KR101272243B1 - Temperature selectable apparatus for anaerobic treatment of organic waste - Google Patents

Abstract

PURPOSE: A selectively operational anaerobic digestion system for disposing organic waste is provided to treat and control scum generated from an anaerobic digesting operation. CONSTITUTION: An anaerobic digestion system for disposing organic waste includes a raw water storage tank(10), an acid fermenting tank(20), a scum pulverizing tank(30), a methane fermenting tank(40), a cyclone separator(50), and a dual pipe type heat exchanger(60). The dual pipe type heat exchanger receives steam and heats sludge from the acid fermenting tank and the methane fermenting tank. The heated sludge is returned to the acid fermenting bath and the methane fermenting tank. The acid fermenting tank and the methane fermenting tank select either middle temperature or high temperature of the sludge and selectively operate middle temperature digestion or high temperature digestion by indirectly heating the sludge using steam from the dual pipe type heat exchanger as a heating medium. [Reference numerals] (70) TO: Gas pre-treatment facility; (AA,BB) Circulating water; (CC) TO: Boiler

Description

Temporary Selectable Apparatus for anaerobic treatment of organic waste

The present invention relates to a selective operated anaerobic digestion system for treating organic waste, comprising: a raw water storage tank 10 into which organic waste is introduced and stored; and a first transfer pump 13 from the storage raw water storage tank 10. An acid fermentation tank 20 in which an acid fermentation process is received by receiving the organic waste; and a scum discharged through a scum discharge passage 29 installed directly on the water surface of the acid fermentation tank 20. After crushing using the stirring crusher 31, the scum crushing tank 30 to be transferred back to the acid fermentation tank 20 through the third transfer pump 32; and the second transfer from the acid fermentation tank 20 A methane fermentation tank 40 in which a methane fermentation process is performed by receiving the organic wastes transferred through the pump 27; and each of the acid fermentation tanks 20 and scum crushing tanks 30 and the methane fermentation tanks 40 above. The first gas collecting unit 26 and the second gas provided respectively The biogas collected from the collecting part 33 and the third gas collecting part 44 is supplied to separate the moisture and fine dust contained in the biogas, and the cone shape is narrowed downwardly downward. A separator inlet body 51 including the gas inlet 52 formed therein and connected in a tangential direction to an upper circumferential side of the separator body 51, in which the biogas including moisture and fine dust is introduced, and the separator The gas discharge part 53 through which the biogas from which water and fine dust are separated from the center of the main body 51 is introduced and discharged, and the water and fine dust formed at the lowermost end of the separator main body 51 and separated from the biogas. Cyclone separator 50 is configured to include a discharge port for discharging the; and, steam is supplied, acid fermentation tank circulation inlet 61 from the lower portion of the acid fermentation tank 20 Sludge introduced through the methane fermentation tank circulation inflow path 63 from the lower portion of the methane fermentation tank 40 is sent to the acid fermentation tank 20 again by heating the sludge introduced through the acid fermentation tank circulation outlet. A double tube heat exchanger (60) that warms and returns to the methane fermentation tank (40) through a methane fermentation tank circulation outlet (64); Characterized in that comprises a,

According to the operating temperature conditions of the acid fermentation tank 20 or the methane fermentation tank 40, the double tube heat exchanger 60 selectively operates any of medium temperature or high temperature of the introduced sludge. A selective acting anaerobic digestion system for waste disposal.

Organic waste refers to all organisms generated by human activities, and in traditional societies, it played an important role in returning the energy used by humans to the natural cycle of ecosystems, but exceeded midnight capacity in modern integrated industrial society. The enormous amount of organic waste resources generated by this cause total environmental pollution such as water quality, soil and air.

Organic waste disposal methods include ocean dumping, incineration, landfilling and land spraying. However, since 2012, the dumping of ocean dumping has been banned under the London Convention and 96 Protocols, and since 2013, Korea has become a second mandatory country under the Kyoto Protocol, and incineration is subject to institutional restrictions. The importance of fairness can be highlighted.

