(US5216149-A)      Polyamide waste in a mixt. of polymer waste carried in a gas stream is selectively converted into a high value monomers or other high value product by a fast pyrolysis comprising (A) selecting a supported catalyst and a temp. range to obtain high yields of polyamide monomers and other high value products before other plastic wastes are affected and separating these high value products and (B) pyrolysing the remaining plastic waste at a higher temp. and recovering further high value monomers and other products.    The polyamide is pref. nylon 6 and caprolactam is recovered. (A) is carried out at 250-550, esp. 300-450 deg.C and (B) at 350-700, esp. 400-550 deg.C. The catalyst is NaOH, KOH, Ca(OH)2, NH4OH or an alkali or alkaline earth metal. The support is silica, alumina or CaCO3. The carrier gas is an inert gas, steam, CO2 or process recycle gas.    ADVANTAGE -   A controlled method to recover high value materials from plastic wastes. A fast process allowing selective recovery of these materials.    (US5300704-A)      Method comprises: (a) selecting a first temp. program range of 250-550 deg. C, to cause pyrolysis of the given polystyrene and phenolics compsn. and its high value monomeric constituent prior to a temp. range that causes pyrolysis of other plastic component; (b) selecting an acid or base catalysis and an oxide or carbonate support and treating the feed stream with the catalyst to effect acid or base catalysed reaction pathways to maximise yield or enhance sepn. of the high value monomeric constituent or high value prod. of the polystyrene and phenolics compsn. in the first temp. program range; (c) differentially heating the feed stream at a heat rate within the first temp. program range to provide differential pyrolysis for selective recovery of optimum quantities of the high value monomeric constituent or high value prod. of the polystyrene and phenolics compsn. prior to pyrolysis of other plastic components; (d) sepg. the high value monomer constituent or derived high value prod. from the polystyrene and phenolics; (e) selecting a second higher temp. program range of 350-700 deg. C. to cause pyrolysis to different derived high value prod. of the plastic waste and differentially heating the feed stream at the second higher temp. program range to cause pyrolysis of the plastic into the different derived high value prod.; and (f) sepg. the different derived high value prod.    USE/ADVANTAGE -   Pyrolysis of waste streams of plastic. Complex waste streams are controllable.    (US5321174-A)      The use of fast pyrolysis in a carrier gas to convert a polycarbonate and acrylonitrile butadiene-styrene plastic waste feed stream, having a mixed polymeric compsn., in a manner such that pyrolysis of a given polycarbonate and acrylonitrile butadiene-styrene and its high value monomeric constituent or derived high value prods. occurs prior to pyrolysis of other plastic components comprises: (a) selecting a first temp. programme range of 300-500 deg.C, to cause pyrolysis of a given polycarbonate and acrylonitrile butadiene-styrene and its high value monomeric constituent prior to a temp. range that causes pyrolysis of other plastic components; (b) selecting an acid or base catalyst and an oxide or carbonate support and treating the feed stream with the catalyst to affect acid or base catalysed reaction pathways to maximise yield or enhance separation of the high value monomeric constituent or high value prod. of the polycarbonate and acrylonitrile butadiene-styrene in the first temp. programme range; (c) differentially heating the feed stream at a heat rate within the first temp. programme range to provide differential pyrolysis for selective recovery of optimum quantities of the high value monomeric constituent or high value prod. of the polycarbonate and acrylonitrile butadiene-styrene prior to pyrolysis of other plastic components; (d) sepg. the high value monomer constituent or derived high value prod. from the polycarbonate and acrylonitrile butadiene-styrene; (e) selecting a second higher temp. programme range of 350-700 deg.C to cause pyrolysis to a different high value monomer constituent of the plastic waste and differentially heating the feed stream at the second higher temp. programme range to cause pyrolysis of the plastic into a different high value monomeric constituent or derived prod.; and (f) sepg. the different high value monomeric constituent or derived high value prod..    Pref. the high value monomeric constituent is from bis-phenol A and/or phenol; the supports are metal oxides and carbonates; and the carrier gas is from inert gases, steam, CO2, and processed recycled gases.    USE/ADVANTAGE -   Converting plastic waste to high value monomeric constituents. Minimises disposal requirements.    (US5359061-A)      Using fast pyrolysis in a carrier gas to convert a plastic waste feed stream comprising nylon 6(I) and a polyolefin (II) or mixts. of (II) in a manner such that pyrolysis of (I) and (II) and its high value monomeric constituent or derived high value prods. occurs prior to pyrolysis of other plastic components comprises: (a) selecting a first temp. program range to pyrolyse (I) and (II); (b) selecting a catalyst and a support and treating the stream to effect acid or base catalysed reaction pathways to maximise yield or enhance sepn. of the high value monomeric constituent; (e) differentially heating the stream; (d) sepg. the monomer constituent or derived high value prod. of (I) and (II); (e) selecting a second higher temp. program for pyrolysis; and (f) sepg. the different high value monomeric HC constituents or derived high value prods.    