US20010056214A1 - Process and apparatus for the controlled pyrolysis of plastic materials - Google Patents
Process and apparatus for the controlled pyrolysis of plastic materials Download PDFInfo
- Publication number
- US20010056214A1 US20010056214A1 US09/923,383 US92338301A US2001056214A1 US 20010056214 A1 US20010056214 A1 US 20010056214A1 US 92338301 A US92338301 A US 92338301A US 2001056214 A1 US2001056214 A1 US 2001056214A1
- Authority
- US
- United States
- Prior art keywords
- bed
- molten metal
- process according
- fraction
- products
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000004033 plastic Substances 0.000 title claims abstract description 64
- 229920003023 plastic Polymers 0.000 title claims abstract description 64
- 239000000463 material Substances 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims abstract description 51
- 230000008569 process Effects 0.000 title claims abstract description 51
- 238000000197 pyrolysis Methods 0.000 title abstract description 9
- 239000000203 mixture Substances 0.000 claims abstract description 43
- 229930195733 hydrocarbon Natural products 0.000 claims abstract description 27
- 150000002430 hydrocarbons Chemical class 0.000 claims abstract description 27
- 239000004215 Carbon black (E152) Substances 0.000 claims abstract description 9
- 239000002184 metal Substances 0.000 claims description 32
- 229910052751 metal Inorganic materials 0.000 claims description 32
- 238000000227 grinding Methods 0.000 claims description 15
- 238000009833 condensation Methods 0.000 claims description 10
- 230000005494 condensation Effects 0.000 claims description 10
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 9
- 229910052725 zinc Inorganic materials 0.000 claims description 9
- 239000011701 zinc Substances 0.000 claims description 9
- 229910052718 tin Inorganic materials 0.000 claims description 8
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 238000012216 screening Methods 0.000 claims description 6
- 229910052787 antimony Inorganic materials 0.000 claims description 5
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 claims description 5
- 238000007654 immersion Methods 0.000 claims description 5
- 239000007788 liquid Substances 0.000 claims description 5
- 238000002844 melting Methods 0.000 claims description 5
- 230000008018 melting Effects 0.000 claims description 5
- 239000002699 waste material Substances 0.000 claims description 5
- 150000004649 carbonic acid derivatives Chemical class 0.000 claims description 4
- 238000013019 agitation Methods 0.000 claims description 3
- 239000012223 aqueous fraction Substances 0.000 claims description 2
- 238000005119 centrifugation Methods 0.000 claims description 2
- 230000002378 acidificating effect Effects 0.000 claims 5
- 229910052914 metal silicate Inorganic materials 0.000 claims 3
- 238000005201 scrubbing Methods 0.000 claims 1
- 239000003054 catalyst Substances 0.000 abstract description 39
- 238000005336 cracking Methods 0.000 abstract description 33
- 238000002485 combustion reaction Methods 0.000 abstract description 11
- 229920000642 polymer Polymers 0.000 abstract description 10
- 239000010813 municipal solid waste Substances 0.000 abstract description 8
- 239000000047 product Substances 0.000 description 20
- 239000007789 gas Substances 0.000 description 13
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 238000004458 analytical method Methods 0.000 description 9
- 239000002253 acid Substances 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 7
- 150000002739 metals Chemical class 0.000 description 7
- 239000012634 fragment Substances 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- 229910052736 halogen Inorganic materials 0.000 description 5
- 150000002367 halogens Chemical class 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 241000196324 Embryophyta Species 0.000 description 4
- 125000001931 aliphatic group Chemical group 0.000 description 4
- 239000003517 fume Substances 0.000 description 4
- 238000002309 gasification Methods 0.000 description 4
- 238000002329 infrared spectrum Methods 0.000 description 4
- 235000011121 sodium hydroxide Nutrition 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 238000009825 accumulation Methods 0.000 description 3
- 238000009835 boiling Methods 0.000 description 3
- 239000012267 brine Substances 0.000 description 3
- 238000004523 catalytic cracking Methods 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000012932 thermodynamic analysis Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 150000007824 aliphatic compounds Chemical class 0.000 description 2
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000000711 cancerogenic effect Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 231100000315 carcinogenic Toxicity 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000004508 fractional distillation Methods 0.000 description 2
- 239000008241 heterogeneous mixture Substances 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000007363 ring formation reaction Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 2
- 239000004449 solid propellant Substances 0.000 description 2
- 238000004227 thermal cracking Methods 0.000 description 2
- 101150051314 tin-10 gene Proteins 0.000 description 2
- MFEVGQHCNVXMER-UHFFFAOYSA-L 1,3,2$l^{2}-dioxaplumbetan-4-one Chemical compound [Pb+2].[O-]C([O-])=O MFEVGQHCNVXMER-UHFFFAOYSA-L 0.000 description 1
- 239000005995 Aluminium silicate Substances 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229920002430 Fibre-reinforced plastic Polymers 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910000003 Lead carbonate Inorganic materials 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- AMQJEAYHLZJPGS-UHFFFAOYSA-N N-Pentanol Chemical compound CCCCCO AMQJEAYHLZJPGS-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- YKTSYUJCYHOUJP-UHFFFAOYSA-N [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] Chemical compound [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] YKTSYUJCYHOUJP-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- 229910000323 aluminium silicate Inorganic materials 0.000 description 1
- CZJCMXPZSYNVLP-UHFFFAOYSA-N antimony zinc Chemical compound [Zn].[Sb] CZJCMXPZSYNVLP-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000009933 burial Methods 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000009089 cytolysis Effects 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 150000002013 dioxins Chemical class 0.000 description 1
- VDQVEACBQKUUSU-UHFFFAOYSA-M disodium;sulfanide Chemical compound [Na+].[Na+].[SH-] VDQVEACBQKUUSU-UHFFFAOYSA-M 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000003000 extruded plastic Substances 0.000 description 1
- 239000011151 fibre-reinforced plastic Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000007849 furan resin Substances 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 238000013101 initial test Methods 0.000 description 1
- LQBJWKCYZGMFEV-UHFFFAOYSA-N lead tin Chemical compound [Sn].[Pb] LQBJWKCYZGMFEV-UHFFFAOYSA-N 0.000 description 1
- JQJCSZOEVBFDKO-UHFFFAOYSA-N lead zinc Chemical compound [Zn].[Pb] JQJCSZOEVBFDKO-UHFFFAOYSA-N 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000003863 metallic catalyst Substances 0.000 description 1
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 150000008442 polyphenolic compounds Chemical class 0.000 description 1
- 235000013824 polyphenols Nutrition 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 235000011118 potassium hydroxide Nutrition 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 150000003384 small molecules Chemical class 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000011775 sodium fluoride Substances 0.000 description 1
- 229910052979 sodium sulfide Inorganic materials 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- GZCWPZJOEIAXRU-UHFFFAOYSA-N tin zinc Chemical compound [Zn].[Sn] GZCWPZJOEIAXRU-UHFFFAOYSA-N 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 235000019352 zinc silicate Nutrition 0.000 description 1
Images
Classifications
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
- A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
- A62D3/32—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by treatment in molten chemical reagent, e.g. salts or metals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03B9/00—General arrangement of separating plant, e.g. flow sheets
- B03B9/06—General arrangement of separating plant, e.g. flow sheets specially adapted for refuse
- B03B9/061—General arrangement of separating plant, e.g. flow sheets specially adapted for refuse the refuse being industrial
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F8/00—Chemical modification by after-treatment
- C08F8/50—Partial depolymerisation
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
- C10G1/10—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal from rubber or rubber waste
-
- 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
- B29B2017/0424—Specific disintegrating techniques; devices therefor
- B29B2017/0496—Pyrolysing the materials
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2810/00—Chemical modification of a polymer
- C08F2810/10—Chemical modification of a polymer including a reactive processing step which leads, inter alia, to morphological and/or rheological modifications, e.g. visbreaking
-
- 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 relates to a process and an apparatus for the controlled pyrolysis of plastic materials.
