A flash evaporation degassing system and degassing method for slurry

Abstract

This application belongs to the field of waste heat recovery technology, specifically proposing a slurry flash evaporation degassing system and degassing method, comprising: a flash tank having a first non-condensable gas outlet, a waste steam outlet, and a first non-condensable gas inlet; a heat pump for directly or indirectly heating the return water of a heat user using the waste steam from the flash tank, wherein its waste steam inlet is connected to the waste steam outlet of the flash tank, and its second non-condensable gas outlet is connected to the first non-condensable gas inlet of the flash tank; a cooler for cooling and condensing water vapor in the non-condensable gas discharged from the flash tank, having a third gas inlet and a third gas outlet, wherein the third gas inlet is connected to the first non-condensable gas outlet of the flash tank; a water ring vacuum pump having a fourth gas inlet, a liquid inlet, a liquid outlet, and a fourth exhaust port, wherein the fourth gas inlet is connected to the third gas outlet of the cooler; and a working fluid supply device for providing a low-temperature working fluid to the cooler and the water ring vacuum pump.

Description

Technical Field

[0001] This application belongs to the technical field of flash tanks, and particularly relates to a slurry flash degassing system and degassing method. Background Technology

[0002] The waste heat recovery technology of slurry flash evaporation is increasingly widely used in the waste heat recovery of coal-fired boilers. The basic principle of conventional slurry flash evaporation waste heat recovery technology is to introduce the desulfurization slurry from the desulfurization tower into a low-pressure flash tank. The pressure in the flash tank is lower than the boiling point of the slurry, so the slurry flashes after entering the flash tank, generating low-pressure steam. The flashed slurry returns to the desulfurization tower, forming a closed loop, while the low-pressure steam generated by flash evaporation flows out of the flash tank and condenses in other heat exchange devices. The condensation heat of this low-pressure steam is recovered through heat pump technology, thus completing the heat recovery.

[0003] Because the slurry has a complex composition and undergoes flash evaporation from an atmospheric pressure environment into a low-pressure flash tank, the gas emitted during flash evaporation contains not only low-pressure steam but also a large amount of non-condensable gases such as carbon dioxide and air. The presence of these non-condensable gases significantly affects the condensation heat transfer coefficient of the low-pressure steam. If left untreated, this not only results in a large heat exchange area and increased equipment investment but also leads to the accumulation of non-condensable gases, ultimately causing a loss of waste heat recovery capability. Therefore, slurry flash evaporation waste heat recovery systems typically remove these non-condensable gases. The current conventional method is to connect a vacuum pump to the flash tank to directly extract the non-condensable gases. However, because slurry flash evaporation waste heat recovery systems generally have large slurry volumes, large gas volumes, and low pressures, a single vacuum pump is insufficient to meet operational requirements. Therefore, a pump set such as a "Roots vacuum pump + water ring vacuum pump" is often used to improve the vacuuming capacity. However, this degassing method has the following problems: (1) The gas extracted by the vacuum pump is a mixture of water vapor and non-condensable gas. The presence of water vapor not only affects the performance and lifespan of the vacuum pump set, but also causes the vacuum pump set selection to be mismatched with the actual amount of non-condensable gas, resulting in equipment redundancy.

[0004] (2) The pump sets of Roots vacuum pumps and water ring vacuum pumps consume a lot of electricity, which affects the economic efficiency of waste heat recovery. Roots vacuum pumps have high operating requirements and do not allow any impurities to enter the pump. Therefore, a very fine filter screen is required in front of the pump. However, the mixed gas generated by the flash evaporation of slurry will inevitably carry slurry droplets. These slurry droplets will gradually stick to the filter screen, causing the filter screen to be blocked and affecting the operation of the vacuum pump set. Summary of the Invention

[0005] This application provides a slurry flash degassing system, comprising: A flash tank having a first non-condensable gas outlet, a waste steam outlet, and a first non-condensable gas inlet; A heat pump is used to directly or indirectly heat the return water of heat users by using the exhaust steam of a flash tank. Its exhaust steam inlet is connected to the exhaust steam outlet of the flash tank, and its second non-condensable gas outlet is connected to the first non-condensable gas inlet of the flash tank. A cooler for cooling water vapor in the non-condensable gas discharged from the flash condenser, having a third gas inlet and a third gas outlet, the third gas inlet being connected to the first non-condensable gas outlet of the flash condenser. A water ring vacuum pump has a fourth gas inlet, a liquid inlet, a liquid outlet, and a fourth exhaust outlet, wherein the fourth gas inlet is connected to the third gas outlet of the cooler; The working fluid supply device is used to supply low-temperature working fluid to the cooler to condense water vapor and to supply low-temperature working fluid to the water ring vacuum pump to maintain its pumping capacity.

[0006] Furthermore, the working fluid supply device includes a chiller and a cooling tower, which provide a low-temperature working fluid to the cooler and the water ring vacuum pump; The sixth outlet of the cooling tower is connected in three ways to the third inlet of the cooler, the liquid inlet of the water ring vacuum pump, and the cooling water inlet of the refrigeration unit; The chilled water outlet of the chiller is connected to the liquid inlet of the water ring vacuum pump, and the cooling water outlet of the chiller is connected to the sixth water inlet of the cooling tower. The outlet of the water ring vacuum pump is connected in two ways to the chilled water inlet of the refrigeration unit and the sixth water inlet of the cooling tower. The third outlet of the cooler is connected to the sixth inlet of the cooling tower; The hot water inlet of the heat pump is connected to the return water of the heat user, and the hot water outlet of the heat pump is connected to the supply water of the heat user.

