Biogas slurry medicament-free dehydration equipment

Abstract

The utility model discloses biogas slurry medicament-free dehydration equipment which comprises a biogas slurry tank, a rotary drum grating, a hydraulic screen, a ceramic membrane device, a biogas slurry concentration tank and a centrifugal dehydrator, the biogas slurry tank is connected into the rotary drum grating through a pipeline, the lower part of the rotary drum grating is connected with the hydraulic screen, the hydraulic screen is connected with the ceramic membrane device through a pipeline, and the ceramic membrane device is connected with the centrifugal dehydrator. The ceramic membrane device is provided with a clear water outlet and a concentrated water outlet, the clear water outlet is used for being connected with a sewage treatment system, the concentrated water outlet is connected into a biogas slurry concentration tank, and the biogas slurry concentration tank is connected with a centrifugal dehydrator through a pipeline. Through the mode, the biogas slurry medicament-free dehydration equipment provided by the utility model has the advantages that an internal circulation line is constructed by the pretreatment unit, the concentration unit and the solid slag separation unit, so that the biogas slurry is dehydrated in the circulation process, PAC and PAM medicaments do not need to be added, the operation cost can be obviously reduced, the equipment structure is compact, the occupied area is small, the dehydrated effluent is clear, and the system solid slag recovery rate is high; and the operation stability of a rear-end sewage treatment system is obviously improved.

Description

Technical Field

[0001] The utility model relates to the field of urban organic solid waste treatment equipment, in particular to a chemical agent-free dehydration device for biogas slurry. Background Art

[0002] During the anaerobic digestion of wet garbage, a large amount of biogas slurry is generated. Biogas slurry is a wastewater with high water content, a solid-liquid mixture, and also mixed with sediment coagulated during the growth of microorganisms. The dehydration of biogas slurry is one of the main systems in the wet garbage treatment project. Similar to the dewatering of biochemical sludge in the sewage treatment system, the dehydration of biogas slurry usually includes two parts: conditioning before dehydration and dehydration. Conditioning before dehydration is to improve the dehydration performance of biogas slurry by adding conditioning agents. PAC, PAM, etc. are commonly used biogas slurry conditioning agents. The conditioning process of biogas slurry consumes a large amount of conditioning agents, and with the addition of conditioning agents, the total amount of dehydrated biogas slurry also increases. Therefore, at present, the main problems faced by biogas slurry dehydration are large consumption of chemical agents, high dehydration cost, and unclear effluent.

[0003] CN 208413980 proposes a complete set of devices for dehydrating biogas slurry from biomass anaerobic fermentation, including a dehydration equipment group and a conveyor. The dehydration equipment group includes at least two mirror-image dehydration separators, and the conveyor is located between the two mirror-image dehydration separators. The processing capacity is improved through the combination of two or more mirror-image dehydration separators. Although this complete set of devices can achieve chemical agent-free dehydration, the effluent obtained by dehydration is not clear and the moisture content of the solid residue is high.

[0004] CN 117985802 proposes a solid-liquid separation device for anaerobic fermentation residues based on the dissolved air flotation technology, including a screw extrusion device and a flotation device. The high-solid-content biogas residue is extruded by the screw extrusion device, and the flotation device removes fine sludge flocculent particles to achieve the solid-liquid classification of biogas slurry. However, the flotation device still needs to add flocculation agents and the moisture content of the flotation slag is high. Summary of the Utility Model

[0005] The main technical problem to be solved by the utility model is to provide a chemical agent-free dehydration device for biogas slurry. By constructing an internal circulation line through a pretreatment unit, a concentration unit, and a solid residue separation unit, the biogas slurry is dehydrated during the circulation process, without the need to add PAC and PAM agents, which can significantly reduce the operating cost, the equipment structure is compact and occupies a small area, the dehydration effluent is clear, the system solid residue recovery rate is high, and the operating stability of the subsequent sewage treatment system is significantly improved.

[0006] To solve the above technical problems, a technical solution adopted by the present utility model is: to provide a pharmaceutical-free dehydration device for biogas slurry, including a biogas slurry tank, a drum grille, a hydraulic screen, a ceramic membrane device, a biogas slurry concentration tank, and a centrifugal dehydrator. The biogas slurry tank is connected to the drum grille through a pipeline. The drum grille is connected to the hydraulic screen below. The hydraulic screen is connected to the ceramic membrane device through a pipeline. The ceramic membrane device is provided with a clean water outlet and a concentrated water outlet. The clean water outlet is used to connect to the sewage treatment system. The concentrated water outlet is connected to the biogas slurry concentration tank. The biogas slurry concentration tank is connected to the centrifugal dehydrator through a pipeline. The centrifugal dehydrator has a solid residue outlet and a clear liquid outlet. The solid residue outlet is used to discharge the solid residue and transport it out. The clear liquid outlet is connected back to the biogas slurry tank through a pipeline.

