Patent ID: 8141502
Filing Date: 2012-03-27
Classification: F23C

Abstract:
1. A fluidized bed boiler comprising a circulation of heat transfer medium and a furnace, said furnace comprising: an inner volume, a lower part comprising a grate comprising a plurality of elongated elements spaced at intervals next to each other, wherein the elongated elements are arranged in a profile having substantially the same shape over a length of the elongated elements in a longitudinal direction of the elongated elements, said elongated elements comprising means for supplying fluidizing air into the furnace and leaving openings in areas between the elements, said openings extending parallel to the elongated elements and being configured to discharge coarse material from the bed through the openings into a discharge unit underneath the grate, and at least one heat transfer surface extending through the inner volume of the furnace; said heat transfer surface comprising elongated heat transfer tubes on top of each other and being supported from underneath, over its whole length, on the grate in a section extending through the inner volume of the furnace, wherein the heat transfer surface is arranged on top of one of the elongated elements of the grate, in parallel with the longitudinal direction of the one elongated element of the grate, and supported from underneath over its whole length on the one elongated element of the grate, said elongated heat transfer tubes being arranged on top of each other and extending parallel to the longitudinal direction of the one elongated element.