A fluid atomizer and spraying means which is made up of: a mixing chamber into which the fluid to be atomized and the atomizing gas are introduced and in which the fluid is admixed with and dispersed in the gas; a generally conical nozzle means extending from the mixing chamber through which the mixed fluid and gas are forced; and a chamber into which the atomized mixed fluid and gas is sprayed. The conical nozzle means is suitably a relatively narrow frustro-conical passageway which contains support-spacer means which is generally parallel to the direction of flow through the passageway. At least one such support-spacer means is provided which extends from the end of the passageway proximate to the mixing chamber to the end of the passageway proximate to the chamber into which the mixture is sprayed. The preferred use of this apparatus is in atomizing fuel oil with steam and spraying such atomized mixture into a combustion chamber where it is contacted with combustion air. The amount of effluent NOX is reduced and limited by the use of this configuration by creating alternating fuel-rich and air-rich spatial distribution, and allowing the amount of stoichiometric excess air to be severely limited, while causing the substantially complete combustion of the fuel oil.