[0007] In a preferred embodiment of the present utility model, the ceramic membrane device is a tank body with a ceramic membrane filter element built therein. The ceramic membrane device is designed with an upstream side port, a downstream side port, and a clean water port. The upstream side port is provided with a raw water pipeline. The downstream side port is provided with a downstream three-way joint. The downstream three-way joint is respectively connected with a concentrated water pipeline and a reflux pipeline. The raw water pipeline is provided with an upstream three-way joint. The reflux pipeline is connected back to the raw water pipeline through the upstream three-way joint. The clean water port is provided with a clean water pipeline. The clean water outlet is located at the end of the clean water pipeline.

[0008] In a preferred embodiment of the present utility model, the raw water pipeline is provided with a raw water inlet on the upstream side of the upstream three-way joint. The raw water pipeline is sequentially provided with a circulation pump, a circulation pump outlet flowmeter, and a ceramic membrane front pressure gauge starting from the upstream three-way joint.

[0009] In a preferred embodiment of the present utility model, a concentrated water outlet pressure gauge is further provided between the downstream side port and the downstream three-way joint. The concentrated water pipeline is provided with a concentrated water discharge regulating valve. The concentrated water outlet is located at the end of the concentrated water pipeline.

[0010] In a preferred embodiment of the present utility model, the clean water pipeline is sequentially provided with a clear liquid outlet pressure gauge, a clean water discharge regulating valve, and a clean water discharge float flowmeter starting from the clean water port.

[0011] In a preferred embodiment of the present utility model, a biogas slurry intermediate tank is further provided between the hydraulic screen and the ceramic membrane device. An ultrafiltration feed pump is further provided between the biogas slurry intermediate tank and the ceramic membrane device. A centrifugal feed pump is further provided between the biogas slurry concentration tank and the centrifugal dehydrator. A biogas slurry lift pump is further provided between the biogas slurry tank and the drum grille.

[0012] The beneficial effects of the present utility model are as follows: A medicament-free dehydration device for biogas slurry provided by the present utility model constructs an internal circulation line through a pretreatment unit, a concentration unit, and a solid residue separation unit, enabling the dehydration of biogas slurry during the circulation process without the need to add PAC and PAM medicaments, which can significantly reduce the operation cost. The device has a compact structure and occupies a small area, the dehydrated effluent is clear, the solid residue recovery rate of the system is high, and the operation stability of the subsequent sewage treatment system is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for use in the description of the embodiments. Obviously, the following-described drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings, where:

[0014] Figure 1 is the overall structure diagram of a medicament-free dehydration device for biogas slurry of the present utility model;

[0015] Figure 2 is the structure diagram of the ceramic membrane device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model. Obviously, the described embodiments are only some of the embodiments of the present utility model, rather than all of them. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present utility model.

[0017] As Figure 1-2 shown, the embodiments of the present utility model include:

[0018] A medicament-free dehydration device for biogas slurry includes a biogas slurry tank 1, a drum screen 2, a hydraulic screen 3, a ceramic membrane device 4, a biogas slurry concentration tank 5, and a centrifuge 6. The biogas slurry tank 1 is connected to the drum screen 2 through a pipeline. The drum screen 2 is connected to the hydraulic screen 3 below. The hydraulic screen 3 is connected to the ceramic membrane device 4 through a pipeline. The ceramic membrane device 4 is provided with a clear water outlet 401 and a concentrated water outlet 402. The clear water outlet 401 is used to connect to a sewage treatment system 403. The concentrated water outlet 402 is connected to the biogas slurry concentration tank 5. The biogas slurry concentration tank 5 is connected to the centrifuge 6 through a pipeline. The centrifuge 6 has a solid residue outlet 601 and a clear liquid outlet 602. The solid residue outlet 601 is used to discharge solid residues and transport them out 603. The clear liquid outlet 602 is connected back to the biogas slurry tank 1 through a pipeline.

