METHOD AND APPARATUS FOR RAPID DRY CARBONIZATION OF ORGANIC WASTE, APPARATUS AND CATALYTIC SYSTEM ASSOCIATED TO THE METHOD

Abstract

A method for transforming waste into carbon in a reactor, said method comprising: a) drying the waste by submitting said waste to a pressure of at least 3 bar, and a temperature of at least 250° C.; b) releasing the water vapor out of the reactor, and; c) carbonizing at least partially the waste by maintaining said waste during a period of time of at least 5 minutes to a pressure of at least 3 bar, and a temperature of at least 250° C., thereby obtaining carbon; and d) optionally separating non-organic material from the obtained carbon.

Claims

1. A method for transforming waste into carbon in a reactor, said method comprising: a) drying the waste by submitting said waste to a pressure of at least 3 bar, and a temperature of at least 250° C.; b) releasing the water vapor out of the reactor, and; c) carbonizing at least partially the waste by maintaining said waste during a period of time of at least 5 minutes to a pressure of at least 3 bar, and a temperature of at least 250° C., thereby obtaining carbon; and d) optionally separating non-organic material from the obtained carbon.

2. The method according to claim 1, wherein in step a) and in step c), said pressure is, each independently, at least 4 bar, at least 5 bar, at least 6 bar, at least 7 bar, at least 8 bar, at least 9 bar, or at least 10 bar.

3. The method according to claim 1, wherein in step a) and in step c), said temperature is, each independently, at least 275° C., at least 300° C., at least 325° C., or at least 350° C.

4. The method according to claim 3, wherein in step c), said period of time is at least 7 minutes, at least 10 minutes, at least 15 minutes, or at least 20 minutes.

5. The method according to claim 1 wherein said method, after the carbonizing step c), further comprises depressurizing and cooling at a temperature below 100° C.

6. The method according to claim 1, wherein the temperature of at least 250° C. is supplied by a heating means and a catalytic system.

7. The method according to claim 6, wherein the catalytic system comprises i) at least one nanofluid aqueous solution and ii) at least one thermal conductive gas supplied into the reactor.

8. The method according to claim 7, wherein the at least one thermal conductive gas is selected from helium, hydrogen, CO.sub.2, CO, argon, ethylene, HCl, H.sub.2S, neon, and any combination thereof.

9. The method according to claim 7, wherein the at least one nanofluid aqueous solution is obtained by mixing titanium dioxide nanoparticles and sodium dodecylsulfate in water.

10. The method according to claim 7, wherein the at least one thermal conductive gas is a non-explosive mixture of hydrogen and helium, and the hydrogen is supplied into the reactor by means of a hydride powder.

11. A reactor for transforming organic material or waste into carbon according to the method of claim 1.

12. A catalytic system comprising i) at least one nanofluid aqueous solution and ii) at least one thermal conductive gas as defined in claim 8.

13. The method according to claim 1, wherein the waste is selected from municipality solid waste, hospital waste, drugs, slaughterhouse waste, sludge collected from sewage, and industrial organic waste.

14. The method according to claim 1, wherein the waste comprises non-organic material such as metal or glass.

15. The method according to claim 1, wherein at least a portion of the obtained carbon is recycled to heat the reactor.

16. The reactor according to claim 11, wherein said reactor further comprises an inlet for supplying an at least one thermal conductive gas, and an outlet for releasing the water vapor.

17. The reactor according to claim 11, wherein said reactor further comprises a heating system, a cooling system, an air-pressure system, a security valve, and one or two doors.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0033] FIG. 1 is a representation of some of the chemical constituents of organic waste.

[0034] FIG. 2 shows the internal breaking of the C—C bonds in a molecule.

[0035] FIG. 3 is a scheme representing the constituents and transformed material from waste material. The humidity is ejected as steam water while the organic matter is transformed into carbon.

[0036] FIG. 4 is a picture of a reactor configured according to the present invention and with a capacity of 3500 kg.

[0037] FIGS. 5A and 5B show the same material, pharmaceutical products, before and after carbonization.

[0038] FIGS. 6A and 6B show the same material, polyethylene bottle, before and after carbonization.

[0039] FIGS. 7A and 7B show the same material, leather, before and after carbonization.

[0040] FIGS. 8A and 8B show the same material, cabbage, before and after carbonization.

[0041] FIGS. 9A and 9B show the same material, banana, before and after carbonization.

[0042] FIGS. 10A and 10B show the same material, waste, before and after carbonization.

[0043] FIG. 11 shows the effect of temperature on the carbonization level, i.e. expressed as the percentage of generated carbon when setting the pressure to 10 bars and increasing the temperature from 150° C. to 450° C.

[0044] FIG. 12 shows the impact of pressure on the carbonization and ash formation levels, expressed as the percentage of the carbon and ash obtained when setting the temperature to 400° C. and increasing the pressure from 1 to 10 bars.

[0045] FIG. 13 shows the carbon obtained from 3.5 tons of municipal solid waste after being submitted during 15 minutes to the conditions described in Example 2.

[0046] FIG. 14 shows the steam water ejected from the reactor containing the 3.5 tons of municipal solid waste after being submitted during 15 minutes to the conditions described in Example 2.

