DE4223246A1 - Sepn. of tar from mixts. of tar and solid material - comprising crushing, heating at specific pressure and water treating - Google Patents

Abstract

The method is for the sepn. of mixts. of tar and solid material such as road coatings contg. tar or tar-contaminated soils or slurries. The mixt. is reduced to a granular size of 8 mm or less and in the presence of low-molecular hydrocarbon cpds. and/or oxygen and/or water and/or carbon dioxide is heated in an over-critical condition under a pressure of 70 bars or more to a temp. of at least 100 deg.C. USE/ADVANTAGE - For the sepn. of mixts. of tar and solid material. To separate tar from solid materials for recycling purposes.

Description

The invention relates to a method for separation of mixtures of tar and solids such as tar road surfaces or tar-contaminated gusts the or sludge.

Tar is chemically long-chain, aromatic Hydrocarbon compounds, especially benzene understood rings or other ring structures. It these are to form surface molecules Sized ring connections, with several chains Surface molecules are cross-linked.

Tar, especially from brown coal, applies because of this chemical nature as highly karzi nogen and may in recent times in almost all mo industrialized countries without protective measures against Do not use soil or water contamination be det. Especially in road construction, the western industrialized nations, especially in the west Germany has been bitumen for a long time Petroleum derivative - used instead of tar; bitumen is considered largely harmless.

Nevertheless, in the wake of political change problems in Europe in recent times world-compatible disposal of tar-containing roads  coverings or tar-contaminated soils or sludges in focus. Because a large part of the Streets in the new federal states became one Made of topping containing brown coal tar. In the course of the other lignite spread there Processing also came off of road construction for partially large-scale contamination of soils with tar.

This is well known with regard to the road surfaces Process of "direct recycling" of road surface - ie the recycling of the road to be renewed outer blanket with the addition of fresh bitumen - not applicable; the risk of soil contamination tar becomes even after mixing with bitumen not significantly reduced, nor by other known methods of admixing cement or similar mineral supplements.

Disposal of tar is apart from one Combustion via a chemical conversion to um world-compatible products possible. The well-known Burning tar has an adverse effect the emergence of environmentally harmful combustion pro added up to the waste of energy.

Also the well-known pyrolysis, in which the is to be disposed of tare substances in an oven Exclusion of air at temperatures of 1500 ° C or we be heated and the resulting products by the inorganic fraction (sand, clay, etc.) ge separated and recycled has the disadvantage to dispose of that for heating up the whole  The amount of substance required a relatively large amount of energy is.

Proceeding from this, the invention has the sheep the task of a separation process, with which you can easily mix mixtures of tar and let solids separate.

According to the invention, this object is achieved by that the mixture to a grain size of 8 mm or less crushed and in the presence of low molecular weight larer hydrocarbon compounds and / or what hydrogen and / or water and / or carbon dioxide supercritical condition under a pressure of 70 bar or more to a temperature of at least 100 ° C is heated.

The main idea of the invention is that of surface moles cool condensed ring compounds of the tar with Cracking as little effort as possible, that is in compared to the original state of low molecular weight coals to separate compounds. The result is that from the tar contained in the mixtures liquid or gaseous products, which - given after condensation - the petrochemical Recovery can be supplied or as Lö detergent and all or part of the tar solve so that he in the dissolved state of the further ver evaluation is supplied. To achieve this goal The invention proposes the use of a printer kes of at least 70 bar, heating the Gemi to a temperature of 100 ° C or more as well additionally the presence of low molecular weight  Hydrocarbon compounds and / or hydrogen and / or water and / or carbon dioxide in supercritical condition.

The reaction mechanisms to be observed here proceed as follows: When applying a what hydrogen atmosphere reacts with the Tar, the long-chain, highly cross-linked aromatics mo Reading is broken up and into other coal water molecules with shorter chain lengths and higher hydrogen-carbon ratio delt that are further processed petrochemically can. Similarly, comparatively ge wrestle pressures and temperatures tar-containing sub punch through high under the environmental conditions reactive water or low molecular water compounds in other low molecular weight Ver bonds transferred to another chemical Recovery are easily accessible. By correspond appropriate setting of the operating conditions and by adding appropriately selected solutions teas also produce tar-dissolving substances which the tar released from the mixture and over which Solvent can be washed out and therefore accessible becomes.