- thermodestruction technologies are unsuitable and dangerous due to the fumes generated by combustion.
- Various pyrolysis plants have been started in recent years in an attempt to recover energy-yielding products from plastics; all these plants tend to convert the polymer, by heat emission, into a plurality of products to be used both in combustion to generate electric power and in order to eliminate the acid residues that produce toxic fumes.
- direct combustion entails the forming of carcinogenic products, such as dioxins and furfurans;
- thermodynamic mechanisms have been described in many documents, including Gates, B.C. et al., Chemistry of Catalytic Processes , McGraw-Hill, Inc. (1979) and Pines, H., The Chemistry of Catalytic Hydrocarbon Conversions , Academic Press (1981).
- the principal aim of the invention is the elimination of environmental impact problems, recovery of heat energy and minimal production of screening reject. This aim is achieved by a process and an apparatus organized according to the pyrolysis (cracking) process, of the present invention.
- FIG. 1 is a flowchart of a cracking process for producing hydrocarbons from PVC-free plastic with indicated the main parts of a system for carrying out the process of the invention
- FIG. 2 is a flowchart of a cracking process for producing hydrocarbons from PVC and halogenated plastic
- FIG. 3 is a flowchart of a cracking process for producing hydrocarbons from linear plastics.
- the present invention relates to a process and an apparatus for cracking a polymeric material which comprises a reactor containing a molten catalyst bed and means for introducing said polymeric material in said catalyst bed.
- the catalyst used is typically a metal or a mixture of metals and optionally contains an acid component.
- the process according to the invention is useful for converting a variety of polymers, side-chain plastics, linear-chain plastics and halogenated plastics, such as for example PVC, into hydrocarbon products which are useful for energy production yet avoid the pollution problems associated with the direct combustion of plastic materials.
- the process according to the invention can also be used for cracking mixtures of polymeric materials derived from the sorting of municipal solid waste.
- the materials that can be subjected to cracking are differentiated into (1) side-chain plastics (methyl methacrylate, polyurethanes, furan resins), in which it is possible to reobtain the initial monomer to restore new polymers; (2) linear plastics (PVC, PET, PP), alone or mixed, from which hydrocarbons are obtained which are meant for combustion to produce electric power; and (3) a mixture of plastics derived from the mechanized sorting of municipal solid waste, constituted by a highly differentiated mixture of products ranging from plastics to rubber to paper etcetera.
- side-chain plastics methyl methacrylate, polyurethanes, furan resins
- the hydrocarbons that can be obtained from a pyrolysis (cracking) process must have the following characteristics: (1) high content of products having a low relative molecular mass, which must bum without excessive carbon-containing residues; (2) absolute absence of halogens and acid-derived products; and (3) low content of unsaturated compounds, in order to avoid condensations during storage.
- the catalytic cracking of plastic polymers can be considered as a macromolecular lysis into free radicals, whose composition depends on the following factors: (1) the type of catalyst used in the process; (2) the temperature and time of contact with the catalyst; and (3) the amount of plastic material involved per unit time and with respect to the volume of the catalyst.
- an acid-acting component such as a silicate or a carbonate
- silicate or another compound is added when cracking processes occur with the formation of noncondensable gases, i.e., when the catalyst acts so quickly that it breaks the polymer down into gaseous is units which cannot condense at conventional temperatures (H 2 , CH 3 + , CH 4 , etcetera).
- the optimum temperature of the catalyst was calculated by thermodynamic analysis combined with an infrared spectrum, analyzing the peaks in the infrared spectrum of the products of the gasification of the plastics with time and temperature as variants.
- the catalyst has a melting point of 430° C. or less, preferably 400° C. or less.
- the catalyst is kept at a temperature of 460-550° C., preferably 480-530° C.
- the temperature of the catalyst in the reactor is typically at least 60° C. above its melting point, preferably at least 70° C. above its melting point.
- the catalyst is typically a metal or a mixture of metals.
- said catalyst is chosen from the group that consists of lead, tin, zinc, antimony and mixtures thereof, optionally together with other metals.
- metals and mixtures of metals that can be used in the process according to the invention are lead, a lead-zinc mixture, a lead-tin mixture, a zinc-tin mixture, a lead-zinc-tin mixture, a zinc-antimony mixture, or a lead-copper mixture.
- the zinc is present in the amount of 15-25% by weight, preferably approximately 20% by weight.
- tin is present in the amount of 5-15% by weight, preferably approximately 10% by weight.
- the molten catalyst can also advantageously contain an acid component.
- an acid component are metallic silicates, metallic carbonates and mixtures thereof. More particularly, the acid component can be aluminium silicate or lead carbonate.
- tin, antimony and zinc silicates are effective, although they showed lower yields in initial tests. It should be observed that the above mentioned salts are present in the reactor in the molten state rather than as a heterogeneous mixture.
- the catalyst bed is agitated continuously; agitation is meant to homogenize the temperatures and maintain intimate contact between the catalysts and the reaction products.
- the material to be cracked is introduced in the fluid bed at a depth of generally 2-15 cm. Excellent results were observed when the materials was introduced at a depth of 4-5 cm. The depth depends on the polymer to be treated and on the preset temperature and contact times.
- the carbocation can undergo a plurality of different reactions: it can break down into two fragments, isomerize and produce a form with more side chains, or undergo various cyclizations; in the end, in any case, it loses one proton, restores the activity of the catalyst and migrates to the surface as a gas.
- Separation can be performed by using a particular plate condenser in which the central part of the plates is heated, over approximately 1 ⁇ 3 of the total surface of said plate, to a temperature of 70+/ ⁇ 5° C. and the peripheral part (2 ⁇ 3 of the total surface of said plate) is cooled with water cooled to 5+/ ⁇ 1° C.
