DE4441699A1 - Process for recycling plastics in a steam cracker - Google Patents

Description

The invention relates to a method for recycling art substances in a steam cracker.

By means of the method according to the invention, plastics, for example, pure polymeric waste plastics, mixed art waste or foil waste, including any Dirt, sticking materials, fillers, leftovers etc., in high quality ingredients for the well-known Steam cracker process. These feeds will be again in the known steam cracking process in fission products such as Converted ethylene, propylene, C₄-mixtures, pyrolysis gasoline, etc., the same in almost equal or even higher yield incurred as if the steam cracker with the traditional Feedstocks such as naphtha, liquid petroleum gas (LPG) and gas oil is driven. It is by means of the method according to the invention therefore possible in the steam cracker process the above mentioned ones traditional feedstocks due to plastic waste wonnene starting materials to replace, with an admixture of Naphtha, LPG or gas oil to those obtained from plastic waste Starting materials is not necessary.

With the method according to the invention is therefore an essential Economic contribution to the recycling of plastics done.

Under the known steam cracking process is usually a Evaporation and heating of the starting materials at temperatures up to 650 ° C followed by treatment at generally 700 to 1100 ° C, for example 780-860 ° C, in the course of conventional Example, 0.02 to 10 seconds, for example 0.1 to 2 seconds in Understood the presence of steam.

As is known, the waste plastics generated in the garbage to about 70 wt .-% of polyolefins such as polyethylene and poly propylene, about 15% by weight of styrene polymers, to ca. 10 wt .-% of PVC and in small minor amounts of about 5 wt .-% of other plastics such as polyurethane, polyester and polyamide. These plastic waste are generally ver dirty, d. H. they still contain sticker materials, filling substances, residues of contents u. a. The plastic waste becomes more common wise sorted and therefore fall in various known ten fractions. Called the bottle or hollow  body fraction, consisting of bottles, containers, etc., in the essentially of polyolefins such as polyethylene or polypropylene exist, a mixed plastic fraction consisting essentially from polyolefins such as polyethylene (PE), polypropylene (PP), styrene polymer such as polystyrene (PS) and polyvinyl chloride (PVC); a Film fraction consisting essentially of PE and PP etc. and a light fraction consisting essentially of PE, PP and PS, in each case possibly with adhering dirt, adhesive materials, fillers, leftovers, etc. Essentially means that the factions other than the mentioned art only in minor quantities, for example less than 10 wt .-%, in many cases less than 5 wt .-%, and ins contain special less than 2 wt .-%.

To convert plastic waste into further processed products a number of methods are known and in the patent literature, such as catalytic or thermal processes, hydrocracking processes, extruder processes, etc. For example, in the Europ. Patent Application 0 502 618 Procedures described in the plastic waste, especially poly olefins, are converted into lower hydrocarbons. here at above plastic waste in a fluidized bed apparatus reacted at a temperature of about 300-630 ° C. The case falling lower hydrocarbons, such as paraffins or waxes, can by means of the known steam cracking process in olefins being transformed. By the combination fluidized bed apparatus / Known steam cracking process can waste plastics in the above Olefins are converted.

A disadvantage of this method can be seen that the recovered feedstocks for the steam cracker process naphtha must be added, so the conversion of plastic waste in cleavage products such as ethylene, propylene, etc. succeed not without Addition of traditional ingredients. Furthermore proves the solid handling in the fluidized bed always as after pieces. In addition, the magnification of such a process problematic in a large-scale order of magnitude.

In the patent application published on 16 September 1993 WO 93/18112 discloses a process for the preparation of olefins Plastic waste by setting a desired viscosity by thermal pretreatment of the plastic waste in one Temperature range from 380 to 680 ° C and subsequent thermal Treatment of the product at a temperature of 700 to 1100 ° C described. The process does not affect distillation  separation of the product. The process can not be residue-free produce vaporizable product.

PCT application EP 94/01647 describes a method in which a melt obtained from plastic waste at 400 to 550 ° C converted into products, from the products one Separates distillate fraction and feeds it to a steam cracker.

