Two-stage heat pump sewage water extraction system and method

Abstract

The present application relates to a kind of two-stage heat pump sewage extraction water system and method. The energy consumption of extracting water from sewage by distillation method is large. The present application includes atmospheric condenser, vacuum condenser, sewage evaporator, steam evaporator, atmospheric distiller and vacuum distiller, atmospheric condenser is located in atmospheric distiller, vacuum condenser is located in vacuum distiller;Atmospheric condenser is connected to vacuum condenser, and then branch is connected to sewage evaporator and steam evaporator, and then combined back to atmospheric condenser;Atmospheric distiller and vacuum distiller are combined to connect steam evaporator;Atmospheric distiller is connected to vacuum distiller, and then connected to sewage evaporator. The present application recovers the steam discharged from atmospheric distiller and vacuum distiller and the heat carried by sewage, as the heat source of steam evaporator and sewage evaporator, and heats and distills sewage through atmospheric condenser and vacuum condenser, which can effectively reduce the temperature discharge and reduce the operation cost of extracting water from sewage by distillation method.

Description

TECHNICAL FIELD

[0001] The present application relates to the sewage treatment technical field, specifically relates to a two-stage heat pump sewage extraction reclaimed water system and method. BACKGROUND

[0002] Reclaimed water refers to the water quality between water supply and drainage after sewage is properly treated, which can be used for washing vehicles, flushing toilets, greening irrigation, spraying roads and other occasions with low water quality requirements. The periodic cleaning of rail trains can use reclaimed water, which can greatly reduce the cleaning water cost. Extracting reclaimed water from sewage can greatly improve the utilization efficiency of water resources, alleviate the lack of water resources, and improve the ecological benefits.

[0003] At present, the preparation process of the reclaimed water system is mainly through three-stage treatment of sewage to meet the reclaimed water quality requirements for recycling. The first-stage treatment mainly uses physical treatment method to remove the suspended solid pollutants in the sewage; the second-stage treatment mainly removes the organic pollutants in the sewage; and the third-stage treatment mainly removes the soluble inorganic substances in the sewage. The methods of the three-stage treatment process mainly include distillation method, activated carbon adsorption method, reverse osmosis method, ion exchange method, ozone oxidation method, coagulation sedimentation method, and electrodialysis method. Among them, the distillation method can extract pure water from sewage, and impurities such as salt and oil with a boiling point higher than water will remain in the residual liquid. The reclaimed water prepared by the distillation method has good water quality and can meet the reclaimed water quality requirements. However, the current process of extracting reclaimed water from sewage by distillation method needs to provide a large amount of heat energy to the system to separate the pure water from the residual liquid, and the large amount of heat carried by the residual liquid cannot be recycled, which not only causes warm discharge, but also causes great energy waste.

[0004] Therefore, new measures need to be proposed to overcome the above problems. SUMMARY

[0005] The purpose of the present application is to provide a two-stage heat pump sewage extraction reclaimed water system and method to solve the problem of high energy consumption in the current process of extracting reclaimed water from sewage by distillation method.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0007] The two-stage heat pump sewage extraction reclaimed water system comprises a normal-pressure condenser, a vacuum condenser, a sewage evaporator, a steam evaporator, a normal-pressure distiller and a vacuum distiller, the normal-pressure condenser is located in the normal-pressure distiller, and the vacuum condenser is located in the vacuum distiller.

[0008] The atmospheric condenser is connected to the vacuum condenser, and then branched to the sewage evaporator and the steam evaporator, and then combined to return to the atmospheric condenser, forming a heat pump system.

[0009] The atmospheric distiller and the vacuum distiller are combined to be connected to the steam evaporator, forming a reclaimed water system.

[0010] The atmospheric distiller is connected to the vacuum distiller, and then connected to the sewage evaporator, forming a sewage system.

[0011] Further, in the heat pump system, the refrigerant outlet of the atmospheric condenser is connected to the refrigerant inlet of the vacuum condenser through a first communication pipe.

