JP5154771B2 - Biogas generation system and method - Google Patents

Description

  The present invention relates to a biogas generation system and a biogas generation method for treating a biogas obtained by methane fermentation of organic waste and purifying it so as to increase the content of an active component such as a flammable component methane gas component. It is about.

  The biogas obtained by methane fermentation of organic waste mainly contains methane gas and carbon dioxide, and the ratio varies depending on the properties of the organic waste, but usually about 50-60% by volume of methane gas. Carbon dioxide is contained in an amount of about 40 to 50% by volume. In addition, about 0.2% by volume of hydrogen sulfide is contained. Thus, the biogas contains a high concentration of carbon dioxide, which reduces the utility value of biogas as a fuel. For example, when power generation is performed using a gas engine, untreated biogas has a high carbon dioxide content, so the gas engine cannot be driven stably, and there is a problem in terms of reliability. It was. Therefore, in order to perform high-efficiency and high-reliability power generation using biogas as a fuel, it is effective to increase the concentration of methane gas components by reducing and removing carbon dioxide and to increase the calorie of biogas.

  As a carbon dioxide removal method (decarbonation method), in addition to the PSA method using an absorbent, an absorption treatment method in which carbon dioxide is absorbed by the absorbent is generally known. As the absorbent, a liquid absorbent adjusted to basicity or a solid absorbent that selectively adsorbs carbon dioxide is used. These absorption treatment methods are expensive because they require a large amount of absorbent and auxiliary materials, and there is a problem that the equipment is enlarged. The PSA method is also not practical because the equipment cost and operation cost are not low.

  In addition, a method of removing carbon dioxide has been reported that can reduce the amount of liquid used by circulating and reusing the absorbing liquid by using a solvent that can be regenerated by releasing carbon dioxide as the absorbing liquid ( For example, see Patent Document 1). However, in this carbon dioxide removal method, a certain amount of absorption liquid is always required in the removal process, and a vacuum degassing treatment apparatus is separately provided as a process for degassing carbon dioxide from the absorption liquid after absorbing carbon dioxide. Necessary, resulting in complicated equipment and high costs.

  In addition, a purification process that selectively adsorbs and removes carbon dioxide from biogas using a molecular sieve charcoal that selectively adsorbs carbon dioxide and can be regenerated as an absorbent, and a regeneration process that regenerates the molecular sieve charcoal. A methane gas purification method that is carried out mutually has been reported (see, for example, Patent Document 2). However, this refining method requires a separate regeneration step for regenerating the molecular sieving carbon adsorbed with carbon dioxide, which complicates the equipment.

Japanese Patent Laid-Open No. 2003-230810 JP 2001-170695 A

  The present invention has been made in view of such a situation, and an object of the present invention is to increase the content of an effective component such as a methane gas component by removing carbon dioxide in biogas easily and at low cost (purification). It is to provide a biogas generation system and a biogas generation method that can be performed.

  In order to achieve the above object, a biogas generation system according to the first aspect of the present invention includes a fermenter that ferments organic waste to generate biogas, and a fermentation liquid that is partially extracted from the fermenter. The fermentation liquor gas reduction treatment means for reducing the dissolved carbon dioxide gas, and the gas reduction fermentation liquor treated by the fermentation liquor gas reduction treatment means are brought into gas-liquid contact with the biogas so that carbon dioxide in the biogas is obtained. Gas-liquid contact means to be absorbed in the gas-reduced fermentation broth.

  According to the present invention, the dissolved carbon dioxide gas in the fermentation liquor partially taken out from the fermenter is reduced. Then, the “gas-reducing fermentation liquor”, which is a fermentation liquor in which dissolved carbon dioxide is reduced, is brought into gas-liquid contact with the biogas, and the carbon dioxide in the biogas is dissolved in the gas-liquid by the dissolution equilibrium. It is configured to be absorbed in the “liquid”. Therefore, it is possible to remove the carbon dioxide in the biogas easily and at low cost by using the fermentation broth without using an absorbent for absorbing carbon dioxide, etc., so that the concentration of useful components is increased. Can be purified.

  The biogas generation system according to the second aspect of the present invention includes a fermenter for fermenting organic waste to generate biogas, and the biogas is sent from the fermenter, and desulfurized with respect to the biogas. A biogas generation system comprising a biological desulfurization tower for performing treatment, wherein the dissolved carbon dioxide gas in the fermentation liquor is partly removed from the fermenter and is higher than the temperature in the biological desulfurization tower. Is further configured to introduce a gas-reduced fermentation broth treated by the fermentation liquor gas reduction treatment means into the biological desulfurization tower.

