WO2017015768A1

WO2017015768A1 - Method for producing asphalt by using granular recycled asphalt material

Info

Publication number: WO2017015768A1
Application number: PCT/CH2015/000111
Authority: WO
Inventors: Jan THOMSCHKE; Oliver Hahn; Axel Nagel
Original assignee: Ammann Schweiz Ag
Priority date: 2015-07-28
Filing date: 2015-07-28
Publication date: 2017-02-02
Also published as: CH712358B1; DE112015006301A5

Abstract

The invention relates to a method for producing asphalt by using granular recycled asphalt material. In the method, the granular recycled asphalt material is fed to the drum (1) of a drum dryer and passed through the drum (1) while it is rotating, and is thereby heated by a stream of hot gas (H), which enters the drum (1) at a first drum end (B) and leaves the drum (1) at a second drum end (A). According to the invention, mineral dust particles ("filler") are fed into the drum (1) in such a way that the inner wall and internal components of the drum (1) in the region of the second drum end (A) are covered with dust particles. It has been found that this allows the tendency for recycled asphalt material to become baked on in the drum (1) to be reduced significantly. Furthermore, in the case of most asphalt formulations, a certain filler content is an essential component of the ready-to-lay asphalt, and so the addition of the dust particles does not have any detrimental effect on the quality of the asphalt.

Description

Process for the production of asphalt using granular recycling asphalt material

TECHNICAL AREA

The invention relates to a process for the preparation of asphalt ^¬ position using granulatförmi ^¬ according recycling asphalt material, a drum dryer for use in the process and the use of the drum dryer for the production of asphalt according to the preambles of the independent claims.

STATE OF THE ART

In systems for the drying and heating of granular mineral and / or recycled asphalt material for the production of asphalt Drummeltrock ^¬ ner with slightly inclined, rotating drying drums are used, in which a material curtain is formed from the granular material, which of a hot - Gas flow is interspersed. Here, the to trock ^¬ designating and material to be heated passes through the drying drum in the same direction as the hot gas flow (direct drum dryer) or in an opposite direction as the hot gas flow (counterflow drum dryer). The hot gas flow is provided by a mostly fired with fossil fuel ^¬ materials such as natural gas, fuel oil or coal dust hot gas generator.

In operation results in recycling asphalt ^¬ material the problem is that the bitumen content in recy- clingasphaltmaterial whose weight percentage is in the gan ^¬ Gigen asphalt formulations at 3% to 8%, in the temperature ^¬ turbereich between 90 ° C and 120 ° C softened and sticky becomes (transition from solid to liquid state) resulting in the recycled asphalt material in counter drum dryers in the area of the material feed end of the drum and in DC tumble driers in the drum Area of the dispensing end of the drum tends to adhere to the walls and internals of the drum. The greater the bitumen content in recycled asphalt material, the more pronounced this problem is. Accordingly, it is not possible with today's drum dryers to process large amounts of recycled asphalt material without caking occur.

PRESENTATION OF THE INVENTION

It is therefore an object to provide methods and devices that do not have the aforementioned disadvantages of the prior art or at least partially avoided.

This object is solved by the subject matters of the independent claims.

According to these, a first aspect of the

The invention relates to a process for the production of asphalt using granular recycling asphalt material.

In the method, the granular recycled asphalt material is fed into the drum of a drum dryer and passed through a rotation of the drum and thereby from a stream of hot gas, which enters the drum at a first end of the drum and emerges from the drum at a second end of the drum , heated. The process can be carried out with 100% recycled asphalt material as well as with a proportion of recycled asphalt material and a proportion of virgin mineral material.

According to the invention mineral dust particles, preferably mineral matter (also known as "filler") is fed into the drum, the ^¬ art that the inner wall of the drum in the region of the second drum end, ie drum end at which the hot gas stream exiting from the drum, with Dust particles is occupied.

It has been shown that this causes the

Tendency to bake recycled asphalt mate than in the Drum can be significantly reduced. In addition, a certain amount of filler in most asphalt formulations zwin ^¬ gender component of the ready-to-install asphalt, so that the addition of dust particles has no detrimental effect on the asphalt quality.

In a preferred embodiment of the process, only recycled asphalt material is supplied to the drum, i. The drum dryer is driven with 100% recycled asphalt material.

