Equipment and method for preparing carbon source from kitchen waste with high efficiency fermentation

Abstract

The present invention discloses a kitchen waste efficient fermentation carbon source preparation device, comprising a kitchen waste pretreatment device for heating and oil-water separation of pre-crushed kitchen waste, the kitchen waste pretreatment device is connected to a fermentation reactor through a water distribution pipe, the fermentation reactor is provided with a gas stirring device and a three-phase separator from bottom to top, the top of the fermentation reactor is connected to a gas-liquid separation tower, and the three-phase separator is connected to the gas-liquid separation tower. The present invention also discloses a kitchen waste efficient fermentation carbon source preparation method, which can hydrolyze and acidify organic matter in kitchen waste to form a fermentation liquid rich in volatile fatty acids, which is used as a very effective external carbon source for a sewage biological treatment unit, and is applied to the sewage treatment field to achieve industrial application.

Description

Technical Field

[0001] The present invention belongs to the technical field of garbage resource processing methods, relates to equipment for preparing a carbon source from kitchen waste with high efficiency fermentation, and also relates to a method for preparing the equipment for preparing a carbon source from kitchen waste with high efficiency fermentation. Background Art

[0002] Kitchen waste has the characteristics of high water content, high organic matter, high salt content, high oil content and easy to rot. If it is not handled in time, it is easy to produce bad odor and breed pathogenic microorganisms, causing environmental pollution problems. The high N content of kitchen waste in my country leads to its low C / N (10-20). If biological methods are used to treat kitchen waste, it is necessary to consider the coordinated treatment of kitchen waste and other high C / N organic wastes. In addition, the unique and rich dietary habits have led to the characteristics of high lipids (17.02%-31.80%), high salt (0.50%-5.00%) and high pepper (0%-2.50%) in my country's kitchen waste. Therefore, in the resource treatment process of kitchen waste in China, the effects of high oil, high salt and high capsaicin should be considered.

[0003] At present, kitchen waste is usually disposed of in landfills and incineration together with urban domestic waste, which brings about secondary pollution problems such as leachate pollution, dioxin and greenhouse gas emissions. More and more countries in the world have begun to ban kitchen waste from entering landfills and separate kitchen waste from domestic waste, thereby improving the efficiency of dry waste incineration power generation. Kitchen waste has a high recycling value, and its resource recovery has gradually become the most promising treatment mode. The ways to utilize kitchen waste resources include feed making, insect breeding and composting. However, insect breeding still has shortcomings such as immature insect breeding technology and lack of risk assessment of the final product. In addition, the high salt and oil content in kitchen waste is not conducive to insect growth. Therefore, this technology has not yet been widely promoted and applied. Anaerobic digestion and aerobic composting are the most widely used resource recovery technologies in industry. They are suitable for centralized large-scale treatment and decentralized, small and medium-scale, source reduction treatment scenarios, respectively. Among them, anaerobic digestion technology has good economic and environmental benefits. The direct use of kitchen waste as animal feed has been expressly prohibited by the state. Kitchen waste must be disinfected, processed and bio-converted before it can be used as feed resources. The methods of recycling kitchen waste feed resources include high temperature disinfection and biological treatment. The above methods have complicated resource processing steps and the application scope of the final product is limited, so it is difficult to achieve industrial application in the short term. Summary of the invention

[0004] The purpose of the present invention is to provide a kitchen waste efficient fermentation carbon source preparation device, which solves the problem that the resource processing method in the prior art is difficult to achieve industrial application.

[0005] The technical solution adopted by the present invention is a high-efficiency kitchen waste fermentation carbon source preparation device, including a kitchen waste pretreatment device for heating and oil-water separation of pre-crushed kitchen waste, the kitchen waste pretreatment device is connected to a fermentation reactor through a water distribution pipe, the fermentation reactor is provided with a gas stirring device and a three-phase separator from bottom to top, the top of the fermentation reactor is connected to a gas-liquid separation tower, and the three-phase separator is connected to the gas-liquid separation tower.

