PLANT FOR RECYCLING LIQUID PRODUCTION RESIDUES WITH CONVERSION THEREOF TO THERMAL ENERGY

Abstract

 A plant (1) for recycling liquid production residues (A) with conversion thereof to thermal energy, which comprises: a storage unit (2) configured to contain a biomass (B) of plant origin shredded into small fragments; a tank (3) configured to contain a processing residue in the liquid state (A); a first dryer (4) configured for the removal of water (W) from preset amounts of biomass fragments (B) of plant origin, the first dryer (4) being excludable if the biomass (B) has a moisture content lower than a preset threshold value; a mixer (5) configured to impregnate dried biomass fragments of plant origin (B1) with the processing residue in the liquid state (A) according to a preset mutual dosage; a second dryer (6) configured to remove volatile substances (E) from biomass fragments impregnated with the processing residue in the liquid state (D); an apparatus (7), of a type chosen from a gasifier and a pyrolysis unit, configured for the conversion of dried biomass fragments impregnated with the processing residue in the liquid state (D1) into fuels of a type chosen from gaseous (G), liquid and solid; a combustor (8) configured for complete thermal degradation of previously obtained gaseous fuels (G) and for the generation of thermal energy (H).

Description

[0001] The present invention relates to a plant for recycling liquid production residues that converts them into thermal energy.

[0002] Every industrial activity entails the generation of a preset amount of residues (and/or waste) that must be disposed of.

[0003] In order to dispose of industrial residues, companies often have to bear significant costs due to the need to resort to disposal facilities that have very high operating costs.

[0004] Some types of residue can be subject to direct recycling (reintroduction into the production cycle), while others require waste-to-energy processes, i.e., their use as fuel within a specific incinerator that converts the heat generated by the combustion of the residues into thermal energy that can be used for numerous purposes.

[0005] Many industrial residues are directly combustible, while in others combustion is hindered by the formation of inert substances that interrupt the process and impose numerous and complex cleanup operations.

[0006] The present description relates to production residues in the liquid state predominantly constituted by carbon (in a percentage comprised between 45% and 65%, preferably having values close to 54%-56%) and furthermore comprising oxygen (in a percentage comprised between 30% and 50%, preferably having values close to 38%-39%), hydrogen (in a percentage comprised between 3% and 10%, preferably having values close to 6%-6.5%), nitrogen (in a comprised percentage lower than 0.1%), and any other elements in varying proportions (regarding the fraction missing to reach 100%).

[0007] An analysis of the liquid residue that is the subject matter of the present description found that the liquid has a high heating value (the lower heating value is comprised between 20,000 kJ/kg and 30,000 kJ/kg; the value found on a specific sample was approximately 25,500 kJ/kg) and a low ash content (as an indication, between 0.03% and 3%; the value found on a specific sample was approximately 0.3%).

[0008] Through direct combustion, which provides for pulverizing and/or atomizing the residual liquid in a combustion chamber, the rapid formation of a sticky foam was observed; said foam solidified after cooling, resulting in the occlusion of the dispensing nozzles and the coating of the entire surface of the combustion chamber, making it unusable.

[0009] The phenomenon is also reduced by diluting the liquid residues with specific solvents (such as methanol, for example), but still takes the combustion chamber out of service (albeit after longer times).

[0010] Such problems, in the background art, therefore make it impossible to use a liquid processing residue of the type described, for its conversion into thermal energy through thermal splitting processes such as gasification, pyrolysis and the like.

[0011] The aim of the present invention is to solve the above-described problems by providing a plant for recycling liquid production residues with conversion thereof to thermal energy that can operate, even continuously, for long periods.

[0012] Within this aim, an object of the invention is to provide a plant for recycling production residues with conversion thereof to thermal energy that is suitable for processing residues comprising carbon (in a percentage comprised between 45% and 65%, preferably having values close to 54%-56%), oxygen (in a percentage comprised between 30% and 50%, preferably having values close to 38%-39%), hydrogen (in a percentage comprised between 3% and 10%, preferably having values close to 6%-6.5%), nitrogen (in a comprised percentage less than 0.1%) and any other elements in varying proportions (relative to the portion missing to reach 100%) rendered liquid by at least one respective solvent.

[0013] Another object of the invention is to provide a plant for recycling liquid production residues with conversion thereof to thermal energy which complies with current regulatory requirements.

[0014] Another object of the invention is to provide a plant for recycling liquid production residues with conversion thereof to thermal energy having high conversion efficiency.

