JP2000205746A - Drying device for waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a harmful substance such as dioxin from being synthesized by providing a steam generating device which feeds steam into a dryer main body, and making the steam generated by the steam generating device react with waste which is thrown into the dryer main body. SOLUTION: Waste which is thrown into a dryer main body 4 is stirred by a rotating drum inside, and thus, a loosening effect of the waste being carried and a uniform contact with a gas stream are tried to be obtained, and an effective drying becomes possible. On the upstream side of the dryer main body 4, a steam generator 3 and a heater 8 are arranged, and steam of a pressure which is approx. equal to the atmospheric pressure is introduced into the dryer main body 4 from there. The steam generated from the steam generator 3, is overheated by the heater 8, and becomes an overheated steam of 100 deg.C or higher. By this constitution the waste can be dried without generating dioxin, and the changing refuse into a solid fuel becomes easier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste drying apparatus for drying waste.

[0002]

2. Description of the Related Art In recent years, the need for converting solid waste into solid fuel has become apparent. It has been reported that general waste in Japan has much more moisture than that in Europe and the United States, and the water content exceeds 50%. In the case of handling waste having a high water content as described above, the sorting accuracy of combustibles deteriorates as it is, or a failure occurs in the apparatus. Further, since there is a problem in the formability when solidifying waste, it is generally practiced to dry the refuse with a usual dryer to make the water content approximately 10% and then to convert it into solid fuel. .

[0003]

As a currently used drying apparatus, for example, a rotary furnace type drying apparatus as shown in FIG. 3 is widely used. In FIG. 3, D is a direct-type rotary dryer. H2 is a heating device of the drying device D, H
o is a hopper, B is a structural part of a dryer, and V is a ventilator.

[0004] In the case of the conventional drying apparatus D shown in FIG. 3, after burning fuel (kerosene, propane, etc.), high-temperature combustion gas is directly applied to waste to perform drying. However, it has recently become clear that when such combustion air-flow drying is performed, high-temperature combustion gas reacts with harmful components in waste to generate harmful substances such as dioxin. Therefore, in order to suppress the generation of dioxin, it is necessary to take measures such as suppressing the temperature of the combustion gas. However, if measures such as suppressing the temperature of the combustion gas are taken, the drying speed becomes slow. There is a problem that the throughput is reduced. Further, in order to prevent a reduction in the amount of waste disposal, it is necessary to increase the size of the drying equipment.

The present invention has been made to solve the above-mentioned problems, and is characterized in that superheated steam is used as a drying medium for drying wastes. If the temperature of water vapor is 100 degrees or more, the vapor pressure of water is 760 mmHg
Drying proceeds because of the above. Further, when the temperature of the steam is 280 ° C. or more, the drying speed is higher than the flash drying at the same flow rate, so that more efficient drying can be performed. When dried with superheated steam in this way, no harmful substances such as dioxin are synthesized because the waste does not react with steam.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a waste drying apparatus for heating and drying waste put in a dryer body, wherein a steam generator for supplying steam to the dryer body is provided. And a waste drying device for causing the steam generated by the steam generating device to act on the waste put into the dryer main body. Further, the above means 1
, A waste drying apparatus in which the temperature of steam is set to 100 ° C. or more. Further, in the above-mentioned means 1, a waste drying apparatus in which the temperature of steam is set to 280 ° C. or higher is provided. Further, the above means 1 to 3
In any of the above, a waste drying apparatus for setting the oxygen concentration in the dryer body to less than 5% is provided.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a block diagram showing the basic configuration of the present invention, and FIG. 2 is an explanatory diagram showing the configuration of the first embodiment of the present invention. The first embodiment exemplifies a case where the present invention is applied to a rotary drying device.
In FIG. 1, 1 is a waste drying device, 2 is an inlet, 3
Is a steam generator, 4 is a dryer body, and 5 is an outlet.
The superheated steam generated by the steam generator 3 is sent to the dryer body 4. Further, waste is introduced into the dryer main body 4 through the introduction port 2, and is heated by steam to evaporate water. The waste that has been dried and has a low water content is discharged from a discharge port 5 on the opposite side of the dryer main body 4. The steam required for drying and the steam evaporated from the waste are circulated again to the steam generator 3 and reheated.

In FIG. 2, parts corresponding to those in FIG. 1 are denoted by the same reference numerals. Reference numeral 6 denotes a hopper that forms the waste input port 2, and reference numeral 7 denotes an input feeder that conveys the input waste to the dryer main body 4. The dryer main body 4 is a rotating drum, and is rotated in the axial direction by a driving device (not shown). Reference numeral 8 denotes a heater for heating the steam generated by the steam generator 3 and supplies the steam to the input side of the dryer body 4. 9 is a discharge feeder arranged on the discharge side, 10 is a relief valve, and 11 is a condenser. Reference numeral 12 denotes a cyclone and reference numeral 13 denotes a blower.