  The biodesulfurization tower oxidizes hydrogen sulfide contained in the biogas produced in the fermenter to sulfuric acid by bringing it into contact with the sulfur-oxidizing bacteria supported on the support in the biodesulfurization tower in the vicinity of the neutral region. And remove the role. Sulfur-oxidizing bacteria are activated by supplying water, low-order sulfur oxides and nutrients. The present invention uses a fermented liquid as moisture supplied to activate sulfur-oxidizing bacteria, and sends this fermented liquid as a “gas-reduced fermented liquid” with increased carbon dioxide absorption capacity when supplying the fermented liquid to the desulfurization tower. In this way, carbon dioxide in biogas is absorbed and taken into the “gas-reducing fermentation liquor”.

That is, according to the present invention, a fermentation liquid partially taken out from the fermenter, and the dissolved carbon dioxide gas in the fermentation liquid at a temperature higher than the temperature in the biological desulfurization tower is reduced to increase the carbon dioxide absorption capacity. ing. When the gas-reducing fermentation liquor with increased carbon dioxide absorption capacity is introduced into the biological desulfurization tower, hydrogen sulfide in the biogas sent from the fermenter is activated to sulfuric acid by activating sulfur-oxidizing bacteria with its moisture. At the same time, the carbon dioxide in the biogas is brought into gas-liquid contact, and the carbon dioxide is reliably absorbed into the gas-reduced fermentation broth. Thereby, the content of carbon dioxide in the biogas is reduced, and the proportion of active ingredients such as methane gas can be easily increased.
Thus, according to the present invention, carbon dioxide in biogas can be removed easily and at low cost by using the fermentation broth itself without using an absorbent for absorbing carbon dioxide and the like, and thus useful components. It can be purified to biogas with increased concentration.

The biogas generation system according to a third aspect of the present invention is the biogas generation system according to the first aspect or the second aspect, wherein the fermentation liquid gas reduction processing means includes a diffusion means for releasing carbon dioxide from the partially extracted fermentation liquid. It is characterized by having.
Thereby, the structure of the fermentation liquor gas reduction processing means can be simplified, and the content of carbon dioxide dissolved in the fermentation liquor can be easily reduced.

The biogas generation system according to a fourth aspect of the present invention is characterized in that, in the third aspect, the fermentation gas reduction processing means further comprises heating means for heating the fermentation liquid to raise the temperature. It is what.
Thereby, in the fermentation liquid gas reduction process by the fermentation liquid gas reduction processing means, the content of carbon dioxide dissolved in the fermentation liquid can be reduced efficiently and reliably.

The biogas generation system according to the fifth aspect of the present invention is the biogas generation system according to any one of the first to fourth aspects, wherein the fermentation solution gas reduction processing means exerts a sterilization effect on the fermentation solution. It is characterized by having a configuration for holding for a predetermined time at a temperature or higher.
When the fermented liquid is used for liquid fertilizer, the fermented liquid is sterilized by heating at 70 ° C. for 1 hour or 55 ° C. for 6 hours. According to the present invention, the heating step for sterilization can be combined with the heating step for reducing dissolved carbon dioxide in the fermentation broth, which is efficient.

  In the biogas production method according to the sixth aspect of the present invention, biogas is produced by fermenting organic waste in a fermenter, and the dissolved carbon dioxide gas in the fermentation liquor partially taken out from the fermenter is reduced. The gas-reduced fermentation liquor that has been treated and brought into gas-liquid contact with the biogas is made to absorb carbon dioxide in the biogas into the gas-reduced fermentation liquor to produce purified biogas. Thereby, the same effect as a 1st aspect can be acquired.

  In the biogas production method according to the seventh aspect of the present invention, a biogas is produced by fermenting organic waste in a fermenter, and the biogas is passed through a biological desulfurization tower to perform a desulfurization treatment, thereby purifying biogas. Is a fermentation liquid extracted partially from the fermenter, and after the carbon dioxide treatment of the fermentation liquid at a temperature higher than the temperature in the biological desulfurization tower, it is introduced into the biological desulfurization tower To do. Thereby, the same effect as the 2nd mode can be obtained.

