WO2012115528A2 - Améliorations du recyclage des pneus et associées à celui-ci - Google Patents

Améliorations du recyclage des pneus et associées à celui-ci Download PDF

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Publication number
WO2012115528A2
WO2012115528A2 PCT/NZ2012/000023 NZ2012000023W WO2012115528A2 WO 2012115528 A2 WO2012115528 A2 WO 2012115528A2 NZ 2012000023 W NZ2012000023 W NZ 2012000023W WO 2012115528 A2 WO2012115528 A2 WO 2012115528A2
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Prior art keywords
rubber
rubber materials
recycling
heating
slurry
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Ceased
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PCT/NZ2012/000023
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English (en)
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WO2012115528A3 (fr
WO2012115528A8 (fr
Inventor
Dennis Brian WESTBROOK
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TYRE RECLAMATION SERVICES INTERNATIONAL Ltd
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TYRE RECLAMATION SERVICES INTERNATIONAL Ltd
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Publication of WO2012115528A2 publication Critical patent/WO2012115528A2/fr
Publication of WO2012115528A8 publication Critical patent/WO2012115528A8/fr
Publication of WO2012115528A3 publication Critical patent/WO2012115528A3/fr
Anticipated expiration legal-status Critical
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • C08J11/06—Recovery or working-up of waste materials of polymers without chemical reactions
    • C08J11/08—Recovery or working-up of waste materials of polymers without chemical reactions using selective solvents for polymer components
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/04—Disintegrating plastics, e.g. by milling
    • B29B17/0404—Disintegrating plastics, e.g. by milling to powder
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/02—Recovery or working-up of waste materials of solvents, plasticisers or unreacted monomers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/02—Separating plastics from other materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/02—Separating plastics from other materials
    • B29B2017/0213—Specific separating techniques
    • B29B2017/0268—Separation of metals
    • B29B2017/0272—Magnetic separation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2021/00—Use of unspecified rubbers as moulding material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2030/00—Pneumatic or solid tyres or parts thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2319/00—Characterised by the use of rubbers not provided for in groups C08J2307/00 - C08J2317/00
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2321/00—Characterised by the use of unspecified rubbers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/52—Mechanical processing of waste for the recovery of materials, e.g. crushing, shredding, separation or disassembly
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

  • the present invention is directed to methods of recycling tyres comprising the extraction of organic hydrocarbons and volatiles, the process typically yielding a volatile product fraction and a carbon rich product.
  • tyres are highly modified polymers and copolymers which have been optimised for vehicle use - notably toughness, longevity in use, traction, and resistance to chemicals.
  • tyres are not easy to break down or convert into usable materials.
  • the presence of steel belts in the majority of tyres also adds a further problem and limits available recycling options.
  • the present invention seeks to consider both the rubber materials of items such as tyres, as well as tyres in which steel is present.
  • tyres are shredded, primarily to reduce the bulk of the original tyre for landfill applications, and to further facilitate any further mechanical processes involving the tyre.
  • Typical shredded tyre pieces still have the steel from belts embedded in the rubber (which can limit use of the shredded material).
  • the typical size of shredded tyres can vary, though are typically of an average particle size of 100mm or less and nominally around 50mm.
  • the present invention considers the use of readily available shredded tyre material, and rubber crumb which is sometimes produced therefrom.
  • Dobozy' s work shows some promise as it can recover volatile fractions from the tyre, and which can be used as a saleable commodity.
  • the current applicant considers limits it from being a viable commercial process Firstly is the length of time required for pre-softening the rubber material. For an industrial scale process this would involve a huge number of large storage vats and large quantities of solvent (expense, and safety issues).
  • the process is not easily amenable to a continuous process, and would be rather slow as a batch process. If one considers the economics of throughput against capital expense of plant and materials, there are potential limitations associated with the method of Dobozy's patents.
  • a method for recycling rubber materials comprising steps of:
  • step (iv) subjecting the residue fraction of step (iv) to a heating stage to create a substantially dry carbon rich product.
  • a method substantially as described above, which includes a preliminary step of producing rubber crumb from shredded rubber by a milling process which includes a non-shearing action.
  • the non-shearing milling process comprises a hammering or impacting action.
  • the non-shearing milling process comprises a hammer mill.
  • the non-shearing milling process is optimised to separate non-rubber materials embedded in, or attached to, the shredded rubber from the rubber materials therein.
  • a method substantially as described above, in which the separation process is a magnetic separation process.
  • a method substantially as described above, in which there is a drying step to remove water and moisture from the rubber crumb before it is subjected to a wet milling process.
  • the designated extractant comprises one or more members of any one or more subgroups in the group comprising: preferred hydrocarbon extracts, preferred organic extractants, and preferred plant based extractants.