If it is desired not to provide the mineral content solely through the recycled asphalt material, but also to use some level of virgin mineral material, according to another preferred embodiment of the process, this may be passed through the same drying drum and heated together with the recycled asphalt material , This has the advantage that it is possible to dispense with a separate drying drum and the investment and maintenance costs for the asphalt production plant can be significantly reduced.

In a further preferred embodiment of the method, the dust particles are fed into the drum separately from the recycled asphalt material and / or the new mineral material. This makes it possible the amount and fed ^¬ led the feeding location precisely controlled.

In this case, it is further preferred to inject the dust particles into the drum, preferably into a zone in the region of the claimed second drum end (ie the drum end at which the hot gas stream leaves the drum), preferably into an area in which the binder of the drum subsidized recycling asphalt material has a temperature of less than or equal to 120 ° C. By blowing las ^¬ sen to the dust particles targeted lead into the wall areas of the drum.

The blowing is advantageously carried out via one or more axially projecting into the drum Einblase- lances, which preferably project from the claimed second drum end into the drum. Such devices for injecting the dust particles are inexpensive and easy to manufacture and do not require significant maintenance.

Preferably, exactly one central injection lance is used. As a result, the associated obstruction of the passage cross section of the drying drum can be kept as low as possible.

Further, it is preferred if the process is a continuous process in which the recycled asphalt material and optionally the virgin mineral material are continuously fed into the drum dryer.

The feeding of the dust particles in the Trom ^¬ mel can be continuous or intermittent, insbesonde re ^¬ at regular intervals. Depending on the system concept, the one or the other variant may be before ^¬ ferred.

Advantageously, the drum dryer used in the process is part of a contiguous asphalt production plant, wherein all of the supplied dust particles or at least a majority of the supplied dust particles are collected in this asphalt production plant (for example in the filter). This results in the advantage that the dust particles accumulating in the system can be recycled and no "foreign filler" or only so much "foreign filler" must be purchased as is necessary in order to work together with the "Autologous" to ensure proper operation and, where appropriate, the maintenance of asphalt formulation.

Advantageously, a counter-current drum dryer or a DC drum dryer is used for carrying out the method according to the invention. Countercurrent drum dryers typically allow one Gentler heating of recycled asphalt material as a DC drum dryer.

A second aspect of the invention relates to a drum dryer for carrying out the method according to the first aspect of the invention. The dryer comprises a drying drum, through which the recycling asphalt material and optionally the additional virgin material are conveyed under rotation of the drum during normal operation and thereby heated by a stream of hot gas entering and leaving the drum at a first end of the drum a second end of the drum emerges from the drum. Next environmentally summarizes the drum dryer means for feeding dust particles, preferably fine particles (also known as "filler") in the drum, such that the inner wall of the drum in the region of the second drum ^¬ end, ie drum end at which the hot gas stream from the Drum emerges, is covered with dust particles.

It has been found that this can significantly reduce the tendency for baking the recycled asphalt material in the drum. Even a limited hours ^¬ ter filler content in most asphalt formulations is zwin ^¬ gender component of the pre-finished asphalt, so the addition of dust particles has no detrimental effect on the asphalt quality.

Advantageously, the devices are to to ^¬ result of dust particles formed for blowing the dust particles in the drum of the drum dryer, namely preferably into a zone in the region of the second drum end aforesaid, preferably in a region in which in normal operation, the binder of the by Drum of the drum dryer funded recycled asphalt material has a temperature less than or equal to 120 ° C. In this zone, the tendency to caking of the material to the inner wall of the drum is typically particularly large. Such devices for injecting the dust particles preferably comprise one or more injection lances axially projecting into the drum, which advantageously project from the second drum end according to the claims into the drum. Such devices for injecting the dust particles are inexpensive and easy to manufacture and do not require significant maintenance.

Preferably, the drum drier right on a central Einblaselanze for injecting fuel ^¬ ler into the drum. As a result, the associated obstruction of the passage cross section of the drying drum can be kept as low as possible.

In a further preferred embodiment of the drum dryer, its drum is in the region of the second end of the drum, i. of the drum end at which the hot gas stream exits the drum, a non-metallic lining.

It has been found that this can further reduce the tendency for the recycling asphalt material to cake in the drum.

If the non-metallic lining is made of a material which has a thermal conductivity of less than 10 W / mK in a temperature range between 70 ° C. and 170 ° C., preferably less than 5 W / mK and even more preferably less than 1 W / mK, then a significant additional reduction of adhesion tendency can be achieved.

