Apparatus and method for treating biogas and anaerobic digestion liquid generated by anaerobic digestion of organic waste

Abstract

The present invention relates to an apparatus and a method for treating biogas and anaerobic digestion liquid generated by anaerobic digestion of organic waste by being connected to an anaerobic digestion device for generating anaerobic digestion liquid containing ammonia nitrogen and biogas containing carbon dioxide by means of anaerobic digestion of organic waste.

Description

Device and method for processing biogas and anaerobic digestate produced by anaerobic digestion of organic waste

[0001] The present invention relates to a device and method for treating biogas and anaerobic digestion liquid produced by anaerobic digestion of organic waste.

[0002] Anaerobic digestion, also known as "methane fermentation," is a biological treatment method for stabilizing organic waste such as food waste, livestock waste, sewage sludge, and manure. Under anaerobic conditions, facultative anaerobes and obligate anaerobes hydrolyze high-molecular-weight organic matter to produce volatile fatty acids such as acetic acid, propionic acid, and butyric acid, and biogas containing methane, hydrogen, carbon dioxide, ammonia, and hydrogen sulfide.

[0003] This anaerobic digestion treatment was not actively used when the activated sludge method became popular, but after the oil crisis in the mid-1970s, it is possible to use recovered biogas (containing 50-70% CH4, 30-50% CO2, and less than 1% ammonia and hydrogen sulfide) as fuel, and compared to the activated sludge method that requires a large amount of air to be ventilated, it has the advantage of low power consumption, the amount of biological sludge generated per unit of organic matter is significantly less than that of the aerobic treatment method, the methane-fermented anaerobic digestate is rich in nitrogen, phosphorus, and humus, and thus has high value as fertilizer, and in addition to the simple decomposition and treatment of waste, it is an eco-friendly resource recycling method that produces fuel and compost, so much research has been actively conducted as an active alternative energy source for petroleum.

[0004] In this regard, Korean Patent No. 10-0936540 discloses an apartment-type anaerobic digestion device for biogas production, which can perform acid production and methane production steps in a single anaerobic digestion tank by moving influent such as livestock manure or food waste in a first-in, first-out manner within a single anaerobic digestion tank so that optimal conditions can be appropriately provided according to the process flow.

[0005] Meanwhile, biogas produced through anaerobic digestion contains a large amount of methane, but also contains carbon dioxide, ammonia, and hydrogen sulfide, among other substances. In order to use it as automobile fuel, a pretreatment process to methanize the biogas is essential, and in particular, a process to remove carbon dioxide, which accounts for 30-40% of the content, is required.

[0006] In addition, in the process of liquefying methane-fermented anaerobic digestion liquid to use it as fertilizer, high-concentration ammonia is evaporated into the atmosphere, which is not only a major source of complaints due to foul odor, but also requires a lot of equipment and operating costs to install odor-reducing facilities to address this issue, so a method is required to recover ammonia before it evaporates into the atmosphere.

[0007] Accordingly, the inventor of the present invention has developed a purification treatment device and method capable of removing carbon dioxide in biogas produced by methane fermentation in an anaerobic digestion device and simultaneously removing ammonia nitrogen in anaerobic digestate produced by methane fermentation, wherein the device and method can produce an ammonium carbonate compound by degassing the ammonia nitrogen and then reacting it with carbon dioxide in the biogas, and has completed the present invention.

[0008] The purpose in one aspect is,

[0009] The present invention provides a device and method for treating biogas and anaerobic digestate produced by anaerobic digestion of organic waste.

[0010] To achieve the above purpose,

[0011] On one hand,

[0012] A device that is connected to an anaerobic digestion device that anaerobically digests organic waste to produce anaerobic digestate containing ammonia nitrogen and biogas containing carbon dioxide, and processes biogas and anaerobic digestate produced by anaerobic digestion of organic waste.

[0013] A carbonated water generation chamber that mixes biogas supplied from the above anaerobic digestion device with water to generate carbonated water;

[0014] A first solid-liquid separator for separating solid and liquid from the anaerobic digestate anaerobically digested in the above anaerobic digestion device;

[0015] A first filtrate stirring chamber connected to the first solid-liquid separator and stirring the first filtrate produced by the solid-liquid separation;

[0016] A CaO injection device that injects CaO into the first filtrate stirring chamber to degas ammonia from the first filtrate;

[0017] An air injection device for injecting air into the first filtrate stirring chamber; and

[0018] A device for processing biogas and anaerobic digestion fluid produced by anaerobic digestion of organic waste is provided, comprising an ammonium carbonate production chamber that receives a mixed solution of biogas and water from the carbonate production chamber and receives ammonia gas and air from the first filtrate stirring chamber to produce ammonium carbonate.

[0019] On another note,

[0020] A method for treating biogas and anaerobic digestate produced by anaerobic digestion of organic waste using a device for treating biogas and anaerobic digestate produced by anaerobic digestion of the above organic waste,

[0021] A carbonated water production step in which biogas containing carbon dioxide produced by anaerobically digesting organic waste is mixed with water to produce carbonated water;

[0022] A first solid-liquid separation step for separating solid and liquid from the anaerobic digestate produced by anaerobically digesting organic waste;

[0023] An ammonia degassing step in which the first filtrate produced by the solid-liquid separation is stirred and CaO and air are added to degas ammonia from the first filtrate; and

[0024] A method for treating biogas and anaerobic digestate produced by anaerobic digestion of organic waste is provided, comprising a step of producing ammonium carbonate by reacting the carbonated water and the degassed ammonia.

[0025] The present invention can recover high-concentration ammonium carbonate usable as nitrogen fertilizer by utilizing anaerobic digestion of organic waste.

[0026] In addition, the present invention can reduce the amount of carbon dioxide emitted during anaerobic digestion treatment by combining carbon dioxide in biogas with ammonia removed from anaerobic digestion fluid to produce ammonium carbonate, and at the same time, can simply solve the problem of odor caused by ammonia nitrogen during anaerobic digestion treatment and the problem of equipment to solve the problem. In addition, the ammonium carbonate produced through the above process can be used to replace urea solution for removing nitrogen oxides (NOx) in incinerators.

[0027] In addition, the present invention can remove carbon dioxide in biogas generated through anaerobic digestion of organic waste, thereby recovering high-purity methane gas from the biogas.

[0028] In addition, the present invention provides a filter cake obtained after solid-liquid separation of anaerobic digestion liquid from which ammonia nitrogen has been removed, which has little or no ammonia content and can be used as a slow-release fertilizer for crop cultivation and soil improvement, and the recovered filtrate has a high Ca ion content, which can reduce carbon dioxide (CO2) and sulfur oxides (SO) in exhaust gas. x ) can be reused as an adsorption solution, which can be sprayed into the incinerator of an incinerator to remove sulfur oxides (SOx ), chlorine (Cl), etc. In addition, the filtrate can be purified to produce purified water.

[0029] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

[0030] FIG. 1 is a schematic diagram of a process diagram of a treatment device for biogas and anaerobic digestion liquid produced by anaerobic digestion of organic waste according to one embodiment;

[0031] FIG. 2 is a schematic diagram of a process diagram of a treatment device for biogas and anaerobic digestion liquid produced by anaerobic digestion of organic waste according to another embodiment;

[0032] Figure 3 is a flow chart of the entire livestock wastewater or food waste treatment process of a first-in, first-out anaerobic digestion device according to one embodiment;

[0033] FIG. 4 is a perspective view showing a heating system of a first-in, first-out anaerobic digestion device according to one embodiment;

[0034] Figure 5 is a perspective view showing the flow of the activation liquid and the fermentation completion liquid of a first-in, first-out anaerobic digestion device according to one embodiment;

[0035] FIG. 6 is a perspective view showing a filtrate stirring chamber and a process for concentrating ammonium carbonate water in a first-in, first-out anaerobic digestion device according to one embodiment;

[0036] Figure 7 is a side view showing a side heating device (side ondol) and a gas stirring process;

[0037] Fig. 8 is a side view showing the observation section shown in Fig. 7 from another side;

[0038] FIG. 9 is a schematic diagram showing a purified gas stirring device and a purified gas circulation device according to one embodiment;

[0039] Figure 10(a) is a schematic diagram showing a structure in which a first upper gas layer suction pipe and a purification device are connected to a purification gas stirring device, which receives biogas from a gas layer at the top of an anaerobic digestion tank, purifies it, and then supplies it to a lower acid gas supply pipe and an acid pipe;

[0040] Figure 10(b) is a schematic diagram showing a purified gas circulation device having a structure in which a second upper gas layer suction pipe and a purification device are connected, and biogas is supplied from the gas layer above the anaerobic digestion tank, purified, and then supplied to the upper gas layer;

[0041] Figure 11(a) is a schematic diagram showing a second purification device;

[0042] Figure 11(b) is a schematic diagram showing the first purification device.

[0043] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. First, when assigning reference numerals to components in each drawing, it should be noted that, where possible, identical components are assigned the same reference numerals even if they are shown in different drawings. Furthermore, in describing the present invention, if a detailed description of a related known structure or function is deemed obvious to those skilled in the art or may obscure the gist of the present invention, the detailed description may be omitted.

