Method for treating a pourable, flowable or pasty starting substrate, and apparatus for carrying out the method

Abstract

The method according to the invention for treating a starting substrate, which contains at least one solid substance and at least one high-boiling hydrocarbon, comprises the following steps: adding a liquid extractant (B) to the starting substrate (A, A') in a mixing stage (3); homogenizing the starting substrate-extractant mixture in a homogenizing stage (5); splitting the starting substrate-extractant mixture (C) drawn off from the homogenizing stage (5) into a solids fraction (E), containing predominantly solids, and a liquid fraction (F), containing predominantly liquid, in a solids separation means (8); splitting the solids fraction (E), in batches, into a solids residue (G) and a vapor fraction (H) by vacuum evaporation means (9); isolating the extractant from the liquid fraction (F), so as to form a hydrocarbon-containing residue (K), in a thermal separation stage (11); recirculating the extractant isolated in the thermal separation stage (11), together with extractant recovered from the vapor fraction (H) emerging from the vacuum evaporation means (9), in order to add said extractant to the starting substrate (A, A') again; and separately discharging the hydrocarbon-containing residue (K) and the solids residue (G) from the treatment plant.

Description

[0001] Process for preparing a pourable, flowable or pasty starting substrate and device for carrying out the process

[0002] The present invention relates to a process for preparing a pourable, flowable, or pasty starting substrate containing at least one solid and at least one high-boiling hydrocarbon. Furthermore, the invention relates to a device for carrying out the process.

[0003] Solids within the meaning of the present invention are all substances whose softening point at ambient pressure is above 500 ° C. And high-boiling hydrocarbons within the meaning of the present invention are all hydrocarbons whose boiling point at ambient pressure is above 300 ° C. All other hydrocarbons are considered low-boiling within the meaning of the present invention.

[0004] Various industrial processes produce mixtures of substances which contain at least one solid and at least one high-boiling hydrocarbon within the meaning of the present invention. A typical example of this is metal chips and / or other metal particles which arise in metalworking and are contaminated with cutting oil, whereby corresponding mixtures of substances have a pasty or sludge-like consistency in the case of fine metal particles, as arise in particular when grinding metallic workpieces. Contaminated soils, in particular sands contaminated with crude oil, can also be considered a typical example of a mixture of substances containing at least one solid and at least one high-boiling hydrocarbon within the meaning of the present invention, since crude oil typically contains, among other things, high-boiling hydrocarbons within the meaning of the present invention.Yet another typical example of a mixture of substances containing at least one solid and at least one high-boiling hydrocarbon within the meaning of the present invention are products containing mineral fibers and bitumen (e.g. in the form of a mineral fiber fleece impregnated with bitumen); such mixtures of substances, which are pourable within the meaning of the invention at least after appropriate (mechanical) comminution, arise in large quantities, either as production waste or at the end of the intended service life of the product in question.

[0005] If there is no immediate use for the mixtures of substances in question, as is often the case, they are currently predominantly either landfilled or disposed of in a waste incineration plant. In several respects, both options are incompatible with the increasingly stringent requirements and objectives regarding sustainability, climate neutrality, energy efficiency, the circular economy, etc.

[0006] DE 42 33 584 A1 discloses a process for separating inorganic sludges containing low-volatility hydrocarbons. The process comprises the following steps: The preheated sludge, which has been diluted with water, is mixed with solvent in an extraction reactor in such a way that vortex flows are created in the oil phase which circulate the oil sludge to the interface with the solvent. The completely solids-free solvent extract is led in a first stage to a horizontal tube spray film evaporator with vapor recompression and in a second stage to a fluidized bed evaporator, which is preceded by a sedimenter. The extracted oil sludge is preheated and led to degassing to expel residual solvent. The degassed sludge is dewatered in a sludge evaporator with vapor recompression. The residual oils in the distillate are removed via a skimmer.The solids-free water is returned to the process, and the solid sludge is deposited in a landfill. This process is intended to process the oily sludge produced during the hot water process in bitumen production from tar sands, which was previously deposited in settling ponds, and to separate it into its main components.

