Patent ID: 6685463
Filing Date: 2004-02-03
Classification: F23C,F23M

Abstract:
A method of decreasing NOx emissions in a burner (10) having a main burner body (22) that defines a combustion tunnel (52) and a source of secondary air (26) comprising the steps of:a) flowing supply air (20) into the main burner body (22); b) dividing the supply air (20) into primary air (24) and secondary air (26), wherein the ratio of primary air (24) to secondary air (26) is approximately in the range of 40/60 to 70/30, respectively; c) flowing the primary air (24) into the combustion tunnel (52) at a given velocity; d) flowing primary fuel (38) into the combustion tunnel (52) at a velocity lower than the velocity of the primary air (24); e) flowing secondary fuel (40) into the combustion tunnel (52) at a velocity higher that the velocity of the primary fuel (38); f) flowing the secondary air (26) into the secondary combustion zone (60) at a velocity higher than the velocity of the primary fuel (38); g) igniting the primary fuel (38), the secondary fuel (40), and primary air (24) in the combustion tunnel (52) to form products of combustion (59); h) exhausting the products of combustion (59) into a secondary combustion zone (60); and i) drawing the products of combustion (59) from the secondary combustion zone (60) to a combustion tunnel exit (62) and to the source of secondary air (26).