JP3606978B2 - Waste drying method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for efficiently drying solid waste such as municipal waste and industrial waste, and more specifically, plastics which are low melting point substances are selectively removed in a pre-drying process, and the plastics are removed. The present invention relates to a drying method and apparatus for drying wastes.
[0002]
[Prior art]
Conventionally, rotary dryers used for drying sludge and the like with high water content have been used for drying solid waste. In the case of waste containing miscellaneous substances, the high temperature gas (hot air) of 400 to 600 ° C from the hot air generator melts the plastics, which are low melting point materials in the waste, and lifters (lift plates) inside the rotary dryer. ) And hinders the smooth flow of the workpiece. In the worst case, the accumulated object to be processed becomes high temperature and ignites. Therefore, it is necessary to set the temperature of the high temperature gas low or to remove the lifter.
[0003]
Further, conventionally, a method is known in which solid waste is crushed, dried and molded to convert the waste into a solid fuel to be used as a refuse-converted fuel (RDF) (for example, April 1995). (See page 38 to page 42 of Environmental Plan VOL.6 No.1 issued by the Environmental Planning Center). In this case, the same problem as described above occurs when the crushed waste is dried.
[0004]
[Problems to be solved by the invention]
In order to prevent fusion of molten plastics in the rotary dryer, if the gas temperature of the heating source is set low, the gas flow rate must be increased by that amount in order to obtain a predetermined amount of drying heat. Further, when the lifter is removed, the contact effect between the object to be dried and the high temperature gas in the rotary dryer is reduced. Therefore, in any method, it is necessary to increase the shape of the rotary dryer body.
[0005]
The present invention has been made in view of the above-mentioned points, and the object of the present invention is to sort and attach plastics by a sorter such as a model that incorporates a wind sorting mechanism in a vibrating screen in the pre-process of drying waste. If the moisture content is low, the rotary dryer is bypassed and transported to the next process.If the moisture content is high, the rotary dryer can be made compact by supplying it to the low-temperature area in the rotary dryer by air transportation and drying it. An object of the present invention is to provide a waste drying method and apparatus.
Another object of the present invention is to provide a waste drying method and apparatus suitable for use in a drying system for crushing, drying and shaping solid waste to convert the waste into solid fuel (RDF). Is to provide.
[0006]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the waste drying method of the present invention is a method of throwing waste into a rotary dryer and blowing a high-temperature gas from a hot air generator to dry the waste. As a pre-process of the drying process in the rotary dryer, the plastics contained in the waste are sorted and removed in advance, and the waste from which the plastics are removed is supplied to the rotary dryer.
In the above method, the plastics that have been sorted and removed in advance are supplied to the low-temperature part in the rotary dryer, the plastics that have been sorted and removed in advance are bypassed to the rotary dryer, or the plastics are sorted in advance. Measure the moisture content of the removed plastic. If the moisture content is above the set value, supply the plastic to the low temperature part of the rotary dryer. If the moisture content is less than the set value, rotate the plastic Bypass the rotary dryer without supplying it to the dryer.
[0007]
Moreover, it is preferable to apply each of the above methods to the drying treatment of the crushed waste in the method of crushing, drying, and shaping the waste to convert the waste into a solid fuel.
[0008]
The waste drying apparatus according to the present invention includes a rotating cylinder, an inlet hood provided at one end of the rotating cylinder, a hopper provided at the other end of the rotating cylinder, and a waste inlet provided in the rotating cylinder. A rotary dryer comprising a hot air inlet provided in the inlet hood, an exhaust gas outlet provided in the upper part of the hopper, and a dry waste discharge port provided in the lower part of the hopper,
A waste feeder connected to the waste input port;
A hot air generating furnace connected to the hot air inlet;
A wind power sorter connected to the waste supply machine for sorting plastics in the waste by wind power;
A cyclone connected to this wind power sorter via a plastic airflow conveying pipe;
Plastics extraction line and bypass line connected to this cyclone,
A plastic airflow conveying pipe connected to the plastics extraction line for supplying plastics to the low temperature part of the rotary dryer;
It is characterized by consisting of.
