METHOD AND PLANT FOR DISPOSING OF WASTES COMPOSED OF PLASTIC MATERIALS AND BIOMASSES

Abstract

A pyrolysis plant for the treatment of solid and liquid waste materials is described, comprising: a first section (100), suitable for carrying out a pyrolysis of this solid and liquid waste materials, this pyrolysis producing synthesis gas, syngas, and residual ash; a second section (200) adapted to carry out a separation of the lighter fraction of this ash, coal dust or carbon black, from the syngas, the lighter fraction being transported by the syngas; a third section (300), suitable for carrying out a fractional distillation of the syngas, obtaining the separation of the volatile fraction of the syngas from a bituminous residue, tar; a fourth section (400), adapted to carry out a recycling of the bituminous residue of the fractional distillation, for a further treatment; and a fifth final emergency section, including, in addition to safety pumps which will automatically intervene in the event of a system failure, all safety systems.

Claims

1-14. (canceled)

15. A pyrolysis plant for the treatment of solid and liquid waste materials, comprising: a first section, suitable for carrying out a pyrolysis of the solid and liquid waste materials, the pyrolysis producing synthesis gas, syngas, and residual ash; a second section adapted to carry out a separation of a lighter fraction of the ash, of coal dust or carbon black, from the syngas, the lighter fraction being transported by the syngas; a third section, suitable for carrying out a fractional distillation of the syngas, obtaining a separation of a volatile fraction of the syngas from a bituminous residue, tar; a fourth section, adapted to carry out a recycling of the bituminous residue of the fractional distillation, for a further treatment; and a fifth final emergency section, the final section including, in addition to safety pumps that will automatically intervene in the event of a system failure, all necessary safety systems for dealing with an emergency, wherein the first section, suitable for carrying out the pyrolysis of the solid and liquid waste materials, comprises a cylinder, or pyrolysis chamber, rotating around its own axis and provided with: external insulation; means able to cause, by means of the rotation, the advancement of the material contained in the cylinder, the means able to cause, by means of the rotation, the advancement of the material contained in the cylinder, comprising an Archimedes screw; solid waste loading means positioned at a first end of the pyrolysis cylinder; heating means, the heating means comprising at least one radio frequency induction generator, each of the generators being connected to a coil, inside which the pyrolysis cylinder rotates slowly, the coil transmitting the high frequency induced current created by the at least one generator in such a way that the pyrolysis cylinder becomes the seat of eddy currents which heat it by the Joule effect; means for rotating the cylinder.

16. The pyrolysis plant of claim 1, wherein the means for rotating the cylinder comprise a first motor-reducer unit, and the means for loading solid waste, positioned at the first end of the pyrolysis cylinder, comprise an auger, fed by a hopper and rotated by a second motor-reduction unit.

17. The pyrolysis plant of claim 2, wherein the screw feeds the solid waste with a compression ratio of approximately 1:200 and is preheated to a suitable temperature, depending on the type of waste, to allow forming a cap to prevent both syngas leaks and oxygen infiltrations in the pyrolysis chamber.

18. The pyrolysis plant of claim 1, wherein the second section, suitable for carrying out the separation of the lighter fraction of the ash, coal dust or carbon black, from the syngas, comprises a quenching chamber in which the syngas coming out of the pyrolysis chamber is collected, at least one duct being provided for conveying the syngas towards at least one cyclone inside which the syngas is treated in such a way as to carry out the separation from the coal dust, carbon black, transported by the syngas, the dust being discharged through a lower opening of the at least one cyclone, while from the upper part the thus purified syngas is released.

19. The pyrolysis plant of claim 1, wherein the third section, suitable for carrying out the fractional distillation of the syngas, comprises a column, comprising: ducts, positioned in the lower part of the column, through which the syngas coming from the separator cyclones enters; an outlet, positioned in the upper part of the column, from which the syngas comes out after separation from the bituminous residue, tar, the syngas being conveyed towards a blower capable of creating a slight depression in the chamber pyrolysis and to send the syngas towards the washing columns; an outlet, positioned in the lower part of the column, from which the bituminous residue comes out; wherein the fractional distillation column further comprises a duct, which enters the upper part of the column, into which cooling water is passed, the water crossing a coil and exiting, in the form of superheated steam, from a duct.

