A desanding vessel is inserted in a high velocity fluid stream containing entrained particulates. The vessel comprises an upper freeboard portion having a large cross-sectional wherein the fluid stream velocity drops and particulates fall from suspension. Preferably the fluid stream is introduced offset upwardly from an axis of a horizontally oriented cylindrical vessel, released particulates falling to accumulate in a lower belly portion. The freeboard portion is maintained using a depending flow barrier adjacent the vessel's outlet which sets the depth of accumulation in the belly portion. A cleanout enables periodic removal of accumulations.