The anaerobic digestion process, which has been widely applied to the treatment of organic wastes, has the advantage of recovering methane gas as well as volume reduction of organic wastes. Reusing methane produced as the end product of anaerobic digestion process can participate not only in economic benefit but also in clean development system through CO2 emission trading system, and also reduce sludge generation in the whole wastewater treatment process. Is becoming more and more important.

The importance of anaerobic digestion process has been increasing and many studies have been conducted. Currently, the anaerobic digestion process has advantages such as optimization of digestion rate, pH control, and stability against impact load by separating hydrolysis and acid fermentation and methane fermentation. Digestion is drawing attention.

However, while anaerobic digestion has advantages such as energy saving, low microbial production factor, low nutrient requirement and high volume loading, many factors can be used to improve stable operation and processing efficiency. And there is a problem that there is a difficulty in device configuration.

First of all, in anaerobic digestion, temperature maintenance in digester is one of the important driving factors affecting digestion efficiency, stability and microbial activity.

Anaerobic process can be divided into medium temperature digestion (35 ℃) and high temperature digestion (55 ℃) depending on the digester heating conditions. Mid-temperature digestion (35 ℃) has the advantage of easy maintenance in the process of converting to methane by stabilizing the sludge with sufficient residence time in the digester. However, while a long residence time of more than 20 days is required, organic matter weight loss is only about 50% on average, and it is not efficient, and low killing rate of pathogens causes various public health problems at the time of final disposal.

High temperature (55 ℃) anaerobic digestion has the advantage that organic matter reduction rate and pathogen killing rate are relatively high compared to the medium temperature anaerobic digestion process, but it is necessary to continuously warm up to 55 ℃ or more, and additional cost is consumed It has the disadvantage of being sensitive to operating factors such as sludge properties, temperature, organic load rate, etc.

In order to overcome the advantages and disadvantages of each of the medium-temperature digestion and high-temperature digestion in combination with each other, conventionally, a temperature-processing process in which a high-temperature anaerobic digestion tank is internally connected to a medium-temperature anaerobic digestion tank. As in "anaerobic digestion of organic wastewater and waste by", a technique for proceeding a medium temperature digestion and a high temperature digestion is proposed.

However, such a prior art has a problem that both means for warming to maintain a temperature suitable for medium temperature digestion and a means for warming to maintain high temperature digestion are needed to simultaneously perform a medium temperature digestion and a high temperature digestion process. there was.

In relation to such a heating means or a heating method, the heating method for maintaining the temperature in the anaerobic digestion tank at a medium temperature and a high temperature is a direct heating method using steam and an indirect heating method (heat exchanger) in which the sludge digester is heated from an external heat source. Divided.

The direct heating method using dual steam has low initial facility cost and can operate by controlling only the amount of steam when it is applied at medium temperature and high temperature, but it has the disadvantage that it can't uniformly warm the temperature in the digester due to local overheating due to direct injection. have.

Indirect heating method using heat exchanger is mainly used heating method using hot water. Compared to direct injection method, it is relatively easy to operate and maintains uniform temperature in the digester. There is a problem in that an additional cost that needs to be heated to about ℃ ℃ hot water.

Therefore, in order to increase the extinguishing efficiency in anaerobic digestion process, a more economical and efficient heat exchange system is needed for operation by selecting middle temperature and high temperature according to the inflow wastewater properties.

On the other hand, another important factor affecting the treatment efficiency of the anaerobic digester is the generation of digester scum that can occur during actual operation.

The generation of digester scum decreases the efficiency of biogas recovery due to penetration of gas holders, thereby increasing the cost required for biogas utilization such as electricity production.

For this purpose, in the present sewage treatment plant, there is a scum discharge part, but it is not possible to detect a scum at an early stage, so the discharge effect is insignificant, and the gas leak contained in the scum causes stability problems. have.

Another problem arising from the operation of anaerobic digesters is the problem of the efficient separation of moisture and fine dust, which are impurities other than the gases contained in biogas.

In general, anaerobic digestion has to be maintained at a medium temperature and a high temperature in order to generate biogas, so that the temperature is maintained at a constant temperature, so that the biogas flowing through the pipeline through the digester is condensed from the moment it comes into contact with the outside air.

