JPS6359397A - Methane fermentation apparatus - Google Patents

Abstract

PURPOSE:To enhance methane fermentation efficiency, by fixing porous bacteria nests immobilizing bacteria in a fermentation tank in a shakable manner and providing an aeration stirring means to the fermentation tank. CONSTITUTION:Waste is charged in a fermentation tank 1 from a charge port 6 and stirred by air bubbles discharged from an aeration port 5 to be decomposed in the fermentation tank 1. A part of decomposition gas is taken out as fermentation gas from a gas take-out port 9 to be utilized in energy and a part of said gas is returned to the fermentation tank 1 as aeration gas and the remainder is utilized in the promotion of propagation of bacteria. The bacteria in a fermentation liquid are adhered to bacteria nests 2 to propagate and the concn. of bacteria in the fermentation tank is enhanced. A part of fermentation gas is returned to the fermentation tank by a pump 4 and discharged as gas bubbles from the aeration port 5. By this method, a gas-liquid contact surface is increased and a methane gas generating speed rises.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a methane fermentation device that processes organic waste using microorganisms and uses the generated methane gas as an energy source.

Conventional technology In order to increase the fermentation efficiency of methane fermentation, it is necessary to: ■ increase the concentration of microorganisms that perform methane fermentation; Three points are necessary: optical stirring, and (1) increasing the gas-liquid contact area as much as possible to increase the rate of methane gas generation.

Conventionally, in order to increase the concentration of microorganisms, a fixed bed was installed in the fermenter, fine spherical substances were placed in the fermenter, or powdered substances such as clay were added. By taking these measures, microorganisms will adhere to each substance and their concentration will increase.

Problems to be Solved by the Invention However, in the case of the above-mentioned fixed bed, the bed is literally fixed, so sufficient stirring within the fermenter cannot be achieved. In addition, if a mesh-like spherical material is placed in the tank, when the concentration of microorganisms increases and the amount of gas generated increases, this material will be filled with methane gas and the spherical material will rise to the surface of the liquid, causing microorganisms and organic waste. Not only does this interfere with the mixing of materials, but equipment troubles are more likely to occur. Furthermore, in the case of powdered substances such as clay, this substance rapidly flows out of the tank due to stirring, etc., so that the flow-out amount must be constantly replenished in order to maintain the microbial concentration.

As described above, even if the conventional method can increase the concentration of microorganisms, it cannot satisfy the other requirements for increasing the fermentation efficiency of methane fermentation.

The present invention solves these problems and improves the efficiency of methane fermentation by improving the efficiency of methane fermentation through the following three points: trenching, increasing microorganism concentration, sufficient mixing of microorganisms and organic waste, and gas-liquid It is an object of the present invention to provide a methane fermentation device that effectively increases the contact surface.

In order to achieve more than a means for solving the problems, the present invention fixes microorganisms in a fermenter.The microorganisms are fixed to the fermenter in a swingable manner using a flexible fixing material, and are stirred by an aeration stirring means. It was designed to do this.

Effects In the present invention having the above configuration, the microbial nest is fixed in a swingable manner in the fermenter using a flexible fixing material, so that the microbial concentration increases. Since it is fixed so that it can swing, it does not reduce the mixing efficiency in the tank. Furthermore, aeration and stirring increase the gas-liquid contact area.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Inside the fermenter 1, there is a microbial nest 2 that increases the microbial concentration.
A flexible thread-like fixing material 3 made of swingable and freely bendable fibers fixes the microorganism nest 2 (made of porous synthetic resin or metal molded into a spherical shape as a whole) in the fermenter 1 It has The fermenter 1 also includes a pump 4 which returns the fermentation gas to the inside of the fermenter 1 and aerates the gas.
It is equipped with an aeration stirring means consisting of an aeration port 5, a pipe 8, and the like. In the figure, 6 is an inlet for organic waste, 7 is an overflow outlet connected to a waste liquid treatment tank, and 9 is a gas outlet connected to a gas utilization device.

In the above device, the organic waste introduced through the input port 6 is agitated by air bubbles released from the aeration port 5 and decomposed in the fermenter 1, and a portion is also taken out as fermentation gas through the gas outlet 9. A portion of the gas is used for energy, and a portion is returned to the fermenter 1 as aeration gas, and the remainder is used to encourage the growth of microorganisms. The microorganisms in the fermentation liquid adhere to the microbial nest 2 and multiply, so the concentration of microorganisms in the fermenter 1 increases. Since this microbial nest 2 is fixed in the fermenter 1 with a flexible thread-like fixing material 13 that can be freely swung, it will not flow out of the fermenter, and there is a risk that stirring inside the fermenter will be incomplete. Nor.

A part of the generated fermentation gas is returned into the fermenter by the pump 4, and is released as bubbles from the plurality of aeration ports 5, thereby stirring the inside of the fermenter. Therefore, the gas-liquid contact area increases.

Effects of the Invention As described above, according to the present invention, microorganisms are immobilized by the microbial nest, and the microbial nest is also fixed in the fermenter, so the concentration of microorganisms in the tank increases and the activity of methane fermentation increases. Rise. Since the microbial nest is fixed in a swingable manner using a flexible fixing material, the agitation effect in the fermenter caused by aeration is not weakened. Furthermore, the rate of methane gas generation increases due to the increase in the gas-liquid contact surface due to aeration and stirring. Therefore, methane fermentation is carried out efficiently, and the size of the fermenter can be reduced accordingly.

[Brief explanation of drawings]

The figure is a longitudinal sectional view of a methane fermentation apparatus showing one embodiment of the present invention. 1...Fermentation tank, 2...Microbial nest, 3.
・Mark: Fixing material, 4: Pump, 5: Mark: Aeration port.

Claims (1)

[Claims] A methane fermentation device in which a large number of porous microbial nests for fixing microorganisms that perform methane fermentation are fixed in a fermenter so as to be able to swing in large numbers using flexible fixing materials, and the fermenter is equipped with an aeration agitation means.