Inert conditions when melting the plastic waste not described.

The object was to provide a method that can be used industrially, with the plastic waste in high valuable starting materials for any already existing Steam crackers are converted to make these feeds without adding, for example, naphtha, LPG and gas oil in the Steam Cracker Process Fission Products such as ethylene, propylene, C₄-Ge Mix and pyrolysis gasoline are obtained in high yield can.

This object is achieved by reacting under inert conditions Plastic waste melts, the melt obtained at 370 to 550 ° C preferably 380 to 530 ° C converted into products, from the Products a distillate fraction at 150 to 280 ° C, often at 200 to 280 ° C preferably at 220 to 260 ° C and especially at 230 separated up to 250 ° C and this as a feedstock a steam cracker supplies.

The melting and usually also the subsequent steps of the process according to the invention are carried out under inert conditions, ie while avoiding oxygen. As a result, who the undesirable oxidation processes already during the melting cens and also during the subsequent pyrolysis prevented, the redu benefits of suitable for the steam crackers products. A particular advantage of the method is that the formation of Ultragiften such as halogenated dibenzodioxins and dibenzofurans (dioxin) is significantly reduced. For this purpose, the plastic waste before being fed into the melting device by exchanging the air with an inert gas such as nitrogen, argon, CO₂ or a hydrocarbon gas such as methane or a cracking gas, preferably nitrogen intertisiert. As a cracking gas well suited to the deduction 5 after removal of the HCl and deduction D in Fig. 2. Since no oxygen is introduced in the further process, the inert conditions are present during the entire process. In general, the oxygen concentration before the reflow device is below 10, preferably below 1% by volume.

An advantageous embodiment of the method is by standing process features characterized:

• Melting of plastic waste generally at 280 up to 380 ° C,
• - feeding the melt into a reactor, wherein at 370 to 550 ° C the polymers are converted into products that are in the Steam crackers in a conventional manner evaporated and split can be
• - Distillative separation of a distillate fraction at 150 to 280, preferably 220 to 260 and in particular 230 to 250 ° C from the products,
• - Return the remaining products in the reactor to the rear and solids and optionally inorganic acids and possibly aromatics and
• - Introducing the separated distillate fraction, optionally after further separation, as feedstock in the steam cracker.

In some cases, it has turned out to be advantageous the distillate fraction aromatics such as ethylbenzene and styrene before it is used in the Steamcracker. This can with known methods such as extraction or distillation. The aromatics can then be supplied for separate use are, for example, directly the aromatic fraction (pyrolysis gasoline) of the products of the steam cracker.

The process is advantageous for hollow body fractions and Film fractions used. The melting of the plastic ab Cases takes place preferably at 280 to 350 ° C, in some Cases at 300 to 350 ° C, especially 290 to 320 ° C and the Um conversion in the reactor preferably at 400 to 450 ° C.

Preference is given to separating the distillate fraction or fractions used the following process steps:

• - Separating the products by means of a directly connected downstream of the reactor 1st column, in
  • a bottom product obtained at 350 ° to 470 ° C., in particular 390 ° to 450 ° C., which is returned to the reactor after removal of the residues and solids, and in
  • a head product obtained at 150 to 280 ° C., preferably 220 to 260 ° C., in particular 230 to 250 ° C., which after partial condensation is fed to a second column at 70 to 150, in particular 100 to 120 ° C.,
• Separating the liquid / gas mixture obtained after the partial condensation by means of the above 2nd column, in
  • a liquid mixture leaving the bottom of the second column generally at 50 ° to 100 ° C., used on the one hand as reflux for the first column and on the other hand as feedstock for the steam cracker, and in US Pat
  • - At the top of the second column generally at 20 to 80 ° C exiting gas mixture, which is used as feedstock for the steam cracker.

