WO2015160075A1

WO2015160075A1 - Anaerobic digesting equipment having internal circulating apparatus for removing scum and increasing produced amount of digestion gas

Info

Publication number: WO2015160075A1
Application number: PCT/KR2015/000476
Authority: WO
Inventors: 이종인; 이창열
Original assignee: 에스케이케미칼 주식회사
Priority date: 2014-04-17
Filing date: 2015-01-16
Publication date: 2015-10-22
Also published as: KR20150120065A

Abstract

The present invention relates to anaerobic digesting equipment having an internal circulating apparatus for removing scum and increasing the produced amount of digestion gas and, more particularly, to anaerobic digesting equipment having an internal circulating apparatus for removing scum and increasing the produced amount of digestion gas, which efficiently removes scum produced at a gas-liquid boundary layer at the upper portion of an anaerobic digesting facility at an early stage, and activates the stirring of organic waste inside a digestion tank so as to increase the produced amount of digestion gas. In particular, the present invention seeks to provide anaerobic digesting equipment having an internal circulating apparatus for removing scum and increasing the produced amount of digestion gas, which, in a process of producing digestion gas by introducing organic waste from the outside into an anaerobic digesting device and digesting same, uses a pump to transfer organic waste at the lower portion of the anaerobic digesting device to the upper portion of the anaerobic digesting device to reintroduce and circulate same, and suctions scum produced at the gas-liquid boundary layer inside the anaerobic digesting device into a liquid portion of the anaerobic digesting device so as to remove the produced scum, so that digestion gas produced in the liquid portion due to the removal of scum can be easily transferred to a gas portion and discharged.

Description

Anaerobic Digestion Facility with Internal Circulation System for Scum Removal and Increased Exhaust Gas Production

The present invention relates to an anaerobic digestion apparatus having an internal circulation device for removing scum and increasing digestion gas production, and more particularly, to efficiently remove scum generated in the gas-liquid boundary layer above the anaerobic digestion system, and The present invention relates to an anaerobic digestion system having an internal circulation device for scum removal and an increase in the amount of extinguishing gas that can increase the amount of extinguishing gas generated by activating agitation of organic waste.

In general, organic waste such as livestock manure and food waste, including sewage sludge generated during sewage treatment, is known to be able to generate digestive gas through an anaerobic digestion process. Methane, and after separation, methane can be reused as an energy source, such as a boiler.

In order to stabilize the anaerobic digestion process, a single phase, abnormal or mesophilic digestion process is performed, and such a process has a long residence time of 20 to 30 days or more, while the amount of digested gas stays at 10 m3 / ton. have.

In addition, a large amount of floating scum (Scum) is generated in the gas-liquid boundary layer in the anaerobic digestion facility, it is known that the scum has a high viscosity to prevent the release of gas.

More specifically, the scum is known to occur when an imbalance of digestion occurs due to an overload of organic matter in the digester, a sudden drop in temperature, inadequate agitation in a digester, a poison or heavy metal input, and the like. It reduces the capacity and at the same time causes the problem of suppressing the upper movement for the discharge of digestive gas, and when excessive scum occurs, enters the passage of the digestive gas to obstruct the movement of the digestive gas or closes the passage of the digestive gas Because of the problem of preventing the movement of gas, proper removal of scum is essential.

As a prior art for proper removal of scum, Korean Patent Laid-Open Publication No. 2010-0112430 (2010.10.19) is provided on the stirring shaft inside the anaerobic digestion tank and is formed on the gas liquid boundary layer of the anaerobic digestion tank while rotating along the stirring shaft ( Disclosed is a scum removal apparatus including a scum grinder for grinding a scum layer, and a discharge part in which scum comminuted by the scum grinder is introduced and discharged to the outside of the anaerobic digestion tank.

However, it is not possible to guarantee that the crushed scum is smoothly discharged through the scum discharge port, and thus the scum discharge effect is insignificant, and the extinguishing gas recovery rate through the anaerobic digestion process is caused by the digestion gas contained in the scum leaking to the outside. There is a falling problem.

