Process burner for combustion of a plurality of fuel gases with a gaseous auxiliary medium, wherein one of the fuel gases comprises carbon monoxide, comprising a. a first fuel gas unit for introducing a first fuel gas comprising a first fuel gas conduit and a first fuel gas nozzle, wherein the first fuel gas conduit comprises a first fuel gas inlet and a first fuel gas outlet, wherein the first fuel gas inlet is in fluid connection with a first fuel gas source and the first fuel gas outlet is connected to the first fuel gas nozzle; b. a second fuel gas unit for introducing a second fuel gas comprising a second fuel gas conduit and a second fuel gas nozzle, wherein the second fuel gas conduit comprises a second fuel gas inlet and a second fuel gas outlet, wherein the second fuel gas inlet is in fluid connection with a second fuel gas source, wherein the fuel gas from the second fuel gas source comprises at least carbon monoxide and the second fuel gas outlet is connected to the second fuel gas nozzle; c. an auxiliary media unit comprising an auxiliary media conduit and a burner plenum, wherein the auxiliary media conduit comprises an auxiliary media inlet and an auxiliary media outlet, wherein the auxiliary media inlet is in fluid connection with an auxiliary media source and the auxiliary media outlet is connected to the burner plenum; d. a burner tile, wherein the burner tile adjoins the burner plenum and the burner tile has a refractory surface, wherein the refractory surface adjoins a combustion zone of the process burner, wherein the burner tile and the combustion zone are configured for combustion of the first fuel gas and the second fuel gas with the auxiliary medium, wherein the fuel gas from the second fuel gas source comprises at least 50 mol% of carbon monoxide, the first fuel gas nozzle for introducing the first fuel gas is arranged inside the combustion zone and the second fuel gas nozzle for introducing the second fuel gas is arranged inside the auxiliary media unit. a. a first fuel gas unit for introducing a first fuel gas comprising a first fuel gas conduit and a first fuel gas nozzle, wherein the first fuel gas conduit comprises a first fuel gas inlet and a first fuel gas outlet, wherein the first fuel gas inlet is in fluid connection with a first fuel gas source and the first fuel gas outlet is connected to the first fuel gas nozzle; b. a second fuel gas unit for introducing a second fuel gas comprising a second fuel gas conduit and a second fuel gas nozzle, wherein the second fuel gas conduit comprises a second fuel gas inlet and a second fuel gas outlet, wherein the second fuel gas inlet is in fluid connection with a second fuel gas source, wherein the fuel gas from the second fuel gas source comprises at least carbon monoxide and the second fuel gas outlet is connected to the second fuel gas nozzle; c. an auxiliary media unit comprising an auxiliary media conduit and a burner plenum, wherein the auxiliary media conduit comprises an auxiliary media inlet and an auxiliary media outlet, wherein the auxiliary media inlet is in fluid connection with an auxiliary media source and the auxiliary media outlet is connected to the burner plenum; d. a burner tile, wherein the burner tile adjoins the burner plenum and the burner tile has a refractory surface, wherein the refractory surface adjoins a combustion zone of the process burner, wherein the burner tile and the combustion zone are configured for combustion of the first fuel gas and the second fuel gas with the auxiliary medium, wherein the fuel gas from the second fuel gas source comprises at least 50 mol% of carbon monoxide, the first fuel gas nozzle for introducing the first fuel gas is arranged inside the combustion zone and the second fuel gas nozzle for introducing the second fuel gas is arranged inside the auxiliary media unit.