JP2007319725A - Methane fermentation plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a methane fermentation plant in which sand is not be precipitated/accumulated at the bottom of a methane fermentation tank, which is made simple and inexpensive and the treatment efficiency of which is made high. <P>SOLUTION: The methane fermentation plant is characterized in that at least one pump 9 is used and the courses of fluids flowing through a motor-driven switching valve 10 are changed when a squeezed liquid B is introduced into the methane fermentation tank 6 from a squeezed liquid tank 3, when a liquid D withdrawn from the methane fermentation tank is returned to the methane fermentation tank, when the liquid D withdrawn from the methane fermentation tank is supplied to a sand separator 7 and a sand-removed liquid is returned to the methane fermentation tank, when the liquid D withdrawn from the methane fermentation tank is supplied to a gas inspirator 8 and a gas-removed liquid is returned to the methane fermentation tank, and when a digested liquid E withdrawn from the methane fermentation tank is transferred to a digested liquid tank 11. The methane fermentation plant is made simple and inexpensive by adopting the sand separator 7 for removing sand, a balloon-type gas holder 4, a simplified building 5 and the squeezed liquid tank 3 and the methane fermentation tank 6 both of which are formed by using prefabricated concrete retaining walls 3a, 6a and watertight sheets 3b, 3a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a methane fermentation treatment plant that is simple and low-cost and has high treatment efficiency.

  In recent years, biogas obtained by methane fermentation of high-concentration organic wastewater such as livestock manure and food residues has attracted attention as energy friendly to the global environment.

  As an apparatus for performing such methane fermentation, for example, a fermentation tank for methane fermentation of introduced livestock manure, etc., and a water drainer that introduces a gas generated in the fermentation tank and removes water contained in the gas. A methane comprising a tank, a desulfurization tank for further removing hydrogen sulfide from the gas from which moisture has been removed, and a blower for introducing the gas derived from the desulfurization tank to the gas tank and supplying the gas into the fermentation tank as a stirring gas A fermentation apparatus is known (Patent Document 1).

In addition, after one of the present applicants efficiently fermented methane fermentation of a solution obtained by deproteinizing blood juice and boiled juice discharged in the fishery processing process (Patent Document 2), or after alcohol fermentation with yeast. Have already filed and patented a method for efficiently fermenting a waste liquid of methane (Patent Document 3) and a method for efficiently fermenting a liquid obtained by diluting tofu cake with water (Patent Document 4).
Japanese Utility Model Publication No. 60-24396 JP-A 63-185499 JP-A 64-474498 JP-A-2-187199

  The above methane fermentation methods of Patent Documents 2, 3, and 4 are carried out without such inconvenience, and greatly contribute to the reuse of wastes discharged from fishery processors, brewers, tofu manufacturers, etc. as energy sources. Yes.

  However, since the raw material contains a large amount of sand, as in the methane fermentation method of Patent Document 1 described above, a large amount of sand is deposited in the bottom of the methane fermentation tank. become. Therefore, it is necessary to remove this sand. However, since this sand removal work is quite troublesome and time-consuming, it may take about 1 to 3 months for the sand removal work in a large methane fermentation tank. In the meantime, since the apparatus must be stopped, there is a problem that the operating rate is greatly reduced.

  In addition, in order to increase the profits by increasing the income of biogas obtained by methane fermentation rather than the equipment costs and maintenance costs required for methane fermentation, make the equipment as simple and low-cost as possible with high processing efficiency. However, since the conventional methane fermentation treatment equipment is neither a simple low cost type nor a high treatment efficiency, there is also a problem that it is difficult to obtain an economic balance.

  The present invention has been made under the circumstances described above, and as a problem to be solved, it is possible to provide a methane fermentation treatment plant that does not deposit sand on the bottom of a methane fermentation tank and that is simple, low-cost and high in processing efficiency. Yes.