  According to the present invention, carbon dioxide in biogas can be removed easily and at low cost by using the fermentation broth itself without using an absorbent for absorbing carbon dioxide and the like, thereby reducing the concentration of useful components. It can be refined to enhanced biogas.

An embodiment of a biogas generation system according to the present invention will be described in detail with reference to FIGS. 1 and 2. FIG. 1 is a schematic configuration diagram showing an aspect of a biogas generation system according to the present invention, and FIG. 2 is a configuration diagram of a fermentation liquor gas reduction processing apparatus.
Biogas includes methane fermentation and hydrogen fermentation, and the present invention can be similarly applied to each of these fermentations. In the following description, a biogas generation system based on methane fermentation will be described. However, a biogas generation system based on hydrogen fermentation is almost the same process or system.

  The biogas generation system of FIG. 1 includes, as main components, a fermenter 3 in which biomass, that is, organic waste, is sent to ferment the organic waste to produce biogas 1 and fermentation broth 2, The biogas 1 is sent from the fermenter 3 through the biogas line 4 to the lower part thereof, and a biodesulfurization tower 5 that performs desulfurization treatment by bringing the biogas 1 into contact with sulfur-oxidizing bacteria is provided.

  Furthermore, the fermented liquid gas reduction processing apparatus which carries out the reduction processing of the dissolved carbon dioxide gas in the fermented liquid of the temperature higher than the temperature in the biological desulfurization tower 5 from the fermenter 3 through the extracting line 6 from the fermenter 3. 8 is provided. The gas reduced fermentation liquor 9 processed by the fermentation liquor gas reduction processing device 8 is sent to the circulating liquid tank 11 via the feed line 10.

  The gas-reduced fermentation broth 9 in the circulating liquid tank 11 is sent to the upper spraying section 13 in the biological desulfurization tower 5 via the introduction line 12A, and is sprayed into the tower from the spraying section 13; A part of it is returned to the circulating fluid tank 11 via the return line 12B. In FIG. 1, reference numeral 30 indicates a circulation pump, and reference numeral 31 indicates a stirrer. Thus, the gas-reduced fermentation broth 9 circulates in the biological desulfurization tower 5 as a circulating liquid, and continuously contacts the sulfur-oxidizing bacteria 41 supported on the support 40. As a result, the sulfur-oxidizing bacteria 41 are activated and act on the hydrogen sulfide in the biogas 1 sent from the biogas line 4 into the tower to oxidize it to sulfuric acid.

  At the same time, the gas-reduced fermentation broth 9 sprayed into the tower from the spray section 13 comes into gas-liquid contact with the biogas 1 sent from the biogas line 4 into the tower. Thereby, the carbon dioxide contained in the biogas 1 is absorbed into the gas-reducing fermentation liquid 9 in a state in which the carbon dioxide absorption capacity is increased, and the content of carbon dioxide in the biogas 1 is reduced. A purified biogas with an increased content of active ingredients such as can be obtained.

Specifically, the biogas 1 is held in the biological desulfurization tower 5 for 1 minute or more, preferably 3 minutes or more, and L of the flow rate L (liter) of the gas-reducing fermentation liquid with respect to the supply flow rate G (m ³ ) of the biogas 1. The / G value is set to 0.1 to 100, preferably 1 to 50. The biological desulfurization tower 5 has a known packed tower or plate tower structure.

  A part of the gas-reducing fermentation liquor 9 that has become the circulating liquid is extracted from the bottom of the biological desulfurization tower 5 into the slurry tank 60 via the extraction line 50. Thereby, the sulfuric acid is also extracted. Moreover, most of the fermentation liquor 2 is extracted from the bottom of the fermenter 3 via the line 55 and sent into the slurry tank 60, where it is stored for several months.

  The gas-reduced fermentation liquor 9 sprayed in the biological desulfurization tower 5 is not circulated in the circulating liquid tank 11, but is dispersed in the biological desulfurization tower 5, and then the whole amount is slurried from the bottom of the tower. It is also possible to send it to the tank 60. Thereby, a carbon dioxide absorption ability can always be made into a high state. In this case, the circulating fluid tank 11 is merely a temporary storage tank, and the return line 12B is unnecessary.

