Method for starting up and shutting down a phosgene generator

US9815703B2 · kind B2 · utility

Assignee

• Covestro Deutschland AG · DE

Inventors

• Thomas Knauf · Dormagen, DE
• Andreas Rausch · Regensburg, DE
• Dirk Manzel · Moers, DE
• Charles Bjoerndahl · Hohenwestedt, DE
• Matthias Ehlers · Marne, DE
• Carlos Alvarez Herrero · Tarragona, ES
• Francisco Munoz Velasco · Tarragona, ES

Key dates

• Filing date: Jan 16, 2015
• Grant date: Nov 14, 2017
• Expiry date: Jan 16, 2035

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01J2219/00051
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

The present invention relates to a method for operating a phosgene generator for producing phosgene by reacting carbon monoxide with chlorine in the gas phase on an activated carbon catalyst arranged in a reaction chamber, in which method, after a predefinable operating period, the phosgene production is at least temporarily interrupted by shutting down the phosgene generator over a shutdown period and, after a predefinable downtime, is resumed by starting up the phosgene generator over a start-up period, wherein the method is characterized in that the activated carbon catalyst, before the phosgene generator is started up, is freed of chlorine by adding carbon monoxide so that, during the start-up period, a maximum concentration of chlorine in the gas stream immediately downstream of the reaction chamber of 1000 ppmv is not exceeded. The invention also relates to the use of the phosgene thus obtained in the production of polycarbonate and isocyanates.