SE511292C2 - Method and apparatus for producing fuel body - Google Patents

Abstract

The present invention concerns a method and a device for manufacturing composite fuel bodies such as briquettes and similar that include one or more solid combustible materials. The method for manufacturing solid, composite fuel bodies from one or more ground-down combustible components includes the ground-down combustible components, that partly comprise ground-down reed canary grass, being compressed to fuel bodies, whereby thermoplastic in molten form is added to the solid component forms prior to compression. The device for manufacturing fuel bodies includes a mixing zone for mixing the ground-down combustible materials that comprise the fuel body, a compression zone for compressing together the components into a fuel body, and an inlet arranged at the mixing zone for supplying the ground-down combustible material in solid form, in which a nozzle is arranged through which the thermoplastic is fed out in molten form.

Description

10 511 292 2 The sewing is achieved with a method and a device as first mentioned above and which exhibits the characteristics defined in the characterizing part of the appended independent patent claims.

Embodiments of the invention will be apparent from the following dependent claims patent claims.

It is desirable that the materials which form the briquette themselves effect the bonding, without additive binder. We therefore use the energy content enhancing component thermoplastic as a binder.

In order for the volume of thermoplastic used in the briquette to be minimized and for that its potential as a binder to be utilized it melts when compressed by the briquette.

The temperatures required to melt thermoplastics, such as e.g. polyethylene or polypropylene, to an extent sufficient for it to act as a binder, is usually in the range 200-230 ° C. To heat the compression device to those temperatures however, is not entirely hassle-free. The thermoplastic tends to stick to the compression means, at the piston or screw conveyor. Another problem that arises is that wood components starts caramel and risks catching fire. The charring process begins already at temperatures around 120 ° C and then increases with increasing temperature.

Our invention also solves these additional problems.

Additional features and advantages will be apparent from the following description of a non limiting but preferred embodiment of the invention.

In the following description, references are made to the accompanying drawing, in which fi g. 1 schematically and partially broken away shows a perspective view of a device according to a embodiment of the present invention.

Ifig. 1 shows a device for continuous production of fuel bodies in the form of briquettes from solid combustible solid material, according to a preferred embodiment of the invention.

Device comprises a mixing zone for mixing components contained in the fuel body components, a compression zone for interconnecting compression of the components and an output zone for output from the compression zone of the one formed there the fuel body. Furthermore, an inlet is provided to the mixing zone for supply of the decomposed combustible material in solid form and that in the inlet a nozzle is arranged for discharge of thermoplastic in surface form. cAusemmxaoxxmsavzsßooßfneueraæ Alnnununer: P33471SE00 / TK Veßion 1997-1016 511292 The device comprises in more detail at least one feed device e.g. in shape a conveyor belt 1 for feeding the solid form components to the feed zone 2.

The conveyor can be of any kind obligatory for feeding solid materials in decomposed before, e.g. conveyor belt, chute, closing plane, or a dispenser at the bottom of a container. In the example shown, the conveyor is a skmv conveyor 1. The conveyor feeds the solid form components in an adjustable amount per unit time. Wanted carefully regulation of the composition of a number of components in solid form can advantageously be one adjustable conveyor is arranged for removal of the respective component.

The conveyor 1 feeds the disintegrated solid material to the feed zone.

The feed zone comprises the inlet 2 to a mixing zone 3. In the mixing zone it is mixed added solid material.

In the present embodiment, the mixing zone is substantially cylindrical chamber 4. A mixing screw 5 is arranged in the chamber for agitation and axial for fl transferring the solid mold components supplied to one end of the chamber through the inlet.

To improve the agitation and mixing can be along the interior of the chamber 4 walls be arranged projections not shown, the purpose of which is to prevent the screw from slipping transported material only slides along the walls of the chamber without mixing. Parts of the fastening components, those which are closest to the wall 4 of the chamber, are removed the mixing screw against the projections and is forced there to a stop, forming agitation.

The projections can be made as a ridge arranged in a continuous helical shape from the karnmarens one to the other end of the chamber, as annular ridges around the chamber, as discontinuous stirring protrusions distributed outside the chamber, etc. A prerequisite, however, is that the protrusions radial extent in the chamber does not obstruct the screw 5. An example of a suitable radial extent in the chamber 4 of the projections is 5 - 10 mm. An example of a suitable game between projections and the radially outer parts of the screw, are 3 - 10 mm.

The mixing screw 5 is preferably connected to a suitably adjustable drive means, such as e.g. an electric motor with water control.

At the other end of the karnmar 4 the compression zone connects. Compression zones can be said to comprise the end of the chamber 4 and a diameter restricting extension thereof.

The diameter restricting extension in the present embodiment comprises one compression nozzle 6. The compression nozzle has a narrower opening 7 converging channel 8. The converging channel may be circular or have another cross-sectional shape It can also have varying cross-sectional shapes at different positions. The opening 7 affects the shape of the briquette discharged thereby, and may be circular, oval, Akmumnrer: P33472SEOO / TK Version [997-1016 C: \ users \ tk \ dok \ P3347ßEO0Brikenerdoc 511 292 4 rectangular or given another suitable or desired shape. In the example shown, it is converging channel circular with an even dimensional change.

