KR101114972B1 - Divice and method of anaerobic digestion using liquid impulse mixing - Google Patents

Abstract

PURPOSE: A liquid impulse-mixed anaerobic digestion apparatus and a method for the same are provided to stably operate a digestion bath without a driving part for a mixing operation and to reduce power required for the mixing operation. CONSTITUTION: An anaerobic digestion apparatus includes a digestion bath(1), a compensation bath(2), a liquid pipe(5), and an impulse pump(6). Organic materials are introduced into the digestion bath through an inlet. The compensation bath includes a space capable of being filled with liquid. The liquid pipe connects the bottom parts of the compensation bath and the digestion bath. The impulse pump is installed at the liquid pipe and introduces liquid from the compensation bath to the digestion bath. Upward flow of liquid is induced in the digestion bath according to the liquid introduction toward the digestion bath. Downward flow of liquid is induced in the digestion bath according to the liquid level difference of the digestion bath and the compensation bath. The organic materials in the digestion bath are mixed.

Description

Liquid shock-mixed anaerobic digestion apparatus and its method {DIVICE AND METHOD OF ANAEROBIC DIGESTION USING LIQUID IMPULSE MIXING}

The present invention relates to a liquid-impact mixed anaerobic digestion apparatus and a method thereof, and more specifically, to aerobic digestion of organic substances contained in wastewater or liquid waste, a tower-type digester equipped with a perforated plate and a correction tank are installed together from a calibration tank. Induces anaerobic digestion by inducing liquid impact mixture without installing a separate mechanical agitator in the digester by inducing the upstream flow of the liquid through the liquid supply of the liquid and inducing the downstream flow of the liquid by the difference of the water level between the calibration tank and the digester. It relates to a liquid shock-mixed anaerobic digestion apparatus and a method thereof.

Liquid wastes such as food waste, sewage sludge, or livestock wastewater contain high concentrations of dissolved or particulate organic matter, which is expensive to treat. The treatment of these organics with anaerobic bacteria by converting them into biogas is more economical, and the interest in anaerobic digesters is increasing because the methane of the generated biogas can be recovered and recycled as renewable energy.

Such anaerobic digesters generally have a mechanical or physical mixing system that uniformly mixes these two materials to sufficiently digest organic matter that enters anaerobic bacteria into a closed digester that is blocked from air.

However, anaerobic digesters have a limited range of sizes and concentrations of particulate matter that can be introduced, depending on the type and mix of digesters. In particular, a device for anaerobic digestion of high concentrations of particulate organic matter is introduced into a closed tank according to the ratio of diameter and height, especially in a conventional digester having a diameter larger than the height, as a mechanical mixing method using a propeller stirrer or a paddle stirrer. Since the organic materials and bacteria are not uniformly mixed with each other, the contact efficiency between the two materials is low and the material transfer rate is very low. Therefore, the rate of digestion of organic matters by anaerobic bacteria is low, so the loading rate of inflow organic matters per unit volume is 2-3 kgVS / m ³ × d. low.

In addition, the anaerobic digester with a mechanical stirrer requires a plurality of stirrers to be installed because of the large capacity of the digester, and thus the power consumption is high, and as a moving part installed inside the digester, the digester is maintained, which is likely to fail. There are many problems with management. In addition, the digester of the mechanical stirrer is not only large in capacity, but a larger required area is required because the corresponding stirrer is generally low in order to obtain an optimum mixing efficiency.

The present invention has been made to solve the above problems, the object is that the anaerobic bacteria and the residual organic mixture mixture at high speed through the holes of the perforated plate installed in the tower digester without a mechanical agitator operated separately in the anaerobic digester While mixing the perforated plates, the organic material and anaerobic bacteria flowing into the bottom of the digester are completely mixed to increase the rate of digestion of organic matter and biogas, decrease the power required for mixing, and digestible organic matter per unit volume. The present invention provides an anaerobic digestion apparatus and method for increasing the load to reduce the digester capacity and the required area.

According to one aspect of the invention, the digester through which the organic matter is introduced through the inlet; A calibration tank having a space in which liquid can be filled; A liquid pipe connected to the bottom of the digester from the bottom of the calibration tank; And a shock pump installed in the liquid pipe to introduce liquid from the correction tank into the digester. It includes, and induces an upstream flow of the liquid in the digester in accordance with the liquid inflow into the digester through the impact pump and induces the flow of liquid in the digester downflow according to the level difference between the digester and the correction tank to the organic material in the digester It provides an anaerobic digestion apparatus, characterized in that the mixing.

