US Patent 7998421 Particle treatment in an expanded toroidal bed reactor

A method of processing a fluid and/or a particulate material, the method comprising the steps of: (a) introducing the particulate material into a chamber; (b) providing a flow of fluid into said chamber for entraining the particulate material; and (c) removing processed fluid and/or particulate material from the chamber; wherein the chamber comprises a processing zone having a substantially circular transverse cross-section, the fluid flow being introduced into the processing zone at an angle of between 10° and 75° with respect to a tangent of the substantially circular transverse cross-section of the processing zone to establish a fluid flow following a substantially helical path in the processing chamber.