JP4848549B2 - Method and apparatus for drying food waste - Google Patents

Description

The present invention is a convenience store, a remaining lunch from a store, a department store or a hotel, an edible garbage discharged from a factory or a household (food bowl, leftovers, bento, okara, fish gutter or bone, oil cake, The present invention relates to a drying method and apparatus for miso koji and other animal or animal edible foods that can be used as animal feed.

Fertilizer that drys raw garbage at around 100 ° C for 4-6 hours, adjusts the moisture content to 10% and removes it, then removes aluminum and iron, and further adds nitrogen fertilizer or chicken manure or sewage sludge Is described in Patent Document 1.
In addition, Patent Document 2 discloses a method for producing sludge by heating, pressurizing, and stirring with high-temperature and high-pressure steam without separating plastic rice, wood scraps, paper, etc. A method and apparatus for treating garbage that is sprayed, stirred, dried and cooled to produce a fine sterilized fertilizer has been proposed.

JP 2001-151585 A JP 2003-164826 A

However, in the techniques described in Patent Documents 1 and 2, since the final product is a fertilizer, the product unit price is low and the product has a relatively low added value. Moreover, even if the techniques described in Patent Documents 1 and 2 are used, there is a problem in that it cannot be used as livestock feed because it contains plastic film, wood chips, paper, and the like.
Therefore, the present inventor considered that a product with high added value can be obtained by taking out an edible portion contained in raw garbage and adding it to a part of livestock feed. Here, it was confirmed that if air for drying (hot air) was made from a normal heat source and edible garbage was dried using this hot air, a product that would become part of livestock feed could be produced. The problem of inefficiency occurred.

The present invention has been made in view of such circumstances, and a method for drying food waste that can produce a product that is part of livestock feed, as well as raw materials for fertilizer, from edible raw waste with a relatively low production cost, and An object is to provide an apparatus.

The method for drying food waste according to the first invention in accordance with the above object is a method for drying food waste discharged from a home or a company,
A first step of drying the food waste with high temperature steam, a second step of drying the food waste dried in the first step with hot air using high temperature steam as a heat source, and a food waste dried in the second step A third step of drying with superheated steam of 105 ° C. or more and 500 ° C. or less, and the high-temperature steam used in the first step and the hot air used in the second step. As a heat source. Therefore, the temperature and amount of superheated steam supplied in the third step so that the temperature of the steam used in the third step becomes 90 ° C. or higher (more preferably 100 ° C. or higher, more preferably 105 ° C. or higher). To control.

Moreover, the food waste drying apparatus according to the second invention is a drying device for food waste discharged from a home or company having first to third drying chambers through which the food waste passes by the transport means,
A superheated steam supply source for supplying high-temperature superheated steam of 105 ° C or higher and 500 ° C or lower;
In the third drying chamber, a superheated steam ejection nozzle that ejects high-temperature superheated steam from the superheated steam supply source and sprays the food waste in the third drying chamber;
Air blown in the second drying chamber for blowing hot air heated by a heater that heats air using the high-temperature steam discharged from the third drying chamber as a heat source to the food waste in the second drying chamber Means,
A steam ejection nozzle is provided in the first drying chamber for blowing high temperature steam discharged from the third drying chamber to the food waste in the first drying chamber.
Here, the conveying means refers to, for example, a belt conveyor, a net conveyor, a slat conveyor using a large number of rectangular plates, a screw conveyor, a ribbon conveyor, a chain conveyor, a rotationally driven spiral blade (scraper), and the like.

In the food waste drying apparatus according to the second invention, the superheated steam jet nozzle in the third drying chamber sprays superheated steam from above and below the food waste that is gradually transported by the transport means. preferable.
In the food waste drying apparatus according to the second aspect of the present invention, it is preferable that the steam ejection nozzle in the first drying chamber blows high-temperature steam from above and below the food waste placed on the conveying means.

In the food waste drying apparatus according to the second aspect of the present invention, the conveying means passes through at least two of the first to third drying chambers. Therefore, the case where one conveyance means has penetrated the 1st-3rd drying chamber is also included.
Furthermore, individual conveying means may be provided in each of the first to third drying chambers.
In the above invention, when food waste as a raw material contains non-edible substances such as plastic, paper, metal, wood, or ceramic, it is preferable to sort in advance.