[0007] Furthermore, the working fluid supply device also includes a second water pump, whose eighth inlet is connected to the sixth outlet of the cooling tower, and whose eighth outlet is connected in two ways to the third inlet of the cooler and the inlet of the water ring vacuum pump.

[0008] Furthermore, the working fluid supply device includes a chiller and a cooling tower, which provide a low-temperature working fluid to the cooler and the water ring vacuum pump; The sixth outlet of the cooling tower is connected in two ways to the third inlet of the cooler and the liquid inlet of the water ring vacuum pump. The chilled water outlet of the refrigeration unit is connected to the liquid inlet of the water ring vacuum pump; The outlet of the water ring vacuum pump is connected in two ways to the chilled water inlet of the refrigeration unit and the sixth water inlet of the cooling tower. The third outlet of the cooler is connected to the sixth inlet of the cooling tower; The cooling water inlet of the chiller is connected to the return water of the heat user, and the cooling water outlet of the chiller is connected to the hot water inlet of the heat pump. The hot water outlet of the heat pump is connected to the water supply of the heat user.

[0009] Furthermore, the working fluid supply device also includes a second water pump, whose eighth inlet is connected in two ways to the sixth outlet of the cooling tower and the cooling water inlet of the chiller, and whose eighth outlet is connected to the water ring vacuum pump.

[0010] Furthermore, the system is configured such that the cooling tower and the chiller jointly provide the cryogenic working fluid to the water ring vacuum pump, or that the cooling tower alone provides the cryogenic working fluid to the water ring vacuum pump; wherein, A second valve is installed on the pipeline connecting the liquid outlet of the water ring vacuum pump to the chilled water inlet of the refrigeration unit; A first valve is installed on the pipeline connecting the liquid inlet of the water ring vacuum pump to the chilled water outlet of the refrigeration unit; A third valve is installed on the pipeline connecting the outlet of the water ring vacuum pump to the sixth inlet of the cooling tower.

[0011] Furthermore, the working fluid supply device includes a refrigerator that provides a cryogenic working fluid to the cooler and the water ring vacuum pump; The chilled water outlet of the refrigeration unit is connected to the third water inlet of the cooler and the liquid inlet of the water ring vacuum pump in two separate paths. The third outlet of the cooler is connected to the chilled water inlet of the chiller; The outlet of the water ring vacuum pump is connected to the chilled water inlet of the refrigeration unit; The cooling water inlet of the chiller is connected to the return water of the heat user, and the cooling water outlet of the chiller is connected to the hot water inlet of the heat pump. The hot water outlet of the heat pump is connected to the water supply of the heat user.

[0012] Furthermore, the working fluid supply device also includes a second water pump, whose eighth inlet is connected to the chilled water outlet of the refrigeration unit, and whose eighth outlet is connected in two paths to the cooler and the water ring vacuum pump.

[0013] Furthermore, the first non-condensable gas inlet is located near the first non-condensable gas outlet.

[0014] This application also proposes a degassing method for a slurry flash degassing system, comprising the following steps: Start the water ring vacuum pump. Under the suction action of the water ring vacuum pump, the mixture of non-condensable gas and water vapor in the flash tank is extracted and first introduced into the cooler for cooling, so that the water vapor in the mixture is condensed into condensate and the condensate is discharged. The cooled non-condensable gas is introduced into a water ring vacuum pump for extraction. Meanwhile, the exhaust steam generated by the flash evaporation of the slurry in the flash tank is introduced into the heat pump for condensation. The heat pump uses the condensation heat of the exhaust steam to heat the user's return water and sends the remaining non-condensable gas after condensation back to the flash tank. The working fluid supply device provides a low-temperature working fluid to the cooler and the water ring vacuum pump.

[0015] The above-mentioned technical solution of this application has at least the following beneficial technical effects: The mixed gas extracted from the first non-condensable gas outlet of the flash tank is pre-cooled by a cooler, causing most of the water vapor to condense and significantly reducing the water vapor content and gas volumetric flow rate in the gas entering the water ring vacuum pump. Due to the reduced gas volumetric flow rate, the pumping capacity requirement of the vacuum pump is correspondingly reduced, creating conditions for replacing the Roots vacuum pump with a water ring vacuum pump that has a high tolerance for impurities, thus fundamentally avoiding filter clogging problems. The reduced gas volumetric flow rate means that a single-stage water ring vacuum pump can meet the pumping requirements, providing a technical basis for eliminating the need for a high-power Roots vacuum pump and reducing system power consumption. The remaining non-condensable gas after the exhaust gas in the heat pump is condensed and returned to the flash tank; only one vacuum pump is needed to simultaneously handle the non-condensable gases from both the flash tank and the heat pump, improving equipment utilization. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the slurry flash degassing system in one embodiment of this application.

[0018] Figure 2 This is a schematic diagram of the slurry flash degassing system in one embodiment of this application.

