Abstract: A system for inerting a biomass feed assembly the system including a combustion chamber operably connected to the biomass feed assembly to receive a biofuel, the combustion chamber operable to combust the biofuel and generate a flue gas therefrom and a conduit operably coupled to at least one of the combustion chamber and an inert gas source, and the biomass feed assembly, the conduit operable to carry a gas to the biomass feed assembly. The gas sweeps dust generated in at least the gravity chute assembly toward the combustion chamber and the gas maintains an oxygen partial pressure or concentration in the at least a portion of the biomass feed assembly below a selected threshold sufficient to suppress ignition.

Abstract: A process for fracturing and devolatilizing coal particles rapidly exposes coal particles to a high temperature, oxygen-depleted work zone for a sufficient time period to cause volatile matter within the coal particles to vaporize and fracture the coal particles. The work zone has a temperature in the range from 600° C. to 2000° C. The coal particles are exposed to the high temperature, oxygen-depleted work zone for a time period less than 1 seconds, and preferably less than 0.3 second. The vaporized volatile matter is condensed and recovered as microcarbon particles.

Abstract: The present invention is provided with a step for preheating coal, a step for heating an extraction solvent, a step for mixing the preheated coal and the extraction solvent heated to a higher temperature than the preheated coal and thereby heating the coal, a step for separating a solution in which a coal component is dissolved from the mixture of the coal and the extraction solvent, and a step for evaporating and separating the extraction solvent from the solution.

Abstract: An advanced method and facility for growing abundant crops for food together with a sustainable growth of biomass for energy within a farm setting measuring (by way of example) 600 acres and yielding some 180 bushels of corn per acre, amounting to a total farm yield of 108,000 bushels. By increasing the yield of 180 to 270 bushels per acre with drainage, irrigation, and a pond that accepts water in wet weather and dispenses water for irrigation in dry weather, and supplementing with fertilizer, the 108,000 bushels can be produced with only 400 acres, this freeing 200 acres for growing biomass to be harvested and delivered to a centralized processor (preferably in pellet form) and efficiently converts the biomass into a biofuel rich in H2 for transportation such as gasoline and a low-Btu biofuel to generate biopower while co-producing fertilizer to enhance growth of both crops and biomass.

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 pyrolysis process is provided in which biomass feedstock is mixed with a heat carrier. The heat carrier at least partly comprises char. The ratio by weight of biomass to char is in the range 1:1 to 1:20. The process may be carried out by in a screw/auger pyrolysis reactor in which the solid feedstock components are conveyed along the reactor by a first screw. A second screw conveys at least a portion of the solid products of the biomass pyrolysis back to a heat transfer medium input port. Thus, the heat transfer medium includes char from the biomass pyrolysis.

Abstract: A system includes a feed preparation system, with a fluid injection system configured to inject a fluid into a feed stream to generate a feed-fluid mixture. The feed stream includes a first solid, a second solid, and a gas. The feed preparation system also includes a cyclone configured to separate the feed-fluid mixture into a first stream that includes the first solid and the gas, and a second stream that includes the second solid and the fluid.

Abstract: A biochar generator to be carried by a vehicle may comprise a pyrolysis chamber, an auger, a heater, and a vapor condenser each connected to the pyrolysis chamber. The biochar generator may also include a synthesis gas collection chamber to collect synthesis gas, and a bio oil collection chamber to collect bio oil, each in communication with the vapor condenser. A biochar collection chamber may be included to collect biochar dispensed from the pyrolysis chamber.

Abstract: A process for treating agglomerating coal includes providing dried, pulverized, agglomerating coal, and treating the coal in a vessel with a gas stream having an oxygen content sufficient to form at least some oxides on surface of coal particles, wherein the oxides are sufficient to convert coal into substantially non-agglomerating coal. The treated coal is transferred into a pyrolyzing chamber and passed into contact with an oxygen deficient sweep gas, the sweep gas being at a higher temperature than the temperature of the coal so that heat is supplied to the coal. The process further includes providing additional heat to coal indirectly by heating the chamber, wherein the heating of coal by the sweep gas and by the indirect heating from the chamber causes condensable volatile components to be released into the sweep gas. The sweep gas is removed from the chamber and treated to remove condensable components of coal.