20. The pyrolysis plant of claim 1, wherein the fourth section, adapted to carry out the recycling of the bituminous residue of the fractional distillation, comprises: a turbo-mixer, driven by a third motor-reduction unit, into which the bituminous residue is inserted; a duct, through which carbon black coming from the cyclones is inserted into the turbo-mixer; a duct, through which liquid waste, vegetable oils and exhausted fats, are inserted into the turbo-mixer; wherein, in the turbo-mixer, an emulsion is produced which is inserted into the pyrolysis chamber; and, wherein the fourth section further comprises a conduit through which the superheated steam coming from the fractional distillation column is introduced into the pyrolysis chamber, through the conduit.

21. A pyrolysis plant for the disposal of waste consisting of plastic materials or biomass, and of all organic materials that contain carbon in their molecules, the plant including: a waste feeding system; and the pyrolysis plant of claim 1, wherein the first section is operationally connected to the waste feeding system and consists of a concentric cylinder made of bimetallic material equipped with an Archimedes screw, the cylinder being externally insulated and slowly rotating around its own axis, the cylinder being operatively connected to the second section.

22. The pyrolysis plant of claim 7, wherein the first section comprises a reactor heated by two or more induced current generators with a frequency between 1.5 and 5 KHz so that the cylinder becomes the seat of eddy currents designed to heat it by the Joule effect and bring the temperatures inside the reactor between 650 and 750? C. at which the pyrolysis process takes place, each of the generators being connected to a coil inside which the cylinder rotates with a speed determined by the PLC and calculated by the PLC according to the transformation times of the individual matrices introduced, the cylinder having a diameter between 1200 and 1500 mm and a length between 9 and 12 m, and being equipped with a system controlled by a gear motor suitable for its rotation as well as a system suitable for absorbing the expansion due to temperatures, the cylinder, in its ends, being insulated with a packing housed in a groove and kept under pressure by a series of springs and also having a second nitrogen gas safety insulation system, inside the cylinder, with continuous temperature control by means of thermocouples and laser probes as well as a control of the internal pressures which, by means of a system of vacuum pumps, keeps the cylinder and the final stilling chamber at a slight depression, of about 0.7 mbar, with respect to the external atmospheric pressure, the cylinder and the heating and movement and control systems being placed inside a Faraday cage to isolate the outside from internal induced currents.

23. The pyrolysis plant of claim 7, wherein the second section, suitable for receiving the syngas from the cylinder, consists of a stilling chamber where the thermochemical reactions induced by the radio-magnetic waves take place, and syngas and lighter fractions are separated from ashes, the calm or ionic coupling chamber being equipped with a system of augers for the extraction of ashes, the augers controlled by PLC remaining constantly full of ash which it acts as a cap to prevent the escape of gases and the entry of external air, in the final part being equipped with a one-way safety valve.

24. The pyrolysis plant of claim 7, wherein the third cooling and distillation section of the syngas is designed to separate the syngas into a condensable part and a solid part by means of a distillation column and a centrifugal separator, the third section being also equipped with a refrigeration plant or an ORC system for recovering and transforming heat into energy, the centrifugal separator dividing the condensed products and solids from the cooling water, to then send the condensed and divided products at the beginning of the cycle for a second distillation, or the separated products will be stored for their industrial use.

25. The pyrolysis plant of claim 7, wherein the fourth washing section, suitable for receiving the syngas cooled below 80? C., is designed, by means of two cooling towers containing a mixture water, the first one slightly acidic and the second one weakly basic, to provide, as well as a further cooling of the syngas which is in a phase of completion of the catalysis process, to ensure that the PH remains between the values of 6 and 7 throughout the process, any condensed high-boiling hydrocarbons being separated from the water by means of centrifugal separators and sent back to the start of the cycle, while, subsequently, the gas passes into an activated carbon filtration column to lose moisture, as well as activated carbon, the fourth section being equipped with a filtering system pushed to eliminate any formation of any pollutants present.

