GB590432A - Improvements in the production of chlorine dioxide - Google Patents

Abstract

In the production of chlorine dioxide by passing, under pressure, chlorine gas and an inert diluent gas to a mixing zone and passing the mixture in contact with a chlorite, the chlorine supply line is maintained open to the flow of chlorine by means of pressure of the diluent exerted in opposition to a constantly applied mechanical force tending to close the supply line, the force being such as to stop the supply of chlorine should the pressure of the diluent fall below a predetermined value. In the apparatus shown in Fig. 1 chlorine gas under pressure is passed through filters and control valves to a meter device, such as a capillary flow meter (see Group XX) indicated at 30, and thence through a flow-control valve 37 (see Group XXIX) which is connected through lines 47 and 49 to a high pressure air line 43 and a chlorine-air mixing line 17 leading to the reaction chambers. Air, preferably dry and under high pressure, is supplied by way of line 39, driers 41, control valves 44 and 46 to mix with the chlorine in line 17. The flow of both air and chlorine may be automatically regulated by valves 46 and 46a. Two reaction chambers 1 and 2 are provided with valve controlled inlets 3 and 4, exist lines 5 and 6 and lines 11 and 12 connecting alternate inlet and exit lines. The chlorine dioxide and air mixture issuing from the reaction chambers passes through line 18 to a gas manifold 51, where it is led through a plurality of valve controlled lines 52, flow meters 53 and lines 54 to the various treating operations. When it is desired to further dilute the chlorine dioxide-air mixture prior to use, air is led from line 43 through a by-pass comprising valve controlled lines to a manifold 62, where it is directed <PICT:0590432/III/1> through valve-controlled lines 63 to the gaseous mixture in lines 54. All parts of the apparatus that come in contact with chlorine and chlorine dioxide are desirably constructed of non-corrosive material, such as silver, corrosion resistant alloy e.g. "Hastelloy-C" (Registered Trade Mark), glass, stoneware or plastics e.g. "Saran." The Specification describes the use of a reaction chamber which is the subject-matter of Specification 590,450. Specification 564,162 also is referred to.