Abstract: Commercial production of sulfuric acid is almost entirely accomplished nowadays using the contact process. And the trend is to increase conversion efficiency and reduce emissions of unconverted sulfur dioxide. By using a special combination of contact catalyst beds, a single contact single absorption (SCSA) system can be engineered to achieve the conversion and emission capabilities of conventional double contact double absorption systems. Thus, the complexity and cost of incorporating a second absorption tower and associated heat exchanger in the system can be omitted. In the SCSA system, the initial catalyst bed or beds comprise vanadium oxide catalyst and the last catalyst bed or beds comprise platinum catalyst operating at a much lower temperature than the initial beds.

Abstract: A contact process, sulfuric acid system and method are disclosed for producing sulphuric acid with improved operating efficiency in humid environments. The system comprises a pre-drying absorber for pre-drying humid air with weak sulfuric acid. Weak sulfuric acid from the pre-drying absorber is provided to a subsystem comprising two sulfur trioxide absorbers and a heat exchanger for the recovery of heat via steam production. This arrangement allows for a marked increase in steam production (i.e. energy efficiency). In a separate improvement, the emission apparatus for the system can be simplified using a peroxide tail gas scrubber comprising upper and lower scrubber sections in which the upper scrubber section consists essentially of tray type scrubbers.

Abstract: The invention relates to a continuous process for purifying a gas containing 60-99 percent SO2 (sulfur dioxide) by volume and 1 to 40 percent steam by volume, followed by synthesis of SO3 (sulfur trioxide) without first drying the gas, and to an apparatus for carrying out said method.

Abstract: A side stream subsystem can be used to remove impurity species from the recirculating alkali metal chloride solution in certain electrolysis systems. Silicon and/or aluminum species can be removed via precipitation after introducing an alkali metal hydroxide and magnesium chloride in a side stream line in the subsystem. The invention can allow for a substantial reduction in raw material and capital costs.

Abstract: A liquid distribution trough contained within a tower for the purpose of mass or thermal exchange between at least a first liquid and a second fluid; the trough having an upper section and a lower section; the lower section for receiving the first liquid; a horizontal dividing member separating the upper section from the lower section and having at least one dividing member portion defining an aperture to allow for passage of the liquid fluid from the lower section to the upper section; a feed conduit means in communication with the lower section to provide feed first liquid flow to the lower section; the lower section having at least one inlet portion defining a liquid inlet in communication with the feed conduit means; and a first baffle adjacent the inlet portion operably impacted by the first liquid flow and to hinder preferential flow along the walls of the trough and the dividing member. The trough and tower are of particular value in a sulphuric acid plant and a carbon dioxide capture plant.

Abstract: A process for reducing the concentration of perchlorate in an aqueous concentrated multi-component salt solution comprising treating the salt solution with an amphoteric ion-exchange resin to provide an adsorbed perchlorate and multi anion-containing resin and a perchlorate depleted solution; and removing the perchlorate depleted solution. The multi-anion are selected from chloride, chlorate, perchlorate, sulphate, and dichromate, present in electrolytic processes for the production of sodium chlorate.