A new biogas slurry membrane filtration device based on silicon carbide membrane

Abstract

The application discloses a novel biogas slurry membrane filtration device based on silicon carbide membranes, comprising: a silicon carbide membrane assembly, which is composed of four groups of membrane groups in parallel connection, and two ends of each group of membrane groups are connected with a shunt pipe and a collection pipe; each group of membrane groups comprises four silicon carbide tubular membrane tubes, and the four silicon carbide tubular membrane tubes are connected in series, each silicon carbide tubular membrane tube is provided with a plurality of large through-hole structures along the axial direction thereof, the diameter of the large through-hole structure is 8 mm, and the pore size of the membrane tube is 150 nm; and a cleaning assembly connected with the silicon carbide membrane assembly and used for cleaning the silicon carbide membrane assembly according to a preset mode. The application has stronger anti-clogging performance, is suitable for anaerobic biogas slurry treatment with high solid content and more organic fiber components, effectively alleviates the problems of scaling and fiber winding and clogging, and solves the problem of membrane strength through the thickening design of the membrane tube spacing.

Description

Technical Field

[0001] This application relates to a novel biogas slurry membrane filtration device based on silicon carbide membrane, belonging to the field of high-concentration organic wastewater treatment technology. Background Technology

[0002] In China, the traditional pretreatment process for anaerobic fermentation of high-concentration organic wastewater into biogas slurry, consisting of centrifugal pretreatment followed by two-stage air flotation, is commonly used. This pretreatment results in high suspended solids (SS) in the effluent, leading to high energy consumption in subsequent wastewater treatment systems, difficulties in resource recovery, and the need to treat large quantities of membrane concentrate. This has become a significant bottleneck restricting the high-quality development of wastewater treatment technology for high-concentration organic wastewater. Currently, membrane filtration technology is an emerging wastewater treatment technology for biogas slurry pretreatment. Existing anaerobic biogas slurry membrane treatment systems generally use polyvinylidene fluoride (PVDF) membrane materials. However, in actual operation, these membranes suffer from poor oil resistance, poor high-temperature resistance, easy aging, severe membrane fouling, frequent cleaning, and high system energy consumption. Furthermore, traditional membrane modules are mainly arranged in series with multiple membranes, which easily leads to uneven flow rates, large membrane pressure fluctuations, and highly volatile filtration efficiency. In addition, the membrane pore size is mostly concentrated in the 20-50 nm range, resulting in low unit membrane flux, large membrane area, and high investment costs when there is no significant advantage in effluent quality. The membrane tubes are the first in China and abroad to adopt a large through-hole structure with an 8mm process. Compared with the 4mm or even smaller membrane tube diameters commonly found on the market, they have stronger anti-clogging performance and are suitable for anaerobic digester treatment with high solid content and a large amount of organic fiber. They effectively alleviate scaling and fiber entanglement clogging problems. At the same time, the thickened design of the membrane tube spacing solves the membrane strength problem. Summary of the Invention

[0003] The purpose of this application is to provide a novel biogas slurry membrane filtration device based on silicon carbide membrane, which solves the technical difficulties such as clogging and corrosion in the treatment of biogas slurry from kitchen waste in the prior art, and further promotes the transformation of kitchen waste into clean energy, achieving a win-win situation for both environmental and economic benefits.

[0004] To achieve the above objectives, this application provides the following technical solution:

[0005] A novel biogas slurry membrane filtration device based on a silicon carbide membrane includes:

[0006] A silicon carbide membrane module, wherein the silicon carbide membrane module is composed of four sets of membranes connected in parallel, and the two ends of the four sets of membranes are respectively connected to a shunt pipe and a collecting pipe;

[0007] Each membrane assembly comprises four silicon carbide tubular membrane tubes connected in series. Each silicon carbide tubular membrane tube has multiple large through-hole structures along its axial direction. The diameter of the large through-hole structures is 8 mm, and the pore size of the membrane tube is 150 nm.

[0008] A cleaning component is connected to the silicon carbide film assembly and cleans the silicon carbide film assembly according to preset settings.