The condensate generated during the condensation process causes the condensate itself to obstruct the flow of gas in the pipe or blockage of the gas pipe due to freezing. If the gas pipe is blocked or damaged, the biogas has a problem in that the inflow of the gas storage tank is not smooth and the yield of the biogas is reduced.

In addition, when the fine dust contained in the biogas is moved to the next gas pretreatment in an untreated state, there is a problem that causes a blockage of the media used for the purpose of biogas purification, resulting in a load.

In order to solve this problem, the sewage treatment plant currently operating anaerobic digestion process is operating a device called “water trap” to remove water and fine dust in biogas, but it has insufficient water removal rate and fine dust. In this case, there is still a problem of flowing to the rear gas pretreatment without being removed.

Patent Document 1: Registered Patent No. 10-0588165

The present invention solves the problems of the existing invention described above, in order to increase the digester efficiency, equipped with an economical and efficient heat exchange system for selectively applying a medium or high temperature anaerobic digestion process according to the inflow wastewater properties in the digester, anaerobic digestion operation Scum can be processed and controlled at an early stage, and efficient separation system of water and fine dust, which are impurities contained in biogas, for efficient extraction and stable operation of biogas, a by-product generated during anaerobic digestion. To provide an anaerobic digestion system having a.

In order to achieve the above object, the present invention, the raw water storage tank 10 in which organic waste is introduced and stored; and the organic waste is supplied from the storage raw water storage tank 10 through the first transfer pump 13 Acid fermentation tank 20 in which the fermentation process proceeds; and the scum discharged through the scum discharge passage 29 installed directly on the water surface of the acid fermentation tank 20 using a second scum agitator crusher 31. Scum crushing tank 30 which is transferred to the acid fermentation tank 20 again through a third conveying pump 32 after crushing by crushing; and is transferred from the acid fermentation tank 20 through the second conveying pump 27. A methane fermentation tank 40 in which a methane fermentation process is carried out by receiving the organic wastes; and a first gas collecting unit installed on each of the acid fermentation tank 20 and the scum crushing tank 30 and the methane fermentation tank 40, respectively. (26), trapping from the second gas collecting unit (33) and the third gas collecting unit (44) Separating the moisture and fine dust contained in the biogas by receiving the collected biogas, the separator body 51 including a cone (cone) that is narrowed downward to the lower side, and containing the moisture and fine dust The biogas is introduced and the gas inlet 52 formed in a tangential direction connected to the upper circumferential side of the separator body 51 and the biogas in which water and fine dust are separated from the center of the separator body 51. Cyclone separator 50 including a gas discharge part 53 which is introduced into and discharged, and a discharge port 54 formed at the lowermost end of the separator body 51 to discharge water and fine dust separated from the biogas. And, by receiving steam, the acid by heating the sludge flowing through the acid fermentation tank circulation inlet 61 from the lower portion of the acid fermentation tank 20 It is sent back to the acid fermentation tank 20 through the hyojo circulation outflow passage 62, and the sludge introduced through the methane fermentation vessel circulation inflow passage 63 from the lower portion of the methane fermentation vessel 40 is heated to methane fermentation vessel circulation outlet ( A double tube heat exchanger 60 which returns back to the methane fermenter 40 through 64; Characterized in that comprises a,

Depending on the operating temperature conditions of the acid fermentation tank 20 or the methane fermentation tank 40 is characterized in that it can selectively operate either medium or high temperature digestion through the double tube heat exchanger (60).

In addition, a first stirrer 11 installed in the raw water storage tank 10; a water gauge 12 installed in the raw water storage tank 10; and a second stirrer 21 installed in the acid fermentation tank 20. And a first scum stirrer 22 installed on the surface of the organic waste in the acid fermentation tank 20; and an acid fermentation tank water level meter installed in the acid fermentation tank 20 to measure the level of the organic waste. 23); and, an acid fermentation tank pressure gauge 24 installed at the upper portion of the acid fermentation tank 20 to measure the pressure inside the acid fermentation tank 20; and, installed at the upper portion of the acid fermentation tank 20, An acid fermentation tank breather valve 25 for discharging the gas inside to the outside when the pressure inside the acid fermentation tank 20 becomes higher than a predetermined pressure; and installed between the acid fermentation tank 20 and the scum discharge passage 29. When the water level measured by the acid fermentation tank water level 23 is a predetermined level or more A scum valve 28 which is opened and closed to discharge the right scum to the scum discharge path 29; and a third stirrer 41 installed in the methane fermentation tank 40; and the organic matter in the methane fermentation tank 40. A third scum stirrer 42 installed on the surface of the waste; and installed at an upper portion of the methane fermentation tank 40, when the pressure inside the methane fermentation tank 40 becomes equal to or higher than a predetermined pressure, the internal gas is moved outward. A methane fermenter breather valve 43 for discharging; Characterized in that further comprises.

