Anaerobic sewage treatment system

Abstract

The utility model provides an anaerobic sewage treatment system which comprises a water collecting tank capable of receiving industrial sewage, a degradation tank capable of carrying out anaerobic degradation on the industrial sewage, a wastewater tank capable of receiving the industrial sewage subjected to anaerobic degradation, a water source heat pump and a sewage network pipe for sewage discharge, and the water source heat pump comprises a compressor, an air cooler, an expansion valve and an evaporator. The air cooler is provided with a first branch and a second branch which can perform heat exchange, the evaporator is provided with a third branch and a fourth branch which can perform heat exchange, and the compressor, the first branch, the expansion valve and the third branch are in fluid communication in sequence and form a first loop for a refrigerant to circularly flow; the water collecting tank, the second branch and the degradation tank are in fluid communication in sequence so as to heat industrial sewage entering the degradation tank; and the degradation tank, the wastewater tank, the fourth branch and the sewage network pipe are sequentially in fluid communication so as to recover heat of industrial sewage in the wastewater tank. When the anaerobic sewage treatment system is used for heating, only less energy needs to be paid to the water source heat pump.

Description

Technical Field

[0001] The utility model relates to the field of sewage treatment, in particular to an anaerobic sewage treatment system. Background Art

[0002] Biogas in biomass energy is an ideal renewable energy source in industrial production. Industrial wastewater can be made into biogas after anaerobic wastewater treatment. The main component of biogas is methane, which can replace the natural gas used in front-end production and effectively reduce the use of natural gas.

[0003] Anaerobic sewage treatment technology is an efficient sewage treatment method in which organic matter in sewage is decomposed, metabolized and digested by anaerobic bacteria under anaerobic conditions, which greatly reduces the organic matter content in sewage and produces biogas. The anaerobic degradation process of high molecular organic matter in sewage can be roughly divided into three stages: hydrolysis stage, acid production stage and methane production stage.

[0004] However, the anaerobic degradation process of organic matter in sewage is affected by many factors such as ambient temperature, pH value, C / N ratio and nitrogen inhibition. Among them, temperature is the most important factor that dominates anaerobic degradation, and the reaction temperature is best maintained at 35°C. There are large temperature differences in various regions in my country. If the anaerobic degradation tank is not heated in the northern region in winter, the anaerobic reaction will be in a hysteresis stage. However, traditional anaerobic sewage treatment systems generally use steam heating or electric heating to maintain the temperature of sewage during anaerobic degradation. The total calorific value of the biogas produced after anaerobic degradation of sewage is less than the energy required. Utility Model Content

[0005] In view of the above technical problems, the purpose of the utility model is to provide an anaerobic sewage treatment system which can effectively reduce the energy required for heating sewage.

[0006] In order to achieve the above-mentioned purpose, the utility model provides the following technical solutions: an anaerobic sewage treatment system, comprising a water collection tank capable of receiving industrial sewage, a degradation tank capable of anaerobic degradation of industrial sewage, a wastewater tank capable of receiving industrial sewage after anaerobic degradation, a water source heat pump and a sewage network pipe for sewage discharge, the water source heat pump comprising a compressor, an air cooler, an expansion valve and an evaporator, the air cooler having a first branch and a second branch capable of heat exchange, the evaporator having a third branch and a fourth branch capable of heat exchange, the compressor, the first branch, the expansion valve and the third branch being fluidly connected in sequence and forming a first loop for circulating refrigerant; the water collection tank, the second branch and the degradation tank being fluidly connected in sequence to heat the industrial sewage entering the degradation tank; the degradation tank, the wastewater tank, the fourth branch and the sewage network pipe being fluidly connected in sequence to recover the heat of the industrial sewage in the wastewater tank.

[0007] In the above technical solution, preferably, the anaerobic sewage treatment system also includes a solar water heater, a heat exchanger and a circulation pump. The heat exchanger is arranged in the water collection tank. The solar water heater includes a water outlet and a water inlet of the water heater. The water outlet of the water heater, the heat exchanger and the water inlet of the electric water heater are fluidically connected in sequence and form a second circuit for circulating circulating water. The circulation pump is arranged on the second circuit.

