KR102336002B1 - Anaerobic digestion system for treating of organic waste - Google Patents

Abstract

The present invention relates to an anaerobic digestion system for organic waste treatment, which treats organic waste using anaerobic microorganisms in an intermediate storage tank and an anaerobic digestion tank to produce sludge and methane gas. The present invention comprises: an intermediate storage tank for storing the inflow water of organic waste to be digested and performing a pre-treatment process; an anaerobic digestion tank for receiving the water to be treated stored in the intermediate storage tank and decomposing the organic waste to generate biogas and digested sludge; a transfer pipe for transferring the water to be treated stored in the intermediate storage tank to the anaerobic digestion tank; a gas storage tank for collecting and storing the biogas generated in the anaerobic digestion tank; a sludge discharge pipe for discharging the digested sludge generated in the anaerobic digestion tank; and a sludge storage tank for storing the digested sludge discharged from the sludge discharge pipe. According to the present invention, the microorganisms in a reaction tank are evenly dispersed and arranged by stirring the same so as not to generate a dead flow zone in the reaction tank.

Description

Anaerobic digestion system for treating of organic waste }

The present invention relates to an anaerobic digestion facility for processing organic waste, and more specifically, anaerobic digestion for organic waste treatment to generate sludge and methane gas by treating organic waste using anaerobic microorganisms in an intermediate storage tank and anaerobic digestion tank It is an invention about equipment.

As the amount of organic waste such as food waste, livestock waste, and organic fraction continues to increase, the treatment technology for it is becoming more important.

As such, a method for treating organic waste can be divided into an anaerobic digestion method and an aerobic digestion method, wherein the anaerobic digestion method consumes less energy than an aerobic digestion method, It is a trend that is preferred over aerobic digestion because energy recovery can be expected according to the production of biogas).

On the other hand, the digestion facility for anaerobic digestion is a device that generates biogas by anaerobically digesting an organic mixture by anaerobic microorganisms.

In particular, since 2012, as environmental regulations on livestock excreta such as the ban on marine excretion of livestock manure according to the London Convention become more severe, interest in biogas recovery and energy conversion using livestock manure is rapidly increasing.

In the case of Korea, converting biogas into energy is emerging as a way to solve environmental problems such as reducing greenhouse gas in the long term. (Biogas plant) Introduction and performance testing are underway.

The conventional anaerobic digester used for such biogas energy conversion, as shown in FIG. have.

As a representative example of the anaerobic digester, the UASB reactor was designed by Gutze Lettinga of the Netherlands in the 1970s and obtained successful operation results by applying various high-concentration sewage/wastewater.

The UASB reaction tank is a wastewater distribution device that can evenly distribute wastewater to the front of the reaction tank and separates the generated biogas from liquid (strictly, anaerobic digester treated water)/solid (strictly, microorganism) There is a gas solid separator (GSS) that can do that.

Even now, distribution devices and GSS devices are continuously being improved and supplemented by several researchers and are being applied to actual treatment facilities.

On the other hand, the high-concentration organic wastewater is introduced into the anaerobic digester and then undergoes organic acid fermentation and methane fermentation by anaerobic microorganisms secured in the anaerobic digester to decompose organic matter and convert it to biogas as a final product.

In this anaerobic treatment process, the treatment efficiency is greatly influenced by the reaction conditions, so it is very important to optimize the reaction conditions. Specifically, it is important to maintain the amount of anaerobic microorganisms, the distribution of anaerobic microorganisms in the tank, the temperature for anaerobic microorganisms, PH, etc. in an appropriate state, and even if only some of these reaction conditions are inappropriate, the reaction efficiency is significantly reduced. there was

(001) Republic of Korea Patent No. 10-1918113 (002) Republic of Korea Patent Registration No. 10-0922536 (003) Korean Patent Registration No. 10-0911835

The present invention has been devised to solve the problems of the prior art as described above, and the present invention enables the microorganisms distributed in the reaction tank to be evenly distributed in the reaction tank, so that the anaerobic digestion process is performed evenly over the entire area of the reaction tank. For organic waste treatment This is to provide an anaerobic digestion facility.

And the present invention heats and maintains the temperature in the reaction tank to a temperature suitable for the digestion reaction of anaerobic microorganisms, so that it is heated using the collected biogas fuel, to provide an anaerobic digestion facility for organic waste treatment that improves operational efficiency will do

In addition, the present invention, when a plurality of anaerobic reaction tanks are provided, anaerobic microorganisms can be transferred between the reaction tanks, so that the anaerobic microorganisms can be distributed in an appropriate amount between the rebound tanks. Anaerobic digestion for organic waste treatment It is intended to provide equipment.