The present invention has been made in order to solve the above-mentioned problems, the organic waste from the bottom of the anaerobic digestion apparatus in the process of making the digestion gas by introducing organic waste from the outside into the anaerobic digestion apparatus of the anaerobic digestion apparatus using a pump By transferring to the upper part and re-injecting and circulating, the scum generated in the gas-liquid boundary layer inside the anaerobic digestion apparatus can be pulled into the liquid portion of the anaerobic digestion apparatus to remove the scum generated and the extinguishing generated in the liquid portion according to the scum removal. An object of the present invention is to provide an anaerobic digestion system having an internal circulation device for removing scum and increasing the amount of extinguishing gas that can be smoothly transported and discharged to the gas unit.

In addition, another object of the present invention is to agitate the organic waste circulating in the anaerobic digestion apparatus with an agitation means to increase the amount of digested gas produced.

In order to achieve the above object, the present invention includes: an anaerobic digestion tank formed with an external inlet port at one side to fill a predetermined amount of organic waste, and an extinguishing gas outlet at which the extinguishing gas of the organic waste is discharged at an upper end thereof; Internal circulation means for internally circulating the organic waste in the anaerobic digester up and down while repeating the recycling operation of discharging the organic waste filled in the anaerobic digester to the bottom and resupplying the upper portion; Heating means for heating the organic waste flowing from the lower portion of the anaerobic digestion tank to the upper portion along the inner circulation means at an appropriate temperature; It provides an anaerobic digestion facility having an internal circulation device for removing scum and increasing the amount of digestion gas generated, characterized in that configured to include.

Preferably, the anaerobic digestion apparatus of the present invention is further characterized by a stirrer rotatably arranged in the anaerobic digestion tank to agitate the organic waste to circulate.

In particular, the internal circulation means: an internal circulation pipe connecting an internal outlet formed in the lower portion of the anaerobic digestion tank and an internal inlet formed in the upper portion; An internal circulation pump configured to pump and supply the organic waste discharged from the internal outlet toward the internal inlet; Characterized in that consisting of.

In addition, the heating means includes: a coolant tank for storing the coolant; A heating tube mounted to an outer diameter or an inner diameter of the inner circulation pipe of the inner circulation means; A supply side circulation line connected between the outlet of the coolant tank and the inlet of the heating pipe; A discharge side circulation line connected between an inlet of the coolant tank and an outlet of the heating pipe; A coolant circulation pump mounted on the supply side circulation line and circulating the coolant in the coolant tank to the heating pipe; A heater mounted in the coolant tank to heat the coolant for temperature control of the coolant; A controller for controlling an operation cycle and a time of the heater to adjust a coolant temperature in the coolant tank; Characterized in that configured to include.

Preferably, the heating tube is characterized by maintaining the surface temperature of 20 ~ 60 ± 10 ℃ by the refrigerant or fruit flowing therein.

Through the above problem solving means, the present invention provides the following effects.

First, in the process of making organic waste from the outside by introducing organic waste into the anaerobic digestion apparatus, by repeating the circulation operation of the organic waste re-introduced by transferring the organic waste of the lower portion of the anaerobic digestion tank to the upper portion of the anaerobic digestion tank by using a pump. Scum generated in the gas-liquid boundary layer inside the digester is drawn into the liquid portion of the anaerobic digester by the re-injected organic waste and can be easily removed.

Second, as scum generated in the gas-liquid boundary layer inside the anaerobic digestion tank is removed, the digestion gas generated in the liquid portion can be smoothly transferred to the gas portion and discharged smoothly through the digestion gas discharge portion formed at the top of the anaerobic digestion tank. Digestion gas production and collection can be increased.

Third, by stirring the organic waste circulating in the anaerobic digestion tank with a stirring means, the contact between the digestive gas generating microorganisms in the anaerobic digestion tank and the organic waste can be increased to further increase the amount of digestive gas generated in the liquid portion.