The polyolefin is pref. PP and the feed stream is e.g. carpet waste or textile waste.    USE/ADVANTAGE -   Used to convert waste plastics into useful chemicals. Makes plastics recycling cost-effective because it makes possible higher value prods. by tailoring the operation of the process.    (US5359099-A)      Using fast pyrolysis in a carrier gas to convert a PVC and polyurethane contg. plastic waste feed stream having a mixed polymeric compsn. such that pyrolysis of PVC and polyurethane yields its high value monomeric constituent (HVMC) or other high value derived prod. (HVDP) occurs prior to pyrolysis of the other plastic components, comprises (a) selecting a first temp. program range 200-400 deg.C, pyrolysing PVC and PU to yield HVMC prior to a temp. range causing pyrolysis of other plastics components; (b) selecting an acid or base catalyst and an oxide or carbonate support and treating the feed stream to maximise yield or enhance sepn. of HVMC or (c) differentially heating the feed stream at a heat rate within the first temp. range providing differential pyrolysis for selective recovery of optimum quantities of HVMC; (d) sepg. HVMC; (e) selecting a second higher temp. range 300-700 deg.C to cause pyrolysis of the plastic into a prod. (f) sepg. THF.    USE -   Provides useful high value monomer or other chemically and plastic waste used comes from e.g. carpet or textile wastes.    (JP7500121-W)      Using fast pyrolysis in a carrier gas to convert a plastic waste feed stream having a mixed polymeric compsn. comprises (a) selecting a first temp. programme range to cause pyrolysis of the given polymer and its high value monomeric constituent prior to a temp. range that causes pyrolysis of other plastic components; (b) selecting a catalyst and a support and treating the feedstream with this catalyst to affect acid or base catalysed reaction pathways to maximise yield or enhance sepn. of the high value monomeric constituent or high value prod. prior to pyrolysis of other plastic components therein; (d) sepg. the high value monomer constituent or derived high value prod.; (e) selecting a second higher temp. programme range to cause pyrolysis to a different high value monomeric constituent of the plastic waste and differentially heating the feed stream at this higher temp. programme range to cause pyrolysis of the plastic into different high value monomeric constituent or derived prod.; and (f) sepg. the different high value monomeric constituent or derived high value prod..    ADVANTAGE -   This pyrolysis of a complex waste stream of plastics, such as scrap plastics or mixed plastic waste from plants in which plastics are converted into consumer prods., converts the stream into useful high value monomers or other chemicals, by identifying catalyst and temp. conditions that permit decomposition of a given polymer in the presence of others, without decomposition of the other polymers, in order to make it easier to purify the monomer from the easier to decompose plastic. This minimises disposal requirements for nonbiodegradable materials and conserves non-renewable resources.    (US5386070-A)      A plastic waste feed stream contg. a mixt. of polystyrene and polyphenylene oxide is grouped such that pyrolysis of the polystyrene and polyphenylene oxide and its monomeric constituent and derived prod. occurs prior to pyrolysis of the other plastic components by (a) selecting a first temp. program range of 250-550 deg.C to cause pyrolysis of the given polystyrene and polyphenylene oxide and its monomeric constituent prior to a temp. range that causes pyrolysis of other plastic components; (b) selecting a catalyst and a support and treating the feed stream with the catalyst to affect acid or base catalysed reaction pathways to maximise yield or enhance sepn. of the monomeric constituent of styrene from the polystyrene and polyphenylene oxide in the first temp. program range; (c) differentially heating the feed stream at a heat rate within the first temp. program range to provide differential pyrolysis for selective recovery of quantities of the monomeric constituent of styrene from the polystyrene and polyphenylene oxide prior to pyrolysis of other plastic components; (d_ sepg. the monomeric constituent of styrene; (e) selecting a second temp. program range of 350-700 deg.C. to cause pyrolysis to a different derived prod. of polyphenylene oxide from the plastic waste and differentially heating the feed stream at the second temp. program range to cause pyrolysis of the plastic into a polyphenylene oxide derived prod.; and (f) sepg. the different polyphenylene oxide derived prod.    Pref. carrier gas is selected fro inert gases, steam, CO2 and process recycle gases. The waste feed then comprises polythene and phenols.    USE/ADVANTAGE -   Recovering styrene and other prods. from waste streams. Fast pyrolysis.    (US5464602-A)      Pyrolysis of a PVC, PET, polystyrene and polyethylene contg. plastic waste feed stream comprises: (a) heating the water to 250-350 deg.C; (b) adding an acid or base catalyst on and oxide or carbonate support; (c) heating at 30 deg.C/min. to pyrolyse PET and PVC; (d) sepg. out terephthalic acid or HCl from (c); (e) heating the effluent from (d) at 30 deg.C/min. to 350-475 deg.C to pyrolyse polystyrene; (f) sepg. out styrene formed in (e); (g) heating the effluent from (f) at 30 deg.C/min. to 475-600 deg.C to pyrolyse polyethylene; and (h) recovering the resulting hydrocarbon.    