SUMMARY OF THE INVENTION

[0047] Rapid carbonization of waste and organic material is a technology that can transform waste and organic material in general into carbon, and which technology can be used without producing any environmentally toxic emissions. The final products are carbon and water, such as notably distilled water, in addition to non-organic materials, if present in the starting material. This technology is capable of transforming waste and organic material into carbon within 5 to 35 minutes. It is environmentally friendly, and an economical method. The obtained carbon can be reused for generation of heat, for example in cement manufacturing or other metallurgic industries. This technology is also a new source of clean and hot water.

[0048] The basis of this invention relies on the combination of a first step of drying the starting material, if not yet dry, applying heat (wherein the temperature is maintained at 250 to 450° C., preferably at 350 to 450° C.), an air pressure above 3 bars, preferably above 8 bars, in a short period of time, thereby carbonizing organic material and converting it into carbon. This is possible by an effective and fast transfer of heat, which in one embodiment is achieved by means of a catalytic system that entraps and diffuses the heat into the material to be carbonized, in a highly effective manner. In another embodiment, it is achieved by means of a catalytic system that diffuses the heat into the material to be carbonized. This invention has the additional advantage that is its ability to work with the presence of both oxygen and humidity.

DETAILED DESCRIPTION OF THE INVENTION

[0049] The present invention works by combining heat, air pressure, and a rapid transfer of heat, in one embodiment by means of a catalytic system, thereby transforming organic material into carbon in a short period of time. Humidity is transformed to water vapor.

[0050] Said water vapor can then be cooled to become water, such as notably distilled water. Starting organic materials after processing become high-purity carbon, preferably in a 92% to 97% content.

[0051] The present invention is capable of carbonizing organic waste (for example municipality waste, hospital waste, expired drugs, slaughter house waste, skins and meat, sewage sludge, industrial organic waste, etc.) and can work both in the presence or absence of oxygen and in the presence or lack of moisture.

[0052] The beneficial results of this invention, include production of carbon as an energy source; production of water vapor/distilled water which can be further used; space required of use is small; processing time is fast; cost is low; and the process is environment friendly without causing any toxic emissions. In particular, the present invention is capable of dealing with most hospital waste by transforming it to carbon without the need for sterilization. The invention is also capable of processing expired drugs by transforming them to carbon without any toxic emissions. The invention is also capable to transform sewage sludge to carbon without any toxic emissions. The invention is also capable of transforming slaughter house waste to carbon without any toxic emissions.

[0053] The process according to the present invention works as follows. The chemical molecules which form the starting waste include a large number of molecules like those shown in FIG. 1. After water evaporates, the bonds holding the carbon molecules start to break as it is shown in the below FIG. 2. At the end of the required cycle, all the water is extracted from the organic material in the form of water vapor and all the remaining material transforms into coal (carbon) as it is shown in FIG. 3.

[0054] Testing has shown that after cooling the water, vapor transforms into distilled water and that the carbon produced from the above-mentioned carbonization process represents a high purity carbon (like 95% to 98%) of the dry material after water evaporation as set out in the Table below:

TABLE-US-00001 No. Sample Trial % N % C % H % S 1 Solid 1 0 97.8558 0 0 2 Solid 2 0 98.1207 0 0

[0055] After evaporating the water from the processed waste, only the dry material remains which, under the influence of heat, air pressure, and the fast transfer of heat into the waste, in one embodiment by means of a catalytic system, it transforms into carbon through the internal breaking of C—C bonds of the organic molecules. Breaking of C—C bonds is achieved in a fast, economic, clean, and efficient way according to the present invention.

[0056] The invention relies on the speed by which the heat reaches the required temperature level and the diffusing capabitlity to transfer the heat to all the components of the organic material inside the reactor.

[0057] As an example of a way to achieve this speed of heat transfer, the present invention provides a catalytic system comprising a heat trapping composition made out of graphite and prepared with the SOL-GEL technique and coating the inside walls of the reactor (this material is known for its ability to absorb high levels of heat) in addition to the use of a mixture of thermal conductive gases including helium, nanofluids, and any mixture thereof. This mixture of gases or the nanofluids, known for their high calorific conductivity after absorbing the heat kept by the materials prepared through the SOL-GEL method, disperses or vehiculates said heat inside the waste material which needs to be processed, which dispersion ensures that the heat is spread in the required speed and throughout the entire mass of the waste material.

[0058] As another example of a way to achieve this speed of heat transfer, the present invention provides a catalytic system comprising a mixture of thermal conductive gases including helium mixed with nanofluids materials. This mixture of gases mixed with nanofluid materials, known for its high calorific conductivity, disperses or vehiculates said heat inside the waste material which needs to be processed, which dispersion ensures that the heat is spread in the required speed and throughout the entire mass of the waste material.

[0059] Another important aspect is the use of high pressure inside the reactor, which needs to reach 3 bars or more, preferably 7 bars or more, more preferably 8 bars or more, which high pressure prevents combustion reactions, with the consequent undesirable formation of more ash than carbon.

Embodiments

[0060] The present invention relates to a method for transforming waste into carbon in a reactor, said method comprising:

[0061] a) drying the waste by submitting said waste to a pressure of at least 3 bar, and a temperature of at least 250° C.;

[0062] b) releasing the water vapor out of the reactor, and;

[0063] c) carbonizing at least partially the waste by maintaining said waste during a period of time of at least 5 minutes to a pressure of at least 3 bar, and a temperature of at least 250° C., thereby obtaining carbon; and

[0064] d) optionally separating non-organic material from the obtained carbon.

[0065] It is understood that the released vapor can be cooled to water. Optionally, distilled water can be obtained by cooling said released water vapor.

