DE102014008947A1 - Apparatus and method for extracting binders from road building materials - Google Patents

Abstract

A device (10) for extracting binders from road building materials is proposed, having a wash-out device (12), characterized in that the wash-out device (12) has at least three modules (14, 20, 22) arranged one above the other, the modules (14, 20, 22) are designed as receiving cylinders, liquefied CO2 being used as flushing agent, and a method for extracting binders from road building materials, the CO2 being liquefied again by means of a compressor (36) and then serving again as a flushing agent.

Description

The invention relates to a device and a method for extracting binders from road building materials.

State of the art

Methods are known for self-monitoring of asphalt mix by road builders and control checks by extractions. Trichloroethene (TCE, C2HCl3) is the predominant solvent used in road construction laboratories for such methods of analysis. The extraction is carried out in particular with asphalt analyzers. In this case, solvent losses occur, with the solvents such as the said TCE escape into the environment. Therefore, it is desirable to replace the TCE in the asphaltene extraction by other solvents. Dichloromethane or 1,1,1-trichloroethane, for example, have been proposed for this purpose, but they each have considerable disadvantages with regard to toxicity or ozone killer action.

In particular, TCE solvents lead to CHC soil and groundwater contaminants. Upon contact with hot surfaces decomposition occurs to form u. a. Phosgene and chlorine. Comparable reaction products are produced by irradiation with UV light.

Toluene is also frequently used for binder recovery from road building materials and xylene for determining the water content of asphalt mixtures. However, these solvents are classified as neurotoxins.

Also known is the use of octene as a solvent for the asphaltene extraction. In this case, there is a surplus of water in the distillation circuit in a boiling vessel. The resulting water vapor conveys the octene to a condenser and returns with the solvent via the extraction material in the evaporator. The octene can be diverted to the condenser leaving water and bitumen in the boiling tank. However, the vapors of, for example, 1-octene can form an explosive mixture with air.

Furthermore, processes for the separation of asphalt mixtures and mineral solids by rinsing with a solvent from the abovementioned substances and subsequent evaporation of the solvent are known, wherein subsequently the asphalt fraction is present separately from the asphalt mixture.

A disadvantage of the known method is that the solvents used are partially toxic or for other reasons, in particular health and / or polluting nature, should not be used for asphalractor extraction. In addition, current normative and legislative changes prohibit the use of trichlorethylene, for example.

Experiments with alternative solvents from renewable raw materials, such as vegetable oil esters having a boiling point below 200 ° C such. B. Caprylsäuremethylester, have shown that these are not or only partially suitable for asphaltene extraction.

The object of the invention is therefore to provide an apparatus and a method available, which are used in the asphaltene extraction, whereby toxic, polluting or harmful influences are minimized.

Disclosure of the invention

An apparatus and method for extracting binders from road building materials is proposed.

This liquefied CO2 (carbon dioxide) is used to flush the road construction material as a solvent. By introducing or rinsing with the CO2 solvent, the binders are extracted from the road construction material.

Carbon dioxide is at atmospheric pressure below -78.5 ° C as a solid, the dry ice before. If this is heated, it does not melt, but sublimates, so goes directly into the gaseous state of aggregation. Solid carbon dioxide crystallizes in the cubic crystal system in the space group Pa3 with the lattice parameter a = 562.4 pm.

The critical temperature is 31.0 ° C, the critical pressure 73.8 bar. Below the critical temperature carbon dioxide can be compressed by increasing the pressure to a colorless liquid. At room temperature, a pressure of about 60 bar is required. The raw gas resulting from the chemical processes generally has a purity of more than 95%. After separation of gaseous impurities and moisture, the compression takes place. The compressed CO2 gas then has a purity of over 99%. After further purification steps, drying is followed by molecular sieves and liquefaction. The CO2 liquefaction usually takes place at compression pressures, for example between 14 and 20 bar and temperatures of -40 to -25 ° C instead.

The solubility of CO2 in water is comparatively high. At 20 ° C under atmospheric pressure, the saturation is in equilibrium with the pure Carbon dioxide phase at 1688 mg / l, while it is achieved at 44 mg / l in a pure oxygen phase and at 19 mg / l in a pure nitrogen phase. Under standard conditions, the density of carbon dioxide is 1.98 kg / m ³ .

