Sulfur oxide separation

The practical problems He ia the separatioa of the chlorine from the hydrogea chloride and nitrous gases. The dilute nitric acid must be reconcentrated and corrosion problems are severe. Suggested improvements iaclude oxidation of concentrated solutions of chlorides, eg, LiCl, by nitrates, followed by separation of chlorine from nitrosyl chloride by distillation at 135°C, or oxidation by a mixture of nitric and sulfuric acids, separating the... 

The hrst working lead cell, manufactured in 1859 by a French scientist, Gaston Plante, consisted of two lead plates separated by a strip of cloth, coiled, and inserted into a jar with sulfuric acid. A surface layer of lead dioxide was produced by electrochemical reactions in the first charge cycle. Later developments led to electrodes made by pasting a mass of lead oxides and sulfuric oxide into grids of lead-antimony alloy. 

Stefanovsky, S. V. 1989. The effect of sulfur oxide (VI) on phase separation in sodium borosilicate glasses. Glass and Ceramic, 3, 10-11 (in Russian). 

Oxidation and extraction, that is, liquid-phase oxidation with organic peroxides followed by separation of the oxidized sulfur (oxidative desulfurization, ODS) [51-58]. 

The sulfur oxidation is carried out at pressure higher than 8 atm and below 180 °C, with a proprietary supported-Mo oxide-based catalyst, for example, an alpha alumina-supported MgMo04 catalyst, operating at 110 °C and 17 atm [59c]. All the products produced by oxidation side reactions and by hydroperoxide reduction are separated from the gas oil stream together with the sulfones. This operation may result in diesel yield loss therefore, the valorization or upgrade of this oxidized stream affects the process economics. This stream can be blended into the heating oil pool or treated in a hydrocracking unit to recover valuable products. 

The ODS of hydrocarbon fuels consists of the conversion of sulfur compounds in the fuels by oxidation to element sulfur, sulfur oxides, sulfoxides, and/or sulfones followed by adsorption or abstraction separation of the oxidized sulfur compounds from the hydrocarbon fuels. The potential advantages for ODS are (a) the process does not need to use H2 gas (b) ODS takes place at relatively mild operating conditions in comparison with HDS or even at ambient conditions and (c) ODS is able to remove some refractory sulfur compounds, such as 4,6-DMDBT, that are difficult to be removed by HDS or selective adsorption. 

Direct application of heat via in situ combustion or via superheated steam generation at the surface and injection are other effective methods to boost production, either in mature oil fields or in heavy oil fields where the petroleum is naturally quite viscous. While both formation heating methods achieve production rate improvements by viscosity reduction, the apparent simplicity of the in situ combustion concept is offset by the difficult separation of recovered oil from an aqueous solution containing nitrogen oxides, sulfur oxides, and other polar combustion products. The acids present in the aqueous phase contribute to the stability of the emulsions obtained from the producing wells and are highly corrosive to steel pipes and tanks. 

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