A kitchen waste slurry filtration device and its filtration method

Abstract

This invention discloses a kitchen waste slurry filtration device and method. The device includes: a security filter with an inlet for receiving kitchen waste slurry and intercepting large particles in the slurry to protect downstream membrane elements; a circulation pump with its suction end connected to the outlet of the security filter; a membrane filtration assembly with its inlet connected to the outlet of the circulation pump, the membrane filtration assembly including at least one tubular ceramic membrane element, the circulation pump being configured to drive the kitchen waste slurry to flow through the membrane channels in a cross-flow manner and form turbulence within the membrane channels; a clear liquid pipeline connected to the clear liquid outlet of the membrane assembly for discharging permeate; and a concentrate pipeline connected to the concentrate outlet of the membrane assembly for discharging concentrate. By employing a tubular ceramic membrane combined with a cross-flow filtration process, and using a circulation pump to provide high flow velocity and create turbulence on the inner wall of the membrane element, the filtration flux per unit area is significantly improved, and the deposition and clogging of grease and suspended solids on the membrane surface are effectively prevented, greatly extending the cleaning cycle.

Description

Technical Field

[0001] This invention relates to the field of kitchen waste treatment technology, specifically to a kitchen waste slurry filtration device and its filtration method. Background Technology

[0002] Food waste generates a large amount of slurry during pretreatment, including slurry from hoppers and equipment draining, solid-liquid separation slurry, and slurry separated by a three-phase oil extractor. These slurries have good biodegradability and are often studied as supplementary carbon sources for downstream wastewater treatment. However, these slurries typically have drawbacks such as high solids content and high oil content, requiring effective removal of oils, suspended solids, and other impurities to meet the standards for commercial carbon sources.

[0003] In existing technologies, disc centrifuges or inorganic ceramic flat-plate membranes are commonly used to treat kitchen waste slurry. However, disc centrifuges have limited efficiency in removing grease and impurities, making it difficult to meet high carbon source requirements; while ceramic flat-plate membranes suffer from low filtration flux, large footprint, easy clogging, and inconvenient cleaning and maintenance in practical applications. Therefore, there is an urgent need to develop a filtration solution that provides high-quality filtrate, high flux, compact footprint, and is less prone to clogging. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a kitchen waste slurry filtration device and filtration method to solve the problems of low filtration efficiency, low membrane flux, and easy clogging of the membrane surface in the prior art.

[0005] This invention is achieved using the following technical solution:

[0006] A food waste slurry filtration device includes: a security filter with an inlet for receiving food waste slurry and intercepting large particles in the slurry to protect downstream membrane elements; a circulation pump with its suction end connected to the outlet of the security filter; a membrane filtration assembly with its inlet connected to the outlet of the circulation pump, the membrane filtration assembly including at least one tubular ceramic membrane element, the circulation pump being configured to drive the food waste slurry to flow through the membrane channels in a cross-flow manner and form turbulence within the membrane channels; a clear liquid pipeline connected to the clear liquid outlet of the membrane assembly for discharging permeate; and a concentrate pipeline connected to the concentrate outlet of the membrane assembly for discharging concentrate.

[0007] Preferably, the membrane filtration assembly includes a first-stage tubular ceramic membrane element and a second-stage tubular ceramic membrane element arranged in series, as well as a first liquid collection chamber located at the inlet end of the first-stage tubular ceramic membrane element and a second liquid collection chamber located at the outlet end of the second-stage tubular ceramic membrane element. The device comprises 1-6 tubular ceramic membrane elements arranged in parallel, and 1-6 tubular ceramic membrane elements arranged in parallel, wherein the kitchen waste slurry is distributed through the first collection chamber and enters the first tubular ceramic membrane element; the concentrate flowing through the first tubular ceramic membrane element enters the second tubular ceramic membrane element; and the concentrate flowing through the second tubular ceramic membrane element flows into the second collection chamber. The device further comprises a return pipeline configured to return at least a portion of the concentrate from the second collection chamber to the suction end of the circulation pump.

