Method for the pyrolysis of raw materials, in particular raw materials deriving from tires or bitumen and pyrolysis equipment operating according to said method

Abstract

A method for the pyrolysis of raw materials, especially raw materials deriving from tires or bitumen, includes the steps of feeding the material to be subjected to the pyrolysis process to a reactor; heating the material in the reactor at a temperature needed to establish the pyrolysis process; collecting the final products of the pyrolysis reaction; separating the gaseous, liquid and solid phases of the reaction products; and storing, for further treatment, the reaction products separate one from another. The heating in the pyrolysis process to the activation temperature is obtained by irradiating the raw material with laser radiation, concentrated or focused on a localized area of a pre-established surface area on the mass of raw material of the focusing area, and progressively moved along the entire surface of the mass of raw material to activate the pyrolytic reaction on all the mass of raw material.

Claims

1. A method of pyrolysis of raw materials, comprising the steps of: feeding, to a reactor, a material to be subjected to a pyrolysis process; heating said material in said reactor at an activation temperatures needed for establishing a pyrolysis process reaction; collecting final products of the pyrolysis reaction; and separating one from another gaseous, liquid and solid phases of reaction products and storing, for further treatment, said reaction products separated one from another, wherein: heating to the activation temperature comprise irradiating the material with laser radiation, and said laser radiation is concentrated or focused on a localized area of a pre-established surface area of a mass of the material, said laser radiation being progressively moved along an entire surface of the mass of the material by activating the pyrolysis reaction on all of said mass of the material.

2. The method according to claim 1, wherein the activation temperature is such to transform the mass of the material into a mixture of ablation gas containing the reaction products intended to assume a gas and/or liquid phase condition, which are drawn by suctioning the reaction products intended to assume a gas and/or liquid phase condition from a reaction station in a drawing room open towards the reaction station and set at a pressure lower than a pressure of the reaction station.

3. The method according to claim 1, wherein separating the reaction products having the gaseous, liquid and solid phases comprises condensing the mixture of ablation gas with a cooling step of said mixture of ablation gas at a pre-established temperature.

4. The method according to claim 2 wherein the activation temperature is from 420° C. to 950° C., further comprising a pre-heating step of the material, wherein a pre-heating temperature is from 45° C. to 200° C.

5. The method according to claim 2, further comprising feeding an auxiliary gas into the drawing room, into a flow of reaction gas mixture.

6. The method according to claim 1 wherein the laser radiation has power of at least two hundred Watt/cm.sup.2, and transfers on a piece to be pyrolyzed at least 100 W/cm.sup.2, with wavelengths of the laser radiation that can range, in diode and solid state lasers, from 600 to 1100 nm, or a frequency of 10000 nm, for CO.sub.2 gas lasers.

7. The method according to claim 1, wherein the mass of the material to be treated by the pyrolysis process is constituted by tires of vehicles and/or bitumen and materials containing bitumen and waste or scraps having a composition allows the pyrolysis reaction to be activated by using the laser radiation.

8. The method according to claim 1, further comprising a step of maintaining a temperature of the reaction products constant at a value of the reaction temperature, from ablation time until the reaction products having different phases are separated.

9. The method according to claim 1, further comprising a step of taking real time measurements on the reaction products during the reaction, and generating immediate feedback adjusting irradiation energy by using the laser radiation or a laser radiation from another source to determine a concentration of the reaction products in gas generated by the pyrolysis reaction.

10. A method of Method for producing Syngas, TAR liquid reaction products and CHAR solid reaction products, the method comprising: feeding, to a reactor, a material to be subjected to a pyrolysis process; heating said material in said reactor at an activation temperatures needed for establishing a pyrolysis reaction; collecting final products of the pyrolysis reaction; and separating one from another gaseous, liquid and solid phases of reaction products and storing, for further treatment, the reaction products separated one from another, wherein: heating to the activation temperature comprises irradiating the material with laser radiation, and said laser radiation is concentrated or focused on a localized area of a pre-established surface area of a mass of the material, said laser radiation being progressively moved along an entire surface of the mass of the material by activating the reaction on all of said mass of the material.