- the fraction that condenses at 70° C. represents the fraction designated earlier as a semipolymer, which contains a mixture of products of the cyclization of the aliphatic compounds.
- the fraction that condenses at 8° C. contains short-chain aliphatic products.
- Gas chromatography analyses for the first fraction in fact indicate a mixture of hydrocarbon semipolymers containing 70-120 carbon atoms and, for the second fraction, a mixture of short-chain compounds containing 5-25 carbon atoms.
- the semipolymers can be used in mixtures with paper and rags separated out from municipal solid waste. This possibility allows to provide a mixture with paper and rags which allows to improve the combustion efficiencies of said mixture; bearing in mind that the dry fraction produced by the screening of municipal solid waste, generally composed of 45-50% plastics and 45-50% paper and rags, has an average composition of 45-50% plastics and 45-50% paper and rags, if the paper and rags mixture were used directly as a solid fuel, one could utilize a heating value of 2000-2500 kcal/kg and one would obtain a volume of combustion ash equal to 26-30% of the burnt fraction.
- the cracking process is performed after careful thermodynamic-infrared analysis on the mixture to be cracked.
- Thermodynamic analysis combined with an infrared spectrum is a type of analysis which is well-known to analysts in the field; it consists in analyzing the gasification of an organic substance by means of an infrared spectrum after the substance has been subjected to a rapid change in temperature over a specific time fraction. The tests allow to determine the rate at which the material is fed into the catalyst bed and the amount thereof as a function of the difference of the plastic material used.
- two containment silos are prepared: one is active while the other one is subjected to analysis.
- the silos have a capacity adapted for 24 hours of operation and the material is suitably ground and homogenized, as will become apparent from the following description.
- cracking is performed as follows:
- grinding is performed in two separate steps, divided between a coarse grinding and a final grinding.
- Coarse grinding is performed by a shredding mill, capable of reducing the material to fragments measuring no more than 12 mm, preferably no more than 10 mm, while final grinding is performed by means of a bladed mill capable of reducing the fragments to dimensions of no more than 3 mm, preferably no more than 2 mm.
- the material undergoes immersion screening and drying as described hereinafter.
- coarse grinding the sorted material arriving from the accumulation pit is subjected to grinding by means of a shredding mill whose grilles are organized so as to allow a fragment size of no more than 12 mm, preferably no more than 10 mm.
- immersion screening the material subjected to coarse grinding is sent to a vibrating water-immersion screen.
- the screened material is dried with hot air by means of a cyclone or rotary drier (not shown in FIG. 1), depending on the amount of plastics involved.
- the dried material is sent to grinding by means of a bladed mill, whose grilles must be organized so as to achieve a fragment size of no more than 3 mm, preferably no more than 2 mm.
- the material thus prepared is stored in fiber-reinforced plastic silos (not shown in FIG. 1), whose capacity must be at least equal to 24 hours of processing; for this purpose, at least three containment silos for the mixture to be cracked are prepared, so as to always have the possibility to preset the temperatures and times of the reaction as described hereafter.
- dosage of the material is determined by a thermodynamics/infrared analysis which determines, as a function of the contact time/operating temperature, the amount to be introduced in the reactor in the unit time. This is an extremely important value, since it allows to obtain high yields without producing large amounts of pyrolytic coal; moreover, the analysis identifies the amounts of the simpler carbon/hydrogen products which have the highest heating value.
- Thermodynamic analysis is performed on a mixture of samples taken during the fine grinding step and sample collection ports arranged on the conveyor belt that feeds the storage silo are used.
- Cracking follows a preheating step, during which the dried material is removed by way of a screw-feeder extractor and sent to an extruder which is directly connected to the cracking reactor (each reactor has extruders which operate with a very specific synchronization which depends on the above mentioned analysis); the extruders are fed by way of a screw feeder/piston valve which is meant to provide precise dosage of the amount of product to be introduced in the reactor.
- the extruders constituting practically feeding means for introducing the material into the apparatus of the present invention, bring the material to a plastic state, which allows to inject it into the reactor without difficulty.
- the temperature increase allows to reduce contact times, improving the quality of the obtainable aliphatic hydrocarbons.
- the reactor is filled for 2 ⁇ 3 of its volume with a catalyst maintained in the molten state for example by forced circulation of diathermic oil heated in a suitable central unit.
- the plastic material is injected into the bed of the catalyst and the extruded plastic material, on contact with the catalyst, gasifies in a few seconds; the cracking gases are collected by suction (the entire system operates with a slight negative pressure) by a cyclone (not shown in FIG. 1) which is meant to separate the traces of metals distilled from the cracking gas; these metals are recovered from the bottom of the cyclone and sent to reuse.
- plastics with halogens in a first step the gases that arrive from the cracking reactor are scrubbed in a square tower by circulating a solution of 15% NaOH by weight.
- the top part of the column is cooled by a coil in which brine at a temperature of ⁇ 15° C. is subjected to forced circulation.
- the eluate which contains the salified halogens, all the water-soluble products (methyl alcohol, amyl alcohol, formaldehyde, etcetera) and the insoluble hydrocarbons, is connected in an accumulation reservoir, agitated and kept cool by the brine.
- the eluates are sent to a liquid/liquid centrifuge of the ALFA LAVAL class or the like. Centrifugation separates the aqueous fraction from the fraction composed of (mostly aliphatic) hydrocarbons obtained from cracking.
- the hydrocarbons are collected in a steel accumulation reservoir equipped with a cooling and agitation system to be used as fuel to generate electric power.
- the aqueous part undergoes fractional distillation process in order to separate the halogenated salts from the combustible products.
- the combustible products collected at the top of the distillation column (a perforated-plate column is used) are sent to the hydrocarbon collection reservoir after passing through a tube-nest condenser.
- the entire system must operate with a slight negative pressure (10-15 mm of water head), from the extruders to the condensation column.
- the apparatus must be saturated with nitrogen and at the bottom of the condensation column there must be a collection system for the nitrogen which, before being released into the environment, must be burned in order to eliminate the traces of noncondensables that inevitably form during the process.
- the plastic material which is generally collected after separating municipal solid waste and is therefore a mixture of plastics, is stored in a silo having a capacity equal to 24 hours of operation.
- the material undergoes a first grinding by way of a bladed mill and then a screening in order to separate out fragments measuring more than 2 mm.
- the fraction larger than 2 mm is returned to grinding.
- the smaller fraction (2 mm) is stored in a silo having the same capacity as the first one (24 hours).
- the final storage operation is preceded by drying performed with hot air obtained during the cooling of the separator cyclone, whose task is to separate the cracking coal entrained by the cracking gases.
