Biogas in-situ purification device and method

Abstract

The biogas in-situ purification device comprises an acid production reactor and a methane production reactor, a discharge port is formed in the bottom of the acid production reactor, the methane production reactor is provided with a feed port connected with the discharge port, a first gas outlet is formed in the top of the methane production reactor, and a second gas outlet is formed in the bottom of the methane production reactor. A gas inlet for directly introducing hydrogen or synthesis gas is formed in the bottom of the methanogenesis reactor, and a conductive material inlet is formed in the acid production reactor and / or the methanogenesis reactor. The conductive material inlet is formed in the acidogenic reactor and / or the methanogenic reactor, and the conductive material is introduced into the system, so that on one hand, the conductive material can promote an interspecific direct electron transfer mode among microorganisms, the tolerance of the acidogenic microorganisms to hydrogen is enhanced, and the overall operation stability of the system is enhanced; and on the other hand, the conductive material can promote the formation of granular sludge in the methane production reactor and enhance the symbiotic metabolism and action among microorganisms, so that the conversion rate of carbon dioxide and the purity of methane in the final biogas are improved.

Description

Technical Field

[0001] The invention is used in the field of environmental engineering, and particularly relates to a biogas in-situ purification device and method. Background Art

[0002] Anaerobic digestion is a process that converts organic matter into biogas (mainly methane and carbon dioxide) through the action of microorganisms under oxygen-free conditions. This technology is widely used in sewage treatment, agricultural waste treatment, and biomass energy production. However, the traditional anaerobic digestion process has a slow organic matter conversion rate, and the biogas produced contains a high proportion of carbon dioxide and other impurities, which limits its value for direct use.

[0003] In recent years, hydrogen-assisted in-situ biogas purification technology has gradually attracted attention. This technology increases the proportion of methane in biogas by adding an appropriate amount of hydrogen to the anaerobic digestion system and using microorganisms to convert carbon dioxide into methane. This method reduces additional physical or chemical purification steps and helps improve the overall energy efficiency of the system. However, hydrogen introduction technology also faces challenges, the most important of which is that excessive hydrogen partial pressure will inhibit acid-producing microorganisms, thereby affecting microbial metabolic activity and organic matter conversion efficiency, reducing system operation stability, and may even cause the system to crash. Summary of the invention

[0004] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a biogas in-situ purification device and method.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] In a first aspect, a biogas in-situ purification device comprises an acidogenic reactor and a methanogenic reactor, wherein the acidogenic reactor is provided with a discharge port at the bottom, the methanogenic reactor is provided with a feed port connected to the discharge port, the methanogenic reactor is provided with a first gas outlet at the top, the methanogenic reactor is provided with a gas inlet for directly introducing hydrogen or synthesis gas at the bottom, and the acidogenic reactor and / or the methanogenic reactor is provided with a conductive material inlet.

[0007] In combination with the first aspect, in certain implementations of the first aspect, a reducing gas tank is further included, the reducing gas tank is filled with hydrogen or synthesis gas, the reducing gas tank is connected to the air inlet through a first pipeline, and the first pipeline is provided with a first gas pump.

[0008] In combination with the first aspect and the above-mentioned implementation manner, in some implementation manners of the first aspect, a second gas outlet is provided at the top of the acid-generating reactor, the second gas outlet is connected to a second pipeline, the second pipeline is provided with a gas flow meter, and the second pipeline is connected to the first pipeline through a first three-way valve.

[0009] In combination with the first aspect and the above-mentioned implementations, in certain implementations of the first aspect, anaerobic granular sludge is provided inside the methanogenic reactor, the feed port is arranged at the bottom of the methanogenic reactor, the discharge port is connected to the feed port through a third pipe, and the third pipe is provided with a feeding pump.

[0010] In combination with the first aspect and the above-mentioned implementations, in certain implementations of the first aspect, the acid generating reactor is provided with a feed port, and the in-situ biogas purification device further includes a pretreatment tank, which is used to mix the feed of the acid generating reactor with the conductive material and then input it into the feed port.