1 is a block diagram showing an anaerobic digestion facility having an internal circulation device for removing scum and increasing digestion gas production amount according to the present invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The present invention is to provide an internal circulation means to the anaerobic digester in order to quickly and stably remove scum generated in the anaerobic digester (or anaerobic digester), the organic waste of the lower portion of the anaerobic digester to the gas above the anaerobic digester By re-injecting through the secondary (empty space not filled with organic waste), the scum of the gas-liquid boundary layer is drawn into the liquid portion and removed by the re-injected organic waste, thereby increasing the amount of extinguishing gas and simultaneously extinguishing gas. The point is to make the collection smooth.

1 is a block diagram showing an anaerobic digestion system having an internal circulation device for removing scum and increasing the amount of extinguishing gas generated in accordance with the present invention.

In Fig. 1, reference numeral 10 denotes an anaerobic digestion apparatus, that is, an anaerobic digestion tank.

The anaerobic digestion tank 10 is a hollow cylindrical storage tank, which is supported by a base frame (not shown) and installed in a vertical direction. A structure in which an insulation material (not shown) is attached to an outer surface to maintain an internal temperature. It is provided with.

In addition, an outer inlet 12 is formed at one lower end of the anaerobic digestion tank 10 to introduce organic waste from the outside into the interior of the anaerobic digestion tank, and at one upper end, an external inflow of organic waste in the anaerobic digestion tank 10 to the outside. Outlet 13 is formed, the upper end is connected to the extinguishing gas discharge port 14 for discharging the extinguishing gas generated in the anaerobic digestion tank 10 to the outside.

In particular, an inner outlet 16 for circulating organic waste in the anaerobic digestion tank 10 is formed at the lower end of the anaerobic digestion tank 10, that is, the upper end of the anaerobic digestion tank 10, that is, the digestion gas outlet 14 and In the position between the outer outlets 13 is formed an inner inlet 18 for circulating and resupplying organic waste discharged from the inner outlet 16.

At this time, inside the anaerobic digestion tank 10 provided as described above, a stirrer 40 for stirring organic waste is rotatably mounted, for example, a rotary motor is mounted at the top of the anaerobic digestion tank 10 and rotated at the same time. Stirring shaft and vanes connected to the shaft of the motor are arranged up and down in the inner central portion of the anaerobic digestion tank.

According to the present invention, the internal circulation means for discharging the organic waste filled in the anaerobic digestion tank 10 through the internal outlet 16 and at the same time to be re-supplied to the upper portion in the anaerobic digestion tank 10 through the internal inlet ( 20) is connected to the anaerobic digester (10).

The internal circulation means 20 is discharged from the internal circulation pipe 22 and the internal outlet 16 connecting the internal inlet 16 formed in the lower portion of the anaerobic digester 10 and the internal inlet 18 formed in the upper portion It consists of an internal circulation pump 24 for pumping and supplying the organic waste to the internal inlet 18, the internal circulation pump 24 is installed close to the internal outlet (16).

According to the present invention, the internal circulation pipe 10 is connected to a heating means 30 for controlling the temperature for organic waste, the heating means 30 is the anaerobic digestion tank 10 along the internal circulation pipe 22 It is provided to heat the organic waste flowing from the lower part to the upper part to the proper temperature.

As one configuration of the heating means 30, the heating tube 32 is mounted to the outer or inner diameter of the inner circulation pipe 22.

The heating tube 32 is supplied with a coolant from the coolant tank 31 for storing the coolant so that heat exchange is performed for the purpose of maintaining the temperature of the organic waste transported through the inner circulation pipe 22.

At this time, the outlet of the coolant tank 31 and the inlet of the heating tube 32 are connected via a supply side circulation line 33, and the inlet of the coolant tank 31 and the outlet of the heating tube 32 are It is connected via the discharge side circulation line 34.