- the amount of plastic material reserved for the cracking process is removed from the silo that stores the fine fraction (2 mm) by means of a dosage valve or volumetric valve; said amount is always determined by means of the above described thermodynamic-infrared analysis.
- the gases produced in the cracking process are sent to the cyclone in order to separate out the produced coals and are then transferred to a water-cooled condenser. Two products form in this condenser: a noncondensable gas and a liquid constituted by a highly heterogeneous mixture of hydrocarbons.
- the noncondensables are sent to a column for absorption in countercurrent with a 15% alkaline solution of NaOH; said column retains said halogens by chemical reaction between the halogens and the NaOH, forming the respective salts, which are recovered by crystallization.
- the hydrocarbons undergo fractional distillation, which yields three different types of product, specifically: (1) a low-boiling fraction, constituted by a mixture of alcohols and hydrocarbons with low relative molecular mass (C 3 -C 8 ), which are used to maintain reactor heating; (2) a medium fraction (C 5 -C 25 ), which is stored for use in the gas-turbine generators; and (3) a high-boiling fraction (semipolymers) which is used as an additive for the paper and rags, exactly as described above.
Landscapes
- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Medicinal Chemistry (AREA)
- Toxicology (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Wood Science & Technology (AREA)
- Polymers & Plastics (AREA)
- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
Abstract
Description
- This is a Continuation-In-Part of prior pending application U.S. Ser. No. 09/267,343 filed on Mar. 15, 1999.
- The present invention relates to a process and an apparatus for the controlled pyrolysis of plastic materials.
- The growing demand for clean energy and the need to dispose waste which degrades naturally only with difficulty, such as plastics from hospital, municipal and industrial waste, is radically changing the problem of disposal, which can no longer be considered as the more or less uncontrolled burial used so far.
- On the other hand, thermodestruction technologies are unsuitable and dangerous due to the fumes generated by combustion. Various pyrolysis plants have been started in recent years in an attempt to recover energy-yielding products from plastics; all these plants tend to convert the polymer, by heat emission, into a plurality of products to be used both in combustion to generate electric power and in order to eliminate the acid residues that produce toxic fumes.
- The technologies currently used in this field employ high temperatures (500-800° C.) in static and/or rotary furnaces with very long contact times (3-4 min); this entails very high plant costs without an appropriate economic efficiency.
- Various disadvantages are observed:
- 1. direct combustion entails the forming of carcinogenic products, such as dioxins and furfurans;
- 2. any attempts to directly bum the gasification products instead of the residue of the sorting of municipal solid waste (dry fraction constituted by paper, rags and plastics) does not solve the problem of the emission of the above-mentioned carcinogenic fumes, and gasification contributes to an increase in operating costs;
- 3. the presence of plastics such as PVC leads to high corrosion of the combustion equipment, and it is impossible to use high-temperature boilers due to the inevitable corrosion of their tube nest.
- Thermal cracking and catalytic cracking have long been used in refineries for the pyrolysis of organic components having a medium relative molecular mass. The thermodynamic mechanisms have been described in many documents, including Gates, B.C. et al.,Chemistry of Catalytic Processes, McGraw-Hill, Inc. (1979) and Pines, H., The Chemistry of Catalytic Hydrocarbon Conversions, Academic Press (1981).
- The principal aim of the invention is the elimination of environmental impact problems, recovery of heat energy and minimal production of screening reject. This aim is achieved by a process and an apparatus organized according to the pyrolysis (cracking) process, of the present invention.
- Further characteristics and advantages will become apparent from the description of a preferred embodiment of the process and apparatus for the controlled pyrolysis of plastic materials, illustrated only by way of non-limitative example in the accompanying drawing figures, wherein:
- FIG. 1 is a flowchart of a cracking process for producing hydrocarbons from PVC-free plastic with indicated the main parts of a system for carrying out the process of the invention;
- FIG. 2 is a flowchart of a cracking process for producing hydrocarbons from PVC and halogenated plastic;
- FIG. 3 is a flowchart of a cracking process for producing hydrocarbons from linear plastics.
- In its broadest aspect, the present invention relates to a process and an apparatus for cracking a polymeric material which comprises a reactor containing a molten catalyst bed and means for introducing said polymeric material in said catalyst bed.
- As will become apparent from the following detailed description of the invention, the catalyst used is typically a metal or a mixture of metals and optionally contains an acid component.
- The process according to the invention is useful for converting a variety of polymers, side-chain plastics, linear-chain plastics and halogenated plastics, such as for example PVC, into hydrocarbon products which are useful for energy production yet avoid the pollution problems associated with the direct combustion of plastic materials. The process according to the invention can also be used for cracking mixtures of polymeric materials derived from the sorting of municipal solid waste.
- In the pyrolysis of organic components with a high relative molecular mass, such as plastics, it can be specified that the treatment is a combination of two technologies, namely thermal cracking and catalytic cracking.
- According to the present invention, the materials that can be subjected to cracking are differentiated into (1) side-chain plastics (methyl methacrylate, polyurethanes, furan resins), in which it is possible to reobtain the initial monomer to restore new polymers; (2) linear plastics (PVC, PET, PP), alone or mixed, from which hydrocarbons are obtained which are meant for combustion to produce electric power; and (3) a mixture of plastics derived from the mechanized sorting of municipal solid waste, constituted by a highly differentiated mixture of products ranging from plastics to rubber to paper etcetera.
- When dealing with a system for cracking non-uniform plastic (a mixture of various types of plastic), the result is not just aliphatic hydrocarbons but a mixture of hydrocarbons. When dealing with pure plastics (of a single type), it is not convenient to use them for the production of hydrocarbons; rather, it is convenient to act so as to obtain new monomers or directly reuse the plastics.
- The hydrocarbons that can be obtained from a pyrolysis (cracking) process must have the following characteristics: (1) high content of products having a low relative molecular mass, which must bum without excessive carbon-containing residues; (2) absolute absence of halogens and acid-derived products; and (3) low content of unsaturated compounds, in order to avoid condensations during storage.
- This aim, this object and others which will become apparent hereinafter are achieved by an apparatus which comprises a reactor which contains a bed of catalyst in the molten state.
- The catalytic cracking of plastic polymers can be considered as a macromolecular lysis into free radicals, whose composition depends on the following factors: (1) the type of catalyst used in the process; (2) the temperature and time of contact with the catalyst; and (3) the amount of plastic material involved per unit time and with respect to the volume of the catalyst.
- The characteristics that catalysts must have are an electronegative power capable of breaking down a polymeric compound into smaller molecular fractions; their validity has been determined experimentally and the most valid catalysts are described hereinafter.
- The addition of an acid-acting component, such as a silicate or a carbonate, is always determined experimentally; usually, silicate or another compound is added when cracking processes occur with the formation of noncondensable gases, i.e., when the catalyst acts so quickly that it breaks the polymer down into gaseous is units which cannot condense at conventional temperatures (H2, CH3 +, CH4, etcetera).