In addition, the double tube heat exchanger 60 is composed of a double tube consisting of a steam inner pipe 65a and a steam outer pipe 65b, and the sludge to be heated from one side of the steam inner pipe 65a is The steam double pipe heat exchanger 65 which is introduced and supplies steam from the other side of the steam outer pipe 65b to the space 65c between the steam inner pipe 65a and the steam outer pipe 65b to indirectly warm the sludge. It is characterized in that it further comprises a).

According to the present invention, it is possible to selectively apply the medium or high temperature anaerobic digestion process according to the inflow wastewater properties in the digester, and also has an advantage that the indirect heating can be appropriately and efficiently using steam by the double tube heat exchanger. .

In addition, the scum generated during the anaerobic digestion operation can be treated and controlled at an early stage. The cyclone separator is used to collect moisture, residual scum, and fine dust, which are impurities contained in biogas, a by-product generated during the anaerobic digestion process. Since it is possible to efficiently separate, the biogas can be efficiently extracted and stable operation, as well as there is an advantage that it is possible to efficiently remove it even in abnormal situations in which scum is introduced.

Figure 1: Schematic diagram of the overall configuration of the anaerobic digestion system according to an embodiment of the present invention.
Figure 2 is a schematic diagram showing the configuration of a double tube heat exchanger of the anaerobic digestion system according to an embodiment of the present invention.
3: A schematic diagram showing the configuration of a cyclone separator of the anaerobic digestion system according to an embodiment of the present invention.
4 is a graph showing a scum sensing condition through changing the pressure and water level in an acid fermentation tank of an anaerobic digestion system according to an embodiment of the present invention.
5 is a graph showing the water removal rate of the cyclone separator of the anaerobic digestion system according to an embodiment of the present invention and the conventional partition type separator.
6 is a graph illustrating a comparison of fine dust removal rates between a cyclone separator and a conventional partition type separator (water trap) of an anaerobic digestion system according to an embodiment of the present invention.

Hereinafter will be described in detail the selective operation anaerobic digestion system for organic waste treatment according to an embodiment of the present invention. First, it should be noted that, in the drawings, the same components or parts are denoted by the same reference numerals whenever possible. In describing the present invention, detailed descriptions of related well-known functions or configurations are omitted in order not to obscure the subject matter of the present invention.

1, the raw water storage tank 10, acid fermentation tank 20, scum crushing tank 30, methane fermentation tank 40, cyclone separator 50, double tube heat exchanger as shown in FIG. Characterized in that it comprises a (60).

First, the raw water storage tank 10 will be described. The raw water storage tank 10 is a facility having a role of a storage tank capable of storing a high concentration of organic waste and a role of a flow control tank. The raw water storage tank 10 absorbs and equalizes changes in the flow rate and water quality of the incoming wastewater, thereby lowering the inflow load of the post-stage process and treating efficiency. It is a facility installed for the purpose of improving the quality.

In this case, the raw water storage tank 10, as shown in Figure 1, the first stirrer 11 is further installed to prevent the generation of suspended matter, sludge sediment and the high concentration of organic waste can be efficiently stirred and mixed It is desirable to.

In addition, it is preferable that the level gauge 12 is further installed in the raw water storage tank 10 so that the level of the highly concentrated organic waste can be detected.

