JP7267193B2 - Asphalt plant and method for producing asphalt mixture - Google Patents

Description

The present invention relates to an asphalt plant for producing an asphalt mixture and a method for producing an asphalt mixture.

The asphalt plant that manufactures the asphalt mixture known as road pavement consists of a new aggregate drying furnace for heating and drying the new aggregate, and a recycled aggregate drying furnace for heating and drying the recycled aggregate. A drying oven and a mixer for mixing heated virgin aggregate, recycled aggregate and asphalt to produce an asphalt mixture.

New aggregate is unused aggregate such as crushed stone and sand. On the other hand, recycled aggregate is obtained by pulverizing asphalt waste dug up by road construction or the like. Therefore, when the recycled aggregate is heated for drying, hydrocarbon-based odor components are generated from the asphalt contained in the recycled aggregate. In the conventional asphalt plant, in order to deodorize the exhaust gas generated when heating the recycled aggregate, a combustion-type deodorizing device is connected to the recycled aggregate drying furnace, and the exhaust gas generated in the recycled aggregate drying furnace is deodorized. Odor components are oxidatively decomposed by heating (see Patent Document 1, for example).

JP 2009-001996 A

The exhaust gas generated in the new aggregate drying furnace contains less odorous components than the exhaust gas generated in the recycled aggregate drying furnace. Therefore, considering the influence of the odor on the surrounding area of the asphalt plant, it is desirable to deodorize the exhaust gas generated in the new aggregate drying furnace as well. However, in order to newly add a deodorizing device for deodorizing the exhaust gas of the new aggregate drying furnace, installation space is required. In addition, the combustion type deodorizer heats the exhaust gas with a burner that uses heavy oil as fuel, which increases costs such as fuel costs and increases the emissions of greenhouse gases such as _CO2 generated from the asphalt plant. end up

The problem to be solved by the present invention is to provide an asphalt plant and a method for producing an asphalt mixture that can deodorize the exhaust gas generated in the new aggregate drying furnace without installing a new deodorizing device.

[1] The asphalt plant according to the present invention includes a new aggregate drying furnace for drying new aggregate, a recycled aggregate drying furnace for drying recycled aggregate, and the new aggregate drying furnace. An asphalt plant comprising a new aggregate, a recycled aggregate dried in a drying furnace for recycled aggregates, and a mixer for mixing asphalt, wherein exhaust gas generated in the drying furnace for new aggregates and and a deodorizing device that heats the exhaust gas generated in the drying furnace for recycled aggregates to oxidatively decompose odorous components.

[2] In the above invention, the deodorizing device comprises a combustion chamber having a first burner and two or more heat storage chambers respectively communicating with the combustion chamber, and the drying furnace for new aggregates and the regeneration Exhaust gas from an aggregate drying furnace is supplied to one of the heat storage chambers for preheating, and the preheated exhaust gas is heated by the first burner in the combustion chamber to oxidatively decompose the odorous components. It may also be a regenerative combustion type deodorizing device in which heat is recovered from the discharged exhaust gas in another regenerative chamber and then discharged.

[3] In the above invention, a first exhaust fan for sending exhaust gas generated in the new aggregate drying furnace to the deodorizing device, and a second exhaust fan for sending exhaust gas generated in the recycled aggregate drying furnace to the deodorizing device. and a third exhaust fan for sending the exhaust gas deodorized by the deodorizing device to the exhaust port.

[4] In the above invention, a flue may be provided in which the exhaust gas generated in the drying furnace for new aggregates and the exhaust gas generated in the drying furnace for recycled aggregates are collected and supplied to the deodorizing device. .

[5] In the above invention, the flue includes a first flue connected to the new aggregate drying furnace, a second flue connected to the recycled aggregate drying furnace, and a third flue in which the first flue and the second flue are assembled, and the first exhaust fan is installed in the first flue and the Two exhaust fans may be installed in the second flue and the third exhaust fan may be installed in the third flue.

[6] In the above invention, first internal pressure measuring means for measuring the internal pressure of the drying furnace for new aggregates, second internal pressure measuring means for measuring the internal pressure of the drying furnace for recycled aggregates, and the deodorizing device. a third internal pressure measuring means for measuring the internal pressure of the first exhaust fan, the second exhaust fan, and a control means for controlling the third exhaust fan; The control means controls the exhaust air volume of the first exhaust fan based on the measurement result of the first internal pressure measurement means, and controls the exhaust air volume of the second exhaust fan based on the measurement result of the second internal pressure measurement means. The exhaust air volume of the fan may be controlled, and the exhaust air volume of the third exhaust fan may be controlled based on the measurement result of the third internal pressure measuring means.

[7] In the above invention, first internal pressure measuring means for measuring the internal pressure of the drying furnace for new aggregates, second internal pressure measuring means for measuring the internal pressure of the drying furnace for recycled aggregates, and the first and control means for controlling the exhaust fan, the second exhaust fan, and the third exhaust fan, and the control means controls the measurement result of the first internal pressure measurement means. controls the amount of exhaust air from the first exhaust fan, controls the amount of exhaust air from the second exhaust fan based on the measurement result of the second internal pressure measuring means, and controls the amount of exhaust air from the first exhaust fan. The exhaust air volume of the third exhaust fan may be controlled based on the air volume and the exhaust air volume of the second exhaust fan.

[8] In the above invention, the drying furnace for recycled aggregate has a cylindrical shape that is supported so as to be rotatable around an inclined axis, and causes the stored recycled aggregate to flow along the inclination while being stirred. an aggregate supplying means for supplying recycled aggregates into the rotating drum from one end of the rotating drum located at a higher position among both ends of the rotating drum; and the other end of the rotating drum into the rotating drum. and a second burner that emits a flame to heat the recycled aggregate.

[9] In the above invention, the drying furnace for recycled aggregate may include a cylindrical member that surrounds the flame of the second burner in the rotating drum.

[10] The method for producing an asphalt mixture according to the present invention includes a first step of drying new aggregate in a drying furnace for new aggregates, and a second step of drying recycled aggregates in a drying furnace for recycled aggregates. and a third step of mixing the new aggregate dried in the first step, the recycled aggregate dried in the second step, and asphalt with a mixer. The method includes a fourth step of heating the exhaust gas generated in the first step and the exhaust gas generated in the second step with a deodorizing device to oxidatively decompose malodorous components.

[11] In the above invention, the fourth step includes, as the deodorizing device, a combustion chamber having a first burner and two or more heat storage chambers respectively communicating with the combustion chamber, and Exhaust gas from the drying furnace for wood and the drying furnace for recycled aggregates is supplied to one of the heat storage chambers for preheating, and the preheated exhaust gas is heated in the combustion chamber by the first burner to oxidatively decompose odorous components. However, it may include using a regenerative combustion type deodorizing device that recovers heat from the exhaust gas in which the malodorous components are oxidatively decomposed in the other regenerative chamber and then discharges the deodorizing device.

[12] In the above invention, the fifth step of measuring the internal pressure of the new aggregate drying furnace, the sixth step of measuring the internal pressure of the recycled aggregate drying furnace, and the measuring of the internal pressure of the deodorizing device. and an eighth step of controlling, based on the measurement result of the fifth step, the exhaust air volume of a first exhaust fan that sends out the exhaust gas generated in the first step to the deodorizing device. a ninth step of controlling, based on the measurement result of the sixth step, the exhaust air volume of a second exhaust fan for sending the exhaust gas generated in the second step to the deodorizing device; and the seventh step. and a tenth step of controlling the exhaust air volume of a third exhaust fan that sends out the exhaust gas deodorized in the fourth step to the exhaust port based on the measurement result of the above.

