JP3639543B2 - Organic waste treatment method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method and apparatus for efficiently treating organic waste mainly composed of livestock waste and other organic waste such as marine waste and garbage such as kitchen waste by methane fermentation or the like.
[0002]
[Prior art]
Methane gas obtained from methane fermentation treatment of organic waste is an excellent fuel for recovering electricity and heat, and methane fermentation has been tried in the field of sewage treatment, but the properties of the generated gas are not stable. However, electricity cannot be obtained stably, and it takes a lot of money to maintain the generator and it is not used effectively. In addition, attempts have been made to introduce results in the sewage field for methane fermentation of livestock waste such as livestock manure, but it has not been successfully applied due to differences in raw material properties.
[0003]
As a technique for methane fermentation treatment of livestock waste, for example, Japanese Patent Application Laid-Open No. 52-44072 discloses that methane gas is recovered by methane fermentation of livestock waste, and slurry after methane fermentation treatment is dried and fermented to produce compost. A method is disclosed in which part of the recovered methane gas is combusted and the obtained combustion gas is used as a heat source for drying or the like.
[0004]
[Problems to be solved by the invention]
When livestock waste is treated with methane fermentation, the long pepper mixed with feces from livestock farmers cannot be separated efficiently and cannot be treated properly. It has become an environmental pollution problem. Moreover, when drying the long knot separated at the receiving stage and further performing compost fermentation, it is necessary to use an auxiliary fuel as a heat source for drying and fermentation in a severe cold season and the like, which is inefficient.
In addition, when the raw materials mainly composed of livestock waste are heated, anaerobic methane fermentation is carried out following the acid fermentation period of about 12 to 24 hours, but these are fermented in parallel in a single tank. Is difficult. In this case, if a fermenter for acid fermentation is provided separately, a heater and a pump are required for each, and the cost and maintenance burden increase.
[0005]
The present invention has been made in view of the above points, and the object of the present invention is to efficiently extract methane gas from organic waste mainly composed of livestock waste, to produce a liquid fertilizer with a high fertilizing effect, and to produce methane fermentation. In a system that accepts Nagatoro, which is difficult to separate, and separates and composts it, it performs pretreatment that allows Nagatoro to efficiently separate it, and effectively uses waste heat recovered from methane gas in the system, thereby allowing methane fermentation. It is an object of the present invention to provide a method and apparatus for treating organic waste, which can promote compost fermentation without using auxiliary fuel even in severe cold seasons.
[0006]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the organic waste processing method of the present invention recovers methane gas by subjecting organic waste mainly composed of livestock waste to methane fermentation in a methane fermentation tank, and obtaining the methane gas. Is an organic waste processing method for producing liquid fertilizer from slurry (digested liquid) after methane fermentation treatment, and generating feces mixed with straw as a pretreatment of livestock manure And after receiving the urine in one receiving tank, the suspension of sputum and manure is sent to a scraping machine that picks up the sputum and separates it, and the sputum separated by the scraper is solid-liquid separated and dried. Furthermore, it is configured so that it is further fermented into compost, and a part of the liquid-rich manure that is separated from the straw is sent to the methane fermentation process, and the rest of the manure is sent back to the receiving tank upstream of the scraper and circulated. (See FIGS. 1, 2, and 3).
[0007]
In the above method, when organic waste mainly composed of livestock waste is received in the waste receiving tank and then charged into the methane fermentation tank, a heating tube group is arranged in the waste receiving tank, and methane gas Warm water that has been heated using waste heat generated by power generation and / or use of heat through the heating tube group to heat the receiving tank that received the organic waste, and the organic waste that is the raw material in the receiving tank After the acid fermentation (preliminary fermentation, primary fermentation) is completed, anaerobic digestion can be performed in a methane fermentation tank to promote methane fermentation (see FIGS. 1 and 4).
In addition, in the above method, after drying the straw separated from livestock manure with a drying facility, when the compost is made with a fermentation facility, the drying facility uses waste heat generated by power generation and / or heat utilization with methane gas. And the fermenting equipment is heated, and compost can be manufactured without requiring auxiliary fuel (see FIG. 1).