[0019] Figure 3 This is a schematic diagram of the slurry flash degassing system in one embodiment three of this application.

[0020] in, Figures 1 to 3 The correspondence between the reference numerals and component names in the attached drawings is as follows: 1-Flash tank; 101-First non-condensable gas outlet; 102-Exhaust steam outlet; 103-First non-condensable gas inlet.

[0021] 2-Heat pump; 201-Exhaust steam inlet; 202-Second non-condensable gas outlet; 203-Exhaust steam condensate outlet; 204-Hot water inlet; 205-Hot water outlet.

[0022] 3-Cooler; 301-Third gas inlet; 302-Third gas outlet; 303-Third water inlet; 304-Third water outlet.

[0023] 4-Water ring vacuum pump; 401-Liquid inlet; 402-Liquid outlet; 403-Fourth gas inlet; 404-Fourth exhaust port.

[0024] 5-Refrigeration unit; 501-Chilled water outlet; 502-Chilled water inlet; 503-Cooling water inlet; 504-Cooling water outlet.

[0025] 6-Cooling tower; 601-Sixth inlet 1; 602-Sixth inlet 2; 603-Sixth outlet; 7-Water pump 1; 701-Seventh inlet; 702-Seventh outlet; 8-Water pump 2; 801-Eighth inlet; 802-Eighth outlet; V1-First valve; V2-Second valve; V3-Third valve. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the various embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0027] First, it should be noted that, for ease of reading, port names of devices in this application system with the prefix "First" are all related to flash tank 1, such as First Non-condensable Gas Outlet 101 and First Non-condensable Gas Inlet 103. Similarly, the prefix "Second" is related to heat pump 2; the prefix "Third" is related to cooler 3; the prefix "Fourth" is related to water ring vacuum pump 4; the prefix "Sixth" is related to cooling tower 6; the prefix "Seventh" is related to water pump 7; and the prefix "Eighth" is related to water pump 8.

[0028] Example 1 See Figure 1 This embodiment provides a slurry flash evaporation degassing system, including a flash tank 1, a heat pump 2, a cooler 3, a water ring vacuum pump 4, a chiller 5, a cooling tower 6, a water pump 8, a first valve V1, a second valve V2, a third valve V3, and corresponding pipelines.

[0029] The system structure and connection relationships in this embodiment are as follows: The flash tank 1 has a first non-condensable gas outlet 101, a waste steam outlet 102, a first non-condensable gas inlet 103, a raw slurry inlet, and a return slurry outlet. The first non-condensable gas outlet 101 is located at the top of the flash tank 1, and the first non-condensable gas inlet 103 is located near the first non-condensable gas outlet 101.

[0030] Heat pump 2 has main components such as an evaporator, a condenser, a compressor, and an expansion valve. Heat pump 2 has a waste steam inlet 201, a second non-condensable gas outlet 202, a waste steam condensate outlet 203, a hot water inlet 204, and a hot water outlet 205; wherein, waste steam inlet 201 and waste steam condensate outlet 203 are located on the evaporator; hot water inlet 204 and hot water outlet 205 are located on the condenser. Under the action of a driving heat source, heat pump 2 uses the waste steam from flash tank 1 to directly or indirectly heat the return water of the heat user. The driving heat source can be steam, hot water, natural gas, or electricity. The waste steam inlet 201 of heat pump 2 is connected to the waste steam outlet 102 of flash tank 1. The second non-condensable gas outlet 202 of heat pump 2 is connected to the first non-condensable gas inlet 103 of flash tank 1. The first non-condensable gas inlet 103 of flash tank 1 is located close to the first non-condensable gas outlet 101 for convenient non-condensable gas extraction, while the waste steam outlet 102 is located further away from the first non-condensable gas outlet 101. The exhaust steam and non-condensable gas generated by flash evaporation are mixed. Most of the mixed gas enters the heat pump 2 through the exhaust steam outlet 102. In the heat pump 2, the exhaust steam is condensed. The non-condensable gas returns to the flash tank 1 through the first non-condensable gas outlet 202 to the non-condensable gas inlet 103. The first non-condensable gas inlet 103 is located near the first non-condensable gas outlet 101. This part of the non-condensable gas and a small part of the mixed gas generated by flash evaporation are drawn away through the first non-condensable gas outlet 101. When the amount of non-condensable gas drawn away is equal to the amount of non-condensable gas generated by flash evaporation, an equilibrium can be reached.

[0031] Cooler 3 is used to cool water vapor in the non-condensable gas discharged from flash tank 1. Cooler 3 has a third gas inlet 301, a third gas outlet 302, a third water inlet 303, and a third water outlet 304. The third gas inlet 301 of cooler 3 is connected to the first non-condensable gas outlet 101 of flash tank 1; the non-condensable gas after releasing heat flows out from the third gas outlet 302; the third water inlet 303 and the third water outlet 304 are the inlet and outlet of the working fluid (cold source). Cooler 3 can be a shell-and-tube heat exchanger or a plate heat exchanger.

[0032] The water ring vacuum pump 4 has a fourth gas inlet 403, a liquid inlet 401, a liquid outlet 402, and a fourth exhaust port 404. The fourth gas inlet 403 of the water ring vacuum pump 4 is connected to the third gas outlet 302 of the cooler 3.