  In order to solve the above-mentioned problems, the methane fermentation treatment plant according to the present invention introduces the juice from the juice tank and the juice tank that temporarily stores the juice separated from the organic waste such as livestock manure. The methane fermentation tank for methane fermentation, the gas holder for temporarily storing the gas generated in the methane fermentation tank, and the sand contained in this liquid before returning the liquid extracted from the methane fermentation tank to the methane fermentation tank A gas separator that separates the liquid extracted from the methane fermentation tank, a gas inhaler that inhales the gas supplied from the methane fermentation tank to the liquid before returning it to the methane fermentation tank, and a digestion extracted from the methane fermentation tank At least a digestive bath for temporarily storing the liquid, and at least one pump and an electric switching valve installed in the pipeline connecting them, and at least one by switching the electric switching valve The pump introduces the juice into the methane fermentation tank, returns the liquid extracted from the methane fermentation tank to the methane fermentation tank, supplies the liquid extracted from the methane fermentation tank to the sand separator and separates the sand. Of the recovered liquid to the methane fermentation tank, supply of the liquid extracted from the methane fermentation tank to the gas inhaler, return of the liquid sucked in the gas to the methane fermentation tank, and digestive liquid tank of the digested liquid extracted from the methane fermentation tank It is characterized in that it is transferred to.

  In the methane fermentation treatment plant of the present invention, the gas holder is a balloon-shaped gas holder made of an airtight sheet, and the balloon-shaped gas holder is installed on the top plate of the methane fermentation tank and formed on the top plate. It is preferable to connect the balloon-shaped gas holder and the methane fermentation tank through the vent. And it is preferable to attach a water remover to this vent hole. Further, it is preferable that the gas holder is housed in a simple building constructed with aggregate and tent cloth, and the upper end of the gas holder is attached to the upper part of the simple building.

  Moreover, in the methane fermentation processing plant of this invention, the nonwoven fabric which carried | supported the anaerobic sludge was attached inside the methane fermentation tank, and the density | concentration of the anaerobic sludge with respect to the liquid in a methane fermentation tank was maintained at 4 +/- 1 mass%. It is preferable to make it. And forming each tank bottom of a methane fermentation tank, squeezed liquid tank, digestive liquid tank with a watertight sheet, forming each side wall of a methane fermentation tank, squeezed liquid tank with a ready-made concrete retaining wall, methane It is preferable to attach a heat insulating material to the outer surface of the side walls of the fermentation tank and squeezed liquid tank. Furthermore, heat exchangers are attached to the inside of each of the methane fermentation tank and squeezed liquid tank, and hot water heated by burning the dehumidified and purified gas extracted from the gas holder is supplied to the respective heat exchangers. It is preferable to keep the liquid temperature at 36 ± 5 ° C. and the liquid temperature in the squeezed liquid tank at 50 ± 5 ° C.

  The methane fermentation treatment plant of the present invention is a methane fermentation tank of the liquid extracted from the methane fermentation tank by introducing the juice from the squeezed liquid tank to the methane fermentation tank with a minimum of one pump by switching the electric switching valve. Return to the methane fermentation tank, supply the liquid extracted from the methane fermentation tank to the sand separator, return the liquid separated from the sand to the methane fermentation tank, supply the liquid extracted from the methane fermentation tank to the gas inhaler and inhale the gas Since the returned liquid is returned to the methane fermentation tank and the digested liquid extracted from the methane fermentation tank is transferred to the digestive liquid tank, the number of equipment (in comparison with a conventional methane fermentation apparatus that uses several pumps) The number of pumps) can be reduced, and the cost can be reduced. Then, the liquid extracted from the methane fermentation tank with this minimum one pump is supplied to the sand separator to separate the sand, and the liquid separated and removed from the sand is returned to the methane fermentation tank. There is no worry of sand depositing on the bottom. Therefore, it is not necessary to stop the apparatus for a considerably long period of time to remove sand as in the conventional methane fermentation apparatus, so that the operating rate can be greatly improved.

