JP2006089668A - Method for producing methane gas and method for generating electricity utilizing the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing methane gas by using a lignin-containing cellulosic material, i.e., a lignocellulosic resource including a woody resource, as a raw material, while the lignin-containing cellulosic material comprises a material which is represented by a woody waste material occurring when a tree is cut, does not pass through a digestive tract of an animal, such as a domestic animal, does not subjected to processing, nor to a decomposition process, for the purpose of being industrially formed into food or fodder, and is unsuitable for the food or a raw material for the food, and to provide a method for generating electricity by utilizing the method. <P>SOLUTION: This method for producing the methane gas comprises forming an aggregate of small chips by crushing a lignocellulosic material, accumulating the aggregate of the chips while giving moisture under an aerobic condition for a prescribed period until at least a start of partial decay caused by attachment of decay fungi thereto is recognized, feeding the accumulated aggregate into a tank, adding water and at least 20 wt% based on a weight of the accumulated aggregate of mud or sludge to the accumulated aggregate, and culturing contents of the tank at a temperature suitable for methane fermentation under an anaerobic condition, wherein the mud or the sludge is cultured with pure agar and then at least a meat juice is added to the agar cultured from the pure agar therewith, before the mud or the sludge is added to the accumulated aggregate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing methane gas and a method for producing electricity using the method. More specifically, it is a material typified by wood-based waste materials that are generated when the tree is cut, never passed through the digestive tract of animals such as livestock, and industrially used as food or feed A lignin-containing cellulosic material, i.e., a lignocellulosic resource including a woody material, which has not been subjected to a processing or decomposition step, and is unsuitable as a food or food raw material, and a method for producing methane gas , It relates to a method of creating electricity using this method.

Lignocellulose is the most abundant organic substance on earth, and is composed of cellulose and hemicellulose, which are structural polysaccharides, and lignin which is a polymer pair of aromatic compounds. Among them, wood-based waste materials become hot when burned, so they are annoying to waste disposal companies, and composting is troublesome because it requires heating (for example, Patent Document 1). There are cases where it is used after being mixed with a molded product or pyrolyzed, but with regard to the treatment that does not apply heat, there is currently research on whether termites can be used, and it cannot be reused. Is currently incinerated or left alone.
JP 2002-326074 A

  When methane gas, which can be generated from organic matter, is released into the atmosphere in an uncontrolled state, it adversely affects the environment as a greenhouse gas having a greenhouse effect about 20 times that of carbon dioxide. On the other hand, if it is generated in the tank so that it does not leak into the atmosphere as a waste treatment process, it should be possible to realize both partial waste treatment and production of useful methane gas at once.

  The usefulness of methane gas is that it can be an energy source as a fuel, can be used as a raw material for producing hydrogen by reforming reaction and direct decomposition used in fuel cells, or a phosphoric acid fuel cell using direct biogas It can be used for

  It is well known that organic matter is converted to methane by methane fermentation by microbial action, and application to waste treatment called digestion gas or biogas (mixed gas of methane, carbon dioxide, etc.) has become popular.

So far, as raw materials or raw materials in methane fermentation or digestion gas or biogas production, raw garbage, cow dung, pig dung, chicken dung and other livestock dung, waste crops, food industry waste, and the like are known. Moreover, generating methane gas using a cellulosic raw material is also described in Patent Document 2, for example.
However, even if it is said to be a cellulosic raw material, there are only known examples using livestock manure that has passed through the gastrointestinal tract and internal organs of animals and has been subjected to various enzyme actions. Absent. According to some information (for example, Non-Patent Document 1), the lignin of livestock dung is different from the lignin of the grazing grass. No. from Tohoku agricultural trial 79, September 1996

Non-Patent Document 2 describes that a mixture of a large amount (probably about 75%) of straw and a small amount (probably about 4%) of vegetation waste is used as a raw material for biogas production. However, it is not known that timber waste is mainly used as a raw material for biogas production for disposal of timber waste. (See also Non-Patent Document 3).
Chisato Dono, Mitsuhiro Hamajima, “Environmental Technology, Biogasification Technology for Garbage (IMC) 29-9”, pp. 676-681, 2000 Kurimoto Works, Mitsuhiro Hamajima, Sachiko Nakamura, Babcock-Hitachi Ltd. Hideharu Mori, Kazuko Shimohira, “Development of Methane Fermentation System for Garbage” http://www.kurimoto.co.jp/ rd / pdf_ronbun / ron110.pdf