USE/ADVANTAGE -   Used to recover high value monomers from waste polymers. Controllable pyrolysis of the mixed polymers is achieved.    (US5821553-A)      Using fast pyrolysis in a carrier gas to convert a plastic waste feed stream having a mixed polymeric compsn. comprises (a) selecting a first temp. programme range to cause pyrolysis of the given polymer and its high value monomeric constituent prior to a temp. range that causes pyrolysis of other plastic components; (b) selecting a catalyst and a support and treating the feedstream with this catalyst to affect acid or base catalysed reaction pathways to maximise yield or enhance sepn. of the high value monomeric constituent or high value prod. prior to pyrolysis of other plastic components therein; (d) sepg. the high value monomer constituent or derived high value prod.; (e) selecting a second higher temp. programme range to cause pyrolysis to a different high value monomeric constituent of the plastic waste and differentially heating the feed stream at this higher temp. programme range to cause pyrolysis of the plastic into different high value monomeric constituent or derived prod.; and (f) sepg. the different high value monomeric constituent or derived high value prod..    ADVANTAGE -   This pyrolysis of a complex waste stream of plastics, such as scrap plastics or mixed plastic waste from plants in which plastics are converted into consumer prods., converts the stream into useful high value monomers or other chemicals, by identifying catalyst and temp. conditions that permit decomposition of a given polymer in the presence of others, without decomposition of the other polymers, in order to make it easier to purify the monomer from the easier to decompose plastic. This minimises disposal requirements for nonbiodegradable materials and conserves non-renewable resources    (JP3126735-B2)      Using fast pyrolysis in a carrier gas to convert a plastic waste feed stream having a mixed polymeric compsn. comprises (a) selecting a first temp. programme range to cause pyrolysis of the given polymer and its high value monomeric constituent prior to a temp. range that causes pyrolysis of other plastic components; (b) selecting a catalyst and a support and treating the feedstream with this catalyst to affect acid or base catalysed reaction pathways to maximise yield or enhance sepn. of the high value monomeric constituent or high value prod. prior to pyrolysis of other plastic components therein; (d) sepg. the high value monomer constituent or derived high value prod.; (e) selecting a second higher temp. programme range to cause pyrolysis to a different high value monomeric constituent of the plastic waste and differentially heating the feed stream at this higher temp. programme range to cause pyrolysis of the plastic into different high value monomeric constituent or derived prod.; and (f) sepg. the different high value monomeric constituent or derived high value prod..    ADVANTAGE -   This pyrolysis of a complex waste stream of plastics, such as scrap plastics or mixed plastic waste from plants in which plastics are converted into consumer prods., converts the stream into useful high value monomers or other chemicals, by identifying catalyst and temp. conditions that permit decomposition of a given polymer in the presence of others, without decomposition of the other polymers, in order to make it easier to purify the monomer from the easier to decompose plastic. This minimises disposal requirements for nonbiodegradable materials and conserves non-renewable resources    (EP1122293-A2)      Using fast pyrolysis in a carrier gas to convert a plastic waste feed stream having a mixed polymeric compsn. comprises (a) selecting a first temp. programme range to cause pyrolysis of the given polymer and its high value monomeric constituent prior to a temp. range that causes pyrolysis of other plastic components; (b) selecting a catalyst and a support and treating the feedstream with this catalyst to affect acid or base catalysed reaction pathways to maximise yield or enhance sepn. of the high value monomeric constituent or high value prod. prior to pyrolysis of other plastic components therein; (d) sepg. the high value monomer constituent or derived high value prod.; (e) selecting a second higher temp. programme range to cause pyrolysis to a different high value monomeric constituent of the plastic waste and differentially heating the feed stream at this higher temp. programme range to cause pyrolysis of the plastic into different high value monomeric constituent or derived prod.; and (f) sepg. the different high value monomeric constituent or derived high value prod..    ADVANTAGE -   This pyrolysis of a complex waste stream of plastics, such as scrap plastics or mixed plastic waste from plants in which plastics are converted into consumer prods., converts the stream into useful high value monomers or other chemicals, by identifying catalyst and temp. conditions that permit decomposition of a given polymer in the presence of others, without decomposition of the other polymers, in order to make it easier to purify the monomer from the easier to decompose plastic. This minimises disposal requirements for nonbiodegradable materials and conserves non-renewable resources