[0011] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, a gas reflux port is provided at the bottom of the methanogenic reactor, and the gas reflux port is connected to the first gas outlet through a fourth pipeline, and the fourth pipeline is provided with a second gas pump, and the fourth pipeline is provided with a second three-way valve, and a gas production port is formed through the second three-way valve.

[0012] In combination with the first aspect and the above-mentioned implementations, in certain implementations of the first aspect, a discharge port is provided at the bottom of the methanogenic reactor, and a water outlet is provided at the top of the methanogenic reactor.

[0013] In combination with the above implementations, in certain implementations, a stirrer is provided inside the acid generating reactor, and the acid generating reactor is provided with a sampling port.

[0014] In a second aspect, a method for in-situ purification of biogas is provided, using the in-situ purification device for biogas described in any implementation method of the first aspect, comprising the following steps: material is input into an acidogenic reactor, and a solid-liquid mixture produced by fermentation in the acidogenic reactor enters a methanogenic reactor through a feed inlet, during which hydrogen or synthesis gas is introduced into the methanogenic reactor through an air inlet, and a conductive material is added to the acidogenic reactor and / or the methanogenic reactor through a conductive material inlet, and the gas produced in the methane reactor is discharged through a first air outlet.

[0015] In combination with the second aspect, in certain implementations of the second aspect, the conductive material includes one or more of nano-magnetite, nano-zero-valent iron, activated carbon powder, and magnetic biochar.

[0016] One of the above technical solutions has at least one of the following advantages or beneficial effects:

[0017] 1. A two-phase anaerobic reactor system is used. The raw materials are first fed into the acidogenic reactor for fermentation, and the resulting solid-liquid mixture is then introduced into the methanogenic reactor. This design achieves effective physical isolation of microorganisms of different metabolic types, providing the most suitable growth environment for each microorganism. In addition, by introducing hydrogen or synthesis gas into the methanogenic reactor, the carbon dioxide in the biogas can be converted into methane, thereby solving the theoretical problem of insufficient methane purity caused by high carbon dioxide concentration during the biological conversion of organic matter, and realizing the in-situ purification of biogas.

[0018] 2. In the whole process, conductive materials are introduced into the system. On the one hand, conductive materials can promote the direct electron transfer mode between microorganisms, enhance the tolerance of acid-producing microorganisms to hydrogen, and enhance the overall stability of the system. On the other hand, conductive materials can promote the formation of granular sludge in the methanogenic reactor, enhance the symbiotic metabolism of microorganisms, and improve the conversion rate of carbon dioxide and the purity of methane in biogas.

[0019] 3. Hydrogen is only introduced into the methanogenic reactor rather than the acidogenic reactor, which can avoid direct contact between the acidogenic microorganisms that are most sensitive to hydrogen and hydrogen, further ensuring the stability of the process.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 It is a schematic structural diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0023] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0024] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention.

[0025] In the present invention, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present invention, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0026] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0027] See also Figure 1 The embodiment of the present invention provides an in-situ biogas purification device, including an acidogenic reactor 100 and a methanogenic reactor 200, wherein the acidogenic reactor 100 is provided with a discharge port 101 at the bottom, the methanogenic reactor 200 is provided with a feed port 201 connected to the discharge port 101, the methanogenic reactor 200 is provided with a first gas outlet 202 at the top, and the methanogenic reactor 200 is provided with a gas inlet 203 for directly introducing hydrogen or synthesis gas at the bottom. Synthesis gas is a raw gas with carbon monoxide and hydrogen as the main components and is used as a chemical raw material. The purpose of introducing hydrogen or synthesis gas from the outside is to convert carbon dioxide in the generated biogas into methane and improve the purity of methane in the final product biogas. However, excessive hydrogen partial pressure will inhibit the acidogenic phase microorganisms, thereby affecting the microbial metabolic activity and organic matter conversion efficiency. Based on this, hydrogen or synthesis gas is directly introduced into the methanogenic reactor to avoid the inhibitory effect on the core functional microorganisms in the acidogenic reactor-acidogenic bacteria, and the acidogenic reactor 100 and / or the methanogenic reactor 200 are provided with a conductive material inlet.

