In-situ biofermentation apparatus based on electro-methanation

Abstract

This invention discloses an in-situ bio-fermentation device based on electro-methane conversion, belonging to the technical field of bio-fermentation. It includes a fermenter equipped with a feed pipe, an air inlet pipe, and an air outlet pipe. An enrichment culture chamber is located within the fermenter, with the feed pipe extending into it. The enrichment culture chamber provides growth sites for hydrogenophilic bacteria. A gas diffuser is located at the bottom of the enrichment culture chamber and is connected to the air inlet pipe. A hydrogen generator is connected to the air inlet pipe, and a gas circulation device is connected to the air outlet pipe. The gas circulation device includes a gas collection bag and an air pump. One end of the gas collection bag is connected to the air outlet pipe, and the other end is connected to the air inlet pipe via the air pump. This invention can improve the methane yield in anaerobic fermentation processes.

Description

Technical Field

[0001] This utility model relates to the technical field of bio-fermentation, and in particular to an in-situ bio-fermentation device based on electro-methane conversion. Background Technology

[0002] Against the backdrop of my country's biogas industry development, improving the efficiency and methane yield of power-to-gas (EPG) technology and achieving its commercialization can bring significant economic, ecological, and social benefits. High-purity biogas can serve as a clean energy source, reducing carbon emissions and promoting energy structure optimization; increasing methane yield can lower production costs and drive the development of the biogas industry. Domestic EPG technology started late and has not yet been commercialized.

[0003] In the process of anaerobic fermentation to produce biogas, there is a problem of low methane yield, mainly due to insufficient activity of hydrogen-producing methanogens. Simultaneously, low hydrogen gas-liquid mass transfer efficiency affects the methane yield per unit volume. Traditional microporous aeration methods are insufficient to meet the requirements for efficient hydrogen mass transfer, resulting in limited biogas purification and an inability to achieve the desired methane concentration. Utility Model Content

[0004] This invention addresses the shortcomings of existing technologies by providing an in-situ bio-fermentation device based on electro-methane conversion, thereby improving the methane yield during anaerobic fermentation.

[0005] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: An in-situ bio-fermentation device based on electro-methane conversion includes a fermenter, which is equipped with a feed pipe, an air inlet pipe, and an air outlet pipe. An enrichment culture chamber is located inside the fermenter, with the feed pipe extending into the chamber. The enrichment culture chamber provides growth sites for hydrogenophilic bacteria. A gas diffuser is located at the bottom of the enrichment culture chamber and is connected to the air inlet pipe. A hydrogen generator is connected to the air inlet pipe, and a gas circulation device is connected to the air outlet pipe. The gas circulation device includes a gas collection bag and a gas pump. One end of the gas collection bag is connected to the air outlet pipe, and the other end is connected to the air inlet pipe via the gas pump.

[0006] By adopting the above technical solution, the feed pipe is used to input fermentation raw materials. The feed pipe extends into the enrichment culture chamber rich in hydrogen-loving bacteria, forming a liquid seal to ensure an anaerobic environment. The gas inlet pipe is connected to a hydrogen generator, which produces hydrogen gas by electrolyzing water (the electrolyte is an alkaline potassium hydroxide solution). The gas production rate, time, and speed can be manually set on the control panel. Outside of the set time, the system enters a sleep mode to save power. The gas diffuser adopts a porous structure, which can evenly disperse hydrogen gas in the fermentation broth, increasing the contact opportunity between hydrogen gas and hydrogen-loving bacteria. The gas inlet pipe and the hydrogen generator are also connected to a gas circulation device. The system uses a valve adjustment switch, near which a gas sensor is installed. An electrical signal is connected to a gas detection device to check if the hydrogen generator is operating normally. The outlet pipe connects to a gas collection bag, which collects the gas escaping from the fermentation broth for subsequent gas recycling. After hydrogen supply is complete, the gas is circulated at a specific rate to ensure hydrogen utilization and produce biogas with a high methane content. This device can improve methane yield during anaerobic fermentation, bringing the power-to-gas technology closer to commercial application standards. It improves energy conversion efficiency while reducing environmental impact, thus promoting the development of the biogas industry.