Preferably, the digester is characterized in that at least one porous plate having a plurality of holes is installed in a horizontal state.

Preferably, the holes of the porous plate are formed by uniformly perforated on the surface of the porous plate, each hole has a diameter of 30mm to 50mm, characterized in that the interval between the center of the hole is 80mm to 100mm.

Preferably, a cover supported by at least two supports is provided on the hole of the porous plate.

Preferably, the gap between the hole and the cover of the porous plate is 1.5 to 2.5 times the diameter of the hole, the diameter of the cover is characterized in that 1.3 to 1.8 times the diameter of the hole.

Preferably, the cover is characterized in that it is formed in the shape of a dome protruding convex toward the upper side.

Preferably, the digester is characterized in that the height is at least two times larger than the diameter.

Preferably, the biogas storage space is formed on the digester.

Preferably, the impact pump is operated to induce an upstream flow of the liquid in the digester, characterized in that for opening the flow path so that the liquid in the digester flows into the correction tank during the downflow of the liquid in the digester.

Preferably, the correction tank is attached to the upper portion of the digester, characterized in that installed separately from the digester at the same height as the upper position of the digester.

Meanwhile, according to another aspect of the invention, (a) supplying an organic material to the digester; (b) introducing a liquid in the correction tank through an impact pump through a lower portion of the digester to induce an upward flow of liquid in the digester; And (c) stopping the operation of the impact pump and inducing a downward flow of liquid in the digester according to the difference in water level between the digester and the calibration tank; It provides an anaerobic digestion method comprising a.

Preferably, the at least one porous plate having a plurality of holes in the digester is installed in a horizontal state to induce impact mixing of the liquid moving in the digester.

Preferably, the cover is supported by at least two supports on the holes of the porous plate to induce impact mixing of the liquid moving in the digester.

Preferably, the impact pump is operated to induce an upstream flow of the liquid in the digester, characterized in that for opening the flow path so that the liquid in the digester flows into the correction tank during the downflow of the liquid in the digester.

According to the present invention, there is no mechanical stirring device inside the digestive tank of the anaerobic digester and the liquid is returned by the operation of the shock pump placed between the digester and the calibration tank and the shock pump is stopped according to the water level difference between the two tanks. The specific surface area where anaerobic bacteria and incoming organics come in contact with the anaerobic bacteria as liquids pass through the holes of the perforated plates at high flow rates with upstream and downstream flows in the digester, leading to ideal complete mixing. Since this is extended to increase the material transfer rate between them, the digestibility of the organic material is increased, and further, the effect of increasing the amount of biogas generated can be obtained.

In addition, the shock pump is operated for a short time to cause impact mixing in the digester, and the non-power mixing due to the backflow in the digester due to the level difference between the digester and the calibration tank is repeatedly performed. It can be reduced, and there is no moving part for mixing in the digester, so that the digester can be stably operated and easy to maintain.

In addition, due to the improved digestion efficiency according to the increase in the material transfer rate between the anaerobic bacteria and organic matter in the digester, the load of the influent organic matter that can be digested in the digester is significantly increased, so that the capacity of the digester can be reduced. Since the digester structure according to the tower type is more than twice the height than the diameter, there is also an effect that can significantly reduce the required area.

1 is a cross-sectional view of the liquid impact mixed anaerobic digestion apparatus according to the present invention.
Figure 2 is a bottom view of the porous plate from the bottom in the liquid impact mixed anaerobic digestion apparatus according to the present invention.
3 is a view for explaining the hole and its cover structure in the porous plate according to the present invention.

Hereinafter, with reference to the accompanying drawings, an embodiment of the liquid impact mixed anaerobic digestion apparatus according to the present invention will be described in more detail.

1 is a cross-sectional view of a liquid shock-mixed anaerobic digester for converting organic matter into a biogas containing methane using anaerobic bacteria, and FIGS. 2 and 3 are details of a porous plate which plays an important role in causing liquid impact mixing in a digester. It is also.