  • the group of preferred hydrocarbon extractants comprises: halocarbons, halogenated hydrocarbons, cyclic hydrocarbons, aromatic hydrocarbons, substituted cyclic hydrocarbons, substituted aromatic hydrocarbons, cyclohexane, dichoromethane, trichloroethane, xylene, benzene, hexane, heptane, pentane, light naphthas and petroleum distillates, mineral turpentines, kerosenes; all having a boiling point of less than 190°C, and a melting point of less than 50°C at standard atmospheric pressure.
  • the group of preferred organic extractants comprises: ethers, ketones, aldehydes, diethyl ether, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), butyraldehyde, aromatic and non-aromatic heterocylic compounds with rings comprising carbon and oxygen, dioxane, furan, tetrahydrofuran (THF), aromatic and non-aromatic heterocylic compounds with rings comprising carbon and nitrogen, pyridine, aromatic and non-aromatic heterocylic compounds with rings comprising carbon and sulfur, thiophene, alcohols, methanol; all having a boiling point of less than 250°C, and a melting point of less than 50°C at standard atmospheric pressure.
  • the group of preferred organic extractants comprises: ethers, ketones, aldehydes, diethyl ether, acetone, methyl ethyl ketone (MEK), methyl isobutyl
  • the group of preferred plant based extractants comprises: light vegetable oils, wood turpentines, wood alcohols, terpenes, pine oils, tall oils, oils extracted from wood, oils extracted from seeds, terpenoids, pinene, limonene, all having a boiling point of less than 250°C, and a melting point of less than 50°C at standard atmospheric pressure.
  • heating of the rubber slurry to remove distillate fractions comprises a step which occurs at a temperature of 190°C or less
  • a method substantially as described above, in which prior to heating of the rubber slurry there is at least one mechanical separation step to separate liquid from solid components.
  • a said mechanical separation step comprises one or more of: decanting, centrifuging, filtration, and fluid absorption into a medium from which it can be recovered.
  • the mechanical separation step comprises a pressurised filtration method.
  • heating of the rubber slurry to remove distillate fractions comprises a step which occurs at a temperature of 140°C or less.
  • heating of the rubber slurry to remove distillate fractions comprises a step which occurs at a temperature of 120°C or less.
  • heating of the rubber slurry to remove distillate fractions comprises a step which occurs at a reduced pressure, which is less than atmospheric pressure.
  • heating of the rubber slurry to remove distillate fractions comprises a step which occurs at a reduced pressure of 50 Torr or less.
  • heating of the rubber slurry to remove distillate fractions comprises a step which occurs at a reduced pressure of 5 Torr or less.
  • distillate fractions are reintroduced as designated extractant into the shearing mill.
  • said reintroduced distillate fractions comprise mainly recovered designated extractant from the rubber slurry.
  • a method substantially as described above, in which, when heating of the residue fraction occurs, distilled volatiles are collected.
  • a method, substantially as described above in which distilled volatiles are reintroduced to the rubber slurry and or distillate fractions occurring prior to the heating of the residue fraction.
  • a method, substantially as described above in which the method is performed as a sequence of batch steps.
  • Apparatus for performing the method substantially as described above comprising a shearing mill capable of wet processing, delivery means for rubber slurry produced by the shearing mill to a heating chamber, heating means for elevating the temperature of rubber slurry within the chamber, and distillation apparatus for recovering volatiles
  • rubber material shall refer to (typically) elastomeric materials commonly referred to in the trade, or industry, as rubbers. It shall include materials derived from natural rubbers, modified natural rubbers, and synthetic rubbers. In particular it includes materials comprising, or at least partially derived from, monomers such as isoprene, chloroprene, butadiene, and isobutylene.
  • rubber crumb as used herein shall refer to rubber materials whose average particle size is 25mm or less or can pass through a 25mm mesh. More preferably, the average particle size is 10mm or less.
  • the rubber crumb may, but not necessarily, be derived from tyres.
  • shredded rubber shall refer to rubber products and materials which have been comminuted to smaller than their original size, and/or screened to a threshold size.
  • the threshold size is typically an average particle size of 200mm or less, or can pass through a 200mm mesh.
  • the preferred size for the present invention is 75mm or less.
  • the shredded rubber may include impurities of which the most typical is steel (steel belted tyres).
  • reduced fines shall refer to an average particle size of ⁇ or less, more preferably 40/im or less, and even more preferably 20 ⁇ or less.
  • rubber slurry as used herein in shall refer to a composition containing liquid with solid particles substantially dispersed therein, and which may be gel-like (high viscosity) or fluid (lower viscosity) in nature.
  • dry as used herein shall mean substantially free of liquid, wherein liquid includes both aqueous and non-aqueous liquids.
