DE102004005058A1 - Firelighter material manufacture involves mixing ground wood with a plastic matrix, foaming and cutting into suitable lengths - Google Patents

Abstract

Wood is ground into particles which are added to a plastic matrix. The plastic is then foamed to create a material suitable for firelighter manufacture. The plastic is fluidized at elevated temperature and high pressure to enable the wood particles to be incorporated. Compounds are produced in an extruder(1) in which the plastic is fluidized at high pressure and temperature to allow combining with the wood particles. Wood particles are initially dried in a fluidized layer, stored in a drying vessel and fed in a dry line to the extruder. Additional drying of particles is achieved by degassing the wood and plastic melt mixture before mixing in a blowing agent. Molten extruded compound is cooled(3,4) and cut into short lengths. The wood and plastic compound(5) has a density of not >0.4kg/cu dm, preferably not >0.2kg/cu dm and/or a plastic content of not >59vol%, preferably not >40vol% and more preferably not >30vol%.

Description

The The invention relates to the production of Feueranzündmasse. Feueranzündmassen should burn easily. senseless People always use gasoline or the like as Feueranzündmassen. Leading then to jet flames, which are not only dangerous, but also the Feueranzündmasse partly let us waste useless.

The The invention therefore has the task of a Feueranzündmasse to create, which burns slightly, but in no way prone to stinging flames.

To the invention is achieved with the features of the claims. The invention is based on the development of a fuel, which consists of a mixture of wood and plastic. From the mixture is lumpy Firewood, in particular firewood logs have been molded. That was the realization that is the flying sparks reduced with increasing crushing of the wood and that one Drying the crushed wood is more economical than one Drying of the uncut wood, because the drying under the same Environmental conditions much faster with shredded wood takes place as unzerkleinertem wood. It falls the crushing effort across from the advantages of faster drying hardly significant. By namely, slow drying will be for long Time storage space and weather protection required. In addition, will Capital tied up.

It has been shown that a extremely short drying in a drying device pays off.

The Crushing and drying leads but not yet to a suitable firewood. Rather shows yourself, that one bulk location from finely chopped wood does not burn easily. It's for improvement Burning known to produce wood pellets.

nevertheless However, open fires are operated with firewood. Traditionally is interested in the selection of special types of wood and their special drying recorded.

The explained Development triggers away from it and replace the familiar lumpy firewood for open ones Firings, especially the firewood by wood after the Features of the claims.

there a significant better combustion is achieved in that the fine Wood particles are joined together by plastic. Especially lends itself to the use of waste plastics.

To the explained Development, the wood particles are connected to lumpy firewood.

For the mix Made of plastic and wood are a variety of plastics Available, whose Burning completely is harmless. This is true for example for polyethylene because of the Combustion of polyethylene only water and carbon dioxide is obtained. For the use according to the invention Polyethylene is also suitable for recycled polyethylene. advantageously, No purity is required, otherwise recycling of plastics makes expensive.

To the older one Development, the plastic forms a matrix into which the wood particles be embedded. The process is carried out with considerable pressure.

Surprisingly the necessary amount of plastic for the matrix is relatively low. Sufficient already 10 vol% to 20 vol% plastic, based on the amount made of wood and plastic. at the most the proportion of plastic should be 50% by volume, preferably at most 40% and even more preferably at most 30% by volume.

To the older one Development creates a fuel with a density of at least 0.9 kg / cubic decimeter, which gives a slow and safe burnup shows. That does not indicate the possibility to use as ignition composition out. Nevertheless, the invention builds on it. After the invention becomes the aptitude for Anzündmassen achieved in that the Foamed plastic matrix becomes. The foamed Plastic accelerates the burnup to the necessary level, in which the further fuel is ignited. Advantageously, the combustion time is for so long, that too damp and / or cold coal or wood is set on fire.

Preferably caused by the foaming the plastic room weights below 0.4 kg per cubic decimeter, still more preferably below 0.2 kg per cubic decimeter, based on the wood-plastic mixture. It can Space weights between 0.05 and 0.15 kg per cubic decimeter arise.

Otherwise it is It is beneficial to incorporate waxes in the mixture. It can it is natural Waxes or plastic waxes act. Particularly suitable are polyethylene waxes.

For the foaming of the invention Plastic is the preparation of the mixture in an extruder advantageous because the mixing process can be used at the same time for mixing or homogenizing and dispersing propellant.

Because of the details of the feedstock, especially the wood particles and suitable plastics and extruding a wood-plastic mixture is directed to EP0201527A, US5997784A, US5985429A, US6003277A, US5932334A, EP0028775A, US5518677A, DE19737647 and Saechtling, plastic paperback, 27th edition, incorporated by reference.

Further Significant advantages arise when using an extruder for the Mix of wood and plastic or for the incorporation of wood in the plastic as well the incorporation of the blowing agent

advantageously, allows the extruder by degassing the wood-plastic melt in a simple way, a further drying of the wood particles. The degassing takes place before the addition of propellant.

Cheap is Also, the wood-plastic melt mixture under considerable pressure to process. This intensifies networking even further.

Of the Pressure can also be used to melt plastic, if the plastic is not molten but in granular form or other particle forms firmly entered with the wood in the extruder becomes. The same effect has the heating of the plastic.

