JP4936056B2 - Methane fermentation treatment apparatus and methane fermentation treatment method - Google Patents

Description

  The present invention relates to a methane fermentation treatment apparatus that collects resources such as biogas by subjecting organic waste such as garbage to methane fermentation.

  Most organic waste such as garbage and sludge is incinerated or landfilled. However, due to problems such as dioxin generation due to incineration, tightness of landfill sites, and bad odors, treatment methods with low environmental impact are required. It has been. In order to solve these problems, a system has been developed in which organic waste is subjected to methane fermentation treatment, and the generated methane gas is generated using a fuel cell or a gas engine.

  In methane fermentation, organic waste is crushed and slurried, and then this slurry is put into a fermentor and fermented with methane bacteria under anaerobic conditions to convert organic waste into methane gas. Various treatment methods and fermenters have been proposed depending on the properties of the input raw materials and operating conditions. The methane fermentation method is an energy-saving treatment method because organic waste can be decomposed into biogas and water to greatly reduce the amount, and anaerobic power is not required for anaerobic treatment. In addition, there is a merit that methane gas generated as a by-product can be recovered as energy. If methane fermentation is a biodegradable organic waste as a fermentation target, fermentation is possible without problems if sufficient reaction time is secured below the concentration causing ammonia inhibition. In addition, wastes containing high concentrations of saturated fatty acids were dealt with by mixing with other wastes or by reducing the concentration by diluting with water.

In addition, as another conventional technique related to methane fermentation, a technique has been proposed in which concentrated fats and oils and fat-containing waste are uniformly dispersed so that the fats and oils do not become agglomerated (see Patent Document 1). Further, techniques for separating solid components and oil separation using microwaves have been proposed (see Patent Documents 2 to 5).
JP 2002-102828 A JP 2007-29841 A JP 2005-193146 A Japanese Patent Laid-Open No. 2007-811 JP 2006-205087 A

  However, when performing methane fermentation, the organic slurry of the object to be treated is put into the methane fermentation tank. When the concentration of fat in the organic matter to be processed, particularly the saturated fatty acid concentration, increases, Before the oil is decomposed, saturated fatty acids come into contact with each other and repeatedly adhere to cause agglomeration of fat mass, thereby blocking the piping and reducing the volume of the tank itself. In addition, the accumulated fatty acid also becomes an inhibiting factor such as lowering the pH, and the fermentation becomes unstable, so that there is a problem that the fermentation is stopped due to rancidity. Moreover, in the technique of the said patent document 1, although fats and oils are disperse | distributed uniformly so that it may not become a lump shape, and it processes again by slurrying, it becomes a cause by which the lump of fats and oils generate | occur | produces again by this fats and oils, and piping mentioned above The problems of blockage and reducing the volume of the tank itself are not solved.

  Among fats, palmitic acid and stearic acid, which are linear saturated fatty acids, have high melting points of 62.6 ° C. and 70.5 ° C., respectively, and are fatty acids that are difficult to decompose even in high-temperature methane fermentation at 55 ° C. When the content of palmitic acid and stearic acid contained mainly in animal fat is high, a lump of fat tends to be formed. Until now, as a method of performing unique fermentation in which high-concentration saturated fatty acids exist, in order to prevent contact between fats or to disperse them, the method of fermenting in combination with sludge or other organic waste It is common to reduce the concentration of saturated fatty acids such as stearic acid and palmitic acid, which have a high melting point, and prevent fat from being granulated by contact, by increasing the dilution with water or increasing the dilution of water. The actual situation is that no detailed examination has been made on the method of charging into the methane fermenter.

  The present invention has been made in view of the above problems, and even when a lump of fat is generated, a methane fermentation treatment apparatus capable of suppressing clogging in a fermenter due to fat particles and suppressing deterioration of fermentation, and It aims at providing the methane fermentation processing method.