[0007] US 2011 / 0094937 A1 discloses a process and a plant for processing, for example, bitumen or crude oil using a two-stage solvent extraction. The starting material is mixed with solvent in a mixer and then fed into a separator, which separates an asphaltene-free oil fraction from an asphaltene-containing mixture. The solvent from the asphaltene-containing mixture is recovered in a stripper, and the asphaltene-containing product is discharged and, if necessary, further treated. A vacuum separation system can be integrated into the plant, whereby the solid fraction is subjected to vacuum evaporation.

[0008] Against the background set out above, the present invention is directed to providing a treatment of the said substance mixtures which is improved in the above respects compared to the prior art.

[0009] The present object is achieved according to the present invention by a process for preparing a pourable, flowable or pasty starting substrate containing at least one solid and at least one high-boiling hydrocarbon, comprising the following steps:

[0010] - the pourable, flowable or pasty starting substrate containing at least one solid and at least one high-boiling hydrocarbon is mixed in a mixing stage with a liquid extraction agent in which the at least one high-boiling hydrocarbon contained in the starting substrate is soluble;

[0011] - the starting substrate-extractant mixture is subjected to active mixing in a homogenisation stage;

[0012] - the homogenised starting substrate-extractant mixture withdrawn from the homogenisation stage is subjected to a mechanical solids separation, dividing it into a solids fraction containing predominantly solids and a liquid fraction containing predominantly liquid;

[0013] - the solid fraction resulting from the mechanical separation of solids is subjected to vacuum evaporation in batches, dividing it into a solid residue and a vapor fraction;

[0014] - the extraction agent is isolated from the liquid fraction resulting from the mechanical separation of solids in a thermal separation stage, forming a hydrocarbon-containing residue in which the high-boiling hydrocarbons are enriched;

[0015] - the extractant isolated in the thermal separation stage is recycled together with extractant recovered from the vapor fraction resulting from vacuum evaporation for re-addition to the starting substrate;

[0016] - the hydrocarbon-containing residue resulting from the thermal separation stage and the solid residue resulting from the vacuum evaporation are discharged separately from the processing plant.

[0017] Through the synergistic interaction of the various, interrelated treatment steps, which take place in a defined sequence one after the other or in parallel to one another, it is possible in a surprisingly simple manner to break down the mixture of materials forming the starting substrate into fractions of comparatively high purity, so that material recycling is not only possible but - depending on the substances contained in the starting substrate - even economically profitable, not to mention the ecological advantages resulting from the avoidance of waste or the inerting of problematic substances.The high energetic efficiency of the process according to the invention benefits, among other things, from the synergistic effects which can be achieved by the combination - applied to the starting substrate to which a liquid extractant has been added - of the treatment of the solid fraction resulting from a mechanical solid separation by means of vacuum evaporation, the isolation of the extractant from the liquid fraction resulting from the mechanical solid separation in a thermal separation stage, and the recycling of the extractant isolated in the thermal separation stage together with extractant which results from the liquid fraction resulting from the vacuum evaporation.

[0018] The vapor fraction is recovered for re-addition to the starting substrate. In this functional interaction, the special qualities of vacuum evaporation, namely the evaporation of volatile components at temperatures substantially lower than ambient pressure, come into play.

[0019] The comparatively low temperatures in the various components of the processing plant designed to carry out the process according to the invention result in correspondingly low heat and therefore energy requirements. In addition, the heat required - particularly for vacuum evaporation (e.g. at an operating pressure of 0.05 bar at a temperature level of up to 350 °C) - can be provided and transferred in an energetically attractive way, e.g. by indirect heating of the starting substrate mixed with extractant in the vacuum evaporation stage by means of an electrically heated thermal oil. The advantages mentioned apply in particular to the separation of extractants under vacuum evaporation at very low temperatures, for example at only around 100 °C. Here, even renewable energy sources are well suited for heating the vacuum evaporation stage.

[0020] Since the material usability (including the achievable utilization proceeds) depends on the purity of the material streams discharged from the processing plant, namely the solid residue and the hydrocarbon-containing residue in which the high-boiling hydrocarbons are enriched, this flows into the economic efficiency of the processing method according to the invention just as much as the material value of the at least one solid contained in the starting substrate and the at least one high-boiling hydrocarbon contained in the starting substrate.And especially with regard to the purity of the material streams discharged from the processing plant, the processing method according to the invention offers outstanding advantages, particularly because the relevant parameters of the various treatment steps and stages can be excellently adapted to the respective starting substrate and its individual composition. This also includes the possibility of providing a multi-stage thermal separation stage or a cascade of several thermal separation processes (individually tailored to the individual high-boiling hydrocarbons) for starting substrates containing several different high-boiling hydrocarbons in order to promote the recovery of hydrocarbons that are as pure as possible.

