Fluidised bed combustion unit for boiler - uses combustion air to convey fluidised fuel through vertical tubes to combustion chamber above

摘要

The fluidised bed combustion system for powdered solid fuel has a combustion chamber (6) above a grid (4) with a set of horizontal tubes (5) through it. Air supplied through a horizontal chamber (11) at the bottom, under a perforated base (2) conveys the fluidised fuel (3) through the tubes to the combustion chamber above. The air is used for fluidising as well as combustion. Preceding the exhaust gas chimney (9) is an exhaust flap (8) above a dust separator outlet (7) down which the particles are returned to the fluidised fuel bed. The system gives good control of the fuel and air ratio, and reduction of dust emission and good reduction of impurities such as sulphur in the slag.