Has the surface of the non-metallic lining in normal operation at surface temperatures between 90 ° C and 120 ° C lower adhesion ability for bitumen than a corresponding ^¬ de (ie gleichgeformte and roughened by the intended contact with the material) steel surface in normal operation at these temperatures, which is preferred, the tendency to cake the recycled asphalt material is further reduced. In a first variant, the non-metallic ^¬ metallic lining of the drum is formed by a non-metalli ^¬ specific coating on one or more metallic or ceramic components. This results in the advantage that the actual supporting structure of the lining can be formed from a different material, for example made of cast iron, which depending on the design can save costs. It is also possible, by re-coating worn components to "reconditioning" and thereby supply a new life cycle.

The non-metallic coating may be playing, a ceramic coating at ^¬, insbeson ^¬ particular of titanium carbide, or a plastic coating, in particular made of PTFE, PEEK or of a ketone.

Such materials are particularly well suited for this purpose.

In another variant, the non-metallic lining of the drum is formed by one or more components of a ceramic material or of a plastic material, preferably of PTFE, of PEEK or of a ketone. The components thus consist of the material forming the lining. Such embodiments have the advantage that a long service life of the non-metallic lining is possible, since a replacement of the components forming them only becomes necessary when the wear is so great that the component strength is no longer guaranteed. ^'

Advantageously, the drum dryer is designed as a countercurrent drum dryer or as a DC drum dryer. Counterflow drum dryers have the advantage that they typically allow for a more gentle heating of the recycled asphalt material than do DC tumble dryers.

A third aspect of the invention relates to the use of such a countercurrent drum dryer or A DC tumble dryer according to the second aspect of the invention for drying and heating granular new mineral material and / or recycled asphalt material for asphalt production.

BRIEF DESCRIPTION OF THE DRAWINGS

Further embodiments, advantages and applications of the invention will become apparent from the dependent claims and from the following description with reference to FIGS. Showing:

1 shows a longitudinal section through the drying drum of a DC tumble dryer according to the invention;

FIG. 2 shows a longitudinal section through the drying drum of a countercurrent drum dryer ^{according to the} invention; FIG. and

3 is a perspective sectional view through the task end of the drying drum of Fig. 2.

4 is a perspective sectional view through the task end of a variant of the drying drum of FIG. 2;

Fig. 5 shows the detail X of Fig. 4;

Fig. 6 shows the detail Y of Fig. 4; and

Fig. 7 shows a perspective cross-section through a part of the lining of the drum according to FIG. 4 in the region of the on abende.

WAYS FOR CARRYING OUT THE INVENTION

1 shows the drying drum 1 of a DC tumble dryer according to the invention for drying and heating granular Neu-Mineralmate ^¬ rial and / or recycled asphalt material for asphalt production in vertical longitudinal section.

As can be seen, the drum 1 is mounted with bearing rings 3 mounted on its outer circumference on bearing arrangements 3, via which they are guided in the particular case. according to the operation is set in rotation. It is slightly inclined to the right, so that the direction of passage L of the material during normal operation runs from the left (material inlet area EB) to the right (material outlet area AB).

The material to be dried and heated occurs at the end of loading B of the drum 1 (claims first drum end) via a material chute 4 in the inlet region EB of the drum 1, from where it by the rotation and inclination of the drum 1 to the discharge end A of the drum 1 (Fig. is conveyed according to the claims second end of the drum) toward and after being dried when passing through the drum 1, and heated again leaves the drum 1 in an off ^¬ overflow area AB. The hot ^¬ gas stream H, which producers of a fossil fuels such as natural gas, fuel oil or coal dust hot gas (not shown) is provided through ^¬ the drum 1 flows in the flow direction L of the material, ie from the end of task B of the drum 1 to the Dispensing end A of the drum 1. On the inner wall of the drum 1 as seen in the flow direction L after the inlet region EB approximately in the first third radiation plates 5 are arranged. In the remaining area are on the inner wall of the drum. 1

Blade rake 6 arranged, with which the material is raised during the rotation of the drum 1 and then dropped as a material curtain through the hot gas flow H therethrough.