[0007] Furthermore, the enrichment culture chamber is located at the bottom of the fermenter, and the enrichment culture chamber is a cylindrical mesh structure connected to the inner wall of the fermenter; a water baffle is provided at the top of the enrichment culture chamber, and a stirrer is provided inside the fermenter. The stirrer and the feed pipe both extend into the interior of the enrichment culture chamber through the water baffle, and the gas diffuser is connected to the bottom of the enrichment culture chamber.

[0008] By adopting the above technical solution, an independent enrichment culture chamber is set at the bottom of the fermenter. The chamber wall of the enrichment culture chamber has a mesh structure, which provides more growth sites for hydrogenophilic bacteria. The stirrer is used to uniformly inoculate the sample and mix the fermentation broth with hydrogen gas.

[0009] Furthermore, the enrichment culture chamber is provided with a bacterial sampling port on its exterior.

[0010] By adopting the above technical solution, a separate microbial sampling port is provided on the outer wall of the enrichment culture chamber, which is close to the outer wall of the enrichment culture chamber and leads directly to the outside of the fermentation tank. This allows for the acquisition of fermentation broth rich in microbial strains, enabling microbial testing and facilitating the identification of fermentation problems and monitoring of the fermentation process.

[0011] Furthermore, the interior of the fermenter is filled with activated carbon packing material, which is located at the top of the enrichment culture chamber.

[0012] By adopting the above technical solution, the upper part of the enrichment culture chamber is filled with activated carbon packing. The sprayed fermentation broth seeps down from the activated carbon packing and forms a flowing liquid film on the surface of the packing and in the pores inside the packing. Hydrogen gas comes into full contact with the liquid film during its ascent. The fermentation broth and the hydrogen gas moving from bottom to top travel face to face and mix thoroughly, promoting gas-liquid mass transfer.

[0013] Furthermore, a spray head is provided at the top of the fermentation tank, and the spray head is connected to a liquid pump through a pipe. The liquid pump is connected to the bottom of the fermentation tank through a pipe. The air inlet pipe is located at the bottom of the fermentation tank, and the air outlet pipe is located at the top of the fermentation tank.

[0014] By adopting the above technical solution, the liquid pump (with a small-hole filter screen) can extract the fermentation broth and deliver it to the spray head. That is, the liquid pump can transport the fermentation broth from the bottom to the top of the fermentation tank for spraying. The spray head sprays the fermentation broth evenly onto the activated carbon packing in the form of fine droplets. At the same time, the fermentation broth has secondary contact with the air above the activated carbon. The fermentation broth moves from top to bottom, and the gas moves from bottom to top. The fermentation broth and gas move towards each other, resulting in a larger contact area and more thorough contact, which improves the gas-liquid mass transfer efficiency and the utilization rate of hydrogen.

[0015] Furthermore, the outer wall of the fermenter is provided with a jacket, and a heating and cooling coil is wound in the interlayer between the jacket and the outer wall of the fermenter. The heating and cooling coil is provided with a water inlet and a water outlet, and a temperature sensor is connected between the water outlet and the interlayer.

[0016] By adopting the above technical solution, the temperature inside the fermenter can be controlled by circulating heat medium (water). The system is equipped with an inlet and an outlet for heat medium renewal. The temperature control system is connected to a temperature sensor, which monitors the temperature inside the fermenter in real time and feeds the signal back to the temperature control system so as to adjust the heating or cooling power in a timely manner, so that the temperature inside the fermenter is maintained at the set optimal growth and reaction temperature of 37°C for hydrogenophilic bacteria.

[0017] Furthermore, the fermenter is equipped with a dissolved hydrogen detector and a pH meter, both of which extend into the enrichment culture chamber.

[0018] By adopting the above technical solutions, the pH meter can monitor the pH of the fermentation broth in real time. Hydrogenophilic bacteria are most sensitive to pH, and pH has the greatest impact on the total gas production and methane generation efficiency among all conditions. The dissolved hydrogen detector is used to detect whether the hydrogen generator is working properly, and the gas production efficiency of the hydrogen generator can be adjusted according to the dissolved hydrogen content in the fermentation broth.

