CN114806858A - Device and method for recovering volatile fatty acid in anaerobic fermentation system - Google Patents

Device and method for recovering volatile fatty acid in anaerobic fermentation system Download PDF

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CN114806858A
CN114806858A CN202210577386.7A CN202210577386A CN114806858A CN 114806858 A CN114806858 A CN 114806858A CN 202210577386 A CN202210577386 A CN 202210577386A CN 114806858 A CN114806858 A CN 114806858A
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anaerobic fermentation
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volatile fatty
vfas
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史绪川
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Qingyan Environmental Technology Co ltd
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Abstract

In the technical scheme provided by the application, a pipeline is arranged in the device for recovering volatile fatty acid in the anaerobic fermentation system, the pipe wall of the pipeline is a separation membrane, the middle part of the pipeline is coiled in anaerobic fermentation liquid, and two ends of the pipeline are both communicated with the absorption liquid storage tank; the pipe wall made of the separation membrane material is used as a barrier to separate anaerobic fermentation liquid from absorption liquid in the pipeline, the concentration difference of free VFAs at the inner side and the outer side of the pipe wall is used as a driving force, the free VFAs in the anaerobic fermentation liquid are gasified, enter micropores of the pipe wall from the outer side of the pipe wall through diffusion, and are absorbed by the absorption liquid in the pipeline to generate VFAs acid radical ions after being diffused to the inner side of the pipe wall through the micropores. In this application, store anaerobic fermentation liquid's anaerobic fermentation jar and contain last cavity and lower cavity that sets up from top to bottom, go up and set up the separate layer between cavity and the lower cavity, go up and be separated by the separate layer between cavity and the lower cavity, realize the division of hydrolytic acidification and VFAs separation recovery, alleviate the pollution of solid particle to the barrier film simultaneously.

Description

Device and method for recovering volatile fatty acid in anaerobic fermentation system
Technical Field
The invention belongs to the technical field of separation devices or methods, and particularly relates to a device and a method for recovering volatile fatty acid in an anaerobic fermentation system.
Background
With the continuous improvement of living standards and the comprehensive implementation of garbage classification, the yield of perishable organic garbage represented by kitchen garbage and the like is greatly increased, and huge municipal and environmental pressures have been developed. The anaerobic fermentation technology can realize the harmless treatment and resource utilization of perishable organic garbage, and is considered to be the biomass garbage treatment technology with the widest application and the most promising prospect. The anaerobic fermentation technology can decompose organic matters to generate intermediate products such as volatile fatty acids (abbreviated as VFAs), ammonia nitrogen and the like. The traditional anaerobic fermentation technology can further decompose volatile fatty acid into methane, carbon dioxide and the like, and the carbon in the organic matter is recovered in the form of methane.
And compared with methane, VFAs generated in the anaerobic fermentation process have higher economic value and can be used as a carbon source for sewage plants or further purified into chemical raw materials. VFAs are short-chain volatile fatty acids with 6 carbon atoms or less, and mainly comprise: acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, and the like. However, in the prior art, VFAs produced by anaerobic fermentation are difficult to separate from the fermentation broth. In addition, the high concentration of VFAs in the fermentation liquor can reduce the pH value of the fermentation system and inhibit the continuous acid production reaction. In the prior art, the separation of VFA in fermentation liquor is usually realized by adopting methods such as a distillation method, an ion exchange method and the like. However, these methods are complicated in process and long in flow path, and cannot realize in-situ separation and extraction of VFA from the anaerobic fermentation reactor.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides a device and a method for recovering volatile fatty acid in an anaerobic fermentation system.
The application provides a retrieve device of volatile fatty acid in anaerobic fermentation system, contains:
the anaerobic fermentation tank comprises an upper cavity and a lower cavity which are arranged up and down, a separation layer is arranged between the upper cavity and the lower cavity, and anaerobic fermentation liquid enters the anaerobic fermentation tank from the upper cavity;
an absorption liquid storage tank for storing an absorption liquid;
the pipe wall of the pipeline is a separation membrane, the middle part of the pipeline is coiled in the lower cavity, two ends of the pipeline are both communicated with the absorption liquid storage tank, and the power device is configured to provide power for the absorption liquid to flow into the pipeline from the absorption liquid storage tank and then flow back to the absorption liquid storage tank from the pipeline;
in the anaerobic fermentation process, part of materials in the upper cavity body enter the lower cavity body through the separation layer.