[0009] Preferably, the silicon carbide tubular membrane tube comprises:

[0010] Membrane shell,

[0011] Five first silicon carbide membrane filter elements are provided, and the five first silicon carbide membrane filter elements are filled in the center of the membrane shell, and a first water production gap is formed between the five first silicon carbide membrane filter elements.

[0012] The second silicon carbide membrane filter element is provided in four pairs, which are symmetrically arranged on both sides of the first silicon carbide membrane filter element. A second water production gap is formed between the second silicon carbide membrane filter element and the first silicon carbide membrane filter element. Both the second silicon carbide membrane filter element and the first silicon carbide membrane filter element are filled in the membrane shell.

[0013] Preferably, the first silicon carbide membrane filter element is axially provided with multiple large through-hole structures and multiple first through-hole structures, and the second silicon carbide membrane filter element is axially provided with multiple large through-hole structures, multiple first through-hole structures, and multiple second through-hole structures, thereby further increasing the filtration area without affecting the strength of the first silicon carbide membrane filter element and the second silicon carbide filter element.

[0014] Preferably, the membrane housing is connected to a water production branch pipe, which is connected to the main water production pipe. The water produced by the first silicon carbide membrane filter and the second silicon carbide membrane filter converges from the first water production gap and the second water production gap to the membrane housing, then converges through the water production branch pipe to the main water production pipe, and is then discharged from the water production port.

[0015] Preferably, a circulation pipe is connected between the diversion pipe and the collection pipe, and a circulation pump is installed on the circulation pipe. The circulation pump allows the biogas slurry to pass through the membrane filtration system multiple times to achieve multiple filtrations, thereby improving filtration efficiency. At the same time, it also has the function of maintaining system pressure and stabilizing system flow.

[0016] Preferably, the cleaning assembly includes a clean water rinsing mechanism and a clean water backwashing mechanism.

[0017] Preferably, the water rinsing mechanism includes:

[0018] A clean water tank is used to store clean water.

[0019] A clean water pump, connected to the clean water tank;

[0020] The electric main valve for the cleaning pipeline is connected to the clean water pump.

[0021] The diversion pipe is provided with a clean water inlet and a clean water return outlet. The clean water return outlet is connected to the clean water tank, and the clean water inlet is connected to the electric main valve of the cleaning pipeline.

[0022] The circulating pump is connected to the circulating pipe, the circulating pipe is connected to the collecting pipe, and the collecting pipe is connected to the silicon carbide tubular membrane tube.

[0023] Clean water flows from the clean water tank through the cleaning pump and the electric main valve of the cleaning pipeline into the clean water inlet. It is then pressurized by the circulation pump and enters the collection pipe through the circulation pipe. It is then distributed to the silicon carbide tubular membrane tube to flush the large through-hole structure, the first through-hole structure, and the second through-hole structure. The flushed wastewater is collected in the diversion pipe and then returns to the clean water tank from the clean water return port.

[0024] Preferably, the clean water backwashing mechanism includes: a clean water tank connected to a clean water pump, a clean water pump connected to a backwashing inlet valve, a backwashing inlet valve connected to a backwashing inlet main pipe, a backwashing inlet main pipe connected to a backwashing branch pipe, and a backwashing branch pipe connected to the membrane housing;

[0025] Clean water exits from the clean water tank, passes through the clean water pump, backwash inlet valve, and backwash inlet main pipe, and is then distributed to various backwash branch pipes. The clean water enters the membrane housing and, under the continuous pressurization of the clean water pump, pressurizes the first silicon carbide membrane filter and the second silicon carbide membrane filter through the first and second product water gaps. The clean water passes through the first and second silicon carbide membrane filters and compresses the pollutants together into the large through-hole structure, the first through-hole structure, and the second through-hole structure, and then converges into the distribution pipe and is discharged from the backwash drain port provided on the distribution pipe.

[0026] Preferably, the cleaning assembly further includes a chemical cleaning mechanism, which restores the membrane's filtration performance by dissolving or stripping away contaminants.

