Abstract:
The present invention relates to the recycling by depolymerisation through thermolysis. A method and installation for depolymerisation through efficient thermolysis for recycling is provided that allow the production of light hydrocarbons having high quality and being free of impurities and contaminants. This objective is achieved by methods and installations where either the secondary products of the process are re-fed to supply energy for the main recycling process or are refined to manufacture final usable and saleable products. Therefore, the use of the energy content of the starting materials is maximised by assuring their full utilisation, minimising the environmental harm while an energetically autonomous installation is provided. All the components of the waste or starting material may be recycled, by physico-chemical means, and no additional contaminant waste is produced.

Description:
TECHNICAL FIELD 
       [0001]    The present invention refers generally to the field of recycling by depolymerisation, and in particular by depolymerisation through thermolysis, where the starting materials are fully recycled, either by re-feeding part of the secondary products to supply energetically the depolymerisation or by refining part of the secondary products to obtain solid, liquid and gaseous final products suitable for consumption or sale. 
       BACKGROUND OF THE INVENTION 
       [0002]    The huge consumption of products made from materials of organic origin such as rubbers, tires, plastics and the like as well as the waste of such materials formed during manufacture processes is causing big problems with respect to storage and destruction. Besides the high costs involved, also ecologic and environmental consequences have to be considered. In the meantime, some countries have experienced such huge problems with the storage and destruction of these materials that investigation is now carried out for studying the search for and the possibility of using oceanic trenches as places of storage. The same may be said with respect to storage and destruction of oxidised oils. 
         [0003]    In the prior art, several methods for the treatment or destruction of rubbers, tires, plastics and the like are described. Such methods comprise the recycling by retreading, grinding, gasification, controlled or uncontrolled combustion (incineration), wholly treated, cryogenic systems (tyrolysis) etc. However, all these methods show some disadvantages and are not suitable for fully recycling the components present in said waste materials. Whole tires are abandoned in dumps which is not considered an appropriate solution given the high energetic value still contained in such materials. 
         [0004]    The recycled materials obtained with the above-mentioned methods may represent added value but these resulting products still are of poor quality. The grinded materials may be buried in controlled dumps or mixed with asphalt to be used later for paving. Alternatively, such materials may also be milled until granulates of different particle sizes are obtained, and may be used for incineration in cement furnaces (milled) or be a component of children&#39;s parks or sport fields (milled to micron scale). The cryogenic systems (tyrolysis) are used to separate the metal part from the rest of the organic material, which is then burned as furnace combustible. However, this direct combustion leads to contaminating effluent gases, since not all the additives have been eliminated and valuable solid compounds cannot be recovered. 
         [0005]    Pyrolysis represents a method for recycling of hydrocarbons present in the waste materials by cracking the carbon chains of the organic compounds making up said materials. The dry distillation of plastics, rubbers and tires is known in the state of the art. However, only heavy hydrocarbons in low yields are obtained and even new residues are produced which require to be treated. Sometimes, pyrolysis produces only hydrocarbons and little carbon black can be obtained. Hence, the pyrolysis of the state of the art is not very well suited for recycling waste materials and their transformation into high quality products. 
         [0006]    Moreover, pyrolysis uses typically high temperatures between 500 and 1000° C. Plants using said temperatures need a costly installation that resists to these high temperatures and it must be secured that no temperature loss occurs causing an insufficient heating. This inefficiency produces a waste of energy and the method being generally more expensive. 
         [0007]    An improvement over this kind of pyrolysis at high temperatures comprises the pre-treatment with oil to separate the metallic components in one phase. In another phase, the carbon black obtained is washed with ether to separate the inorganic impurities. However, this improvement requires more treating steps and more devices in the installation which prevent an even more direct recycling. Correspondingly, more residues are produced and, given the additional phases, the installation is more expensive. Moreover, working with a ether solvent requires very strict safety regulations due to its high inflammability, narcotic effect and potential of transforming into an explosive derivative in the presence of oxygen. 
         [0008]    Therefore, the existing systems represent low efficient recycling processes resulting in secondary residue products that contain an important stored energy value which is not reused. Moreover, some of these secondary products also are simply thrown away into the environment. None of the methods has been sufficiently efficient and convincing to not only eliminate the residue but further to obtain a use, in this case energetic, of the residues which at the moment cause big damages to us. 
       SUMMARY OF THE INVENTION 
       [0009]    The object of the present invention is to provide a depolymerisation method and installation for recycling by efficient thermolysis that allows the production of light hydrocarbons having high quality and being free from impurities and contaminants. This object is achieved by methods and installations where the secondary products of the process either are re-fed to supply energy for the main recycling process or refined to produce final usable and saleable products. Hence, the use of the energy content of the starting materials is maximised assuring their complete utilisation, minimising the environmental harm while an energetically autonomous installation is provided. 
         [0010]    The herein disclosed invention allows advantageously the transformation of voluminous residues into final products of high energy value and with a better yield, typically a yield higher than 95% of the total. Contrary to the pyrolysis of the state of the art, the herein disclosed thermolysis allows to obtain perfectly consumable products in important amounts having a strong added value with the corresponding economic repercussion for crude importing countries. The hydrocarbons obtained with the thermolysis herein disclosed have superior properties than the products of the same characteristics obtained with the best light-petroleum because according to their density, they are practically equal but during their transformation, additionally to other products, fuel oil is obtained, which is not produced in our invention, so that the yield of diesel oil is higher. 
         [0011]    Therefore, by means of the depolymerisation of the present invention the waste materials are recycled by thermolysis and purification of the solid, liquid and gaseous secondary products. All of the components of the waste or starting material can be recycled by physico-chemical means and no additional contaminant waste is produced. The preferred starting materials are tires, plastics, rubbers or multi component waste materials such as cables. Other starting materials may be oils, such as for example heavy oils, fuel oil or oxidised oil, or other organic biological material. The organic mass of the components of the starting materials is transformed into products like gaseous hydrocarbons, liquid hydrocarbons and asphaltic bitumen. Preferably, the products are selected from the group comprising metal, gaseous hydrocarbons, liquid hydrocarbons, solid hydrocarbons (waxes or tar), inorganics and carbon black (from carbon). The isolated solids like the metal oxides, tar, carbon black etcetera are characterised by being the filler or additive accompanying the polymer depending on the manufacturer, being their proportions different. 
         [0012]    Another object of the present invention is the production of gaseous hydrocarbons, liquid hydrocarbons of high quality and solid products of high quality, and to reuse all the recovered products. Another object of the present invention is the use of said products in several determined applications. 
         [0013]    The liquid hydrocarbons for sale may be gasoline or diesel oil of different qualities. These products may have various applications and use. For example, they may be used as combustible for the co-generation of energy, in industrial and automobile engines, and in furnaces. Also, they may be used as feedstock in the chemical industry. 
         [0014]    The solid products for sale may be carbon black as well as the iron of the tires. The metallic products are sold directly while the carbon black may have various applications and use. Generally, it is used as a pigment or reinforcing material. It may also be used for asphaltic applications or mixtures, for the manufacture of master batches with polymeric products utilised in extrusions, injection and pressing of the plastics and rubbers or for its transformation into activated carbon. The activated carbon may then be used as a filtering agent or adsorbent in various applications of purification or also in medicine. 
         [0015]    Another object of the present invention is to provide an installation for carrying out the depolymerisation comprising one or more thermolysis reactors equipped with a cracking column in the upper part, means for purifying the obtained products, and means for providing energy to the installation using the thermolysis products. 
         [0016]    Another object of the present invention is to achieve the energetic autonomy of a recycling method by feeding the burner with the products of said recycling method. Preferably, the burner is fed with gaseous hydrocarbons. Alternatively, said burner may be additionally fed with liquid hydrocarbons and/or carbon black. The heat coming from the burner is utilised for heating the thermolysis reactor. 
         [0017]    Another object of the present invention is to achieve an increase in the production of carbon black, until reaching the double of the content of the carbon black that we had before. 
         [0018]    In the context of the present invention, the term “waste materials” means material that has been manufactured, used in industry or households and then thrown away or disposed of in any other way. However, it may also comprise materials that are leftovers of production processes or items of such a bad quality that they are directly thrown away after their manufacture. The waste materials may comprise residues of cables, old tires, containers of food products or household products, packaging or any other polymer-based material having a higher yield. Said waste materials are of use as starting material in the present invention. 
         [0019]    In the context of the present invention, the term “crack”, “cracked” or “cracking” refers to a thermal or catalytic chemical reaction which is normally used in the refining method of petroleum. “Cracked” or “cracking” means the decomposition or depolymerisation of the organic molecules, which preferably comprise long carbon chains, into smaller and/or shorter molecules. In the context of the present invention, the term “depolymerisation” means the decomposition of carbon chains in shorter fragments by either catalytically or thermally induced reactions. 
         [0020]    In the context of the present invention, the term “thermolysis” refers to a chemical reaction heat treatment wherein a compound is separated in at least two when subjected to a temperature increase, the compound not being in contact with the torch. Given that it is an endothermic reaction, the thermolysis requires the contribution of heat to break the chemical bonds. The decomposition temperature is set so that this process can take place. In the context of the present invention, the terms “cracking”, “depolymerisation”, and “thermolysis” may have the same meaning. 
         [0021]    In the context of the present invention, the term “secondary product” means a product of a reaction, process or method that results being a transformed compound for internal use or that needs being subjected to more processes or methods, preferably refining, to obtain a final product of high quality for external use and/or for sale. Hence, in the context of the present invention, the term “final product” means a refined product for external use which is suitable to be sold and/or used. 
         [0022]    In the context of the present invention, the term “material of organic nature” refers to materials, products or articles based on polymers. This “material of organic nature” may comprise synthetic or natural polymers, preferably synthetic polymers. More preferably, the “material of organic nature” comprises compounds showing a hydrocarbon structure with low oxygen content. The waste materials comprise materials of organic nature. 
         [0023]    The present invention is now further described by the annexed figures and claims. Like reference numerals indicate like elements. 
     