- The optimum temperature of the catalyst was calculated by thermodynamic analysis combined with an infrared spectrum, analyzing the peaks in the infrared spectrum of the products of the gasification of the plastics with time and temperature as variants.
- Typically, the catalyst has a melting point of 430° C. or less, preferably 400° C. or less. In the process, the catalyst is kept at a temperature of 460-550° C., preferably 480-530° C. The temperature of the catalyst in the reactor is typically at least 60° C. above its melting point, preferably at least 70° C. above its melting point.
- As clearly shown by the examples, the catalyst is typically a metal or a mixture of metals. Preferably, said catalyst is chosen from the group that consists of lead, tin, zinc, antimony and mixtures thereof, optionally together with other metals. Examples of metals and mixtures of metals that can be used in the process according to the invention are lead, a lead-zinc mixture, a lead-tin mixture, a zinc-tin mixture, a lead-zinc-tin mixture, a zinc-antimony mixture, or a lead-copper mixture.
- In an example of a useful catalyst mixture which comprises lead and zinc, the zinc is present in the amount of 15-25% by weight, preferably approximately 20% by weight. In an example of a useful catalyst mixture comprising lead and tin, tin is present in the amount of 5-15% by weight, preferably approximately 10% by weight.
- The molten catalyst can also advantageously contain an acid component. Examples of an acid component are metallic silicates, metallic carbonates and mixtures thereof. More particularly, the acid component can be aluminium silicate or lead carbonate. In this regard, tin, antimony and zinc silicates are effective, although they showed lower yields in initial tests. It should be observed that the above mentioned salts are present in the reactor in the molten state rather than as a heterogeneous mixture.
- Usually, the catalyst bed is agitated continuously; agitation is meant to homogenize the temperatures and maintain intimate contact between the catalysts and the reaction products. The material to be cracked is introduced in the fluid bed at a depth of generally 2-15 cm. Excellent results were observed when the materials was introduced at a depth of 4-5 cm. The depth depends on the polymer to be treated and on the preset temperature and contact times.
- Experience acquired in pilot plants has shown that the amount of plastic material, in kilograms, converted per liter of catalyst per unit time (24 hours) reached values between 12 and 15. The process can obviously be optimized and better yields are certainly within the grasp of the skilled in the art.
- Although there is to intention of being limited by theory, the reactions that can be hypothesized are as follows:
- (1) in the first stage (immersion of the polymers in the molten bed of the catalyst), the polymer breaks down in the C-C bonds and the resulting radicals are fixed to the catalyst; during this step, a series of electrons is released, consequently forming aliphatic compounds.
- (2) during the first-step reaction, the catalyst assumes acid characteristics; the aliphatic components migrate onto this surface, assume one proton and are converted into carbocations.
- (3) the carbocation can undergo a plurality of different reactions: it can break down into two fragments, isomerize and produce a form with more side chains, or undergo various cyclizations; in the end, in any case, it loses one proton, restores the activity of the catalyst and migrates to the surface as a gas.
- By appropriately varying the temperatures of the catalyst, the contact times and the charges of plastic material in the unit time it is possible to obtain semipolymers together with the hydrocarbons. The semipolymers can be collected in a fraction which condenses at 70+/−5° C., while the hydrocarbons are collected in another fraction which condenses at 9+/−2° C.
- Separation can be performed by using a particular plate condenser in which the central part of the plates is heated, over approximately ⅓ of the total surface of said plate, to a temperature of 70+/−5° C. and the peripheral part (⅔ of the total surface of said plate) is cooled with water cooled to 5+/−1° C.
- The fraction that condenses at 70° C. represents the fraction designated earlier as a semipolymer, which contains a mixture of products of the cyclization of the aliphatic compounds. The fraction that condenses at 8° C. contains short-chain aliphatic products. Gas chromatography analyses for the first fraction in fact indicate a mixture of hydrocarbon semipolymers containing 70-120 carbon atoms and, for the second fraction, a mixture of short-chain compounds containing 5-25 carbon atoms.
- The semipolymers can be used in mixtures with paper and rags separated out from municipal solid waste. This possibility allows to provide a mixture with paper and rags which allows to improve the combustion efficiencies of said mixture; bearing in mind that the dry fraction produced by the screening of municipal solid waste, generally composed of 45-50% plastics and 45-50% paper and rags, has an average composition of 45-50% plastics and 45-50% paper and rags, if the paper and rags mixture were used directly as a solid fuel, one could utilize a heating value of 2000-2500 kcal/kg and one would obtain a volume of combustion ash equal to 26-30% of the burnt fraction.
- The addition of 50% of the semipolymers obtained from the cracking process would raise the heating value of the paper-rags mixture to 5500-6000 kcal/kg; since these semipolymers, by way of their chemical configuration, are oxygen carriers, one would obtain a decrease in ash from 26-30% to a maximum of 4%.
- On the basis of these experimental data, it has been thought to hypothetically outline the electric power generation stations which would operate with waste plastic material. The hydrocarbons (liquid phase of the cracking process), which are preferably largely aliphatic, are sent to an electric generator (gas-turbine) whose delivered power rating is 60% of the required power; the hot fumes of combustion are used as a cogeneration factor to heat water. The heat exchange process occurs in a boiler which is controlled by a feeder system for the combustion of solid fuels, i.e., the mixture of paper, rags and semipolymers, so that the water is brought to the temperature of 480° C. and the vapors are used for a high-pressure turbine.
- Since high-pressure turbines have limited elasticity in terms of the possibility of variations with respect to the potential of delivered energy, it is possible to utilize the variation in energy with the gas-turbine units; accordingly, when it is necessary to reduce energy consumption (nighttime or plant shutdowns) it is possible to resort to gas-turbine units and have steam available for other industrial uses.
- The cracking processes according to the invention are illustrated in the flowcharts of FIGS.1-3.
- Depending on the differentiation and heterogeneous nature of the plastic materials derived from the sorting of municipal solid waste and from plastics in general, the cracking process is performed after careful thermodynamic-infrared analysis on the mixture to be cracked.
- Thermodynamic analysis combined with an infrared spectrum is a type of analysis which is well-known to analysts in the field; it consists in analyzing the gasification of an organic substance by means of an infrared spectrum after the substance has been subjected to a rapid change in temperature over a specific time fraction. The tests allow to determine the rate at which the material is fed into the catalyst bed and the amount thereof as a function of the difference of the plastic material used.
- In order to perform the cracking process, two containment silos are prepared: one is active while the other one is subjected to analysis. The silos have a capacity adapted for 24 hours of operation and the material is suitably ground and homogenized, as will become apparent from the following description.
