| 摘要 |
<p>A method and an apparatus are described for combusting carbonaceous materials in a two-stage process. In a first reaction chamber (2), operating under fuel-rich conditions in a bubbling fluidisation regime, fuel undergoes primary combustion or gasification. Oxidising gas (5) is fed into the first reaction chamber at a velocity sufficient to maintain fluidisation. Combustion products leave the first chamber and enter a second reaction chamber (3), operating under oxygen-rich conditions as a circulating fluidised-bed combustor. A second stream of oxidising gas (6) is fed to the second chamber, preferably tangentially to generate a turbulent swirl. Particles of a sulphur-capture agent, preferably limestone, are fed to the second chamber, preferably with the second stream of gas. In the second stage, char and combustible gases generated in the first stage are burnt. The fuel-bound sulphur is removed and advantageously converted to calcium sulphate, while the fuel-bound nitrogen is advantageously converted to nitrogen gas.</p> |