  In addition, the methane fermentation treatment plant of the present invention supplies a liquid extracted from the methane fermentation tank with a minimum of one pump to a gas inhaler, and inhales the gas supplied from the methane fermentation tank to the liquid methane fermentation. By returning to the tank, the liquid in the methane fermentation tank can be gas stirred. And if the liquid extracted from the methane fermentation tank with a minimum of one pump is returned to the methane fermentation tank without supplying it to the gas inhaler, the liquid in the methane fermentation tank can be agitated by the returned liquid.

  Furthermore, a balloon-shaped gas holder made of an airtight sheet is installed on the top plate of the methane fermentation tank, and the balloon-shaped gas holder and the methane fermentation tank are communicated with each other through a vent formed in the top plate. Compared with a conventional gas gas tank installed in a place different from the methane fermentation tank, the equipment content is much simpler and the cost and installation space can be reduced. And what attached the dehydrator to said vent hole can store the gas from which most of water | moisture content was removed in a gas holder, Therefore It can prevent that a water droplet adheres to the inner wall of a gas holder. In addition, a gas holder is housed inside a simple building constructed of aggregate and tent cloth, and the upper end of the gas holder is attached to the upper part of this simple building, so that a simple building made of aggregate and tent cloth is inexpensive. Further, there is an advantage that the gas holder can be protected by this simple house.

  In addition, a sludge-attached cloth with anaerobic sludge attached to the inside of the methane fermentation tank and the concentration of the anaerobic sludge with respect to the liquid in the methane fermentation tank maintained at 4 ± 1% by mass is anaerobic. Since the sludge concentration is much higher than the anaerobic sludge concentration in the conventional methane fermentation tank, coupled with the fact that the liquid temperature of the methane fermentation tank is kept at 36 ± 5 ° C. as described later, Methane fermentation becomes very active, and it becomes possible to obtain a gas in which methane gas occupies 70 to 80%.

  And what formed each tank bottom of a methane fermentation tank, squeezed liquid tank, digestive liquid tank with a water-tight sheet, and what formed each side wall of a methane fermentation tank and squeezed liquid tank with a ready-made concrete retaining wall Because the construction of each tank is simple and the material cost is low, the equipment cost can be reduced. Also, the heat insulation material attached to the outer surface of the side wall of the methane fermentation tank and squeezed liquid tank has little heat dissipation. Therefore, there is an advantage that the amount of heat required for heat insulation can be greatly saved, which is economical. Furthermore, heat exchangers are attached to the inside of each of the methane fermentation tank and squeezed liquid tank, and hot water heated by burning the dehumidified and purified gas extracted from the gas holder is supplied to the respective heat exchangers. The liquid temperature of 36 ± 5 ° C. and the temperature of the squeezed liquid tank kept at 50 ± 5 ° C. are extracted from the gas holder, dehumidified, and the methane fermentation tank and squeezed liquid tank are kept warm by using dehumidified and purified gas as fuel Therefore, it is not necessary to purchase fuel from the outside, and by keeping the methane fermentation tank at 36 ± 5 ° C., a gas having a high methane gas concentration can be obtained as described above.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic explanatory view of a main part of a methane fermentation treatment plant according to an embodiment of the present invention, FIG. 2 is a schematic explanatory view of a gas purification part of the methane fermentation treatment plant, and FIGS. 3 and 4 are balloon-type gas holders. And a schematic sectional view and a schematic plan view of a methane fermentation tank provided with a simple building on a top plate, and FIG. 5 is a perspective view of a sludge-attached cloth.

  As shown in FIG. 1, the main part of this methane fermentation treatment plant consists of a receiving tank 1, a squeezed liquid tank 3 in which a solid-liquid separator 2 is installed on a top plate, a balloon-shaped gas holder 4 and a simple building 5. A methane fermentation tank 6, a sand separator 7, a gas inhaler 8, a pump 9, an electric switching valve 10, a digestive liquid tank 11, and the like installed on a plate are provided.

