Bioelectrocatalysis biogas upgrading treatment device

Abstract

The utility model discloses a bioelectrocatalysis biogas upgrading treatment device, which relates to the technical field of kitchen garbage treatment devices, and comprises a reaction chamber, two conductive parts and a voltage applying device, a low-oxygen or oxygen-free environment can be kept in the reaction chamber, and a liquid inlet, a liquid outlet, a gas outlet and two fixing ports are arranged on the reaction chamber; the two conductive parts respectively extend into the reaction chamber through the two fixing ports to form two electrodes; and the voltage applying device is arranged outside the reaction chamber and is electrically connected with the two conductive pieces, so that the two electrodes respectively form an anode and a cathode. According to the device, a microbial electrolysis cell and an anaerobic fermentation process are integrated in one set of device, so that the microbial electrolysis cell and the anaerobic fermentation process are highly and effectively integrated, the removal rate of organic matters in kitchen waste is high, the proportion of CH4 in biogas is high, and the occupied space is small.

Description

Technical Field

[0001] The utility model relates to the technical field of kitchen waste treatment devices, in particular to a bio-electrocatalytic biogas upgrading treatment device. Background Art

[0002] Incineration of domestic waste for power generation is the most efficient way to treat domestic waste, which has the functions of reducing, harmless and resource-based treatment. However, 40-50% of domestic waste is food waste, which has the characteristics of high moisture content, high salt content, high organic matter content, and rich nutrient content. Among them, it is not suitable for incineration because of its high moisture content of 70-95%. Food waste is a kind of easily biodegradable organic waste because it is rich in nutrients required by microorganisms. Anaerobic fermentation is an effective means of biomass energy utilization in recent years. This technology produces renewable energy biogas and realizes energy recovery. It is one of the most ideal resource-based means of treating food waste. The main components of biogas produced by anaerobic fermentation are CH4, CO2 and H2S, as well as a small amount of H2, NH3 and CO. The calorific value of CH4 is about 40MJ / m 3 , and biogas contains CO2, which leads to a decrease in energy density (calorific value is about 20MJ / m 3 ) The main methods for removing CO2 from biogas include physical absorption, chemical absorption, membrane separation, pressure swing adsorption, etc. These technologies have defects such as high energy consumption and secondary pollution, which leads to high costs for biogas upgrading and limits the development of this technology.

[0003] Microbial electrochemical systems are an emerging green environmental technology that has developed in recent years. They encompass a wide range of technologies, including microbial fuel cells, microbial electrolysis cells, and biosensors. Microbial electrolysis cells use electricity as an input and microorganisms as catalysts to produce fuels and chemicals. Given the advantages of microbial electrolysis cells and traditional anaerobic fermentation, combining these two approaches for food waste treatment can create a system that occupies a small footprint, consumes minimal energy, and has low operating costs. Utility Model Content

[0004] The purpose of the utility model is to provide a bio-electrocatalytic biogas upgrading and treatment device to solve the problems existing in the above-mentioned prior art, with high wastewater treatment efficiency, low energy consumption, and a high proportion of CH4 in biogas.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] The utility model provides a bio-electrocatalytic biogas upgrading and processing device, comprising:

[0007] A reaction chamber, wherein the reaction chamber can maintain a low oxygen or oxygen-free environment, and the reaction chamber is provided with a liquid inlet and outlet, an air outlet and two fixed ports;

[0008] Two conductive members, the two conductive members respectively extending into the reaction chamber through the two fixing openings to form two electrodes; and

[0009] A voltage applying device is arranged outside the reaction chamber, and the voltage applying device is electrically connected to the two conductive members so that the two electrodes form an anode and a cathode respectively.

[0010] Preferably, the electrode is coated with carbon felt, and the voltage applying device is a potentiostat.

[0011] Preferably, the fixed port and the conductive part are sealed by AB glue, the liquid inlet and outlet are installed with liquid inlet and outlet rubber tubes, the liquid inlet and outlet rubber tubes can be clamped and sealed with water stop clamps, the air outlet is installed with an air outlet rubber tube, and the air outlet rubber tube is connected to an air bag.

[0012] Preferably, the liquid inlet and outlet rubber tube is inserted into the liquid inlet and outlet port, and one end of the liquid inlet and outlet rubber tube extends into the lower middle portion of the reaction chamber.

[0013] Preferably, the liquid inlet and outlet are used for adding the food waste hydrolyzate in batches.

[0014] Preferably, the reaction chamber is placed in a temperature-controlled shaker or a constant temperature incubator; when placed in the constant temperature incubator, it is equipped with a magnetic stirrer, and the stirring rod of the magnetic stirrer is placed in the reaction chamber.