And the present invention is to provide an anaerobic digestion facility for organic waste treatment in which the operating efficiency is improved by maintaining the temperature in the reaction tank at a pH suitable for the digestion reaction of anaerobic microorganisms, and minimizing the amount of chemicals used for pH control.

According to a feature of the present invention for achieving the object as described above, the present invention is an intermediate storage tank for storing the inflow water of organic waste to be digested and performing a pre-treatment process; an anaerobic digestion tank receiving the treated water stored in the intermediate storage tank and decomposing organic waste to generate biogas and digested sludge; a transfer pipe for transferring the treated water stored in the intermediate storage tank to the anaerobic digestion tank; a gas storage tank for collecting and storing the biogas generated in the anaerobic digestion tank; a sludge discharge pipe for discharging the digested sludge generated in the anaerobic digestion tank; and a sludge storage tank for storing the digested sludge discharged from the sludge discharge pipe.

Here, the present invention may further include a heating unit for heating the organic waste in the intermediate storage tank and the temperature of the treated water flowing into the anaerobic digestion tank to the optimum temperature for the reaction of anaerobic microorganisms.

And the heating unit, a heating pipe that is piped inside or outside the intermediate storage tank so that the hot water heated by the boiler heats the organic waste of the intermediate storage tank; The hot water discharged from the heating pipe may be configured to include a double pipe heat exchanger to heat the treated water flowing into the anaerobic digestion tank.

In addition, the boiler may generate hot water by using the methane gas contained in the biogas as a fuel.

And the hot water is heated by the boiler, the intermediate storage tank is heated through the heating pipe, the treated water is heated through the double pipe heat exchanger, and then it may be circulated through a closed circulation route introduced into the boiler.

In addition, it may be configured to further include a chemical storage tank for supplying the necessary medicines for the pretreatment process of the influent.

And the intermediate storage tank, withdrawing the influent stored in the intermediate storage tank from the lower portion of the intermediate storage tank, crushing the sludge contained in the influent water may include an intermediate tank crushing pump for pumping to the upper portion of the intermediate storage tank.

In addition, the present invention is a circulating agitator for withdrawing the treated water from the lower part of the anaerobic digester and putting it into the upper part of the anaerobic digester so that the treated water in the anaerobic digester is stirred; A mechanical stirrer for rotating the impeller provided in the anaerobic digestion tank to form a vortex in the anaerobic digestion tank to stir the treated water; may be configured to further include.

And the circulating agitator may include a circulation crushing pump for pulverizing the sludge contained in the treated water drawn from the lower part of the anaerobic digester and pumping it to the upper part of the anaerobic digester.

In addition, when a plurality of anaerobic digesters are provided, the circulation crushing pump pulverizes the sludge contained in the treated water drawn from the lower part of the anaerobic digester and pumps it to the upper part of another adjacent anaerobic digester, between the plurality of anaerobic digesters. It is also possible to distribute the anaerobic microorganisms contained in the sludge.

And the intermediate coarse grinding pump and the circulation grinding pump, a fixed cutter for dividing the solids contained in the inflow by the suction force; It may be configured to include a spiral impeller for pulverizing the solid material cut by the fixed cutter by rotation.

In addition, the mechanical agitator, the motor unit provided outside the anaerobic digestion tank to provide power; a shaft portion extending downward from the motor portion to the inner side of the anaerobic digestion tank to constitute a rotating shaft; It may be configured to include; an impeller unit coupled to the shaft to form a vortex by rotation.

And the mechanical stirrer, a plurality may be provided.

Meanwhile, the present invention may further include a composite stirrer for agitating the treated water of the anaerobic digestion tank by nozzle spraying at least one of the stirring gas and the treated water into the anaerobic digestion tank to form a vortex in the anaerobic digestion tank.

And the composite agitator, a selection valve for selecting the stirring medium by selecting the stirring gas and the treated water; an injection pump for providing injection pressure to the stirring medium selected by the selection valve; It may be configured to include a multi-layer spray nozzle formed in multi-layers so as to spray the stirring medium at different heights in the anaerobic digestion tank.

In addition, the nozzle for each layer of the multi-layer spray nozzle may be provided with a valve for selecting the nozzle to be sprayed.

