JPS59182855A - Process and facilities for manufacturing asphalt - Google Patents

Abstract

In the manufacture of asphalt containing at least some reclaimed asphalt material, the reclaimed asphalt is heat-exchanged with hot, dried and screened aggregate prior to mixing the reclaimed asphalt with the aggregate and with fresh bitumen.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of asphalt, and more particularly to a production method and apparatus for the production of asphalt mixtures, the starting material of which is at least in part comprised of recycled or reclaimed asphalt.

The use of recycled asphalt not only reduces the amount of virgin or new material required to produce a given batch of asphalt, but also reduces the amount of virgin material required to produce asphalt, for example, from a road surface. It is economically advantageous to solve the problem of disposing of old asphalt.

Reclaimed waste or recycled asphalt containing gravel or bitumen is not suitable for incorporation into conventional asphalt manufacturing processes.

When recycled during these conventional processes, the material is heated to a fairly high temperature to provide adequate heat transfer. At this high temperature, bitumen can deteriorate and cause contamination problems. Also, recycled materials containing bitumen become sticky upon heating and are therefore particularly difficult to handle and assimilate during the asphalt manufacturing process, especially in connection with bunch operation of the plant. Furthermore, high operating temperatures inevitably lead to high energy consumption and maintenance costs.

The present invention seeks to provide a process for producing asphalt that utilizes, at least in part, recycled asphalt as a starting material and that alleviates or minimizes the above-mentioned difficulties, and a production apparatus for carrying out such a process. It is.

According to the invention, there is provided a method for producing an asphalt mixture in which at least a portion of the starting material is recycled asphalt.
preparing at least two grades of aggregate; transferring a metered amount of scrap material to one dryer for drying and heating the aggregate; and drying in separate holding compartments according to one grade. and sieving the heated aggregate and providing a source of recycled asphalt of suitable consistency; such that heat transport is allowed between the dried and heated aggregate and the recycled asphalt. transporting the recycled asphalt to a regenerated material retention compartment that is physically separated but arranged in a heat transport relationship with at least one similar material retention compartment; Discharging aggregate and recycled asphalt from a holding compartment to mix the aggregate and recycled asphalt together; and adding bitumen to the at least partially mixed aggregate and asphalt.

Filler materials may be added as needed.

The screened aggregate is subjected to some degree of pre-mixing within the regeneration retention compartment and is preferably directed into the regeneration retention compartment to provide heat transport between the bone phase and the asphalt. Bone phase is preferably transferred at the same rate as it was fed to the sieve stage.

Also provided in accordance with the invention is an apparatus 4 for use in such a manufacturing method, which apparatus comprises a batch tower having a plurality of aggregate holding compartments for holding preheated aggregate and recycled asphalt. a regenerated material retention compartment for retaining a regenerated material, the regenerated material retention compartment being in heat exchange relationship with at least one of the aggregate retention compartments such that during use of the apparatus, the preheated aggregate The structure is such that heat can flow from the asphalt to heat the reclaimed asphalt.

The apparatus may also include at least one cold feed hopper for storing starting aggregate. The production equipment includes multiple cold feed hoppers for storing aggregates of various sizes for use in producing the final mixture. One form of apparatus according to the invention may include six cold feed hoppers.

The apparatus preferably includes one aggregate dryer. To preheat and heat the aggregate 1 (may include a belt conveyor etc. to transfer the aggregate from the cold feed hopper to the dryer) 0 This belt conveyor ensures that the correct proportion of aggregate is transferred from each cold feed hopper It may be controlled by an automatic control system so that it is supplied.

The hot, dried aggregate may be conveyed to the batch column by transfer belts, elevators, or other suitable means.

The device may include a particle size sieve mechanism for separating the preheated and dried aggregate into various grades and a holding system for holding this sieved paulownia material. A sieving mechanism is provided to divide the aggregate into several particle size ranges in any suitable manner.

The holding stem may include one or more separate compartments for holding the sized and graded aggregate.

Each holding chamber is preferably provided with one aggregate holding tank.

This aggregate holding tank may be arranged in any convenient manner, preferably with the particle size sieve section being arranged in a straight line below the mechanism. In a variant embodiment, the aggregate holding compartment has one
provided as separate aggregate compartments within two holding tanks. Preferably, the osseous retention vessels or compartments are arranged in heat transfer relationship with each other so that heat transfer occurs between them and heat loss and temperature fluctuations are minimized.

The recycle holding compartment may be provided by one recycle holding tank or one recycle holding compartment of one aggregate holding tank. The regeneration retention compartment is positioned in heat transport relationship with at least one aggregate retention tank, preferably to receive optimal heat transport from the one or more aggregate retention tanks. This arrangement allows heat transport between the dried and heated aggregate and the recycled material held within the holding system.