Next, the acid fermentation tank 20 will be described. The acid fermentation tank 20 is an anaerobic digestion tank in which the organic waste is acid fermented by culturing in an acid fermentation microorganism in a high concentration of organic waste. In the acid fermentation tank 20, as shown in FIG. 1, an acid fermentation process is performed by receiving the organic waste from the storage raw water storage tank 10 through a first transfer pump 13.

On the other hand, as shown in Figure 1 for efficient stirring light mixing of the organic waste during the acid fermentation process, in order to prevent the generation of suspended matter, sludge precipitate in the reaction tank, to promote the reaction of microorganisms, in the acid fermentation tank 20 It is preferable to further include a second stirrer 21 to be installed.

On the other hand, the scum generated during the fermentation process is a major factor that lowers the operating efficiency, so it is necessary to remove it quickly and efficiently. To this end, as shown in FIG. 1, the first scum stirrer 22 is further installed on the surface of the organic waste in the acid fermentation tank 20, so that a substance floating on the surface of the water above a certain level is regarded as a scum. By the first scum stirrer 22 to be primarily crushed.

In addition, the acid fermentation tank 20 is installed in the acid fermentation tank 20, the acid fermentation tank level meter 23 for measuring the level of the organic waste, and the upper portion of the acid fermentation tank 20, as shown in FIG. It is preferable to further include an acid fermentation tank pressure gauge 24 installed to measure the pressure inside the acid fermentation tank 20.

On the other hand, the anaerobic digestion process is a production process of a highly combustible biogas, as shown in Figure 1 to provide a safety valve for maintaining the internal pressure in a certain range by the operation stabilization method, the acid fermentation tank 20 It is preferable to further include an acid fermentation tank breather valve 25 installed at an upper portion of the acid fermentation tank 20 to discharge the gas inside when the pressure inside the acid fermentation tank 20 becomes higher than a predetermined pressure.

Next, the scum crushing tank 30 will be described. As shown in FIG. 1, the scum crushing tank 30 has a scum discharged through the scum discharge passage 29 installed directly on the water surface of the acid fermentation tank 20. After crushing by using, and has a function to transfer back to the acid fermentation tank 20 through the third transfer pump (32).

That is, the scum discharged from the acid fermentation tank 20 stays in the scum crushing tank 30 for a predetermined time and is completely crushed through the second scum crushing stirrer 31, and the crushed scum is an organic substance. Since it contains the recycle to the acid fermentation tank 20 by the third transfer pump (32).

In this case, the scum that is not removed through the first scum agitator 22 has a characteristic of bringing the water level in the acid fermentation tank 20 and increasing the pressure. Thus, the acid fermentation tank 20 and the scum discharge path 29 is installed between the opening and closing to discharge the scum to the scum discharge path 29 when the water level measured by the acid fermentation tank level gauge 23 or more. It is preferable to further comprise a scum valve 28 to be configured. In this case, when the relative value of the pressure and the water level in the normal operation is assumed to be 1, the level rise and the pressure increase due to the occurrence of scum (scum) through the acid fermentation tank level gauge 23 and the acid fermentation tank pressure gauge 24 When it is detected, as shown in FIG. 4, when the valve is increased by about 1.2 times or more, the automatic valve 28 operates to form the upper gas-liquid boundary layer of the acid fermentation tank 20. A scum is formed through the scum discharge unit 29. scum) to be discharged to the crushing tank (30).

Next, the methane fermentation tank 40 is demonstrated. As illustrated in FIG. 1, the methane fermentation tank 40 has a function of receiving an organic waste transferred from the acid fermentation tank 20 through a second transfer pump 27 to proceed with a methane fermentation process.

The methane fermentation tank 40 is an anaerobic digestion tank in which methane is fermented by culturing methane fermentation microorganisms in the sludge discharged from the acid fermentation tank 20. The methane fermentation tank 40 is characterized in that the decomposition by the microorganism is optimized at a pH of about 7 ~ 8.5, preferably to maintain the pH 7.5 ~ 8.5 in consideration of the characteristics of the methane fermentation process weak to environmental changes desirable. In the methane fermentation tank 40, carbon dioxide and methane gas are generated while methane microorganisms decompose acetic acid generated while passing through the acid fermentation tank 20.