[0033] The working fluid supply device includes a chiller 5 and a cooling tower 6. The chiller 5 has a chilled water outlet 501, a chilled water inlet 502, a cooling water inlet 503, and a cooling water outlet 504. The cooling tower 6 has a sixth outlet 603, a sixth inlet 1 601, and a sixth inlet 2 602. The chiller 5 can be a heat pump type chiller, having an evaporator, a condenser, a compressor, and a throttling valve. The chilled water outlet 501 and chilled water inlet 502 are located on the evaporator of the chiller 5, and the cooling water inlet 503 and cooling water outlet 504 are located on the condenser.

[0034] The sixth outlet 603 of the cooling tower 6 is connected to three paths: the first path connects to the third inlet 303 of the cooler 3, the second path connects to the liquid inlet 401 of the water ring vacuum pump 4, and the third path connects to the cooling water inlet 503 of the chiller 5. A water pump 7 is installed at the sixth outlet 603 of the cooling tower 6. The water pump 7 has a seventh inlet 701 and a seventh outlet 702. The seventh inlet 701 is connected to the sixth outlet 603 of the cooling tower 6, and the seventh outlet 702 is connected to three paths.

[0035] The chilled water outlet 501 of the chiller 5 is connected to the liquid inlet 401 of the water ring vacuum pump 4, and a first valve V1 is installed on this pipeline. The cooling water outlet 504 of the chiller 5 is connected to the sixth water inlet 601 of the cooling tower 6.

[0036] The outlet 402 of the water ring vacuum pump 4 is connected in two ways: one way is connected to the chilled water inlet 502 of the chiller 5 through the second valve V2, and the other way is connected to the sixth water inlet 602 of the cooling tower 6 through the third valve V3.

[0037] The third outlet 304 of the cooler 3 is connected to the sixth inlet 601 of the cooling tower 6.

[0038] Water pump 28 has an eighth inlet 801 and an eighth outlet 802. The eighth inlet 801 of water pump 28 is connected to the sixth outlet 603 of cooling tower 6, and the eighth outlet 802 is connected in two ways to the third inlet 303 of cooler 3 and the liquid inlet 401 of water ring vacuum pump 4.

[0039] The hot water inlet 204 of heat pump 2 is connected to the return water of the heat user, and the hot water outlet 205 of heat pump 2 is connected to the supply water of the heat user.

[0040] The system is configured with two operating modes: in the first mode, cooling tower 6 and chiller 5 jointly provide the cryogenic working fluid to water ring vacuum pump 4; in the second mode, cooling tower 6 provides the cryogenic working fluid to water ring vacuum pump 4 alone. Switching between these modes is achieved via valves V1, V2, and V3.

[0041] The working principle and fluid flow path of this embodiment are as follows: The exhaust steam (a mixture of water vapor and non-condensable gases) generated by the flash evaporation of the slurry in flash tank 1 flows out from exhaust steam outlet 102 and enters heat pump 2 through exhaust steam inlet 201. In heat pump 2, the exhaust steam is condensed and releases heat, and the resulting condensate is discharged from exhaust steam condensate outlet 203; the uncondensed non-condensable gases flow out from the second non-condensable gas outlet 202 of heat pump 2 and return to flash tank 1 through the first non-condensable gas inlet 103. Since the first non-condensable gas inlet 103 is located near the first non-condensable gas outlet 101, close to the top of the gas phase zone of flash tank 1, the returned non-condensable gases can be extracted in a timely manner.

[0042] After the water ring vacuum pump 4 starts, under its suction action, the non-condensable gas and a small amount of water vapor at the top of the flash tank 1 are extracted from the first non-condensable gas outlet 101 and enter the third gas inlet 301 of the cooler 3. In the cooler 3, the mixed gas is cooled by the low-temperature working liquid from the cooling tower 6 5. Most of the water vapor is condensed into condensate and discharged or merged with the working liquid at the third outlet (304) to the cooling tower 6. The remaining non-condensable gas flows out from the third gas outlet 302 of the cooler 3, enters the water ring vacuum pump 4 through the fourth gas inlet 403, and is finally discharged to the atmosphere from the fourth exhaust port 404.

[0043] The flow path of cooling water or working fluid varies depending on the working mode. Switching valves can improve the adaptability of the system and reduce power consumption throughout the entire operating cycle.

[0044] In the first operating mode (where the chiller 5 and cooling tower 6 jointly provide working fluid for the water ring vacuum pump 4), the first valve V1 is open, the second valve V2 is open, and the third valve V3 is closed. At this time, the cooling water flowing from the sixth outlet 603 of the cooling tower 6 is divided into three paths: the first path enters the chiller 3 via the third inlet 303, serving as the cold source (working fluid) for the chiller 3. After absorbing heat from the mixed gas, it returns to the sixth inlet 601 of the cooling tower 6 from the third outlet 304. The second path enters the water ring vacuum pump 4 via the inlet 401, serving as auxiliary water for the water ring vacuum pump 4. The third path enters the cooling water inlet 503 of the chiller 5, serving as the cooling water for the condenser of the chiller 5. After absorbing heat, it returns to the sixth inlet 601 of the cooling tower 6 from the cooling water outlet 504 of the chiller 5. The chilled water produced by the chiller 5 flows out from the chilled water outlet 501, enters the water ring vacuum pump 4 through the first valve V1 and the liquid inlet 401 of the water ring vacuum pump 4, and is used as the working fluid to cool the water ring vacuum pump 4; after the working fluid flows out from the liquid outlet 402, it returns to the chilled water inlet 502 of the chiller 5 through the second valve V2, forming a chilled water circulation.

