A METHOD AND DEVICE FOR FIRING SOLID FUELS, MAINLY IN THE FORM OF LUMPS OR PIECES

摘要

Method and device for firing solid fuels, substantially in the form of lumps or pieces, in a furnace having a combustion chamber (1) with a sustantially horizontal bottom (10), upon which is maintained a fuel bed (3) with relatively great thickness while supplying fuel within the very bed (3), through which bed primary combustion air is fed from below through mutually spaced primary air passages (18) in the combustion chamber bottom (10), the combustion gas which leaves said chamber (1) furthermore being subjected to a subsequent secondary combustion in a secondary combustion chamber after addition of secondary combustion air. In order to provide for a mechanical removal of ash the invention suggests that the fuel is supplied into the bed positively and intermittently at a position on an end wall of said combustion chamber (1) at a vertical height spaced above the bottom (10) of the latter but below the upper surface of the fuel bed during operation of the furnace and substantially in horizontal direction, whereby at each occasion newly supplied fuel provides an an agitation of the bed (3) such that a concentrated combustion zone is obtained at the upper portion of the bed, while finally combusted fuel in the form of ash is progressively moved towards the opposite end wall of the combustion chamber (1) and downwards and along the combustion chamber bottom (10), wherefrom the ash is removed in horizontal direction during furnace operation.