  Next, based on FIG. 2, the structure of the fermented liquid gas reduction processing apparatus 8 of a present Example is demonstrated in detail. The fermented liquor gas reduction processing device 8 of the present embodiment is configured to emit carbon dioxide from a heating device 14 that heats the fermented broth 7 and raises the temperature thereof, and a fermented liquor 17 that has a temperature higher than that in the biological desulfurization tower. A diffusion device 15 for reducing fermentation broth 9 is provided. Further, a storage tank 18 is provided between the heating device 14 and the diffusion device 15 via a line 16 and holds the fermentation broth 17 heated by the heating device 14 for a certain period of time. The liquid storage tank 18 is configured to be held for a predetermined time at a temperature higher than a temperature at which a sterilizing effect is exerted on the fermentation liquid.

  The heating device 14 raises the temperature of the fermentation broth 7 partially taken out from the fermenter 3 to a temperature higher than the temperature in the biological desulfurization tower 5, and the fermentation liquid 7 is lower than the temperature in the biological desulfurization tower 5. Is heated to a temperature higher than the temperature in the biological desulfurization tower 5, and when the fermentation liquid 7 is higher than the temperature in the biological desulfurization tower 5, the temperature is the temperature in the biological desulfurization tower 5. It is heated and kept warm so as not to fall below. The heating device 14 is composed of a heat exchanger 19 using hot water (about 80 ° C.) of biogas cogeneration (not shown) in the present embodiment. Of course, it is not limited to this heat exchanger 19 and may be other heating means such as a boiler using biogas.

  The stripping device 15 diffuses dissolved carbon dioxide from the fermentation liquid 17 having a temperature higher than the temperature in the biological desulfurization tower to obtain a gas-reduced fermentation liquid 9. In this embodiment, the gas-liquid such as a packed tower or a plate tower is used. It is comprised with the carbon dioxide stripping tower 20 provided with the contact function. The carbon dioxide stripping tower 20 includes a sprinkling part 21 of the fermentation broth 17 and a blower 22, and air between the air 23 supplied from the blower 22 and the high-temperature fermentation liquid 17 sprinkled from the sprinkling part 21. The dissolved carbon dioxide in the fermentation broth 17 is released to the outside by the stirring action by the liquid contact. The air containing carbon dioxide due to the emission is discharged out of the carbon dioxide emission tower 20 from the outlet 24. The gas-reduced fermented liquid 9 from which carbon dioxide has been diffused from the fermented liquid 17 is sent to the circulating liquid tank 11 via the feed line 10.

Specifically, the air 23 is held in the carbon dioxide stripping tower 20 for 1 minute or more, preferably 3 minutes or more, and L / G of the flow rate L (liter) of the fermentation liquid with respect to the supply flow rate G (m ³ ) of the air 23. The value is set to 0.1-10. In addition, the preferable range of this L / G value changes with kinds and log | history of fermentation broth.

  The liquid storage tank 18 is configured to hold a fermentation solution 17 having a temperature higher than the temperature in the biological desulfurization tower for a certain period of time and exert a sterilization effect on the fermentation solution. A heat retaining means (not shown) is provided. In this embodiment, the fermentation liquid 17 heated to 70 ° C. is configured to be stored and held for 1 minute. In addition, you may make it hold | maintain at 55 degreeC for 6 hours. The standard for setting the capacity of the liquid storage tank 18 is preferably 1.5 to 3 times the amount of the extracted fermented liquid, for example, 50 to 90 liters when the amount of the extracted liquid is 30 liters / hour.

  As for the fermenter 3, organic waste is supplied in the tank from the supply part 80. FIG. The organic waste is methane-fermented by methane-fermenting bacteria in an anaerobic atmosphere in the fermenter 3 to produce biogas 1 and fermentation broth 2. The temperature in the fermenter 3 is set to 55 ° C., and high-temperature methane fermentation is performed. The residence time of the organic waste in the fermenter 3 is set to, for example, 15 days (tank volume / injection / extraction amount = 15 days).

  Examples of the organic waste (biomass) used in the present invention include garbage, wastewater treatment sludge, livestock waste, and green farm waste. Here, livestock waste includes livestock manure, carcass, and processed products thereof. More specifically, livestock manure such as pigs, cattle, sheep, goats, chickens, and carcasses thereof, In addition to bone, meat, fat, internal organs, blood, brain, eyeballs, skin, hoofs, horns, etc. isolated from, such as bones, meat, etc. of livestock carcasses represented by meat and bone meal, meat meal, bone meal, blood meal Also included are crushed crushed materials and dried products obtained by drying blood and the like. Other waste includes household waste, agricultural / fishery waste, food processing waste, etc. as business waste. Depending on the state of the organic waste, a crushing / sorting step can be performed as a pretreatment if necessary.

