Kitchen waste anaerobic treatment composite reactor

Abstract

The utility model discloses a kitchen waste anaerobic treatment composite reactor. The composite reactor comprises a reaction tank and a gas-liquid separation tank; a sieve mesh type water distributor is arranged in the reaction tank, a material filter is arranged above the sieve mesh type water distributor, and a slurry inlet communicated with the inner side and the outer side of the reaction tank is formed in the lower side of the sieve mesh type water distributor; a three-phase separator I is arranged above the material filter and is communicated with the gas-liquid separation tank; the gas-liquid separation tank is connected with an internal circulation downcomer, and the lower end of the internal circulation downcomer extends into the reaction tank and extends to the lower side of the sieve pore type water distributor. The reactor disclosed by the utility model has the characteristics of simple structure, suitability for kitchen waste with high suspended solid content, continuous production, flexibility and controllability, can effectively separate supernate wastewater and anaerobic flora sludge and respectively extract the supernate wastewater and the anaerobic flora sludge without external force, additional regulators and additional construction of matched flora culture facilities and solid-liquid separation facilities, and is suitable for industrial production. And residual oil can be effectively removed, and the COD removal rate is stabilized to be 96% or above.

Description

Technical Field

[0001] The utility model relates to a device for treating kitchen waste, in particular to a composite reactor for anaerobic treatment of kitchen waste. Background Art

[0002] Food waste possesses both resource and waste properties. Its primary components include organic matter such as starch, plant fiber, animal protein, and fat. Its high water content, organic matter content, oil content, and salt content make it a breeding ground for bacteria, impacting environmental hygiene. However, the large amount of perishable organic matter in food waste is considered a resource-based waste and is easily degradable. Lightweighting and anaerobic energy conversion of food waste are effective approaches to achieving energy regeneration and socioeconomic benefits, and have become a hot topic in current environmental research.

[0003] At the end of the 20th century, technicians transplanted the anaerobic fermentation biogas production technology used in sewage treatment to food waste treatment. The principle of this technology is that organic matter is fermented and degraded by anaerobic bacteria to produce biogas, and the resulting biogas residue is used as organic fertilizer. Today, more than 95% of projects use anaerobic digestion technology, and the anaerobic treatment equipment put into operation mostly uses two-stage stirred tank fully mixed anaerobic reactors. However, the shortcomings of stirred tank fully mixed anaerobic reactors are:

[0004] (1) It needs to provide power, which results in high operating costs and high energy consumption;

[0005] (2) Only intermittent production is possible, resulting in poor processing capacity;

[0006] (3) The force retention time and the solid retention time are the same, so a supporting solid-liquid separation facility must be built separately;

[0007] (4) The sludge retention time is equal to the hydraulic retention time. Anaerobic bacterial sludge cannot be retained in the reactor, and supporting bacterial culture facilities must be set up separately;

[0008] (5) The anaerobic bacteria cannot accumulate in a sufficient concentration in the stirred tank fully mixed anaerobic reactor, resulting in a long start-up cycle and low efficiency. The degradation rate of organic matter is usually only 65%-75%; the biogas production per ton of garbage is only about 80 cubic meters;

[0009] (6) Methanogens are very sensitive to pH values. Anaerobic fermentation bacteria are most suitable for pH values of 7-8. Each time the food waste is restarted, a large amount of organic acid will be produced in the initial stage of fermentation, causing the pH value of the material to drop below 5, thereby inhibiting the digestion and fermentation process. Alkaline agents need to be added to neutralize it.

[0010] (7) The grease in food waste has a great impact on anaerobic reaction, increasing the difficulty of subsequent water treatment; although the system's previous process has been equipped with a device for extracting grease, the extraction rate generally does not exceed 90%; the stirred tank fully mixed anaerobic reactor cannot achieve further separation of grease.

