Submerged combustion burners having a burner body and a burner tip connected thereto. The burner body has an external conduit and first and second internal conduits substantially concentric therewith, forming first and second annuli for passing a cooling fluid therethrough. A burner tip body is connected to the burner body at ends of the external and second internal conduits. The burner tip includes a generally central flow passage for a combustible mixture, the flow passage defined by an inner wall of the burner tip. The burner tip further has an outer wall and a crown connecting the inner and outer walls. The inner and outer walls, and the crown are comprised of same or different materials having greater corrosion and/or fatigue resistance than at least the external burner conduit.

A combustion apparatus comprising: a combustion chamber; a primary fuel input conduit for supplying a fuel to the combustion chamber; a secondary input conduit for supplying a combustion gas to the combustion chamber; and combustion gas supply means, wherein the combustion gas supply means is adapted to switchably supply one of air and an oxygen rich gas to at least the secondary input conduit.