In order to solve the above-mentioned problem, the present invention is a methane fermentation treatment apparatus having a fermenter for methane fermentation of organic waste, which has been extracted from a fermentation liquor extraction port disposed near the bottom of the fermenter. A circulation path for heating the fermentation broth and returning it to the vicinity of the upper part of the fermenter, and an oil content of the fermenter provided at a horizontal position above the fermentation broth outlet and substantially corresponding to the outlet of the circulation path and withdrawn from the withdrawal port, and a oil processing path to introduce the oil processing apparatus for performing processing to prevent the occurrence of lumps of the oil, the processed by the oil processing equipment oil, before during Ki循 ring path. According to this configuration, even if a fat mass is generated, the fat mass can be discharged, and blockage in the fermenter due to fat particles can be suppressed, and deterioration of fermentation can be suppressed.

The said oil content processing apparatus can employ | adopt the structure which cut | disconnects or crushes the oil content extracted from the said fermenter. According to this structure, generation | occurrence | production of the lump of an oil component can be prevented within a fermenter.

  The said oil content processing apparatus can employ | adopt the structure which melt | dissolves the oil content extracted from the said fermenter at the temperature of 80 degreeC or more. According to this configuration, the oil can be solubilized.

  The said oil content processing apparatus can employ | adopt the structure which irradiates and melt | dissolves the oil extracted from the said fermenter by microwaves. According to this configuration, the oil can be solubilized.

  The said oil content processing apparatus can employ | adopt the structure which solubilizes the oil extracted from the said fermenter by hydrothermal reaction. The said oil content processing apparatus can employ | adopt the structure which disperse | distributes the oil content extracted from the inside of the said fermenter with an ultrasonic wave. According to this configuration, the oil can be solubilized.

  The oil component treatment path can be configured to be connected to at least one of the heating apparatus provided in the circulation path and the outlet of the heating apparatus. According to this configuration, since the temperature of the circulating fermentation broth is high in the vicinity of the heating device, the oil component processed by the oil component processing device can be further solubilized.

  The organic waste preferably has an n-hexane extract substance concentration of 2 g / L or more. The content ratio of palmitic acid and stearic acid in the organic waste is preferably 40% or more of the total fatty acids.

The present invention provides a fermenter for methane fermentation of organic waste, and a circulation path for heating the fermented liquor drawn from the fermented liquor drawing port arranged near the bottom of the fermenter and returning it to the vicinity of the upper part of the fermenter And a methane fermentation treatment method using a methane fermentation treatment apparatus having an oil content of the fermenter provided at a horizontal position above the fermentation liquid outlet and substantially corresponding to the outlet of the circulation path a step of extracting the oil from the extraction port, before SL and oil treatment step the oil fraction performs processing to prevent the occurrence of lumps of the oil, the oil treated with the oil processing step, pre Ki循 ring pathway And a charging step for charging to the. According to this configuration, even if a fat mass is generated, the fat mass can be discharged, and blockage in the fermenter due to fat particles can be suppressed, and deterioration of fermentation can be suppressed.

The oil component treatment step can cut or crush the oil component extracted from the fermenter. According to this structure, generation | occurrence | production of the lump of an oil component can be prevented within a fermenter.

In the oil treatment step, the oil extracted from the fermenter can be solubilized. According to this structure, generation | occurrence | production of the lump of an oil component can be prevented within a fermenter.

  In the charging step, the oil component processed in the oil component processing step is charged to at least one of the heating device provided in the circulation path and the outlet of the heating device. According to this configuration, since the temperature of the circulating fermentation broth is high in the vicinity of the heating device, the oil component processed by the oil component processing device can be further solubilized.

  ADVANTAGE OF THE INVENTION According to this invention, even when the fat lump generate | occur | produces, the obstruction | occlusion in the fermenter by a fat granule can be suppressed, and the methane fermentation processing apparatus and the methane fermentation processing method which can suppress the deterioration of fermentation can be provided.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a methane fermentation treatment apparatus according to an embodiment of the present invention. As shown in FIG. 1, a methane fermentation treatment apparatus 1 includes an organic waste storage tank 2, a slurry supply pump 3, a methane fermentation tank 4, a fermentation liquid circulation line (circulation path) 5, a fermentation liquid circulation pump 6, and a heating device. 7, Fermentation liquid drawing pump 8, oil content processing line 9, floating oil content drawing pump 10, and floating oil content processing device 11 are provided.

