Method for extracting exhaust gases during loading of hot asphalt from an asphalt production plant

Abstract

The invention relates to a method for extracting exhaust gases during loading of hot asphalt from an asphalt production plant (1) onto a transport vehicle (2). The ready-for-use hot asphalt is provided in asphalt preparation silos (3a, 3b, 3c) and loaded onto the transport vehicle (2) arranged thereunder. The asphalt preparation silos (3a, 3b, 3c) are arranged inside a hood (4) that is closed at the top and open at the bottom, in such a way that there is a gap (12) between the inner boundaries of the hood (4) and the asphalt preparation silos (3a, 3b, 3c) which substantially extends around said silos and which connects the open lower end (U) of the hood (4) to the closed upper end (O) of the hood (4). During the loading of the hot asphalt onto the transport vehicle (2), a vacuum is generated at the upper end (O) of the hood (4), so that exhaust gases emanating from the hot asphalt in the loading region and any exhaust gases emanating from the asphalt preparation silos (3a, 3b, 3c) are transported to the upper end of the hood (4) and extracted there. By means of the invention, it is possible to extract practically all exhaust gases arising during the preparation and loading of the hot asphalt in concentrated form and to direct them to a targeted disposal. A further advantage obtained is the fact that the amount of extracted contaminated air can be reduced to a fraction of the amount of contaminated air resulting from the prior art, which makes the subsequent treatment and / or disposal significantly more cost-effective.

Description

[0001] Method for extracting exhaust gases when loading hot asphalt from an asphalt production plant

[0002] TECHNICAL FIELD

[0003] The invention relates to a method for extracting exhaust gases when loading hot asphalt from an asphalt production plant onto a transport vehicle and to an asphalt production plant for carrying out the method according to the preambles of the independent patent claims.

[0004] STATE OF THE ART

[0005] When hot asphalt is loaded from an asphalt production plant onto a transport vehicle, foul-smelling exhaust fumes and pollutants (blue smoke) are released, which often leads to complaints from authorities and people in the vicinity of such plants.

[0006] To reduce these emissions, existing plants today extract a portion of the exhaust gases released using extraction pipes located in the loading area. Aside from the fact that this requires extracting vast amounts of air from the loading area and then disposing of / treating it, this process consumes a great deal of energy and is ultimately unsatisfactory because a large portion of the exhaust gases still escapes into the environment.

[0007] PRESENTATION OF THE INVENTION

[0008] The task here is to provide technical solutions which do not have the aforementioned disadvantages of the state of the art or at least partially avoid them.

[0009] This problem is solved by the subject-matter of the independent patent claims.

[0010] According to these, a first aspect of the invention relates to a method for extracting exhaust gases when loading hot asphalt from an asphalt production plant (often also referred to as an "asphalt mixing plant") onto a transport vehicle.

[0011] The hot asphalt to be loaded is prepared in one or more asphalt preparation silos (often referred to as "mix silos") and loaded onto a transport vehicle located below by means of gravity conveying.

[0012] The asphalt supply silos are arranged within a hood that is closed at the top and open at the bottom, such that between the inner boundaries of the hood and the asphalt supply silos there is or are one or more gaps that connect the open lower end of the hood to the closed upper end of the hood. Support webs and / or air deflectors extending essentially in a vertical direction can be provided in this gap or these gaps.

[0013] In a preferred embodiment of the method, the gap is a gap that essentially runs around the asphalt supply silos.

[0014] At least during loading of the hot asphalt onto the transport vehicle, a vacuum is created at the upper end of the hood, so that exhaust gases emanating from the hot asphalt in the loading area and any exhaust gases emanating from the asphalt supply silos, possibly assisted by their thermal buoyancy, are transported to the upper end of the hood and extracted there. Thus, a flow is created around the asphalt supply silos, by means of which the exhaust gases from the loading area and any exhaust gases emanating from the silos are transported away.

[0015] The invention makes it possible to extract virtually all of the exhaust gases generated during the preparation and loading of hot asphalt in concentrated form and direct them for targeted disposal. Another advantage is that the extracted contaminated air volumes can be reduced to a fraction of the contaminated air volumes resulting from the prior art, making their post-treatment / disposal significantly more cost-effective. For example, it is possible to feed the entire extracted air volume to a burner in a drying drum of the asphalt production plant and subject it to thermal post-treatment there.

[0016] In a preferred embodiment of the method, the asphalt supply silo(s) is / are fed with hot asphalt using a mobile bucket. The transfer of the hot asphalt from the mobile bucket to the at least one asphalt supply silo also takes place within the hood.

