Wastage of Water Wall Tubes in a Circulating Fluidized Bed Combustor with Two Gas Exits

Abstract

The tube wastage profiles of water walls are discussed in a commercial CFB furnace with two gas exits. The lateral profile of wear rate confirms that tube wastage is influenced mainly by secondary flow, stronger toward the center than in the corners, and somewhat by the wing walls and gas exits. The effect of two superposed secondary flows of the second kind, one caused by the shape of the entire freeboard cross-section and the other by sections between the wing walls, could also be confirmed in lateral profiles of tube erosion rate on the wall connected with wing walls. Appreciable tube erosion rate was confirmed near the center of the rear wall at lower heights and near the center of both sidewalls at heights above the gas exit level. Wastage or wing walls increased with distance into the interior of the furnace.