Method and system for preparing organic aqueous solution from kitchen waste

Abstract

The application discloses a method for preparing organic matter aqueous solution from kitchen garbage, which removes inorganic sundries in the kitchen garbage by a multi-stage treatment step-by-step reduction mode to obtain kitchen garbage slurry, sterilizes the kitchen garbage slurry by high-temperature stewing sterilization and residue separation to remove difficult-to-dissolve matters in the slurry, and obtains organic matter suspension liquid which is not easy to spoil, breaks the wall of small-particle difficult-to-dissolve matters in the suspension liquid by a wall-breaking homogenization mode, further nanometerizes the small-particle organic matters which are difficult to dissolve in water, suspends the nanometerized small-particle organic matters in the water solution to form a suspension, stores as much organic matter as possible in the water solution to ensure the organic matter content of the organic matter aqueous solution, clarifies the suspension by a filter-pressing mode, filters out sundries and organic matter particles with large particle sizes in the suspension by a filter cloth with small pore diameters, and then obtains the organic matter aqueous solution product suitable for market demands by a desalination mode through an ion exchange membrane and an evaporation mode to remove water and concentrate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of preparing organic matter aqueous solution from kitchen waste, in particular to a method and system for preparing organic matter aqueous solution from kitchen waste. BACKGROUND

[0002] Kitchen waste is a kind of household garbage, which is generated in daily life and food processing, catering service, unit catering and other activities, including discarded vegetable leaves, leftovers, fruit peels, eggshells, tea dregs, bones and the like, and is mainly from household kitchens, restaurants, hotels, canteens, markets and other food processing related industries. Kitchen waste is also called wet garbage or perishable garbage, which contains a high amount of water and organic matter and is easy to rot and produce foul odor.

[0003] Conventional kitchen waste treatment technologies include direct crushing and discharge, landfill, incineration, fertilizerization, feedstuffing, insect breeding and energy production. Direct crushing and discharge of kitchen waste will increase the pressure on urban pipe networks, kitchen waste landfill will cause secondary pollution, kitchen waste incineration will increase additional energy consumption and carbon emissions, kitchen waste fertilizerization and feedstuffing have high costs and odor treatment problems, insect breeding has immature breeding technology and product lack of risk assessment problems, and kitchen waste energy production has low yield, high processing cost and narrow sales channel problems. SUMMARY

[0004] Therefore, in view of the above technical problems, a method and system for preparing organic matter aqueous solution from kitchen waste are provided to solve the problems of low yield, high processing cost and narrow sales channel of existing kitchen waste energy production.

[0005] The present application provides a method for preparing organic matter aqueous solution from kitchen waste, which comprises:

[0006] Slurrying and treating the kitchen waste to remove solid impurities to obtain a first organic slurry; the solid impurities include heavy impurities and light impurities, the heavy impurities include metal, glass, ceramic, bone and eggshell, and the light impurities include plastic and fabric; the solid impurities are compressed into RDF fuel rods;

[0007] Sterilizing the first organic slurry to obtain a second organic slurry;

[0008] Separating and treating the second organic slurry, and separating into solid residue, animal and plant oil and suspension liquid according to the density difference;

[0009] Nanoprocessing the suspension liquid to obtain a suspension by breaking the cell wall and homogenizing;

[0010] The suspension is clarified to remove particles larger than a predetermined particle size in the suspension by filter pressing to obtain a clarified liquid, and the particles larger than the predetermined particle size in the suspension are prepared into filter cakes by a predetermined method;

[0011] The solid residue and the filter cakes are subjected to fermentation treatment to obtain a bio-fermentation material;

[0012] The clarified liquid is subjected to ion exchange membrane desalination to reduce the salt content in the clarified liquid;

[0013] The desalted clarified liquid is concentrated to obtain reclaimed water and an organic aqueous solution.

[0014] In the above scheme, the kitchen waste slurry is optionally treated by slurring and impurities are removed to obtain a first organic slurry, which includes:

[0015] The kitchen waste is treated by stepwise reduction separation to obtain an organic slurry with a particle size of ≤2 mm through at least 2 stages of crushing and 2 stages of separation;

[0016] Or the organic slurry is obtained by stepwise reduction separation through 4 stages of crushing and 3 stages of separation to obtain a slurry with a high conversion rate of organic matter.

[0017] In the above scheme, the first organic slurry is further optionally subjected to sterilization treatment to obtain a second organic slurry, which includes:

[0018] The first organic slurry is sterilized by high-temperature indirect heating and stirring stewing;

[0019] The final heating temperature of the first organic slurry is 100°C, and the holding time of the final temperature is 30-35 minutes.

