CN115432758A

CN115432758A - Sewage recovery system and recovery method

Info

Publication number: CN115432758A
Application number: CN202211207520.0A
Authority: CN
Inventors: 宋树昆; 王明仁; 孟凡通; 吴欢欢
Original assignee: Wanguo Data Service Co ltd
Current assignee: Wanguo Data Service Co ltd
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2022-12-06

Abstract

The present disclosure relates to a sewage recovery system and a recovery method, the sewage recovery system comprising: the first heat exchanger is provided with a first inlet, a first outlet, a second inlet and a second outlet, the first inlet is used for introducing a gaseous refrigerant, and the first outlet is communicated with the first inlet and used for discharging a liquid refrigerant formed by condensation and heat exchange of the gaseous refrigerant and sewage; the second inlet is used for introducing sewage, and the second outlet is used for discharging water vapor formed after the sewage and the gaseous refrigerant are evaporated and heat exchanged; the second heat exchanger is provided with a third inlet, a third outlet, a fourth inlet and a fourth outlet, the third inlet is used for introducing condensed water formed by water vapor, and the third outlet is communicated with the third inlet and used for discharging the condensed water subjected to heat exchange with the sewage to be recovered; the fourth inlet is used for introducing sewage to be recovered, and the fourth outlet is communicated with the fourth inlet and the second inlet and is used for introducing the sewage subjected to heat exchange with the condensed water into the first heat exchanger.

Description

Sewage recovery system and recovery method

Technical Field

The disclosure relates to the technical field of sewage recovery, in particular to a sewage recovery system and a recovery method.

Background

With the increasing demand of fresh water resources, the requirements for the recycling of water resources and the development of technologies are also higher. The sewage is generally simply treated and then directly discharged to a municipal sewage system or discharged on site, which increases the load of municipal sewage treatment and even directly loses the part of water resources. The sewage has the problems of too high concentration of pollutants, too large conductivity and the like, and the direct utilization can increase the risks of equipment corrosion, scaling, pipe blockage and the like, so the sewage needs to be recycled.

At present, the technologies for recovering the sewage mainly include a distillation method, a membrane method, an electrodialysis method, a freezing method and the like, but the sewage recovery efficiency of the devices is low.

Disclosure of Invention

The present disclosure provides a sewage recovery system and a recovery method, which can improve the sewage recovery efficiency.

According to an aspect of the present disclosure, there is provided a wastewater recovery system including:

the first heat exchanger is provided with a first inlet, a first outlet, a second inlet and a second outlet, the first inlet is used for introducing a gaseous refrigerant, and the first outlet is communicated with the first inlet and used for discharging a liquid refrigerant formed by condensation and heat exchange of the gaseous refrigerant and sewage; the second inlet is used for introducing sewage, and the second outlet is used for discharging water vapor formed after the sewage and the gaseous refrigerant are evaporated and heat exchanged; and

the second heat exchanger is provided with a third inlet, a third outlet, a fourth inlet and a fourth outlet, the third inlet is used for introducing condensed water formed by water vapor, and the third outlet is communicated with the third inlet and used for discharging the condensed water after heat exchange with the sewage to be recovered; the fourth inlet is used for introducing sewage to be recovered, and the fourth outlet is communicated with the fourth inlet and the second inlet and is used for introducing the sewage subjected to heat exchange with the condensed water into the first heat exchanger.

In some embodiments, the wastewater recovery system further comprises:

a compressor; and

the third heat exchanger is provided with a fifth inlet, a fifth outlet, a sixth inlet and a sixth outlet, the fifth inlet is communicated with the first outlet, the fifth outlet is communicated with the first inlet through a compressor, the sixth inlet is communicated with the second outlet, the sixth outlet is communicated with the sixth inlet and the third inlet, and the third heat exchanger is used for exchanging heat between the liquid refrigerant and the water vapor to realize phase change.

In some embodiments, the wastewater recovery system further comprises: parallelly connected first pipeline and second pipeline, and the respective first end of first pipeline and second pipeline all communicates with the sixth export, and respective second end all communicates with the third import, and first pipeline is used for holding the gas in the condensate water, is equipped with vapour and liquid separator in the second pipeline.

In some embodiments, the wastewater recovery system further comprises:

the liquid level detection component is arranged on the first pipeline and is used for detecting the liquid level of the condensed water in the first pipeline; and

and the first on-off valve and the second on-off valve are arranged on the first pipeline and are respectively positioned on two sides of the liquid level detection part.

In some embodiments, the wastewater recovery system further comprises:

the third pipeline is connected with the third outlet and used for leading out condensed water;

the negative pressure pump is arranged on the third pipeline; and

and the exhaust valve is arranged on the third pipeline and is positioned at the inlet of the negative pressure pump, and the exhaust valve is communicated with the first pipeline and is used for exhausting gas in the condensed water in an opening state.

In some embodiments, the wastewater recovery system further comprises a connection pipe through which the discharge valve communicates with the first pipe.

In some embodiments, the wastewater recovery system further comprises:

the third pipeline is connected with the third outlet and used for leading out condensed water; and

and the negative pressure pump is arranged on the third pipeline and used for keeping negative pressure in the first heat exchanger.

In some embodiments, the negative pressure pump is a variable frequency pump and the operating frequency is configured to be adjusted according to a demand amount of condensate water and/or a production amount of condensate water.

In some embodiments, the wastewater recovery system further comprises:

and the check valve is arranged on the third pipeline and is used for only allowing the condensed water to flow in a single direction from the third outlet along the third pipeline.

In some embodiments, the first heat exchanger further has a slag outlet, and the wastewater recovery system further comprises:

the slag settling container is provided with a seventh inlet and a seventh outlet, and the seventh inlet is connected with the slag outlet; and

and the sludge drying container is connected with the seventh outlet.

In some embodiments, the wastewater recovery system further comprises:

the fourth break valve is arranged on a pipeline between the slag outlet and the seventh inlet; and/or

And the fifth on-off valve is arranged on a pipeline between the seventh outlet and the sludge drying container.

In some embodiments, the sediment container has a water inlet, and the wastewater recovery system further comprises:

and two ends of the fourth pipeline are respectively communicated with the fifth pipeline and the water inlet, the fifth pipeline is used for introducing sewage to be treated, and the fourth pipeline is provided with a sixth on-off valve so as to feed water into the sediment container in the on state of the sixth on-off valve.

