Thread Content
Fuming sulfuric acid is a sulfuric acid solution of SO3; its molecular formula is H2SO4·XSO3. It is a colorless or slightly colored viscous liquid, and when exposed to air, it releases toxic SO3 fumes, which is why it is called fuming sulfuric acid. Precautions for the production of fuming sulfuric acid: 1. Fuming sulfuric acid has a high freezing point; therefore, its production is only possible in the northwestern region from May to October. After October, the fuming sulfuric acid stored in the tanks must be emptied, and the pipes and tanks should be rinsed with 93% sulfuric acid ； 2. When producing fuming sulfuric acid, it is prohibited to add water to the 104.5% fuming sulfuric acid absorption tower; a protective shield must be lowered when taking samples ； 3. It is strictly prohibited to allow the concentration of fuming sulfuric acid to exceed the specified range for an extended period of time during its production ； 4. After the production of fuming sulfuric acid is complete, when reducing the concentration in the circulation tank of the 104.5% fuming sulfuric acid absorption tower, it is necessary to ensure that the acid concentration in the second absorption tower does not exceed 99.5%; otherwise, excessive smoke will be emitted from the exhaust gases ； 5. High-concentration fuming sulfuric acid is highly volatile; the free SO3 that evaporates into the environment causes severe pollution and poses a great threat to human health as well as to related equipment. Source: \"Modern Guidelines for Sulfuric Acid Production Operations and Technology\"