EP0692009A1

EP0692009A1 - Process for processing used or waste plastic material

Info

Publication number: EP0692009A1
Application number: EP94913053A
Authority: EP
Inventors: Rolf Holighaus; Klaus Niemann; Martin Rupp
Original assignee: Veba Oel AG
Current assignee: Der Gruene Punkt Duales System Deutschland AG
Priority date: 1993-04-03
Filing date: 1994-03-25
Publication date: 1996-01-17
Anticipated expiration: 2014-03-25
Also published as: EP0692009B1; CA2158032A1; HU218853B; WO1994022979A1; CN1049237C; JP2003129066A; DE4311034A1; PL310893A1; KR100390236B1; CZ254695A3; JP3385025B2; FI954685A; SK121695A3; ES2104375T3; FI954685A0; DE59402926D1; RU2127296C1; JPH08508520A; CZ292837B6; UA48954C2

Abstract

PCT No. PCT/EP94/00954 Sec. 371 Date Dec. 27, 1995 Sec. 102(e) Date Dec. 27, 1995 PCT Filed Mar. 25, 1994 PCT Pub. No. WO94/22979 PCT Pub. Date Oct. 13, 1994A process is disclosed for processing used or waste plastic materials in order to recover chemical raw materials and liquid fuel components by depolymerisation of the used materials, which are transformed into a pumpable and into a volatile phase. The volatile phase is separated into a gaseous phase and a condensate or condensable depolymerisation product, which are refined by standard usual procedures. The pumpable phase remaining once the volatile phase is separated is subjected to liquid phase hydrogenation, gasification, low temperature carbonisation or to a combination of said processes.

Description

Process for processing old or waste plastics

The invention relates to a method for processing old or waste plastics for the purpose of obtaining chemical raw materials and liquid fuel components.

The invention is based on a process for the hydrotreatment of carbon-containing material, in which polymers, in particular polymer wastes in comminuted or dissolved form, are added to a high-boiling oil and this mixture is hydrogenated in the presence of hydrogen in order to obtain fuel components and chemical raw materials (see DD 254 207 A1).

A process for converting used tires, rubber and / or other plastics into liquid, gaseous and solid products by depolymerizing treatment in a solvent under elevated pressure and elevated temperature has been described in DE-A-25 30 229. In particular, no harmful substances such as SO2, soot or the like should enter the atmosphere in this process. For example, after crushing and mixing with a recycle oil from the hydrogenation product, hydrogenation was carried out at a hydrogen pressure of 150 bar and a temperature of 450 ° C in the presence of substances catalyzing the cleavage and hydrogenation reactions is fed to a hydrogenation reactor.

DE-A-2 205 001 describes a process for the thermal treatment of waste and rubber, in which the waste is split at temperatures from 250 to 450 ° C. in the presence of an auxiliary phase which is liquid at the reaction temperature.

Reference is also made to an article by Ronald H. Wölk, Michael C. Chervenak and Carmine A. Battista in Rubber Age, June 1974, pages 27 to 38, relating to the hydrogenation of waste tires for the purpose of obtaining hydrocarbon-based liquid products boiling in the gas oil range and of carbon black that can be reused as a filler.

A method is also known in which polymer waste, in particular waste rubber, is dissolved in the residue products of petroleum processing. The resulting mixture is then coked to coke. there

ORIGINAL DOCUMENTS there are gaseous and liquid products. The latter are suitable as fuel components if appropriately refurbished, cf. DD 0 144 171.

The polymer concentration in the hydrogenation feed is, for example, between 0.01 and 20% by weight according to the process according to DD 254207. The common hydrogenating treatment of heavy oils with dissolved and / or suspended polymers is limited to hydrogenation processes in which the hydrogenation is carried out in tubular reactors with or without a suspended catalyst. If reactors were operated with fixedly arranged catalysts, the use of polymers was only possible to a limited extent, in particular if polymers were added which depolymerize already in the heating phase up to approximately 420 ° C. before the reactor enters.