[0019] Furthermore, the gas collection bag is connected to a gas detection device, which is a gas sensor.

[0020] By adopting the above technical solution, the gas detection device is used to monitor the gas composition and display the methane and carbon dioxide in the gas bag on the display screen.

[0021] Furthermore, the gas collection bag is connected to a gas collection device, which includes a gas collection tank.

[0022] By adopting the above technical solution, when the gas detection device detects that the methane content reaches the preset value, the valve is automatically opened by the signal sensor to pump the gas collected in the gas collection bag into the gas collection tank for collection.

[0023] Furthermore, a detection port is provided at the lower part of the enrichment culture chamber, and a discharge port is provided at the bottom of the fermenter.

[0024] By adopting the above technical solution, the detection port is used for small-volume discharge to detect the biochemical properties of the fermentation liquid, and the discharge port is used for corresponding large-volume discharge after daily feeding to maintain a constant volume of fermentation liquid in the tank.

[0025] In summary, compared with the prior art, the beneficial effects of the above technical solution are: (1) This invention can domesticate and enrich highly efficient hydrogen-loving methanogenic bacteria: By adjusting the reaction conditions, the total solids (TS) of the fermentation broth (6-8%), the reaction temperature (37℃), and the reaction pH (7-8), hydrogen-loving bacteria are enriched under hydrogen purging conditions. After the hydrogen-loving bacteria are confirmed to be the dominant species, the fermentation of the device can proceed normally and efficiently. If the growth effect of the inoculum is not good, hydrogen-loving bacteria can be enriched by purging hydrogen using this device. After the bacterial strain test and the gas production component test are qualified, the device can still operate normally.

[0026] (2) The gas supply system designed in this utility model improves the gas-liquid mass transfer efficiency of hydrogen: by setting up a gas circulation device, spray head and activated carbon packing, the size of hydrogen bubbles can be effectively minimized, the contact time between hydrogen and fermentation liquid can be extended, the number of contact times can be increased, and the utilization rate of hydrogen can be improved. Gas circulation is carried out by a vacuum pump, and the circulation rate is controlled at about 500 mL / min to ensure the homogeneous distribution of hydrogen in the reaction system.

[0027] (3) The in-situ biological fermentation device of this utility model does not transfer the fermentation liquid or separate the strains. The microorganisms grow, reproduce and carry out metabolic activities directly in the environment where the raw materials are located, and realize the transformation of substances. The fermentation process carried out by this device at the original location of the raw materials belongs to the in-situ fermentation of the in-situ reactor, and realizes the combination of the electrolysis water hydrogen production device (hydrogen generator) and the in-situ reactor.

[0028] (4) The device of this utility model can convert intermittent wind power, photovoltaic power and other surplus electricity into methane, thus solving the problem of peak shaving in the power grid. At the same time, methane can be stored and transported through existing natural gas infrastructure, with a storage period of up to several months, far exceeding electrochemical energy storage, and can achieve long-term energy storage.

[0029] (5) With the help of the device of this utility model, wind power / photovoltaic, electrolytic cell and bioreactor can be integrated in industrial parks to realize the "green electricity-green hydrogen-green methane" closed loop and reduce energy consumption. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0031] Explanation of reference numerals in the attached diagram: 1. Gas collection bag; 2. Gas detection device; 3. Water inlet; 4. Activated carbon packing; 5. Microbial sampling port; 6. Air pump; 7. Detection port; 8. Hydrogen generator; 9. Discharge port; 10. Gas diffuser; 11. Water outlet; 12. Stirrer; 13. Enrichment culture chamber; 14. Heating and cooling coil; 15. Temperature sensor; 16. Liquid pump; 17. Spray head; 18. Feed pipe; 19. pH meter; 20. Dissolved hydrogen detector; 21. Air inlet pipe; 22. Air outlet pipe. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1 The principles and features of this utility model are described, and the examples given are only used to explain this utility model and are not intended to limit the scope of this utility model.

[0033] This utility model discloses an in-situ bio-fermentation device based on electro-converted methane.