[0027] Preferably, it also includes a skid mount for mounting the silicon carbide film assembly, the circulation pump, the branch pipe, the circulation pipe, and the collection pipe, facilitating overall handling and rapid installation.

[0028] The beneficial effects of this application are:

[0029] 1. The core of this device uses silicon carbide (SiC) ceramic membrane material to replace traditional organic membranes. It has excellent properties such as oil resistance, high temperature resistance, acid and alkali resistance, oxidant corrosion resistance and high mechanical strength. The operating cycle is significantly extended in high pollution load environments, the cleaning frequency is reduced and the system stability is enhanced. The membrane pore size range of 100~200nm is selected to balance high membrane flux and solid-liquid separation accuracy. While ensuring that the effluent water quality meets the standards, the membrane area and the initial investment of the system are reduced.

[0030] 2. This application adopts a “series + parallel” membrane arrangement structure: each set of equipment consists of four sets of membrane modules connected in parallel, and each set of membrane modules has four silicon carbide tubular membrane tubes connected in series. The overall arrangement direction is coaxial with the direction of the inlet water and the circulation pump, which increases the flow rate, reduces pressure loss, and significantly reduces the risk of membrane fouling.

[0031] 3. The first and second silicon carbide membrane filter elements of this application generally adopt an 8mm process large-pore structure, with some areas using a "raindrop-shaped" first pore structure and a 4mm second pore structure to further improve the filling rate. Compared with the traditional 4mm or even smaller membrane tube diameter, this structure has better clogging resistance, is suitable for anaerobic digester treatment with high solids content and high organic fiber content, effectively alleviates scaling and fiber entanglement problems, and significantly enhances the structural strength of the membrane module through the thickened membrane tube spacing design. Furthermore, the setting of the first and second permeate gaps further improves the membrane flux and permeate efficiency.

[0032] 4. This application adopts a skid-mount design, which reduces the footprint of the device and allows for rapid installation, deployment, and subsequent maintenance. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the three-dimensional structure of this application. Figure 1 ;

[0034] Figure 2 This is a schematic diagram of the three-dimensional structure of this application. Figure 2 ;

[0035] Figure 3 This is a schematic diagram of the main view structure of this application;

[0036] Figure 4 This is a cross-sectional structural schematic diagram of the first silicon carbide membrane filter element and the second silicon carbide membrane filter element of this application;

[0037] Figure 5 This is a schematic diagram of the overall connection structure of this application.

[0038] In the diagram: 1. Silicon carbide tubular membrane tube; 101. First silicon carbide membrane filter element; 102. Second silicon carbide membrane filter element; 103. Large through-hole structure; 104. First through-hole structure; 105. Second through-hole structure; 106. First water production gap; 107. Second water production gap; 2. Diverter pipe; 201. Biogas slurry inlet; 202. Biogas slurry inlet valve; 203. Clean water inlet; 204. Clean water return outlet; 205. Backwash drain outlet; 206. Backwash drain outlet valve; 207. Clean water return outlet valve; 3. Collection pipe; 301. 1. Concentrate inlet; 2. 302. Concentrate inlet valve; 3. Circulation pipe; 4. Circulation pump; 5. Backwash inlet valve; 6. Backwash inlet main pipe; 7. Backwash branch pipe; 8. Clean water tank; 9. Clean water pump; 10. Cleaning pipeline electric main valve; 11. Chemical cleaning tank; 12. Chemical cleaning pump; 13. Biogas slurry feed pump; 14. Self-cleaning filter; 15. Security filter; 16. Feed and outlet manual main valve; 18. Support frame; 19. Circulation pump mounting base; 20. Product water inlet; 21. Product water branch pipe; 22. Product water main pipe; 23. Air vent valve. Detailed Implementation

[0039] To facilitate a clear understanding of the technical means, creative features, objectives, and effects of this application, the following description, in conjunction with specific illustrations, further elaborates on this application.

