JPH0592180A - Apparatus and method for treating garbage - Google Patents

Abstract

PURPOSE:To reduce the volume and amount of garbage while preventing the spoilage thereof and to reutilize the garbage as a raw material for fertilizer or feed. CONSTITUTION:A garbage treatment apparatus has a garbage grinding and dehydrating device 3, a dryer 4 drying the ground and dehydrated garbage, the drying blow pipe 15 and drying exhaust pipe 16 connected to the dryer 4 and a heat exchanger 10 for heating the air flowing through the drying blow pipe 15 by the air heated by a burner 11 and combustion quantity is controlled on the basis of the temp. in the drying blow pipe 15 and the water activity of garbage is controlled on the basis of the temp. in the drying exhaust pipe 16 to grasp a drying state.

Description

Detailed Description of the Invention

[0001]

[Field of Industrial Application] The present invention aims to reduce the volume and quantity of food waste produced from food factories, hotels, restaurants, apartments, etc., prevent spoilage of the food waste, and fertilize the food waste. The present invention relates to a food waste processing device and a processing method for making it reusable as a raw material such as feed.

[0002]

2. Description of the Related Art In recent years, food waste generated from food factories, hotels, restaurants, multi-dwelling houses, etc. has caused problems on the user side such as the occurrence of decay, an increase in the garbage storage area, and an increase in the amount of waste collected by processors. Yes, the treatment company side has problems such as collection, transportation cost increase, labor shortage, etc., and the local government side has problems such as incinerator and landfill measures,
Reducing the volume and quantity of raw garbage has become a major issue. For this reason, conventionally, as a device to be processed by a user with a simple structure, for example, a device for crushing, dehydrating, and bagging food waste has been developed which is a hygienic means and reduces the volume.

[0003]

However, in the above-mentioned conventional food waste processing apparatus, the weight of the food waste is heavy and the transportation cost is not reduced due to the presence of water in the food waste, and the food waste is easily decomposed. Therefore, there is a problem that the environment is adversely affected. Further, because of these problems, it has been difficult to make them reusable as raw materials such as fertilizers and feeds.

The present invention solves the above problems and aims to reduce the volume and amount of food waste, prevent spoilage, and reuse raw materials for fertilizers, feeds, etc. It is an object to provide a waste treatment device and a treatment method.

[0005]

To this end, the apparatus for treating food waste according to the present invention is a crushing and dehydrating device 3 for crushing and dehydrating food waste.
The dryer 4 for drying the crushed and dehydrated food waste, the drying air blow pipe 15 and the drying air discharge pipe 16 connected to the dryer 4, and the drying air blow pipe 15 by the air heated by the burner 11. Heat exchanger 1 for heating flowing air
It is characterized by having 0 and.

[0006] The method of treating food waste according to the present invention comprises a crushing / dewatering device 3 for crushing and dehydrating food waste, a dryer 4 for drying the crushed and dehydrated food waste, and a blowing air for drying connected to the dryer 4. It has a pipe 15 and a discharge pipe 16 for drying, and a heat exchanger 10 for heating the air flowing through the drying blower pipe 15 by the air heated by the burner 11, and burns at the temperature in the drying blower pipe 15. It is characterized by controlling the amount and controlling the water activity of food waste by the temperature in the drying discharge pipe 16 to grasp the dry state.

It should be noted that the numbers added to the above configuration are for comparison with the drawings for easy understanding, and the configuration of the present invention is not limited by this.

[0008]

In the present invention, for example, as shown in FIG. 1, raw garbage is crushed and dehydrated by the crushing and dehydrating device 3 and sent to the dryer 4, while the outside air is blown by the blower fan 12
The high-temperature air sent to the burner 11 via the combustion blower pipe 14 and to the heat exchanger 10 via the drying blower pipe 15 and heated by the burner 11 is sent to the heat exchanger 10 via the exhaust pipe 17. The air sent and heated in the drying blower pipe 15 is heated, the heated air is sent into the drying container 5 to heat the food waste, and the moist air which has absorbed the moisture of the food waste passes through the drying discharge pipe 16. It is sent to the burner 11 and used as combustion air. Then, in order to dry the water activity to a predetermined value, the temperature detector T in the drying blower pipe 15
The amount of combustion is controlled at the temperature of C1 and the water activity of the food waste is controlled at the temperature of the temperature detector TC2 in the drying discharge pipe 16 to grasp the dry state.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the food waste processing apparatus of the present invention.

In the figure, 1 is a hopper for throwing food waste, 3 is a crushing dehydrator, 4 is a dryer having a hot air passage 6 around a drying container 5, and a rotary shaft 21 driven by a motor therein.
And a stirring device 7 having a cutting blade 22 provided on the rotary shaft 21. Reference numeral 8 is an opening / closing device, 9 is a waste container or collection bag, 10 is a heat exchanger, 11 is a burner, and 12 is a blower fan.

