Covestro Deutschland Ag

Other

Bayer Materialscience Ag

Covestro Intellectual Property Gmbh & Co. Kg

Peter Drinda

Thomas Knauf

Klaus Pilarczyk

Stefan Wershofen

Klaus-Gerd Gruner

Volker Hartjes

Franz-Ulrich Von Gehlen

Jörg Schmiedler

Thomas Rosin

A process for purifying nitrobenzene-contaminated wastewater stream WWincludes stripping WWwith stripping gas SGin a stripping column to obtain wastewater stream WWcontaining reduced concentration of nitrobenzene relative to WW(c), and purifying WWin a wastewater treatment plant, wherein a target value (c) is specified for the nitrobenzene concentration in WW. A set of linear mathematical relationships is stored in a database for a combination of boundary conditions of nitrobenzene concentration in WW, temperature of WW, and temperature of SG. This set defines a range of concentrations of nitrobenzene in WWand includes a mathematical relationship corresponding to c, a mathematical relationship for a value of ccorresponding to 98% of c, and a linear mathematical relationship for a value of ccorresponding to 102% of c. The concentration of nitrobenzene is controlled in WW(c) by adjusting the flow rate of SG

Method for cleaning aqueous wastewater streams loaded with nitrobenzene

The present invention relates to a process for the continuous production of nitrobenzene by the nitration of benzene with nitric acid and sulphuric acid under adiabatic conditions, not the entire production plant being shut down during a production stop, but the production plant being entirely or at least partly operated in recirculation mode. The invention further relates to a plant for producing nitrobenzene and to a method for operating a plant for producing nitrobenzene.

Process for producing nitrobenzene

This invention relates to methods for producing chemical products, wherein the one or more feed materials are reacted to form a chemical product or a chemical composition. The invention further relates to plants for performing such methods, said plants being designed in such a way that, during an interruption of the methods, no input of at least one feed material into the reaction occurs and the plant parts not affected by a revision measure, maintenance measure, repair measure, or cleaning measure are operated in so-called re-circulation mode. It is thereby achieved, among other things, that only the affected plant part needs to be shut down for the time of the measure, which can be advantageous with regard to the productivity and economy of the method and the quality of the produced products. Finally, the invention relates to methods for operating plants in the event that individual plant parts are taken out of service.

Methods for producing chemical products with operation interruptions

Nitrobenzene is produced and then purified using an acidic wash, an alkaline wash, a neutral wash, subjecting a dispersion formed in the neutral wash to electrophoresis to separate water and benzene from the nitrobenzene and recover purified nitrobenzene.

Process for the production of nitrobenzene

Growing community of inventors

Krefeld, Germany

Peter Drinda