[0044] On one hand,

[0045] A device that is connected to an anaerobic digestion device that anaerobically digests organic waste to produce anaerobic digestate containing ammonia nitrogen and biogas containing carbon dioxide, and processes biogas and anaerobic digestate produced by anaerobic digestion of organic waste.

[0046] A carbonated water generation chamber (200) that passes biogas supplied from the above anaerobic digestion device (100) through water to dissolve carbon dioxide and generate carbonated water;

[0047] A first solid-liquid separator (300) that separates solid and liquid from the anaerobic digested liquid in the above anaerobic digestion device;

[0048] A first filtrate stirring chamber (400) connected to the first solid-liquid separator and stirring the first filtrate produced by the solid-liquid separation;

[0049] A CaO injection device (410) that injects CaO into the first filtrate stirring chamber to degas ammonia from the first filtrate;

[0050] An air injection device (420) for injecting air into the first filtrate stirring chamber;

[0051] A device for processing biogas and anaerobic digestion fluid produced by anaerobic digestion of organic waste is provided, comprising an ammonium carbonate production chamber (500) that receives a mixed solution of biogas and water from the carbonate production chamber (200) and receives ammonia gas and air from the first filtrate stirring chamber (400) to produce ammonium carbonate.

[0052] Hereinafter, a device (1000) for processing biogas and anaerobic digestion liquid generated by anaerobic digestion of organic waste according to one embodiment will be described in detail for each component with reference to the drawings.

[0053] FIG. 1 is a flow chart of a process for treating biogas and anaerobic digestate generated by anaerobic digestion of organic waste, which is performed by a device for treating biogas and anaerobic digestate generated by anaerobic digestion of organic waste according to an embodiment, and FIG. 2 is a flow chart of a process for treating biogas and anaerobic digestate generated by anaerobic digestion of organic waste, which is performed by a device for treating biogas and anaerobic digestate generated by anaerobic digestion of organic waste according to another embodiment.

[0054] Referring to FIGS. 1 and 2, a biogas and anaerobic digestate treatment device (1000) according to one embodiment is connected to an anaerobic digestion device (100) that anaerobically digests organic waste to produce anaerobic digestate containing ammonia nitrogen and biogas containing carbon dioxide.

[0055] The above anaerobic digestion device (100) is a device that anaerobically digests organic waste.

[0056] A raw material input section for inputting organic waste; and

[0057] It may include an anaerobic digestion tank that anaerobically digests organic waste to produce anaerobic digestate containing ammonia nitrogen and biogas containing carbon dioxide.

[0058] At this time, the organic waste fed into the anaerobic digestion device may be, but is not limited to, concentrated sludge, excrement, food waste, food waste water (food waste waste water), etc., and may include other organic waste that undergoes anaerobic digestion.

[0059] In addition, the anaerobic digestion device (100) is preferably a first-in, first-out anaerobic digestion device that performs acid production and methane production in a single anaerobic digestion tank, and performs anaerobic digestion by moving the influent to the anaerobic digestion tank divided into multiple areas in a first-in, first-out manner.

[0060] The FIFO anaerobic digestion system has the advantage of high organic matter decomposition rate, does not release even a portion of the raw materials fed in on the same day, and can easily recycle the final byproducts by gradually breaking down the layer separation phenomenon in the digestion tank.

[0061] The above FIFO anaerobic digestion device is described in more detail below.

[0062] Meanwhile, referring to FIGS. 1 and 2, a biogas and anaerobic digestion liquid treatment device (1000) according to one embodiment includes a carbonated water generation chamber (200) that is connected to the anaerobic digestion device (100) and mixes biogas supplied from the anaerobic digestion device with water to dissolve carbon dioxide and generate carbonated water.

[0063] The above carbonated water generation chamber (200) is a chamber that dissolves carbon dioxide in the biogas generated from the anaerobic digestion device into water, thereby increasing the methane content in the biogas and at the same time, carbonated water generated by dissolving carbon dioxide in water can be used to adsorb ammonia gas degassed from the anaerobic digestion liquid.

[0064] A device (1000) for treating biogas and anaerobic digestion fluid according to one embodiment can further remove not only carbon dioxide but also ammonia and hydrogen sulfide contained in biogas through the carbonated water generation chamber and the ammonium carbonate generation chamber (500), thereby obtaining methane of higher purity.

[0065] Accordingly, the biogas and anaerobic digestion liquid treatment device (1000) according to one embodiment may further include a methane gas recovery unit that is connected to the carbonated water generation chamber or the ammonium carbonate generation chamber and separates and recovers methane gas; and may further include a methane gas recovery unit that is connected to the desulfurization device and separates and recovers methane gas.

[0066] In addition, referring to FIG. 2, the biogas and anaerobic digestion liquid treatment device (1000) according to one embodiment may further include a biogas stirring device (110) that receives biogas from the anaerobic digestion device (100) and supplies it to a carbonated water production chamber (200), and receives biogas from which carbon dioxide has been removed from the carbonated water production chamber (200) and supplies it to the anaerobic digestion device (100).

[0067] The above biogas stirring device (110) is a device that circulates biogas between the anaerobic digestion device (100) and the carbonated water generation chamber (200), and through the biogas stirring device (110), biogas containing a large amount of carbon dioxide can be supplied from the anaerobic digestion device (100) to the carbonated water generation chamber (200), and biogas from which carbon dioxide has been removed can be supplied from the carbonated water generation chamber (200) to the anaerobic digestion device (100).

[0068] Referring to FIGS. 1 and 2, a biogas and anaerobic digestion liquid treatment device (1000) according to one embodiment includes a first solid-liquid separator (300) connected to the anaerobic digestion device (100) to separate the anaerobic digestion liquid into solid and liquid.

[0069] The above first solid-liquid separator (300) is a unit that is connected to the anaerobic digestion tank of the anaerobic digestion device (100) and separates solid and liquid from the anaerobic digested liquid.

[0070] Organic waste is separated into upper, middle, and lower layers according to specific gravity. The upper layer contains fat, vinyl, rice straw, etc., the middle layer contains a liquid solution having a similar specific gravity to water, and the lower layer contains substances with a high specific gravity. When the organic waste is anaerobicly digested, organic substances are decomposed by gas stirring, periodic propeller stirring, and upper layer digestion liquid spraying, but the anaerobic digested liquid still contains residues that have not been decomposed.

[0071] Accordingly, the first solid-liquid separator (300) obtains the first filtrate through solid-liquid separation, and at this time, the solid residue is separated into an upper layer and a lower layer. The upper layer residue, such as vinyl and lignin of rice straw, is separated through upper layer discharge water filtration, and the difficult-to-decompose lower layer residue, such as fibrous lignin, is separated through lower layer discharge water filtration.

[0072] The solid residue separated by filtration at this time can be used as mature compost.

[0073] Referring to FIGS. 1 and 2, a biogas and anaerobic digestion liquid treatment device (1000) according to one embodiment includes a first filtrate stirring chamber (400) connected to the first solid-liquid separator (300) and stirring the first filtrate produced by the solid-liquid separation;

[0074] A CaO injection device (410) that injects CaO into the first filtrate stirring chamber to degas ammonia from the first filtrate; and

[0075] It includes an air injection device (420) for injecting air into the first filtrate stirring chamber.

[0076] The above first filtrate stirring chamber (400), CaO injection device (410), and air injection device (420) are devices for removing ammonia from the first filtrate separated from the first solid-liquid separator (300).

[0077] When the first filtrate is supplied to the first filtrate stirring chamber (400), CaO is added from the CaO injection device (410) to stir the first filtrate, and air is added from the air injection device (420) to effectively release the degassed ammonia without dissolving it in the first filtrate.

[0078] At this time, the first filtrate can be heated to further promote ammonia degassing, and preferably, by adding 2%-3% of CaO to the solid-liquid separated anaerobic digestion liquid at about 35°C and heating it to 60°C or higher, ammonia degassing can be further promoted.

[0079] Referring to FIGS. 1 and 2, a biogas and anaerobic digestion liquid treatment device (1000) according to one embodiment includes an ammonium carbonate production chamber (500) that receives carbonated water from the carbonated water production chamber (200) and receives ammonia gas and air from the first filtrate stirring chamber (400) to produce ammonium carbonate.

[0080] Meanwhile, the biogas and anaerobic digestion liquid treatment device (1000) according to one embodiment may further include a pump for transporting ammonia and air degassed from the first filtrate stirring chamber (400) to the ammonium carbonate production chamber (500), and the pump may preferably be a water-sealed vacuum pump.

[0081] Ammonium carbonate can be produced by sucking ammonia degassed from the first filtrate stirring chamber (400) through the above pump and then transferring it to the ammonium carbonate production chamber (500) so that ammonia is adsorbed into carbonated water.

[0082] A device (1000) for treating biogas and anaerobic digestate according to one embodiment mixes biogas generated from the anaerobic digestion device (100) with water to obtain carbonated water with dissolved carbon dioxide, and then removes ammonia from the anaerobically treated digestate and allows it to be continuously adsorbed into the carbonated water, thereby producing high-concentration ammonium carbonate.