    
     
       FIGURES 
         [0024]    FIG.  1 —shows a general overview of the present invention. 
           [0025]    FIG.  2 —shows another general overview of the present invention. 
           [0026]    FIG.  3 —represents the main steps of the pre-treatment of the initial material. 
           [0027]    FIG.  4 —represents the main steps of the pre-treatment comprising the digestion in oil. 
           [0028]    FIG.  5 —shows another general overview of the present invention. 
           [0029]    FIG.  6 —represents the first steps of the refining of the gaseous and liquid hydrocarbons secondary products. 
           [0030]    FIG.  7 —represents the refining of the gaseous secondary products. 
           [0031]    FIG.  8 —represents the refining of the liquid secondary products. 
           [0032]    FIG.  9 —represents the refining of the solid secondary products. 
           [0033]    FIG.  10 —represents the refining of the solid secondary products comprising the dissolution in oil. 
           [0034]    FIG.  11 —represents a flow chart of the installation according to one embodiment. 
           [0035]    FIG.  12 —represents a flow chart of the installation according to another embodiment comprising the digestion in oil. 
           [0036]    FIG.  13 —represents a flow chart of the installation according to another embodiment comprising the dissolution in ether. 
           [0037]    FIG.  14 —represents a flow chart of the installation according to another embodiment comprising digestion in oil and dissolution in ether. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0038]    In the prior art recycling systems are described which are hardly efficient and result in secondary residue products containing an important stored energy value that is not reused. Moreover, some of these secondary products also are simply thrown away into the environment and an important source of energy is lost. Other systems simply burn the waste materials with all contained additives resulting in contaminant effluent gases. Other methods just consist in storing the waste materials in dumps and besides occupying large space they contaminate the environment. 
         [0039]    The present invention solves the above-mentioned problems and has additional advantages by providing a recycling method and system comprising the steps of:
       depolymerising polymer-based starting materials by thermolysis in a reactor, wherein the reactor is heated indirectly;   separating the solid, liquid and gaseous secondary products;   returning a part of the obtained secondary products to supply energy to the reactor; and   processing the remaining parts of the secondary products to manufacture final products suitable for external use;   wherein all the polymer-based starting material is either consumed by re-feeding to the reactor or refined to obtain solid, liquid and gaseous final products suitable for the consumption or sale.       
 