Preferably, the separation layer comprises a filter screen and a support layer, and the support layer is provided with through holes and configured below the filter screen for supporting and fixing the filter screen.
Preferably, the mesh number of the filter screen is 100-500.
Preferably, the absorption liquid is an alkaline absorption liquid.
Preferably, the apparatus for recovering volatile fatty acids in an anaerobic fermentation system further comprises:
the absorption liquid temperature regulating and controlling device is used for regulating the temperature of the absorption liquid in the pipeline of the disc cloth in the lower cavity;
and the control unit is used for controlling the temperature of the absorption liquid regulating and controlling device according to the temperature of the anaerobic fermentation liquid in the anaerobic fermentation tank.
Preferably, the apparatus for recovering volatile fatty acids in an anaerobic fermentation system further comprises:
and the conductivity sensor is arranged in the absorption liquid storage tank and used for detecting the conductivity of the absorption liquid.
The present application also provides a method for recovering volatile fatty acids from an anaerobic fermentation system comprising separating volatile fatty acids from said anaerobic fermentation broth that has been hydrolytically acidified.
Preferably, the volatile fatty acid in the anaerobic fermentation liquid enters the pipeline in a gas form to be combined with the alkaline absorption liquid flowing in the pipeline by conveying the alkaline absorption liquid to the pipeline which is distributed in the anaerobic fermentation liquid, and the pipe wall of the pipeline is a separation membrane.
Preferably, the volatile fatty acids are separated from the anaerobic fermentation broth after filtering out large particle solids in the anaerobic fermentation broth.
Preferably, the conductivity of the alkaline absorption liquid which separates the volatile fatty acid from the anaerobic fermentation liquid is detected, and whether the pipe wall is wetted is judged through the conductivity.
According to the specific embodiment provided by the invention, compared with the prior art, the invention discloses the following technical effects:
in the technical scheme provided by the application, a pipeline is arranged in the device for recovering volatile fatty acid in the anaerobic fermentation system, the pipe wall of the pipeline is a separation membrane, the middle part of the pipeline is coiled in the lower cavity, two ends of the pipeline are both communicated with the absorption liquid storage tank, and a power device is configured to provide power for the absorption liquid to flow into the pipeline from the absorption liquid storage tank and then flow back to the absorption liquid storage tank from the pipeline; the pipe wall made of the separation membrane material is used as a barrier to separate anaerobic fermentation liquor containing Volatile Fatty Acids (VFAs in short) from absorption liquid in the pipe, the concentration difference of free VFAs at the inner side and the outer side of the pipe wall is used as a driving force, the VFAs in the anaerobic fermentation liquor in a free state are gasified, enter micropores of the pipe wall from the outer side of the pipe wall through diffusion, and are rapidly and irreversibly absorbed by the absorption liquid in the pipe after being diffused to the inner side of the pipe wall through the micropores to generate VFAs acid radical ions, so that the VFAs are separated from the anaerobic fermentation liquor. In the application, the anaerobic fermentation tank for storing anaerobic fermentation liquid comprises an upper cavity and a lower cavity which are arranged up and down, a separation layer is arranged between the upper cavity and the lower cavity, and anaerobic fermentation liquid enters the anaerobic fermentation tank from the upper cavity; in the anaerobic fermentation process, part of materials in the upper cavity body enter the lower cavity body through the separation layer. The upper cavity and the lower cavity are separated by a separating layer, so that the division of hydrolytic acidification and VFAs separation and recovery is realized. Hydrolysis reaction and partial acid production reaction are carried out in the upper cavity, and the concentration of solid particles in the anaerobic fermentation liquid is higher; the acid production reaction and the separation and recovery of VFAs are completed in the lower cavity, and the separation and recovery efficiency is high. Furthermore, most solid particles in the anaerobic fermentation liquid are intercepted in the upper cavity, and the concentration of the solid in the lower cavity is low, so that the pollution to the pipe wall made of the separation membrane material can be reduced.
