Reduction of emissions of nitrous oxide from fluidized-bed combustion

Övrigt konferensbidrag, 1994

An account is given of the first attempts to reduce the emissions of nitrous oxide (N2O) from atmospherc fluidized bed combustion. Four methods are considered: 1) Rise of bed temperature and change of air supply to the combustion chamber, 2) Use of catalysts in the combustion chamber, 3) Rise of the flue gas temperature downstream of the combustion chamber 4) Low excess air. Methods 1) and 2) tensd to raise other emisions, such as NO and SO2, as the N2O emission is reduced, and method 4) only gives a small contribution to N2O reduction. Afterburning (Method 3) does not affect SO2 and reduces somewhat the NO and CO emissions at the same time sa N2O is removed, but requires an additional fuel and a correspondinf combustion chamber. An example is given of the use of the cyclone of a circulating fluidized bed as an additional combustion chamber.