  • distillate fraction as used herein shall mean a fraction recovered from a distillation process, or from a heated material.
  • reaction fraction shall mean the fraction remaining after a distillate fraction has been removed.
  • a significant difference between the present invention and that of Dobozy is the elimination of pre-softening step prior to milling of the rubber material. In commercial terms this is significant as it potentially speeds the process considerably and eliminates the need for storing large quantities of raw material while it softens, as well as reducing the amount of fluid solvents used in the process.
  • the present invention also avoids the hazards associated with storing large amounts of solvent and raw materials in holding vats.
  • the invention comprises taking a rubber material (as herein defined) and shear milling it in the presence of a designated extractant as a wet milling process.
  • the shear milling should reduce the rubber material particles to the size of reduced fines (as herein defined) and yield a slurry (also as herein defined).
  • the viscosity of the slurry may be chosen to suit the design of the plant (apparatus) and pumping/conveying means.
  • the slurry is then subjected to at least one heating step to remove volatiles as one or more distillate fractions.
  • this heating step is characterised as being of relatively low temperature (particularly compared to pyrolysis methods) being typically of 190°C or less, more preferably 140°C or less and ideally 120°C or less, though this also depends on user choice regarding the nature of the distillate product, and partly also on the extractant used.
  • This distillation may occur under a reduced pressure. Subsequently the remaining residue fraction can be heated to a higher temperature to remove any final volatiles remaining (which one may not wish to include in the initial distillate fraction(s)) and to convert the residue essentially to a carbon rich product.
  • This final stage is typically in excess of 200°C and typically around 350-400°C which is still low by pyrolysis standards. Prior to the final stage it appears that the combination of milling and chemical action of designated extractants has yielded a residue which is relatively easily converted to a carbon rich product (as opposed to the raw rubber material). The final stage may also be under a reduced pressure.
  • the first step is the preparation of a suitable raw material.
  • initial comminution is typically performed. This may be by the common process of tyre shredding which produces shredded particles typically around 50- 100mm average size. As the particles need to be made smaller to produce a rubber crumb (preferred raw material for shear milling) smaller sized shred particles are preferred. At this stage any steel belts are typically still embedded in the rubber, though some shredding machines do remove the steel reinforcing.
  • the shreds are introduced to impact milling apparatus (as opposed to shearing apparatus) to further reduce the particle sizes to that typical of rubber crumb.
  • a hammer mill will be used at this stage, though other mills can be considered.
  • the hammering/impact of this stage helps separate the rubber (as a crumb) from any remaining steel (this also depends on whether the shredding process has already removed the steel).
  • the resulting steel can be removed by a suitable method, such as magnetic separation. Steps to remove impurities, or excess moisture/water may also be performed.
  • a rubber crumb suitable for use with the milling portion of the present invention Rubber crumb (or similar products) from other sources may also be used or added.
  • hydrocarbon rich non-rubber materials may be added though the user will need to optimise for each implemented embodiment the quantity and nature of any other materials which are included. For instance, a small percentage of certain plastics (typically also shredded or in small pieces) may be combined with the rubber crumb.
  • the preferred milling apparatus is that which is commonly referred to as a hydrafiner within the pulp and paper industry.
  • the currently preferred output size is that of reduced fines (as herein defined).
  • the resultant output is a slurry (current thought to comprise the designated extractant, extracted compounds from the rubber material, and non-dissolved rubber particles.
  • the hydrafmer can be set to process material quite quickly.
  • Wet milling apparatus with a shearing action such as used for mechanical pulping in the pulp and paper industry, are required to quickly process large volumes of materials and are typically suitable.
  • Other types of shearing mixers such as in-line shearing mixers, can be considered providing they are designed to accommodate the size of the rubber crumb being introduced and the extractant being used. The result is the rapid processing of rubber crumb to a slurry product ready for the removal of volatiles.
  • This wet shear milling step may be set to be run as a batch process or as a continuous process, according to the design of the milling apparatus and remainder of the plant. A wide range of wet milling equipment exists, particularly for use in the food and pulp (paper) industries.
  • Such apparatus are sometimes referred to as hydrafiners, or in-line shearing mixers, and mechanical (as well as thermomechanical (TMP)) mills.
  • TMP thermomechanical
  • Each are typically characterised by providing a shearing force to the solid material in a wet environment. While the exact mechanism is not known, it appears that the application of shearing forces to the rubber solid material, in the presence of an extractant, facilitates the release of useful volatile and semi-volatile components from the rubber material and allows for an inline or continuous process to be achieved (c.f. Dobozy).
  • the rubber is reduced to a particle size typically around 30 to 50 ⁇ , and thus it is desirable that the milling equipment is able to perform this.