This is where the task begins with processes for processing used plastics not just to add up to 20% by weight of used plastics to conventional refining processes for heavy oil conversion.

There is also the problem that chlorine-containing plastics also have to be processed in the chemical conversion of waste products containing plastics. The corrosive hydrogen halides which occur as gaseous fission products in the depolymerization according to the prior art methods require special precautions.

Another problem arises from the fact that some of the used or waste plastics used contain inorganic secondary constituents, such as pigments, metals and fillers, which can lead to difficulties in some depolymerization processes or in the processing of depolymerization products .

It is therefore also an object of the present invention to provide a method which tolerates these ingredients. They are concentrated in a phase from which they can then be fed to processing processes which also tolerate these ingredients, while other phases which are free of these inorganic secondary constituents have to be worked up less expensively. Another task is to relieve or better utilize complex and capital-intensive process steps such as smoldering, gasification or bottom phase hydrogenation with regard to the required throughput quantities.

The invention consists in a method for processing old or waste plastics for the purpose of obtaining chemical raw materials and liquid fuel components by depolymerizing the starting materials into a pumpable and a volatile phase, separating the volatile phase into a gas phase and a condensate or condensable depolymerization products which are subjected to standard refinery procedures, the pumpable phase remaining after separation of the volatile phase being subjected to a bottom phase hydrogenation, gasification, smoldering or a combination of these process steps.

In this process, the resulting gaseous depolymerization products (gas), the resulting condensable depolymerization products (condensate) and the pumpable, viscous depolymerization products containing, bottom phase (depolymerized product) are drawn off in separate substreams and condensate and depolymerized product are worked up separately from one another. The process parameters are preferably selected so that the highest possible proportion of the so-called condensate is produced.

Additional advantageous embodiments of the invention are described in the subclaims.

The plastics to be used in the present process are e.g. B. Mixed fractions from waste collections, including by Duale System Deutschland GmbH (DSD). In these mixed fractions z. B. polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymer blends such as ABS and polycondensates. Plastic production waste, commercial packaging waste made of plastic, residual, mixed and pure fractions from the plastic processing industry can also be used, the chemical composition of this plastic waste not being critical for the suitability for use in the present process. Suitable insert products are also elastomers, technical rubber articles or used tires in a suitable pre-shredded form. The used plastics or waste plastics come, for example, from molded parts, laminates, composite materials, foils or synthetic fibers. Examples of halogen-containing plastics are chlorinated polyethylene (PEC), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), chloroprene rubber, to name just a few important representatives. But also in particular sulfur-containing plastics, for example polysulfones or rubbers crosslinked with sulfur bridges, such as in old tires, are produced in large quantities and, in the presence of the appropriate equipment for pre-comminution and pre-sorting in plastic and metal components, are used for depolymerization and further processing Extraction of chemical raw materials or fuel components accessible. The sulfidic sulfur obtained in these pretreatment stages or chemical conversion processes with hydrogen accumulation in the process, like the hydrogen chloride, predominantly passes into the exhaust gas, which is separated off and sent for further use.

Among the old or waste plastics to be used in the present process, synthetic plastics, elastomers, but also modified natural substances can also be used. In addition to the polymers already mentioned, in particular thermoplastics, this also includes thermosets and polyadducts and products based on cellulose such as cellulose and paper. The products made from this include semi-finished products, individual parts, components, packaging, storage and transport containers and consumer goods. The semifinished products also include boards and boards (printed circuit boards) and laminated boards, some of which may still contain metal coatings and which, like the other products to be used, after comminution to particle or piece sizes of 0.5 to 50 mm, possibly of metal -, Glass or ceramic components can be separated using a suitable classification process.

