Process for processing mixed acid and waste water from the nitration of aromatics and device for carrying out the process

摘要

In a process for working up mixed acid and waste water from the nitration of aromatics, in which the nitric acid contained is reacted by reaction with an aromatic under adiabatic conditions, a. at least one waste stream component selected from waste acid (mixed acid) accumulating during the nitration, acidic wash water from the processing of crude nitroaromatics and thin nitric acid, which is obtained during exhaust gas treatment during the nitriding, b. the at least one waste stream component mixed with re-concentrated sulfuric acid, c. an aromatic in a stoichiometric excess based on the nitric acid is metered into the mixture, d. the reaction mixture obtained is reacted in an adiabatically operated reactor, e. the organic phase obtained is separated from the sulfuric acid phase in a separator, f. the sulfuric acid phase is concentrated in vacuo, andg. at least a partial stream of the re-concentrated sulfuric acid from step g) is used in step b).