[0019] Among them, the rotary drum grille 2 and the hydraulic screen 3 constitute the pretreatment unit 100 in the whole set of equipment, the ceramic membrane device 4 constitutes the biogas slurry concentration unit 200 in the whole set of equipment, and the biogas slurry concentration tank 5 and the centrifuge 6 constitute the solid residue separation unit 300 in the whole set of equipment. Each unit constructs a circulation line, and the chemical-free dehydration treatment of biogas slurry can be realized in one circulation process. Through pretreatment, ceramic ultrafiltration membrane filtration and concentration, and solid-liquid separation by the centrifuge 6, it is possible to realize that no flocculant is added during the biogas slurry dehydration process, while ensuring the clarity of the effluent, and solving problems such as large consumption of chemicals, low recovery rate of solid residues, and turbidity of the dehydrated clear liquid in the biogas slurry dehydration process of traditional food waste treatment plants.

[0020] Specifically, the ceramic membrane device 4 is a tank body with a ceramic membrane filter element built therein. The ceramic membrane device 4 is designed with an upstream side port 91, a downstream side port 92 and a clean water port 93. The upstream side port 91 is provided with a raw water pipeline 911, the downstream side port 92 is provided with a downstream three-way joint 912, the downstream three-way joint 912 is respectively connected with a concentrated water pipeline 913 and a reflux pipeline 914. An upstream three-way joint 915 is provided on the raw water pipeline 911, and the reflux pipeline 914 is reflux-connected to the raw water pipeline 911 through the upstream three-way joint 915. The clean water port 93 is provided with a clean water pipeline 916, and the clean water outlet 401 is located at the end of the clean water pipeline 916.

[0021] Further, the raw water pipeline 911 is provided with a raw water inlet 917 on the upstream side of the upstream three-way joint 915. The raw water pipeline 911 is sequentially provided with a circulation pump 921, a circulation pump outlet flowmeter 922 and a ceramic membrane front pressure gauge 923 starting from the upstream three-way joint 915.

[0022] Further, a concentrated water outlet pressure gauge 931 is also provided between the downstream side port 92 and the downstream three-way joint 912. A concentrated water discharge regulating valve 932 is provided on the concentrated water pipeline 913, and the concentrated water outlet 402 is located at the end of the concentrated water pipeline 913.

[0023] Further, the clean water pipeline 916 is sequentially provided with a clear liquid outlet pressure gauge 941, a clean water discharge regulating valve 942 and a clean water discharge rotameter 943 starting from the clean water port 93.

[0024] Further, a biogas slurry intermediate tank 601 is also provided between the hydraulic screen 3 and the ceramic membrane device 4. An ultrafiltration feed pump 602 is also provided between the biogas slurry intermediate tank 601 and the ceramic membrane device 4. A centrifuge feed pump 603 is also provided between the biogas slurry concentration tank 5 and the centrifuge 6. A biogas slurry lift pump 604 is also provided between the biogas slurry tank 1 and the rotary drum grille 2.

[0025] The pretreatment unit 100 is used to separate impurities with larger particle sizes, and the separated impurities enter the biogas slurry concentration tank 5. The bar gap of the drum screen 2 is 2.0 mm, and the filtration accuracy of the hydraulic screen 3 is 200 μm.

[0026] The concentration unit 200 is a high-flux ceramic membrane device 425, with the area of a single membrane tube being 0.24 m 2 , the membrane pore size is 200 nm, the designed operating pressure is 0 - 1.0 MPa, and it can tolerate a pH range of 1 - 14. When the concentration unit 200 starts to operate, it is controlled by the pressure difference before and after the ceramic membrane device 4 to achieve the filtration and concentration of biogas slurry. When the concentration unit 200 starts to operate, the pretreated biogas slurry enters from the raw water inlet 917, and after being pressurized by the circulation pump 921, the flowmeter 922 at the outlet of the circulation pump is ensured to be stable, so that the pressure of the pressure gauge 923 at the front end of the ceramic membrane is 0.5 - 0.8 Mpa.

[0027] During system operation, the pressure of the pressure gauge 931 at the concentrated water outlet is 0.1 - 0.3 Mpa. By adjusting the opening and closing size of the concentrated water discharge regulating valve 932, part of the concentrated liquid is returned to the front end of the circulation pump 921 through the reflux pipeline 914, and at the same time, the water production ratio of the concentration unit 200 is adjusted. After being treated by the ceramic membrane device 4, the clear liquid is clear and bright, and the suspended particulate matter is less than 500 mg / L.

