PROCESS FOR THE SEPARATION OF SULPHUR OXIDES FROM OFFGASES

摘要

A process is provided herein for the separation of sulphur oxides from offgases. The process includes the first step of passing the sulphur oxides-containing offgas through a fixed bed of a sulphur oxide adsorbent. The sulphur oxide adsorbent has catalytic activity for the oxidation of sulphur oxides to sulphur trioxide, and comprises a mixture of vanadium pentoxide and pyrosulphates of one or more alkali metals which is supported on a porous carrier, at a temperature from 250 .degree. C to 400C .degree. . The sulphur oxides which are adsorbed on the adsorbent are then converted to sulphur trioxide to provide a sulphur trioxide-loaded adsorbent. The sulphur trioxide-loaded adsorbent is regenerated with recirculating air at a temperature from 500.degree. to 650.degree.C. A part of the regeneration air is recirculated to the fixed bed of the adsorbent. Finally, desorbed sulphur trioxide in the regeneration air is removed by hydration of the desorbed sulphur trioxide to sulphuric acid, and the sulphuric acid so-formed is condensed in a sulphuric acid condenser.