Abstract: A feed stream of digester gas from an anaerobic process is compressed to a predetermined pressure of about 300 p.s.i.g. and fed into an absorber at that pressure. Carbon dioxide and hydrogen sulfide impurities of this feed stream are absorbed in the absorber by counterflowing water. Water from the absorber may be fed back to an activated sludge sewage treatment facility where the hydrogen sulfide is oxidized and the carbon dioxide released. As an alternative to the absorber, hydrogen sulfide is oxidized in an iron sponge reaction. Alternately, these contaminants are stripped with air and vented. Treated gas from the absorber, essentially methane, is either compressed for introduction into storage tanks, or dried and used as pipeline gas. In the dryer, adsorbed moisture is removed by air, followed by a purge with treated gas.

Abstract: A process for the catalytic incineration of residual gases containing a low content of H.sub.2 S and/or SO.sub.2, organic compounds of sulfur such as COS, CS.sub.2, mercaptans and possibly vapor and/or vesicular sulfur, comprising a hydrogenation stage which transforms all the sulfur compounds into H.sub.2 S followed by a catalytic oxidation stage to transform H.sub.2 S into SO.sub.2.The catalyst used in the oxidation stage consists in a porous support, having a surface area of at least 5 m.sup.2 /g and containing, by weight, 50 to 100% of a product selected from the group comprising titanium or zirconium oxides, silica and zeolites, and 50 to 0% alumina, to which is associated one or several compounds of metals belonging to the group formed by Cu, Ag, Zn, Cd, Y, Lanthanides, V, Cr, Mo, W, Mn, Fe, Co, Rh, Ir, Ni, Pd, Pt, Sn and Bi. The use of such an oxidation catalyst leads to a practically quantitative yield of conversion of H.sub.2 S into SO.sub.

Abstract: A method of preventing sludge deposition in the treatment of geothermal steam condensate with iron catalyzed/hydrogen peroxide by carrying out the treatment in the presence of an inorganic polyphosphate.

Abstract: There is provided a process for the adsorption and catalytic decomposition of foul-smelling intestinal gases, particularly mercaptans, wherein the intestinal gases are passed through a highly specific adsorbent which, out of a mixture of water vapor, methanol, carbon monoxide and carbon dioxide and various sulfur-containing gases, particularly mercaptan-containing gases, catalytically decomposes and adsorbs only the sulfur and mercaptan compounds and optionally desorbs the non-smelling fractions. An absorbent for use in the method is characterized in that it contains an inert, highly porous solid having a specific surface according to BET of from 900 to 1800 m.sup.2 /g or pyrogenic silicon dioxide having a surface of from 50 to 500 m.sup.2 /g, the specific surfaces having been determined by argon adsorption at -196.degree. C., which are covered over their surface with from 0.1 to 5% by weight of aluminium, zinc, chromium or iron, based on the weight of the solid having a specific surface of 1000 m.sup.

Abstract: Hydrogen sulfide is selectively oxidized in a gas stream containing at least 20 mol percent a carbon dioxide using an iron catalyst, preferably Fe.sub.2 O.sub.3 supported on a ceramic honeycomb support.

Abstract: A process for removing hydrogen sulfide from geothermal steam utilizes iron oxide supported by a carrier resistant to deterioration by the geothermal steam. The process includes the addition of an oxygen-containing gas to the geothermal steam before contacting the steam with the iron oxide at a temperature of at least about 300.degree. F. The amount of oxygen added to the geothermal steam is sufficient to make the molar ratio of oxygen-to-hydrogen sulfide in the steam to be at least about 10.

Abstract: Hydrogen sulfide is removed from a fluid stream by contacting the fluid stream which contains hydrogen sulfide with an absorbing composition comprising zinc, titanium and at least one promoter selected from the group consisting of vanadium, chromium, manganese, iron, cobalt, nickel, molybdenum, rhenium, and compounds thereof. If organic sulfur compounds are present in the fluid stream, the absorbing composition acts as a hydrodesulfurization catalyst to convert the sulfur in the organic sulfur compounds to hydrogen sulfide which is subsequently removed from the fluid stream by the absorbing composition. If olefin contaminants are present in the fluid stream, the absorbing composition acts as hydrogenation catalyst to hydrogenate the olefin contaminants to paraffins.