  • the slurry product can be moved to elsewhere in the apparatus, for an inline process, where it can be subjected to one or more distillation steps.
  • two consecutive distillation steps are performed.
  • the slurry may be heated to mild temperature usually not exceeding 130°C (though higher temperatures (typically not exceeding 190°C) may be used). This tends to remove most of the designated extractant components (depending on the extractant used) and volatile components able to be extracted from the rubber material. This may be recycled to the shearing mill, though may be "cleaned up" prior to reintroduction - e.g. further filtering, separation, distillation.
  • This slurry heating step may be performed under reduced pressure.
  • the pressure is typically reduced to full or partial vacuum. Typically 50 Torr or less is used, though can be varied and optimised by a user.
  • the temperature may be elevated more, reduced, or remain the same depending on the particular embodiment, raw materials, extractants, distillates being recovered, etc.
  • Various temperature and/or pressure profiles may be applied during any heating/distillation steps of the slurry.
  • This second step may represent a second distillation process within the same part of the process apparatus, though often represents a further step down the process line to allow for more continuous processing of the materials. Distillation techniques from within the petrochemical industry may be drawn upon.
  • distillation steps yield a residue fraction which can optionally be heated further (typically in excess of 200°C and commonly around 230-250°C).
  • the period and/or temperature profile will typically be until no further significant amount of volatiles are emitted (these volatiles can be recovered or diverted to an earlier distillation chamber (depending on the design of the plant and apparatus)).
  • the remaining product is typically a carbon rich product, though final heating stage(s) can affect the nature of this product (e.g. carbon content, whether it is an activated charcoal product, etc.). Reduced atmospheric pressure may also be applied during the final heating stage (which can also reduce possible combustion issues).
  • the recovery of carbon is dependent upon a number of factors such as the parameters used in a particular embodiment. By way of example, a carbon yield of around 7-15% is typical, with the remainder being recovered distillates (including extractants).
  • the carbon produced is typically equivalent to 'pyrolytic carbon' and may be used in carbon additive or carbon construction industries, including steel manufacture, carbon fibre, carbon coatings, inks, tyre manufacture. It also has application across a range of medical and biomedical applications and the range of applications in which it can be used is quite extensive.
  • the process of the invention involves a designated extractant.
  • This typically one or more liquids which may act on the rubber material in different ways. Some of these ways include: softening the rubber, plasticising the rubber, chemically extracting components in the rubber, lubricating the rubber particles in mechanical processes, chemically attacking and degrading the rubber, and dissolving the rubber.
  • softening the rubber plasticising the rubber
  • chemically extracting components in the rubber lubricating the rubber particles in mechanical processes
  • chemically attacking and degrading the rubber and dissolving the rubber.
  • Most of these components are characterised by having melting points under about 190°C at normal atmospheric pressure, and melting points below about 50°C (see below). While low melting point solids may be used (i.e.
  • extractants are generally organic in nature and typically comprise compounds and mixtures which can either or both: i) dissolve organic compounds which tend to be insoluble or have low solubilities in water, and ii) can degrade the physical characteristics of polymeric and rubber materials.
  • many organic solvents which are liquid at room temperature are capable of dissolving organic compounds, though some are better than others.
  • Preferred solvents in this area tend to include lower molecular weight ketones such as acetone and MEK (methyl ethyl ketone) for example; primarily straight chain hydrocarbons from about C 4 to C 8 ; halogenated hydrocarbons such as dichloromethane (DCM), trichloroethane, chlorofluorocarbons, etc.; some aldehydes such as butyraldehyde; various cyclic aromatic compounds such as benzene, xylene, toluene, etc; various cyclic non-aromatic compounds such as cyclohexane, etc.; various aromatic and non-aromatic heterocyclic compounds such as dioxane, furan, tetrahydrofuran (THF), pyridine, thiophene, etc; various esters; and various branched and substituted variants of the foregoing.
  • ketones such as acetone and MEK (methyl ethyl ketone) for example
  • some solvents tend to degrade polymeric materials such as rubber. Normally such degradation is relatively slow (hence Dobozy' s long period of pre-soaking) and even for Dobozy, the degree of degradation when measured over hours may only be sufficient to soften the rubbers.
  • introducing these extractants during a wet shearing process appears to often accelerate any degradation action, which may be due to at least either or both of the mechanical action of shearing, and the reduced fines size of the particles.
  • the resulting small size of the particles presents a much larger surface area on which extractants may act and thus the extractants can be more effectively than merely affecting the surface layers of bulk (large) sized particles (e.g. rubber shreds vs. reduced fines).
  • extractants which can degrade rubber polymers tends to vary according to the specific composition of the rubber, which for tyres can vary considerably. Hence not all compounds and mixtures may effectively degrade all rubbers, and some user optimisation may be required.