The blower fan 12 is connected to the burner 11 by a combustion blower pipe 14 and also the drying blower pipe 1
5 is connected to the lower part of the drying container 5 via the heat exchanger 10. A discharge pipe 16 for drying is connected between the upper portion of the drying container 5 and the burner 11, and is connected to the burner 11. The exhaust pipe 17 of the burner 11 is connected so as to be exhausted via the heat exchanger 10, and the drying blower pipe 15 and the drying discharge pipe 16 are respectively provided with temperature detectors TC1 and T1.
C2 is provided.

The food waste processing method of the present invention having the above-mentioned structure will be described. The garbage is put into the hopper 1 and crushed and dehydrated by the crushing and dehydrating apparatus 3. Next, the food waste is sent into the dryer 4 and stirred by the stirring device 7 in the drying container 5. The food waste dried in the drying container 5 is opened and closed by the opening / closing device 8
The container is stored in the garbage container or the collection bag 9 by opening.

On the other hand, the outside air is sent by the blower fan 12 to the burner 11 through the combustion blower pipe 14, and
It is sent to the heat exchanger 10 via the drying blower pipe 15. The high-temperature air heated by the burner 11 is sent to the heat exchanger 10 via the exhaust pipe 17, heats the air flowing through the drying blast pipe 15, and sends the heated air into the drying container 5. The hot air is adiabatically cooled by coming into contact with food waste in the drying container 5, and the outlet air temperature of the dryer 4 becomes constant in a steady state. The food waste is heated to lower the water activity, the outlet air temperature of the dryer 4 rises, and the moist air that has absorbed the water content of the food waste is sent to the burner 11 via the discharge pipe 16 for drying and used as combustion air. At the same time, most of the odor contained in the air is decomposed by heating by the burner 11 and then discharged to the outside. Note that a deodorizing device may be provided in the exhaust system so that the exhaust gas is deodorized by the deodorizing device.

By the way, the food waste is a mixture of various foods, and the factors of spoilage and odor generation thereof differ depending on the water activity aw of each food. Here, the water activity aw is aw = water vapor pressure of food / saturated water vapor pressure of air. It is said that it is preferable to dry so that the water activity aw becomes about 0.2 to 0.6. This is because if the water activity is too low, the deterioration of the lipid is promoted by the oxidation of the lipid. Therefore, in order to dry the water activity to a predetermined value, in the present invention, the combustion amount is controlled by the temperature of the temperature detector TC1 in the drying blower pipe 15, and the temperature detector in the drying discharge pipe 16 is controlled. The feature is that the dry state is grasped at the temperature of TC2.

This will be described with reference to FIG. FIG. 2 shows a moist air diagram, where t is the dry-bulb temperature ° C, x is the absolute humidity, and ψ is the relative humidity.

If the water activity of food waste is to be dried up to 0.3, the discharge pipe 16 for drying is discharged from the drying container 5.
The relative humidity of the moist air inside may be set to 30%. For example, the temperature of outside air is 30 ° C and the relative humidity is 80% (A in the figure
Point), this is heated to 120 ° C. along the iso-absolute humidity line B in the heat exchanger 10 (point C in the figure), and is cooled along the adiabatic cooling line D in the drying container 5 in a steady state. Then 40
It becomes saturated air at point E in ° C. When food waste is heated and the water activity decreases, the outlet air temperature rises and the relative humidity becomes 30%.
The temperature of 62 ° C. at the point F intersecting with the temperature becomes the temperature of the temperature detector TC2 in the drying discharge pipe 16. That is, in order to set the water activity of raw garbage to 0.3, the combustion amount of the burner 11 should be controlled by the temperature of the temperature detector TC1 so that the temperature of the temperature detector TC2 becomes 62 ° C. ..

3 and 4 show another embodiment of the food waste processing apparatus of the present invention, FIG. 3 shows an example in which a fan 12 for a dryer and a combustion fan 12 'are provided separately, and FIG. Shows an example in which combustion air to the burner 11 is sent only from the dryer 4.

FIGS. 5, 6 and 7 show the experimental results in the embodiment of FIG. FIG. 5 shows the relationship between the dryer inlet temperature and the thermal efficiency. The thermal efficiency here is the ratio of the latent heat of vaporization at the dryer outlet to the total heat at the dryer inlet. According to this, it was found that the thermal efficiency is high when the dryer inlet temperature is 100 to 300 ° C., preferably about 200 ° C., and therefore the drying time is shortened. The reason why the thermal efficiency decreases with increasing temperature is that the heat loss from the wall surface increases.