In the method for drying food waste according to claim 1, the food waste is dried with superheated steam of 105 ° C. or more and 500 ° C. or less in the third step, and a part of the exhaust gas (that is, used steam) is dried in the first step. Since it is used as it is and used as a heat source for dry air (hot air) in the second step, the superheated steam can be effectively used, and the amount of fuel used as a whole is reduced.
Furthermore, in addition to the drying of food waste to some extent in the first step, it is sterilized by high-temperature heating, and the promotion of decay can be stopped.
Further, since drying is performed with high-temperature superheated steam, the steam content finally becomes water, and exhaust gas treatment is minimized. Furthermore, food waste can be sterilized and heat treatment (denaturation of starch and protein) can be performed.

Further, the food waste drying apparatus according to any one of claims 2 to 5 uses the superheated steam used in the third drying chamber as a heat source in the first drying chamber, and as a heating source of dry air in the second drying chamber. Therefore, the heat contained in the superheated steam can be used effectively.
In particular, in the first drying chamber, raw steam is applied to preliminarily dry, sterilize and preheat food waste. In the second chamber, food waste is dried with dry air (hot air), so the second drying chamber. Then steam is not humidified. Moreover, since the superheated steam used in the third drying chamber is 105 ° C. or more and 500 ° C. or less, the moisture contained in the food waste is vaporized and sufficiently dried.

4. The food waste drying apparatus according to claim 3, wherein the superheated steam jet nozzle in the third drying chamber blows superheated steam from above and below the food waste placed on the conveying means, so that drying can be performed efficiently.

In the food waste drying apparatus according to the fourth aspect, the steam ejection nozzle in the first drying chamber blows high-temperature steam from above and below the food waste placed on the conveying means, so that drying can be performed efficiently.
In the food waste drying apparatus according to the fifth aspect, since the same conveying means is inserted into at least two drying chambers, the apparatus can be simplified.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is an explanatory view of a food waste drying apparatus according to the first embodiment of the present invention, and FIG. 2 is an explanatory view of a food waste drying apparatus according to the second embodiment of the present invention. .

As shown in FIG. 1, the food waste drying apparatus 10 according to the first embodiment of the present invention includes tunnel-type first to third drying chambers 11 to 13 arranged in a straight line, Screen conveyor (or a net frame on which food waste can be mounted), which is an example of a transport means for sequentially and sequentially transporting food waste 14 discharged from a home or company to the central positions of the first to third drying chambers 11 to 13 (It may be a chain conveyor or a slat conveyor in which containers are arranged side by side.) 15 and a superheated steam supply source 16 which is a heat supply source of the first to third drying chambers 11 to 13. These will be described in detail below.

The first to third drying chambers 11 to 13 are configured in a tunnel shape, and the left and right side surfaces, the ceiling surface, and the bottom surface are covered with a heat insulating material to sufficiently maintain heat. Except for the part through which the screen conveyor 15 passes and the part through which the food waste 14 mounted on the screen conveyor 15 passes at the entrance and exit of each of the first to third drying chambers 11 to 13, the outside is covered with a heat insulating material. A covered openable cover is provided.
The lengths of the first to third drying chambers 11 to 13 may be the same, but the speed of the screen conveyor 15 is the same in any drying chamber. It is preferable to provide it. In this embodiment, for example, the third drying chamber 13> the second drying chamber 12> the first drying chamber 11 is set.

The screen conveyor 15 includes a driving roller 17 on the front side of the third drying chamber 13 and a driven roller 18 on the rear side of the first drying chamber 11. The driven roller 18 is provided with a tension mechanism (not shown) and applies a constant tension to the endless screen 19 that is always stretched. Further, the endless screen 19 is provided with a linear material having a sufficient strength at an interval of 10 to 30 cm, and guide members (not shown) are provided on both sides of the endless screen 19 so that the endless screen 19 has food waste. Even if 14 is put, it does not sag. The endless screen 19 is made of a stainless steel net having an opening degree of 0.1 to 1.5 mm, for example, and has a structure that prevents the food waste 14 placed thereon from dropping down.