[0015] Preferably, the temperature of the temperature-controllable shaker is set at 38°C and the shaker speed is set at 140 rpm;

[0016] Alternatively, the temperature of the constant temperature incubator is set at 38°C.

[0017] Preferably, the conductive member is a titanium wire with a diameter of 2 mm.

[0018] Preferably, the reaction chamber is cylindrical.

[0019] Compared with the prior art, the utility model has achieved the following technical effects:

[0020] When the device provided by the present invention is used to treat food waste, after the food waste hydrolyzate enters the reaction chamber, CH4 and CO2 will be produced like the normal anaerobic fermentation process. At the same time, organic matter will also be converted into CH4 and CO2 by the electroactive anaerobic fermentation bacteria biofilm attached to the anode and cathode surfaces, and the CO2 produced in the reaction chamber will be converted into CH4. Compared with the traditional anaerobic fermentation method, the use of electroactive anaerobic fermentation bacteria can promote the conversion of more organic matter into CH4 and CO2, thereby realizing the efficient utilization and removal of organic matter; the device can convert the CO2 produced in the reaction chamber into CH4 by setting the anaerobic fermentation bacteria biofilm attached to the anode and cathode surfaces, thereby increasing the proportion of CH4 in biogas.

[0021] Therefore, the device integrates the microbial electrolysis cell and anaerobic fermentation process into one set of devices, achieving a high degree of effective integration of the two, with a high removal rate of organic matter in food waste, a high proportion of CH4 in biogas, and a small space occupation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a structural schematic diagram of the bioelectrocatalytic biogas upgrading and treatment device provided in an embodiment of the utility model.

[0024] Among them, 1-liquid inlet and outlet; 2-air outlet; 3-fixing port; 4-conductive part; 5-voltage applying device; 6-carbon felt; 7-air outlet rubber tube; 8-air bag; 9-reaction chamber. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0027] The utility model provides a bio-electrocatalytic biogas upgrading and processing device, such as Figure 1As shown, it includes: a reaction chamber 9, two conductive members 4 and a voltage applying device 5.

[0028] A low-oxygen or oxygen-free environment can be maintained in the reaction chamber 9, and the reaction chamber 9 is provided with a liquid inlet and outlet 1, an air outlet 2 and two fixed ports 3; the liquid inlet and outlet 1 is used to introduce the food waste hydrolyzate into the reaction chamber 9, and to extract the muddy, liquid or colloidal reaction products in the reaction chamber 9 to achieve mud discharge and sampling.

[0029] Two conductive members 4 extend into the reaction chamber 9 through the two fixing openings 3 to form two electrodes. The conductive members 4 can be in the form of wires, rods, etc., which is not limited in this embodiment, as long as they can form conductive electrodes.

[0030] The voltage applying device 5 is disposed outside the reaction chamber 9 . The voltage applying device 5 is electrically connected to the two conductive members 4 so that the two electrodes form an anode and a cathode, respectively.

[0031] When the device provided by the present invention is used to treat food waste, after the food waste hydrolyzate enters the reaction chamber 9, CH4 and CO2 will be produced like the normal anaerobic fermentation process. At the same time, organic matter will also be converted into CH4 and CO2 by the electroactive anaerobic fermentation bacteria biofilm attached to the anode and cathode surfaces, and the CO2 produced in the reaction chamber 9 will be converted into CH4. Compared with the traditional anaerobic fermentation method, the use of electroactive anaerobic fermentation bacteria can promote the conversion of more organic matter into CH4 and CO2, thereby achieving efficient utilization and removal of organic matter; the device can convert the CO2 produced in the reaction chamber 9 into CH4 by setting up anaerobic fermentation bacteria biofilm attached to the anode and cathode surfaces, thereby increasing the proportion of CH4 in biogas.

[0032] Therefore, the device integrates the microbial electrolysis cell and anaerobic fermentation process into one set of devices, achieving a high degree of effective integration of the two, with a high removal rate of organic matter in food waste, a high proportion of CH4 in biogas, and a small space occupation.

[0033] Considering that metal electrode surfaces are typically smooth, making them less conducive to the attachment of anaerobic fermentation biofilms, in some embodiments, the electrodes are coated with carbon felt 6, specifically porous carbon felt, to overcome this drawback. Under an applied voltage, carbon felt 6 functions as an anode and a cathode. The surface of carbon felt 6 exhibits excellent adsorption properties, and an electroactive anaerobic fermentation biofilm gradually forms on the surface. This biofilm on the surface of carbon felt 6 participates in the conversion of organic matter into CH4 and CO2. It also converts CO2 generated by anaerobic fermentation sludge within reaction chamber 9 into CH4 under the action of an applied voltage.