[0015] Another object of the invention is to provide a plant for recycling liquid production residues with conversion thereof to thermal energy having low operating costs.

[0016] A further object of the present invention is to provide a plant for recycling liquid production residues with conversion thereof to thermal energy that has low costs and is relatively simple to provide in practice and of assured application.

[0017] This aim and these and other objects that will become better apparent hereinafter are achieved by a plant for recycling liquid production residues with conversion thereof to thermal energy, characterized in that it comprises:

• a storage unit configured to contain a biomass of plant origin shredded into small fragments,
• a tank configured to contain a processing residue in the liquid state,
• a first dryer configured for the removal of water from preset amounts of biomass fragments of plant origin, said first dryer being excludable if said biomass has a moisture content lower than a preset threshold value,
• a mixer configured to impregnate dried biomass fragments of plant origin with said processing residue in the liquid state according to a preset mutual dosage,
• a second dryer configured to remove volatile substances from biomass fragments impregnated with said processing residue in the liquid state;
• an apparatus, of a type chosen from a gasifier and a pyrolysis unit, configured for the conversion of dried biomass fragments impregnated with said processing residue in the liquid state into fuels of a type chosen from gaseous, liquid and solid,
• a combustor configured for complete thermal degradation of previously obtained gaseous fuels and for the generation of thermal energy.

[0018] This aim and this object are also achieved by means of a method for recycling liquid production residues with conversion thereof into thermal energy, characterized in that it comprises the steps of:

• drying a preset amount of biomass fragments of plant origin, extracting water, producing dried biomass fragments of plant origin,
• impregnating said dried biomass fragments of plant origin with production residues in the liquid state according to a preset mutual dosage, producing biomass fragments impregnated with production residues in the liquid state,
• drying said biomass fragments impregnated with production residues in the liquid state, extracting specific volatile substances and producing dried biomass fragments impregnated with liquid residues,
• processing, with a method chosen between gasification and pyrolysis, said dried biomass fragments impregnated with liquid residues, generating fuels of a type chosen from gaseous, liquid and solid,
• subjecting to complete thermal degradation said gaseous fuels, generating thermal energy.

[0019] Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the plant for recycling liquid production residues with conversion thereof to thermal energy, illustrated by way of non-limiting example in the accompanying drawing, wherein:
Figure 1 is a block diagram of the plant according to the invention.

[0020] With reference to the figure, the reference numeral 1 generally designates a plant for recycling liquid production residues A with conversion thereof to thermal energy.

[0021] The plant 1 according to the invention comprises a storage unit 2 configured to contain a biomass 3 of plant origin shredded into small fragments.

[0022] Merely by way of non-limiting example, said storage unit 2 can be constituted by a biomass storage pit 3 made of concrete (preferably vibrated reinforced concrete). A possible pilot-type plant 1 may comprise an underground storage pit with the following dimensions: length 4.0 m, width 7.0 m, and height 4.0, defining a total capacity of approximately 60 m³ (which corresponds to about 24 tons of biomass fragments 3).

[0023] The plant 1 furthermore comprises a tank 3 configured to contain the processing residue in the liquid state A.

[0024] Moreover, the plant 1 according to the invention comprises a first dryer 4 configured to remove water from preset amounts of biomass fragments 3 of plant origin.

[0025] The biomass B can be extracted from the storage unit 2, for example by means of a dosage unit that is adapted to adjust the correct amount to be transferred to the first dryer 4, which reduces/stabilizes the relative humidity thereof. The installation of the first dryer 4 is provided as a precaution (for this reason it can be excluded from the plant 1 if the biomass B has a relative humidity value lower than a preset threshold value), to avoid malfunctions of the plant 1 due to excessive relative humidity of the biomass B.

[0026] The first dryer 4 may be of the "static" type, having a cylindrical shape, with a diameter of approximately 3.2 m and a height of approximately 4 m. In this case it is externally insulated to limit heat loss.

[0027] By way of non-limiting example, it is specified that the material present inside it can be moved by means of a central rotating spool, adapted to move at low speed on the fixed bottom. Drying occurs by blowing hot air (about 75/80 °C) from the bottom; said hot air is drawn into the upper central part to be sent to a dust filtering unit (provided for example by means of bag filters). Hereinafter it will be explained that the thermal energy for the production of the hot air needed by the first dryer 4 can be recovered from the flue gas C of the plant 1 through suitable air/water exchange units. The dried biomass B is extracted from the lower part (hot region) of the first dryer 4; as regards a pilot plant 1, illustrated merely by way of non-limiting example, a flow rate of about 350 kg/hour can be expected.