  • some examples of extractants which can be generally regarded as potentially degrading rubbers include: methanol, lower molecular weight ketones, lower molecular weight halocarbons such as dichloromethane, pine oils, pine and plant oil constituents such as pinene, limonene, and various liquid terpenoids, some tall oils (including tall oil esters), and wood and mineral turpentines. Again, this list is intended to be illustrative rather than exhaustive, and also varies according to the exact nature of the rubber material being used as a raw product.
  • the first group is categorised preferred hydrocarbon extractants and comprises: halocarbons, halogenated hydrocarbons, cyclic hydrocarbons, aromatic hydrocarbons, substituted cyclic hydrocarbons, substituted aromatic hydrocarbons, cyclohexane, dichoromethane, trichloroethane, xylene, benzene, hexane, heptane, pentane, light naphthas and petroleum distillates, mineral turpentines, kerosenes; all having a boiling point of less than 190°C, and a melting point of less than 50°C at standard atmospheric pressure.
  • the second group is categorised preferred organic extractants and comprises: ethers, ketones, aldehydes, diethyl ether, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), butyraldehyde, aromatic and non-aromatic heterocylic compounds with rings comprising carbon and oxygen, dioxane, furan, tetrahydrofuran (THF), aromatic and non-aromatic heterocylic compounds with rings comprising carbon and nitrogen, pyridine, aromatic and non-aromatic heterocylic compounds with rings comprising carbon and sulfur, thiophene, alcohols, methanol; all having a boiling point of less than 250°C, and a melting point of less than 50°C at standard atmospheric pressure.
  • the third group is categorised preferred plant based extractants and comprises: light vegetable oils, wood turpentines, wood alcohols, terpenes, pine oils, tall oils, oils extracted from wood, oils extracted from seeds, terpenoids, pinene, limonene, all having a boiling point of less than 250°C, and a melting point of less than 50°C at standard atmospheric pressure.
  • the choice extractant can be influenced by a number of factors - e.g. cost, characteristics of the rubber material, aggressiveness towards the rubber, aggressiveness towards processing apparatus, nature of the obtained distillate fractions, etc.
  • some embodiments of the present invention may be used to produced a fuel or a particular petroleum type fraction, rather than isolating components into relatively pure fractions.
  • the choice of extractant can have a bearing of the quality of the product. For instance, when producing a fuel, an extractant such as MEK (methyl ethyl ketone) may be very efficient, but too expensive (and too volatile) to remain in a distillate fraction intended for use as a fuel.
  • MEK methyl ethyl ketone
  • a diesel fuel for instance
  • a lower price extractant comprising turpentine or a light grade kerosene for example.
  • the resulting fuel product will be the combination of the extractant with extracted components from the rubber.
  • the user is provided with a great degree of choice to optimise the process, by suitable selection of raw materials, to tailor the product obtained from the process.
  • the first distillation recovery typically yields what is known in the industry as a kerosene product.
  • the second recovered distillate is what is known as a diesel product (light oil).
  • a jet fuel can be produced in the first distillate fraction.
  • Example 1 Preliminary optional steps for producing rubber crumb A bulk material comprising predominantly used tyres may be cleaned and washed to remove foreign materials and contaminants.
  • the bulk material is then shredded to provide rubber shreds which are nominally within the range of 40mm to 75mm (inclusive) particle size.
  • the shreds may be screened to remove larger particles which can be returned for re-shredding.
  • the shreds may be optionally dried to remove any excess moisture or water which may be present (though drying may take place earlier or later in the process of preparing a rubber crumb). Waste heat from subsequent distillation processes may be used for drying.
  • the shreds are then introduced to a hammer mill capable of reducing the size of the rubber material to a nominal size of 5mm to 10mm (inclusive) average particle size.
  • Steel from belted tyres may be present in the output.
  • the crumb output may be screened, and/or use various separation techniques (e.g. magnetic separation) to remove contaminants and metal which are present.
  • the result is ideally a rubber crumb of the above mentioned nominal size and which is relatively free on non-organic compounds and materials.
  • Example 2 Preparation of carbon rich product from rubber crumb
  • a rubber crumb is chosen as the raw material, ideally such as produced in example 1.
  • a small proportion (i.e. less than or equal to 25%) of other polymeric materials (e.g. plastics) may be included.
  • the dry crumb is introduced into a wet shearing mill such as a hydrafiner as used in the pulp and paper industry (though this may need to be modified to ensure any seals and fittings are not affected by the designated extractant, and reduce flammability or explosion issues - such modifications would be within the skill of a suitably qualified tradesperson dealing with flammable hazardous plant).
