METHOD FOR STARTING UP AND SHUTTING DOWN A PHOSGENE GENERATOR

摘要

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.

主权项

1. A method of operating a phosgene generator for preparing phosgene by reacting carbon monoxide with chlorine in the gas phase over an activated carbon catalyst which is arranged in a reaction space, comprising interrupting the preparation of phosgene at least at times after a prescribeable period of operation by running down the phosgene generator over a running-down time and, after a prescribeable stoppage time, recommencing the preparation of phosgene by starting up the phosgene generator over a start-up time,
wherein the activated carbon catalyst is freed of chlorine before starting up the phosgene generator by introducing carbon monoxide to such an extent that a maximum concentration of chlorine in the gas stream immediately downstream of the reaction space of 1000 ppmv is not exceeded during the start-up time.