26. The pyrolysis plant of claim 7, wherein, in the fifth final section, in the event of an emergency, the syngas produced, after washing, is sent to an emergency torch, the induction generators are switched off automatically and the pyrolysis chamber and the stilling chamber are washed with nitrogen gas, the fifth safety section also including an emergency connection system equipped with appropriate valves designed to convey gas to the emergency torch of the pyrolysis chamber in case of failure, the fifth section also comprising a plant for the production of nitrogen by separation and the relative nitrogen storage tank.

27. A method for the treatment of solid and liquid waste, carried out by means of the plant of claim 1, the method providing for a pyrolysis treatment, of the solid and liquid waste, from which a synthesis gas, syngas, and an inert residue are obtained, the method comprising the steps of subjecting the pyrolysis products to fractional distillation and sending the bituminous residues, tar, of the fractional distillation to a new pyrolysis cycle, the solid waste including plastic materials and biomasses and being loaded directly into the pyrolysis chamber in which they undergo the pyrolysis treatment, the liquid waste comprising exhausted oils and fats which are inserted into the pyrolysis chamber after mixing with the bituminous residues, tar, coming from the fractional distillation of pyrolysis products.

28. A method for the disposal of waste consisting of plastic materials or biomass, and of all organic materials containing carbon in their molecules, carried out by means of the plant of claim 7, the method being also based on the principle that, when a molecule is introduced into an electric field, it orients itself according to its dipole and, if the electric field is repeatedly inverted, the molecule is forced to reposition itself at each inversion of the field and this causes a heating of the molecules the more efficient the closer the resonance frequency of the molecule is, but heating also occurs even when the frequencies are different from those of resonance, this method being initially based on the heating of the molecules within an electric field, up to their splitting with the formation of a synthesis gas, syngas, mainly composed of COCO.sub.2H.sub.2O.sub.2, while, subsequently, the cylinder acts as a directional antenna and, due to the effect of the induced electromagnetic field, the molecular disorder generated by the temperature undergoes an energetic contribution made by the radio frequency waves and the components of the syngas ionize strongly, interact with the superheated steam and create new ordered structures that are addressed by the PLC control of the radio frequency originating mainly CH.sub.4.

Description

[0024] The invention will now be described, by way of non-limiting example, according to a preferred embodiment and with reference to the attached FIG. 1, which shows the functional diagram of the pyrolysis system.

[0025] With reference to FIG. 1, (1) designates a pyrolysis plant, according to a first embodiment of the invention, heated with high frequency currents. This pyrolysis plant (1) includes: [0026] a first section (100), in which the pyrolysis of the waste materials takes place, the synthesis gas (syngas) is produced and the residual ashes of the treatment are discharged; [0027] a second section (200), in which the lighter fraction of said ash (coal dust or carbon black) which is transported by the syngas, is separated from said syngas; [0028] a third section (300), in which the fractional distillation of the pyrolysis products takes place, obtaining high-boiling hydrocarbons or bituminous residue (tar); [0029] a fourth section (400), in which the bituminous residue of said fractional distillation is recycled, for further treatment; and [0030] a fifth final emergency section (not shown): this final section will include, in addition to the safety pumps that will automatically intervene in the event of a system failure, all safety systems.

[0031] This first section (100) comprises a cylinder (2), or pyrolysis chamber, rotating around its own axis, externally provided with insulation, for example in ceramic fiber. An Archimedes screw finning (3) with a surface hardened by nitriding is welded into the cylinder.

[0032] The cylinder (2) is set in rotation by a first motor-reduction unit (4) and is internally heated by heating means (5), in such a way as to bring the solid mass to be pyrolyzed at a temperature of 680-750? C.

[0033] According to a preferred embodiment, the internal diameter of the pyrolysis chamber (2) will preferably be between 650 and 950 mm, while the length will preferably be between 6000 mm and 8000 mm, with a rotation at a speed for example between 1 and 3 revolutions per minute. Furthermore, the heating means (5) comprise two induction generators (6) at a radiofrequency variable between 1.5 kHz and 2.5 kHz and with a power from 80 to 120 kW each, each of which is connected to a coil (7), inside which the pyrolysis cylinder (2) rotates slowly. The two coils transmit the high frequency induced current created by the two generators in such a way that the cylinder (2) becomes the seat of eddy currents which heat it due to the Joule effect.