By the way, the ease of methanation of organic matter is
Easily degradable organic matter: sugar, starch, water-soluble protein> moderately degradable organic matter: bacterial protein, fat, hemicellulose, non-crystalline cellulose> hardly degradable organic matter: crystalline cellulose, lignocellulose, lignin, hard protein in this order It is said that there is. Regarding biogas, it is stated that “things that are not suitable for raw materials are leeks, onions, garlic, carrots and internal organs of fish and animals, peanuts, brown tea, soybeans, straw, sawdust, paper, etc.” .

  Regarding only the decay of wood waste without methanation, the above-mentioned Patent Document 1 (Japanese Patent Laid-Open No. 2002-326074) states that “wood waste has a low water content, lignin, cellulose, It contains many components that are difficult to microbially decompose, such as hemicellulose, so the fermentation temperature does not rise and it is difficult to obtain sufficient maturity of compost, which rots organic material to the extent that it does not cause crop damage. For this reason, particularly in cold regions, it is necessary to heat the fermenter with a heater or the like in order to ripen the compost, and there has been a problem that energy consumption is further increased due to ripening. ”Disposal of wooden waste is a troublesome problem.

  As mentioned above, despite the use of various waste organic materials (including livestock manure as lignocellulosic resources) as raw materials for methane fermentation and biogas production, Lignocellulosic resources that do not pass through the gastrointestinal tract of livestock, such as branches of trees that have been cut off, despite the generation of waste as cellulosic resources, are one form of organic matter that exists in the largest amount on earth. However, it has not been used as a raw material for methane fermentation or bioproduction. Furthermore, until now, the production of biogas using garbage etc. has not produced much methane.

  Therefore, in spite of the presence of a large amount of raw materials, lignin binding that has not passed through the gastrointestinal tract of livestock, such as tree branches that have been considered unsuitable as a raw material for generating methane gas. It can be said that it is extremely valuable if methane gas can be produced using a cellulosic material or waste material used as a raw material for generating methane gas.

  In order to achieve these objects, as a result of intensive research, the present inventor has succeeded in developing a technology that makes it possible, and has already filed a patent application (Application No .: Japanese Patent Application No. 2003-034430, Application date: February 12, 2003). By the way, the gist of these techniques is as follows.

  In other words, it is a material containing a woody part that was part of a plant body, never passed through the digestive tract of animals such as livestock, and processed or decomposed to make it industrially food or feed In the case of using a material containing cellulosic substance with lignin, which has not been subjected to the process and is not suitable as a food or food raw material, the material is pulverized into a fine chip aggregate. This chip aggregate is deposited for a certain period of time until the start of decay is recognized at least partially due to the attachment of decaying fungi, while maintaining the shape of the chip under aerobic conditions while applying moisture. Placing the deposit in a tank, adding water and at least 20% by weight mud or sludge to the weight of the deposit, and subjecting the tank contents to anaerobic conditions at a temperature suitable for methane fermentation. And culture, from the tank to the place to take out the methane gas.

When using raw garbage as a raw material,
(a) If necessary, grind the raw garbage brought in from the carry-in entrance, and then stir it in a stirring tank with mud or sludge rich in aqueous anaerobic bacteria.
(b) Put this agitation into a silo under anaerobic conditions and hold it in this silo for a certain period of time to decompose garbage.
(c) collecting and collecting methane gas generated in the silo from the silo;
By the way.

  It has been found that by adopting these methods, methane gas can be generated more efficiently than in the conventional case. However, the present inventor has made further research to determine whether a larger amount of methane gas can be generated. I continued exploring. As a result, we finally came to find the method.

  The method is to add the mud or sludge to pure agar before adding the mud or sludge to the sediment or raw garbage or ground garbage after pulverization, and add at least gravy to the pure agar-cultivated agar, This mixture is characterized in that it is added to the deposits, garbage or crushed garbage. That is, in addition to culturing mud or sludge in pure agar, adding at least gravy to pure agar-cultured agar, and adding this mixture to the sediment, the garbage or the crushed garbage, the generation of methane gas Can be promoted.