[0066] In one embodiment, in step a) and in step c), said pressure is, each independently, at least 4 bar, at least 5 bar, at least 6 bar, at least 7 bar, at least 8 bar, at least 9 bar, or at least 10 bar.

[0067] In one embodiment, in step a) and in step c), said temperature is, each independently, at least 275° C., at least 300° C., at least 325° C., or at least 350° C.

[0068] In one embodiment, in step c), said period of time is at least 7 minutes, at least 10 minutes, at least 15 minutes, or at least 20 minutes.

[0069] Preferably, the present invention relates to a method for transforming waste into carbon in a reactor, said method comprising:

[0070] a) drying the waste by submitting said waste to a pressure of between 8 and 10 bar, and a temperature between 350 and 450° C.;

[0071] b) releasing the water vapor out of the reactor, and;

[0072] c) carbonizing at least partially the waste by maintaining said waste during a period of time between 5 to 25 minutes to a pressure between 8 and 10 bar, and a temperature between 350 to 450° C., thereby obtaining carbon; and

[0073] d) optionally separating non-organic material from the obtained carbon.

[0074] It is understood that the released vapor can be cooled to water. Optionally, distilled water can be obtained by cooling said released water vapor.

[0075] In one embodiment, in the method according to the invention, after the carbonizing step c), the method further comprises depressurizing and cooling at a temperature below 100° C. This depressurizing and cooling step allows the safe opening of the reactor and removal of the converted carbon and optionally, if present, of the non-organic material.

[0076] In another embodiment, in the method according to the invention, after the carbonization step c), the method further comprises transfer of the carbon in a chamber, in particular a cooling chamber which is installed below the reactor. Depressurization of said chamber, at a temperature below 100° C. enables flushing the carbon. If desired, at the same time, another batch of waste may be added to the reactor through another room preferably installed above the carbonization reactor thereby replacing the carbonized waste which was transferred in said chamber. In this manner, the method according to the invention is a continuous method thereby allowing to save time and energy.

[0077] In one embodiment, in the method according to the invention, the temperature of at least 250° C. is supplied by a heating means and a catalytic system.

[0078] In one embodiment, the catalytic system comprises i) a heat trapping composition coating at least partially the inside walls of the reactor, and ii) at least one thermal conductive gas supplied into the reactor.

[0079] In one embodiment, the heat trapping composition is made from a colloidal solution comprising i) an inorganic water-based binder that resists temperatures of up to 500° C., ii) a heat trapping powder, and iii) a suitable solvent.

[0080] In one embodiment, the heat trapping powder comprises i) a carbon-based powder selected from graphite powder, carbon black powder, carbon nanotubes, carbon fibres, coke, graphene, charcoal powder, and any mixture thereof; and optionally ii) a metal powder selected from zinc, tin, iron, aluminium, tungsten, titanium, zirconium, niobium, boron, any transition metal, and any mixture thereof.

[0081] In one embodiment, the heat trapping powder has particle diameters D90 of less than 10 μm on dry sieving.

[0082] In one embodiment, the inorganic water-based binder that resists temperatures of up to 500° C. is an inorganic silicon water-based binder.

[0083] In one embodiment, the at least one thermal conductive gas is selected from helium, hydrogen, CO.sub.2, CO, argon, ethylene, HCl, H.sub.2S, neon, and any combination thereof.

[0084] In one embodiment, the at least one thermal conductive gas is a nanofluid obtained by mixing titanium dioxide nanoparticles and sodium dodecylsulfate in water.

[0085] In one embodiment, the at least one thermal conductive gas is a non-explosive mixture of hydrogen and helium, and the hydrogen is supplied into the reactor by means of a hydrogen-generating powder, preferably a hydride powder.

[0086] In one embodiment, the hydrogen-generating powder is supplied into the reactor before step b), i.e. when there is still some water or water vapor inside the reactor.

[0087] In one embodiment, a nanofluid obtained by, for example, a mixture of titanium dioxide nanoparticles, sodium dodecylsulfate and water (10 g of titanium dioxide, concentration of dodecylsodium sulfate=1 mol per liter) is used in addition to or in substitution of the thermal conductive gas.

[0088] In another embodiment, the catalytic system comprises a mixture of at least one thermal conductive gas and at least one nanofluid material (e.g. a thermal conductive nanofluids liquid). Said thermal conductive nanofluids liquid can be supplied into the reactor. An example of such nanofluid material may be a mixture of nanoparticules of tatinium dioxide mixed with sodium dodecylsulfate in aqueous solutions or with other inorganic nanoparticles.

[0089] In one embodiment, the waste is selected from municipality solid waste, hospital waste, drugs, slaughterhouse waste, sludge collected from sewage, and industrial organic waste.

[0090] In one embodiment, the waste comprises non-organic material such as metal or glass.

[0091] In one embodiment, at least a portion of the obtained carbon is recycled to heat the reactor.

[0092] The present invention further relates to a reactor for transforming organic material or waste into carbon, characterized in that at least partially the inside walls of the reactor are coated with a heat trapping composition, as defined above, made from a colloidal solution comprising i) an inorganic water-based binder that resists temperatures of up to 500° C., ii) a heat trapping powder, and iii) a suitable solvent.

[0093] In one embodiment, said reactor further comprises an inlet for supplying the at least one thermal conductive gas as defined above, and an outlet for releasing the water vapor.

[0094] In one embodiment, said reactor further comprises a heating system, a cooling system, an air-pressure system, a security valve, and one or two doors.

