Abstract: A system and process for producing biofuel from spent coffee grounds (SCGs) comprises the steps of performing a first operation comprising the steps of obtaining spent SCGs from a source, washing the SCGs, mixing the washed SCGs with an inorganic acid and heating and stirring the washed SCGs to form a SCG slurry without separating coffee oil, drying the SCG slurry, mixing the dried slurry with a solvent and heating the dried slurry and solvent mixture to create a reaction to produce biofuel and residual grounds, and separating the biofuel from the solvent and the residual grounds. The process further includes the step of using an activation agent and heating the residual grounds and the activation agent to create activated residual grounds. Biochar is also produced without activation and heating de-oiled SCGs at lower temperatures without oxygen.

Abstract: A thermal process for carbonizing hemp and reducing particle size, mechanically, by grinding or milling said carbonized hemp materials to generate a precise particle size hemp char and combining the hemp char particles with a polymer into a master batch.

Abstract: A system and process for producing biofuel from spent coffee grounds (SCGs) comprises the steps of performing a first operation comprising the steps of obtaining spent SCGs from a source, washing the SCGs, mixing the washed SCGs with an inorganic acid and heating and stirring the washed SCGs to form a SCG slurry without separating coffee oil, drying the SCG slurry, mixing the dried slurry with a solvent and heating the dried slurry and solvent mixture to create a reaction to produce biofuel and residual grounds, and separating the biofuel from the solvent and the residual grounds. The process further includes the step of using an activation agent and heating the residual grounds and the activation agent to create activated residual grounds. Biochar is also produced without activation and heating de-oiled SCGs at lower temperatures without oxygen.

Abstract: Exemplary techniques disclosed provide a heat transfer element adapted for use in a rotary furnace for torrefaction and particle size reduction of biomass material. The heat transfer element is made up of a rounded object having a specific gravity substantially higher than a specific gravity of the biomass material to be torrefied, a heat capacity sufficient for the heat transfer elements in the rotary furnace to heat the biomass material to be torrefied, and a hardness sufficient for the heat transfer element to serve as grinding media to reduce the particle size of the biomass material to be torrefied. The heat transfer element has one or more surface features pre-formed in a surface of the rounded object. The surface features are configured to increase traction between the heat transfer elements and the biomass material to be torrefied.

Abstract: Techniques, systems, apparatus and material are disclosed for generating renewable energy from biomass waste while sequestering carbon. In one aspect, a method performed by a reactor to dissociate raw biomass waste into a renewable source energy or a carbon byproduct or both includes receiving the raw biomass waste that includes carbon, hydrogen and oxygen to be dissociated under an anaerobic reaction. Waste heat is recovered from an external heat source to heat the received raw biomass waste. The heated raw biomass waste is dissociated to produce the renewable fuel, carbon byproduct or both. The dissociating includes compacting the heated raw biomass waste, generating heat from an internal heat source, and applying the generated heat to the compacted biomass waste under pressure.

Abstract: A styrene monomer reclamation process and system is described. The styrene monomer reclamation process includes providing a waste plastic. The waste plastic includes styrenic polymers. The waste plastic is formed into polymer particles. At least a portion of the polymer particles are dissolved in a solvent to form a polymer stream. The dissolved polymer particles are depolymerized to form a styrene monomer stream.

Abstract: Embodiments of the invention provide a heat transfer element adapted for use in a rotary furnace for torrefaction and particle size reduction of biomass material. The heat transfer element is made up of a rounded object having a specific gravity substantially higher than a specific gravity of the biomass material to be torrefied, a heat capacity sufficient for the heat transfer elements in the rotary furnace to heat the biomass material to be torrefied, and a hardness sufficient for the heat transfer element to serve as grinding media to reduce the particle size of the biomass material to be torrefied. The heat transfer element has one or more surface features formed in a surface of the rounded object. The surface features are configured to increase traction between the heat transfer elements and the biomass material to be torrefied.