Are found in the plastic waste appreciable shares, d. H. usually more than 5 wt .-%, of chlorine-containing plastic such as Polyvinyl chloride and / or aromatics-containing plastic such as styrene polymer, for example in a mixed plastic fraction, so it has proven to be advantageous, the Kunststoffab at 280 to 380, preferably 330 to 380, in particular 320 to 350 ° C, melting, at the same time the polyvinyl chloride dehydrohalogenated, and the conversion in the reactor at 390 to 530, preferably 400 to 480 ° C, in particular 410 to 460 ° C in Perform products.

Dehydrohalogenation is sufficient at the temperatures used generally a residence time of 1 hour to 20 hours. The the time required depends on the desired degree of dehydrohalogenation from and can be easily by the expert by simple preliminary determine. In some cases, especially if the dehydro halogenation after melting, for example at 250 to 300 ° C, the desired residence time can be up to about 5 days. This can advantageously during a Interim storage done.

The following are preferred for the separation of the distillate fraction Process steps used:

• - Separating the products by means of a directly connected downstream of the reactor 1st column, in
  • - One at 330 to 450, in particular 350 to 400 ° C accrue of the bottom product, which is recycled after discharging the residues and solids in the reactor, and in
  • - A obtained at 150 to 280, in particular 230 to 250 ° C of the overhead product, which is supplied after partial condensation of a second column at 70 to 150, in particular 100 to 120 ° C,
• Separating the liquid / gas mixture obtained after the partial condensation by means of the above 2nd column, in
  • - A at the bottom of the second column generally at 50 to 100 ° C exiting liquid mixture, which is used on the one hand as reflux for the 1st column, and on the other hand is supplied to a separation of aromatics suitable distillation or extraction unit, and in
  • - At the top of the second column generally at 20 to 80 ° C exiting gas mixture, which is used as feedstock for the steam cracker.

The supplied to the above distillation or extraction unit Liquid mixture is generally in

• - A liquid fraction, which is used as feed for the Steam Cracker is used, and in
• - An aromatic fraction separated.

The heat of condensation of the top product from the first column Can be used to generate water vapor of various pressures become.

The intertization usually takes place before the introduction the plastic waste into the melting apparatus. This can by a Intertgasdusche or by suitable inert gas Einlei tions in the conveyor and / or the upstream La ger or reservoir in a conventional manner done. If pneumatically conveyed, the inert gas offers itself as a conveyor medium on. Sometimes it is also an advantage, the inert gas, gege in addition, in the melting apparatus above or un initiate below the liquid level.  

Melting of plastic waste can be carried out in suitable apparatus done, which provide sufficient heat transfer and the ensure required mixing. Has proven the Stirred tank such as stirred tank or in particular intensive stirred tank, which can be equipped with heating jacket and / or internal heating. Usually, the reflow process is relatively fast, i. H. to 0.5 to 30 minutes, completed. Advantageously, for example when dehydrohalogenated, several of these stirring container, z. B. two or three, operated in cascade.

As a reactor for the conversion of the melt into products ge usual equipment such as stirred tanks or extruders can be used. Advantageous is a tube furnace. In many cases, it has proven to be favorable to supply a portion of the tube furnace ver las send reaction products to increase the residence time of the tube furnace again. In this procedure, the conversion reaction takes place to the products depending on the temperature and Verweilzeitverhältnissen partly in the return line used for this purpose, optionally in a dwell time instead. The tube furnace is generally a heat exchanger in which heat is transferred from the gas phase outside the tubes to the material in the tubes, for example the melt. It is advantageous to use a reformer furnace, coker oven, refinery furnace or, in particular, a tube cracking furnace, as used, for example, in the steam cracker (see, for example, Ullmanns Encyklopadie der technischen Chemie, 4th Edition, Volume 3 , page 476 and page 330 / 331).

Residues and solids in the context of this invention are those Substances which remain in the separation by distillation and, if anything, do not boil below 500 ° C. It concerns with For example, to the plastic waste adhering impurities paper residues, coking products, glass and metal residues, Sand, pigment residues, fillers or the like.