  In the receiving tank 1, organic waste A such as livestock excreta that has been transported is temporarily stored. As the organic waste A, livestock manure such as swine manure, cattle manure, and a mixture thereof is used, and a mixture of these livestock manure and shochu waste liquid or the like is also used.

  The organic waste A in the receiving tank 1 is supplied to the solid-liquid separator 2 through the line L1 by the pump in the receiving tank, and the excess organic waste A passes through the lines L2 and L3. Returned to the receiving tank 1. The organic waste A supplied to the solid-liquid separator 2 is squeezed, and the squeezed liquid B is temporarily stored in the squeezed liquid tank 3. The solid residue C discharged from the solid-liquid separator 2 is composted and effectively used as compost.

  A heat exchanger 12 is attached to the inside of the squeezed liquid tank 3, and the temperature of the squeezed liquid B is kept at 50 ± 5 ° C. by the hot water supplied and circulated from the hot water storage tank 25 described later through the pipes L4 and L5. Has been. This squeezed liquid tank 3 is installed on the ground to facilitate the supply of the squeezed liquid to the methane fermentation tank 6. And in order to simplify and reduce the cost of the tank, the side wall is formed with a ready-made concrete retaining wall 3a such as a box culvert, and the tank bottom is formed with a strong watertight sheet 3b such as a main bran, Further, in order to increase the heat insulation efficiency, a heat insulation material (not shown) is attached to the outer surface of the side wall.

  The methane fermentation tank 6 into which the squeezed liquid B is introduced from the squeezed liquid tank 3 through the pipes L6 and L7 is embedded in the ground so that the liquid level inside thereof is lower than the bottom surface of the squeezed liquid tank 3. Inside, a sludge-attached cloth 13 to which anaerobic sludge is attached and a heat exchanger 14 are attached. And in the heat exchanger 14 of this methane fermentation tank 6, the hot water which passed through the heat exchanger 12 of the said squeeze liquor tank 3 and fell a little is supplied and circulated through the pipe line L8, and a methane fermentation tank The liquid temperature of 6 is kept at 36 ± 5 ° C.

  As shown in FIG. 5, the sludge attachment cloth 13 attached to the inside of the methane fermentation tank 6 is made by attaching anaerobic sludge containing methane bacteria to a vertically long oval non-woven fabric. A plurality of sludge adhering cloths 13 are respectively hooked and attached in parallel to the plurality of upper and lower two support rods 13b, 13b provided in a protruding manner. The anaerobic sludge of this sludge adhesion cloth 13 is 4 ± 1 mass with respect to the liquid D in the methane fermentation tank 6 by adjusting the time for gas stirring the liquid D in the methane fermentation tank 6 as described later. % Concentration is maintained. The anaerobic sludge concentration of 4 ± 1% by mass is extremely high compared to the anaerobic sludge concentration in the conventional methane fermentation tank, and the liquid temperature in the methane fermentation tank 6 is kept at 36 ± 5 ° C. as described above. In combination with this, methane fermentation becomes extremely active. Therefore, this methane fermentation tank 6 generates digestion gas in which methane gas occupies 70 to 80%, and far more than that which generates digestion gas in which methane gas occupies 50 to 65% as in the conventional methane fermentation tank. High energy digestion gas can be obtained.

  In order to simplify and reduce the cost of the tank, the methane fermentation tank 6 is formed with a ready-made concrete retaining wall 6a such as a box culvert as shown in FIG. The water-tight sheet 6b. And in order to improve heat insulation efficiency, the heat insulating material 6c is attached to the outer surface of the concrete retaining wall 6a. Moreover, the top plate 6d of the methane fermentation tank 6 is made of resin concrete, and as shown in FIGS. 3 and 4, it is formed in a square plate shape that is slightly larger than the opening area of the methane fermentation tank 6, A cloth base portion 6e is integrally formed on the four peripheral edges. The top plate 6d is placed on the upper end of the side wall 6a of the methane fermentation tank 6 and exposed to the ground. However, the cloth base portion 6e at the four peripheral edges of the top plate 6d is buried in the ground to support the load. Therefore, there is no worry that a large load is applied to the upper end of the side wall 6a of the methane fermentation tank 6.