[0034] The temperature control is carried out by means of two laser probes (not shown) placed at the entrance and in the middle of the pyrolysis chamber (2). The two control points each consist of three sequential survey points.

[0035] The loading of the cylinder (2) takes place, at the first end (2a) of the cylinder (2), by means of a hopper (8) which feeds an auger (9) rotated by a second motor-reduction unit (10).

[0036] The material is loaded at the entrance to the pyrolysis chamber(2). If the waste to be treated is solid, it is first shredded into pieces with a size of about 1 cm and loaded by means of the screw (9) with a compression ratio preferably from 1:150 to 1:250 and with adjustable speed. If, on the other hand, the waste is liquid, it is loaded into the recycling section (400), as better specified below. The material loaded into the hopper (8) and inserted under pressure from the screw conveyor (9), arrives inside the cylinder (2) whose rotation, combined with the Archimedes screw (3), pushes it towards the second end (2b) of the cylinder (2).

[0037] In the path along the cylinder (2), at a temperature of 680-750? C., the solid waste, mainly consisting of plastic materials such as polyethylene, polypropylene, ABS, PET, polystyrene, polyurethane or biomass (wood, sewage sludge, straw rice, etc.), undergoes pyrolysis producing solid and gaseous compounds. The gaseous fraction, called syngas, includes a mixture of H.sub.2, CO, CO.sub.2CH.sub.4 (volatile fraction at room temperature) and carries high-boiling hydrocarbons, oxygenated products of various molecular weight in the form of vapor and carbon dust (carbon black), while the solid one includes extremely small amounts of residual ash.

[0038] Through an opening (11), the syngas enters a stilling chamber (12), while the residual ashes are discharged, through a duct (13), into a container (14).

[0039] The second section (200) comprises said stilling chamber (12) from which the syngas is conveyed, through a first duct (15) and a second duct (16), towards a first cyclone (17) and, respectively, a second cyclone (18). Inside said cyclones (17) and (18), the syngas is treated in such a way as to complete the separation from the coal dust (carbon black) it carried, said dust being discharged through a lower opening (17a, 18a) of the first and second cyclone (17, 18), while from the upper part (17b, 18b) the syngas thus purified from the carbon black is released.

[0040] The third section (300), in which the fractional separation of the pyrolysis products takes place, includes a fractional distillation column (19) composed of various superimposed elements equipped with condensation plates and cooling coil with regulation of the amount of water necessary for maintaining each module at the condensation temperature of the high-boiling mixtures which thus leave the syngas. All condensed high boilers are conveyed to the bottom of the column.

[0041] The syngas coming from the separator cyclones (17) and (18) enters the lower part of the fractional distillation column (19) through the ducts (20) and (21). In column (19) the volatile fraction of syngas separates from the high-boiling hydrocarbons, which form said bituminous residue (tar), exits from the upper outlet (22), while said high-boiling hydrocarbons come out from the lower outlet (23). The syngas is conveyed to a blower (not shown) which creates a slight depression in the pyrolysis chamber (2) and sends the syngas towards the basic and acid washing columns (not shown).

[0042] Through a conduit (24), which enters the upper part of the column (19), cooling water is passed, said inlet being controlled by a valve (25) and an electronic liter-counter (not shown). The water then passes through a coil (26) and exits, in the form of superheated steam, from a conduit (27).

[0043] In the fourth section (400) there is the recirculation of the high boiling hydrocarbons exiting, through the duct (23), from the lower part of the fractional distillation column (19), and of the coal dust (carbon black) extracted from the separator cyclones (17) and (18) placed at the exit of the calm chamber (12).

[0044] The fourth section (400) comprises a pump (28) which injects the high-boiling hydrocarbons into a turbo-mixer (29), operated by a third motor-reducer unit (30), the flow of the high-boiling hydrocarbons being regulated by a valve (31).