Industrially, carbon dioxide is used in a variety of ways. It is inexpensive, non-flammable and is used physically as a compressed gas, in liquid form, solid as dry ice or in supercritical phase. The chemical industry uses carbon dioxide as a raw material for chemical syntheses.

In liquid form, carbon dioxide is traded in compressed gas cylinders. Here riser bottles are used for liquid taking, which must be perpendicular to the removal. The riser bottle is basically operated without a pressure reducing valve. As long as there is still liquid carbon dioxide in the pressure bottle, the internal pressure is only dependent on the temperature. A measurement of the filling level is therefore only possible for both types of bottles via weighing. The removal rate is limited by the fact that by absorbing heat from the environment only liquid carbon dioxide must evaporate in the bottle again to rebuild the pressure corresponding to the temperature.

For the application of the method, a washout is used. For this purpose, this washout device has a plurality of modules arranged one above the other. In particular, three superimposed modules are used, which are each designed as a receiving cylinder. In a topmost arranged upper receiving cylinder, a screen cylinder for rinsing the binder from the road construction material is arranged. An outlet funnel is used to introduce the binder into a centrifuge in the middle receiving cylinder.

The middle receiving cylinder is arranged between the upper receiving cylinder and a lower receiving cylinder. "Above" means here in the direction of the ceiling, "below" in the direction of the floor of a room. This middle receiving cylinder has the running in a pressure range centrifuge.

The lower receiving cylinder serves to receive a collecting vessel for the extracted binder.

The washing device is arranged between stable clamping columns, so that they can be closed pressure-tight. For this purpose, a stable top plate is arranged at the upper end of the washout, with which the washout is sealed flameproof.

To liquefy the CO2, a specially designed compressor is used. In a collecting facility, the CO2 can be liquefied again.

• a) der Straßenbaustoff wird mittels verflüssigtem CO2 gespült. Dadurch werden die Bindemittel extrahiert,
• b) die extrahierten Bindemittel werden durch eine in einem Druckbereich eingebaute Zentrifuge zum Trennen der feinen Füllstoffe von dem Bindemittel durchgeleitet,
• c) die Bindemittel werden in einem Einsatzgefäß oder einem Behälter innerhalb eines Auswasch- bzw. Druckbereichs gesammelt,
• d) das verwendete CO2 wird mittels eines Kompressors aus dem Auswaschbereich abgesaugt und verflüssigt,
• e) das CO2 kann in eine Sammeleinrichtung weitergeleitet werden und einer Wiederverwendung als Spülmittel unterzogen werden.

The method for extracting the binders used in road building materials comprises the following steps:

• a) the road construction material is flushed by means of liquefied CO2. This extracts the binders
• b) the extracted binders are passed through a binder incorporated in a pressure range for separating the fine fillers from the binder,
• c) the binders are collected in a feed vessel or a container within a washout area,
• d) the CO2 used is extracted by means of a compressor from the washout area and liquefied,
• e) the CO2 can be forwarded to a collection facility and reused as a rinsing agent.

The liquefied CO2 can be sprayed onto the binder-containing road building material sample or it can be filled with it. The leached out binder flow through the inventive structure of the washout due to gravity down through the entire washout.

Alternatively, the binder dissolved out by the liquid CO2 may be conveyed through the washout area by pressure changes throughout the washout area.

The device according to the invention has the advantage that it is made up of modules, namely the upper, middle and lower receiving cylinders. These and the pressure-tight lid form a divisible washout area for introducing the necessary components.

Furthermore, it is advantageous that a built-in discharge funnel is arranged in the upper receiving cylinder, which allows a direct derivation of the binder in the center of the centrifuge, which is arranged in the washout / pressure area in the middle receiving cylinder.

A further advantage is the outlet funnel arranged in the washing-out area in the middle receiving cylinder, which allows a direct discharge of the extracted binding agent into a collecting vessel or a container underneath.

The washout area may be provided by means of a closure device acting as a combination of Head plate, clamping columns and hydraulic cylinders is formed to be sealed pressure-tight.

The inventive method has the advantage that the CO2 used by a CO2 compressor, which is designed for suction and liquefaction of CO2, can be recovered again.

