Abstract: A regenerating process comprises leaching a combustion ash with water so as to dissolve same and form a pregnant leach liquor containing the additive which is separated from the solid residue. The pregnant leach liquor is thereafter adjusted with a base precipitating agent so as to precipitate a compound of the additive which is then recovered by liquid solid separation. The process of the present invention is particularly useful for regenerating said recycling sulfur capturing additives used in hydrocarbon formulations which are burned as fuels, particularly, hydrocarbon in water emulsions formed from viscous hydrocarbon materials characterized by high sulfur and metals contents.

Abstract: A process for removing mineral impurities such as metal oxides from coal and shale oil structures is disclosed. The process is carried out by subjecting crushed coal or shale to a hydrocarbon fluoride leaching solution, separating the HF leach liquor from the coal or shale, washing the coal or shale with water, leaching the washed coal or shale with hydrogen chloride solution, separating the HCl leach liquor from the coal or shale, washing the coal or shale with water, and removing residual impurities from the treated coal or shale by heating under a vacuum. The process allows for the recovery of carbons and hydrocarbons of high purity from coal or shale which do not require expensive emission control equipment when combusted.

Abstract: Coke for reactor graphite is produced continuously by coking a hard pitch with a softening point (K.-S.) above 130.degree. C. and a coking residue of at least 45% by weight in a rotary pipe furnace equipped with a moving device and subsequent calcination without intermediate cooling. The temperature of the inner wall of the indirectly heated furnace ranges from about 500.degree. to about 800.degree. C. The gases and vapors formed during the coking process are guided in countercurrent flow to the pitch.

Abstract: Active form coke is made from coal by passing the coal granulate downwardly through a preheating and pyrolysis zone, a heating zone, an aftertreatment zone and a cooling zone by moving respective grate bars of grates in each zone so that a bed of granules on one grate trickles uniformly onto the next lower grate. In the preheating, heating and aftertreatment zone CO.sub.2 or steam are passed through the beds by laterally introducing the gas at one side and withdrawing the gas on the opposite side of a respective bed.

Abstract: This invention discloses processes for the treatment of coal and coal derivatives in order to remove contaminates to produce a high purity coal product. The processes generally comprise a sequential acid leaching in which a hydrofluoric acid leach is followed by a hydrochloric acid leach. The pyrite and other heavy metals from the coal are removed by physical separation, either gravity or magnetic separation. The leached coal is then treated either by a washing and drying step or by a heat treatment to remove volatile halides. The HF acid and the HCl acid leachates are recovered for regeneration of the respective leachates and are recycled for use in the leaching steps. In additional processing, the coal may be pre-treated by a mild HCl acid leach and by pre-drying or physical beneficiation of the coal feedstock.

Abstract: Chemical beneficiation of coal and other carbonaceous solids utilizing hydrofluoric acid and ammonium chloride.

Abstract: The method employs a furnace, wherein organic distillation products released from the binder and the gaseous and particulate decomposition products are burned off. Bodies, placed on the ceramic bottom plate of a truck, are introduced into the pre-heating zone of the furnace, covered with protective coverings, and heated to 200.degree.-600.degree. C. in an oxidizing medium. Thereafter, the coverings are removed in a vestibule, in an inert or slightly reducing medium, and the bodies are introduced into the calcining zone, provided with an inert or slightly reducing medium, to be further heated up to a temperature in the 1000.degree. to 1200.degree. C. range. Lastly, the bodies are cooled in a first cooling zone down to 400.degree.-450.degree. C. in an inert or slightly reducing medium, and in a second zone down to room temperature.

Abstract: A process is disclosed for removing a substantial portion of water and impurities from low rank coal and peat, whereby an improved coal or peat product (not found in nature) is obtained. The low rank coal and peat are subjected to a superheated gaseous medium, thereby substantially desorbing the moisture from the coal or peat and producing superheated gases. A substantial portion of the superheated gases produced is recycled back in contact with the coal being dried. Sufficient heat is added to the recycled gases, in response to monitoring, so that the recycled gases are maintained in a substantially superheated condition throughout. This process produces a dried, substantially purified product which retains a substantial portion of its volatile content, which has an improved heat value per unit weight, and which will not absorb substantial moisture when stored or transported. In one embodiment, the process utilizes superheated steam to initiate the drying process.