According to another aspect of the present disclosure, there is provided a recycling method of a sewage recycling system based on the above embodiments, including:

the sewage to be recovered and the condensed water recovered from the sewage are subjected to heat exchange through a second heat exchanger so as to preheat the sewage to be recovered, and the condensed water is led out after heat exchange;

the preheated sewage and the gaseous refrigerant are subjected to heat exchange through the first heat exchanger, so that the gaseous refrigerant is condensed and subjected to heat exchange to form a liquid refrigerant, and the sewage is evaporated and subjected to heat exchange to form vapor so as to enter the second heat exchanger after condensate water is formed.

In some embodiments, the recycling method further comprises:

and the liquid refrigerant and the vapor exchange heat through the third heat exchanger so that the liquid refrigerant is evaporated and exchanges heat to form a gaseous refrigerant, the gaseous refrigerant is compressed by the compressor and then enters the first heat exchanger, and the vapor is condensed and exchanged heat to form condensed water which enters the second heat exchanger.

In some embodiments, a first pipeline and a second pipeline are arranged between the second heat exchanger and the third heat exchanger in parallel, the first pipeline is used for containing gas in condensed water, a gas-liquid separator is arranged on the second pipeline, a liquid level detection part is arranged on the first pipeline, and a first on-off valve and a second on-off valve are respectively arranged on the first pipeline and positioned on two sides of the liquid level detection part; the recovery method further comprises:

in the process of sewage recovery, the first on-off valve and the second on-off valve are both in an on state;

and under the condition that the liquid level detection component needs maintenance, the first on-off valve and the second on-off valve are both in an off state.

In some embodiments, the wastewater recovery system further comprises: the third pipeline is used for leading out the condensed water passing through the first heat exchanger; the negative pressure pump is arranged on the third pipeline; the recovery method further comprises:

and in the sewage recovery process, the working frequency of the negative pressure pump is adjusted according to the demand load of the condensed water and/or the amount of the generated condensed water.

In some embodiments, the first heat exchanger further has a slag outlet, and the wastewater recovery system further comprises: the slag settling container is provided with a seventh inlet and a seventh outlet, and the seventh inlet is connected with the slag outlet; the sludge drying container is connected with the seventh outlet; a fourth on-off valve is arranged on a pipeline between the slag outlet and the seventh inlet, and a fifth on-off valve is arranged on a pipeline between the seventh outlet and the sludge drying container; the recovery method further comprises:

in the sewage recovery process, the fourth on-off valve is in an on state, and the fifth on-off valve is in an off state;

in the slag discharging process, the fourth on-off valve is in an off state, and the fifth on-off valve is in an on state, so that the sludge in the sediment container is discharged to the sludge drying container.

In some embodiments, the sediment container has a water inlet, and the wastewater recovery system further comprises: the two ends of the fourth pipeline are respectively communicated with the fifth pipeline and the water inlet, the fifth pipeline is used for introducing sewage to be treated, and the fourth pipeline is provided with a sixth on-off valve; the recovery method further comprises:

after the slag discharge is finished, the sixth on-off valve is in an on state so as to feed water into the slag settling container to remove the sludge;

after the flushing is carried out for the preset time, the fifth on-off valve is in an off state, and water continues to enter the sediment container so as to fill the sediment container with water;

after the water filling is finished, the fourth on-off valve is in an on state, and the fifth on-off valve and the sixth on-off valve are in an off state.

The sewage recovery system of the embodiment of the disclosure, through setting up the second heat exchanger, the comdenstion water that obtains after retrieving through the sewage evaporation carries out the heat transfer with pending sewage, can make latent heat after the sewage evaporation is retrieved fully utilize in pending sewage of retrieving to improve the temperature of pending sewage, thereby it forms vapor to accelerate sewage evaporation in first heat exchanger, can improve sewage treatment efficiency, and increase sewage recovery system's operating efficiency, reduce the energy consumption of device operation, the energy saving.

Drawings

In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and for those skilled in the art, other drawings can be obtained according to the drawings without inventive exercise.

FIG. 1 is a schematic block diagram of some embodiments of the disclosed wastewater recovery system.

Description of the reference numerals

1. A first heat exchanger; 11. a first inlet; 12. a first outlet; 13. a second inlet; 14. a second outlet; 15. a slag outlet;

2. a second heat exchanger; 21. a third inlet; 22. a third outlet; 23. a fourth inlet; 24. a fourth outlet;

3. a third heat exchanger; 31. a fifth inlet; 32. a fifth outlet; 33. a sixth inlet; 34. a sixth outlet;

4. a compressor; 41. an air inlet; 42. an exhaust port;

5. a liquid level detection section; 5', a gas-liquid separator; 6. a one-way valve; 7. a negative pressure pump;

71. a first on-off valve; 72. a second on-off valve; 73. a third shutoff valve; 74. a fourth shutoff valve; 75. a fifth on-off valve; 76. a sixth on-off valve; 77. a flow regulating valve; 78. an eighth on-off valve;

8. an exhaust valve; 9. a sediment container; 91. a seventh inlet; 92. a seventh outlet; 93. a water inlet; 10. a sludge drying container;

l1, a first pipeline; l2, a second pipeline; l3, a third pipeline; l4, a fourth pipeline; l5, a fifth pipeline; l6, a sixth pipeline; l7, a seventh pipeline; l8, an eighth pipeline; l9 and a ninth pipeline.

Detailed Description

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without any inventive step, are intended to be within the scope of the present disclosure.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

In the description of the present disclosure, it is to be understood that the terms "central," "lateral," "longitudinal," "front," "rear," "left," "right," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientations and positional relationships indicated in the drawings only for the convenience of description and simplicity of description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and therefore, are not to be construed as limiting the scope of the invention.

In the description of the present disclosure, it should be understood that the terms "first", "second", etc. are used to define the components, and are used only for convenience of distinguishing the corresponding components, and if not otherwise stated, the terms have no special meaning, and thus, should not be construed as limiting the scope of the present disclosure.

The present disclosure provides a wastewater recovery system, which can recycle pure water as a recovered product, for example, for industrial water evaporation, such as air conditioner condensate, or for other applications.

In order to better understand the embodiments of the present disclosure, the various line types and media designations in FIG. 1 are first described. The dotted lines represent coolant flow lines, and the solid lines represent sewage, steam and condensate flow lines. WS represents sewage, ZQ represents water vapor and condensed water, and WN represents sludge.