[0020] In the above scheme, the suspension is further optionally subjected to nanometerization treatment to obtain a suspension by breaking wall homogenization, which includes:

[0021] The solid particles in the suspension are homogenized into smaller particles by pressure loss, expansion, explosion, shearing and high-speed impact by breaking wall homogenization, and the nanometerized solid particles are suspended in water;

[0022] The temperature of the suspension during nanometerization treatment is 55-65°C;

[0023] The particle size of more than 95% of the particles in the suspension after nanometerization treatment is ≤1 μm.

[0024] In the above scheme, the suspension is further optionally subjected to clarification treatment, which includes:

[0025] The particles larger than a predetermined particle size in the suspension are filtered out by high-pressure filter pressing.

[0026] The air permeation amount of the filter cloth of the high-pressure filter press is 90-200 L / m 2 ·s;

[0027] The feeding pressure of the high-pressure filter press is ≥8 kg / cm 2 ;

[0028] The pressing pressure of the high-pressure filter press is raised to ≥4 kg / cm 2 , the compressed air is blown when the pressing pressure is ≥4 kg / cm 2 , the blowing pressure of the compressed air is ≥10 kg / cm, and the blowing time is 5-8 min.

[0029] The pressing pressure of the high-pressure filter press is ≥20 kg / cm 2 , and the pressing time is 15-18 min.

[0030] In the above scheme, further optionally, the clarified liquid is desalted by an ion exchange membrane to reduce the salt content in the clarified liquid, comprising:

[0031] The desalination method of the clarified liquid is an electrodialysis method, through the selective permeability of the semi-permeable membrane, the salt concentration of the clarified liquid is reduced due to the directional migration of the anions and cations constituting the salt.

[0032] In the above scheme, further optionally, the desalted clarified liquid is concentrated to obtain regenerated water and an organic water solution, comprising:

[0033] The concentration treatment method of the clarified liquid adopts a low-temperature evaporation method, the evaporated water is cooled and treated by a membrane to obtain the regenerated water.

[0034] The total organic matter in the concentrated organic water solution is ≥100 g / L.

[0035] The present application has at least the following beneficial effects:

[0036] This invention, based on further analysis and research into existing technological problems, recognizes that conventional food waste treatment technologies include direct discharge after pulverization, landfill, incineration, fertilizer production, feed production, insect farming, and energy production. Direct discharge of pulverized food waste increases pressure on urban pipe networks; landfilling food waste causes secondary pollution; incineration increases additional energy consumption and carbon emissions; insect farming suffers from immature breeding technology and a lack of risk assessment for products; and food waste energy production suffers from low yield, high processing costs, and limited sales channels. This application proposes a resource-based approach to food waste treatment, converting it into RDF fuel rods, bio-oil fuels, bio-fermentation materials, reclaimed water, and organic matter aqueous solutions. Utilizing relatively simple industrial production line equipment and low energy consumption, marketable products are obtained. This approach not only practices the energy-saving and emission-reduction principle of "returning to where it came from" in waste treatment but also ensures the operational efficiency of disposal companies, possessing broad market potential.

[0037] This application describes the resource-based treatment of kitchen waste into an organic aqueous solution. This organic aqueous solution is rich in organic matter and can be used as a raw material for hydrolysis to prepare water-soluble fertilizers, for catalytic acid hydrolysis to prepare organic acids, and can also be directly applied to soil remediation and wastewater treatment, showing broad market application prospects. The preparation of the organic aqueous solution will generate some byproducts, which can be further processed to produce value-added products such as RDF fuel rods, bio-oil fuels, bio-fermentation materials, and reclaimed water.

[0038] This application first liquefies kitchen waste into a slurry, removing inorganic matter through multi-stage treatment and volume reduction to obtain a kitchen waste slurry suitable for preparing an organic aqueous solution. High-temperature sterilization and residue separation are used to inactivate bacteria, viruses, and parasite eggs in the kitchen waste slurry, removing insoluble substances and obtaining a slurry of organic matter that is not easily perishable. The organic suspension is then homogenized by cell wall disruption to break down and homogenize small, insoluble particles, allowing water-soluble organic matter to dissolve in water. The insoluble small particles are further nano-sized, forming a suspension that retains as much organic matter as possible in the aqueous solution to ensure a high organic matter content. The organic suspension is then clarified by filtration, using a small-pore filter cloth to remove impurities and larger organic particles. Finally, it is desalted through an ion exchange membrane and concentrated by evaporation to obtain an organic aqueous solution product suitable for market demand. Attached Figure Description