The third drying chamber 13 is sprayed with high-temperature superheated steam of 105 to 500 ° C. (more preferably 200 to 300 ° C.) from the superheated steam supply source 16 on the food waste 14 placed on the screen conveyor 15. The superheated steam jet nozzles 20 and 21 are provided above and below the screen conveyor 15 with a gap. The superheated steam jet nozzles 20 and 21 are made of metal pipes, and a plurality of steam jet holes are provided on the lower side and the upper side, respectively. In this embodiment, the superheated steam jet nozzles 20 and 21 are arranged three above and below, but may be two or four or more. Moreover, although each superheated steam injection nozzle 20 and 21 is arrange | positioned up and down, you may arrange | position alternately by changing the position in a conveyance direction. The superheated steam jet nozzles 20 and 21 are provided in a region (entrance side and center) excluding the outlet side of the third drying chamber 13, and an exhaust duct 22 is provided at the upper outlet side of the third drying chamber 13. Yes.

The superheated steam supply source 16 includes a steam generator 24 and a steam heater 25 and generates high-temperature superheated steam. The supply amount is determined by the size and structure of the third drying chamber 13, the amount of food waste to be dried, and the moving speed, and the temperature of the steam discharged from the exhaust duct 22 is more preferably 90 ° C. or more. The temperature should be 100 ° C. or higher, more preferably 105 ° C. or higher.

In the second drying chamber 12, a steam pipe heater 26 (an example of a heater) and a fan (an example of a blowing unit) 27 are disposed on the upper side of the screen conveyor 15. The steam pipe heater 26 is heated by high-temperature steam supplied from the exhaust duct 22 via the blower 28 and the air volume adjustment valve 29. The fan 27 is provided on the upper side of the steam pipe heater 26. The steam pipe heater 26 heats the air sent by the fan 27, and the food waste 14 conveyed by the screen conveyor 15 is dried by this hot air without being humidified. The fans 27 are arranged in a plurality of rows across the width of the screen conveyor 15.

The air that heated the food waste 14 may circulate in the second drying chamber 12 and be used again as an air source. However, since the humidity rises sequentially, a dehumidifying device is provided in the middle, or a new external It is preferable to bring in dry air. In this case, since an exhaust port is required, it is preferable to use the heat contained in the air discharged from the second drying chamber as a heat source for preheating the air before passing through the steam pipe heater.

In the first drying chamber 11, a plurality of steam ejection nozzles 30 and 31 are provided above and below the screen conveyor 15, respectively. The steam ejection nozzles 30 and 31 are pipes each having a steam ejection hole at a lower position and an upper position. The steam jet nozzles 30 and 31 are supplied with high-temperature steam from the exhaust duct 22 through the blower 32 and the flow rate adjusting valves 33 and 34, and the food garbage 14 directly from the steam jet holes of the steam jet nozzles 30 and 31. High temperature steam can be sprayed on.

A hopper 35 for food waste 14 is provided at the rear part (that is, the entrance side) of the first drying chamber 11. A rotary valve 36 is provided at the bottom of the hopper 35 so that food waste 14 is cut out by a predetermined amount and placed on the screen conveyor 15.
A water receiver 38 is provided below the endless screen 19 on which the food waste 14 is placed from the inlet 37 of the hopper 35 to the entrance of the first drying chamber 11, and the food waste 14 contains water. It has a structure that can be removed. If the food waste 14 does not contain water, the water receptacle 38 can be omitted.

Next, a method for drying food waste using the food waste drying apparatus 10 will be described.
The food waste 14 stored in the hopper 35 is cut out by the rotary valve 36 and placed on the endless screen 19 of the screen conveyor 15. It should be noted that the food waste 14 has previously been removed from containers and packaging materials that cannot be eaten. When water is contained in the food waste 14, this water passes through the endless screen 19 and is collected by the water receiver 38, so that the food waste 14 is made to contain as little water as possible.

When the food waste 14 is transported to the first drying chamber 11, it is preliminarily dried by being heated by high-temperature steam discharged from the steam ejection nozzles 30 and 31. In this case, since the vapor temperature is 90 ° C. or higher (preferably 100 ° C. or 105 ° C. or higher), part of the contained moisture is vaporized. Note that, when heated with a high-temperature steam exceeding 100 ° C., the degree of drying remarkably progresses. Therefore, when the steam temperature is low, high-temperature overheating is directly performed from the heating steam supply source 16 via the bypass line 40 and the valve (valve) 41. Steam can also be added (first step).

