JP2003251305A - Combustible refuse drying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably dry combustible refuse with large fluctuation of moisture to a predetermined drying degree. <P>SOLUTION: The humidity H of exhaust gas proportional to the moisture content of all of combustible refuse evaporated in a drying oven 3 is measured by a hygrometer 10 to accurately and indirectly grasp the average water content of the supplied combustible refuse. By this constitution, the supply amount of the combustible refuse is regulated corresponding to the fluctuation in the total moisture content of the combustible refuse nearer to an actual moisture content and the combustible refuse with large fluctuation of moisture can be stably dried to the predetermined drying degree. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drying device for drying combustible waste with hot air.

[0002]

2. Description of the Related Art In recent years, a technique has been developed in which combustible waste obtained from municipal waste and the like is compression-molded and utilized as a solid fuel. These combustible wastes include plastic, paper,
Wood, kitchen waste, etc. are included, and in order to efficiently compression-mold this, it is necessary to dry the combustible waste in advance and adjust the degree of drying to a predetermined range.

In order to dry such combustible waste, the combustible waste supplied from one end of the drying furnace is brought into contact with hot air supplied from the hot-air stove to evaporate its moisture, and dried to a predetermined degree of dryness. A continuous drying device is used to discharge combustible waste from the other end of the drying furnace.

Such a combustible waste dryer is disclosed in Japanese Patent Application Laid-Open No. 9-138070 and Japanese Patent Application Laid-Open No. 10-197152, in which hot air from a hot stove is dried from the same side as the combustible waste. In many cases, the exhaust gas is supplied to the exhaust gas from the same side as the combustible waste, and a part of the exhaust gas discharged from the drying furnace is returned to the hot stove to be used for circulation. Usually, the degree of drying of combustible waste is controlled by adjusting the amount of fuel used in the hot-air stove so that the exhaust gas temperature of the hot air from the drying stove approaches a certain value.

Generally, in a continuous drying device for drying various articles, hot air is supplied from the discharge end side of the material to be dried in order to control the drying finish temperature. If the hot air is supplied from the discharge end side of the combustible waste, the dried combustible waste may be ignited. Therefore, the hot air is supplied from the supply end side of the combustible waste in this way. Also, it is necessary to circulate and use a part of the hot air exhaust gas.
This is to save heat energy.

[0006]

In the above-mentioned apparatus for drying combustible waste, the fluctuation in water content of the combustible waste, which is the object to be dried, is considerably larger than that in the drying apparatus for other articles, and the drying degree of the combustible waste is set to a predetermined level. There is a problem that is difficult to adjust to the range of.

To solve this problem, Japanese Patent Laid-Open No. 8-86569
In the drying device described in Japanese Patent Laid-Open No. 9-138070 and Japanese Patent Laid-Open No. 9-138070, the moisture content and weight of combustible waste supplied to the drying furnace are measured, and the combustible content supplied from these measured moisture content and weight is measured. The total moisture content of the waste is determined, and the supply amount of the combustible waste is adjusted so that the total moisture content is constant to control the drying degree of the combustible waste. The amount of combustible waste supplied is adjusted to stabilize the operating conditions of the hot-blast stove as much as possible. Each of these publications recommends the use of a non-contact type moisture meter such as an infrared moisture meter or a microwave moisture meter for measuring the moisture content of combustible waste.

However, since the combustible waste is supplied to the drying furnace in a layered or lumped state, the non-contact moisture meter that can be put to practical use as described above contains the surface layer of the combustible waste. Only moisture content can be measured. The moisture content of combustible waste that is supplied in layers and blocks is not only different between the surface layer and the interior, but also greatly differs depending on the type of waste such as plastic, paper, wood, and garbage. The moisture content measured by the method varies greatly depending on the type of dust in the surface layer.

Therefore, the moisture content measured by such a moisture meter is far from the average moisture content of the supplied combustible waste, and the moisture content of the combustible waste obtained from the measured moisture content. The total moisture content is also inaccurate. Therefore, even if the supply amount of the combustible waste is adjusted based on the total moisture content of the combustible waste thus obtained, the combustible waste cannot be stably controlled to a predetermined degree of dryness.

By the way, regarding a sugar drying apparatus at a sugar factory, the temperature and humidity of the exhaust gas from the drying furnace are measured, the moisture saturation of the exhaust gas is calculated from this temperature and humidity, and a blower fan for sucking the exhaust gas is used. It has been proposed to control the rotation speed (Japanese Patent Laid-Open No. 61-138085).

Therefore, an object of the present invention is to stably dry combustible waste having a large water content variation to a predetermined degree of drying.