The waste and waste plastics mentioned generally also contain inorganic secondary components such as pigments, glass fibers, fillers such as titanium or zinc oxide, flame retardants, pigment-containing printing inks, carbon black and also metals such as e.g. B. metallic aluminum. The old and waste plastics mentioned, the z. B. from the collections of the DSD in mixtures or batches of different compositions may contain up to 10, possibly up to 20% by weight of inorganic secondary components. These plastic mixtures are usually used in shredded or preconditioned form z. B. used as granules or chips or the like in the present process:

The process products of depolymerization are essentially divided into three main product streams:

1.) A depolymerizate in an amount between 15 and 85% by weight, based on the plastic mixture used, which, depending on the composition and the particular requirements, is to be fed into the bottom phase hydrogenation, the pressure gasification and / or possibly the smoldering (pyrolysis)

Product streams can be divided.

These are predominantly heavy hydrocarbons boiling at> 480 ° C., all of which contain inert materials, such as aluminum foils, pigments, fillers, which are introduced into the process with the waste and waste plastics.

Glass fibers included.

2.) A condensate in an amount of 10 to 80, preferably 20 to 50 wt .-%, based on the plastic mixture used, which boils in a range between 25 ° C and 520 ° C and up to about 1,000 ppm organically bound May contain chlorine.

The condensate can be z. B. by hydrotreating on firmly arranged commercial Co-Mo or Ni-Mo catalysts in a high-quality synthetic crude oil (Syncrude) or also directly in chlorine-tolerating chemical-technical or refining processes as a hydrocarbon-containing base substance.

3.) A gas in amounts of about 5 to 20 wt .-% based on the plastic mixture used, which in addition to methane, ethane, propane and

Butane can also contain gaseous hydrogen halides, such as mainly hydrogen chloride and volatile, chlorine-containing hydrocarbon compounds.

The hydrogen chloride can, for. B. wash out with water from the gas stream to obtain a 30% aqueous hydrochloric acid. The residual gas can be hydrogenated in a bottom phase hydrogenation or in a hydrotreater from organically bound chlorine and z. B. the refinery gas processing.

The individual product streams, in particular the condensate, can subsequently be further processed in the sense of raw material recycling, e.g. B. used as raw materials for olefin production in ethylene plants.

An advantage of the process according to the invention is that inorganic secondary constituents of the old or waste plastics are concentrated in the sump phase, while the condensate not containing these constituents can be processed further by less complex processes. In particular, by optimally setting the process parameters temperature and residence time, it can be achieved that, on the one hand, a relatively high proportion of condensate is formed and, on the other hand, the viscous depolymerizate of the bottom phase remains pumpable under the process conditions. A useful approximation is that an increase in temperature by 10 ° C. with an average residence time increases the yield of the products passing into the volatile phase by more than 50%. The residence time dependency for two typical temperatures is shown in FIG. 3.

The condensate yield can be additionally optimized by the further preferred procedural measures of adding catalysts, stripping with steam, low boilers or hydrocarbon gases, turbulent stirring or pumping over.

Typical of the present process is a condensate yield of about 50% by weight and more based on the total amount of the plastics used in the depolymerization. This advantageously considerably relieves the pressure-intensive process stages of pressure gasification, bottom phase hydrogenation and smoldering (pyrolysis).

The preferred temperature range for the depolymerization for the process according to the invention is 150 to 470 ° C. A range from 250 to 450 ° C. is particularly suitable. The residence time can be 0.1 to 20 hours. A range from 1 to 10 h has proven to be generally sufficient. The pressure is inventive method a less critical size. So it may be preferable to carry out the process under negative pressure, e.g. B. if volatile components have to be deducted for procedural reasons. Relatively high pressures are also practicable, however, they require more equipment. In general, the pressure should be in the range from 0.01 to 300 bar, in particular 0.1 to 100 bar. The method can preferably be good at normal pressure or slightly above z. B. run up to about 2 bar, which significantly reduces the outlay on equipment. In order to degas the depolymerizate as completely as possible and to further increase the proportion of condensate, the process is advantageously carried out with a slight negative pressure down to about 0.2 bar.