[0011] In view of the shortcomings of existing technologies, it is necessary to develop a high-efficiency anaerobic treatment reactor for food waste. Utility Model Content

[0012] To address the aforementioned technical issues, the present invention provides a composite reactor for the anaerobic treatment of food waste. This reactor features a simple structure, is suitable for food waste with high suspended solids content, allows for continuous production, and is flexible and controllable. It effectively separates and extracts supernatant wastewater and anaerobic bacterial sludge, eliminating the need for external forces, the addition of additional regulators, or the construction of supporting bacterial culture and solid-liquid separation facilities. It effectively removes residual oil and maintains a stable COD removal rate of over 96%.

[0013] The technical solution of this utility model:

[0014] A composite reactor for anaerobic treatment of kitchen waste, comprising a reaction tank and a gas-liquid separation tank;

[0015] A mesh-type water distributor is provided on the lower side of the reaction tank, a filter is provided above the mesh-type water distributor, and a slurry inlet for connecting the inside and outside of the reaction tank is provided on the lower side of the mesh-type water distributor; a three-phase separator is provided above the filter, and the three-phase separator is connected to the gas-liquid separation tank via a collecting pipe;

[0016] The gas-liquid separation tank is connected to an internal circulation downcomer, the lower end of which penetrates into the reaction tank and extends to the lower side of the sieve-type water distributor.

[0017] Preferably, in the aforementioned composite reactor for anaerobic treatment of food waste, the reaction tank is located below the gas-liquid separation tank, the upper end of the internal circulation downcomer is connected to the bottom of the gas-liquid separation tank, and the lower end of the internal circulation downcomer extends vertically downward to the interior of the reaction tank.

[0018] Preferably, in the aforementioned composite reactor for anaerobic treatment of food waste, a second three-phase separator is provided above the first three-phase separator, and the second three-phase separator is connected to the gas-liquid separation tank via a second collecting pipe.

[0019] Preferably, in the aforementioned composite reactor for anaerobic treatment of food waste, the three-phase separator 1 and the three-phase separator 2 have the same structure, consisting of a plurality of transversely arranged inverted V-shaped grid grooves, and adjacent inverted V-shaped grid grooves are staggered up and down.

[0020] Preferably, in the aforementioned composite reactor for anaerobic treatment of food waste, the bottom of the reaction tank is provided with a conical bottom, and the bottom of the conical bottom is provided with a sludge outlet.

[0021] Preferably, in the aforementioned composite reactor for anaerobic treatment of food waste, a stepped head is provided on the top of the reaction tank, a solid-liquid separation port is provided between the stepped head and the reaction tank, an overflow chamber is provided outside the solid-liquid separation port, and an overflow pipe is connected to the overflow chamber.

[0022] Preferably, in the aforementioned composite reactor for anaerobic treatment of food waste, the top of the reaction tank and the stepped head are connected to the gas-liquid separation tank via a collecting pipe three.

[0023] Preferably, in the aforementioned composite reactor for anaerobic treatment of food waste, the top of the stepped head is connected to a floating oil extraction port.

[0024] Preferably, in the aforementioned composite reactor for anaerobic treatment of food waste, the gas-liquid separation tank is connected to a biogas extraction outlet.

[0025] Beneficial effects of the utility model:

[0026] 1. The reasonable internal structure design of the utility model enables continuous processing of food waste, with a short debugging period and a short startup period, generally about two weeks; and stable operation, good impact load resistance, high volume load and low investment cost.

[0027] 2. The utility model has a large processing capacity. By separating the solid retention time and the hydraulic retention time, the sludge in the sludge expansion bed area above the filter is completely fluidized, which can maintain a large amount of activated sludge retention and a sufficiently long sludge age. The bacterial community is stable and the sludge activity is much higher than that of traditional reactors. The utility model can not only retain a large amount of sludge but also fully mix and contact the wastewater and activated sludge to achieve truly high efficiency, and is a high-load system.