[0040] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0041] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] The following disclosure provides numerous different embodiments or examples for implementing various structures of the embodiments of this application. To simplify the disclosure of the embodiments of this application, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or reference letters may be repeated in different examples of the embodiments of this application; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in the embodiments of this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0043] like Figures 1-5 As shown, a novel biogas slurry membrane filtration device based on a silicon carbide membrane is described in detail below:

[0044] The silicon carbide membrane module consists of four membrane modules connected in parallel. Each of the four membrane modules is connected to a shunt pipe 2 and a manifold pipe 3 at both ends. A membrane module branch inlet valve is installed on the connecting pipe between each of the four membrane modules and the shunt pipe 2, and a membrane module branch outlet valve is installed on the connecting pipe between each of the four membrane modules and the manifold pipe 3. Each membrane module contains four silicon carbide tubular membrane tubes 1, which are connected in series via a clamp sealing structure. Each silicon carbide tubular membrane tube 1 extends along its... Multiple large through-hole structures 103 are arranged axially, with an inner diameter of 8 mm, to facilitate the rapid passage of concentrated water. This also adapts to the treatment of anaerobic digester slurry with high solid content and high organic fiber content, effectively alleviating scaling and fiber entanglement problems. The filtration pore size of the silicon carbide tubular membrane tube 1 is selected within the range of 100~200 nm, balancing high membrane flux and solid-liquid separation accuracy. This ensures that the effluent water quality meets the standards while reducing the membrane area and initial system investment. The silicon carbide tubular membrane tube 1 includes: a membrane shell, which is a tubular structure; five first silicon carbide membrane filters 101, which are arranged in a manner that fills the center of the membrane shell, and a first water production gap 106 is formed between each of the five first silicon carbide membrane filters 101; and four second silicon carbide membrane filters 102, which are arranged symmetrically in pairs on both sides of the first silicon carbide membrane filters 101, and a second water production gap 107 is formed between the second silicon carbide membrane filters 102 and the first silicon carbide membrane filters 101, and both the second silicon carbide membrane filters 102 and the first silicon carbide membrane filters 101 are filled inside the membrane shell. Furthermore, the first silicon carbide membrane filter element 101 is axially provided with multiple large through-hole structures 103 and multiple first through-hole structures 104, and the second silicon carbide membrane filter element 102 is axially provided with multiple large through-hole structures 103, multiple first through-hole structures 104, and multiple second through-hole structures 105. The first through-hole structures 104 adopt a "raindrop-shaped" cross-section and have various sizes of "raindrop shapes." The second through-hole structures 105 have an inner diameter of 4mm. This further increases the filtration area without affecting the strength of the first silicon carbide membrane filter element 101 and the second silicon carbide filter element. Both the first silicon carbide membrane filter element 101 and the second silicon carbide filter element are made of silicon carbide (SiC) ceramic membrane material, which has excellent oil resistance, high temperature resistance, acid and alkali resistance, oxidant corrosion resistance, and high mechanical strength. In high-pollution environments, the operating cycle is significantly extended, the cleaning frequency is reduced, and the system stability is enhanced.When the target biogas slurry passes through the first silicon carbide membrane filter element 101 and the second silicon carbide membrane filter element 102, the concentrated water flows from the large through-hole structure 103, the first through-hole structure 104, and the second through-hole structure 105 to the collection pipe 3, and then returns to the biogas slurry temporary storage tank in the pretreatment stage from the concentrated water outlet 301 set on the collection pipe 3. A concentrated water outlet valve 302 is installed at the concentrated water outlet 301. The filtered water flows from the first water production gap 106 and the second water production gap 107 to the membrane shell. A water production branch pipe is connected to the membrane shell, and the water production branch pipe is connected to the water production main pipe. The water produced by the first silicon carbide membrane filter element 101 and the second silicon carbide membrane filter element 102 flows from the first water production gap 106 and the second water production gap 107 to the membrane shell, and then flows through the water production branch pipe to the water production main pipe, and then is discharged from the water production outlet. It should be noted that a water production butterfly valve is installed at the water production outlet.

