GB667901A - Improved process for the intensive manufacture of sulphuric acid - Google Patents

Abstract

In making sulphuric acid by reacting sulphurous gases, oxygen and water in the presence of nitrosyl-sulphuric acid dissolved in concentrated sulphuric acid having a concentration of over 60 DEG B<\>ae, the reaction for the formation of sulphuric acid is effected concurrently with the recovery of the nitrous gases liberated by the reaction of SO2 with the nitrosyl sulphuric acid, and for each molecule of absorbed SO2 not less than 5 molecules of nitrosylsulphuric acid are employed, the acid to be transformed into the final product being diluted before its denitration or in the same denitration apparatus. The reaction may be effected in an absorption system composed a number of compartments e.g. an arrangement of absorption towers, in which sulphurous gases are sprinkled with nitrosulphuric acid of constant composition drawn from a single container which is fed by the acids from the different compartments. Alternatively, the reaction may be effected by causing the nitro-sulphuric acid to circulate continually in a single circuit either from the last compartment to the first or vice versa, Fig. 2 (not shown). The composition of the circulation acids may be maintained constant by introducing water, as liquid or steam, or dilute nitric acid, at any suitable point of the absorption cycle. Denitration may be effected by heating or by the action of cool sulphurous gases prior to their introduction into the system, the liberated nitrous products being returned to the absorption system. Hot sulphurous gases are cooled before use in denitration and the heat therefrom is utilized for supplementary concentration of the denitrated acid to give a final product, e.g. 60 degrees Be H2SO4.