[0021] Which extraction agent is used - circulated in the process according to the invention - depends on the type of high-boiling hydrocarbon. Organic solvents (e.g. toluene) are very suitable for various high-boiling hydrocarbons. But organic acids (e.g. citric acid) can also lead to very good results in individual cases, sometimes even better than organic solvents. If the starting substrate contains several different high-boiling hydrocarbons, specifically adapted extraction agent mixtures can also prove very suitable.

[0022] The present invention provides, as will be made clear in the following explanations, a complete and closed solution for the separation of high-boiling hydrocarbons from mineral or metallic solids. The key advantages are that no additional, undefined processing steps are required and that there is a clear distinction from processing methods based on pyrolysis technology. Thus, the present invention is also suitable for hazardous waste - unlike is the case for pyrolysis-based processing technologies. For safety reasons, pyrolysis technology can only be justified or used for non-hazardous, defined waste streams - at least in countries or regions with high safety standards, such as Europe.hazardous wastes with typically considerable physical and / or chemical variations in their composition can lead to the formation of unknown pyrolysis gases in pyrolysis reactors, which may have fatal consequences.

[0023] According to a first preferred embodiment of the invention, the starting substrate is subjected to comminution before the addition of the extraction agent. This allows the residence or treatment times in the various subsequent treatment stages to be kept comparatively short, which contributes to high efficiency.

[0024] Another preferred development of the process according to the invention is characterized in that the addition of the liquid extractant to the starting substrate and the active mixing of the starting substrate-extractant mixture take place in a single mixing reactor that combines the mixing and homogenization stages. This allows the structural complexity of the processing plant to be reduced compared to plants with structurally separate mixing and homogenization stages.

[0025] According to yet another preferred embodiment of the process according to the invention, the homogenized starting substrate-extractant mixture remains in a storage tank prior to mechanical solids separation. In this way, not only can particularly good results be achieved in the downstream removal of high-boiling hydrocarbons from the starting substrate-extractant mixture. Rather, allowing the homogenized starting substrate-extractant mixture to remain in a container prepared for this purpose (intermediate storage) also has a positive effect due to its buffering effect. This is particularly true given that in the process according to the invention, one of the downstream treatments, namely vacuum evaporation, takes place in batch mode.

[0026] As far as mechanical solids separation is concerned, various suitable methods and system components are available within the scope of the present invention. For various typical applications of the present invention, mechanical solids separation using a filter press or a screw press delivers very good results. Another very suitable system component for mechanical solids separation is a decanter. Particularly good results can be achieved with multi-stage mechanical solids separation, whereby, if necessary, two different mechanical solids separation technologies can also be combined.

[0027] Yet another preferred development of the invention is characterized in that the isolation of the extraction agent, in order to be able to recycle it, takes place in a multi-stage thermal separation stage. The advantages of such a multi-stage thermal separation stage become apparent in particular when the liquid fraction resulting from the mechanical solids separation contains not just two components, namely the extraction agent and the high-boiling hydrocarbon extracted therewith, but at least three components, for example also water. Due to the multi-stage design of the thermal separation stage, it can be adapted very specifically to the individually different composition of the liquid fraction resulting from the mechanical solids separation.This facilitates a high degree of selectivity in the thermal separation stage, meaning a high degree of purity in the material streams withdrawn from the processing plant, which in turn has a very positive effect on the economic efficiency of the process according to the invention and the inventive processing of the starting substrate in question for the material recycling of its components. In particular, this allows the extraction agent intended for reuse to be recovered with a very high degree of purity, which not only benefits the quality of the treatment of the starting substrate but also—due to the low "losses" of extraction agent—the economic efficiency of the process.