In some embodiments, as shown in fig. 1, a wastewater recovery system includes:

the first heat exchanger 1 is provided with a first inlet 11, a first outlet 12, a second inlet 13 and a second outlet 14, wherein the first inlet 11 is used for introducing a gaseous refrigerant, and the first outlet 12 is communicated with the first inlet 11 and used for discharging a liquid refrigerant formed by condensation and heat exchange of the gaseous refrigerant and sewage; the second inlet 13 is used for introducing sewage, and the second outlet 14 is used for discharging water vapor formed after the sewage and the gaseous refrigerant are evaporated and heat exchanged; and

the second heat exchanger 2 is provided with a third inlet 21, a third outlet 22, a fourth inlet 23 and a fourth outlet 24, the third inlet 21 is used for introducing condensed water formed by water vapor, and the third outlet 22 is communicated with the third inlet 21 and used for discharging the condensed water after heat exchange with the sewage to be recovered; the fourth inlet 23 is used for introducing sewage to be recovered, and the fourth outlet 24 is communicated with the fourth inlet 23 and the second inlet 13, so that the sewage subjected to heat exchange with condensed water is introduced into the first heat exchanger 1.

The first heat exchanger 1 is used for heat exchange between preheated sewage and gaseous refrigerant, and the sewage and the gaseous refrigerant are both subjected to phase change. The second heat exchanger 2 is used for realizing heat exchange between the condensed water and the sewage to be recovered so as to preheat the sewage to be recovered.

For example, the first heat exchanger 1 is a shell-and-tube heat exchanger, and includes a shell and a heat exchange tube, the heat exchange tube is installed in the shell, a refrigerant is introduced into the heat exchange tube, and sewage is introduced into the shell to increase the treatment capacity during sewage evaporation and increase the sewage recovery efficiency. The second heat exchanger 2 can be a plate heat exchanger, and two heat exchange channels can be arranged inside the second heat exchanger and respectively circulate condensed water and sewage to be treated.

Specifically, the second heat exchanger 2 is used for preheating sewage to be treated, the preheated sewage enters the first heat exchanger 1 through the second inlet 13 and exchanges heat with high-temperature gaseous refrigerant entering the first heat exchanger 1 through the first inlet 11, the sewage and the gaseous refrigerant all undergo phase change, the gaseous refrigerant condenses and exchanges heat to form liquid refrigerant, the refrigerant is discharged through the first outlet 12 to be circulated, the sewage absorbs heat released by condensation of the gaseous refrigerant, the heat is evaporated and exchanged to form vapor and the vapor is discharged through the second outlet 14, and the process can also be distillation.

After the vapor forms the comdenstion water at the condensation, get into second heat exchanger 2 through third import 21, pending sewage also gets into second heat exchanger 2 through fourth import 23 through fifth pipeline L5, and preheat pending sewage through the comdenstion water, the sewage after preheating is discharged through fourth export 24 and gets into first heat exchanger 1 through second import 13, discharge and get into third pipeline L3 through third export 22 after the comdenstion water heat transfer and derive, in order to realize the recovery of sewage.

This embodiment is through setting up second heat exchanger 2, and the comdenstion water that obtains after retrieving through the sewage evaporation carries out the heat transfer with pending sewage, can make latent heat after the sewage evaporation retrieves fully utilize in pending sewage to improve pending sewage's temperature, thereby it forms vapor to accelerate the evaporation of sewage in first heat exchanger 1, can improve sewage treatment efficiency, and increase sewage recovery system's operating efficiency, reduce the energy consumption of device operation, the energy saving.

In some embodiments, as shown in fig. 1, the wastewater recovery system further comprises: a compressor 4 and a third heat exchanger 3. Wherein the compressor 4 has an intake 41 and an exhaust 42; and a third heat exchanger 3. Wherein the third heat exchanger 3 has a fifth inlet 31, a fifth outlet 32, a sixth inlet 33 and a sixth outlet 34, the fifth inlet 31 is communicated with the first outlet 12, the fifth outlet 32 is communicated with the first inlet 11 through the compressor 4, the sixth inlet 33 is communicated with the second outlet 14, and the sixth outlet 34 is communicated with the sixth inlet 33 and the third inlet 21.

The third heat exchanger 3 is arranged between the first heat exchanger 1 and the second heat exchanger 2 and used for exchanging heat between liquid refrigerants and water vapor to realize phase change, the liquid refrigerants and the water vapor realize phase change, the water vapor is condensed and exchanged to form condensed water, the liquid refrigerants absorb heat generated by condensation and heat exchange and generate evaporation and heat exchange to form low-temperature and low-pressure gaseous refrigerants, the gaseous refrigerants with high temperature and high pressure are formed after being compressed by the compressor 4 and enter the first heat exchanger 1 through the first inlet 11 again.

For example, the third heat exchanger 3 may be a plate heat exchanger, and two heat exchange channels may be disposed inside the third heat exchanger to respectively circulate water vapor and liquid refrigerant.

Specifically, the liquid refrigerant discharged from the first outlet 12 of the first heat exchanger 1 enters the third heat exchanger 3 through the sixth pipeline L6 and the fifth inlet 31, undergoes evaporation and heat exchange with water vapor to form a low-temperature and low-pressure gaseous refrigerant, enters the air inlet 41 of the compressor 4 and is compressed, and the high-temperature and high-pressure gaseous refrigerant is discharged from the air outlet 42 of the compressor 4 and returns to the first heat exchanger 1 through the first inlet 11, so that the sixth pipeline L6 and the seventh pipeline L7 form a refrigerant circulation loop.

Meanwhile, the water vapor discharged from the second outlet 14 of the first heat exchanger 1 enters the third heat exchanger 3 through the eighth pipeline L8 and the sixth inlet 33, and after condensing and heat exchanging with the liquid refrigerant, condensed water is formed and enters the second heat exchanger 2 through the second pipeline L2 and the third inlet 21, so that the condensed water preheats the sewage to be recovered in the second heat exchanger 2.

This embodiment forms the comdenstion water through setting up third heat exchanger 3 and carrying out the condensation heat transfer to vapor, utilizes the heat that releases to make liquid refrigerant form gaseous state refrigerant among the condensation process simultaneously, realizes the cyclic utilization of refrigerant, make full use of the heat that the vapor condensation was given off, greatly increased sewage recovery system's operating efficiency, reduced the operation energy consumption.