Abstract: The invention relates a pyrolytic carbon black produced from pyrolyzed rubber, the pyrolytic carbon black having an ash content ranging between 9-15%, a toluene discoloration at 425 mu of between 80-90% transmission, an iodine adsorption between 30 and 45 mg/g; and, an n-dibutyl phthalate absorption number of or to 65 cc/100 gm.

Abstract: A self sustaining desalination system includes a chamber having a transparent inclined cover and a transparent bottom for receiving seawater or the like. The system includes a channel for conveying seawater to the chamber and a receptacle for receiving distillate at the base of the cover. The seawater is vaporized by solar energy passing through the incline cover and reflected up through the transparent bottom. A portion of the vaporized water condenses on the cooled inside cover and runs down into the receptacle. A second portion of the vaporized water is fed to the heat exchanger and condensed therein. In addition, a plurality of such systems are combined with a plurality of basic units each of which includes a wind turbine and an array of solar panels in a park like setting to provide electricity, drinking water and irrigation water for a small community.

Abstract: A method for producing non-recovery/heat recovery coke may include the steps of providing a container, disposing a volume of loose coal into the container such that a vertical dimension of the volume of loose coal in the container is smaller than a horizontal dimension of the volume of loose coal, applying a force to the coal in the container to produce a volume of compacted coal having a substantially uniform density which is larger than that of the loose coal, disposing the compacted coal into a non-recovery/heat recovery type oven, and heating the compacted coal to produce coke. The method may also include the steps of providing a container, and moving the non-recovery/heat recovery coke mass from the oven at a substantially constant elevation to the container, quenching the coke mass in the container to produce a quenched coke mass, and removing the quenched coke mass from the container.

Abstract: In a method of producing coke for metallurgy by carbonizing a coal blend obtained by blending plural raw coals in an coke oven, a coal blend containing not less than 60 wt % of a medium coking coal of middle coalification degree and low fluidity having an inert component content of not less than 30% is used as a coal charged into the coke oven, whereby a great amount of raw coal of a brand being cheap and easily available can be blended in a great amount and hence coke for metallurgy having an excellent quality such as strength or the like can be produced by blending few brands of coals as compared with a coal blend of many brands.

Abstract: A method of manufacturing active carbon from regenerated carbon powder by splitting of waste tires including the following steps: (1) regenerating the carbon powder by splitting of the waste tires; (2) using a fluidized bed reactor for further carbonization and activation of the carbon powder; (3) cooling and collecting the carbon powder after reaction. The process of manufacturing promotes reaction and makes uniform heating, thus carbon powder can sufficiently contact steam to speed up and make uniform of the activation, and a complete reaction can be effected.

Abstract: Asphaltene and oil shale are pyrolyzed at substantially atmospheric pressure for producing combustible products and carbonaceous material. A combustor combusts the carbonaceous material and produces flue gases which are supplied to a utilization device, and hot ash which is fed back to the pyrolyzer.

Abstract: The invention relates to a method for producing powdery, vitreous carbon, and a paste made therefrom for producing resistive films having predetermined electrical conductivity. In production methods known in the art, pyrolysis of acrylamides is performed in mixture with water-soluble salts and, following pyrolysis, the powdered portion of the vitreous carbon is recovered by dissolving the salt component in water. The vitreous carbon is then dried, and the powder obtained in this manner is pulverized once again, as needed. A disadvantage of this method is that it is very time-consuming. In the solution now recommended, a preferably aromatic polymer is cured into a resin that is cross-linked in three dimensions, and in this state is ground to a powder prior to pyrolysis. Pyrolysis of the resulting powder is performed in a nitrogen atmosphere, so that powdered, vitreous carbons having different resistivities are obtained by using different final pyrolysis temperatures in each pyrolysis process.

Abstract: The invention concerns a process for recovering synthetic raw materials and fluid fuel components from used or waste plastics in accordance with patent application P 43 11 034,7. At least a partial flow of the depolymer produced according to this process is subjected, together with coal, to a coking process, fed to a thermal utilization system or introduced as a reducing agent into a blast furnace process. The depolymer can be used as an additive for bitumen and bituminous products.

Abstract: The invention relates to a process for recycling waste which consists essentially of one or more plastics comprising polyvinyl chloride (PVC), in which:the waste is mixed with a heavy oil, in a reactor under an inert atmosphere, at an internal temperature of at least 300.degree. C., and the hydrogen chloride (HCl) which is evolved is collected;the contents of the reactor are then cracked at a temperature of at least 400.degree. C., and at least part of the gases which are evolved are extracted from the reactor;the contents of the reactor are then cooled and the residual solid product is collected.HCl, coke, hydrocarbon gases and various oils are thus mainly obtained.