[0006] The present invention is also characterized in that:

[0007] The fermentation reactor includes a reactor body, and the three-phase separator includes a primary three-phase separator. The primary three-phase separator is connected to a gas-liquid separation tower. A central reflux pipe is connected to the bottom of the gas-liquid separation tower. The central reflux pipe extends into the reactor body, and the outlet is located between the water distribution pipe and the gas stirring device. A primary gas seal is fixed in the reactor body to prevent the gas-liquid mixture produced by the reaction from entering the precipitation zone, and the primary gas seal is located below the primary three-phase separator.

[0008] The three-phase separator also includes a secondary three-phase separator, which is located above the primary three-phase separator, and the secondary three-phase separator is correspondingly provided with a secondary air seal.

[0009] A water outlet weir is arranged on the top of the reactor body, the water outlet weir is connected with the water distribution pipe through a supernatant liquid reflux pipe, and a pressure pump is arranged on the supernatant liquid reflux pipe.

[0010] The gas stirring device comprises a booster fan, which is connected to a gas diffusion mechanism located in the reactor body; the top of the gas-liquid separation tower is connected to the gas inlet of the booster fan through a gas reflux pipe.

[0011] The kitchen waste pretreatment device includes a shell, with an inlet pipe connected to the top of the shell, and a heater, an oil collecting tank, and an oil-isolating baffle are arranged in the shell. The oil collecting tank is located above the heater, and the inlet of the water distribution pipe is located in the shell; the oil-isolating baffle is located on the outlet side of the shell, one end of the oil-isolating baffle is fixed to the top of the shell, and the other end is located above the water distribution pipe; the oil collecting tank discharges the grease through the oil drain pipe.

[0012] Another object of the present invention is to provide a method for preparing a carbon source from kitchen waste with high efficiency fermentation.

[0013] Another technical solution adopted by the present invention is a method for preparing a carbon source from kitchen waste by efficient fermentation, which adopts the above-mentioned equipment for preparing a carbon source from kitchen waste by efficient fermentation, comprising:

[0014] The pre-crushed kitchen waste enters the shell and is stratified under the action of the heater. The upper layer of grease enters the oil collecting tank and is discharged through the oil drain pipe; the kitchen waste liquid in the lower layer is injected into the bottom of the reactor body, and the gas stirring device blows out gas to fully mix the kitchen waste liquid and the fermentation liquid. The fermented kitchen waste is separated from the insoluble matter by the primary three-phase separator in turn, and the supernatant flows out from the top of the reactor body; the gas blown out by the gas stirring device is collected by the primary three-phase separator and enters the gas-liquid separation tower to complete the separation of the fermentation liquid and the gas. The fermentation liquid enters the bottom of the reactor body through the central reflux pipe under the action of gravity, and the gas flows back to the gas inlet of the gas stirring device; part of the supernatant flows back to the bottom of the reactor body.

[0015] The kitchen waste dosing ratio of the fermentation reactor is 5-10% of its effective volume; the height-to-diameter ratio of the reactor body is 4-6, the level I reaction zone is below the first-stage three-phase separator, the level II reaction zone is between the first-stage three-phase separator and the second-stage three-phase separator, and the sedimentation zone is above the second-stage three-phase separator, and the volume ratio of the three is 55:30:15.

[0016] The gas of the gas stirring device is N2, and the gas stirring intensity is 20~100L / m 3 .

[0017] The flow rate of the gas-liquid mixture in the riser of the primary three-phase separator and the secondary three-phase separator is 0.6-1.2 m / s.