[13] In the above invention, an eleventh step of measuring the internal pressure of the new aggregate drying furnace;
A twelfth step of measuring the internal pressure of the drying furnace for recycled aggregate, and a first exhaust fan for sending the exhaust gas generated in the first step to the deodorizing device based on the measurement result of the eleventh step. a thirteenth step of controlling the amount of exhaust air; and based on the measurement result of the twelfth step, controlling the amount of exhaust air of a second exhaust fan that sends out the exhaust gas generated in the second step to the deodorizing device. A third exhaust fan that sends the exhaust gas deodorized in the fourth step to an exhaust port based on the fourteenth step, the exhaust air volume of the first exhaust fan, and the exhaust air volume of the second exhaust fan. and a fifteenth step of controlling the amount of exhaust air.

[14] In the above invention, the drying furnace for recycled aggregate has a cylindrical shape that is supported so as to be rotatable around an inclined axis, and causes the stored recycled aggregate to flow along the inclination while being stirred. and the second step includes supplying recycled aggregates into the rotating drum from one of the ends of the rotating drum at a higher position, and supplying the recycled aggregate into the rotating drum from the other end of the rotating drum radiating a flame from a second burner into said rotating drum to heat the recycled aggregate.

According to the present invention, the exhaust gas generated in the drying furnace for new aggregate and the exhaust gas generated in the drying furnace for recycled aggregate are supplied to one deodorizing device for deodorizing. Exhaust gas generated in the new aggregate drying furnace can be deodorized without

FIG. 1 is a schematic diagram showing the configuration of an asphalt plant according to a first embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration of the mixing line of the asphalt plant according to FIG. FIG. 3 is a block diagram showing a control device for controlling the amount of exhaust air from the first, second and third exhaust fans shown in FIG. FIG. 4 is a graph showing an example of the relationship between the amount of exhaust air controlled by the control device shown in FIG. 3 and the internal pressure. FIG. 5 is a cross-sectional view showing various zones generated within the rotating drum of the recycled aggregate drying furnace shown in FIG. FIG. 6 is a cross-sectional view showing another example of the recycled aggregate drying oven shown in FIG. FIG. 7 is a schematic diagram showing the configuration of the regenerative combustion type deodorizing apparatus shown in FIG. 8(A) to 8(C) are explanatory diagrams showing the operation cycle of the regenerative combustion deodorizing apparatus shown in FIG. FIG. 9 is a flow chart showing the procedure for producing an asphalt mixture in the asphalt plant shown in FIGS. 1 and 2. FIG. FIG. 10 is a block diagram showing a control device according to the second embodiment of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.
<<1st Embodiment>>
1 and 2 are schematic diagrams showing the configuration of an asphalt plant 1 in which an asphalt plant and an asphalt mixture manufacturing method according to the present invention are implemented. The asphalt plant 1 of this embodiment includes a new aggregate drying line 3 that heats and dries the new aggregate 2, a recycled aggregate drying line 5 that heats and dries the recycled aggregate 4, and mixes the aggregate and asphalt. and a mixing line 6.

The new aggregate 2 is crushed stone, sand, or the like obtained by crushing and classifying rocks or the like with a crusher. The recycled aggregate 4 is obtained by pulverizing asphalt waste dug up by road construction or the like. The asphalt plant 1 produces three types of asphalt mixtures: an asphalt mixture using only the new aggregate 2, an asphalt mixture using only the recycled aggregate 4, and an asphalt mixture using the new aggregate 2 and the recycled aggregate 4. be able to. Further, when producing an asphalt mixture using new aggregate 2 and recycled aggregate 4, the asphalt plant 1 can mix the new aggregate 2 and the recycled aggregate 4 at an arbitrary ratio.

The new aggregate drying line 3 includes a hopper 31, a new aggregate drying furnace 32, a first flue 33, a primary dust collector 34, a secondary dust collector 35, and a first exhaust fan 36. ing. The hopper 31 is a quadrangular pyramid-shaped box with a narrowed bottom, and temporarily stores the new aggregate 2 supplied from the top by the heavy machinery, and the stored new aggregate 2 is discharged from the supply port provided at the bottom. It is supplied to the belt conveyor 311 . The belt conveyor 311 supplies the new aggregate 2 to the new aggregate drying oven 32 .

The new aggregate drying furnace 32 is a drying furnace in which the new aggregate 2 is made to flow while being stirred, while the new aggregate 2 is heated and dried. More specifically, the new aggregate drying furnace 32 is a direct fire countercurrent type drying furnace in which the flame of a burner is radiated from the direction opposite to the flow direction of the new aggregate 2 (opposite direction) for heating. Furnace. The new aggregate drying furnace 32 includes a rotating drum 321 , a cold hopper 322 , a hot hopper 323 and a drying burner 324 .

The rotating drum 321 has a cylindrical shape so as to accommodate the new aggregate 2, and has a large number of raking blades (not shown) on its inner surface. The rotating drum 321 is arranged such that its axis is slightly inclined with respect to the horizontal. In the example shown in FIG. 1, the rotary drum 321 is inclined such that the right end is higher than the left end. A cold hopper 322 is installed at one end of the rotating drum 321 at a high position, and a hot hopper 323 is arranged at the other end at a low position.

The cold hopper 322 receives the new aggregate 2 supplied by the belt conveyor 311 from an inlet (not shown) and supplies it to the rotating drum 321 . The rotating drum 321 rotates around the inclined axis to agitate the new aggregates 2 with the raking blades and flow them toward the hot hopper 323 along the inclination. A drying burner 324 is installed in the hot hopper 323 . The drying burner 324 heats and dries the new aggregates 2 by radiating flame into the rotating drum 321 from a direction opposite to the flow direction of the new aggregates 2 . The hot hopper 323 discharges the dried new aggregate 2 from a discharge port (not shown). The discharged new aggregates 2 are transported by a trolley device, a hot elevator, or the like, and stored in a hot bin equipped with a heat retaining function, though not shown in detail.

The cold hopper 322 is connected to a first flue 33 for exhausting the exhaust gas generated by heating the new aggregate 2 from the new aggregate drying furnace 32 . Unlike the recycled aggregate 4, the new aggregate 2 does not contain waste asphalt. Therefore, the exhaust gas generated by heating the new aggregate 2 contains almost no combustible oil, but contains a large amount of dust.

The primary dust collector 34, the secondary dust collector 35, and the first exhaust fan 36 are connected to the first flue 33 in this order. The primary dust collector 34 is a dust collector that removes relatively large dust particles from the exhaust gas. As the primary dust collector 34, for example, an inertia dust collector is used that changes the direction of the exhaust gas in the device and separates dust from the exhaust gas by inertial force. The secondary dust collector 35 is a dust collector that removes relatively fine dust that has not been removed by the primary dust collector 34 from the exhaust gas. As the secondary dust collector 35, for example, a bag filter dust collector is used in which a large number of bag-shaped filters made of cloth or non-woven fabric are installed, and the exhaust gas containing dust is filtered through the filters. The first exhaust fan 36 sucks exhaust gas from the new aggregate drying furnace 32 through the primary dust collector 34 and the secondary dust collector 35 . As the first exhaust fan 36, an exhaust fan is used in which the amount of exhaust air can be adjusted by inverter-controlling a drive motor.

The recycled aggregate drying line 5 includes a hopper 51 , a recycled aggregate drying furnace 52 , a second flue 53 , a primary dust collector 54 , and a second exhaust fan 55 . The hopper 51 is substantially the same as the hopper 31 of the new aggregate drying line 3, temporarily stores the recycled aggregate 4 supplied from the top by the heavy machinery, and is provided at the bottom with the stored recycled aggregate 4. It is supplied to the belt conveyor 511 from the supply port. The belt conveyor 511 supplies the recycled aggregate 4 to the recycled aggregate drying furnace 52 .