  On the top plate 6 d of the methane fermentation tank 6, a balloon-type gas holder 4 and a simple building 5 that houses the gas holder 4 are installed. The balloon-shaped gas holder 4 is made of an airtight sheet, and the lower end of the opening is airtightly fixed to the top plate 6d of the methane fermentation tank 6, and the vent 6f formed in the top plate 6d is connected to the top plate 6d. And communicated with the methane fermentation tank 6. A SUS wire mesh demister 15 is attached to the vent 6f as a dewatering device. Since most of the water contained in the digestion gas is removed as water droplets by the demister 15, digestion with a low water content is performed. The gas is stored in the gas holder 4. Therefore, water droplets do not adhere to the inner surface of the balloon-type gas holder 4 due to condensation or the like. Moreover, since this balloon-shaped gas holder 4 is suspended with its upper end fixed to the beam at the top of the simple building 5, even if the gas holder 4 is deflated as shown by a chain line in FIG. It will not fall on the top plate 6d.

  The above-mentioned simple building 5 installed on the top plate 6d of the methane fermentation tank 6 is a tent cloth in which a skeleton is assembled using an aggregate 5a such as a metal pipe to be a pillar or a beam, and the skeleton is processed with fluorine. The simple building 5 is provided with an entrance door 5c shown in FIG. 4 and a ventilation louver 5d shown in FIG. When such a simple building 5 is constructed and the balloon-type gas holder 4 is accommodated, there is an advantage that the balloon-type gas holder 4 can be protected from being damaged by flying objects or the like. In addition, as shown in FIGS. 3 and 4, it is desirable to provide a manhole type inspection port 5 e with a transparent lid through which the inside of the methane fermentation tank 6 can be seen in the top plate 6 d inside the simple building 5. .

  When the balloon-shaped gas holder 4 and the simple building 5 are installed on the top plate 6d of the methane fermentation tank 6 as described above, and the gas holder 4 and the methane fermentation tank 6 are communicated with each other through the vent 6f, a metal like the conventional one is used. Since it is not necessary to install the gas tank in a different place from the methane fermentation tank, the facilities are simplified, and it is possible to reduce costs and installation space.

  As shown in FIG. 1, a single pump 9 and an electric switching valve 10 are installed between pipes L <b> 6 and L <b> 7 for introducing the juice B from the bottom of the juice tank 3 to the bottom of the methane fermentation tank 6. ing. The electric switching valve 10 is provided with four outlets, and the four outlets are connected to the methane fermentation tank via the pipe L7 leading to the bottom of the methane fermentation tank 6 and the sand separator 7. A pipe L9 that joins the pipe L7 that leads to the pipe, a pipe L10 that joins the pipe L7 that leads to the methane fermentation tank via the gas inhaler 8, and a pipe L11 that leads to the digestion tank 11 are connected to each other. ing. And the pipe L12 which joins from the bottom part of the methane fermentation tank 6 to the pipe line L6 of the upstream of the said pump 9 is provided, and the pipe for gas supply which leads to said gas inhaler 8 from the upper part of the methane fermentation tank 6 A path L13 is provided.

  As the sand separator 7, a cyclone type having high separation efficiency is preferably used, and as the gas inhaler 8, an ejector type having high suction efficiency is preferably used. And as the digestive-solution tank 11, while forming the side wall with the waterproof block 11a, the simple tank which formed the tank bottom with the water-tight sheet | seat 11b is employ | adopted preferably.

  Next, a series of processing operations for methane fermentation will be described.