[0028] Combination Figure 1, with kitchen waste, excess sludge and food production wastewater as materials, the materials are first input into the acid-producing reactor 100, the solid-liquid mixture produced by fermentation in the acid-producing reactor 100 enters the methanogenic reactor 200 through the feed port 201, and the liquid discharge branch of the acid-producing reactor 100 transports the acidified product to the methanogenic reactor 200, so as to realize further conversion of organic matter in the methanogenic reactor 200, improve the conversion efficiency of organic matter, and react with hydrogen or synthesis gas introduced from the air inlet 203 inside the methanogenic reactor 200, so as to improve the purity of methane in the final product biogas, and realize in-situ purification. Meanwhile, by setting a conductive material inlet in the acid-producing reactor 100 and / or the methanogenic reactor 200, a conductive material can be added to the biogas in-situ purification device, so as to induce the formation of a direct electron transfer mode between microorganisms, and reduce the inhibitory effect of high hydrogen partial pressure on acid-producing microorganisms, so as to enhance the system stability during the process of endogenous hydrogen generation and exogenous hydrogen introduction. In addition, adding solid particles of conductive materials with good conductivity such as nano-magnetite, nano-zero-valent iron, activated carbon, etc. as fillers inside the methanogenic reactor 200 can also promote the formation of granular sludge and significantly improve the biological conversion and hydrogen utilization efficiency in the system.

[0029] In summary, the present invention significantly improves the efficiency of converting organic waste into energy, the purity of biogas and the stability of system operation by introducing solid particles with good electrical conductivity as filling materials, rationally adjusting the position of hydrogen supply points and improving the gas circulation mechanism.

[0030] In addition, by providing a gas inlet 203 for directly introducing hydrogen or synthesis gas at the bottom of the methanogenic reactor 200 instead of directly introducing hydrogen or synthesis gas into the acidogenic reactor 100, the inhibition of acidogenic microorganisms in the acidogenic reactor 100 can be avoided.

[0031] In some embodiments, see Figure 1 The biogas in-situ purification device also includes a reducing gas tank 300, which is filled with hydrogen or synthesis gas. The reducing gas tank 300 is connected to the air inlet 203 through a first pipeline 301. The first pipeline 301 is provided with a first gas pump 302. The first gas pump 302 can adopt a gas peristaltic pump, which can control the reducing gas input into the methanogenic reactor 200.

[0032] In some embodiments, see Figure 1, a second gas outlet 102 is provided on the top of the acid-producing reactor 100, and the second gas outlet 102 is connected to a second pipeline 103. The second pipeline 103 is provided with a gas flow meter 104, and the gas flow meter 104 can monitor the gas flow in real time, which is convenient for regulating the intake amount of downstream hydrogen or synthesis gas. The second pipeline 103 is connected to the first pipeline 301 through a first three-way valve 105. Among them, the gas discharge branch of the acid-producing reactor 100 transports the generated gas to the methanogenic reactor 200, which can effectively reduce the inhibitory effect of the main component hydrogen in the gas on the acid-producing phase microorganisms. At the same time, this connection method can strengthen the coupling of the two phases on the gas product, providing raw materials for subsequent methanogenesis. The gas in the acidogenic reactor 100 is transported to the gas inlet 203 through the second pipeline 103, the first three-way valve 105 and the first pipeline 301 to reach the methanogenic reactor 200. Because the hydrogen / carbon dioxide ratio in the gas coming out of the acidogenic phase reactor is too low, the biogas-methane generated by entering the methanogenic reactor 200 still contains a large amount of unused carbon dioxide, resulting in low methane concentration and calorific value in the biogas. The exogenous addition of hydrogen or synthesis gas can increase the hydrogen / carbon dioxide ratio in the methanogenic reactor 200, strengthen the conversion of carbon dioxide in the methanogenic reactor ((H2+CO2→CH4), and reduce the residual carbon dioxide.