[0039] Figure 1 This is a schematic flowchart of a method for preparing an organic aqueous solution from kitchen waste according to an embodiment of the present invention;

[0040] Figure 2A process flow diagram of a method for preparing an organic aqueous solution from kitchen waste, provided in one embodiment of the present invention;

[0041] Figure 3 This is a process flow diagram of a method for preparing an organic aqueous solution from kitchen waste, provided as an embodiment of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0043] The method for preparing an organic aqueous solution from kitchen waste provided in this application, such as Figure 1 As shown, it includes the following steps:

[0044] The kitchen waste is liquefied and solid impurities are removed to obtain a first organic slurry; the solid impurities include heavy impurities and light impurities, the heavy impurities include: metal, glass, ceramics, bones and eggshells, and the light impurities include plastics and textiles; the solid impurities are compressed to make RDF fuel rods;

[0045] The first organic slurry is sterilized to obtain a second organic slurry.

[0046] The second organic slurry is separated into solid residue, animal and vegetable oils, and suspension based on density differences.

[0047] The suspension is nano-sized and then homogenized to obtain a mixed suspension.

[0048] The suspension is clarified by removing particles larger than a preset particle size from the suspension through filtration to obtain a clarified liquid. The particles larger than the preset particle size in the suspension are made into a filter cake by a preset method.

[0049] The solid residue and the filter cake are fermented to prepare a biological fermentation material.

[0050] The clarified liquid is desalted using an ion exchange membrane to reduce the salt content in the clarified liquid;

[0051] The clarified liquid after desalination is concentrated to obtain reclaimed water and an aqueous solution of organic matter.

[0052] In this embodiment, the process of liquefying kitchen waste slurry and removing impurities to obtain a first organic slurry includes:

[0053] The kitchen waste is processed into an organic slurry with a particle size of ≤2mm by a step-by-step reduction and separation method, through at least two stages of crushing and two stages of sorting.

[0054] Alternatively, an organic slurry can be prepared by a step-by-step reduction separation method consisting of 4-stage crushing and 3-stage sorting, resulting in a slurry with a high organic conversion rate.

[0055] In this embodiment, the first organic slurry is sterilized to obtain a second organic slurry, comprising:

[0056] The first organic slurry was sterilized by a high-temperature indirect heating and stirring simmering method;

[0057] The final heating temperature of the first organic slurry is 100°C, and the final temperature is maintained for 30-35 minutes.

[0058] In this embodiment, the process of nano-sizing the suspension and then homogenizing it to obtain a suspension includes:

[0059] By employing a cell wall breaking and homogenization method, the solid particles in the suspension are homogenized into smaller particles through decompression, expansion, explosion, shearing, and high-speed impact. The nano-sized solid particles are suspended in water.

[0060] The temperature of the suspension during the nano-sizing process is 55~65℃;

[0061] The nano-sized suspension particles have a particle size of ≤1μm for more than 95% of them.

[0062] In this embodiment, the suspension is clarified, specifically as follows:

[0063] High-pressure filtration is used to filter out particles larger than a preset particle size from the suspension.

[0064] The air permeability of the filter cloth used in the high-pressure filter press is 90~200 L / m. 2 ·s;

[0065] The feed pressure of the high-pressure filter press is ≥8 kg / cm². 2；

[0066] The pressing pressure of the high-pressure filter press is increased to ≥4 kg / cm². 2 Start blowing compressed air at this time, with a purging pressure ≥10 kg / cm². 2 Purging time: 5-8 minutes;

[0067] The pressing pressure of the high-pressure filter is ≥20 kg / cm². 2 The pressing time is 15-18 minutes.

[0068] In this embodiment, desalting the clarified liquid using an ion exchange membrane to reduce the salt content in the clarified liquid includes:

[0069] The method for desalting the clarified solution is to use electrodialysis. Through the selective permeability of the semi-permeable membrane, the salt concentration of the clarified solution is reduced due to the directional migration of the anions and cations that make up the salt.

[0070] In this embodiment, the clarified desalinated liquid is concentrated to obtain a reclaimed water and an aqueous solution of organic matter, comprising:

[0071] The clarified liquid concentration treatment method adopts low-temperature evaporation, and the evaporated water is cooled and then treated by membrane to obtain the reclaimed water.

[0072] The total organic matter in the concentrated organic aqueous solution is ≥100g / L.