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FIG. 1 is a schematic view of an apparatus for recovering volatile fatty acids in an anaerobic fermentation system, provided in example 1 of the present invention.
Wherein the reference numbers are schematic: the anaerobic fermentation tank comprises an anaerobic fermentation tank 1, an upper cavity 101, a lower cavity 102, a filter screen 201, a supporting layer 202, a pipeline 3, a stirring device 4, an absorption liquid storage tank 5, an upper part 601 of the anaerobic fermentation liquid temperature control device and an upper part 602 of the anaerobic fermentation liquid temperature control device.
Detailed Description
The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
For example, the treatment of perishable organic waste such as municipal solid waste. The organic part of the household garbage accounts for 50% -75%, and the household garbage comprises kitchen garbage, fruit and vegetable garbage, paper, garden waste and the like. The anaerobic digestion technology is adopted to treat the kitchen waste, so that resource utilization can be realized, pollution is reduced, and simultaneously, the methane is produced to be used as renewable energy. Anaerobic digestion of kitchen waste easily causes accumulation of volatile fatty acid, and methanogen activity is inhibited.
This embodiment provides a device for recovering volatile fatty acid in anaerobic fermentation system, which separates volatile fatty acid in the anaerobic fermentation process in the anaerobic fermentation tank 1.
Referring to fig. 1, the apparatus for recovering volatile fatty acids in an anaerobic fermentation system comprises:
the anaerobic fermentation tank 1 comprises an upper cavity 101 and a lower cavity 102 which are arranged up and down, a separation layer is arranged between the upper cavity 101 and the lower cavity 102, and anaerobic fermentation liquid enters the anaerobic fermentation tank 1 from the upper cavity 101; the anaerobic fermentation liquid comprises anaerobic fermentation microorganisms, the anaerobic fermentation tank 1 is provided with a feed inlet and a discharge outlet, and raw materials are continuously supplemented and fermented waste liquid is discharged;
an absorption liquid storage tank 5 for storing an absorption liquid;
the pipeline 3, the pipe wall of the pipeline 3 is a separation membrane, the middle part of the pipeline 3 is coiled in the lower cavity 102, both ends of the pipeline 3 are communicated with the absorption liquid storage tank 5, and the power device is configured to provide power for the absorption liquid to flow into the pipeline 3 from the absorption liquid storage tank 5 and then flow back to the absorption liquid storage tank 5 from the pipeline 3;
during the anaerobic fermentation process, part of the materials in the upper cavity 101 enter the lower cavity 102 through the separation layer.
In the device for recovering Volatile Fatty acid in an anaerobic fermentation system provided in this embodiment, the tube wall of the separation membrane material of the tube 3 serves as a barrier to separate anaerobic fermentation liquid containing Volatile Fatty Acid (VFAs), from absorption liquid in the tube 3, and with the concentration difference of free VFAs at the inner and outer sides of the tube wall as a driving force, the VFAs in the anaerobic fermentation liquid in a free state gasifies, enters the micropores of the tube wall from the outer side of the tube wall through diffusion, and is rapidly and irreversibly absorbed by the absorption liquid in the tube 3 after being diffused to the inner side of the tube wall through the micropores to generate VFAs acid radical ions, thereby separating the VFAs from the anaerobic fermentation liquid.
The absorption liquid in the pipeline 3 and the absorption liquid storage tank 5 is continuously circulated, and in the middle of the pipeline 3 in the anaerobic fermentation tank, the absorption liquid absorbs VFAs and gradually changes into a carboxylate solution (when the absorption liquid is selected from a sodium hydroxide solution, the carboxylate solution comprises sodium acetate, sodium propionate, sodium butyrate, sodium isobutyrate and the like), and the carboxylate solution returns to the absorption liquid storage tank 5.