11. Equipment for pyrolyzing raw materials, comprising:: a reaction station; a feeding area having feeders of a mass of raw material; a source transmitting thermal energy to the mass of raw material fed to the reaction station in order to induce a pyrolysis reaction in the mass of raw material and produce reaction products having different phases; a drawing member to draw the reaction products from said reaction station; and a separator having a separation chamber of the reaction products having the different phases; wherein: the reaction station is provided between the feeding area of the raw material and the separation chamber of the reaction products and is functionally separated from said feeding area and said separation chamber, and the source transmitting thermal energy to the mass of raw material comprises a laser source producing laser radiation for generating a distribution of electromagnetic energy on an irradiation surface of a pre-established size and smaller than the surface exposed to said radiation of the mass of raw material.

12. The equipment according to claim 11, wherein one or both of the laser source or the raw material are supported by handling structures which generate a relative movement between the mass of raw material and an incidence area of the laser radiation, causing a movement of said incidence area along a surface exposed to the laser radiation of said mass of raw material.

13. The equipment according to claim 11, further comprising a condenser in which a separation of the reaction products according to the different phases thereof is performed at room or storage temperature conditions at a temperature lower than a reaction temperature, the condenser cooling a gas fed by the drawing member at liquefaction or solidification temperature of the reaction products, whereby at the storage temperature conditions the reaction products in gaseous, solid and liquid phases are separated and are ready to be stored separately.

14. The equipment according to claim 11, further comprising a feed branch of an auxiliary gas at the drawing member, downstream of a suction orifice of the reaction products in a gasified form from the reaction station.

15. The equipment according to claim 11, further comprising a controlling system of a type and concentration of the reaction products, the controlling system having detectors of presence of said reaction products and measurement sensors of the concentration of said reaction products.

16. The equipment according to claim 11, further comprising a laser source or an array of laser sources, selected from the group consisting of a diode laser, a solid state laser, and a CO.sub.2 laser.

17. The equipment according to claim 11, further comprising a focusing/distributing system that focuses/distributes a beam of the laser radiation.

Description

[0095] The characteristics described above and other characteristics, with the related advantages of the present invention, will be clearer from the following description of some exemplary embodiments depicted in the attached drawings wherein:

[0096] FIG. 1 shows a schematic view of an exemplary embodiment of a piece of equipment for the treatment of raw material, in particular raw material such as waste and especially raw material constituted by vehicle tires.

[0097] FIG. 2 shows a flow diagram of a treatment process of raw material implemented with the equipment of FIG. 1.

[0098] FIG. 3 shows a table summarizing the composition of the molecules constituting the Syngas (CH.sub.4, H.sub.2, CO, CO.sub.2, etc.) obtained from the pyrolysis of vehicle tires and having a Lower Heating Value (LHV) and moisture as a function of the reaction temperature.

[0099] FIG. 4 shows the composition of the Syngas in terms of elements, ashes and moisture as a function of the type of tire used: Car, Truck or OTR.

[0100] FIGS. 5 and 6 show the composition of the reaction products in the liquid phase (TAR) and in the solid phase (CHAR).

[0101] With reference to FIG. 1, the latter shows a schematic example based on which the possible variations will be depicted and will be clear to the technician of the art, if referred as differences or variations of the example depicted.

[0102] The depicted example is referring to a specific application wherein the raw material to be subjected to the pyrolysis reaction is constituted by vehicle tires or similar materials.

[0103] The raw material to be subjected to the pyrolysis reaction is denoted with 1 and is transported by a conveyor 2 to a reaction station 3, wherein an area at high temperature is generated by the irradiation of the raw material with the laser radiation 104 generated by a laser source 4 or a combination of more than one laser source 4.

[0104] The radiation 104 is distributed on the raw material 1 so as to generate an incidence area of said radiation 104, also called footprint, wherein the radiation 104 is distributed so as to heat the raw material coincident with said footprint 204 to the expected reaction temperature. At this reaction temperature the pyrolysis reaction is activated and part of the material the raw material is constituted by, is gasified as depicted by 5.