[0045] In the second operating mode (cooling tower 6 provides low-temperature working fluid solely to the water ring vacuum pump 4), the first valve V1 is closed, the second valve V2 is closed, and the third valve V3 is open. At this time, the chiller 5 stops operating. The cooling water flowing from the sixth outlet 603 of cooling tower 6 is divided into two paths: one path enters the cooler 3 as a cold source, and the other path enters the water ring vacuum pump 4 via the inlet 401 as working fluid. The working fluid flowing from the outlet 402 of the water ring vacuum pump 4 returns to cooling tower 6 for heat dissipation via the third valve V3 and the sixth inlet 602 of cooling tower 6.

[0046] In this embodiment, the return water from the heat user directly enters the hot water inlet 204 of the heat pump 2. After being heated by the flash steam in the heat pump 2, it is supplied to the heat user from the hot water outlet 205 as the heat user's supply water.

[0047] In this embodiment, the mixed gas extracted from the flash tank 1 is pre-cooled by the cooler 3, causing most of the water vapor to condense. This significantly reduces the gas volume flow rate entering the water ring vacuum pump 4, allowing a single-stage water ring vacuum pump 4 to replace the Roots vacuum pump and the water ring vacuum pump unit, eliminating the need for the Roots vacuum pump, completely avoiding filter clogging, and reducing power consumption and equipment investment. The chiller 5 and / or cooling tower 6 provide the water ring vacuum pump 4 with a low-temperature working fluid, improving the pumping capacity. By switching valves, the cooling tower 6 can be used alone when the ambient temperature is low, saving chiller energy consumption. The heat pump 2 recovers the heat from the flash vapor, achieving waste heat recovery. By switching the first valve V1, the second valve V2, and the third valve V3, in winter when the temperature is low, the cooling tower 6 can be switched to provide the working fluid to the water ring vacuum pump 4 alone, shutting down the chiller 5 and saving power consumption; in summer when the temperature is high, it can be switched to a dual-cold source mode (chiller 5 and cooling tower 6 share the water supply) to ensure performance.

[0048] Example 2 See Figure 2 This embodiment is an improvement on Embodiment 1, the difference being the different flow path of the heat user return water and some adjustments to the connection relationships of the working fluid supply device. The structure and connection relationships are as follows: The exhaust steam outlet 102 of flash tank 1 is connected to the exhaust steam inlet 201 of heat pump 2; the second non-condensable gas outlet 202 of heat pump 2 is connected to the first non-condensable gas inlet 103 of flash tank 1, and the first non-condensable gas inlet 103 is located near the first non-condensable gas outlet 101; the first non-condensable gas outlet 101 of flash tank 1 is connected to the third gas inlet 301 of cooler 3; the third gas outlet 302 of cooler 3 is connected to the fourth gas inlet 403 of water ring vacuum pump 4.

[0049] The sixth outlet 603 of the cooling tower 6 is connected in two ways: the first way is connected to the third inlet 303 of the cooler 3, and the second way is connected to the inlet 401 of the water ring vacuum pump 4. The third outlet 304 of the cooler 3 is connected to the sixth inlet 601 of the cooling tower 6.

[0050] The chilled water outlet 501 of the chiller 5 is connected to the liquid inlet 401 of the water ring vacuum pump 4, and a first valve V1 is installed on this pipeline. The liquid outlet 402 of the water ring vacuum pump 4 is connected in two ways: one way is connected to the chilled water inlet 502 of the chiller 5 through the second valve V2, and the other way is connected to the sixth water inlet 602 of the cooling tower 6 through the third valve V3.

[0051] The cooling water inlet 503 of the chiller 5 is connected to the return water of the heat user, and the cooling water outlet 504 of the chiller 5 is connected to the hot water inlet 204 of the heat pump 2. The hot water outlet 205 of the heat pump 2 is connected to the supply water of the heat user.

[0052] A water pump 7 is installed at the sixth outlet 603 of the cooling tower 6. The water pump 7 has a seventh inlet 701 and a seventh outlet 702. The seventh inlet 701 is connected to the sixth outlet 603 of the cooling tower 6, and the seventh outlet 702 is connected in three ways: the first way is connected to the third inlet 303 of the cooler 3, the second way is connected to the liquid inlet 401 of the water ring vacuum pump 4, and the third way is connected to the cooling water inlet 503 of the chiller 5.

[0053] The eighth inlet 801 of water pump 2 is connected in two ways to the sixth outlet 603 of cooling tower 6 and the cooling water inlet 503 of chiller 5, and the eighth outlet 802 is connected to the liquid inlet 401 of water ring vacuum pump 4.

[0054] The system is also configured to operate in two modes, which are switched via valves.

[0055] The working principle and fluid flow path of this embodiment are as follows: the path of steam and non-condensable gas is the same as that of Embodiment 1, and will not be repeated here.

[0056] The flow paths of cooling water and working fluid vary depending on the operating mode.