[0012] Further, in the heat pump system, the refrigerant outlet of the vacuum condenser is connected to an expansion valve, and the expansion valve is branched to the refrigerant inlets of the sewage evaporator and the steam evaporator.

[0013] Further, in the heat pump system, the refrigerant outlets of the sewage evaporator and the steam evaporator are combined to be connected to the refrigerant inlet of a compressor, and the refrigerant outlet of the compressor is connected to the refrigerant inlet of the atmospheric condenser.

[0014] Further, in the reclaimed water system, the top of the atmospheric distiller has an atmospheric distiller steam outlet, and the top of the vacuum distiller has a vacuum distiller steam outlet, both of which are connected to the steam inlet of the steam evaporator.

[0015] Further, in the reclaimed water system, the condensate outlet of the steam evaporator is connected to a reclaimed water outlet.

[0016] Further, in the sewage system, the sewage outlet of the atmospheric distiller is connected to the sewage inlet of the vacuum distiller through a second communication pipe, and the sewage outlet of the vacuum distiller is connected to the sewage inlet of the sewage evaporator.

[0017] Further, in the sewage system, the sewage inlet of the atmospheric distiller is connected to the inlet of the secondary treated sewage.

[0018] Further, in the sewage system, the sewage outlet of the sewage evaporator is connected to a sewage outlet.

[0019] In another aspect, a two-stage heat pump sewage extraction reclaimed water method is provided, which is based on the implementation of the system and includes:

[0020] The sewage discharged from the atmospheric distiller is distilled again as raw water in the vacuum distiller;

[0021] The sewage discharged by the vacuum distiller enters the sewage evaporator as a heat source to release heat;

[0022] The refrigerant of the atmospheric condenser enters the vacuum condenser, and then enters the sewage evaporator and the steam evaporator to exchange heat, and is combined and returned to the atmospheric condenser;

[0023] The steam discharged by the atmospheric distiller steam outlet and the vacuum distiller steam outlet enters the steam evaporator after being mixed, and the middle water is obtained after releasing heat, and is discharged through the middle water discharge outlet.

[0024] Compared with the prior art, the beneficial effects of the present application are as follows:

[0025] The present application provides a two-stage heat pump sewage extraction middle water system and method, which recovers the heat carried by the steam and sewage discharged by the atmospheric distiller and the vacuum distiller, uses the steam and sewage as the heat source of the steam evaporator and the sewage evaporator respectively, and sequentially heats and distills the sewage after two-stage treatment through the atmospheric condenser and the vacuum condenser, so as to effectively reduce the temperature discharge and reduce the operation cost of extracting middle water from sewage by distillation method. After two-stage distillation by the atmospheric distiller and the vacuum distiller, the characteristics of changing the boiling point of substances by vacuum can be fully utilized, the energy is utilized in stages, and the operation of the sewage extraction middle water system is more efficient. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings of other embodiments can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 is a system composition diagram of the present application.

[0028] In the figure, the identification is:

[0029] 1-atmospheric condenser, 2-vacuum condenser, 3-expansion valve, 4-sewage evaporator, 5-steam evaporator, 6-compressor, 7-atmospheric distiller, 8-vacuum distiller, 9-atmospheric distiller steam outlet, 10-vacuum distiller steam outlet, 11-first communication pipe, 12-sewage inlet after two-stage treatment, 13-sewage discharge outlet, 14-middle water discharge outlet, 15-second communication pipe. DETAILED DESCRIPTION

[0030] For the purpose of promoting an understanding of the application, the application will now be described in greater detail with reference to the figures. The preferred embodiments of the application are illustrated in the figures. However, the application can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the application to those skilled in the art.

