Vesiaatomointi

Vesiaatomointi, also known as hydrodesulfurization (HDS), is a catalytic chemical process used in petroleum refineries to remove sulfur compounds from crude oil and its fractions. This process is essential for producing cleaner fuels that meet environmental regulations and prevent sulfur dioxide emissions during combustion.

In HDS, hydrocarbon feedstocks are reacted with hydrogen gas at elevated temperatures and pressures in the presence of a catalyst, typically molybdenum or tungsten sulfides supported on alumina. The sulfur atoms within the hydrocarbon molecules react with hydrogen to form hydrogen sulfide (H₂S), a gaseous compound that can be easily separated from the liquid hydrocarbons. Organic sulfur compounds like thiophenes, mercaptans, and sulfides are converted into H₂S and the corresponding hydrocarbon.

The primary goal of vesiaatomointi is to reduce the sulfur content of fuels such as gasoline, diesel, and jet fuel. Sulfur removal not only mitigates air pollution but also protects downstream refining equipment, such as catalytic reformers, from sulfur poisoning. The hydrogen sulfide produced during the process is often sent to a Claus unit for conversion into elemental sulfur, a valuable byproduct. The efficiency of HDS is dependent on factors like temperature, pressure, hydrogen partial pressure, catalyst activity, and the type and concentration of sulfur compounds in the feedstock. Modern refineries employ sophisticated HDS units to achieve very low sulfur levels in finished products.