  • a wet shearing mill such as a hydrafiner as used in the pulp and paper industry
  • a designated extractant is introduced into the hydrafiner to maintain an approximate ratio (by volume to rubber crumb to designated extractant) within the inclusive range 20:80 to 65:35, and ideally around 50:50. Specific embodiments may be chosen to operate outside of this preferred range according to user preference.
  • Designated extractants for this example may comprise one or more of the following formulations: Formulation A: wood or mineral turpentine.
  • Formulation B a mixture of wood or mineral turpentine; pine oil, and optionally tall oil.
  • Formulation B low molecular weight aggressive solvents (e.g. dichloromethane, methylethyl ketone (MEK)) , with hydrocarbons (e.g. C4-C10 hydrocarbons, lower boiling point kerosenes, light naphthas (boiling nominally between 60°C and 190°C at atmospheric pressure).
  • solvents e.g. dichloromethane, methylethyl ketone (MEK)
  • hydrocarbons e.g. C4-C10 hydrocarbons, lower boiling point kerosenes, light naphthas (boiling nominally between 60°C and 190°C at atmospheric pressure).
  • the shearing mill is set up to produce a rubber particle of average nominal size of l/m to ⁇ , ⁇ (inclusive). In one preferred embodiment he preference is around 40 ⁇ . Nominally also the average time to reduce the rubber crumb to reduced fines of the above size should be set to be less than 10 minutes, with ideal processing rates (depending on the equipment) being less than 1 minute.
  • the output should be a slurry of reduced fines dispersed in extractant.
  • the slurry is of a gel like consistency.
  • a higher proportion of extractant can be used, but this also means more solvent to recover.
  • the next step(s) involve the recovery of volatiles.
  • Mechanical separation steps e.g. filtration (preferably under pressure), centrifuging, etc.
  • this could reduce the total amount of volatiles recovered from the slurry as the extractants may also have a tendency to potentially draw out further volatiles entrapped in the rubber fines in the slurry.
  • some optimisation for a given installation should be performed to test the economics of mechanical separation processes supplementing distillation and heating.
  • the slurry would be pumped to a suitable heating chamber which may comprise a heat pipe through which the slurry flows (there may be a temperature gradient along this pipe).
  • a suitable heating chamber which may comprise a heat pipe through which the slurry flows (there may be a temperature gradient along this pipe).
  • the slurry may be pumped (e.g. a screw conveyor or fluid pump) to a suitable chamber.
  • the slurry is initially heated to around 105°C to 120°C for the formulations given.
  • the volatiles which boil off are collected, and may be collected as different fractions depending on their intended end use.
  • Various fractional distillation techniques as used in the petrochemical industry may be employed according to user needs.
  • a cracking column (such as used in the petrochemical industry) is used).
  • the slurry is subjected to a second heating stage in which the pressure is reduced (ideally to 50 Torr or less (this will also be governed partly by the volume of volatiles still coming off) and finishing at a pressure of 5 Torr or less once the majority of volatiles have been distilled).
  • the temperature may optionally be increased to around 150°C to 180°C to drive off more stubborn volatiles.
  • the slurry temperature is raised to 260°C or higher, and preferably around 380-410°C. There may be a few more volatiles which are driven off at this stage, including break down products as the remaining residue fraction converts primarily to carbon.
  • the heating temperature and time continues until a suitably compositioned carbon rich product is obtained.
  • the heating parameters can be varied to obtain a product whose nature matches the user's requirements, though a charcoal product can be effectively obtained under the correct heating parameters, and which may comprise an activated charcoal product.
  • the product is typically an easy to crumble cake-like residue.
  • the aforementioned process is amenable to a batch or flow type process, particular due to the elimination of pre-soaking steps and the rapidity of action of the wet shearing stage. It is considered that a skilled reader can suitably design plant and apparatus (based on the description herein) which can implement the process as either a batch, part batch, or continuous flow process. Plant and technologies from the petrochemical industry can be applied in the design of any of these types of plant.
  • Example 3 Preparation of carbon rich product and distillates from rubber crumb
  • a rubber crumb is chosen as the raw material, ideally such as produced in example 1.
  • a small proportion (i.e. less than or equal to 25%) of other polymeric materials (e.g. plastics) may be included.
  • the dry crumb is introduced into a wet shearing mill such as a hydrafmer as used in the pulp and paper industry (though this may need to be modified to ensure any seals and fittings are not affected by the designated extractant, and reduce fiammability or explosion issues - such modifications would be within the skill of a suitably qualified tradespersbn dealing with flammable hazardous plant).
  • a wet shearing mill such as a hydrafmer as used in the pulp and paper industry
  • a designated extractant comprising wood or mineral turpentine is introduced into the hydrafmer to maintain an approximate ratio (by volume to rubber crumb to designated extractant) within the inclusive range 10:90 to 30:70, and ideally around 20:80. Specific embodiments may be chosen to operate outside of this preferred range according to user preference.