[0028] The plant 1 according to the invention furthermore comprises a mixer 5 configured for impregnating the dried plant-derived biomass fragments B1 with the processing residue in the liquid state A according to a preset mutual dosage.

[0029] The mixer 5 is provided similarly to the first dryer 4, but with the internal installation of suitable sprayers to achieve mixing of the processing residue in the liquid state A with the dried biomass B1. The installed sprayers should allow to obtain a flow rate adjustment and nozzle cleaning during normal operation. The dried biomass B1 is introduced at the upper part of the mixer 5. Following impregnation, a dried biomass B impregnated with liquid residue A is generated in the mixer, is designated hereinafter as impregnated biomass D, and can be extracted from the mixer 5 from its lower part.

[0030] The plant 1 may advantageously comprise, moreover, a second dryer 6 configured for the removal of volatile substances E from the impregnated biomass fragments D, so as to dispense, in output, impregnated and dried biomass fragments D1.

[0031] Downstream of the second dryer 6 an apparatus 7 is provided, of a type chosen from a gasifier and a pyrolyzer, configured to convert the dried impregnated biomass fragments D1 into fuels of a type chosen from gaseous G, liquid and solid.

[0032] A gasifier is a component adapted for performing a gasification process.

[0033] Gasification is a process by means of which a solid or liquid fuel can be converted into a gaseous mixture that can be used as a fuel or for chemical syntheses. The fuel is placed in contact with less oxygen than necessary for stoichiometric combustion, and at high temperatures. The main product is syngas G, a gaseous mixture rich in hydrogen and carbon monoxide.

[0034] The amounts of CO₂ released into the atmosphere as a result of the above-mentioned combustion are exactly the same as those stored by the plant biomass in the course of its life through photosynthesis. This is therefore a zero-emission renewable energy source (if only plant biomass is used as raw material).

[0035] In the case being considered, the gasifier 7 ensures that it has an extremely low amount of waste, constituted by ash F (which in any case causes a negligible environmental impact).

[0036] A pyrolyzer is a component adapted for implementing a pyrolysis process.

[0037] Pyrolysis is instead a heat treatment process that can be used for the energy conversion of various organic materials, as long as they have a low water content (< 15%). The process, also termed dry distillation, consists of nonoxidative thermal decomposition, i.e., without oxygen input from outside except for that which may already be present in the biomass. Decomposition takes place in the 400-800°C temperature range and the molecules of organic substances are transformed into simpler elements.

[0038] The reaction products are constituted by: a carbon-based solid fraction equal to approximately 20 - 30% by weight of the initial material, having a good heating value (8000 kcal/kg), which can be used as a fuel; a liquid fraction equal to approximately 50-60% by weight that can be considered as a bio-oil, containing paraffins, isoparaffins, olefins, aromatic hydrocarbons and numerous oxygenated, chlorinated and sulfurated substances and having an energy content of approximately 22-23 MJ/kg on a dry basis and 16 - 18 MJ/kg with 20% water; a gaseous fraction constituting about 15 - 30% by weight, also termed pyrolysis gas, mainly composed of hydrogen, carbon monoxide, carbon dioxide, and light hydrocarbons; this fraction has a heating value of about 15-22 MJ/kg and can be used for various purposes such as drying the raw material or generating electric power, or can be stored and sold to third parties.

[0039] Downstream of the apparatus 7 (be it a gasifier or a pyrolysis unit) there is a combustor 8 configured for the complete thermal degradation of the gaseous fuels G previously obtained and dispensed by the apparatus 7 and the generation of thermal energy W.

[0040] The plant 1 according to the invention may furthermore comprise a duct for conveying the volatile substances E into the combustor 8 with consequent mixing thereof with the gaseous fuels G and thermal degradation of the G+E mixture constituted by them.

[0041] The combustor 8, fed by the gaseous fuels G and by the volatile substances E dispensed by the second dryer 6, provides for combustion air to be supplied and adjusted automatically to achieve complete oxidation of the G+E mixture at a temperature of approximately 1,100 °C. Thermal recovery of the flue gases is carried out by means of a suitable boiler 9 with diathermic oil at 280°C which can optionally be arranged in parallel with an existing thermal energy supply network, adopting a suitable manifold to be placed on said network.

[0042] The pilot plant 1 currently under study (illustrated merely by way of non-limiting example) may have a rated power P of approximately 3,000 kW.