[0033] In some embodiments, see Figure 1 Anaerobic granular sludge 204 is arranged inside the methanogenic reactor 200, a feed port 201 is arranged at the bottom of the methanogenic reactor 200, a discharge port 101 is connected to the feed port 201 through a third pipe 106, and a feed pump 107 is arranged in the third pipe 106. The methanogenic reactor 200 adopts an upflow anaerobic sludge blanket reactor, which can form anaerobic granular sludge 204; the formation of granular sludge can significantly improve the biological conversion rate, load, and carbon dioxide conversion rate and efficiency.

[0034] In some embodiments, see Figure 1 , the acid-producing reactor 100 is provided with a feed port 110, and the biogas in-situ purification device also includes a pretreatment tank 400, which is used to mix the feed of the acid-producing reactor 100 with the conductive material and then input it into the feed port 110. In this embodiment, the conductive material inlet is set in the pretreatment tank 400, so that the conductive material can enter the acid-producing reactor 100 with the feed, and by introducing conductive materials (such as nano magnetite, nano zero-valent iron, activated carbon powder, magnetic biochar) into the reaction system, the metabolic rate of microorganisms is accelerated, thereby improving the organic load and conversion efficiency. More importantly, the rate of conductive materials can induce direct interspecies electron transfer paths in the anaerobic digestion system, improve the tolerance of acid-producing microorganisms to high hydrogen partial pressure, and enhance the stability of system operation.

[0035] In some embodiments, the conductive material includes one or more of nano magnetite, nano zero-valent iron, activated carbon powder, and magnetic biochar. On the one hand, the conductive material can promote the interspecies direct electron transfer mode between microorganisms, enhance the tolerance of acid-producing microorganisms to hydrogen, and enhance the overall stability of the system. On the other hand, the conductive material can promote the formation of granular sludge in the methanogenic reactor, enhance the symbiotic metabolism of microorganisms, and improve the conversion rate of carbon dioxide.

[0036] Among them, see Figure 1 The gas reflux port 205 is provided at the bottom of the methanogenic reactor 200, and the gas reflux port 205 is connected to the first gas outlet 202 through the fourth pipeline 206. The fourth pipeline 206 is provided with a second gas pump 207, and the fourth pipeline 206 is provided with a second three-way valve 208, and a gas production port 209 is formed through the second three-way valve 208. The gas in the methanogenic reactor 200 is partially refluxed through the second three-way valve 208, and enters the methanogenic reactor 200 again to participate in the reaction, which can effectively further improve the purity of methane in the final biogas. The purified biogas can be discharged through the gas production port, and a flow meter can be set at the gas production port to detect the gas production of the biogas.

[0037] In some embodiments, see Figure 1 A discharge port 210 is provided at the bottom of the methanogenic reactor 200, and the methanogenic reactor 200 can discharge solid wastes through the discharge port 210 regularly. A water outlet is provided at the top of the methanogenic reactor 200.

[0038] In the embodiment of the present invention, the design of the upflow anaerobic sludge bed as the methanogenic reactor can promote the formation of a granular sludge structure, which not only strengthens the mutualistic effect between the internal microorganisms, but also improves the resistance to the high hydrogen partial pressure environment and the carbon dioxide conversion rate and efficiency. At the same time, by optimizing the design of the gas circulation path inside the methanogenic reactor, the time for hydrogen to participate in the methane synthesis reaction is increased, ensuring that the methane content in the generated gas reaches a high level.

[0039] In some embodiments, see Figure 1 The acid generating reactor 100 is provided with a sampling port 108 , through which the reaction process and state of the acid generating reactor 100 can be monitored in real time.

