Process for operating a gas phase phosgenation plant

US9845286B2 · kind B2 · utility

Assignee

• Covestro Deutschland AG · DE

Inventors

• Thomas Knauf · Dormagen, DE
• Wolfgang Lorenz · Dormagen, DE
• Friedhelm Steffens · Leverkusen, DE
• Rainer Bruns · Leverkusen, DE
• Wolfgang Taube · Neuss, DE

Key dates

• Filing date: Mar 24, 2015
• Grant date: Dec 19, 2017
• Expiry date: Mar 24, 2035

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01J2219/24
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

This invention relates to a process for operating a gas phase phosgenation plant (100) to form an isocyanate (4) by reacting an amine (2) with phosgene (1), in which the gas phase phosgenation plant is shut down by first stopping the amine stream and still maintaining the phosgene stream. After a period of time which corresponds to at least 10 times the residence time of phosgene (1) in the main parts of the gas phase phosgenation plant (100) in regular operation, calculated from the time at which the amine inflow has been completely stopped, the feed of phosgene is also stopped. An inert gas stream (3) is maintained through the amine and phosgene feeding devices and through all the other essential parts of the gas phase phosgenation plant (100) during the shutdown.