The inventive method has the further advantage that a control of the temperature and pressure conditions, which are necessary to maintain the liquid CO2 in the washout, via measurements and control with one or more temperature sensors and one or more pressure sensors.

Further advantages and advantageous embodiments of the invention are the following description of the figures, the drawings and the claims removed.

An exemplary embodiment of the solution according to the invention will be explained in more detail below with reference to the attached schematic drawings. It shows:

1 shows a device for extracting binders from road building materials and

2 shows a schematic flow of the method for extracting binders from road construction materials

In 1 is a device for extracting binders from road building materials 10 shown. For applying the method comes a washout 12 for use. This washout device 12 has to several superimposed modules. In particular, three superimposed modules are used, which are each designed as a receiving cylinder. In an uppermost upper cylinder 14 is a screen cylinder 16 arranged to rinse the binder from the road construction material. A first funnel 18 serves to introduce the binder into a centrifuge.

A middle intake cylinder 20 is between the upper intake cylinder 14 and a lower receiving cylinder 22 arranged. "Above" means here in the direction of the ceiling, "below" in the direction of the floor of a room.

This middle intake cylinder 20 has a centrifuge running in a pressure range 24 on. This centrifuge 24 is driven by the motor M. Furthermore, the middle receiving cylinder 20 a second discharge funnel 21 for introducing the binder into a collecting vessel 26 on.

The lower intake cylinder 22 has the collecting vessel 26 for binders. These binders are via the second discharge funnel 21 initiated there.

The washout device 12 is between stable clamping columns 28 arranged so that it can be closed pressure resistant. This is at the top of the washout 12 a stable headstock 30 arranged with the washing-out device 12 is sealed pressure-tight.

The upper washout cylinder 14 comes with a cap 32 sealed pressure-tight.

A hydraulic cylinder 34 serves the bottom pressure-tight closure of the washout unit 12 ,

For the liquefaction of CO2 comes a specially designed compressor 36 for use. In a collection facility 38 The CO2 can be collected and recycled for reuse as a flushing agent.

The washout cylinders 14 . 20 and 22 form a pressure-resistant trained washout, said washout within the stable clamping columns 28 as well as the top plate 30 and the hydraulic cylinder 34 is under pressure and thus can also be referred to as a pressure range.

Furthermore, in the washout 12 arranged at least one temperature sensor and at least one pressure sensor. These serve to measure the corresponding values and thereby control the temperature and pressure conditions necessary to maintain the liquid CO2 in the washout area.

2 shows a schematic flow of the method for extracting binders from road construction materials.

• a) der Straßenbaustoff wird mittels verflüssigtem CO2 gespült, dadurch werden die Bindemittel extrahiert,
• b) die extrahierten Bindemittel werden durch eine in einem Druckbereich eingebaute Zentrifuge 24 zum Trennen der feinen Füllstoffe von dem Bindemittel durchgeleitet,
• c) die Bindemittel werden in einem Einsatzgefäß 26 oder einem Behälter innerhalb eines Druckgefäßes, nämlich eines unteren Aufnahmezylinders 22, gesammelt,
• d) das verwendete CO2 wird mittels eines Kompressors 36 aus dem Auswaschbereich abgesaugt und einer Wiederverflüssigung unterzogen,
• e) das CO2 kann in eine Sammeleinrichtung 38 weitergeleitet werden und einer Wiedervewendung als Spülmittel unterzogen werden.

The method for extracting the binders used in road building materials comprises the following steps:

• a) the road construction material is flushed by means of liquefied CO2, thereby extracting the binders,
• b) the extracted binders are passed through a centrifuge incorporated in a pressure area 24 to separate the fine fillers from the binder,
• c) the binders are placed in a beaker 26 or a container within a pressure vessel, namely a lower receiving cylinder 22 , collected,
• d) the CO2 used is by means of a compressor 36 aspirated from the washout area and subjected to re-liquefaction,
• e) the CO2 can be put into a collection facility 38 be forwarded and subjected to a reuse as a rinse.

The liquefied CO2 can be sprayed onto the binder-containing road building material sample or it can be filled with it. The leached out binder flow through the inventive structure of the washout 10 due to gravity down through the entire washout area.

Alternatively, the binder dissolved out by the liquid CO2 may be conveyed through the washout area by pressure changes throughout the washout area.