The depolymerization can preferably be carried out with the addition of a catalyst, for example a Lewis acid such as aluminum chloride, a radical-forming substance such as a peroxide or a metal compound, for example a zeolite impregnated with a heavy metal salt solution.

The depolymerization can take place under turbulent flow conditions, e.g. B. by mechanical stirrer, but also by pumping around the reactor contents.

Further preferred refinements of the method consist in depolymerization under inert gas, ie. H. Gas that is essentially inert to the feedstocks and depolymerization products, e.g. B. N2, CO2, CO or hydrocarbons. The process can also be carried out with the introduction of stripping gases and stripping vapors, such as nitrogen, water vapor or hydrocarbon gases.

In principle, it can be regarded as an advantage of the process that no hydrogen has to be added in this process step.

Suitable liquid auxiliary phases or solvents or solvent mixtures are, for example, used organic solvents, that is to say waste solvents, incorrect production batches of organic liquids, waste oils or fractions from petroleum refining, for example vacuum residues. The addition of solvents or foreign oils or recirculated own oils can also be dispensed with.

The depolymerization can be carried out in a conventional reactor, e.g. B. a stirred tank reactor with external circulation, which is designed for the corresponding process parameters, such as pressure and temperature, and whose container material is resistant to the acidic components that may arise, such as hydrogen chloride. In particular, if the depolymerization is carried out with the addition of a catalyst, suitable "unit operations" methods can be considered, such as those used for the so-called visbreaking of heavy crude oils or of residual oils from mineral oil processing. Possibly. they must be adapted accordingly to the requirements of the method according to the invention. This process stage is advantageously designed for continuous operation, i. H. the plastic is continuously introduced into the liquid phase of the depolymerization reactor and the depolymerizate and top product are continuously removed.

Compared to the subsequent work-up steps of smoldering, swamp phase hydrogenation or gasification, the outlay on equipment for depolymerizing is comparatively low. This applies in particular if the process is carried out in the vicinity of normal pressure, ie in the range from 0.2 to 2 bar. In comparison to hydrogenating pretreatments, the expenditure on equipment is also significantly lower. If the depolymerization process is carried out optimally, the subsequent process steps can be relieved by up to 50% and more. At the same time, a large proportion of condensable hydrocarbons is deliberately generated during depolymerization, which can be worked up to valuable products by known and comparatively inexpensive processes.

After the gas and condensate have been separated off, the depolymerizate is easy to handle, since it remains pumpable and in this form represents a good starting material for the subsequent process stages.

According to the invention, the depolymerizate and the condensate are worked up separately from one another. The condensable depolymerization products are preferably subjected to a hydrogenating refining on fixed granular catalyst. For example, the condensate can be subjected to conventional hydrotreating using commercially available nickel / molybdenum or cobalt / molybdenum contacts at hydrogen partial pressures of 10 to 250 bar and temperatures of 200 to 430 ° C. A guard bed for trapping entrained ash components or coke-forming components is expediently connected upstream, depending on the composition of the condensate obtained. The contact is arranged on solid trays as usual and the direction of flow of the condensate can be provided from the tray towards the top of the hydrotreating column or in the opposite direction. To eliminate acidic components such as hydrogen halide, hydrogen sulfide and. The like. The feeding of water, alkali compounds and possibly corrosion inhibitors into the condensation part of appropriate separators is expedient.

Instead of conventional hydrotreating, the condensable depolymerization products or the condensate can also be subjected to hydrogenating refining on a moving catalyst or in a flowing catalyst bed.

The condensate obtained during the depolymerization is, for example, an excellent feedstock for a steam cracker after it has passed through the hydrotreater.

The Z. B. Liquid product obtained in hydrotreater is processed as synthetic crude oil (syncrude) in conventional refinery structures for the production of fuel components or as a chemical raw material, for example for ethylene production in ethylene plants.