  The methane fermentation treatment apparatus 1 collects resources such as biogas mainly containing methane gas by supplying organic waste such as garbage. The organic waste storage tank 2 stores slurry in which organic waste is adjusted to a predetermined concentration with tap water or the like. The slurry supply pump 3 supplies the organic waste stored and slurried in the organic waste storage tank 2 to the methane fermentation tank 4.

  The methane fermentation tank 4 generates biogas mainly composed of methane gas from organic waste. The methane fermentation tank 4 is provided with a fixed filter bed filled with immobilized microorganisms on which anaerobic microorganisms such as methane bacteria are attached and supported. Biogas produced by fermentation is used as energy in gas utilization systems such as gas turbines and fuel cells.

  The fermentation liquor circulation line 5 is a path for heating the fermentation liquor extracted from the methane fermentation tank 4 to the outside and returning it to the methane fermentation tank 4 with the heating device 7. The fermentation liquor circulation pump 6 extracts the fermentation liquor in the methane fermentation tank 4 and transfers the fermentation liquor into the fermentation liquor circulation line 5 that is heated by the heating device 7. The heating device 7 warms the fermentation broth in the fermentation broth circulation line 5. The fermentation liquid drawing pump 8 supplies the fermentation waste liquid in the methane fermentation tank 4 to a waste liquid treatment tank (not shown).

  The oil content treatment line 9 is a path for feeding the floating oil content accumulated in the methane fermentation tank 6 into the fermentation liquor circulation line 5. This oil component treatment line 9 is connected to the fermentation liquor circulation line 5 before the introduction of the heating device 7 or near the outlet of the heating device 7, and returns the oil component treated by the floating oil component treatment device 11 to the fermentation liquor circulation line 5. Can do. The floating oil fraction extraction pump 10 extracts the accumulated and floated oil in the methane fermentation tank 4 and supplies it to the floating oil processing device 11.

  The floating oil content processing device 11 performs lump prevention processing on the oil content extracted from the methane fermentation tank 4. For example, the floating oil content processing apparatus 11 applies physical cutting or crushing to the oil extracted from the methane fermentation tank 4 by a cutter mixer, a pulverization pump, ultrasonic irradiation, or the like, or heating or microwaves. Is solubilized by heat.

  When the floating oil component processing apparatus 11 is configured by, for example, a cutter mixer or a pulverizing pump, the oil component extracted from the methane fermentation tank 4 can be redispersed by the cutter mixer, the pulverizing pump, or the like. Moreover, when the floating oil component processing apparatus 11 is comprised by a heater, for example, the oil component extracted from the inside of the methane fermentation tank 4 can be melt | dissolved at temperature more than predetermined (for example, 80 degreeC or more). Moreover, when the floating oil component processing apparatus 11 is comprised with the apparatus which can irradiate a microwave, it can be made to melt | dissolve by irradiating a microwave with respect to the oil extracted from the methane fermentation tank 4. FIG.

  Moreover, when the floating oil component processing apparatus 11 is comprised with the apparatus which can be solubilized by the high-temperature / high pressure hydrothermal reaction, the oil component extracted from the inside of the methane fermentation tank 4 can be solubilized by a hydrothermal reaction. Furthermore, when the floating oil component processing device 11 is configured by a device that emits ultrasonic waves, the oil component extracted from the methane fermentation tank 4 can be redispersed by ultrasonic dispersion.

  Examples of the present invention will be described below. First, Examples 1 to 4 of the present invention will be described. Examples 1 to 4 are examples in which ice cream is used as a sample.

  As an organic substance having a high saturated fatty acid ratio, ice cream was used as a material, diluted twice with tap water, and adjusted with a cutter mixer for a cafeteria was used as a raw material slurry. Table 1 shows the composition of the ice cream slurry prepared.

発酵条件は、メタン発酵槽４としては発酵容積５リットルの完全混合槽で発酵温度５５℃、滞留時間(ＨＲＴ)１０日で行なった。

As the methane fermentation tank 4, the fermentation conditions were a complete mixing tank with a fermentation volume of 5 liters, a fermentation temperature of 55 ° C., and a residence time (HRT) of 10 days.