Abstract: Heating of polyvinyl chloride, in particular plasticizer-containing polyvinyl chloride, to a temperature of from 250.degree. to 500.degree. C. in the absence of oxygen gives a low-chlorine, carbon-containing residue, plasticizer and hydrogen chloride.

Abstract: Pieces of coke of high density and strength are made continuously from fine particles of bituminous or subbituminous or lignite coals or of mixtures thereof. The particles are generally oxygenated, mixed with water, compressed to squeeze out some of the water to obtain single bodies which are heat processed lying on a traveling grate on which they undergo drying, pyrolyzing, carbonizing and cooling.Modifications include mixing in with the coal material(s) listed above, coke fines or char or anthracite coal; or limestone; or carbon-reducible oxides such as oxidic ores of Fe, Mn, Cr and quartzite in recited important proportions. Such formed coke bodies are useable in a submerged arc furnace or in a blast furnace or in an open hearth to produce desired intermediate or end metallic products. The pieces of coke with incorporated fine limestone burn without developing SO.sub.2.

Abstract: A method and apparatus of cooling retort coke is disclosed which provides for cooling hot coke from a coking chamber by direct heat exchange with fine-grained material, preferably coal, and the subsequent separation of the fine-grained material from lump coal which would form the cooling step.

Abstract: A upgrading method of low-rank coal containing higher ash and moisture contents into coal decreased in ash content and decreased in moisture content and heightened in heating value includes subjecting the low-rank coal to a low-temperature dry distillation treatment, pulverizing the dry-distilled low-rank coal to form a coal-water slurry and adding a binder to the slurry to effect oil agglomeration of the coal and promote separation of the ash.

Abstract: Green coal is charred in pre- and post- treatment carbonizers, then crushed, mixed with pitch, briquetted, tempered in a tempering oven, recirculated with succeeding green coal to char in a reducing atmosphere through only the latter part of the pre-treatment carbonizer and through the post-treatment carbonizer, cooled, and separated from the as yet unbriquetted char. The pre-treatment carbonization is characterized by having air updrafted through all the airbox zones under the travelling grate.

Abstract: A coal is finely pulverized. The finely pulverized coal is subjected to dry distillation. A tar obtained by the dry distillation is added to an aqueous slurry together with the dry-distilled coal to effect the submerged granulation.

Abstract: In the method, organic, i.e. carbon-containing, material, such as straw, wood chips, sawdust, or dead bacterial waste from a sewage treatment plant, is heated in a pyrolytic reactor, thereby driving off volatiles from the organic material, including hydrogen and carbon monoxide gases, water vapor, and tars, while leaving charcoal (char) behind. The volatiles are then passed over a base material, such as hot char, which is at a temperature substantially above the pyrolizing temperature, e.g. 950.degree. C. and above, which causes a chemical reaction of the tars and volatiles, resulting in an output of a gaseous mixture consisting largely of carbon monoxide and hydrogen, characterized by an absence of tars. The apparatus includes a pyrolytic reactor in which an initial charge of charcoal is located. An inlet is provided for introduction of the organic material and an exit is provided for the resulting gases and ash products.

Abstract: The strength and density of a metallurgical coke produced in a slot coke oven are both increased by replacing at least a part of the normal loose charge in the oven with compacted materials and fragments thereof made from a mixture of particularly sized particulate fusible bituminous coal particles, non-fusible particles of a material compatible with the burden of a blast furnace, and water. During compacting the pressure and the moisture content of the mix are such that at least some water is squeezed out of the mix. The non-fusible materials that are useful include non-coking coals, poorly coking coals, other carbonaceous materials, such as coke breeze, char, anthracite, lignite, and iron oxide-bearing materials, such as iron ores and waste materials from steel plants. At least a major proportion of the fusible particles and at least a substantial proportion of the non-fusible particles are smaller than about 0.15 mm.

Abstract: Process and apparatus for recovering volatile distillates from coal, and other solid carbonaceous fuel sources, by heating the top surface of a bilayer of coal formed of an upper layer of recycled coal and a lower layer of green coal, maintaining the lower level of green coal at a temperature cool enough to condense constituents distilled from the upper layer of recycle coal, and recycling the once passed green coal as recycle coal is disclosed.