Abstract: An internally-fired vertical shaft kiln for calcining coke wherein a downwardly moving coke bed has a co-current preheat gas stream in the upper portion of the kiln and a counter-current combustion gas stream in the lower portion of the kiln. Both gases are removed at the midportion of the kiln. Combustion air is introduced to the kiln through an inclined grate at the bottom of the kiln which retains a layer of coke thereon for internal combustion. The calcined coke moves over the combusting coke layer on the grate and then through a passage to a cooling chamber where a gas stream is passed through the calcined coke for cooling. The gas stream heated in the cooling chamber can be used as the co-current gas preheat stream in the upper section of the kiln.

Abstract: A process for removing sulfur from coal comprising the steps of forming a slurry of coal, a carrier liquid, and a compound selected from the group consisting of carboxylic acid, percarboxylic acid, salts of carboxylic acid, and salts of percarboxylic acid, and any combination thereof.

Abstract: The present invention provides processes for the continuous removal of contaminants from coal to produce a clean purified fuel. The processes generally comprise producing a clean coal product having a mineral matter content of less than about 5 percent by weight from coal and coal derivatives by leaching feed coal crushed or sized to less than about 1 inch with a mixture of hydrochloric and hydrofluoric acids comprising less than about 70 weight percent HF and less than about 38 weight percent HCl at atmospheric pressure and at a temperature below the boiling point of the acid mixture.

Abstract: Pyritic sulfur is removed from coal to concentrate gas fraction collecting a gas fraction at decomposition temperatures within the range from 375.degree. to 550.degree. C. The collected fraction contains at least 60% of the total composable sulfur and not over 40% of the evolvable gas.

Abstract: A process and apparatus for desulfurizing coal which removes sulfur in the inorganic and organic form by preferentially heating the inorganic iron sulfides in coal in a flowing gas to convert some of the inorganic iron sulfides from a pyrite form FeS.sub.2 to a troilite FeS form or a pyrrhotite form Fe.sub.1-x S and release some of the sulfur as a gaseous compound. The troilite and pyrrhotite forms are convenient catalyst for removing the organic sulfur in the next step, which is to react the coal with chemical agents such as alcohol, thus removing the organic sulfur as a liquid or a gas such as H.sub.2 S. The remaining inorganic sulfur is left in the predominantly higher magnetic form of pyrrhotite and is then removed by magnetic separation techniques. Optionally, an organic flocculant may be added after the organic sulfur has been removed and before magnetic separation. The flocculant attaches non-pyrite minerals with the pyrrhotite for removal by magnetic separation to reduce the ash-forming contents.

Abstract: A method for increasing the magnetization of pyrite-containing pulverized coal comprises heating the coal in an atmosphere of inert gas, desirably nitrogen, containing 3 to 60 torr, preferably 12 to 16 torr, partial pressure of air to a temperature in the range 390.degree. to 455.degree. C., desirably 400.degree. to 410.degree. C., for a time sufficient, preferably 2 minutes to 2 hours, for converting enough pyrite to magnetite to allow separation of at least 50% by weight of the pyrite from the coal in a low-strength magnetic field. The sulfur content of coal treated in accordance with this method can be reduced by subjecting the treated coal to a low-strength magnetic field for moving at least 50% by weight of the pyrite from the coal although a smaller fraction, about 5 to 25%, of the pyrite is actually converted to magnetite.

Abstract: The sulphur emissive capability, on combustion, of coke which is formed during upgrading of sulphur-containing heavy crude oils, including oil sands bitumen, and residua, is decreased by the addition of calcium carbonate, calcium hydroxide or calcium oxide, in particulate form, to the heavy crude oil prior to coking, and uniformly dispersing the same therein. The presence of the calcium compound leads to an increased yield of liquid distillates from the coking process under the coking conditions. For calcium carbonate, the Ca:S ratio is about 1:5 to 1:1 and the coking temperature is about 400.degree. to 500.degree. C. For calcium hydroxide and calcium oxide, the Ca:S ratio is about 1:3 to 1:1 and the coking temperature is about 450.degree. to about 500.degree. C.

Abstract: A process for the removal of pyritic sulfur from shale, coal and other carbonaceous material which comprises reacting a pyritic containing solid with a acidic cerium IV salt solution.