In the fire extinguishing device according to the present invention, at least one porous plate (3) horizontally causing impact mixing of liquids for contact with anaerobic bacteria and organic matter is installed horizontally inside the tower type digester (1) having a height greater than two times the diameter. , A calibration tank (2) for storing the liquid necessary to induce liquid impact mixing between the porous plates (3) is separated around the upper edge of the digester (1) and has the same capacity as the digester (1) It is provided in, between the bottom of the correction tank (2) and the bottom of the digester (1) may be composed of a liquid pipe (5) and an impulse pump (Impulse Pump) that can transfer the liquid.

As shown in FIG. 1, the digester 1 is formed in a tower shape having a height greater than twice as large as a diameter, and may be made of metal or concrete. The upper part of the digester (1) is provided with a storage space (4) of the generated biogas, the inlet (7) for supplying the organic material to be digested is located at the bottom of the digester (1), anaerobic digestion generated after the organic material digestion The outlet 8 through which the sludge and the residual organic matter mixture is discharged may be at the same position as the surface of the upper part of the digester 1, and an electric valve 9 may be attached to block and open the outlet 8 in the outlet pipe. have.

In the example shown, along the edge of the top of the digester 1 lies a calibration tank 2 which is completely separated from the digester 1 and located at the same water level, the effective capacity of which is It is preferable that it is at least 1.5% or more with respect to the effective capacity, and it is preferable to always make the same material as the digester (1). And such a correction tank (2) may be isolated independently attached to the edge of the upper portion of the digester (1) as shown in the figure or otherwise completely separated and positioned independently.

The correction tank (2) and the digester (1) are separated from each other, but are connected to the liquid pipe (5) for liquid transfer between the bottom of the correction tank (2) and the bottom of the digester (1), Through this liquid pipe 5, one impact pump 6 capable of transferring the liquid in the correction tank 2 to the bottom side of the digestion tank 1 can be placed. This shock pump (6) is a pump having a function that the liquid can flow quickly in the reverse direction by opening the flow path when not in operation, the liquid flows back to the correction tank (2) as quickly as the amount of liquid transferred to the digester (1) The liquid pipe 5 may be open at all times so that can pass through.

In addition, the perforated plate 3 inside the digester 1 is installed to maintain a horizontal posture and may be installed at a predetermined height in at least one stage, preferably two or more stages in the digester 1. .

This porous plate 3 may be made of a metal or synthetic resin resistant to corrosion. As illustrated in FIG. 2, a plurality of holes 13 may be formed in the porous plate 3.

Looking in more detail with respect to the hole 13 of the porous plate 3, the diameter of the hole 13 in the porous plate 3 may be 30mm to 50mm, the distance between each hole 13 is the porous plate 3 It is preferable that the organic material is uniformly arranged while forming an equilateral triangle with each other within 80 mm to 100 mm so as not to deposit the organic material on the layer.

In the porous plate 3, the covers 15 may be provided at the upper portions of the holes 13, respectively. Referring to FIG. 3, a cover 15 supported by the support 14 may be fixedly installed on the hole 13 of the porous plate 3.

Here, the support 14 is provided with at least two or more support 14 to pass the organic mixture liquid to form a flow path, the cover 15 installed on the upper portion of the support 14 is convex toward the upper side. It may be formed in the form of a protruding dome. The structure of the cover 15 passes through the hole 13 at the lower portion of the liquid mixture (upflow) is made to pass through the support 14, and the impact mixture is passed again at a high flow rate through the cover 15 It is to be made, it is possible to naturally lead the liquid (downflow) flowing back to the hole 13 from the top through the dome-shaped cover 15 to the lower hole (13).

That is, in the upflow flow 11, the first impact mixing is performed while the liquid passes through the hole 13 at a high flow rate, and the liquid passing through the hole 13 hits the cover 15 and the support 14. Passing between the passing of the cover between the second impact mixing is made.

At this time, the hole 13 and the cover 15 and the gap of the porous plate 3 may be 1.5 times to 2.5 times the diameter of the hole 13, and preferably 2 times is advantageous for the secondary impact mixing. In addition, the diameter of the cover 15 may be 1.3 times to 1.8 times the diameter of the hole 13, preferably 1.5 times is advantageous for secondary impact mixing.

Therefore, when the shock pump 6 is operated, the liquid stored in the correction tank 2 is pumped to the bottom of the digester 1, and the holes 13 drilled in each porous plate 3 as the upflow flow 11 by the pumped flow rate. Primary liquid shock mixing is carried out while passing through a predetermined gap between the cover (15) placed at a certain height upward from this hole (13), and also the secondary liquid shock mixing to produce a secondary liquid shock mixing (1) ) Increase the specific surface area of anaerobic bacteria in contact with organics. At this time, the water level of the correction tank (2) is lowered as the liquid is transferred, while the water level inside the digester (1) rises by a corresponding amount, the level difference is generated between the digester (1) and the correction tank (2).