When the food waste 14 is conveyed to the second drying chamber 12, it is dried by the airflow heated by the steam pipe heater 26. This high-temperature air stream (hot air) has a sufficiently lower humidity than steam, and dries the food waste 14. When the temperature is low, the superheated steam may be partially supplied to the steam pipe heater 26 directly from the heating steam supply source 16 via the bypass line (with a flow rate adjusting valve 26b) 26a (the second is described above). Process).

When the food waste 14 is supplied to the third drying chamber 13, the dried food waste 14 is dried with superheated steam of 105 ° C. or more and 500 ° C. or less ejected from the superheated steam ejection nozzles 20 and 21. As a result, food waste having a moisture content of 10 to 60% is produced. When the moisture is lower as 10 to 30%, the anti-corruption is further promoted. However, the moisture is transferred from the screen conveyor 15 to another conveyor 45 or once put in a container. The dried food waste can be used as it is or pulverized as an additive for livestock feed. In some cases, it can be crushed into fertilizer (the third step).

Next, a food waste drying apparatus 48 according to a second embodiment of the present invention will be described with reference to FIG. In the figure, “B” indicates a blower (an example of a blowing means), “M” indicates a motor, and “P” indicates a pump.
A food waste drying apparatus 48 according to the second embodiment includes first to third drying chambers 49 to 51 and superheated steam that supplies high-temperature superheated steam of 105 to 500 ° C. to the third drying chamber 51. A supply source 52, a steam heater 54 that generates hot air (high-temperature air) to the second drying chamber 50 with steam sent from the third drying chamber 51 through the dust collector 53, and the second drying chamber 50 A condenser (condenser, ie, dehumidifier) 55 that circulates the hot air inside to lower the humidity is provided.

The first drying chamber 49 includes a raw material charging port 56, and high-temperature steam of 100 to 150 ° C. is discharged from the third drying chamber 51 for food waste that is gradually conveyed by a screw conveyor 57 that is an example of a conveying unit. Is sprayed through a steam jet nozzle (not shown) to dry and sterilize food waste. Used steam is discharged to the outside through an exhaust tower. An emergency exhaust port 58 is also provided. By this first drying chamber 49, food waste containing about 70 to 80% of moisture on average becomes food waste containing 65 to 75% of moisture.

The food waste processed in the first drying chamber 49 is supplied to the second drying chamber 50. The second drying chamber 50 is also provided with a screw conveyor 60 that is an example of a conveying unit that gradually conveys food waste from the inlet toward the outlet.
The heat source of the second drying chamber 50 is hot air of 100 to 150 ° C. generated by the steam heater 54, and the hot air is blown to the food waste through the ejection nozzle. Since the hot air has a low humidity and a high temperature, drying of food waste is promoted. When drying is performed, the humidity of the hot air increases and the drying efficiency decreases. Therefore, the dehumidified hot air (or hot air) is supplied again to the second drying chamber 50 by the condenser 55. Since the temperature of the water supplied to the condenser 55 rises, it is cooled by the cooling tower 61. Further, when the hot air generated by the steam heater 54 is sequentially sent to the second drying chamber 50, excess air is generated and is discharged outside through the exhaust tower. Reference numeral 62 denotes a water storage tank.

The food waste dried in the second drying chamber 50 to about 55 to 65% is supplied to the third drying chamber 51. The third drying chamber 51 includes a rotating shaft 63 in the center, a stainless steel net is used for the cylindrical drum 64, and a net drum 66 provided with a spiral scraper 65 on the inner side. A superheated steam jet nozzle (not shown) for spraying high temperature superheated steam at 105 to 500 ° C. from inside and outside of the drum 64, a whole casing 67, and a casing 67 attached to the casing 67. Bearings 68 and 69 that support the rotating shaft 63 and a motor 70 that rotates the net drum 66 are provided. In the third drying chamber 51, the food waste conveying means has a scraper 65 provided on the net drum 66 and driven to rotate.