Abstract: This invention discloses a process and apparatus for pyrolyzing particulate coal by heating with a particulate solid heating media in a transport reactor. The invention tends to dampen fluctuations in the flow of heating media upstream of the pyrolysis zone, and by so doing forms a substantially continuous and substantially uniform annular column of heating media flowing downwardly along the inside diameter of the reactor. The invention is particularly useful for bituminous or agglomerative type coals.

Abstract: In the continuous production of coke or semicoke from coal grains and/or fines an inclined air-tight rotating tubular oven is fed with coal grains and/or fines from a hopper. As the coal grains and/or fines progress down the rotating oven they are heated by a stoichiometric mixture from a burner and converted into coke or semicoke having a volatile content of from 1% to 20%. During the heating of the coal grains and/or fines the interior of the oven is maintained under a slightly elevated pressure in relation to the atmosphere. The coke or semicoke is then extracted from the oven and passed to an extinguishing device where the coke or semicoke is extinguished to prevent recombustion.

Abstract: This invention discloses a process and apparatus for pyrolyzing particulate coal by heating with a particulate solid heating media in a transport reactor. The invention tends to dampen fluctuations in the flow of heating media upstream of the pyrolysis zone, and by so doing forms a substantially continuous and substantially uniform annular column of heating media flowing downwardly along the inside diameter of the reactor. The invention is particularly useful for bituminous or agglomerative type coals.

Abstract: A method of pyrolyzing and desulfurizing coal in a transport reactor to recover volatile fuel values and hydrogen by heating particulate coal entrained in a carrier gas substantially free of oxygen to a pyrolysis temperature in a zone within three seconds.

Abstract: A heavy high-sulfur hydrocarbonaceous feedstock is partially delayed coked and partially formcoked. The coke products are screened, with larger particles being calcined at desulfurizing temperatures and smaller particles being recycled to the formcoker. Overhead products from both coking operations are combined, fractionated, and desulfurized. The heaviest cut from the fractionator is combined with the feedstock as recycle.

Abstract: Method of mixing particulate materials comprising contacting a primary source and a secondary source thereof whereby resulting mixture ensues; preferably at least one of the two sources has enough motion to insure good mixing and the particulate materials may be heat treated if desired.Apparatus for such mixing comprising an inlet for a primary source, a reactor communicating therewith, a feeding means for supplying a secondary source to the reactor, and an inlet for the secondary source. Feeding means is preferably adapted to supply fluidized materials.

Abstract: In the liquefaction of a sub-bituminous and/or lignitic coal, an ash containing coal liquid is heated to a temperature of from 410.degree. C. to 450.degree. C., and delayed coked adiabatically at a pressure of from 15 psig to 120 psig to produce an ash containing soft coke, having a volatile matter content of above 16% and generally no greater than 30%, all by weight, which is particularly suitable as a blending stock for the production of metallurgical coke.

Abstract: A method of generating gas and coke dust by means of rapid degasification and rapid vaporization, with simultaneous extensive desulfurization, of coal ground into dust. In a first step, one portion of coal is subjected to complete or partial vaporization. In a second step, which immediately follows the first step, another portion of coal is subjected to degasification in the same or in associated reaction chambers. In the degasification, the solid and gaseous products obtained during the vaporization which are at a higher temperature level than that of the degasification step, transfer heat directly to the coal introduced into the degasification step, thus for covering the heat required for the degasification.

Abstract: The present invention is an improvement in the known process of making a coking feedstock from non-caking or weakly caking coals for slot-type coke ovens wherein the coal is subjected to solvent extraction; and at least the non-distillable extract in the effluent slurry product, after removal of part or all of the solvent, is mixed with carbonaceous solids to serve as a binder therefor. The improvement resides in the use of fluidizer char (which is produced by the low temperature carbonization of coal in a fluidized bed) as the carbonaceous solids. The fluidizer char is preferably mixed with the coal extract slurry (after removal of solvent) in a liquid state at elevated temperatures under pelletizing and non-carbonizing conditions. The pelletized product, after cooling and crushing, is suitable as part or all of the coking feedstock for coke ovens.