Because excessive VFAs are removed in time in the anaerobic fermentation tank, the aims of removing the VFAs in the anaerobic fermentation tank and reducing the concentration of the VFAs are fulfilled, the product inhibition effect of the VFAs can be relieved or relieved, the anaerobic fermentation acid production reaction is promoted, and the reaction efficiency of the anaerobic fermentation is improved.
In this embodiment, the anaerobic fermentation tank 1 for storing anaerobic fermentation liquid comprises an upper cavity 101 and a lower cavity 102 which are arranged up and down, a separation layer is arranged between the upper cavity 101 and the lower cavity 102, and solid organic matters such as kitchen waste enter the anaerobic fermentation tank 1 from the upper cavity 101; solid organic matters in the upper cavity 101 are changed into dissolved anaerobic fermentation liquid through hydrolysis reaction, acid production reaction is performed on part of the dissolved anaerobic fermentation liquid to generate VFAs, in the anaerobic fermentation process, the dissolved anaerobic fermentation liquid in the upper cavity 101, including the generated VFAs, enters the lower cavity 102 through the separation layer, and most large particles are trapped in the upper cavity 101. The upper cavity 101 and the lower cavity 102 are separated by a separating layer, so that the division of hydrolytic acidification and VFAs separation and recovery is realized. Hydrolysis reaction is carried out in the upper cavity 101, and the concentration of solids in anaerobic fermentation liquid is higher; the separation and recovery of the VFAs is accomplished in the lower chamber 102 with high efficiency. Furthermore, since most of the large particles in the anaerobic fermentation liquid are trapped in the upper chamber 101, the solid concentration in the lower chamber 102 is low, which reduces the contamination of the tube wall made of the separation membrane.
In a preferred embodiment, the organic load of the anaerobic fermentation tank is 6-10 gVS/(d.L), namely the feeding amount is 60-100 g/(d.L) based on the kitchen waste with VS (total volatile solid) content of 10%.
The material of the separation membrane is preferably hydrophobic material. In this embodiment, the hydrophobic material is not particularly limited, and may be hydrophobic materials known to those skilled in the art, such as Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), or polypropylene (PP). The aperture of the membrane material used by the separation membrane is preferably 0.02-0.4 μm, and more preferably 0.1-0.3 μm. The separation membrane preferably comprises a tubular membrane or hollow fiber membrane filaments. The present invention is not limited to the tubular membrane or the hollow fiber membrane yarn, and a commercially available tubular membrane or hollow fiber membrane yarn made of a hydrophobic material, which is well known to those skilled in the art, may be used, or a tubular membrane or hollow fiber membrane yarn prepared from the hydrophobic material by a method well known to those skilled in the art may be used. VFAs in the anaerobic fermentation liquid pass through the separation membrane in a gas form and are absorbed by absorption liquid circularly flowing in the separation membrane, so that the separation and recovery of the VFAs are realized, and water and soluble components in the anaerobic fermentation liquid cannot penetrate through the hydrophobic separation membrane, so that the extraction selectivity of the VFAs is ensured.
The absorption liquid is alkaline absorption liquid. The initial concentration of the alkaline absorption liquid is preferably 0.2-1 mol/L, and more preferably 0.4-0.8 mol/L. After the alkaline absorption liquid absorbs VFAs, the pH value gradually decreases, and when the pH value of the alkaline absorption liquid decreases to 7.8-8.2, the alkaline absorption liquid needs to be replaced by new alkaline absorption liquid. The circulation flow of the alkaline absorption liquid is preferably matched with the volume of the anaerobic fermentation tank, and particularly when the volume of the anaerobic fermentation tank is 1L, the circulation flow of the alkaline absorption liquid is preferably 10-50 mL/min, and more preferably 20-40 mL/min.
In a preferred embodiment, the separation layer comprises a filter 201 and a support layer 202, and the support layer 202 is provided with through holes and disposed under the filter 201 for supporting and fixing the filter 201. The mesh number of the filter screen 201 is 100-500, and solid particles in the anaerobic fermentation liquid are blocked from passing through the separation layer. The filter screen 201 is made of nylon filter cloth or fabric filter cloth, and the nylon filter cloth can be replaced when the filter screen is blocked by large granular substances. The filter screen preferably comprises 2-4 layers of nylon filter cloth or fabric filter cloth.