The recycled aggregate drying furnace 52 is a drying furnace in which the recycled aggregate 4 is agitated and flowed, while the recycled aggregate 4 is heated and dried. More specifically, the recycled aggregate drying furnace 52 is a direct fire countercurrent type drying furnace in which heat is applied by radiating burner flames from a direction opposite to the flow direction of the recycled aggregate 4 (opposite direction). Furnace. The recycled aggregate drying furnace 52 includes a rotating drum 521 , a cold hopper 522 , a hot hopper 523 , a drying burner 524 and a bucket 525 .

The rotating drum 521 has a cylindrical shape so as to accommodate the recycled aggregate 4, and is provided with a large number of raking blades 521a (see FIG. 5) on its inner surface. The rotating drum 521 is arranged such that its axis is slightly inclined with respect to the horizontal axis. In the example shown in FIG. 1, the rotary drum 521 is inclined such that the left end is higher than the right end. A cold hopper 522 is installed at one end of the rotary drum 521 at a higher position, and a hot hopper 523 is arranged at the other end at a lower position.

The cold hopper 522 corresponds to an example of the aggregate supply means of the present invention, and receives the recycled aggregate 4 supplied by the belt conveyor 511 from an inlet 522a (see FIG. 5) and supplies it to the rotating drum 521. The rotating drum 521 rotates around the inclined axis to agitate the recycled aggregates 4 with the raking blades 521a and flow them toward the hot hopper 523 along the inclination. A drying burner 524 corresponding to an example of the second burner of the present invention is installed in the hot hopper 523 . The drying burner 524 heats and dries the recycled aggregate 4 by radiating flame into the rotating drum 521 from a direction opposite to the flow direction of the recycled aggregate 4 .

Below the hot hopper 523, a bucket 525 for receiving recycled aggregates 4 discharged from a discharge port 523a (see FIG. 5) provided at the bottom of the hot hopper 523 is arranged. The bucket 525 stores a predetermined amount of recycled aggregate 4 and discharges it by opening a gate provided at the bottom. The recycled aggregate 4 discharged from the bucket 525 is transported by a trolley device, a belt conveyor, or the like, although not shown in detail, and stored in a surge bin equipped with a heat retaining function.

The cold hopper 522 is connected to a second flue 53 for exhausting the exhaust gas generated by heating the recycled aggregate 4 in the rotary drum 521 from the recycled aggregate drying furnace 52 . The recycled aggregate 4 contains waste asphalt. Therefore, the exhaust gas generated by heating the recycled aggregate 4 becomes a combustible gas containing about 70% oil, and also contains a large amount of hydrocarbon-based odorous components. In addition, since the crushed stone with a low particle size contained in the recycled aggregate 4 adheres to the waste asphalt, the exhaust gas of the recycled aggregate 4 does not contain fine dust compared to the exhaust gas of the new aggregate 2 .

The primary dust collector 54 and the second exhaust fan 55 are connected in this order to the second flue 53 . An inertial dust collector is used for the primary dust collector 54 as in the new aggregate drying line 3 described above. The second exhaust fan 55 sucks exhaust gas from the recycled aggregate drying furnace 52 through the primary dust collector 54 . As the second exhaust fan 55, an exhaust fan is used in which the amount of exhaust air can be adjusted by inverter-controlling a drive motor.

The first flue 33 and the second flue 53 are collectively connected to the third flue 7 . A regenerative combustion type deodorizing device 8, a third exhaust fan 9, and a chimney 10 are connected to the third flue 7 in this order. That is, the third flue 7 mixes the exhaust gas generated in the new aggregate drying furnace 32 and the exhaust gas generated in the recycled aggregate drying furnace 52 and supplies the mixture to the regenerative combustion type deodorizer 8 . The regenerative combustion type deodorizing device 8 includes a combustion chamber 810 (see FIG. 7) having a deodorizing burner 82 and two or more regenerative chambers 811, 812, 813 (see FIG. 7) respectively communicating with the combustion chamber 810. I have. The deodorizing burner 82 corresponds to an example of the first burner of the present invention. The regenerative combustion type deodorizing device 8 supplies the exhaust gas mixed by the third flue 7 to one heat storage chamber to preheat it, and heats the odorous components of the preheated exhaust gas in the combustion chamber 810 with the deodorizing burner 82 . oxidatively decomposes. Further, the regenerative combustion type deodorizer 8 recovers heat from the exhaust gas in which the malodorous components are oxidatively decomposed in another regenerative chamber, and then discharges the exhaust gas to the third flue 7 .

The third exhaust fan 9 sucks the exhaust gas deodorized by the regenerative combustion type deodorizing device 8 . As the third exhaust fan 9, an exhaust fan is used in which the amount of exhaust air can be adjusted by inverter-controlling a drive motor. The chimney 10 corresponds to an example of the exhaust port of the present invention, and discharges the deodorized exhaust gas sucked by the third exhaust fan 9 into the atmosphere.

According to the asphalt plant 1 of the present embodiment, the exhaust gas from the new aggregate drying furnace 32 and the exhaust gas from the reclaimed aggregate drying furnace 52 can be deodorized by one regenerative combustion type deodorizing device 8 . When the exhaust gas from the new aggregate drying furnace 32 and the exhaust gas from the recycled aggregate drying furnace 52 are separately supplied to the regenerative combustion deodorizing device 8, the exhaust gas in the regenerative combustion deodorizing device 8 contains oil and odor. Concentration unevenness occurs in the components, etc., and there is a possibility that deodorization of the exhaust gas will not be performed appropriately. However, in the asphalt plant 1 of the present embodiment, the exhaust gas generated in the new aggregate drying furnace 32 and the exhaust gas generated in the recycled aggregate drying furnace 52 are collected and mixed by the third flue 7. , exhaust gas with no concentration unevenness can be supplied to the regenerative combustion type deodorizing device 8 .

The mixing line 6 shown in FIG. 2 includes the new aggregate 2 heated and dried in the new aggregate drying line 3, the recycled aggregate 4 heated and dried in the recycled aggregate drying line 5, and externally supplied Asphalt 11, stone powder 12 and the like are weighed and put into a mixer 13. - 特許庁The stone powder 12 is an aggregate having a particle size lower than that of the new aggregate 2 and the recycled aggregate 4 and is a filler filled between the new aggregate 2 and the recycled aggregate 4 . The mixer 13 mixes the new aggregate 2, the recycled aggregate 4, the asphalt 11, the stone dust 12, and the like to produce an asphalt mixture 14. The asphalt mixture 14 discharged from the mixer 13 is transported by a trolley device, a hot elevator, or the like (not shown in detail) and stored in a mixture storage bin equipped with a heat insulating function.

The new aggregate drying furnace 32 includes a first pressure sensor 325 corresponding to an example of the first internal pressure measuring means of the present invention. The first pressure sensor 325 measures the internal pressure of the new aggregate drying furnace 32 . The internal pressure of the new aggregate drying furnace 32 changes according to the amount of combustion of the drying burner 324, and increases as the amount of combustion of the drying burner 324 increases. Also, the combustion amount of the drying burner 324 is adjusted according to the amount of the new aggregates 2 supplied to the rotary drum 321, and is adjusted so that the combustion amount increases as the amount of the new aggregates 2 increases. That is, the internal pressure of the new aggregate drying furnace 32 increases as the amount of the new aggregate 2 supplied to the rotating drum 321 increases. As shown in FIG. 3, the first pressure sensor 325 transmits the measured internal pressure of the new aggregate drying furnace 32 to the controller 15 as a measurement signal.