[0028] In a particularly preferred embodiment of this further development, the multi-stage thermal separation stage can be realized by a combination of a thin-film evaporator and a condenser column, wherein by means of the thin-film evaporation the extractant and other low-boiling substances (e.g. water) are first separated as vapor from the high-boiling hydrocarbon, before the vapor mixture of extractant and other low-boiling substances (e.g. water) is then separated in the condenser column into individual condensate streams (e.g. extractant condensate and water condensate).The thermal separation stage, in which the extractant is isolated from the liquid fraction resulting from the mechanical solids separation to form a hydrocarbon-containing residue in which the high-boiling hydrocarbons are enriched, operates according to yet another preferred embodiment of the invention under an inert or inertized atmosphere (in particular under a nitrogen atmosphere). This prevents oxidation of the high-boiling hydrocarbons enriched in the hydrocarbon-containing residue, which benefits their quality and thus their usability as a material. This, in turn, can significantly benefit economic efficiency.

[0029] However, if - due to the composition of the starting substrate - the liquid fraction resulting from the mechanical solids separation contains only two substances, namely the extraction agent and the high-boiling hydrocarbon extracted with it, a very good result can be achieved with a single-stage thermal separation stage (e.g. in the form of a thin-film evaporator), although here too the extraction agent must be liquefied in a condenser before being used again.

[0030] In an alternative embodiment of the present invention, which is modified from the development explained above, a hydrocarbon-containing residue formed in the multi-stage thermal separation stage by removal of the extraction agent - with a corresponding composition - can be thermally separated into an aqueous fraction containing predominantly water on the one hand and an oily fraction containing predominantly hydrocarbons on the other.

[0031] fraction on the other hand. This separation, which is downstream of the extraction agent separation in terms of process technology, can in turn be carried out by means of thin-film evaporation, if the liquid fraction resulting from the mechanical solids separation has a suitable composition, possibly even in the same unit as the extraction agent separation.

[0032] In a preferred embodiment of the invention, the thermal separation stage operates under an inert or inertized atmosphere, preferably under a nitrogen atmosphere. Furthermore, in a preferred embodiment of the invention, the extractant isolated and recondensed in the thermal separation stage is temporarily stored before being reused. If necessary, the container in which the temporary storage takes place can also be used for additional treatment of the recycled extractant (e.g., by settling any suspended matter present).

[0033] Yet another preferred development of the invention is characterized in that the vapor fraction resulting from the vacuum evaporation is subjected to a multi-stage condensation to separate an aqueous condensate (and / or optionally an oily condensate) from the extractant contained in the vapor fraction. This embodiment takes into account that the circulating extractant does not actually reach the vacuum evaporation because it is already separated from the solid fraction fed to the vacuum evaporation upstream of this - namely in the mechanical solids separation upstream of the vacuum evaporation - but that a certain, more or less subordinate proportion of the extractant does nevertheless reach the vacuum evaporation as part of the solids fraction.In implementing this further development of the invention, this portion of extractant is also recycled (internally) through circulation, so that the loss of extractant is minimized.

[0034] In yet another, particularly preferred embodiment of the process according to the invention, the starting substrate is the residue from an upstream pretreatment stage in which a raw substrate is subjected to a pretreatment carried out as vacuum evaporation in such a way that at least one low-boiling hydrocarbon and / or any water contained therein is separated from the raw substrate. This development has proven to be particularly advantageous in the processing of a starting material (raw substrate) which contains water and / or various hydrocarbons which differ not only insignificantly in terms of their boiling point. This is because the early separation of the water orthe low-boiling hydrocarbons in the pre-treatment stage do not pass through the downstream section of the processing plant explained above and therefore do not burden it; this downstream section can therefore be specifically designed and dimensioned for the separation of at least one high-boiling hydrocarbon from the starting substrate. By removing low-boiling hydrocarbons and / or water from the raw substrate upstream of the extractant circuit, contamination of the extractant with water and low-boiling hydrocarbons is counteracted. This is a very important aspect for the economic viability of the process; in this way the extractant is available to the greatest possible extent for the removal of high-boiling hydrocarbons from the starting substrate. The early separation of water orThe removal of low-boiling hydrocarbons from the raw substrate in the pretreatment stage also simplifies the recovery of low-boiling hydrocarbons with a comparatively high degree of purity, which promotes material recycling.

[0035] To avoid any misconceptions, it should be pointed out as a precaution that a treatment stage which "only" precedes the process according to the invention explained further above in time, but which is carried out at least partly in the identical facilities which are used (with a time delay) for the process according to the invention (in its basic form), can also be considered as an "upstream" pretreatment stage in the above sense. In particular, in this sense the pretreatment carried out as vacuum evaporation can, if appropriate, be carried out in the same vacuum evaporator in which - in the process according to the invention in its basic form - the solid fraction resulting from the mechanical solids separation is also subjected (with a time delay) to vacuum evaporation in batches, with division into a solid residue and a vapor fraction.This is particularly useful when the quantities to be prepared are comparatively small and the vacuum evaporator is only sporadically required for carrying out the process according to the invention in its basic form.

