Abstract: A process to prepare a synthesis gas comprising hydrogen and carbon monoxide comprises performing a partial oxidation on a methane comprising feed using a multi-orifice burner provided with an arrangement of separate passages, wherein the gaseous hydrocarbon having an elevated temperature flows through a passage of the burner, an oxidizer gas flows through a separate passage of the burner and wherein the passage for gaseous hydrocarbon feed and the passage for oxidizer gas are separated by a passage through which a secondary gas flows, wherein the secondary gas comprises hydrogen, carbon monoxide and/or a hydrocarbon.