Abstract: In a method for the production of a fertilizer from the sulfur and ammonia content in a feed gas, including steps of (a) combustion of the H2S-rich gas in air to convert H2S to SO2, (b) formation of ammonium hydrogen sulfite (AHS) by absorption of SO2 and NH3 in water, and (c) reaction of the AHS from step (b) with H2S and NH3 to form an aqueous solution of ammonium thiosulfate (ATS), reaction (a) is carried out in a catalytic reactor as a selective oxidation of the H2S content to SO2 over a selective catalyst having one or more metal oxides, in which the metal is selected from the group of V, W, Ce, Mo, Fe, Ca and Mg, and one or more supports taken from the group of Al2O3, SiO2, SiC and TiO2, optionally in the presence of other elements in a concentration below 1 wt %.

Abstract: A combustible gas from carbon black production is utilized in a gas engine by adding an oxygen-containing gas to the combustible gas, passing said mixed gas over a selective catalyst, which is active for oxidizing H2S to SO2 but substantially inactive for oxidation of CO, H2 and other hydrocarbons with less than 4 C-atoms, passing the converted gas through an SO2 removal step, and passing the cleaned gas to a gas engine or to an energy recovery boiler. This way, the tail gas from carbon black production, which is normally combusted in a CO boiler or incinerated, can be utilized to good effect.

Abstract: The invention is a method and a sulfuric acid plant design for reduction of start-up SO2, SO3 and H2SO4 emissions in sulfuric acid production, in which SO2 is converted to SO3 in n successive catalyst beds, where n is an integer >1. The final catalytic beds are used as absorbents for SO2 to SO3 during the start-up procedure, and one or more of the m beds downstream the first bed are purged, either separately or simultaneously, with hot gas, where m is an integer >1 and m<n, during the previous shut-down. Also, one separate purge with hot gas is used on the final bed.

Abstract: In a process for the removal of soot from a sulfurous gas stream, a process gas containing O2 and more than 500 ppm SO2 and/or SO3 together with soot is brought into contact with a VK type catalyst in a reactor, said catalyst comprising vanadium pentoxide (V2O5), sulfur in the form of sulfate, pyrosulfate, tri- or tetrasulfate and one or more alkali metals, such as Na, K, Rb or Cs, on a porous carrier, preferably a silicon dioxide carrier.

Abstract: A combustible gas from carbon black production is utilized in a gas engine by adding an oxygen-containing gas to the combustible gas, passing said mixed gas over a selective catalyst, which is active for oxidizing H2S to SO2 but substantially inactive for oxidation of CO, H2 and other hydrocarbons with less than 4 C-atoms, passing the converted gas through an SO2 removal step, and passing the cleaned gas to a gas engine or to an energy recovery boiler. This way, the tail gas from carbon black production, which is normally combusted in a CO boiler or incinerated, can be utilized to good effect.

Abstract: The invention is a method and a sulfuric acid plant design for reduction of start-up SO2, SO3 and H2SO4 emissions in sulfuric acid production, in which SO2 is converted to SO3 in n successive catalyst beds, where n is an integer >1. The final catalytic beds are used as absorbents for SO2 to SO3 during the start-up procedure, and one or more of the m beds downstream the first bed are purged, either separately or simultaneously, with hot gas, where m is an integer >1 and m<n, during the previous shut-down. Also, one separate purge with hot gas is used on the final bed.

Abstract: In a process for the removal of soot from a sulfurous gas stream, a process gas containing O2 and more than 500 ppm SO2 and/or SO3 together with soot is brought into contact with a VK type catalyst in a reactor, said catalyst comprising vanadium pentoxide (V2O5), sulfur in the form of sulfate, pyrosulfate, tri- or tetrasulfate and one or more alkali metals, such as Na, K, Rb or Cs, on a porous carrier, preferably a silicon dioxide carrier.

Abstract: A process for removal of SO2 in off-gases having a temperature of 30-150° C. and containing 0.001-1 vol % SO2 in which the SO2 is oxidised to H2 SO4 by spraying an aqueous solution of H2O2 into the off-gas upstream of an aerosol filter removing the produced sulphuric acid from the off-gas.

Abstract: A process of producing sulfuric acid from feed gases containing 0.1-30% SO2. The process produces concentrated sulfuric acid from a feed gas containing 0.1 vol % to 30 vol % SO2, in particular a strong feed gas containing 6 vol % to 30 vol % SO2, that enables the gas entering the final wet condensing stage to have an acid dew point of below 260° C., while at the same time achieving current requirements of acid mist emissions of about 20 ppmv without resorting to substantial air dilution of the strong feed gas.

Abstract: A process for production of sulphuric acid comprising condensing sulphuric acid vapour from a gas mixture containing 0.01 to 10 vol. % of H2SO4 vapour calculated at complete hydration of SO3 in the gas to H2SO4 and 0 to 50 vol. % of water vapour by cooling of the gas in a sulphuric acid tower, wherein a stream containing NH3 is added upstream of the tower in an amount corresponding to 0.01-100 ppm NH3 by vol. in the gas stream at the entry of the tower.

Abstract: A process for continuous production of ammonium thiosulphate, (NH4)2S2O3 (ATS) from NH3, H2S and SO2 is disclosed. A first feed stream comprising H2O, H2S and NH3 with a molar H2S:NH3 ratio <0.4 is partially condensed to form a condensate. The condensate is contacted with a third feed gas comprising H2S and the gas stream comprising NH3 and H2S is passed to a mixing device where the gas stream is dissolved in water drained off from an aerosol filter. A second feed gas stream comprising approximately ? mole SO2 per mole of NH3 contained in the first feed stream is passed to a SO2 absorber. The aqueous solution produced in mixing device is contacted with the SO2 absorber.

Abstract: A process for the production of sulphuric acid from a sulphur dioxide containing feed gas with concentration of SO2 fluctuating between 0 and 100 mole % SO2 comprising the steps of contacting the feed gas with an aqueous solution comprising 0–50% by weight H2SO4 at a temperature between the freezing point of said aqueous solution and 80° C.; and during the contact of the feed gas with the aqueous solution absorbing at least a part of SO2 in the feed gas in the aqueous solution or desorbing at least a part of SO2 from the aqueous solution, wherein the at least a part of SO2 is desorbed by stripping the aqueous solution with the feed gas and passing at least part of the thus treated feed gas to a sulphuric acid plant.

Abstract: A process for continuous production of ammonium thiosulphate, (NH4)2S2O3 (ATS) from NH3, H2S and SO2 comprising steps of:

Abstract: A process for production of ammonium thiosulphate (ATS) from H2S, NH3 and SO2, comprising producing ATS in a first absorption step by treating a first stream comprising H2S and NH3 with more than 0.3 mole H2S per mole NH3 with a solution containing ATS and ammonium sulphite, said solution being produced, in a second absorption step, by treating part of the solution from the first absorption step with a second gas stream gas stream comprising SO2. The second gas stream is obtained by combusting the H2S-containing off gas from the first absorption step supplemented with H2S-containing gas imported from other sources and/or by importing SO2-containing off gas streams from other souses. The content of NH3 in the off gas from the second absorber may be decreased by adding the equivalent amount of SO2 to the off gas upstream of an aerosol filter removing the NH3 and SO2 as a solution of NH4HSO3, which is fed to the first or second absorber, while the off gas from the filter is passed to the atmosphere.