  The volume of the organic waste storage tank 2 storing the ice cream slurry was 5 liters, and the experiment was performed while stirring at a predetermined stirring intensity at room temperature. The sample was introduced into the fermentation liquor circulation line 5 in a predetermined amount of ice cream slurry by dividing into 12 parts per day. The floated oil substance is sucked and discharged from the methane fermentation tank 4 once a day by the float oil extraction pump 10, and is solubilized by the float oil treatment apparatus 11 as in the following examples. Combined with the circulation line 5. Moreover, the methane fermentation tank 4 was filtered with a mesh filter, and the oil content on the mesh was weighed, and the accumulation tendency of the oil content was comparatively evaluated.

Comparative Example 1
It operated for 10 days, without discharging the floating oil substance generated in the methane fermentation tank 4.

Example 1
The oily substance floating in the methane fermentation tank 4 is extracted by a floating oil extractor pump 10, diluted 5 times, and then pulverized and redispersed for about 2 minutes by a cutter mixer as the floating oil processing unit 11. 5 and mixed for 10 days.

Example 2
The oily substance floating in the methane fermentation tank 4 is extracted by a floating oil extractor pump 10 and melted by irradiating microwaves for about 2 minutes in a microwave oven as the floating oil component treatment device 11 and then mixed in the fermentation liquid circulation line 5. And operated for 10 days.

Example 3
The oily substance floating in the methane fermentation tank 4 is extracted by a floating oil extractor pump 10, solubilized by a high temperature and high pressure hydrothermal reaction by the floating oil component treatment device 11, mixed with the fermentation liquor circulation line 5, and operated for 10 days. .

Example 4
The oily substance floating in the methane fermentation tank 4 was extracted with a floating oil extractor pump 10 and irradiated with ultrasonic waves for 15 minutes by the floating oil component treatment device 11, mixed with the fermentation liquor circulation line 5, and operated for 10 days.
Table 2 shows a comparison of the oil accumulation amount.

これらの結果より、メタン発酵槽４内に発生した例えば脂肪粒などの浮上油分を浮上油分処理装置１１で油分の塊の発生防止処理を行ない、再度、可溶化もしくは分散して、メタン発酵槽４の外部に引き抜き加温して戻す発酵液循環ライン５中に投入することで、メタン発酵槽４での油分の塊の発生を防止できるのが分かる。

From these results, the floating oil component such as fat particles generated in the methane fermentation tank 4 is subjected to a treatment for preventing the formation of a lump of oil with the floating oil processing unit 11 and is solubilized or dispersed again. It turns out that generation | occurrence | production of the lump of the oil component in the methane fermentation tank 4 can be prevented by throwing in the fermentation liquid circulation line 5 which draws out outside and heats and returns.

発酵条件は、メタン発酵槽４が発酵容積５リットルの完全混合槽で発酵温度５５℃、滞留時間(ＨＲＴ)１０日で行なった。試料の投入は１日１２分割で所定量を投入した。浮上した油分物質は、浮上油分引き抜きポンプ１０によって１日１回、メタン発酵槽４外へ吸引して排出し、以下の実施例のように浮上油分処理装置１１によって可溶化処理を行ない、発酵液循環ライン５に合流させた。また、メタン発酵槽４をメシュフィルターでろ過し、メッシュに残った油分を秤量して、油分の蓄積傾向を比較評価した。 Next, Examples 5 to 9 of the present invention will be described. In Examples 5 to 9, olive oil waste liquid, salad oil waste liquid, ice cream waste liquid, garbage diluted waste liquid 1 and garbage diluted waste liquid 2 are used as samples. Table 3 shows the composition of the sample used in the experiment. The concentration of a predetermined organic waste liquid was adjusted with water and used for a fermentation experiment.