[0095] The present invention further relates to a colloidal solution comprising i) an inorganic water-based binder that resists temperatures of up to 500° C., ii) a heat trapping powder, and iii) a suitable solvent; wherein the heat trapping powder comprises iia) a carbon-based powder selected from graphite powder, carbon black powder, carbon nanotubes, carbon fibres, coke, graphene, charcoal powder, and any mixture thereof; and optionally iib) a metal powder selected from zinc, tin, iron, aluminium, tungsten, titanium, zirconium, niobium, boron, any transition metal, and any mixture thereof; wherein the heat trapping powder has particle diameters D90 of less than 10 μm on dry sieving; characterized in that the weight ratio of carbon-based powder of the heat trapping powder relative to the inorganic water-based binder is 0.70-1.30:1, preferably 1:1.

[0096] The present invention further relates to a heat trapping composition made from the colloidal solution defined above.

[0097] The present invention further relates to a catalytic system comprising i) the heat trapping composition as defined above, and ii) at least one thermal conductive gas as defined above.

[0098] In one embodiment, the obtained carbon of the present invention has a purity of at least 80%, preferably at least 90% (w/w), more preferably at least 92%, even more preferably at least 95%, yet even more preferably at least 98%.

[0099] The present invention further relates to the use of the colloidal solution, the heat trapping composition, the thermal conductive gas, the catalytic system, and the reactor coated with the heat trapping composition of the invention, as agents and tools for carbonization of organic waste.

[0100] Definitions

[0101] The term “carbonization” or “carbonizing” refers to the conversion of an organic molecules into carbon or a carbon-containing residue, by breaking carbon-carbon bonds.

[0102] Catalytic System

[0103] The catalytic system of the present invention consists of two main components: a heat trapping composition and at least one thermal conductive gas.

[0104] For practical reasons, the heat trapping composition takes the form of a solid layer coating at least partially, preferably most of, or entirely the inside walls of the reactor, but the invention is not limited to this specific form.

[0105] The term “coating” refers to a liquid, liquefiable, or mastic composition that, after application to a substrate in a thin layer, converts to a solid film.

[0106] The heat trapping composition absorbs the maximum heat at the internal surface of the reactor. The selection of raw materials to be used as heat trapping agentsis based on their resistivity at high temperatures, i.e. up to 500° C. in the present invention, and the potential to absorb the maximum of heat. Graphite is a material that can be used as a heat trapping agent because it supports these high temperatures and at the same time it can absorb the maximum of heat, given that it is a black body. As the person skilled in the art knows, the term “black body” refers to an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence. A black body in thermal equilibrium (that is, at a constant temperature) emits electromagnetic radiation called black-body radiation. The radiation is emitted according to Planck's law, meaning that it has a spectrum that is determined by the temperature alone, not by the body's shape or composition. A black body in thermal equilibrium has two notable properties: (1) It is an ideal emitter: at every frequency, it emits as much energy as or more energy than any other body at the same temperature. (2) It is a diffuse emitter: the energy is radiated isotropically, independent of direction. Equivalents to graphite include, without being limited to, black-coloured anodised aluminium, charcoal powder such as Japanese Bincho charcoal powder, carbon black powder, carbon nanotubes, carbon fibres, coke, graphene, any carbon composite material, or a mixture of at least two of those materials. Of interest here are the physical characteristics, such as heat transfer coefficient, thermal conductivity and heat capacity of the materials used.

[0107] Examples of suitable graphites are Graphit AF96/97 Graphitwerk Kropfmühl AG—Germany (graphite); Cond 8/96, Graphite Týn, spot, s.r.o.—Czech Republic (micronized graphite); DonaCarbo S-241, Osaka Gas Chemicals Co, Ltd—Japan (carbon fibre); Minatec 40 cm, Merck KGaA—Germany (mica coated with antimony-doped tin oxide; Raven 1000, ex. Columbian Carbon—USA (carbon black); Carbon black Powercarbon 4300F, ex. Yongfeng Chemicals—China; Lamp Black 103, ex. Degussa AG—Germany (carbon black); Special Black 1000, ex. Orion Engineered Carbons GmbH—Germany (carbon black).

[0108] In one embodiment, the heat trapping agent comprises, in addition to a black body-type of material, a metal powder. This metal powder is at least one selected from zinc, tin, iron, aluminium, tungsten, titanium, zirconium, niobium, boron, any transition metal powder, and any combination thereof. Its role is to increase the anti-corrosion properties, to increase the heat conductivity, and the resistance at high temperatures.

[0109] In one embodiment, the solid layer coating at least partially, preferably most of, or entirely the inside walls of the reactor, which comprises the black body material, is prepared from a colloidal solution by the sol-gel method: this is a mixture of a solute (around 100 g) consisting of graphite powder and the optional metal powder, preferably zinc, with diameters of less than 10 μm, preferably about 5 μm, and an inorganic water-based binder, preferably an inorganic silicon water-based paint, and a solvent (around 500 mL) consisting of water and an organic solvent like an alcohol, glygol, ethanol, isopropanol. The inner surface of the reactor is painted with this colloidal solution containing the black body material in order for that black body material to store the maximum amount of heat.

[0110] The term “colloidal solution” refers to a solution in which a material is evenly dispersed in a liquid. A colloidal solution may be a foam, defined as gas trapped in a liquid, for example aerosol shaving cream; an emulsion, defined as a liquid dispersed in another liquid, for example milk; or a sol, defined as a solid evenly dispersed in a liquid, for example a dispersion of silica particles in a liquid. Preferably, the colloidal solution is a sol, and the sol gel process is employed.

