Oil fired water tube boiler - is modified for coal firing by adding down-flow precombustion chamber connected to main combustion chamber

摘要

The arrangement is particularly intended for modifying an existing oil-fired water tube boiler installation for firing with pulverised coal. The original boiler comprises a combustion chamber (1) with tube walls. The modification includes the addition of one or more precombustion chambers (4) with tube walls. The combustion gases pass from the top downwards to an outlet opening (6) connected (7) to the combustion chamber. Pulverised lime may be injected (9) in the combustion chamber to neutralise sulphur dioxide. A transport worm (8) may be installed in the combustion chamber to remove unburnt coal rests. One or more further heating surfaces (11) may be installed between the boiler and the air preheater (10).