The gaseous constituents resulting from hydrotreating are suitable, for example, to be added to the products used for steam reforming.

In a further preferred embodiment, at least a partial stream of the depolymerizate is subjected to pressure gasification.

In principle, all entrained-flow gasifiers (Texaco, Shell, Prenflo), fixed-bed gasifiers (Lurgi, Espag) and Ziwi gasifiers are suitable as devices for pressure gasification. gas. Processes for the thermal cracking of hydrocarbons with oxygen are particularly suitable, as are carried out in processes of oil gasification by partial oxidation of the hydrocarbons as a flame reaction in a combustion chamber. The reactions are autothermal - not catalytic.

The crude gas consisting essentially of CO and H2 in the pressure gasification can be worked up to synthesis gas or used for the production of hydrogen.

In a further preferred embodiment, at least a partial stream of the depolymerizate is fed to a bottom phase hydrogenation. The bottom phase hydrogenation is particularly preferred when a high proportion of liquid hydrocarbons is to be obtained from the depolymerizate. For a detailed description of the use of a bottom phase hydrogenation for the production of benzing and, if appropriate, of diesel oil from crude oil, reference is made to German Patent No. 933 826.

The bottom phase hydrogenation of the pumpable liquid-viscous depolymerizate is carried out, for example, in such a way that any petroleum-derived vacuum residue is added and, after compression to 300 bar, hydrogenation gas is added. For preheating, the reaction material passes through heat exchangers connected in series, in which the heat exchange with product streams takes place, for example, a hot separator top product.

The reaction mixture, which has been preheated to typically 400 ° C., is further heated to the desired reaction temperature and then fed to the reactor or a reactor cascade in which the bottom phase hydrogenation takes place.

The components which are gaseous at reaction temperature are separated from liquid and solid components in a downstream hot separator under process pressure. The latter also contain the inorganic minor components.

The heavier oil components are separated from the gaseous fraction in a separator, which can be fed to an atmospheric distillation after expansion. In a downstream separator system, the process gases are first removed from the uncondensed portion, which are worked up in a gas scrubber and returned as recycle gas. The remaining amount of the hot separator product is freed from the process water, for example after further cooling, and fed to an atmospheric column for further work-up.

The bottom draw of the hot separator can conveniently be expanded in two stages and subjected to vacuum distillation to remove residual oil. The thickened residue, which also contains the inorganic secondary constituents, can be fed to the gasification device in liquid or solid form for the purpose of generating synthesis gas.

The residues obtained in the bottom phase hydrogenation (hot separator residue) and the smoldering coke obtained when the depolymerizate smells, each containing the inorganic secondary constituents, can be utilized by a further thermal process step, the residues arising there containing the inorganic secondary constituents e.g. B. can be further processed for the purpose of metal recovery.

The light and medium oil fractions obtained from the bottom phase hydrogenation can be used in refinery structures as valuable raw materials for the production of fuels or plastic precursors such as olefins or aromatics. If these products from the bottom phase hydrogenation should not be stable in storage, they can be subjected to the hydrotreating treatment provided for condensate or condensable components in the present process.

A preferred embodiment of the process according to the invention consists in that the pumpable viscous depolymerizate, after separating off the gaseous and condensable depolymerization products as a liquid product, is each divided into a partial gasification which is to be pressurized and also a partial stream to be fed to a bottom phase hydrogenation.

The division according to the invention of the pumpable viscous depolymerizate into a pressure gasification and into a partial stream to be fed to a bottom phase hydrogenation and possibly pyrolysis in connection with the separate processing of the condensable components in one hydrotreating step leads to one significantly improved plant utilization. Devices such as those developed for the pressure reduction of solid fuels or for the thermal cracking of hydrocarbons with oxygen or in plants for the sump phase hydrogenation of carbon-containing materials under high pressure are very capital-intensive plant parts, the throughput capacity of which is optimally utilized when they are relieved of feed materials, as previously separated in the present process as a condensate stream and subjected to a separate processing in a hydrotreater under comparatively mild process conditions.