[0036] Treatment plants, which are specifically designed by implementing additional, spatially / functionally completely independent

[0037] Pretreatment stage of components forming such for the

[0038] Carrying out the above-described pretreatment of a raw substrate by means of vacuum evaporation, in such a way that the pretreatment takes place in a separate area of ​​the plant, particularly preferably have a bypass to the said pretreatment stage, so that the substrate to be prepared (as the starting substrate) can be fed directly to the mixing stage, if necessary after prior comminution, bypassing the pretreatment stage. In other words: a material switch is provided here, via which the raw substrate is optionally fed either to the pretreatment stage or - as the starting substrate for the treatment according to the invention - directly to the mixing stage. This results in a processing plant which, in terms of process control, can be easily and flexibly adapted to the respective substrate to be prepared.This is a significant advantage, particularly for mobile processing plants, which are used successively at different locations to process a wide variety of substrates.

[0039] The process according to the invention, particularly in its preferred embodiments explained above, is suitable for processing a wide variety of starting substrates for which satisfactory, practical recycling processes have not yet existed. These include, in particular, starting substrates which contain at least one metallic solid. A particularly economically relevant example of this are starting substrates which arise in the metalworking industry and contain a mixture of metal particles and cutting oil. Another very important preferred application of the invention relates to the processing of starting substrates which contain at least one mineral solid. A particularly economically relevant example of this are starting substrates which arise during the decontamination of contaminated soil and contain a mixture of sand and crude oil.Yet another, economically equally significant application of the present invention relates to the processing of starting substrates containing fibrous solids, particularly metal, glass, or mineral fibers. Particularly economically relevant examples of this are starting substrates—obtained in the building materials industry—in which the high-boiling hydrocarbon contains bitumen.

[0040] The above explanations of the process according to the invention readily provide a person skilled in the art with the structural features of a device suitable and prepared for carrying out the process. In particular, a corresponding processing plant accordingly comprises at least the following components, which are coupled and interconnected as intended for carrying out the process according to the invention: material inlet for the starting material, mixing stage for admixing the extractant to the starting material, homogenization stage, separation unit for mechanical solids separation for dividing the starting substrate-extractant mixture into a solids fraction and a liquid fraction, vacuum evaporator for batchwise division of the solids fraction into a solid residue and a vapor fraction,thermal separation stage for isolating the extractant from the liquid fraction to form a hydrocarbon-containing residue, recirculation device for recycling the extractant recovered in the thermal separation stage by isolation together with extractant recovered from the vapor fraction of the vacuum evaporation for re-addition to the starting substrate, separate outputs for the hydrocarbon-containing residue and the solid residue.,

[0041] Advantageous structural developments of this device will become apparent to a person skilled in the art directly from the above explanations of preferred developments of the method according to the invention.

[0042] The present invention is explained in more detail below with reference to a preferred embodiment illustrated in the drawing. The drawing shows the relevant components and units of a processing plant suitable for carrying out the process according to the invention and the material flows characteristic of the process according to the invention. For the sake of clarity, the material flows (paths) and the respective flowing materials are designated by corresponding reference numerals.

[0043] The plant illustrated in the drawing for the inventive processing of a pourable, flowable or pasty starting substrate which contains at least one solid and at least one high-boiling hydrocarbon, has a material inlet 1 into which raw substrate is introduced. Downstream of the material inlet 1 is a material switch 2, by means of which it is possible to switch between processing the raw substrate with pretreatment or processing the raw substrate without pretreatment. In the basic concept - explained below - the raw substrate - without pretreatment - passes as starting substrate (path A) from the material inlet 1 via the switch 2 directly into a mixing stage 3, where it is mixed with a liquid extraction agent (path B) in which the at least one high-boiling hydrocarbon contained in the starting substrate is soluble.