[0045] As a further preferred embodiment, a circulation pipe 4 connects the diversion pipe 2 and the collection pipe 3. An exhaust valve 23 is installed on the circulation pipe 4, and a circulation pump 5 (a variable frequency pump, with adjustable flow rate and an inlet flow rate ≥4m / s, ensuring cross-flow filtration and minimizing membrane fouling; the variable frequency pump speed is also adjustable, maximizing energy savings) is installed on the circulation pipe 4. This setup offers several advantages, detailed below: I. Improved Water Quality and Treatment Efficiency: 1. Uniform Water Quality: The composition of kitchen waste biogas slurry is complex and unstable. Water quality parameters (such as COD, BOD, ammonia nitrogen, suspended solids concentration, etc.) of biogas slurry from different time periods and sources may vary significantly in the main sewage pipe. Connecting the diversion pipe 2 and the collection pipe 3 via the circulation pump 5 allows the biogas slurry to circulate within the system, ensuring thorough mixing of different water qualities and thus achieving uniform overall water quality. This prevents excessive local water quality fluctuations from impacting subsequent treatment processes. 2. Improved Biodegradability: Circulation increases the contact opportunities between microorganisms and pollutants in the biogas slurry, promoting the decomposition and transformation of organic matter by microorganisms. Some recalcitrant organic matter will be gradually degraded into smaller molecules by microorganisms during circulation, improving the biodegradability of the biogas slurry and creating more favorable conditions for subsequent biological treatment processes. II. Stable System Operation: 1. Buffering Water Quality and Quantity Shocks: The amount of food waste generated is uncertain, leading to significant fluctuations in biogas slurry production and water quality. When a large amount of high-concentration or low-concentration biogas slurry suddenly enters the collecting pipe 3, the circulating pump 5 can quickly mix this portion of biogas slurry with the liquid in the diversion pipe 2, acting as a buffer to prevent the treatment system from overloading or reducing treatment efficiency due to drastic changes in water quality and quantity. 2. Maintaining Stable System Pressure and Flow: The circulating pump 5 can adjust the flow rate and pressure according to the actual needs of the system, ensuring that the liquid in the collecting pipe 3 and diversion pipe 2 maintains a stable flow state. Stable pressure and flow are beneficial to the normal operation of various treatment equipment (such as pumps, valves, reactors, etc.), reducing equipment wear and failure rates, and extending equipment lifespan.

[0046] A cleaning assembly, connected to the silicon carbide membrane assembly, cleans the silicon carbide membrane assembly according to preset settings. The cleaning assembly includes a clean water rinsing mechanism and a clean water backwashing mechanism. Specifically, the clean water rinsing mechanism includes: a clean water tank 9 for storing clean water; a clean water pump 10 connected to the clean water tank 9; a cleaning pipeline electric main valve 11 connected to the clean water pump 10; a branch pipe 2 equipped with a clean water inlet 203 and a clean water return outlet 204, the clean water return outlet 204 being connected to the clean water tank 9, and the clean water inlet 203 being connected to the cleaning pipeline electric main valve 11; a circulation pump 5 connected to the circulation pipe 4, the circulation pipe 4 connected to the collecting pipe 3, and the collecting pipe 3 connected to the silicon carbide tubular membrane tube 1; and a clean water rinsing path. The process is as follows: Clean water exits from the clean water tank 9, passes through the cleaning pump and the electric main valve 11 of the cleaning pipeline, and enters the clean water inlet 203 of the diversion pipe 2. It is then pressurized by the circulation pump 5 (it should be noted that the circulation pump 5 is a commercially available variable frequency circulation pump capable of forward and reverse rotation, such as Shanghai Cangmao Industrial's SXF-25) and flows through the circulation pipe 4 into the collection pipe 3. From there, it is distributed to the silicon carbide tubular membrane tube 1, rinsing the large through-hole structure 103, the first through-hole structure 104, and the second through-hole structure 105. The rinsed water converges back into the diversion pipe 2 and then returns to the clean water tank 9 through the clean water return port 204. It should be noted that during the rinsing process, the biogas slurry inlet valve 202, the concentrated water inlet valve 302, and the backwash drain valve 206 on the biogas slurry inlet 201 are in a closed state.