  After adding gravy to pure agar cultured agar, it may be further cultured. By this culture, generation of methane gas can be further promoted.

When the mud or sludge is cultured on pure agar, the mud or sludge is preferably cultured on the agar culture bed at a certain temperature, for example, about 35 ° C. for about a week. In that case, the amount of mud or sludge is preferably about 500 g to 1 kg with respect to 2 kg of the agar culture bed. Further, the culture period after adding the meat juice to pure agar cultured agar is preferably about one week.
“Meat broth” refers to a gelatinized form of boiled beef, pork, chicken and other various meat fats, and the amount added is preferably about 10 g.

  More specifically, the mud or sludge is suitable for the habitat of both hydrogen-producing bacteria and methane-producing bacteria and contains these fungi, or mud soil in a lotus field with water or It is selected from the group consisting of sludge, sludge or sludge at the bottom of stagnation of river water that contains organic matter to some extent due to sludge, domestic wastewater, hot spring bath drainage, etc., and sludge or sludge at the bottom of lakes that contain a lot of organic matter Muddy soil or sludge.

  “Muddy soil” means a muddy soil with physical properties such as mud. When “sadro” means mud containing organic matter precipitated on the bottom of the water, it can be included in “mud”. “Sludge” may also be included in “mud”. Where a weight percentage of such mud relative to the weight of the ground decay decay chip deposit is indicated, it is expressed as a weight percentage of such moisture content and not a percentage of dry matter.

Regarding "mud soil suitable for the habitat of both hydrogen-producing bacteria and methane-producing bacteria and containing these bacteria", the nutrients used by hydrogen-producing bacteria and methane-producing bacteria are said to be different, but anaerobic It is thought that there are methane producing bacteria where hydrogen producing bacteria exist.
For “mud or sludge that is suitable for the habitat of both hydrogen-producing bacteria and methane-producing bacteria and contains these bacteria”, as an example, in a place where the soil is also rich in proteolysates or organic matter. If the soil is anaerobic (eg, at the bottom of the water), the water is not flowing and stagnant, and the water is not soiled (the water above is clear) Such mud or sludge is thought to be suitable for the habitat of both hydrogen producing and methane producing bacteria.
Mud or sludge in lotus field with water, mud or sludge at the bottom of river stagnation that contains organic matter to some extent due to domestic wastewater or hot spring bath drainage, etc. and lakes rich in organic matter The bottom mud or sludge meets these conditions.

Examples of woody materials include one or more selected from the group consisting of disposal materials generated by cutting branches and trunks of trees, fallen trees, discarded trees and parts thereof, and fallen leaves, or substantially Or a mixture of one or more selected from the group consisting of waste vegetables, weed garbage, straw, and raw garbage. Waste wood and wood chips generated in the lumbering process and demolition may be used as woody raw materials, but in recent years, mainstream foreign timber has been invaded by seawater, and new construction materials contain chemical substances. In many cases, it is not suitable.
The wood material is preferably crushed to such an extent that it can pass through the eyes of an 8 mm sieve. Since woody waste contains twigs or is fibrous and elongated, it also includes fragments with a length longer than 8 mm. For example, it can be pulverized to about 2 cm in advance, and then pulverized to such an extent that it passes through the eyes of an 8 mm sieve.

  About 60% of the moisture content of the entire sediment when the wood material crushed chips are deposited and decayed is preferable. At the stage of sedimentation and decay, it is only necessary to ventilate the water to make it aerobic, and no other mixing is necessary. Mixing can be counterproductive. For example, when rot was attempted by mixing residues of the fungi of sea bream (nameko and shimeji), there was an adverse effect on the subsequent methane fermentation stage. It was observed that the temperature rose to about 50-60 ° C. during the deposition stage. The deposition period is preferably 20-30 days. In other words, it is the time when the decay has started a little after the start of decay, and the shape of the chip is maintained.

  It is estimated that the efficient methane production of the present invention in the case where the wood material pulverized material decay chip is used as a raw material undergoes the following process. Aerobic decay is caused by the fact that the wood decay fungus adheres to the surface of the ground material due to the accumulation of the ground material of the wood material under aerobic conditions, and the ground material that has been partially decayed is immersed in water. Bacteria produce fine bubbles on the surface of the pulverized product. In the state where the oxygen in the bubble is exhausted, the decaying bacteria die, and instead, the anaerobic hydrogen-producing bacteria in the mud or sludge are easily propagated at the interface between the bubble and water. Hydrogen-producing bacteria break down cellulose, hemicellulose, etc., the bond between lignin and cellulose is destroyed and the pulverized product becomes soft, and the methane-producing bacteria that existed in the mud or sludge that nourished it by the growth of hydrogen-producing bacteria It is thought to breed and produce methane.