Abstract: The method produces a hydrocarbonaceous fluid (a liquid mixture of hydrocarbons, or in other words a mixture of hydrocarbons which is liquid at ambient room temperature and atmospheric pressure), which functionally is a liquid hydrocarbon fuel, from a feed of waste plastic. The method can comprise the steps of: (step 1) melting a feed of substantially solid waste plastic in an aerobic atmosphere (for instance, air) whereby a waste-plastic melt is produced; (step 2) distilling at least a portion of the waste-plastic melt whereby a hydrocarbonaceous distillate is produced; and (step 3) collecting the hydrocarbonaceous distillate. That distillate is generally referred to above as a condensate. The method can include the step of comminuting the feed of substantially solid waste plastic into pieces substantially no greater than about 1.5 cm2 prior to step 1. The method can also include the step of adding an effective amount of a cracking catalyst to the waste plastic prior to step 2.

Abstract: Techniques, systems, apparatus and material are described for generating renewable energy from biomass waste while sequestering carbon. In one aspect, a method performed by a reactor to dissociate raw biomass waste into a renewable source energy or a carbon byproduct or both includes receiving the raw biomass waste that includes carbon, hydrogen and oxygen to be dissociated under an anaerobic reaction. Waste heat is recovered from an external heat source to heat the received raw biomass waste. The heated raw biomass waste is dissociated to produce the renewable fuel, carbon byproduct or both. The dissociating includes compacting the heated raw biomass waste, generating heat from an internal heat source, and applying the generated heat to the compacted biomass waste under pressure.

Abstract: A process and a unit for fluidized bed torrefaction and grinding of particles of a biomass with a largest dimension of 2 cm to 5 cm, and which unit contains an envelope having a general shape of a sector having a) two substantially vertical walls delimiting that sector; and b) at least one inclined wall defining three zones, from bottom to top: a lower zone provided with a fluidization means, and provided with a grinder placed at the bottom of that zone; an intermediate zone (2) provided with a fluidization means; and an upper zone (3) provided with a fluidization means; and a pipe (11) for introducing the particles reaching into the unit to the level of the intermediate zone.

Abstract: Pyrolysis fuels and methods for processing pyrolysis fuel are provided. In one embodiment, a method of processing pyrolysis fuel converts biomass to pyrolysis fuel including pyrolysis oil and char particles. Also, the method includes resizing a portion of the char particles so that substantially all resized char particles have a largest dimension no greater than about 5 microns.

Abstract: A biomass thermal conversion system including a fixed bed drying zone; a fixed bed pyrolysis zone fluidly connected to the drying zone; a combustion zone fluidly connected to the pyrolysis zone by a material path; and a comminution mechanism arranged across the material path between the pyrolysis zone and the combustion zone, configured to grind char off a pyrolyzed surface of solid biomass and reduce a dimension of the solid biomass below a threshold size.

Abstract: A pyrolysis plant 20 comprises a grinding pyrolyser 22, being a machine or apparatus in which both particle size reduction and pyrolysis occur simultaneously. Plant 20 also comprises a bin (hopper) 30 for holding wet particulate biomass feedstock. Chute 32 leads from the bin 30 to a biomass dryer 34 which reduces moisture content of the feedstock as low as possible, e.g., to below about 10. Dried feedstock is conveyed from dryer 34 via line 36 to a dried biomass feedstock hopper 38. Dried feedstock is fed from hopper 38 into a chute 40 which leads to an inlet trunnion 42 of grinding pyrolyser 22. A discharge trunnion 44 of grinding pyrolyser 22 leads to a char holder 60 for collecting char particles and a condensation train 62 for condensing vapour generated by the pyrolysis to produce oil.

Abstract: A biomass fractionator and method are described for inputting ground biomass and outputting several vapor streams of bio-intermediate compounds along with syngas and biochar. One such biomass fractionate comprises: means for receiving ground biomass into the system; and a plurality of biomass processing stations including means for heating the biomass and subjecting the biomass to biofractioning, and means for collecting residual carbon and biochar.

Abstract: A system and method of converting tires or other solid carbon based material is disclosed, including providing a chamber, feeding the solid carbon based material into the chamber, rotating the chamber, heating and reducing the material in the chamber, collecting solid residue from the chamber, collecting vapor from the chamber, and converting vapor collected from the chamber to a liquid. In an embodiment, the material includes a whole tire. The tire is heated in the chamber causing the tire to collapse and liquefy, exposing the metal in the tire which aids in grinding the carbon material in the tire as it tumbles, collecting solid residue, for example tire carbons, and collecting vapor, for example vaporized oil, and benzene and methane gas from the chamber and converting the oil. The chamber may be heated to a temperature from about 350° F. to about 1100° F. using gases reclaimed from the material.