- With reference to the flowchart shown in FIG. 1, cracking is performed as follows:
- During the pretreatment step, grinding is performed in two separate steps, divided between a coarse grinding and a final grinding. Coarse grinding is performed by a shredding mill, capable of reducing the material to fragments measuring no more than 12 mm, preferably no more than 10 mm, while final grinding is performed by means of a bladed mill capable of reducing the fragments to dimensions of no more than 3 mm, preferably no more than 2 mm.
- Between the first and the second grinding, the material undergoes immersion screening and drying as described hereinafter. During coarse grinding, the sorted material arriving from the accumulation pit is subjected to grinding by means of a shredding mill whose grilles are organized so as to allow a fragment size of no more than 12 mm, preferably no more than 10 mm. In the immersion screening, the material subjected to coarse grinding is sent to a vibrating water-immersion screen. By utilizing the difference in relative density between halogenated plastics and other plastics, a distinct separation is achieved and the halogenated plastics are collected at the bottom of the screen, while the lighter ones are entrained by the motion of the water and are recovered on the upper part of the screen. The screened material is dried with hot air by means of a cyclone or rotary drier (not shown in FIG. 1), depending on the amount of plastics involved. In order to achieve fine grinding, the dried material is sent to grinding by means of a bladed mill, whose grilles must be organized so as to achieve a fragment size of no more than 3 mm, preferably no more than 2 mm.
- The material thus prepared is stored in fiber-reinforced plastic silos (not shown in FIG. 1), whose capacity must be at least equal to 24 hours of processing; for this purpose, at least three containment silos for the mixture to be cracked are prepared, so as to always have the possibility to preset the temperatures and times of the reaction as described hereafter.
- During cracking, dosage of the material is determined by a thermodynamics/infrared analysis which determines, as a function of the contact time/operating temperature, the amount to be introduced in the reactor in the unit time. This is an extremely important value, since it allows to obtain high yields without producing large amounts of pyrolytic coal; moreover, the analysis identifies the amounts of the simpler carbon/hydrogen products which have the highest heating value.
- Thermodynamic analysis is performed on a mixture of samples taken during the fine grinding step and sample collection ports arranged on the conveyor belt that feeds the storage silo are used.
- Cracking follows a preheating step, during which the dried material is removed by way of a screw-feeder extractor and sent to an extruder which is directly connected to the cracking reactor (each reactor has extruders which operate with a very specific synchronization which depends on the above mentioned analysis); the extruders are fed by way of a screw feeder/piston valve which is meant to provide precise dosage of the amount of product to be introduced in the reactor. The extruders, constituting practically feeding means for introducing the material into the apparatus of the present invention, bring the material to a plastic state, which allows to inject it into the reactor without difficulty. The temperature increase allows to reduce contact times, improving the quality of the obtainable aliphatic hydrocarbons.
- Cracking occurs in a stainless steel reactor, for example of the 18/8/2 type, which must be kept at a temperature which avoids unwanted condensation under the ceiling of the reactor (i.e., in the part that is not occupied by the catalyst; approximately ⅓ of the volume of the reactor). The temperature of the reactor is maintained by forced circulation of diathermic oil or with other heating sources, but avoiding the use of flame heating in order to avoid fire hazards. As regards the temperature of the free ceiling of the reactor, it is usually kept at 320-430° C.
- The reactor is filled for ⅔ of its volume with a catalyst maintained in the molten state for example by forced circulation of diathermic oil heated in a suitable central unit.
- The plastic material is injected into the bed of the catalyst and the extruded plastic material, on contact with the catalyst, gasifies in a few seconds; the cracking gases are collected by suction (the entire system operates with a slight negative pressure) by a cyclone (not shown in FIG. 1) which is meant to separate the traces of metals distilled from the cracking gas; these metals are recovered from the bottom of the cyclone and sent to reuse.
- The gases, separated from the metallic parts, undergo two separate condensation processes which depend on the type of plastic being cracked.
- As regards plastics with halogens (see FIG. 2), in a first step the gases that arrive from the cracking reactor are scrubbed in a square tower by circulating a solution of 15% NaOH by weight. The top part of the column is cooled by a coil in which brine at a temperature of −15° C. is subjected to forced circulation. The eluate, which contains the salified halogens, all the water-soluble products (methyl alcohol, amyl alcohol, formaldehyde, etcetera) and the insoluble hydrocarbons, is connected in an accumulation reservoir, agitated and kept cool by the brine.
- During a second step, the eluates are sent to a liquid/liquid centrifuge of the ALFA LAVAL class or the like. Centrifugation separates the aqueous fraction from the fraction composed of (mostly aliphatic) hydrocarbons obtained from cracking. The hydrocarbons are collected in a steel accumulation reservoir equipped with a cooling and agitation system to be used as fuel to generate electric power. The aqueous part undergoes fractional distillation process in order to separate the halogenated salts from the combustible products. The combustible products collected at the top of the distillation column (a perforated-plate column is used) are sent to the hydrocarbon collection reservoir after passing through a tube-nest condenser.
- In the case of halogen-free plastics (see FIG. 1), the gases that arrive from the cracking reactor are transferred directly to the condensation column and are therefore condensed with the cracking hydrocarbons, which are kept cool by means of a brine heat exchanger and stored in an agitated and cooled reservoir.
- The entire system must operate with a slight negative pressure (10-15 mm of water head), from the extruders to the condensation column. The apparatus must be saturated with nitrogen and at the bottom of the condensation column there must be a collection system for the nitrogen which, before being released into the environment, must be burned in order to eliminate the traces of noncondensables that inevitably form during the process.
- With reference to FIG. 3, the plastic material, which is generally collected after separating municipal solid waste and is therefore a mixture of plastics, is stored in a silo having a capacity equal to 24 hours of operation. The material undergoes a first grinding by way of a bladed mill and then a screening in order to separate out fragments measuring more than 2 mm. The fraction larger than 2 mm is returned to grinding. The smaller fraction (2 mm) is stored in a silo having the same capacity as the first one (24 hours). The final storage operation is preceded by drying performed with hot air obtained during the cooling of the separator cyclone, whose task is to separate the cracking coal entrained by the cracking gases. The amount of plastic material reserved for the cracking process is removed from the silo that stores the fine fraction (2 mm) by means of a dosage valve or volumetric valve; said amount is always determined by means of the above described thermodynamic-infrared analysis. The gases produced in the cracking process are sent to the cyclone in order to separate out the produced coals and are then transferred to a water-cooled condenser. Two products form in this condenser: a noncondensable gas and a liquid constituted by a highly heterogeneous mixture of hydrocarbons. The noncondensables are sent to a column for absorption in countercurrent with a 15% alkaline solution of NaOH; said column retains said halogens by chemical reaction between the halogens and the NaOH, forming the respective salts, which are recovered by crystallization. The hydrocarbons undergo fractional distillation, which yields three different types of product, specifically: (1) a low-boiling fraction, constituted by a mixture of alcohols and hydrocarbons with low relative molecular mass (C3-C8), which are used to maintain reactor heating; (2) a medium fraction (C5-C25), which is stored for use in the gas-turbine generators; and (3) a high-boiling fraction (semipolymers) which is used as an additive for the paper and rags, exactly as described above.