[0018] The beneficial effects of the present invention are as follows: the kitchen waste efficient fermentation carbon source preparation equipment of the present invention, the kitchen waste pretreatment device simultaneously realizes the isolation and heating of kitchen waste grease, providing basic conditions for subsequent efficient fermentation; the solid concentration of kitchen waste entering the reaction device is adjusted by reflux of the supernatant, and the rising flow rate is controlled to make the mud and water fully contact to ensure the fermentation effect; the violent disturbance in the reactor is achieved by pneumatic internal circulation stirring, and a good mass transfer effect is obtained, which can effectively improve the efficiency of kitchen waste fermentation and acid production. The kitchen waste efficient fermentation carbon source preparation method of the present invention can hydrolyze and acidify organic matter in kitchen waste to form a fermentation liquid rich in volatile fatty acids, which can be used as a very effective external carbon source for sewage biological treatment units, and applied to the sewage treatment field to achieve industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the kitchen waste efficient fermentation carbon source preparation equipment of the present invention.

[0020] In the figure, 1. reactor body, 2. water distribution pipe, 3. central reflux pipe, 4. primary air seal, 5. primary three-phase separator, 6. secondary air seal, 7. secondary three-phase separator, 8. outlet weir, 9. gas-liquid separation tower, 10. supernatant reflux pipe, 11. booster pump, 12. gas reflux pipe, 13. booster fan, 14. gas diffusion mechanism, 15. sludge discharge pipe, 16. inlet pipe, 17. shell, 18. heat exchange coil, 19. heat medium self-supply pipe, 20. heat medium reflux pipe, 21. oil separator, 22. oil collecting tank, 23. oil drain pipe, 24. diaphragm metering pump. DETAILED DESCRIPTION

[0021] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1

[0023] Kitchen waste efficient fermentation carbon source preparation equipment, such as Figure 1 As shown, it includes a kitchen waste pretreatment device for heating and oil-water separation of pre-crushed kitchen waste, the kitchen waste pretreatment device is connected to a fermentation reactor via a water distribution pipe 2, a diaphragm metering pump 24 is provided on the water distribution pipe 2, the fermentation reactor is provided with a gas stirring device and a three-phase separator from bottom to top, the top of the fermentation reactor is connected to a gas-liquid separation tower 9, and the three-phase separator is connected to the gas-liquid separation tower 9.

[0024] The fermentation reactor includes a reactor body 1, and the three-phase separator includes a primary three-phase separator 5. The lifting pipe of the primary three-phase separator 5 is connected to the gas-liquid separation tower 9. The bottom of the gas-liquid separation tower 9 is connected to a central reflux pipe 3, which extends into the reactor body 1, and the outlet is located between the water distribution pipe 2 and the gas stirring device; a primary gas seal 4 is fixed in the reactor body 1 to prevent the gas-liquid mixture produced by the reaction from entering the precipitation area, and the primary gas seal 4 is located below the inlet of the primary three-phase separator 5. The three-phase separator also includes a secondary three-phase separator 7, which is located above the primary three-phase separator 5, and a secondary gas seal 6 is correspondingly arranged below the inlet of the secondary three-phase separator 7. Both the primary three-phase separator 5 and the secondary three-phase separator 7 are conical structures.

[0025] In this embodiment, the interior of the reactor body 1 is divided into three spaces: upper, middle and lower. The upper space is the sedimentation zone, the middle space is the stage II reaction zone, and the lower space is the stage I reaction zone. The first-level three-phase separator 5 is located in the stage II reaction zone, and the second-level three-phase separator 7 is located in the sedimentation zone.

[0026] A water outlet weir 8 is arranged on the top of the reactor body 1, and the water outlet weir 8 is connected to the water distribution pipe 2 through a supernatant return pipe 10. A booster pump 11 is arranged on the supernatant return pipe 10, and the supernatant return pipe 10 is connected to the outlet side of the diaphragm metering pump 24 of the water distribution pipe 2. In this embodiment, the booster pump 11 adopts a variable frequency pipeline pump, the reflux volume is adjusted between 50% and 300%, and the pump head is not more than 10m. A sludge discharge pipe 15 is arranged at the bottom of the reactor body 1.