Another preferred option of the present method is to subject at least a partial stream of the depolymerization to a smoldering process to obtain smoldering gas, smoldering tar and smoked coke.

The gaseous hydrogen chloride gas obtained during depolymerization or condensable in the form of an aqueous solution can be used separately in the sense of material recycling. Remaining fractions which are not components of the gaseous depolymerization products which can be converted into a liquid product yield and which u. a. chlorine-organic as well as sulfur- and nitrogen-containing compounds can be freed from the heteroatoms chlorine, sulfur, nitrogen or oxygen in the course of the bottom phase hydrogenation or the residue processing integrated into the same, which are separated off as hydrogen compounds.

Because of the partially significant halogen content of the waste plastics used, it is advantageous to subject the drawn-off gaseous depolymerization products to washing, in particular the hydrogen halides formed being able to be separated off as aqueous hydrohalic acids and recycled.

The gaseous depolymerization products, if appropriate freed from acidic components such as hydrogen halides, can preferably be fed to the hydrogen feed gas or the hydrogen cycle gas of the bottom phase hydrogenation. The same applies to the carbonization gases separated during smoldering. The combination of depolymerization, hydrogenating treatment of the preferred distillate constituents, bottom phase hydrogenation, gasification (partial oxidation) and / or smoldering of the depolymerizate of the bottom phase means that the latter treatment stages, which are technologically particularly complex and complex but tolerate inorganic ingredients, can be relieved in terms of capacity. The method according to the invention offers a high material recycling potential of the plastics used.

With a suitable combination of the process steps described, virtually complete material recycling of the organic carbon contained in the plastics used can be achieved. For the most part, the preservation and recycling of the carbon or hydrocarbon chains contained in the plastic waste used is realized. Even the remaining inorganic components can be recycled, e.g. B. a metal recovery. They can also be used at least partially in ground form as catalysts again in the bottom phase hydrogenation.

The process according to the invention with the main plant parts of a depolymerization device, a hydrotreater, pressure gasification, a bottom phase hydrogenation of a carbonization plant and the plant parts for working up the gaseous depolymerization products is illustrated in the diagram in FIG. In the figure, the system configuration with a smoldering system is shown in dashed lines as an optional system component. The distribution of the associated material flows is illustrated schematically by means of the line routing shown. The reference symbols in FIG. 1 have the following meaning:

1 depolymerization reactor

2 Hydrotreater 3 Swamp phase hydrogenation

4 gasification plant

5 smoldering plant

6 waste plastic

7 Vacuum residue 8 hydrochloric acid

9 gases (methane, ethane, propane, H2, etc.) 10 condensate

11 depolymerizate

12 gases (methane, ethane, propane, H2S, NH3, H2, etc.), (e.g. for steam reforming) 13 Syncrude II (e.g. for olefin plants)

14 synthesis gas (CO / H2)

15 slag, soot (e.g. for metal recovery)

16 gases (methane, ethane, propane, H2S, NH3, H2, etc.), (e.g. for steam reforming) 17 Syncrude I (e.g. for refinery)

18 hydrogenation residue (e.g. to the gasification plant)

19 gases (e.g. for phase hydration)

20 tar (e.g. for phase hydration)

21 coke (e.g. to the gasification plant)

A flow chart for the system configuration according to FIG. 1 is given as follows in the sense of an exemplary embodiment for the specified feed products.

The appropriately comminuted, possibly washed and dried waste plastic is continuously fed to the depolymerization reactor 1, which is provided with heating, stirring, pressure-maintaining devices, associated inlet and outlet valves and measuring and control devices for checking the level.