[0045] Carbon black coming from the cyclones (17) and (18) is introduced into the turbo-mixer (29) through a duct (32), the flow of carbon black being regulated by a valve (33).

[0046] Through a duct (34), liquid waste (vegetable oils and exhausted fats) are also inserted into the turbo-mixer (29), the liquid waste being inserted into a hopper (35) and their flow being regulated by a valve (36).

[0047] In the turbo-mixer (29) an emulsion is produced which, passing through a duct (37), reaches a pump (38) which inserts it into the pyrolysis chamber (2) through a duct (39). Through a duct (40), the superheated steam exiting the fractional distillation column (19) is introduced into the pyrolysis chamber (2) through the duct (27), the steam flow being regulated by a valve (41).

[0048] The turbo-mixer (29) is capable of intimately mixing the carbonaceous product coming out of the separator cyclones and the tar extracted at the base of the fractional distillation column (19). This mixing is reintroduced to the inlet of the pyrolysis chamber together with the superheated steam coming from the coils of the fractionated separation column. The amount of steam varies between 10% and 15% by weight of the waste loaded into the pyrolyzer inlet. This variation is attributable to the nature of the waste treated. This mixing becomes very efficient with the addition of exhausted vegetable oil, inserted in the hopper (35), coming from separate collection, as it has excellent dissolving properties of hydrocarbons, even at high concentrations.

[0049] The percentage of oxygen present in the pyrolysis chamber is continuously monitored and recorded by an analytical instrument type SYN 100 capable of also verifying the percentage of CO, CO.sub.2, H.sub.2 and CH.sub.4 in the syngas produced. To avoid both syngas leaks and oxygen infiltrations into the pyrolysis chamber, the solid waste is fed with the auger (9) at high compaction pressure and preheated to a suitable temperature (depending on the type of waste) to allow formation of a plug such as to guarantee the tightness of the system to the entry of air and therefore of oxygen into the pyrolysis chamber (2). A rotary valve is inserted between the loading hopper and the auger to prevent the infiltration of air and therefore of oxygen harmful to the pyrolysis process.

[0050] The pyrolysis chamber (2) is kept in a slight depression by the blower which sends the syngas towards the basic and acid washing columns, this depression being equal to about 0.7 mbar less than the external pressure.

[0051] In the event of an emergency, the syngas produced, after washing, is started with an emergency torch, the induction generators are switched off and the pyrolysis chamber is washed with nitrogen gas.

[0052] According to a further preferred embodiment, the plant of the invention substantially comprises: [0053] a waste feeding system (not shown); [0054] a first section (100) operatively connected to the waste feeding system and consisting of a concentric bimetallic cylinder (2) equipped with an Archimedes screw (3), externally insulated and slowly rotating around its own axis; [0055] the cylinder (2) ends in a second section (200) in which the thermochemical reactions are completed, and the lighter fraction of the reaction is separated from the ashes and transported by the syngas in a third section (300) in which the cooling occurs, as well as the separation of the syngas from the high boiling products of pyrolysis and from the bituminous residue as well as from the residual carbon; [0056] a fourth washing and cleaning section (400) in which the syngas enters, is washed and cleaned, and then is sent for use; and [0057] a fifth final emergency section (not shown), this final section including, in addition to the safety pumps that will automatically intervene in the event of a system failure, all safety systems.

[0058] In particular, according to the operation of this system, the crushed solid material contained in a silos is sent to the loading section (8) equipped with a rotary valve and by means of an auger (9) rotated by a gearmotor unit, the material is pressed and sent into the cylinder together with a small amount of water which is injected by means of a pump which will inject liquid waste into the first section as required.

[0059] The material reaches the inside of the cylinder (2) equipped in the initial part with a scraping system designed to prevent the formation of lumps. The rotation of the cylinder (2), carried out by means of a gearmotor group, pushes the material towards the opposite side of the chamber, thanks to the Archimedes screw (3) contained inside, and, during the path (300 mm each revolution of the cylinder), all the organic part is transformed into syngas leaving the inert ashes and any metals contained in the fed waste on the bottom of the cylinder (2) which, transported by the Archimedes screw (3), will reach the end of the cylinder (2) and will fall to the bottom of the second section (200).