Abstract: A biocoke producing apparatus has a reaction vessel that has a preset temperature range and pressure range for, without carbonizing of the pulverized biomass, inducing a pyrolytic or thermal curing reaction of lignin and hemicellulose thereof. The reaction vessel has a pressurization device for pressurizing to the pressure range, a heating device for heating to the temperature range in the state of the pressurization and a cooling device for cooling after maintaining of the above state. Multiple reaction vessels are provided. A pulverization delivery conveyor is provided superior to these reaction vessels, and each of the multiple reaction vessels is connected via a connection tube to the conveyor. The connection tube is provided with a pulverizate charging device for charging a given amount of pulverized biomass in accordance with a timing of pulverizate charging to the reaction vessels.

Abstract: A composition of biomass material is disclosed. The composition includes: (i) a lignocellulosic material; and (ii) at least one member selected from a group consisting of potassium, sodium and chlorides, wherein said at least one member comprising not more than about 0.01% (by weight) of said composition. The composition may not include more than 10% of water.

Abstract: Techniques, systems, apparatus and material are disclosed for generating renewable energy from biomass waste while sequestering carbon. In one aspect, a method performed by a reactor to dissociate raw biomass waste into a renewable source energy or a carbon byproduct or both includes receiving the raw biomass waste that includes carbon, hydrogen and oxygen to be dissociated under an anaerobic reaction. Waste heat is recovered from an external heat source to heat the received raw biomass waste. The heated raw biomass waste is dissociated to produce the renewable fuel, carbon byproduct or both. The dissociating includes compacting the heated raw biomass waste, generating heat from an internal heat source, and applying the generated heat to the compacted biomass waste under pressure.

Abstract: This invention relates to systems and methods for converting biomass into highly inert carbon. Specifically, some embodiments densify the carbon into anthracite-style carbon aggregations and store it in geologically stable underground deposits. The use of certain embodiments yield a net effect of removing atmospheric carbon via the process of photosynthesis and converting it into hard coal, which can be stored in underground beds that mimic existing coal deposits which are known to be stable for thousands of years.

Abstract: A solidified biomass consisting of semi-carbonized or pre-semi-carbonized solid matter is pressure-formed from raw biomass material while being heated and has a maximum compressive strength of 60-200 MPa and calorific value of 18-23 MJ/kg. A method for producing the solidified biomass: includes crushing raw biomass material; loading a barrel with the crushed raw biomass material; inserting a pressure applying piston into a hollow of the barrel; pressure-forming the crushed raw biomass materials by applying pressure with the pressure applying piston while heating the material; obtaining semi-carbonized or pre-semi-carbonized solid matter by retaining constant time of the heating and the pressurizing; cooling the semi-carbonized or pre-semi-carbonized solid matter while maintaining pressure to obtain a cooled solid; and taking out and drying the cooled solid, wherein the pressure applying piston and the hollow of the barrel have very small clearance between their outer and inner peripheries.

Abstract: A Feeding apparatus for a pyrolytic reactor, comprising a rotatable inclined drum, a motor for rotating the drum, a hopper by which aggregatable feedstock pieces introduced to the interior of said drum, and a feed tube extending from the drum to a pyrolytic reactor. The rotation of the drum applies forces of sufficient magnitude and varying direction to an aggregated mass of feedstock pieces that constituent feedstock pieces are separated from said aggregated mass and are discharged from the drum via the feed tube to the pyrolytic reactor.

Abstract: This method of upgrading a biomass comprises: an upgrading step for performing upgrading treatment of a cellulose based biomass with an oxygen/carbon atomic ratio of at least 0.5, in presence of water and under a pressure of at least saturated water vapor pressure, and reducing said oxygen/carbon atomic ratio of said biomass to no more than 0.38, and a separation step for separating an upgraded reactant obtained from said upgrading step into a solid component and a liquid component.

Abstract: A process of manufacturing powdered coffee carbons from spent coffee grounds comprising washing spent coffee grounds, dehydrating same, and conveying same to a pre-carbonation oven for drying and pre-carbonization; removing the pre-carbonized spent coffee grounds, soaking same in a solution mixed with a predetermined quantity of sodium carbonate for a predetermined period of time for grease removal, and washing the grease free spent coffee grounds; pouring the pre-carbonized spent coffee grounds into a post-carbonization oven and heating same to the range of 600 to 650° C. to carbonize the pre-carbonized spent coffee grounds wherein the carbonized spent coffee grounds have a porous structure; supplying saturated steam between 850 and 950° C. to the carbonized spent coffee carbons for activation; and operating a wet global grinder to grind the activated spent coffee carbons until powdered coffee carbons having a size between 0.1 and 20 ?m are obtained.