[0073] This embodiment first liquefies kitchen waste into a slurry, removing inorganic matter through multi-stage processing and volume reduction to obtain a kitchen waste slurry suitable for preparing an organic aqueous solution. High-temperature sterilization and residue separation are used to inactivate bacteria, viruses, and parasite eggs in the slurry, removing insoluble substances and yielding an organic suspension that is less prone to spoilage. The organic suspension is then homogenized to break down small, insoluble particles, allowing water-soluble organics to dissolve. These insoluble particles are further nano-sized, forming a suspension that retains as much organic matter as possible in the aqueous solution. The organic suspension is then clarified by filtration, using a small-pore filter cloth to remove impurities and larger organic particles. It is then desalted using an ion exchange membrane and finally concentrated by evaporation to obtain an organic aqueous solution product suitable for market demand.

[0074] In one embodiment, a process for preparing an organic aqueous solution from kitchen waste is provided, the method comprising the following steps:

[0075] S1: The kitchen waste is liquefied and treated to obtain an organic slurry that removes heavy impurities such as metal, glass, ceramics, bones, and eggshells, as well as light impurities such as plastics and textiles, through crushing, screening, high-speed rotary screening, and sedimentation removal of heavy impurities; the solid impurities separated during the kitchen waste liquefaction process are compressed into RDF fuel rods.

[0076] S2: The organic slurry is sterilized by high-temperature cooking, which effectively inactivates various bacteria, viruses and parasite eggs carried by kitchen waste. At the same time, it can also promote the demulsification of the slurry, reduce the viscosity of the slurry, and increase the density difference between oil and water.

[0077] S3: Separate the organic slurry into solid residue, animal and vegetable oils, and suspension based on density differences; sell the animal and vegetable oils separated by centrifugation as raw materials for biofuel.

[0078] S4: The suspension is nano-sized and then homogenized to form a suspension.

[0079] S5: Clarify the suspension by removing macromolecular substances from the suspension through filtration and pressing to obtain a clarified liquid;

[0080] S6: The solid residue separated from S3 and the filter cake produced by S5 are fermented and prepared into bio-fermented material by microbial oxygen-controlled fermentation and drying. The bio-fermented material can be used in poultry and aquatic feed industries or soil improvement.

[0081] S7: Desalinate the clarified liquid separated from S5 using an ion exchange membrane to reduce the salt content in the clarified liquid;

[0082] S8: Concentrate the clarified liquid after desalination in S7 to obtain reclaimed water and an organic matter aqueous solution. The reclaimed water can be reused as greywater, and the organic matter aqueous solution can be used in industries such as water-soluble fertilizer preparation, aquaculture nutrient solution preparation, and carbon source preparation.

[0083] In this embodiment, the method for treating kitchen waste slurry described in S1 adopts a step-by-step reduction and separation approach, which involves at least two stages of crushing and two stages of sorting to produce an organic slurry with a particle size ≤2mm.

[0084] In this embodiment, an organic slurry is prepared by a step-by-step reduction separation method consisting of 4-stage crushing and 3-stage sorting, which can stabilize the equipment operation and improve the degree of automation, resulting in a slurry with a high organic conversion rate.

[0085] In this embodiment, the first-stage crushing adopts a fragmentation method, and the particle size of the crushed kitchen waste is ≤200mm.

[0086] In this embodiment, the second-stage crushing adopts a pendulum impact method, and the crushed kitchen waste is subjected to the first-stage sorting. The mesh size of the first-stage sorting equipment is 40-60mm.

[0087] In this embodiment, the third-stage crushing is carried out by hammer or blade cutting. The crushed kitchen waste is then sorted in the second stage, which uses density difference separation to remove heavy impurities from the slurry.

[0088] In this embodiment, the fourth-stage crushing is carried out by hammer or blade cutting, and the crushed kitchen waste is sorted in the third stage. The mesh size of the third-stage sorting equipment is ≤2mm.

[0089] In this embodiment, the method for sterilizing the organic slurry described in S2 uses a simmering method of "high-temperature indirect heating + stirring" to sterilize the organic slurry.

[0090] In this embodiment, the final heating temperature of the organic slurry is 100°C, and the final temperature is maintained for 30-35 minutes.

[0091] In this embodiment, the nano-processing method described in S4 employs a cell wall disruption and homogenization process. Solid particles in the suspension are homogenized into smaller particles through decompression, expansion, explosion, shearing, and high-speed impact. The nano-sized solid particles can be suspended in water.

[0092] In this embodiment, the temperature of the suspension during the nano-sizing process is 55~65℃.

[0093] In this embodiment, more than 95% of the nano-sized suspension particles have a particle size of ≤1μm.

[0094] In this embodiment, the suspension clarification method described in S5 uses high-pressure filtration to filter out larger particles in the suspension.