[0027] The gas stirring device includes a booster fan 13, which is connected to a gas diffusion mechanism 14, and the gas diffusion mechanism 14 is located in the reactor body 1. Furthermore, the gas diffusion mechanism 14 includes a water outlet pipe, on which a nozzle is provided; the gas outlet at the top of the gas-liquid separation tower 9 is connected to the gas inlet of the booster fan 13 through a gas reflux pipe 12, which serves as the gas source of the booster fan 13. The gas loss of the booster fan 13 is supplemented by an external gas source. In this embodiment, the booster fan 13 adopts an explosion-proof motor, the air volume is 10-20% of the water intake, and the wind pressure is the water outlet pipe elevation plus 2 meters of water head.

[0028] In this embodiment, the kitchen waste pretreatment device includes a shell 17, an inlet pipe 16 is connected to the top of the shell 17, a heater, an oil collecting tank 22, and an oil-isolating baffle 21 are arranged in the shell 17, the oil collecting tank 22 is located above the heater and close to the top of the shell 17, and the inlet of the water distribution pipe 2 is located in the shell 17; the oil-isolating baffle 21 is located at the outlet side of the shell 17, one end of the oil-isolating baffle 21 is fixed to the top of the shell 17, and the other end is located above the water distribution pipe 2, which is used to prevent the oil layer from entering the water distribution pipe 2; the oil collecting tank 22 discharges the grease through the oil drain pipe 23. Specifically, the heater includes a heat exchange coil 18, and the heat medium inlet and outlet of the heat exchange coil 18 are respectively connected to the heat medium self-supply pipe 19 and the heat medium return pipe 20.

[0029] Example 2

[0030] The method for preparing a carbon source from kitchen waste with high efficiency fermentation, using the above-mentioned equipment for preparing a carbon source from kitchen waste with high efficiency fermentation, comprises the following steps:

[0031] The pre-crushed food waste enters the shell 17, and is separated into layers by the action of the heater. The upper layer of fat enters the oil collecting tank 22 and is discharged through the oil drain pipe 23. The diaphragm metering pump 24 quantitatively extracts the food waste liquid from the lower layer and injects it into the bottom of the reactor body 1. The gas stirring device blows gas to fully mix the food waste liquid with the fermentation liquid in the reactor body 1. The fermented food waste passes through the primary three-phase separator 5 and the secondary three-phase separator 7 in turn to separate the insoluble substances. The supernatant rich in volatile organic acids flows out from the water outlet at the top of the reactor body 1. The gas blown out of the gas stirring device is collected by the primary three-phase separator 5 and the secondary three-phase separator 7, and enters the gas-liquid separation tower 9 to complete the separation of the fermentation liquid and the gas. The fermentation liquid enters the bottom of the reactor body 1 through the central reflux pipe 3 under the action of gravity, and the gas flows back to the gas inlet of the gas stirring device through the gas reflux pipe 12; part of the supernatant enters the supernatant reflux pipe 10 from the top of the reactor body 1 to be collected, and after being pressurized by the pressure pump 11, it is merged into the water distribution pipe 2 to be mixed with the crushed kitchen waste and returned to the first-level reaction zone.

[0032] In this embodiment, the proportion of kitchen waste in the fermentation reactor is 5-10% of its effective volume. The height-to-diameter ratio of the reactor body 1 is 4-6, the first-level three-phase separator 5 is below the first-level reaction zone, the first-level three-phase separator 5 and the second-level three-phase separator 7 are between the second-level reaction zone, and the second-level three-phase separator 7 is above the precipitation zone, and the volume ratio of the three is 55:30:15. The flow rate of the gas-liquid mixture in the lifting pipe of the first-level three-phase separator 5 and the second-level three-phase separator 7 is 0.6-1.2 m / s. When the diameter of the reactor body 1 exceeds 5 m, multiple lifting pipes can be set.