[0111] In one embodiment, the colloidal solution of the invention is applied to at least partially the inside walls of the reactor by any conventional means, including but not limited to, by brush, by roller, by air-less spraying, by air-spray, by dipping, etc. The coating is typically applied in a dry film thickness of 5-300 μm.

[0112] The term “particle diameter D90 of less than 10 μm” describes the diameter where ninety percent of the distribution has a particle size smaller than 10 μm and ten percent of the distribution has a larger particle size. The particle size distribution of the materials may alternatively be measured using a Helos® Sympatec GmbH laser diffraction apparatus. The parameter D90 is equivalent particle diameters for which the volume cumulative distribution, Q3, assumes a value of 90%.

[0113] Preferred inorganic silicon water-based paints include polysiloxanes due to their excellent resistance to ultraviolet light, high temperature (500° C.), oxidation and corrosion. Polysiloxanes have a number of other properties that make them a good choice as coating binders, such as being adhesion promoters and form tenacious bonds with metal. In addition, inorganic polysiloxanes are not combustible.

[0114] The polysiloxanes used as a binder system in the present invention comprise at least one curable, polysiloxane modified constituent, wherein a major part of the binder system consists of polysiloxane moieties, i.e. at least 20% by volume solids, such as at least 25% by volume solids , preferably at least 35% by volume solids, e.g. more than 50% by volume solids, of the binder system is represented by polysiloxane moieties.

[0115] The polysiloxane moiety should be construed to include any pendant organic substituents, such as alkyl-, phenyl-, saturated cyclic structures, or a combination thereof, and may also comprise curable substituents, examples hereof are alkoxy groups, unsaturated acrylic groups, and the like.

[0116] In one embodiment, the polysiloxane has pendant or terminal amino groups, a.k.a.amino-functional polysiloxanes and aminosilanes.

[0117] Other suitable polysiloxane systems are e.g. described in WO 96/16109, WO 01/51575 and WO 2009/823691.

[0118] The colloidal solution typically comprises a solvent. Examples of solvents are water; alcohols, such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol or benzyl alcohol; alcohol/water mixtures, such as ethanol/water mixtures; aliphatic, cycloaliphatic and aromatic hydrocarbons, such as white spirit, cyclohexane, toluene, xylene and naphtha solvent; ketones, such as methyl ethyl ketone, dimethyl ketone, diethyl ketone, acetone, methylacetate, ethylacetate, propylacetate, methyl isobutyl ketone, methyl isoamyl ketone, diacetone alcohol and cyclohexanone; ether alcohols, such as 2-butoxyethanol, propylene glycol monomethyl ether and butyl diglycol; esters, such as methoxypropyl acetate, n-butyl acetate and 2-ethoxyethyl acetate; and mixtures thereof.

[0119] The heat trapping composition coating the inside walls of the reactor is combined with a mixture of gases, which disperses the heat inside the reactor after absorbing it from the heat trapping composition. Heat is dispersed quickly reaching all the matter inside the reactor.

[0120] The term “thermal conductive gas” refers to a gas that conducts or transfers heat. Light gases, such as hydrogen and helium typically have high thermal conductivity. Dense gases such as xenon and dichlorodifluoro-methane have low thermal conductivity. The role of the catalytic thermal conductive gas is to transfer the heat trapped from the inner surface of the reactor inwards the materials that are to be treated.

[0121] Alternatively, the catalytic system of the present invention comprises two main components: at least one nanofluid material, and at least one thermal conductive gas.

[0122] The term nanofluids refers to fluids containing nanometer-sized particles, called nanoparticles. These fluids are engineered colloidal suspensions of nanoparticles in a base fluid. The nanoparticles used in nanofluids are typically made of metals, oxides, carbides, or carbon nanotubes. Common base fluids include water, ethylene glycol and oil.

[0123] Preferably, the catalytic system of the present invention comprises (i) nanofluids aqueous solutions and ii) at least one thermal conductive gas supplied into the reactor.

[0124] In one embodiment the nanofluid aqueous solution used is a mixture of titanium dioxide nanoparticles, sodium dodecylsulfate and water (10 g of titanium dioxide, concentration of dodecylsodium sulfate=1 mol per liter).

[0125] In one embodiment the nanofluid used is a mixture of other inorganic oxide (Mgo, FeO . . . etc), sodium dodecylsulfate and water.

[0126] This heat transfer is possible and enhanced by the gas state of matter and the thermal conductivity properties of the selected gas or mixture of gases or nanofluids. This allows that the transfer of heat occurs to all parts of the material which is to be processed. For this purpose the gas or nanofluid must have a relatively high thermal conductivity and at the same time should be able to cross the compacted materials inside the reactor, reaching all parts of the material at a desired speed. Hydrogen possesses the highest thermal conductivity among the gases. Helium has also a high calorific conductivity. Because manipulation of hydrogen may result in explosion, it is preferably mixed with other suitable gases such as helium, in a ratio of 1-2 parts of hydrogen to 10-1000 parts of helium (w/w), preferably 1/1000 (w/w), also preferably 10/1000 (w/w). Typically the helium is injected directly from a bottle of helium into the reactor. The hydrogen can be generated from a chemical reaction between a hydride which is injected as powder inside the reactor and the humidity (water) present inside the reactor. After contact with water the reaction gives rise to following reactions:

NaBH.sub.4+2 H.sub.2O.fwdarw.NaBO.sub.2+4H.sub.2

NaBH.sub.4+4 H.sub.2O4H.sub.2+NaB(OH).sub.4

[0127] The term “hydrogen-generating powder” refers to a powder or powder mixture, that generates hydrogen when contacted with a suitable agent, for example an aqueous solution. An example of hydrogen-generating powder is a hydride. The hydride may be selected from sodium borohydride, sodium hydride, potassium hydride, lithium aluminium hydride, and the like.