[0028] The centrifuge 6 mainly processes the concentrated biogas slurry in the biogas slurry concentration tank 5. The solid content of the influent of the biogas slurry concentration tank 5 is 7% - 11%. After being treated by the centrifuge 6, solid residues with a solid content of 25% - 32% and centrifuge clear liquid with a solid content of 2% - 4% are obtained.

[0029] The centrifuge clear liquid of the conventional centrifuge 6 is collected through a pipeline and then returned to the biogas slurry tank 1. In this way, the biogas slurry can be cycled out without adding chemicals.

[0030] The processing material used in this embodiment is the material of anaerobic residual biogas slurry from food waste. The processing capacity of this equipment can reach 40.0 m 3 / h, and the solid content of the raw biogas slurry is 3%. After being treated by the chemical-free dewatering system, 4.5 m 3 / h of separated solid residues with an average solid content of 27% and 35.5 m 3 / h of clear liquid with suspended substances less than 500 mg / L enter the subsequent sewage treatment system 403.

[0031] In summary, the present utility model provides a biogas slurry dehydration device without chemicals. By constructing an internal circulation line through the pretreatment unit 100, the concentration unit 200, and the solid residue separation unit 300, the biogas slurry is dehydrated during the circulation process without the need to add PAC and PAM chemicals, which can significantly reduce the operating cost. The device has a compact structure, occupies a small area, the dehydrated effluent is clear, the system has a high solid residue recovery rate, and significantly improves the operating stability of the subsequent sewage treatment system 403.

[0032] The above are only the embodiments of the present utility model, and do not limit the patent scope of the present utility model accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification of the present utility model, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present utility model.

Claims

1. A biogas slurry dehydration device without chemicals, characterized in that: It includes a biogas slurry tank, a rotary drum screen, a hydraulic screen, a ceramic membrane device, a biogas slurry concentration tank and a centrifugal dehydrator. The biogas slurry tank is connected to the rotary drum screen through a pipeline, the rotary drum screen is connected to the hydraulic screen below, the hydraulic screen is connected to the ceramic membrane device through a pipeline, the ceramic membrane device is provided with a clean water outlet and a concentrated water outlet, the clean water outlet is used to connect to a sewage treatment system, the concentrated water outlet is connected to the biogas slurry concentration tank, the biogas slurry concentration tank is connected to the centrifugal dehydrator through a pipeline, the centrifugal dehydrator has a solid residue outlet and a clear liquid outlet, the solid residue outlet is used to discharge the solid residue and transport it outside, and the clear liquid outlet is refluxed through a pipeline and connected to the biogas slurry tank.

2. The biogas slurry non-chemical dehydration equipment according to claim 1, characterized in that: The ceramic membrane device is a tank body with a built-in ceramic membrane filter element. The ceramic membrane device is designed with an upstream port, a downstream port and a clean water port. The upstream port is provided with a raw water pipeline, and the downstream port is provided with a downstream tee. The downstream tee is respectively connected to a concentrated water pipeline and a return pipeline. The raw water pipeline is provided with an upstream tee, and the return pipeline is connected to the raw water pipeline through the upstream tee. The clean water port is provided with a clean water pipeline, and the clean water outlet is located at the end of the clean water pipeline.

3. The biogas slurry non-chemical dehydration equipment according to claim 2 is characterized in that: The raw water pipeline is provided with a raw water inlet on the upstream side of the upstream tee, and the raw water pipeline is provided with a circulation pump, a circulation pump outlet flow meter, and a ceramic membrane front end pressure gauge in sequence from the upstream tee.

4. The biogas slurry non-chemical dehydration equipment according to claim 2, characterized in that: A concentrated water outlet pressure gauge is also provided between the downstream port and the downstream tee, a concentrated water discharge regulating valve is provided on the concentrated water pipeline, and the concentrated water outlet is located at the end of the concentrated water pipeline.

5. The biogas slurry non-chemical dehydration equipment according to claim 2, characterized in that: The clean water pipeline is provided with a clean liquid outlet pressure gauge, a clean water discharge regulating valve, and a clean water discharge float flowmeter in sequence from the clean water port.

6. The biogas slurry non-chemical dehydration equipment according to claim 1, characterized in that: A biogas slurry intermediate tank is provided between the hydraulic screen and the ceramic membrane device, an ultrafiltration water inlet pump is provided between the biogas slurry intermediate tank and the ceramic membrane device, a centrifugal feed pump is provided between the biogas slurry concentration tank and the centrifugal dehydrator, and a biogas slurry lifting pump is provided between the biogas slurry tank and the drum screen.

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