Abstract: A process for removing sulfur and ash from coal and other carbonaceous materials involving treating an aqueous slurry of coal or other carbonaceous materials at an elevated temperature below the oxidation temperature of the coal or other carbonaceous materials in the presence of an oxidizing agent capable of reducing pyritic sulfides to a soluble state with: (A) an alkaline earth metal and/or alkali metal chloride, a catalyst comprising one or more deliquescent halogen compounds, barium chloride, potassium chloride or mixtures thereof, and one or more reducing oxides, chromate salts or mixtures thereof, and an inorganic acid, or (B) a formulation comprising one or more hypochlorites and the above-described catalyst or catalyst and acid. Sulfur is extracted as sulfate or other soluble sulfurs.

Abstract: This invention describes a chemical process for desulfurizing coal, especially adaptable to the treatment of coal-water slurries, at temperatures as low as ambient, comprising treating the coal with aqueous titanous chloride whereby hydrogen sulfide is liberated and the desulfurized coal is separated with the conversion of titanous chloride to titanium oxides.

Abstract: A method is provided for producing needle coke comprising the steps of heating green needle coke at temperatures between about 935.degree. F. and about 1,100.degree. F. for between about 10 minutes and about 24 hours, cooling the coke to below about 250.degree. F., and calcining the coke at calcination temperatures above about 2,000.degree. F.

Abstract: Disclosed herein is a method for treating raw coal with ozone in aqueous suspension to modify the surface of the coal particle and release the ash constituents thereby permitting a more thorough separation of coal from ash by conventional means. The process also provides a mixture which is easily dewatered.

Abstract: A method for removing the ash mineral matter content of coal and transporting the ash free coal from the point of ash removal to a coal use point comprising grinding run-of-mine coal to a desired particle size, mixing the coal particles with water and liquid carbon dioxide in a vessel in a swirling, fluidized state at a pressure, temperature, and for a residence time sufficient to free substantially all of the ash mineral matter from the coal and form an ash free coal/mineral matter slurry, separating the ash free coal particles from the slurry by froth floatation, drying the ash free coal particles, forming a slurry of the ash free coal particles with liquid carbon dioxide, transporting the ash free coal/liquid carbon dioxide slurry by pipeline to a coal use point, deslurrying the ash free coal/liquid carbon dioxide slurry, recovering the ash free coal particles for intended use and recycling the coal-free liquid carbon dioxide recovered from deslurrying for treating additional coal in the ash removal step.

Abstract: A one or two-step process of treating high-sulfur caking coals for desulfurization, elimination of caking tendencies and incorporation of gasification catalyst thereon prior to steam- or hydrogasification thereof, or its use as a boiler fuel. In the one step process the coal is subjected to an aqueous lime/O.sub.2 (or air) treatment under controlled conditions of time, temperature and pressure to accomplish the foregoing, whereas in the two-step process the coal is first treated with oxygen or air in dilute alkaline slurry at elevated temperature and pressure to remove the sulfur and then treated with a lime slurry, under controlled temperature conditions to incorporate the catalytic inducing lime.

Abstract: A method is provided for producing needle coke comprising the steps of heating green needle coke at temperatures between about 875.degree. F. and about 1,200.degree. F. for between about 10 minutes and about 24 hours, and, without first allowing the temperature of the coke to cool below about 250.degree. F., calcining the green needle coke at calcination temperatures above about 2,000.degree. F.

Abstract: A molded solid fuel comprises a carbonaceous fuel material, a desulfurizing agent, and K.sub.2 CO.sub.3 and is effective to emit a reduced amount of sulfur when burned.

Abstract: Pyritic sulfur, organic sulfur, and ash-forming minerals are removed from coal by a 2-stage alkaline treatment, using sodium carbonate or bicarbonate as the reagent. The first stage is an alkaline oxidation at moderate temperatures (130.degree.-150.degree. C.), and the second stage is a non-oxidizing alkaline treatment at a much higher temperature (250.degree.-330.degree. C.). The alkaline treated coal is extracted with an aqueous mineral acid, preferably hot aqueous sulfuric acid (H.sub.2 SO.sub.4) followed by washing with hot water. The resulting low-ash, low-sulfur coal can be used as a fuel in oil-firing boilers, and for similar applications where minimal-ash content is a basic requirement.

