Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
  • C10J3/005—Rotary drum or kiln gasifiers
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
  • C10J3/02—Fixed-bed gasification of lump fuel
  • C10J3/06—Continuous processes
  • C10J3/12—Continuous processes using solid heat-carriers
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2200/00—Details of gasification apparatus
  • C10J2200/15—Details of feeding means
  • C10J2200/158—Screws
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0913—Carbonaceous raw material
  • C10J2300/0946—Waste, e.g. MSW, tires, glass, tar sand, peat, paper, lignite, oil shale
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0953—Gasifying agents
  • C10J2300/0956—Air or oxygen enriched air
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0953—Gasifying agents
  • C10J2300/0959—Oxygen
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0983—Additives
  • C10J2300/0993—Inert particles, e.g. as heat exchange medium in a fluidized or moving bed, heat carriers, sand
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/12—Heating the gasifier
  • C10J2300/1223—Heating the gasifier by burners

Definitions

• the present invention relates to the field of recovery and recycling of plastics treated downstream of the segregated collection of municipal solid waste.
• plastics are not homogeneous and do not represent a single material, but are rather composed of different materials with their own chemical and physical characteristics.
• the polymer chosen for each use must in fact meet specific requirements in terms of preservation (protection against air, light) , logistics (efficiency in transport, handling at the points of sale, spaces occupied in homes), and aesthetics (transparency, colours, possibility of applying wording and images) .
• plastics originating from segregated waste collection need to undergo processes of selection for polymer (PET, PE, PP) or family of polymers, in order to be afterwards reintroduced into the market for the production of semi-finished or finished products.
• the residual left over after such selection processes consisting of a mixture of plastics, displays a large heterogeneity that makes it substantially impossible to exploit in the recycling market, which demands homogeneous material sorted by polymer or family of polymers.
• Said mixture of plastics displays a good calorific value, estimable to be between 20 and 30 MJ/kg, above the limit of 13 MJ/kg, which represents the maximum value for landfillable waste (European Directive 1999/31/EC transposed in Italy by Legislative Decree 13/1/2003 n.36) .
• gasification i.e. the thermal treatment of a substance or mixture of substances in the presence of an oxidizing agent in substoichiometric amounts, with the passage from the solid state to a fuel gas, names as synthesis gas or syngas, enables to produce electricity with a greater yield and a lower environmental impact compared to solutions based on combustion alone.
• Said apparatus and procedure can be optimized in order to implement a gasification process based on the specific characteristics of the mix of plastics.
• the present invention contributes to solving the problem of making use of plastics, in particular end-of-life (exhausted) plastic packaging, by providing an alternative solution to landfilling and enabling the production of fuel gas.
• Scope of the process and apparatus of the present invention is to obtain, by conducting and performing the thermal treatment in a particular way, without the input of heat from the outside, fuel gases that can be used in a plant for the combined production of electricity and heat energy.
• the object of the present invention refers to a process for the production of fuel gases obtained from a mixture of plastics, comprising the following operations:
• a combustive agent selected from the group comprising: air, oxygen, nitrogen, argon and combinations thereof;
• fuel gas synthesis gas or syngas
• said fuel gas being composed of the mixture of combustion products and volatile substances not combusted at a temperature in the range of 700- 850°C; unloading and collection of solid residual products, such as ashes.
• the mixture of plastics treated according to the proposed process includes:
• the mixture of plastics, prior to loading in the reactor apparatus, is preferably mechanically pre-treated by grinding with a grinder having a maximum output mesh size in the range between 30 and 60 mm, preferably equal to 50 mm.
• the solid mobile bed of the gasification apparatus has the following characteristics:
• -values of specific heat of the material forming the bed such as to obtain a thermal capacity of the bed in the range between 400 and 2000 kJ/kg, preferably 1000 kJ/kg;
• the elementary unit of the material constituting the bed has a roundness (defined as the ratio between the outer surface of a sphere which has the same volume as a particle of the material forming the bed and the outer surface of the particle itself) of 0.6 to 1, preferably 1, with the maximum size in the range between 10 and 40 mm, preferably 25 mm.
• the ratio between the mass of the mobile solid bed (kg) and the flow rate of the loaded mixture of plastics (kg/hr) is in the range between 3 and 20, preferably 5, and the flow rate of the combustive agent injected into the combustion chamber has an equivalence ratio (defined as the ratio between the amount of oxygen fed and that necessary for stoichiometric combustion of the loaded mixture of plastics) in the range between 0.16 and 0.30.
• the material forming the mobile bed is made with a multiplicity of elements made of metallic or ceramic material.
• the choice between a ceramic bed and metal bed is tied to specific configurations connected to the productivity of the plant; in particular, it is based on such parameters as height, weight of the bed, mass of the solid mobile bed (kg) and the flow rate of the loaded mixture of plastics (kg/hour) .
• the use of bed in ceramic material is preferable.
• the solid mobile bed when values V of the ratio between the mass of the mobile solid bed (kg) and the flow rate of the loaded mixture of plastics (kg/hour) is in the range between 3 and 8 included (3 ⁇ V ⁇ 8 ) , is made of ceramic material, preferably in the form of solid elements, the ceramic material being selected from the group comprising: calcinated bauxite, grounded corundum and tabular alumina.
• the solid mobile bed when values V of the ratio between the mass of the mobile solid bed (kg) and the flow rate of the loaded mixture of plastics (kg/hour) is in the range between 8, excluded, and 20 (8 ⁇ V ⁇ 20), is made of metallic material, preferably in the form of hollow elements, the metallic material being selected from the group comprising: steel, preferably stainless steel, and cast iron .