- Although the reactions for the formation of the hydrocarbons and of the small molecules can be hypothesized only after careful analysis of the resulting products, it can be said that the noncondensable gases are as follows:
- H2S; CH4; N2; NH3; HCl; HF; traces of CO2 and, by entrainment, C2H5OH and low-boiling components which can be fully blocked if rapid cooling with low temperatures (5-7° C.) is performed.
- The above listed gases must therefore first undergo absorption in a removal tower in an alkaline environment (caustic soda or caustic potash). The H2S, NH3, HCl, HF and CO2 gases are converted into Na2S, NH4OH, NaCl, NaF and Na2CO3, respectively.
- The other components, i.e., CH4, C2H5OH and the entrainment products, are transferred to a torch because they are flammable and are converted into CO2 and H2O.
- On the basis of the experience acquired in pilot plants, the catalysts that are particularly suitable for cracking plastic materials are listed in the following table. In examples 1-6, the percentage composition of the metallic catalysts and the percentage composition of the plastic materials are expressed by weight.
- The disclosures in Italian Patent Application No. MI98A000581 from which this application claims priority are incorporated herein by reference.
Catalyst temp- Plastic material Catalyst Catalyst Plastic erature quantity (Kg)/ volume Ex. type material (° C.) time unit (24 h) (1) 1 Lead MTAM, 480 190-200 15 polyphenols 12 Lead PE2 500 190-200 15 3 Lead 80%- PET3 490 190-200 15 Zinc 20% 4 Lead 90%- PP4 490 200-220 15 Tin 10% 5 Lead 70%- MTAM 30% 500 220 15 Zinc 20%- PE 35% Tin 10% PP 20 % PET 15% 6 Lead 80%- RDF5 530 220 15 Zinc 20% # generally composed of 45-50% plastic and 45-50% paper and rags.
Claims (22)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/923,383 US6423878B2 (en) | 1998-03-20 | 2001-08-08 | Process and apparatus for the controlled pyrolysis of plastic materials |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ITMI98A000581 | 1998-03-20 | ||
ITMI980581 IT1298773B1 (en) | 1998-03-20 | 1998-03-20 | Conversion of waste polymeric materials into products useful for energy production by bringing the material into plastic state, immersing the material in its plastic state in molten metal bed, and collecting the gaseous products |
ITMI98A0581 | 1998-03-20 | ||
US26734399A | 1999-03-15 | 1999-03-15 | |
US09/923,383 US6423878B2 (en) | 1998-03-20 | 2001-08-08 | Process and apparatus for the controlled pyrolysis of plastic materials |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US26734399A Continuation-In-Part | 1998-03-20 | 1999-03-15 |
Publications (2)
Publication Number | Publication Date |
---|---|
US20010056214A1 true US20010056214A1 (en) | 2001-12-27 |
US6423878B2 US6423878B2 (en) | 2002-07-23 |
Family
ID=26331574
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/923,383 Expired - Fee Related US6423878B2 (en) | 1998-03-20 | 2001-08-08 | Process and apparatus for the controlled pyrolysis of plastic materials |
Country Status (1)
Country | Link |
---|---|
US (1) | US6423878B2 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005097448A1 (en) * | 2004-04-06 | 2005-10-20 | Remigiusz Eliasz | A method and a plant for continuous processing waste plastic materials into a hydrocarbon mixture |
EP2878649A1 (en) * | 2013-12-02 | 2015-06-03 | EVP Technology LLC. USA | Apparatus for pyrolizing waste plastic into fuel |
CN108884265A (en) * | 2016-03-31 | 2018-11-23 | 霍尼韦尔国际公司 | The method for producing polyolefin-wax product |
WO2019003253A1 (en) * | 2017-06-28 | 2019-01-03 | Biorenova Societa' Per Azioni | Process for the thermo-catalytic conversion of polymeric materials |
CN110404664A (en) * | 2019-08-09 | 2019-11-05 | 郑州中科新兴产业技术研究院 | A kind of method that low-grade tin-iron mine throws tail in advance |
KR20220033065A (en) * | 2020-09-07 | 2022-03-16 | 한국화학연구원 | Method of Treating Organic Wastes Using Catalyst Pyrolysis |
TWI821503B (en) * | 2020-01-15 | 2023-11-11 | 隆順綠能科技股份有限公司 | Raw material sorting system and method for solid recovered fuel |
Families Citing this family (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
PL188936B1 (en) * | 1999-04-26 | 2005-05-31 | Zmuda Henryk | Method of converting polyolefinic waste materials into hydrocarbons and plant therefor |
US20030187311A1 (en) * | 2002-03-29 | 2003-10-02 | Barvincak James P. | Method of separating and converting hydrocarbon composites and polymer materials |
US7757863B2 (en) | 2003-11-17 | 2010-07-20 | Casella Waste Systems, Inc. | Systems and methods for glass recycling at a beneficiator and/or a material recovery facility |
US7264124B2 (en) | 2003-11-17 | 2007-09-04 | Casella Waste Systems, Inc. | Systems and methods for sorting recyclables at a material recovery facility |
AU2005306872A1 (en) | 2004-11-12 | 2006-05-26 | Casella Waste Systems, Inc. | System for and method mixed-color cullet characterization and certification, and providing contaminant-free, uniformly colored mixed color cullet |
CN2878390Y (en) * | 2006-04-07 | 2007-03-14 | 王新明 | Multi-functional full automatic remote constant temperature heat supply cracking device for waste and old tyre |
US8459466B2 (en) | 2007-05-23 | 2013-06-11 | Re Community Energy, Llc | Systems and methods for optimizing a single-stream materials recovery facility |
US7626062B2 (en) * | 2007-07-31 | 2009-12-01 | Carner William E | System and method for recycling plastics |
CN104593114A (en) * | 2008-06-26 | 2015-05-06 | 谐和能源有限责任公司 | Engineered Fuel Feed Stock |
CN104498098A (en) | 2008-06-26 | 2015-04-08 | 谐和能源有限责任公司 | Engineered Fuel Feed Stock Useful For Displacement Of Coal In Coal Firing Plants |
US8444721B2 (en) | 2008-06-26 | 2013-05-21 | Re Community Energy, Llc | Engineered fuel feed stock |
CA2790678A1 (en) | 2009-12-22 | 2011-06-30 | Re Community Energy, Llc | Sorbent containing engineered fuel feed stocks |
CN104364356B (en) | 2012-01-26 | 2017-09-12 | 谐和能源有限责任公司 | Alleviate unwanted combustion emission using the adsorbent containing engineering fuel feedstocks |
US9365775B1 (en) | 2014-06-27 | 2016-06-14 | Yags, Llc | Waste recycling system |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3996022A (en) | 1974-05-17 | 1976-12-07 | Tennessee Valley Authority | Conversion of waste rubber to fuel and other useful products |