[0043] At the output of the diathermic oil recovery boiler 9 an apparatus is provided that is configured to recover the heat contained in the flue gas F: in this case, an air/water exchange unit is preferably used to produce hot water at approximately 80° to be sent to the mixer 5 and to the first dryer 4 (it has thus been shown that the energy supply of the components can be obtained as a by-product of the plant 1). The flue gas is discharged into the atmosphere at the temperature of approximately 140°C to avoid the forming of condensation (which should in turn be disposed of).

[0044] It is appropriate to point out that the plant 1 according to the invention can conveniently comprise lines for conveying the biomass of plant origin B, interposed between the storage 2 unit and the first dryer 4, as well as between the first dryer 4 and the mixer 5; moreover, additional lines for conveying the impregnated biomass D are provided which are interposed between the mixer 5 and the second dryer 6 and also between the second dryer 6 and the apparatus 7.

[0045] Such conveyance lines may advantageously be of a type preferably chosen from conveyor belts, screw feeders, screw feeders, gear conveyors and the like.

[0046] For example, the biomass B may be transported, by means of an extraction screw feeder arranged on the dosage unit (optionally also constituted by multiple consecutive branches variously oriented so as to follow the desired path), so that it can be fed into the upper part of the first dryer 5.

[0047] In general, the lifting/conveyance of the biomass B from the storage unit 2 (the storage pit) occurs via a series of horizontal/vertical/inclined screw feeders. By way of example, an extraction screw feeder (arranged horizontally at the bottom of the storage unit 2 and intended to extract the fragments of biomass B) may be provided; downstream of said extraction screw feeder a lifting screw feeder is provided, which is mounted vertically to lift the biomass B fragments from the bottom of the storage unit 2 (with reference to the example described earlier, said bottom would be at an indicative elevation of approximately -4.5 m) to the required height (for example, an elevation of 4.5 m). At this point, downstream of the lifting screw feeder an upper screw feeder is provided, which is mounted horizontally and above the dosage unit to receive the biomass fragments B, lifted by the lifting screw feeder, and convey them into the dosage unit.

[0048] With reference to an embodiment of unquestionable interest in application and in practice, the dosage unit may be loaded through two loading ports to have a uniform distribution on specific conveyance rakes. The expected flow rate for the apparatuses intended for loading the dosage unit in the pilot plant 1 already partially shown above may be on the order of approximately 20 m³/hour.

[0049] It is specified that the plant 1 according to the invention may advantageously comprise stations for filtering exhaust gases C and volatile matter E: such filtering stations are configured to block particulate matter having a particle size above a preset threshold.

[0050] In particular, it is specified that filters with a filtering capacity such as to trap dust with a particle size greater than 5 µm may be used.

[0051] Filtration of discharged gases (thus of the exhaust gases C, of the volatile substances E and, optionally, also of the steam W emitted by the first dryer 4) with fabric filters is provided in order to achieve the necessary cleanliness thereof and not have dust pollution. The filters to be used are preferably so-called "bag filters," dust removal apparatuses calibrated to trap dust with particle size values above a preset threshold value (in the case exemplified above, 5 µm). Such bag filters are provided with an automatic compressed air apparatus for their continuous cleaning with pulse and cycle time adjustment.

[0052] It is important to show that the biomass B of plant origin may efficiently be of a type preferably chosen from lignocellulosic biomass, wood chips, pellets, and the like. In particular, it is pointed out that the use of wood chips ensures optimal results in terms of efficiency of the plant 1 and efficiency in the production of thermal energy P.

[0053] As stated above, the plant 1 comprises at least one heat exchanger configured for heating, using a thermal energy chosen from that generated by the combustor 8 (thermal energy H) and that of the flue gas C delivered by the combustor 8, of a carrier fluid intended to supply a device of the type of a diathermic oil boiler 9, an electric power generator, a piece of industrial machinery, and a combination thereof.

[0054] It is specified that, with reference to a particularly interesting application of the invention, the liquid production residues A are constituted by a substance T in the solid state at room temperature, treated with a solvent S chosen from methanol, ethanol, butanol, isopropyl alcohol, esters, ketones and ethers.

[0055] Such substance T in the solid state at room temperature will comprise: carbon, in a percentage comprised between 45% and 65%, preferably having values close to 54%-56%; oxygen, in a percentage comprised between 30% and 50%, preferably having values close to 38%-39%; hydrogen, in a percentage comprised between 3% and 10%, preferably having values close to 6%-6.5%, nitrogen in a comprised percentage of less than 0.1% and any other elements in variable proportions.

