Wet sulfuric acid process

The wet sulfuric acid process (WSA process) is applied in lots of industries where removal of sulfur is an issue, such as refinery and petrochemical industry, sulfuric acid industry, and metallurgy industry. WSA was introduced by Danish catalyst company Haldor Topsoe in the late 1980s.

WSA process is to convert various sulfides in acid gas into concentrated sulfuric acid, and the condensing device is a condenser. The process is as follows: acid gas is burned to produce SO2, converted into SO2 wet gas is cooled into SO2 converter to produce SO3, SO3 and the water vapor carried into the condenser to directly condense into acid. The WSA process is actually a catalytic reaction process, which is particularly suitable for the treatment of acidic gases with low sulfur concentrations that cannot be treated by conventional sulfuric acid processes.

WSA process is ideal for handling various concentrations of sulfur-containing gases, which can range from a few tenths of a percent to very high concentrations, as well as process gases with a fairly high moisture content without drying prior to treatment. Even if the water in the acid gas is excessive by 30% to 50%, the mass concentration of the finished acid can reach 93% to 94%. In addition, the process is simple and energy efficient, and can still be self-heated when the acid gas SO2 volume fraction is as low as 3%. At present, more than 50 WSA units have been built or are under construction around the world, and these WSA units are used in many industrial industries, processing acidic gas flows up to millions of cubic meters per hour, and sulfuric acid production up to 1100t per day.