Partial oxidation of hydrogen sulphide

Apparatus for the partial oxidation of hydrogen sulphide comprising a furnace and an air-oxygen hydrogen sulphide burner that fires into the furnace, wherein the burner comprises a main passage for combustion-supporting gas containing air, 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, wherein the outlets of the inner and outer tubes are so disposed that, in operation, essentially all mixing of hydrogen sulphide with oxygen and air takes place downstream of the distal end of the burner and wherein the outlets of the inner and outer tubes are also so juxtaposed and dimensioned as to enable there to be maintained in the furnace, in operation, a stable flame with at least one first high temperature first stage and at least one second lower temperature stage, the first stage being more remote than the second stage from a chosen area of the inner wall or walls of the furnace, the chosen area thereby being shielded from the first stage by the second stage, and the tubes are arranged in two groups, there being a first group of inner and outer tubes which in operation feed the first stage of the flame, and a second group of inner and outer tubes which in operation feed the second stage of the flame, the inner tubes in the first group being of greater internal diameter than the inner tubes in the second group.