[0044] The starting substrate-extractant mixture is then subjected to active mixing in a homogenization stage 4. In the illustrated preferred embodiment, however, the homogenization stage 4 and the mixing stage 3 form a structural unit in which both process stages take place, i.e., a uniform mixing reactor 5 combining the mixing stage and the homogenization stage.

[0045] The homogenized starting substrate-extractant mixture (path C) drawn from the homogenization stage 4 is fed to a buffer tank 6 for intermediate storage. From there, it is then fed (path D) to a separation unit 8 used for mechanical solids separation, illustrated here as a decanter 7. There, the starting substrate-extractant mixture undergoes mechanical solids separation, splitting it into a solids fraction containing predominantly solids (path E) and a liquid fraction containing predominantly liquid (path F). The optional multi-stage design of the mechanical solids separation has been explained in detail above, as has the use of a different separation unit 8 (e.g., a filter press).

[0046] The solid fraction resulting from the mechanical solid separation (path E) is fed to a vacuum evaporator 9 (e.g. VacuDry ® of the applicant), in which it is subjected to vacuum evaporation in batches, dividing it into a solid residue (cleaned of organic impurities) (path G) and a - leaving the vacuum evaporator 9 via a filter 10 -

[0047] Vapor fraction (path H). The solids contained in the starting substrate are concentrated in the solid residue.

[0048] The liquid fraction resulting from the mechanical solids separation (path F) is fed to a thermal separation stage 11, which is illustrated here as an example in two stages, namely as a combination of a thin-film evaporator 12 and a downstream condenser column 13. Here, the extraction agent and any water content (as vapor) are withdrawn from the liquid fraction (path I), specifically to form a hydrocarbon-containing residue (path K) that is fed in from the processing plant, just like the solids residue (path G). In this residue, the high-boiling hydrocarbons contained in the starting substrate are concentrated.

[0049] The extractant-water-vapor mixture (path I) discharged from the first stage of the thermal separation stage 11, i.e. the thin-film evaporator 12, is finally fed, together with the vapor fraction (path H) from the vacuum evaporator 9, to the condenser column 13 forming the second stage of the thermal separation stage 11, in which condenser column the extractant is isolated and separated from the water, namely by multi-stage liquefaction of the extractant-water-vapor mixture for separating condensation into an extractant condensate (path L) on the one hand and a water condensate (path M) on the other. The extractant condensate is temporarily stored in a buffer tank 14 before it is added again to the starting substrate in the mixing stage 4 (path B). The water condensate (path M) is discharged from the treatment plant.If the raw substrate to be processed contains not only at least one high-boiling hydrocarbon but also, to a significant extent, at least one low-boiling hydrocarbon, then - if the material switch 2 is switched accordingly - the raw substrate is pretreated in a pretreatment stage 15 which serves to separate out the low-boiling hydrocarbons. For this purpose, the raw substrate passes into a vacuum evaporator 17 via a dosing and feeding unit 16. The vapor fraction (path N) leaving this via a filter 18 and containing vaporous low-boiling hydrocarbon is liquefied in a condenser 19 so that it can be discharged from the processing plant in liquid form. In the illustrated embodiment, this condenser 19 is designed as a condenser column 20 against the background that, if required, moist, i.e.Water-containing raw substrate can be treated. In this case, a hydrocarbon-water vapor mixture, which also contains water vapor, leaves the vacuum evaporator 17 via the filter 18. This hydrocarbon-water vapor mixture is separated in the condenser column 20 by multi-stage liquefaction into a hydrocarbon condensate (path 0) on the one hand and a water condensate (path P) on the other. The water condensate from the pretreatment stage 15 and the water condensate from the thermal separation stage 11 are discharged together (cf. water outlet 21). Likewise, unless the separation is maintained with a view to separate utilization, the low-boiling hydrocarbons (path 0) and the high-boiling hydrocarbons (path K) can be discharged from the processing plant together, as shown (cf. hydrocarbon outlet 22).

[0050] If the raw substrate is pretreated in the described pretreatment stage 15 in the manner explained here, the starting substrate (path A') for the processing described in detail above is formed from the residue of the vacuum evaporation in the vacuum evaporator 17.