[0105] In some configurations and for some laser types, a lens 304 or a device forming the radiation beam 104 can be provided and is depicted by 304.

[0106] The reaction products in the gaseous form 5 are separated from other materials remaining on the conveyor 2 which are brought, as the raw material is moved forward in the reaction station, to an unloading station and drawn for a further treatment, not specified because it is not an object of the present invention.

[0107] The gasified reaction products 5 are drawn in different ways. A preferred embodiment provides for the gas being suctioned thanks to a drawing tube 6, whose open end is provided as coincident with the reaction station and wherein depressurization is generated with respect to the external environment and/or the reaction station.

[0108] Thus the reaction products under the gaseous form are transferred from the feeding duct to a separation chamber 7, wherein the reaction products having different phases such as the gaseous phase, so-called Syngas, the liquid phase so-called TAR essentially constituted by oils and the solid phase so-called CHAR, are separated one from another.

[0109] The separation among products having different phases is carried out thanks to a condensation process obtained by cooling the reaction products still at the reaction temperature to a lower temperature, in particular to room temperature or a typical storage or usage temperature of these products.

[0110] Thus the phase separation allows the separated collection and separated storage of each reaction product having gaseous, liquid and solid phases, as depicted by the tanks or warehouses 8, 9, and 10.

[0111] In order to avoid the cooling of the gas produced in the reaction station and thus a separation of the various phases already along the path of the drawing tube 6 and feeding ducts towards the separation chamber 7, along said path passive and/or active devices could be provided for preserving the temperature of the gas produced in the reaction station.

[0112] Such passive devices can be constituted by a thermal insulation of the drawing tube 6 and feeding ducts 107 to the separation chamber 7. The active devices can be sources feeding thermal energy and configured so as to bring a contribution of thermal energy substantially corresponding to the dissipated heat and thus to compensate the heat losses of the gas passing through the drawing tube 6 towards the separation chamber 7.

[0113] Obviously the two types of devices can be present in combination. The specific selection of insulations and/or sources of thermal energy to maintain the gas temperature can fall on any known type and depends on the specific structure of the equipment, the heat losses to be compensated and other considerations of opportunities dictated by the conditions of the specific application. Such alternatives are part of the base knowledge of the technician of the art and their selection falls within the normal activities of equipment design.

[0114] According to a further characteristic, a feed branch 206 of an auxiliary gas opens into the drawing tube 6 from a tank 306 of said gas. This gas can alternatively or in combination have different functions.

[0115] A first function is to enrich the Syngas so as to optimize the composition for its subsequent exploitation.

[0116] A second function is to protect the lenses 304 of the laser sources 4. In this case the auxiliary gas is constituted by, or comprises, an inert component.

[0117] A possible embodiment variation provides for insulating the reaction station from the environment, so that the reaction occurs in the absence of oxygen.

[0118] Also in this case, the technician of the art is able to configure a chamber enclosing the reaction station and allowing the raw material to be fed and the residual material of the pyrolysis reaction to be unloaded, so as to avoid ambient air and thus oxygen to pass in said chamber, since in the state of the art there are a number of solutions among which the technician of the art can choose depending on the raw material which is treated and other specificities of the different cases of use.

[0119] The depicted example shows a design wherein the drawing tube 6 opens into the reaction station and the laser radiation 104 is transmitted through said drawing tube 6 substantially coaxially or parallel to the axis of the same.

[0120] Such a solution allows also the radiation to be used as a source to maintain stable the temperature of the gas containing the reaction products during the path in the drawing tube 6.

[0121] Different alternatives are possible, one of which provides the laser source 4, both in the form of unique source and in the form of a combination of laser sources such as an array of laser diodes, being provided outside the drawing tube 6 and the radiation being transmitted to the footprint 204 on the raw material 1 passing through the reaction station from the outside of said tube.