Each holding tank may be equipped with one or more exit gates for discharging the held material. Preferably, the outlet gate of the recycled material holding tank is arranged to enhance the mixing of aggregate and recycled material. The outlet gate of the regeneration holding tank may be located between the exit gates of the aggregate holding tank.

Preferably, the apparatus of the present invention also includes one separate recycle feed hopper for storing recycled asphalt material to be recycled prior to its transfer to the recycle holding tank. The recycled material stored in this recycled feed hopper may be metered into the recycled holding tank as desired through an independent recycled belt feeding mechanism. is preferably controlled by the same automatic control system as is preferably used to control said belt feeding mechanism associated with the aggregate feed hopper.

Thereby, the ratio of aggregate and recycled material is adjusted as necessary.

The raw material is transported to the batch tower by a transfer belt or elevator. A conveyor belt is used to transport the recycle material from the recycle hopper to the appropriate holding compartment. The recycled material is preferably arranged to be charged approximately in the center of the recycled holding compartment or reservoir.

The equipment supplies either aggregate or recycled asphalt from the batch tower;
Alternatively, the receiver may include a weighing hopper for receiving both. The proportion of aggregate and recycled asphalt discharged from the holding tank into the weighing hopper may be controlled according to the grade of the mixture required for the final batch.

Bitumen may be added to the mixture from a suitable bitumen storage tank or other facility. It is preferable that the addition of bityumen be carried out in a suitable mixing chamber. Fillers such as fine particulate materials or fine powders may also be added in this mixing chamber or elsewhere.

An associated fill tank or storage tower may be provided for this purpose. In a preferred 1tVC of the present invention, fine particles are extracted and recollected from the exhaust air of the aggregate dryer and used as at least a portion of the filler. This extraction is carried out, for example, by means of a bag filter.

According to yet another aspect of the invention, there is associated a regeneration holding compartment or tank and a switching gate 1. This switching gate is placed along the partition between the aggregate holding tank and the regeneration holding tank. Preferably, this switching gate runs along the entire length of the bulkhead.

In one form, the switching gate may be biased to draw at least a portion of the aggregate into the recycle holding tank.

A premix is carried out on both sides to allow the aggregate to enter the regeneration holding tank.・The extent of mixing and heat transport is determined by the speed of the belt conveyor supplying the recycled paulownia material and/or the position of the switching gate. In one form, the switching gate may be located on the underside of the sizing sieve. Preferably the switching gate is located across the length of the sizing sieve. Preferably, the switching gate is suitable for drawing aggregate into the regeneration holding tank at the rate fed to the screen by the hot elevator.

Preferably, the amount of aggregate directed into the regeneration holding tank is a function of the location of the switching point.
+JJ exchange gate, in one form, is arranged so that, for example, 0 to 30% of the incoming old material is directed to the regenerated material holding tank.
This amount depends on the (nit K) of the gate. The position of the 9J exchange gate can be set by adjusting a manual stop.

The switching gate is preferably pneumatically driven from a control station.

The proportion of aggregate entering the regeneration holding tank can thus be adjusted by selecting the position of the corresponding gate stop. The proportion of recycle that enters the recycle holding tank is selected by the speed of the belt feeder and the size of the opening of the discharge gate of the recycle supply hole. Typically, the aggregate feeder is driven to the recycled material feeder at the correct feed rate so that the mixture in the recycled holding tank has the correct parameters for mixing and composition materials. .

The belt feeder preferably operates on a precalibrated volumetric basis that does not vary with moisture content.

Preferably, a load cell is provided on the recycle transfer belt to indicate the presence of recycle material. This makes it possible to provide the operator of the device with information as to when the switching gate is actuated to initiate the simultaneous flow of recycled material and aggregate into the recycled material holding compartment.

If recycling is not required, a single switching chute may be provided at the end of the sizing sieve to direct the phase half passing over the top bed into the regeneration holding tank, which allows the coarse mixture to be mixed with all new material. The regeneration tank is the largest material i-1
Can be used as a tank.

The manufacturing method and equipment described above provides flexibility in the rate of recycled material that can be fed through the asphalt production/stem. This manufacturing method allows time for heat transport between the recycled material and the raw material 4J and can be set and adjusted accordingly according to the appropriate mixing scheme.

Since the recycled material is graded and introduced into the asphalt production process, clogging of the classification screen by sticky recycled 4S is avoided.

The temperature of the mixture may be stabilized and homogenized due to gradual heat transport or "heat osmosis" during the holding stage, which is further progressed during the premixing and mixing stages.As a result, the temperature of the final mixture will be lower than that of the final mixer. The temperature in the final mixture gradually stabilizes during the manufacturing process, so the dryer is operated at a low temperature to reduce the amount of water between aggregate and recycled material. Make it possible to transport heat.