[0095] In this embodiment, the air permeability of the filter cloth used in the high-pressure filter press is 90~200 L / m. 2 ·s.

[0096] In this embodiment, the feed pressure of the high-pressure filter press is ≥8 kg / cm². 2 The pressing pressure of the high-pressure filter press is increased to ≥4 kg / cm². 2 Start blowing compressed air at this time, with a purging pressure ≥10 kg / cm². 2 The purging time is 5-8 minutes.

[0097] In this embodiment, the pressing pressure of the high-pressure filter press is ≥20 kg / cm². 2 The pressing time is 15-18 minutes.

[0098] In this embodiment, the method for desalting the clarified liquid described in S7 is to use electrodialysis. Through the selective permeability of the semi-permeable membrane, the salt concentration of the clarified liquid is reduced due to the directional migration of the anions and cations that make up the salt, and the salt content will be <0.1%.

[0099] In this embodiment, the method for concentrating the clarified liquid after desalination described in S8 uses low-temperature evaporation. The evaporated water is cooled and then treated by a membrane to obtain reclaimed water. The total organic matter in the concentrated organic aqueous solution is ≥100g / L.

[0100] In this embodiment, the nano-sizing process described in S4 is achieved through a cell-wall breaking and homogenizing device. The cell-wall breaking and homogenizing device includes: a feed pump, a cooling coil, a temperature control valve, a temperature sensor, a machine body, a feed inlet, a feed valve, a pressure sensor, a pressure chamber, a pressure piston, a piston drive device, an adjustable pressure chamber annular outlet, a tungsten carbide impact ring, a discharge valve, and a discharge port.

[0101] Wherein: the feed pump is connected to the cooling coil, the cooling coil is connected to the temperature control valve, the temperature control valve is connected to the feed inlet through a pipe, and the temperature sensor is installed near the feed inlet; the temperature control valve controls the opening degree according to the temperature sensor to cool the suspension in the cooling coil and ensure that the temperature of the suspension at the feed inlet is the set temperature.

[0102] The feed inlet, feed valve, pressure sensor, pressure chamber, pressure piston, adjustable pressure chamber annular outlet, tungsten carbide impact ring, discharge valve, and discharge port are all mounted on the machine body. The feed valve, pressure sensor, pressure chamber, pressure piston, adjustable pressure chamber annular outlet, tungsten carbide impact ring, and discharge valve are used in combination to form a cell-wall breaking and homogenizing valve group. The cell-wall breaking and homogenizing device has multiple cell-wall breaking and homogenizing valve groups, which are used in a cyclical manner. The piston drive device is connected to the pressure piston mounted on the machine body.

[0103] Wherein: the feed inlet and the discharge outlet are connected to multiple wall-breaking and homogenizing valve groups; a pressure sensor is installed on the pressure chamber to detect the pressure inside the pressure chamber; and a piston drive device drives the pressure piston to move inside the pressure chamber.

[0104] Wherein: the adjustable pressure chamber annular outlet is connected to the pressure chamber, the tungsten carbide impact ring is installed near the adjustable pressure chamber annular outlet, the discharge valve is installed at the rear of the tungsten carbide impact ring, and the discharge valve is installed in front of the discharge port; the discharge port is connected to the subsequent equipment, and the suspension after cell wall breaking and homogenization is discharged from the discharge port to the subsequent equipment;

[0105] When the feed pump is turned on, the feed valve of a cell-breaking and homogenizing valve group opens, the discharge valve closes, and the annular outlet of the adjustable pressure chamber closes. The suspension, having reached the set temperature, enters the pressure chamber under the combined action of the pump pressure and the suction of the pressure piston. When the pressure chamber is full, the feed valve closes, the discharge valve opens, and the piston drive device drives the piston to pressurize the suspension in the pressure chamber. The pressurized suspension is discharged from the annular outlet of the adjustable pressure chamber, releasing from a high-pressure state to a zero-pressure state. The solid particles in the suspension undergo depressurization, expansion, explosion, and shearing processes before being ejected at high speed and impacting the tungsten carbide impact ring, breaking down and homogenizing them into nano-sized particles. Multiple cell-breaking and homogenizing valve groups work in a cycle to break down and homogenize the large-particle suspension into a nano-sized suspension, which is then discharged from the drain port.

[0106] This embodiment proposes a resource-based approach to food waste treatment, converting food waste into RDF fuel rods, bio-oil fuel, bio-fermentation feed, reclaimed water, and organic matter aqueous solutions. This approach utilizes relatively simple industrial production line equipment and low energy consumption to produce marketable products. It not only practices the energy-saving and emission-reduction concept of "returning to where it came from" in waste treatment but also ensures the operational efficiency of disposal companies, thus possessing broad market promotion value.