[0008]
In addition, in the above method, when a hot-wire flow meter is provided in the piping for extracting methane gas from the methane fermentation tank, the piping on the upstream side of the flow meter is heated to such an extent that it is not naturally cooled or frozen and condensed in the gas. The flow meter can be stabilized by removing water and heating the dehumidified gas through a pipe immediately before the flow meter (see FIG. 5).
In the above method, when biodesulfurizing the methane gas taken out from the methane fermentation tank by the desulfurization microorganisms in the slurry from the methane fermentation tank, the slurry flowing intermittently from the methane fermentation tank by overflow is divided into two parts, A part of the slurry can be introduced into the desulfurizer without requiring power, and the remaining slurry can be carried out to form liquid fertilizer (see FIG. 6).
[0009]
The organic waste processing apparatus of the present invention includes a receiving pit into which dredged urine and urine are mixed, and a screen in which a suspension of dredging and excreted urine flowing from the receiving pit is lifted and a pin protrudes. A scraper that rolls up the sludge by lifting it up in the inflow direction with a belt, a solid-liquid separator that separates the sputum that has been separated by scraping with the scraper, and manure with a large amount of liquid that has passed through the scraper And a pump for discharging manure separated by the solid-liquid separator, and a pretreatment device for returning a part of the discharged manure to the receiving pit side upstream of the scraper and circulating it A waste receiving tank that accepts organic waste mainly composed of manure discharged from the device, a methane fermenter that inputs organic waste from the waste receiving tank to ferment methane, and a methane fermentation tank Desulfurization to biodesulfurize methane gas And power generation means and / or heat utilization means using methane gas desulfurized by the desulfurization equipment, and slurry (digested liquid) after methane fermentation treatment discharged from the methane fermentation tank can be taken out as liquid fertilizer Digestive fluid storage tank, drying equipment for drying organic waste mainly composed of soot separated by pretreatment equipment, and organic waste mainly composed of soot dried by drying equipment to be composted It is characterized by including the compost fermentation equipment which performs (refer FIG.1, FIG.2, FIG.3).
[0010]
In the above apparatus, a heating tube group in which a number of heating tubes are arranged in tandem via upper and lower main pipings is provided in a waste receiving tank that receives organic waste mainly composed of manure, and power generation means and / or Alternatively, warm water that has been heated using waste heat generated by heat utilization means is allowed to flow through the heating tube group to heat the receiving tank that received the organic waste, and the organic waste that is the raw material in the receiving tank After acid fermentation (preliminary fermentation, primary fermentation), it is preferable to promote anaerobic digestion in a methane fermentation tank to promote methane fermentation (see FIGS. 1 and 4).
In the above-mentioned apparatus, the warm air heated by using the waste heat generated by the power generation means and / or the heat utilization means is supplied to the organic waste drying equipment and / or compost fermentation equipment mainly composed of straw. It is preferable to introduce (see FIG. 1).
[0011]
Moreover, in the above apparatus, a hot-wire flow meter is provided in a pipe for taking out methane gas from the upper end of one end of the methane fermentation tank, a pipe in front of the flow meter is branched downward, and a seal pot is provided in the lower part of the branch pipe. The piping on the upstream side of the flow meter is heated so that it does not cool naturally or freezes so that the condensed water in the gas is removed and collected in the seal pot, and the dehumidified gas is added to the piping immediately before the flow meter. It can be made warm (see FIG. 5).
Moreover, in said apparatus, the pipe | tube for slurry extraction provided in the edge part of a methane fermenter has the substantially reverse U-shaped pipe part which overflows the slurry which flows intermittently, and a substantially reverse U-shaped pipe part. Consists of desulfurization equipment side piping and carry-out branch piping having a smaller diameter than the substantially inverted U-shaped pipe connected below, and desulfurization equipment side piping with a smaller diameter before the desulfurization equipment, intermittently from the methane fermentation tank The flowing slurry is divided into two parts, and a part of the slurry is introduced into the desulfurization apparatus for biodesulfurization without requiring power, and the remaining slurry can be carried out to the digestive fluid storage tank to be used as liquid fertilizer (see FIG. 6). ).
