draw gas to create a vacuum environment at the inlet and compress the gas at the outlet, thereby increasing the gas temperature and pressure. In application, it works in conjunction with the subsequent condenser 3 to recover heat from the high-temperature and high-pressure gas, preheating the feed mixture by heat exchange, and causing the gas phase to condense rapidly into liquid. This replaces the cooling water in the existing vacuum system, realizing the combination of vacuum flash evaporation and heat pump evaporation, reducing the pressure at the clear liquid outlet, thereby saving mechanical energy. The evaporation is highly efficient and the overall energy saving is significant.

[0048] In this embodiment, heater 4 is an electric heating heat exchanger. The heater 4 is fed from bottom to top, meaning the outlet of the second heat exchange pipe of condenser 3 is connected to the inlet at the lower right end of heater 4, and the outlet at the upper left end of heater 4 is connected to the inlet of flash tower 1. This bottom-in, top-out configuration ensures that heater 4 is fully submerged, preventing the heating element from burning dry. A temperature sensor is installed at the outlet of heater 4 for automatic temperature control. The outlet flow rate of heater 4 is automatically adjusted according to the gas phase outflow rate of flash tower 1. The discharge pump 5 needs to continuously discharge under vacuum conditions. The discharge pump 5 is installed at least 5 meters below the bottom of flash tower 1. The discharge pump 5 is a gear pump, screw pump, or self-priming pump with strong self-priming capability. The pipe diameter at the inlet of discharge pump 5 is more than twice the inlet diameter of discharge pump 5, and a Y-type filter is installed at the inlet end of discharge pump 5.

[0049] In one feasible approach, all equipment and connecting pipes in an energy-efficient heat pump evaporation system are equipped with freeze-proof electric heat tracing and are fitted with thermal insulation layers that meet the minimum temperature requirements of the operating environment. The equipment materials meet material corrosion protection requirements, and the automatic control and power systems meet the user's explosion-proof requirements.

[0050] The energy-saving heat pump evaporation system provided in this embodiment uses a flash tower 1 to vacuum evaporate the mixture, separating the gas and liquid phases. The gas phase is then compressed by a vacuum pump 2 and its heat is recovered by a condenser 3. This heat is exchanged with the feed mixture as the primary heat energy for evaporation, and the gas phase is rapidly condensed into liquid, reducing the pressure at the clear liquid outlet and thus saving mechanical energy. The heat exchange within the system effectively reduces the overall energy consumption of the system. This energy-saving heat pump evaporation system has high evaporation efficiency and significant overall energy savings.

[0051] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the protection scope of the present invention.

Claims

1. An energy efficient heat pump evaporation system, characterized in that, The application relates to a condensate recovery device for a distillation tower, which comprises a flash tower (1), a vacuum pump (2), a condenser (3), a heater (4) and a discharge pump (5), wherein, a top outlet of the flash tower (1) is connected with a first heat exchange pipeline inlet of the condenser (3) through the vacuum pump (2); a feed inlet of the flash tower (1) is connected with a second heat exchange pipeline outlet of the condenser (3) through the heater (4); a bottom outlet of the flash tower (1) is connected with the discharge pump (5). An outlet of the discharge pump (5) is connected with a concentrated liquid outlet and a second heat exchange pipeline inlet of the condenser (3).

2. The energy-efficient heat pump vaporization system of claim 1, wherein, A first heat exchange pipeline outlet of the condenser (3) is connected with a clear liquid outlet.

3. The energy-efficient heat pump vaporization system of claim 1, wherein, A second heat exchange pipeline inlet of the condenser (3) is connected with a mixed liquid inlet.

4. The energy-efficient heat pump vaporization system of claim 1, wherein, A middle part in the flash tower (1) is provided with flash packing (101); 5. The energy-efficient heat pump evaporative system of claim 1, wherein, A top part in the flash tower (1) is provided with demisting packing (102); A tower body of the flash tower (1) is provided with a first manhole (103) and a second manhole (104); A bottom outlet of the flash tower (1) is provided with a liquid level meter (105). The flash packing (101) is a Pall ring, and the thickness of the flash packing (101) is 2-4 times of the inner diameter of the flash tower (1); 6. An energy efficient heat pump vapor compression system according to claim 5 wherein, The thickness of the demisting packing (102) is less than or equal to 0.5 m, and the demisting packing (102) is 250Y stainless steel packing; The liquid level meter (105) is a magnetic float liquid level meter. The tower body of the flash tower (1) is provided with a pressure sensor and a temperature sensor.

7. An energy efficient heat pump vapor compression system according to claim 1 wherein, The vacuum pump (2) is a Roots vacuum pump; 8. An energy efficient heat pump vapor compression system according to claim 1 wherein, The condenser (3) is a tube-type heat exchanger, the first heat exchange pipeline is a shell pass, and the second heat exchange pipeline is a tube pass; The heater (4) is an electric heating heat exchanger, and the feeding mode of the heater (4) is down feeding and up discharging; The discharge pump (5) is a gear pump, a screw pump or a self-priming pump. The condenser (3) is a U-shaped tube heat exchanger or a floating head heat exchanger with an expansion joint.

9. An energy efficient heat pump vapor compression system according to claim 8 wherein, An inlet end of the discharge pump (5) is provided with a Y-shaped filter.

10. An energy efficient heat pump vapor compression system according to claim 8 wherein, ​

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