As a result, maintenance costs and energy consumption are considerably reduced.

Preferred embodiments of the asphalt recycling system according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawings.

Referring to the drawing, six cold feed hoppers are shown for storing unused scrap material at 10°C.

The aggregate is precisely metered by a corresponding belt feeder 11 with a variable speed drive adjustable by an automatic feedback control system (not shown).

The transport belt 12 transports the aggregate to the dryer 13.

The dried hot aggregate is conveyed by a hot elevator 14 to a particle size separating screen 15 of the batch column. This batch column includes four holding tanks 16 for holding the classified aggregate after passing through the particle size l-1' screen 15.

A fifth holding tank 18 is juxtaposed to holding tank 16 and receives recycled material. Recycled material is fed from a separate feed hopper 19 and metered into the system via a belt feeder 20. The regeneration feeder 20 is automatically controlled in exact proportion to the aggregate feeder.

A switching gate 22 is provided across the partition wall 2:3 between the holding tanks 16 and 18. The diverter cage 22 is operated by an aerodynamic control system (not shown) to direct 0 to 30 inches or more of the incoming aggregate into a holding tank as required. is positioned.

When the above-mentioned reuse is not carried out, a switching chute (not shown) is attached to the grain size dividing bath 15° C. to direct the rough material O1 into the holding tank J8.

Holding tanks 16 and 18 have an fE generally designated by the number 24.
, with several exit gates. The material is discharged into the weighing hopper 25 via the exit gate.

Finally, the bitumen and fillers used are added to the material prior to mixing and discharged for transport.

[Brief explanation of the drawing]

The attached drawings are diagrams showing an embodiment of the asphalt mixture manufacturing apparatus according to the present invention. %W + 1iX people Mobile Oil Association Corp. Rayon (outside 4 people)

Claims (1)

[Claims] 1. In a method for producing an asphalt mixture in which at least a part of the starting material is recycled asphalt: at least 1
preparing two grades of aggregate; transferring the metered quantities of aggregate to a dryer for drying and heating the aggregate; and the step of sifting the aggregate. preparing a source of recycled asphalt of consistency if; placing the reclaimed asphalt in physically separated but heat transporting relationship with the at least one aggregate holding compartment such that heat transport is permitted between the dried and heated aggregate and the reclaimed asphalt; transporting the aggregate and recycled asphalt from the plurality of retention compartments to at least partially mix the bone phase and the recycled asphalt; A method for producing an asphalt mixture, comprising: adding bitumen to partially mixed aggregate and recycled asphalt. 2. The manufacturing method according to claim 1, which includes the step of finally mixing aggregate, recycled asphalt, and bitumen. 3. In the manufacturing method described in claim 1 or 2, a part of the sieved aggregate is recycled and retained in order to perform pre-mixing and heat transport to a predetermined degree. The method of manufacturing comprises the step of directing the compartment. 4. An apparatus for producing asphalt mixtures in which at least a portion of the starting material is recycled asphalt, with a batch tower having a plurality of counterfeit holding compartments for holding preheated aggregate and a recycled asphalt for holding recycled asphalt. a retention compartment, the regeneration retention compartment being in heat exchange relationship with at least one of the aggregate retention compartments to heat the recycled asphalt with the preheated aggregate during use of the apparatus. An asphalt mixture manufacturing device characterized in that it is configured so that heat flows therethrough. 5. The manufacturing apparatus as set forth in claim 4, wherein the batch column further comprises a sieve for separating the preheated aggregate into an aggregate holding compartment selected according to the size of the aggregate. The device comprises means. 6. The manufacturing apparatus according to claim 5, wherein the sieving means comprises one particle size classification screen located above the plurality of material holding compartments. 7. A manufacturing device according to any one of claims 4 to 6, wherein each holding compartment is provided with at least one exit gate for discharging the held material. . 8. In the manufacturing apparatus according to any one of claims 4 to 7, a switching gate that can be biased to draw at least a portion of the aggregate into the regenerated material holding compartment is provided in the regenerated material holding compartment. The device is incorporated into a chamber. 9. A manufacturing apparatus according to any one of claims 4 to 8, comprising a weighing hopper for receiving aggregate and recycled asphalt from the holding compartment. 10 A mixing chamber for receiving scrap materials and recycled asphalt from a holding compartment chamber or a weighing hopper, respectively, at a temperature of °C in the manufacturing apparatus described in any of claims 4 to 9. 11. The manufacturing apparatus according to any one of claims 4 to 10, comprising means for adjusting the supply of recycled asphalt in proportion to the aggregate. The said device.