[0009]
In the above apparatus, a hopper is connected between the cyclone and the plastics extraction line, and a moisture meter is provided in the hopper. By the value of the moisture meter, bypassing with the plastics that carry airflow to the low temperature part of the rotary dryer. It is preferable that the switching means for switching between plastics is provided at a branch portion between the plastics extraction line from the hopper and the bypass line.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an example of the waste drying apparatus of the present invention. Reference numeral 10 denotes a rotary dryer. The rotary dryer 10 includes a rotary cylinder 12, an inlet hood 14 provided at one end of the rotary cylinder 12, a hopper 16 provided at the other end of the rotary cylinder 12, and the rotary cylinder 12. A waste inlet 18 provided in the hood 16, a hot air inlet 20 provided in the inlet hood 14, an exhaust gas outlet 22 provided in the upper part of the hopper 16, and a dry waste outlet 24 provided in the lower part of the hopper 16. It has become. A lifter (lifting plate) 26 is provided on the inner surface of the rotating cylinder 12 for lifting the waste and bringing it into contact with hot air.
[0011]
A waste supply machine 28 is connected to the waste inlet 18 through the inlet hood 14. The waste feeder 28 includes a waste hopper 30 and a waste transporter 32 connected to the lower portion of the waste hopper 30. Reference numeral 34 denotes a motor with a reduction gear. A hot air generating furnace 36 is connected to the hot air inlet 20. Reference numeral 38 denotes a blower.
The waste hopper 30 of the waste supply machine 28 is connected to a wind power sorter 40 for sorting and removing plastics in the waste by wind power. As an example, this wind power sorter 40 is configured so that plastics that are lighter than other wastes classified on the sieve of the vibrating screen 42 can be transported by wind from the air from the blower 44. Of course, exhaust gas or the like can be used instead of air.
[0012]
A cyclone 48 is connected to the wind power sorter 40 through a plastic airflow conveying pipe 46, a plastics hopper 50 is connected to the cyclone 48, and a moisture meter (for example, an infrared type) 52 is provided in the plastics hopper 50. The plastics hopper 50 is connected with a plastics extraction line 54 and a bypass line 56, and the plastics extraction line 54 is connected with a plastics airflow conveying pipe 58 for supplying the plastics to the low temperature part of the rotary dryer 10. ing. 60 is a blower for supplying air or exhaust gas, and 61 is an induction fan.
[0013]
Further, a switching means 62 for switching between the plastics that are air-flowed to the low temperature part of the rotary dryer 10 and the bypassed plastics according to the measured value of the moisture meter 52 is provided with a plastics extraction line 54 from the plastics hopper 50 and a bypass. It is provided at a branch portion with the line 56.
If the line is not switched depending on the measurement value of the moisture meter, the plastics hopper 50 can be omitted and the plastics extraction line 54 and the bypass line 56 can be connected to the cyclone 48.
[0014]
In the apparatus configured as described above, solid waste is introduced into a sorting machine 40 having a structure in which a wind sorting mechanism is incorporated in a vibrating screen 42 to sort plastics. That is, the air from the blower 44 is used to wind-transport the bulky, lightweight, low melting point (for example, 150 to 230 ° C.) plastic on the sieve to the cyclone 48 through the plastic airflow conveying pipe 46. The dust is separated by the cyclone 48. Plastics are put into a plastics hopper 50.
The moisture content of the plastics in the hopper 50 is measured by the moisture meter 50. If the moisture content is less than a certain value, for example, less than 15%, the rotary dryer 10 is bypassed and sent to the next process by the transport conveyor 64.
When the water content is a certain value or more, for example, 15% or more, it is put on the air flow from the blower 60 and put into the low temperature part of the rotary dryer 10 at 250 ° C. or lower, specifically 250 ° C. to 150 ° C. Dry together with the waste. A hot gas (hot air) of 400 to 600 ° C. is supplied from the hot air generating furnace 36.
The melting point of plastics is 150 to 230 ° C., but when this is put into a low temperature part of 250 ° C. or less, the moisture adhering to the plastics evaporates and the temperature is lower (right side in FIG. 1). The plastics will not melt.
Further, the entire amount of the selected plastics may be supplied to the low temperature part of the rotary dryer 10, and the rotary dryer 10 may be bypassed without putting the entire amount of the selected plastics into the rotary dryer 10.
[0015]
Next, a case where the above method is incorporated into a solid waste (RDF) method for solid waste will be described with reference to FIG.
First, the waste is broken into, for example, about 100 mm by the bag breaking machine 70, iron is separated by the primary magnetic separator 72, and then the foreign matter is separated by crushing to about 30 mm by the primary crusher 74, for example. Next, the waste from which iron and foreign matter are separated is introduced into the wind power sorter 40, and the plastics are sorted and removed by the same operation as shown in FIG.
The waste from which the plastics are removed is sent to the rotary dryer 10 and dried, and the plastics sorted by the wind power sorter 40 are either the low temperature part of the rotary dryer 10 or the bypass line 56 of the rotary dryer 10, Or sent to both by moisture content value.
