JPS60222197A - Methane fermentation device - Google Patents

Abstract

PURPOSE:To effect satisfactory methane fermentation by changing automatically the temp. of the digesting liquid in a methane fermentation chamber by a heat exchanger in quick response with the change in the temp. of a methane fermentation device thereby controlling adequately the temp. of the digesting liquid in the methane fermentation chamber. CONSTITUTION:The heat exchanger 4 is disposed in the methane fermentation chamber 2 and a heat medium is passed through a piping route 3 including the heat exchanger 4. A control device 9 is so provided as to control the temp. of the heat medium in the route 3 by receiving the signal from a detector 5 which detects the temp. of the digesting liquid in the chamber 2. A selector valve 7 for feed water and a selector valve 8 for discharge which are changed over by the device 9 are provided to the route 3. The digesting liquid in the methane fermentation chamber is thus adequately controlled and the satisfactory methane fermentation is effected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in a methane fermentation apparatus for the purpose of treating organic waste.

Conventional structure and its problems In a methane fermentation device that processes organic waste, 3
So', a container made with mesophilic bacteria that has an optimal temperature around 6°C.
There are two types of methane fermentation equipment: methane fermentation equipment that uses thermophilic bacteria with an optimal temperature around c, but methane fermentation equipment that uses mesophilic bacteria is common because temperature control is relatively easy. By the way, this mesophilic bacterium has 4
It is known that when the temperature exceeds 0'Q, the activity deteriorates extremely and the species die. However, if a methane fermentation device installed outdoors is exposed to direct sunlight in the summer, the temperature of the digestive fluid inside the methane fermentation tank often rises to 40°C or higher. For this reason, it is necessary to cool the mesophilic bacteria in the methane fermentation plant to an appropriate temperature of 35°C in some way. The purpose of the present invention is to provide a methane fermentation device that performs the following steps.

Structure of the Invention The methane fermentation apparatus of the present invention includes a methane fermentation tank, a heat exchanger disposed in the methane fermentation tank, a piping path including the heat exchanger, and a temperature control system for the digestive fluid in the methane fermentation tank. A detector for detecting, a control device for controlling the temperature of the heat medium in the piping route in response to a signal from the detector, and a water supply switching valve and a drainage switching valve that are provided in the piping route and are switched by the control device. It is designed to appropriately control the temperature of the digestive fluid and perform efficient methane fermentation.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings.

In the figure, 1 is a digestive fluid that performs methane fermentation containing mesophilic bacteria, 2 is a methane fermentation tank that stores the digestive fluid 1, 3 is a piping path through which a heat medium flows, and 4 is a part of the piping path 3. This heat exchanger is placed inside the methane fermentation tank 2 and raises and lowers the temperature of the digestive fluid 1. 5 is digestive fluid 1
6 is a pump that is part of the piping route 3 and supplies the heat medium to the heat exchanger 4; 7 is an electromagnetic water supply that switches the heat medium to the heat exchanger 4; A switching valve 8 is an electromagnetic drainage switching valve that switches the heat medium from the heat exchanger 4; 9 is a control device that operates according to the temperature of the digestive fluid 1 detected by the detector 6; The water supply switching valve 1 and the drain switching valve 8 are controlled to switch the heat medium to hot water or cold water. 1o is a gas boiler that burns fermentation gas from the methane fermentation tank 2 to heat a part of the piping route 3 to obtain a hot water heat medium, and the gas piping with the methane fermentation tank 2 is omitted. A water supply device 11 supplies a heat medium of cold water, and is connected to the water supply switching valve 7.

In FIG. 2, 12 is a high temperature comparator that turns ON when the voltage signal from the detector 6 indicates, for example, 38°C or higher;
3 is a first relay which is driven by the high temperature comparator 13 and controls the pump 6, water supply switching valve 7 and drain switching valve 8; 14 is a first relay which is turned on when the detector 6 indicates a temperature below 36°C
15 is a second relay that is driven by the low temperature comparator 14 and controls the pump 6 and the gas boiler 1o; 16 is a control transformer; and GO 7 is a voltage lowered by the control transformer 16. It is a DC constant voltage power supply that converts voltage to DC and supplies DC voltage to subsequent control circuits.