As can be seen, projecting from the end of the delivery Ä the drum 1 a central Einblaselanze 8 in the Drom ^¬ mel 1 into which dust particles (filler) are blown into the drum 1 during normal operation, such that the inner wall and the surface of the Schaufelrechen 6 of the drum 1 are occupied in the region of this end of the drum A with dust particles.

2 shows the drying drum 1 of a countercurrent drum dryer according to the invention for drying and heating granular new mineral mats. Rial and / or recycled asphalt material for asphalt production in vertical longitudinal section.

As can be seen, the drum 1 mounted on its outer peripheral circular rings 2 on bearing assemblies (not shown) is mounted on wel ^¬ che it is rotated during its intended operation. It is slightly inclined to the right, so that the direction of passage L of the material during normal operation runs from the left (material inlet area EB) to the right (material outlet area AB).

The material to be dried and heated occurs at the task end A of the drum 1 (claims second drum end) via a material slide 4 in the inlet region EB of the drum 1, from where it by the rotation and inclination of the drum 1 to the discharge end B of the drum 1 (Fig. according to the claims the first end of the drum) toward ge promotes ^¬ is, and after being dried when passing through the Trom ^¬ mel 1 and heated, the drum 1 again leaves in an off ^¬ overflow area AB. The hot gas stream H, which producers of a fossil fuels such as natural gas, fuel oil or coal dust hot gas is provided (not shown) through ^¬ the drum 1 flows in the opposite direction to the direction L of the material, ie from the discharge end B of the drum 1 to the feed end A of the drum 1. on the inner wall of the drum 1 are ge ^¬ seen in the direction of passage L for the lead-in area EB blade rake 6 and scoop plates 7 are arranged just before the lead-out area AB in addition, with which raised the material during rotation of the drum 1 and is then dropped as a material curtain through the hot gas stream H therethrough.

As in particular in conjunction with FIG. 3 can be seen, showing a perspective Schnittdar ^¬ position by the charging end Ä of the drying drum 1 of FIG. 2, extends at the feed end A of this drum 1 is a central Einblaselanze 8 in the drum 1 into it, via which the intended operation dust particles (Filler) are blown into the drum 1, such that the inner wall of the drum 1 is covered in the region of this end of the drum A with dust particles.

FIG. 4 shows a representation like FIG. 3 of a variant of the drying drum 1 from FIG. 2. As can be seen, this variant of the drum 1 is in the region of its feed end A over its entire circumference with a PTFE sheet 9 of thickness 10 mm provided lining. The plates 9 are of the drum shape following arched and by means of their peripheral edges overarching fixed drum in the longitudinal direction and in the circumferential direction ver ^¬ continuous fastening strips 10, 11 on the drum inner wall.

As can be seen from Figures 5, 6 and 7, showing the details of X (Fig. 5) and Y (Fig. 6) of Fig. 4 and a perspective cross section of the PTFE lining of the drum 1 in the region of Aufgabeen ^¬ of A (Fig. 7) show, the plates 9 are in such a way fastened with the fastening strips 10, 11 on the drum inner wall, that their boundary edges in each case in which they receive, between the inner wall and the

Fixing strip 10, 11 formed gap 12 can move. In this way, the plates 9 can expand unhindered in the drum longitudinal ^direction and in the drum circumferential ^direction . In this case, the plates 9 are centered in each case at their peripherally extending boundary edges in the middle of a penetrating into this centering 13.

The drum 1 of Fig. 1 is provided in the same manner with a lining of PTFE plates in a before ^¬ ferred (not shown) embodiment, the region of its discharge end drum A.

While preferred embodiments of the invention are described in the present application, it should be clearly understood that the invention is not limited thereto and otherwise within the scope of the following claims can be executed.

Claims

1. A process for producing asphalt un ^¬ ter use of granular recycling asphalt material, comprising the steps of:

a) providing a drum dryer;

b) conveying the recycling asphalt material through the drum (1) of the drum dryer under a rotation of the drum (1);

c) heating the recycled asphalt material while passing through the drum (1) with a hot gas stream (H) which enters the drum (1) at a first drum end (B) and at a second drum end (A) from the drum (1) exit;

d) supplying dust particles, in particular fine dust, in the drum (1) such that the Innenwan ^¬ tion of the drum (1) in the region of the second end of the drum (A) is coated with dust particles.

2. The method of claim 1, wherein from ^¬ finally recycled asphalt material through the drum (1) of the drum dryer and heated with the hot gas stream (H).