In the waste drying apparatus 1 according to the first embodiment shown in FIG. 2, waste introduced from the inlet 2 is introduced into the dryer main body 4 through the introduction feeder 7. It is desirable to use a rotary valve or a screw feeder as the input feeder 7 to ensure both quantitative supply and sealing. The waste put into the dryer main body 4 is agitated by the internal rotating drum, so that the effect of loosening the transferred waste and uniform contact with the airflow can be achieved, and effective drying can be achieved. The steam generator 3 and the heater 8 are provided on the upstream side of the dryer body 4, from which steam having a pressure substantially equal to the atmospheric pressure is introduced into the dryer body 4.

[0010] The steam generator 3 comprises a heating source and a heat exchanger. The steam generated by the steam generator 3 is heated by the heater 8 to become superheated steam of 100 degrees or more. It is known that in drying with superheated steam, the temperature (reversal temperature) exceeding the drying speed in flash drying is about 280 degrees experimentally. By increasing the steam temperature above this reversing temperature, the drying speed increases, As a result, the size of the waste drying apparatus 1 can be reduced. For this reason, it is essential that the temperature of the steam is at least 100 ° C. or more, which is necessary for drying, and it is desirable that the steam is heated to a temperature of 280 ° C. or more which is a reversal temperature or more.

The waste put into the dryer main body 4 is stirred by the internal rotating drum as described above, and is dried by being superheated by superheated steam. The dried waste is discharged from an outlet 5 on the opposite side of the inlet 2 of the dryer body 4. At this time, if water vapor leaks from the outlet 5, the water cooled by the outside air condenses and adheres to the waste again as moisture. Therefore, the outlet 5 is also like a rotary valve or a screw-type feeder device. In addition, a mechanism that prevents leakage of water vapor is essential. Further, if the temperature of steam after heat exchange with the waste becomes 100 ° C. or less, water is generated by re-condensation.
It is necessary to adjust the input steam amount so that the temperature becomes higher than the degree.

The exhausted steam is returned by the heater 8 via the cyclone 12 and the blower 13, and is supplied into the dryer body 4 as superheated steam after reheating. In addition, a relief valve 10 is provided near the exhaust port 5, and discharges a vapor corresponding to an increase in pressure due to water vapor evaporated from the waste to the outside of the system. The water vapor discharged out of the system is condensed by the condenser 11 and is discharged as water.

[0013]

According to the present invention, there is provided a waste drying apparatus for heating and drying waste put in a dryer body.
A steam generator for supplying steam in the dryer body was provided, and a steam dryer for causing the steam generated by the steam generator to act on the waste put in the dryer body was configured. Further, in the above-described means 1, a waste drying apparatus in which the temperature of steam is set to 100 ° C. or higher is provided. Further, in the above-mentioned means 1, a waste drying apparatus in which the temperature of steam is set to 280 ° C. or higher is constituted. Furthermore, in any one of the above-mentioned means 1 to 3, a waste drying apparatus for setting the oxygen concentration in the dryer main body to less than 5% is configured.

By drying the waste with the apparatus according to the first embodiment of the present invention, the waste is dried in an atmosphere in which oxygen is cut off, so that abnormal combustion in the drying apparatus does not occur. Stable operation becomes possible. In addition, since harmful substances such as dioxins, which had been a problem when drying with superheated air, are not generated, the drying temperature can be increased, and as a result, the entire waste drying apparatus can be used. There is also an effect that the size can be reduced.

Therefore, according to the present invention, waste can be dried without generating dioxin, so that it becomes easy to convert garbage into solid fuel.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of the first embodiment of the present invention.

FIG. 3 is a configuration explanatory view of a conventionally known direct-coupled rotary drying apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Waste drying apparatus 2 Input port 3 Steam generator 4 Dryer main body 5 Output port 6 Hopper 7 Input feeder 8 Heater 9 Discharge feeder 10 Relief valve 11 Condenser 12 Cyclone 13 Blower

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI theme coat ゛ (reference) F26B 17/32 B09B 3/00 ZAB // F26B 17/34 303M F-term (reference) 3L113 AA06 AA07 AC05 AC16 AC45 AC46 AC48 AC49 AC51 AC58 AC60 AC63 AC68 AC77 AC90 BA01 CA08 CA12 DA07 DA10 DA14 DA19 DA26 4D004 AA46 AB01 BA03 CA22 CA42 CB09 CB31 CB44 DA03 DA06 DA10 4H015 AA01 AB01 BA09 BB04 CB01

Claims (4)

[Claims] 1. A waste drying apparatus for heating and drying waste put in a dryer body, comprising: a steam generator for supplying steam to the dryer body; A waste steam applied to the waste put into the dryer body. 2. The waste drying apparatus according to claim 1, wherein the temperature of the steam is set to 100 ° C. or higher. 3. The waste drying apparatus according to claim 1, wherein the temperature of the steam is 280 ° C. or higher. 4. The waste drying apparatus according to claim 1, wherein the oxygen concentration in the dryer body is set to less than 5%.