In a typical variant, based on the entire reaction product, 50.0% by weight of depolymerizate, 40.0% by weight of condensate, 5.0% by weight of gaseous hydrogen chloride and 5.0% by weight of other gases are taken off . The condensate is fed to hydrotreater 2, from which 35.0% by weight of a syncrude which is fed to an olefin plant and 5.0% by weight of gaseous reaction products which are fed to a steam reforming are withdrawn overhead.

25.0% by weight of the bottom phase hydrogenation 3 and 25.0% by weight of the gasification device 4 are fed in from the depolymerizate. 25.0% by weight of vacuum residue are fed to the bottom phase hydrogenation 3 as a recycle stream. There are 10.0% by weight of gaseous reaction products which are fed to steam reforming, 40.0% by weight of a syncrude which is fed to a conventional refinery structure and 5.0% by weight of residue which are gasified 4 Trains- can be deducted. The reaction product of the gasification device consists in a typical procedure of 24.0% by weight of a synthesis gas and about 1.0% by weight of an ash-containing soot.

Optionally, the product stream of the depolymerizate from reactor 1 can be partly fed to pyrolysis or smoldering plant 5 for the production of pyrolysis coke, smoldering tar and smoldering gas. The pyrolysis coke is fed to the gasification device, the smoldering tar and the smoldering gas of the bottom phase hydrogenation.

The inorganic secondary constituents enriched in the depolymerizate are further concentrated in the subsequent workup. If the depolymerizate is fed to gasification, the inorganic secondary constituents are subsequently found in the discharged slag. In the case of the bottom phase hydrogenation, they are contained in the hydrogenation residue and in the smoldering in the smoked coke. If the hydrogenation residue and / or the smoked coke are also fed to the gasification, all the inorganic secondary constituents entered in the process according to the invention leave the product to be processed as gasification slag.

FIG. 2 shows a preferred embodiment of the entry part for the old or waste plastics into the depolymerization plant with an associated work-up part for the gaseous and the condensable depolymerization products. The reference symbols in FIG. 2 have the following meaning:

I silo for waste plastic 2 depolymerization reactor

3 oven

4 circulation pump

5 suspension pump

6 Insert container 7 high pressure pump

8 capacitor

9 hydrochloric acid washers

10 gases

I I Fresh water 12 Aqueous hydrochloric acid

13 condensate, (e.g. for hydrotreater) 14 Vacuum residue

15 mixture of depolymerizate / vacuum residue (e.g. for the bottom phase hydrogenation)

16 conveyor

The old or waste plastic enters the silo 1 and from there into the reactor 2 via the conveying device 16. The reactor contents are heated by means of a circulation system consisting of a circulation pump 4 and a furnace 3. A stream is withdrawn from the circulation via the suspension pump 5, which flows into the insert container 6 Vacuum residue supplied via line 14 is mixed and then fed to further processing via high pressure pump 7. The gases and condensable components formed in reactor 2 are passed through condenser 8 and separated. After passing through hydrochloric acid washer 9, the cleaned gases 10 are passed on for further use. The acid components previously contained are removed after washing as aqueous hydrochloric acid 12. The condensate separated in condenser 8 is fed from there for further use.

example 1

Depolymerization of old plastics

In a stirred tank reactor with 80 m ³ content, which is provided with a circulation system with a capacity of 150 m ³ / h, 5 t / h mixed agglomerated plastic particles with an average grain diameter of 8 mm were pneu¬ matically registered. The mixed plastic was material that came from the household collection of the Dual System Germany and typically contained 8% PVC.

The plastic mixture was depolymerized in the reactor at temperatures between 360 ° C and 420 ° C. Four fractions were formed, the distribution of which is shown in the table below as a function of the reactor temperature:

I II III IV

T gas condensate depolymerizate HCI rci [% by weight] [% by weight] [% by weight] [% by weight]

360 4 13 81 2 380 8 27 62 3

400 11 39 46 4

420 13 47 36 4

The depolymerized material stream (III) was drawn off continuously and fed to a bottom phase hydrogenation plant together with petroleum-derived vacuum residue for further cleavage. The viscosity of the depolymerizate was 200 mPas at 175 ° C.