  In order to continue the methane fermentation treatment from the state shown in FIG. 1, first, the electric switching valve 10 is switched to connect the pipe L6 and the pipe L11, and the pump 9 is operated to liquid in the methane fermentation tank 6. A predetermined amount of D (digestion fluid) is extracted and transferred to the digestive fluid tank 11 through the pipeline L12, the pipeline L6, and the pipeline L11. The transfer to the digestive fluid tank 11 may be performed once a day. The digestive fluid E transferred to the digestive fluid tank 11 is used as liquid fertilizer.

  When the transfer to the digestive liquid tank 11 is finished, the electric switching valve 10 is switched to connect the squeezed liquid introduction pipe L6 and the pipe L7, and the pump 9 is operated to squeeze from the bottom of the squeezed liquid tank 3. The sap B is introduced into the methane fermentation tank 6 through the lines L6 and L7, and the deficiency of the liquid D in the methane fermentation tank 6 is replenished. The juice B may be introduced into the methane fermentation tank 6 once a day.

  The squeezed liquid introduced into the methane fermentation tank 6 contains fine sand that could not be removed by the solid-liquid separator 2. Therefore, the electric switching valve 10 is switched to connect the pipe L6 and the pipe L9, and the pump 9 is operated so that the liquid D containing sand at the bottom of the methane fermentation tank 6 is supplied to the pipe L12, the pipe L6, The liquid supplied to the sand separator 7 through the pipe line L9 is efficiently returned to the bottom of the methane fermentation tank 6 through the pipe line L9 and the pipe line L7. This sand separation and removal may be performed once a day for several minutes. If the sand is separated and removed in this way, the problem of sand being deposited on the bottom of the methane fermentation tank 6 can be solved.

  Moreover, in order to perform methane fermentation actively, while stirring the liquid D in the methane fermentation tank 6, the contact frequency with the anaerobic sludge adhering to the sludge adhesion cloth 13 is raised, and the density | concentration of anaerobic sludge is mentioned above. Thus, it is important to maintain 4 ± 1%. Therefore, the electric switching valve 10 is switched to connect the pipe L6 and the pipe L10, and the pump 9 is operated so that the liquid D in the methane fermentation tank 6 is ejected through the pipe L12, the pipe L6, and the pipe L10. The gas is supplied to the gas inhaler 8 of the system, the gas supplied from the upper space of the methane fermentation tank 6 through the pipe L13 is sucked, and this gas and liquid are returned to the bottom of the methane fermentation tank 6 through the pipe L7. It discharges from the front-end | tip of the pipe line L7. Thereby, the liquid D in the methane fermentation tank 6 is subjected to gas agitation with the gas released from the pipe L7 and liquid agitation with the liquid released from the pipe L7. This stirring is preferably performed for about 15 minutes every 2 hours. Moreover, the electric switching valve 10 is switched to connect the pipe L6 and the pipe L7, the pump 9 is operated, and the liquid D extracted from the methane fermentation tank 6 is methane through the pipe L12, the pipe L6, and the pipe L7. By returning to the fermentation tank 6, the liquid D in the methane fermentation tank 6 may be subjected only to liquid stirring.

  The above switching operation of the electric switching valve 10 is all performed by automatic control.

  As described above, by switching the electric switching valve 10, methane fermentation of the liquid D extracted from the methane fermentation tank 6 by introducing the juice B from the squeezed liquid tank 3 to the methane fermentation tank 6 with a single pump 9. Liquid agitation by returning to the tank 6, supply of the liquid D extracted from the methane fermentation tank 6 to the sand separator 7, return of the liquid separated from the sand to the methane fermentation tank 6, and liquid D extracted from the methane fermentation tank 6 The gas inhaler 8 is supplied to the methane fermentation tank 6 and the gas D and the liquid agitation are all returned to the methane fermentation tank 6. The digestion liquid E extracted from the methane fermentation tank 6 is transferred to the digestion liquid tank 11. Since it performs, compared with the methane fermentation apparatus which uses several pumps conventionally, the number of fixtures (the number of pumps) reduces, and it can aim at reduction of cost. Moreover, since the sand contained in the liquid D in the methane fermentation tank 6 is separated and removed by the sand separator 7 and does not deposit on the bottom of the tank, it deposits on the bottom of the methane fermentation tank as in the conventional methane fermentation apparatus. This eliminates the need to remove the sand, which facilitates maintenance and greatly improves the operating rate. And the gas agitation and liquid agitation of the liquid D in the methane fermentation tank 6 is performed with one pump 9 and the concentration of the anaerobic sludge is maintained at 4 ± 1% as described above, and the heat exchanger 13 Since the liquid temperature is maintained at 36 ± 5 ° C., methane fermentation becomes extremely active, and it is possible to generate digestive gas with a high proportion of methane gas as 70 to 80%.