[0047] The clean water backwashing mechanism includes the following: the clean water tank 9 is connected to the clean water pump 10; the clean water pump 10 is connected to the backwash inlet valve 6; the backwash inlet valve 6 is connected to the backwash inlet main pipe 7; the backwash inlet main pipe 7 is connected to the backwash branch pipe 8; a one-way valve is installed on the backwash branch pipe 8, which ensures that the filtered water during the water production process is collected in the water production main pipe and does not leak from the backwash inlet main pipe 7; the backwash branch pipe 8 is connected to the membrane housing; the clean water backwashing path is as follows: Clean water exits from the clean water tank 9, passes through the clean water pump 10 and the backwash inlet valve 6, and enters the backwash inlet main pipe 7. Afterward, it is distributed to each backwash branch pipe 8. The clean water enters the membrane housing and, under the continuous pressurization of the clean water pump 10, pressurizes the first silicon carbide membrane filter element 101 and the second silicon carbide membrane filter element 102 through the first product water gap 106 and the second product water gap 107. The clean water passes through the first silicon carbide membrane filter element 101 and the second silicon carbide membrane filter element 102, pressing the contaminants along with the water. The large through-hole structure 103, the first through-hole structure 104, and the second through-hole structure 105 converge into the diversion pipe 2 and are discharged from the backwash drain port 205 set on the diversion pipe 2. A backwash drain port valve 206 is installed at the backwash drain port 205. It should be noted that when the clean water backwashing mechanism is working, the membrane module branch outlet valve, the clean water return port valve 207, the biogas slurry inlet valve 202, and the clean water inlet valve installed on the clean water inlet 203 are all in the closed state.

[0048] In a preferred embodiment, the cleaning assembly further includes a chemical cleaning mechanism. Chemical cleaning restores the membrane's filtration performance by dissolving or stripping contaminants. The difference between the chemical cleaning mechanism and the water rinsing and backwashing mechanisms is that the chemical cleaning mechanism connects the chemical cleaning pump 13 and the chemical cleaning tank 12. The chemical cleaning tank 12 is configured with acidic, alkaline, or oxidizing solutions according to different needs. The chemical cleaning mechanism is generally cleaned once a month, while water rinsing is generally done once a day.

[0049] The skid is used to install the silicon carbide membrane module, the circulation pump 5, the branch pipe 2, the circulation pipe 4, the collection pipe 3, the product water pipe, the backwash pipe, etc., and the skid is equipped with two sets of the above-mentioned mechanisms to facilitate overall transportation and quick installation, while greatly reducing the floor space occupied. The skid consists of two support frames 18 and a circulation pump mounting base 19.

[0050] Principle: The biogas slurry, after being pretreated by the self-cleaning filter 15 and security filter 16 in the pretreatment stage via the biogas slurry feed pump 14 from the biogas slurry temporary storage tank, enters the biogas slurry inlet 201 through the manual main valve 17 of the feed and outlet pipes, and then flows into the diversion pipe 2. The diversion pipe 2 distributes the biogas slurry into four connected membrane modules. The biogas slurry then enters the four series-connected silicon carbide tubular membrane tubes 1. As the biogas slurry passes through the first silicon carbide membrane filter element 101 and the second silicon carbide membrane filter element 102, the filtered water flows out from the first water production gap 1. The water from the second water production gap 107 converges into the membrane shell, then flows from the water production branch pipe 21 to the water production main pipe 22, and is discharged from the water production outlet 20. The unfiltered concentrate flows from the large through-hole structure 103, the first through-hole structure 104, and the second through-hole structure 105 to the collection pipe 3, and then flows back from the concentrate outlet 301 to the biogas slurry storage tank in the pretreatment stage. During this process, the circulation pump 5 also starts, drawing part of the concentrate in the collection pipe 3 to the diversion pipe 2, where it mixes with the biogas slurry from the pretreatment stage before entering the four modules for filtration. It should be noted that the pipelines in the cleaning components are all in a closed state during this process.