         [0045]    In all the described embodiments, it is understood that all described characteristics may be either method characteristics or characteristics describing the elements of an installation or system. Hence, in the description product characteristics as well as the necessary methodology to carry out the method for the product are disclosed interchangeably. If only a method is mentioned, it is understood that an apparatus, element, system, installation or means to carry out the method are also comprised in the description and it would be clear to the skilled in the art to derive one from the other. 
         [0046]    Referring to  FIG. 1 , in one embodiment, the method comprises the sequence of providing the starting materials  110 , the thermolysis  120  of said materials and isolating the thermolysis products  130 . 
         [0047]    As starting material  110 , any material of organic nature may be used that can be subjected to the depolymerisation. In one embodiment, the starting materials  110  comprise tires, rubbers, plastics, cables, cellulose, cellophane, nylon, oils, biological materials originating from plants or mixtures of the same. The tires are selected from the group comprising the ones commonly used in automation, transport and for industrial machines. The rubbers are selected from the group comprising natural, synthetic and reinforced rubber. In particular, the rubber may comprise butadiene, butadiene-styrene, chloroprene, elastomers, fluoroelastomers, and the like. Plastics are selected from the group comprising polyethylene, polypropylene and copolymers thereof, polybutylenetherephthalate, polyethylenetherephthalate, PVC, polystyrene, isobutylene-isoprene copolymer, polyisobutylene, and the like. It is understood that cables, cellophane and nylon are included in the plastics. The oils are selected from the group comprising oxidised oils, fuel oil, heavy oil, and the like. Preferably, tires, rubbers, plastics and liquid combustibles are used. More preferably, tires are used. All starting materials  110  previously treated may be subjected to the thermolysis  120  separately or mixed one with another. 
         [0048]    In one embodiment, by employing rubbers, 90% to 94% of their organic matter is transformed into liquid hydrocarbons of a density comprised between 0.74-0.79 g/cm 3 , being the rest gaseous hydrocarbons having 1 to 5 carbon atoms. In another embodiment, by employing tires all components may be recycled with the method and the installation disclosed herein. Said components comprise the metal core, carbon black (carbon black with high surface area), cotton, nylon and metal fabrics, mineral fillers (stabilisers), additives, oils and rubber. In another embodiment, derivatives of cellulose, methyl methacrylate or carbamides may be employed, where the yield can be different according to the content of their organic matter, producing in these cases more gaseous than liquid hydrocarbons. In another embodiment, a yield of 90% is obtained with the oxidised oils, the fuel oil and heavy petroleum without the production of fuel oil, decreasing its density between 0.2 g/cm 3  and 0.1 g/cm 3 , in accordance with the original density. The production of fuel oil is possible with the method herein disclosed but not planned, unless so desired. Moreover, it is noted that the fuel oil can be starting material as well as secondary product or final product. Without any doubt, use of the waste oils presents a very worthwhile method, which does not rule out pure or almost pure oils. 
         [0049]    As can be seen from  FIG. 2 , in one embodiment, a pre-treatment  210  of the starting materials  110  may be necessary when these are not provided in appropriate size and purity. 
         [0050]    The method and the installation may vary depending on the starting material  110 . 
         [0051]    In one embodiment, grinding and milling is performed, where the metal part is separated or not and the starting material (tires) is transformed with a catalytic and/or heat method into gaseous, liquids and semisolid hydrocarbons, such as waxes and tar, into carbon black and into inorganic oxides. In another embodiment, once milled, and with a catalytic and/or heat method, the starting materials (plastics) are cracked to obtain gaseous and liquid hydrocarbons and inorganic oxides. In another embodiment, for the cables, cellulose and nylon, the method may be a combination between the two previous embodiments. 
         [0052]      FIGS. 11 to 14  present overviews of embodiments of the present invention in more detail. 
       Pre-Treatment 
       [0053]    With reference to  FIG. 3 , the pre-treatment  210  is now explained in more detail. 
         [0054]    The starting materials  110 , preferably tires, rubbers plastics or oxidised oil, more preferably tires, have to be cut prior to thermolysis  120  when they cannot be provided in an appropriate size and/or purity. The preferred size of the solid starting materials is from 8 mm to 25 mm depending on the handling. A size smaller than 8 mm may still be useful for the present invention but results in higher costs making the recycling method less economical. A size greater than 25 mm is not useful because it still might contain greater metallic pieces. This metal on the one side could damage severely the joint elements between the distinct phases of the method and installation, and on the other side might involve a lower yield of the thermolysis products and a higher effort for purifying subsequently the solid secondary thermolysis products. 
         [0055]    The starting material  110  in its entirety or separately enters first a cutter device  301  having cross cutters or in any other geometrical form that is operated hydraulically or electrically. This cutter device  301 , for example a cutter, has the object to subdivide the material for a better transport. An ejector  302  of the “pusher” type of conventional functioning moves the material to a conveyer  303  that transports it to a hopper  304  located over a mill  305 . In this mill  305  of the shredder type, said material is further downsized by grinding to the preferred size of from 8 mm to 25 mm. In these mills  305 , shredder and hammer-type, the metals  313 , that the starting material  110  might contain, are eliminated, especially the iron of the tire. Also, the fabric components may be eliminated in the case they would be present in the starting material  110 . 
         [0056]    Subsequently, the material in pieces is washed with water  306  to remove impurities deposited on the surface. Such impurities may be sand, silica, dust or the like. The washing water  306  is collected and transported to a recipient where it is decanted and the impurities are removed by filtering them off. The clean water is then stored in a deposit tank and can be re-used for washing  306  of fresh starting material  110 . The solid impurities are removed into a container. 
         [0057]    The wet starting material  110  then passes to a drying area  307 . Said material is fed to the drying  307  by a screw conveyer having a slow velocity and a variable pitch. The drying area  307  is fed by two currents, one of hot air proceeding from the combustion chamber and the other of regeneration air originating from the blower. Thus, a drying  307  may be performed faster and more efficiently given that with two gas currents no water vapour saturation occurs in the air. Both currents, after passing and drying the wet material, are evacuated to the chimney using another blower to the recovering chimney of carbonate anhydride. 
         [0058]    After drying, the material passes to a vibrating platform  308  where the remaining impurities are separated due to the different densities. Then, the material is transported on a magnetised conveyer  309  where in its final part it is demagnetised for removing the possible iron  314  that had remained in the material. The so obtained starting material  110  is free of impurities and metal components and stored  310  in containers, big-bags or in storage silos, preferably in storage silos, prior to thermolysis  120 . 
         [0059]    In one embodiment, this storage silo contains in its bottom industrial planetary extractors, ideal for continuous use and formed by:
       a metallic beam diametric to the silo which contains all the necessary mechanisms for the rotation of the extraction bucket;   a central conical hood wherein the engines for the rotation of the bucket are installed and protected;   the pinions, the chains, the transmission organs and the running-in which guarantee the necessary working pairs, movements and turns to the extraction bucket;   conic frustum extraction bucket system having a shaft and spiral duly dimensioned for extracting the product towards the silo and empty it into the central metallic discharge hopper, with a condenser probe for protection against inundations (formation of vaults) in the hopper.       
 