The hydrocarbon condensates (stream II) were condensed in a separate plant and fed to a suitable further processing in a hydrotreater. The gaseous hydrogen chloride (stream IV) was taken up with water and released as 30% aqueous hydrochloric acid. The hydrocarbon gases (stream I) were fed to the bottom phase hydrogenation plant for conditioning.

Example 2

Dechlorination of the condensate

Condensate from a depolymerization plant, which was obtained from a plastic mixture (DSD house collection) at a temperature between 400 and 420 ° C, was freed of HCI by washing with ammoniacal solution. It then had a Cl content of 400 ppm.

This pretreated condensate was subjected to a catalytic dechlorination process in a continuously operating apparatus. The condensate was first compressed to 50 bar and then subjected to hydrogen, so that a gas / condensate ratio of 1000 l / kg was maintained. The mixture was heated and reacted on a NiMo catalyst in a fixed bed reactor. After leaving the reactor, the reaction mixture was quenched with ammoniacal water so that the HCl formed completely passed into the aqueous phase. Before the reaction mixture was let down, a gas / liquid phase separation was carried out, so that the gas and liquid phases could be released separately. After relaxation, the liquid phase was broken down into an aqueous and an organic phase. The organic phase, which represented more than 90% by weight of the condensate used, showed the following Cl contents [ppm] depending on the chosen reaction conditions:

Under all reaction conditions, these condensate qualities correspond to the input specifications of a mineral oil refinery and can be fed there to top distillation or specific processing plants (eg a steam cracker).

Claims

1. Process for processing old or waste plastics for the purpose of obtaining chemical raw materials and liquid fuel components by depolymerizing the starting materials into a pumpable and a volatile phase, separating the volatile phase into a gas phase and a condensate or condensable depolymerization products, which are subjected to standard refinery procedures are, the pumpable phase remaining after separation of the volatile phase being subjected to a bottom phase hydrogenation, gasification, smoldering or a combination of these process steps.

2. The method according to claim 1, characterized in that the depolymerization at a pressure of 0.01 to 300 bar, preferably 0.1 to 100 bar, in particular 0.2 to 2 bar, a temperature of 150 to 470 ° C. , preferably 250 to 450 ° C. and a residence time of 0.1 to 10 h, preferably 0.5 to 5 h, and three partial streams in amounts of 1.) 15 to 85.0% by weight of a depolymerizate, from 2.) 10.0 to 80.0% by weight of a condensate and from 3.) 5.0 to 20.0% by weight of a gas mixture, based in each case on the plastic mixture used.

3. The method according to claim 1 and 2, characterized in that the depolymerization is carried out with the addition of a catalyst.

4. The method according to at least one of the preceding claims, characterized ge indicates that the depolymerization is carried out under turbulent flow conditions.

5. The method according to at least one of the preceding claims, characterized ge indicates that the depolymerization is carried out under inert gas.

6. The method according to at least one of the preceding claims, characterized in that the depolymerization using stripping media such as Nitrogen, water vapor, hydrocarbon gases or other low boilers is carried out.

7. The method according to at least one of the preceding claims, characterized in that the used plastics or waste plastics are liquid

Auxiliary phase is added.

8. The method according to at least one of the preceding claims, characterized in that the condensable depolymerization products are subjected to hydrogenating refining on a fixed bed catalyst.

9. The method according to at least one of the preceding claims, characterized in that the condensable depolymerization products or the condensate are subjected to a hydrogenating refining on a moving catalyst or in a flowing catalyst bed.

10. The method according to at least one of the preceding claims, characterized ge indicates that the gaseous depolymerization products, optionally with interposition of a wash for removing acidic components such as hydrogen chloride, are fed to the bottom phase hydrogenation.