In some embodiments, the wastewater recovery system further comprises: the first pipeline L1 and the second pipeline L2 are connected in parallel, the first ends of the first pipeline L1 and the second pipeline L2 are communicated with the sixth outlet 34, the second ends of the first pipeline L1 and the second pipeline L2 are communicated with the third inlet 21, the first pipeline L1 is used for guiding gas in condensed water, and the second pipeline L2 is internally provided with a gas-liquid separator 5'. The gas-liquid separator 5' is used for realizing gas-liquid separation of condensed water and storage of the condensed water.

The first pipeline L1 may be a capillary tube with a small diameter, and the inlet of the gas-liquid separator 5 'is communicated with the sixth outlet 34, and the outlet of the gas-liquid separator 5' is communicated with the third inlet 21. The condensed water enters the gas-liquid separator 5' and then undergoes gas-liquid separation, the non-condensed gas enters the first pipeline L1, and the liquid enters the second heat exchanger 2 through the third inlet 21 to preheat the sewage to be recovered.

This embodiment is through parallelly connected setting up first pipeline L1 and second pipeline L2 between second heat exchanger 2 and third heat exchanger 3 to set up vapour and liquid separator 5' on second pipeline L2, can in time separate out the noncondensable gas in the condensate water, prevent that gas from storing up in the pipeline and occupy the volume, in order to avoid blockking up the pipeline, can prevent that the noncondensable gas from influencing the process that sewage evaporation formed vapor, and improve the flow efficiency of liquid in the pipeline, improve sewage recovery efficiency.

In some embodiments, the wastewater recovery system further comprises: a liquid level detection unit 5 provided in the first pipeline L1 and configured to detect a liquid level of the condensed water in the first pipeline L1; and a first on-off valve 71 and a second on-off valve 72, both provided on the first pipeline L1, and respectively located on both sides of the liquid level detection part 5.

For example, the first and second on-off valves 71 and 72 may be manual valves or electrically controlled valves.

Since the first line L1 and the second line L2 are communicated, by providing the liquid level detecting part 5, the liquid level in the gas-liquid separator 5 'can be detected by utilizing the principle of the communicating vessel, so that the operating frequency of the later-mentioned negative pressure pump 7 is adjusted according to the amount of liquid stored in the gas-liquid separator 5', thereby adjusting the output amount of the condensed water. Moreover, when the liquid level detection unit 5 needs to be maintained, the first on-off valve 71 and the second on-off valve 72 are both in the off state, and the first pipeline L1 is independent of the second pipeline L2, so that the sewage treatment process is not affected.

The embodiment can detect the liquid level in the gas-liquid separator 5 'during the sewage treatment process by arranging the liquid level detection part 5, so as to adjust the output quantity of condensed water according to the liquid quantity stored in the gas-liquid separator 5'; moreover, in the case where the first and second on-off valves 71 and 72 are closed, maintenance and replacement of the liquid level detection part 5 are facilitated.

In one embodiment, the wastewater recovery system further comprises: a third pipeline L3 connected to the third outlet 22 for leading out condensed water; a negative pressure pump 7 provided on the third pipeline L3; and the exhaust valve 8 is arranged on the third pipeline L3 and positioned at the inlet of the negative pressure pump 7, and the exhaust valve 8 is communicated with the first pipeline L1 and used for exhausting gas in the condensed water in an open state.

The exhaust valve 8 is disposed at an inlet of the negative pressure pump 7, and the pressure is low, so that the noncondensable gas in the first pipeline L1 can smoothly flow toward the exhaust valve 8.

This embodiment is through setting up discharge valve 8 on third pipeline L3, can conveniently discharge the noncondensable gas in the pipeline in time, prevents that gas from storing up in the pipeline and taking up the volume to block up the pipeline, can prevent that noncondensable gas from influencing the process that sewage evaporation formed vapor, and improve the flow efficiency of liquid in the pipeline, improve sewage recovery efficiency.

In some embodiments, the wastewater recovery system further includes a connection pipe, and the exhaust valve 8 is in communication with the first pipeline L1 through the connection pipe.

For example, the connection pipe may be a capillary pipe, which is not shown in fig. 1 because the exhaust valve 8 is far away from the first pipeline L1.

This embodiment can conveniently realize the intercommunication between discharge valve 8 and the first pipeline L1 through setting up the connecting pipe, can reduce the requirement to the position relation between discharge valve 8 and the first pipeline L1 to set up discharge valve 8 more nimble.

In some embodiments, the wastewater recovery system further comprises: a third pipeline L3 connected to the third outlet 22 for leading out condensed water; and a negative pressure pump 7 provided on the third line L3 for maintaining a negative pressure in the first heat exchanger 1.

For example, the negative pressure pump 7 may be a negative pressure screw pump or the like.

This embodiment is through setting up negative pressure pump 7 on third pipeline L3, not only can provide power for the discharge of comdenstion water to carry the comdenstion water to the water spot, can also form the negative pressure in the system, can reduce the evaporating temperature of sewage, when making the temperature in the first heat exchanger 1 be less than the evaporating temperature under the ordinary pressure, sewage just can evaporate to vapor, has improved sewage recovery efficiency, and has reduced recovery system's energy consumption.

Moreover, through setting up the noncondensable gas of first pipeline L1 storage condensate water, can prevent that gas from getting into negative pressure pump 7 and causing the system negative pressure to become invalid.

In some embodiments, the negative pressure pump 7 is a variable frequency pump, and the operating frequency is configured to be adjusted according to the required amount of condensed water and/or the generated amount of condensed water.

The amount of the generated condensed water can be detected by the liquid level detection part 5 disposed on the first pipeline L1, and the liquid level detection part 5 can detect the liquid level of the gas-liquid separator 5 'to obtain the amount of the condensed water stored in the gas-liquid separator 5'.

The embodiment can increase the working frequency of the negative pressure pump 7 to meet the supply requirement of the condensed water when the demand of the external condensed water is large or the generation amount of the condensed water in the sewage recovery process is large; when the demand of external condensed water is small or the generation amount of the condensed water in the sewage recovery process is small, the working frequency of the negative pressure pump 7 is reduced, so that the operation energy consumption of the negative pressure pump 7 is reduced on the basis of meeting the supply demand of the condensed water.

In some embodiments, the wastewater recovery system further comprises: a third pipeline L3 connected to the third outlet 22 for leading out condensed water; and a check valve 6 provided on the third line L3 for allowing only one-way flow of the condensed water from the third outlet 22 along the third line L3.