[0051] In a preferred embodiment of this invention, an inorganic membrane module made of silicon carbide is selected as the core filtration unit for biogas slurry treatment. The silicon carbide membrane used has excellent resistance to fouling, chemical corrosion, and high mechanical strength. The membrane pore size is controlled within the range of 100~200 nm to balance membrane flux and retention efficiency.

[0052] In this embodiment, typical biogas slurry raw water was filtered through an organic membrane (traditional PVDF material) and the silicon carbide membrane, respectively. The resulting effluent water quality was compared as follows (based on average values):

[0053] Parameter Indicators Organic membrane effluent silicon carbide membrane effluent pH 8.08 8.10 SCOD (mg / L) 2573 2335 VFAs (mg / L) 299 309 TN (mg / L) 2655 2658 <![CDATA[NH3-N(mg / L)]]> 2516 2555 TP (mg / L) 19.6 20.1 SS (g / L) 0 0 <![CDATA[Hardness (mg / L, calculated as CaCO3)]]> 275 269 Color 100 100

[0054] As can be seen from the above data, although silicon carbide membranes adopt a larger pore size design, the quality of its effluent is basically consistent with that of organic membranes in terms of key indicators such as pH, SCOD, volatile fatty acids (VFAs), total nitrogen (TN), ammonia nitrogen (NH3-N), total phosphorus (TP), suspended solids (SS), hardness, and color, with no significant differences, and it maintains good desolvation efficiency and pollutant removal effect.

[0055] Table 2 Comparison of comprehensive performance indicators between silicon carbide film and traditional PVDF film

[0056] index Traditional PVDF membrane This utility model relates to a silicon carbide film. Service life (years) 1-2 ≥5 Membrane pore size (nm) 20~50 100~200 <![CDATA[Unit membrane flux (L / (m 2 ·h))]]> 15 ≥30 High temperature resistance (°C) ≤40 ≥100 Chemical washing cycle (d) ≤30 45 Backwash tolerance Difference excellent

[0057] Furthermore, due to its superior antifouling capabilities and high-intensity backwashing properties, silicon carbide membranes exhibit more stable flux and lower cleaning frequency during long-term operation, effectively extending membrane life and reducing operating costs. Therefore, the application of this silicon carbide membrane in biogas slurry treatment has excellent practical value and promising prospects for widespread adoption.

[0058] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of this application; all such changes and modifications fall within the scope of the claims. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A novel biogas slurry membrane filtration device based on a silicon carbide membrane, characterized in that, include: A silicon carbide membrane module, wherein the silicon carbide membrane module is composed of four sets of membranes connected in parallel, and the two ends of the four sets of membranes are respectively connected to a shunt pipe and a collecting pipe; Each membrane module comprises four silicon carbide tubular membrane tubes connected in series. Each silicon carbide tubular membrane tube has multiple large through-hole structures along its axial direction. The diameter of the large through-hole structures is 8 mm, and the filtration pore size of the silicon carbide tubular membrane tube is 150 nm. A cleaning component is connected to the silicon carbide film assembly and cleans the silicon carbide film assembly according to preset settings.

2. The novel biogas slurry membrane filtration device based on a silicon carbide membrane according to claim 1, characterized in that, The silicon carbide tubular membrane tube includes: Membrane shell, Five first silicon carbide membrane filter elements are provided, and the five first silicon carbide membrane filter elements are filled in the center of the membrane shell, and a first water production gap is formed between the five first silicon carbide membrane filter elements. The second silicon carbide membrane filter element is provided in four pairs, which are symmetrically arranged on both sides of the first silicon carbide membrane filter element. A second water production gap is formed between the second silicon carbide membrane filter element and the first silicon carbide membrane filter element. Both the second silicon carbide membrane filter element and the first silicon carbide membrane filter element are filled in the membrane shell.

