In this process, sulfur dioxide from flue gas is absorbed in a sodium sulfite solution in water forming sodium bisulfite; other components of flue gas are not absorbed.
[1][2] In its initial version (Crane Station, Maryland, 1968) the process was based on potassium sulfite, but the economic prognosis was poor.
Interest in the process occurred because of the worldwide shortage of sulfur in 1967 and resulting high prices; power-plant flue gas was viewed as an additional source of sulfur to relieve the shortage.
the later version used sodium sulfite and was installed (as a demonstration system funded by USEPA) at Mitchell Station, Indiana in 1974.
The process has been offered commercially by Davy Powergas in Lakeland, Florida.