[0083] Meanwhile, referring to FIG. 2, the biogas and anaerobic digestion liquid treatment device (1000) according to one embodiment may further include a device configuration for filtering and separating the first filtrate with reduced ammonia concentration.

[0084] More specifically, the biogas and anaerobic digestion liquid treatment device (1000) according to one embodiment may further include an iron salt injection device (430) for injecting iron salt into the first filtrate in the first filtrate stirring chamber, as a device for increasing the filtration efficiency of the first filtrate with reduced ammonia concentration.

[0085] At this time, the iron salt may preferably be Fe2(SO4)3, and the amount to be added may be determined by collecting a small amount of the first filtrate, adding the Fe2(SO4)3 solution, and measuring the filtration efficiency.

[0086] A device (1000) for treating biogas and anaerobic digestion fluid according to one embodiment can shorten the process time by increasing the filtration efficiency through the injection of iron salt.

[0087] In addition, the biogas and anaerobic digestion liquid treatment device (1000) according to one embodiment includes a second solid-liquid separator (600) connected to the first filtrate stirring chamber (400) to separate the first filtrate from which ammonia has been removed;

[0088] A filter cake recovery unit (810) that separates and recovers the filter cake generated by separation in the second high-liquid separator; and

[0089] It may further include a second filtrate recovery unit (820) for separating and recovering the second filtrate obtained by separating the first filtrate containing iron salt from the solid.

[0090] At this time, a filter press may be used as the second solid-liquid separator (600), but is not limited thereto, and other known devices for solid-liquid separation of anaerobic digestion liquid may be used.

[0091] Additionally, the first filtrate may be a first filtrate in which an iron salt is added to form a chelate bond.

[0092] The filter cake, which is a solid residue obtained from the second solid-liquid separator, is a chelated substance that is insoluble in water and contains a large amount of minerals and unknown growth factors in addition to the essential fertilizer components for plants lacking only the N component, and can be used as a fertilizer and soil conditioner.

[0093] The above filter cake can be absorbed by plants because it dissolves in water-insoluble substances, acid rain, or root acids secreted from plant roots. In addition, it is less leached by rainfall and groundwater, but has excellent water retention capacity, so it can greatly contribute to crop growth when used as a slow-release fertilizer in soils with poor drainage such as reclaimed land, slopes in Gangwon-do with severe leaching, or soil in Jeju-do.

[0094] In addition, the second filtrate obtained by separating and recovering the second filtrate by separating the first filtrate containing iron salts contains a large amount of low molecular weight substances combined with Ca ions, which are carbon dioxide (CO2) and sulfur oxides (SO x ) to form a precipitate, so when the exhaust gas is treated with the second filtrate, carbon dioxide (CO2) and sulfur oxides (SO) in the exhaust gas x ) can be removed, and also when applied to incinerators, sulfur oxides (SO x ), chlorine (Cl) components can be removed.

[0095] Meanwhile, the biogas and anaerobic digestion liquid treatment device (1000) according to one embodiment may further include a purified water generation device (700) that purifies the second filtrate recovered from the second filtrate recovery unit to generate purified water;

[0096] The above purification water generation device (700)

[0097] A Ca ion removal unit (710) that removes Ca ions from the second filtrate recovered from the second filtrate recovery unit;

[0098] An activated sludge treatment unit (720) that treats the second filtrate from which the Ca ions have been removed with activated sludge; and

[0099] It may include a reduced pressure distillation unit (730) for distilling the activated sludge-treated discharged water under reduced pressure.

[0100] At this time, the Ca ion removal unit (710) can remove the second filtrate by supplying it to the generator exhaust gas scrubber water and causing calcium ions to precipitate.

[0101] The above-mentioned activated sludge treatment unit (720) is a device that treats the second filtrate from which Ca ions have been removed with activated sludge, and may be a device that treats the supernatant from which calcium ions have been precipitated in the second filtrate with activated sludge.

[0102] In addition, the reduced pressure distillation unit (730) that distills the activated sludge-treated discharged water under reduced pressure can recover purified water that can be used as waste water and process water or discharge it into the water system by distilling the activated sludge-treated discharged water under reduced pressure.

[0103] The above activated sludge treated discharge water can be treated using waste heat from the generator, but because the temperature of the waste heat that can be obtained from the generator is not high, using a pressure reducing evaporator to increase heat transfer efficiency has excellent advantages in terms of heat energy transfer efficiency and additional energy cost reduction.

[0104] In addition, by using multi-stage reduced pressure evaporation that allows a solution with a high concentration to undergo heat exchange in an initial evaporation chamber and reuses the latent heat of vaporization of the water vapor generated in the initial evaporation chamber as the heat of evaporation of the solution in a low concentration chamber, an energy reuse efficiency of about 40% can be obtained compared to single-stage reduced pressure evaporation.

[0105] Meanwhile, the biogas and anaerobic digestion liquid treatment device (1000) according to one embodiment can be connected to a first-in, first-out anaerobic digestion device as an anaerobic digestion device.

[0106] The anaerobic digestion process is basically divided into two stages: acid production and methanogenesis. Since the microorganisms operating in each stage have very different physiological characteristics and nutritional requirements, changes in external conditions can upset the balance between the two biota, thereby reducing the efficiency of the overall process. As an alternative, a two-stage fermentation process (two-phase method) has been proposed, which divides the reactor into two reactors: one for acid production and one for methanogenesis. In the traditional one-stage reaction process (one-phase method), acid production and methanogenesis occur simultaneously in a single reactor, making it impossible to optimally control the acid production and methanogenesis stages. In addition, there was a problem that stability was broken due to sensitivity to changes in the wastewater flowing in from the outside.

[0107] In contrast, the two-phase method has the advantages of easily maintaining suitable environmental conditions at each stage, appropriately controlling the loading rate of the methane reactor, and preventing rapid pH decline due to the accumulation of low-grade fatty acids, thereby preventing inhibition of methane fermentation in advance. However, this two-phase method has disadvantages in terms of cost, such as the need for separate reactors and a system for transferring the reactor from the first to the second reactor, and the cumbersome problem of separately controlling the reaction conditions of each reactor.

[0108] On the other hand, the FIFO anaerobic digestion device can perform the acid production step and the methane production step in one anaerobic digestion tank, and while researching to improve the difficulty in simultaneously satisfying the optimal conditions for acid production and methane production, which was pointed out as a problem of the conventional one-phase method, the optimal conditions can be appropriately provided according to the process flow while moving the influent such as livestock manure or food waste in a FIFO manner in one anaerobic digestion tank, so that it is structurally simple and can maximize the production efficiency of biogas by providing the optimal anaerobic digestion conditions.

[0109] Hereinafter, a first-in, first-out type anaerobic digestion device according to one embodiment and a device for processing biogas and anaerobic digestate generated by anaerobic digestion of organic waste connected to the device are described with reference to FIGS. 3 to 11.

[0110] Referring to Figure 3, the first-in, first-out type narrow-body fire extinguishing device is more specifically,

[0111] A sedimentation tank into which organic waste is fed;

[0112] A flow control tank that receives the influent water passing through the above-mentioned sedimentation tank and supplies it to the anaerobic digestion tank at a preset value;

[0113] An anaerobic digestion tank including zones 1, 2, 3, and 4, designed so that the influent passing through the above flow adjustment tank undergoes methane fermentation in the order of first-in, first-out to produce biogas and at the same time moves to the next anaerobic digestion zone;

[0114] A gas supply pipe and a gas distribution tube for imparting fluidity to the inflow water of the above zones 1, 2, 3 and 4;

[0115] A lower suction pipe for sucking the anaerobic digestion liquid from the lower layer of the above anaerobic digestion tank zone 4;

[0116] A middle layer suction pipe for sucking the anaerobic digestion liquid of the above anaerobic digestion tank section 4;

[0117] It may include an upper suction pipe for sucking anaerobic digestion liquid from the upper layer of the above anaerobic digestion tank zone 4; and a device for capturing biogas produced in the upper gas layer of the above anaerobic digestion tank zones 1 to 4.

[0118] In addition, the anaerobic digestion liquid sucked from the above-mentioned middle layer suction pipe may further include a device for mixing the anaerobic digestion liquid with organic waste fed into the sedimentation tank as an activating liquid to promote sediment separation and perform fungal inoculation.

[0119] The above FIFO anaerobic digestion device does not require a separate gas storage facility, does not require complex pretreatment when inputting the influent, and can provide optimal conditions for the growth of methanogens by controlling the temperature of the influent through the entire anaerobic digestion process using waste heat. In addition, by enabling anaerobic digestion of the fermented liquid in a FIFO manner, it can eliminate factors that may reduce the efficiency of removing odorous components in the post-treatment process when the unfermented liquid input is selected. In addition, by purifying and recycling the biogas produced in-house without installing a complex and expensive stirring facility, it can induce floating and homogenization of sediments contained in the influent and gradually move the influent in order to achieve the optimal methane fermentation effect.

[0120] Referring to Fig. 4, the anaerobic digestion device of the first-in, first-out type is equipped with an ondol pipe (9) on the bottom of the anaerobic digestion tank zones 1 (5), 2 (6), 3 (7), and 4 (8) to maintain an optimal methane fermentation temperature.