[0040] Wherein, in some embodiments, see Figure 1 A stirrer 109 is provided inside the acid generating reactor 100 to increase the reaction rate inside the acid generating reactor 100 .

[0041] The present invention also provides a method for in-situ purification of biogas, which uses the in-situ purification device of biogas in any of the above embodiments, including the following steps: material is input into the acid-producing reactor 100, and the solid-liquid mixture produced by fermentation in the acid-producing reactor 100 enters the methanogenic reactor 200 through the feed port 201, during which hydrogen or synthesis gas is introduced into the methanogenic reactor 200 through the air inlet 203, and conductive material is added to the acid-producing reactor and / or the methanogenic reactor through the conductive material inlet, and the gas produced by the methane reactor 200 is discharged through the first air outlet 202.

[0042] In the description of this specification, the description with reference to the terms "example", "embodiment" or "some embodiments" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0043] Of course, the invention is not limited to the above-mentioned embodiments, and those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the invention, and these equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A biogas in-situ purification device, characterized in that: It comprises an acidogenic reactor and a methanogenic reactor, wherein the acidogenic reactor is provided with a discharge port at the bottom, the methanogenic reactor is provided with a feed port connected to the discharge port, the methanogenic reactor is provided with a first gas outlet at the top, the methanogenic reactor is provided with a gas inlet for directly introducing hydrogen or synthesis gas at the bottom, and the acidogenic reactor and / or the methanogenic reactor is provided with a conductive material inlet.

2. The biogas in-situ purification device according to claim 1, characterized in that: It also includes a reducing gas tank filled with hydrogen or synthesis gas, and the reducing gas tank is connected to the air inlet through a first pipeline, and the first pipeline is provided with a first gas pump.

3. The biogas in-situ purification device according to claim 2, characterized in that: A second gas outlet is provided on the top of the acid generating reactor, the second gas outlet is connected to a second pipeline, a gas flow meter is provided on the second pipeline, and the second pipeline is connected to the first pipeline through a first three-way valve.

4. The biogas in-situ purification device according to claim 1, characterized in that: Anaerobic granular sludge is arranged inside the methanogenic reactor, the feed port is arranged at the bottom of the methanogenic reactor, the discharge port is connected to the feed port through a third pipeline, and the third pipeline is provided with a feeding pump.

5. The biogas in-situ purification device according to claim 1, characterized in that: The acid generating reactor is provided with a feeding port, and the biogas in-situ purification device further comprises a pretreatment tank, which is used to mix the feed of the acid generating reactor with the conductive material and then input the mixed feed into the feeding port.

6. The biogas in-situ purification device according to claim 1, characterized in that: A gas reflux port is provided at the bottom of the methanogenic reactor, and the gas reflux port is connected to the first gas outlet through a fourth pipeline. The fourth pipeline is provided with a second gas pump, and the fourth pipeline is provided with a second three-way valve, and a gas production port is formed through the second three-way valve.

7. The biogas in-situ purification device according to claim 1, characterized in that: A discharge port is provided at the bottom of the methanogenic reactor, and a water outlet is provided at the top of the methanogenic reactor.

8. The biogas in-situ purification device according to claim 1, characterized in that: A stirrer is arranged inside the acid generating reactor, and a sampling port is arranged in the acid generating reactor.

9. A method for in-situ purification of biogas, characterized in that: The biogas in-situ purification device according to any one of claims 1 to 8 comprises the following steps: material is input into an acidogenic reactor, a solid-liquid mixture produced by fermentation in the acidogenic reactor enters a methanogenic reactor through a feed inlet, hydrogen or synthesis gas is introduced into the methanogenic reactor through an air inlet, a conductive material is added to the acidogenic reactor and / or the methanogenic reactor through a conductive material inlet, and gas produced in the methane reactor is discharged through a first air outlet.

10. The biogas in-situ purification method according to claim 9, characterized in that: The conductive material includes one or more of nano magnetite, nano zero-valent iron, activated carbon powder, and magnetic biochar.

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