[0017] If the truck bucket is fed with hot asphalt from an asphalt mixer, which is usual, it is preferable that the transfer of the hot asphalt from the asphalt mixer to the truck bucket also takes place inside the hood.

[0018] This makes it possible to extract the exhaust gases that arise in the transfer zones from the asphalt mixer to the mobile bucket and from the mobile bucket to the asphalt supply silos(s) completely and in concentrated form and to dispose of them.

[0019] Advantageously, the extracted exhaust gases are used entirely or at least partially as combustion air for a burner in the asphalt production plant to heat material to form the hot asphalt to be produced, for example, as combustion air for a burner in a drying drum to heat white mineral material. In this way, treatment / disposal by thermal post-treatment can be realized with minimal plant-related expenditure.

[0020] Before being used as combustion air, the extracted exhaust gases are subjected to a treatment to remove moisture and hydrocarbons, and / or filtered to remove dust particles and fine droplets.

[0021] A second aspect of the invention relates to an asphalt production plant (asphalt mixing plant) for carrying out the method according to the first aspect of the invention.

[0022] The plant comprises one or more asphalt preparation silos (mix silos) for preparing ready-to-install hot asphalt for loading onto a transport vehicle.

[0023] The asphalt supply silos are arranged within a hood that is closed at the top and open at the bottom, such that between the inner boundaries of the hood and the asphalt supply silos there is or are one or more gaps that connect the open lower end of the hood to the closed upper end of the hood. Support webs and / or air deflectors extending essentially in a vertical direction can be provided in this gap or these gaps.

[0024] In a preferred embodiment of the plant, the gap is a gap that essentially runs around the asphalt supply silos.

[0025] The asphalt production plant according to the invention further comprises an extraction system by means of which a vacuum can be created at the upper end of the hood, at least while the hot asphalt is being loaded onto the transport vehicle, so that exhaust gases emanating from the hot asphalt in the loading area and any exhaust gases emanating from the asphalt preparation silos, optionally assisted by their thermal buoyancy, can be transported to the upper end of the hood and extracted there. In this way, a flow can be created around the asphalt preparation silos, by means of which the exhaust gases from the loading zone and any exhaust gases emanating from the silos are transported away. The hood advantageously widens out in a funnel shape at its lower end so that exhaust gases rising in the area around the actual loading zone can also flow into the hood.

[0026] The system preferably comprises a mobile hopper with which the asphalt supply silo(s) can be fed with hot asphalt. The system is designed such that the transfer of hot asphalt from the mobile hopper to the respective asphalt supply silo can take place within the hood. This is advantageously realized such that the mobile hopper is arranged within the hood and can be moved exclusively within the hood.

[0027] It is further preferred that the system comprises an asphalt mixer, with which the mobile hopper can be fed with hot asphalt. The system is designed such that the transfer of hot asphalt from the asphalt mixer to the mobile hopper can take place inside the hood. This is advantageously realized such that the discharge opening of the asphalt mixer opens into the interior of the hood, while the mixer itself, or at least its feeding devices, are arranged outside the hood.

[0028] This makes it possible to extract the exhaust gases that arise in the transfer zones from the asphalt mixer to the mobile bucket and from the mobile bucket to the asphalt supply silos(s) completely and in concentrated form and to dispose of them.

[0029] In a further preferred embodiment, the plant comprises a burner for heating material used to form the hot asphalt to be produced by the plant. This can be, for example, the burner of a drying drum for heating white mineral material or recycled asphalt material. The plant is designed such that the extracted exhaust gases can be used entirely or at least partially as combustion air for the burner. In this way, treatment / disposal of these exhaust gases by thermal aftertreatment can be achieved with little plant-technical outlay.

[0030] The system advantageously comprises devices with which the extracted exhaust gases can be treated before they are used as combustion air for the burner, in order to separate moisture and hydrocarbons and / or dust particles and fine droplets.

[0031] BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Further embodiments, advantages, and applications of the invention will become apparent from the dependent claims and the following description with reference to the figures. In these figures:

[0033] Fig. 1 is a highly abstracted front view of an asphalt production plant according to the state of the art;

[0034] Fig. 2 is a view similar to Fig. 1 of an asphalt production plant according to the invention; and

[0035] Fig. 3 shows the layout of the asphalt production plant from Fig. 2.

[0036] WAYS OF IMPLEMENTING THE INVENTION

[0037] Fig. 1 shows in a highly abstract form a front view of an asphalt production plant 1 according to the prior art.