  • the shearing mill is set up to produce a rubber particle of average nominal size of ⁇ to ⁇ (inclusive). Nominally also the average time to reduce the rubber crumb to reduced fines of the above size should be set to be less than 10 minutes, with ideal processing rates (depending on the equipment) being less than 1 minute.
  • the output should be a slurry of reduced fines dispersed in extractant.
  • the slurry is of a fluid gel like consistency but again depends on a number of factors. A higher proportion of extractant can be used, but this also means more solvent to recover.
  • the next step(s) involve the recovery of volatiles.
  • Mechanical separation steps e.g. filtration (preferably under pressure), centrifuging, etc.
  • this could reduce the total amount of volatiles recovered from the slurry as the extractants may also have a tendency to potentially draw out further volatiles entrapped in the rubber fines in the slurry.
  • some optimisation for a given installation should be performed to test the economics of mechanical separation processes supplementing distillation and heating.
  • the slurry would be pumped to a suitable heating chamber which may comprise a heat pipe through which the slurry flows (there may be a temperature gradient along this pipe).
  • a suitable heating chamber which may comprise a heat pipe through which the slurry flows (there may be a temperature gradient along this pipe).
  • the slurry may be pumped (e.g. a screw conveyor or fluid pump) to a suitable chamber.
  • the slurry is initially heated to around 140 to 160°.
  • the volatiles which boil off are collected, and may be collected as different fractions depending on their intended end use.
  • the majority of recovered distillate at this temperature will be turpentine, which can be recycled either with, or without, further purification or refinement by distillation.
  • This step can be performed in a rotary kiln, though other heating equipment suitable for dealing with slurries may be used.
  • the resultant mass is then subjected to a second heating stage in which the pressure is optionally reduced (ideally to 50Torr or less (this will also be governed partly by the volume of volatiles still coming off) and finishing at a pressure of 5 Torr or less once the majority of volatiles have been distilled).
  • the temperature may optionally be increased to around 160°C to 240°C to drive off more stubborn volatiles, and higher if a reduced pressure is not used.
  • This stage is ideally conducted in a rotary kiln.
  • the temperature may be progressively increased, and/or any pressure reduction progressively increased, so that different distillate fractions can be recovered.
  • the slurry temperature is optionally raised to 260°C or higher (e.g. 300-400°C). There may be a few more volatiles which are driven off at this stage, including break down products as the remaining residue fraction converts primarily to carbon.
  • the heating temperature and time continues until a suitably compositioned carbon rich product is obtained.
  • the heating parameters can be varied to obtain a product whose nature matches the user's requirements, though a charcoal product can be effectively obtained under the correct heating parameters, and which may comprise an activated charcoal product.
  • the product is typically an easy to crumble cake-like residue.
  • the aforementioned process is amenable to a batch or flow type process, particular due to the elimination of pre-soaking steps and the rapidity of action of the wet shearing stage. It is considered that a skilled reader can suitably design plant and apparatus (based on the description herein) which can implement the process as either a batch, part batch, or continuous flow process. Plant and technologies from the petrochemical industry can be applied in the design of any of these types of plant.
  • Rubber crumb of average size 5mm was introduced into a hydrafiner (wet mill) with one or more of the following solvents: Methyl Ethyl Ketone (MEK) A, Toluene B, Turpentine C.
  • MEK Methyl Ethyl Ketone
  • Toluene B Toluene B
  • Turpentine C The ratio of solvent to rubber was maintained approximately within the range of 1 :3 (solid to liquid) to produce a slurry.
  • the average particle size of rubber particles in the slurry was approximately within the range of 20 to 100 micrometres.
  • the slurry had the consistency of a pulpable liquid.
  • the slurry was then subjected to the following steps: It was initially heated in a heat exchanger to a temperature approximately within a range of 135 to 180C.
  • the volatiles which typically comprise solvent, isoprene, kerosene, jet fuel, petrol and reflux are collected and these are used as fuel alternatives or for reprocessing through the system to effect different fuel alternative outcomes.
  • the jet fuel obtained typically has a low sulphur content (typically ⁇ 0.03% though the nature of the rubber can have a bearing on this) which puts it in the range for jet A fuel without further distillation or purification to reduce sulphur levels.
  • the parameters of the process can be set up to obtain kerosene, jet fuel, and diesel fuel products which do not require further refining or blending - which from a manufacturing and cost perspective, is quite significant.