  The digestion gas generated in the methane fermentation tank 6 is mostly stored in the balloon-shaped gas holder 4 after the most of the water is removed by the demister 15 attached to the vent 6f of the top plate 6d. The digestion gas stored in the gas holder 4 is sent to the gas scrubber 16 shown in FIG. 2 through the pipe L14 and washed with the warm wash water F inside the scrubber. Moisture is removed to some extent by the mist catcher 16a at the upper part of the cleaning device, and the cleaned gas is sent to the gas separator 18 through the pipe line L15. Moreover, the used cleaning water F is stored in the water storage tank 17 and used as cleaning water for the plant facility.

  The gas separator 18 is provided with several pipes inside, by flowing cold water supplied from the water source 19 through the pipe L19 to the pipe, and passing the gas between the pipes, Most of the water contained in the gas is liquefied and removed. The temperature of the cold water flowing in the pipe is raised by heat exchange with the gas, and the heated water is sent to the gas scrubber 16 through the pipe L20 and used as washing water.

  The gas from which most of the moisture has been removed by the gas separator 18 is sent to the gas dryer 20 through the pipe L16, and is filtered by the adsorbent filled in the gas dryer 20, so that almost all of the moisture is removed. It becomes dry gas. The dry gas is sent to the desulfurization column 21 through the pipe L17. After the sulfide such as hydrogen sulfide is removed by the desulfurization column 21, the cross distributor 22 (distributor) is passed through the pipe L18. Sent to. Further, the drain discharged from the gas separator 18, the gas dryer 20, the desulfurization column 21, and the cross distributor 22 is returned to the receiving tank 1 through the pipe L21.

  The gas refined as described above passes from the cross distributor 22 through the pipe line L22 to which the gas meter 23 is attached, a part of which is supplied as fuel to the hot water boiler 24, and the remaining gas is used for fuel and other purposes. The And the hot water heated with the hot water boiler 24 is stored by the hot water storage tank 25, and as mentioned above, in order to maintain each liquid temperature of the squeezing liquid tank 3 and the methane fermentation tank 6 to predetermined temperature, the pipe line L4 Then, the liquid is supplied and circulated to the heat exchangers 12 and 13 of the squeezed liquid tank 3 and the methane fermentation tank 6 through the pipe line L5 and the pipe line L8.

  As can be understood from the above explanation, the methane fermentation treatment plant of the present invention is a simple and low cost type and high treatment efficiency, and is also an excellent treatment plant that is easy to maintain because sand does not deposit on the bottom of the methane fermentation tank. .