In the third drying chamber 51, high-temperature superheated steam is directly blown onto the food waste, so that the food waste discharged from the discharge port 71 has a moisture content of 10 to 20%. The superheated steam supply source 52 that generates the superheated steam supplied to the third drying chamber 51 includes a soft water device 71a and a superheated steam generator 72. A drug injection device 73 capable of supplying an additive such as an agent and a nutrient.

The present invention is not limited to the above embodiment, and for example, a plurality of rooms may be provided for any one or more of the first, second, and third drying chambers. In addition, an appropriate seal (for example, a curtain, an opening / closing member, a covering member) can be disposed in the opening of each drying chamber through which the screen conveyor 15 passes so as not to lower the internal drying efficiency.
Furthermore, when using some of the components of the food waste drying apparatus 48 according to the second embodiment as a part of the food waste drying apparatus 10 of the first embodiment, the second embodiment The present invention is also applied to the case where some of the components of the food waste drying apparatus 10 according to the first embodiment are used as part of the food waste drying apparatus 48.
Further, in the above embodiment, the description has been made using specific numerical values, but the present invention is not limited to these numerical values.

It is explanatory drawing of the drying apparatus of the food waste which concerns on the 1st Embodiment of this invention. It is explanatory drawing of the drying apparatus of the food waste which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

10: Food waste drying device, 11: First drying chamber, 12: Second drying chamber, 13: Third drying chamber, 14: Food waste, 15: Screen conveyor, 16: Superheated steam supply source, 17 : Driving roller, 18: driven roller, 19: endless screen, 20, 21: superheated steam jet nozzle, 22: exhaust duct, 24: steam generator, 25: steam heater, 26: steam pipe heater, 26a: bypass line 26b: flow rate adjusting valve, 27: fan, 28: blower, 29: air volume adjusting valve, 30, 31: steam ejection nozzle, 32: blower, 33, 34: flow rate adjusting valve, 35: hopper, 36: rotary valve, 37: loading port, 38: water receiver, 40: bypass line, 41: valve (valve), 45: conveyor, 48: drying device for food waste, 49: first drying chamber, 50: second drying chamber, 5 : Third drying chamber, 52: superheated steam supply source, 53: dust collector, 54: steam heater, 55: condenser, 56: raw material inlet, 57: screw conveyor, 58: exhaust outlet, 60: screw conveyor, 61: Cooling tower, 62: water storage tank, 63: rotating shaft, 64: drum, 65: scraper, 66: net drum, 67: casing, 68, 69: bearing, 70: motor, 71: outlet, 71a: soft water device, 72: Superheated steam generator, 73: Drug injection device

Claims (5)

A method for drying food waste discharged from homes or businesses,
A first step of drying the food waste with high temperature steam, a second step of drying the food waste dried in the first step with hot air using high temperature steam as a heat source, and a food waste dried in the second step A third step of drying with superheated steam of 105 ° C. or more and 500 ° C. or less, and the high-temperature steam used in the first step and the hot air used in the second step. A method for drying food waste, characterized by being a heat source. A device for drying food waste discharged from a home or company having first to third drying chambers through which food waste passes by a transport means,
A superheated steam supply source for supplying high-temperature superheated steam of 105 ° C or higher and 500 ° C or lower;
In the third drying chamber, a superheated steam ejection nozzle that ejects high-temperature superheated steam from the superheated steam supply source and sprays the food waste in the third drying chamber;
Air blown in the second drying chamber for blowing hot air heated by a heater that heats air using the high-temperature steam discharged from the third drying chamber as a heat source to the food waste in the second drying chamber Means,
A food waste drying apparatus having a steam ejection nozzle in the first drying chamber for spraying high temperature steam discharged from the third drying chamber onto the food waste in the first drying chamber. . 3. The food waste drying apparatus according to claim 2, wherein the superheated steam jet nozzle in the third drying chamber blows superheated steam from above and below the food waste that is gradually transported by the transport means. Food waste drying equipment. The food waste drying apparatus according to any one of claims 2 and 3, wherein the steam ejection nozzle in the first drying chamber emits high-temperature steam from above and below the food waste placed on the transport means. A device for drying food waste, characterized by spraying. The food waste drying apparatus according to any one of claims 2 to 4, wherein the conveying means passes through at least two of the first to third drying chambers. Drying equipment.

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