3. The method of claim 1, wherein in addition to the recycling asphalt material granular Neu-Mineraimaterial through the drum (1) of the drum ^¬ drier fed and heated with the hot gas stream (H).

, Method according to one of the preceding claims, wherein the dust particles are supplied separately from the recycled asphalt material and / or the new mineral material in the drum (1).

5. The method of claim 4, wherein the

Dust particles are blown into the drum (1), in particular ^¬ in a zone in the region of the second end of the drum (A), in particular in a region in which the binder of the through the drum (1) funded Recyc- lingasphaltmaterials having a temperature less than or equal to 120 ° C.

6. The method of claim 5, wherein the blowing in via one or more axially into the drum (1) projecting Einblaselanzen · (8) takes place, which protrude in particular from the second end of the drum (A) in the drum (1).

7. The method of claim 6, wherein the blowing in via a single central blowing lance (8).

8. The method according to any one of the preceding claims An ^¬, wherein the recycled asphalt material and, optionally, the New-mineral material are continuously fed into the drum dryer.

9. The method according to any one of the preceding claims An ^¬, wherein the dust particles continuously into the drum (1) are fed.

10. The method according to any one of claims 1 to 8, wherein the dust particles intermittently into the drum (1) are fed, in particular at regular In ^¬ tervals.

11. The method according to any one of the preceding claims, wherein the drum dryer is part of a ^zusammen¬ hanging asphalt production plant and at least a part of the supplied dust particles collected in this Asphaltpro ^¬ production plant v / earth.

A method according to any one of the preceding claims, wherein a countercurrent tumble dryer is provided.

13. The method according to any one of claims 1 to 11, wherein a DC tumble dryer is provided.

14. Drum dryer for use in the method according to one of the preceding claims, comprising

a) a drum (1) through which the recycling asphalt material is used in the intended use and, if appropriate, the additional virgin mineral material is conveyed through a rotation of the drum (1) while being heated by a hot gas stream (H),

wherein the drum (1) has a first drum end (B), in which the hot gas stream (H) enters the drum (1) during normal operation, and has a second drum end (A) at which the hot gas flow (H ) emerges from the drum (1), and

b) means (8) for supplying dust particles, in particular fine dust, in the drum (1) such that the inner wall of the drum (1) in the region of the second end of the drum (A) is coated with dust particles.

15. drum dryer according to claim 14, wherein the means (8) for supplying the dust particles are adapted for blowing the dust particles in the drum (1) of the drum dryer, in particular in a zone in the region of the second end of the drum (A), in particular in a range in which in the normal operation, the binder of the funded through the drum (1) of the drum dryer recycled asphalt material has a temperature less than or equal to 120 ° C.

16. Drum dryer according to claim 15, wherein the means (8) for feeding the dust particles comprise one or more axially into the drum (1) projecting in ^¬ blaselanzen (8), which in particular from the second end of the drum (A) in the drum (1). protrude.

17. Drum dryer according to claim 16, wherein the means (8) for supplying the dust particles have a single central blowing lance (8).

18. Drum dryer according to one of claims 14 to 17, wherein the drum (1) of the drum dryer in the region of the second end of the drum (A) has a non-metallic lining (9).

19. Drum dryer according to claim 18, wherein the material of the non-metallic lining (9) in a temperature range between 70 ° C and 170 ° C has a thermal conductivity less than 10 W / mK, in particular less 5 W / mK, in particular less than 1 W / mK.

20. Drum dryer according to one of claims 18 to 19, wherein the surface of the non-metallic lining (9) at surface temperatures between 90 ° C and 120 ° C has a lower adhesion to bitumen than a corresponding steel surface at these temperatures.

Drum dryer according to one of claims 18 to 20, wherein the non-metallic lining (9) of one or more components (9) or coated with a ceramic material or from or coated with a KunstStoffmaterial, in particular PTFE, PEEK or a ketone , is formed.

The tumble dryer according to any one of claims 14 to 21, wherein the tumble dryer is a countercurrent tumble dryer.

23. Drum dryer according to one of claims 14 to 21, wherein the drum dryer is a DC drum dryer.

2. Use of the counterflow drum dryer according to claim 22 or the DC drum dryer according to claim 23 for drying and heating granular new mineral material and / or recycled asphalt material for asphalt production.