This embodiment can prevent the condensate water from flowing reversely toward the second heat exchanger 2 by providing the check valve 6 in the third pipeline L3, and provide pressure guarantee for the system, prevent the external water or gas suction system from being caused by the increase of the external pressure or the stop of the negative pressure pump 7, and improve the safety of the recovery system.

In some embodiments, as shown in fig. 1, the first heat exchanger 1 further has a slag outlet 15, and the wastewater recovery system further comprises: a slag container 9 having a seventh inlet 91 and a seventh outlet 92, the seventh inlet 91 being connected to the slag outlet 15; and a sludge drying container 10 connected to the seventh outlet 92.

Wherein, the slag outlet 15 is arranged at the bottom of the first heat exchanger 1, and in the process of sewage treatment, the sewage in the first heat exchanger 1 can be deposited in the bottom area of the first heat exchanger 1 and enter the sediment container 9 under the action of gravity. In the process, in order to maintain the negative pressure of the system, the connection between the sediment container 9 and the sludge drying container 10 can be disconnected; after the sewage treatment is finished, the sludge in the sediment container 9 can enter the sludge drying container 10 for drying, and then is transported outside after drying.

In this embodiment, the sludge container 9 and the sludge drying container 10 are provided, so that the sludge in the first heat exchanger 1 can be collected after the sewage is recovered and treated as solid waste after drying, thereby preventing environmental pollution.

In some embodiments, the wastewater recovery system further comprises: a fourth shut-off valve 74 provided on the pipe between the slag hole 15 and the seventh inlet 91; and/or a fifth on-off valve 75 provided on the pipe between the seventh outlet 92 and the sludge drying container 10.

The fourth on-off valve 74 and the fifth on-off valve 75 may be manual valves or electric control valves to achieve the degree of automation of the sewage sludge treatment.

Specifically, in the process of sewage treatment, the fourth on-off valve 74 is in an on state, the fifth on-off valve 75 is in an off state, sludge at the bottom of the first heat exchanger 1 can enter the sediment container 9, the negative pressure requirement of the system can be maintained, the pressure in the first heat exchanger 1 is ensured to be constant, and the sewage recovery process is smoothly performed. After the sewage treatment is finished, the fourth on-off valve 74 is in an off state, and then the fifth on-off valve 75 is in an on state, so that the sludge in the sediment container 9 enters the sludge drying container 10 for drying, and meanwhile, the negative pressure in the system can be still maintained in the process.

In this embodiment, the fourth on-off valve 74 and/or the fifth on-off valve 75 are provided, so that the discharging and collecting processes of the sludge can be flexibly controlled, and the negative pressure environment in the system can be maintained in the process of discharging the sludge.

In some embodiments, the sediment container 9 has a water inlet 93, and the wastewater recovery system further comprises: and two ends of the fourth pipeline L4 are respectively communicated with the fifth pipeline L5 and the water inlet 93, the fifth pipeline L5 is used for introducing sewage to be treated, and the sixth on-off valve 76 is arranged on the fourth pipeline L4 so as to feed water into the sediment container 9 in a state that the sixth on-off valve 76 is switched on.

After the slag discharge is completed, the sixth on-off valve 76 may be turned on, so that the sewage introduced through the fifth pipeline L5 enters the sludge container 9 through the fourth pipeline L4 to be flushed, and the sewage and the sludge enter the sludge drying container 10 through the fifth on-off valve 75. After the preset time of flushing, the fifth on-off valve 75 is in an off state, and water continues to enter the sediment container 9, so that the sediment container 9 is filled with sewage to be treated, the sewage completely occupies the space in the sediment container 9, and after the fourth on-off valve 74 is switched on in the subsequent sewage treatment process, the negative pressure value in the first heat exchanger 1 is kept unchanged, and subsequent sediment is facilitated. After the water filling is completed, the fifth and sixth on-off

valves

75 and 76 may be turned off, and the fourth off-valve 74 may be turned on to maintain the system pressure for sewage recovery.

In the embodiment, after the sludge in the sludge container 9 is discharged into the sludge drying container 10, the sixth on-off valve 76 is opened to introduce the sewage to be treated so as to flush the sludge container 9, so that the sludge can be removed in time, and the sludge in the sludge container 9 is prevented from being gathered; moreover, after the sludge in the sediment container 9 is removed, the sediment container 9 can be filled with water in time, so that the sewage completely occupies the space in the sediment container 9, and after the fourth shut-off valve 74 is switched on in the subsequent sewage treatment process, the negative pressure value in the first heat exchanger 1 can be kept unchanged, and the subsequent sediment is facilitated.

One embodiment of the disclosed wastewater recovery system is given below in conjunction with FIG. 1.

The sewage recovery system comprises a first heat exchanger 1, a second heat exchanger 2, a third heat exchanger 3 and a compressor 4. The first heat exchanger 1 has a first inlet 11, a first outlet 12, a second inlet 13 and a second outlet 14, the second heat exchanger 2 has a third inlet 21, a third outlet 22, a fourth inlet 23 and a fourth outlet 24, and the third heat exchanger 3 has a fifth inlet 31, a fifth outlet 32, a sixth inlet 33 and a sixth outlet 34.

For the third heat exchanger 3, the fifth inlet 31 and the first outlet 12 are communicated through the sixth pipeline L6, the fifth outlet 32 and the fifth inlet 31 are communicated, and are communicated with the first inlet 11 through the compressor 4 in the seventh pipeline L7, the sixth inlet 33 is communicated with the second outlet 14 through the eighth pipeline L8, and the sixth outlet 34 is communicated with the sixth inlet 33 and is connected with the third inlet 21.

For the second heat exchanger 2, the third inlet 21 is connected with the sixth outlet 34, the third outlet 22 is communicated with the third inlet 21 and leads out the condensed water through the third pipeline L3, the fourth inlet 23 is connected with the fifth pipeline L5 to feed in the sewage to be recovered, and the fourth outlet 24 is communicated with the second inlet 13 through the ninth pipeline L9.

Wherein, the fifth pipeline L5 is provided with a flow regulating valve 77 for regulating the inflow of sewage. An exhaust valve 8, a negative pressure pump 7 and a one-way valve 6 are sequentially arranged on the third pipeline L3 along the discharge direction of the condensed water, and the exhaust valve 8 is used for discharging non-condensable gas in the condensed water when the exhaust valve is opened; the negative pressure pump 7 is used for providing power for the discharge of condensed water and providing negative pressure for the system to facilitate evaporation; the one-way valve 6 is used to prevent external gas or liquid from entering the system; the exhaust valve 8 is communicated with the first pipeline L1 for exhausting non-condensable gas in the condensed water in an open state.