[0031] In the description of the present application, it should be noted that unless specifically stated and limited otherwise, the terms "connected", "connected", "provided" and the like should be understood broadly, for example, they can be fixedly connected, provided, or detachably connected, provided, or integrally connected, provided. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0032] At the same time, in the description of the present application, the terms "first", "second" and the like are only used for differentiation and description, and cannot be understood as indicating or implying relative importance. Of course, such objects can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0033] The present application provides a two-stage heat pump sewage extraction water system, which can be used to extract water from sewage based on distillation method, using heat pump technology, recovering the heat of steam produced by the evaporator and the heat in the sewage through the condenser, and supplying the condenser again to provide sewage distillation water, thereby reducing the operation cost of sewage extraction water.

[0034] The heat pump is a system that only needs to consume a small amount of electric energy to realize the transfer of heat from a low-temperature heat source to a high-temperature heat source. The heat extracted from the sewage and the steam by the condenser of the heat pump can supply the heat required for the evaporation of pure water in the sewage in the evaporator, and the evaporated pure water and the sewage can release heat again in the condenser, thereby fully recycling energy. The combination of the heat pump circulation system and the sewage extraction water system can realize efficient extraction of water from sewage by using only a small amount of electric energy, which will greatly improve the economic efficiency of the system.

[0035] As shown in Figure 1 , the two-stage heat pump sewage extraction water system includes a normal pressure condenser 1, a vacuum condenser 2, an expansion valve 3, a sewage evaporator 4, a steam evaporator 5, a compressor 6, a normal pressure distiller 7, a vacuum distiller 8, and various necessary pipes, including air pipes, water pipes and refrigerant pipes. The normal pressure condenser 1 is located in the normal pressure distiller 7, and the vacuum condenser 2 is located in the vacuum distiller 8.

[0036] The two-stage heat pump sewage extraction water system includes three subsystems, which are:

[0037] 1. Heat pump system:

[0038] The atmospheric condenser 1 is connected to the vacuum condenser 2, and then branched to the sewage evaporator 4 and the steam evaporator 5, and then combined to return to the atmospheric condenser 1, forming a heat pump system.

[0039] In the heat pump system, the refrigerant outlet of the atmospheric condenser 1 is connected to the refrigerant inlet of the vacuum condenser 2 through the first communication pipe 11. The refrigerant outlet of the vacuum condenser 2 is connected to the expansion valve 3, and the expansion valve 3 is branched to the refrigerant inlet of the sewage evaporator 4 and the refrigerant inlet of the steam evaporator 5. The refrigerant outlet of the sewage evaporator 4 and the refrigerant outlet of the steam evaporator 5 are combined to the refrigerant inlet of the compressor 6, and the refrigerant outlet of the compressor 6 is connected to the refrigerant inlet of the atmospheric condenser 1.

[0040] 2. The middle water system:

[0041] The atmospheric distiller 7 and the vacuum distiller 8 are combined to the steam evaporator 5, forming a middle water system.

[0042] In the middle water system, the top of the atmospheric distiller 7 has an atmospheric distiller steam outlet 9, and the top of the vacuum distiller 8 has a vacuum distiller steam outlet 10, both of which are connected to the steam inlet of the steam evaporator 5. The condensate outlet of the steam evaporator 5 is connected to the middle water outlet 14.

[0043] 3. The sewage system:

[0044] The atmospheric distiller 7 is connected to the vacuum distiller 8, and then connected to the sewage evaporator 4, forming a sewage system.

[0045] In the sewage system, the sewage outlet of the atmospheric distiller 7 is connected to the sewage inlet of the vacuum distiller 8 through the second communication pipe 15, and the sewage outlet of the vacuum distiller 8 is connected to the sewage inlet of the sewage evaporator 4. In the sewage system, the sewage inlet of the atmospheric distiller 7 is connected to the secondary treated sewage inlet 12. The sewage outlet of the sewage evaporator 4 is connected to the sewage outlet 13.

[0046] In the above-mentioned double-stage heat pump sewage extraction middle water system, at least one vacuum distiller 8 is provided, and multiple vacuum distillers 8 can be provided according to actual needs and installed in parallel to increase heat exchange efficiency and distillation efficiency.