In addition, the supply side circulation line 33 is equipped with a coolant circulation pump 35 for pumping and circulating the coolant in the coolant tank 31 to the heating pipe (32).

In addition, the coolant tank 31 has a heater 36 for heating the coolant to adjust the temperature of the coolant, and the operation cycle and time of the heater 14 may be used to control the coolant temperature. It is controlled by the controller 37.

Therefore, when the coolant circulation pump 35 operates under the control of the controller 37 and the heater 14 operates, the coolant in the coolant tank 31 is temperature-controlled by the operation of the heater 14. At the same time flows to the heating pipe 32 along the supply side circulation line 33, heat exchange with the organic waste flowing in the internal circulation pipe 22 can be maintained, thereby maintaining the organic waste at an appropriate temperature.

On the other hand, although not shown in the drawings, a supply device (not shown) for supplying organic waste is connected to the outer inlet 12 of the anaerobic digestion tank 10, the organic waste is finished anaerobic digestion to the outer outlet (13) An organic waste treatment device (not shown) for treatment is connected, and the digestion gas outlet 14 is connected to a digestion gas collection and purification device (not shown).

In addition, the anaerobic digestion tank 10, the coolant tank 31, the outer inlet 12 and the outer outlet 13, the inner outlet 16 and the inner inlet 18, the extinguishing gas outlet 14, etc. Measurement sensors and equipment (not shown) and on-off valves (not shown) that can check the state are attached.

Here, the operation flow for the anaerobic digestion plant of the present invention having the configuration as described above is as follows.

First, the organic waste to produce digestive gas through anaerobic digestion is supplied into the anaerobic digestion tank 10 through an external inlet 12.

The anaerobic digestion tank 10 can be operated at a constant temperature (20 ~ 60 ± 10 ° C. based on the total), but operation at a high temperature of 55 ± 5 ° C. is preferable.

In general, anaerobic digestion using organic wastes is performed at medium or high temperatures, in which medium and high temperatures usually mean 35 ° C and 55 ° C.

In addition, since organic wastes injected for anaerobic digestion usually maintain normal temperatures (0 ° C to 15 ° C), heating up to only medium temperature of 35 ° C requires less energy than heating up to high temperature of 55 ° C. Usually implemented.

However, in the present invention, since the organic waste discharged after being pretreated at a high temperature of 160 ° C. in the pretreatment step is used by cooling, it is easier to apply to an anaerobic digestion tank that maintains a high temperature of 55 ° C. rather than a medium temperature of 35 ° C. In addition, the introduction of organic waste at the same temperature as the anaerobic digester also provides the advantage of minimizing the energy required to heat the anaerobic digester.

In addition, the agitator 40 in the anaerobic digestion tank 10 is rotated by the controller's control signal to agitate the organic waste. Preferably, the digestion gas generating microorganisms in the anaerobic digestion tank 10 are contacted with the organic waste. The stirring operation is performed at an appropriate speed to increase, and the organic waste in the anaerobic digestion tank 10 is maintained in a circulated state without being precipitated downward.

In addition, the organic waste supplied into the anaerobic digestion tank 10 is circulated in the anaerobic digestion tank by the stirring operation of the stirrer 40 to generate a digestive gas, and then discharged through the external outlet 13, and the generated digestive gas is The digestion gas discharge port 14 is transferred to the digestion gas collection and purification device (not shown).

At this time, the internal circulation pump 24 is operated by a signal from the controller, the organic waste of the lower side of the anaerobic digestion tank 10 is discharged through the internal outlet 16 and at the same time the internal outlet (22) along the internal circulation pipe 22 After being pumped up to 16), it is re-injected through the upper part (empty space gas part) in the anaerobic digestion tank 10.