[0051] The plant shown in the drawing is suitable, for example, for the treatment of soils contaminated with crude oil. For this application, using toluene as the extraction agent, the operating parameters applied are within the ranges specified below:

[0052] Operating data of the vacuum evaporator 17 of the pretreatment stage 15: Internal pressure in the evaporator approx. 50 mbar abs; heating temperature up to approx. 400°C or

[0053] Material temperature up to approximately 300°C; average residence time approximately 240 minutes. The fraction leaving the vacuum evaporator 17 of the pretreatment stage 15 via path N contains water as evaporated components and hydrocarbons with a chain length of up to approximately 30°C.

[0054] The mixing ratio of extractant to solids in mixing stage 3 is approximately 2:1 or higher. The average residence time in buffer tank 6 is approximately 60 minutes.

[0055] From the solids separation taking place in the separation unit 8 (designed, for example, as a decanter), on the one hand - via path F - a liquid mixture of extractant and high-boiling hydrocarbons with a chain length > C 30 and on the other hand - via path E - a highly viscous mixture usually consisting of more than 50 wt.% mineral solids and extractant emerge.

[0056] Operating data of vacuum evaporator 9: Internal pressure in the evaporator approx. 50 mbar abs; heating temperature up to approx. 150°C or material temperature up to approx. 50°C; average residence time approx. 60 minutes. The fraction leaving vacuum evaporator 9 via path H consists of the extraction agent toluene.

[0057] Thus, after complete treatment, the main fractions leaving the plant are a crude oil fraction free of solids and solvents (path 22), which is prepared for material recycling in a refinery, a mineral fraction purified from crude oil with a feasible hydrocarbon target value of less than 0.1 wt.% (path G) and a water fraction (path 21).