[0128] Alternatively to hydrogen, CO.sub.2 or other high thermal conductivity gases can be used, but with different ratios than the Hydrogen/Helium ratio stated above. The gas or mixture thereof must be injected during each cycle.

[0129] The below table sets out other possible alternatives that can be used in the reactor.

TABLE-US-00002 Gases (ambient temperature Thermal conductivity and atmospheric pressure) (mw .Math. cm.sup.−1 .Math. k.sup.−1) Argon 0.16 CO.sub.2 0.146 CO 0.232 Ethylene 0.17 Helium 1.42 Hydrogen 1.68 HCL 0.13 H.sub.2S 0.13 Neon 0.46 Reference CRC Handbook of chemistry and physics 50 the R. C. Weast Ed the chemical Rubber Co 1969

[0130] The following table sets out the different thermal conductivities of the gases: Hydrogen, Helium and CO.sub.2, at different temperature and pressure levels.

TABLE-US-00003 Temperature Pressure Thermal conductivities (K) (bar) gas (mw .Math. cm.sup.−1 .Math. k.sup.−1) 350 1 H.sub.2 1.686 350 1 He 1.42 350 1 CO.sub.2 0.25 750 1 H.sub.2 3.2 750 1 He 2.8 750 1 CO.sub.2 0.49 750 10 H.sub.2 7.3 750 10 He 6.34 750 10 CO.sub.2 1.2

[0131] The coefficient of thermal conductivity of the catalysts permits routing the heat to all points in the material present inside the reactor and leads to the carbonization of the organic materials by breaking the C—C bonds.

[0132] In one preferred embodiment, the working temperature of the invention is about 450° C. and the working pressure is about 10 bar. As shown in the above table, at this temperature and pressure level, the thermal conductivity of hydrogen and helium in the gaseous state are higher than those of CO.sub.2 and other gases. Thus, there is an advantage in using these gases to transfer the heat more efficiently from the inner walls in the reactor to the compressed materials.

[0133] Equipment

[0134] The system, device, tank, vessel, apparatus, or reactor can be made out of anti-rust metal, like stainless steel, or an iron-contanining material suitable for heat induction, or any other metal capable of sustaining temperatures up to 500° C. Implementing this invention is done by manufacturing special machines based on the above mentioned specifications to process waste and transforming it into carbon while moisture transforms into distilled water. Machines with different capabilities can be manufactured. Typical capabilities may be, without being limited to, 20kg/15 min, 1,000kg/15 min and 3,500kg/15 min.

[0135] The main components of these machines are: [0136] the anti-rust metal vessel or reactor, preferably of cylindrical shape, which is a container that can withstand the heating and pressure conditions of the invention; [0137] a heating system or mechanism which can be powered from different energy sources, such as but not being limited to, electricity, gas, fuel oil, the carbon generated by the machine itself or other ways, and providing sufficient heat to achieve the required temperatures of the process of the invention, the sufficient heat may be in the order of 1000 to 5000 W, preferably around 2000 W; [0138] air pressure system, for example a compressor, which can ensure a working pressure of at least 3 bars, preferably at least 8 bars or at least 10 bars, along with the proper safety release valves, and a pressure controller may be implemented for the regulation and monitoring of the pressure; [0139] the catalytic heat trapping composition mentioned above to expedite the heating process and absorb as much of the required heat. This catalytic heat trapping composition is preferably painted onto the internal walls of the reactor only one time during the production of the reactor. There is usually no need for further coating the inside walls after different cycles, as the above-mentioned coating does not usually deteriorate with the repeated use of the machine; [0140] an inlet to supply or inject the thermal conductive gases, including those precursors like hydrogen-generating powders, which transfer the heat from the reactor walls to all the components of the organic material inside the reactor; [0141] possibly, a dispenser to contain and dispense the nanofluids during the carbonization process; [0142] an outlet to release the water vapour generated inside the reactor; [0143] an activated charcoal filter to remove the undesirable compounds and odors such as carbon powder which is ejected during the depressurization of steam water or some volatile compounds which can be formed before the carbonization; [0144] a cooling system; [0145] optionally a system to separate outgoing air from water; [0146] one or two doors to deposit the waste and to extract the resulting carbon.

[0147] Alternatively, these machines may comprise for the heat transfer at the place of catalyst gases or nanofluid, an agitation system in order to insure the contact of the organic material with the internal surface of the body of the reactor.

[0148] Process

[0149] The combination of all the above mentioned components allows this new technology to treat and transform organic waste, including but not limited to, municipalities solid waste, most hospital waste, expired drugs, slaughterhouse waste, sludge collected from sewage, and industrial organic waste into carbon within 5 to 35 minutes without any toxic emissions.

