The present invention relates to a process for decomposing calcium sulfate (CaSO.sub.4) present in phosphogypsum (PG), comprising the following steps: a) providing a reactor containing phosphogypsum (PG) and a solid source of carbon (C), b) reacting a flow of dioxygen (Oz) with the source of carbon (C) so as to generate carbon oxide (CO), c) reacting carbon oxide (CO) obtained in step a) with calcium sulfate (CaSO.sub.4) of the phosphogypsum to produce calcium oxide (CaO) and sulfoxide (SO.sub.2) according to the following reaction: CaSO.sub.4+CO.fwdarw.CaO+SO.sub.2+CO.sub.2 wherein the mass ratio C/PG is between 0.2 and DA, and the mass ratio 15 O.sub.2/PG is between 0.5 and 1.5.

The present disclosure describes a hydrogen sulfide decomposition process for converting hydrogen sulfide into hydrogen gas and sulfur dioxide. Such a process can significantly increase the amount of available hydrogen gas. In fact, if each Claus unit in the U.S. creating elemental sulfur in traditional systems were replaced by this hydrogen sulfide decomposition process, 1.83 million metric tons of hydrogen gas could be produced. This represents about 20% of the annual hydrogen produced in the U.S. for any purpose, recovered and available for reuse. Additionally, if desired, the sulfur dioxide can be further processed to form sulfuric acid.

A process for recovering sulfur from a sour gas is provided. The process includes the steps of: providing the sour gas to a membrane separation unit having a carbon dioxide-selective membrane that comprises a perfluoropolymer, wherein the sour gas comprises carbon dioxide and at least 1 mol % hydrogen sulfide; separating the sour gas using the carbon dioxide-selective membrane in the membrane separation stage to obtain hydrogen sulfide-enriched gas and hydrogen sulfide-stripped gas, wherein the hydrogen sulfide-enriched gas has a hydrogen sulfide concentration of at least 20 mol %, and wherein the hydrogen sulfide-stripped gas comprises carbon dioxide; and processing the hydrogen sulfide-enriched gas in a sulfur recovery unit to obtain sulfur.

The present invention relates to a method and a system for catalytic oxidation of a lean H.sub.2S stream. More specifically, the invention concerns a novel way of removing sulfur dioxide (SO.sub.2) formed by catalytic oxidation of hydrogen sulfide (H.sub.2S) with the purpose of removing H.sub.2S from a gas. This catalytic oxidation of H.sub.2S yields sulfur dioxide (SO.sub.2) through the use of known catalysts, so-called SMC catalysts.

Sulfur trioxide is produced from a feed stream comprising sulfur-containing compounds and dissolved metals, such as alkali metals, in a plant comprising an incineration furnace, a waste heat boiler, a dilution air heater, a dust removal absorber and an SO.sub.2 converter. The plant may further comprise a sulfuric acid condenser for the production of sulfuric acid.

A bulk three-dimensional (3-D) catalyst and methods of making and use are described herein. The bulk three-dimensional (3-D) catalyst is formed from a catalytically active metal or metal alloy and has a sulfurized or oxidized outer surface.

A bulk three-dimensional (3-D) catalyst and methods of making and use are described herein. The bulk three-dimensional (3-D) catalyst is formed from a catalytically active metal or metal alloy and has a sulfurized or oxidized outer surface.

A plant for the production of sulfur trioxide from a feed stream containing sulfur-containing compounds and dissolved metals and alkali metals by a process, which involves gas quenching, comprises an incineration furnace, a mixing device and/or a dilution air heater, a dust removal device and an SO.sub.2 converter. The plant may further comprise a condenser for the purpose of producing sulfuric acid.

The present invention discloses a resource recovery method and a resource recovery system of desulfurized ash. The resource recovery method comprises: washing desulfurized ash with water, and performing solid-liquid separation to obtain solid residues rich in calcium sulfite and calcium sulfate and a solution rich in calcium hydroxide; preparing the solution into desulfurized slurry; and roasting the solid residues under the action of a reducing agent to obtain flue gas rich in sulfur dioxide and residues rich in calcium oxide. Therefore, the recovery of sulfur and calcium in the desulfurized ash is realized, and no solid waste, liquid waste, gas waste, etc. are produced in the process.

A process for recovering sulfur in a sulfur recovery unit comprising the steps of reacting hydrogen sulfide and oxygen in the reaction furnace at a minimum reaction temperature to produce a reaction effluent; reducing the temperature of the reaction effluent from the minimum reaction temperature to a boiler section outlet temperature to produce a cooled effluent, the cooled effluent comprises hydrogen sulfide, sulfur dioxide, and sulfur-containing contaminants; reacting the hydrogen sulfide, sulfur dioxide, and sulfur-containing contaminants in the catalytic extension to produce a boiler catalytic effluent; reducing the boiler catalytic effluent temperature such that the elemental sulfur condenses to form liquid sulfur and a gases stream; reacting the hydrogen sulfide and sulfur-containing contaminants with the oxygen to produce an oxidizer outlet stream comprises sulfur dioxide; and separating the sulfur dioxide in the scrubbing unit to produce a recycle stream and an effluent gases, the recycle stream comprises sulfur dioxide.