Abstract: Disclosed is a method for recovering diluted waste sulfuric acid containing impurities from nitration processes, a highly concentrated nitric acid required in the nitration process being produced in association with the nitration process by means of extractive rectification with concentrated sulfuric acid which is re-concentrated in order to be reutilized. According to the inventive method, the waste sulfuric acid from the nitration process is fed to the top of a first, indirectly heated stripping column, optionally together with another waste sulfuric acid in the form of a DNT washing acid, and is divided into an overhead product containing nitric acid and nitro-organic compounds as well as a prepurified sulfuric acid in the bottom product.

Abstract: A column tray assembly includes a tray having passages formed therein. The tray is a multifunction tray and is configured to receiving appropriate superstructures which can be selected according to the respective use of the assembly. Superstructures which communicate with the passages are mounted to the tray. The superstructures have gas penetration holes embedded in such way that, when the superstructures are mounted to the tray, the orifices of the gas penetration holes extend in a perpendicular manner in relation to the tray. The tray and the superstructures are formed from the same or different corrosion-resistant materials or combination of materials. The tray may also be provided with smaller holes for the discharge of liquid, into which holes distributor cups, or the like are inserted. These smaller holes may be closed for specific purposes.

Abstract: Process for producing a nitric acid of a concentration from 75 to 99.9% from a more diluted nitric acid, wherein a nitric acid of a concentration of about 45 to 70% is rectified in contact with a liquid extraction medium to prevent the formation of a nitric acid-water-azeotropic mixture, and the vapors of the concentrated nitric acid are condensed and a concentrated nitric acid is obtained and wherein additionally the extraction medium is reconstituted through reconcentration and returned into the extractive rectification, wherein the nitric acid to be concentrated is fed as a boiling liquid or partially vaporized to the extractive rectification preferably carried out in two columns (K 1.0, K 1.

Abstract: Glass modules for use in the assembly of equipment, installations and for pipe works, the surfaces of which are entirely or partially coated with a conductive coating, in particular from transparent conductive polymers for the purpose of reducing surface resistance, their use, as well as the equipment, installation and pipe works made therefrom.

Abstract: A column tray assembly includes a tray having passages formed therein. The tray is a multifunction tray and is configured to receiving appropriate superstructures which can be selected according to the respective use of the assembly. Superstructures which communicate with the passages are mounted to the tray. The superstructures have gas penetration holes embedded in such way that, when the superstructures are mounted to the tray, the orifices of the gas penetration holes extend in a perpendicular manner in relation to the tray. The tray and the superstructures are formed from the same or different corrosion-resistant materials or combination of materials. The tray may also be provided with smaller holes for the discharge of liquid, into which holes distributor cups, or the like are inserted. These smaller holes may be closed for specific purposes.

Abstract: A packing for a mass transfer column for absorption, desorption, rectification or extraction processes, includes a packing bed having a packing element, a tubular shrink film shrunk onto at least a portion of a periphery of the packing element, and a baffle arranged at the periphery of the packing element to prevent a wall effect in the column. The baffle has a conical edge which extends outwardly with respect to the shrink film and is made of plastic.

Abstract: A packing for a mass transfer column for absorption, desorption, rectification or extraction processes, includes a packing bed having a packing element, a tubular shrink film shrunk onto at least a portion of a periphery of the packing element, and a baffle arranged at the periphery of the packing element to prevent a wall effect in the column. The baffle has a conical edge which extends outwardly with respect to the shrink film and is made of plastic.