| 摘要 |
Method and apparatus for using biofuel or waste material or both for energy production. The biofuel or waste material is gasified in a fluidized bed gasifier (10), preferably a circulating fluidized bed gasifier. The gas produced in the gasifier is introduced into a boiler (12) equipped with fossil fuel burners (28, 28', 28''), typically burners for pulverized coal. The gas is introduced at a level above the burners. Ash from the boiler may be used to form the bed of the gasifier. For control of NOx, the gas is burnt in the upper part of the boiler at a low temperature level of 800 - 1050 ~C (1472 1922F), preferably 850 - 900 ~C (1562 - 1652F), and with a small excess air content of about 5 - 10 %. In a second embodiment, the raw gas may be cleaned of harmful or noxious components, and cooled if desired, between the gasifier and the boiler in an additional circulating fluidized bed reactor (152) having a bed of coal ash.
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