  On the other hand, the efficient methane production of the present invention when raw garbage is used as a raw material is also produced by the production of methane that was present in the mud or sludge that is nourished by the hydrogen-producing bacteria, and the garbage is decomposed by the reproduction of hydrogen-producing bacteria. It is thought that fungi propagate and produce methane.

  Before adding the mud or sludge to the sediment in the tank or the garbage in the stirring tank or the ground garbage after pulverization, the mud or sludge is cultured in pure agar, and at least the agar cultured in pure agar Generation of methane gas can be promoted by adding gravy and adding this mixture to the deposits in the tank, the garbage in the stirring tank or the garbage after pulverization.

  In order to store the produced methane, the produced methane is adsorbed on activated carbon on which water is adsorbed. In this way, the produced methane can be stored efficiently and safely.

  In order to generate electricity, methane gas may be supplied to the raw material for the fuel cell. This is very convenient because the production of methane can be used directly in combination with a fuel cell.

  According to the method of claim 1, methane gas can be produced efficiently and in large quantities using lignocellulosic resources and mud or sludge, which are inexpensive and easy to obtain. .

  According to the method of Claim 2, methane gas can be efficiently produced | generated in large quantities using a raw soil as a raw material and using mud or sludge.

  According to the method of Claim 3, generation | occurrence | production of methane gas can be promoted more.

  According to the method of claim 4, the methane gas is efficiently produced in a large amount by using mud or sludge that does not incur raw material costs, is easily available, and does not have to worry about depletion even when used. Can be generated.

  According to the method of claim 5, methane gas can be generated efficiently and in a large amount using a material that is inexpensive and easily available.

  The method according to claim 6 is suitable for decaying a pulverized wood material.

  The method according to claim 7 is suitable for decaying a pulverized wood material.

  The method according to claim 8 can produce methane gas in an environment suitable for producing methane gas.

  According to the method of the ninth aspect, the produced methane can be efficiently and safely stored.

  According to the method of claim 10, since the production of methane can be directly combined with the fuel cell and used, it is very convenient.

  Hereinafter, embodiments of the present invention will be described in detail. However, the example shown below shows an example to the last, and is not limited to them.

(1) Selection of wood raw materials In the previous application (Application No .: Japanese Patent Application No. 2003-034430, filing date: February 12, 2003) related to the same applicant, both wooden conifers and broad-leaved trees are used as wooden raw materials. And abandoned trees, cuts and leaves (percentage of normal garden tree pruning), including cedar leaves and trunks, deciduous trees, fallen leaves, oak leaves and trunks, all containing both coniferous and broadleaf trees It has been proven that pine needles and trunks can be used. Then, they are pulverized by a pulverizer to obtain a pulverized product (chip) having a size passing through an 8 mm sieve. If pulverization at one time is difficult, a coarsely pulverized product may be used and then finely pulverized again.

(2) Partial decay processing of wooden raw material In the previous application (application number: Japanese Patent Application No. 2003-034430, filing date: February 12, 2003) pertaining to the same applicant, It has been proved that it is good to keep it for 20 days to 1 month while giving wetness at intervals of once every two days. Visually confirm that the internal temperature is about 50 to 60 ° C. and that aerobic heterotrophs recently (mainly white rot fungi and filamentous rot fungi) begin to attach naturally (in about a week). Yes. It has also been confirmed that when oxygen is supplied, earlier attachment of aerobic bacteria is recognized by activation of the aerobic bacteria. In large-scale production, this decaying fungus treatment process only requires water from time to time, and can be deposited outdoors, so it can be used in a relatively small area, so the period of 20 days to 1 month will deteriorate the efficiency of the process. Must not.