Abstract: Coking of residual oil and devolatization/partial gasification and desulfurization of solid particulate fuel are carried out in a single reactor. The particulate fuel is burned in a combustion zone in the bottom of the reactor. A bed of particulate fuel is fluidized above the combustion zone with gases rising from the combustion zone. The fluidized bed is maintained at a temperature which cokes the residual oil and volatizes the particulate fuel. A high temperature, low velocity zone is maintained between the combustion zone and the fluidized bed for calcination and desulfurization of the solid fuel.

Abstract: High sulfur content carbonaceous material, such as coal is desulfurized by continuous fluidized suspension (20) in a reactor (18) with chlorine gas, inert dechlorinating gas and hydrogen gas. A source of chlorine gas (30), a source (32) of inert gas and a source (34) of hydrogen gas are connected to the bottom inlet (24) through a manifold (28) and a heater (26). A flow controller (42) operates servos (36, 38, 40) in a manner to continuously and sequentially suspend coal in the three gases. The sulfur content is reduced at least 50% by the treatment.

Abstract: A process for the removal of divalent organic and inorganic sulfur compounds from coal and other carbonaceous material. A slurry of pulverized carbonaceous material is contacted with an electrophilic oxidant which selectively oxidizes the divalent organic and inorganic compounds to trivalent and tetravalent compounds. The carbonaceous material is then contacted with a molten caustic which dissolves the oxidized sulfur compounds away from the hydrocarbon matrix.

Abstract: A process for removal of sulfur from fossil fuels, such as coal, lignite, peat and fuel oil. The process includes the oxidative treatment of the fuel at or about ambient temperature, followed by a wash with a dilute basic aqueous solution of a basic compound of alkali metal or alkaline earth metal at or about ambient temperature. Upon burning of the fuel, a large amount of the sulfur is trapped as a sulfate in the resulting ash rather than as a gas in the effluent.

Abstract: Coal is processed sequentially over a range of temperatures up to a maximum of 750.degree. F. and preferably considerably less to obtain a clean burning coke, refinable petroleum and bitumen products, fertilizer minerals, combustible gases and water; the process is capable of producing a highly porous, easily crushed coke substantially free of pollutants and almost entirely depleted of oil so that it is hygroscopic and easily transformed to a pipeline slurry. The process is not one of destructive distillation but neither is atmospheric air employed as a combustion oxidant or reactant in the system; the process is preferably conducted under reflux conditions in a closed vessel and in such a way that the heat input is complemental substantially to the thermo-absorption spectrum of the coal.

Abstract: Green petroleum coke is partly devolatilized by transporting horizontally in static bed form through a furnace over a series of air box zones including a minority of zones adjacent the input end of the furnace and a majority remote from the input end and further devolatilized by soaking in a shaft furnace until at least most of the residual volatiles are driven off. From the shaft furnace the devolatilized coke is water quenched and steam produced in the quencher is mixed with downdrafted gases from said furnace to cool the same and prevent premature combustion.

Abstract: A desulfurization process is described which consists of heating an organic hydrocarbon like coal or bitumen in a stream of a gaseous or liquid trapping material for hydrogen sulfide (H.sub.2 S). The organic sulfur in the hydrocarbon decomposes and releases H.sub.2 S which reacts with the trapping material to form a metastable sulfur compound. The resulting gaseous or liquid stream is recovered and decomposed in a subsequent step to form H.sub.2 S and to the original trapping material. The trapping material is recovered and recirculated into the reactor. Ethylene, propylene and other olefins, as well as aldehydes and ketones are found to be excellent trapping materials.

Abstract: In the extraction of coal the liquid coal extract is filtered using a filter aid produced by washing the filter cake with a low viscosity, high boiling point, low vapor pressure ester and then calcining the cake to remove the wash solvent and other combustible constituents from the cake.