[0107] The key point of this embodiment is to process kitchen waste into an organic aqueous solution. This organic aqueous solution is rich in organic matter and can be used as a raw material for hydrolysis to prepare water-soluble fertilizers, for catalytic acid hydrolysis to prepare organic acids, and can also be directly applied to soil remediation and wastewater treatment, showing broad market application prospects. During the preparation of the organic aqueous solution, some byproducts are generated. These byproducts can be further processed to produce value-added products such as RDF fuel rods, bio-oil fuels, bio-fermentation materials, and reclaimed water.

[0108] This embodiment first liquefies kitchen waste into a slurry, removing inorganic matter through multi-stage processing to obtain a slurry suitable for preparing an organic aqueous solution. High-temperature sterilization and residue separation are used to inactivate bacteria, viruses, and parasite eggs in the slurry, removing insoluble substances and yielding a suspension of organic matter that is less prone to spoilage. The organic suspension is then homogenized to break down small, insoluble particles, allowing water-soluble organic matter to dissolve. These insoluble particles are further nano-sized, forming a suspension that retains as much organic matter as possible in the aqueous solution. The organic suspension is then clarified by filtration, using a small-pore filter cloth to remove impurities and larger organic particles. It is then desalted using an ion exchange membrane and finally concentrated by evaporation to obtain an organic aqueous solution product suitable for market demand.

[0109] In one embodiment, such as Figures 2-3 As shown, this embodiment provides a method for preparing organic aqueous solutions from kitchen waste, which can recycle kitchen waste into products such as RDF fuel rods, bio-oil fuels, bio-fermentation materials, reclaimed water, and organic aqueous solutions. It is an exploration to promote the healthy development of the kitchen waste disposal industry with a product-oriented and market-oriented mindset.

[0110] In this embodiment, S1: The kitchen waste slurry is liquefied.

[0111] After centralized collection, kitchen waste is conveyed to the first-stage crushing equipment. Large-diameter and long-sized kitchen waste is crushed into solids of uniform size of about 150mm. This reduces the impact of large-diameter and long-sized fixed objects on the conveying equipment and the first-stage crushing and sorting equipment, reduces the degree of human intervention in the equipment, and improves the operational stability and automation level of the equipment.

[0112] After being crushed by the first-stage crushing equipment, the kitchen waste is conveyed to the second-stage crushing and first-stage sorting equipment. The kitchen waste is then gently crushed, and the particle size of the organic matter in the kitchen waste is further reduced to about 50mm. Some difficult-to-crush materials such as metals, plastics, textiles, bamboo and wood will be sorted out and transported to the solid waste storage equipment.

[0113] The kitchen waste processed by the first-stage sorting equipment is conveyed to the third-stage crushing equipment. The solids in the kitchen waste are further crushed by the hammers or blades of the crushing equipment, turning it into a slurry with a particle size of ≤10mm.

[0114] The slurry from the third-stage crushing equipment is conveyed to the second-stage sorting equipment, where heavy impurities such as metals, glass, ceramics, stones, bones, shells, and eggshells with higher density are separated by sedimentation and then transported to the solid slag storage equipment.

[0115] The slurry after the second-stage sorting equipment is conveyed to the fourth-stage crushing equipment, where the particle size of organic matter in the slurry is further reduced, and the particle size of the slurry will be ≤4mm.

[0116] The slurry from the fourth-stage crushing equipment is conveyed to the third-stage sorting equipment, where large-sized bamboo, wood, chili seeds, wood fibers and other difficult-to-crush materials are screened out and conveyed to the solid slag storage equipment.

[0117] Solid debris collected by solid slag storage equipment can be granulated into RDF fuel rods and sold as an alternative fuel.

[0118] At this point, the kitchen waste will be completely liquefied, turning into an organic slurry with inorganic matter of ≤2mm particle size removed as much as possible.

[0119] In this embodiment, S2: sterilization treatment of organic slurry.

[0120] The liquefied organic slurry from kitchen waste is injected into a cooking tank. The cooking tank is heated by a jacket or coil, with steam or heat transfer oil injected into the jacket or coil. The organic slurry gradually heats up under the action of the stirring blades in the cooking tank, reaching a temperature of 100°C and maintaining it for 30 minutes. Various bacteria, viruses, and parasite eggs in the organic slurry will be inactivated, and the viscosity of the organic slurry will decrease, while its fluidity will increase.