         [0064]    In one embodiment, just before feeding the treated starting material to the reactor, a conventional cracking catalyst  311  may be added and the air is removed  312  and replaced by an inert atmosphere. The catalyst permits performing a thermolysis method at lower temperatures and shorter reaction times than without such a catalyst. Furthermore, the catalyst favours the yield and reduces the undesired secondary products. However, the person skilled in the art will know that it is also possible to add the catalyst to the reactor. An inert atmosphere is necessary to avoid any detrimental oxidation reactions of the desired secondary products that might cause a reduction of the quality or, in the worst case, fires or explosions. 
         [0065]    In this way, the main pre-treatment method  210  is finalised. Said pre-treatment may be appreciated also from the  FIGS. 11 to 14 , where the starting material enters the installation in  110 , passes the afore-mentioned steps and is stored in  310 . 
         [0066]    In an alternative embodiment, as can be appreciated from  FIG. 4 , the starting material  110  is transported after the drying  307  to a digester device  401  where said materials are mixed with oil  402  previously heated to a temperature of from 50° C. to 350° C. in said digester  401 . The necessary heat may be provided from the hot air proceeding from the combustion chamber. The mixing with the hot oil  402  causes the initial material to swell and become spongy, resulting in the debonding and separation of the metal components from said material. This method may further benefit from the use of a stirring means. The digestion carried out depends on the temperature of the hot oil and the type of initial material and may vary typically between 15 minutes and 60 minutes. Supernatant oil  404  is then recovered either for subsequent digestions or as optional additive for the thermolysis  120 . The starting material  110 , impregnated with oil, leaves the digester  401  through an exit in the bottom and is discharged on a magnetic conveyor  404  which serves to separate the metal  405  and to filter off the remaining oil  406 . Finally, the initial material is stored  310  prior to thermolysis  120 . Said storing may be made in a storage silo or directly in the hopper that feeds the reactor. This may depend on the amount of starting material to be treated. The main advantage of this embodiment is that the step of digestion in oil allows softening of the primary material mass, allowing a more efficient, and thus faster, reaction. Another advantage is that filtering of metal component remains of reduced size is allowed, since they may be separated more easily from the mass. 
         [0067]    The digester  401  comprises a hopper, a stirrer operated by an engine, a gas exit, an entry for adding the oil, an exit in the bottom for transporting the starting material  110  and an exit at liquid level to recover the supernatant oil  404 . 
         [0068]    This alternative embodiment may also be appreciated in the diagrams of the  FIGS. 12 and 14 , wherein the digester  401  is indicated. 
       Thermolysis 
       [0069]    With reference to  FIG. 5 , having prepared the material  110  for the thermolysis  120  it may be added to the hopper feeding the reactor either from the storage silo or, if the pre-treatment  210  is not necessary, directly from big-bags through a blower and a rotary valve. In said hopper, said catalyst is added and the air is expelled. The expelled air, coming from the blower, is filtered by a sleeve filter to comply with the environmental law. The content of the hopper is then charged into the reactor and thermolysis  120  can start. 
         [0070]    The reactor is located inside a heat system, preferably a heating jacket, which is able to provide indirect heating along the reactor. The heat is produced in a burner or combustion chamber to which mainly gaseous hydrocarbons are fed. However, also liquid hydrocarbons and/or carbon black may be used as combustibles. Said heat is brought towards the reactor by pipes. In one embodiment, the burner is fed with gaseous hydrocarbons, liquid hydrocarbons not having the desired quality for their subsequent external use and carbon black not having the desired quality for its subsequent external use. Hence, it is possible to burn three different components at the same time in the same triple burner. In one embodiment, said triple burner is fed with about 80% of gaseous hydrocarbons, about 10% of liquid hydrocarbons and about 10% of carbon black. The triple burner can be operated to heat one or more reactors. In one embodiment, from one to six thermolysis reactors may be heated at the same time using said triple burner. 
         [0071]    The combustion air has a temperature which normally is too high for the purposes of the present invention due to the high energetic content of the combustibles. Hence, the combustion air to be used for heating of the thermolysis has to be controlled. 
         [0072]    The heating temperature is regulated by adding an appropriate amount of air having a temperature lower than the necessary thermolysis temperature to the combustion air. Preferably, said air has ambient temperature. The desired temperature is controlled by various sensor means outside and inside the reactor. 
         [0073]    Said reactor may be vertical, horizontal or inclined. In the upper part, the reactor may comprise various inlets, such as for example for the stirrer means, starting material, addition of additives when necessary, preferably oil, or sensor means to control temperature, pressure, oxygen content, etcetera, pressure control valve and the like. In one embodiment, the reactor is vertical. The secondary products can be extracted faster with a vertical reactor than with other configurations given that the path of the secondary product to the exit is shorter and that the principle of gravity may be used. Moreover, it is possible to build the installation in modules from bottom to top in a smaller room to place advantageously more than one reactor, together with the respective peripheral means that also require an indirect heating, in one single heating jacket. Another advantage consists in that the combination of the vertical reactor with the cracking column results in a higher effective height of the column where the molecular cracking is realised. This height allows for a faster and more efficient overall reaction. 
         [0074]    In one embodiment, at least one reactor is used to carry out the thermolysis  120 . However, the triple burner is able to heat between one and six reactors at the same time. Hence, more than one reactor may be used with which it becomes possible to treat more starting material or make the thermolysis faster and more efficient. 
         [0075]    In one embodiment, a starting material  110  is mixed with oxidised oils  550 . The oxidised oils  550  may be added already in a pre-treatment  210  or added directly to the reactor as additives. Said oil may be added if it is desired to change the result of the secondary product  510  of the thermolysis  120  of a certain starting material  110 . The addition  550  may be in the range of about 3% to about 30% by weight, preferably from 5% to 15% by weight, of the total weight of starting material  110  introduced. It has been found that the addition of oil  550  allows controlling the composition and the yield of the final products with the advantage that, in case of starting material  110  of an unfavourable composition, for example a low light hydrocarbons result may be compensated by adding said oil. However, more than 30% by weight of oil gives as result a too high percentage of heavy hydrocarbons and is not desireable. 
