(57) The present invention discloses a method of, and apparatus for, reducing NOx emissions
from black coal fired updraught furnaces (20). The pulverised coal is entrapped in
the "primary air" and separated into two streams, one fuel rich (13) and one fuel
lean (15). These streams are introduced into the furnace (20) via a corresponding
burner(s) (14,16) with the burner(s) (16) for the fuel lean stream (15) being located
at an elevation above the burner(s) (14) for the fuel rich stream (13).
The apparatus comprises a concentrator (3) positioned between the substantially conventional
mill (1) and furnace (20) and arranged to split the primary air and entrapped fuel
into the two abovementioned streams. The concentrator preferably includes a classifier
(8) and takes the form of a swirl generator (5) and radially positioned outlets which
make use of the action of centrifugal force on the "primary air" and entrapped coal
particles to bring about the desired separation.
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