[0056] Such substance T, in the case of main interest in application, may be a dark-colored solid constituted by hydrocarbons and free carbon. This substance S could be extracted from a wide variety of organic materials through a destructive distillation process.

[0057] In particular, the use of a substance S constituted by "distillation residues" or "distillation tails" is of interest.

[0058] This substance S is solid at room temperature and can be kept liquid only through the use of a solvent (for example, any of those mentioned above, among which methanol constitutes one of the most likely applicable). From a chemical standpoint, the substances S are condensation products obtained in the reaction and by thermal degradation in distillation.

[0059] The protection provided by the present invention also extends to a method for recycling liquid production residues A with conversion thereof to thermal energy P, which consists of a series of consecutive steps.

[0060] In a first step I, it is necessary to dry a preset amount of biomass fragments B of plant origin, extracting water W.

[0061] Then, during a second step II, it is necessary to impregnate said dried biomass fragments B1 with production residues in the liquid state A according to a preset mutual dosage, obtaining an impregnated biomass D.

[0062] A third step III then entails drying the impregnated biomass D, extracting specific volatile substances E, obtaining a dried impregnated biomass D1.

[0063] In a fourth step IV, the impregnated and dried biomass fragments D1 are gasified, generating fuels of a type chosen from gaseous G, liquid and solid (the last two exclusively if the apparatus 7 is constituted by a pyrolysis unit).

[0064] The gaseous fuels G and liquid and solid fuels, optionally also mixed with the volatile substances E extracted in the third step III, may be subjected, during a fifth step V, to complete gaseous thermal degradation, generating thermal energy H.

[0065] The method 1 according to the invention comprises at least one sixth step VI of heat exchange for heating at least one transfer fluid that will have a rated power P.

[0066] Depending on the requirements of the amount of residues A to be processed and on the thermal energy H that it is necessary to generate in order to have the required nominal power P available, the plant 1 according to the invention may be provided in different sizes or may be constituted by a parallel arrangement of individual plants 1 that may operate simultaneously or separately as a function of the specific requirements.

[0067] It is noted that for the present invention, numerous experimental tests have shown the undoubted practical efficiency, even on an industrial scale, if the apparatus 7 is constituted by a gasifier; if the apparatus 7 is a pyrolysis unit, tests conducted mainly on a laboratory scale have shown unquestionable efficiency (for this reason it is deemed that this version also will be implemented industrially).

[0068] It is specified that the ratio of liquid production residues A to biomass B may preferably be such that the residues constitute a fraction comprised between 20% and 70% of the impregnated biomass D, preferably between 30% and 60%, even more preferably between 35% and 45%.

[0069] Advantageously, the present invention avoids the drawbacks described earlier by providing a plant 1 for recycling liquid production residues A with conversion thereof to thermal energy H that can operate, even continuously, for long periods.

[0070] The plant 1 according to the invention, since it is not subject to accumulation of substances that inhibit the reactions intended therein, can operate for very long periods without malfunctions or failures.

[0071] Conveniently, the plant 1 according to the invention is adapted to process residues comprising carbon (in a percentage comprised between 45% and 65%, preferably having values close to 54%-56%), oxygen (in a percentage comprised between 30% and 50%, preferably having values close to 38%-39%), hydrogen (in a percentage comprised between 3% and 10%, preferably having values close to 6%-6.5%), nitrogen (in a comprised percentage lower than 0.1%), and any other elements in varying proportions (relative to the fraction missing to reach 100%) rendered liquid by means of at least one respective solvent.

[0072] Advantageously, the plant 1 according to the invention complies with current regulatory requirements.

[0073] Favorably, the plant 1 according to the invention has high conversion efficiency.

[0074] Usefully, the plant 1 according to the invention has low operating costs (in particular when the biomass B is constituted by wood chips, it has been calculated that the operating costs will be far lower than the savings due to the non-purchase of methane gas for thermal energy production and the elimination of the costs for disposal of the residues A).

[0075] Validly, the plant 1 and the method according to the invention are relatively simple to provide in practice and have low costs: these characteristics make the plant 1 and the method according to the invention innovations of assured application.

[0076] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may furthermore be replaced with other technically equivalent elements.

[0077] In the exemplary embodiments shown, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other exemplary embodiments.

[0078] In practice, the materials used, as well as the dimensions, may be any according to the requirements and the state of the art.