And the gas storage tank, a methane gas separator for separating the methane gas from the biogas; a methane storage tank for storing the methane gas separated from the methane gas separator; It may be configured to include a carbon dioxide storage tank that is separated from the methane gas separator to store the residual gas containing carbon dioxide as a main component.

In addition, the composite agitator, a biogas supply pipe for branching the biogas flowing into the methane gas separator and providing it to the selection valve; It may be configured to further include a carbon dioxide supply pipe for providing the residual gas containing carbon dioxide as a main component from the carbon dioxide storage tank to the selection valve.

And the complex agitator, may be configured to further include a PH measuring sensor for measuring the PH of the treated water in the anaerobic digestion tank.

In addition, when the PH measurement value of the treated water of the PH sensor is equal to or greater than a preset value, the selection valve uses a residual gas mainly containing carbon dioxide supplied from the carbon dioxide supply pipe as the stirring gas; When the PH measurement value of the treated water of the PH sensor is less than a preset value, biogas supplied from the biogas supply pipe may be used as the stirring gas.

In this case, the preset value of the PH may be 7.1.

The following effects can be expected in the anaerobic digestion facility for organic waste treatment according to the present invention as salvaged above.

That is, in the present invention, while the treated water in the reaction tank is basically stirred with strong force using a mechanical stirrer, the anaerobic microbes that are precipitated with the sludge at the bottom of the reaction tank are pumped to the upper part by using a circulation stirrer, and the anaerobic microbes are evenly distributed. It has the effect of evenly distributing and distributing the microorganisms in the reaction tank by stirring so that a dead flow area in the reaction tank does not occur through a complex stirrer that selects and merges treated water or gas and sprays it to various locations in the reaction tank.

And in the present invention, the boiler is operated using the methane gas collected from the biogas generated in the reaction tank, and the temperature in the reaction tank is heated to a temperature suitable for the digestion reaction of anaerobic microorganisms using the hot water generated accordingly, thereby improving the operating efficiency. It has the effect of providing an eco-friendly anaerobic digestion facility.

In addition, in the present invention, when a plurality of anaerobic reaction tanks are provided, circulating agitators provided in each reaction tank can return anaerobic microorganisms to another reaction tank, so that the anaerobic microorganisms can be properly distributed between the plurality of respective reaction tanks. There is an effect that can distribute the amount of anaerobic microorganisms in a balanced way throughout the digestive system.

In addition, the present invention installs a mechanical stirrer having a structure that penetrates from the outside of the reaction tank into the inside of the reaction tank, so that it is easier to remove, replace, and install the mechanical stirrer than a mechanical stirrer integrally configured with the reaction tank in the reaction tank. Depending on the structure of the type mechanical agitator, there is an effect that the mechanical agitator can be removed or replaced while the reactor is in operation.

In addition, the present invention maintains the temperature in the reaction tank at a pH suitable for the digestion reaction of anaerobic microorganisms, and adjusts the pH by using the biogas composite stirrer generated in the reaction process. This has an improved effect.

1 is an exemplary view showing the configuration of an anaerobic digester for organic waste treatment according to the prior art.
Figure 2 is a block diagram showing the structure of an anaerobic digestion system according to a specific embodiment of the present invention.
3 is an exemplary view showing a specific embodiment of the anaerobic digestion tank constituting the anaerobic digestion facility according to the present invention.
4 is a schematic view showing an example of a pulverization pump constituting an anaerobic digestion system according to the present invention.
5 is an exemplary view showing a specific embodiment of the mechanical agitator constituting the anaerobic digestion system according to the present invention.
6 is an exemplary view showing a specific embodiment of the complex agitator constituting the anaerobic digestion system according to the present invention.
7 is a graph showing the test results of the condition characteristics of the anaerobic digestion process of organic waste.

Hereinafter, an anaerobic digestion facility for organic waste treatment according to a specific embodiment of the present invention will be described with reference to the accompanying drawings.

Before the description, effects, features, and a method of achieving the same of the present invention will become clear in the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

In describing the embodiments of the present invention, if it is determined that a detailed description of a well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted, and the terms to be described later are used in the embodiment of the present invention. As terms defined in consideration of the function of Therefore, the definition should be made based on the content throughout this specification.