A first pipeline L1 and a second pipeline L2 are arranged in parallel between the third inlet 21 of the second heat exchanger 2 and the sixth outlet 34 of the third heat exchanger 3, and a gas-liquid separator 5' is arranged in the second pipeline L2.

Optionally, the wastewater treatment system further comprises: the bottom of the first heat exchanger 1 is provided with a slag hole 15, the slag container 9 is provided with a seventh inlet 91, a seventh outlet 92 and a water inlet 93, the seventh inlet 91 is connected with the slag hole 15, the sludge drying container 10 is connected with the seventh outlet 92, and the water inlet 93 is connected to a fifth pipeline L5 through a fourth pipeline L4.

The sewage treatment part is provided with a plurality of valves, for example, a liquid level detection part 5 is arranged on the first pipeline L1, and a first on-off valve 71 and a second on-off valve 72 are respectively arranged on the first pipeline L1 and positioned at two sides of the liquid level detection part 5; a fourth shut-off valve 74 is arranged on a pipeline between the slag outlet 15 and the seventh inlet 91; a fifth on-off valve 75 is arranged on a pipeline between the seventh outlet 92 and the sludge drying container 10; a sixth on-off valve 76 is arranged on the fifth pipeline L5; an eighth on-off valve 78 is disposed on the third pipeline L3, and a third on-off valve 73 is disposed on the sixth pipeline L6.

The working principle of the sewage treatment device is as follows:

the second heat exchanger 2 is used for preheating sewage to be treated, the preheated sewage enters the first heat exchanger 1 through a ninth pipeline L9 and a second inlet 13 and exchanges heat with high-temperature gaseous refrigerant entering the first heat exchanger 1 through a first inlet 11, the sewage and the gaseous refrigerant all undergo phase change, the gaseous refrigerant is condensed and exchanged heat to form liquid refrigerant, the liquid refrigerant is discharged through a first outlet 12 to be circulated, the sewage absorbs heat released by condensation of the gaseous refrigerant, and the water vapor is evaporated and exchanged and is discharged through a second outlet 14.

The water vapor enters the third heat exchanger 3 through the eighth pipeline L8 and the sixth inlet 33, the liquid refrigerant enters the third heat exchanger 3 through the sixth pipeline L6 and the fifth inlet 31, and the water vapor exchanges heat with the liquid refrigerant. After the liquid refrigerant undergoes evaporation and heat exchange, a low-temperature and low-pressure gaseous refrigerant is formed, and enters the air inlet 41 of the compressor 4 to be compressed, and after the compression, a high-temperature and high-pressure gaseous refrigerant is discharged from the air outlet 42 of the compressor 4 and returns to the first heat exchanger 1 again through the seventh pipeline L7 and the first inlet 11, so that the sixth pipeline L6 and the seventh pipeline L7 form a refrigerant circulation loop. Meanwhile, the water vapor performs condensation heat exchange to form condensed water, and enters the second heat exchanger 2 through the second pipeline L2 and the third inlet 21.

Meanwhile, sewage to be treated also enters the second heat exchanger 2 through a fourth inlet 23 through a fifth pipeline L5, the sewage to be treated is preheated through condensed water, the preheated sewage is discharged through a fourth outlet 24 and enters the first heat exchanger 1 through a ninth pipeline L9 and a second inlet 13, and the condensed water is discharged through a third outlet 22 after heat exchange and enters a third pipeline L3 to be led out, so that the sewage is recovered.

Secondly, the present disclosure provides a recovery method based on the above-mentioned sewage recovery system, in some embodiments, including:

the sewage to be recovered and the condensed water recovered from the sewage are subjected to heat exchange through the second heat exchanger 2 so as to preheat the sewage to be recovered, and the condensed water is led out after heat exchange;

the preheated sewage and the gaseous refrigerant are subjected to heat exchange through the first heat exchanger 1, so that the gaseous refrigerant is condensed and subjected to heat exchange to form a liquid refrigerant, and the sewage is evaporated and subjected to heat exchange to form vapor so as to enter the second heat exchanger 2 after condensed water is formed.

This embodiment is through setting up second heat exchanger 2, and the comdenstion water that obtains after retrieving through the sewage evaporation carries out the heat transfer with pending sewage, can make latent heat after the sewage evaporation is retrieved fully utilize in pending sewage of retrieving to improve pending sewage's temperature, thereby form vapor with higher speed in the evaporation of sewage in first heat exchanger 1, can improve sewage treatment efficiency, and increase sewage recovery system's operating efficiency, reduce the energy consumption of device operation.

In some embodiments, the recycling methods of the present application further comprise:

the liquid refrigerant and the vapor exchange heat through the third heat exchanger 3, so that the liquid refrigerant is evaporated and exchanges heat to form a gaseous refrigerant, the gaseous refrigerant is compressed by the compressor 4 and then enters the first heat exchanger 1, and the vapor is condensed and exchanged heat to form condensed water which enters the second heat exchanger 2.

In some embodiments, a first pipeline L1 and a second pipeline L2 are connected in parallel between the second heat exchanger 2 and the third heat exchanger 3, the first pipeline L1 is used for containing gas in condensed water, a gas-liquid separator 5' is arranged on the second pipeline L2, a liquid level detection part 5 is arranged on the first pipeline L1, and a first on-off valve 71 and a second on-off valve 72 are respectively arranged on the first pipeline L1 at two sides of the liquid level detection part 5; the recovery method further comprises:

in the sewage recovery process, the first on-off valve 71 and the second on-off valve 72 are both in an on state;

when the liquid level detection member 5 requires maintenance, both the first on-off valve 71 and the second on-off valve 72 are in the off state.

The embodiment can timely separate the non-condensable gas in the condensed water, and the gas is positioned in the first pipeline L1, so that the gas is prevented from being accumulated in the main pipeline to occupy the volume and block the pipeline, the phenomenon that the non-condensable gas influences the process of evaporating sewage to form water vapor is prevented, the flowing efficiency of liquid in the pipeline is improved, and the sewage recovery efficiency is improved; moreover, in the case where the first and second on-off valves 71 and 72 are in the off state, the first line L1 can be made independent of the second line L2 without affecting the sewage treatment process.