The Propellant may be a chemical propellant, which with the other feedstock is fed into the extruder.

Contemporary propellant However, they are physical blowing agents after melting of the plastic pressed into the extruder and there in the Mixture be incorporated. Carbon dioxide is an inert blowing agent, which, however, does not hinder combustion, because it is like other usual Propellant diffused out of the resulting and cooled plastic foam. Instead of the propellant air enters. The process takes depending on Gas varies in length.

Under the existing pressure in the extruder, the blowing agent remains in mixture with the plastic. The pressure drops However, drastically decreases when the mixture leaves the extruder, so that, for example, liquid carbon dioxide turns into gas in the melt and the gas expands. Thereby arise in the plastic cells that characterizing the foam are. Instead of carbon dioxide, there are several others Blowing agent into consideration. Because of the different propellants and their handling is on Saechtling, plastic paperback, 27th edition, 5,271,532 and 768.

In order to it does not block the extruder due to the wood particles comes, is preferably a minimum distance between the extruder parts provided that is greater than the usual Distance is the result of the necessary clearance between moving extruder parts or between fixed and moving extruder parts. After Invention is the minimum distance to the dimensions of the wood particles customized, So that the Wood particles between the teeth of the extruder, without blocking the extruder. Distinguish the affected extruder parts depending on the extruder type. There are single screw extruders, twin screw extruders and Planetary roller extruder. Usually Each extruder consists of sections. For example, there is the Intake area, the melting area, the dispersion area, the homogenization area and the cooling area. The types can also switch from area to area.

At the Single-screw extruder is a screw provided in one cylindrical housing rotates.

The Snail usually exists from a centrically arranged pole. One is sitting on the pole Variety interchangeable snail parts, with the help of the rod be braced against each other. By replacing the items can the correct distance of the screw from the surrounding housing wall Optimize extensively with a few experiments.

At the Twin screw extruders are two rotating screws in one common housing arranged so close together that their teeth mesh with each other to grab. The individual screws of the twin-screw extruder are just like the screw of the single screw extruder. By similar Replacement process can also be made here an optimization.

In the planetary roller extruder a circumferential central spindle is provided. On the central spindle planetary spindles run around. The planetary spindles engage with their teeth at the same time in the teeth of the central spindle and in the teeth of an internal toothing of the surrounding housing. The central spindle is usually constructed in the same way as the screws or twin screws. The planetary spindles, however, are always in one piece, as is the internal toothing always in one piece. To optimize the planetary spindles and the parts change the central spindle.

In the drawing is an embodiment of Invention shown.

1 shows an extruder plant 1 with a hopper 1 , In it, wood particles from a previous wood shredding and drying are filled. In the exemplary embodiment, a particle size of less than 1 mm is achieved by comminution. The drying takes place in a fluidized-bed plant which is operated with an inert heated gas. In the inert gas stream, the wood particles are carried and heated. As a result, the moisture is expelled from the wood particles. It is advantageous to then store the wood particles in a drying room until the wood particles are used in the extruder.

The wood particles are put into the extruder together with PE granules 1 guided. There, the feed mixture undergoes strong compression and heating. The PE granulate melts and wets the wood particles intensively.

To the melting of the plastic is carbon dioxide in the embodiment in liquid form pumped into the extruder. The carbon dioxide is passed through the extruder mixed into the plastic melt.

The extruder has a nozzle on the outlet side. The nozzle forms a strand from the wood-plastic melt 5 , The strand 5 foams up after leaving the nozzle. The strand enters into a cooler with metal plates 3 and 4 and other metal plates, not shown. The metal plates give the strand by cooling a desired shape and sufficient strength to be performed on a roller table. The roller table consists of rollers 6 that with a mechanics 7 are height adjustable.

To sufficient further cooling for one cutting to length the strand is made to a desired degree the cut to length with a saw, the while the cutting process in a manner not shown with the strand moved back to the starting position after the cutting process.

Claims (9)

Process for the preparation of igniter compositions Wood, characterized in that Wood is crushed and the wood particles into a plastic matrix foamed becomes. Method according to claim 1, characterized in that that the Plastic is liquefied to embed the wood particles, in particular under Pressure and temperature. Method according to claim 2, characterized in that that one Wood-plastic mixture is produced with a density of matter, the maximum of 0.4 kg per cubic decimeter, preferably at least 0.2 kg per cubic decimeter is and / or a plastic content of at most 59% by volume, preferably at the most 40% by volume and even more preferably at most 30% by volume. A method according to claim 1 or 2, characterized through the use of polyethylene as a plastic. A method according to any one of claims 1 to 4, characterized by the interference of a chemical or physical Propellant, especially of carbon dioxide in the molten Plastic. Method according to one of claims 1 to 4, characterized by preparing the mixture in an extruder. Method according to claim 5, characterized in that that the Wood particles dried in a fluidized bed and stored in a drying container and be fed in a dry line to the extruder. Method according to claim 5 or 6, characterized that the Wood particles are dried by degassing the plastic-wood melt, wherein the degassing takes place before the addition of propellant. Method according to one of claims 5 to 7, characterized that the Melt is driven out of the extruder in a cooler and the resulting strand then cut to length becomes.