[0034] Reference Figure 1 An in-situ biogas fermentation device based on electro-methane conversion includes a fermenter. The fermenter has a cylindrical design and is made of corrosion-resistant stainless steel or plexiglass to ensure stable operation in a long-term biogas fermentation environment. The top of the fermenter is equipped with a feed pipe 18 and an exhaust pipe 22 with valves, and the bottom of the fermenter is equipped with an exhaust pipe 21 with valves.

[0035] The fermenter contains an enrichment culture chamber 13 located at the bottom. The feed pipe 18 is used to add fermentation raw materials, such as cow manure (TS) added daily to supplement nutrients. The feed pipe 18 extends into the enrichment culture chamber 13, forming a liquid seal to ensure an anaerobic environment. The enrichment culture chamber 13 has a cylindrical mesh structure connected to the inner wall of the fermenter. An independent enrichment culture chamber 13 is located at the bottom of the fermenter, with its walls also made of mesh, such as wire mesh, to provide more growth sites for hydrogenophilic bacteria.

[0036] The air intake pipe 21 is connected to a hydrogen generator 8. The hydrogen generator 8 produces hydrogen by electrolyzing water (the electrolyte is an alkaline potassium hydroxide solution). The gas production volume, gas production time, and gas production rate can be manually set on the control panel. Outside of the set time, it will enter sleep mode to save power.

[0037] A gas diffuser 10 is fixedly installed at the bottom of the enrichment culture chamber 13, and the gas diffuser 10 is connected to the air inlet pipe 21. The gas diffuser 10 has a porous structure, which can evenly disperse hydrogen in the fermentation broth and increase the contact opportunity between hydrogen and hydrogenophilic bacteria.

[0038] The gas outlet pipe 22 is connected to a gas circulation device, which includes a gas collection bag 1 and a gas pump 6. One end of the gas collection bag 1 is connected to the gas outlet pipe 22, and the other end is connected to the gas inlet pipe 21 via the gas pump 6. The gas inlet pipe 21 and the hydrogen generator 8 are simultaneously connected to the gas circulation device. A gas sensor is installed near the valve, and the electrical signal is connected to the gas detection device 2 to detect whether the hydrogen generator 8 is operating normally. The gas outlet pipe 22 is connected to the gas collection bag 1, which collects the gas escaping from the fermentation liquid for subsequent gas circulation. After the hydrogen supply is completed, the gas is circulated at a specific rate to ensure the utilization rate of hydrogen and obtain biogas with a high methane content.

[0039] The gas collection bag 1 is connected to a gas detection device 2, which is a gas sensor. The gas detection device 2 is used to monitor the gas composition and displays the methane and carbon dioxide content in the gas bag on a display screen. The gas collection bag 1 is connected to a gas collection device, which includes a gas collection tank. When the gas detection device 2 detects that the methane content reaches a preset value, a valve is automatically opened via a signal sensor to pump the gas collected in the gas collection bag 1 into the gas collection tank for further collection.

[0040] A water-blocking plate is movably installed on the top of the enrichment culture chamber 13. A stirrer 12 is installed inside the fermenter, and the stirrer 12 can be driven by a motor to achieve the stirring effect. Both the stirrer 12 and the feed pipe 18 extend into the interior of the enrichment culture chamber 13 through the water-blocking plate. The gas diffuser 10 is connected to the bottom of the enrichment culture chamber 13. The stirrer 12 is used to uniformly inoculate the sample and simultaneously mix the fermentation broth with hydrogen gas.

[0041] The enrichment culture chamber 13 is provided with a microbial sampling port 5 on its exterior. The microbial sampling port 5 is close to the outer wall of the enrichment culture chamber 13 and leads directly to the outside of the fermentation tank, so as to obtain fermentation broth rich in microbial strains, thereby conducting microbial strain detection, which facilitates the investigation of fermentation problems and monitoring of fermentation status.

[0042] The interior of the fermenter is filled with activated carbon packing 4, which is located at the top of the enrichment culture chamber 13. The portion above the enrichment culture chamber 13 is filled with activated carbon packing 4. The sprayed fermentation broth seeps down through the activated carbon packing 4, forming a flowing liquid film on the surface of the packing and in the pores inside the packing. Hydrogen gas comes into full contact with the liquid film as it rises. The fermentation broth and the upward-moving hydrogen gas travel face to face, making full contact and mixing, thus promoting gas-liquid mass transfer.