[0079] The disclosures in Italian Patent Application No. 102023000003249 from which this application claims priority are incorporated herein by reference.

[0080] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A plant for recycling liquid production residues (A) with conversion thereof to thermal energy, characterized in that it comprises:

- a storage unit (2) configured to contain a biomass (B) of plant origin shredded into small fragments,

- a tank (3) configured to contain a processing residue in the liquid state (A),

- a first dryer (4) configured for the removal of water (W) from preset amounts of biomass fragments (B) of plant origin, said first dryer (4) being excludable if said biomass (B) has a moisture content lower than a preset threshold value,

- a mixer (5) configured to impregnate dried biomass fragments of plant origin (B1) with said processing residue in the liquid state (A) according to a preset mutual dosage,

- a second dryer (6) configured to remove volatile substances (E) from biomass fragments impregnated with said processing residue in the liquid state (D);

- an apparatus (7), of a type chosen from a gasifier and a pyrolysis unit, configured for the conversion of dried biomass fragments impregnated with said processing residue in the liquid state (D1) into fuels of a type chosen from gaseous (G), liquid and solid,

- a combustor (8) configured for complete thermal degradation of previously obtained gaseous fuels (G) and for the generation of thermal energy (H).

2. The plant according to claim 1, characterized in that it comprises a duct for conveying said volatile substances (E) into said combustor (8) with consequent mixing thereof with said gaseous fuels (G) and thermal degradation of the mixture (G+E) constituted thereby.

3. The plant according to claim 1, characterized in that it comprises lines for conveying said biomass (B, B1) of plant origin which are interposed between said storage unit (2) and said first dryer (4), between said first dryer (4) and said mixer (5) and lines for conveying said biomass of plant origin mixed with said liquid production residues which are interposed (D, D1) between said mixer (5) and said second dryer (6) and between said second dryer (6) and said apparatus (7), said conveyance lines being of a type preferably chosen from conveyor belts, screw conveyors, auger conveyors, gear conveyors and the like.

4. The plant according to claim 1, characterized in that it comprises stations for filtering exhaust gases (C), volatile substances (E) and vapors (W), configured to block particulate matter having a particle size above a preset threshold.

5. The plant according to claim 1, characterized in that said biomass (B) of plant origin is of a type preferably chosen from lignocellulosic biomass, wood chips, pellets and the like.

6. The plant according to claim 1, characterized in that it comprises at least one heat exchanger configured for heating, using a thermal energy chosen from that generated by said combustor (8) and that of the exhaust gases (C) delivered by said combustor (8), a transfer fluid intended to feed a device (9) of the type of a diathermic oil boiler, an electric power generator, a piece of industrial machinery and a combination thereof.

7. The plant according to claim 1, characterized in that said liquid production residues (A) are constituted by a substance (T) in the solid state at room temperature, treated with a solvent (S) chosen from methanol, ethanol, butanol, isopropyl alcohol, esters, ketones and ethers, said substance in the solid state (T) at room temperature comprising carbon, in a percentage comprised between 45% and 65%, preferably having values close to 54%-56%, oxygen, in a percentage comprised between 30% and 50%, preferably having values close to 38%-39%, hydrogen, in a percentage comprised between 3% and 10%, preferably having values close to 6%-6.5%, nitrogen in a comprised percentage lower than 0.1%, and any other elements in varying proportions.

8. A method for recycling liquid production residues (A) with conversion thereof to thermal energy (H), characterized in that it comprises the steps of:

- drying a preset amount of biomass fragments (B) of plant origin, extracting water (W), producing dried biomass fragments of plant origin (B 1),

- impregnating said dried biomass fragments (B 1) of plant origin with production residues in the liquid state (A) according to a preset mutual dosage, producing biomass fragments impregnated with production residues in the liquid state (D),

- drying said biomass fragments impregnated with production residues in the liquid state (D), extracting specific volatile substances (E) and producing dried biomass fragments impregnated with liquid residues (D 1),

- processing, with a method chosen between gasification and pyrolysis, said dried biomass fragments impregnated with liquid residues (D1), generating fuels of a type chosen from gaseous (G), liquid and solid,

- subjecting to complete thermal degradation said gaseous fuels (G), generating thermal energy (H).

9. The method according to claim 8, characterized in that at said thermal degradation step said gaseous fuels (G) are mixed with said volatile substances (E) extracted in the second drying step.

10. The method according to claim 8, characterized in that it comprises at least one heat exchange step for heating at least one transfer fluid.

Drawing