Low N2O, NO and SO2 emissions from circulating fluidized bed boilers
Konferensbidrag (offentliggjort, men ej förlagsutgivet), 1995

A new method, reversed staging, for decreasing N2O without increasing the emission of the other pollutants, NOx and SO2, was investigated in the 12 MW circulating fluidized bed boiler at Chalmers University of Technology. It was possible to reduce the emission of N2O to one fourth (25 ppm), NO to half (about 40 ppm) compared to normal staging and normal temperature, without significantly affecting the sulphur capture efficiency (about 90%). Air staging, which is normally used in circulating fluidized bed boilers means that only a part of the combustion air, primary air, is added to the bottom zone, resulting in a lower oxygen concentration in the bottom part, while the secondary air results in more oxidizing conditions in the upper part of the combustion chamber and the cyclone. The principal idea of reversed staging is to reverse the conditions in top and bottom, i.e. to decrease the oxygen concentration in the upper part and to increase it in the bottom part. Such a reversal is accomplished by adding air in the bottom corresponding to an air ratio of approximately unity. No secondary air is added to the combustion chamber which means that the oxygen concentration will be low in the upper part of the combustion chamber and the cyclone. Air for final combustion is added in the cyclone outlet.

NO and N2O

nitric oxides

Fluidised bed combustion

nitrious oxide

Författare

Anders Lyngfelt

Chalmers, Institutionen för energiteknik

Lars-Erik Åmand

Chalmers, Institutionen för energiteknik

Bo G Leckner

Chalmers, Institutionen för energiteknik

Proc. Int. Conf. Fluid. Bed Combustion

0197-453X (ISSN)

Vol. 13 1049-1057

Drivkrafter

Hållbar utveckling

Ämneskategorier

Energiteknik

Kemiteknik

Annan naturresursteknik

Styrkeområden

Energi

Infrastruktur

Chalmers kraftcentral

ISBN

07918-1305-3