[0043] The fermenter is equipped with a spray head 17 at the top, which is connected to a liquid pump 16 via a pipe. The liquid pump 16 is connected to the bottom of the fermenter via a pipe. The liquid pump 16 (with a small-hole filter) can extract the fermentation liquid and transport it to the spray head 17. That is, the liquid pump 16 can transport the fermentation liquid at the bottom of the fermenter to the top of the fermenter for spraying. The spray head 17 sprays the fermentation liquid evenly onto the activated carbon packing 4 in the form of fine droplets. At the same time, the fermentation liquid has secondary contact with the air above the activated carbon. The fermentation liquid moves from top to bottom, and the gas moves from bottom to top. The fermentation liquid and gas move towards each other, resulting in a larger contact area and more thorough contact, which improves the gas-liquid mass transfer efficiency and the utilization rate of hydrogen.

[0044] The fermenter is equipped with a dissolved hydrogen detector 20 and a pH meter 19, both of which extend into the enrichment culture chamber 13 for real-time monitoring of the dissolved hydrogen concentration and pH in the reaction solution. Specifically, the pH meter 19 monitors the pH of the fermentation broth in real time. Hydrogenophilic bacteria are most sensitive to pH, and pH has the greatest impact on the total gas production and methane generation efficiency among all conditions. The dissolved hydrogen detector 20 can be a DH200 portable dissolved hydrogen detector. The dissolved hydrogen detector 20 is used to detect whether the hydrogen generator 8 is working properly, and the gas production efficiency of the hydrogen generator 8 can be adjusted according to the dissolved hydrogen content in the fermentation broth.

[0045] The fermenter is fitted with a jacket on its outer wall. A heating and cooling coil 14 is wound around the jacket and the outer wall of the fermenter. The heating and cooling coil 14 has an inlet 3 and an outlet 11. A temperature sensor 15 is connected between the outlet 11 and the jacket. The temperature inside the fermenter is controlled by circulating heat medium (water). The inlet 3 and outlet 11 allow for heat medium replenishment. The temperature control system is connected to the temperature sensor 15, which monitors the temperature inside the fermenter in real time and feeds the signal back to the temperature control system so that the heating or cooling power can be adjusted in a timely manner to maintain the temperature inside the fermenter at the set optimal growth and reaction temperature of 37°C for hydrogenophilic bacteria.

[0046] The enrichment culture chamber 13 has a detection port 7 at its lower part for detecting the biochemical properties of the fermentation broth with a small volume of material. The fermenter has a discharge port 9 at the bottom for discharging a corresponding large volume of material after daily feeding to maintain a constant volume of fermentation broth inside the tank.

[0047] The implementation principle of an in-situ bio-fermentation device based on electro-converted methane according to this embodiment of the present invention is as follows: Phase 1, Start-up: The device is disinfected and sterilized; hydrogenophilic bacteria are inoculated in enrichment culture chamber 13; activated carbon packing 4 is added; fermentation broth and jacketed heat transfer medium are added; then the spray head 17, temperature control system, pH meter 19, and gas detection device 2 are started for initial fermentation, with real-time monitoring of pH, bacterial strain, gas production, and gas composition; 100 mL of prepared cow dung slurry is added daily, and gas production and composition are measured 24 hours after feeding; various characteristic indicators are measured every 2-3 days; every seven days, the slurry in enrichment culture chamber 13 is taken for DNA processing and species analysis. Phase 2, Hydrogenophilic Bacterial Enrichment: This phase is applicable to those who have been inoculated with hydrogenophilic bacteria but have not been able to reach the operating conditions of the device (Phase 3) for a long time; start the hydrogen generator 8 to introduce hydrogen and enrich the hydrogenophilic methanogens contained in the raw material in the enrichment culture chamber 13. The amount of hydrogen introduced gradually increases with the gas production of the device. After the operating conditions of the device are reached, hydrogen is directly introduced to continue to Phase 3. Phase 3, Device Operation: After the hydrogenophilic bacteria become the dominant species and the gas composition stabilizes (oxygen is almost completely consumed and methane content is stable), start the hydrogen generator 8 and introduce hydrogen gas. The hydrogenophilic bacteria will then convert carbon dioxide in the gas composition into methane. After the hydrogen gas introduction is completed, close the hydrogen inlet and use the gas circulation device to circulate the gas. Phase 4, Gas Collection: During Phase 3 operation, after hydrogen is introduced, when the methane content in the gas collection bag exceeds 99.5% during the gas circulation process, the gas circulation device is shut off, the gas in the gas collection bag 1 is pumped into the gas collection tank, and the next hydrogen introduction is carried out at the same time.