Next, a detailed explanation of the methane fermentation apparatus will be given with reference to FIGS. 1 and 2.

If the temperature of the digestive fluid 1 is appropriate for the activity of mesophilic bacteria (36°C), the control device 9 will not send a signal to any equipment, the pump 6 and the gas boiler 1o will be in a stopped state, and therefore the piping route will be No heat medium flows inside the chamber.

Next, if the detector 5 detects that the temperature of the digestive fluid has increased due to direct sunlight in summer or the influence of high temperature outside air, for example, 38°C or higher, the controller 9 The high temperature comparator 12 changes from the OFF state to the ON state, and the first
The switching valve 7 switches the piping route from the boiler 1o side to the water supply device 11 side, and the drain switching valve 8 switches the piping route from the boiler 1o side to the drain side.
1 flows into the heat exchanger 4 and begins to lower the temperature of the digestive fluid 1 in the methane fermentation tank 2 and is discharged from the drainage switching valve 8. When the digestive fluid 1 reaches, for example, 366C, the high temperature comparator 1
2 returns to the OFF state and turns off the relay 13.
, the pump 6 is stopped, and the water supply switching valve 7 and drainage switching valve 8 are also closed.
It becomes FF, and the piping route 3 returns to the gas boiler 1o side.

Next, when the temperature of the outside air decreases and the detector 5 detects that the temperature of the digestive fluid 1 falls below, for example, 35°C, the low temperature comparator 14 in the control device 9 changes from the OFF state to the ON state. Become. As a result, the second relay 15 is operated to drive the pump 6, and at the same time, the gas boiler 10 is also driven to combust the fermentation gas. Hot water is produced by this combustion, and the hot water is sent as a heat medium from the pump 6 to the heat exchanger 4 via the water supply switching valve 7 to heat the digestive fluid 1. The heat medium that has been heated by the heat exchanger 4 is returned to the gas boiler 1o via the drainage switching valve 8. The returned water is heated by the gas boiler 1o and supplied to the heat exchanger 4 again, where the digestive fluid 1 is heated. The detector 5 detects that the temperature of the digestive fluid 1 has exceeded 36°C due to continued heating.
If detected, the low temperature comparator 14 returns to OFF, the relay 15 also turns OFF, the pump 6 and the gas boiler 10 are stopped, and heating ends.

In addition, although water was used as a heat medium and was heated by a gas boiler in the example, it is clear that the present invention is not necessarily limited to this example.

Effects of the Invention The methane fermentation device of the present invention constantly detects the temperature state of the digestive fluid in the methane fermentation tank using a detector, and activates the control device when the temperature of the digestive fluid in the methane fermentation tank becomes too hot. The heat exchanger acts as a cooler and suppresses the temperature rise of the digestive fluid.If the digestive fluid is about to drop to a low temperature, the control device operates and switches the heat exchanger to a warmer to lower the temperature of the digestive fluid. It also suppresses the decline. Therefore, the heat exchanger can automatically and quickly respond to changes in temperature, contributing to good methane fermentation. Also, since it is automatic, it saves time and effort, making it extremely practical.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a methane fermentation device showing an embodiment of the present invention, and FIG. 2 is a control circuit diagram of the device. 2...Methane fermentation tank, 3...Mountain piping route, 4
...Heat exchanger, 5...Detector, a...
...Water supply switching valve, 8...Drainage switching valve, 9
······Control device. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] A methane fermentation tank, a heat exchanger placed in the methane fermentation tank, a piping route including the heat exchanger, a detector for detecting the temperature of the digestive fluid in the methane fermentation tank, and a signal from the detector. A methane fermentation device comprising: a control device for controlling the temperature of a heat medium in the piping route based on the received water; and a water supply switching valve and a drainage switching valve that are provided in the piping route and are switched by the control device.