In the method according to the invention, it has proven to be advantageous Mead, the bottom product of the first column at least partially as heating medium through the heating jacket of the reflow tank too lead before it is returned to the reactor. The middle Residence time in the reactor is usually from 0.05 to 10 hours.

The inventive method is generally in a Pressure of 0.8 to 2.0 bar, preferably at atmospheric pressure, ie 1 bar, performed. The specified boiling points or boiling ranges refer to 1 bar.  

The plastic waste can be used undried or dry become. Depending on the dimensions of the melting plant and its Zu It may be necessary to remove the plastic waste by well-known methods such as shredding or grinding mince. With average particle sizes of 2 to 10 mm achieved good results. Particle sizes from 1 to 10 cm, in one Even uncrushed plastic waste is also present suitable.

Further features of the method according to the invention are the subject the dependent claims.

The process according to the invention is described in detail below by way of example with reference to a simplified process scheme; Fig. 1.

About a conveyor member 1 - for example, a screw conveyor, chain conveyor or pneumatic conveying - dry and shredded plastic waste 2 , for example, a hollow body fraction, from a storage container 3 a with a heating jacket or heating bundle equipped stirred tank 4 is supplied. The storage container 3 is made inert by introducing, for example, nitrogen from below ( 14 ). Residual oxygen leaves the system at 15 , where excess nitrogen is also released. It is useful to watch a known per se probe for controlling the oxygen concentration below the inert gas 14 before. In the stirred tank 4 , the plastic waste at about 300 ° C are converted into an easily pumpable melt. Dehydrohalogenation may take place if, due to a sorting error of the plastic waste, there is a slip of PVC. Any resulting HCl 5 is carried out by means of water by well-th method - not relevant to the invention - in aqueous HCL over, this can be fed to other production processes or neutralized with NaOH. The above melt is fed by means of a pump - forced circulation - a tube gap oven 6 (called further cracking furnace). In this cracking furnace, the polymers without the addition of hydrogen, steam, catalysts, solvents or diluents are converted into products that are vaporized and cracked in the steam cracker in a conventional manner who can. In this case, takes place at about 420 ° C, a thermal liquid cleavage, the further takes place in the cracking furnace possibly the Restde hydrohalogenation instead. The necessary heat is supplied externally, for example by oil or gas heating. The gap-furnace leaving liquid-vapor mixture is directly a Ko lonne 7 , for example, a reinforcing column fed. The bottom product is withdrawn at about 350 ° C, the higher-boiling, not converted into short-chain hydrocarbons products.

These are on the one hand returned directly into the cracking furnace and on the other hand, as a heat carrier through the melt in the stirring container and passed through the heating jacket of the stirred tank and ultimately returned to the cracking furnace. From the above bottoms product residues and solids 8 are discharged after exiting the column, for example by means of a hydrocyclone. 9 The at the head of the column at about 240 ° C exiting vapor mixture is after a partial condensation of a white direct column 10 , for example, a packed column, at about 110 ° C, respectively. The entering into the packed column liquid / gas mixture is washed with water or aqueous NaOH 11 in countercurrent; HCl possibly still contained in the gas is discharged as aqueous HCl or aqueous NaCl solution with the liquid keitsgemisch sump. The liquid mixture emerging at the sump = organic liquid / aqueous HCl or aqueous NaCl solution is separated vessel 12 in a downstream phase separation vessel. The specific lighter, organic phase is discharged on the one hand as feedstock A for the steam cracker from the process and on the other hand go as reflux of the column fed. The specific heavier, aqueous phase, possibly enriched with HCl or NaCl 13 , is discharged from the process. The exiting at the top of the packed column HCl-free gas mixture is also fed as feed B to the steam cracker.

