GB363327A - Improvements in and relating to the production of sulphuric acid - Google Patents

Abstract

<PICT:0363327/III/1> In the manufacture of sulphuric acid, the hydration of the sulphur trioxide produced, is effected substantially completely in the liquid phase by using sulphuric acid, e.g. of 50 per cent concentration in the reaction vessels. Considerable oxidation also takes place in the liquid phase, the gases being forced or drawn through the reaction liquid in a finely divided state. Nitric acid or nitrosylsulphuric acid is supplied as the oxidizing agent and the nitrous gases liberated may be absorbed in water, sulphuric acid or nitric acid. In the Figure shown the sulphur dioxide gases enter a reaction vessel A through a pipe a, and leave through a pipe d, after passing through a number of shelves c provided with holes, slits or cups. The nitrous gases are absorbed in a similar vessel B which is supplied with nitric acid or other absorption medium, the nitrosylsulphuric acid being returned to the vessel A by the pipe k. In order to reduce the temperature of the reaction, cold gases or air may be passed into the vessel A, but preferably the exit gases in the pipe d are reintroduced, after passing a cooler C. Liquid which is condensed from the gases is drawn off by the pipe P. When gases containing a high concentration of sulphur dioxide are used, additional air may be introduced through a pipe s, to re-oxidize the nitrous gases. Gases from the top of the vessel A may be withdrawn at g and re-introduced through the pipe r.