[0122] In this case the optical axis of the radiation can be parallel to the axis of the drawing tube 6 or else it can be inclined with respect to the axis of the tube.

[0123] When a delimitation of the reaction station is provided in a reaction chamber, the source 4 or the combination of sources 4 can be provided outside or inside said reaction chamber.

[0124] Still according to an embodiment variation, instead of providing a conveyor 2 of the raw material to be pyrolyzed and instead of keeping stationary the footprint 204 generated by the laser radiation 104, it is possible to provide for moving said footprint 204 only, for example by translating the laser sources so as to move the footprint 204 on the surface of the mass of raw material 1, or else it is also possible to provide a combination of reciprocal movements of the raw material 1 and the footprint 2. Such a solution could for example provide a translation of the raw material 1 through the reaction station along a first direction, as depicted by the arrow D in FIG. 1, whereas the footprint is moved along the surface of the mass of raw material 1 in a direction perpendicular to the feed direction of the material 1 depicted by the arrow D. In this case, it could be a flow of raw material having width size, that is perpendicular to the feed direction, greater than the extent of the footprint 204 along said direction perpendicular to the feed direction of the mass of raw material 1.

[0125] The raw material 1 can be subjected to preventive mechanical machining reducing its dimensions and shape, such as for example the segmentation into parts and/or the separation of parts constituted by different materials, or else the shredding to pre-established granulometry.

[0126] Depending on the physical conditions of the raw material, it is possible to use different types of conveyors, such as linear belts, rotary augers, or the like. Such conveyors are known in the state of the art and the specific choice is a choice which is part of the design activities of the technician of the art and is based on the contingent conditions of the raw material.

[0127] For what concerns the drawing tube, this can be made as in FIG. 1, or else it can be in the form of helical tube wrapping itself around the beam of laser radiation 104. In this case more than one coaxial helical tube can also be provided. Also in this case, despite the laser radiation 104 is outside the drawing tube, it can interfere with the same at least in the peripheral area of the beam and can transfer thermal energy to the drawing tube to an extent sufficient to compensate for the heat losses and thus the temperature losses of the drawn gas.

[0128] In combination with an embodiment wherein the footprint 204 of the laser radiation on the surface of the material 1 is translated along said surface, it is also possible to provide for the moving of the drawing tube 6 along a path corresponding to that of said footprint 204.

[0129] For what concerns the type of lasers used, these can be selected depending on the raw material to be treated and the desired reaction temperatures in combination with the qualitative composition of the raw material.

[0130] When, as in the present application, you want to treat a raw material constituted by vehicle tires, it is substantially possible to provide three types of laser sources, which choice derives from the specific characteristics of this type of raw material.

[0131] A first relevant characteristic for the choice of the laser sources concerns the wavelength of the radiation, which is related to the generated thermal energy and the absorption effect of such energy by the raw material and thus the efficiency of the heating action of the raw material at the desired reaction temperature.

[0132] A first aspect of the specific raw material is that the material of which the vehicle tires are made of can be equated, to a first approximation, with a black body for what concerns the absorption and dissipation behaviors. In fact this material absorbs well the radiation of any wavelength and the heat dissipation by irradiation is low.

[0133] By analyzing the absorption spectra of the main components of a tire, it is possible to verify that the interest frequency range is from 400 nm (blue) to 2300 nm (medium infrared).

[0134] Based on these considerations, an embodiment provides for the possible wavelength being in the range between 600 nm and 1100 nm.

[0135] Among the existing laser sources, there are diode lasers and solid state lasers.

[0136] Such sources, if taken with power of at least 1 KW, are able to generate the power needed to heat the raw material to the expected reaction temperatures. This power is then translated on the material with a minimum of 100 W/cm.sup.2.

[0137] A further embodiment is that with a wavelength around 10000 nm, covered by CO.sub.2 gas laser that can even deposit this power with sources lower than one KW/cm.sup.2.

[0138] An embodiment provides the use of a laser source or combinations of laser sources of the diode type and in particular of the type called VCSEL (Vertical Cavity Surface Emitting Laser).