[0038] As can be seen, the system 1 comprises several asphalt supply silos 3a, 3b, 3c arranged next to one another for providing hot asphalt ready for installation for loading onto a transport vehicle 2 arranged underneath.

[0039] A mobile hopper 5 is arranged above the asphalt supply silos 3a, 3b, 3c, which is used to charge the individual asphalt supply silos 3a, 3b, 3c with hot asphalt in batches. The mobile hopper 5, in turn, receives the hot asphalt from an asphalt mixer 6 arranged above it. The asphalt material flows from the asphalt mixer 6 into the mobile hopper 5, from the mobile hopper 5 into the asphalt supply silos 3a, 3b, 3c, and from the asphalt supply silos 3a, 3b, 3c to the transport vehicle 2 are represented by thick arrows. With each transfer of the hot asphalt material, exhaust gases are released, which are represented by thin arrows.

[0040] The exhaust gases released during loading onto the transport vehicle 2 are partially extracted by means of an extraction device 10 via extraction pipes 11 arranged in the loading zone. The exhaust gases released during transfer from the asphalt mixer 6 to the mobile bucket and from the mobile bucket 5 to the asphalt supply silos 3a, 3b, 3c, however, are released into the environment, as is the non-extracted portion of the exhaust gases released during loading onto the transport vehicle 2.

[0041] Fig. 2 shows, in a highly abstract form, a front view of an asphalt production plant 1 according to the invention, which has an identical structure to the plant according to Fig. 1 with regard to the main plant components (asphalt supply silos 3a, 3b, 3c, mobile bucket 5 and asphalt mixer 6). Instead of the suction pipes 11 in the area of ​​the loading zone, the plant 1 according to the invention, however, has a hood 4 which is closed at the top and open at the bottom and within which the asphalt supply silos 3a, 3b, 3c and the mobile bucket 5 are arranged. The asphalt mixer 6 is located outside the hood 4 and opens with its discharge opening from above into the space formed by the hood 4.Between the inner boundaries of the hood 4 and the asphalt supply silos 3a, 3b, 3c, there is a gap 12 that essentially surrounds the asphalt supply silos and connects the open lower end of the hood 4 with the closed upper end of the hood 4. Support webs and / or air deflectors extending essentially in a vertical direction can be provided in this gap 12.

[0042] At its lower end U, the hood 4 widens out in a funnel shape. At its upper end O, an extraction opening is arranged, via which, at least during loading of the hot asphalt onto the transport vehicle, a negative pressure is generated at the upper end O of the hood 4 by means of the extraction device 10, so that the exhaust gases emanating from the hot asphalt in the loading area as well as all other exhaust gases released in the hood 4, additionally supported by their thermal buoyancy, are transported to the upper end O of the hood 4 and extracted there.

[0043] As can be seen in conjunction with Fig. 3, which shows the plant diagram of the asphalt production plant according to the invention from Fig. 2, the air extracted from the hood 4 and contaminated with the exhaust gases is treated in a separation unit 9, whereby the moisture and hydrocarbons carried therein as well as dust and fine droplets are separated out. These are collected in a tank 13 and disposed of. The exhaust air from the hood 4, pre-cleaned in this way, is then optionally fed as combustion air to the burner 7 of the white mineral drying drum 8 of plant 1 or passed into the atmosphere via the raw gas filter system 14 of the drying drum 8 and the associated chimney system 15.

[0044] As can be seen in Fig. 3, the plant 1 has a total of six asphalt supply silos 3a-f arranged within the hood 4, which are fed with hot asphalt material via the mobile bucket 5.

[0045] While preferred embodiments of the invention are described in the present application, it is to be clearly understood that the invention is not limited thereto and may be embodied in other ways within the scope of the following claims.

Claims

PATENT CLAIMS 1. A method for extracting exhaust gases when loading hot asphalt from an asphalt production plant (1) onto a transport vehicle (2), comprising the steps of: a) Providing hot asphalt ready for installation in at least one asphalt supply silo (3a, 3b, 3c) which is arranged within a hood (4) which is closed at the top and open at the bottom in such a way that a gap is formed between the inner boundaries of the hood (4) and the at least one asphalt supply silo (3a, 3b, 3c) (12) or several gaps are formed, which connect or connect the open lower end (U) of the hood with the closed upper end (O) of the hood (4), b) arranging a transport vehicle (2) under the at least one asphalt supply silo (3a, 3b, 3c), c) loading hot asphalt by means of gravity conveying from the at least one asphalt supply silo (3a, 3b, 3c) onto the transport vehicle (2), wherein at least during the loading of the hot asphalt onto the transport vehicle (2) a negative pressure is created at the upper end (O) of the hood (4) so that exhaust gases emanating from the hot asphalt in the introduction area and any exhaust gases emanating from the at least one asphalt supply silo (3a, 3b, 3c) are transported to the upper end of the hood (4) and sucked off there.