In some embodiments, the wastewater recovery system further comprises: a third pipeline L3 for leading out the condensed water passing through the first heat exchanger 1; and a negative pressure pump 7 provided on the third pipeline L3; the recovery method of the present disclosure further comprises:

in the sewage recovery process, the working frequency of the negative pressure pump 7 is adjusted according to the demand load of the condensed water and/or the amount of the generated condensed water.

The amount of the condensed water generated can be detected by the liquid level detection part 5 disposed on the first pipeline L1, and the liquid level detection part 5 can detect the liquid level of the gas-liquid separator 5 'to obtain the amount of the condensed water stored in the gas-liquid separator 5'.

In some embodiments, the first heat exchanger 1 further has a slag outlet 15, and the wastewater recovery system further comprises: a slag container 9 having a seventh inlet 91 and a seventh outlet 92, the seventh inlet 91 being connected to the slag outlet 15; and a sludge drying container 10 connected to the seventh outlet 92; wherein, a fourth on-off valve 74 is arranged on the pipeline between the slag hole 15 and the seventh inlet 91, and a fifth on-off valve 75 is arranged on the pipeline between the seventh outlet 92 and the sludge drying container 10; the recovery method further comprises:

in the sewage recovery process, the fourth on-off valve 74 is put in an on state, and the fifth on-off valve 75 is put in an off state;

in the slag discharging process, the fourth shutoff valve 74 is in the off state, and the fifth shutoff valve 75 is in the on state, so that the sludge in the sludge container 9 is discharged to the sludge drying container 10.

In the sewage recovery process, the sludge at the bottom of the first heat exchanger 1 can enter the sediment container 9, the negative pressure requirement of the system can be kept, and the sewage recovery process can be smoothly carried out; moreover, the sludge in the sediment container 9 enters the sludge drying container 10 for drying, and meanwhile, the negative pressure in the system can be still maintained in the deslagging process.

In some embodiments, the sediment container 9 has a water inlet 93, and the wastewater recovery system further comprises: two ends of a fourth pipeline L4 are respectively communicated with a fifth pipeline L5 and a water inlet 93, the fifth pipeline L5 is used for introducing sewage to be treated, and a sixth on-off valve 76 is arranged on the fourth pipeline L4; the recovery method further comprises:

after the slag discharge is completed, the sixth on-off valve 76 is in an on state to feed water into the slag settling container 9 to remove sludge;

after the preset time of flushing, the fifth on-off valve 75 is in an off state, and water continues to enter the sediment container 9, so that the sediment container 9 is filled with water;

after the water filling is completed, the fourth shut-off valve 74 is put in the on state, and the fifth and sixth shut-off

valves

75, 76 are put in the off state.

This embodiment can open the sixth on-off valve 76 to introduce the sewage to be treated after the sludge in the sludge container 9 is discharged into the sludge drying container 10 to flush the sludge container 9, which can remove the sludge in time and prevent the sludge from accumulating in the sludge container 9. After the preset time of flushing, the fifth on-off valve 75 is in an off state, and water continues to enter the sediment container 9, so that the sediment container 9 is filled with water, and sewage completely occupies the space in the sediment container 9, and after the fourth on-off valve 74 is switched on in the subsequent sewage treatment process, the negative pressure value in the first heat exchanger 1 is kept unchanged, and the subsequent sediment treatment process is facilitated. After the completion of the water filling, the fifth and sixth on/off

valves

75 and 76 are turned off, and the fourth on/off valve 74 is turned on, so that the pressure in the system can be maintained to enter the sewage recovery process at any time.

Each of the on-off valves and the heat exchanger in the above embodiments of the present disclosure may be controlled by a Controller, which may be a general purpose Processor, a Programmable Logic Controller (PLC), a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable Logic device, a discrete Gate or transistor Logic device, a discrete hardware component, or any suitable combination thereof for performing the functions described in the present disclosure.

The above description is only exemplary of the present disclosure and is not intended to limit the present disclosure, and any modification, equivalent replacement, or improvement made within the spirit and principle of the present disclosure should be included in the scope of the present disclosure.

Claims

1. A wastewater recovery system, comprising:

the first heat exchanger (1) is provided with a first inlet (11), a first outlet (12), a second inlet (13) and a second outlet (14), the first inlet (11) is used for introducing a gaseous refrigerant, and the first outlet (12) is communicated with the first inlet (11) and used for discharging a liquid refrigerant formed by condensation and heat exchange of the gaseous refrigerant and sewage; the second inlet (13) is used for introducing sewage, and the second outlet (14) is used for discharging water vapor formed after the sewage and the gaseous refrigerant are evaporated and heat exchanged; and

the second heat exchanger (2) is provided with a third inlet (21), a third outlet (22), a fourth inlet (23) and a fourth outlet (24), the third inlet (21) is used for introducing condensed water formed by water vapor, and the third outlet (22) is communicated with the third inlet (21) and is used for discharging the condensed water after heat exchange with the sewage to be recovered; the fourth inlet (23) is used for introducing sewage to be recovered, and the fourth outlet (24) is communicated with the fourth inlet (23) and the second inlet (13) and is used for introducing the sewage subjected to heat exchange with the condensed water into the first heat exchanger (1).

2. The wastewater recovery system of claim 1, further comprising:

a compressor (4); and

the third heat exchanger (3) is provided with a fifth inlet (31), a fifth outlet (32), a sixth inlet (33) and a sixth outlet (34), the fifth inlet (31) is communicated with the first outlet (12), the fifth outlet (32) is communicated with the first inlet (11) through the compressor (4), the sixth inlet (33) is communicated with the second outlet (14), the sixth outlet (34) is communicated with the sixth inlet (33) and the third inlet (21), and the third heat exchanger (3) is used for exchanging heat between liquid refrigerant and water vapor to achieve phase change.

3. The wastewater recovery system of claim 2, further comprising: the first pipeline (L1) and the second pipeline (L2) are connected in parallel, the first ends of the first pipeline (L1) and the second pipeline (L2) are communicated with the sixth outlet (34), the second ends of the first pipeline (L1) and the second pipeline (L2) are communicated with the third inlet (21), the first pipeline (L1) is used for containing gas in the condensed water, and a gas-liquid separator (5') is arranged in the second pipeline (L2).

4. The wastewater recovery system of claim 3, further comprising:

a liquid level detection unit (5) provided in the first line (L1) and configured to detect a liquid level of the condensed water in the first line (L1); and

and the first on-off valve (71) and the second on-off valve (72) are arranged on the first pipeline (L1) and are respectively positioned on two sides of the liquid level detection component (5).