[0060] The first section (100) comprises a reactor heated by two or more generators (6) of induced currents of adequate power and with a frequency between 1.5 and 5 KHz so that the cylinder becomes the seat of eddy currents which heat it by effect Joule and will bring the temperatures inside the reactor between 650 and 750? C. at which the pyrolysis process takes place.

[0061] The generators (6) are each connected to a coil (7) inside which the cylinder (2) rotates with a speed determined by the PLC and calculated by the PLC according to the transformation times of the individual matrices introduced.

[0062] According to this preferred embodiment, the cylinder (2) will have a diameter between 1200 and 1500 mm and a length between 9 and 12 m, it will be equipped with a system controlled by a gear motor suitable for its rotation as well as a system suitable for absorption of expansion due to temperatures.

[0063] The cylinder (2), at its ends, will be insulated with packing housed in a groove and kept under pressure by a series of springs and will also have a second nitrogen gas safety insulation system.

[0064] Inside the cylinder (2) there is a continuous temperature control by means of thermocouples and laser probes as well as a control of the internal pressures which, by means of a system of vacuum pumps, maintains the cylinder (2) and the final chamber (12) calm at a slight depression (about 0.7 mbar) with respect to the external atmospheric pressure, in order to prevent any risk of explosion.

[0065] The cylinder (2) and the heating (5) and movement and control systems are placed inside a Faraday cage (not shown) to isolate the outside from internal induced currents.

[0066] The syngas from the cylinder (2) is sent to the second section (200) consisting of a stilling chamber (12) where the thermochemical reactions induced by the radiomagnetic waves take place and the syngas and the lighter fractions are separated from the ashes.

[0067] The calm or ionic copulation chamber (12) is equipped with a system of augers for the extraction of the ashes. The PLC-controlled augers remain constantly full of ash which acts as a cap to prevent the escape of gases and the entry of external air; in the final part they will in any case be equipped with a one-way safety valve.

[0068] The syngas is then conveyed to a third cooling and distillation section (300) to be separated from the condensable part and the solid part by means of a distillation column (19) and a centrifugal separator (17, 18). This section (300) will also be equipped with a refrigeration plant or an ORC system for recovering and transforming heat into energy. The centrifugal separator (17, 18) will divide the condensed and solid products from the cooling water, and then send the condensed and divided products at the beginning of the cycle for a second distillation; or, the separate products will be stored for their industrial use.

[0069] The syngas cooled below 80? C. will be sent to a fourth washing section (400) which, by means of two cooling towers (not shown) containing a mixture of water, weakly acidic the first one and weakly basic the second one, in addition to a further cooling of the syngas which is in a phase of completion of the catalysis process, will ensure that the PH remains between the values of 6 and 7 throughout the process. Any condensed high-boiling hydrocarbons will be separated from the water by means of centrifugal separators and sent back to the start of the cycle. Subsequently, this gas passes into an activated carbon filtration column to lose humidity; in addition to the activated carbon, this section (400) will be equipped with a filtering system pushed to eliminate any formation of any pollutants present.

[0070] This gas will then be pushed by means of pumps towards use.

[0071] As regards the fifth final emergency section including, in addition to the safety pumps that will automatically intervene in the event of a system failure, all safety systems, in case of emergency the syngas produced, after washing, is sent to a emergency; the induction generators (6) are automatically switched off and the pyrolysis chamber (100) and the stilling chamber (12) are washed with a nitrogen gas.

[0072] This safety section also includes an emergency connection system equipped with appropriate valves suitable for conveying the gas from the pyrolysis chamber (100) to the emergency torch in the event of a fault.

[0073] The fifth final section also includes a plant for the production of nitrogen by separation and the relative nitrogen reserve tank.

[0074] The invention has been described, for illustrative and non-limiting purposes, according to a preferred embodiment. The skilled technician in the field will be able to find numerous variants, all falling within the scope of protection of the attached claims.