Abstract: A method for desulfurization, denitrification, and oxidation, of carbonaceous fuels including a two stage oxidation technique. The carbonaceous fuel, containing ash, along with an oxygen-containing gas is introduced into a first stage partial oxidation unit containing a molten ash slag maintained at a temperature of about 2200.degree.-2600.degree. F. A flux may also be introduced into the first stage partial oxidation unit for the purpose of increasing the basicity and maintaining the viscosity of the molten ash slag at a value no greater than about 10 poise. The carbonaceous fuel is gasified, and sulfur is chemically bound and captured in the molten ash slag. Since the first stage is operated in a gasification mode (reducing atmosphere), essentially all of the nitrogen in the fuel is converted to diatomic nitrogen, which results in low nitrogen oxide emissions upon final combustion.

Abstract: Compacted carbonaceous shapes are produced by mixing a particulate carbonaceous material with a binder, forming green shapes from the mixture, and heating the green shapes by induction heating or microwave heating or a combination thereof. The process is particularly adapted for making formcoke.

Abstract: Combustion gas such as air, oxygen-enriched air or oxygen is introduced at an intermediate level in a vertical shaft kiln for the calcining of petroleum coke using a plurality of radially disposed combustion gas injectors. The injectors include means for circulating coolant around the periphery of the injector so that common metals may be used in the high temperature (above 2000.degree. F.) environment of the shaft kiln.

Abstract: Combustion gas such as air, oxygen-enriched air or oxygen is introduced to a calcining zone at an intermediate level in a vertical shaft kiln for the calcining of petroleum coke utilizing a plurality of radially disposed combustion gas injectors and at least one vertically disposed injector located within the shaft kiln and extending into the calcining zone. The injector includes means for circulating coolant around the periphery of the injector so that common metals may be used in the high temperature (above 2000.degree. F.) environment of the shaft kiln. The vertical combustion gas injector may extend from the top of the calcining chamber to the calcining zone or from the bottom of the calcining chamber to the calcining zone. When the vertical combustion gas injector extends vertically upwardly from the bottom of the calcining chamber, means for introducing recycle gas to the calcining chamber may be incorporated into the vertical combustion gas injector.

Abstract: The production of hydrogenated tar and distillates from coal which is passed through successive condensing, hydrogenation, desulfurization and cooling zones of a dense bed while a flue gas is discharged into the lower portion of the desulfurization zone in admixture with steam and hydrogen for countercurrent flow contact with the coal and coke solids. The gases evolved from the desulfurization zone are passed into countercurrent contact with the coal in the preceding hydrogenation zone where the high boiling coal tar fractions evolved from the coal are hydrogenated and pyrolyzed. The total effluent from the hydrogenation zone is then passed into countercurrent contact with the coal in the condensing zone, preheating the coal by direct contact and initiating the pyrolysis of the coal. The preferred method is practiced in a vertical kiln through which the coal is passed as a dense, compact gravitating bed of solids.

Abstract: Delayed coke is desulfurized by first contacting the coke with an active sulfur-bearing gas at a temperature high enough to produce a reaction between the sulfur in the coke and the active sulfur in the gas, and then holding the coke in contact with the gas at said high temperature for approximately one hour. An alternative process provides for desulfurization of delayed coke by modifying the second step of the prior process to dilute or replace the sulfur-bearing gas with an inert gas. In a third alternative, the foregoing process is further modified by lowering the temperature during the second or holding step to maintain the reaction between the sulfur-bearing gas and the coke.

Abstract: A drain and sampling valve assembly for a fluidized bed reactor in which a pipe extends from the fluidized bed supporting structure to a location externally of said reactor. A valve seat is supported by said supporting structure and a valve stem is disposed in the pipe and extends for the length of the pipe and has a valve head mounted at one end of the stem for cooperating with the valve seat. A mechanical actuator assembly is provided externally of said reactor for selectively moving the stem relative to the pipe and the movement of the valve head relative to the valve seat to control the flow of material from the fluidized bed into the pipe. A discharge pipe and a sampling valve cooperate with the other end of the first mentioned pipe for selectively controlling the discharge of material from said latter pipe for permitting samples to be taken.