[0057] In the mode where the chiller 5 and cooling tower 6 jointly provide the low-temperature working fluid for the water ring vacuum pump 4: the first valve V1 is open, the second valve V2 is open, and the third valve V3 is closed. At this time, the cooling water flowing from the sixth outlet 603 of the cooling tower 6 is divided into two paths: the first path enters the cooler 3 via the third inlet 303 as a cold source, and after absorbing heat, returns to the sixth inlet 601 of the cooling tower 6 via the third outlet 304; the second path enters the water ring vacuum pump 4 via the inlet 401 as auxiliary water. The chilled water flowing from the chilled water outlet 501 of the chiller 5 enters the inlet 401 of the water ring vacuum pump 4 via the first valve V1 as the working fluid; the working fluid flowing from the outlet 402 of the water ring vacuum pump 4 returns to the chilled water inlet 502 of the chiller 5 via the second valve V2. The heat user return water serves as the condenser cooling water for the chiller 5. It enters the cooling water inlet 503 of the chiller 5, absorbs heat from the chilled water side, and then flows out from the cooling water outlet 504 before entering the heat pump 2.

[0058] The return water from the heat users first enters the cooling water inlet 503 of the chiller 5. After absorbing heat transferred by the working fluid of the water ring vacuum pump 4 within the chiller 5, it flows out from the cooling water outlet 504 and then enters the hot water inlet 204 of the heat pump 2. In the heat pump 2, it is reheated by flash steam and finally supplied to the heat users from the hot water outlet 205. In other words, the return water from the heat users is heated in stages, recovering heat from the working fluid of the cooler 3 and the water ring vacuum pump 4, avoiding heat loss, and improving overall energy utilization efficiency.

[0059] In the mode where cooling tower 6 provides low-temperature working fluid solely to water ring vacuum pump 4, the first valve V1 is closed, the second valve V2 is closed, and the third valve V3 is open. At this time, the chiller 5 stops operating, its internal water circuit is closed or bypassed, and the return water from the heat user directly enters heat pump 2. The cooling water flowing from the sixth outlet 603 of cooling tower 6 is divided into two paths: one path enters cooler 3 as a cold source, and the other path enters water ring vacuum pump 4 via inlet 401 as working fluid. The working fluid flowing from outlet 402 of water ring vacuum pump 4 returns to cooling tower 6 for heat dissipation via the third valve V3 and the sixth inlet 602 of cooling tower 6.

[0060] In this embodiment, the return water from the heat user is connected in series to the cooling water side of the chiller 5, recovering a portion of the heat carried by the working fluid of the water ring vacuum pump 4 (which was dissipated through the cooling tower 6 in Embodiment 1), thus achieving cascade heating and improving energy utilization efficiency. Simultaneously, the dual-cold-source switching function of the cooling tower 6 and the chiller 5 is retained, allowing the cooling tower 6 to supply liquid solely to the water ring vacuum pump 4 when the ambient temperature is low, reducing operating costs. While achieving heat recovery, the switching function of the first valve V1, the second valve V2, and the third valve V3 is also retained, allowing the cooling tower 6 to supply water solely to the water ring vacuum pump 4 when the ambient temperature is low, balancing energy saving and economy.

[0061] Example 3 See Figure 3 The system consists of a flash tank 1, a heat pump 2, a cooler 3, a water ring vacuum pump 4, a refrigerator 5, a water pump 8, and piping.

[0062] The flash tank 1 has a first non-condensable gas outlet 101, a waste steam outlet 102, and a first non-condensable gas inlet 103. The first non-condensable gas inlet 103 is located near the first non-condensable gas outlet 101.

[0063] Heat pump 2 has a waste steam inlet 201, a second non-condensable gas outlet 202, a waste steam condensate outlet 203, a hot water inlet 204, and a hot water outlet 205. The waste steam inlet 201 of heat pump 2 is connected to the waste steam outlet 102 of flash tank 1. The second non-condensable gas outlet 202 of heat pump 2 is connected to the first non-condensable gas inlet 103 of flash tank 1.

[0064] The cooler 3 has a third gas inlet 301, a third gas outlet 302, a third water inlet 303, and a third water outlet 304. The third gas inlet 301 of the cooler 3 is connected to the first non-condensable gas outlet 101 of the flash tank 1.

[0065] The water ring vacuum pump 4 has a fourth gas inlet 403, a liquid inlet 401, a liquid outlet 402, and a fourth exhaust port 404. The fourth gas inlet 403 of the water ring vacuum pump 4 is connected to the third gas outlet 302 of the cooler 3.

[0066] The chiller 5 has a chilled water outlet 501, a chilled water inlet 502, a cooling water inlet 503, and a cooling water outlet 504.

[0067] The chilled water outlet 501 of the chiller 5 is connected in two ways: one way connects to the third inlet 303 of the cooler 3, and the other way connects to the inlet 401 of the water ring vacuum pump 4. The third outlet 304 of the cooler 3 is connected to the chilled water inlet 502 of the chiller 5. The outlet 402 of the water ring vacuum pump 4 is connected to the chilled water inlet 502 of the chiller 5.

[0068] The cooling water inlet 503 of the chiller 5 is connected to the return water of the heat user, and the cooling water outlet 504 of the chiller 5 is connected to the hot water inlet 204 of the heat pump 2. The hot water outlet 205 of the heat pump 2 is connected to the supply water of the heat user.