[0150] The carbonization is achieved in two steps. In the first step, as the heat builds up inside the reactor due to the use of the catalytic system of the invention comprising the coating with the heat trapping composition and the thermal conductive gas(es) mentioned above, or due to the use of the catalytic system of the invention comprising a mixture of the thermal conductive gas(es) mentioned above and nanofluid solutions, the humidity present in the waste starts to evaporate. This vapor can then be collected and cooled outside the reactor to result in distilled water. This makes the waste completely dry (i.e. 99 to 100% dry). Typically, carbon represents the majority of this dry material's chemical composition.

[0151] In a second step, and once the temperature reaches the appropriate level of at least 250° C., preferably from 350 to 450° C., even up to 500° C., and the pressure is at its appropriate level of at least 3 bar, preferably 8 bar, more preferably 9 bar, even more preferably 10 bar, the flash point is reached and the molecules that make up the waste material are cracked to transform the waste into carbon. As long as the temperature and the pressure are maintained at the required levels, the carbonization process starts and takes from 5 to 35 minutes. Once the cycle is complete, non-organic materials such as metal and glass, which do not transform to carbon, are easily separated from the carbon. This avoids the need to extensively sort the waste prior to treating it with the method of the present invention. No toxic emissions are produced throughout the whole process, thus being an environmentally friendly process. In addition, the obtained carbon can be used as a new source of bio-fuel energy.

[0152] In a preferred embodiment, the first step of heat build up, conconmitantly drying the material, is performed as quickly as possible, preferably in 30 minutes, more preferably in 15 minutes or less.

[0153] Heat

[0154] The present invention depends on heat which needs to reach at least 250° C., preferably between 350 to 450° C. through several possible sources of energy such as electricity, gas, coal or any other appropriate source with the need to accelerate the increase of temperature through the catalytic system of the invention. Heat can be generated and transferred to the reactor from any energy source including but not limited to electricity, gas, fuel oil, coal or any alternatively appropriate source. Heat can also be generated using the Carbon the machine produces itself. Heat inside the reactor preferably reaches 350° C. to 450° C.

[0155] Air Pressure

[0156] Air pressure should be increased to at least 3 bars, preferably to at least 8, 9, or 10 bars. Pressure is used to ensure the waste is transformed to carbon instead of ash by preventing incineration. Although carbon starts forming at pressure of 3 bars, the preferred implementation of the process of the invention is at a pressure of at least 8 bars, preferably 10 bars, at which carbon formation is full.

EXAMPLES

Example 1

Preparation of the Heat Diffusing Catalytic Colloidal Solution and Internal Coating of a Reactor

[0157] Starting materials: Polysiloxane, polysilicon, Graphite 80 mesh, ethanol, and zinc powder were purchased from Merck. Deionized distilled water was locally prepared. The paint was prepared as follows: the graphite powder used in the experiment was man-made graphite with a purity of 98%. The size of the graphite powder particles and of the zinc powder particles was 5 μm or less. The filler materials were the mixture of graphite powder and zinc powder. The colloidal sol was made of 500 ml solvent (400 ml water and 100 ml ethanol) and 100 g of solute composed of graphite powder, zinc powder, and inorganic silicon (polysilicon) water-based paint (polysiloxane or sililoxan). The 100 g solute composition had 25 g graphite, 25 g inorganic silicon, and 50 g zinc. After fifteen minutes stirring, the even sol was formed. Under room temperature and atmospheric pressure, a spraying gun was utilized to spray the prepared sol onto the internal surfaces of a reactor, and then dried in an insulation can at around 100° C. to form a coating of about 350 μm thick.

Example 2

Treatment of Municipal Solid Waste

[0158] Municipal waste processed with our prototype internally coated reactor proved the validity of the invention. 3.5 tons of municipal waste was collected and was inserted into the reactor which was then pressurized and sealed appropriately to avoid any leakage during the carbonization process. We used an electric heater to heat the reactor and an air compressor to maintain the appropriate pressure.

[0159] We started by increasing the pressure to 2 bars, at which moment we started heating the reactor. When internal temperature reached 150-160° C. the pressure increased to 7 bars, and the water present in the reactor started coming out of the reactor as water vapor. At this moment, sodium borohydride powder and helium gas were injected into the reactor. The sodium borohydride reacted with the water still present inside the reactor, thereby generating hydrogen. The mixture of in situ generated hydrogen and injected helium vehiculated the heat from the reactor walls into the waste.

[0160] When temperature started reaching 250-300° C. and pressure was about 9 bars, substantially all water present in the reactor had already been released out of the reactor as water vapour.

[0161] At this moment, additional helium was injected into the reactor and keeping the pressure at 10 bars and the temperature between 350 and 450° C. during 15 minutes.

[0162] After these 15 minutes, heating was stopped and the reactor was allowed to cool to a temperature below 100° C. The reactor was also depressurized. The reactor was opened and a vacuum system was used to recover the resulting product. The resulting product was made almost entirely of carbon with a total weight of only around 700 kg from the corresponding starting material of 3.5 tons and it proved that the internal breaking of the C—C bonds of the organic compounds took place and thus a conversion of organics into carbon was achieved. FIG. 13 shows the carbon obtained from the starting 3.5 tons of municipalities solid waste. FIG. 14 shows the steam water ejected from the reactor containing 3.5 tons waste and submitted to the conditions mentioned above. FIGS. 10A and 10B show a sample of mixed municipal waste before and after its treatment with the process according the invention. As can be seen in the referred FIGS. 10A and 10B, the resulting product is a black material and had no odors.