[0033] The gas of the gas stirring device is N2, and the gas stirring intensity is 20~100L / m 3 The effective volume of the gas-liquid separation tower 9 does not exceed the mixed liquid circulation volume of 15min, and the downward flow velocity in the central reflux pipe 3 is 0.8-1.5m / s. When the diameter of the reactor body 1 is large (more than 5m), a water distribution device can be added at the end of the central reflux pipe 3 to ensure that the mixed liquid is evenly dispersed to the bottom of the entire reactor body 1.

[0034] Through the above methods, the kitchen waste efficient fermentation carbon source preparation equipment of the present invention, the kitchen waste pretreatment device simultaneously realizes the isolation and heating of kitchen waste grease, providing basic conditions for subsequent efficient fermentation; the solid concentration of the kitchen waste entering the reaction device is adjusted by reflux of the supernatant, and the rising flow rate is controlled to make the mud and water fully contact to ensure the fermentation effect; a gas stirring device is provided at the bottom of the fermentation reactor to fully stir and mix the kitchen waste with the fermentation liquid in the reactor to improve the fermentation efficiency. The kitchen waste efficient fermentation carbon source preparation method of the present invention can hydrolyze and acidify the organic matter in the kitchen waste to form a fermentation liquid rich in volatile fatty acids, which can be used as a very effective external carbon source for the sewage biological treatment unit to achieve the goal of efficient resource utilization of kitchen waste.

[0035] Example 3

[0036] The total amount of kitchen waste in the canteen of a coal mine industrial site is 1.3m 3 / d, with a water content greater than 55% and a fat content of 3%; crush the kitchen waste and inject it into an effective volume of 1.5m 3 The kitchen waste pretreatment device is used to heat the kitchen waste by supplying hot water at 60°C, and the return water temperature is 45-50°C; the grease in the heated kitchen waste is separated and floats up, enters the oil collecting tank 22 and is then discharged, and the grease content of the treated kitchen waste is as low as less than 0.1%;

[0037] The pre-treated kitchen waste is uniformly fed into the two-stage fermentation reactor by the diaphragm metering pump 24 according to the daily waste output, and the effective volume is set to 15m3 according to the dosing rate of 10%. 3 The food waste reactor; the supernatant return pump flow rate is 3m 3 / h, head 8m; after the supernatant is mixed with the kitchen waste, it is evenly distributed to the bottom of the reactor body 1 through the water distribution pipe 2 at the bottom of the reactor; the two-stage fermentation reactor body 1 has a diameter of 1.5m and a height of 8.2m. The volume ratio of the first-level reaction zone, the second-level reaction zone and the precipitation zone is 55:30:15. A booster fan with a wind pressure of 130kPa is used, with a speed of 20L / m 3 The bottom of the reactor is mixed with pneumatic stirring intensity of ·min. The flow rates of the gas-liquid mixture in the riser of the primary three-phase separator 5 and the secondary three-phase separator 7 are 0.8m / s and 0.5m / s respectively. The effective volume of the gas-liquid separation tower is 1.2m 3 The downward flow velocity in the central return pipe 3 is 0.7 m / s.

[0038] After fermentation in the first and second reaction zones, the organic matter in the kitchen waste is hydrolyzed and acidified to form a fermentation broth rich in volatile fatty acids. The volatile fatty acids in the fermentation broth were tested many times, and the content ranged from 518 to 1279 mg / L. It is a very effective external carbon source for sewage biological treatment units, and provides a new way for the resource utilization of kitchen waste.