[0008] Preferably, the system further includes a concentration ratio adjustment system, which includes a concentrate pipeline flow meter installed on the concentrate pipeline, a clear liquid pipeline flow meter installed on the clear liquid pipeline, and adjustment control valves installed on the concentrate pipeline and the clear liquid pipeline respectively; the adjustment control valves are configured to automatically adjust their opening degree according to the measured values ​​of the concentrate pipeline flow meter and the clear liquid pipeline flow meter, so as to control the concentration ratio at a set value.

[0009] Preferably, the device further includes an automatic cleaning system configured to circulate the cleaning fluid within the device in cleaning mode; the automatic cleaning system includes a cleaning tank, a cleaning pump, a tap water pipeline, and an emptying pipeline; in cleaning mode, the emptying pipeline is connected to the bottom of the first liquid collection chamber, the second liquid collection chamber, and the security filter for emptying the liquid within the device; the inlet of the cleaning pump is connected to the outlet of the cleaning tank, and the outlet of the cleaning pump is connected to the inlet of the security filter; the cleaning tank is connected to the tap water pipeline, the clear liquid pipeline, and the concentrated liquid pipeline, respectively.

[0010] Preferably, the cleaning solution is water or an aqueous solution with added sodium hydroxide.

[0011] Preferably, the separation layer membrane pore size of the tubular ceramic membrane element is 30nm-100nm, the membrane channel diameter is 4mm, and the cross-flow velocity is 4m / s-6m / s.

[0012] Preferably, it further includes: an emergency bypass pipeline, which is arranged in parallel with the security filter, with one end connected to the inlet side of the security filter and the other end connected to the suction end of the circulation pump; the emergency bypass pipeline is used to temporarily open when the security filter fails or is under maintenance.

[0013] Preferably, the security filter is provided with a filter basket with a filtration accuracy of 1 mm.

[0014] Preferably, it also includes a container and an electrical control cabinet, wherein the security filter, circulation pump, membrane filter assembly, clear liquid pipeline and concentrate pipeline are all centrally arranged inside the container; the container is equipped with a maintenance door, an inspection door, a transparent observation window and an exhaust fan.

[0015] A method for filtering kitchen waste slurry, which filters kitchen waste slurry based on any of the devices described above, includes the following steps: The security filter receives food waste slurry and intercepts large particles to protect downstream membrane elements; The slurry treated by the security filter enters the circulation pump, which drives it into the membrane filtration module. The tubular ceramic membrane element of the membrane filtration module has a separation layer pore size of 30nm-100nm and a membrane channel diameter of 3mm-5mm. The cross-flow velocity is controlled at 4m / s-6m / s to create turbulence in the slurry within the membrane channel, thereby separating the permeate and concentrate. A portion of the concentrate is returned to the suction end of the circulation pump. The permeate is collected and discharged through the clear liquid pipeline; and A portion of the concentrate is discharged through the concentrate pipeline.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The security filter intercepts and filters kitchen waste slurry, removing large particles (such as bone fragments, fruit pits, and fibers) that accidentally enter the device, eliminating the risk of physical damage to the membrane element and ensuring its long-term stable operation. Furthermore, the membrane pore size of 30nm-100nm precisely matches the particle size distribution of suspended solids and grease in the kitchen waste slurry, achieving highly efficient retention (impurities in the permeate <50mg / L, grease in the permeate <10mg / L), meeting commercial carbon source standards. The small channel diameter of 3mm~5mm allows turbulent flow to be achieved at a moderate cross-flow velocity (4~6m / s), and the turbulent shear force effectively inhibits membrane fouling. The synergistic effect of these three factors gives the device high filtration accuracy, high throughput (50~100 L / h·m²), long cleaning cycles, and low energy consumption, solving the problems of low throughput, easy clogging, and unstable treatment effects in existing technologies.