Fig. 2 shows the structure of an anaerobic digestion system according to a specific embodiment of the present invention, and Fig. 3 shows a specific embodiment of the anaerobic digestion system constituting the anaerobic digestion system according to the present invention, and Fig. 4 shows the present invention An example of a pulverization pump constituting an anaerobic digestion facility by A specific example of the composite stirrer constituting the is shown, and FIG. 7 is a graph showing the condition characteristic test result of the anaerobic digestion process of organic waste.

First, as shown in FIG. 2, the anaerobic digestion facility according to the present invention is largely an intermediate storage tank 100, anaerobic digestion tank 200, transfer pipe 140, gas storage tank 400, sludge storage tank 530 and heating. It consists of units.

The intermediate storage tank 100 is a portion in which organic waste to be digested is introduced into the influent and stored. At this time, in the intermediate storage tank 100, a pretreatment process by anaerobic microorganisms is performed.

Of course, depending on the type, concentration, amount, etc. of the influent, the intermediate storage tank 100 may be used only as a storage space for simply supplying a certain amount of treated water to the anaerobic digestion tank 200, but preferably the anaerobic digestion tank 200 ) to control the quality of the treated water supplied to the

The pretreatment process is basically a process of decomposing organic wastes by anaerobic microorganisms, and preferably, a sporadic effect process of decomposing the introduced organic wastes into low molecular weight organic compounds is performed.

That is, since the intermediate storage tank 100 also performs the anaerobic digestion process, means such as stirring / chemical input / temperature control to efficiently perform the anaerobic digestion process are involved.

To this end, in the intermediate storage tank 100, the influent water stored in the intermediate storage tank 100 is withdrawn from the lower portion of the intermediate storage tank 100, the sludge contained in the influent water is pulverized, and the intermediate storage tank 100 is pumped to the upper part. It is configured to include a coarse grinding pump (111).

That is, the sludge with a high specific gravity is accumulated in the lower portion of the intermediate storage tank 100, and since the aerobic microorganisms are concentrated in the sludge, the intermediate tank crushing pump 111 pulverizes the sludge in which the anaerobic microorganisms are concentrated to an appropriate size and then again By inputting into the upper part of the intermediate storage tank 100 , the anaerobic microorganisms can be evenly distributed throughout the influent water of the intermediate storage tank 100 .

On the other hand, the intermediate storage tank 100 has a heating unit for controlling the influent temperature to a temperature suitable for the sporadic effect process of anaerobic microorganisms, and a chemical storage tank 120 for storing the drugs injected to increase the decomposition efficiency of anaerobic microorganisms. is provided

And as shown in FIG. 2, the heating unit adjusts the temperature of the influent (organic waste) in the intermediate storage tank 100 and the treated water flowing into the anaerobic digestion tank 200 to the optimum reaction temperature of anaerobic microorganisms according to each process. the heating part.

To this end, the heating unit includes a boiler (not shown) that heats the circulated hot water to heat the influent and treated water of the intermediate storage tank 100 while circulating the arranged piping, and the intermediate storage tank 100 inside or outside. A heating pipe 130 for piping and hot water heated by a boiler to heat the organic waste of the intermediate storage tank 100, and a process in which hot water discharged from the heating pipe 130 is introduced into the anaerobic digestion tank 200 It is configured to include a double tube heat exchanger 150 to heat the water.

Here, the hot water is heated by the boiler, the intermediate storage tank 100 is heated through the heating pipe 130 , and the treated water is heated through the double tube heat exchanger 150 , and then to the boiler. It is circulated through the pipe of the inflow closed circulation route.

And, since the hot water is circulated through a closed circulation route and does not come into direct contact with influent or treated water, various additives capable of increasing thermal conductivity may be included, or various fluids other than water may be applied.

In addition, various boilers may be applied to the boiler, but preferably, it may be a boiler using methane gas contained in the biogas as a fuel. According to this, since the boiler can supply and receive fuel for heating itself, it is possible to reduce operating costs and environmental pollution due to the use of fossil fuels.

On the other hand, the heating pipe 130 is piped in contact with the outside or inside the intermediate storage tank 100, and may be overlapped in a curved shape so that the contact area is enlarged.

In addition, the double pipe heat exchanger 150 is indirectly contacted in the pipe in which the hot water and the treated water are separated to heat the treated water by heat exchange.

Of course, although not shown, the intermediate storage tank 100 may be provided with a mechanical stirring facility for stirring the stored inflow water by rotating the mechanical impeller.

Meanwhile, the treated water pretreated in the intermediate storage tank 100 is transferred to the anaerobic digestion tank 200 by a transfer pipe 140 . For this purpose, a transfer pump 142 may be provided in the singi transfer pipe.