         [0076]    The reactor also comprises several exits such as for example for extraction of the products of the thermolysis. In the upper part of the reactor, there is placed a cracking column through which the resulting thermolysis gas comprising gaseous and liquid hydrocarbons leaves the reactor. In the lower part of the reactor, an exit valve is provided through which the solid secondary product  540  of the thermolysis  120  passes on to the drying device. In one embodiment, the exit valve is located in the bottom of the reactor and the solid secondary product  540  of the thermolysis  120  falls into the drying device. 
         [0077]    As afore-mentioned, in one embodiment the thermolysis reaction may preferably be carried out in an inert atmosphere in presence of a catalyst. 
         [0078]    The catalyst allows a thermolysis method being carried out at lower temperature and reaction times than without said catalyst. Moreover, the catalyst favours the yield and reduces undesired secondary products  510 . However, the person skilled in the art knows that it is also possible to add the catalyst to the reactor. The inert atmosphere is necessary to avoid prejudicial oxidation reactions of the desired secondary products that might cause a decrease of the quality or, in the worst case, cause a fire or explosion. 
         [0079]    Any conventional thermolysis or cracking catalyst may be used. In one embodiment, the catalyst amount depends on whether the starting material  110  already contains a certain quantity of said catalyst or not. In one embodiment, less than 0.1% of catalyst is used, preferably between 0.05% and 0.1% of organic and inorganic compounds comprising calcium and/or zinc. In any case, the catalyst amount is maintained low with the corresponding advantage that it is not necessary to carry out an additional separation step when purifying the solid product of the thermolysis. 
         [0080]    The thermolysis temperature is preferably in the range of from 150° C. to 450° C. Said temperature is controlled on the one hand by the sensor means regulating the triple burner and on the other hand by using stirrer means inside the reactor. Said stirrer means are fixed vertically in the reactor, preferably fixed in the upper part of the reactor. Said stirrer is used to distribute the heat over the reactor and the reaction mixture as well as to homogenise said reaction mixture. By distributing the heat, the stirrer provides a uniform and constant temperature distribution over the whole mass and makes the mixture of the starting material homogeneous allowing a more efficient thermolysis reaction. Undesired side reactions or unpredictable product compositions may so also be prevented. 
         [0081]    The stirrer means are controlled to operate at determined velocities which are necessary for an efficient thermolysis method. In one embodiment, the velocity of the stirrer is from 5 rpm to 50 rpm (rounds per minute). If the velocity is lower than 5 rpm, the starting material mixture is not stirred appropriately and no homogeneity is achieved resulting in a lower yield. If the velocity is higher than 50 rpm, the starting material mixture is stirred too vigorously and will stick to the walls of the reactor resulting in a lower yield. 
         [0082]    During thermolysis  120 , various secondary products  510  are formed. The secondary products  510  of highest quantity are hydrocarbons. These may be light or heavy gaseous hydrocarbons, paraffins, isoparaffins, olefins, naphtha, kerosene, gasoline and diesel oil. Usually, a mixture of these hydrocarbons is formed that has to be purified and separated. Under thermolysis conditions, mainly all hydrocarbons are in a gaseous state and form the thermolysis gas, although a small part of the heavy hydrocarbons formed cannot vaporise and remains in liquid form in the reactor. Moreover, other small molecules may be formed, as for example water, hydrogen, carbon dioxide and the like that will also be present in the gaseous state. This gaseous mixture comprises the thermolysis gas formed during the thermolysis  120 . Moreover, solid secondary products  540  will form, mainly in the form of carbon black. Also, the inorganic compounds which were added to the starting materials  110  as additives and the residues of the catalyst will be part of the solid secondary product  540  and have to be removed during a subsequent refining method. Usually, the liquid heavy hydrocarbons that remain will adsorb to the carbon black due to its porous structure. Hence, a subsequent separation step has to be carried out. 
       Refining 
       [0083]    With reference to  FIG. 6 , during the thermolysis  120  a thermolysis gas  610  is produced comprising hydrocarbons which at ambient pressure and ambient temperature will be in gaseous and/or liquid state. Moreover, there may also be other small molecules present produced during the thermolysis  120  in said thermolysis gas  610 , like for example hydrogen, water and the like. Said thermolysis gas  610  leaves continuously the reactor in the upper part of the reactor where the cracking column  620  is located. 
         [0084]    The column  620  may present one or more exits along its length to remove selectively different types of hydrocarbons depending on their boiling point. In one embodiment, there is only one exit at the end of the column  620  for removing the final hydrocarbons formed. Hence, the thermolysis gas  610  has to pass through the whole column  620 . 
         [0085]    Said column  620  disposes of several plates in its interior which cause a further cracking  630  of the hydrocarbons. The plates are installed in series over the whole column  620  and form a set of plates that have a grating supported on a metal ring from which is hanging a sheet provided with holes. The set of plates forms a structure in the interior of the column  620  in such a manner that said collection is supported by a threaded bar passing through central openings and which bar has positioned in its upper part a sheet that is open in its interior provided with a central opening. The plates are formed by various conic frustrum tips exiting from the inner surface of the column  620  having different inclination angles. Moreover, said plates consist of some cartridges formed by a series of trays gradually superposed. Said trays are usually to about 75% superposed one over another. Moreover, each tray shows a series of staggered small cylindrical holes. It has been found that the structure of said sheets serves for cracking  630  and the fractioning distillation of the hydrocarbons to enrich determined hydrocarbons having between 5 to 15 carbon atoms and further to separate the carbon black particles that may be dragged with the current of the thermolysis gas  610  leaving the reactor. 
         [0086]    In one embodiment, part or all of the thermolysis gas  610  leaving the cracking column  620  may be returned to said column  620 . This may be possible before or after passing a decanter preconnected to the condenser having the effect of a filter and separating the dragged carbon black particles. All the hydrocarbons formed may be redirected without the temperature dropping too much, thereby not affecting the cracking of the recent formed thermolysis gas. Thus, the thermolysis gas  610  comprises a high proportion of hydrocarbons with a carbon atom number of between 5 to 15, in its majority saturated hydrocarbons and aromatics with few heavy hydrocarbons present. The plates inside the column  620  have the effect of condensing and vaporising the organic molecules over and over again at the thermolysis temperature inducing a thermal cracking  630  resulting finally in a desired hydrocarbon composition. The thermal cracking  630  occurs mainly with the heavier hydrocarbons due to their higher boiling point while the lighter hydrocarbons pass faster through the column  620 . Hence, mainly hydrocarbons having a carbon atom number between 5 to 15 are formed. 