Fermentation conditions were performed in a methane fermentation tank 4 having a fermentation volume of 5 liters and a fermentation temperature of 55 ° C. and a residence time (HRT) of 10 days. The sample was charged in a predetermined amount in 12 divisions per day. The floated oil substance is sucked and discharged from the methane fermentation tank 4 once a day by the float oil extraction pump 10, and is solubilized by the float oil treatment apparatus 11 as in the following examples. Combined with the circulation line 5. Moreover, the methane fermentation tank 4 was filtered with a mesh filter, the oil content remaining on the mesh was weighed, and the accumulation tendency of the oil content was comparatively evaluated.

Example 5
The ice cream waste liquid of sample 3 is put into the methane fermentation tank 4, and the oily substance floating in the methane fermentation tank 4 is extracted with the floating oil extraction pump 10, and pulverized for about 2 minutes with a cutter mixer, and then the fermentation liquid circulation line 5 And operated for 10 days.

Example 6
The waste diluted waste liquid 1 of the sample 4 is put into the methane fermentation tank 4, and the oily substance floating in the methane fermentation tank 4 is extracted by the floating oil extraction pump 10, and pulverized for about 2 minutes by the cutter mixer, and then the fermentation liquid circulation It was joined to line 5 and operated for 10 days.

Example 7
The waste diluted waste liquid 2 of the sample 5 is put into the methane fermentation tank 4, and the oily substance floating in the methane fermentation tank 4 is extracted with a floating oil extraction pump 10, pulverized for about 2 minutes with a cutter mixer, and then fermented liquid circulation It was joined to line 5 and operated for 10 days.

Example 8
The ice cream waste liquid of sample 3 is put into the methane fermentation tank 4, and the oily substance floating in the methane fermentation tank 4 is extracted by the floating oil extractor pump 10, and irradiated with ultrasonic waves by the floating oil component treatment device 11 for 15 minutes, and then fermented. The mixture was mixed in the liquid circulation line 5 and operated for 10 days.

Example 9
The ice cream waste liquid of sample 3 is put into the methane fermentation tank 4, and the oily substance floating in the methane fermentation tank 4 is extracted by the floating oil extraction pump 10, and the microwave is used for about 2 minutes in the microwave as the floating oil content processing device 11. After irradiation, the mixture was mixed in the fermented liquid circulation line 5 and operated for 10 days.

Comparative Example 2
The olive oil waste liquid of Sample 1 was put into the methane fermentation tank 4 and operated for 10 days.

Comparative Example 3
The salad oil waste liquid of sample 2 was put into the methane fermentation tank 4 and operated for 10 days.

Comparative Example 4
The ice cream waste liquid of Sample 3 was put into the methane fermentation tank 4 and operated for 10 days.

Comparative Example 5
The waste diluted waste liquid 2 of the sample 5 was put into the methane fermentation tank 4 and operated for 10 days.

  Table 4 shows a comparison of the oil accumulation amount.

アイスクリーム廃液を用いて、油分塊防止処理と発酵液循環ライン５への返送を行なわないで発酵した場合（比較例４）、油脂の粒が発酵液に蓄積した。

When the ice cream waste liquid was used for fermentation without performing the oil lump prevention treatment and the return to the fermentation liquid circulation line 5 (Comparative Example 4), fat and oil particles accumulated in the fermentation liquid.

  In the case where fermentation was performed without using the raw waste diluted waste liquid and the return to the fermentation liquid circulation line 5 (Comparative Example 5), fat and oil particles accumulated in the fermentation liquid.

  When using olive oil (Comparative Example 2) or salad oil (Comparative Example 3) and fermenting without performing oil mass block treatment and returning to the fermented liquid circulation line 5, the fat and oil particles did not accumulate in the fermented liquid.

  When the ice cream waste liquid is pulverized by a cutter mixer (Example 5), subjected to ultrasonic irradiation (Example 6), or microwave irradiation (Example 9) and returned to the fermentation liquid circulation line 7, The accumulation of grains was small.

  When grind | pulverizing by the cutter mixer (Examples 6 and 7) using the garbage waste liquids 1 and 2 and returning to the fermenter circulation line 5, there was little accumulation of fat and oil particles.