Furthermore, with reference to the simplified method, it is the case, for example, for a mixed plastic fraction, FIG. 2:

About a conveyor member 1 - for example, a screw conveyor, chain conveyors or pneumatic conveying - zerklei nerte, dry plastic waste 2 , for example, a mixed plastic fraction, from a storage container 3 with a heating jacket or heating bundle equipped stirred 4 are supplied. The storage container 3 is made inert by introducing, for example, nitrogen from below ( 14 ). Residual oxygen leaves the system at 15 , where excess nitrogen is also released. It is useful to watch a known per se probe for controlling the oxygen concentration below the inert gas 14 before. In the stirred tank 4 , the plastic waste at about 350 ° C are converted into an easily pumpable melt. In this case, a dehydrohalogenation takes place up to 98-99%, based on the chlorine content in the PVC. The resulting HCl 5 is converted by means of water by known methods - not relevant to the invention - in aqueous HCl, this can be supplied to other production processes supplied or neutralized with NaOH. The above melt is fed by means of a pump - forced circulation - a cracking furnace 6 . In this cracking furnace, the polymers without the addition of hydrogen, steam, catalysts, solvents or diluents are converted into products that can be vaporized and cleaved in the steam cracker in a conventional manner. This takes place at about 450 ° C, a thermal liquid cleavage, further takes place in the cracking furnace, the Restdehydrohalogenierung instead. The necessary heat is externally, for example by oil or gas heating, led to. The cracking furnace leaving liquid-vapor mixture is directly a column 7 , for example, a reinforcing column supplied. The bottom product at about 380 ° C, the higher-boiling, not umgewan in short-chain hydrocarbons products withdrawn. On the one hand, these are recycled directly into the cracking furnace and, on the other hand, passed as heat transfer medium through the melt in the stirred tank and through the heating jacket of the stirred tank and finally returned to the cracking furnace. From the above bottom product residues and solids 8 are discharged after exiting the column, for example by means of a hydrocyclone. 9 The vapor mixture exiting at the top of the column at about 240 ° C. is fed to a further column 10 , for example a column body, at about 110 ° C. after a partial condensation. The column entering the packed column liquid / gas mixture is washed with water or aqueous NaOH 11 in countercurrent; the contained in the gas contained HCl is discharged as aqueous HCl or aqueous NaCl solution with the liquid mixture at the bottom. The at the bottom of passing liquid mixture = organic liquid / aqueous HCl or aqueous NaCl solution is separated in a downstream phase separation vessel 12 . The specific lighter, organic phase - see Table 11 - is supplied on the one hand to a suitable for the separation of aromatics distillation or extraction unit 20 and on the other hand fed as reflux of the column. The specific heavier, aqueous phase, enriched with HCl or NaCl 13 , is discharged from the process. The HCl-free gas mixture leaving the top of the packed column is fed to the steam cracker as feedstock D. The above distillation or extraction unit supplied organic liquid is separated on the one hand in the feedstock C for the steam cracker and on the other hand in an aromatic fraction X in a column 20 ge; both fractions are removed from the process.

The starting materials obtained can in Steamcracker in conven Licher manner be evaporated and split.

The inventive method has u. a. the advantage that at Operating the steam cracker with the one from the plastic waste obtained value product heating energy to naphtha as an insert can be saved. It comes without added water fabric, diluents or solvents and works prak  table depressurized. Furthermore, the method has the advantage that Steamcracker with residue-free volatile feedstocks too supply.

In some cases, it has been found to be favorable to recover from the discharged residues and solids 8 by customary gasification by known processes, such as Shell or Texaco processes (eg Ullmanns Encyklopadie der technischen Chemie, 4th Edition, Volume 14, p. 395 to 397), e.g. B. in a Zyklonver gaser to produce synthesis gas. The resulting slag can be dumped or used as a construction aid.

