Urea Granulation by the Fluid Bed Process (NSM Technology)

There has been a worldwide shift from prilling of urea to granulation because of the more desirable products made in granulators. This shift has taken place to supply growing fertilizer demand for larger, harder, and more dense particles, in spite of the traditionally higher costs associated with granulation. The movement to granulation has been especially strong in North America, where the present split is about half granulation and half prilling.

Until recently all urea granulation was done in rotating drums or pans. Several companies are developing fluidized bed processes for granulating urea that show economies over processes using rotating equipment. The fluid bed process developed by Nederlandse Stikstof Maatschappij (NSM) is the leader, with several commercial installations since the first one in 1979.

In this economic evaluation the NSM fluid bed process compares very favorably with the conventional prilling technique while producing a superior urea product.