GB927660A - - Google Patents

Abstract

927,660. Furnaces for treating fluidizable materials. BADISCHE ANILIN- & SODAFABRIK A.G. Sept. 1, 1961 [Sept. 3, 1960], No. 31511/61. Classes 51 (1) and 51 (2). To decrease the discharge of dust from a fluidized bed furnace, an insertion is provided which overlies the bed substantially completely, and which defines with the walls of the furnace an opening for the gases which has a cross-sectional area greater than that of the bed. As shown in Fig. 1, the insert 112 is of ceramic material, and sits on an annular ring of water pipes 110 having inlet and outlet pipes 111. The furnace walls are lined with cooling pipes 106 running between top and bottom headers 106a and 106b, over a refractory lining 107. The gas is supplied through a pipe 103 and a windbox 104 and after passing through the bed 101 is slowed by the larger area of the stilling chamber, and then speeds up as the chamber constricts towards the vent 113. As shown in Fig. 2, the temperature of the bed is regulated by a pipe 206. The cooling pipes 202 run horizontally round the furnace, and form a constriction above the insert 208, which consists of an annular ring of pipes with a hole 209 in the centre through which material can return to the bed. Above the constriction is a nest of pipes 211 forming part of a conventional steam boiler. As shown in Fig. 3, the fluidized bed 301 is of square crosssection, but the furnace chamber above is of circular cross-section. The insert is formed of a spiral of pipes above a rammed refractory mix which reflects heat back down to the bed. Pipes 307, 308 are provided with tangential nozzles which blow air into the furnace, causing a vortex in the stilling chamber, which helps to deposit the particles from the gases on to the peripheral walls.