Keywords: Ammonium sulphate fertiliser.

General Electric Environmental Services, Inc. (GEESI) has developed, patented and commercialised an innovative process for the production of ammonium sulphate. The unique process produces the highest quality ammonium sulphate by removal of unwanted sulphur dioxide from utility or industrial boiler flue gas by reacting it with ammonia and air to form ammonium sulphate.

This energy efficient process uses the waste energy from the boiler flue gas to crystallise the product by evaporation of excess water. The first commercial Ammonium Sulphate Forced Oxidation (ASFO) system, is being installed at the Dakota Gasification Company’s (DGC) Great Plains Synfuels Plant near Beulah, North Dakota, USA. This plant is designed to produce more than 500 tonnes per day of granular ammonium sulphate.

This process produces the highest quality ammonium sulphate product while simultaneously reducing emissions of unwanted sulphur oxides. This paper describes the results of the process demonstration unit, the process chemistry and the first commercial plant. The quality and properties of the by-product formed and the economics of ammonium sulphate production are also discussed.

G N Brown, General Electric Environmental Services Inc., Lebanon, PA, USA.

19 pages, 6 figures, 3 tables.