  • the remaining slurry is then introduced to a rotary kiln where further heating and extraction of volatiles occurs leaving a dry carbon powder. ( equivalent to a Pyrolytic carbon)
  • Toluene produced good results in terms of crumb absorption and fuel output and quality but currently is not cost effective unless recovered. The use of cheaper less pure forms of toluene could be considered.
  • Kerosene produced poor results in terms of fuel output and quality and tended to produce a product with an incorrect flash point for use in a preferred fuel product, but this may not be a problem for products with other uses.
  • Plant derived Turpentine produced excellent results but currently has major drawbacks in terms of availability and cost otherwise would be very suitable for fuel type products.
  • the turpentines have had the least affect on plastic components or piping. Others dissolved some of these components over time.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)

Abstract

La présente invention traite les produits en caoutchouc, tels que ceux extraits des pneus, selon un procédé dans lequel un agent d'extraction est introduit dans le caoutchouc et soumis à un procédé de broyage humide afin de créer un matériau ressemblant à une bouillie. Les fractions volatiles de distillat sont récupérées de la bouillie et peuvent être utilisées comme combustible. Un chauffage supplémentaire peut produire un produit riche en carbone pratiquement sec, qui peut avoir les mêmes caractéristiques que le carbone pyrolytique.
PCT/NZ2012/000023 2011-02-25 2012-02-27 Améliorations du recyclage des pneus et associées à celui-ci Ceased WO2012115528A2 (fr)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9803085B2 (en) 2008-09-24 2017-10-31 Wright Asphalt Products Company System and method for high throughput preparation of rubber-modified asphalt cement
US10179479B2 (en) 2015-05-19 2019-01-15 Bridgestone Americas Tire Operations, Llc Plant oil-containing rubber compositions, tread thereof and race tires containing the tread
US10233120B2 (en) 2008-04-30 2019-03-19 Wright Advanced Asphalt Systems System and method for pre-treatment of rubber-modified asphalt cement, and emulsions thereof
WO2022080475A1 (fr) * 2020-10-15 2022-04-21 株式会社ブリヂストン Procédé de production de composition de caoutchouc, caoutchouc re-réticulé, pneu et produit industriel en caoutchouc
JP2022065596A (ja) * 2020-10-15 2022-04-27 株式会社ブリヂストン ゴム組成物の製造方法、再架橋ゴム、タイヤ及びゴム工業用品
FR3164214A1 (fr) * 2024-07-07 2026-01-09 Qinlong XIAO Méthode de production de caoutchouc régénéré à partir du recyclage de pneus usagés
US12612470B2 (en) 2020-10-15 2026-04-28 Bridgestone Corporation Rubber composition production method, re-crosslinked rubber, tire, and rubber industrial product

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CN110938450B (zh) * 2019-12-16 2020-10-09 华中科技大学 利用废轮胎加压热解制备热解油及柠檬烯的方法

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US3978199A (en) * 1975-01-30 1976-08-31 Hydrocarbon Research, Inc. Recovering carbon black from waste rubber
WO1991005818A1 (fr) * 1989-10-10 1991-05-02 John Geza Dobozy Methode et procede de recuperation de matiere elastomere
US5611492A (en) * 1995-05-01 1997-03-18 Hunt Industries Inc. Refuse tire grinder/separator
AU7891000A (en) * 2000-10-06 2002-04-15 John Dobozy Method and apparatus for recovering an elastomeric material

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10233120B2 (en) 2008-04-30 2019-03-19 Wright Advanced Asphalt Systems System and method for pre-treatment of rubber-modified asphalt cement, and emulsions thereof
US9803085B2 (en) 2008-09-24 2017-10-31 Wright Asphalt Products Company System and method for high throughput preparation of rubber-modified asphalt cement
US10093804B2 (en) 2008-09-24 2018-10-09 Wright Asphalt Products Company System and method for high throughput preparation of rubber-modified asphalt cement
US10179479B2 (en) 2015-05-19 2019-01-15 Bridgestone Americas Tire Operations, Llc Plant oil-containing rubber compositions, tread thereof and race tires containing the tread
WO2022080475A1 (fr) * 2020-10-15 2022-04-21 株式会社ブリヂストン Procédé de production de composition de caoutchouc, caoutchouc re-réticulé, pneu et produit industriel en caoutchouc
JP2022065596A (ja) * 2020-10-15 2022-04-27 株式会社ブリヂストン ゴム組成物の製造方法、再架橋ゴム、タイヤ及びゴム工業用品
US12612470B2 (en) 2020-10-15 2026-04-28 Bridgestone Corporation Rubber composition production method, re-crosslinked rubber, tire, and rubber industrial product
FR3164214A1 (fr) * 2024-07-07 2026-01-09 Qinlong XIAO Méthode de production de caoutchouc régénéré à partir du recyclage de pneus usagés

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