An air-oxygen hydrogen sulphide burner (108) fires into a furnace (102). The burner comprises a main passage for combustion-supporting gas containing air (112), a multiplicity of spaced apart outer elongate fluid-conducting open ended tubes extending in parallel with each other along the main passage, each of the outlet tubes surrounding at least at the distal end of the burner a respective inner elongate fluid-conducting open ended tube, the inner tubes extending in parallel with one another, a first inlet to the burner for oxygen or oxygen-enriched air, and a second inlet to the burner for feed gas containing hydrogen sulphide, the first inlet communicating with the inner tubes, and the second inlets communicating with the outer tubes. |