[0121] The above-mentioned ondol pipe (9) provides the optimal temperature of 35-55℃ for methane production by methanogenic bacteria within the anaerobic digestion tank. Since the temperature of the initially introduced influent is approximately 18℃ in the summer and approximately 8℃ in the winter, the above-mentioned ondol pipe (9) can minimize the temperature deviation between the optimal fermentation temperature for methane production and the temperature of the initially introduced influent.

[0122] In addition, the FIFO-type anaerobic digestion device may further include a side heating device (side ondol) installed on the side of the sedimentation tank (1), the flow control tank (2) and the anaerobic digestion tank section 1 (5), thereby minimizing the temperature difference between the optimal fermentation temperature for methane production and the initially introduced influent.

[0123] The anaerobic digestion tank of each zone (5, 6, 7, 8) of the anaerobic digestion device of the above-mentioned first-in, first-out type is characterized by having a structure in which a space is secured between the upper part of the influent water flowing into each zone and the ceiling of each zone in which biogas produced as a result of methane fermentation is stored (see Fig. 4).

[0124] When biogas is produced as a result of methane fermentation, the produced gas is stored between the ceiling of each zone and the upper part of the influent, and as a result, the first-in, first-out anaerobic digestion device does not require a separate biogas storage device.

[0125] Each zone (5, 6, 7, 8) of the above-mentioned FIFO-type anaerobic digestion tank has a structure in which it is divided into sections by dividing walls (5', 6', 7'). In this case, except for the upper space where biogas is stored, the ends of each dividing wall (5', 6', 7') are open in an 'L' shape from the inner wall of the anaerobic digestion tank. The influent and biogas move to the next section through the open space.

[0126] The dividing walls (5', 6', 7') of the above anaerobic digestion tank have a structure in which the dividing walls (5') of zones 1 and 2, and the dividing walls (7') of zones 3 and 4 are opened at the same position, and the dividing walls (6') of zones 2 and 3 are opened at the opposite end to the opening positions of the dividing walls (5') of zones 1 and 2, and the dividing walls (7') of zones 3 and 4. As a result, the influent moves in a zigzag pattern throughout the entire anaerobic digestion tank like an animal's digestive organ.

[0127] Referring to Fig. 9, each zone (5, 6, 7, 8) of the FIFO-type anaerobic digestion tank has a structure in which an acid gas supply pipe (27) and an air diffuser (26) for imparting fluidity to the influent are installed along the perimeter of the walls on the bottoms of the walls except for the walls in the direction in which the sedimentation tank (1) and the flow control tank (2) are installed, the dividing walls (5') of zones 1 and 2, and the dividing walls (7') of zones 3 and 4. More specifically, the acid gas supply pipe (27) and the air diffuser (26) are provided along the perimeter of the side wall of the dividing wall installed between zones 2 and 3 in the zone 2 direction, the bottom of the inner wall from zone 1 to zone 2 perpendicular to the dividing wall, and the bottom of the inner wall of zone 1 perpendicular to the inner wall from zone 1 to zone 2. The acid gas supply pipes and air diffusers of zones 1 and 2 are provided along the perimeter of these walls. In addition, the side wall bottom of the zone 3 direction of the separation wall installed between zones 2 and 3, the inner wall bottom from zones 3 to 4 perpendicular to the separation wall, and the inner wall bottom of zone 4 perpendicular to the inner wall from zones 3 to 4 are provided with gas supply pipes and ventilation pipes for zones 3 and 4 along the perimeter of these walls.

[0128] The above-mentioned first-in, first-out anaerobic digestion tank does not incorporate a conventional fully mixed propeller agitator. Instead, the gas supplied through the acid gas supply pipe (27) and the aeration tube (26) functions as an agitator to provide fluidity to the influent.

[0129] Referring to Fig. 8, in particular, in zone 1 (5) of the anaerobic digestion tank, an acid gas partition wall (25) is installed in front of a side heating device (side ondol) (24) described below to vertically guide the flow of acid gas introduced from an acid pipe (26) installed at the bottom of the wall, and then the acid gas passing through the acid gas partition wall (25) imparts clockwise fluidity to the inflow water passing through zone 1 (5), thereby providing stirring and fluidity. Meanwhile, the introduced acid gas may be a gas that has undergone a treatment process that is differentiated according to the zone of the anaerobic digestion tank. This will be described in more detail in the relevant section below.

[0130] Furthermore, the acid gas partition wall (25) installed in the FIFO-type anaerobic digestion tank is not limited to zone 1 of the anaerobic digestion tank, but is installed in front of the wall where the acid gas supply pipe (27) and the acid pipe (26) are installed on the floor from zone 1 to zone 4 within the anaerobic digestion tank, thereby further imparting fluidity to the inflow water passing through each zone.

[0131] Referring to Fig. 7, the FIFO-type anaerobic digestion tank is provided with a side heating device (side ondol) (24) capable of exchanging heat supplied from an external heat source on the opposite side wall surface of the dividing wall (5') of zone 1 (5) for the purpose of minimizing the deviation between the temperature of the initial influent and the optimal methane fermentation temperature, thereby maximizing the methane fermentation efficiency in zones 2, 3, and 4 of the anaerobic digestion tank. At this time, the heat supplied from the external heat source can increase energy efficiency by using the waste heat of the heat exchanger used as the final cooling water of the multi-stage depressurization evaporator.

[0132] Meanwhile, referring to FIG. 9, the gas layer of zone 2 (6) of the FIFO-type anaerobic digestion tank is provided with a first upper gas layer suction pipe (34) that recovers biogas from the upper gas layer of zone 2 (6) and supplies it to the acid gas supply pipe (27) and the acid pipe (26) provided in zones 1 to 4 (5, 6, 7, 8). Through this, the biogas supplied to the acid gas supply pipe (27) and the acid pipe (26) can be used to stir the anaerobic digestion liquid and provide fluidity.

[0133] Meanwhile, it is preferable that the gas used to stir the anaerobic digestion liquid and provide fluidity be supplied after removing carbon dioxide, ammonia, and hydrogen sulfide contained in the biogas so as not to disturb the methane fermentation conditions, and furthermore, it is preferable that the carbon dioxide, ammonia, and hydrogen sulfide be removed in order to increase the purity of the biogas ultimately produced.

[0134] For this purpose, the first upper gas layer suction pipe (34) can be connected to a biogas purification device (210), and at this time, the structure in which the first upper gas layer suction pipe (34) and the purification device (210) are connected can be referred to as a purified gas stirring device (Figs. 9 and 10(a)).

[0135] After recovering the biogas of the upper gas layer of the zone 2 (6) through the above-mentioned purified gas stirring device, carbon dioxide, ammonia and hydrogen sulfide are removed, and purified gas from which carbon dioxide, ammonia and hydrogen sulfide have been removed can be supplied to the acid gas supply pipe (27) and the acid pipe (26) provided in zones 1 to 4 (5, 6, 7, 8).

[0136] In addition, the anaerobic digestion tank zone 4 (8) is equipped with a second upper gas layer suction pipe (35) that recovers the upper gas layer biogas of the zone 4 (8) and supplies it to the upper part of zone 1 (5).

[0137] In addition, at this time, the second upper gas layer suction pipe (35) may be connected to a purification device (210) to supply purified gas to the upper part of the zone 1 (5), and at this time, the structure in which the second upper gas layer suction pipe (35) and the purification device (210) are connected may be referred to as a purified gas circulation device (Figs. 9 and 10 (b)).

[0138] As shown in FIG. 9, FIG. 10(a) and FIG. 10(b), the purified gas stirring device and the purified gas circulating device may have the same configuration except for the connected pipes, or the configuration of the purification device (210) may be different.

[0139] For example, the purified gas stirring device and the purified gas circulating device may include both the first purifying device (28) and the second purifying device (28') which will be described later as the purifying device (210), but the purified gas stirring device may not include the second purifying device (28'), while the purified gas circulating device may be designed to include the second purifying device (28').

[0140] After recovering biogas from the upper gas layer of the zone 2 (6) through the above-mentioned purified gas circulation device, carbon dioxide, ammonia and hydrogen sulfide can be removed, and purified gas from which carbon dioxide, ammonia and hydrogen sulfide have been removed can be supplied to the upper gas layer of the zone 1 (5).

[0141] Hereinafter, the structure of the purification device (210) and the purified gas stirring device and purified gas circulation device including the same will be described in more detail with reference to FIGS. 9 to 11.

[0142] FIG. 9 and FIG. 10(a) are schematic diagrams schematically showing a state in which a purified gas stirring device having a structure in which a first upper gas layer suction pipe (34) and a purification device (210) are connected receives biogas from a gas layer in the upper part of an anaerobic digestion tank, purifies it, and supplies it to an acid gas supply pipe (27) and an acid pipe (26) in the lower part, and FIG. 10(b) is a schematic diagram schematically showing a state in which a purified gas circulation device having a structure in which a second upper gas layer suction pipe (35) and a purification device (210) are connected receives biogas from a gas layer in the upper part of an anaerobic digestion tank, purifies it, and supplies it to an upper gas layer.

