Method of operating hot air burner

摘要

Heat is removed from the combustion products of the primary combustion zone on its way to a super-stoichiometrically operating secondary combustion zone. Secondary air, which is very much diluted with exhaust gas, is supplied to the secondary combustion zone. The primary air at least is pre-heated by recovery of exhaust gas heat. A burner chamber (8) forms an under-stoichiometrically operating primary combustion zone to which a fuel pipe (9) and a pipe (7) for pre-heated primary air, are connected. The outlet to the burner chamber has an extension (10) the downstream end (14) of which defines the over-stoichiometrically operating secondary combustion zone. The extension is enclosed by an exhaust gas pipe (11) which has an opening (13) for the inflow of the exhaust gas upstream from the secondary combustion zone.