BE1008556A3 - Method for treating packaging made of composite maMethod for treating packaging made of composite materials terials - Google Patents

Abstract

Packaging materials shredded into pieces are introduced into the elongatedchamber to form a layer which is displaced in the chamber at a predeterminedrate to be subjected to hot gas flux treatment over a predetermined period oftime, said hot treatment gas being at a temperature of between approximately450 degrees C and 600 degrees C. The hot treatment gas is injected at a numberof points distributed over the length of the treatment chamber.Packaging materials shredded into pieces are introduced into the elongatedchamber to form a layer which is displaced in the chamber at a predeterminedrate to be subjected to hot gas flux treatment over a predetermined period oftime, said hot treatment gas being at a temperature of between approximately450 degrees C and 600 degrees C. The hot treatment gas is injected at anumber of points distributed over the length of the treatment chamber.

Description

       

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  PACKAGING PROCESSING PROCESS
COMPOSITE MATERIAL The present invention relates to the recovery of lost packaging waste and in particular a method of treating packaging made of a mixed material composed of a metallic substance and at least one organic substance with a view to recover the metal and develop the energy potential of the organic substance (s).



  A particular application of the process according to the invention is the treatment of packaging used for packaging food liquids, and made of a composite material composed of a layer of aluminum, a layer of cardboard and a layer of poly - ethylene, for example.



  The aluminum in these packages, and more generally the metal contained in similar composite materials, have appreciable commercial value and their recovery therefore presents a great economic interest coupled with an ecological interest.



  Of course, the recovery of the metal from composite materials such as those which have been mentioned above can only be advantageous if the treatment process is profitable and if the recovered metal is of satisfactory quality so that it can be directly reused.



  The invention provides a solution to this problem by

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 setting a process for treating packaging made of composite material which makes it possible to recover the metal from the composite material.



  Another object of the invention is to recover and also enhance the energy potential of the organic substance or substances of the composite material.



  These objects are achieved according to the invention by means of a treatment method as defined in the claims.



  More particularly, the packages, shredded into pieces, are introduced into an elongated chamber so as to form a ply therein and the aforementioned ply is moved in the chamber at a predetermined speed so as to be subjected to the action of a flow of hot process gas for a predetermined period of time, said hot process gas being at a temperature in the range from about 4500C to 6000C.



  The hot treatment gas is preferably injected into the chamber at several points distributed along the length of the treatment chamber.



  The invention makes it possible to recover the metal in full without any alteration and free of any other substance, the recovered metal having the appearance, chemical composition and physical structure of the metal sheet of the treated packaging.



  In addition, the proposed process makes it possible to recover the energy potential of organic substances in the form of recyclable combustible gas.



  The invention is set out in more detail in what

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 follows using the attached drawing which schematically represents an example of installation for implementing the method according to the invention.



  In accordance with the invention, the packages to be treated are shredded beforehand to form small pieces of 1 cm x 1 cm for example. The pieces are introduced into an elongated enclosure in which they are kept in a gaseous atmosphere with controlled composition and temperature for a predetermined period of time.



  Referring to the appended figure, the reference number 11 designates a shredder (known per se) and the reference number 10 designates an elongated enclosure having an inlet hopper 12 for the introduction of the pieces of packaging to be treated. these are received on a conveyor belt 13 which extends over the length of the enclosure to an outlet hopper 15. The conveyor belt is driven at a predetermined speed of movement in order to ensure sufficient treatment time of the sheet of pieces of packaging 100 that it conveys.



  The conveyor belt 13 is pierced with orifices for the passage of a flow of hot treatment gas with controlled composition injected into compartments 14 formed below the conveyor belt. The treatment gas for example consists of a neutral gas such as nitrogen N2 or combustion fumes, slightly oxygenated. The injection of treatment gas is preferably carried out at several points 16 distributed over the length of the chamber 10. In the drawing we see that the gas injection points 16 are distributed in several compartments 14 under the conveyor belt.

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  The objective of the treatment in the chamber 10 is to ensure suitable pyrolysis of the pieces 100 while effectively controlling a slow combustion of the organic products remaining on the metal of the pieces.



  This slow combustion phenomenon will be called consumption below. To achieve this result, the research carried out by the applicant has shown that the temperature of the treatment gas introduced into the chamber 10 must be in the range from approximately 4500C to 6000C with a slight oxygenation of 1 to 10% approximately depending on the evolution the state of treatment of the pieces on the mat 13. The proportion of oxygen in the injected gas can vary depending on the injection point in the chamber.