       Gaseous Secondary Products 
       [0087]    As can be appreciated from the  FIG. 7 , after leaving the cracking column  620  the cracked thermolysis gas  610  enters into a condenser  701 . A refrigerating system which is part of the condenser  701  is set into operation so that it allows separating the gaseous hydrocarbons  520  having a carbon atom number of 1 to 4 from the liquid secondary hydrocarbons  530  having a carbon atom number higher than 4. Any condenser known in the art may be used. The refining of the so obtained liquid secondary hydrocarbons  530  is described in the following. 
         [0088]    The gaseous hydrocarbons  520  separated in the condenser  701  comprise mainly hydrocarbons having a carbon atom number of from 1 to 4 and may additionally comprise hydrogen. The main components of said gaseous hydrocarbons  520  are methane, ethane, ethylene, propane, propylene, butane and isobutene and some light mercaptane. After leaving the condenser  701 , the isolated gaseous hydrocarbons  520  are washed  702  to remove sulphur and chlorine ions and are finally stored  703  in, for example, a gasometer. The so obtained combustible gas may be used for the combustion in the triple burner  710  and establish the energetic autonomy of the installation. In one embodiment, the combustible gas may be introduced into the municipal gas supply network or otherwise be sold, for example as feedstock for polymer industry. 
       Liquid Secondary Products 
       [0089]    In one embodiment, said desired liquid light hydrocarbons  530  comprise the hydrocarbons having a carbon atom number of from 5 to 15, mainly saturated and/or aromatic. In another embodiment, said hydrocarbons have a carbon atom number of from 5 to 12. The components of said hydrocarbons may be of the type of paraffins, isoparaffins, olefins, naphtha, kerosene, gasoline or diesel depending on the starting material used. For example, tires will produce more synthetic diesel while plastics will give naphtha and kerosene. 
         [0090]    The refining of the liquid hydrocarbons is shown in  FIG. 8 . After the condenser  701 , where the gaseous hydrocarbons are separated, the liquid hydrocarbons pass on to the decanter  810 . The aim of the decanter is to separate the desired light hydrocarbons  811  from the heavy hydrocarbons  812  and from water  813 . Any decanter known in the art may be used. The desired light hydrocarbons  811  are further processed and the water  813  and the heavy hydrocarbons  812  are collected each separately. 
         [0091]    In one embodiment, part or all of the liquid hydrocarbons  530  are returned to the cracking column  620 . This may be possible before or after passing the decanter  810 . So, it is possible to redirect heavy  812  and light  811  hydrocarbons together or only the light hydrocarbons  811 . Returning the liquid hydrocarbons  530  is necessary to guarantee that the final liquid product comprises hydrocarbons having a carbon atom number of between 5 and 15, in its majority saturated and aromatic hydrocarbons and of high quality without containing substantially any heavy hydrocarbon  812 . When the liquid hydrocarbons  530  are returned to the column  620 , they are heated to the thermolysis temperature and have to pass again through the whole cracking column  620 . The effect of the plates of condensing and vaporising the organic molecules over and over again at the thermolysis temperature induces a thermal cracking  630  resulting finally in the desired hydrocarbon fractions. The thermal cracking  630  occurs mainly with the heavier hydrocarbons due to their higher boiling point while the lighter hydrocarbons pass faster through the column  620 . Thus, said hydrocarbons having a carbon atom number of between 5 and 15 are enriched. Another advantage consists in reducing the amount of solid particles possibly dragged with by the thermolysis gas  610  and the final purification will be less laborious. 
         [0092]    The final refining method of the light hydrocarbons  811  is as follows. After leaving the decanter  810 , the light hydrocarbons  811  are washed  815 , filtered  816  and centrifuged  817 . In one embodiment, the so isolated light hydrocarbons  811  are then stored  818  for their sale  820  and/or use  830 . The devices and techniques known in the art may be used. 
         [0093]    In one embodiment, after leaving the centrifuge, part or all of the obtained liquid light hydrocarbons pass through a second column having conventional plates. In contrast to the cracking column  620  serving for the cracking of the thermolysis gas or the liquid hydrocarbons  530 , this column has various exits with the effect that different fractions may be isolated and mixed to obtain a selectable diesel composition. Another effect is enriching the liquid light hydrocarbons in molecules having a carbon atom number between 5 and 12 and producing the desired diesel. It serves also as a purification step and it may be that heavy hydrocarbons still present will be separated. Said second column may be appreciated, for example, in the  FIG. 11  indicated as  1101 . 
         [0094]    They may be used as such or can be blended with gasoline or diesel. In one embodiment, the light hydrocarbons may be used as combustible  831  in burners and industrial and automobile engines or to cogenerate energy  833  if desired. They may also be used as feedstock  832  or solvents in the chemical industry. In one embodiment, the light hydrocarbons may be used as combustible  831  for the triple burner to maintain the energetic autonomy of the plant when necessary. 
         [0095]    In one embodiment, the heavy hydrocarbons  812  due to their poor quality are fed to the triple burner and contribute in this way to the energetic autonomy of the plant. 
       Solid Secondary Products 
       [0096]    With reference to  FIG. 9 , when the thermolysis  120  has finished, the solid secondary products  540  of the thermolysis  120 , preferably carbon black, remain in the reactor. Said solid secondary products  540  of the thermolysis  120  may be mixed with some liquid products of the thermolysis  120  which have not vaporized under the thermolysis conditions. Said liquid secondary products  530  of the thermolysis  120  normally tend to be adsorbed on the solid secondary products  540  of the thermolysis  120  and must be removed by drying  902 , such as described subsequently. 
         [0097]    The solid secondary products  540  of the thermolysis  120  are removed  901  from the reactor through an exit valve located in the lower part of the reactor. Preferably, said valve is located in the bottom of the reactor. So, when the thermolysis  120  has finished, said exit valve is opened and the solid secondary product  540  falls into the drying device  902 . Once the reactor is emptied, the exit valve of the lower part of the reactor is closed and fresh starting material  110  may be added to the reactor to initiate another thermolysis reaction. Hence, the thermolysis of the present invention is carried out in a discontinuous manner. 
         [0098]    The additional liquid secondary products  540  of the thermolysis  120  that have not vaporised and now are adsorbed on the solid secondary products  540  of the thermoplysis  120  comprise preferably heavy hydrocarbons  812 . Said heavy hydrocarbons  812  may be removed applying sufficient heat during a determined time so that finally they vaporise and separate from the solid. This is carried out in a drying device  902 , preferably located below the reactor. In this way, said drying device  902  is located within the same heating system as the thermolysis reactor and may benefit from the same indirect heating which is used for the thermolysis  120 . In one embodiment, the drying device  902  is equipped with stirrer means that distribute the not dry carbon black over the whole dryer  902  which provides a better and faster removal of the adsorbed hydrocarbons. 