[0012]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention supplies combustible waste from a feeder and hot air from a hot air oven from the same end side of a drying oven to dry the combustible waste. A combustible waste and a hot air exhaust gas are discharged from the same other end of the drying furnace, and a part of the exhaust gas discharged from this drying furnace is returned to the hot air furnace to be circulated and used for drying. A hygrometer for detecting the humidity of the exhaust gas discharged from the drying furnace is provided, and based on the exhaust gas humidity detected by this hygrometer, a configuration is adopted in which the supply amount of combustible waste from the feeder is adjusted. did.

That is, the humidity of exhaust gas, which is proportional to the water content of all combustible waste evaporated in the drying furnace, is measured with a hygrometer,
By accurately and indirectly grasping the average moisture content of the supplied combustible waste, the supply amount is adjusted according to the fluctuation of the total moisture content of the supplied combustible waste that is closer to the actual, Combustible waste with large fluctuations in water content can be stably dried to a specified degree of drying.

A moisture meter for measuring the moisture content of the combustible waste supplied from the feeder is provided, and the supply of the combustible waste from the feeder is based on the change in the moisture content measured by the moisture meter. By correcting the amount, the combustible waste can be more stably dried to a predetermined degree of drying.

That is, since the adjustment of the combustible waste supply amount based on the exhaust gas humidity is feedback control, there is a control delay. However, since the exhaust gas humidity increases as the water content in the combustible waste evaporates, the control delay is less than the feedback control based on the exhaust gas temperature that rises after the water content in the combustible waste has sufficiently evaporated. On the other hand, since the conventional method of measuring the moisture content of the supplied combustible waste and adjusting the supply amount of the combustible waste is feedforward control, there is no control delay. As mentioned above, the practical non-contact moisture meter cannot accurately measure the average moisture content of the supplied combustible waste, but it can grasp the moisture fluctuation of the supplied combustible waste to some extent. . Therefore, by correcting the supply amount of combustible waste based on the relative increase / decrease in the moisture content measured by a moisture meter, the control delay of the feedback control is compensated, and the drying degree of combustible waste is more stable. Can be made.

The increase / decrease change in the moisture content measured by the moisture meter is smoothed at predetermined intervals, and the smoothed increase / decrease amount of the moisture content is used to correct the supply amount of the combustible waste. This smooths the instantaneous fluctuation of the moisture content due to the difference in the type of dust on the surface layer of the combustible waste measured by the moisture meter, and changes the actual moisture content of the combustible waste due to the difference in the input lot. , Which can be reflected more accurately in the correction of the supply amount of combustible waste.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, based on FIG. 1 and FIG.
An embodiment of the present invention will be described. FIG. 1 shows a first embodiment. This drying apparatus for combustible waste supplies combustible waste from the screw type feeder 1 and hot air from the burner type hot air stove 2 from the same supply end side of the rotary drum type drying furnace 3 and is transferred in the rotary drum. Meanwhile, the dried combustible waste and the exhaust gas of the hot air are discharged from the same discharge end side of the drying furnace 3, and a part of the exhaust gas is returned to the hot air furnace 2 by the blower 5 through the pipe 4 and is used for circulation. The remaining exhaust gas is sent to an exhaust gas processing device (not shown) by a blower 7 through the pipe 6 and is discharged to the outside.

On the discharge end side of the drying furnace 3, there are provided a pressure gauge 8, a thermometer 9 and a hygrometer 10 for measuring the pressure P, the temperature T and the humidity H of the discharged exhaust gas, respectively. The signal is input to the controller 11. The controller 11 also includes a motor 12 for driving the screw 1a of the feeder 1 and valves 13 for adjusting the amounts of fuel and air supplied to the burner 2a of the hot stove 2.
It is connected to a and 13b and the blower 7 which discharges exhaust gas outside.

The controller 11 is preset with respective reference values for the pressure P, temperature T, and humidity H of the exhaust gas. Each standard value is, when combustible waste with standard moisture content is supplied by the amount of the standard treatment capacity of the drying furnace 3,
Each value of the pressure P, the temperature T and the humidity H at which an appropriate degree of drying is obtained is empirically obtained.

When the pressure P detected by the pressure gauge 8 is higher than the reference value, the controller 11 increases the output of the blower 7 to increase the emission amount of exhaust gas to the outside, and the thermometer 9
When the temperature T detected at 1 is higher than the reference value, the valves 13a and 13b are throttled to reduce the combustion of the burner 2a in the hot stove 2. Also, the humidity H detected by the hygrometer 10
Is higher than the reference value, the rotation speed of the motor 12 is reduced to reduce the supply amount Q of combustible waste from the feeder 1.

In this way, by controlling the pressure P, temperature T and humidity H of the exhaust gas so as to approach the respective reference values, the drying degree of the combustible waste can be stably kept within a predetermined range. In particular, in this embodiment,
The moisture fluctuations of the combustible waste supplied are indirectly and accurately determined by the humidity H of the exhaust gas, and the supply amount Q of the combustible waste is increased / decreased. It is possible to maintain the dryness of combustible waste in a stable state without significantly changing the conditions.

