JP3048321B2 - Recycling plant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recycling plant, and more particularly, to a recycling plant in which a recycling dryer and a virgin dryer are arranged in parallel.

[0002]

2. Description of the Related Art Conventionally, a so-called recycling plant has been used in order to effectively use asphalt-paved road waste generated by road construction and the like. This recycling plant uses aggregate particles with asphalt coating on the surface of aggregates by mechanically crushing asphalt pavement waste excavated by remodeling or road construction by crushers or thermal cracking with hot water or high-temperature steam. These waste materials can be reused by heating and drying them with a recycle dryer.

[0003] The recycle dryer rotatably supports a cylindrical drum inclined toward the outlet side, and a steel plate scraping blade is provided on the inner peripheral wall of the drum, whereby the waste material charged into the recycle dryer is provided. Is rolled down while being scraped up, and is brought into contact with hot air supplied from a burner during that time, whereby the aggregate is heated to a predetermined temperature to regenerate the waste material.

At the time of heating in the recycle dryer, the waste material is crushed and dust is generated from the waste material. Therefore, a cyclone dust collector is used for primary dust collection. A bag filter device is used to collect a large amount of dust by the cyclone dust collector and to capture small dust mixed with a gas that cannot be collected by the cyclone dust collector.

The basic structure of this bag filter device is as follows:
A large number of cloth filter materials called bag filters are suspended in a closed container. By connecting the inside of the bag filter device and the dryer and setting the inside of the bag filter device to a pressure lower than the outside of the bag filter device, gas containing dust is sucked in from the outside of the bag filter device. As a result, fine dust in the gas is collected on the outer surface of the bag filter, and only the purified gas is discharged to the outside.

On the other hand, in such a recycling plant, in recent years, from the viewpoint of effective utilization of facilities, a virgin dryer for heating a virgin material, that is, a new material, has been provided in parallel with a recycling dryer, and both of these dryers have a single bug. One connected to a filter device has been developed. With such a structure, one bag filter device can be shared by both the recycle dryer and the virgin dryer, and the equipment cost can be greatly reduced.

FIG. 5 is a block diagram of such a recycling plant. Reference numeral 50 denotes a recycle dryer, and 51 denotes a virgin dryer. These dryers 50 and 51 have cyclone dust collectors 52 and 53 and opening / closing dampers 54 and 55, respectively. Is provided. Control devices 56 and 57 for controlling the opening degrees of the opening and closing dampers 54 and 55 in accordance with the internal pressures of the recycle dryer 50 and the virgin dryer 51 are provided.

Reference numeral 58 denotes a bag filter device as a secondary dust collector, which is connected to dryers 50 and 51 provided in parallel. 59 is a bag filter device 5
Reference numeral 60 denotes a blower fan for adjusting a displacement from the main damper 8.

In this recycling plant, when both the recycle dryer 50 and the virgin dryer 51 are operated, the opening / closing dampers 54 are respectively set so that the internal pressure of the recycle dryer 50 and the virgin dryer 51 become a predetermined set value. , 55 are controlled, and the main damper 59 is fully opened when the blower fan 60 is started to reduce the negative pressure at the start.

[0010]

However, when only the recycle dryer 50 or the virgin dryer 51 is operated, the blower fan 60 has a capability of sucking the gas amount when both the dryers 50 and 51 are operated. And the main damper 59 is fixed at a predetermined opening, so that the inside of the case of the bag filter device 58 is in an extremely negative pressure state, and the case is deformed or the filter cloth is damaged. May be.

Therefore, the problem to be solved by the present invention is that in a recycling plant in which a recycle dryer and a virgin dryer are arranged in parallel, when one of them is stopped and only one of the dryers is operated, damage to a bag filter or the like is effectively reduced. To find a way to prevent it.