[0034] The conversion mentioned here is the same as existing anaerobic digestion technology, meaning that the methane production process conforms to the three-stage, four-group theory. However, after coupling the microbial electrolysis cell with anaerobic digestion technology, other pathways for CH4 production may exist. Under the action of an applied voltage, direct interspecies electron transfer between anaerobic fermentation bacteria and CO2-reducing methanogens may occur. This means that the fermentation bacteria directly transfer the protons and electrons produced by decomposing organic matter to the CO2-reducing methanogens, reducing CO2 to CH4 (Equation 1). Alternatively, hydrogen-producing bacteria on the cathode surface reduce the transferred protons to H2 (Equation 2), which is then used by the CO2-reducing methanogens to reduce CO2 to CH4 (Equation 3). Alternatively, electrons on the cathode surface are directly used by the CO2-reducing methanogens to reduce CO2 to CH4 (Equation 4).

[0035] CO2+8H + +8e - →CH4+2H2O (Formula 1)

[0036] 2H + +2e - →H2 (Formula 2)

[0037] CO2+4H2→CH4+H2O (Formula 3)

[0038] CO2+4H + +4e - →CH4+2H2O (Formula 4)

[0039] In some embodiments, the fixed port 3 and the conductive part 4 are sealed by AB glue, and the liquid inlet and outlet ports 1 are equipped with liquid inlet and outlet rubber tubes, which can be clamped and sealed with water stop clamps to maintain the anaerobic environment in the reaction chamber 9. The air outlet 2 is equipped with an air outlet rubber tube 7, and the air outlet rubber tube 7 is connected to an air bag 8, which is used to collect biogas generated by anaerobic fermentation sludge.

[0040] In some embodiments, the voltage applying device 5 is a potentiostat or any other instrument that can apply voltage to two electrodes and make the two electrodes form a cathode and an anode, respectively.

[0041] In some embodiments, the liquid inlet and outlet rubber tube is installed in the liquid inlet and outlet port 1, and one end of the liquid inlet and outlet rubber tube extends into the middle and lower part of the reaction chamber 9 to facilitate the extraction of muddy, liquid or gel-like reaction products at the bottom of the reaction chamber 9.

[0042] In some embodiments, the liquid inlet and outlet 1 is used for adding the food waste hydrolyzate in batches.

[0043] Specifically, the startup process is carried out under sequencing batch operation conditions. Anaerobic fermentation sludge and food waste hydrolyzate are added to the reaction chamber 9 in a sequencing batch manner. At the same time, the voltage applied by the potentiostat should be gradually increased from a weak voltage. The voltage increase should increase when the COD removal rate, ammonia nitrogen concentration, and biogas composition detected in the reaction chamber 9 are stable. Because when these data are detected to be stable, it is proved that microorganisms that can adapt to the voltage conditions have been selected and corresponding electrical resistance genes have been produced. Therefore, they can adapt to a stronger voltage environment more quickly. If the voltage is increased when it is not stable, the microorganisms that are gradually adapting to the voltage increase will die because they cannot adapt to the change in environment due to the voltage increase again. Therefore, it will take longer to adapt to the voltage increase and the reactor will take longer to stabilize.

[0044] In some embodiments, the reaction chamber 9 is placed in a temperature-controlled shaker or a constant temperature incubator. When placed in the constant temperature incubator, a magnetic stirrer is provided, and the stirring bar of the magnetic stirrer is placed in the reaction chamber.

[0045] Specifically, when placed on a temperature-controlled shaker, the temperature of the temperature-controlled shaker is set at 38° C. and the shaker speed is set at 140 rpm;

[0046] When placed in a constant temperature incubator, the temperature is set at 38°C.

[0047] In some embodiments, the conductive member 4 is preferably a titanium wire, specifically a titanium wire with a diameter of 2 mm. Titanium wire can be used for a long time and has little toxicity to microorganisms.

[0048] If iron wire is used, it will be corroded and fall into the solution during long-term operation, which will prevent the formation of a loop in the reactor. Therefore, the iron wire needs to be replaced frequently. When the iron wire is replaced, the reactor will be in an aerobic environment, which is toxic to anaerobic microorganisms. In addition, copper wire, platinum wire, silver wire, and gold wire can also be selected, but copper wire has the same problem as iron wire, that is, it will be corroded, and copper wire will gradually precipitate copper ions, which are toxic to microorganisms. Therefore, copper wire was not selected; as for other platinum wire, silver wire, and gold wire, they all have the problem of high prices and are therefore not considered.

[0049] In some embodiments, the reaction chamber 9 is cylindrical.