[0139] With these sources it is possible to generate laser arrays that emit power even beyond 10 kW. The lasers of this type have small dimensions in the order of mm, at most some centimeter and thus the laser array doesn't get to very big dimensions negatively affecting the design of the equipment.

[0140] Despite this type of sources has a non-optimal laser beam, often a divergent one, they are extremely easy to be integrated in horizontal or vertical or customized arrays. That is so as to generate arrays having shapes ad lib, and which can be air or water cooled, or cooled by Peltier cooler systems.

[0141] A further type of lasers is that of the solid state lasers that however have a relatively high cost with respect to diode lasers.

[0142] FIG. 2 shows an example of the main steps of the treatment method of a generic raw material to be subjected to pyrolysis reaction in order to generate reaction products.

[0143] At step 200 I generates a beam of laser radiation having pre-established energy density and pre-established wavelength, for example according to one or more of the variations described above and which laser beam is adapted to generate an incidence area of the radiation on a mass of raw material, in which air the energy of the radiation is substantially distributed homogeneously.

[0144] Being laser beams, said area forms a footprint substantially corresponding to the cross-section of the beam, i.e. the projection of the beam on a plane perpendicular to the optical axis propagating the radiation.

[0145] In this case the term substantially is referred to an approximation, as the beam of the radiation of a laser source or an array of laser sources is not always perfectly parallel but can have a certain opening, even if minimal, but whose effect depends on the distance of the surface against which the beam is projected by the source or array of sources.

[0146] The beam is transmitted to the step 201 into a reaction chamber wherein, at step 202, the mass of raw material is fed. The feed takes place along a relative movement path between the mass of raw material and the footprint of the radiation projected on the surface of the mass of raw material. This path is selected and defined so as to allow the entire exposed surface of the mass of raw material to be subjected to the action of the laser radiation and thus the pyrolytic reaction to be triggered.

[0147] The described relative movement can occur according to one or more of the variations described above with reference to FIG. 1.

[0148] Possibly, as depicted by 211, before feeding the raw material to the reaction chamber, the raw material is mechanically treated, for example reduced to pieces of pre-established size or else, depending on the composition and structure, dismembered in different parts, some of which are not suitable to the pyrolysis treatment or are treated differently according to their chemical composition.

[0149] At step 203, the path and speed of the relative movement between the footprint, i.e. irradiation area and mass of raw material, are set so that all of the mass of raw material is progressively led to the reaction temperature and for the time needed to the completion of said reaction in the area hit by the laser radiation.

[0150] Step 204 provides the suction of the reaction products. Such a suction takes place according to one or more of the previously described modes and collects all the reaction products in gaseous form, whereas the reaction residues remain on the conveyor.

[0151] Step 204 can be combined with step 214, which is optional, wherein to the reaction products in gaseous form an auxiliary gas or fluid are added that can be of the type according to one or more of the previously described variations.

[0152] At step 205 the reaction products are fed to a separation chamber of said products according to the various phases they take in a pre-established environmental condition, such as for example the storage condition or the usage condition or else the external environment condition.

[0153] At step 206 in the chamber said separation of the products in the single gaseous, liquid and solid phases takes place. Such separation takes place by cooling the reaction gas and by mechanically drawing the reaction products in the gaseous, liquid and solid phases and by storing them in dedicated warehouses, as depicted at step 207 and 208.

[0154] Similarly to step 209, the reaction residues remained on the conveyor are also themselves separately drawn and stored or sent to further treatment processes.

[0155] As already described before, the invention is also referring to a particular application for which the method and the described equipment are particularly suitable. This specific application concerns the treatment of waste materials and in particular vehicle tires of any type.

[0156] As already previously described, the tires have a complex structure containing materials adapted to take part to the pyrolytic reaction and others that remain excluded. The composition of the tire depends, to a first approximation, on the use, i.e. on the type of vehicle to which is intended to and, as depicted in table 1, the main organic materials in the tires are constituted by natural rubber, i.e. caoutchouc and synthetic polymers. Furthermore, another component being in considerable amount is the carbon black or soot. These three components form more than about half of the percentage of the raw material contained in the tires. The other components and their percent amounts are depicted in table 1.