[0012]

In order to solve the above-mentioned problems, the present invention provides a recycle dryer and a virgin dryer arranged in parallel, a bag filter device connected to both dryers, and a bag filter device . in recycling plant equipped with a suction fan which is connected downstream, to detect the internal pressure of the bag filter apparatus, the bug the internal pressure of the bag filter apparatus based on the results
It is characterized by having a control system for automatically adjusting by adjusting the displacement to the downstream side of the filter device .

Here, the control system includes a differential pressure sensor for measuring the internal pressure of the bag filter device, a damper device connected to the outlet of the bag filter device, and a control device based on the measurement result of the differential pressure sensor. It can be constituted by a controller that opens and closes the damper device, or by a controller that controls the number of revolutions of the suction fan based on the measurement result of the small differential pressure sensor.

[0014]

[Function] By providing a control system for automatically adjusting the internal pressure of the bag filter device, the inside of the bag filter device can be maintained at an appropriate air pressure state even though it is a large-capacity blower fan, and the suction which causes damage is provided. Can be effectively prevented.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The features of the present invention will be specifically described below based on embodiments. FIG. 1 is an overall view of a recycling plant according to one embodiment of the present invention, and FIG. 2 is a detailed view of a bag filter device.

Reference numeral 10 denotes a recycle dryer, and 11 denotes a virgin dryer. These dryers 10 and 11 have cyclone dust collectors 12 and 13 and opening / closing dampers 14 and 1, respectively.
5 are provided. Control devices 16 and 1 for controlling the degree of opening of the opening and closing dampers 14 and 15 in accordance with the internal pressure of the recycle dryer 10 and the virgin dryer 11.
7 are provided. The control devices 16 and 17 have fine differential pressure sensors 16a and 17a for measuring the internal pressures of the recycle dryer 10 and the virgin dryer 11, respectively, and open and close the open / close dampers 14 and 15 based on the measurement results. Control is performed so that the internal pressures of the virgin dryer 10 and the virgin dryer 11 become set values.

Reference numeral 18 denotes a bag filter device as a secondary dust collector, which is connected so as to communicate with outlets of dryers 10 and 11 provided in parallel. Reference numeral 19 denotes a main damper for adjusting the amount of exhaust air from the bag filter device 18, and reference numeral 20 denotes a suction blower fan having a capacity capable of sucking gas generated from both the recycle dryer 10 and the virgin dryer 11.

Reference numeral 21 denotes a control device for automatically adjusting the opening of the main damper 19, which is attached to the case of the bag filter device 18 and measures the internal pressure of the bag filter device 18, as shown in the detailed view of FIG. Small differential pressure sensor 21
a, and a controller 21b that opens and closes the main damper 19 so that the pressure inside the bag filter device 18 becomes a set value based on a preset program based on the measurement result.

Next, a specific control method of the recycling plant will be described with reference to a flowchart shown in FIG. 3 and a diagram showing the operation of the damper shown in FIG.
In this embodiment, for convenience, the amount of gas generated from the recycle dryer 10 is set to 30 and the virgin dryer 11
60 gas generation capacity and 90
It will be described as.

The recycle dryer 10 is set to an internal pressure of -5 mmAq, the virgin dryer 11 is set to an internal pressure of -5 mmAq, and the bag filter device 18 is set to an internal pressure of -150 mmAq. First, when starting the operation of the plant, the blower fan 20 is started. To start the blower fan 20, the amount of air entering the blower fan 20 is reduced as much as possible, and the main damper 19 is closed to reduce the starting current. At this point, pressure is not yet controlled.

When the fan 20 rises to the rated speed,
The operation enters the pressure control inside the bag filter device 18. When the main damper 19 starts operating so that the internal pressure of the bag filter device 18 becomes a set value, the virgin dryer 11
Then, the preparation for ignition of the recycle dryer 10 is started. When the burner is ignited, a large amount of exhaust gas is generated instantaneously, so it is necessary to open the dampers 14, 15, and 19. Therefore, first, the internal pressure is set to -150 mmAq,
The degree of opening of the dampers 14, 15, 19 is controlled. When the predetermined pressure is reached, the virgin dryer 11 and the recycle dryer 10 are ignited, and after a few seconds, the initial pressure is set to a predetermined value.
Return to 5 mm Aq and enter automatic control.