The control device 15 corresponds to an example of the control means of the present invention, and controls the first exhaust fan 36, the second exhaust fan 55 and the third exhaust fan 9 in an integrated manner. The control device 15 is composed of, for example, one or more computers and control software installed in the computers. Although not shown in detail, the computer that constitutes the control device 15 includes a storage that stores control software and various setting data related thereto, and a RAM that temporarily stores the control software and setting data read from the storage. , and a CPU that executes the control software read into the RAM. The computer also receives measurement signals sent from the first pressure sensor 325 or the like, and sends control signals to the first blower 36, the second blower 55 and the third blower 9. , and an I/O interface communicatively connected to them.

As shown in FIG. 3 , the control device 15 calculates the exhaust air volume of the first exhaust fan 36 based on the internal pressure of the new aggregate drying furnace 32 measured by the first pressure sensor 325 . Specifically, as shown in the graph of FIG. 4, the control device 15 controls the first exhaust fan 36 so that the higher the internal pressure of the new aggregate drying furnace 32, the larger the exhaust air volume of the first exhaust fan 36. 36 is calculated. In addition, it is preferable that the calculated exhaust air volume of the first exhaust fan 36 is the minimum exhaust air volume at which exhaust gas and dust do not blow out from the new aggregate drying furnace 32 . The control device 15 drives the first exhaust fan 36 based on the calculated exhaust air volume.

Further, the recycled aggregate drying furnace 52 includes a second pressure sensor 526 corresponding to an example of the second internal pressure measuring means of the present invention. The second pressure sensor 526 measures the internal pressure of the recycled aggregate drying furnace 52 . The inner pressure of the recycled aggregate drying furnace 52 increases as the amount of recycled aggregate 4 supplied to the rotating drum 521 increases, similarly to the new aggregate drying furnace 32 . As shown in FIG. 3, the second pressure sensor 526 transmits the measured internal pressure of the recycled aggregate drying furnace 52 to the control device 15 as a measurement signal.

As shown in FIG. 3 , the control device 15 calculates the exhaust air volume of the second exhaust fan 55 based on the internal pressure of the recycled aggregate drying furnace 52 measured by the second pressure sensor 526 . Specifically, similarly to the first exhaust fan 36, the control device 15 controls the second exhaust fan 55 such that the higher the internal pressure of the recycled aggregate drying furnace 52, the larger the exhaust air volume of the second exhaust fan 55. The exhaust air volume of the fan 55 is calculated. It is preferable that the calculated exhaust air volume of the second exhaust fan 55 is the minimum exhaust air volume at which the exhaust gas and dust are not blown out from the recycled aggregate drying furnace 52 . The control device 15 drives the second exhaust fan 55 based on the calculated exhaust air volume.

The regenerative combustion deodorizing device 8 includes a third pressure sensor 83 corresponding to an example of the third internal pressure measuring means of the present invention. A third pressure sensor 83 measures the internal pressure of the regenerative combustion deodorizing device 8 . The internal pressure of the regenerative combustion deodorizing device 8 changes according to the amount of exhaust gas discharged from the new aggregate drying furnace 32 and the recycled aggregate drying furnace 52, and increases as the amount of discharged exhaust gas increases. The amount of exhaust gas discharged from the new aggregate drying furnace 32 changes according to the amount of the new aggregate 2 supplied to the new aggregate drying furnace 32, and increases as the amount of the new aggregate 2 supplied increases. . Similarly, the amount of exhaust gas discharged from the recycled aggregate drying furnace 52 changes according to the amount of recycled aggregate 4 supplied to the recycled aggregate drying furnace 52, and increases as the amount of recycled aggregate 4 supplied increases. do. As shown in FIG. 3, the third pressure sensor 83 transmits the measured internal pressure of the regenerative combustion deodorizing device 8 to the control device 15 as a measurement signal.

As shown in FIG. 3, the control device 15 calculates the exhaust air volume of the third exhaust fan 9 based on the internal pressure of the regenerative combustion deodorizing device 8 measured by the third pressure sensor 83 . Specifically, the control device 15 increases the exhaust air volume of the third exhaust fan 9 as the internal pressure of the regenerative combustion deodorizing device 8 increases, similarly to the first exhaust fan 36 and the second exhaust fan 55. The exhaust air volume of the third exhaust fan 9 is calculated as follows. In addition, it is preferable that the calculated exhaust air volume of the third exhaust fan 9 is the minimum exhaust air volume at which exhaust gas and dust do not blow out from the regenerative combustion type deodorizing device 8 . The control device 15 drives the third exhaust fan 9 based on the calculated exhaust air volume.

As described above, the asphalt plant 1 of the present embodiment uses the asphalt mixture using only the new aggregate 2, the asphalt mixture using only the recycled aggregate 4, the new aggregate 2, and the recycled aggregate 4. Three types of mixed asphalt mixtures can be produced. Moreover, when producing an asphalt mixture using the new aggregate 2 and the recycled aggregate 4, the new aggregate 2 and the recycled aggregate 4 can be mixed at an arbitrary ratio. That is, the amount of exhaust gas generated in the new aggregate drying furnace 32 and the recycled aggregate drying furnace 52 and the amount of exhaust gas deodorized by the regenerative combustion deodorizing device 8 vary depending on the type of asphalt mixture to be produced. do. In order to cope with this fluctuating exhaust gas amount, in the asphalt plant 1 of the present embodiment, the new aggregate drying furnace 32, the recycled aggregate drying furnace 52, and the regenerative combustion deodorizing device 8 are each independently controlled as follows. One exhaust fan 36, a second exhaust fan 55 and a third exhaust fan 9 are installed. Therefore, the first exhaust fan 36, the second exhaust fan 55, and the third exhaust fan 9 are controlled independently, and the new aggregate drying furnace 32, the recycled aggregate drying furnace 52, and the regenerative combustion type Exhaust gas from the deodorizing device 8 can be discharged with an optimum amount of exhaust air.

Further, according to the asphalt plant 1 of the present embodiment, the first exhaust fan 36, the second exhaust fan 55 and the third exhaust fan 9 have different first flue 33 and second flue 53, respectively. and the third flue 7, there is no need to consider the influence of the flue in which the other fans are installed when calculating and controlling the exhaust air volume of each fan. Therefore, the calculation and control of the exhaust air volume become easy, and the processing load required for controlling the first exhaust fan 36, the second exhaust fan 55, and the third exhaust fan 9 can be reduced. Furthermore, based on the measurement results of the first pressure sensor 325, the second pressure sensor 526, and the third pressure sensor 83, the first exhaust fan 36 and the second exhaust fan 36 are arranged so that the higher the internal pressure, the larger the exhaust air volume. The exhaust air volumes of the exhaust fan 55 and the third exhaust fan 9 are calculated. Therefore, the first exhaust fan 36, the second exhaust fan 55, and the third exhaust fan 9 can be driven with an optimum amount of exhaust air corresponding to the internal pressure of the new aggregate drying furnace 32 and the like. In addition, the exhaust air volume of the first exhaust fan 36, the second exhaust fan 55 and the third exhaust fan 9 is preferably set to The amount of exhaust air is calculated to be the minimum amount that does not blow off the exhaust gas and dust from the device 8 . Therefore, while preventing exhaust gas and dust from blowing out from the new aggregate drying furnace 32, the recycled aggregate drying furnace 52, and the regenerative combustion deodorizing device 8, the first exhaust fan 36, the second exhaust fan 55, and the second exhaust fan 3, the power consumption of the exhaust fan 9 can be suppressed.

Next, the drying furnace 52 for recycled aggregate of this embodiment will be described. FIG. 5 shows the various zones that occur within the rotating drum 521 of the recycled aggregate drying oven 52 . Each zone will be described in order from the cold hopper 522 side. In addition, in FIG. 5, the drying furnace 52 for recycled aggregate is drawn in a non-tilted state. In the backflow prevention zone, backflow prevention vanes 521b provided on the inner surface of the rotating drum 521 prevent the recycled aggregate 4 supplied to the rotating drum 521 from flowing back to the cold hopper 522 side. In the agitation preheat zone, the recycled aggregate 4 is agitated by the raking blades 521a and dried by blowing hot air generated by the flame of the drying burner 524. FIG. Thereby, the recycled aggregate 4 is dried mainly in the backflow prevention zone and the agitation preheat zone.