[0157] Table 2 shows the composition of the generated reaction products and related to each of the three phases (liquid, solid and gaseous) depending on three different reaction temperatures.

[0158] With reference to the above mentioned application, the method and the equipment are designed so as to generate reaction temperatures, in the mass of raw material constituted by tires, in the order of 500° C. to 700° C. and preferably in the order of not less than 600° C.

[0159] According to an advantageous characteristic, as the characteristics of the raw material are substantially corresponding to those of a black body, as already previously set forth, the choice of the electromagnetic radiation and thus of the sources and power thereof is substantially limited to laser sources able to generate at least 100 W/cm.sup.2 on the material to be pyrolyzed and with any wavelength.

[0160] A preferred frequency range essentially referring to the absorption spectrum of the main components of the tire as set forth above, provides for the wavelength of the electromagnetic radiation being in the range between 400 nm and 2300 nm, preferably between 600 and 1100 nm.

[0161] The measurements of the compositions of the reaction products for different conditions are depicted in the tables of FIGS. 3 to 6.

[0162] FIG. 3 shows the composition of the Syngas, i.e. the gaseous component of the reaction products which is obtained at the different reaction temperatures.

[0163] The Lower Heating Value of the Syngas and the moisture in the Syngas at the different reaction temperatures are also depicted.

[0164] The table of FIG. 4 shows the composition of the Syngas obtained as a function of the type of tire treated.

[0165] The tables of FIGS. 5 and 6 show the compositions of the liquid phase of the reaction products, which are substantially oils, and of the solid phase, which are substantially called TAR and CHAR.

[0166] From the tables depicted the effectiveness of the method according to the present invention and of the particular application to generate reaction products from the waste raw material having high energy value is evident.

[0167] FIG. 1

[0168] Tubo di uscita Syngas+gas ausiliario=Syngas+auxiliary gas output tube

[0169] Lente=Lens

[0170] Tubo di ingresso gas ausiliario=auxiliary gas input tube

[0171] Orma=Footprint

[0172] Pezzo di pneumatico=Piece of tire

[0173] Mezzo di trasporto del pneumatico=Tire conveying means

[0174] Zona ad alta temperature=High temperature area

[0175] Tubo=Tube

[0176] FIG. 2

[0177] 200—Generating a beam of laser radiation having a pre-established energy distribution on a pre-established incidence area

[0178] 201—Transmitting said beam into a reaction chamber

[0179] 211—In case, mechanically treating the raw material

[0180] 202—Feeding the raw material to a reaction chamber along a path crossing the beam of laser radiation

[0181] 203—Setting the relative speed of movement between mass of raw material and beam of laser radiation so that all of the mass of raw material is progressively heated to the pre-established reaction temperature

[0182] 204—Suctioning the generated reaction products being in gaseous form

[0183] 214—In case, mixing an auxiliary gas

[0184] 205—Feeding the reaction products in a gaseous form to a phase separation chamber

[0185] 206—Separating the phases of the reaction products by cooling condensation of the gas

[0186] 207—Separating the phases of the reaction products by cooling condensation of the gas

[0187] 208—Storing the reaction products, having different gaseous, liquid and solid phases, separately from one another

[0188] 209—Unloading the reaction residues constituted by the mass of treated raw material from the reaction chamber.

[0189] FIG. 3

[0190] composition of the molecules constituting the Syngas (CH.sub.4, H.sub.2, CO, CO.sub.2, etc.) and having Lower Heating Value (LHV) and moisture as a function of the reaction temperature.

[0191] FIG. 4

[0192] composition of the Syngas in terms of elements, ashes and moisture as a function of the type of tire used: Car, Truck or OTR.

[0193] FIG. 5

[0194] Liquid Oil

[0195] FIG. 6

[0196] Solid