(3) Selection of mud In the previous application related to the same applicant (application number: Japanese Patent Application No. 2003-034430, filing date: February 12, 2003), the above step (2), that is, the wood raw material Wood material pulverized chips decayed chips with decaying fungi that have been partially decayed obtained in the partial decay treatment process (hereinafter referred to as crushed product decay chips or wood material crushed decay chips 1 kg) is put into a 10 liter container, 50% by weight of water is added to the weight of the crushed decayed chips, and various weights of 30% to 50% by weight are added to the weight of the crushed decayed chips. We tried to investigate the amount of methane gas generated for each sample by adding mud. As a result, it has been proved that the mud in the lotus root field is the most suitable as the mud component, and the mud in the downstream of the Muddy River is the second most suitable. In this experiment, among the mud components that can be used for the generation of methane gas, two types of mud in the lotus field, which had the best results, and the mud in the downstream of the Nakugawa, which had the best results, were used. Use as In addition, the mud in the downstream of Muddy River refers to the mud immediately downstream of the hot spring town.

(4) Pure Agar Culture of Mud In the present invention, the mud is subjected to pure agar culture before adding the mud or sludge (hereinafter simply referred to as mud) to the crushed material decay chip. When the mud is cultivated in pure agar, the mud is preferably cultivated for about a week while maintaining a constant temperature, for example, about 35 ° C., on the agar culture bed. In this case, the amount of mud is preferably about 500 g to 1 kg with respect to 2 kg of the agar culture bed.

(5) Addition of gravy Add at least gravy to agar cultured on pure agar. “Meat broth” refers to a gelatinized form of boiled beef, pork, chicken and other various meat fats, and the amount added is preferably about 10 g. After adding gravy to pure agar-cultured agar, it is preferable to maintain a certain temperature, for example, about 35 ° C., and further culture for about one week.

(6) Methane gas generation Put 1kg of crushed decay chips into a 10-liter container, add 50% water by weight with respect to the weight of the crushed decay chips, and crush agar cultured for about a week after adding meat juice 50% by weight was added to the weight of the decayed chip and air purge with nitrogen was performed. At that time, although the inside of the container was in a low oxygen state, the temperature therein was kept at 35 ° C., and the amount of methane gas generated was measured from 1 week to about 8 weeks later. The measurement of methane gas was performed based on the JIS K 2301 gas chromatography (TCD) method. In addition, since tap water may have a bactericidal action, the water used here used well water (soft water).

(7) Collection of methane gas The methane gas collection experiment was conducted in a 10-liter plastic tank. Then, a value of one time of one week to two weeks or the period of about 8 weeks from the preparation was recorded as a result.

(Examples 1 and 2)
The numerical values in the case of Example 1 and Example 2 are shown in Table 1 and FIG. 1 (graph). In Example 1, pure agar culture of the lotus field mud is added, and after adding gravy to the agar, further cultured agar is used. In Example 2, the mud of Mudagawa is pure agar cultured, and gravy is added to the agar. After the addition, further cultured agar was used.

(Comparative Example 1)
The fact that generation of methane gas is recognized even when mud soil that has not been subjected to pure agar culture is added to the crushed material decay chip indicates that an earlier application related to the same applicant (application number: Japanese Patent Application No. 2003-344430, application date: 2003) (February 12, 2012). The data is shown in Table 2 as Comparative Example 1.

As is clear from Table 1 and Table 2, in the case of Examples 1 and 2 (when mud was cultured in pure agar and gravy was added to the agar), mud that was not cultured in pure agar (without gravy added) Compared to the case of using), it was demonstrated that the amount of methane gas generated was greatly increased.

(Comparative Examples 2 and 3)
In order to demonstrate the quality of the addition of the gravy, the lotus soil in the lotus root is cultured on pure agar, and the same amount of potato (starch flour) is added to the agar instead of the gravy in Examples 1 and 2, and then Further, using the cultured agar, a methane gas collection experiment was performed in the same manner as in Examples 1 and 2. In addition, in the case of Examples 1 and 2, pure mud of mud river was cultured in pure agar, and the same amount of potato was added to the agar instead of the gravy in Examples 1 and 2, and then further cultured agar was used. The methane gas collection experiment was conducted in the same way as the above. The results are shown in Table 3 as Comparative Example 2 and Comparative Example 3. Moreover, the result of Table 3 is shown with a graph in FIG.