Next, the operation of the above embodiment will be described.
According to the present embodiment, first, a part of the fermenter 3 taken out from the fermenter 3 is subjected to a treatment for reducing the dissolved carbon dioxide gas in the fermented liquid 17 by reducing the temperature of the fermented liquid 7 higher than the temperature in the biological desulfurization tower 5. Increases absorption capacity. When the gas-reducing fermentation liquor 9 having an increased carbon dioxide absorption capacity is introduced into the biological desulfurization tower 5 in this way, the sulfur-oxidizing bacteria 41 are activated by the water and the biogas 1 sent from the fermenter 3 is sent. At the same time that hydrogen sulfide is oxidized to sulfuric acid, the carbon dioxide in gas-liquid contact with the carbon dioxide in the biogas 1 is reliably absorbed into the gas-reduced fermentation broth 9. Thereby, the content of carbon dioxide in the biogas 1 is reduced, and the proportion of active ingredients such as methane gas can be easily increased.
As described above, according to the present embodiment, carbon dioxide in the biogas 1 can be removed easily and at low cost using the fermentation broth without using an absorbent for absorbing carbon dioxide. And can be purified to biogas with a high concentration of useful components.

  Moreover, since the fermented liquid gas reduction processing apparatus 8 is equipped with the heating apparatus 14 and the liquid storage tank 18 which are the structure hold | maintained for the predetermined time above the temperature which exhibits the sterilization effect with respect to the fermented liquid 7, this sterilization processing is carried out. Therefore, it is possible to share the heating process part for the heating process part for reducing the dissolved carbon dioxide in the fermentation broth, which is efficient.

[Other embodiments]
FIG. 3 is a schematic configuration diagram showing another aspect of the biogas generation system according to the present invention. In this embodiment, the heating device 14 is a dedicated heating device for making liquid fertilizer. A part of the fermented liquid heated by the dedicated heating device 14 for liquid fertilizer is sent to the storage tank. Since the other configuration is the same as that shown in FIG. 1, the same reference numerals are given to the same portions and the description thereof is omitted. Also in this aspect, the same effect as the aspect of FIG. 1 is obtained.

  In the above-described embodiment shown in FIGS. 1 and 3, the gas-reduced fermentation liquor 9 with enhanced carbon dioxide absorption capacity is introduced into the biological desulfurization tower 5 and brought into gas-liquid contact with the biogas 1 in the tower. However, in addition to the biological desulfurization tower, a dedicated gas-liquid contact tower for absorbing carbon dioxide in the biogas can be provided. If it does in this way, since sulfuric acid does not increase in a gas reduction fermentation liquid, it will become easy to use for liquid manure.

<Example 1>
The biomass centered on milked cow manure is fed to the fermenter ³ with a capacity of 60 m ³ at a supply rate of 4 t / day, and the amount of the extracted fermentation broth 7 is 0.7 m ³ / day, kept at 70 ° C. for 1 hour. Then, it was sent to a circulating liquid tank having a capacity of 100 liters, and the gas-reduced fermentation liquid 9 was circulated in the biological desulfurization tower 5 at a circulating flow rate of 10 liters / minute. The flow rate of biogas 1 (methane gas: about 50% by volume, carbon dioxide: about 50% by volume) fed into the biological desulfurization tower 5 was 140 m ³ / day. Incidentally, the fermentation liquid 2 is sent at 3.3 m ³ / day from the fermentor 3 to the slurry tank 60 of capacity 800 m ^3. At this time, the hydrogen sulfide concentration in the purified biogas was 0 ppm, the methane gas concentration was about 65% by volume, and the carbon dioxide concentration was about 35% by volume.