         [0099]    After having desorbed from the solid secondary product  540 , the heavy hydrocarbons  812  leave the drying device  902  through an exit in the upper part of the device, preferably in the ceiling, and may be collected in a separate deposit together with the heavy hydrocarbons isolated in the decanter  810 . The substantially dry solid secondary products  540  leave the drying device  902  through an exit in the lower part of said device, preferably in the bottom. 
         [0100]    Said solids  540  will then be transported by transportation means, preferably in form of a screw. Said screw may be covered by a heat system that may be the same or a different heat system than the one used for heating the reactor and the drying device  902 . Said heat system keeps the substantially dry solid secondary products  540  at temperatures of from 130° C. to 350° C., preferably 150° C. to 270° C. This will allow removing the liquid residues that might still be adsorbed on the solid secondary products  540 . At the end of said screw, all volatiles substances will exit through an exit leading to the deposit where the heavy hydrocarbons  812  are collected. 
         [0101]    The now dry solid secondary products  540  are then cooled to ambient temperature by cooling means  906  for their subsequent purification. In one embodiment, the cooling means  906  comprise a platform with a heat exchanger system. The heat exchanger system might be operated with any medium, preferably cool air, water or other liquids, more preferably with water. The temperature of the cooling medium may be ambient temperature or lower. Other methods of the state of the art perform said cooling later in the refining with the disadvantage that the systems between exiting the reactor and cooling device require thermally strong and durable construction elements. The cooling prior to the purification steps allows the use of cheaper devices and where the maintenance is easier. Moreover, purification agents such as washing baths in different solvents may be used directly, something that would not be possible at elevated temperatures without taking certain precautions. 
         [0102]    The platform  906 , further to the heat exchange system, comprises a vibrating conveyer belt having various elevated elements on its surface that render said surface of the platform  906  irregular. Said elements are distributed all over the platform  906  and may be provided regularly or irregularly. Preferably, the elements are provided regularly, lined up or staggered. The height of said elements is not limited, as long as the possibility exists that the carbon black can pass above said elements. Preferably, said elements have the shape of a button. Said elements impart a higher surface area to said platform  906  making the cooling process more efficient given that the carbon black may be brought into contact with more cooling area. Said elements also make that the carbon black becomes spongier. The advantage thereof is a faster sieving since a material rendered spongy does not tend to become compressed. 
         [0103]    After leaving said platform, the carbon black is sifted  907  to eliminate any impurity possibly remaining from the original starting material  110  such as for example cracking residues having an elevated fusion point that might not have suffered complete thermolysis  120 . Next, the sifted carbon black may be washed in aqueous acid solution to eliminate the inorganic impurities  908  and the catalyst traces still present, or it may be milled  911  subsequently in microniser until a uniform average particle size. These two steps are interchangeable. For example, in one embodiment according to  FIG. 9 , first the removal of the inorganic particles is carried out and then the carbon black is milled, while in another embodiment, the step of milling is carried out before the removal of the inorganic particles. The so obtained carbon black is then stored for sale. 
         [0104]    In one embodiment, the carbon black is used for asphaltic applications  931  or to manufacture master-batches  932  with polymeric products used in extrusion, injection and pressing of plastics and rubbers. Another of its applications is the use for fireworks  933 . The carbon black may also be transformed into activated carbon  934  for its use as filter or absorption agent or for medical applications. It also has use in the production of new tyres, as a pigment  935 , or as a reforcing material  936 . 
         [0105]    In one embodiment, the carbon black that has not the desired appropriate quality may be separated and fed to the triple burner  710 , such as described before. 
         [0106]    In one alternative embodiment, as can be appreciated from  FIG. 10 , the solid secondary products  540  resulting from the thermolysis  120  may be continuously removed from the reactor by a dissolution phase in ether and using a screw or the like. Said screw is located in the lower part of the reactor. Inert atmosphere is maintained. The solid secondary product  540  is kept at temperatures of from 130° C. to 350° C., preferably 150° C. to 270° C., using a heat exchanger. Said solid secondary products  540  are transported to a decanter tank  1002  where the adsorbed liquid secondary products  530  to said solid are separated and returned to the reactor using a pump. The step of dissolution in ether has the effect to liquidise the secondary products allowing a quicker separation. 
         [0107]    Then, the inorganic impurities are separated. Therefore, said solid is transported to a recipient having a stirrer where an organic solvent is added  1004  comprising an ether group, preferably dietyl ether or diisopropyl ether. The organic portion, preferably heavy hydrocarbons  812 , of said solids will dissolve in the solvent and carry away the carbon black while the inorganic portion will settle forming a suspension. After that, the inorganic substances  1012  may be decanted off. This separation method is normally performed at temperatures of from −70° C. to 20° C. The ether phase  1005  comprising the carbon black is transported to a first distillation device  1006  where the ether is removed  1013  by distillation and collected in a deposit for re-use in the later purification of fresh secondary solid products  540  of the thermolysis  120 . The still remaining hydrocarbons  812  are also removed and then returned to the thermolysis reactor. The carbon black  1007  to which still some ether is adsorbed to is transported to a second distillation device wherein a flash distillation  1008  is carried out by introducing a current of inert gas previously heated in a heat exchanger fed by the gases coming from the combustion chamber  710 . The effect of the flash distillation  1008  is the separation of the ether residues  1013  which leave by the head after passing a filter, typically a sleeve filter, and are returned to the first distillation device  1006 . The dry carbon black  1009  is collected at the bottom of the second distillation device and falls through an exit in the bottom of said distillation device into a recipient where it is further treated as described before. 
       EXAMPLES 
       [0108]    The following tables show the results of different recycling methods obtained with different starting materials: 
         [0000]    
       