5. The wastewater recovery system of claim 3, further comprising:

-a third line (L3) connected to said third outlet (22) for leading away said condensed water;

a negative pressure pump (7) arranged on the third pipeline (L3); and

and the exhaust valve (8) is arranged on the third pipeline (L3) and is positioned at an inlet of the negative pressure pump (7), and the exhaust valve (8) is communicated with the first pipeline (L1) and is used for exhausting gas in the condensed water in an opening state.

6. The effluent recovery system according to claim 5, further comprising a connecting pipe through which said discharge valve (8) communicates with said first conduit (L1).

7. The wastewater recovery system of claim 1, further comprising:

-a third line (L3) connected to said third outlet (22) for leading away said condensed water; and

and the negative pressure pump (7) is arranged on the third pipeline (L3) and is used for keeping the negative pressure in the first heat exchanger (1).

8. Sewage recovery system according to claim 7, wherein the negative pressure pump (7) is a variable frequency pump and the operating frequency is configured to be adjusted according to the amount of condensate demand and/or condensate production.

9. The wastewater recovery system of claim 1, further comprising:

a non-return valve (6) arranged on the third line (L3) for allowing only a non-return flow of the condensed water from the third outlet (22) along the third line (L3).

10. The effluent recovery system according to any one of claims 1 to 9 wherein said first heat exchanger (1) further has a slag outlet (15), said effluent recovery system further comprising:

a slag container (9) having a seventh inlet (91) and a seventh outlet (92), said seventh inlet (91) being connected to said slag outlet (15); and

a sludge drying container (10) connected with the seventh outlet (92).

11. The wastewater recovery system of claim 10, further comprising:

the fourth shutoff valve (74) is arranged on a pipeline between the slag outlet (15) and the seventh inlet (91); and/or

And the fifth on-off valve (75) is arranged on a pipeline between the seventh outlet (92) and the sludge drying container (10).

12. The wastewater recovery system according to claim 10, wherein the sludge container (9) has a water inlet (93), the wastewater recovery system further comprising:

and the two ends of the fourth pipeline (L4) are respectively communicated with the fifth pipeline (L5) and the water inlet (93), the fifth pipeline (L5) is used for introducing sewage to be treated, and a sixth on-off valve (76) is arranged on the fourth pipeline (L4) so as to feed water into the sediment container (9) in a state that the sixth on-off valve (76) is switched on.

13. A recycling method based on the sewage recycling system according to any one of claims 1 to 12, comprising:

the sewage to be recovered and the condensed water recovered from the sewage are subjected to heat exchange through the second heat exchanger (2) so as to preheat the sewage to be recovered, and the condensed water is led out after heat exchange;

the preheated sewage and the gaseous refrigerant are subjected to heat exchange through the first heat exchanger (1), so that the gaseous refrigerant is condensed and subjected to heat exchange to form a liquid refrigerant, and the sewage is evaporated and subjected to heat exchange to form steam so as to enter the second heat exchanger (2) after condensed water is formed.

14. The recycling method according to claim 13, further comprising:

the liquid refrigerant and the water vapor are subjected to heat exchange through the third heat exchanger (3) so that the liquid refrigerant is evaporated and subjected to heat exchange to form a gaseous refrigerant, the gaseous refrigerant is compressed by the compressor (4) and then enters the first heat exchanger (1), and the water vapor is condensed and subjected to heat exchange to form condensed water which enters the second heat exchanger (2).

15. The recycling method according to claim 14, wherein a first pipeline (L1) and a second pipeline (L2) are connected in parallel between the second heat exchanger (2) and the third heat exchanger (3), the first pipeline (L1) is used for containing gas in the condensed water, a gas-liquid separator (5') is arranged on the second pipeline (L2), a liquid level detection component (5) is arranged on the first pipeline (L1), and a first on-off valve (71) and a second on-off valve (72) are respectively arranged on the first pipeline (L1) and at two sides of the liquid level detection component (5); the recovery method further comprises:

in the sewage recovery process, the first on-off valve (71) and the second on-off valve (72) are both in an on state;

when the liquid level detection member (5) requires maintenance, both the first on-off valve (71) and the second on-off valve (72) are in an off state.

16. The recycling method according to claim 13, wherein the wastewater recycling system further comprises: a third line (L3) for discharging the condensed water passing through the first heat exchanger (1); and a negative pressure pump (7) arranged on the third pipeline (L3); the recovery method further comprises:

and in the sewage recovery process, the working frequency of the negative pressure pump (7) is adjusted according to the demand load of the condensed water and/or the amount of the generated condensed water.

17. A recovery method according to any of claims 13 to 16, characterized in that said first heat exchanger (1) further has a tap hole (15), said effluent recovery system further comprising: a slag container (9) having a seventh inlet (91) and a seventh outlet (92), said seventh inlet (91) being connected to said slag outlet (15); and a sludge drying container (10) connected to the seventh outlet (92); a fourth on-off valve (74) is arranged on a pipeline between the slag outlet (15) and the seventh inlet (91), and a fifth on-off valve (75) is arranged on a pipeline between the seventh outlet (92) and the sludge drying container (10); the recovery method further comprises:

in the sewage recovery process, the fourth on-off valve (74) is in an on state, and the fifth on-off valve (75) is in an off state;

in the slag discharging process, the fourth on-off valve (74) is in an off state, and the fifth on-off valve (75) is in an on state, so that the sludge in the sediment container (9) is discharged to the sludge drying container (10).

18. A recovery method according to claim 17, characterized in that the sludge container (9) has a water inlet (93), the effluent recovery system further comprising: two ends of the fourth pipeline (L4) are respectively communicated with a fifth pipeline (L5) and the water inlet (93), the fifth pipeline (L5) is used for introducing sewage to be treated, and a sixth on-off valve (76) is arranged on the fourth pipeline (L4); the recovery method further comprises:

after the slag discharge is finished, the sixth on-off valve (76) is in an on state to feed water into the slag settling container (9) to remove sludge;

after the flushing is carried out for the preset time, the fifth on-off valve (75) is in an off state, and water continues to enter the sediment container (9) so that the sediment container (9) is filled with water;

after the water filling is completed, the fourth shut-off valve (74) is put in an on state, and the fifth shut-off valve (75) and the sixth shut-off valve (76) are put in an off state.