[0050] The wastewater treatment process of the bio-electrocatalytic biogas upgrading treatment device provided in the present application is as follows: the food waste hydrolyzate enters from the liquid inlet and outlet 1, and the organic matter in the food waste hydrolyzate is converted into CH4 and CO2 after being treated by anaerobic fermentation sludge and the electroactive anaerobic fermentation bacteria biofilm attached to the surface of the carbon felt 6. At the same time, the electroactive anaerobic fermentation bacteria biofilm will reduce CO2 to CH4, and the gas generated in the reaction chamber 9 will enter the air bag 8 through the air outlet 2, and the final treated liquid will be discharged from the liquid inlet and outlet 1.

[0051] Application Effect

[0052] The results of using the bio-electrocatalytic biogas upgrading and treatment device of this embodiment to treat food waste hydrolyzate are as follows:

[0053] (1) The bio-electrocatalytic biogas upgrading treatment device of this embodiment is used to treat the influent organic load of 8kg / (m 3 d) The kitchen waste hydrolyzate has a COD>190,000 mg / L and an applied potential of 0.25 V. The COD removal rate is 94.3-99.3%, and the biogas production is 3.03-3.78 L. The biogas composition is CH4 64-68% and CO2 26-28%.

[0054] The bioelectrocatalytic biogas upgrading treatment device of this embodiment controls the effluent COD below 10,000 mg / L, the biogas production is above 3 L, the proportion of methane in the biogas is above 64%, it has a simple structure, low energy consumption, strong impact load resistance, high treatment efficiency, and a high degree of biogas upgrading.

[0055] (2) The bio-electrocatalytic biogas upgrading treatment device of this embodiment is used to treat the influent organic load of 8kg / (m 3 d) The kitchen waste hydrolyzate has a COD of >220,000 mg / L and an applied potential of 0.5 V. The COD removal rate is 94.8-98.4%, and the biogas production is 3.23-3.93 L. The biogas composition is 62.7-67.42% CH4 and 30.8-33.7% CO2.

[0056] The bioelectrocatalytic biogas upgrading treatment device of this embodiment controls the effluent COD below 11000 mg / L, the biogas production is above 3.2 L, the proportion of methane in the biogas is above 62.7%, it has a simple structure, low energy consumption, strong impact load resistance, high treatment efficiency, and a high degree of biogas upgrading.

[0057] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A bioelectrocatalytic biogas upgrading and treatment device, characterized by: include: A reaction chamber, wherein the reaction chamber can maintain a low oxygen or oxygen-free environment, and the reaction chamber is provided with a liquid inlet and outlet, an air outlet and two fixed ports; Two conductive members, the two conductive members respectively extending into the reaction chamber through the two fixing openings to form two electrodes; as well as A voltage applying device is arranged outside the reaction chamber, and the voltage applying device is electrically connected to the two conductive members so that the two electrodes form an anode and a cathode respectively.

2. The bioelectrocatalytic biogas upgrading and treatment device according to claim 1, characterized in that: The electrodes are coated with carbon felt, and the voltage applying device is a potentiostat.

3. The bioelectrocatalytic biogas upgrading and treatment device according to claim 1, characterized in that: The fixing port and the conductive part are sealed by AB glue, the liquid inlet and outlet are installed with liquid inlet and outlet rubber tubes, and the liquid inlet and outlet rubber tubes can be clamped and sealed with water stop clamps, and the air outlet is installed with an air outlet rubber tube, and the air outlet rubber tube is connected to an air bag.

4. The bioelectrocatalytic biogas upgrading and treatment device according to claim 3, characterized in that: The liquid inlet and outlet rubber tube is inserted into the liquid inlet and outlet port, and one end of the liquid inlet and outlet rubber tube extends into the middle and lower part of the reaction chamber.

5. The bioelectrocatalytic biogas upgrading and treatment device according to claim 1, characterized in that: The liquid inlet and outlet are used for adding the kitchen waste hydrolyzate in batches.

6. The bioelectrocatalytic biogas upgrading and treatment device according to claim 1, characterized in that: The reaction chamber is placed in a temperature-controllable shaker or a constant temperature incubator. When placed in the constant temperature incubator, a magnetic stirrer is provided, and a stirring rod of the magnetic stirrer is placed in the reaction chamber.

7. The bioelectrocatalytic biogas upgrading and treatment device according to claim 6, characterized in that: The temperature of the temperature-controlled shaker was set at 38°C and the shaker speed was set at 140 rpm; Alternatively, the temperature of the constant temperature incubator is set at 38°C.

8. The bioelectrocatalytic biogas upgrading and treatment device according to claim 1, characterized in that: The conductive member is a titanium wire with a diameter of 2 mm.

9. The bioelectrocatalytic biogas upgrading and treatment device according to claim 1, characterized in that: The reaction chamber is cylindrical.

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