In this case, similarly to the case of the acid fermentation tank 20, the methane fermentation tank 40, as shown in Figure 1, the third stirrer 41 is installed in the methane fermentation tank 40, and the methane fermentation tank 40 The third scum stirrer 42 installed on the water surface of the organic waste in the c) and the upper portion of the methane fermentation tank 40, and the internal gas when the pressure inside the methane fermentation tank 40 becomes equal to or greater than a predetermined pressure. It is preferable that the methane fermenter breather valve 43 for discharging to the outside further comprises.

Next, the cyclone separator 50 is demonstrated. As shown in FIG. 1, the cyclone separator 50 includes a first gas collecting unit 26 and a second gas fermenter 20 installed above each of the acid fermentation tank 20, the scum crushing tank 30, and the methane fermentation tank 40, respectively. The biogas collected from the gas collecting unit 33 and the third gas collecting unit 44 has a function of separating water, residual scum, and fine dust contained in the biogas. As shown in FIG. 3, a separator main body 51 including a cone shape narrowing downward and narrowing down, and the biogas containing water and fine dust are introduced into the separator main body 51. The gas inlet 52 which is connected in a tangential direction to the upper circumferential side of the c) and the biogas in which water and fine dust are separated from the center of the separator body 51 are drawn in and discharged. To the gas discharge portion 53, is formed at the bottom of the separator body 51 is configured to include an outlet 54 for discharging the water and the fine dust separated from the biogas is preferred.

That is, the mixture of biogas and impurities which are instantaneously introduced into the separator main body 51 is rotated on the inner wall surface of the separator main body 51 to generate the centrifugal force. Accordingly, the water having a mass, residual scum, and fine dust are separated from the biogas whose mass is almost neglected, flows through the inner wall surface of the separator body 51, and descends by its own weight. Is discharged through.

Biogas from which moisture, residual scum, and fine dust has been removed by the above-described action is piggybacked on an exhaust air stream that rises along the center of the separator body 51, and is separated and transported through the gas discharge unit 53 in a post-stage process.

In this case, as compared with the bulkhead type remover generally used in the water removal efficiency contained in the biogas, the water removal rate of the partition type remover is about 25-40%, as shown in FIG. Cyclone separator 50 is removed by 45-60%, it was shown that the water removal rate is higher than the conventional bulkhead type remover.

In addition, compared to the bulkhead type remover generally used in the fine dust removal efficiency included in the biogas, as shown in FIG. 6, the fine particle removal rate is about 25-40%, as shown in FIG. 6. The cyclone separator 50 was removed by 40-55%, it was found that the fine dust removal rate is higher than the conventional bulkhead type remover.

Next, the double tube heat exchanger 60 will be described. As shown in FIG. 1, the double tube heat exchanger 60 receives steam and warms sludge introduced through an acid fermentation tank circulation inlet 61 from a lower portion of the acid fermentation tank 20 to circulate acid fermentation tank circulation. It is sent to the acid fermentation tank 20 again through the furnace 62, and the methane fermentation tank circulation outlet 64 is heated by heating the sludge introduced from the lower portion of the methane fermentation tank 40 through the methane fermentation tank circulation inflow passage 63. Through it has a function to return to the methane fermentation tank 40 again. In this case, the double tube heat exchanger 60 is the double tube heat exchanger 60 according to the operating temperature conditions of the acid fermentation tank 20 or the methane fermentation tank 40, the medium temperature or high temperature of the introduced sludge It is desirable to be able to select any one and selectively indirectly warm it.

As a preferred embodiment of the double tube heat exchanger 60 having the above function, as shown in FIG. 2, the double tube heat exchanger 60 includes a steam inner pipe 65a and a steam outer pipe ( It consists of a double pipe consisting of 65b), the sludge to be heated from one side of the steam inner pipe (65a) is introduced, and the steam inner pipe (65a) and the steam outside from the other side of the steam outer pipe (65b) It is preferred to further comprise a steam double tube heat exchanger (65) in which steam is supplied to the space (65c) between the pipes (65b) to indirectly warm the sludge.