[0121] In this embodiment, S3: organic slurry separation treatment.

[0122] After sterilization, the organic slurry is discharged from the cooking tank and pumped to a horizontal screw centrifuge for separation. Based on density differences, it is separated into solid residue, animal and vegetable oils, and suspension. The solid residue is stored in a buffer tank for fermentation; the animal and vegetable oils are stored in an oil tank and, after accumulating to a certain quantity, will be sold as raw material for biofuel; the suspension is stored in the buffer tank.

[0123] In this embodiment, S4: suspension nano-sizing treatment.

[0124] The suspension in the S3 buffer tank is pumped to the cell-wall breaking and homogenizing device. Before pumping, the organic slurry from S1, which has been liquefied, is preheated to a temperature of 60°C. The inlet pressure of the cell-wall breaking and homogenizing device is 6 bar, and the operating pressure is 20 MPa. The solid particles in the suspension are broken down and homogenized into a suspension of smaller nano-sized particles through decompression, expansion, explosion, shearing, and high-speed impact, and then stored in the buffer tank. The vast majority of the solid particles in the suspension are ≤100 nm in diameter and remain suspended in the aqueous solution, forming a pseudo-solution.

[0125] In this embodiment, S5: Clarification treatment of the suspension.

[0126] The suspension in S4 is pumped to a high-pressure diaphragm filter press for filtration. The high-pressure diaphragm filter press is selected with an air permeability of 150 L / m³. 2 The filter cloth has a pressure of 8 kg / cm², and the feed pump pressure of the high-pressure diaphragm filter press is 8 kg / cm². 2 The suspension is pumped into the high-pressure diaphragm filter press. As the feed rate increases, the pressure of the feed pump gradually increases. When the feed pressure rises to 4 kg / cm³, the pressure reaches a maximum of 4 kg / cm³. 2 Start blowing compressed air at a pressure of 10 kg / cm². 2 The purging time is 15 minutes. When the feed pump pressure reaches 8 kg / cm³... 2 Continue feeding for 10 minutes, then stop feeding. Start the high-pressure press; when the pressing force reaches 20 kg / cm³... 2 Stop increasing the pressure and maintain it at 20 kg / cm². 2 After pressing for 15 minutes, high-pressure air flow begins, and the material is unloaded after the flow is completed.

[0127] After the high-pressure diaphragm filter press unloads the material and the filter cake is collected, the filter cloth is cleaned. The cleaning solution can be the clarified liquid after filtration by the high-pressure diaphragm filter press. The filter cloth cleaning solution is collected and enters the suspension buffer tank of S5 for recycling.

[0128] In this embodiment, S6: Organic solid residue oxygen-controlled fermentation treatment.

[0129] The solid residue separated from S3 and the filter cake produced from S5 are subjected to microbial controlled-oxygen fermentation and drying. Some auxiliary materials are added to adjust the moisture content of the organic solid residue to 60% and the carbon-to-nitrogen ratio to 25:1. Then, microbial inoculants are added, and the organic solid residue is heated to 70°C using an external heat source. After 6 hours of controlled-oxygen fermentation, it is dried at low temperature for another 3 hours to obtain the bio-fermented material. The bio-fermented material can be further processed to produce commercially available products such as soil conditioners, microbial inoculants, and feed additives.

[0130] In this embodiment, S7: Desalination of the clarified liquid.

[0131] The clarified liquid separated from S5 is pumped to the electrodialysis equipment. The clarified liquid passes through the middle compartment of the ion exchange membrane. The anions and cations that make up the salt move towards the electrodes in opposite directions under the action of the DC electric field. The salt concentration decreases due to the directional migration of ions, thus achieving the purpose of desalination of the clarified liquid.

[0132] In this embodiment, S8: Concentration of clarified liquid.

[0133] The clarified liquid after desalination of S7 is pumped to the preheater of MVR falling film evaporator. The preheated clarified liquid enters the evaporator and is evaporated and concentrated in the evaporator. The organic matter content in the clarified liquid increases. When the organic matter content reaches 120g / L, it is discharged from the bottom of the evaporator to obtain water-soluble fertilizer slurry. The slurry is then processed by the fertilizer blending system to produce water-soluble fertilizer products containing nitrogen, phosphorus, potassium and trace elements.

[0134] The clarified liquid can be concentrated according to the needs of market products. The organic matter content is generally ≤300g / L. During the concentration process of the clarified liquid, some of the steam will condense into condensate, which becomes reclaimed water after simple membrane filtration. The reclaimed water can be reused as greywater.