[0047] On the other hand, the application also provides a double-stage heat pump sewage extraction middle water method, which is implemented based on the above-mentioned double-stage heat pump sewage extraction middle water system, and during system operation:

[0048] ① The sewage discharged by the atmospheric distiller 7 enters the vacuum distiller 8 as raw water and is distilled again.

[0049] ② The sewage discharged from the vacuum distiller 8 is used as heat source and enters the sewage evaporator 4 to release heat;

[0050] ③ The refrigerant from the atmospheric condenser 1 enters the vacuum condenser 2, and then enters the sewage evaporator 4 and the steam evaporator 5 to exchange heat, and is returned to the atmospheric condenser 1;

[0051] ④ The steam discharged from the atmospheric distiller steam outlet 9 and the vacuum distiller steam outlet 10 is mixed and enters the steam evaporator 5 to release heat and obtain the reclaimed water, which is discharged through the reclaimed water outlet 14.

[0052] The operation process of the above-mentioned double-stage heat pump sewage reclaimed water extraction system is as follows:

[0053] 1. Heat pump cycle:

[0054] The compressor 6 is started, the refrigerant is heated and pressurized in the compressor 6, enters the atmospheric condenser 1, releases heat to the sewage in the atmospheric distiller 7, and then enters the vacuum condenser 2 through the first communication pipe 11 to release heat to the sewage discharged from the atmospheric distiller 7 again, flows into the expansion valve 3 for adiabatic expansion, and then enters the sewage evaporator 4 and the steam evaporator 5. In the sewage evaporator 4, the heat from the sewage discharged from the vacuum distiller 8 is absorbed, and in the steam evaporator 5, the heat from the steam discharged from the atmospheric distiller steam outlet 9 and the vacuum distiller steam outlet 10 is absorbed, and then enters the compressor 6 again to complete the cycle of the heat pump system.

[0055] 2. Reclaimed water extraction:

[0056] The sewage treated by two-stage treatment in the atmospheric distiller 7 absorbs the heat of the refrigerant in the atmospheric condenser 1 to evaporate, and is discharged through the atmospheric distiller steam outlet 9. The sewage discharged from the atmospheric distiller 7 enters the vacuum distiller 8, absorbs the heat of the refrigerant in the vacuum condenser 2 to evaporate, and is discharged through the vacuum distiller steam outlet 10. The steam discharged from the atmospheric distiller steam outlet 9 and the vacuum distiller steam outlet 10 is mixed and enters the steam evaporator 5 to release heat and condense into reclaimed water, which is sent to the building reclaimed water system through the reclaimed water outlet 14 for use.

[0057] 3. Sewage discharge:

[0058] The sewage treated by two-stage treatment absorbs the heat of the refrigerant in the atmospheric condenser 1 in the atmospheric distiller 7, of which the pure water is discharged in the form of steam through the atmospheric distiller steam outlet 9, and the remaining sewage enters the vacuum distiller 8 through the communication pipe 15, absorbs the heat of the refrigerant in the vacuum condenser 2 to evaporate again, of which the pure water is discharged in the form of steam through the vacuum distiller steam outlet 10, and the remaining sewage flows into the sewage evaporator 4 to release heat to the refrigerant, and is discharged through the sewage outlet 13.

[0059] The double-stage heat pump sewage water extraction system adopts heat pump circulation technology, recycles the heat of steam and sewage discharged from the normal pressure distiller 7 and the vacuum distiller 8, takes the steam and sewage as the heat source of the steam evaporator 5 and the sewage evaporator 4 respectively, and sequentially heats and distills the sewage treated by two-stage treatment through the normal pressure condenser 1 and the vacuum condenser 2, so that the temperature discharge can be reduced, and the operation cost of extracting water from sewage by distillation method can be effectively reduced. After two-stage distillation of the normal pressure distiller 7 and the vacuum distiller 8, the energy can be used in stages by fully utilizing the feature of changing the boiling point of substances by vacuum, so that the operation of the sewage water extraction system is more efficient, the water yield is about 16% higher than that of the ordinary system, and the cost is reduced by about 22%, so that the operation of the sewage water extraction system is more efficient.