Hereinafter, the anaerobic digestion tank 200 that decomposes the treated water, which is the pre-treated organic waste, through an anaerobic digestion process and produces biogas, will be examined in detail.

As described above, the anaerobic digestion tank 200 is a place where pre-treated water is introduced to decompose the anaerobic digestion process, and biogas including methane used as a biofuel is produced through this process.

Accordingly, in the anaerobic digestion tank 200, as shown in FIG. 3, a gas storage tank 400 that collects and stores the biogas generated in the anaerobic digestion process, and sludge, which is a by-product generated in the digestion process (end of life). A sludge storage tank 530 and a sludge discharge pipe 520 for discharging anaerobic microorganisms) are provided.

Of course, the sludge discharge pipe 520 may be provided with a sludge discharge pump 510 capable of sucking the discharged sludge.

On the other hand, the anaerobic digestion tank 200 is provided with stirring means to effectively operate the anaerobic digestion process, the stirring means, as shown in FIG. It can be divided into a composite stirrer (230).

First, the circulation agitator 210 withdraws the treated water containing sludge from the lower part of the anaerobic digester 200 and puts it into the upper part of the anaerobic digester 200 so that the treated water in the anaerobic digester is stirred.

At this time, rather than the effect of mixing the treated water itself, the agitation grinds the sludge concentrated in the lower part of the anaerobic digester 200 and injects it into the upper part of the anaerobic digester 200, so that the anaerobic microorganisms are evenly distributed in the anaerobic digester 200. The effect of distributing it is great.

To this end, the circulating agitator 210 is configured to include a circulating crushing pump 211 and a circulating agitating pipe 213 .

The circulation grinding pump 211 pulverizes the sludge contained in the treated water withdrawn through the circulation and agitation pipe 213 from the lower part of the anaerobic digestion tank 200, and moves the circulation stirring pipe 213 to the upper part of the anaerobic digestion tank 200. ) is pumped through.

On the other hand, a general anaerobic digestion facility is provided with a plurality of anaerobic digestion tanks 200, and the circulation crushing pump 211 pulverizes the sludge contained in the withdrawn treated water when a plurality of the anaerobic digestion tanks 200 are provided, It can be transferred to the upper part of another adjacent anaerobic digester.

Of course, in this case, as shown in FIG. 2, the circulation stirring pipe is installed in a cross-arranged arrangement with a plurality of anaerobic digestion tanks.

Through this, in the present invention, it is possible to cross-distribute the anaerobic microorganisms included in the sludge between the plurality of anaerobic digestion tanks, thereby allowing the total amount of microorganisms in the anaerobic digestion tanks of the entire anaerobic digestion facility to be controlled.

On the other hand, the intermediate coarse crushing pump 111 and the circulation crushing pump 211 perform a common function of crushing and inputting the sucked sludge.

To this end, the intermediate coarse grinding pump 111 and the circulation grinding pump 211 are, as shown in FIG. 4, a fixed cutter (FC) that divides the solids contained in the inflow by suction force, and the fixed cutter (FC) ) is configured to include a spiral impeller (SP) that crushes the cut solid by rotation.

The fixed cutter (FC) has a fixed blade attached to it, and the fluid is crushed and transferred at the same time through between the parallel and symmetrical plates of the impera, so that it is possible to transfer the solid material without clogging.

The spiral impeller (SP) is made of stainless steel (SCS13), and the shape of the blade is preferably formed in a spiral as shown in FIG. 4 because clogging must be prevented along with a crushing function.

On the other hand, the mechanical stirrer 220 rotates the impeller provided in the anaerobic digestion tank 200 to form a vortex in the anaerobic digestion tank 200 to stir the treated water. For this purpose, the mechanical stirrer 200 is a motor unit 221 , and a shaft portion 222 and an impeller portion 223 are included.

The motor unit 221 is provided outside the anaerobic digestion tank 200 to provide power.

In addition, the shaft portion 222 extends from the motor portion 221 and extends downwardly inside the anaerobic digestion tank 200 to constitute a rotation shaft.

In addition, the impeller part 223 is coupled to the end of the shaft part 222 to form a vortex by rotation.

A typical mechanical agitator is built into the upper and lower parts of the anaerobic digester. In the case of repairing or replacing the mechanical agitator installed in this way, stop the operation of the anaerobic digester, and then discharge the treated water in the anaerobic digester (lower part of the digester) ), remove and replace and repair the stirrer.