In addition, when the shock pump 6 stops after the shock pump 6 sufficiently transfers the liquid of the correction tank 2 to the digester 1 to cause shock mixing, the digester 1 and the correction tank 2 Due to the water level difference generated between), the liquid rising from the digester 1 flows back to the correction tank 2 of the lowered water level. The liquid flowing back from the digester 1 until the water level in the digester 1 and the calibration tank 2 is naturally equal causes impact mixing between the porous plates 3 in the downflow stream 12.

As described above, the present invention repeatedly generates the impact mixture in the digester 1 at regular time intervals by the operation of the shock pump 6 and the non-power caused by the level difference between the digester 1 and the correction tank 2. It is characterized by inducing complete mixing in the interior.

That is, the inflow of the organic material to be digested in the anaerobic digestion apparatus flows into the bottom of the digester 1 and passes through each of the porous plates 3 of the digester 1 by the operation of the shock pump 6 and the level of the stop. Repetitive impact mixture of upstream and downstream flows to be digested in contact with anaerobic bacteria and discharged to the upper part of digestion tank (1), so that the introduced organic matter stays in digestion tank (1) for at least as long as the residence time of Can be discharged.

Now, the anaerobic digestion method using the extinguishing device according to the present invention will be described in detail.

In order to convert the organics into methane-containing biogas using anaerobic bacteria, the organics are injected discontinuously or continuously depending on the inflow through the inlet 7 at the bottom of the anaerobic digester 1.

In the case of the anaerobic digestion apparatus according to the present embodiment, the impact pump 6 pumps the liquid in the calibration tank 2 placed on the digester 1 so that the organic material injected into the digester 1 is sufficiently mixed with the anaerobic bacteria. When the pump is pumped to the bottom of the digester 1, the level of the digester 1 rises and the level of the correction tank 2 decreases.

At this time, the impact pump 6 may have a pumping capacity to transfer the flow rate stored in the correction tank (2) to the digester (1) for less than 0.5 minutes to 1 minute, and when the pumping of the given flow rate during this time is automatically It will stop working.

During the time that the impact pump 6 is operated, the liquid in the digester 1 impacts primarily through the holes 13 of the porous plate 3 disposed in the digester 1 with an upflow flow 11. Are mixed. Then, it collides with the cover 15 installed and fixed on the hole 13 and passes through the covers 15 at high flow rates, and simultaneously causes liquid impact mixing on each of the porous plates 3 at the same time. Due to such impact mixing, the dead zone does not occur in the digester 1, and it is completely mixed with anaerobic bacteria and the introduced organic material, thereby maximizing the specific surface area and mass transfer that they can contact to improve organic digestibility. have.

On the other hand, when the operation of the shock pump 6 is stopped, the liquid in the digester 1 flows back to the correction tank 2 due to the difference in the level of the water level rising from the digester 1 and the level of the lowered level of the correction tank 2. . At this time, the liquid in the digester 1 passes through the holes 13 and the lids 15, which are drilled in the porous plate 3, which is installed in multiple stages by the downflow stream 12, and the liquid under each of the porous plates 3 at the same time. Impact mixing occurs.

The mixing that occurs while being flowed back by the non-power level difference is about 4 times longer because of the slower flow rate than when the impact pump 6 is operated, and no power is consumed for mixing.

In the embodiment of the present invention, the liquid impact mixture in the digester 1 is about 2 to 3 minutes by the upstream flow 11 by the impact pump 6 and the downflow stream 12 according to the non-power level difference. After the mixing is completed, the anaerobic reaction of the anaerobic bacteria and the introduced organic matters which are already mixed in the digester 1 proceeds actively for about 10 minutes. During this anaerobic reaction, organic matter is continuously introduced and accumulated in the digestion tank, so that uniform mixing is required in the digestion tank again, and the impact pump 6 is operated again so that the liquid impact mixing occurs according to the aforementioned method.

As described above, the impact mixing using the impact pump 6 and the non-powered impact mixing according to the water level difference and the anaerobic digestion reaction in the stopped state may be repeatedly performed in 110 to 120 cycles for one day. . According to this cycle, the impact pump 6 is operated within a maximum of about 2 hours per day so that the power consumed for mixing in the digester 1 can be significantly lowered.