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications. FIG. 1 shows a schematic configuration of an organic waste processing apparatus according to a first embodiment of the present invention. Livestock waste transported from livestock farmers, etc. is solid-liquid separated into a large amount of liquid urine and long manure by the pretreatment device 10, and the liquid waste urine is aquatic wastes crushed by the crusher 12 Along with the daily waste, it is put into the waste receiving tank 14, and the long pepper that is difficult to methane fermentation is sent to the temporary storage facility 16 in the composting process.
[0013]
FIG. 2 shows the configuration of the pretreatment device 10. In the receiving pit 18, urine transported by a tanker or the like and urine mixed with feces transported by a container or the like are placed. The suspension of culm and manure is introduced into the scraper 20 from the receiving pit 18, and the culm is scraped up by the scraper 20 and solid-liquid separated by the solid-liquid separator 22. The excreta that has been sent to the conversion step and has passed through the scraper 20 and has been separated by the solid-liquid separator 22 is carried out by the pump 24. Part of the discharged manure is sent to the methane fermentation process, and the remaining manure is returned to the receiving pit 18 upstream of the scraper 20 for circulation.
[0014]
As shown in FIG. 3, the scraping machine 20 has a screen belt 28 with scraping pins 26 protruding at predetermined intervals, as shown in FIG. 3, and a spindle on which an upper rotor 32 is attached by a motor 30. By rotating, the screen belt 28 moves upward. Reference numeral 34 denotes a lower rotor, and 36 denotes a seal member.
When a suspension of sputum and manure flows from the receiving pit 18 into the scraper 20, the sputum is caught by the scraping pin 26 and swept up, and the excreta having a high liquid content passes between the screen belts 28. To go.
[0015]
The raw material mainly composed of livestock waste put into the waste receiving tank 14 warms the waste receiving tank 14 using hot water heated by surplus heat generated by power generation and / or heat use by methane gas, which will be described later. As a result, acid fermentation (preliminary fermentation, primary fermentation) is performed, and after acid fermentation is completed in the receiving tank 14, it becomes possible to perform anaerobic digestion in the methane fermentation tank 38, thereby promoting methane fermentation. it can. Since this system can efficiently extract methane, the electricity and heat that are obtained are abundant, and even the receiving tank 14 with a little heat dissipation can be sufficiently heated. As a result, acid fermentation can be completed in the receiving tank 14, and it is also possible to receive frozen raw materials in the severe cold season as they are.
[0016]
FIG. 4 shows a heating structure of the waste receiving tank 14, and a large number of heating pipes 40 are arranged in cascade on the wall surface inside the receiving tank 14 as upper and lower main pipes 42 and 44 as hot water trace pipes. . 46 is a hot water inlet and 48 is a hot water outlet. A plurality of such units of the heating tube group 50 are provided on the wall surface in the receiving tank 14. Since the receiving tank 14 can be efficiently heated by this structure, it is possible to perform acid fermentation (preliminary fermentation, primary fermentation) of the raw material in the receiving tank 14.
[0017]
The raw material that has been subjected to acid fermentation in the receiving tank 14 is supplied to the methane fermentation tank 38 for anaerobic methane fermentation. As the methane fermentation tank 38, a horizontal type using a spiral blade stirrer or the like, or a silo type can be used depending on the capacity or the like. is there. In addition, by heating the methane fermentation tank 38 using hot water heated by surplus heat generated by power generation and / or heat generation using the obtained methane gas, anaerobic methane fermentation of the raw material is promoted, and methane can be efficiently used. Can be taken out. Although not shown in FIG. 1, a hot water trace pipe is provided on the wall surface of the methane fermentation tank 38.