In order to ensure the efficient performance of the anaerobic fermentation process, the embodiment of the device for recovering volatile fatty acid in the anaerobic fermentation system further comprises an anaerobic fermentation liquid temperature regulating device. The anaerobic fermentation tank 1 is connected with an anaerobic fermentation liquid temperature regulating device, and the anaerobic fermentation liquid temperature regulating device can be used for carrying out optimal temperature regulation according to the fermentation temperature of anaerobic fermentation. In this embodiment, the anaerobic fermentation liquid temperature control device includes a circulating water bath and a water bath interlayer, the water bath interlayer is disposed on the outer wall of the anaerobic fermentation tank 1, water which flows circularly through the circulating water bath and has a certain temperature is introduced into the water bath interlayer, and the temperature is adjusted according to the fermentation temperature required by anaerobic fermentation. Wherein the temperature of anaerobic fermentation is preferably 25-37 ℃, and more preferably 35 ℃.
The present embodiment also provides an embodiment of the anaerobic fermenter 1: the top of the anaerobic fermentation tank 1 is provided with an upper cover to form a closed environment of the anaerobic fermentation tank 1. In this embodiment, the upper cover is provided with a feeding hole, and the bottom of the upper cavity 101 and the bottom of the lower cavity 102 of the anaerobic fermentation tank 1 are both provided with a discharging hole. Organic solid waste materials to be treated stored in the raw material storage tank enter the anaerobic fermentation tank 1 from the feed inlet, and are treated by anaerobic digestion and VFAs separation recovery, and the obtained fermentation residual liquid is discharged from the discharge outlet. A spacer is arranged between the anaerobic fermentation tank 1 and the upper cover so as to further ensure the tightness of the anaerobic fermentation tank 1.
This embodiment provides an embodiment of the power device, wherein a pump body is arranged on the passage between the absorption liquid storage tank 5 and the pipeline 1, the pump body provides power for absorbing liquid to enter the pipeline 1 from the absorption liquid storage tank 5, and the pump body is preferably a peristaltic pump.
In order to ensure the thorough anaerobic fermentation reaction, in this embodiment, the device for recovering volatile fatty acids in the anaerobic fermentation system is further provided with a stirring device 4, a motor of the stirring device 4 is arranged above the anaerobic fermentation tank 1, a helical blade wheel is respectively arranged in the upper cavity 101 and the lower cavity 102, a wheel shaft of the helical blade wheel is connected with an output shaft of the motor, the anaerobic fermentation liquid in the anaerobic fermentation tank 1 is turned over through the stirring device 4, more VFAs in the upper cavity 101 can be filtered into the lower cavity 102, and more VFAs in the lower cavity 102 can be carried away from the anaerobic fermentation tank 1 by the absorption liquid in the pipeline 3. In a preferred embodiment, the stirring speed of the stirring device is preferably 80-140 rpm.
In a preferred embodiment, the apparatus for recovering volatile fatty acids from an anaerobic fermentation system further comprises: an absorption liquid temperature regulating device for regulating the temperature of the absorption liquid in the pipe 3 wound in the lower chamber 102; and the control unit is used for controlling the temperature of the absorption liquid regulating and controlling device according to the temperature of the anaerobic fermentation liquid in the anaerobic fermentation tank. Too large a temperature difference results in mass transfer of water vapor from the higher vapor pressure side of the two sides of the separation membrane to the lower side, i.e., osmotic distillation occurs. Osmotic distillation occurs and a large amount of water vapor is transferred across the membrane, affecting the efficiency of VFAs mass transfer across the membrane. The temperature linkage control between absorption liquid and the anaerobic fermentation tank is adopted in the embodiment, the temperature difference between the absorption liquid and the anaerobic fermentation tank is controlled in a very small range, and the vapor pressure on two sides of the separation membrane is consistent, so that the occurrence of osmotic distillation is avoided, and the separation efficiency of VFAs is ensured.