When the liquid in the correction tank (2) is sent to the digester (1) by the operation of the shock pump (6) and the internal water level is increased, the pumping flow rate of the shock pump (6) through the outlet 8 in the upper part of the digester (1) Since it can escape outside, the electric valve 9 attached to the outlet pipe is closed simultaneously with the operation of the impact pump 6. The electric valve 9 stops the operation of the shock pump 6, and the rising level of the digester 1 flows back to the lowered level of the correction tank 2, and is opened again when the level between the two tanks is the same, so that the anaerobic digestion sludge and The mixed liquid of the residual organic matter is discharged out of the digester 1 through the outlet 8.

Thus, the electric valve 9 of the outlet port is always closed for about 2-3 minutes during the operation of the impact pump 6 in the digester 1 and the impact mixing caused by the water level difference force, so that the anaerobic digestion sludge and the remaining organic matter The mixed liquid will not be discharged. Therefore, the electric valve 9 attached to the outflow pipe according to the present embodiment may be closed every one cycle of the impact mixing and anaerobic digestion reaction, and the opening may be repeated up to 120 cycles per day.

Biogas generated by anaerobic digestion of organic matter in the anaerobic digester is collected in the digester (1) upper biogas storage space (4) and is discharged to a biogas storage tank (not shown) separately installed through the biogas outlet (10). .

In addition, until the organic material to be digested in the anaerobic digestion apparatus according to the embodiment of the present invention flows into the bottom of the tower type digester 1 and is discharged to the outlet 8 located in the upper part of the digester, in particular, a particulate organic material having a high density of particles. Are repeatedly moved up and down the two or more stages of the perforated plates 3 in the digester 1 along the upflow 11 and the downflow stream 12 causing liquid impact mixing between the two or more stages of the perforated plates 3. Therefore, it is possible to maximize the extinguishing rate of the organic matter by extinguishing while staying for a longer time than the hydraulic retention time of the actual digester, and further increase the amount of biogas generated as energy.

1: digester 2: calibration tank
3: perforated plate 4: gas storage space
5: liquid piping 6: impact pump
7: inlet port 8: outlet port
9: electric valve 10: biogas outlet
11: upflow flow 12: downflow flow
13: hole 14: support
15: cover

Claims (9)

Digestion tank through which the organic matter is introduced through the inlet;
A calibration tank having a space in which liquid can be filled;
A liquid pipe connected to the bottom of the digester from the bottom of the calibration tank; And
An impact pump installed in the liquid pipe to introduce liquid from the correction tank into the digester; Including;
Inducing the upstream flow of the liquid in the digester in accordance with the liquid inflow into the digester through the impact pump and induces the flow of liquid in the digester downflow according to the water level difference between the digester and the calibration tank to mix the organic matter in the digester. Anaerobic digestion system.
The method of claim 1,
Anaerobic digestion apparatus, characterized in that the digester is provided with at least one porous plate having a plurality of holes.
The method of claim 2,
Anaerobic digestion apparatus, characterized in that the cover is provided on the hole of the porous plate supported by at least two or more supports.
The method of claim 3,
The cover is anaerobic digestion apparatus, characterized in that formed in the shape of a dome protruding upwards.
The method of claim 1,
The calibration tank is attached to the upper portion of the digester or anaerobic digestion apparatus, characterized in that installed separately from the digester at the same height as the upper position of the digester.
(a) supplying an organic material to the digester;
(b) introducing a liquid in the correction tank through an impact pump through a lower portion of the digester to induce an upward flow of liquid in the digester; And
(c) stopping the operation of the impact pump and inducing a downward flow of liquid in the digester according to the level difference between the digester and the calibration tank; Anaerobic digestion method comprising a.
The method of claim 6,
Installing at least one porous plate having a plurality of holes in the digester to induce impact mixing of the liquid moving in the digester.
The method of claim 7, wherein
Anaerobic digestion method characterized in that to install a cover supported by at least two supports on the hole of the porous plate to induce impact mixing of the liquid moving in the digester.
The method of claim 6,
The impact pump is operated to induce an upstream flow of the liquid in the digester, the anaerobic digestion method characterized in that for opening the flow path so that the liquid in the digester flows into the correction tank during the downflow of the liquid in the digester.

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