         
               
               
               
               
               
             
               
             
               
               
               
               
               
             
               
             
               
               
               
               
               
             
               
             
               
               
               
               
               
             
               
             
               
               
               
               
               
             
           
               
                   
               
               
                   
                   
                   
                   
                 % over 
               
               
                 Starting Material: 
                 kg 
                 Products 
                 kg 
                 org. mat. 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1. - Thermolysis of a plastic or a rubber without filler: Yield 98% 
               
             
          
           
               
                 plastic/rubber 
                 100 
                 gaseous hydrocarbons 
                 6.0 
                 6.1 
               
               
                   
                   
                 light hydrocarbons 
                 87.0 
                 88.9 
               
               
                   
                   
                 heavy hydrocarbons 
                 4.8 
                 4.9 
               
               
                   
                   
                 inorganics (oxides) 
                 0.2 
               
             
          
           
               
                 2. - Thermolysis of a filled plastic: Yield 98% 
               
             
          
           
               
                 plastic filled at 20% 
                 100 
                 gaseous hydrocarbons 
                 7.0 
                 9.4 
               
               
                   
                   
                 light hydrocarbons 
                 62.0 
                 82.5 
               
               
                   
                   
                 heavy hydrocarbons 
                 6.0 
                 8.1 
               
               
                   
                   
                 inorganics (oxides) 
                 23.0 
               
             
          
           
               
                 3. - Thermolysis of tires Yield 98% 
               
             
          
           
               
                 tires 
                 100 
                 Metals 
                 14.0 
                   
               
               
                   
                   
                 gaseous hydrocarbons 
                 7.0 
                 8.5 
               
               
                   
                   
                 light hydrocarbons 
                 19.0 
                 23.1 
               
               
                   
                   
                 heavy hydrocarbons 
                 14.0 
                 17.1 
               
               
                   
                   
                 inorganics (oxides) 
                 4.0 
               
               
                   
                   
                 carbon black 
                 42.0 
                 51.2 
               
             
          
           
               
                 4. - Thermolysis of oxidised oils Yield 96% 
               
             
          
           
               
                 oxidised oils 
                 100 
                 gaseous hydrocarbons 
                 3.0 
                 3.1 
               
               
                   
                   
                 light hydrocarbons 
                 25.0 
                 26.0 
               
               
                   
                   
                 heavy hydrocarbons 
                 68.0 
                 70.1 
               
               
                   
               
             
          
         
       
     
         [0109]    As can be deduced from the results of the practical experiments carried out, the method and installation allow advantageously the production of carbon black in a higher quantity than originally exists in the starting material. The composition in carbon black in the tires for cars and trucks, which are the ones that are most abundant, is for the car of 13% to 17% and for truck tyre between 25% and 30%, these quantities vary depending on the manufacturer. Therefore, as average, the tires which are recycled have 20% of carbon black as content. As can be observed in section 3 of the example, the increase of carbon black is more than the double of its initial content. In this case, it is possible to extract about 52% of carbon black. Therefore, the characteristics of the invention allow the efficient rectification of the starting materials allowing its entire recycling and so increasing the quantity of produced carbon black.