Frequently, the aromatics obtained from the distillation or extraction unit 20 , which is not itself relevant to the invention, can be further processed. It is generally a mixture of styrene, ethylbenzene, toluene and benzene as main constituents. They can be used, for example, in plants known per se for the conversion of ethylbenzene to styrene as described in Ullmanns Encyklopadie der technischen Chemie, 4th edition, volume 22, pages 293 to 309. Furthermore, they can after hydrogenation of the double bonds in so-called aromatic systems, in which from a mixture of benzene, toluene and xylene is prepared essentially benzene (Ullmann's Encyclopedia of Industrial Chemistry, 4th Edition, Volume 8, page 383 to 411) are used.

example 1

In the above-described system of FIG. 1, a hollow body fraction obtained from the company Duales System Deutschland GmbH, Bonn, Germany, whose plastic content essentially consists of polyethylene and polypropylene, including possibly adhering soiling, adhesive materials, fillers, contents residues, etc., is processed , It was rendered inert in the storage container at 14 with nitrogen. The oxygen content of the gas phase below the nitrogen inlet was 0.2% by volume. The starting materials A (liquid mixture) and B (gas mixture) for the steam cracker have the tabulated compositions, Tables 1 and 2.

The resulting from the steam cracker process fission products have the tabulated compositions; Tables 3 and 4. For comparison, in these two latter tables each stated the compositions of the cleavage products, if the steam cracker with the classic feed naphtha betrie ben will. The comparison shows that the yield of ethylene and propylene, if the steam cracker with the feeds  - Obtained from the hollow body fraction - is operated, higher is like running the steam cracker with naphtha. at the conversion of the hollow body fraction are the plastic Waste converted as follows:

organic liquid mixture = starting material A for steam crackers 75% by weight HCl-free gas mixture = feedstock B for steam crackers 15% by weight Residues (organic, high-boiling hydrocarbons and coke) 3% by weight Solids (incineration residues)  7% by weight 100% by weight

Example 2

In the above-described Appendix of Fig. 2 is obtained from the Fa. Dual System Germany GmbH, Bonn, mixed plastic fraction whose plastic content consists essentially of polyethylene, polypropylene, styrene polymer and polyvinyl chloride, including any adhering contamination, adhesive materials, fillers , Leftovers, etc. processed. It was rendered inert in the storage container at 14 with nitrogen. The oxygen content of the gas phase below the nitrogen inlet was 0.2% by volume. The resulting feedstocks C (liquid keitsgemisch) and D (gas mixture) for the steam cracker have tabular shown compositions, Tables 12 and 13th

The resulting from the steam cracker process fission products have the tabulated compositions; Tables 14 and 15.

The conversion of the Mixed Plastic Group became the art waste substances as converted below.

organic liquid mixture = feedstock C for steam crackers 33% by weight HCl-free gas mixture = starting material D for steam crackers 21% by weight Aromatic fraction, mainly benzene, toluene, ethylbenzene and styrene 28% by weight Residues (organic, high-boiling hydrocarbons and coke) 12% by weight Solids (incineration residues) 4% by weight HCl  2% by weight 100% by weight

The following abbreviations apply to the following tables:

HC = hydrocarbons, NA = non-aromatics, EB = ethylbenzene

Table 1

Blow molded fraction

Feedstock A = liquid mixture for the steam cracker, obtained from the process according to the invention

Table 2

Blow molded fraction

Feedstock B = gas mixture for the steam cracker, obtained from the process according to the invention

Table 3

Blow molded fraction

Cleavage product from the steam cracker

I) with the starting material A according to the method of the invention

II) with feed naphtha

Table 4

Blow molded fraction

Cleavage product - gas mixture - from the steam cracker

I) with the starting material B according to the method of the invention

II) with feed naphtha

Table 11

Mixed Plastic Group

Feedstock for the distillation or extraction unit for the separation of the aromatic fraction, obtained from the process according to the invention

Table 12

Mixed Plastic Group

Feedstock C for the steam cracker obtained from the process according to the invention and the distillation or extraction unit for the separation of the aromatics

Table 13

Mixed Plastic Group

Feedstock D = gas mixture for the steam cracker, obtained from the process according to the invention

Table 14

Mixed Plastic Group

Cleavage product from the steam cracker with the feedstock C according to the method of the invention

Table 15

Mixed Plastic Group

Cleavage product from the steam cracker with the starting material D according to the invention