Outside the opening 7 is arranged a forming nozzle 9, the inside of which channel cross-sectional shape closely connects to the cross-sectional front of the opening 7, but which then diverges to meet the tendency of the discharged compressed briquette to expand slightly.

Furthermore, a nozzle 10 is arranged in the feed zone, extending into the inlet 2, for discharging thermoplastic in molten form. This output preferably takes place through a spreading nozzle, to effect distribution of the molten plastic among the solid components even before they enter the mixing zone 3.

The supply of the molten thermoplastic is preferably continuous and from one suitable device, e.g. an extruder, s.k. extruder.

The extruder can advantageously be loaded with crushed, ground or granulated recycled thermoplastic. The extruder may be from someone on the market standard type or be a specially made one constituting an integral part with the others the parts of the device.

The heating nozzle 9 can advantageously be provided with heating means, in condition to keep the nozzle at a temperature of about 80 ° C or within a range of 80 ° C, i5 ° C.

The process for producing composite fuel bodies in a continuous process according to the present embodiment comprises that disassembled solid state components, such as ground, chopped or komponenter iced components, of combustible material, thermoplastic is added to molten form, preferably by means of a spreading nozzle, before the components are compressed to a fuel body. Preferably, the molten plastic is added before mixing the solid fuel components take place. The solid fuel components are supplied in a feed zone with determined flow. Thermoplastic is supplied to the feed zone by means of a spreader in connection with the entry into the mixing zone in molten form and with a fixed fl fate.

Experiments have shown that a briquetted mixture of 70% combustible wood material and 30% recycled plastic, in a fraction representative of plastic recycling today, meets the environmental requirements well when burned in a medium-sized boiler. This generally refers to the percentage by weight when mixtures are discussed.

Normal recycled plastic fractions are considered to contain LDPE, HDPE, ABS, PVC, EPDM, polystyrene, polypropylene and polycarbonate.

In normal recycled plastic fraction, the proportion of PVC-containing plastic is usually less than 10% the fraction. In order to meet the environmental requirements, this should therefore be taken into account when preparing recipes, the total chlorine content of the briquette should be less than 1%.

Annumrner; P334725E00 / TK Version 1997-1016 C: \ users \ tk \ dok \ P334Tßlšwßriketter.doc 511292 ___A addition of the pipe flange to the wood material has been shown to have positive environmental effects the combustion. The tube helps to bind e.g. chlorine, which is known to be found in PVC. The pipe can advantageously included in the briquette with a weight fraction of 0-10%, preferably 10%. A higher proportion have could not be shown to further increase the positive environmental effects.

The term molten plastic has been used above. This does not mean the solid phase of the material but its surface phase, regardless of viscosity.

From an environmental point of view, the proportion of plastic included in the briquette should not exceed 30%.

In a larger proportion of the total plastic supplied to the briquette which is supplied in molten form, the more compact the briquette becomes and thus its energy content increases further in proportion to if part of the plastic has been added in solid form.

Aklnummcr: P33473E0O / TK Version 1997-10-16 C: \ use | s \ tk \ d0k \ P33472SE00> Brik: ner.doc

Claims (10)

10 15 20 25 30 511 292 6 Patent claims A method of making fuel bodies of one or more decomposed combustible components in solid form comprises compressing the decomposed solid components into fuel bodies, characterized in that the solid components consist of a part of the disintegrated tubular component and the thermoplastic component. 2. A method according to claim 1, characterized in that the solids components are supplied with a certain flow, that molten thermoplastic is supplied with a certain fate, that after mixing the solids components and the thermoplastics are passed through a compression zone, for compaction to fuel bodies. Process according to one of Claims 1 to 3, characterized in that the proportion of tinplate supplied in molten form is in the range from 10 to 30% by weight, preferably from 30% by weight. 4. A method according to claim 3, characterized in that the proportion of plastic material added to the briquette in total is less than 30% by weight and that the proportion of plastic material supplied in solid feed is less than 10% by weight. Method according to one of the preceding claims. know that the proportion of pipes fl one amounts to 1-10% by weight, preferably 10% by weight. An apparatus for producing fuel bodies in a continuous process by the method of claim 1, comprising a mixing zone for mixing components of the fuel body of decomposed combustible material, a compression zone for bonding compression of the components into a fuel body, characterized in that a inlet is arranged to the mixing zone for supply of components in solid form and that in the inlet a nozzle is arranged for discharging thermoplastic in molten form. Device according to claim 6, characterized in that the nozzle has a number of openings for spreading the thermoplastic discharged into the molten mold. Device according to one of Claims 6 or 7, characterized in that the mixing zone comprises an internally substantially cylindrical housing, in that an axially acting feed knife is arranged in the housing for mixing and feeding material, in that said inlet is arranged at one end of the housing and at the other end of the housing is provided with said compression zone. 9. A device according to claim 8, characterized in that the compression zone connects to and constitutes an extension of the housing, that the compression zone has a converging cross section producing said compression of the fed material. 7 511 292 Device according to one of the preceding claims, characterized in that a discharge nozzle is provided as a direct extension of the compression zone, with a channel diverging relative to the opening of the compression zone for receiving the briquette formed and that the discharge nozzle has a temperature in the range 60-90 ° C, preferably about 80 ° C.