In a preferred embodiment, the apparatus for recovering volatile fatty acids from an anaerobic fermentation system further comprises: and the conductivity sensor is arranged in the absorption liquid storage tank 5 and used for detecting the conductivity of the absorption liquid. When the pipe wall of the separation membrane material of the pipeline 1 is wetted, soluble salt in anaerobic fermentation liquid in the lower cavity 102 can enter the pipeline 1 after the separation membrane is wetted, and when absorption liquid containing soluble salt entering the pipeline 1 circulates back to the absorption liquid storage tank 5, the conductivity of liquid in the absorption liquid storage tank can be suddenly increased.
In another embodiment, the device for recovering volatile fatty acid in the anaerobic fermentation system further comprises a balance, the absorption liquid storage tank is placed on the balance, the condition that the separation membrane is penetrated due to the pollution of the separation membrane of the pipeline can be warned through the change of the scale indication, in particular, if the scale indication is reduced, the separation membrane is penetrated, the absorption liquid enters the anaerobic fermentation tank, and a new separation membrane is replaced in time.
Example 2
This example provides a method for recovering volatile fatty acids in an anaerobic fermentation system, which comprises separating volatile fatty acids from the anaerobic fermentation broth subjected to hydrolytic acidification, and the implementation of the method for recovering volatile fatty acids in an anaerobic fermentation system by the apparatus for recovering volatile fatty acids in an anaerobic fermentation system provided in example 1 is one of the preferred modes of this example.
The anaerobic fermentation technology can decompose organic matters to generate intermediate products such as volatile fatty acid, ammonia nitrogen and the like. The traditional anaerobic fermentation technology can further decompose volatile fatty acid into methane, carbon dioxide and the like, and the carbon in the organic matter is recovered in the form of methane.
And compared with methane, VFAs generated in the anaerobic fermentation process have higher economic value and can be used as a carbon source for sewage plants or further purified into chemical raw materials. VFAs are short-chain volatile fatty acids with 6 carbon atoms or less, and mainly comprise: acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, and the like. In the prior art, VFA produced by anaerobic fermentation is difficult to separate from fermentation liquor. In addition, the high concentration of VFAs in the fermentation liquor can reduce the pH value of the fermentation system and inhibit the continuous acid production reaction. In the prior art, the separation of VFA in fermentation liquor is usually realized by adopting methods such as a distillation method, an ion exchange method and the like. However, these methods are complicated and long in flow path, and cannot realize in-situ separation and extraction of VFAs from the anaerobic fermentation reactor.
In this example, unlike the prior art, which separates VFAs from anaerobic fermentation broth and recycles them, the present invention decomposes them into methane and carbon dioxide. The separated VFAs can be used as a carbon source of a sewage plant or further purified into chemical raw materials, so that the anaerobic fermentation process is reduced, and the effective recovery of the VFAs is realized. Specifically, when a sodium hydroxide solution is selected as the alkaline absorption liquid, the alkaline absorption liquid gradually changes into a carboxylate solution (including sodium acetate, sodium propionate, sodium butyrate, sodium isobutyrate and the like) through continuous cyclic absorption of free VFAs, and the high-purity carboxylate can be obtained through concentration and fractional crystallization of the carboxylate solution.
In the method for recovering volatile fatty acid in an anaerobic fermentation system provided in this embodiment, an alkaline absorption liquid is delivered to a pipeline distributed in the anaerobic fermentation liquid, the volatile fatty acid in the anaerobic fermentation liquid enters the pipeline in a gas form to be combined with the alkaline absorption liquid flowing in the pipeline, and a pipe wall of the pipeline is a separation membrane. The inventive concept of this example to separate volatile fatty acids from anaerobic fermentation broth is the same as the device for recovering volatile fatty acids in anaerobic fermentation system described in example 1, and is not described again.
In order to efficiently separate and recover VFAs, the volatile fatty acid is separated from the anaerobic fermentation liquor after solid particles in the anaerobic fermentation liquor are filtered, and meanwhile, the effect of reducing the pollution of the solid particles to the pipe wall made of a separation membrane material is achieved.