• a further advantage of the present invention is the formation of a syngas mainly consisting of methane and carbon monoxide, with a low percentage of tar.
• the present invention also refers to an apparatus suitable for carrying out the process according to the invention.
• a further object of the present invention is an apparatus suitable for the production of fuel gas from a mixture of plastics comprising:
• substantially cylindrical chamber (1) rotating around its longitudinal axis of symmetry, optionally inclined downwardly from the inlet section to the outlet section relative to the horizontal plane by an angle comprised between 1 and 3%, with a rotation speed in the range between 0.5 and 3.0 rpm, preferably 1.5 rpm, with a ratio between diameter and length ranging between 0.15 and 0.4, and provided with means able to achieve an internal depression of the chamber between -10 and - 40 Pa; the chamber being partially filled with a mobile solid bed (2) chemically inert towards the mixture of plastics;
• - preheating means (3) consisting, for example, in at least one burner, preferably supplied with methane;
• -supply means for supplying the mixture of plastics, consisting of gravity feeding means, such as, for example, a screw feeder or conveyor belts with a longitudinal distribution over the mobile bed;
• -input and distribution means (5) for the combustive agent consisting preferably in a lance arranged parallel to the axis of longitudinal symmetry of the chamber and having a plurality of nozzles for the emission of the combustive agent toward the mobile bed;
• -discharge means (6) for discharging the solid residue, such as, for example, grids with a mesh having dimensions smaller than the grain size of the material constituting the mobile bed.
• Figure 1 shows a longitudinal section and cross section along the line A-A of one embodiment of the apparatus according to the invention .
• the figure of the cross section of the invention shows the position of the system (5) for introducing the combustive agent, positioned higher than the system (4) for introducing the mixture of plastics.
• the mixture of plastics to be treated according to the process of the present invention has the characteristics indicated in the table below (% by weight) .
• the density in the heap of the mixture of plastics is equal to 115 kg/m 3 .
• the used cylindrical reaction chamber also referred to as a drum, has the following dimensional characteristics:
• the diameter/length ratio of the chamber is thus equal to 0.34.
• the reaction chamber rotates around its own axis, inclined downwardly from the inlet section to the outlet section relative to the horizontal plane by a 1 degree angle, at a speed of 1.5 rpm.
• the screw feeder is positioned inside the reactor so as to ensure a length of the reaction area of 2.65 m.
• the average depression inside the chamber is equal to -30
• the reaction chamber was preheated to a temperature of 900 °C and in such a way the solid mobile bed loaded inside the reactor beforehand was also heated.
• the thermal capacity of the bed is 1055 kJ/kg.
• the ratio between the mass of the solid mobile bed (kg) and the flow rate of the loaded mixture of plastics (kg/hour) is equal to 5.
• a multi-nozzle lance was installed and arranged parallel to the longitudinal axis of symmetry of the drum, so as to inject an overall flow of 83 Nm 3 /h of the combustive mixture composed of air and oxygen, with a total oxygen content of 43%.
• the equivalence ratio is equal to 0.22.
• the combustive mixture is used for the combustion of part of the volatiles previously produced by the physiochemical interaction between the residue and solid mobile bed.
• the usual temperature of the mobile bed in the volatilization area is 540°C and in the remaining part of the reactor is 900°C.
• a fuel gas mixture and a solid residue are obtained as an output from the reactor.
• the extracted fuel gas has a flow rate of 165 Nm 3 /h, at a temperature of 760°C, and a calorific value of 13 MJ/Nm 3 .
• the discharged solid residue has a flow rate of 9.5 kg/h.
• the mixture of plastics to be treated according to the process of the present invention has the characteristics specified in the table below (% by weight) .
• the density in the heap of the mixture of plastics is equal to 104 kg/m3.
• the reaction chamber also referred to as a drum, used according to the present invention, has the following dimensional characteristics:
• the diameter/length ratio of the chamber is thus equal to 0.34.
• the reaction chamber rotates around its own axis, inclined downwardly from the inlet section to the outlet section by 1 degree relative to the horizontal plane, at a speed equal to 1.5 rpm.
• the screw feeder is positioned inside the reactor in such a way as to ensure a length of the reaction area of 2.2 m.
• the average depression inside the chamber is equal to -30
• the reaction chamber was preheated to a temperature of 900
• the thermal capacity of the bed is 490 kJ/kg.
• the ratio between the mass of the solid mobile bed (kg) and the flow rate of the loaded mixture of plastics (kg/hour) is equal to 16.
• a multi-nozzle lance was installed and arranged parallel to the axis of longitudinal symmetry of the drum, so as to inject a flow, at an overall rate of 32 Nm 3 /h, of a combustive mixture composed of air and oxygen, with a total oxygen content of 50%.
• the equivalence ratio is equal to 0.24.
• the combustive mixture is used for the combustion of part of the volatiles previously produced by the physicochemical interaction between residue and solid mobile bed.
• the usual temperature of the mobile bed in the volatilization area is 520°C and in the remaining part of the reactor it is 860°C. A mixture of fuel gas and a solid residue are obtained at the outlet of the reactor.
• the extracted fuel gas has a flow rate of 76.7 Nm 3 /h, at a temperature of 815°C, and a calorific value of 11.3 MJ/Nm 3 .
• the discharged solid residue has a flow rate of 7.5 kg/h.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
• Gasification And Melting Of Waste (AREA)
• Solid Fuels And Fuel-Associated Substances (AREA)

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• 2015
  • 2015-05-26 EP EP15732952.5A patent/EP3149115A1/de not_active Withdrawn
  • 2015-05-26 WO PCT/IB2015/053919 patent/WO2015181713A1/en active Application Filing
  • 2015-05-26 CN CN201580027715.9A patent/CN106471101A/zh active Pending

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