[0143] Figures 11(a) and 11(b) are schematic diagrams showing the purification device (210) in more detail.

[0144] Referring to FIGS. 10 and 11, the purification device (210) includes a first purification device (28) and a second purification device (28') connected to the first purification device (28).

[0145] The above first purification device (28) includes a biological desulfurization device that removes carbon dioxide, ammonia, and hydrogen sulfide in biogas, and removes ammonia and hydrogen sulfide using a red sulfur bacteria culture solution.

[0146] Referring to Fig. 11(b), the first purification device (28)

[0147] A closed tank (hereinafter referred to as 'Type A tank') that receives biogas transferred from the gas layer of the anaerobic digestion tank, mixes it with water, and dissolves carbon dioxide, hydrogen sulfide, and ammonia in the biogas; and

[0148] An open tank (hereinafter referred to as 'Type B tank') connected to the Type A tank, which receives a solution containing the carbon dioxide, hydrogen sulfide and ammonia dissolved therein, mixes it with a red sulfur bacterial culture medium, and allows outside air to flow in to remove ammonia and hydrogen sulfide in the biogas;

[0149] The solution treated in the above B-type tank is supplied again to the A-type tank, and the structure is such that biogas with carbon dioxide, ammonia, and hydrogen sulfide removed is supplied to the anaerobic digestion tank.

[0150] Accordingly, the FIFO anaerobic digestion device according to one embodiment can remove carbon dioxide, ammonia, and hydrogen sulfide through the biological desulfurization device (28), and thus has the advantage of being able to produce high-quality biogas more easily than other anaerobic digestion tanks during the operation process.

[0151] At this time, the A-type chamber of the first purification device (28) may be connected to the carbonated water generation chamber (200) described above or may be itself.

[0152] Additionally, the B-type chamber of the first purification device (28) may be connected to the aforementioned ammonium carbonate production chamber (200) or may be itself.

[0153] More specifically, the above first purification device (28)

[0154] An aeration pipe (65) through which biogas transferred from the gas layer of the anaerobic digestion tank is supplied;

[0155] A closed tank (hereinafter referred to as 'Type A tank') that mixes biogas supplied from the above-mentioned acidification device (65) with water and dissolves carbon dioxide, hydrogen sulfide, and ammonia in the biogas into water;

[0156] A drain pipe (66) through which the solution in the above-mentioned 'Type A tank' is discharged from the bottom of the Type A tank by the biogas supply pressure;

[0157] An open tank containing a red sulfur bacterial culture medium (hereinafter referred to as “Type B tank”);

[0158] A level sensor (61) that detects the solution level of the above B tank;

[0159] Aeration pipe (63) supplying outside air to the above B tank;

[0160] An inlet pipe (69) connected to the drain pipe (66) of the above-mentioned A-type tank and allowing the solution discharged from the lower part of the above-mentioned A-type tank to flow into the upper part of the above-mentioned B-type tank;

[0161] A ball top (62) for controlling the water level, which is connected to and supported by the above-mentioned intake pipe (69);

[0162] A lower drain pipe (70) for draining the solution treated in the above B-type tank;

[0163] A drainage pump (64) connected to the above drainage pipe (70) and turned on / off according to the water level detection information of the level sensor;

[0164] An inlet pipe (67) that injects the solution of the above Type B tank from the bottom of the Type B tank to the top of the Type A tank; and

[0165] It may include an exhaust pipe (68) that returns the gas discharged from the upper part of the above-mentioned A-type tank to the anaerobic digestion tank.

[0166] The gas returned through the exhaust pipe (68) is a purified gas from which carbon dioxide, ammonia and hydrogen sulfide have been removed, and thus the first purification device (28) can return the purified gas, from which carbon dioxide, ammonia and hydrogen sulfide in the biogas have been significantly reduced, to the anaerobic digestion tank through the above structure.

[0167] At this time, carbon dioxide is dissolved in tank A, but in the solution transferred to tank B, carbonic acid may be vaporized out of the open tank due to the pressure difference. In addition, tank A of the first purification device (28) supplies ammonia and hydrogen sulfide dissolved in water to tank B, thereby reacting with oxygen supplied from the outside air inside tank B, and removing ammonia and hydrogen sulfide in the form of ammonium sulfate (NH4)2SO4, as shown in the following reaction formula 1.

[0168] [Reaction Formula 1]

[0169] 2NH3+ H2S + 2O2→ (NH4)2SO4

[0170] The A-type tank of the above first purification device (28) is a closed tank, and it is preferable to maintain an appropriate internal pressure and water level so that the gas flowing in from the gas layer of the anaerobic digestion tank can supply dissolved water to the B-type tank, and it is more preferable that the internal pressure is maintained at 0.4-0.6 kg / ㎠.

[0171] It is preferable that the B-type tank of the above first purification device (28) contain a red sulfur bacterial culture solution. Some enzymes in the red sulfur bacterial culture solution convert carbon dioxide and hydrogen sulfide in the biogas into the form of formaldehyde (CH2O) and sulfuric acid (H2SO4) salts according to the following reaction formula 2, thereby removing hydrogen sulfide from the biogas containing 50-70% CH4, 30-50% CO2, and less than 1% ammonia and hydrogen sulfide, and simultaneously removing some of the large amount of carbon dioxide. In addition, it is believed that the converted sulfuric acid additionally reacts with ammonia and is converted into the form of ammonium sulfate, as shown in the following reaction formula 3. Furthermore, the red sulfur bacterial culture solution circulates not only through the B-type tank, but also through the A-type tank and the B-type tank to achieve the same purpose.

[0172] [Reaction Formula 2]

[0173] 2CO2+H2S +2H2O → 2(CH2O) + H2SO4

[0174] [Reaction Formula 3]

[0175] H2SO4+ 2NH3→ (NH4)2SO4

[0176] As a result of the above reaction, hydrogen sulfide contained in the biogas can be additionally removed. In particular, the conventional gas-stirred anaerobic digestion tank in which the anaerobic digestion liquid is stirred without removing ammonia and hydrogen sulfide has been pointed out as a factor that adversely affects the biogas production environment (methanogenic bacteria growth) due to the accumulation of ammonia and hydrogen sulfide inside the anaerobic digestion tank. However, by applying the first purification device (28), the gas from which carbon dioxide, hydrogen sulfide, and ammonia have been removed, i.e., the purified upper biogas, can be used for stirring the anaerobic digestion liquid, and as a result, the carbon dioxide and hydrogen that have passed through the A-type tank can be supplied as substrates for methane production to the methanogenic bacteria inside the anaerobic digestion liquid.

[0177] In addition, when the concentration of hydrogen sulfide fed into the first purification device (28) is high, it can be removed by converting it into the form of pure sulfur (S) at a high speed. That is, when the concentration of hydrogen sulfide is high, the rate at which hydrogen sulfide (H2S) is oxidized to sulfur (S) by red sulfur bacteria is higher than the rate at which sulfur (S) is converted to sulfate anion (SO4 2- ) progresses relatively quickly compared to the rate of oxidation, so a large amount of pure sulfur particles accumulate in the purification device solution, floating on the vessel walls or in the solution. This sulfur can be separated using a simple filter.

[0178] Furthermore, it is preferable that the B-type tank of the first purification device (28) be supplied with ammonia and external air degassed from the first filtrate stirring chamber (400). This allows the carbon dioxide in the biogas to be further dissolved in the aqueous solution, thereby further increasing the removal efficiency.

[0179] In addition, the level sensor (61) present in the B-type tank of the first purification device (28) is equipped with three sensor rods (a, b, c) of different lengths. When the water level of the B-type tank is detected by the sensor rod (a) of the shortest length, the drain pump (64) is operated to supply water containing dissolved carbon dioxide, ammonia, and hydrogen sulfide to the A-type tank, and when the water level of the B-type tank is detected by the sensor rod (b) of the middle length, the operation of the drain pump (64) is stopped, and the removal reaction of ammonia and hydrogen sulfide is continuously performed while the solution circulates in the A-type tank and the B-type tank without supplying gaseous oxygen to the A-type tank.

[0180] The above first purification device (28) separates the biogas supplied through the first upper gas layer suction pipe (34) and the second upper gas layer suction pipe (35) of the anaerobic digestion tank by solubility in the A-type tank and supplies the undissolved biogas to the acid gas supply pipe (27) and the acid pipe (26) at the bottom of the anaerobic digestion tank through the exhaust pipe (68) at the top of the A-type tank. To explain this in more detail, among the biogas transferred to the A-type tank, ammonia (NH4), hydrogen sulfide (H2S), and carbon dioxide (CO2), which are easily soluble in water, are dissolved in water, and the other components are discharged through the exhaust pipe at the top of the A-type tank and supplied to the acid gas supply pipe (27) and the acid pipe (26) at the bottom of the anaerobic digestion tank, and the water in the A-type tank is supplied to the B-type tank while the reaction 2CO2 + H2S + 2H2O → 2(CH2O) + H2SO4, represented by the above reaction formula 2, is performed. In the above B-type tank, as described above, the rate at which H2S is oxidized to S by red bacteria is from S to SO4 2- As a result, the phenomenon of temporarily accumulating a large amount of S is applied, and S is converted to SO4 by the dissolved oxygen supplied to the B tank. 2- is converted to SO4 2- is dissolved NH 4+By combining with ammonia, it reacts rapidly to form ammonium sulfate (see reaction formula 3). That is, this reaction occurs continuously while circulating through tanks A and B.