The stirring and heating zone is a zone in which the recycled aggregate 4 is stirred by the raking blades 521 a and directly heated by the flame of the drying burner 524 . Similarly, the heating zone is a zone in which the recycled aggregate 4 is heated by the flame of the drying burner 524 . The recycled aggregate 4 is heated to a temperature necessary for mixing with the asphalt mainly by the stirring heating zone and the heating zone. The final discharge zone is a zone for sieving the recycled aggregates 4 by a grid portion 521c provided at the end of the rotating drum 521 and discharging the sieved recycled aggregates 4 from a discharge port 523a.

In the conventional asphalt plant, in order to reduce the temperature difference between the hot air and the recycled aggregate 4 and to reduce the deterioration of the asphalt contained in the recycled aggregate 4, the flow direction of the recycled aggregate 4 and the flame of the drying burner A direct-fire co-current drying furnace in which the radial direction of the heat is the same is generally used. However, as a result of investigation by the inventors of the present application, it was confirmed that even if the recycled aggregate 4 is heated with an open flame, there is no difference in deterioration compared to the case of heating with hot air. In addition, in the direct fire countercurrent type, the recycled aggregate 4 is dried by hot air, heated by direct fire, and then discharged. It was found that high thermal efficiency can be obtained with Furthermore, as shown in Table 1 below, the direct fire countercurrent system can significantly reduce the exhaust gas temperature, odor index, and odor concentration compared to the direct fire parallel current system, confirming that the environmental load is small. It is Therefore, the direct-fired countercurrent type drying furnace can use a deodorizing device with a lower processing capacity than the direct-fired direct-current type, so that the cost can be reduced. For these reasons, the present embodiment uses the direct-heated countercurrent type recycled aggregate drying furnace 52 which has higher thermal efficiency than the direct-fired cocurrent type and has less environmental load.

As shown in FIG. 6, a direct heat countercurrent reclaimed aggregate drying furnace is a reclaimed aggregate drying furnace in which the outer circumference of the flame emitted from a drying burner 524 is covered with a metal cylindrical member 527 . Furnace 52A may be used. According to the recycled aggregate drying furnace 52A, since the flame of the drying burner 524 does not directly contact the recycled aggregate 4, the temperature of the recycled aggregate 4 rises too much and the asphalt contained in the recycled aggregate 4 deteriorates. can prevent

Next, the regenerative combustion deodorizing device 8 of this embodiment will be described. As shown in FIG. 7, the regenerative combustion deodorizing device 8 is a so-called three-tower regenerative combustion deodorizing device, and includes a device main body 81, a deodorizing burner 82, an exhaust gas supply duct 84, an exhaust duct 85, and a purge air supply duct 86 . The apparatus main body 81 includes a combustion chamber 810 having a deodorizing burner 82 and three heat storage chambers 811, 812 and 813 arranged below the combustion chamber 810 and communicating with the combustion chamber 810, respectively. The third pressure sensor 83 is attached to the combustion chamber 810 . The three heat storage chambers 811, 812 and 813 incorporate heat storage bodies 811a, 812a and 813a, respectively. The heat storage bodies 811a, 812a, and 813a can be made of ceramic or metal and formed in a honeycomb shape, for example, in order to divide and form a plurality of gas flow paths to improve the efficiency of heat transfer with the exhaust gas. .

One end of the exhaust gas supply duct 84 is connected to the third flue 7 on the upstream side of the regenerative combustion type deodorizing device 8, and the other end is branched and connected to the heat storage chambers 811 to 813, respectively. The exhaust gas supply duct 84 has three on-off valves 841, 842 and 843 for selectively switching which of the heat storage chambers 811 to 813 to be connected. One end of the exhaust duct 85 is connected to the third flue 7 on the downstream side of the regenerative combustion type deodorizing device 8, and the other end is branched and connected to the heat storage chambers 811 to 813, respectively. The exhaust duct 85 has three on-off valves 851, 852 and 853 for selectively switching which of the heat storage chambers 811 to 813 to be connected. Although not shown in detail, one end of the purge air supply duct 86 is connected to the exhaust duct 85, and the other end is branched and connected to each of the heat storage chambers 811-813. The purge air supply duct 86 has three on-off valves 861, 862 and 863 for selectively switching which of the heat storage chambers 811 to 813 to be connected. As a result, deodorized clean air is supplied as purge air. Note that dampers may be used as the on-off valves 841-843, 851-853 and 861-863.

FIG. 8 shows three operation cycles (A) to (C) for deodorizing exhaust gas with a three-tower regenerative combustion type deodorizing device 8 . The regenerative combustion type deodorizing device 8 ignites the deodorizing burner 82 at the start of operation, adjusts the temperature of the deodorizing burner 82 based on the measurement result of a temperature sensor (not shown), and adjusts the temperature in the combustion chamber 810 to reduce the odor of the exhaust gas. The temperature is raised to a set temperature T1 (eg, 750 to 850° C., eg, 800±20° C. in this embodiment) at which the components can be oxidatively decomposed.

In the operation cycle (A), the on-off valve 841 of the exhaust gas supply duct 84, the on-off valve 852 of the exhaust duct 85, and the on-off valve 863 of the purge air supply duct 86 are opened, and the other on-off valves are closed. As a result, the exhaust gas passes through the heat storage chamber 811 , the combustion chamber 810 and the heat storage chamber 812 and is discharged to the third flue 7 . Also, the purge air passes through the heat storage chamber 813 , the combustion chamber 810 and the heat storage chamber 812 and is discharged to the third flue 7 . That is, in this operation cycle (A), the exhaust gas is preheated by passing through the heat storage element 811a whose temperature has been raised in the previous cycle, and the temperature of the heat storage element 811a is lowered. In the preheated exhaust gas, odorous components are oxidatively decomposed in the combustion chamber 810 under a high-temperature atmosphere to become clean gas, and the temperature is lowered while preheating the heat storage element 812a (heat is recovered) and exhausted. During this time, the exhaust gas remaining in the heat storage medium 813a in the previous cycle is purged with purge air (clean gas), oxidatively decomposed in the combustion chamber 810, and then exhausted via the heat storage medium 812a.

After a certain period of time has passed in the operation cycle (A), the operation cycle (B) is entered. In the operation cycle (B), the on-off valve 842 of the exhaust gas supply duct 84, the on-off valve 853 of the exhaust duct 85, and the on-off valve 861 of the purge air supply duct 86 are opened, and the other on-off valves are closed. As a result, the exhaust gas passes through the heat storage chamber 812 , the combustion chamber 810 and the heat storage chamber 813 and is discharged to the third flue 7 . Also, the purge air passes through the heat storage chamber 811 , the combustion chamber 810 and the heat storage chamber 813 and is discharged to the third flue 7 . That is, in this operation cycle (B), the exhaust gas is preheated by passing through the heat storage element 812a whose temperature has been raised in the operation cycle (A), and the temperature of the heat storage element 812a is lowered. In the preheated exhaust gas, odorous components are oxidatively decomposed in the combustion chamber 810 to become clean gas. In the meantime, the exhaust gas remaining in the heat storage medium 811a in the operation cycle (A) is purged with purge air, oxidatively decomposed in the combustion chamber 810, and then exhausted via the heat storage medium 813a.