As a result of the test operation of the double tube heat exchanger 60, the required heat amount during the medium-temperature fire (35-38 ° C.) operation is assumed to be 10 tons per hour as shown in Table 1 below. It was about 400,000kcal / ton ton at high temperature digestion (55-65 ℃).

division
Medium temperature High temperature fire extinguishing hot water steam hot water steam Required temperature (℃) 35 ~ 38 55-65 Inflow (ton / hr) 10 10 Required calories (㎉ / ton) 200,000 400,000 Heat exchange area (㎡) 1.5 0.8 3 1.5 Residence time (sec.) 5 2.5 10 5

When hot water is used for the heat medium as in the conventional method, the introduced sludge at 15 ° C absorbs heat through the warm water and is discharged at 40 ° C. In this case, the heat exchanger area was irradiated to about 1.5 m 2 at medium temperature heating and about 3 m 2 at high temperature heating, as shown in Table 1 above.

On the other hand, when the heat medium is used as steam, that is, when the steam double tube heat exchanger (65) is used, as shown in FIG. 2, the temperature of steam introduced from the other side of the steam double tube heat exchanger (65) is about 150 to With high temperature steam at 180 ° C., heat is transferred through the steam inner pipe (65a) while passing through the steam double tube heat exchanger (65) and discharged into condensed water at about 35 to 50 ° C. During this process, 15 ° C sludge introduced from one side of the steam double tube heat exchanger 65 absorbs heat while passing through the hot water double tube heat exchanger 65 and is heated to 45 to 75 ° C.

As can be seen from the comparison, when the hot water is used, the heat exchanger area is about 1.5 m 2 at medium temperature heating and about 3.0 m 2 at high temperature digestion, as shown in Table 1 above. As shown in Table 1, it was found that the heat exchanger area of about half of the case of using hot water was about 0.8 m 2 at medium temperature heating and about 1.5 m 2 at high temperature digestion. The heat exchanger area, which is much smaller than the conventional method using hot water, can reduce the size of the heat exchanger itself to 1/2 or less, thereby reducing the installation space, and also has the effect that the manufacturing and installation costs can be water. have.

In addition, even in the case of the residence time required for warming, when using hot water as in the basic invention, as shown in Table 1, it takes about 5 seconds / 10 seconds for medium to high / high temperature heating, respectively, In the case of using the steam heating according to the present invention, it is shown that it takes about 2.5 seconds / 5 seconds each for medium temperature heating / high temperature heating, and much faster heating is possible. The characteristics that can shorten the heating time in conjunction with the effect of reducing the heat exchanger area as described above, largely the same or more efficient heat exchange effect with only about 1/4 the size of the existing hot water heat exchanger I can bring it.

As described above, according to the present invention, by using the double tube heat exchanger 60 having the steam double tube heat exchanger 65, the medium or high temperature heating is resilient depending on the heat medium by the steam which can be supplied during the medium and high temperature digestion operation. It is possible to perform selectively, to cope with various operating environments economically and efficiently.

Best Mode for Carrying Out the Invention Best modes have been disclosed in the drawings and specification. Although specific terms have been employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

10: raw water storage tank 11: first stirrer
12: level gauge 13: first transfer pump
20: acid fermentation tank 21: second stirrer
22: first scum agitator 23: acid fermenter water level meter
24: acid fermenter pressure gauge 25: acid fermenter breather valve
26: first gas collecting portion 27: second transfer pump
28: scum valve 29: scum exhaust path
30: scum crushing tank 31: second scum agitator
32: third transfer pump 33: second gas collecting portion
40: methane fermenter 41: third stirrer
42: third scum agitator 43: methane fermenter breather valve
44: third gas collector 45: methane fermenter level gauge
50: cyclone separator 51: separator body
52: gas inlet 53: gas outlet
54: outlet
60: double tube heat exchanger
61: acid fermenter circulation inlet 62: acid fermenter circulation inlet
63: methane fermenter circulation inlet 64: methane fermenter circulation inlet
65: steam double tube heat exchanger
65a: steam inner pipe 65b: steam outer pipe
70: gas pretreatment facility

Claims (3)