US3974206A (en) | 1974-07-09 | 1976-08-10 | Mitsubishi Gas Chemical Company, Inc. | Process for the thermal decomposition of thermoplastic resins with a heat transfer medium |
DE4234385A1 (en) | 1992-10-06 | 1994-04-07 | Formex Trading Gmbh | Process for the pyrolysis of organic substances |
US5395405A (en) | 1993-04-12 | 1995-03-07 | Molten Metal Technology, Inc. | Method for producing hydrocarbon gas from waste |
US5629464A (en) | 1993-12-23 | 1997-05-13 | Molten Metal Technology, Inc. | Method for forming unsaturated organics from organic-containing feed by employing a Bronsted acid |
US5543558A (en) | 1993-12-23 | 1996-08-06 | Molten Metal Technology, Inc. | Method for producing unsaturated organics from organic-containing feeds |
-
2001
- 2001-08-08 US US09/923,383 patent/US6423878B2/en not_active Expired - Fee Related
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005097448A1 (en) * | 2004-04-06 | 2005-10-20 | Remigiusz Eliasz | A method and a plant for continuous processing waste plastic materials into a hydrocarbon mixture |
EP2878649A1 (en) * | 2013-12-02 | 2015-06-03 | EVP Technology LLC. USA | Apparatus for pyrolizing waste plastic into fuel |
CN108884265A (en) * | 2016-03-31 | 2018-11-23 | 霍尼韦尔国际公司 | The method for producing polyolefin-wax product |
EP3436510A4 (en) * | 2016-03-31 | 2019-09-04 | Honeywell International Inc. | Methods of producing a polyolefin wax product |
WO2019003253A1 (en) * | 2017-06-28 | 2019-01-03 | Biorenova Societa' Per Azioni | Process for the thermo-catalytic conversion of polymeric materials |
US11220633B2 (en) | 2017-06-28 | 2022-01-11 | Biorenova Societa' Per Azioni | Process for the thermo-catalytic conversion of polymeric materials |
CN110404664A (en) * | 2019-08-09 | 2019-11-05 | 郑州中科新兴产业技术研究院 | A kind of method that low-grade tin-iron mine throws tail in advance |
TWI821503B (en) * | 2020-01-15 | 2023-11-11 | 隆順綠能科技股份有限公司 | Raw material sorting system and method for solid recovered fuel |
KR20220033065A (en) * | 2020-09-07 | 2022-03-16 | 한국화학연구원 | Method of Treating Organic Wastes Using Catalyst Pyrolysis |
KR102669580B1 (en) * | 2020-09-07 | 2024-05-29 | 한국화학연구원 | Method of Treating Organic Wastes Using Catalyst Pyrolysis |
Also Published As
Publication number | Publication date |
---|---|
US6423878B2 (en) | 2002-07-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6423878B2 (en) | Process and apparatus for the controlled pyrolysis of plastic materials | |
Chen et al. | Pyrolysis technologies for municipal solid waste: a review | |
FI85597C (en) | FOERFARANDE FOER UTVINNING AV ANVAENDBAR GAS UR AVFALL. | |
CN1141360C (en) | Energy efficient liquefaction of biomaterials by thermolysis | |
US8312821B2 (en) | Waste-tire recycling system | |
KR20120004437A (en) | Method for producing biomass charcoal and device for producing biomass charcoal to be used therefor | |
RU2621097C2 (en) | Device for thermal destruction of waste from polyethylene and polypropylene | |
WO2001005910A1 (en) | Process and apparatus for producing combustible gas from carbonaceous waste | |
CN111750358B (en) | Waste plastic green oiling technology embedded garbage incineration method | |
KR20010031507A (en) | Method of treating resin or organic compound, or waste plastics containing them | |
CN108728140B (en) | Organic hazardous waste low-temperature pyrolysis power generation system | |
JP2012224829A (en) | Pyrolysis system, and method for producing pyrolytic oil | |
Lei et al. | Investigation on thermal dechlorination and catalytic pyrolysis in a continuous process for liquid fuel recovery from mixed plastic wastes | |
EP3312223B1 (en) | Method for thermally decomposing polyethylene and polypropylene waste | |
CN101186836B (en) | Method for removing tar oil from gasified combustible gas by using waste rubber and plastic crack oil | |
EP2674472A1 (en) | The method for conducting of a pyrolysis process of waste plastics and/or rubber and/or organic wastes and the use of a chemical modifier in the method | |
EP2834323A1 (en) | System and method for converting plastic/rubber to hydrocarbon fuel by thermo-catalytic process | |
KR101599358B1 (en) | Apparatus for manufacturing bio-oil being able to recycle undecomposed biomass and the method thereof | |
KR20190131208A (en) | Apparatus comprising pyrolysis-products seperator for recycling mixture of plastics comprising polyvinyl chloride and method for recycling mixture of plastics comprising polyvinyl chloride using the same | |
Yongrong et al. | Technical advance on the pyrolysis of used tires in China | |
US11952540B2 (en) | Method and apparatus for hydrocracking mineralized refuse pyrolysis oil | |
Daniyan et al. | A framework for the production of renewable energy from waste tyre pyrolysis | |
KR20180138188A (en) | Recovery method of d-limonene by fast pyrolysis of waste tire and pyrolysis oil distillation and oil thereof | |
KR20010067332A (en) | Process and plant for processing liquid and/or solid organic waste substances | |
ITMI980581A1 (en) | PROCESS AND PLANT FOR THE CONTROLLED PYROLYSIS OF PLASTIC MATERIALS |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
FPAY | Fee payment |
Year of fee payment: 4 |
|
AS | Assignment |
Owner name: ZENIT - ZERO EMISSION NO IMPACT TECHNOLOGY SOCIETA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:RICCARDO, REVERSO;REEL/FRAME:022495/0613 Effective date: 20090320 |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
FEPP | Fee payment procedure |
Free format text: PAT HOLDER NO LONGER CLAIMS SMALL ENTITY STATUS, ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: STOL); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Free format text: PAT HOLDER CLAIMS SMALL ENTITY STATUS, ENTITY STATUS SET TO SMALL (ORIGINAL EVENT CODE: LTOS); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
AS | Assignment |
Owner name: FENIT S.P.A., ITALY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ZENIT - ZERO EMISSION NO IMPACT TECHNOLOGY SOCIETA' A RESPONSABILITA' LIMITATA IN SHORT ZENIT S.R.L.;REEL/FRAME:031856/0633 Effective date: 20120724 |
|
REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20140723 |