As is clear from Tables 1 and 3 and FIGS. 1 and 2, in the case of Examples 1 and 2 (when meat juice was added), the mud was subjected to pure agar culture, and Examples 1 and 2 were applied to the agar. It was demonstrated that the amount of methane gas generated was greatly increased compared to the case where potato (potato starch) was added in place of the meat juice.

(Comparative Examples 4 to 10)
On the other hand, in order to demonstrate the quality of using the pulverized material decay chip, various organic substances shown below were used instead of the pulverized material decay chip, and the methane gas collection experiment was performed in the same manner as in Examples 1 and 2. Went. The results are shown in Tables 4 to 7 as Comparative Examples 4 to 10.
Various organic materials: Okara, mushrooms (nameko), mushrooms (shimeji), mushrooms (enoki), rice bran, rice bran, leftovers

As is clear from Tables 4 to 7, organic matter other than crushed and decayed chips, even if mud is subjected to pure agar culture and the agar is used, the amount of methane gas generated is very small or cannot be collected. It was proved that.

(Comparative Example 11)
Further, using the organic materials shown below instead of the organic materials described above, a methane gas collection experiment was performed in the same manner as in Examples 1 and 2. The results are shown in Table 8 as Comparative Example 11.
Organic quality: Aoko of the river

As is clear from Table 8, it was demonstrated that the amount of methane gas generated was extremely small even when this kind of organic matter generated in nature was used.

(Comparative Examples 12-14)
On the other hand, it has been proposed to use feces of livestock to generate methane gas, and in order to confirm whether it is possible or not, methane gas collection experiment using cow dung, pig dung and chicken dung. I went. The respective results are shown in Tables 9 and 10 as Comparative Examples 12 to 14. The results of Tables 9 and 10 are shown in a graph in FIG.

As shown in Table 1, Table 2, Table 9, Table 10, and FIG. 1 and FIG. 3, before adding mud, when adding mud to the crushed material decay chip and generating methane gas, In addition to culturing the mud with pure agar and adding at least gravy to pure agar-cultivated agar, it has been demonstrated that sufficient results can be obtained, although not as much as with cow dung, pig dung, and chicken dung.

  Next, for the sample B, the number of bacteria in the sample B was counted by a direct counting method by the method shown below.

(Pretreatment of sample)
About 5 g was collected from the sample, added with an extraction buffer (100 mM Tris-HCL [pH 9.0], 50 mM EDTA), and dispersed with a homogenizer (ACE homogenizer [Nippon Seiki Seisakusho, Tokyo]) (15000 rpm, 15 minutes). And transferred to a sterilized 50 mL tube.

(Counting the number of bacteria in the sample)
A diluted solution was prepared with sterilized water using the pretreated sample as a stock solution, and filtered through a Nuclepore filter having a pore diameter of 0.2 μm that had been stained in black with Sudan Black in advance, and the suspension in the sample was recovered. Two filters were prepared for each sample. A filtered filter mounted on a slide glass is examined using a non-fluorescent emulsion oil and an epifluorescence microscope (Olympus AX80 [Olympus Optical Co., Ltd., Tokyo]) mounted with a 100 × objective lens (UplanApo 100xOI). Mirrored. Olympus U-MWBV for BV excitation observation (dichroic mirror DM455, excitation filter BP400-440, absorption filter BA475) was used as a filter cube for observing F-420 autofluorescence possessed by methane bacteria.
A counting grid (10 × 10 squares, square shape, side length of 10 μm was 10 μm) was placed on the eyepiece side, and the number of bacteria per arbitrary number of compartments was counted with a counter. Counting was performed for 10 fields per filter, and the number of compartments and the number of bacteria used for counting were recorded. From the average of the number of bacteria obtained for the two filters, the proportion of methane bacteria (number of bacteria) in 1 mL of the sample was determined by the following formula.

Table 11 shows the sheet used in this case. Note that the final amount of the diluted sample used in the production of the filter for counting was 1 μL of the stock solution. The filter filtration area was 193.5 mm ² . When the ratio of methane bacteria per mL of the sample by the direct counting method is calculated from the above formula, it is as follows.
Total number of methane bacteria = 1.46 × 10 ⁹

  As can be seen from the above, when lotus soil in a lotus root is cultured in pure agar, or in mud of pure muddy river, and gravy is added to the agar, and either of them is added to the crushed decay chips. Was able to confirm that the amount of methane gas generated was greatly increased compared to the case of using mud soil without pure agar culture (without meat juice).