The waste dried by the rotary dryer 10 is sent to the secondary magnetic separator 76 to remove iron, then the aluminum is removed by the aluminum sorter 78, and further, the non-combustible matter is removed by the wind sorter 80. . The waste from the wind sorter 80 is secondarily crushed to about 20 mm, for example, by the secondary crusher 82 together with the plastics from the bypass line 56. For example, waste smaller than about 20 mm is EM bacteria or lime by the quantitative supply device 84. It shape | molds at 70-80 degreeC with the granulator 86 with additives, such as. The formed body is cooled and solidified by the cooler 88, and is sized to about 20 mm in diameter, for example, by the screen 90, and becomes a waste conversion fuel (RDF) of the product. The cooler 88 may be air-cooled or water-cooled. The small particle size material that has passed through the screen 90 is returned to the quantitative supply device 84 and reused.
[0016]
【The invention's effect】
Since this invention is comprised as mentioned above, there exist the following effects.
(1) In order to increase the drying efficiency in the rotary dryer, even if the inlet hot air temperature is high (for example, about 600 ° C.), plastics having a low melting point (for example, 150 to 230 ° C.) are separated in the previous step, and the rotary dryer is By putting it in the low temperature part (for example, the part of 250 ° C. or lower), the drying process can be performed without causing trouble due to melting of plastics. In addition, the rotary dryer body can be made compact.
(2) If the water content of the selected plastics is less than a certain value, the power of the blower for supplying to the low temperature part in the rotary dryer can be reduced when the rotary dryer is configured to be bypassed. .
(3) By incorporating the drying apparatus of the present invention into a solid fuel converting apparatus for solid waste, it is possible to efficiently produce refuse conversion fuel (RDF).
[Brief description of the drawings]
FIG. 1 is a flow sheet showing an example of an apparatus for carrying out the waste drying method of the present invention.
FIG. 2 is a process explanatory diagram showing a configuration in which the flow shown in FIG. 1 is incorporated into a solid waste solid fuel conversion (RDF) method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Rotary dryer 12 Rotating cylinder 14 Inlet hood 16 Hopper 18 Waste inlet 20 Hot air inlet 22 Exhaust gas outlet 24 Dry waste outlet 26 Lifter 28 Waste supply machine 30 Waste hopper 32 Waste transport machine 36 Hot air generating furnace 40 Wind power Sorting machine 42 Vibrating sieve 44 Blower 46 Plastic airflow transfer pipe 48 Cyclone 50 Plastic hopper 52 Moisture meter 54 Plastics extraction line 56 Bypass line 58 Plastics airflow transfer pipe 60 Blower

Claims (4)

In the method of drying waste by injecting waste into the rotary dryer and blowing high-temperature gas from the hot air generator, it is included in the waste as a pre-process of the drying treatment step in the rotary dryer Sort and remove plastics in advance, supply the waste from which plastics have been removed to a rotary dryer, measure the moisture content of the plastics that have been sorted and removed in advance, and if the moisture content exceeds the set value, It was supplied to the low temperature portion of the rotary dryer, if the moisture content is less than the set value, the drying process of the waste characterized by Rukoto bypass the rotary dryer without supplying plastics rotary dryer. A method for drying waste, wherein the waste is crushed, dried and formed to form solid fuel, and the crushed waste is treated by the method according to claim 1 . A rotating cylinder, an inlet hood provided at one end of the rotating cylinder, a hopper provided at the other end of the rotating cylinder, a waste input port provided in the rotating cylinder, and a hot air inlet provided in the inlet hood And a rotary dryer comprising an exhaust gas outlet provided at the upper part of the hopper and a dry waste outlet provided at the lower part of the hopper,
A waste feeder connected to the waste input port;
A hot air generating furnace connected to the hot air inlet;
A wind power sorter connected to the waste supply machine for sorting plastics in the waste by wind power;
A cyclone connected to this wind power sorter via a plastic airflow conveying pipe;
Plastics extraction line and bypass line connected to this cyclone,
A plastic airflow conveying pipe connected to the plastics extraction line for supplying plastics to the low temperature part of the rotary dryer;
A waste drying apparatus comprising: A hopper is connected between the cyclone and the plastics extraction line, and this hopper is equipped with a moisture meter. The value of this moisture meter switches between the plastics that carry air flow to the low temperature part of the rotary dryer and the bypassed plastics. 4. The waste drying apparatus according to claim 3 , wherein the switching means is provided at a branch portion between the plastics extraction line from the hopper and the bypass line.

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