After a certain period of time has passed in the operation cycle (B), the operation cycle (C) is entered. In the operation cycle (C), the on-off valve 843 of the exhaust gas supply duct 84, the on-off valve 851 of the exhaust duct 85, and the on-off valve 862 of the purge air supply duct 86 are opened. As a result, the exhaust gas passes through the heat storage chamber 813 , the combustion chamber 810 and the heat storage chamber 811 and is discharged to the third flue 7 . Also, the purge air passes through the heat storage chamber 812 , the combustion chamber 810 and the heat storage chamber 811 and is discharged to the third flue 7 . That is, in this operation cycle (C), the exhaust gas is preheated by passing through the heat storage element 813a whose temperature has been raised in the operation cycle (B), and the temperature of the heat storage element 813a is lowered. In the preheated exhaust gas, odorous components are oxidatively decomposed in the combustion chamber 810 to become clean gas. In the meantime, the exhaust gas remaining in the heat storage medium 812a in the operation cycle (B) is purged with purge air, oxidatively decomposed in the combustion chamber 810, and then exhausted via the heat storage medium 811a. After a certain period of time has passed in the operation cycle (C), the operation cycle is shifted to the operation cycle (A).

The regenerative combustion deodorizing device 8 removes the odorous components of the exhaust gas from the new aggregate drying furnace 32 and the recycled aggregate drying furnace 52 by sequentially repeating the three operation cycles (A) to (C) described above. Oxidative decomposition and deodorization. Since the regenerative combustion type deodorizing device 8 preheats and recovers heat from the exhaust gas using the heat storage elements 811a to 813a, the thermal efficiency of the asphalt plant 1 can be increased and the fuel consumption necessary for deodorizing the exhaust gas can be reduced. In addition, since the regenerative combustion type deodorizing device 8 purges the residual gas of the regenerators 811a to 813a that are not used for preheating and heat recovery, clogging of the regenerators 811a to 813a can be suppressed and maintenance frequency can be reduced. can be done.

Thus, by adopting the regenerative combustion type deodorizing device 8 in the asphalt plant 1, the thermal efficiency of the asphalt plant 1 can be increased and the fuel consumption required for deodorizing the exhaust gas can be reduced. However, conventional asphalt plants generally employ direct combustion deodorizers, and there are few examples of the use of regenerative combustion deodorizers. There is a known example of using a regenerative combustion deodorizing device in a recycled aggregate recycling plant. In some cases, the temperature became higher than necessary for oxidative decomposition of the components, and the regenerative combustion type deodorizer was forced to stop in order to protect the combustion chamber. For example, if an asphalt plant employs a regenerative combustion deodorizing device and the regenerative combustion deodorizing device is forcibly stopped, the production of the asphalt mixture itself will be delayed.

On the other hand, in the asphalt plant 1 of the present embodiment, the exhaust gas from the new aggregate drying furnace 32 and the exhaust gas from the recycled aggregate drying furnace 52 are mixed and supplied to the regenerative combustion type deodorizing device 8, and regenerative combustion is performed. Since the oil content of the exhaust gas in the deodorizing device 8 is low, combustion of the exhaust gas in the combustion chamber 810 can be prevented. Therefore, according to this embodiment, the asphalt plant 1 can employ the regenerative combustion deodorizing device 8, which has been difficult to employ in the past.

Next, the operation of this embodiment will be described with reference to the flowchart shown in FIG. The asphalt plant 1 heats and dries the new aggregate 2 in the new aggregate drying furnace 32 (step S1). At that time, the first pressure sensor 325 measures the internal pressure of the new aggregate drying furnace 32 and transmits a measurement signal to the control device 15 . Based on the measurement signal, the controller 15 determines that the higher the internal pressure of the new aggregate drying furnace 32 is, the larger the exhaust air volume of the first exhaust fan 36 is, and the more the exhaust gas and dust are discharged from the new aggregate drying furnace 32 . The amount of exhausted air from the first exhaust fan 36 is calculated so as to obtain the minimum amount of exhausted air that does not blow out. Further, the control device 15 drives the first exhaust fan 36 based on the calculated exhaust air volume. The new aggregate 2 heated and dried by the new aggregate drying furnace 32 is transported by a trolley device, a hot elevator, or the like, and stored in a hot bin having a heat retaining function.

In parallel with step S1, the asphalt plant 1 heats and dries the recycled aggregate 4 in the recycled aggregate drying furnace 52 (step S2). At that time, the second pressure sensor 526 measures the internal pressure of the recycled aggregate drying furnace 52 and transmits a measurement signal to the control device 15 . Based on the measurement signal, the control device 15 controls that the higher the internal pressure of the recycled aggregate drying furnace 52 is, the larger the exhaust air volume of the second exhaust fan 55 is and the more the exhaust gas and dust are discharged from the recycled aggregate drying furnace 52 . The amount of exhausted air from the second exhaust fan 55 is calculated so as to obtain the minimum amount of exhausted air that does not blow out. Further, the control device 15 drives the second exhaust fan 55 based on the calculated exhaust air volume. The recycled aggregate 4 heated and dried by the recycled aggregate drying furnace 52 and discharged is transported by a trolley device or a belt conveyor and stored in a surge bin having a heat retaining function.

The exhaust gas sent out from the new aggregate drying furnace 32 by the first exhaust fan 36 is sent to the third flue 7 through the first flue 33 . The exhaust gas sent out from the recycled aggregate drying furnace 52 by the second exhaust fan 55 is sent to the third flue 7 through the second flue 53 . As a result, the exhaust gas from the new aggregate drying furnace 32 and the exhaust gas from the recycled aggregate drying furnace 52 are mixed in the third flue 7 . The mixed exhaust gas is supplied to the regenerative combustion deodorizing device 8 .

In parallel with steps S1 and S2, the asphalt plant 1 deodorizes the mixed exhaust gas from the drying furnace 32 for new aggregates and the mixed exhaust gas from the drying furnace 52 for recycled aggregates by the regenerative combustion type deodorizing device 8. (Step S3). At that time, the third pressure sensor 83 measures the internal pressure of the regenerative combustion deodorizing device 8 and transmits a measurement signal to the control device 15 . Based on the measurement signal, the controller 15 determines that the higher the internal pressure of the regenerative combustion deodorizing device 8, the greater the amount of exhaust air from the third exhaust fan 9 and the more exhaust gas and dust are blown out from the regenerative combustion deodorizing device 8. The amount of exhaust air from the third exhaust fan 9 is calculated so as to achieve the minimum amount of exhaust air that does not occur. Further, the control device 15 drives the third exhaust fan 9 based on the calculated exhaust air volume.

In the asphalt plant 1, in parallel with steps S1 to S3, or after a predetermined amount of dried new aggregate 2 and recycled aggregate 4 are stored in steps S1 to S3, the new aggregate 2 is mixed by the mixer 13. , recycled aggregate 4, asphalt 11, stone powder 12, etc. are mixed to produce an asphalt mixture 14. The asphalt mixture 14 is discharged from the mixer 13, conveyed by a trolley device, a hot elevator, or the like, and stored in a mixture storage bin equipped with a heat insulating function.

As described above, the asphalt plant 1 of the present embodiment includes the new aggregate drying furnace 32 for drying the new aggregate 2, the recycled aggregate drying furnace 52 for drying the recycled aggregate 4, the new aggregate The new aggregate 2 dried in the material drying furnace 32, the recycled aggregate 4 dried in the recycled aggregate drying furnace 52, the mixer 13 for mixing the asphalt 11, etc., and the new aggregate drying furnace 32 A regenerative combustion type deodorizing device 8 is provided for heating the generated exhaust gas and the exhaust gas generated in the recycled aggregate drying furnace 52 to oxidize and decompose odorous components. According to this configuration, the exhaust gas from the new aggregate drying furnace 32 and the exhaust gas from the reclaimed aggregate drying furnace 52 can be deodorized by one regenerative combustion type deodorizing device 8 . In addition, since it is not necessary to install a new deodorizing device in order to deodorize the exhaust gas of the new aggregate drying furnace 32, the fuel cost of the deodorizing device and the amount of CO ₂ are reduced compared to the case of installing a new deodorizing device. Emissions can be reduced.