[0181] The B-type tank of the first purification device (28) can produce ammonium carbonate corresponding to the amount of ammonia provided from the first filtrate stirring chamber (400). That is, carbon dioxide and ammonia can be captured and stored in the form of ammonium carbonate. The concentrated recovery of ammonium carbonate can be performed by recovering circulating water at a level of 80% of the saturated solubility, supplying additional water, mixing in a red sulfur bacteria culture solution, and restarting. The recovered solution can be used as a raw material for nitrogen fertilizer by settling or filtering, and furthermore, it can be used as a substitute for urea water for removing nitrogen oxides (NOx) in an incinerator, and can also be used as a substitute for urea fertilizer in agricultural use. For example, it can be added to an incinerator SNCR to remove nitrogen oxides (NOx).

[0182] Meanwhile, the purification device (210) includes a second purification device (28') connected to the first purification device (28) to increase the hydrogen sulfide removal efficiency.

[0183] Referring to Fig. 11(a), a preferred embodiment of the second purification device (28') includes an inlet pipe (71) through which biogas from which hydrogen sulfide has been partially removed flows in through the first purification device (28);

[0184] It may include an aeration pipe (72) for oxidizing biogas supplied from the above inlet pipe (71); a closed tank (hereinafter, “Type A’ tank”) containing water containing iron (II) hydroxide or iron (III) hydroxide that reacts with hydrogen sulfide of the biogas supplied from the above aeration pipe (72); and an exhaust pipe (73) for discharging biogas from which hydrogen sulfide has been removed.

[0185] Specifically, the second purification device (28') dissolves biogas, from which more than 99% of ammonia and some hydrogen sulfide have been removed, supplied through a supply pipe (71) connected to the exhaust pipe (68) at the top of the A-type tank of the first purification device (28), through an acid pipe (72), and reacts the remaining hydrogen sulfide with iron (II) hydroxide or iron (III) hydroxide included in the second purification device (28') to remove the remaining hydrogen sulfide in the form of iron sulfide and water. The second purification device (28') can be used by being connected in series to the A-type tank of the first purification device (28).

[0186] At this time, it is more preferable to use iron (±) hydroxide or iron (III) hydroxide manufactured by the method for manufacturing mineral hydroxide described in 'Method for manufacturing organic chelate' (Korean Patent No. 0481326 and U.S. Patent No. 7087775) applied for and registered by the inventors of the present invention.

[0187] The above iron(II) hydroxide or iron(III) hydroxide is a substance obtained in the form of Fe(OH)2 or Fe(OH)3 by reacting conventional divalent or trivalent iron such as FeSO4, FeCl2, or FeCl3 with NaOH in an aqueous solution. The above Fe(OH)2 or Fe(OH)3 can be obtained by centrifuging the product obtained to remove NaCl as shown in the following reaction formula 4.

[0188] [Reaction Formula 4]

[0189] FeCl2+ 2NaOH → Fe(OH)2+ 2NaCl

[0190] FeCl3+ 3NaOH → Fe(OH)3+ 3NaCl

[0191] Since the above iron (II) hydroxide or iron (III) hydroxide reacts 100% with hydrogen sulfide, which is a gaseous component dissolved into the removal solution system within the device by the aeration tube in the reaction tank of the second purification device (28'), the removal efficiency depends on the gas dissolving capacity of the aeration tube. Compared to the conventional desulfurization device that removes hydrogen sulfide by aeration under high pressure and adsorbing and reacting iron (III) hydroxide FeO(OH) and iron (III) oxide Fe2O3 with gaseous hydrogen sulfide, the aeration speed (gas treatment capacity) is far superior, and in terms of reaction efficiency, it is superior to the conventional desulfurization device that depends on the purity of iron (III) hydroxide and the surface area of ​​the pellets.

[0192] Specifically, in terms of removal efficiency, the conventional desulfurization device ("Final Report on Demonstration of Biogas Production and Energy Utilization Technology through Application of Abnormal Anaerobic Process to Livestock Wastewater", p. 151, September 2006, Ministry of Commerce, Industry and Energy) adsorbs 130 g of hydrogen sulfide per kg of Fe2O31, but the second purification device (28') can adsorb about 478 g of hydrogen sulfide per kg of Fe(OH)31, showing a removal efficiency that is about 3.7 times better. In addition, in terms of gas treatment, it shows a ventilation speed of about 4 N㎥ / min, which is far superior to 2.5 N㎥ / hr of the conventional desulfurization device, so it can be said to be superior in terms of treatment capacity. Also, molecules such as FeS, Fe2S3 combined with hydrogen sulfide circulate in a suspended state between tanks A and B, and are oxidized again by oxygen supplied from tank B to detach molecular sulfur, and then recombine with H2S in tank A, repeating the process and circulating between tanks A and B. Therefore, the cost of consumables can be innovatively reduced, and when the concentration of sulfur becomes excessive, the yellow color becomes stronger, and the gas removal rate is measured to determine the exchange of the solution. The solid content in the solution can be used as a fertilizer to reinforce sulfur components.

[0193] As described above, the first purification device (28) can partially reduce the carbon dioxide content in biogas by consuming carbon dioxide when removing hydrogen sulfide using enzymes produced from the red sulfur bacteria culture solution contained therein.

[0194] Specifically, while biogas produced in a conventional anaerobic digestion tank for biogas production contains CH450-70% and CO230-50%, if the first purification device (28) and / or the second purification device (28') are used, the second purification device (28') can be independently applied for the purpose of removing hydrogen sulfide from the biogas produced from the anaerobic digestion tank, and further, if the first purification device (28) and the second purification device (28') are used in combination, high-purity biogas can be supplied to the anaerobic digestion tank and used as a stirring gas for the anaerobic digestate, thereby maintaining optimal anaerobic digestion conditions (prevention of accumulation of ammonia and hydrogen sulfide in the digestate).

[0195] A device (1000) for processing biogas and anaerobic digestate generated by anaerobic digestion of organic waste according to one embodiment includes a purification device (210) connected to the FIFO-type anaerobic digestion device, and can generate purified biogas having a significantly increased methane content by removing carbon dioxide, ammonia, and hydrogen sulfide contained in the biogas generated by the anaerobic digestion device, and can also generate ammonium carbonate by combining carbon dioxide supplied through the purification device (210) and ammonia supplied through the first filtrate stirring chamber (400). The above process has a synergistic effect on carbon dioxide capture, thereby further increasing biogas purity, i.e., methane concentration.

[0196] Meanwhile, referring to FIG. 3, the section 4 (8) of the anaerobic digestion tank is provided with upper, middle, and lower suction pipes, and in one embodiment, the first solid-liquid separator (300) of the device (1000) for treating biogas and anaerobic digestion liquid generated by anaerobic digestion of organic waste receives the final fermentation liquid (sludge liquid) through the upper and lower suction pipes and separates it into solid and liquid, and the activated liquid sucked from the middle suction pipe is used as a starter inoculation liquid when the influent is livestock wastewater, and can be used for dilution depending on the concentration when the influent is food waste.

[0197] The above anaerobic digestion device does not require a separate gas storage facility, as the gas layer at the top of the anaerobic digestion tank also serves as a gas storage facility. Furthermore, the operation of additional devices, such as a connected power generation engine, can be controlled by the gas pressure in the gas layer. Due to this, combustion through the surplus gas combustor does not occur at all, such as by controlling the generator load and turning it on and off. The surplus gas combustor only operates in the event of an emergency shutdown due to a generator problem.

[0198] In addition, the anaerobic digestion device can improve the digestion rate and obtain mature compost by operating on the principle of first-in, first-out of the influent. In addition, the anaerobic digestion device does not require special stirring facilities inside the anaerobic digestion tank, and since it uses the biogas it produces after purification, it can significantly complement the shortcomings of the existing biogas stirring method, and it can achieve the optimal methane fermentation effect by resolving the floating phenomenon and homogenization of sediment contained in the influent without adversely affecting the fermentation process, and can gradually move the influent.

[0199] In addition, the anaerobic digestion device can produce high-purity biogas by sucking biogas from the gas layer of the anaerobic digestion tank and recirculating the gas from which carbon dioxide, ammonia, and hydrogen sulfide have been removed through the purification device (210). Through the purification device (210), the continuous concentration of ammonia and hydrogen sulfide, which has been pointed out as a disadvantage of the conventional gas-stirred anaerobic digestion tank and which inhibits the growth of methanogens, can be prevented.

[0200] In addition, the first purification device (28) is a composite of a type A tank and a type B tank, and can remove 99% or more of ammonia and 30% or more of hydrogen sulfide contained in biogas, and the second purification device (28') including iron (II) hydroxide or iron (III) hydroxide used in connection with the first purification device (28) can remove 99% or more of hydrogen sulfide generated by increasing the number of device passes.