Claims (10)

1. A process for recycling plastic waste in a steam crackers, characterized in that under plastic inert conditions melting plastic waste, the melt obtained at 370 to 550 ° C converted into products, from the products a distillate fraction at 150 to 280 ° C and separated as feedstock to a steam cracker feeds. 2. The method according to claim 1, characterized by the following process characteristics:

• - melting the plastic waste,
• Feeding the melt into a reactor, wherein at 370 to 550 ° C the polymers are converted into products,
• distillative separation of a distillate fraction at 150 to 280 ° C from the products,
• - Returning the remaining products in the reactor except for residues and solids and optionally inorganic acids and
• - Introducing the separated distillate fraction, where appropriate, after further separation, as a feedstock in the steam cracker.

3. The method according to claim 1 or 2, characterized in that one carries out the distillative separation of the distillate fraction from the products with the following process steps:

• - Separating the products by means of a directly downstream of the reactor 1st column, in
  • a bottom product obtained at 350 ° to 470 ° C., which is returned to the reactor after removal of the residues and solids, and in
  • a top product obtained at 150 to 280 ° C, which is supplied after partial condensation of a second column at 70 to 150 ° C,
• Separating the liquid / gas mixture obtained after the partial condensation by means of the above 2nd column, in
  • - A liquid emerging at the bottom of the second column keitsgemisch, which is used on the one hand as reflux for the 1st column, and on the other hand used as feedstock for the steam cracker, and in
  • - A gas emerging at the top of the 2nd column gas mixture, which is used as feedstock for the steam cracker.

4. A method for recycling of chlorine-containing and / or aromatics-containing plastic waste in a steam cracker according to claim 1 or 2, characterized by the following process characteristics:

• Melting the plastic waste at 280 to 380 ° C with dehydrohalogenation of the chlorine-containing plastic,
• Feeding the melt into a reactor, wherein at 390 to 530 ° C the polymers are converted into products,
• - Separating the above products by means of a directly downstream of the reactor 1st column, in
  • a bottom product obtained at 330 to 450 ° C, which is returned to the reactor after discharge of the residues and solids, and in
  • a top product obtained at 150 to 280 ° C, which is supplied after partial condensation of a second column at 70 to 150 ° C,
• Separating the liquid / gas mixture obtained after the partial condensation by means of the above 2nd column, in
  • - A liquid emerging at the bottom of the second column keitsgemisch, which is used on the one hand as reflux for the 1st column, and on the other hand, a suitable for the separation of aromatics distillation or extraction unit is supplied, and in
  • - A gas emerging at the top of the 2nd column gas mixture, which is used as feedstock for the steam cracker.

5. The method according to claim 4, characterized in that one of the distillation or extraction unit supplied in liquid mixture

• a liquid fraction used as feed for the steam cracker, and in
• - Separates an aromatic fraction.

6. Process according to claims 1 to 5, characterized gekennzeich net, that as plastic waste a hollow body fraction, best consisting of bottles and containers of essentially poly olefins with possibly adhering impurities, Adhesive materials, fillers and / or leftovers is set. 7. Process according to claims 1 to 5, characterized gekennzeich net that plastic waste as a mixed plastic fraction be consisting essentially of polyolefins, styrene polymer and polyvinyl chloride with optionally adhering contaminants cleaning materials, adhesives, fillers and / or contents rest is used. 8. Process according to claims 1 to 5, characterized gekennzeich net, that as plastic waste a film fraction, consisting essentially made of polyethylene, polypropylene, including any soiling, adhesive materials, filler fen, content remains, is used. 9. Process according to claims 1 to 5, characterized gekennzeich net, that as plastic waste a light fraction, consisting essentially of polyethylene, polypropylene, polystyrene including any soiling, adhesive materials, Fillers, leftovers, is used. 10. The method according to claims 1 to 9, characterized net, that the specified plastics still low in Waste containing wastes, such as polyurethanes, polyesters, poly amide, can be added.