Claims

Claims Process for the preparation of a pourable, flowable or pasty starting substrate containing at least one solid and at least one high-boiling hydrocarbon, comprising the following steps: - the pourable, flowable or pasty starting substrate (A, A') containing at least one solid and at least one high-boiling hydrocarbon is mixed in a mixing stage (3) mixed with a liquid extractant (B) in which the at least one high-boiling hydrocarbon contained in the starting substrate (A, A') is soluble; - the starting substrate-extractant mixture is subjected to active mixing in a homogenisation stage (4); - homogenized starting substrate-extractant mixture (C) withdrawn from the homogenization stage (4) is subjected to a mechanical solids separation (8) with division into a solids fraction (E) containing predominantly solids and a liquid fraction (F) containing predominantly liquid; - the solid fraction (E) resulting from the mechanical solid separation is subjected in batches to vacuum evaporation (9) with division into a solid residue (G) and a vapor fraction (H); - the extractant is isolated from the liquid fraction (F) resulting from the mechanical solids separation (8) in a thermal separation stage (11) to form a hydrocarbon-containing residue (K); - the extractant isolated in the thermal separation stage (11) is mixed with the extractant obtained from the vacuum evaporation (9) vapor fraction (H) is recovered, recycled for further addition to starting substrate (A, A'); - the hydrocarbon-containing residue (K) resulting from the thermal separation stage (11) and the solid residue (G) resulting from the vacuum evaporation (9) are discharged separately from the processing plant. Process according to claim 1, characterized in that the thermal separation stage (11) operates under an inert or inertized atmosphere, preferably under a nitrogen atmosphere. Process according to claim 1 or claim 2, characterized in that in the vacuum evaporation stage, the starting substrate mixed with extractant is indirectly heated by means of an electrically heated thermal oil. Process according to claim 3, characterized in that during the separation of extractants under Vacuum evaporation at very low temperatures, for example at only about 100°C, renewable energy sources are used to heat the respective vacuum evaporation stage. Method according to one of claims 1 to 4, characterized in that the starting substrate (A, A') is subjected to comminution before the addition of the liquid extractant (B). Method according to one of claims 1 to 5, characterized in that the addition of the liquid extractant (B) to the starting substrate (A, A') and the active mixing of the starting substrate-extractant mixture take place in a uniform mixing reactor (5) combining the mixing stage (3) and the homogenization stage (4). Method according to one of claims 1 to 6, characterized in that the homogenized starting substrate-extractant mixture (C) remains in a storage container (6) before the mechanical solids separation (8).Method according to one of claims 1 to 7, characterized in that a multi-stage mechanical solids separation (8) takes place. Method according to one of claims 1 to 8, characterized in that the mechanical solids separation (8) takes place at least partially in a filter press. Process according to one of claims 1 to 9, characterized in that the mechanical solids separation (8) takes place at least partially in a decanter (7). Process according to one of claims 1 to 10, characterized in that a multi-stage separation takes place in the thermal separation stage (11) with at least three outlets, namely an outlet for extractant, an outlet for an aqueous fraction containing predominantly water, and an outlet for an oily fraction containing predominantly hydrocarbons. Process according to claim 11, characterized in that a vapor mixture formed in a first stage of the thermal separation stage (11) is condensed in a second stage of the thermal separation stage to form a water condensate (M) on the one hand and an extractant condensate (L) on the other.Process according to claim 11 or claim 12, characterized in that in the thermal separation stage (11), the separation takes place by means of a thin-film evaporation (12) and a column condensation (13) downstream of this. Process according to claim 11, characterized in that a hydrocarbon-containing residue formed in the thermal separation stage (11) is thermally converted into a predominantly water-containing mixture. aqueous fraction and an oily fraction containing predominantly hydrocarbons. Process according to one of claims 1 to 14, characterized in that the extractant (L) isolated in the thermal separation stage (11) is temporarily stored after its re-liquefaction and before its reuse. Process according to one of claims 1 to 15, characterized in that the vapor fraction (H) resulting from the vacuum evaporation (9) is subjected to a multi-stage condensation to separate an aqueous condensate and / or an oily condensate from the extractant contained in the vapor fraction. Process according to one of claims 1 to 16, characterized in that the starting substrate (A') is the residue from the pretreatment stage (15), in which at least one low-boiling hydrocarbon is separated from a raw substrate by means of vacuum evaporation (17).Method according to claim 17, characterized in that the raw substrate is fed to the pretreatment stage (15) via a switch (2), which optionally also allows the alternative feeding of the raw substrate as starting substrate (A) directly into the mixing stage (3). Process according to one of claims 1 to 18, characterized in that the starting substrate (A, A') contains at least one metallic solid. Process according to claim 19, characterized in that the starting substrate (A, A') contains a mixture of metal particles and cutting oil or other high-boiling hydrocarbons. Process according to one of claims 1 to 18, characterized in that the starting substrate (A, A') contains at least one mineral solid. Process according to claim 21, characterized in that the starting substrate (A, A') contains a mixture of sand and crude oil. Process according to one of claims 1 to 18, characterized in that the starting substrate (A, A') contains fibrous solid, in particular glass or mineral fibers. Process according to one of claims 1 to 23, characterized in that the high-boiling hydrocarbon contains bitumen.The method according to claim 24, characterized in that the starting substrate consists of hydrocarbon-containing road rubble. The method according to one of claims 1 to 25, characterized in that the extraction agent preferably contains an organic solvent. consists at least predominantly of an organic solvent. Process according to one of claims 1 to 25, characterized in that the extractant contains an organic acid, preferably consists at least predominantly of an organic acid. Plant for the processing of a pourable, flowable or pasty starting substrate containing at least one solid and at least one high-boiling hydrocarbon, comprising the following components coupled and interconnected to carry out the processing process according to claim 1: material inlet (1) for the starting material, mixing stage (3) for admixing the extractant to the starting material, homogenization stage (4), separation unit (8) for the mechanical solids separation for dividing the starting substrate-extractant mixture into a solids fraction (E) and a liquid fraction (F), vacuum evaporator (9) for batchwise Division of the solid fraction (E) into a solid residue (G) and a vapor fraction (H), thermal separation stage (11) for isolating the extractant from the liquid fraction (F) to form a hydrocarbon-containing residue (K), recirculation device for recirculating the extractant recovered in the thermal separation stage (11) by isolation together with extractant which is obtained from the vapor fraction (H) of the vacuum evaporation is recovered for renewed addition to the starting substrate, separate outputs for the hydrocarbon-containing residue (K) and the solid residue (G). Plant according to claim 28, characterized by a thermal separation stage (11) set up for multi-stage separation with at least three outputs, namely an output for extraction agent, an output for an aqueous fraction containing predominantly water and an output for an oily fraction containing predominantly hydrocarbons. Plant according to claim 28 or claim 29, characterized by a pretreatment stage (15) in which at least one low-boiling hydrocarbon is separated from a raw substrate by means of vacuum evaporation (17), wherein preferably a switch (2) is provided for feeding raw substrate optionally to the pretreatment stage (15) or alternatively as starting substrate (A) directly into the mixing stage (3).

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