Therefore, as the organic waste re-injected into the anaerobic digestion tank 10 falls, the scum generated in the gas-liquid boundary layer in the anaerobic digestion tank 10 (the surface of the liquid portion of the organic waste forming the boundary with the gaseous portion) is brought into the liquid portion. Thus, the scum of the gas-liquid boundary layer can be easily removed, and the circulation of the organic waste in the anaerobic digestion tank 10 is activated by moving the lower organic waste to the top.

Accordingly, in the past, the extinguishing gas generated in the liquid portion of the organic waste is collected and stagnated by the scum layer before removal, which existed in the gas-liquid boundary layer, and thus, the amount of extinguishing gas collected by the scum is reduced. Since the scum generated in the gas-liquid boundary layer inside the anaerobic digestion tank is easily removed, the digestion gas generated in the liquid portion can be smoothly transferred to the gas portion and discharged smoothly through the digestion gas discharge formed at the top of the anaerobic digestion tank. As a result, it is possible to increase the amount of digested gas produced and collected.

On the other hand, in operating the anaerobic digestion tank 10, the stirring through the stirrer 40 is carried out continuously, scum removal and stirring through the internal circulation means is made intermittently, preferably anaerobic digestion tank 10 In consideration of the size of the internal circulation, the performance of the internal circulation pump 24, the amount of scum, etc., the number and time of internal circulation of organic wastes are appropriately controlled, but 1 to 4 times / day and 0.5 to 1 hour / time are preferable. .

In addition, when the internal circulation means 20 is driven, the external inlet 12 and the external outlet 13 of the anaerobic digestion tank 10 are preferably temporarily closed, but the external inflow and outflow of organic waste is made. You can drive even in situations.

The internal circulation pump 24 of the internal circulation means 20 is driven, and before the organic waste is circulated along the internal circulation pipe 22, the internal circulation pipe 22 is the same temperature condition as the temperature in the anaerobic digestion tank 10. Preferably, the internal circulation pipe 22 is heated by the heating means 30 provided as above.

To this end, the controller 37 first turns on the heater 36 in the coolant tank 31 to heat the coolant in the coolant tank 31 to a set temperature.

Subsequently, when the temperature of the coolant and the temperature set by the controller 37 become equal, the coolant in the coolant tank 31 is supplied to the supply side circulation line by operating the coolant circulation pump 35 in the controller 37. 33) to the heating tube (32).

Thus, the heat exchange between the coolant flowing through the heating tube 32 and the inner circulation pipe 22 is made, preferably the surface temperature of the heating tube 32 is maintained by 20 ~ 60 ± 10 ℃ by the cold refrigerant At the same time, the internal circulation pipe 22 is also maintained at 20 to 60 ± 10 ° C by heat exchange, and thus the temperature of the organic waste flowing in the internal circulation pipe 22 can be controlled to be the same as the temperature in the anaerobic digestion tank.

The reason for heating the organic waste circulating from the bottom of the anaerobic digestion tank to the appropriate temperature using a heating means is because the inner circulation pipe 22 directly contacts the outside air from the outside of the digester to heat the inner circulation pipe 22. The temperature of the organic waste can be controlled to be the same as the temperature in the anaerobic digester.

More specifically, even in summer, the outside air temperature is around 35 degrees, and in winter, the temperature drops to minus 20 degrees, and the temperature of the organic waste flowing in the internal circulation pipe 22 changes rapidly, and the amount of gas inside the digester rather than the amount of gas generated. In addition, since the temperature change is more sensitive to the change in temperature in the case of high temperature digestion, the temperature change of the organic waste flowing in the internal circulation pipe 22 using the heating pipe 32 is the same as the temperature in the anaerobic digestion tank. Will be adjusted.

Thus, the surface temperature of the heating tube is maintained at 20 ~ 60 ± 10 ℃, but slightly higher than the inner circulation pipe, so that the organic waste circulating in the inner circulation pipe is also heated to 20 ~ 60 ± 10 ℃ level.