Abstract: A solid carbonaceous material is pyrolyzed in a descending flow pyrolysis reactor in the presence of a particulate source of heat to yield a particulate carbon containing solid residue. The particulate source of heat is obtained by educting with a gaseous source of oxygen the particulate carbon containing solid residue from a fluidized bed into a first combustion zone coupled to a second combustion zone. A source of oxygen is introduced into the second combustion zone to oxidize carbon monoxide formed in the first combustion zone to heat the solid residue to the temperature of the particulate source of heat.

Abstract: Prior to starting up a plant in which fine coke is produced by mixing high bituminous lignite coal with circulating hot fine coke serving as a heat carrier in the plant, hot inert gas is admitted into the mixing unit in which the coal and coke are admixed. Only after all parts of the plant are thus preheated, the operation of the plant is started up.

Abstract: Bitumen-containing material is processed by distillation with a solid heat-carrier with subsequent gasification of the distillation residue and combustion of the gasification residue in an aerofountain furnace. During gasification, the formed flue gas and ash are heated and part of ash is used as the heat-carrier. The flue gas and ash are withdrawn from the process simultaneously in the form of their suspension in air, from which the heat-carrier is isolated for the distillation process, the consumption of the heat-carrier being controlled by withdrawing part of the suspension containing fine fraction of ash before the heat-carrier is isolated.

Abstract: An improved method for producing calcined coke agglomerates having good stability including adjusting the fluidity of coals or blends of coals to within a range of 1300 DDPM and 3000 DDPM, mixing the coals or blends of coals with char and optionally topped tar in a rotating agglomerating drum and agglomerating the mixture at a temperature between 750.degree. F. and 875.degree. F. (399.degree. C.and 468.degree. C.) for a time to form partially coked green coal agglomerates generally spherical in shape and calcining the partially coked green coal agglomerates at a temperature between 1500.degree. F. and 2000.degree. F. (815.degree. C. and 1093.degree. C). The calcined coke agglomerates are characterized by having a stability of not less than 60%.

Abstract: An improved process for making metallurgical coke is provided as follows. An effluent slurry consisting essentially of coal extract, solvent and undissolved coal is obtained from the liquefaction of coal by solvent extraction. Solvent is removed from the slurry by distillation to produce a bottoms product which contains non-distillable extract, undissolved coal and residual solvent. The bottoms product is flowable at elevated temperatures below its carbonizing temperature and solidifiable at lower temperatures. The bottoms product is blended with sufficient finely divided hot coaly solids (unsuitable per se for making metallurgical coke) in a hot blending zone which is maintained at a temperature above the softening point of the non-distillable coal extract and below the coking temperature thereof to produce a solidifiable product which, in particulate solidified state, serves as part or all of the feedstock to a coking zone to produce coke suitable for use in a blast furnace.

Abstract: Fresh carbonaceous particles are introduced into a fluid-bed reaction zone containing a bed of non-agglomerating particles at an injection velocity in excess of about 200 ft/sec with the fresh particles having been preheated to a temperature within the plastic transformation range of the particles and introduced rapidly and directly into said bed of non-agglomerating particles. The reaction zone may be a hydrocarbonization zone, a carbonization zone, a gasification zone or any other fluid-bed reaction zone in which defluidization may be caused by undue agglomeration of the feed particles. A fluidized stream of the preheated carbonaceous particles may be introduced at said high injection velocity in a vertically upwards direction or otherwise, as from one or more injection points positioned vertically along the side of the reaction zone.

Abstract: In the introduction of fresh carbonaceous particles into a fluid-bed reaction zone at injection velocities in excess of 20 ft/sec, a shroud gas is passed through a shroud passage on the injection nozzle at a velocity in excess of about 750 ft/sec, preferably at from about 1,000 to about 5,000 ft/sec, in sufficient quantities to supply a substantial portion of the overall energy input into the reaction zone for dispersion of the fresh particles and for breaking up of any agglomerates formed upon injection of the fresh particles into the reaction zone. By accommodating the agglomerating tendencies of the fresh feed material, the high energy shroud gas effectively contributes to the prevention of defluidization of the bed. The shroud gas may be inert or may comprise a gaseous reagent that reacts with the fresh carbonaceous particles in the reaction zone. The energy supplied by the shroud gas desirably is at least about 80% of said energy input to the reaction zone.