Next, when the recycle dryer 10 is stopped, the air volume decreases by 30. Therefore, the internal pressure of the bag filter device 18 is reduced by the same control as described above. Therefore, the bag filter device 18 automatically switches the main damper 1 based on the measurement result of the differential pressure sensor 21a.
9 is closed to increase the pressure. Thereby, at the same time as the internal pressure of the bag filter apparatus 18 to set pressure -150MmAq, boosts the internal pressure of the virgin dryer 11, becomes -10 to-8m m Aq, virgin dryer 1
The first damper 15 performs a closing operation. In this way, even if the overall air volume balance changes, the dampers 14, 1 are automatically set.
5, 19 can be automatically controlled and maintained at a predetermined pressure.

As described above, in the recycle dryer of the present embodiment, even when both or one of the recycle dryer 10 and the virgin dryer 11 is operated, the internal pressure of the bag filter device 18 is always kept at an appropriate level. Thus, it is possible to reliably prevent deformation of the air tube of the bag filter container due to excessive suction.

In the above embodiment, the opening / closing degree of the main damper is adjusted as a control system for controlling the internal pressure of the bag filter device. However, the present invention is not limited to this, and controls the rotation speed of the blower fan. A control system may be used. In this case, although the control speed is somewhat slower than that for opening and closing the damper, only the necessary minimum number of rotations needs to be given to the fan, so that the power running cost can be reduced.

Further, a damper for introducing outside air for keeping the internal pressure of the bag filter constant may be provided, and the damper may be controlled.

[0026]

According to the present invention, the following effects can be obtained.

(A) By providing a control system for detecting the internal pressure of the bag filter device and automatically adjusting the internal pressure of the bag filter device based on the result, any one of the recycle dryer and the virgin dryer arranged in parallel is provided. Even when the dryer is stopped, the internal pressure of the bag filter device can always be kept at an appropriate level, thereby reliably preventing the deformation of the bag filter container and the wind tube due to excessive suction, which has conventionally occurred. Can be. Further, unnecessary pressure is not applied to the filter inside the bag filter, and the life of the filter is extended.

(B) By controlling the internal pressure by opening and closing the main damper, the apparatus becomes particularly simple and the equipment can be manufactured at a relatively low cost.

(C) By adjusting the internal pressure control by the rotation speed of the blower fan, it is only necessary to give the fan the minimum rotation speed necessary, so that power is saved and energy is saved.

[Brief description of the drawings]

FIG. 1 is an overall view of a recycling plant according to an embodiment of the present invention.

FIG. 2 is a detailed view of a bag filter device.

FIG. 3 is a flowchart showing an example of control, and FIG.
Shows a control system of a virgin dryer and a recycle dryer, and (b) shows a control system of a bag filter.

4A and 4B are diagrams showing the movement of a damper during operation, wherein FIG. 4A shows a case where both a virgin dryer and a recycle dryer are operated, and FIG. 4B shows a case where only a virgin dryer is operated.

FIG. 5 is an overall view of a conventional recycling plant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Recycle dryer 11 Virgin dryer 12, 13 Cyclone dust collector 14, 15 Damper 16, 17 Control device 18 Bag filter device 19 Main damper 20 Ventilation fan 21 Control device 21a Micro pressure sensor 21b Controller

Claims (1)

(57) [Claims] 1. A recycling plant comprising a recycle dryer and a virgin dryer arranged in parallel, a bag filter device connected to both dryers, and a suction fan connected downstream of the bag filter device. detects the internal pressure of the bag filter apparatus, the server and the internal pressure of the bag filter apparatus based on the results
A recycling plant comprising a control system for automatically adjusting the amount of exhaust gas to the downstream side of a filter device .