Abstract: The claimed invention relates to an apparatus and method for restoring plastic, to oil, thereby efficiently recycling waste plastic. The apparatus comprises a decomposer, an oil reduction body, a cooling tank, and a filter and emission part. The decomposer comprises a decomposition space comprising an opening to receive the plastic, a heating coil inside the decomposer to heat the decomposition space to pyrolyze the plastic, and a pyrolyzing gas exhaust pipe in an upper part of the decomposer connected to the decomposition space to exhaust pyrolyzing gas produced in pyrolyzing the plastic. The oil reduction body positioned in one side of the decomposer is divided into a cooling space and a oil catchment space by a partition. The cooling space is connected to the pyrolyzing gas exhaust pipe to receive the pyrolyzing gas from the decomposition space.

Abstract: A method for the reduction of mercury emissions from an industrial plant that utilizes a cement or minerals kiln that has a high level of mercury emissions during specific operating conditions. The invention reduces a large spike in mercury emissions typically seen in cement kiln systems when the in-line raw mill is shut-down and all preheater gases are vented to the stack directly. The invention diverts the preheater gases to a cooling device that functions as an adsorption reactor to provide mercury absorption during periods when the raw mill is not in operation.

Abstract: A system and process for the production of combustible substances by means of depolymerisation of rubber products, comprising a depressurized depolymerising device (1), inside which it takes place the depolymerisation of a predetermined quantity of products introduced at its inner, characterized in that it comprises a divider or phases separator (2) disposed downstream said depolymerising device (1), which consists of a substantially cylindrical body, with an upper base (20) and a lower base (21), and is connected with the depolymerising device (1) by means of a pipe (3): said phases separator (2) being apt to carry out the separation of at least a part of the liquid phase of the products exiting the depolymerising device (1), and having an outlet (23) for the thus separated liquid phase and an outlet (24) for the remaining part of the products in mostly gaseous phase.

Abstract: A retort heating apparatus for processing a feed material includes a heating chamber bounded at least in part by a side wall. A plurality of baffles are at least partially disposed within the heating chamber. Each baffle includes an elongated body having a top surface, at least a portion of the top surface being arched. The plurality of baffles are vertically and horizontally spaced apart so that substantially all of the feed material that vertically passes through the heating chamber is horizontally displaced as the feed material passes by the baffles. Systems are also provided for heating the feed material within the heating chamber.

Abstract: A method and apparatus for processing a waste product and producing a synthesis gas is provided. The system includes a sealed, heated rotatable drum for preheating and preparing the waste material suitable for a plasma reactor, and processing the material in the reactor. The synthesis gas created by the reactor is used to preheat the waste material by circulating the hot synthesis gas around the drum. In an alternative embodiment, the hot synthesis gas flows through the drum to preheat the waste material and to clean the synthesis gas. Different methods of cooling and cleaning the synthesis gas are used. The system may comprise two plasma reactors in combination with a rotating desorber drum.

Abstract: Closed apparatus and processes by which carbon feedstock, is composed of a mixture of non-coking coal fines and another carbonaceous material, such as waste coke fines are disclosed. The coal and coke fines are mixed together and may be formed into solid pieces. The mixture alone or as solid pieces is fired through pyrolyzation into solid pieces of coke, with solid and gaseous by-products of pyrolyzation being recycled for use within the coke-producing closed system, thereby reducing or eliminating release of undesirable substances to the environment. A char-forming binder may or may not be added to the carbon mixture prior to pyrolyzation.

Abstract: A method and apparatus for processing a waste product and producing a synthesis gas is provided. The system includes a sealed, heated rotatable drum for preheating and preparing the waste material suitable for a plasma reactor, and processing the material in the reactor. The synthesis gas created by the reactor is used to preheat the waste material by circulating the hot synthesis gas around the drum. In an alternative embodiment, the hot synthesis gas flows through the drum to preheat the waste material and to clean the synthesis gas. Different methods of cooling and cleaning the synthesis gas are used. The system may comprise two plasma reactors in combination with a rotating desorber drum.

