This article contains content that is written like an advertisement. (January 2022)
The wet sulfuric acid process (WSA process) is a gas desulfurization process. After Danish company Haldor Topsoe introduced this technology in 1987, it has been recognized as a process for recovering sulfur from various process gases in the form of commercial quality sulfuric acid (H2SO4) with the simultaneous production of high-pressure steam. The WSA process can be applied in all industries where the removal of sulfur is an issue.
The wet catalysis process is used for processing sulfur-containing streams, such as:
The energy released by the above-mentioned reactions is used for steam production. Approximately 2-3 tons of high-pressure steam are produced per ton of acid.
Industries where WSA process plants are installed:
The acid gas coming from a Rectisol-, Selexol-, amine gas treating or similar unit installed after the gasifier contains H2S, COS and hydrocarbons in addition to CO2. These gases were previously vented to the atmosphere, but now the acid gas requires purification in order not to affect the environment with SO2 emission. The WSA process provides a high sulfur recovery and recovers heat for steam production. The heat recovery rate is high and the cooling water consumption low, which saves resources.
The WSA process can also be used for the production of sulfuric acid from sulfur burning or regeneration of the spent acid from e.g. alkylation plants. Wet catalysis processes differ from other contact sulfuric acid processes in that the feed gas contains excess moisture when it comes into contact with the catalyst. The sulfur trioxide formed by catalytic oxidation of the sulfur dioxide reacts instantly with the moisture to produce sulfuric acid in the vapor phase to an extent determined by the temperature. Liquid acid is subsequently formed by condensation of the sulfuric acid vapor and not by the absorption of the sulfur trioxide in concentrated sulfuric acid, as is the case in contact processes based on dry gases.
The combustion gases are cooled to the converter inlet temperature of about 420-440°C. To process these wet gases in a conventional cold-gas contact process (DCDA) plant would necessitate cooling and drying of the gas to remove all moisture. Therefore, the WSA process is in many cases is a more cost-efficient way of producing sulfuric acid.
About 80% to 85% of the world's sulfur production is used to manufacture sulfuric acid. 50% of the world's sulfuric acid production is used in fertilizer production, mainly to convert phosphates to water-soluble forms. according to the Fertilizer Manual published jointly by the United Nations Industrial Development Organization (UNIDO) and the International Fertilizer Development Center.