As described above, by circulating the organic waste from the bottom to the top according to the internal circulation means of the present invention, scum generated in the gas-liquid boundary layer in the anaerobic digestion tank can be drawn into the liquid part and easily removed, thereby generating in the anaerobic digestion process. The digestion gas can be easily moved to the gas part to increase the generation and collection efficiency of the digestion gas, and also increase the contact time and the number of digestion gas generating microorganisms and the organic waste through smooth agitation of the organic waste to increase the amount of digestion gas generated. Can be increased.

[Description of the code]

10: anaerobic digester

12: external inlet

13: external outlet

14: extinguishing gas outlet

16: internal outlet

18: internal inlet

20: internal circulation means

22: internal circulation pipe

24: internal circulation pump

30: heating means

31: coolant tank

32: heating tube

33: supply side circulation line

34: discharge line circulation line

35: coolant circulation pump

36: heater

37: controller

40: stirrer

Claims

An anaerobic digestion tank 10 in which an external inlet 12 is formed at one side to fill a predetermined amount of organic waste, and an extinguishing gas outlet 14 through which the extinguishing gas of the organic waste is discharged;
Internal circulation means (20) for internally circulating the organic waste in the anaerobic digester (10) up and down while repeating the recycling operation of discharging the organic waste filled in the anaerobic digester (10) to the bottom and resupplying to the upper portion;
Heating means 30 for heating the organic waste flowing from the lower portion of the anaerobic digestion tank 10 to the upper portion along the inner circulation means 20 to an appropriate temperature;
Anaerobic digestion equipment having an internal circulation device for removing scum and increasing the amount of digestion gas generated, characterized in that configured to include.
The method according to claim 1,
The anaerobic digestion system having an internal circulation device for scum removal and digestion gas generation, further comprising a stirrer 40 rotatably arranged in the anaerobic digestion tank 10 to stir the organic waste to be circulated. .
The method according to claim 1,
The internal circulation means 20 is:
An inner circulation pipe 22 connecting the inner outlet 16 formed in the lower portion of the anaerobic digester 10 and the inner inlet 18 formed in the upper portion thereof;
An internal circulation pump 24 which pumps and supplies the organic waste discharged from the internal outlet 16 toward the internal inlet 18;
Anaerobic digestion equipment equipped with an internal circulation device for scum removal and increase the amount of digestion gas generated, characterized in that consisting of.
The method according to claim 1,
The heating means 30:
A coolant tank 31 for storing coolant;
A heating tube 32 mounted to an outer diameter or an inner diameter of the inner circulation pipe 22 of the inner circulation means;
A supply side circulation line 33 connected between an outlet of the coolant tank 31 and an inlet of the heating tube 32;
A discharge side circulation line 34 connected between an inlet of the coolant tank 31 and an outlet of the heating tube 32;
A coolant circulation pump 35 mounted on the supply-side circulation line 33 to circulate the coolant in the coolant tank 31 to the heating pipe 32;
A heater 36 mounted in the coolant tank 31 to heat the coolant for temperature control of the coolant;
A controller 37 for controlling an operation period and a time of the heater 14 to adjust the coolant temperature in the coolant tank 31;
Anaerobic digestion equipment having an internal circulation device for scum removal and increase the amount of digestion gas generated, characterized in that configured to include.
The method according to claim 4,
The heating pipe 32 is anaerobic digestion equipment having an internal circulation device for scum removal and increase the amount of extinguishing gas generated by maintaining the surface temperature of 20 ~ 60 ± 10 ℃ by the refrigerant or fruit flowing therein.
The method according to claim 1,
During the operation of the anaerobic digestion tank 10, the stirring for the organic waste is made continuously, the internal circulation of the organic waste by the internal circulation means 20 is made intermittently, the size, internal circulation of the anaerobic digestion tank 10 An anaerobic digestion apparatus having an internal circulation device for removing scum and increasing digestion gas production, characterized in that the number and time of internal circulation of organic waste are determined in consideration of the performance of the pump 24 and the amount of scum generated.