It is a schematic explanatory drawing of the principal part of the methane fermentation processing plant which concerns on one Embodiment of this invention. It is a schematic explanatory drawing of the gas refinement | purification part of the same methane fermentation processing plant. It is a schematic sectional drawing of the methane fermentation tank which provided the balloon-shaped gas holder and the simple building on the top plate. It is a schematic plan view of the methane fermentation tank which provided the balloon-shaped gas holder and the simple building on the top plate. It is a perspective view of a sludge adhesion cloth.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Receiving tank 2 Solid-liquid separator 3 Squeezed liquid tank 3a, 6a, Ready-made concrete retaining wall 3b, 6b, 11b Watertight sheet 4 Balloon-shaped gas holder 5 Simple building 5a Aggregate 5b Tent cloth 6 Methane fermentation tank 6c Insulation Material 6d Top plate 6f Vent 7 Sand separator 8 Gas inhaler 9 Pump 10 Electric switching valve 11 Digestive fluid tank 12, 14 Heat exchanger 13 Sludge adhesion cloth 15 Dewaterer (Demister)
16 Gas scrubber 18 Gas separator 20 Gas dryer 21 Desulfurization column 22 Cross distributor A Organic waste B Squeezed liquid D Liquid in methane fermentation tank E Digested liquid

Claims (9)

  The squeezing liquid tank that temporarily stores the squeezed liquid separated from the organic waste, the methane fermentation tank that introduces the squeezed liquid from the squeezed liquid tank and ferments methane, and the gas generated in the methane fermentation tank temporarily The gas holder to store, the sand separator that separates the sand contained in this liquid before returning the liquid extracted from the methane fermentation tank to the methane fermentation tank, and the liquid extracted from the methane fermentation tank to the methane fermentation tank The gas inhaler that inhales the gas supplied from the methane fermentation tank to this liquid, the digestive liquid tank that temporarily stores the digested liquid extracted from the methane fermentation tank, and a pipe that connects them. At least one pump and an electric switching valve are provided. By switching the electric switching valve, the juice is introduced from the juice tank to the methane fermentation tank and removed from the methane fermentation tank. Out Return to the methane fermentation tank, supply of the liquid extracted from the methane fermentation tank to the sand separator, return of the liquid separated from the sand to the methane fermentation tank, to the gas inhaler of the liquid extracted from the methane fermentation tank Methane fermentation treatment plant characterized in that the supply of gas and the return of the gas sucked into the methane fermentation tank and the transfer of the digested liquid extracted from the methane fermentation tank to the digestive liquid tank are performed.   The gas holder is a balloon-type gas holder made of an airtight sheet, and the balloon-type gas holder is installed on the top plate of the methane fermentation tank, and the balloon-type gas holder is inserted through a vent formed in the top plate. The methane fermentation processing plant according to claim 1, wherein the methane fermentation tank is in communication with the methane fermentation tank.   The methane fermentation treatment plant according to claim 2, wherein a water dehydrator is attached to the vent hole.   4. The gas holder according to claim 1, wherein the gas holder is housed in a simple building constructed of aggregate and tent cloth, and an upper end of the gas holder is attached to an upper portion of the simple building. The methane fermentation treatment plant described.   The sludge adhesion cloth which made anaerobic sludge adhere is attached to the inside of the above-mentioned methane fermentation tank, and the concentration of anaerobic sludge with respect to the liquid in a methane fermentation tank is maintained at 4 +/- 1 mass%. Thru | or the methane fermentation processing plant in any one of Claim 4.   The methane fermentation treatment plant according to any one of claims 1 to 5, wherein the bottom of each of the methane fermentation tank, the squeezed liquid tank, and the digestive liquid tank is formed of a water-tight sheet.   The methane fermentation treatment plant according to any one of claims 1 to 6, wherein each side wall of the methane fermentation tank and the squeezed liquid tank is formed of a ready-made concrete retaining wall.   The methane fermentation treatment plant according to any one of claims 1 to 7, wherein a heat insulating material is attached to the outer surface of the side wall of the methane fermentation tank and the squeezed liquid tank.   A heat exchanger is attached to each of the methane fermentation tank and the squeezed liquid tank, and hot water heated by burning the dehumidified and purified gas extracted from the gas holder is supplied to each heat exchanger, and methane fermentation The methane fermentation treatment plant according to any one of claims 1 to 8, wherein the temperature of the tank is kept at 36 ± 5 ° C and the temperature of the squeezed liquid tank is kept at 50 ± 5 ° C.

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