[0018]
Methane gas (biogas mainly composed of methane) taken out from the methane fermentation tank 38 is introduced into the desulfurization device 52 in order to remove sulfur components that cause corrosion of the equipment, and desulfurization in the slurry from the methane fermentation tank 38 is performed. Biodesulfurization is performed using microorganisms. The desulfurized methane gas is temporarily stored in the gas holder 54 and then used as fuel for the generator 56 and the hot water heater 58 to generate power and use heat. The hot water heater 58 is supplied with auxiliary fuel such as heavy oil from the fuel tank 60 as necessary. The electric power obtained by the generator 56 is used at each facility in the system, and the surplus power can be used outside the system or sold. The warm water obtained by the warm water heater 58 is warmed by the waste heat of the generator 56, warming the waste receiving tank 14, warming the methane fermentation tank 38, drying equipment 62 and compost fermentation equipment 64 described later. This is used for heating the heat in the fuel tank 60 and for heating the fuel in the fuel tank 60. The used hot water is circulated to the hot water heater 58 via the hot water tank 68.
[0019]
A part of the slurry (digested liquid) after the methane fermentation treatment discharged from the methane fermentation tank 38 is introduced into the desulfurizer 52 and used for biological desulfurization of methane gas, and the remaining slurry is a slurry together with the slurry after desulfurization use. It is sent to the digestive juice storage tank 72 via the receiving tank 70. A part of the slurry from the slurry receiving tank 70 is charged into the waste receiving tank 14. The slurry in the digestive fluid storage tank 72 is carried out as a liquid fertilizer having a high fertilizing effect.
[0020]
After being dried in the sun by the drying facility 62, the long pepper or the like stored in the temporary storage facility 16 is fermented by the compost fermentation facility 64 to become compost. In this case, as described above, warm water from the warm water heater 58 using the recovered methane gas as fuel and warm water heated by the waste heat of the generator 56 are introduced into the heat exchangers 74 and 76 and heated with warm water. The warm air is introduced into the drying facility 62 and the compost fermentation facility 64. As a result, even in the severe cold season when it is difficult to dry in the sun, it is possible to compost Nagatoro etc. without the need for auxiliary fuel. The compost from the compost fermentation facility 64 is stored in the finished compost storage facility 78 and then carried out.
[0021]
FIG. 5 shows a main part of an organic waste processing apparatus according to the second embodiment of the present invention. When a hot-wire flow meter 84 is provided in the generated gas recovery pipe 82 connected to the generated gas outlet 80 of the methane fermentation tank 38, the pipe is branched downward before the flow meter 84 and a seal pot 86 is provided below the branch pipe. the provided, or the pipe 88 up to the front of the flow meter 84 is naturally cooled or frozen warmed to the extent not, harvested seal pot 86 to remove the condensed water in the gas, the flow meter 84 of the previous Heating is performed by a heater 92 or the like in the pipe 90. The gas whose flow rate is measured by the flow meter 84 is sent to the above-described desulfurization apparatus. The hot-wire flow meter is not affected by temperature changes, but becomes unstable when mist is present. By adopting this configuration, the flow meter becomes stable. It is particularly effective in cold regions and severe cold seasons.
Other configurations and operations are the same as those in the first embodiment.
[0022]
FIG. 6 shows an essential part of an organic waste processing apparatus according to the third embodiment of the present invention. The pipe for removing the slurry provided at the end of the methane fermentation tank 38 is connected to a substantially inverted U-shaped pipe portion 94 that overflows the intermittently flowing slurry and a lower portion of the substantially inverted U-shaped pipe portion 94. It consists of a desulfurization apparatus side pipe 96 and a carry-out branch pipe 98 having a diameter smaller than that of the substantially inverted U-shaped pipe portion 94, and a desulfurization apparatus side pipe 100 having a smaller diameter before the desulfurization apparatus. Reference numerals 102 and 104 denote valves. FIG. 6 shows an example of the diameter of the pipe. As described above, desulfurization microorganisms in the slurry are used for biodesulfurization of methane gas, but in order to sufficiently perform the desulfurization treatment, it is preferable that the residence time of the slurry in the desulfurization apparatus is long. Therefore, in the structure as described above, a part of the slurry that flows intermittently from the methane fermentation tank 38 is introduced into the desulfurization apparatus, and the remaining slurry is carried out to the digestion liquid storage tank. By adopting this configuration, power by a pump or the like becomes unnecessary.