  It should be noted that even if the amount of mud (accelerator) is changed, the amount of methane generated does not change because the previous application related to the same applicant (application number: Japanese Patent Application No. 2003-034430, filing date: February 12, 2003). And can be applied to the present invention. That is, even if the amount of mud is changed while a necessary and sufficient amount is supplied, it does not greatly affect the change in the amount of methane produced. This is thought that mud works to promote methane generation in a certain range rather than as a raw material for methane. For example, the idea that it contributes to the supply of microorganisms seems to hold.

Before adding mud to the crushed material decay chip, the mud is pure agar cultured, and after adding gravy to pure agar cultured agar, methane gas is generated using the cultured agar. It is a graph. It is a graph which shows that generation | occurrence | production of methane gas is recognized even if the mud soil which is not cultivated in pure agar is added to the crushed material decay chip. It is a graph which shows the result of having conducted the collection experiment of methane gas using cow dung, pig dung, and chicken dung.

Claims (10)

A material containing a woody part that was part of the plant body, never passed through the digestive tract of animals such as livestock, and processed or decomposed to produce food or feed industrially A crushed material containing cellulosic lignin, which has not been received and is unsuitable as a food or food ingredient, to form an aggregate of fine chips,
This aggregate of chips is deposited for a certain period of time until at least partial start of decay due to adhesion of decaying fungi, with the shape of the chip maintained as it is under aerobic conditions while giving moisture.
Place this deposit in a tank and add water and at least 20% by weight mud or sludge, based on the weight of the deposit,
Culturing the tank contents under anaerobic conditions at a temperature suitable for methane fermentation,
When removing methane gas from this tank,
Before adding mud or sludge to the sediment, the mud or sludge is cultured in pure agar, and at least gravy is added to the agar cultured in pure agar.
Adding this mixture to the deposit to promote the generation of methane gas,
A method for producing methane gas, characterized in that (a) If necessary, grind the raw garbage brought in from the carry-in entrance, and then stir it in a stirring tank with mud or sludge rich in aqueous anaerobic bacteria.
(b) Put this agitation into a silo under anaerobic conditions and hold it in this silo for a certain period of time to decompose garbage.
(c) collecting and collecting methane gas generated in the silo from the silo;
(d) discharging the residue remaining in the silo, and the empty silo again comprises the step of using for the step (b),
In a method for producing methane gas,
Before adding the mud or sludge, the mud or sludge is cultured with pure agar, and at least gravy is added to the agar cultured with pure agar.
Add this mixture to the garbage or crushed garbage to promote the generation of methane gas,
A method for producing methane gas, characterized in that   The method for producing methane gas according to claim 1 or 2, further comprising culturing after adding the meat juice to the agar which has been subjected to pure agar culture.   Use mud or sludge, which is suitable for the habitat of both hydrogen-producing bacteria and methane-producing bacteria, and contains these fungi, or mud or sludge in a lotus field with water, living Mud or sludge selected from the group consisting of mud or sludge at the bottom of river water stagnation that contains organic matter to some extent due to drainage or hot spring bath drainage, etc., and mud or sludge at the bottom of lakes and lakes that contain a lot of organic matter The method for producing methane gas according to any one of claims 1 to 3, wherein sludge is used.   One or more materials selected from the group consisting of disposal materials generated by cutting tree branches and trunks, fallen trees, discarded trees and parts thereof, and deciduous leaves, or a substantial amount thereof The method for producing methane gas according to claim 1, which is a mixture of a small amount or a main amount and at least one selected from the group consisting of waste vegetables, weed garbage, straw, and raw garbage.   The method for producing methane gas according to claim 1, wherein the chip is passed through a sieve having a size of 8 mm.   The method for producing methane gas according to claim 1, wherein the deposition period is 20 to 30 days.   The method for producing methane gas according to claim 1, wherein the temperature suitable for methane fermentation is 25 ° C or higher.   The method for producing methane gas according to any one of claims 1 to 8, further comprising the step of adsorbing the produced methane on activated carbon adsorbed with water for storage.   A method for producing electricity using the method for producing methane gas according to any one of claims 1 to 9, comprising the step of supplying methane gas to a raw material for a fuel cell to generate electricity.

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