| 摘要 |
<p>Improvements are disclosed for a process for producing oleum from a spent acid mixture of ammonium bisulfate and dilute sulphuric acid in which the mixture is pyrolyzed by feeding spent acid, fuel and air into a furnace to obtain gaseous oxide products including SO2, oxidizing the SO2 to SO3 with oxygen and absorbing the SO3 in concentrated sulfuric acid to form oleum. The improvements comprise (a) feeding the furnace with air that contains 22-40% oxygen by volume, (b) collecting the gas remaining after absorption of SO3 in concentrated sulfuric acid, increasing oxygen content to 22-40% by volume and feeding portions of the resulting mixture to the furnace, or (c) separately heating the spent acid to 100-200.degree.C and the air to 600-1000.degree.C prior to feeding the heated acid and air directly into the furnace.</p> |