Therefore, there is a problem in that when the mechanical agitator is repaired/replaced, an operation vacancy of the fire extinguishing facility is generated, and thus the operating efficiency of the facility is lowered.

Accordingly, the present invention installs the motor unit 221 and the coupling joint part, which is the main maintenance target of the mechanical agitator, outside the anaerobic digester 200, so that most maintenance/repair of the mechanical agitator 220 without stopping the operation of the anaerobic digester to be able to perform

In addition, a plurality of mechanical agitators 220 installed in the up/down inclination direction may be installed along the outer circumferential surface of the anaerobic digestion tank 200, and thus, there is an excellent effect in terms of installation space utilization.

Next, the composite stirrer 230 is a device for agitating the treated water in the anaerobic digestion tank 200 by spraying a fluid and a gas or a mixture thereof to form a vortex in the anaerobic digestion tank 200 .

Here, the composite stirrer 230 should select a fluid or gas (gas) to be used for vortex formation, and select a spray position for effective vortex formation in treated water.

To this end, the composite stirrer 230 is, as shown in FIGS. 3 and 6, a selection valve 233 for selecting a fluid or gas to be used as a stirring medium, and a stirring medium selected by the selection valve 233. It is configured to include an injection pump 235 for providing injection pressure, and a multi-layer injection nozzle 236 formed in multiple layers to inject the stirring medium at different heights in the anaerobic digestion tank 200 .

At this time, it is preferable that the multi-layer spray nozzle 236 is provided with a valve V for selecting the nozzle to be sprayed on the nozzle for each layer of .

In particular, when gas is used as the stirring medium, the stirring medium forms fine bubbles by the nozzle and is sprayed into the treated water to increase the stirring effect.

As described above, the selection valve 233 selects the stirring medium. When a liquid is used as the stirring medium, the processing water stored in the anaerobic digestion tank is used as the stirring medium.

Therefore, a pipe for withdrawing and providing treated water from the anaerobic digestion tank is connected to the sorting valve 233. Since it is preferable that the withdrawn treated water does not contain sludge, it is preferable that the treated water is withdrawn from the upper layer (not shown). ).

On the other hand, when treated water is used as the stirring medium, since sludge is generally included, gas is used as the stirring medium to prevent nozzle clogging.

However, the gas used as a stirring medium may have a significant effect on the digestion (decomposition) efficiency of anaerobic microorganisms depending on the type of gas.

Specifically, looking at the digestion process of anaerobic microorganisms in the anaerobic digestion tank,

C ₆ H ₁₂ O ₆ + 2H ₂ O -> CH ₃ COOH + 2CO ₂ + 4H ₂ + 4ATP -> CO ₂ + 3CH ₄

By a reaction such as , organic matter is reduced to methane and carbon dioxide, and sulfides and the like are produced incidentally in this process.

On the other hand, the digestion efficiency of anaerobic microorganisms is greatly influenced by temperature and PH. In the case of PH, it is known that the optimal range of an anaerobic process is pH 6.5 to 7.5, and the optimal range is pH 7.0 to 7.2.

And the anaerobic digestion tank measures the PH of the treated water in the digester, and it is common to adjust the PH in the digester by adding a chemical to keep the optimal range.

On the other hand, in the composite stirrer 23 according to the present invention, when gas is used as a stirring medium, a gas to be used can be selected.

At this time, the gas used as the stirring medium can be divided into two types. First, biogas generated and collected in the anaerobic digestion process in the anaerobic digestion tank 200, and second, carbon dioxide from which methane is extracted from the biogas am.

That is, when the collected biogas is used as a gas as a stirring medium, the biogas is re-injected and dissolved in the treated water in the digester, so that there is no change in the PH in the treated water. However, in this case, since the biogas is dissolved in the treated water, there is a disadvantage in that the amount of biogas collected, that is, the production of methane, which is a biofuel, is reduced.

In order to prevent this, when methane is extracted from the collected biogas as a gas as a stirring medium and a residual gas mainly of carbon dioxide is used, there is a problem in that the PH is lowered due to oxidation as the carbon dioxide is dissolved in the treated water.

Specifically, as shown in FIG. 7 , as the partial pressure of CO2 increases, the PH can be seen to decrease. Specifically, the PH is lowered by increasing the concentration of hydrogen ions in the water through the following process.