Other configurations and operations are the same as those in the first embodiment.
[0023]
【The invention's effect】
Since this invention is comprised as mentioned above, there exist the following effects.
(1) When livestock waste is treated with methane fermentation, feces mixed with feces from livestock farmers can be efficiently separated into feces and fertilizers that are difficult to ferment methane at the receiving stage. Not only will it be promoted, it will also be possible to make composts from Nagatoro.
(2) Since this system can efficiently extract methane, the electricity and heat obtained are abundant, and simple drying equipment and fermentation equipment are installed to assist the Nagatoro separated at the receiving stage even in the severe cold season. Can be composted without fuel.
(3) In this system with abundant heat sources, it is possible to sufficiently heat even a receiving tank with a little heat dissipation, so that the acid fermentation (preliminary fermentation, primary fermentation) of the raw material is received in the receiving tank. It is also possible to accept frozen raw materials in the cold season as they are. Moreover, it can heat efficiently by installing warm water trace piping in a receiving tank.
(4) Not only can methane gas be efficiently extracted from organic waste, but also liquid fertilizer with a high fertilizing effect can be produced.
(5) When a hot-wire flow meter is installed in the gas outlet piping of the methane fermentation tank, the flow meter is stabilized even in cold regions and severe cold seasons by adopting a configuration that can remove mist contained in the generated gas. be able to.
(6) By making the slurry extraction pipe of the methane fermentation tank into the configuration of the present invention, a part of the slurry flowing intermittently can be introduced into the desulfurization apparatus without requiring power, and the biological product of methane gas The residence time required for desulfurization can also be secured.
(7) With this system, equipment costs and operating costs can be reduced, and maintenance is easy.
[Brief description of the drawings]
FIG. 1 is a systematic schematic configuration explanatory view showing an organic waste processing apparatus according to a first embodiment of the present invention.
FIG. 2 is a schematic configuration explanatory view showing a preprocessing apparatus according to the first embodiment of the present invention.
3 is an explanatory plan view showing a scraper in the pretreatment apparatus shown in FIG. 2; FIG.
FIG. 4 is an explanatory diagram of an inner surface configuration showing a heating structure of the waste receiving tank in the first embodiment of the present invention.
FIG. 5 is a schematic configuration explanatory view showing a main part of an organic waste processing apparatus according to a second embodiment of the present invention.
FIG. 6 is a schematic configuration explanatory view showing a main part of an organic waste processing apparatus according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Pretreatment apparatus 12 Crusher 14 Waste receiving tank 16 Temporary storage equipment 18 Reception pit 20 Scraping machine 22 Solid-liquid separator 24 Pump 26 Scraping pin 28 Screen belt 30 Motor 32 Upper rotor 34 Lower rotor 36 Seal member 38 Methane Fermenter 40 Heating pipes 42 and 44 Main pipe 46 Hot water inlet 48 Hot water outlet 50 Heating pipe group 52 Desulfurization device 54 Gas holder 56 Generator 58 Hot water heater 60 Fuel tank 62 Drying equipment 64 Compost fermentation equipment 68 Hot water tank 70 Slurry receiving tank 72 Digestion Liquid storage tanks 74 and 76 Heat exchanger 78 Complete compost storage facility 80 Generated gas outlet 82 Generated gas recovery pipe 84 Flow meter 86 Seal pot 88 and 90 Pipe 92 Heater 94 Substantially U-shaped pipe part 96 and 100 Desulfurization apparatus side pipe 98 Branch piping 102, 104 Valve

Claims (8)

Organic waste, mainly livestock waste, is methane fermented in a methane fermenter to recover methane gas. The resulting methane gas generates power and / or heat, and liquid fertilizer is removed from the slurry after methane fermentation treatment. A method for treating organic waste to be manufactured, and as a pretreatment of livestock manure, after accepting feces and urine mixed with straw in one receiving pit , the suspension of straw and manure is scraped up. The soot separated into the scraping machine and separated by the scraping machine is solid-liquid separated and then dried or fermented into compost. A waste organic waste is returned to the receiving pit side upstream of the scraper and circulated so that the waste is efficiently separated .   