From these results, the floating oil component generated in the methane fermentation tank 4 is subjected to the oil mass block prevention treatment again using the above-described method, and is introduced into the fermentation liquor circulation line 5. It turns out that generation | occurrence | production of the lump of oil can be prevented.
In addition, as conditions under which fat particles are likely to be generated, the properties of the organic waste sample at that time are as follows: the content of palmitic acid and stearic acid is 40% or more of the total fatty acids, and the concentration of n-hexane extract is 2 g / L. It was confirmed that this was the case.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications may be made within the scope of the gist of the present invention described in the claims. It can be changed.

It is a block diagram of the methane fermentation processing apparatus which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Methane fermentation processing apparatus 2 ... Organic waste storage tank 3 ... Slurry supply pump 4 ... Methane fermentation tank 5 ... Fermentation liquid circulation line 6 ... Fermentation liquid circulation pump 7. ..Heating device 8 ... fermentation liquid extraction pump 9 ... oil content processing line 10 ... floating sludge extraction pump 11 ... oil content processing device

Claims (13)

A methane fermentation treatment apparatus having a fermenter for methane fermentation of organic waste,
A circulation path for warming the fermentation liquor drawn from the fermentation liquor withdrawal port disposed in the vicinity of the bottom of the fermenter and returning it to the vicinity of the upper portion of the fermenter;
Processing to prevent oil mass from being generated by extracting oil from the oil extraction port of the fermenter provided at a horizontal position above the fermentation liquid extraction port and substantially corresponding to the outlet of the circulation path. An oil content processing apparatus,
An oil content treatment path for introducing the oil content treated by the oil content treatment device into the circulation path;
A methane fermentation treatment apparatus comprising: The oil processing unit, the methane fermentation treatment apparatus according to claim 1, wherein the fermented oil cutting or crushing that withdrawn from tank, it is characterized. 2. The methane fermentation treatment apparatus according to claim 1 , wherein the oil content processing apparatus melts the oil extracted from the fermenter at a temperature of 80 ° C. or more. The oil processing unit, the methane fermentation treatment apparatus according to claim 1, wherein the oil component withdrawn from the fermentor using microwave radiation to melt, it is characterized. The oil processing unit, the methane fermentation treatment apparatus according to claim 1, wherein the oil content was withdrawn from the fermentation tank to solubilize hydrothermal reaction, characterized in that. The oil processing unit, the methane fermentation treatment apparatus according to claim 1, wherein the oil content was withdrawn from the fermenter is dispersed ultrasonically be characterized. The oil processing path, either the is connected to at least one of the outlets before and the heating device introduction of a heating device provided in the circulation path, from claim 1, characterized in that the claims 6 The methane fermentation processing apparatus of crab. The n-hexane extract substance concentration of the organic waste is 2 g / L or more, and the methane fermentation treatment apparatus according to any one of claims 1 to 7 . The methane fermentation treatment apparatus according to any one of claims 1 to 8 , wherein a content ratio of palmitic acid and stearic acid in the organic waste is 40% or more of all fatty acids. A fermenter for methane fermentation of organic waste, and a circulation path for heating the fermented liquor extracted from the fermented liquid extraction port disposed near the bottom of the fermenter and returning it to the vicinity of the upper part of the fermenter. A methane fermentation treatment method using a methane fermentation treatment apparatus,
A step of extracting oil from the oil extraction port of the fermenter provided at a horizontal position above the fermentation liquid extraction port and substantially corresponding to the outlet of the circulation path ;
An oil treatment step for performing a treatment for preventing the formation of the lump of oil to the oil; and
A charging step of charging the oil component processed in the oil component processing step into the circulation path;
A methane fermentation treatment method characterized by comprising: The said oil content processing process cut | disconnects or crushes the oil extracted from the said fermenter, The methane fermentation processing method of Claim 10 characterized by the above-mentioned. The methane fermentation treatment method according to claim 10 , wherein the oil content treatment step solubilizes the oil content extracted from the fermenter. The oil adding process is characterized in that, in the charging step, the oil component processed in the oil component processing step is charged into at least one of the heating device provided in the circulation path and the outlet of the heating device. The methane fermentation treatment method according to any one of claims 10 to 12 .

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