FIG. 2 shows a second embodiment. The basic configuration of this combustible waste drying device is the same as that of the first embodiment, and the combustible waste is introduced into the hopper at the discharge end of the conveyor 14 that conveys the combustible waste into the hopper of the feeder 1. Infrared moisture meter 15 for measuring the moisture content W of combustible waste
Is provided, and the detection signal thereof is additionally input to the controller 11 except.

In addition to the above-mentioned reference values, the controller 11 is preset with the standard moisture content of the combustible waste supplied as a reference value, and the humidity H detected by the hygrometer 10 Increase / decrease amount ΔQ of the supply amount Q of combustible waste based on
Is corrected by the following equation based on the increase / decrease change amount ΔW of the deviation of the moisture content W from the reference value detected by the moisture meter 15. ΔQ _W = ΔQ−G · ΔW (1) where ΔQ _W is the amount of increase or decrease in the corrected supply amount Q, and G is the control gain. In addition, the increase / decrease change amount ΔW is measured by the moisture meter 15
Is an average of deviations of the measured value of the water content W from the reference value at every predetermined time, and the measured value is instantaneous due to the difference in the kind of dust of the combustible waste surface layer measured by the moisture meter. The fluctuations are smoothed and the fluctuation of the actual moisture content of the combustible waste due to the difference in the input lot is reflected in the formula (1).

[0024]

As described above, the apparatus for drying combustible waste according to the present invention measures the humidity of exhaust gas, which is proportional to the water content of all the combustible waste evaporated in the drying furnace, with a hygrometer.
Accurately and indirectly grasp the average moisture content of the supplied combustible waste, and adjust the supply of combustible waste according to the fluctuation of the actual total water content of the supplied combustible waste. Therefore, it is possible to stably dry combustible waste having a large water content variation to a predetermined degree of drying.

Further, a moisture meter for measuring the moisture content of the combustible waste supplied from the feeder is provided, and the combustible waste from the dispenser is based on the change in the moisture content measured by the moisture meter. By correcting the supply amount of the above, it is possible to compensate the feedback delay to the supply amount adjustment of the combustible waste based on the humidity of the exhaust gas, and to more stably adjust the drying degree of the combustible waste within a predetermined range.

Further, the increase / decrease change of the moisture content measured by the moisture meter is smoothed at predetermined intervals, and the smoothed increase / decrease amount of the moisture content is corrected for the supply amount of the combustible waste. By smoothing the instantaneous fluctuation of the moisture content due to the difference in the type of dust on the surface layer of combustible waste measured with a moisture meter, the moisture content of the actual combustible waste due to the difference in the input lot etc. The fluctuation can be reflected more accurately in the correction of the supply amount of combustible waste.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a combustible waste drying device according to a first embodiment.

FIG. 2 is a configuration diagram showing a combustible waste drying device according to a second embodiment.

[Explanation of symbols]

1 feeder 1a screw 2 hot stoves 2a burner 3 drying oven 4 piping 5 Blower 6 piping 7 Blower 8 pressure gauge 9 thermometer 10 Hygrometer 11 Controller 12 motors 13a, 13b valves 14 Conveyor 15 Moisture analyzer

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B09B 3/00 303M (72) Inventor Shinji Hara 1-12-19 Kitahorie Nishi-ku, Osaka-shi Kurimoto Tetsudo Co., Ltd. On-site F-term (reference) 3L113 AA06 AB03 AC04 AC45 AC46 AC53 AC54 AC68 BA01 CA08 CA09 CA10 CB03 CB22 CB24 CB34 DA11 DA24 4D004 AA03 AA07 AA12 AB01 CA42 DA01 DA02 DA08 DA12

Claims (3)

[Claims] 1. Combustible waste from a feeder and hot air from a hot air oven are supplied from the same end side of a drying oven, and dried combustible waste and exhaust gas of hot air are discharged from the same other end side of the drying oven. Then, in a device for drying combustible waste, in which a part of the exhaust gas discharged from the drying furnace is returned to the hot air stove and used for circulation, a hygrometer for measuring the humidity of the exhaust gas discharged from the drying furnace is provided. A drying apparatus for combustible waste, wherein the supply amount of combustible waste from the feeder is adjusted based on the exhaust gas humidity measured by the hygrometer. 2. A moisture meter for measuring the moisture content of combustible waste supplied from the feeder is provided, and the combustible waste from the feeder is based on the increase / decrease in the moisture content measured by the moisture meter. The combustible waste drying apparatus according to claim 1, wherein the supply amount of the combustible waste is corrected. 3. The increase / decrease change of the moisture content measured by the moisture meter is smoothed at predetermined time intervals, and the smoothed increase / decrease amount of the moisture content is corrected for the supply amount of the combustible waste. The combustible waste drying apparatus according to claim 2, which is used for.