[0017] 2. This invention is based on the Reynolds number principle: the smaller the pipe diameter, the lower the critical flow velocity required to achieve turbulence. This solution selects a small-diameter channel of 3-5mm (preferably 4mm), which, compared to the conventional 6-8mm channel, achieves the same turbulence intensity at a lower flow velocity, thereby reducing the energy consumption of the circulating pump.

[0018] 3. By installing flow meters and regulating valves on the concentrate and clear liquid pipelines respectively, and combining them with a controller, the concentration ratio can be automatically adjusted. Operators can set the target concentration ratio (such as 2x or 4x) according to actual needs, and the system will automatically maintain stable operation at that ratio. In the low-concentration mode (2x), the membrane flux can reach 80~100L / h·m², with the lowest operating cost, suitable for on-site carbon source production. In the high-concentration mode (4x), the solid content of the concentrate increases to 20%~25%, and the volume is significantly reduced, allowing it to be directly sent to incineration plants or landfills for disposal. There is no need to invest in the construction of anaerobic digestion systems and biogas slurry treatment systems, making it particularly suitable for small and medium-sized kitchen waste treatment projects. This technology achieves the flexibility of "one machine, two modes," significantly reducing the overall investment and operating costs of the project.

[0019] 4. This invention integrates the cleaning tank, cleaning pump, drain pipeline, and switching valve into the filtration device, and automatically executes the cleaning process (drainage → water injection → circulating cleaning → soaking → drainage) through program control. This technology produces the following beneficial effects: ① The cleaning process is automated, eliminating the need for manual disassembly and assembly of membrane elements, significantly reducing maintenance intensity; ② The cleaning solution circulates in a closed loop within the membrane circuit, resulting in high reagent utilization and low cleaning costs; ③ Daily clean water cleaning combined with monthly alkaline cleaning with reagents can effectively restore membrane flux and extend the service life of membrane elements by 2-3 years; ④ The drain pipeline design ensures that residual liquid in the system is completely discharged before cleaning, preventing the slurry from mixing with the cleaning solution and guaranteeing the cleaning effect.

[0020] 5. The modular integrated design integrates the filtration system, cleaning system, and electrical control system into the container, which not only reduces the equipment footprint but also enables full system testing before delivery, greatly shortening the on-site installation and commissioning time. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural schematic diagram (view 1) of the kitchen waste slurry filtration device in an embodiment of the present invention.

[0022] Figure 2 This is a three-dimensional structural schematic diagram (perspective two) of the kitchen waste slurry filtration device in an embodiment of the present invention.

[0023] Figure 3 This is a view of the container's external shape in an embodiment of the present invention (view 1).

[0024] Figure 4 This is a view of the container's external shape (view 2) in an embodiment of the present invention.

[0025] Among them, 100: security filter 110: Water inlet pipe 120: Emergency bypass pipeline 200: Circulation pump 300: Membrane filtration module 310: Episode 1 Liquid Chamber 320: First-stage tubular ceramic membrane element 330: Second-stage tubular ceramic membrane element 340: Episode 2 Liquid Chamber 400: Clean liquid pipeline 500: Concentrate pipeline 610: Concentrate line flow meter 620: Clear Liquid Pipeline Flow Meter 630: Regulating control valve 710: Cleaning Tank 720: Cleaning Pump 730: Water pipes 740: Drainage pipe 800: Container 810: Inspection Gate 820: Inspection gate 830: Transparent viewing window 840: Exhaust Fan 900: Electrical control cabinet. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0027] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0028] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0029] Reference Figure 1 and Figure 2 This invention provides a kitchen waste slurry filtration device. In some embodiments, the kitchen waste slurry filtration device is configured to treat the slurry generated during the pretreatment of kitchen waste (including catering waste, household kitchen waste, and other kitchen waste). This slurry may include slurry generated from hopper and equipment draining, solid-liquid separation slurry, and slurry separated by a three-phase oil extractor. The kitchen waste slurry filtration device according to this invention can effectively remove impurities such as grease and suspended solids, thereby obtaining a carbon source that meets high standards for wastewater treatment. The device mainly includes a security filter 100, a circulation pump 200, a membrane filter assembly 300, a clear liquid pipeline 400, and a concentrate pipeline 500.