[0201] In addition, the first purification device (28) can primarily reduce the carbon dioxide content in the biogas by consuming carbon dioxide when the enzyme produced from the red sulfur bacteria culture solution contained therein removes hydrogen sulfide. Furthermore, by supplying the remaining carbon dioxide and hydrogen in the biogas as substrates for the methanogenic bacteria present in the digester, the carbon dioxide, which is an impurity, can be converted into methane, thereby secondarily reducing the carbon dioxide content. Accordingly, by using the first purification device (28) in the anaerobic digestion tank, the carbon dioxide content can be reduced to 20% or less, thereby producing biogas with a methane content of 80% or more (see Table 1).

[0202] Table 1

[0203]

[0204] The above Table 1 shows the results of measuring the ammonia, hydrogen sulfide, and carbon dioxide removal efficiency of the first purification device (28) according to the present invention. Specifically, the components and contents of the biogas before being fed into the first purification device (28) were measured at the gas pipe between the blower (29) and the A-type tank of Fig. 11 (b) using a GASTEC Detector tube (manufacturer: Japan) while passing through the device (28) once, twice, and three times (measurement position 1), and the components and contents of the biogas passing through the device (28) were measured at the position exiting the A'-type tank of the device (28') of Fig. 11 (a) (measurement position 2). Referring to Table 1, ammonia was 100% removed in just the first pass, hydrogen sulfide was removed by about 68% in the first pass, about 80% in the second pass, and about 94% in the third pass, and carbon dioxide was contained in the biogas at 20% or less, indicating that a higher purity biogas can be produced from an anaerobic digestion tank including a purification device according to the invention.

[0205] Hereinafter, the operating status of the anaerobic digestion device of the above structure will be described with reference to Fig. 3.

[0206] Influent such as livestock wastewater, food waste, etc. is fed into the settling tank (1) and heated by receiving heat from the floor underfloor heating system and side underfloor heating system installed inside the flow adjustment tank (2) and the side of Zone 1. The heated influent is fed and discharged simultaneously, so it sequentially passes through Zones 2, 3, and 4 of the anaerobic digestion tank in a first-in, first-out manner, and biogas as a result of anaerobic digestion is generated and stored in the upper part of each zone. A side heating device (side underfloor heating system) (24) that utilizes external waste heat is installed on the side wall of Zone 1 of the anaerobic digestion tank settling tank flow adjustment tank, thereby minimizing the difference between the temperature of the influent and the optimal anaerobic digestion temperature. In addition, the underfloor heating pipe installed on the floor of Zones 1 to 4 supplies heat to the influent to achieve the same purpose.

[0207] In the bottoms of zones 1, 2, 3, and 4 of the anaerobic digestion tank, acid gas supply pipes and diffusers are installed to agitate and provide fluidity to the influent water passing through each zone. The gas is supplied to the acid gas supply pipes and diffusers of zones 1 to 4 by sucking the upper biogas of zones 2 and 4 of the anaerobic digestion tank through a water-sealed vacuum pump, and removing carbon dioxide, ammonia, and hydrogen sulfide contained in the biogas. The biogas stored in the anaerobic digestion device is delivered to a biogas and anaerobic digestate treatment device according to one embodiment and used as a carbon dioxide providing source for producing ammonium carbonate, and the biogas from which carbon dioxide is additionally removed by producing ammonium carbonate has a high methane concentration and can be used as fuel for power generation / heat production. In addition, when applied to ultra-pure methane storage (methane for fuel cells and green hydrogen fuel), it can innovatively reduce the cost of high-purity purification (extending the filter replacement cycle and maintenance costs, etc.).

[0208] The sludge (final fermentation liquid) discharged through the upper suction pipe and the lower suction pipe among the final fermentation liquid (sludge liquid) that has reached the anaerobic digestion tank zone 4 and completed anaerobic digestion is supplied to the first filtrate stirring chamber (400) through the first solid-liquid separator (300), and the solid residue can be used as mature compost. Meanwhile, in the middle layer of the anaerobic digestion tank zone 4, there exists an activated liquid with a specific gravity similar to that of water, and these can be supplied to the sedimentation tank through the middle layer suction pipe. In addition, the solid residue separated from solid and liquid through the first filtrate separator (300) is used as mature compost, the first filtrate is used as an ammonia providing source for producing ammonium carbonate, and the filtrate from which ammonia has been degassed is again subjected to solid-liquid separation by adding iron salt, and the solid residue is used as a slow-release fertilizer, and the second filtrate is used as a fertilizer to remove carbon dioxide (CO2) and sulfur oxides (SO) in exhaust gas. x ) can be used as an adsorption solution and can be sprayed into an incinerator to remove sulfur oxides (SOx ) and chlorine (Cl) adsorption. It can also be reused as wastewater and process water through purification treatment.

[0209]

[0210] On another note,

[0211] A method for treating biogas and anaerobic digestate produced by anaerobic digestion of organic waste using a device for treating biogas and anaerobic digestate produced by anaerobic digestion of the above organic waste,

[0212] A carbonated water production step in which biogas containing carbon dioxide generated by anaerobically digesting organic waste is allowed to pass through water to produce carbonated water;

[0213] A first solid-liquid separation step for separating solid and liquid from the anaerobic digestate produced by anaerobically digesting organic waste;

[0214] An ammonia degassing step in which the first filtrate produced by the solid-liquid separation is stirred and CaO and air are added to degas ammonia from the first filtrate; and

[0215] A method for treating biogas and anaerobic digestate produced by anaerobic digestion of organic waste is provided, comprising a step of producing ammonium carbonate by reacting the carbonated water and the degassed ammonia.

[0216] Hereinafter, a method for processing biogas and anaerobic digestate generated by anaerobic digestion of organic waste according to one embodiment will be described in detail with reference to the drawings.

[0217] A method for treating biogas and anaerobic digestate according to one embodiment is a method for treating biogas and anaerobic digestate using a device connected to an anaerobic digestion device that anaerobically digests organic waste to produce anaerobic digestate containing ammonia nitrogen and biogas containing carbon dioxide, and treating biogas and anaerobic digestate produced by anaerobic digestion of organic waste.

[0218] The above anaerobic digestion device generates biogas in the process of anaerobically digesting organic waste. The biogas generated at this time contains 50-70% methane as its main component, but also contains 30-50% carbon dioxide. Therefore, in order to use the biogas as fuel, a process for removing carbon dioxide is required.

[0219] In addition, the anaerobic digestion device generates anaerobically digested digestate during the process of anaerobically digesting organic waste. The anaerobic digestate generated at this time contains a large amount of ammonia nitrogen, and the ammonia contained therein is 100% green hydrogen ammonia. The amount of nitrogen currently produced in Korea is so large that, if compost liquid fertilizer is included, it can be sprayed more than twice the national cultivated area, but it is being neglected as a source of water pollution. A method is required to recover ammonia, a source of green hydrogen, by converting livestock waste and organic waste into biogas.

[0220] According to one embodiment, a method for treating biogas and anaerobic digestate comprises removing carbon dioxide from the biogas by dissolving carbon dioxide contained in the biogas in water, degassing ammonia from the anaerobic digestate, and then providing the carbon dioxide dissolved in water (carbonated water) to bind it in the form of ammonium carbonate, thereby removing carbon dioxide from the biogas and simultaneously removing ammonia from the anaerobic digestate.

[0221] In addition, a method for treating biogas and anaerobic digestate according to one embodiment is performed by first separating the anaerobic digestate from solids and liquids, removing ammonia through the ammonia stripping process on the first filtrate, and then separating the solids and liquids in a second manner, thereby recovering a solid residue (filter cake) with reduced ammonia and using it as an insoluble, slow-release fertilizer, and the filtered second filtrate contains a large amount of Ca ions, thereby reducing carbon dioxide (CO2) and sulfur oxides (SO) in the exhaust gas. x) can be used as an adsorption solution, which can be sprayed into an incinerator to remove sulfur oxides (SO x ), and can also be used to remove chlorine (Cl).

[0222] In addition, the method for treating biogas and anaerobic digestion fluid according to one embodiment can purify the second filtrate, or obtain purified water that can be used as wastewater and process water through purification treatment.

[0223] Specifically, the second filtrate contains a large amount of low molecular weight substances bound to Ca ions, but this is carbon dioxide (CO2) and sulfur oxides (SO x ) can be added to separate (remove) precipitation from the second filtrate, and the second filtrate from which the Ca ions have been removed is treated with activated sludge, and the discharged water treated with the activated sludge is subjected to reduced pressure distillation, thereby separating salts and recovering purified water that can be used as waste water and process water.

[0224] Accordingly, the method for treating biogas and anaerobic digestate according to one embodiment can reduce the amount of carbon dioxide emitted during anaerobic digestion, and at the same time, solve the problem of odor caused by ammonia nitrogen during anaerobic digestion and the problem of equipment for solving the problem, and at the same time, recover high-concentration ammonium carbonate that can be used as nitrogen fertilizer by utilizing anaerobic digestion of organic waste with carbon dioxide produced during biogas fermentation, and further, recover high-purity methane gas by removing carbon dioxide from biogas, and further, separate the anaerobic digestate from which ammonia nitrogen has been removed to solid-liquid, and filter cake and exhaust gas carbon dioxide (CO2) and sulfur oxides (SO2) that can be used as a slow-acting fertilizer for crop cultivation and soil improvement. x ) can be used as an adsorption solution or as recycled water and process water.