All in the description, the following claims and the drawings illustrated features may be essential to the invention both individually and in any combination.

LIST OF REFERENCE NUMBERS

10

Device for extracting

12

Auswascheinrichtung

14

upper receiving cylinder

16

Screen cylinder for rinsing

18

first funnel

20

middle intake cylinder

21

second funnel

22

lower intake cylinder

24

centrifuge

26

collecting vessel

28

span columns

30

stable headstock

32

cap

34

hydraulic cylinders

36

compressor

38

collecting device

M

engine

Claims (14)

Contraption ( 10 ) for extracting binders from road building materials, comprising a washing device ( 12 ), characterized in that the washing device ( 12 ) at least three approximately vertically stacked modules ( 14 . 20 . 22 ), the modules ( 14 . 20 . 22 ) are formed as a pressure-tight lockable receiving cylinder. Contraption ( 10 ) according to claim 1, characterized in that for pressure-tight sealing of the washing device ( 12 ) a head plate ( 30 ) above the upper receiving cylinder ( 14 ) and a hydraulic cylinder ( 34 ) below the lower receiving cylinder ( 22 ), which together with tensioning columns ( 28 ) form a pressure area. Contraption ( 10 ) according to one of claims 1 or 2, characterized in that the upper receiving cylinder ( 14 ) a pressure-tight closure lid ( 32 ), a screen cylinder ( 16 ) for extracting the binder and a first discharge funnel ( 18 ) to the expiration of the extracted binder. Contraption ( 10 ) according to one of the preceding claims, characterized in that the middle receiving cylinder ( 20 ) a centrifuge ( 24 ), wherein the centrifuge ( 24 ) serves to separate the binders and fine fillers, and a second discharge funnel ( 21 ) for introducing the binders into a collecting vessel ( 26 ) having. Contraption ( 10 ) according to claim 4, characterized in that the collecting vessel ( 26 ) in a lower receiving cylinder ( 22 ) is arranged. Contraption ( 10 ) according to one of the preceding claims, characterized in that a compressor ( 36 ) with the lower receiving cylinder ( 22 ), wherein the compressor ( 36 ) is designed for the re-liquefaction of CO2. Contraption ( 10 ) according to claim 6, characterized in that the compressor ( 36 ) with a collecting device ( 38 ), which serves to accommodate the re-liquefied CO2 and the collecting device ( 38 ) a connection to washout device ( 12 ) having. Device according to one of the preceding claims, characterized in that the washing device ( 12 ) has at least one temperature sensor. Device according to one of the preceding claims, characterized in that the washing device ( 12 ) has at least one pressure sensor. Method for extracting the binders used in road building materials, comprising the following steps: a) the road construction material is rinsed by means of a rinsing agent in a washing device and thereby passes through at least three receiving cylinders arranged one above the other ( 14 . 20 . 22 ), wherein the binders by using a screen cylinder ( 16 ) in the upper receiving cylinder ( 14 ), b) the extracted binders are passed through a in a pressure range in the middle receiving cylinder ( 20 ) built-in centrifuge ( 24 ) for separating the fine fillers from the binder, c) the extracted binders are placed in a feed vessel ( 26 ) within a pressure vessel, namely the lower receiving cylinder ( 22 d) the rinsing agent used from CO2, which is now in gas phase, is determined by means of a compressor ( 36 ) sucked out of the washout area and liquefied again, e) the liquid CO2 is transferred to a collecting device ( 38 ) and provided for reuse as a rinse. A method according to claim 10, characterized in that the rinsing agent is sprayed onto a binder-containing road building material sample or the binder-containing road building material sample is filled with it. A method according to claim 10 or 11, characterized in that the flushed binder by the modular structure of the washing device ( 12 ), namely by the in the upper receiving cylinder ( 14 ) arranged first funnel ( 18 ) and in the middle receiving cylinder ( 20 ) arranged second funnel ( 21 ), due to gravity flow down through the entire washout area. Method according to one of claims 10 or 11, characterized in that the dissolved out by the rinsing agent binders are promoted by pressure changes through the entire washout. Rinsing agent for use in the device ( 10 ) according to one of claims 1 to 19 and the method according to one of claims 10 to 13, characterized in that it is designed as liquid CO2.

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