[0030] The security filter 100 is configured to receive and filter kitchen waste slurry. The inlet of the security filter 100 is connected to the inlet pipe 110 for receiving the kitchen waste slurry, and the outlet of the security filter 100 is connected to the suction end of the circulation pump 200. The security filter 100 has a filter basket with a filtration accuracy of 1 mm inside, which can effectively intercept coarse particles and fibrous materials in the slurry. The slurry has already undergone preliminary filtration before entering the device. The function of the security filter 100 is to intercept accidentally mixed large particulate impurities to avoid damage to downstream membrane elements. Specifically, the device also includes an emergency bypass pipe 120, which is connected in parallel with the security filter 100, with one end connected to the inlet side of the security filter 100 and the other end connected to the suction end of the circulation pump 200. The emergency bypass pipe 120 is only temporarily opened in case of severe blockage or failure of the security filter 100 or when maintenance is required, to ensure continuous operation of the system.

[0031] The suction end of the circulation pump 200 is connected to the outlet of the security filter 100, and its outlet is connected to the inlet of the membrane filter assembly 300. The circulation pump 200 is configured to drive the kitchen waste slurry to flow through the membrane channels in a cross-flow manner, creating strong turbulence within the membrane channels. Preferably, the cross-flow velocity provided by the circulation pump 200 is 5 m / s, thereby effectively flushing the membrane surface and preventing membrane clogging.

[0032] Turbulence is generated by the combined effect of three factors: flow velocity, channel diameter, and fluid properties (density / viscosity).

[0033] Flow velocity (v): provided by the circulating pump. The higher the flow velocity, the larger the Reynolds number, and the easier it is to form turbulence, resulting in higher energy consumption of the circulating pump. Therefore, an economical flow velocity needs to be selected while meeting the turbulence requirements; in this embodiment, approximately 5 m / s is used.

[0034] Channel diameter (d): The smaller the pipe diameter, the lower the critical flow velocity required to achieve turbulence. This scheme selects a small diameter channel of 3-5mm (preferably 4mm), which achieves the same turbulence intensity at a lower flow velocity compared to the conventional 6-8mm channel, thereby reducing the energy consumption of the circulating pump.

[0035] The membrane filtration assembly 300 includes at least one tubular ceramic membrane element, whose separation layer membrane pore size is 30nm-100nm and membrane channel diameter is 3mm-5mm (preferably 4mm). Through the small-diameter 4mm membrane channel, high turbulence can be formed at a cross-flow velocity of 5m / s. Simultaneously, the 30-100nm membrane pore size effectively traps suspended solids and grease in the slurry. The combined effect achieves high-flux, anti-clogging filtration, reducing overall energy consumption while achieving optimal cross-flow flushing. The tubular ceramic membrane element of this invention employs a cross-flow filtration method. Specifically, the kitchen waste slurry to be treated flows at high speed along the axial direction of the membrane channel, while the clarified liquid passes through the separation layer membrane pores into the collection side along the radial direction (i.e., perpendicular to the axial direction) of the membrane channel. The flow direction of the slurry and the permeation direction of the clarified liquid are intersected, thereby utilizing the shear force generated by the flow to inhibit the deposition of pollutants on the membrane surface. Because the direction of the pores in the separation layer membrane intersects (is basically perpendicular) with the mainstream direction of the slurry in the membrane channel, the horizontal shear force formed by the slurry on the membrane surface can effectively prevent the adhesion of suspended solids and grease at the membrane pore inlet. This is the key structural basis for the invention to achieve long-term high-flux operation. In a specific embodiment, the membrane filtration assembly 300 includes a first-stage tubular ceramic membrane element 320 and a second-stage tubular ceramic membrane element 330 arranged in series, as well as a first collection chamber 310 located at the inlet end of the first stage and a second collection chamber 340 located at the outlet end of the second stage. To accommodate different processing scales, the first-stage tubular ceramic membrane element 320 includes 1-6 membrane elements arranged in parallel, and the second-stage tubular ceramic membrane element 330 includes 1-6 membrane elements arranged in parallel. The kitchen waste slurry is distributed through the first collection chamber 310 and enters the first-stage tubular ceramic membrane element 320. The concentrate flowing through this stage then enters the second-stage tubular ceramic membrane element 330, and the concentrate flowing through the second-stage tubular ceramic membrane element 330 finally flows into the second collection chamber 340. The device also includes a return line that returns at least a portion of the concentrate from the second collection chamber 340 to the suction end of the circulation pump 200 to achieve continuous closed-loop filtration.

