Fluidised bed combustion apparatus.

摘要

A fluidised bed furnace and boiler for the combustion of flyash with a moisture content of 45% by weight. The flyash is produced as a by-product of a coal gasification process and transported in water to a slime dam. From the slime dam a slurry of flyash and water is initially thickened in a gravity thickener (1) and then converted to filter cake in a tubular filter press (4). The filter cake is fed through pressurised hoppers (8) and chutes to the base of the boiler (10) and is distributed across the floor through chutes in the side walls and through chutes surrounded by a tubular array of water tubes and extending into the boiler furnace chamber terminating approximately one quarter of the furnace width from the side walls. A fluidised bed with a depth of about 3 metres is formed by discharging air heated in an associated air heater through nozzles in the floor of the furnace chamber to effect combustion. The combustion gases are utilised to produce steam in the boiler and are passed through a grits separator (32) and bag filter (34) before discharge through a flue (36).