[0028] 3. The utility model does not need to supplement pH regulating drugs. When the tank body maintains a large volume, the internal circulation reflux liquid and the slurry are fully mixed and blended below the sieve-type water distributor. The harmful substances in the original slurry are fully diluted, which greatly reduces the degree of harm and saves a considerable amount of alkali investment costs. This solution not only saves alkali consumption and avoids the increase of salt concentration, but also helps to maintain better activity of anaerobic bacteria and avoid salt poisoning. In addition, since the amount of alkali added is reduced and more methane is produced, the subsequent wastewater treatment costs are further reduced.

[0029] 4. Compared with the existing fully mixed reactor, the reactor of the utility model can separate sludge and sewage more effectively, has a stable water output effect, and the water volume and water quality are uniform and stable, and reduces the cost of adding flocculants and other chemicals for subsequent sludge dehydration.

[0030] 5. The internal circulation structure of the utility model utilizes the expansion of biogas to do work, realizing the internal circulation reflux of a large amount of mixed liquid without the need for external power, strengthening the mass transfer process, greatly improving the removal efficiency of organic matter, and without the need for external power, which is more energy-saving.

[0031] 6. The utility model can effectively separate residual grease. If the oil is not removed, it will affect the subsequent anaerobic ammonia oxidation treatment effect; and the reactor of the utility model also increases the grease recovery rate in kitchen waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Attachment Figure 1 It is a structural schematic diagram of the reactor of the present utility model;

[0033] Attachment Figure 2 This is a schematic structural diagram of the three-phase separator in the reactor of the present invention.

[0034] Explanation of the reference numerals: 1-reaction tank, 2-gas-liquid separation tank, 3-sieve-type water distributor, 4-filter, 5-slurry inlet, 6-three-phase separator one, 7-collecting pipe one, 8-collecting pipe three, 9-floating oil production outlet, 10-biogas production outlet, 11-internal circulation downcomer, 12-conical bottom, 13-sludge outlet, 14-three-phase separator two, 15-collecting pipe two, 16-stepped head, 17-solid-liquid separation port, 18-overflow chamber, 19-overflow pipe, 20-inverted V-shaped grid groove. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to the embodiments, but they are not intended to limit the present invention.

[0036] Embodiments of the present utility model

[0037] A composite reactor for anaerobic treatment of kitchen waste, as shown in the attached Figure 1-2 As shown, it includes two parts, a reaction tank 1 and a gas-liquid separation tank 2, wherein the reaction tank 1 is a circular tank body with a height-to-diameter ratio of 5-8:1, and the reaction tank 1 is installed on a skirt; a sieve-type water distributor 3 is provided on the lower side of the reaction tank 1, a filter 4 is provided above the sieve-type water distributor 3, and a slurry inlet 5 connecting the inside and outside of the reaction tank 1 is provided on the lower side of the sieve-type water distributor 3; a three-phase separator 6 is provided above the filter 4, and the three-phase separator 6 is connected to the gas-liquid separation tank 2 through a collecting pipe 7; an internal circulation downcomer 11 is connected to the gas-liquid separation tank 2, and the lower end of the internal circulation downcomer 11 penetrates into the reaction tank 1 and extends to the lower side of the sieve-type water distributor 3.

[0038] The working process includes the following steps:

[0039] S1. The kitchen waste slurry is pumped into the reaction tank 1 from the slurry inlet 5 at the bottom of the reaction tank 1;

[0040] S2. The slurry is evenly distributed through the mesh water distributor 3 below the reaction tank 1 and flows upward along the interior of the reaction tank 1;

[0041] S3. Under the filtration of the filter 4 above the mesh-type water distributor 3, large floating particles are blocked and retained, forming a large floating bed on the lower side of the filter 4. At this time, the filler in the filter 4 acts as a microbial carrier, and anaerobic bacteria attach and grow inside the filter 4, forming a biofilm. The biofilm and filler together form a fixed bed. The floating slurry undergoes the first stage of anaerobic degradation in the filter 4. This stage of degradation utilizes hydrolytic and acid-producing bacteria to hydrolyze insoluble organic matter into soluble organic matter and decompose macromolecules into small molecules. Microorganisms absorb organic matter. Only soluble small molecules can directly enter microbial cells, while insoluble macromolecules must first be broken down by extracellular enzymes before entering the microorganisms and participating in metabolic processes. This biological selection process provides a longer decomposition reaction time for large organic particles, eliminating a key link in the microbial metabolic pathway. This will undoubtedly accelerate the degradation rate of organic matter in subsequent anaerobic units, thereby increasing the microbial contact area and improving the efficiency of anaerobic treatment. This method significantly improves the methane production efficiency. The sludge bed area only accounts for 30% of the digester volume on average, but 80-90% of organic matter is degraded here.