Abstract: Substantially dry iron oxide particles having a high surface area, a high kinetic "K" value and composed of a crystalline phase of Fe.sub.3 O.sub.4 together with an amorphous Fe.sub.2 O.sub.3 moiety or portion and having a surface area of at least 4 m.sup.2 /.sub.g are useful for scavenging hydrogen sulfide from other gases containing it. A cartridge type device is provided containing such particles intermixed with inert particulate matter, e.g. sand, useful as a means for scavenging hydrogen sulfide from such other gases.

Abstract: Acid gases are removed from waste gases by contacting said gases with an orbent which is a direct reaction product a mixture of red mud and an alkaline earth metal hydroxide or aluminum oxide.

Abstract: Iron oxide particles having a high surface area, a high kinetic K value and composed substantially of amorphous Fe.sub.2 O.sub.3 and crystalline Fe.sub.2 O.sub.3 are drilling mud additives suitable for scavenging hydrogen sulfide. Such particles do not adversely affect the rheological properties of the mud and when reacted with hydrogen sulfide form reaction products which are acid stable. Upon completion of drilling, the drilling mud containing these iron oxide particles and their reaction products with H.sub.2 S may be left in place between the inner casing and the formation wall or the outer casing as a packer fluid.

Abstract: This invention relates to a process for the removal of sulfur compounds from a gas stream. More specifically, this invention relates to an improvement in the iron oxide method of sulfur removal from a gas stream through the use of hydrogen peroxide.

Abstract: A process for purifying a gas containing hydrogen sulfide, wherein said gas is admixed with oxygen and contacted with a carbon mass of specific surface higher than 50 m2/g and containing at least one oxide and/or sulfate of iron and/or copper, at a temperature from 20.degree. to 170.degree. C., the operating conditions being so selected as to avoid a substantial oxidation of said mass and said mass being periodically regenerated by heating to 200.degree.-300.degree. C. in the presence of oxygen, the regenerating conditions being such as to avoid a substantial oxidation of the carbon mass.

Abstract: A deoxidizer comprises ferrous carbonate having a specific surface area of at least 20 m.sup.2 /g. The ferrous carbonate can be combined with a mixture of a reduced iron powder and a metal halide; or an alkli metal hydroxide and/or an alkline earth metal hydroxide or calcium oxide and/or ettringite. The deoxidizer is used for the deoxidation of a package so as to substitute oxygen by carbon dioxide.

Abstract: A reducing gas, such as a synthetic fuel gas, produced by gasification of a fossil fuel, containing ammonia or both ammonia and hydrogen sulfide, is purified by passing the reducing gas at first, through a first removing agent of iron or nickel system when the hydrogen sulfide is contained, and then through a second removing agent of iron or nickel system, both at elevated temperatures. For example, when the reducing gas contains both ammonia and hydrogen sulfide, the gas is passed through the first removing agent at a temperature of 450.degree.-700.degree. C. to remove substantially all of the hydrogen sulfide and then is passed through the second removing agent at a temperature of greater than 700.degree. C., preferably up to 900.degree. C., to remove substantially all of the ammonia contained in the gas. Not only a remarkable effect upon prevention of environmental pollution but also a great improvement of energy efficiency, as compared with the conventional process, can be obtained.

Abstract: A refining process of a hot gas such as coal gas containing hydrogen sulfide and ammonia comprises steps of contacting the hot gas with a first catalyst comprising iron oxide to remove hydrogen sulfide, and then contacting the hot gas with a second catalyst comprising reduced iron made by reducing iron oxide prior to introducing the hot gas into the catalyst to remove ammonia. The refining process further includes steps of temperature adjustment of the gas directing to the first and second catalyst and the removal of hydrogen sulfide remaining in the hot gas after the removal of the ammonia with a third catalyst comprising iron oxide.

Abstract: A method for removing sulfurous gases such as H.sub.2 S and COS from a fuel gas is disclosed wherein limestone particulates containing iron sulfide provide catalytic absorption of the H.sub.2 S and COS by the limestone. The method is effective at temperatures of 400.degree. C. to 700.degree. C. in particular.

Abstract: A process for scavenging hydrogen sulfide from hydrocarbon gases utilizes iron oxide particles of unique chemical and physical properties. These particles have large surface area, and are comprised substantially of amorphous Fe.sub.2 O.sub.3 containing a crystalline phase of Fe.sub.2 O.sub.3, Fe.sub.3 O.sub.4 and combinations thereof. In scavenging hydrogen sulfide, the iron oxide particles are suspended in a liquid which enters into intimate mixing contact with hydrocarbon gases; the hydrogen sulfide is reacted at an exceptional rate and only acid-stable reaction products are formed. Thereafter, the sweetened hydrocarbon gases are collected.