[0060] The above application of specific examples is used to illustrate the present application, and is only used to help understanding the present application, and does not limit the present application. According to the idea of the present application, a person skilled in the art can make several simple deductions, deformations or substitutions.

Claims

1. A double-stage heat pump sewage extraction reclaimed water system, characterized in that: the double-stage heat pump sewage extraction reclaimed water system comprises an atmospheric condenser (1), a vacuum condenser (2), a sewage evaporator (4), a steam evaporator (5), an atmospheric distiller (7) and a vacuum distiller (8), the atmospheric condenser (1) is located in the atmospheric distiller (7), and the vacuum condenser (2) is located in the vacuum distiller (8); the atmospheric condenser (1) is connected to the vacuum condenser (2), and then branched to the sewage evaporator (4) and the steam evaporator (5), and then combined back to the atmospheric condenser (1), to form a heat pump system; the atmospheric distiller (7) and the vacuum distiller (8) are combined and connected to the steam evaporator (5), to form a reclaimed water system; the atmospheric distiller (7) is connected to the vacuum distiller (8), and then connected to the sewage evaporator (4), to form a sewage system; in the heat pump system, the refrigerant outlet of the atmospheric condenser (1) is connected to the refrigerant inlet of the vacuum condenser (2) through a first communication pipe (11); in the heat pump system, the refrigerant outlet of the vacuum condenser (2) is connected to an expansion valve (3), and the expansion valve (3) is branched to the refrigerant inlets of the sewage evaporator (4) and the steam evaporator (5); in the heat pump system, the refrigerant outlets of the sewage evaporator (4) and the steam evaporator (5) are combined and connected to the refrigerant inlet of a compressor (6), and the refrigerant outlet of the compressor (6) is connected back to the refrigerant inlet of the atmospheric condenser (1); in the reclaimed water system, the top of the atmospheric distiller (7) is provided with an atmospheric distiller steam outlet (9), the top of the vacuum distiller (8) is provided with a vacuum distiller steam outlet (10), and the atmospheric distiller steam outlet (9) and the vacuum distiller steam outlet (10) are both connected to the steam inlet of the steam evaporator (5); in the reclaimed water system, the condensate water outlet of the steam evaporator (5) is connected to a reclaimed water discharge outlet (14); in the sewage system, the sewage outlet of the atmospheric distiller (7) is connected to the sewage inlet of the vacuum distiller (8) through a second communication pipe (15), and the sewage outlet of the vacuum distiller (8) is connected to the sewage inlet of the sewage evaporator (4).

2. The double-stage heat pump sewage extraction reclaimed water system according to claim 1, characterized in that: in the sewage system, the sewage inlet of the atmospheric distiller (7) is connected to a twice-treated sewage inlet (12).

3. The double-stage heat pump sewage extraction reclaimed water system according to claim 2, characterized in that: in the sewage system, the sewage outlet of the sewage evaporator (4) is connected to a sewage discharge outlet (13).

4. A double-stage heat pump sewage extraction reclaimed water method, characterized in that: the method is implemented based on the system according to any one of claims 1-3, comprising: the sewage discharged from the atmospheric distiller (7) is distilled again as raw water in the vacuum distiller (8). The sewage discharged from the vacuum distiller (8) is used as heat source and enters the sewage evaporator (4) to release heat; The refrigerant of the atmospheric condenser (1) enters the vacuum condenser (2), and then is branched to enter the sewage evaporator (4) and the steam evaporator (5) respectively to exchange heat, and the exchanged refrigerant is combined and returned to the atmospheric condenser (1); The steam discharged from the atmospheric distiller steam outlet (9) and the vacuum distiller steam outlet (10) is mixed and enters the steam evaporator (5) to release heat, and the obtained water is discharged through the water outlet (14).

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