Method for producing phosgene

摘要

A process for preparing phosgene by reaction of a feed stream (1) obtained by combining and mixing a chlorine feed stream (2) and a carbon monoxide feed stream (3), with the carbon monoxide being introduced in a stoichiometric excess over chlorine, in catalyst tubes filled with beds of activated carbon in a reactor R having a bundle of catalyst tubes,;to give a product gas mixture (4);which is separated into a liquid, phosgene-comprising product stream (5) and an offgas stream (6) comprising carbon monoxide which is discharged via a pressure-regulating valve, where the reaction of the feed stream (1) in the reactor R and the separation of the product gas mixture (4) are carried out under a pressure in the range from 2.0 to 6.0 bar gauge pressure, wherein;the excess of carbon monoxide in the feed stream (1) to the reactor R is regulated by continuously measuring the flow and the concentration of carbon monoxide in the offgas stream (6), calculating the actual value of the excess of carbon monoxide in the feed stream (1) to the reactor R from these measurements in combination with the continuously measured values for the flow of the carbon monoxide feed stream (3) and the flow of and the chlorine concentration in the chlorine feed stream (2) and matching this to the intended value of the excess of carbon monoxide in the feed stream (1) to the reactor R by adapting the flow of the carbon monoxide feed stream (3), is proposed.

主权项

1. A process for preparing phosgene, the process comprising:
reacting a reactant feed stream obtained by combining and mixing a chlorine feed stream and a carbon monoxide feed stream, wherein the carbon monoxide is introduced in a stoichiometric excess over chlorine, in catalyst tubes filled with beds of activated carbon in a reactor comprising a bundle of catalyst tubes, to give a product gas mixture which is separated into a liquid, phosgene-comprising product stream and an offgas stream comprising carbon monoxide which is discharged via a pressure-regulating valve, wherein the reaction of the reactant feed stream in the reactor and the separation of the product gas mixture are carried out under a pressure in the range from 2.0 to 6.0 bar gauge, and wherein the excess of carbon monoxide in the reactant feed stream is regulated without directly measuring the concentration of the carbon monoxide in the carbon monoxide feed stream by
continuously measuring (i) the flow and the concentration of carbon monoxide in the offgas stream, (ii) the flow and concentration of the chlorine in the chlorine feed stream, and (iii) the flow of the carbon monoxide feed stream,calculating the actual value of the excess of carbon monoxide in the reactant feed stream from measurements (i), (ii), and (iii), andmatching the actual value of the excess of carbon monoxide in the reactant feed stream to an intended value of the excess of carbon monoxide in the reactant feed stream by adjusting at least one selected from the group consisting of the flow of the carbon monoxide feed stream and the flow of the chlorine feed stream.