[0069] The eighth inlet 801 of water pump 2 is connected to the chilled water outlet 501 of refrigeration unit 5. The eighth outlet is split into two paths and connected to the third water inlet 303 of cooler 3 and the liquid inlet 401 of water ring vacuum pump 4.

[0070] The working principle and fluid flow path of this embodiment are as follows: The exhaust gas in flash tank 1 enters heat pump 2 for condensation, and the non-condensable gas returns to flash tank 1; water ring vacuum pump 4 draws in the mixture of non-condensable gas and water vapor at the top of flash tank 1, and after being cooled by cooler 3, the non-condensable gas enters water ring vacuum pump 4 for discharge.

[0071] The chilled water flowing from the chilled water outlet 501 of the chiller 5 is divided into two paths: one path enters the cooler 3 through the third inlet 303 as a cold source, absorbs the condensation heat of the mixed gas, and then flows out from the third outlet 304, returning to the chilled water inlet 502 of the chiller 5; the other path enters the water ring vacuum pump 4 through the inlet 401 as a working fluid, absorbs the compression heat, and then flows out from the outlet 402, also returning to the chilled water inlet 502 of the chiller 5. The cooling water inlet 503 of the chiller 5 is connected to the heat user's return water, and the cooling water outlet 504 is connected to the hot water inlet 204 of the heat pump 2.

[0072] The return water for heat users flows sequentially through the cooling water side of the chiller 5 and the hot water side of the heat pump 2 to achieve cascade heating: it first enters the cooling water inlet 503 of the chiller 5, where it absorbs the heat transferred from the chilled water side (this heat comes from the condensation heat of the cooler 3 and the working fluid compression heat of the water ring vacuum pump 4), and then flows out from the cooling water outlet 504 into the hot water inlet 204 of the heat pump 2, where it is reheated by the flash steam, and finally supplied to heat users from the hot water outlet 205.

[0073] This embodiment not only recovers the heat from the working fluid of the water ring vacuum pump 4, but also recovers a portion of the heat released during the condensation of the mixed gas in the cooler 3 (this heat was lost through the cooling tower 6 in embodiments one and two). Most of the heat obtained from the gas extracted from the flash tank and the working fluid of the water ring vacuum pump 4 is transferred to the heat user's return water via the chiller 5. The heat user's return water is heated in stages, recovering the heat from the cooler 3 and the working fluid of the water ring vacuum pump 4, avoiding heat loss, and improving overall energy efficiency. Simultaneously, the cooling tower and its cooling water circulation are eliminated, resulting in a more compact system structure, suitable for water-scarce areas or situations where cooling tower installation is restricted. This embodiment still uses only a single-stage water ring vacuum pump 4, avoiding the clogging problem of Roots vacuum pumps. Furthermore, because the chiller 5 can actively control the chilled water temperature, the working fluid temperature of the water ring vacuum pump 4 can be stably maintained at a low level, thereby improving pumping capacity and operational stability.

[0074] The above three embodiments illustrate different implementations of this application. In practical engineering, a suitable embodiment can be selected based on ambient temperature conditions, heat user needs, and on-site installation conditions. All embodiments reduce the water vapor content and gas volumetric flow rate in the gas entering the water ring vacuum pump 4 through the cooler 3, and none of them use a Roots vacuum pump, thereby solving the technical problems of equipment redundancy, high power consumption, filter clogging, and heat waste in the prior art.

[0075] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of this application and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of this application should be included within the protection scope of this application. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A slurry flash degassing system, characterized in that, include: Flash tank (1) has a first non-condensable gas outlet (101), a waste steam outlet (102) and a first non-condensable gas inlet (103). The heat pump (2) is used to directly or indirectly heat the return water of the heat user by using the exhaust steam of the flash tank (1). Its exhaust steam inlet (201) is connected to the exhaust steam outlet (102) of the flash tank (1), and its second non-condensable gas outlet (202) is connected to the first non-condensable gas inlet (103) of the flash tank (1). Cooler (3) is used to cool water vapor in the non-condensable gas discharged from the flash condenser (1), and has a third gas inlet (301) and a third gas outlet (302), the third gas inlet (301) being connected to the first non-condensable gas outlet (101) of the flash condenser (1); The water ring vacuum pump (4) has a fourth gas inlet (403), a liquid inlet (401), a liquid outlet (402) and a fourth exhaust outlet (404), wherein the fourth gas inlet (403) is connected to the third gas outlet (302) of the cooler (3); The working fluid supply device is used to supply low-temperature working fluid to the cooler (3) to condense water vapor and to supply low-temperature working fluid to the water ring vacuum pump (4) to maintain its pumping capacity.