[0036] The supernatant line 400 is connected to the supernatant outlet of the tubular ceramic membrane element and is used to discharge the permeate. The concentrate line 500 is connected to the concentrate outlet of the tubular ceramic membrane element (e.g., via the second collection chamber 340) and is used to discharge a portion of the concentrate to maintain material balance.

[0037] Compared to existing flat-plate ceramic membranes, the membrane element of this application uses a tubular ceramic membrane. By maintaining a high flow rate within the tubular ceramic membrane, turbulent and cross-flow filtration is achieved. This is fundamentally different from the dead-end filtration of flat-plate ceramic membranes, and is the most important reason why the filtration flux per unit membrane area of ​​the tubular ceramic membrane is much higher than that of the flat-plate ceramic membrane. In addition, the higher flow rate makes the membrane surface less prone to clogging, allowing the membrane filtration device to maintain high-flux operation for a long time and extending the cleaning cycle.

[0038] The slurry temperature varies in different stages of kitchen waste treatment, ranging from room temperature kitchen waste drainage treatment to three-phase centrifugal slurry treatment above 80°C. Compared with traditional organic membrane elements, tubular ceramic membrane elements can withstand higher temperatures, up to 100°C or more. Slurries at various temperatures can enter the membrane filtration device, solving the problem that traditional organic membranes cannot withstand high temperatures.

[0039] In some embodiments, the apparatus further includes a concentration ratio adjustment system, comprising a concentrate line flow meter 610 disposed on the concentrate line 500, a clear liquid line flow meter 620 disposed on the clear liquid line 400, and adjustment control valves 630 disposed on the two lines respectively. The adjustment control valves 630 are capable of automatically adjusting their opening degree according to the measured values ​​of the two lines to precisely control the concentration ratio of the system at a set value.

[0040] The concentration ratio is defined as the ratio of the feed flow rate to the concentrate discharge flow rate. Under constant feed flow rate conditions, the discharge resistance of the concentrate can be changed by adjusting the opening of the control valve on the concentrate pipeline: closing the valve reduces the amount of concentrate discharged, forcing more slurry in the feed to permeate through the membrane element and become clear liquid, thus increasing the concentration ratio; conversely, opening the valve increases the amount of concentrate discharged, thus decreasing the concentration ratio. The controller calculates the actual concentration ratio based on the real-time reading of the flow meter and compares it with the preset target value. The system automatically adjusts the valve opening to bring the actual concentration ratio closer to the target value.

[0041] This application includes a concentration ratio adjustment system to flexibly adjust the concentration ratio in order to achieve different process objectives.