[0135] This embodiment has the following advantages: It adopts an industrialized, resource-oriented, and market-driven approach, processing kitchen waste into value-added products such as RDF fuel rods, bio-oil fuels, bio-fermentation materials, reclaimed water, and organic matter aqueous solutions using continuous industrial production line equipment. These products can be sold directly or after secondary processing, creating economic value for enterprises. The liquefaction of kitchen waste employs a step-by-step reduction separation method involving four-stage crushing and three-stage sorting to produce organic slurry. This ensures the removal rate of both light inorganic materials (such as plastics and textiles) and heavy inorganic materials (such as metals, glass, ceramics, stones, bones, shells, and eggshells), while also guaranteeing the equipment's processing capacity. The organic slurry is sterilized using a simmering method. The heating medium and the organic slurry are non-contact; the slurry volume is not increased or diluted during simmering. The simmering process uses a medium-high temperature for a relatively long time, which inactivates bacteria, viruses, and parasite eggs, while preventing the high-temperature denaturation of some organic matter in the slurry. The suspension derived from kitchen waste undergoes nano-processing, involving cell wall disruption and homogenization of organic particles. This process maximizes the dissolution of water-soluble organic matter and ensures that insoluble organic matter remains suspended at the nanoscale, improving the utilization rate of organic matter. The suspension is then clarified through filtration, using a small-pore filter cloth to remove larger, easily precipitated organic particles, resulting in an aqueous solution with low impurity levels. Electrodialysis is used to desalinate the organic solution, preventing salt accumulation after concentration and ensuring product quality. Finally, MVR (Medium-Vacuum Reduction) falling film evaporation is employed to concentrate the organic solution, producing a product with an organic content suitable for market demand. This approach ensures product quality while reducing manufacturing costs.

[0136] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0137] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing an organic aqueous solution from kitchen waste, characterized in that, The method includes: The kitchen waste is liquefied and solid impurities are removed to obtain a first organic slurry. The solid impurities are then compressed to make RDF fuel rods. The first organic slurry is sterilized to obtain a second organic slurry. The second organic slurry is separated into solid residue, animal and vegetable oils, and suspension based on density differences. The suspension is nano-sized and then homogenized to obtain a mixed suspension. The suspension is clarified by removing particles larger than a preset particle size from the suspension through filtration to obtain a clarified liquid. The particles larger than the preset particle size in the suspension are made into a filter cake by a preset method. The solid residue and the filter cake are fermented to prepare a bio-fermented material. The clarified liquid is desalted using an ion exchange membrane, and the desalted clarified liquid is concentrated to obtain reclaimed water and an aqueous solution of organic matter; The process of nano-sizing the suspension and then homogenizing it to obtain a suspension includes: By employing a cell wall breaking and homogenization method, the solid particles in the suspension are homogenized into smaller particles through decompression, expansion, explosion, shearing, and high-speed impact. The nano-sized solid particles are suspended in water. The temperature of the suspension during the nano-sizing process is 55~65℃; More than 95% of the nano-sized suspension particles have a particle size of ≤1μm. The suspension is clarified, specifically by: High-pressure filtration is used to filter out particles larger than a preset particle size from the suspension. The air permeability of the filter cloth used in the high-pressure filter press is 90~200 L / m. 2 ·s; The feed pressure of the high-pressure filter press is ≥8 kg / cm². 2 ; The pressing pressure of the high-pressure filter press is increased to ≥4 kg / cm². 2 Start blowing compressed air, with a blowing pressure ≥10kg / cm2 and a blowing time of 5~8min; The high-pressure filter press has a pressing pressure of ≥20kg / cm2 and a pressing time of 15~18min.

2. The method according to claim 1, characterized in that, The process of liquefying kitchen waste into a slurry and removing solid impurities to obtain a first organic slurry includes: By adopting a step-by-step reduction and separation method, the kitchen waste is made into an organic slurry with a particle size of ≤2mm through at least two stages of crushing and two stages of sorting.

3. The method according to claim 1, characterized in that, The first organic slurry is sterilized to obtain a second organic slurry, comprising: The first organic slurry was sterilized by a high-temperature indirect heating and stirring simmering method; The final heating temperature of the first organic slurry is 100°C, and the final temperature is maintained for 30-35 minutes.

4. The method according to claim 1, characterized in that, The clarified desalinated solution is concentrated to obtain an aqueous solution of reclaimed water and organic matter, comprising: The clarified liquid concentration treatment method adopts low-temperature evaporation, and the evaporated water is cooled and then treated by membrane to obtain the reclaimed water. The total organic matter in the concentrated aqueous solution of the organic matter is ≥100g / L.

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