Raw water storage tank 10 in which organic waste is introduced and stored;
An acid fermentation tank 20 in which an acid fermentation process is received by receiving the organic waste from the storage raw water storage tank 10 through a first transfer pump 13;
After the scum discharged through the scum discharge passage 29 installed just above the surface of the acid fermentation tank 20 is crushed using the second scum agitator crusher 31, the third transfer pump 32 is Scum crushing tank 30 to be transferred back to the acid fermentation tank 20 through;
A methane fermentation tank 40 in which a methane fermentation process is received by receiving the organic waste transferred from the acid fermentation tank 20 through a second transfer pump 27;
The first gas collecting unit 26, the second gas collecting unit 33, and the third gas collecting unit 44 respectively installed above the acid fermentation tank 20, the scum crushing tank 30, and the methane fermentation tank 40, respectively. Separating the moisture, residual scum and fine dust contained in the biogas received from the collected biogas, and the separator body 51 including a cone (cone) that is narrowed downwards downward, And a gas inlet 52 formed with the biogas including fine dust and connected in a tangential direction to an upper circumferential side of the separator body 51, and water remaining from the center of the separator body 51. A gas discharge part 53 through which the biogas separated from the scum and the fine dust is introduced and discharged, and formed at the bottom of the separator body 51 and discharged the water and the fine dust separated from the biogas A cyclone separator 50 comprising an outlet 54;
When steam is supplied, the sludge introduced through the acid fermentation tank circulation inlet 61 from the lower part of the acid fermentation tank 20 is heated and sent back to the acid fermentation tank 20 through the acid fermentation tank circulation outlet 62. The double tube heat exchanger which warms the sludge introduced from the lower portion of the methane fermenter 40 through the methane fermenter circulation inlet 63 and returns it back to the methane fermenter 40 through the methane fermenter circulation outlet 64. 60); Characterized in that comprises a,
Depending on the operating temperature conditions of the acid fermentation tank 20 or the methane fermentation tank 40, the temperature of the sludge introduced by the steam as a heat medium through the double tube heat exchanger (60) by selecting either medium or high temperature Optionally actuated anaerobic digestion system for the treatment of organic waste, characterized in that it can be selectively indirectly heated to selectively operate medium or high temperature digestion.
The method according to claim 1,
A first stirrer (11) installed in the raw water reservoir (10);
A water level gauge 12 installed in the raw water reservoir 10;
A second stirrer 21 installed in the acid fermentation tank 20;
A first scum stirrer 22 installed on the water surface of the organic waste in the acid fermentation tank 20;
An acid fermentation tank level meter 23 installed in the acid fermentation tank 20 to measure the level of the organic waste;
An acid fermentation tank pressure gauge 24 installed at an upper portion of the acid fermentation tank 20 to measure a pressure inside the acid fermentation tank 20;
An acid fermentation tank breather valve (25) installed at an upper portion of the acid fermentation tank (20) and discharging the gas inside to the outside when the pressure in the acid fermentation tank (20) becomes higher than a predetermined pressure;
The scum which is installed between the acid fermentation tank 20 and the scum discharge path 29 and is opened and closed to discharge the scum to the scum discharge path 29 when the water level measured by the acid fermentation tank level gauge 23 is greater than or equal to a predetermined level. Valve 28;
A third stirrer 41 installed in the methane fermentation tank 40;
A third scum stirrer (42) installed on the water surface of the organic waste in the methane fermentation tank (40);
A methane fermentation tank breather valve 43 installed at an upper portion of the methane fermentation tank 40 and discharging gas inside when the pressure inside the methane fermentation tank 40 becomes greater than or equal to a predetermined pressure; Selective operating anaerobic digestion system for organic waste treatment, characterized in that further comprises.
The method according to claim 1 or 2,
The double tube heat exchanger 60,
It consists of a double pipe consisting of a steam inner pipe (65a) and the steam outer pipe (65b), the sludge to be heated from one side of the steam inner pipe (65a) is introduced, the other side of the steam outer pipe (65b) A steam double pipe heat exchanger (65) from which steam is supplied to the space (65c) between the steam inner pipe (65a) and the steam outer pipe (65b) to indirectly warm the sludge; Selective operating anaerobic digestion system for organic waste treatment, characterized in that further comprises.

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