Abstract: Improved process and system for reducing the amounts of hydrogen sulfide emitted during pyrolysis of oil shale. At the elevated temperatures of oil shale pyrolysis, iron pyrite is converted to hydrogen sulfide which is emitted with the product gases and oils. Reduction in hydrogen sulfide emissions is accomplished by treating the oil shale with ultraviolet radiation of a particular wave length prior to pyrolysis in the presence of oxygen to selectively oxidize the pyritic sulfur to sulfate sulfur. The treated oil shale is then retorted at conventional temperatures. The sulfate sulfur does not decompose or otherwise convert to hydrogen sulfide at these temperatures. The sulfate sulfur remains in the spent shale residue and is discarded as waste to thereby effectively reduce the amount of sulfur emitted as hydrogen sulfide in the pyrolysis product gases.

Abstract: A method for desulfurization and oxidation of carbonaceous fuels including a two stage oxidation technique. The carbonaceous fuel, along with an oxygen-containing gas is introduced into a first stage partial oxidation unit containing molten slag maintained at a temperature of about 2200.degree.-2600.degree. F. A flux may also be introduced into the first stage partial oxidation unit for the purpose of maintaining the viscosity of the molten slag at a value no greater than about 10 poise. The carbonaceous fuel is gasified, and sulfur is chemically bound and captured in the molten slag. The combustible gas derived from partial oxidation and gasification is directed along a substantially horizontal path to a second stage oxidation unit for final combustion. The sulfur-containing slag is removed to a water-sealed quench system for disposal.

Abstract: A method of desulfurization is described in which high sulfur coals are desulfurized by low temperature chlorinolysis (12) of coal in liquid media, preferably water, followed by hydrodesulfurization (26) at a temperature above 500.degree. C. The coals are desulfurized to an extent of up to 90% by weight and simultaneously dechlorinated to a chlorine content below 0.1% by weight. The product coals have lower volatiles loss, lower oxygen and nitrogen content and higher fixed carbon than raw coals treated with hydrogen under the same conditions.Heating the chlorinated coal to a temperature above 500.degree. C. in inert gas such as nitrogen results in significantly less desulfurization.

Abstract: A process for reducing the sulfur and ash content of coal and the like by treatment in an aqueous slurry with ultrasound followed by subsequent separating steps.

Abstract: Petroleum coke is processed to reduce the sulfur content. Ground coke is contacted with hot hydrogen, under pressurized conditions, for a residence time of about 2 to 60 seconds. The desulfurized coke is suitable for metallurgical or electrode uses.

Abstract: A process for producing a distillable hydrocarbonaceous stream, fuel gases and blast furnace grade coke from a heavy, high sulfur, crude oil by producing delayed coke from at least a portion of the crude oil; crushing at least a portion of the coke to provide a finely divided coke feedstock to a briquetting operation where the finely divided coke is briquetted using crude oil or topped crude oil as a binder to produce briquettes of a size from about 3/4 inch to about 3 inches with the resulting briquettes being passed to a high temperature vertical calciner where the solids are desulfurized to produce a strong blast furnace grade coke. The distillable stream and fuel gas stream are recovered from the delayed coking operation, the vertical calciner and optionally a crude oil topping operation. In some instances coke particles in the size range from about 3/4 inch to about 3 inches may be passed directly to the calciner without crushing and briquetting.

Abstract: Arsenic is removed from green shale oil coke of high arsenic content by calcining the coke at 1500.degree. F. to 3000.degree. F. for 0.1 hr to 4 hr. The arsenic content is reduced from above about 150 to 300 ppm to below about 100 ppm, thereby making the coke suitable for use as a fuel, in electrodes for producing aluminum, or in steel making.

Abstract: Solid carbonaceous material, especially coal or coal char, is desulfurized by treatment with a limited amount of hydrogen to convert the organic sulfur to sulfide sulfur at an elevated temperature. The thusly formed sulfide sulfur is then removed from the solid carbonaceous material by steam treatment or other means.

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: In a formed coke process of the type in which carbonization and calcination of coal is carried out prior to briquetting, the hot calcined char is cooled by means of a hydrogen-rich gas at superatmospheric pressure so as to effect concurrent cooling and desulfurization of the char. High sulfur coal containing 1.5 to 4 wt. % sulfur can be used while obtaining a char and a formed coke product with a sulfur content of 0.8 wt. % or less. The cooling can be done in two stages: (1) a first stage in which sulfur removal and cooling to a temperature not lower than about 800.degree. F. are accomplished with a hydrogen-rich gas, and (2) a second stage in which further cooling to about 200.degree. F. or less is accomplished with an inert gas.