[0042] S4. The small solid particles and anhydrous matter passing through filter 4 flow further upward, forming a sludge expansion bed above, where COD degradation continues. The COD volumetric load at this stage is very high, and most of the COD is degraded here, producing a large amount of biogas. The expansion work performed by the large amount of biogas bubbles causes the biogas, sludge, and water mixture to be collected in three-phase separator 6 and then fed into gas-liquid separation tank 2 through collecting pipe 7.

[0043] S5. After the sewage is discharged, it further reaches the top of the reaction tank 1 for solid-liquid separation.

[0044] S6. The mud-water mixture entering the gas-liquid separation tank 2 flows into the bottom of the reaction tank 1 through the internal circulation downcomer 11, mixes with the slurry of food waste pumped in through the slurry inlet 5, and repeats steps S1-S5; and the biogas is extracted from the gas-liquid separation tank 2.

[0045] Preferred embodiments include the following Figure 1-2 As shown, the reaction tank 1 is located below the gas-liquid separation tank 2 , the upper end of the internal circulation downcomer 11 is connected to the bottom of the gas-liquid separation tank 2 , and the lower end of the internal circulation downcomer 11 extends vertically downward to the interior of the reaction tank 1 .

[0046] The mud-water mixture in the gas-liquid separation tank 2 of this embodiment can fall down under its own gravity and flow into the reaction tank 1 without the need for external power, which is more energy-efficient.

[0047] Preferred embodiments include the following Figure 1-2 As shown, a three-phase separator 2 14 is provided above the three-phase separator 1 6 , and the three-phase separator 2 14 is connected to the gas-liquid separation tank 2 via a collecting pipe 2 15 .

[0048] In this embodiment, the sewage passing through the lower three-phase separator 1 6 further moves upward and the remaining COD is degraded in the upper layer. The small amount of biogas generated by the degradation in this stage is collected by the three-phase separator 2 14 and sent to the gas-liquid separation tank 2 through the collecting pipe 2 15.

[0049] Preferred embodiments include the following Figure 1-2 As shown, the three-phase separator 1 6 and the three-phase separator 2 14 have the same structure, consisting of a plurality of transversely arranged inverted V-shaped grid slots 20, and adjacent inverted V-shaped grid slots 20 are staggered in vertical arrangement.

[0050] The three-phase separator in this embodiment is an angle steel trough with a downward opening, a grille hole is provided on the angle steel trough, and the upper and lower layers of angle steel troughs are arranged alternately; each angle steel trough is fixedly connected to the inner wall of the reaction tank 1; the upper part of each angle steel trough is connected to the collecting pipe.

[0051] Preferred embodiments include the following Figure 1-2 As shown, the bottom of the reaction tank 1 is provided with a conical bottom 12 , and the bottom of the conical bottom 12 is provided with a sludge outlet 13 , which is used to collect and discharge the sludge at the bottom.

[0052] Preferred embodiments include the following Figure 1-2 As shown, a stepped head 16 is provided on the top of the reaction tank 1 , a solid-liquid separation port 17 is provided between the stepped head 16 and the reaction tank 1 , an overflow chamber 18 is provided outside the solid-liquid separation port 17 , and an overflow pipe 19 is connected to the overflow chamber 18 .

[0053] The stepped head 16 of this embodiment is a common overflow-type stepped head. Solid-liquid separation is completed under the action of the stepped head 16 , and the supernatant flows into the overflow chamber 18 through the solid-liquid separation port 17 and is then collected through the overflow pipe 19 .