  Controlling the temperature and the oxygenation of the treatment gas guarantees control of the exothermic reaction of consumption of organic matter so as to avoid the melting or oxidation of the metal and consequently the poor quality of the metal recovered.



  In order to ensure satisfactory treatment of the ply of pieces of packaging 100, it has been observed that the speed of the treatment gas passing through the ply 100 will preferably be between 0.1 and 0.3 m / s.



  At the end of the residence time in chamber 10, the metal flakes recovered are collected in the outlet hopper 15.



  The treatment gas having passed through the sheet of pieces of packaging 15 is sucked into a filter 17 which separates the steriles therefrom. These are collected in 18. The filtered gas is removed in 19.

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  The treatment method according to the invention is conditioned by several factors.



  A first important factor is the processing temperature. On the one hand, the temperature must be sufficient to ensure the combustion of organic substances without the waste rock from this combustion remaining adhered to the metal. On the other hand, from the first moments of the treatment, the temperature must not be too high in order to avoid too rapid combustion of the organic substances. Indeed, these contain at the moment all of their volatile materials, which are very reactive, thereby causing the creation of hot spots and consequently alteration of the metal.



  The presence of oxygen in the hot process gas is another important factor since on this presence depends the controlled start and advancement of a post-pyrolysis consumption front.



  Another factor in the process is the flow rate of the process gas flow. This flow rate is linked to the thickness and density of the ply of pieces of treated and untreated packaging. With a sheet density of the order of 30 to 200 kg / m3, an actual gas velocity of the order of 0.1 to 0.3 m / s has been found to give excellent results.



  It goes without saying that the flow rate of the treatment gas flow goes hand in hand with the speed of movement of the sheet of treated material, which in short determines the residence time in the treatment chamber. A treatment time of a quarter of an hour to half an hour under the operating conditions mentioned above has been found to be

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 sufficient to give recovered metal flakes whose appearance and quality are the same as those of the metal sheets used in packaging.



  The invention also provides for recovering thermal energy resulting from the pyrolysis of organic matter from the pieces of treated packaging. For this purpose, as mentioned above, the invention proposes to recycle the filtered treatment gas discharged in 19 and to use it as combustible gas.



  For this purpose, the recovered gas is brought into a boiler 20, for example a high temperature, high turbulence and long residence time (TTT) boiler, known per se. This boiler is shown schematically in the figure. In 21 is marked the inlet of the recycled combustible gas, in 22 is marked the fuel intake of a burner and in 23 is marked the secondary air intake. The combustion fumes are evacuated at 24 to the chamber 10. In order to ensure the required temperature of the combustion fumes at the inlet of the treatment chamber 10, a heat exchanger 25 performs the required temperature adjustment. The reference number 26 designates an air heating coil intended for the oxygenation of the treatment gas to be introduced into the chamber 10.

   The coil 27 is used for energy recovery for outdoor use. The fumes are evacuated at 28.


    

Claims (10)

 CLAIMS 1. Process for treating packages made of a composite material composed of a metallic layer and at least one organic layer, characterized in that the packages, shredded into pieces, are introduced into an elongated chamber so as to forming a sheet therein and the aforementioned sheet is moved in the chamber at a predetermined speed so as to be subjected to the action of a flow of hot treatment gas for a predetermined period of time, said hot treatment gas being at a temperature in the range from about 4500C to 6000C. 2. Method according to claim 1, characterized in that the flow of hot treatment gas is injected into the chamber in several places distributed over the length of the treatment chamber. 3. Method according to claim 1 or 2, characterized in that the hot treatment gas consists partly of nitrogen or combustion fumes. 4. Method according to one of claims 1 to 3, characterized in that the hot treatment gas contains oxygen in a proportion of 1 to 10% by volume. 5. Method according to claim 4, characterized in that the proportion of oxygen in the treatment gas varies according to the injection point in the treatment chamber. 6. Method according to one of claims 1 to 5, characterized in that the hot treatment gas is generated in part by the combustion of the gas recovered at the  <Desc / Clms Page number 8>  leaving the aforementioned room. 7. Method according to one of claims 1 to 6, characterized in that the hot treatment gas at the outlet of the chamber is at a temperature of at least 350 C. 8. Installation for treating packaging made of composite material for implementing the method according to any one of claims 1 to 7. 9. Installation according to claim 8, characterized in that it comprises an elongated chamber (10) in which is mounted a conveyor belt (13) and in which are provided several gas injection points (16) distributed over the length of the aforementioned room. 10. Installation according to claim 9, characterized in that the gas injection points (16) open into several compartments (14) formed below the conveyor belt.