The LO-CAT® II process is used to control H2S emissions and reduce
odors at geothermal power plants.
Geothermal steam, considered to be a clean and environmentally
friendly source of energy, is produced when water seeps into high
temperature, high pressure formations below the earth's surface. The
steam is brought to the surface through production wells and then
expanded through a turbine to produce electricity. Coming out of
the turbine is the condensed steam and any non-condensible gases
(NCG) associated with the steam. The condensed steam is usually
pumped back into the underground formation.
The NCG is mostly carbon dioxide (CO2) but, may contain up to 6%
hydrogen sulfide (H2S). If the H2S concentration is very low, the NCG
is usually vented to the atmosphere through the cooling tower.
However, both the low odor threshold of H2S and the current
environmental laws strictly limit the amount of H2S that may be
vented into the atmosphere.