Abstract: A thermolysis process for the production of volatiles for an external combustor or liquefaction of biomass solids in which specific and previously unrecognized conditions are employed. The thermolysis is carried out in a single fluidized bed of inert material operating at near atmospheric pressure, relatively low temperature, long solids and gas residence times and moderate heating rates. The distribution of the thermolysis products among, solid (char) and gases under these conditions is unique. The product effluent can be either quenched to produce a high liquid yield in addition to a low char yield or the volatile effluent can be used in either the same combustor or a second combustor to produce heat energy a particularly high efficiency system. In using a quencher, the quenched liquid is of similar composition to those obtained by so called fast pyrolysis processes of the prior art. The specified conditions are such as to allow production of liquids in high yields in an energy efficient manner.

Abstract: A method of thermally treating plastics material includes the steps of heating a treatment chamber at least to the melting point of at least a fraction of the plastic material, maintaining an oxygen level in the treatment chamber below combustion level of liquid or gaseous products from the plastic material, feeding the plastic material into the treatment chamber at a rate ensuring a built-up of a film of liquified plastic material on at least a part of the interior of the surface of the treatment chamber, with the liquified plastic material undergoing a transition into the gaseous phase as a result of the heating of the treatment chamber, and exiting of the gaseous phase out of the treatment chamber caused by vaporization pressure of the gaseous phase within the treatment chamber.

Abstract: Used batteries and other material for reclamation and recovery or environmentally safe disposal are transferred from a feed bin by an auger into a crusher and then into a pyrolysis chamber. The feed system excludes air or oxygen from passing through the auger and crusher into the pyrolysis chamber. The material from the crusher is transferred by an auger through the pyrolysis chamber which is heated to a decomposition temperature between 350.degree. and 650.degree. F. and is decomposed. The pyrolysis chamber includes a vapor recovery system for removing the vapors and maintaining a vacuum in the pyrolysis chamber. The vapors are withdrawn through a heat exchanger and into the liquid/gas separator where the condensed liquids are removed and the gas is further processed. The residue from the pyrolysis chamber is discharged into a residue recovery system which includes a closed auger for transferring the residue from the pyrolysis chamber into a bin.

Abstract: A method for producing a solid fuel from combustible waste includes sorting and grinding the waste, treating the waste by heating in the absence of oxygen in a first pyrolysis reactor and then collecting the waste so treated. Polluting elements in the gases emerging from the pyrolysis are removed while the gases are hot before being directly reused to heat a first pyrolysis reactor so that solids leaving the pyrolysis operation provide a fuel without the pollutants initially contained in the waste. The device for carrying out this method includes a pyrolysis reactor and a unit for supplying an absorbent to a zone wherein the gases generated by pyrolysis are contacted by the absorbent to remove the polluting elements; the absorbent and the decontaminated solids are separated from each other.

Abstract: A carbonization apparatus for carbonizing material which includes metal parts, as for instance waste material with elongated metal parts, such as metal wires and metal bands. A residue discharge pipe has a discharge port formed in an end face thereof. Carbonization residue is discharged through the discharge port. The residue discharge pipe rotates about its longitudinal axis. The metal parts are entrained with a device which is disposed in a region of the discharge port and which rotates with the residue discharge pipe. In the alternative, the entrainment device or devices are disposed inside a carbonization drum. A stationary bar-shaped member cooperates with the entraining device to tear the metal parts discharging from the discharge opening.

Abstract: An improvement is proposed in an anisotropically electroconductive adhesive composition comprising an insulating adhesive resin as a matrix and electroconductive carbon particles dispersed in the matrix used for electrically connecting oppositely facing electrode terminals on various kinds of electronic devices and circuit boards. Different from conventional spherical carbon particles, the conductive particles used here are carbon particles each having a plurality of projections on the surface as formed, for example, by the high-temperature calcination of spherical carbon particles blended with a tar or pitch. By virtue of the projections on the carbon particles, the electric connection formed by using the inventive adhesive composition is very reliable and durable even under adverse ambient conditions involving a high temperature, high humidity, vibrations and mechanical shocks by virtue of the anchoring effect by the projections.