The apparatus for recovering volatile fatty acids in an anaerobic fermentation system provided in this embodiment further comprises: and detecting the conductivity of the alkaline absorption liquid with the volatile fatty acid separated from the anaerobic fermentation liquid, and judging whether the pipe wall is complete or not according to the conductivity. When the pipe wall of the pipeline made of the separation membrane material is broken, anaerobic fermentation liquid enters the pipeline, the conductivity of the alkaline absorption liquid is changed after the anaerobic fermentation liquid entering the pipeline circularly flows into the alkaline absorption liquid, and whether the membrane is broken or not is monitored through the conductivity.
In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the devices or elements referred to must have particular orientations, be constructed and operated in particular orientations, and thus, are not to be construed as limiting the present technical solution.
In this disclosure, unless explicitly stated or limited otherwise, the terms "mounted," "connected," and "fixed" are to be construed broadly, e.g., as a fixed connection, a detachable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present technical solution can be understood by those of ordinary skill in the art according to specific situations.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present technology. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.

Claims (10)

1. An apparatus for recovering volatile fatty acids from an anaerobic fermentation system, comprising:
the anaerobic fermentation tank comprises an upper cavity and a lower cavity which are arranged up and down, a separation layer is arranged between the upper cavity and the lower cavity, and anaerobic fermentation liquid enters the anaerobic fermentation tank from the upper cavity;
an absorption liquid storage tank for storing an absorption liquid;
the pipe wall of the pipeline is a separation membrane, the middle part of the pipeline is coiled in the lower cavity, two ends of the pipeline are both communicated with the absorption liquid storage tank, and the power device is configured to provide power for the absorption liquid to flow into the pipeline from the absorption liquid storage tank and then flow back to the absorption liquid storage tank from the pipeline;
in the anaerobic fermentation process, part of materials in the upper cavity body enter the lower cavity body through the separation layer.
2. The apparatus of claim 1, wherein the separation layer comprises a screen and a support layer, the support layer having apertures therethrough and being disposed beneath the screen for supporting and securing the screen.
3. The apparatus as claimed in claim 2, wherein the mesh number of the filter net is 100-500.
4. The apparatus of claim 3, wherein the absorption liquid is an alkaline absorption liquid.
5. The apparatus of any of claims 1 to 4, further comprising:
the absorption liquid temperature regulating and controlling device is used for regulating the temperature of the absorption liquid in the pipeline of the disc cloth in the lower cavity;
and the control unit is used for controlling the temperature of the absorption liquid regulating and controlling device according to the temperature of the anaerobic fermentation liquid in the anaerobic fermentation tank.
6. The apparatus of any of claims 1 to 4, further comprising:
and the conductivity sensor is arranged in the absorption liquid storage tank and used for detecting the conductivity of the absorption liquid.
7. A process for recovering volatile fatty acids from an anaerobic fermentation system comprising separating volatile fatty acids from said anaerobic fermentation broth that has been hydrolytically acidified.
8. The method of claim 7, wherein the volatile fatty acid in the anaerobic fermentation liquid enters the pipeline in a gas form by conveying the alkaline absorption liquid to the pipeline distributed in the anaerobic fermentation liquid, and is combined with the alkaline absorption liquid flowing in the pipeline, and the pipe wall of the pipeline is a separation membrane.
9. The method of claim 8, wherein the volatile fatty acids are separated from the anaerobic fermentation broth after filtering out large particle solids in the broth.
10. The method of claim 8, wherein the conductivity of the alkaline absorption solution from which volatile fatty acids are separated from the anaerobic fermentation broth is measured and the determination of whether the tube wall is wetted is made by the conductivity.
CN202210577386.7A 2022-05-25 2022-05-25 Device and method for recovering volatile fatty acid in anaerobic fermentation system Pending CN114806858A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115420605A (en) * 2022-09-15 2022-12-02 中国石油大学(华东) Experimental device and method for transmitting chloride ions in concrete with temperature difference on two sides

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115420605A (en) * 2022-09-15 2022-12-02 中国石油大学(华东) Experimental device and method for transmitting chloride ions in concrete with temperature difference on two sides

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