[0008] In the above preferred solution, it is further preferred that the circulation pump is adjacent to the upstream of the water inlet of the water heater. It is also further preferred that a check valve is arranged at the water outlet of the circulation pump.

[0009] In the above preferred embodiment, further preferably, the anaerobic sewage treatment system further comprises a water supply pipeline fluidly connected to the water inlet of the water heater, and the water supply pipeline is provided with a normally closed water supply valve.

[0010] In the above technical solution, preferably, a sewage pump is also arranged between the water collection tank and the degradation tank.

[0011] In the above technical solution, preferably, a drainage pump is also arranged between the degradation tank and the wastewater tank.

[0012] In the above technical solution, preferably, a wastewater pump is also arranged between the wastewater pool and the fourth branch.

[0013] Compared with the traditional anaerobic sewage treatment system, the technical solution provided by the utility model makes full use of the characteristic that the anaerobic degradation of sewage is an exothermic reaction (that is, industrial sewage can still maintain a high temperature after anaerobic degradation), and absorbs part of the heat of the industrial sewage after anaerobic degradation through the water source heat pump and transfers this part of the heat to the industrial sewage that is about to be anaerobicly degraded. Therefore, when the anaerobic sewage treatment system provided by the technical solution heats the industrial sewage that is about to be anaerobicly degraded, it only needs to pay less energy to the water source heat pump, which effectively reduces the energy required for the system to be invested in heating. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A system diagram of the anaerobic sewage treatment system provided by the utility model;

[0015] Figure 2 for Figure 1 The flow chart of the anaerobic sewage treatment system is shown; wherein the arrows in the figure indicate the flow direction of industrial sewage.

[0016] Note in the figure:

[0017] 100. Anaerobic sewage treatment system; 10. Water collection tank; 20. Degradation tank; 30. Wastewater tank; 40. Sewage network management;

[0018] 1. Solar water heater; 11. Circulation pump; 12. Heat exchanger; 13. Water supply valve;

[0019] 2. Water source heat pump; 21. Compressor; 22. Air cooler; 23. Expansion valve; 24. Evaporator; 25. Sewage pump; 26. Drain pump; 27. Wastewater pump. DETAILED DESCRIPTION

[0020] In order to explain in detail the technical content, structural features, objectives and effects of the present application, the technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0021] In this application, spatially relative terms such as "under", "below", "under", "lower", "above", "upper", "above", "higher", "side" (for example, as in "sidewall"), etc., are used to describe the relationship of one element to another (other) element as shown in the accompanying drawings. The spatially relative terms are intended to include different orientations of the device in use, operation and / or manufacture in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, the elements described as "under" or "beneath" other elements or features will then be positioned as "above" the other elements or features. Therefore, the exemplary term "under" can include both above and below orientations. In addition, the device can be positioned otherwise (for example, rotated 90 degrees or at other orientations), so the spatially relative descriptors used herein are interpreted accordingly.

[0022] Figure 1 The anaerobic sewage treatment system 100 provided by the utility model is shown, which can use anaerobic bacteria to decompose organic matter (carbohydrates, proteins, fats, etc.) in industrial sewage and produce methane for users to burn. Specifically, the anaerobic sewage treatment system 100 includes a water collection tank 10 for temporarily storing untreated industrial sewage, a degradation tank 20 for anaerobic degradation of industrial sewage, a wastewater tank 30 for temporarily storing treated industrial sewage, a sewage network pipe 40 for sewage discharge, a solar water heater 1 and a water source heat pump 2.

[0023] The solar water heater 1 can use sunlight to heat circulating water. Specifically, the solar water heater 1 has a water heater inlet for circulating water to flow in and a water heater outlet for circulating water to flow out. The anaerobic sewage treatment system 100 also includes a circulating pump 11 and a heat exchanger 12 disposed in the water collection tank 10. The water heater outlet, the heat exchanger 12 and the water heater inlet are fluidly connected in sequence to form a loop for circulating water to circulate. The circulating pump 11 is arranged on the loop to provide flow power to the circulating water.