Abstract: Iron rich dusts created during steelmaking, as in the basic oxygen and open hearth processes, are useful for scavenging hydrogen sulfide. For example, basic oxygen furnace dusts, which are in more abundant supply, are found to consist of fine, nearly spherical particles of iron oxide whose crystalline composition comprises Fe.sub.3 O.sub.4 (major portion) and Fe.sub.2 O.sub.3 (minor portion) as seen by X-ray diffraction. Their great surface area makes them highly reactive to hydrogen sulfide gas. Their reaction yields unexpected products, namely, free sulfur and iron hydroxides. According to the present invention such iron rich dusts are used in water slurries through which sour hydrocarbon gas is bubbled, and in water based drilling muds to scavenge hydrogen sulfide encountered in well drilling.

Abstract: Removal of hydrogen sulfide from gases using iron oxide-containing solids is improved by introducing a liquid containing a primary or secondary amine into the iron oxide-containing solids.

Abstract: A high temperature, high pressure raw coal gas containing hydrogen sulfide, ammonia, and tarry matter, is purified by contacting the raw coal gas with solid particles thereby cooling the raw coal gas to a temperature suitable for hydrogen sulfide removal and at the same time depositing the tarry matter onto the solid particles by condensation to recover the tarry matter from the raw coal gas, removing the hydrogen sulfide from the cooled and substantially tar-free coal gas, expanding the raw coal gas to a pressure suitable for ammonia decomposition, heating the expanded raw coal gas to a temperature suitable for ammonia decomposition by heat obtained by combusting the recovered tarry matter on the solid particles, thereby regenerating the solid particles for reuse, and then decomposing ammonia in the raw coal gas, thereby removing ammonia therefrom.

Abstract: Organic refuse is pyrolyzed to form disposable solids and gas. The gas is washed at a temperature well above 100.degree. C. with wash oil, which is recirculated. Spent wash oil is pyrolyzed with contaminants and further organic refuse. The washed gas is filtered through sorption means to remove acid and or other noxious gases therefrom before being cooled well below 100.degree. C. to condense water vapor and other constituents having boiling points within the range of from, e.g., 75.degree. to 150.degree. C. After separating the resulting condensate, thus-purified combustion gas is used, e.g., as a fuel source for the organic-refuse pyrolysis.

Abstract: Pulverent solid sorption agent is injected into and, optionally, admixed with a stream of noxious-contaminant-containing gas and then separated from such gas. The solid sorption agent comprises an alkali-metal and/or alkaline-earth-metal compound and advantageously contains iron-III-oxide; such agent is preferably in the form of dust developed during production of iron or steel.

Abstract: Sulfur and sulfur compounds contained in a gas are oxidized in contact with a catalyst comprising vanadium oxide, iron oxide and alumina, said catalyst having a surface higher than 30 m.sup.2 /g and being obtained by impregnation of aluminum with soluble vanadium and iron compounds.

Abstract: A process for the purification of gas, which is generated in pressure gasification of coal, which uses a wash oil, especially tar oil, as the washing liquid to avoid clogging of the washing apparatus by tars and tar compounds which precipitate out of the washing liquid when water or aqueous solutions are employed as the washing liquid. The wash oil is preferably used in the circulation, from which solids and tars are continuously removed, and is then fed into the pressure reactor again. The wash oil circulation is continually regenerated through distillation, and the residues are fed into the pressure reactor. Heat is constantly extracted from the gas before or during the washing in a heat exchange process, making it possible to keep the heat loss extremely low and to create optimum temperature at every point of the total cycle by appropriate extraction or addition of heat.

Abstract: An effective oxygen-consuming composition for packages, containers, or other closed spaces, especially containing an article susceptible to oxidative deterioration, comprises a dithionite for reacting with oxygen, sufficient alkaline material to at least partially neutralize sulfur dioxide released as a by-product of the oxygen consuming reaction, and porous filler particles in sufficient amount to promote contact with the ambient atmosphere, all in homogeneous mixture.

Abstract: Hydrogen sulfide is effectively removed from hot gaseous mixtures useful for industrial purposes by employing a solid absorbent consisting of silica-supported iron oxide in pellet form.