Claims

1. Equipment for preparing carbon source from kitchen waste with high efficiency fermentation, characterized in that: It comprises a kitchen waste pretreatment device for heating and oil-water separation of pre-crushed kitchen waste, the kitchen waste pretreatment device being connected to a fermentation reactor via a water distribution pipe (2), the fermentation reactor being provided with a gas stirring device and a three-phase separator from bottom to top, the top of the fermentation reactor being connected to a gas-liquid separation tower (9), the three-phase separator being connected to the gas-liquid separation tower (9); The fermentation reactor comprises a reactor body (1), the three-phase separator comprises a primary three-phase separator (5), the primary three-phase separator (5) is connected to a gas-liquid separation tower (9), a central reflux pipe (3) is connected to the bottom of the gas-liquid separation tower (9), the central reflux pipe (3) extends into the reactor body (1), and the outlet is located between the water distribution pipe (2) and the gas stirring device; a primary gas seal (4) is fixed in the reactor body (1) for preventing the gas-liquid mixture generated by the reaction from entering the precipitation zone, and the primary gas seal (4) is located below the primary three-phase separator (5); A water outlet weir (8) is provided at the top of the reactor body (1); the water outlet weir (8) is connected to the water distribution pipe (2) via a supernatant liquid return pipe (10); a pressure pump (11) is provided on the supernatant liquid return pipe (10); The three-phase separator further comprises a secondary three-phase separator (7), wherein the secondary three-phase separator (7) is located above the primary three-phase separator (5), and the secondary three-phase separator (7) is correspondingly provided with a secondary gas seal (6).

2. The kitchen waste efficient fermentation carbon source preparation equipment according to claim 1, characterized in that: The gas stirring device comprises a booster fan (13), the booster fan (13) is connected to a gas diffusion mechanism (14), and the gas diffusion mechanism (14) is located in the reactor body (1); the top of the gas-liquid separation tower (9) is connected to the gas inlet of the booster fan (13) through a gas reflux pipe (12).

3. The kitchen waste efficient fermentation carbon source preparation equipment according to claim 1, characterized in that: The kitchen waste pretreatment device comprises a shell (17), the upper part of which is connected to an inlet pipe (16), the shell (17) being provided with a heater, an oil collecting tank (22), and an oil separation baffle (21), the oil collecting tank (22) being located above the heater, and the inlet of the water distribution pipe (2) being located in the shell (17); the oil separation baffle (21) being located at the outlet side of the shell (17), one end of the oil separation baffle (21) being fixed to the top of the shell (17), and the other end being located above the water distribution pipe (2); the oil collecting tank (22) discharges grease through an oil discharge pipe (23).

4. A method for preparing a carbon source from kitchen waste by efficient fermentation, using the equipment for preparing a carbon source from kitchen waste by efficient fermentation according to claim 3, characterized in that: include: The pre-crushed food waste enters the shell (17) and is separated into layers by the action of the heater. The grease in the upper layer enters the oil collecting tank (22) and is discharged through the oil drain pipe (23). The food waste liquid in the lower layer is injected into the bottom of the reactor body (1). The gas stirring device blows out gas to fully mix the food waste liquid and the fermentation liquid. The fermented food waste passes through the primary three-phase separator (5) in turn to separate the insoluble matter, and the supernatant flows out from the top of the reactor body (1). The gas blown out by the gas stirring device is collected by the primary three-phase separator (5) and enters the gas-liquid separation tower (9) to complete the separation of the fermentation liquid and the gas. The fermentation liquid enters the bottom of the reactor body (1) through the central reflux pipe (3) under the action of gravity, and the gas flows back to the gas inlet of the gas stirring device. Part of the supernatant flows back to the bottom of the reactor body (1). The food waste dosage ratio of the fermentation reactor is 5-10% of its effective volume; the height-to-diameter ratio of the reactor body (1) is 4-6; the first-level three-phase separator (5) is located below the first-level three-phase separator (5); the second-level reaction zone is located between the first-level three-phase separator (5) and the second-level three-phase separator (7); and the precipitation zone is located above the second-level three-phase separator (7); and the volume ratio of the three is 55:30:15; The gas used in the gas stirring device is N2, and the gas stirring intensity is 20-100 L / m 3 ; The flow rate of the gas-liquid mixture in the riser pipe of the first-stage three-phase separator (5) and the second-stage three-phase separator (7) is 0.6-1.2 m / s.

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