(1) CO2 (carbon dioxide) + H2O (water) => H2CO3 (carbonic acid)

(2) H2CO3 (carbonic acid) => H+ (hydrogen ion) + HCO3- (hydrogen carbonate ion, bicarbonate ion)

(3) HCO3- (hydrogen carbonate ion, bicarbonate ion) => H+ (hydrogen ion) + CO3 2- (carbonate ion)

Accordingly, in the present invention, by measuring the PH of the treated water in the anaerobic digester 200, when the PH measurement value is greater than a specific value (preset value), the remaining gas containing carbon dioxide as a main component as the stirring medium is used, When the pH measurement value is less than a preset value, the biogas collected by the stirring medium is used.

In this case, the preset PH reference value may be 7.1, which is the optimal PH, as described above, but may be set differently according to the operating environment of the facility.

That is, in adjusting the PH of the treated water in the digester by using carbon dioxide discharged as a by-product in the digestion process as a stirring medium (gas) for stirring the digester, the rise in PH can be controlled without the use of chemicals, so operating costs In addition to securing the reduction and efficiency of energy consumption, it is possible to minimize environmental pollution by reducing the amount of carbon dioxide generated by the operation of anaerobic digestion facilities.

To this end, the gas storage tank 400 according to the present invention is configured to include a methane gas separator 410 , a methane storage tank 420 and a carbon dioxide storage tank 430 .

The methane gas separator 410 is a device for separating methane (CH4) gas from the collected biogas, and various types of separation facilities may be applied.

And the methane storage tank 420 is a storage tank for storing the methane gas separated from the methane gas separator 410 to be used as a biofuel.

In addition, the carbon dioxide storage tank 430 is a storage tank for storing residual gas mainly composed of carbon dioxide remaining after methane gas is separated from the collected biogas, and the residual gas from which sulfides, which may cause toxicity, have been removed. can be saved.

And the composite agitator 230 is a biogas supply pipe 231 for branching the biogas flowing into the methane gas separator 410 and providing it to the selection valve 233, and the carbon dioxide storage tank 430 from the carbon dioxide. It is configured to include a carbon dioxide supply pipe 232 for providing the residual gas with the main component to the sorting valve 233, so that the gas used as the stirring medium is collected from biogas or carbon dioxide-centered residual gas from which methane has been removed. Allows you to choose either one.

In addition, the complex agitator 230 is installed in the anaerobic digestion tank 200, it is preferable to include a PH measuring sensor 237 for measuring the PH of the treated water.

The right of the present invention is not limited to the above-described embodiments, but is defined by the claims, and those skilled in the art can make various modifications and adaptations within the scope of the claims. it is self-evident

The present invention relates to an anaerobic digestion facility for organic waste treatment that processes organic waste using anaerobic microorganisms in an intermediate storage tank and anaerobic digestion tank to produce sludge and methane gas. According to the present invention, the treated water in the reaction tank is basically While stirring with strong force using a mechanical stirrer as It has the effect of evenly distributing the microorganisms in the reaction tank by stirring so as not to generate a dead flow area in the reaction tank through a composite stirrer that sprays to various locations in the reaction tank.

100: intermediate storage tank 110: intermediate tank circulation pipe
111: intermediate tank crushing pump 120: chemical storage tank
130: heating pipe 140: transfer pipe
142: transfer pump 150: double pipe heat exchanger
200: anaerobic digestion tank 210: circulation type exchanger
211: circulation grinding pump 213: circulation stirring pipe
220: mechanical stirrer 221: motor unit
222: shaft 223: impeller
230: composite stirrer 231: condensed gas pipe
232: carbon dioxide supply pipe 233: sorting valve
235: injection pump 236: multi-layer injection nozzle
237: PH measuring sensor 400: gas storage tank
410: methane separator 420: methane storage tank
430: carbon dioxide storage tank 510: sludge discharge pump
520: sludge discharge pipe 530: sludge storage tank