2. The method according to claim 1, wherein the gap (12) a substantially at least one asphalt Provision silo (3a, 3b, 3c) circumferential gap (12) is .

3. Method according to one of the preceding claims, wherein the at least one asphalt supply silo (3a, 3b, 3c) is supplied with hot asphalt using a mobile bucket (5), the transfer of the hot asphalt from the mobile bucket (5) to the at least one asphalt supply silo (3a, 3b, 3c) taking place within the hood (4).

4. Method according to claim 3, wherein the mobile bucket (5) is fed with hot asphalt from an asphalt mixer (6), wherein the transfer of the hot asphalt from the asphalt mixer (6) into the mobile bucket (5) takes place inside the hood (4).

5. Method according to one of the preceding claims, wherein the extracted exhaust gases are used at least partially as combustion air for a burner (7) of the asphalt production plant (1) for heating material to form hot asphalt to be produced, in particular as combustion air for a burner (7) of a drying drum (8) for heating white mineral material or recycled asphalt material.

6. A method according to claim 5, wherein the extracted exhaust gases are treated to remove moisture and hydrocarbons before being used as combustion air for the burner (7).

7. Method according to one of claims 5 to 6, wherein the extracted exhaust gases are filtered before being used as combustion air for the burner (7) in order to separate dust particles and / or fine droplets.

8. Asphalt production plant (1) for carrying out the method according to one of the preceding claims, comprising a) at least one asphalt supply silo (3a, 3b, 3c) for providing hot asphalt ready for paving for loading onto a transport vehicle (2), wherein the at least one asphalt supply silo (3a, 3b, 3c) is arranged within a hood (4) which is closed at the top and open at the bottom in such a way that a gap (12) or several gaps are formed between the inner boundaries of the hood (4) and the at least one asphalt supply silo (3a, 3b, 3c), which gap or gaps connect or connect the open lower end (U) of the hood with the closed upper end (O) of the hood (4), and b) an extraction system (10), by means of which at least during the loading of hot asphalt from the at least one asphalt supply silo (3a, 3b,3c) a negative pressure can be generated on a transport vehicle (2) at the upper end (0) of the hood (4), so that exhaust gases emanating from the hot asphalt in the loading zone and any exhaust gases emanating from the at least one asphalt supply silo (3a, 3b, 3c) can be transported to the upper end (0) of the hood (4) and extracted there.

9. Plant according to claim 8, wherein the gap (12) a gap (12) essentially surrounding the at least one asphalt supply silo (3a, 3b, 3c) is 10. System according to one of claims 8 to 9, wherein the hood (4) widens in a funnel shape at the lower end (U).

11. Plant according to one of claims 8 to 10, wherein the plant comprises a mobile bucket (5) with which the at least one asphalt supply silo (3a, 3b, 3c) can be supplied with hot asphalt, and wherein the plant (1) is designed such that the transfer of the hot asphalt from the mobile bucket (5) to the at least one asphalt supply silo (3a, 3b, 3c) can take place within the hood (4).

12. Plant according to one of claims 8 to 11, wherein the plant comprises an asphalt mixer (6) with which the mobile bucket (5) can be charged with hot asphalt, and wherein the plant (1) is designed such that the transfer of the hot asphalt from the asphalt mixer (6) into the mobile bucket (5) can take place inside the hood (4).

13. Plant according to one of claims 8 to 12, wherein the plant comprises a burner (7) for heating material to form hot asphalt to be produced, in particular a burner (7) of a drying drum (8) for heating white mineral material or recycled asphalt material, and wherein the plant is designed such that the extracted exhaust gases can be used at least partially as combustion air for the burner (7).

14. Plant according to claim 13, wherein the plant comprises a device (9) for treating the extracted exhaust gases before their use as combustion air for the burner (7) for the purpose of separating moisture and hydrocarbons.

15. Plant according to one of claims 8 to 14, wherein the plant comprises a device (9) for filtering the extracted exhaust gases before their use as combustion 5 air for the burner (7) for the purpose of separating dust particles and / or fine droplets.

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