The key advantages are that due to the end products received the further ver working the tar portion in the to be processed Mixtures significantly simplified or partially reuse or recycling of the mate rials becomes possible in the first place. Expressly the possibility of use must be pointed out  also chlorinated or fluorinated hydrocarbon compounds of matter.

In an expedient development of the invention it is proposed to react in the presence of alcohols and / or acetone at a pressure of 120 bar or less and a temperature of 300 ° C or less to perform. Alcohols and / or acetone in particular are low mo molecular hydrocarbon compounds used in the proposed relatively low temperatures and Printing, to split off the surface molecules, of which tar is made are suitable. The main advantage here is that at Application of the above-mentioned substances Comparative pressure and the required temperature wise can be kept low, thereby on the one hand, the energy requirement is reduced, on the other the technical controllability of the process rens is significantly improved.

A further modification of the invention sees the Use powdered nickel and / or nickelo xid as a catalyst. Advantageously is by the use of such a Kataly sators the chemical reaction taking place lighter or their productivity with regard to Splitting of the tar surface molecules increased.

Finally, the use of Friedel-Crafts-Ka proposed analyzers. As a result, According to the present invention, all those catalysts referred to in Friedel-Crafts reactions  are settable and which are the aromatic substitution in the presence of Al chloride or other transition designate metal chlorides.

Here, too, the advantage lies in the Accelerations achieved using a catalyst based on the splitting of tar molecules lying chemical reactions.

Further details, features and advantages of the Er can be found in the following description Take part of the exercise, in the drawing an embodiment of the invention explained in more detail is. It shows in a schematic representation a system for separating mixtures Tar and solids through disposal High pressure alkolysis.

The drawing shows the individual work stations who work according to the inventive method the facility.

As shown schematically by a transport machine with a front loading shovel ( 1 ), either paved road surfaces with a maximum tar content of 5% or contaminated soil or sludge in which the tar volume can rise to 50% are delivered. From a storage container ( 2 ), they are fed via a conveyor belt ( 3 ) designed as a conveyor belt to a bac kenbrecher ( 4 ), through which the shredding and then in a gyratory crusher ( 5 ) further crushing to a maximum grain diameter of 6 mm he follows.

The inorganic load is then reduced by water treatment in a container ( 6 ) and the substances thus obtained are then fed to a high-pressure reaction vessel ( 7 ). There is a heating to a maximum of 350 ° C and a pressure of maximum 120 bar in the presence of a low molecular weight hydrocarbon compound, such as. B. alcohol and / or hydrogen and / or water in a supercritical state. Conveyor belts ( 3 ) are located between the individual processing stations.

The supercritical liquid acts on the tar-containing compounds, if appropriate in the presence of a catalyst, and it, just like in the presence of low molecular weight hydrocarbon compounds, cracks the long-chain and crosslinked molecules into such lower molecular weights. The resulting gaseous compounds are discharged from the high-pressure reaction vessel ( 7 ), cooled and possibly fed to further petrochemical utilization. The inorganic cargo is, after it can be used for preheating the load for energetic reasons, applied, collected in a loading ratio ( 8 ) and z. B. reused in landscaping.

As a result, a process of through which an environmentally friendly disposal  mixture of tar and solids can.

Claims (5)

1. Process for the separation of mixtures of tar and solids such as tar-containing road surfaces or tar-contaminated soils or sludges, characterized in that the mixture is crushed to a grain size of 8 mm or less and in the presence of low molecular weight hydrocarbon compounds and / or hydrogen and / or water and / or carbon dioxide is heated in a supercritical state under a pressure of 70 bar or more to a temperature of at least 100 ° C. 2. The method according to claim 1, characterized by chlorinated and / or fluorinated hydrocarbon links. 3. The method according to claim 1 or 2, characterized through the use of alcohols and / or acetone at a maximum pressure of 120 bar and a ma maximum temperature of 300 ° C. 4. The method according to any one of claims 1 to 3, ge characterized by powdered nickel or nickel oxide as a catalyst.   5. The method according to any one of claims 1 to 4, ge characterized by the use of Friedel Crafts catalysts.