PLASTIC MATERIALS OR BIOMASSES

The present invention relates to a method and a plant for the disposal of solid waste , consisting of plastic or biomass materials , and liquids , particularly consisting of vegetable oils and exhausted fats , as well as of all organic materials which contain carbon in their molecules .

Waste disposal is a serious problem, as it is increasingly di f ficult to find areas for landfill , and incineration has a high cost and, i f not done correctly, can lead to environmental pollution .

Treatment plants , known as waste-to-energy plants , have established themselves , which use plastic materials as fuel to produce heat and also biomass treatment plants which, through fermentation, produce fuel gas .

Document WO-A1-2016/ 006010 describes an installation and a method according to the preamble of the independent claims .

In a first preferred embodiment , the present invention proposes a new procedure for the disposal of plastic materials, biomass and vegetable oils and exhausted fats, which makes it possible to obtain fuel gas by means of a pyrolysis treatment.

The present invention therefore proposes a method and systems for implementing said method as claimed in the respective independent claims.

The method essentially consists in subjecting the solid and liquid waste to be disposed of to a pyrolysis treatment that allows the extraction of fuel synthesis gas (syngas) , obtaining an inert residue that does not cause problems for landfill disposal.

In this embodiment, the plant substantially comprises :

• a first section in which the pyrolysis of waste materials takes place and synthesis gas (syngas) and residual ash are produced;

• a second section in which the lighter fraction of said ash, i.e. the coal dust or carbon black which is transported by the syngas, is separated from said syngas ;

• a third section in which the fractional distillation of the pyrolysis products takes place, obtaining high-boiling hydrocarbons, i.e. a bituminous residue

(tar) ; a fourth section in which the bituminous residue of said fractional distillation is recycled, for further treatment , said bituminous residue being able to be mixed with said liquid waste ; and

• a fi fth final emergency section, which will include , in addition to the safety pumps that will automatically intervene in the event of a system failure , all the safety systems .

The pyrolysis chamber basical ly consists of a special steel tube heated and equipped with a mechani zed system for the movement and controlled advancement of the solid mass to be subj ected to the pyrolysis treatment . The tube is externally insulated with ceramic fabric and, by means of a motor-reducer unit , is made to rotate slowly around its own axis .

A feature of the system is that it is energetically sel f-suf ficient , as it uses part of the fuel gas produced to power an internal combustion engine that drives an alternator that supplies the electricity used to heat the pyrolysis chamber and to operate all necessary devices to the operation of the plant .

The use of the method and the plant according to the invention ultimately allows the trans formation of solid and liquid waste into a combustible gas and inert residues . Part of the combustible gas is used to produce the energy necessary for the operation of the entire plant , while the residual inert fraction, with a volume much lower than that of the initial mass of the waste , can be disposed of in landfills without particular problems , both for reduced quantity of said ashes , both because they are not polluting .

In a second preferred embodiment , the present invention relates to a method and an industrial plant for the production of methane gas from materials containing organic carbon .

The plant and the method are able to gasi fy all organic materials essentially creating a new type o f slow wet pyrolysis in an electromagnetic field and without any emissions into the atmosphere .

Pyrolysis is a process of thermochemical decomposition of the organic substance without the addition of external oxygen which occurs solely due to the ef fect of temperature .

The operation of the plant and method of this embodiment is based on the principle that , when a molecule is placed in an electric field, it orients itsel f according to its dipole and, i f the electric field is repeatedly reversed, the molecule is forced to reposition itsel f to each inversion of the field and this causes a heating of the molecules which is all the more ef ficient the closer the resonance frequency of the molecule is , but the heating still takes place even when the frequencies are di f ferent from the resonance ones .

Also in this embodiment , the plant is made up of five sections and is initially based, in the first sector, on the heating of the molecules within an electric field, until their splitting with the formation of a synthesis gas ( syngas ) mainly composed of CO-CO ₂ -H ₂ - O ₂ ; subsequently, in the second section, the cylinder of the first section acts as a directional antenna due to the ef fect of the induced electromagnetic field, and the molecular disorder generated by the temperature undergoes an energetic contribution made by radiofrequency waves and the syngas components ioni ze strongly, interact with the superheated steam and create new ordered structures which are addressed by the PLC control of the radio frequency originating mainly CH ₄ .

The plant is contained in a Faraday cage that isolates it from the outside .

The main feature of the plant , in addition to having no emission into the atmosphere , consists in that it is energetically sel f-suf ficient as it uses a part of the gas produced to power an internal combustion engine or a turbine which, by activating an alternator, supplies the electricity used for to heat the pyrolysis chamber and to activate all devices necessary for the operation of the system.

The invention will now be described, by way of nonlimiting example, according to a preferred embodiment and with reference to the attached Fig. 1, which shows the functional diagram of the pyrolysis system.

With reference to Ffig. 1, (1) designates a pyrolysis plant, according to a first embodiment of the invention, heated with high frequency currents. This pyrolysis plant (1) includes:

• 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;

• 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;

• a third section (300) , in which the fractional distillation of the pyrolysis products takes place, obtaining high-boiling hydrocarbons or bituminous residue (tar) ;

• a fourth section (400) , in which the bituminous residue of said fractional distillation is recycled, for further treatment; and 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. 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 .

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 a 750 °C.

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.

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 .

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 motorreduction unit (10) .

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) .

In the path along the cylinder (2) , at a temperature of 680 a 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 H2, CO, CO2 CH4 (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.

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) .

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.

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.

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) .

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 litercounter (not shown) . The water then passes through a coil (26) and exits, in the form of superheated steam, from a conduit (27 ) . 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) .

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 ) .

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) .

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

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 ) .

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 o f 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 ef ficient 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 .

The percentage of oxygen present in the pyrolysis chamber is continuously monitored and recorded by an analytical instrument type SYN 100 capable of also veri fying the percentage of CO, CO2 , H2 and CH4 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 .

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 .

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

According to a further preferred embodiment , the plant of the invention substantially comprises :

- a waste feeding system (not shown) ;

- 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 ;

- 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; a fourth washing and cleaning section (400) in which the syngas enters, is washed and cleaned, and then is sent for use; and

- 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.

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.

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) .

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.

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 .

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.

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.

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.

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 .

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.

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 .

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 centri fugal separator ( 17 , 18 ) . This section ( 300 ) will also be equipped with a refrigeration plant or an ORC system for recovering and trans forming heat into energy . The centri fugal 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 .

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 centri fugal separators and sent back to the start o f 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 .

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

As regards the fi fth 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 of f and the pyrolysis chamber ( 100 ) and the stilling chamber ( 12 ) are washed with a nitrogen gas .

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 .

The fi fth final section also includes a plant for the production of nitrogen by separation and the relative nitrogen reserve tank .

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 .