Claims

1. A device that is connected to an anaerobic digestion device that anaerobically digests organic waste to produce anaerobic digestate containing ammonia nitrogen and biogas containing carbon dioxide, and processes biogas and anaerobic digestate produced by anaerobic digestion of organic waste. A carbonated water generation chamber that mixes biogas supplied from the above anaerobic digestion device with water to generate carbonated water; A first solid-liquid separator for separating solid and liquid from the anaerobic digestate anaerobically digested in the above anaerobic digestion device; A first filtrate stirring chamber connected to the first solid-liquid separator and stirring the first filtrate produced by the solid-liquid separation; A CaO injection device that injects CaO into the first filtrate stirring chamber to degas ammonia from the first filtrate; An air injection device for injecting air into the first filtrate stirring chamber; and A device for treating biogas and anaerobic digestion fluid produced by anaerobic digestion of organic waste, comprising an ammonium carbonate production chamber that receives a mixed solution of biogas and water from the carbonate production chamber and receives ammonia gas and air from the first filtrate stirring chamber to produce ammonium carbonate.

2. In paragraph 1, A device for treating biogas and anaerobic digestion fluid produced by anaerobic digestion of organic waste, further comprising an iron salt injection device for injecting iron salt into the first filtrate in the first filtrate stirring chamber.

3. In paragraph 1, A device for treating biogas and anaerobic digestion fluid produced by anaerobic digestion of organic waste, further comprising a second solid-liquid separator connected to the first filtrate stirring chamber and separating the first filtrate from which ammonia has been removed.

4. In paragraph 3, A filter cake recovery unit that separates and recovers the filter cake generated by separation in the second high-liquid separator; and A device for treating biogas and anaerobic digestion fluid produced by anaerobic digestion of organic waste, further comprising a second filtrate recovery unit for separating and recovering a second filtrate obtained by separating a solid from a first filtrate into which iron salts have been added.

5. In paragraph 4, A device for treating biogas and anaerobic digestion fluid produced by anaerobic digestion of organic waste, further comprising a purified water generating device that purifies the second filtrate recovered from the second filtrate recovery unit to produce purified water.

6. In paragraph 5, The above purification water generation device A Ca ion removal unit that removes Ca ions from the second filtrate recovered in the second filtrate recovery unit; An activated sludge treatment unit that treats the second filtrate from which the Ca ions have been removed with activated sludge; and A device for treating biogas and anaerobic digestion fluid produced by anaerobic digestion of organic waste, comprising a reduced pressure distillation unit for distilling the activated sludge-treated discharged water under reduced pressure.

7. In paragraph 1, A device for treating biogas and anaerobic digestate produced by anaerobic digestion of organic waste, further comprising a biogas stirring device that receives biogas from the anaerobic digestion device and supplies it to a carbonated water production chamber, and receives biogas from which carbon dioxide has been removed from the carbonated water production chamber and supplies it to the anaerobic digestion device.

8. In paragraph 1, A device for processing biogas and anaerobic digestion fluid generated by anaerobic digestion of organic waste, further comprising an ammonium carbonate recovery unit connected to the above ammonium carbonate generation chamber and separating and recovering ammonium carbonate.

9. In paragraph 1, A device for processing biogas and anaerobic digestion fluid generated through anaerobic digestion of organic waste, further comprising a methane gas recovery unit connected to the carbonated water generation chamber or the ammonium carbonate generation chamber and separating and recovering methane gas.

10. In paragraph 1, The above anaerobic digestion device A device for processing biogas and anaerobic digestate generated through anaerobic digestion of organic waste, which is a first-in, first-out anaerobic digestion device that performs anaerobic digestion by moving influent to anaerobic digestion tanks divided into multiple areas in a first-in, first-out manner while performing acid production and methane production in a single anaerobic digestion tank.

11. In paragraph 10, The above FIFO anaerobic digestion device is, A sedimentation tank into which organic waste is fed; A flow control tank that receives the influent water passing through the above-mentioned sedimentation tank and supplies it to the anaerobic digestion tank at a preset value; An anaerobic digestion tank including zones 1, 2, 3, and 4, designed so that the influent passing through the above flow adjustment tank undergoes methane fermentation in the order of first-in, first-out to produce biogas and at the same time moves to the next anaerobic digestion zone; A gas supply pipe and a gas distribution tube for imparting fluidity to the inflow water of the above zones 1, 2, 3 and 4; A lower suction pipe for sucking the anaerobic digestion liquid from the lower layer of the above anaerobic digestion tank zone 4; A middle layer suction pipe for sucking the anaerobic digestion liquid of the above anaerobic digestion tank section 4; A device for treating biogas and anaerobic digestate produced by anaerobic digestion of organic waste, comprising: an upper suction pipe for sucking anaerobic digestate in the upper layer of the anaerobic digestion tank zone 4; and a device connected to the gas layers of the anaerobic digestion tank zones 1 to 4 for capturing the produced biogas.

12. In paragraph 11, The above first solid-liquid separator is a device for processing biogas and anaerobic digestion fluid produced by anaerobic digestion of organic waste, which receives anaerobic digestion fluid sucked by the lower suction pipe and the upper suction pipe.

13. In paragraph 11, It further includes a purification device that removes carbon dioxide, ammonia and ammonia contained in the biogas, The above purification device A closed tank ('Type A tank') that receives biogas transferred from the gas layer of the anaerobic digestion tank and mixes it with water to dissolve carbon dioxide, hydrogen sulfide, and ammonia in the biogas; and An open tank ('Type B tank') connected to the above Type A tank, which receives a solution containing the carbon dioxide, hydrogen sulfide and ammonia and mixes it with a red sulfur bacteria culture solution, and allows outside air to flow in to remove ammonia and hydrogen sulfide in the biogas; A device for treating biogas and anaerobic digestate produced by anaerobic digestion of organic waste, comprising a first purification device having a structure in which the solution treated in the above-mentioned B-type tank is supplied again to the A-type tank, and the biogas from which carbon dioxide, ammonia, and hydrogen sulfide have been removed is supplied to the anaerobic digestion tank.

14. In paragraph 13, The above purification device An inlet pipe through which biogas with some hydrogen sulfide removed flows through the first purification device; An aeration device that aerates biogas flowing in from the above inlet pipe; A closed tank (hereinafter, “Type A’ tank”) containing water containing iron (II) hydroxide or iron (III) hydroxide that reacts with hydrogen sulfide of biogas supplied from the above-mentioned acid source; and A device for treating biogas and anaerobic digestate produced by anaerobic digestion of organic waste, further comprising a second purification device including an exhaust pipe (73) for discharging biogas from which hydrogen sulfide has been removed.

15. In paragraph 13, The above anaerobic digestion device further includes a first upper gas layer suction pipe that recovers biogas from the upper gas layer of the anaerobic digestion tank zone 2 and supplies it to the acid gas supply pipe and the acid gas pipe provided in zones 1 to 4. The above purification device is a device for processing biogas and anaerobic digestion liquid generated by anaerobic digestion of organic waste, which is connected to the first upper gas layer suction pipe and supplies purified biogas to the acid gas supply pipe and acid pipe.

16. In paragraph 13, The above anaerobic digestion device further includes a second upper gas layer suction pipe that recovers biogas from the upper gas layer of the anaerobic digestion tank zone 4 and supplies it to the upper gas layer of zone 1. The above purification device is a device for processing biogas and anaerobic digestion liquid produced by anaerobic digestion of organic waste, which is connected to the second upper gas layer suction pipe and supplies purified biogas to the upper gas layer of the zone 1.

17. A method for treating biogas and anaerobic digestate generated from anaerobic digestion of organic waste using a device for treating biogas and anaerobic digestate generated from anaerobic digestion of organic waste in accordance with paragraph 1, A carbonated water production step in which biogas containing carbon dioxide produced by anaerobically digesting organic waste is mixed with water to produce carbonated water; A first solid-liquid separation step for separating solid and liquid from the anaerobic digestate produced by anaerobically digesting organic waste; An ammonia degassing step in which the first filtrate produced by the solid-liquid separation is stirred and CaO and air are added to degas ammonia from the first filtrate; and A method for treating biogas and anaerobic digestate produced by anaerobic digestion of organic waste, comprising a step of producing ammonium carbonate by reacting the carbonated water and the degassed ammonia.

18. In paragraph 17, The ammonium carbonate produced above is nitrogen oxide (NO) in the incinerator. x ) A method for treating biogas and anaerobic digestate produced by anaerobic digestion of organic waste, which are used as a substitute for element water for removal.

19. In paragraph 17, The first filtrate, which has been degassed of ammonia by adding CaO and air, is used as a sulfur oxide (SO) in the incinerator. x ) and chlorine (Cl), which are used to remove biogas and anaerobic digestate produced by anaerobic digestion of organic waste.

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