[0042] If the primary process objective is simply to meet the carbon source requirements for anaerobic digestion of kitchen waste slurry within the plant, the carbon source demand is relatively low. To achieve higher membrane flux and lower operating costs, a lower concentration factor can be controlled, for example, a concentration factor of 2. A lower concentration factor maintains a relatively low suspended solids concentration in the circulation pipeline. Lower suspended solids concentration reduces the concentration polarization effect on the membrane system, thus naturally resulting in a higher membrane flux. The concentrate can be treated in the anaerobic digestion system, while the permeate is sent to the downstream digester system to supplement the carbon source. Practice has shown that at a concentration factor of around 2, the membrane flux can reach 80 L / h. For areas above m2, the lower the concentration factor, the higher the membrane flux.

[0043] The second process objective, if maximizing the output of permeate for use as a carbon source in the wastewater treatment plant, requires controlling the concentration ratio as high as possible. For example, when the concentration ratio reaches 4 times, the solids content of the concentrate is 20-25%, and the membrane flux is still 50 L / h. For areas above m2, the flux is still significantly higher than that of flat sheet membranes and organic membranes. At this point, the concentrate production is greatly reduced and can be disposed of at incineration plants or landfills. This eliminates the need to invest in anaerobic digestion systems and anaerobic slurry treatment systems, greatly reducing project investment and operating costs, making it very suitable for small and medium-sized food waste treatment projects.

[0044] Please refer to the table below, which shows the membrane flux experimental data of the kitchen waste slurry filtration device of this application under different raw materials and different concentration ratios.

[0045]

[0046] To ensure long-term membrane flux, the device also includes an automatic cleaning system configured to circulate the cleaning solution within the device in cleaning mode. The automatic cleaning system includes a cleaning tank 710, a cleaning pump 720, a water supply line 730, and a drain line 740. In cleaning mode, the valves between the drain line 740 and the first collection chamber 310, the second collection chamber 340, and the security filter 100 are opened, connecting the drain line 740 to the bottom of these chambers to drain residual liquid from the device. The inlet of the cleaning pump 720 is connected to the outlet of the cleaning tank 710, and the outlet is connected to the inlet of the security filter 100. The cleaning tank 710 is connected to the water supply line 730, the clarified liquid line 400, and the concentrated liquid line 500, allowing for the collection of water from different sources or the preparation of cleaning solutions. The cleaning solution used can be clean water or an aqueous solution with added sodium hydroxide for better degreasing.

[0047] Normal operating mode Kitchen waste slurry enters the security filter 100 through the inlet pipe 110. A 1mm filter basket intercepts large particles (such as bone fragments, fruit pits, and fibers) to prevent them from entering subsequent equipment. The slurry treated by the security filter enters the circulation pump 200, which pressurizes the slurry to 0.2~0.4MPa, achieving a flow velocity of 4~6m / s at the membrane channel inlet. The slurry flows sequentially through the first-stage tubular ceramic membrane element 320 and the second-stage tubular ceramic membrane element 330, creating well-developed turbulence within the membrane channels. The clarified liquid permeates through the membrane elements and is discharged through the clarified liquid pipe 400. The concentrated liquid, partly returned to the suction end of the circulation pump 200 through the second collection chamber 340, and the other part discharged through the concentrated liquid pipe 500. The concentration ratio can be adjusted by controlling the concentrated liquid discharge flow rate.

[0048] Automatic Concentration Adjustment Mode The concentration ratio is defined as the ratio of the feed flow rate to the concentrate discharge flow rate. Under the condition of constant feed flow rate, the concentration ratio can be changed by adjusting the valve opening on the concentrate pipeline 500: closing the valve reduces the concentrate discharge, so more slurry in the feed is forced to permeate through the membrane to become clear liquid, and the concentration ratio increases; conversely, opening the valve increases the concentrate discharge and decreases the concentration ratio.