[0024] The water collection tank 10 is located at the uppermost part of the anaerobic sewage treatment system 100, and can receive industrial sewage discharged from the factory. The water collection tank 10 includes a sewage side water inlet for the industrial sewage to flow in and a sewage side water outlet for the industrial sewage to flow out. The industrial sewage is preliminarily preheated by the circulating water in the water collection tank 10, that is, the circulating water obtains part of the heat of the received solar rays in the solar water heater 1 and transfers the above heat to the industrial sewage through the heat exchanger 12.

[0025] Furthermore, the circulation pump 11 is arranged upstream of the water inlet of the solar water heater 1, where the circulating water temperature is relatively low, which can effectively reduce the possibility of cavitation of the circulation pump 11. Considering that the solar water heater 1 is installed at a relatively high height, a check valve (not shown in the figure) is also arranged at the outlet of the circulation pump 11 to prevent the circulating water from flowing back when the circulation pump 11 stops running.

[0026] Furthermore, the anaerobic wastewater treatment system 100 is also equipped with a water supply pipeline (not shown in the figure) connected to the water inlet of the solar water heater 1, and a normally closed water supply valve 13 is arranged on the water supply pipeline to be opened when water supply is needed.

[0027] The water source heat pump 2 includes a compressor 21, an air cooler 22, an expansion valve 23 and an evaporator 24. The air cooler 22 has a first branch and a second branch that can exchange heat with each other, and the evaporator 24 has a third branch and a fourth branch that can exchange heat with each other. The compressor 21, the first branch of the air cooler 22, the expansion valve 23 and the third branch of the evaporator 24 are fluidly connected in sequence to form a loop for refrigerant circulation.

[0028] Among them, the compressor 21 provides flow power for the refrigerant in the above-mentioned circuit, and compresses the high-temperature and low-pressure refrigerant fluid into a high-temperature and high-pressure refrigerant fluid; the air cooler 22 allows the refrigerant to release heat to the outside, and the high-temperature and high-pressure refrigerant fluid is converted into a low-temperature and high-pressure refrigerant fluid here; the expansion valve 23 can utilize the throttling effect to convert the low-temperature and high-pressure refrigerant fluid into a low-temperature and low-pressure refrigerant fluid; finally, the evaporator 24 allows the refrigerant to absorb external heat here, and the low-temperature and low-pressure refrigerant fluid is converted into a high-temperature and low-pressure refrigerant fluid here.

[0029] The sewage side outlet of the water collection tank 10, the second branch of the air cooler 22 and the degradation tank 20 are fluidically connected in sequence. The anaerobic sewage treatment system 100 is also equipped with a sewage pump 25 located on the fluid path between the water collection tank 10 and the air cooler 22 to provide flow power to the sewage.

[0030] The sewage flowing out of the water collection tank 10 absorbs part of the heat of the refrigerant at the air cooler 22 of the heat pump 2, and then flows into the degradation tank 20 for anaerobic degradation reaction. The anaerobic degradation reaction generally includes a hydrolysis stage, an acid production stage, and a methane production stage. In the hydrolysis stage, the carbohydrates, proteins, and fats in the sewage are hydrolyzed into monosaccharides, amino acids, and fatty acids by the corresponding biological enzymes; in the acid production stage, the monosaccharides, amino acids, and fatty acids in the sewage are decomposed into acetic acid, propionic acid, and phenols by the corresponding acid production, accompanied by the production of hydrogen, carbon dioxide, and oxygen; finally, in the methane production stage, methane bacteria convert acetic acid, acetate, carbon dioxide, and hydrogen into methane.

[0031] The degradation tank 20, the wastewater tank 30 and the fourth branch of the evaporator 24 are fluidly connected in sequence, and the anaerobic sewage treatment system 100 is also equipped with a drainage pump 26 located between the degradation tank 20 and the wastewater tank 30 and a wastewater pump 27 located between the wastewater tank 25 and the fourth branch to provide flow power for the industrial sewage. Finally, the industrial sewage that loses part of its heat in the fourth branch flows into the sewage network pipe 40 for sewage discharge.