3. A novel biogas slurry membrane filtration device based on a silicon carbide membrane according to claim 2, characterized in that: The first silicon carbide membrane filter element is axially provided with multiple large through-hole structures and multiple first through-hole structures, and the second silicon carbide membrane filter element is axially provided with multiple large through-hole structures, multiple first through-hole structures, and multiple second through-hole structures, thereby further increasing the filtration area without affecting the strength of the first silicon carbide membrane filter element and the second silicon carbide filter element.

4. A novel biogas slurry membrane filtration device based on a silicon carbide membrane according to claim 3, characterized in that: The membrane housing is connected to a water production branch pipe, which is connected to the main water production pipe. The water produced by the first silicon carbide membrane filter and the second silicon carbide membrane filter converges from the first water production gap and the second water production gap to the membrane housing, then converges through the water production branch pipe to the main water production pipe, and is then discharged from the water production outlet.

5. A novel biogas slurry membrane filtration device based on a silicon carbide membrane according to claim 2 or 4, characterized in that: A circulation pipe is connected between the diversion pipe and the collection pipe. A circulation pump is installed on the circulation pipe. The circulation pump allows the biogas slurry to pass through the membrane filtration system multiple times to achieve multiple filtrations, thereby improving filtration efficiency. It also helps to maintain system pressure and stabilize system flow.

6. A novel biogas slurry membrane filtration device based on a silicon carbide membrane according to claim 5, characterized in that, The cleaning components include: a clean water rinsing mechanism and a clean water backwashing mechanism.

7. A novel biogas slurry membrane filtration device based on a silicon carbide membrane according to claim 6, characterized in that: The clean water rinsing mechanism includes: A clean water tank is used to store clean water. A clean water pump is connected to the clean water tank; The electric main valve for the cleaning pipeline is connected to the clean water pump. The diversion pipe is provided with a clean water inlet and a clean water return outlet. The clean water return outlet is connected to the clean water tank, and the clean water inlet is connected to the electric main valve of the cleaning pipeline. The circulating pump is connected to the circulating pipe, the circulating pipe is connected to the collecting pipe, and the collecting pipe is connected to the silicon carbide tubular membrane tube. Clean water flows from the clean water tank through the cleaning pump and the electric main valve of the cleaning pipeline into the clean water inlet. It is then pressurized by the circulation pump and enters the collection pipe through the circulation pipe. It is then distributed to the silicon carbide tubular membrane tube to flush the large through-hole structure, the first through-hole structure, and the second through-hole structure. The flushed wastewater is collected in the diversion pipe and then returns to the clean water tank from the clean water return port.

8. A novel biogas slurry membrane filtration device based on a silicon carbide membrane according to claim 7, characterized in that: The clean water backwashing mechanism includes: a clean water tank connected to a clean water pump, a clean water pump connected to a backwashing inlet valve, a backwashing inlet valve connected to a backwashing inlet main pipe, and a backwashing inlet main pipe connected to a backwashing branch pipe, which is connected to the membrane housing. Clean water exits from the clean water tank, passes through the clean water pump, backwash inlet valve, and backwash inlet main pipe, and is then distributed to various backwash branch pipes. The clean water enters the membrane housing and, under the continuous pressurization of the clean water pump, pressurizes the first silicon carbide membrane filter and the second silicon carbide membrane filter through the first and second product water gaps. The clean water passes through the first and second silicon carbide membrane filters and compresses the pollutants together into the large through-hole structure, the first through-hole structure, and the second through-hole structure, and then converges into the distribution pipe and is discharged from the backwash drain port provided on the distribution pipe.

9. A novel biogas slurry membrane filtration device based on a silicon carbide membrane according to claim 8, characterized in that: The cleaning assembly also includes a chemical cleaning mechanism, which restores the membrane's filtration performance by dissolving or stripping away contaminants.

10. A novel biogas slurry membrane filtration device based on a silicon carbide membrane according to claim 9, characterized in that: It also includes a skid mount for mounting the silicon carbide film assembly, the circulation pump, the branch pipe, the circulation pipe, and the collection pipe, facilitating overall transport and rapid installation.

Images