FIG. 6 shows the relationship between the air volume per volume of the drying container 5 and the thermal efficiency. According to this, the air volume per volume (m
It has been found that the thermal efficiency is high when ³ / hm ³ ) is 1.2 × 10 ^{3 to} 3.0 × 10 ³ , preferably about 1.7 × 10 ³ .

FIG. 7 shows the relationship between the agitation rotation speed, the dryer heat exchange efficiency and the motor output, and it was found that the heat exchange efficiency decreases when the agitation rotation speed becomes 60 rpm or less. If the stirring speed is increased, the motor output also increases, so adjust the stirring speed to 60 rpm according to the capacity of the motor.
It is good to be above.

As a result of various other experiments, it was found that it is the most difficult to dry the leftover food as raw garbage. This is because when the leftover rice is put in the dryer and stirred, the leftover rice becomes a rice cake-like or pasty-like substance and sticks to the inner surface of the dryer, or only the surface is scorched so that the inside cannot be dried. Therefore, an attempt was made to adopt the above-mentioned control for detecting the dryer outlet temperature and grasping the dried state, and to carry out the stepwise addition while watching the dryer outlet temperature.

Table 1 shows the experimental results of the case where the leftover rice is used as raw garbage and the leftover rice is put into the dryer all at once, and the case where the leftover rice is divided into small portions depending on the outlet temperature of the dryer. In addition, the stirring power is small and the thermal efficiency is high, and the leftover rice does not become sticky or pasty and stick to the inner surface of the dryer, or only the surface is scorched so that the inside cannot be dried.

[0023]

[Table 1]

[0024]

As is apparent from the above description, according to the present invention, since food waste is crushed and dehydrated as a pretreatment for drying,
Water adhering to the surface of food waste is removed and the surface area is increased, so that energy saving and efficiency of drying can be achieved. Further, since it is possible to reduce the volume and the amount of garbage, it is possible to reduce the transportation cost and the storage space.

Further, by using the water activity as a parameter for ascertaining the dry state, it is possible to accurately ascertain the dry quality by a simple method, and the water activity of raw garbage is processed to an appropriate value. It is possible to prevent spoilage and odor generation of food waste, facilitate the storage of food waste, and make it reusable as a raw material such as fertilizer and feed.

By using a heat exchanger as the drying heat source, the gas temperature state of each part can be freely set.

Further, since the air discharged from the dryer is sent to the burner and used as combustion air, most of the odor contained in the air is thermally decomposed by the burner, so that the deodorizing device is unnecessary.

Further, in the case of adopting the divided input of raw garbage, the stirring power is small and the thermal efficiency is high, and the leftover rice becomes sticky or pasty and sticks to the inner surface of the dryer, or only the surface. No longer sticks to the inside and cannot be dried inside.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a food waste processing device of the present invention.

FIG. 2 is a moist air diagram for explaining the method of treating food waste.

FIG. 3 is a configuration diagram showing another embodiment of the garbage processing device of the present invention.

FIG. 4 is a configuration diagram showing another embodiment of the garbage processing device of the present invention.

FIG. 5 is a diagram for explaining an experimental result according to the present invention.

FIG. 6 is a diagram for explaining an experimental result according to the present invention.

FIG. 7 is a diagram for explaining an experimental result according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hopper, 3 ... Crushing dehydrator, 4 ... Dryer, 5 ... Drying container, 7 ... Stirring device 8 ... Opening / closing device, 9 ... Garbage storage container or collection bag, 10 ...
Heat exchanger 11 ... Burner, 12 ... Blower fan, 14 ... Combustion blast pipe 15 ... Drying blast pipe, 16 ... Drying exhaust pipe, 17 ... Exhaust pipe, 21 ... Rotating shaft 22 ... Cutting blade, TC1, TC2 ... Temperature detector

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[Procedure amendment]

[Submission date] May 20, 1991

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

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[Figure 1]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

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[Figure 5]

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 6

[Correction method] Change

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[Figure 6]

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

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[Figure 7]

Claims (2)

[Claims] 1. A crushing and dehydrating apparatus for crushing and dehydrating food waste, a dryer for drying the crushed and dehydrated food waste, a drying blower pipe and a drying discharge pipe connected to the dryer, and a burner. And a heat exchanger for heating the air flowing through the drying blower pipe with heated air. 2. A crushing and dehydrating apparatus for crushing and dehydrating food waste, a dryer for drying the crushed and dehydrated food waste, a drying blower pipe and a drying discharge pipe connected to the dryer, and a heater for heating. It has a heat exchanger for heating the air flowing through the drying blast pipe with the air, and controls the combustion amount of the burner by the temperature inside the drying blast pipe, and the moisture in the food waste depending on the temperature inside the drying discharge pipe. A method for treating food waste, which comprises controlling the activity and grasping the dry state.