PROCESS FOR PREPARING CHLORINE

A process for preparing chlorine by oxidation of hydrogen chloride in the presence of a heterogeneous particulate catalyst by the Deacon process in a fluidized-bed reactor (1), in which the heat of reaction is removed by evaporative cooling by means of water which circulates in the tubes (2) of a shell-and-tube heat exchanger, with the water being fed from a steam drum (4) via a feed line (5) to the tubes (2) of the shell-and-tube heat exchanger at one end of these, being heated in the tubes (2) by uptake of the heat of reaction and partly vaporizing to give a water/steam mixture which at the other end of the tubes (2) of the shell-and-tube heat exchanger is recirculated via a return line (6) to the steam drum (4), wherein the maximum pressure for which the fluidized-bed reactor (1) has to be designed to allow for the event of rupture of a tube (2) of the shell-and-tube heat exchanger is minimized by a valve (7) which in the event of a pressure increase as a result of rupture of a tube (2) closes the feed line (5) and the return line (6) is installed in the feed line (5) and the return line (6) and thereby prevents water flowing from the steam drum (4) into the fluidized-bed reactor (1), is proposed.