<Example 2>
The biogas desulfurization using the present invention and the increase in calorie absorption to absorb carbon dioxide were carried out in the biogas plant for treating the livestock waste of about 70 t / day centered on milking cow manure as in Example 1. . Fermenter 3 of this plant is a 55 degreeC high temperature fermentation system.
Livestock waste (milking cow manure) was fed to the fermenter ³ with a capacity of 980 m ³ at a supply rate of about 70 t / day, and the amount of the extracted fermentation broth 7 was 15 m ³ / day. The extracted fermented broth 7 is kept at 55 ° C., removed from the lump using a mesh screen having a pore size of about 4 mm in contact with the atmosphere, and the dissolved carbon dioxide gas in the extracted fermented broth 7 is diffused to reduce the gas. The fermented liquid 9 was sent to a circulating liquid tank having a capacity of 300 liters, and the gas-reduced fermented liquid 9 was circulated in the biological desulfurization tower 5. Two types of pumps for the circulating liquid of the biological desulfurization tower for circulating the gas-reducing fermentation liquid 9 in the biological desulfurization tower 5 are prepared (Example 2-1: 0.25 kW, Example 2-2). : 0.4 kW), the hydrogen sulfide concentration and the methane gas concentration in the purified biogas at each circulating fluid amount were measured, and the difference in the output of the biogas engine was examined. Moreover, in a comparative example, the lump was removed without making the extraction fermentation liquid 7 contact with air | atmosphere, and the fermentation liquid in which the dissolved carbon dioxide gas in the extraction fermentation liquid 7 was not diffused was circulated in the biological desulfurization tower 5. . The flow rate of the biogas 1 fed into the biological desulfurization tower 5 (methane gas: about 55% by volume, carbon dioxide: about 45% by volume, hydrogen sulfide concentration: about 3000 ppm) is 2400 m ³ / day. Table 1 shows the test results in Example 2.

  In the comparative example, the fermented liquid that has been circulated in the biological desulfurization tower 5 and does not dissipate the dissolved carbon dioxide gas in the extracted fermented liquid 7 has almost no carbon dioxide absorption capacity because the dissolved carbon dioxide concentration is saturated. The ratio of the methane concentration and the carbon dioxide concentration in the biogas 1 sent into the biological desulfurization tower 5 and the purified biogas hardly changes. The average output of the gas engine using the purified biogas of Comparative Example 1 was about 160 kW.

  In Example 2-1, in which the same amount of gas-reduced fermentation liquor 9 as in the comparative example was circulated in the biological desulfurization tower 5, carbon dioxide in the biogas 1 was absorbed by the gas-reduced fermentation liquor 9, thereby purifying. The methane concentration in the biogas was increased to about 65% by volume, and the average output of the gas engine was improved by 3 kW from the comparative example.

In Example 2-2 in which the amount of gas-reducing fermentation liquor 9 sent to the biological desulfurization tower 5 was increased using a pump having a higher output than that of Example 2-1, the amount of carbon dioxide absorbed by the gas-reducing fermentation liquor 9 was also increased. The methane concentration in the purified biogas was further increased, and a purified biogas having a methane concentration of about 80% by volume was obtained. The gas engine average output of the purified biogas obtained in Example 2-2 is about 166 kW, and an increase in energy consumption (+0.15 kW) due to the use of a pump (0.4 kW) having a higher output than the comparative example. Even if is subtracted, the average power output of the gas engine of about 5.85 kW increases.
Even if the methane concentration in the purified biogas is increased to about 80% by volume or more, the increase in the average output of the gas engine converges, so that the purified biogas having a methane concentration of about 80% by volume can be obtained efficiently. If the amount of gas-reducing fermentation liquor 9 sent into the desulfurization tower 5 is set, energy efficiency is good.

  The present invention relates to a biogas generation system and a biogas generation method for treating a biogas obtained by methane fermentation of organic waste and purifying it so as to increase the content of an active component such as a flammable component methane gas component. Is available.

It is a schematic block diagram which shows the biogas production | generation system which concerns on one embodiment of this invention. It is a block diagram of the fermented liquor gas reduction processing apparatus which concerns on this invention. It is a schematic block diagram which shows the biogas production | generation system which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Biogas 2 Fermentation liquid 3 Fermenter 4 Biogas line 5 Biological desulfurization tower 7 Fermentation liquid 8 taken out partly Fermentation liquid gas reduction processing apparatus 9 Gas reduction fermentation liquid 11 Circulating liquid tank 13 Sprinkling part 14 Heating apparatus 15 Radiation apparatus 17 High-temperature fermentation liquid 18 Storage tank 20 Carbon dioxide stripping tower

Claims (1)

Heating the fermentation liquor partially taken out from the fermenter that ferments organic waste to produce biogas, and performs heat treatment to reduce dissolved carbon dioxide gas in the fermentation liquor,
While utilizing a part of the fermented liquid after the heat treatment for liquid fertilizer,
The other part of the fermented liquid after the heat treatment is supplied to sulfur-oxidizing bacteria supported on a supporting part in a biological desulfurization tower that performs a desulfurization process on biogas, and the fermented liquid is used. A biogas production method.

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