[0049] In this embodiment, a first flow meter 610 and a regulating control valve 630 are installed on the concentrate pipeline 500, and a second flow meter 620 and a regulating control valve 630 are installed on the clear liquid pipeline 400. The controller (PLC in the electrical control cabinet) receives the readings of the two flow meters, calculates the actual concentration ratio (actual concentration ratio = feed flow rate ÷ concentrate flow rate, where the feed flow rate can be calculated from the feed flow rate or from the clear liquid flow rate + concentrate flow rate), and compares it with the preset target concentration ratio (such as 2 times or 4 times). It automatically adjusts the valve opening on the concentrate pipeline 500 and / or the clear liquid pipeline 400 to stabilize the actual concentration ratio near the target value.

[0050] Cleaning mode When cleaning is required, first drain the residual liquid in the device through drain pipe 740. Water is then added to the cleaning tank 710 through tap water pipe 730 until the set level is reached. If chemical cleaning is required, sodium hydroxide is added to the cleaning tank 710. The cleaning pump 720 is started, and the cleaning water flows back to the cleaning tank 710 after passing through the switching valves of the inlet pipe 110, security filter 100, circulation pump 200, membrane filter assembly 300, clear liquid pipe 400, and concentrate pipe 500, forming a closed-loop circulation. After the cleaning and soaking time reaches the set value, the cleaning pump 720 is automatically shut off and the wastewater is drained, completing the cleaning process. During routine shutdowns, a clean water rinse is performed, and a chemical alkaline rinse is performed monthly.

[0051] Emergency mode When the security filter 100 becomes clogged or the filter basket requires maintenance and the system cannot be shut down, the emergency bypass line 120 can be temporarily opened to allow the slurry to bypass the security filter 100 and enter the circulation pump 200 directly. This mode should only be used for short-term emergency applications and should not be operated for extended periods to avoid damage to the membrane elements from large particles.

[0052] Reference Figure 3 and Figure 4To improve integration and environmental adaptability, the device also includes a container 800 and an electrical control cabinet 900. The security filter 100, circulation pump 200, membrane filter assembly 300, clarified liquid pipeline 400, and concentrated liquid pipeline 500 are all centrally located within the container 800. The container 800 is equipped with a maintenance door 810, a patrol door 820, a transparent observation window 830, and an exhaust fan 840 for ventilation and heat dissipation.

[0053] The present invention also provides a method for filtering kitchen waste slurry based on the above-mentioned device, comprising the following steps: The security filter receives and filters the slurry from kitchen waste. The slurry treated by the security filter enters the circulation pump, which drives it into the membrane filtration module. The tubular ceramic membrane element of the membrane filtration module has a separation layer pore size of 30nm-100nm and a membrane channel diameter of 3mm-5mm. The cross-flow velocity is controlled at 4m / s-6m / s to create turbulence in the slurry within the membrane channel, thereby separating the permeate and concentrate. A portion of the concentrate is returned to the suction end of the circulation pump. The permeate is collected and discharged through the clear liquid pipeline; and A portion of the concentrate is discharged through the concentrate pipeline.

[0054] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A kitchen waste slurry filtration device, characterized in that, include: A security filter, whose inlet is used to receive food waste slurry, is used to intercept large particles in the food waste slurry to protect downstream membrane elements; A circulating pump, the suction end of which is connected to the outlet of the security filter; A membrane filtration assembly, the inlet of which is connected to the outlet of the circulation pump, the membrane filtration assembly comprising at least one tubular ceramic membrane element, the circulation pump being configured to drive kitchen waste slurry to flow through the membrane channel in a cross-flow manner and to form turbulence within the membrane channel; The clear liquid pipeline is connected to the clear liquid outlet of the membrane module and is used to discharge the permeate; The concentrate pipeline is connected to the concentrate outlet of the membrane module and is used to discharge the concentrate.

