| 摘要 |
<p>1. A process of producing sulfuric acid from SO2 -containing gases which have been scrubbed, comprising a multistage catalytic reaction of SO2 to SO3 , an interstage absorption of the resulting SO3 after one contact process stage, and an end absorption of the resulting SO3 after the last contact process stage, wherein the SO2 -containing humid gases having a water content which is not in excess of that corresponding to the water balance are dried with concentrated sulfuric acid before entering the first contact process stage, the water that has been absorbed by the dryer acid in transferred with the dryer acid to the absorber acid used to absorb SO3 , absorber acid is recycled at a corresponding rate to the drying stage, the interstage absorption is carried out at elevated temperature and surplus heat from the contact process system is utilized, characterized in that the gases are predried with dilute sulfuric acid having a concentration of 40 to 80% by weight to remove part of the water content from the gases before they are dried with concentrated sulfuric acid, at least part of the water which has been absorbed by the predryer acid is transferred with said acid to the absorber acid used to absorb SO3 , and absorber acid used to absorb SO3 is recycled at a corresponding rate to the predryer.</p> |