Claims (16)

an intermediate storage tank for storing the inflow water of organic waste to be digested and performing a pre-treatment process;
an anaerobic digestion tank receiving the treated water stored in the intermediate storage tank and decomposing organic waste to generate biogas and digested sludge;
a transfer pipe for transferring the treated water stored in the intermediate storage tank to the anaerobic digestion tank;
a gas storage tank for collecting and storing the biogas generated in the anaerobic digestion tank;
a sludge discharge pipe for discharging the digested sludge generated in the anaerobic digestion tank;
a sludge storage tank for storing the digested sludge discharged from the sludge discharge pipe; and
It comprises a composite stirrer for agitating the treated water of the anaerobic digestion tank by nozzle spraying at least one of the stirring gas and the treated water into the anaerobic digestion tank to form a vortex in the anaerobic digestion tank:
The composite stirrer,
a selection valve for selecting a stirring medium by selecting the stirring gas and the treated water;
an injection pump for providing injection pressure to the stirring medium selected by the selection valve; and
Anaerobic digestion system for organic waste treatment, characterized in that it comprises a multi-layered spray nozzle formed in multi-layers so that the stirring medium can be sprayed at different heights in the anaerobic digestion tank.
The method of claim 1,
Anaerobic digestion facility for organic waste treatment, characterized in that it further comprises a heating unit for heating the temperature of the organic waste in the intermediate storage tank and the treated water flowing into the anaerobic digestion tank to the optimum reaction temperature of anaerobic microorganisms.
3. The method of claim 2,
The heating unit is
a heating pipe that is piped inside or outside the intermediate storage tank so that the hot water heated by the boiler heats the organic waste of the intermediate storage tank;
Anaerobic digestion facility for organic waste treatment, characterized in that it comprises a double tube heat exchanger for heating the treated water flowing into the anaerobic digestion tank by the hot water discharged from the heating pipe.
4. The method of claim 3,
The boiler is
Anaerobic digestion facility for organic waste treatment, characterized in that generating hot water by using methane gas contained in the biogas as a fuel.
5. The method of claim 4,
The hot water is
It is heated by the boiler, the intermediate storage tank is heated through the heating pipe, the treated water is heated through the double tube heat exchanger, and then circulated through a closed circulation route introduced into the boiler For organic waste treatment Anaerobic digestion system.
6. The method of claim 5,
Anaerobic digestion facility for organic waste treatment, characterized in that it further comprises a chemical storage tank for supplying the necessary chemicals for the pretreatment process of the influent.
6. The method of claim 5,
The intermediate storage tank,
Anaerobic digestion facility for organic waste treatment, characterized in that it comprises an intermediate tank crushing pump that withdraws the influent stored in the intermediate storage tank from the lower portion of the intermediate storage tank, pulverizes the sludge contained in the influent water and pumps it to the upper intermediate storage tank .
8. The method of claim 7,
a circulation-type stirrer that withdraws the treated water from the lower part of the anaerobic digester and puts it into the upper part of the anaerobic digester to stir the treated water in the anaerobic digester;
Anaerobic digestion facility for organic waste treatment, characterized in that it further comprises; a mechanical stirrer for rotating the impeller provided in the anaerobic digestion tank to form a vortex in the anaerobic digestion tank to stir the treated water.
9. The method of claim 8,
The circulatory stirrer,
Anaerobic digestion facility for organic waste treatment, characterized in that it comprises a circulation crushing pump for pulverizing the sludge contained in the treated water withdrawn from the lower part of the anaerobic digester and pumping it to the upper part of the anaerobic digester.
10. The method of claim 9,
The circulation crushing pump,
When a plurality of anaerobic digestion tanks are provided,
The sludge contained in the treated water withdrawn from the lower part of the anaerobic digester is pulverized and pumped to the upper part of another adjacent anaerobic digester to distribute the anaerobic microorganisms contained in the sludge between the plurality of anaerobic digesters. Organic waste treatment, characterized in that anaerobic digestion system for
10. The method of claim 9,
The intermediate coarse grinding pump and the circulation grinding pump,
a fixed cutter that divides the solids contained in the inflow by suction force;
Anaerobic digestion system for organic waste treatment, characterized in that it comprises a spiral impeller for grinding the solid material cut by the fixed cutter by rotation.
12. The method of claim 11,
The mechanical stirrer,
a motor provided outside the anaerobic digestion tank to provide power;
a shaft portion extending downward from the motor portion to the inner side of the anaerobic digestion tank to constitute a rotating shaft;
Anaerobic digestion facility for organic waste treatment, characterized in that it comprises a; impeller unit coupled to the shaft to form a vortex by rotation.
13. The method of claim 12,
The mechanical stirrer,
Anaerobic digestion facility for organic waste treatment, characterized in that a plurality is provided.
delete delete The method of claim 1,
In the nozzle for each layer of the multi-layer spray nozzle,
Anaerobic digestion system for organic waste treatment, characterized in that provided with a valve that allows the nozzle to be injected can be selected.

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