In the asphalt plant 1 of the present embodiment, the exhaust gas generated in the new aggregate drying furnace 32 and the exhaust gas generated in the recycled aggregate drying furnace 52 are combined and supplied to the regenerative combustion deodorizing device 8. 3 flues 7 are provided. According to this configuration, the exhaust gas generated in the new aggregate drying furnace 32 and the exhaust gas generated in the recycled aggregate drying furnace 52 are mixed in the third flue 7, so that oil, odor components, etc. are mixed. can be supplied to the regenerative combustion type deodorizing device 8.

Furthermore, the asphalt plant 1 of the present embodiment includes a first exhaust fan 36 that sends out the exhaust gas generated in the new aggregate drying furnace 32 to the regenerative combustion deodorizing device 8, and the exhaust gas generated in the recycled aggregate drying furnace 52. to the regenerative combustion deodorizing device 8, and a third exhaust fan 9 feeding the exhaust gas deodorized by the regenerative combustion deodorizing device 8 to the chimney 10. According to this configuration, depending on the type of asphalt mixture 14 to be manufactured, the amount of exhaust gas generated in the new aggregate drying furnace 32, the amount of exhaust gas generated in the recycled aggregate drying furnace 52, and the heat storage combustion type Even when the amount of exhaust gas deodorized by the deodorizing device 8 fluctuates, the first exhaust fan 36, the second exhaust fan 55, and the third exhaust fan 9 operate the drying furnace 32 for new aggregate and the drying furnace 32 for recycled aggregate. The exhaust gas from the drying furnace 52 and the regenerative combustion type deodorizing device 8 can be discharged with the optimum amount of exhaust air.

In addition, the asphalt plant 1 of the present embodiment includes a first flue 33 connected to the new aggregate drying furnace 32 and a second flue 53 connected to the recycled aggregate drying furnace 52. , and a third flue 7 in which the first flue 33 and the second flue 53 are assembled. A first exhaust fan 36 is installed in the first flue 33, a second exhaust fan 55 is installed in the second flue 53, and a third exhaust fan 9 is installed in the third flue 7. is installed in According to this configuration, when calculating and controlling the amount of exhaust air from each exhaust fan, it is not necessary to consider the influence of the flue in which the other exhaust fans are installed. Therefore, the calculation and control of the exhaust air volume become easy, and the processing load required for controlling the first exhaust fan 36, the second exhaust fan 55, and the third exhaust fan 9 can be reduced.

Furthermore, the asphalt plant 1 of this embodiment includes a first pressure sensor 325 that measures the internal pressure of the new aggregate drying furnace 32, and a second pressure sensor 526 that measures the internal pressure of the recycled aggregate drying furnace 52. , a third pressure sensor that measures the internal pressure of the heat storage combustion type deodorizing device 8, a first exhaust fan 36, a second exhaust fan 55, and a control device 15 that controls the third exhaust fan 9, It has Then, the control device 15 controls the exhaust air volume of the first exhaust fan 36 based on the measurement result of the first pressure sensor 325, and controls the second exhaust fan 36 based on the measurement result of the second pressure sensor 526. The amount of air exhausted from the fan 55 is controlled, and the amount of air exhausted from the third exhaust fan 9 is controlled based on the measurement result of the third pressure sensor 83 . According to this, the first exhaust fan 36, the second exhaust fan 55 and the second Since the exhaust air volume of the exhaust fan 9 of No. 3 is controlled, the exhaust gas from the new aggregate drying furnace 32, the recycled aggregate drying furnace 52, and the regenerative combustion type deodorizing device 8 can be discharged at optimum exhaust air volumes.

In the asphalt plant 1 of the present embodiment, the recycled aggregate drying furnace 52 is supported so as to be rotatable about an inclined axis, and the stored recycled aggregate 4 is stirred along the inclination. A cylindrical rotating drum 521 for flowing, a cold hopper 522 for supplying recycled aggregates 4 into the rotating drum 521 from one end at a high position among both ends of the rotating drum 521, and the other end of the rotating drum 521. A drying burner 524 for heating the reclaimed aggregate 4 by radiating flame into the rotating drum 521 from a direct flame countercurrent type. Therefore, as compared with the conventional direct-fire parallel-flow drying method, it is possible to reduce the environmental load while obtaining high thermal efficiency.

Further, in the asphalt plant 1 of the present embodiment, the recycled aggregate drying furnace 52A is provided with a cylindrical member 527 that surrounds the flame of the drying burner 524 within the rotating drum 521 . As a result, the flame of the drying burner 524 does not come into direct contact with the recycled aggregate 4, so that the temperature of the asphalt contained in the recycled aggregate 4 is prevented from rising too high and deteriorating.

In addition, the asphalt plant 1 of the present embodiment includes a combustion chamber 810 having a deodorizing burner 82 as a deodorizing device, and two or more heat storage chambers 811 to 813 communicating with the combustion chamber 810, respectively. Exhaust gas from the drying furnace 32 and the drying furnace 52 for recycled aggregates is supplied to one heat storage chamber and preheated, and the preheated exhaust gas is heated by the deodorizing burner 82 in the combustion chamber 810 to oxidize and decompose the odorous components, A regenerative combustion type deodorizer 8 is used in which heat is recovered from the exhaust gas in which the odorous components are oxidized and decomposed in another regenerative chamber and then discharged. According to this, since the exhaust gas is preheated and heat-recovered using the heat storage bodies 811a to 813a, the thermal efficiency of the asphalt plant 1 can be enhanced and the fuel consumption necessary for deodorizing the exhaust gas can be suppressed. Further, the exhaust gas from the new aggregate drying furnace 32 and the exhaust gas from the recycled aggregate drying furnace 52 are mixed and supplied to the regenerative combustion deodorizing device 8, and the oil concentration of the exhaust gas in the regenerative combustion deodorizing device 8 is adjusted to Since it is lowered, it is possible to prevent exhaust gas from burning in the combustion chamber 810 and forcibly stopping the regenerative combustion deodorizing device 8 to protect the combustion chamber 810 .

<<Second embodiment>>
Next, a second embodiment will be described in which the amount of exhaust air from the third exhaust fan 9 is controlled by a method different from that of the first embodiment. Note that detailed descriptions of the same configurations as those of the first embodiment will be omitted. As shown in FIG. 3, the control device 15 of the first embodiment calculates the exhaust air volume of the third exhaust fan 9 based on the internal pressure of the regenerative combustion deodorizing device 8 measured by the third pressure sensor 83. , the amount of exhaust air from the third exhaust fan 9 is controlled based on the calculation results. On the other hand, the control device 15A of this embodiment shown in FIG. Based on the measurement result of 83, the exhaust air volume of the third exhaust fan 9 is calculated, and the exhaust air volume of the third exhaust fan 9 is controlled based on the computation result.

For example, when the exhaust air volume of the first exhaust fan 36 is 30 m ³ /min and the exhaust air volume of the second exhaust fan 55 is 20 m ³ /min, the control device 15A adds these exhaust air volumes and adds Based on the exhaust air volume of 50 m ³ /min and the measurement result of the third pressure sensor 83, the exhaust air volume of the third exhaust fan 9 is calculated so that the exhaust gas and dust are not blown out from the regenerative combustion deodorizer 8. Further, the control device 15A controls the exhaust air volume of the third exhaust fan 9 based on the calculation result.