2. The slurry flash degassing system according to claim 1, characterized in that, The working fluid supply device includes a chiller (5) and a cooling tower (6), which provide a low-temperature working fluid to the cooler (3) and the water ring vacuum pump (4); The sixth outlet (603) of the cooling tower (6) is connected in three ways to the third inlet (303) of the cooler (3), the liquid inlet (401) of the water ring vacuum pump (4), and the cooling water inlet (503) of the chiller (5). The chilled water outlet (501) of the chiller (5) is connected to the liquid inlet (401) of the water ring vacuum pump (4), and the cooling water outlet (504) of the chiller (5) is connected to the sixth water inlet (601) of the cooling tower (6). The outlet (402) of the water ring vacuum pump (4) is connected in two ways to the chilled water inlet (502) of the chiller (5) and the sixth water inlet (602) of the cooling tower (6). The third outlet (304) of the cooler (3) is connected to the sixth inlet (601) of the cooling tower (6). The hot water inlet (204) of the heat pump (2) is connected to the return water of the heat user, and the hot water outlet (205) of the heat pump (2) is connected to the supply water of the heat user.

3. The slurry flash degassing system according to claim 2, characterized in that, The working fluid supply device also includes a second water pump (8), whose eighth inlet (801) is connected to the sixth outlet (603) of the cooling tower (6), and whose eighth outlet (802) is connected in two ways to the third inlet (303) of the cooler (3) and the inlet (401) of the water ring vacuum pump (4).

4. The slurry flash degassing system according to claim 1, characterized in that, The working fluid supply device includes a chiller (5) and a cooling tower (6), which provide a low-temperature working fluid to the cooler (3) and the water ring vacuum pump (4); The sixth outlet (603) of the cooling tower (6) is connected in two ways to the third inlet (303) of the cooler (3) and the liquid inlet (401) of the water ring vacuum pump (4). The chilled water outlet (501) of the chiller (5) is connected to the liquid inlet (401) of the water ring vacuum pump (4); The outlet (402) of the water ring vacuum pump (4) is connected in two ways to the chilled water inlet (502) of the chiller (5) and the sixth water inlet (602) of the cooling tower (6). The third outlet (304) of the cooler (3) is connected to the sixth inlet (601) of the cooling tower (6). The cooling water inlet (503) of the chiller (5) is connected to the heat user return water, and the cooling water outlet (504) of the chiller (5) is connected to the hot water inlet (204) of the heat pump (2). The hot water outlet (205) of the heat pump (2) is connected to the water supply of the heat user.

5. The slurry flash degassing system according to claim 4, characterized in that, The working fluid supply device also includes a second water pump (8), whose eighth inlet (801) is connected in two ways to the sixth outlet (603) of the cooling tower (6) and the cooling water inlet (503) of the chiller (5), and whose eighth outlet (802) is connected to the water ring vacuum pump (4).

6. The slurry flash degassing system according to any one of claims 2-5, characterized in that, The system is configured such that the cooling tower (6) and the chiller (5) jointly provide the cryogenic working fluid to the water ring vacuum pump (4), or the cooling tower (6) alone provides the cryogenic working fluid to the water ring vacuum pump (4); wherein, A second valve (V2) is provided on the pipeline connecting the liquid outlet (402) of the water ring vacuum pump (4) and the chilled water inlet (502) of the refrigerator (5). A first valve (V1) is provided on the pipeline connecting the liquid inlet (401) of the water ring vacuum pump (4) and the chilled water outlet (501) of the refrigerator (5). A third valve (V3) is provided on the pipeline connecting the outlet (402) of the water ring vacuum pump (4) and the sixth inlet (602) of the cooling tower (6).

7. The slurry flash degassing system according to claim 1, characterized in that, The working fluid supply device includes a refrigerator (5), which provides a low-temperature working fluid to the cooler (3) and the water ring vacuum pump (4); The chilled water outlet (501) of the chiller (5) is connected in two ways to the third water inlet (303) of the cooler (3) and the liquid inlet (401) of the water ring vacuum pump (4). The third outlet (304) of the cooler (3) is connected to the chilled water inlet (502) of the chiller (5); The outlet (402) of the water ring vacuum pump (4) is connected to the chilled water inlet (502) of the refrigerator (5); The cooling water inlet (503) of the chiller (5) is connected to the heat user return water, and the cooling water outlet (504) of the chiller (5) is connected to the hot water inlet (204) of the heat pump (2). The hot water outlet (205) of the heat pump (2) is connected to the water supply of the heat user.

8. The slurry flash degassing system according to claim 7, characterized in that, The working fluid supply device also includes a second water pump (8), whose eighth inlet (801) is connected to the chilled water outlet (501) of the chiller (5), and whose eighth outlet is connected in two ways to the cooler (3) and the water ring vacuum pump (4).

9. The slurry flash degassing system according to claim 1, characterized in that, The first non-condensable gas inlet (103) is located near the first non-condensable gas outlet (101).

10. A degassing method for a slurry flash degassing system, characterized in that, Includes the following steps: Start the water ring vacuum pump (4). Under the suction action of the water ring vacuum pump (4), the mixture of non-condensable gas and water vapor in the flash tank (1) is extracted and first introduced into the cooler (3) for cooling, so that the water vapor in the mixture is condensed into condensate and the condensate is discharged. The cooled non-condensable gas is introduced into a water ring vacuum pump (4) for extraction; Meanwhile, the exhaust steam generated by the flash evaporation of the slurry in the flash tank (1) is introduced into the heat pump (2) for condensation. The heat pump (2) uses the condensation heat of the exhaust steam to heat the user return water and sends the remaining non-condensable gas after condensation back to the flash tank (1). The working fluid supply device provides a low-temperature working fluid to the cooler (3) and the water ring vacuum pump (4).

Images