[0032] It should be noted that the anaerobic degradation process of industrial wastewater is an exothermic reaction, that is, the industrial wastewater after the reaction still maintains a relatively high temperature. Generally speaking, the industrial wastewater discharged from the factory is about 25°C, and the industrial wastewater in the degradation tank 20 needs to be maintained at the optimal reaction temperature of 35°C, while the industrial wastewater in the wastewater tank 30 can be maintained at 30°C. It can be understood that for a water source heat pump, the industrial wastewater in the wastewater tank 30 is a relatively ideal heat source.

[0033] The anaerobic sewage treatment system 100 proposed in the utility model utilizes the above-mentioned characteristics to preheat the untreated industrial sewage through the solar water heater 1, and then utilizes the water source heat pump 2 to absorb part of the heat of the industrial sewage after anaerobic degradation and transfer the heat to the industrial sewage to be anaerobicly degraded. Therefore, when heating the industrial sewage to be anaerobically degraded, the anaerobic sewage treatment system 100 only needs to pay less energy to the water source heat pump, which effectively reduces the energy required for the system to be invested when heating. In addition, since the outlet water temperature of the air cooler 22 side of the water source heat pump 2 is relatively low and the inlet water temperature of the evaporator 24 is relatively high, the water source heat pump 2 is always in a high-efficiency operation state, and the overall system COP (Coefficient Of Performance, i.e., refrigeration performance coefficient) is above 6.

[0034] The above embodiments are only for illustrating the technical concept and features of the present application, and their purpose is to enable people familiar with the technology to understand the content of the present application and implement it accordingly, and they cannot be used to limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit of the present application should be included in the protection scope of the present application.

Claims

1. An anaerobic sewage treatment system, characterized in that: It includes a water collection tank capable of receiving industrial sewage, a degradation tank capable of anaerobic degradation of industrial sewage, a wastewater tank capable of receiving industrial sewage after anaerobic degradation, a water source heat pump and a sewage network pipe for sewage discharge. The water source heat pump includes a compressor, an air cooler, an expansion valve and an evaporator. The air cooler has a first branch and a second branch capable of heat exchange. The evaporator has a third branch and a fourth branch capable of heat exchange. The compressor, the first branch, the expansion valve and the third branch are sequentially fluidly connected and form a first loop for circulating refrigerant. The water collection tank, the second branch and the degradation tank are sequentially fluidly connected to heat the industrial sewage entering the degradation tank. The degradation tank, the wastewater tank, the fourth branch and the sewage network pipe are fluidically connected in sequence to recover the heat of the industrial sewage in the wastewater tank.

2. The anaerobic sewage treatment system according to claim 1, characterized in that: It also includes a solar water heater, a heat exchanger and a circulation pump. The heat exchanger is arranged in the water collection tank. The solar water heater includes a water outlet and a water inlet. The water outlet, the heat exchanger and the water inlet of the water heater are fluidically connected in sequence and form a second circuit for circulating water. The circulation pump is arranged on the second circuit.

3. The anaerobic sewage treatment system according to claim 2, characterized in that: The circulation pump is adjacent to the upstream of the water inlet of the water heater.

4. The anaerobic sewage treatment system according to claim 3, characterized in that: A check valve is arranged at the water outlet of the circulation pump.

5. The anaerobic sewage treatment system according to claim 2, characterized in that: It also includes a water supply pipeline which is fluidically connected to the water inlet of the water heater, and a normally closed water supply valve is arranged on the water supply pipeline.

6. The anaerobic sewage treatment system according to claim 1, characterized in that: A sewage pump is also arranged between the water collection tank and the degradation tank.

7. The anaerobic sewage treatment system according to claim 1, characterized in that: A drainage pump is also arranged between the degradation pool and the wastewater pool.

8. The anaerobic sewage treatment system according to claim 1, characterized in that: A wastewater pump is also arranged between the wastewater pool and the fourth branch.

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