In the first embodiment, when the amount of exhaust air from the first exhaust fan 36 and the second exhaust fan 55 changes, the internal pressure of the regenerative combustion type deodorizing device 8 changes according to the change in the exhaust air amount. The exhaust air volume of the third exhaust fan 9 is controlled based on the change in the internal pressure of the deodorizing device 8 . That is, in the first embodiment, there is a time lag between the change in the amount of exhaust air from the first exhaust fan 36 and the second exhaust fan 55 and the control of the amount of exhaust air from the third exhaust fan 9. Therefore, exhaust gas and dust may blow out from the regenerative combustion type deodorizing device 8 before control of the exhaust air volume of the third exhaust fan 9 is started. However, according to this embodiment, the amount of air exhausted by the third exhaust fan 9 is controlled based on the amount of air exhausted by the first exhaust fan 36 and the amount of air exhausted by the second exhaust fan 55. It is possible to shorten the time lag between when the exhaust air volume of the exhaust fan 36 and the second exhaust fan 55 is changed and when the exhaust air volume of the third exhaust fan 9 is controlled, and the heat storage combustion type deodorizing device 8 It is possible to prevent exhaust gas and the like from blowing out.

In each of the above embodiments, the regenerative combustion type deodorizing device 8 is used as the deodorizing device, but a direct combustion type deodorizing device that raises the furnace temperature with a burner may be used. Further, in the second embodiment, based on the calculation result of the exhaust air volume of the first exhaust fan 36, the calculation result of the exhaust air volume of the second exhaust fan 55, and the measurement result of the third pressure sensor 83, Although the exhaust air volume of the third exhaust fan 9 is controlled, the exhaust air volume of the third exhaust fan 9 may be controlled without using the measurement result of the third pressure sensor 83 . According to this, it is possible to further shorten the time lag between the change in the amount of exhaust air from the first exhaust fan 36 and the second exhaust fan 55 and the control of the amount of exhaust air from the third exhaust fan 9. can be done. Also, when only the recycled aggregate drying line 5 is operated to produce an asphalt mixture, the exhaust gas from the recycled aggregate drying furnace 52 may burn in the regenerative combustion deodorizing device 8 depending on the oil content of the exhaust gas. In this case, the first exhaust fan 36 of the new aggregate drying line 3 may be operated to lower the oil concentration of the exhaust gas. Further, in each of the above-described embodiments, an example of using the direct fire countercurrent type recycled aggregate drying furnace 52 has been described, but instead of the direct fire countercurrent type recycled aggregate drying furnace 52, a direct fire parallel flow dryer has been described. A drying furnace for recycled aggregates of the type may be used.

1... Asphalt plant 2... New aggregate 3... New aggregate drying line 32... Drying furnace for new aggregate 321... Rotating drum 322... Cold hopper 323... Hot hopper 324... Drying burner 325... First pressure sensor (second 1 internal pressure measuring means)
36 First exhaust fan 4 Recycled aggregate 5 Recycled aggregate drying line 52 Recycled aggregate drying furnace 521 Rotating drum 522 Cold hopper 523 Hot hopper 524 Drying burner (second burner)
526... Second pressure sensor (second internal pressure measuring means)
527 Cylindrical member 55 Second exhaust fan 6 Mixing line 7 Third flue 8 Regenerative combustion type deodorizing device 810 Combustion chamber 811 to 813 Regenerative chamber 82 Deodorizing burner (first burner)
83... Third pressure sensor (third internal pressure measuring means)
9... Third exhaust fan 15... Control device (control means)

Claims (7)

a new aggregate drying furnace for drying the new aggregate;
a recycled aggregate drying furnace for drying the recycled aggregate;
An asphalt plant comprising a new aggregate dried in the new aggregate drying furnace, a recycled aggregate dried in the recycled aggregate drying furnace, and a mixer for mixing asphalt,
a deodorizing device that heats the exhaust gas generated in the new aggregate drying furnace and the exhaust gas generated in the recycled aggregate drying furnace to oxidize and decompose odorous components ;
a first exhaust fan for sending exhaust gas generated in the new aggregate drying furnace to the deodorizing device;
a second exhaust fan for sending exhaust gas generated in the drying furnace for recycled aggregates to the deodorizing device;
a third exhaust fan for sending the exhaust gas deodorized by the deodorizing device to an exhaust port;
a first internal pressure measuring means for measuring the internal pressure of the new aggregate drying furnace;
a second internal pressure measuring means for measuring the internal pressure of the drying furnace for recycled aggregate;
A control means for controlling the first exhaust fan, the second exhaust fan, and the third exhaust fan ,
The control means is
controlling the exhaust air volume of the first exhaust fan based on the measurement result of the first internal pressure measuring means;
controlling the exhaust air volume of the second exhaust fan based on the measurement result of the second internal pressure measuring means;
An asphalt plant that controls the amount of exhaust air from the third exhaust fan based on the amount of exhaust air from the first exhaust fan and the amount of exhaust air from the second exhaust fan.
An asphalt plant according to claim 1,
The deodorizing device includes a combustion chamber having a first burner and two or more heat storage chambers respectively communicating with the combustion chamber, and exhaust gas from the new aggregate drying furnace and the recycled aggregate drying furnace is supplied to one of the heat storage chambers for preheating, the preheated exhaust gas is heated by the first burner in the combustion chamber to oxidatively decompose the malodorous components, and the exhaust gas in which the malodorous components are oxidatively decomposed is transferred to the other The asphalt plant is a regenerative combustion type deodorizing device that recovers heat in a regenerative chamber and then discharges it.
An asphalt plant according to claim 1 ,
An asphalt plant comprising a flue for collecting the exhaust gas generated in the new aggregate drying furnace and the exhaust gas generated in the recycled aggregate drying furnace and supplying the exhaust gas to the deodorizing device.
An asphalt plant according to claim 3 ,
The flue is
a first flue connected to the new aggregate drying furnace;
a second flue connected to the drying furnace for recycled aggregate;
a third flue where the first flue and the second flue are assembled;
The first exhaust fan is installed in the first flue,
The second exhaust fan is installed in the second flue,
The asphalt plant, wherein the third exhaust fan is installed in the third flue.
The asphalt plant according to any one of claims 1 to 4 ,
The drying furnace for recycled aggregate is
a cylindrical rotating drum supported so as to be freely rotatable around an inclined axis, and agitating and flowing the contained recycled aggregates along the inclination;
Aggregate supply means for supplying recycled aggregate into the rotating drum from one end located at a higher position among both ends of the rotating drum;
an asphalt plant comprising: a second burner that radiates flame into the rotating drum from the other end side of the rotating drum to heat the recycled aggregate.
An asphalt plant according to claim 5 ,
The asphalt plant, wherein the recycled aggregate drying furnace includes a cylindrical member that surrounds the flame of the second burner in the rotating drum.
A first step of drying the new aggregate in a drying furnace for new aggregate;
a second step of drying the recycled aggregate in a drying furnace for recycled aggregate;
A method for producing an asphalt mixture, comprising a third step of mixing the new aggregate dried in the first step, the recycled aggregate dried in the second step, and asphalt with a mixer There is
a fourth step of heating the exhaust gas generated in the first step and the exhaust gas generated in the second step with a deodorizing device to oxidatively decompose malodorous components ;
a fifth step of measuring the internal pressure of the new aggregate drying furnace;
a sixth step of measuring the internal pressure of the recycled aggregate drying furnace;
a seventh step of controlling the exhaust air volume of a first exhaust fan that sends the exhaust gas generated in the first step to the deodorizing device based on the measurement result of the fifth step;
an eighth step of controlling the exhaust air volume of a second exhaust fan that sends the exhaust gas generated in the second step to the deodorizing device based on the measurement result of the sixth step;
Based on the exhaust air volume of the first exhaust fan and the exhaust air volume of the second exhaust fan, the exhaust air volume of the third exhaust fan that sends the exhaust gas deodorized in the fourth step to the exhaust port is controlled. A method for producing an asphalt mixture comprising a ninth step .

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