FR2795344A1 - disposal of mixed plastic packaging, etc by pulverising, homogenising and then burning - Google Patents

Abstract

Mixed plastics are treated by pulverising, homogenising and then burning them The plastics may be ground to powder and then homogenised in a silo to produce a material with a grain size \- 1 mm. This is entrained with pressurised air to produce a combustible jet.

Description

 PROCESS FOR PROCESSING MIXED PLASTIC MATERIALS The present invention relates to a process for the treatment of mixed plastics in fuels with controlled characteristics.

Thermoplastics are becoming more and more important in today's world and have often replaced traditional materials such as wood, metal or natural textiles because of the advantages of thermoforming or injection molding. They have found a field of choice in disposable products and especially packaging. Moreover, for mechanical reasons or presentation, the products manufactured, made of plastics, include more and more different plastics.

These mixed plastics can not be recycled because of their different characteristics. However, because of their characteristics and their very long life, apart from biodegradable thermoplastics, it is necessary to eliminate them in order to protect the environment. This operation becomes unavoidable with the arrival of numerous plastic complexes as they are developed in the coextrusion and the bi-material injection as well as in all the household appliances in which there are several polymers and all the furniture. end of life.

A first object of the invention is to overcome this disadvantage and to allow the proper destruction of said mixed materials.

According to the invention, the process for treating the mixed plastics is characterized in that it consists in reducing the materials in pulverulent form and then burning them. The object of this process consists in treating all combustible materials of various origins in pulverulent materials intended to be burned in facilities provided for this purpose on which three points are to be examined: fireplace (the burner); the mixer and the flue gas treatment.

This process makes it possible to valorize these materials by the supply of heat energy and this according to the needs at the moment considered. It should be noted that the calorific value of many plastics and close to that of fuel or even higher (for polyethylenes and polypropylenes).

To do this, these materials should be treated in a manner identical to that used for other fuels: coal, fuel oil and gas. These fuels are processed industrially purified calibrated, stored, distributed by networks provided for this purpose and burned in specific facilities.

In order to be able to distribute this fuel under semi-industrial conditions, it is essential to obtain an elaborate product with characteristics that will be located in a very narrow range. This condition makes it possible to limit the combustion incidents to a significant extent.

These requirements lead to storage and homogenization facilities that will: store homogenize control the qualities of these materials aerate.

FR-A-2715329 discloses a fragmentation machine with a view to their destruction and then their recycling, of plastic parts and in particular, but not exclusively of thermoforming roll rolls. Such a machine can also shred plastic parts such as empty containers, bottles or other. In these storage silos it is possible to dump all kinds of materials in a controlled quantity in order to obtain mixing characteristics close to the standard mixture which after the homogenization and aeration operations will be available to the users. To homogenize the mixture, a mechanical extraction silo mixer is described in FR-A-2,721,288.

It is, moreover, known that in order to obtain good combustions of rigid materials it is advisable to reduce them to the state of powder, for example the coal is pulverized before combustion in the thermal power stations.

A study is used to determine the characteristics and percentages of various materials that, by combustion, emit fumes with low toxicity. The various chemical reactions that occur during combustion can be beneficial.

The mixture consists of materials that are commonly found both in industry and in everyday use In packaging, - PE (polyethylene); PS (polystyrene); ; PP (polypropylene); PVC (polyvinyl chloride); PVC-PE, PS-PE; FART; ABS (acrylonitrile butadiene styrene); Wood; Cardboard; polyurethane; Latex; In toys: -PP. ; PS; PA; ABS; SAN In household appliances

    - <SEP> Coffee makers <SEP> PP; <SEP> Cuvette <SEP> PE; <SEP> Buckets <SEP> PE; <SEP> Hair dryer <SEP> ABS; <SEP> Vacuum cleaner <SEP> ABS <SEP> PP in the furniture: - Mattress; Armchair; Chair; Bedspring; Curtains; Blanket; Carpeting in the industry PE cover; big bag PP; Cardboard; Broken pallets; Paper; Protective film; Various sweeps; Sawdust, plastic; Wood chips, plastic; Paper; Various cardboard In the automobile: - Door panels; Bumper; Dashboards; Seat; Carpet In agriculture: - Can; Greenhouse film; Mulching film; Pruning; straws TREATMENT OF MATERIALS An ultimate micronization operation makes it possible to obtain, according to these materials, a particle size of the order of a millimeter and with many products smaller than this millimeter. This presentation allows easy handling and projection into the homes in the form of "jet" whose vector element is pressurized air. The small size of the fuel has the effect of obtaining good combustion and a very low residue with little unburnt.

Micronization, the ultimate operation of the treatment, can only be done after a rough preparation which is obtained by machines of various and specific constructions: shredders; hammer mill; knife mill; shears; guillotines; densifiers; trommel; sieve; magnetic separators; metal separators; over bands. Two or three operations are required depending on the original dimension of the products to be burned. RUSTIC MATERIALS AASPECT DUR a) Shredder or coarse hammer mill. With passage under an over band in order to remove metal parts by magnetization b) Grinding calibrated by a grid of appropriate diameter ranging from 6 mm to 20m mc) A micronisatJ`on with a particle size of the order of one millimeter depending on the materials SOFT MATERIALS AASPECT MOU a) Shearing b) Shredding c) Densification B) PACKAGING OF THESE MATERIALS All these materials are packaged in buffer silos described in order to collect in large quantities all these shreds. These for transport matters can be packaged in BIG-BAG; c) PREPARATION OF THE FUEL The preliminary mixing studies that have been done these different materials are stored and mixed in a homogenizer silo such as that subject of the aforementioned patent.

These materials will be loaded alternately in high capacity silos and homogenized during the nights from 22 hours to 6 hours for electricity costs. This homogenization operation has the advantage of aeration products and thus avoid the risk of fermentation and as a result of explosions. Each silo is, if possible, fully loaded so that the contained products are perfectly homogeneous. This quality seems very important to obtain highly effective smoke treatments. It is obvious that a heavy installation as defined above requires users with large energy potential such as: factory; high school; school; barracks; Z.U.P .; middle School; hotel; supermarket etc ....

It goes without saying that many variants can be made, in particular by substitution of equivalent technical means, without departing from the scope of the invention.

Claims (1)

<1> A process for treating mixed plastics, characterized in that it consists in spraying them, homogenizing the mixture and then burning them. 2 Process according to claim 1, characterized in that the materials are crushed and micronized, then introduced into homogenization silos and burned in the form of "jet" whose vector element is pressurized air. 3 treatment process according to claim 1, characterized in that the ultimate micronization operation reduces the materials to a particle size at most equal to one millimeter.