[0054] Preferred embodiments include the following Figure 1-2 As shown, the top of the reaction tank 1 and the stepped head 16 are connected to the gas-liquid separation tank 2 via the collecting pipe 3 8 . The collecting pipe 3 8 can collect the biogas at the top and transfer it to the gas-liquid separation tank 2 .

[0055] Preferred embodiments include the following Figure 1-2 As shown, the top of the stepped head 16 is connected to the floating oil production outlet 9.

[0056] In this embodiment, the floating oil reaches the top of the stepped head 16 and is produced through the floating oil production port 9 .

[0057] Preferred embodiments include the following Figure 1-2 As shown, the gas-liquid separation tank 2 is connected to a biogas production outlet 10, which is used to discharge biogas.

[0058] The above is only a preferred specific implementation method of the present invention, but the scope of protection of the present invention is not limited to this. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention within the technical scope disclosed by the present invention, and they should be covered by the scope of protection of the present invention.

Claims

1. A composite reactor for anaerobic treatment of kitchen waste, characterized by: It comprises two parts: a reaction tank (1) and a gas-liquid separation tank (2); A mesh-type water distributor (3) is provided on the lower side of the reaction tank (1), a filter (4) is provided above the mesh-type water distributor (3), and a slurry inlet (5) is provided on the lower side of the mesh-type water distributor (3) for conducting the inside and outside of the reaction tank (1); a three-phase separator (6) is provided above the filter (4), and the three-phase separator (6) is conducted to the gas-liquid separation tank (2) via a collecting pipe (7); The gas-liquid separation tank (2) is connected to an internal circulation downcomer (11), and the lower end of the internal circulation downcomer (11) penetrates into the reaction tank (1) and extends to the lower side of the sieve-type water distributor (3).

2. The composite reactor for anaerobic treatment of food waste according to claim 1, characterized in that: The reaction tank (1) is located below the gas-liquid separation tank (2), the upper end of the internal circulation downcomer (11) is connected to the bottom of the gas-liquid separation tank (2), and the lower end of the internal circulation downcomer (11) extends vertically downward to the interior of the reaction tank (1).

3. The composite reactor for anaerobic treatment of food waste according to claim 1, characterized in that: A three-phase separator 2 (14) is provided above the three-phase separator 1 (6), and the three-phase separator 2 (14) is connected to the gas-liquid separation tank (2) via a collecting pipe 2 (15).

4. The composite reactor for anaerobic treatment of food waste according to claim 3, characterized in that: The three-phase separator 1 (6) and the three-phase separator 2 (14) have the same structure, consisting of a plurality of transversely arranged inverted V-shaped grid grooves (20), and adjacent inverted V-shaped grid grooves (20) are staggered in vertical arrangement.

5. The composite reactor for anaerobic treatment of food waste according to claim 1, characterized in that: The bottom of the reaction tank (1) is provided with a conical bottom (12), and the bottom of the conical bottom (12) is provided with a sludge outlet (13).

6. The composite reactor for anaerobic treatment of food waste according to claim 1, characterized in that: The top of the reaction tank (1) is provided with a stepped head (16), a solid-liquid separation port (17) is provided between the stepped head (16) and the reaction tank (1), an overflow chamber (18) is provided outside the solid-liquid separation port (17), and an overflow pipe (19) is connected to the overflow chamber (18).

7. The composite reactor for anaerobic treatment of food waste according to claim 6, characterized in that: The top of the reaction tank (1) and the stepped head (16) are connected to the gas-liquid separation tank (2) via a collecting pipe (8).

8. The composite reactor for anaerobic treatment of food waste according to claim 6, characterized in that: The top of the stepped head (16) is connected to a floating oil production outlet (9).

9. The composite reactor for anaerobic treatment of food waste according to claim 1, characterized in that: The gas-liquid separation tank (2) is connected to a biogas extraction outlet (10).

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