Abstract: Method of mixing particulate materials comprising contacting a primary source and a secondary source thereof whereby resulting mixture ensues; preferably at least one of the two sources has enough motion to insure good mixing and the particulate materials may be heat treated if desired.Apparatus for such mixing comprising an inlet for a primary source, a reactor communicating therewith, a feeding means for supplying a secondary source to the reactor, and an inlet for the secondary source. Feeding means is preferably adapted to supply fluidized materials.

Abstract: In a continuous process for recovery of values from a solid carbonaceous material, the carbonaceous material is pyrolyzed in the presence of a particulate source of heat to yield a particulate carbon containing residue of pyrolysis and volatilized hydrocarbons while simultaneously the volatilized hydrocarbons are hydrogenated. The particulate source of heat is formed by oxidizing carbon in the solid residue to heat the particles. Hydrogen for hydrogenation is obtained by reacting at least a portion of the hot particulate carbon containing residue of pyrolysis with steam prior to feeding the hot particulate residue to the pyrolysis reaction zone. Steam and/or carbon dioxide can be introduced into the pyrolysis reaction zone to interact with carbon containing residue contained therein. The particulate source of heat can be introduced to the pyrolysis reaction zone over an overflow weir.

Abstract: Apparatus for conducting the flash pyrolysis of a primary material, particularly coal, and employing a secondary material, particularly hot char, as a heat source, comprising a rectangular slot for injection of a stream of particulate coal, which communicates with a substantially rectangular reactor or pyrolysis chamber. Wells are positioned on opposite sides of the pyrolysis chamber and in communication therewith, for introduction of fluidized secondary material, particularly hot char, into the pyrolysis chamber for admixture therein with and for heating the stream of primary material, such as coal. The pyrolysis chamber has a transition chamber, and a cylindrical separator chamber communicates with the transition chamber for receiving pyrolysis products. The separator chamber is provided with a tangential inlet, a solids outlet conduit positioned about 90.degree. around the circumference of the separator chamber from the tangential inlet, and a perforate gas receiver.

Abstract: A method of manufacturing a briquetted coke from fine coal comprises carbonizing the coal at a temperature of from around 600.degree. to 900.degree. C., mixing the carbonized coal with approximately 10 to 80% and preferably from 20 to 40% of fine coal well caking coal, and thereafter hot briquetting the mixture at temperatures of from around 300.degree. to 500.degree. C. A fuel for shaft furnaces preferably includes the use of the hot briquettes as the only solid fuel in the shaft furnace, and it is particularly applicable for blast furnaces.

Abstract: A process for the recovery of chemical values from waste solids, wherein shredded waste solids are intermixed with hot char and a carrier gas in turbulent flow and passed through a pyrolysis zone under turbulent conditions at a temperature ranging from about 300.degree. F. to about 2000.degree. F., with zone residence time of under 10 seconds, with subsequent segregation and recovery of volatilized organic chemical values, char and inorganic chemical values therefrom.

Abstract: Solid carbonaceous materials are pyrolyzed by introducing a low velocity stream of carbonaceous material into a cyclone reactor-separator and introducing a low velocity stream of a particulate source of heat into the cyclone reactor-separator at an angle inclined toward the path of travel of the carbonaceous material. A high velocity stream of the particulate source of heat is introduced into the cyclone reactor-separator along the inner surface of the separator to prevent carbonaceous material from caking along the walls of the separator. The velocity of the high velocity stream is at least about 50 feet per second greater than the velocity of both low velocity streams. The cyclone reactor separator induces separation of solids consisting of a particulate carbon containing solid residue of pyrolysis and particulate heat source from a vapor stream which contains hydrocarbon products of pyrolysis.

Abstract: A process for producing calcined coke agglomerates characterized by having a low reactivity to carbon dioxide. The process includes calcining green coal agglomerates at a temperature within the range of 1700.degree. F. to 1950.degree. F. (927.degree. C. to 1066.degree. C.) in a calciner. The agglomerates are exposed to a gaseous atmosphere which before cracking contains not less than 20% by volume of at least one straight chain aliphatic hydrocarbon gas containing one to four carbon atoms. The gaseous atmosphere is preheated to a temperature within the range of 200.degree. F. to 700.degree. F.(93.degree. C. to 371.degree. C.) prior to being introduced into the calciner. Carbon produced when the hydrocarbon gas is cracked, is deposited as vitreous carbon on the surfaces, in the fissures and in the pores of the agglomerates. The calcined coke aggglomerates discharged from the calciner have a reactivity to carbon dioxide of between 2% to 8%.