2. The kitchen waste slurry filtration device according to claim 1, characterized in that, The membrane filtration assembly includes a first-stage tubular ceramic membrane element and a second-stage tubular ceramic membrane element arranged in series, as well as a first liquid collection chamber located at the inlet end of the first-stage tubular ceramic membrane element and a second liquid collection chamber located at the outlet end of the second-stage tubular ceramic membrane element. The first-stage tubular ceramic membrane element comprises 1-6 membrane elements arranged in parallel, and the second-stage tubular ceramic membrane element comprises 1-6 membrane elements arranged in parallel. The kitchen waste slurry is distributed through the first collection chamber and then enters the first-stage tubular ceramic membrane element. The concentrate flowing through the first-stage tubular ceramic membrane element enters the second-stage tubular ceramic membrane element, and the concentrate flowing through the second-stage tubular ceramic membrane element flows into the second collection chamber. The device also includes a return pipeline configured to return at least a portion of the concentrate from the second collection chamber to the suction end of the circulation pump.

3. The kitchen waste slurry filtration device according to claim 1 or 2, characterized in that, It also includes a concentration ratio adjustment system, which includes a concentrate pipeline flow meter installed on the concentrate pipeline, a clear liquid pipeline flow meter installed on the clear liquid pipeline, and adjustment control valves installed on the concentrate pipeline and the clear liquid pipeline respectively; the adjustment control valves are configured to automatically adjust their opening degree according to the measured values ​​of the concentrate pipeline flow meter and the clear liquid pipeline flow meter, so as to control the concentration ratio at a set value.

4. The kitchen waste slurry filtration device according to claim 2, characterized in that, It also includes an automatic cleaning system configured to circulate the cleaning fluid within the device in cleaning mode; the automatic cleaning system includes a cleaning tank, a cleaning pump, a tap water pipeline, and an emptying pipeline; in cleaning mode, the emptying pipeline is connected to the bottom of the first liquid collection chamber, the second liquid collection chamber, and the security filter for emptying the liquid within the device; the inlet of the cleaning pump is connected to the outlet of the cleaning tank, and the outlet of the cleaning pump is connected to the inlet of the security filter; the cleaning tank is connected to the tap water pipeline, the clear liquid pipeline, and the concentrated liquid pipeline, respectively.

5. The kitchen waste slurry filtration device according to claim 4, characterized in that, The cleaning solution is water or an aqueous solution with added sodium hydroxide.

6. The kitchen waste slurry filtration device according to claim 1, characterized in that, The separation layer membrane pore size of the tubular ceramic membrane element is 30nm-100nm, the membrane channel diameter is 4mm, and the cross-flow velocity is 4m / s-6m / s.

7. The kitchen waste slurry filtration device according to claim 1, characterized in that, Also includes: An emergency bypass line is connected in parallel with the security filter, with one end connected to the inlet side of the security filter and the other end connected to the suction end of the circulation pump; the emergency bypass line is used to temporarily open when the security filter fails or is under maintenance.

8. The kitchen waste slurry filtration device according to claim 1, characterized in that, The security filter is equipped with a filter basket with a filtration accuracy of 1mm.

9. The kitchen waste slurry filtration device according to claim 1, characterized in that, It also includes a container and an electrical control cabinet. The security filter, circulation pump, membrane filter assembly, clear liquid pipeline and concentrate pipeline are all centrally arranged inside the container. The container is equipped with a maintenance door, an inspection door, a transparent observation window and an exhaust fan.

10. A method for filtering kitchen waste slurry, characterized in that, The device described in any one of claims 1-9 filters kitchen waste slurry, comprising the following steps: The security filter receives the food waste slurry and intercepts large particles to protect downstream membrane elements; The slurry treated by the security filter enters the circulation pump, which drives it into the membrane filtration module. The tubular ceramic membrane element of the membrane filtration module has a separation layer pore size of 30nm-100nm and a membrane channel diameter of 3mm-5mm. The cross-flow velocity is controlled at 4m / s-6m / s to create turbulence in the slurry within the membrane channel, thereby separating the permeate and concentrate. A portion of the concentrate is returned to the suction end of the circulation pump. The permeate is collected and discharged through the clear liquid pipeline; as well as A portion of the concentrate is discharged through the concentrate pipeline.

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