[0048] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An in-situ biofermentation apparatus based on electrotransmethanation comprising a fermentation tank, characterized in that: The fermenter is provided with a feed pipe (18), an air inlet pipe (21), and an air outlet pipe (22). The fermenter is provided with an enrichment culture chamber (13). The feed pipe (18) extends into the interior of the enrichment culture chamber (13). The enrichment culture chamber (13) is used to provide growth sites for hydrogenophilic bacteria. The bottom of the enrichment culture chamber (13) is provided with a gas diffuser (10). The gas diffuser (10) is connected to the air inlet pipe (21). The air inlet pipe (21) is connected to a hydrogen generator (8). The air outlet pipe (22) is connected to a gas circulation device. The gas circulation device includes a gas collection bag (1) and a gas pump (6). One end of the gas collection bag (1) is connected to the air outlet pipe (22), and the other end is connected to the air inlet pipe (21) through the gas pump (6).

2. An in-situ biofermentation device based on electro-methanogenesis according to claim 1, characterized in that: The enrichment culture chamber (13) is located at the bottom of the fermenter. The enrichment culture chamber (13) is a cylindrical mesh structure and is connected to the inner wall of the fermenter. A water baffle is provided at the top of the enrichment culture chamber (13). A stirrer (12) is provided inside the fermenter. The stirrer (12) and the feed pipe (18) both extend into the interior of the enrichment culture chamber (13) through the water baffle. The gas diffuser (10) is connected to the bottom of the enrichment culture chamber (13).

3. The in-situ bio-fermentation device based on electro-methane transfer according to claim 2, characterized in that: The enrichment culture chamber (13) is equipped with a bacterial sampling port (5) on its exterior.

4. The in-situ bio-fermentation device based on electro-methane transfer according to claim 1, characterized in that: The interior of the fermenter is filled with activated carbon packing material (4), which is located at the top of the enrichment culture chamber (13).

5. The in-situ bio-fermentation device based on electro-methane transfer according to claim 4, characterized in that: The top of the fermenter is equipped with a spray head (17), which is connected to a liquid pump (16) via a pipe. The liquid pump (16) is connected to the bottom of the fermenter via a pipe. The air inlet pipe (21) is located at the bottom of the fermenter, and the air outlet pipe (22) is located at the top of the fermenter.

6. The in-situ bio-fermentation device based on electro-methane transfer according to claim 1, characterized in that: The outer wall of the fermenter is provided with a jacket, and a heating and cooling coil (14) is wound around the jacket and the outer wall of the fermenter. The heating and cooling coil (14) is provided with an inlet (3) and an outlet (11). A temperature sensor (15) is connected between the outlet (11) and the jacket.

7. An in-situ biofermentation device based on electro-methanogenesis as claimed in claim 1, wherein: The fermenter is equipped with a dissolved hydrogen detector (20) and a pH meter (19), both of which extend into the enrichment culture chamber (13).

8. The in-situ bio-fermentation device based on electro-methane transfer according to claim 1, characterized in that: The gas collection bag (1) is connected to the gas detection device (2).

9. The in-situ bio-fermentation device based on electro-methane transfer according to claim 8, characterized in that: The gas collection bag (1) is connected to a gas collection device.

10. The in-situ bio-fermentation device based on electro-methane transfer according to claim 1, characterized in that: The enrichment culture chamber (13) is provided with a detection port (7) at the lower part, and the fermenter is provided with a discharge port (9) at the bottom.

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