When organic waste mainly consisting of livestock waste is received in the waste receiving tank and then put into the methane fermentation tank, a heating tube group is arranged in the waste receiving tank to generate power and / or heat from methane gas. Heated warm water using waste heat generated from the use was passed through the heating tube group to heat the receiving tank that received the organic waste, and finished acid fermentation of the organic waste that was the raw material in the receiving tank. 2. The method for treating organic waste according to claim 1, wherein anaerobic digestion is performed in a methane fermentation tank to promote methane fermentation.   After drying the koji separated from livestock manure in the drying facility, when composting in the fermentation facility, warm the drying facility and the fermentation facility using waste heat generated by power generation and / or heat utilization with methane gas, The method for treating organic waste according to claim 1 or 2, wherein compost is produced without requiring auxiliary fuel. Only set the flow meter hot-wire to the pipe for taking out the methane gas from the methane fermentation tank, the upstream side piping of the flowmeter cooled naturally removed by condensing the moisture in the gas, piping dehumidified gas flowmeter immediately preceding The method for treating organic waste according to claim 1, 2 or 3, wherein the flowmeter is stabilized by heating . The receiving pit into which feces and urine mixed with sputum is thrown in, and the suspension of sputum and feces and urine flowing from the receiving pit is rolled up obliquely upward in the inflow direction by the screen belt with the pin protruding, and the sputum is scraped A scraper that raises, a solid-liquid separator that separates the soot separated by the scraper, and a stool separated by the solid-liquid separator. A pretreatment device that efficiently separates soot by returning and circulating a part of the discharged manure to the receiving pit upstream of the scraper,
A waste receiving tank for receiving organic waste mainly composed of manure discharged from the pretreatment device;
A methane fermentation tank for fermenting methane by introducing organic waste from a waste receiving tank;
A desulfurization device for biodesulfurization of methane gas recovered from the methane fermentation tank;
Power generation means and / or heat utilization means using methane gas desulfurized by a desulfurization apparatus as fuel,
A digestive fluid storage tank that accepts the slurry after the methane fermentation treatment discharged from the methane fermentation tank and can carry it out as liquid fertilizer;
A drying facility for drying organic waste mainly composed of soot separated by the pretreatment device;
An organic waste treatment apparatus comprising: a compost fermentation facility for fermenting and composting organic waste mainly composed of straw dried in a drying facility. In the waste receiving tank that accepts organic waste mainly composed of manure, a heating tube group in which a number of heating tubes are arranged in tandem via upper and lower main piping is provided, and generated by power generation means and / or heat utilization means After warming the heated water using the waste heat that has passed through the heating tube group to heat the receiving tank that has received the organic waste, after the acid fermentation of the organic waste that is the raw material in the receiving tank The organic waste processing apparatus according to claim 5 , wherein anaerobic digestion is performed in a methane fermentation tank to promote methane fermentation. The drying equipment and / or compost fermentation facility organic waste composed mainly of straw, claim 5 which is adapted to introduce a heating with warm air using waste heat generated by the power generation means and / or heat utilization means Or the processing apparatus of the organic waste of 6 . A hot-wire flow meter is installed in the pipe that takes out methane gas from the upper part of one end of the methane fermentation tank, the pipe in front of the flow meter is branched downward, and a seal pot is installed in the lower part of the branch pipe. warmed as condensed water in the gas is collected in excluded seal pot, the piping between the seal pot and a flow meter provided with a heater for heating, dehumidified gas flow meter The organic waste processing apparatus according to claim 5, 6 or 7 , wherein the apparatus is heated by a pipe immediately before .

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