Abstract: A method for generating, from refuse or refuse in combination with coal, a fuel gas suited for public utility purposes wherein refuse and coal can be introduced into the process in any proportion one to the other. The method provides the steps of subjecting the refuse to allothermal low-temperature carbonization, if desired in combination with coal, burning the gasification residue, purifying the crude gas and conditioning the pure gas for public utility purposes.

Abstract: A rotary, continuous pyrolytic conversion system converts solid hydrocarbon containing feedstocks into gases, liquid hydrocarbons and char. A converter drum is contained within an outer drum which is in substantially air-tight relationship with an injector for introducing the feedstock in the form of bales and with a discharge chute for the solid products of pyrolysis. A casing around the outer stationary drum defines an oven chamber which is heated by combustion products. A rod extends into the injection end of the converter drum for supporting scrapers against the inner periphery of the converter drum. A crusher bar is carried in the drum at the discharge end thereof and crushes the solid products. A second pyrolysis reactor may receive the solid pyrolysis products and be operative at higher temperature than the first converter to destroy chlorinated hydrocarbons.

Abstract: An apparatus and a method are disclosed for the thermal treatment of feed material containing solids and liquids such as solid waste or the like. The apparatus includes one or more coaxial rotatable drums and one or more free rotating spirals advancing the material in the drums. The material flowing through the drums is heated to form solids and vapors. In one or more embodiments of the apparatus, the hot solids and vapors exchange heat with the cold feed material. An extruder for preparing the solids being produced from the apparatus for disposal and a means for rotating the drums are also disclosed.

Abstract: A preferred method of dry cooling coke includes the steps of removing the coke from the coke oven, crushing the coke with a crushing device to increase a surface area thereof, transporting the coke after crushing to a dry cooling apparatus, and dry cooling the coke by the transfer of heat at the surface area which has been increased by the crushing.

Abstract: Carbonaceous raw material, such as lignite coal, having first been passed successively through a moving grate stoker furnace, a shaft furnace and a quench chamber is screened so as to remove from the end product substantially all +12 mesh and larger particles which are then crushed to -12 mesh screen size and recirculated into the stream of raw material enroute through the moving grate stoker.

Abstract: A method for recovering hydrocarbons from oil bearing shale which comprises placing the shale in pulverized form into a retort and simultaneously processing under retorting conditions.

Abstract: Hydrogenation of coal is improved through the use of a mechanical force to reduce the size of the particulate coal simultaneously with the introduction of gaseous hydrogen, or other hydrogen donor composition. Such hydrogen in the presence of elemental tin during this one-step size reduction-hydrogenation further improves the yield of the liquid hydrocarbon product.

Abstract: The invention relates to a method and apparatus for the extraction of petroleum from tar sands, bituminous shale, and other petroleum bearing materials, and the separation of the extracted petroleum into its several fractions.

Abstract: In a method and apparatus for recovering oil products from oil shale and like materials, controlled amounts of raw oil shale are delivered into an upper inlet of a downwardly sloping retort chamber that is constructed as readily portable. The raw oil shale is first moved in a direction countercurrent to gravity flow and crushed in the retort chamber by means of a rotating member that also serves to retain the oil shale in the retort chamber until a satisfactory recovery is completed. The crushed oil shale is confined to a relatively thin, downwardly moving layer in contact with a heated, inner, annular wall surface and moves by gravity flow between the inlet and a lower outlet to produce oil product vapors that rise to an upper portion of the retort chamber. The moving layer of the oil shale becomes spent as it passes through the retort chamber and finally is selectively discharged through the lower outlet.

Abstract: A method and apparatus for treatment of waste on ships and the like, in the form of solid waste and black water collected in a tank from reduced flush toilets. The solid waste is mixed with black water from the tank in a drum. Rotating knives in the drum effect the disintegration of the solid waste, and also the picking up of the waste in the drum from the bottom thereof to permit it to drop repeatedly by gravity from the upper regions of the drum. A flow of hot air is passed through the drum and hence through the dropping mixed black water and disintegrated solid waste. The axis of the drum is substantially horizontal, and may be slightly inclined with bottom ridges to inhibit the flow of liquids therealong.

Abstract: In the production of formed coke, the temperatures and times of the oxidation and carbonization phases can be reduced if 5 to 12% by volume of oxygen is included in the fluidizing gas in a fluidized bed reactor in which the carbonization phase is conducted.