Example 2a

Treatment of Municipal Solid Waste

[0163] Municipal waste processed with our prototype. 3.5 tons of municipal waste was collected and was inserted into the reactor which was then pressurized and sealed appropriately to avoid any leakage during the carbonization process. We used an electric heater to heat the reactor and an air compressor to maintain the appropriate pressure.

[0164] We started by increasing the pressure to 2 bars, at which moment we started heating the reactor. When internal temperature reached 150-160° C. the pressure increased to 7 bars, and the water present in the reactor started coming out of the reactor as water vapor. At this moment, sodium borohydride powder and helium gas were injected into the reactor. The sodium borohydride reacted with the water still present inside the reactor, thereby generating hydrogen. The mixture of in situ generated hydrogen and injected helium vehiculated the heat from the reactor walls into the waste

[0165] Nanofluids solutions were injected into the material from the beginning of the process (titanium dioxide nanoparticles+sodium dodecylsulfate in aqueous solutions).

[0166] An agitator system was used to mix the materials inside the reactor.

[0167] When temperature started reaching 250-300° C. and pressure was about 9 bars, substantially all water present in the reactor had already been released out of the reactor as water vapour.

[0168] At this moment, additional helium was injected into the reactor and keeping the pressure at 10 bars and the temperature between 350 and 450° C. during 15 minutes.

[0169] After 15 minutes, heating was stopped and the reactor was allowed to cool to a temperature below 100° C. The reactor was also depressurized. The reactor was opened and a vacuum system was used to recover the resulting product. The resulting product was made almost entirely of carbon with a total weight of only around 700 kg for the corresponding starting material of 3.5 tons and it proved that the internal breaking of the C—C bonds of the organic compounds took place and thus a conversion of organics into carbon was achieved.

Example 3

Treatment of Household Waste

[0170] Samples of approximately 1 kg of household waste were introduced into the reactor. Within 15 minutes from placing the household waste inside the reactor and operating it, the resulting material was extracted from the inside of the reactor. All the material had been transformed into coal. Laboratory tests showed that the weight of the coal was 20% to 25% of the original weight of the waste, knowing that the remaining 75% to 80% represented the amount of water inside the waste and the carbon represented 92% to 95% of the remaining dry material after evaporating the water.

[0171] Tests were performed on other kinds of industrial waste like animal meat, animal skin, animal bones, vegetables (FIGS. 8A and 8B), banana fruit (FIGS. 9A and 9B), grains, leather (FIGS. 7A and 7B), polyethylene bottle (FIGS. 6A and 6B), sewage residue (sludge), and expired drugs (FIGS. 5A and 5B), and, just like before, it was shown that after 15 minutes everything was transformed into carbon residue. The resulting product obtained after the carbonization of the different waste samples was analyzed with an Organic Elementary Analysis machine (Flash EA 1112, Thermo Scientific). The elemental analyzer is equipped with two combustion columns, one for the analysis of the carbon, nitrogen, hydrogen and sulfur under high oxygen conditions, while the other column is set up for the oxygen analysis in an oxygen free environment. All of the samples were weighed into either tin or aluminum cups for CHNS analysis or into silver cups for oxygen analysis. The results of the elemental analysis are shown in the Table below:

TABLE-US-00004 Sample number % N % C % H % S 1 0 98 0 0.2 2 0 98.5 0 0.1 3 0 94 0 0 4 0 97 0 0 5 0 93 0 0.07 6 0 97.5 0 0.5 7 0 99 0 0 8 0 98.8 0 0

[0172] The results presented in the above table show that the majority of the dry material is carbon and the residual part is constituted by several minerals like potassium, calcium or others nontoxic compounds. The elemental analysis of the samples after their treatment with the process of the invention showed that 90% to 98% of the resulting product was high-purity carbon, depending on the initial waste materials tested. In addition, the weight of the resulting product after the treatment according to the invention, is 20% to 25% of the initial waste before treatment.

Example 4

Effect of Temperature on Carbon Formation

[0173] To test the effect of temperature on the carbon formation, the pressure inside the reactor was fixed at 10 bars and the temperature was changed from 150° C. to 450° C. For each value of temperature a sample was withdrawn and analyzed by the Organic Elementary Analyzer (Flash EA 1112, Thermo Scientific).

[0174] We made several tests on the same amount of organic waste which was carbonized for 15 minutes under different temperatures. For each test, analyses in the Flash EA 1112 machine were conducted to identify the percentage of carbon.

[0175] All the obtained results were combined in a graph (FIG. 11) by plotting the mass of carbon obtained in each sample in function of the temperature. FIG. 11 shows that the percentage of carbon formation increases with the increase of the temperature to reach the appropriate level at around 350° C., becoming stable at around 400° C.

Example 5

Effect of Pressure on Carbon Formation

[0176] To test the effect of pressure on the carbon formation, after fixing the temperature at 450° C., we made several tests on the same amount of organic waste which was carbonized for 15 minutes while changing the air pressure by one unit bar, starting from 1 to 10 bars. For each test, organic elemental analysis was conducted to identify the percentage of carbon and ash after an equal processing time of 15 minutes.

[0177] All the obtained results depicted in the graph of FIG. 12, show that carbon starts forming when pressure is more than 3 bars, after 4 bars the carbonization starts to become significant, while the high level of carbonization is reached once the pressure reaches 8 bars, preferably 10 bars. At the atmospheric pressure the material was completely burned and it converted into ash. After 4 bars, the ash formation was minimal and some of the organic material was converted into carbon instead. FIG. 12 shows the evolution of the carbonization in function of pressure change.