Method for combustion of a low-grade fuel

A method for combustion of a fuel, the method comprising the steps of:

• using an existing air burner (1), which air burner (1) comprises a first supply opening (5) for fuel and a second supply opening (7) for air, which first and second supply openings (5,7) open out into a combustion zone (3),
• supplying a gaseous low-grade fuel with a lower heating value (LHV) of less than 7.5 MJ/Nm3 through the second supply opening (7) for air,
• supplying an oxidant comprising at least 85 percent by weight oxygen to the combustion zone (3) through a supply device for oxidant, and causing the gaseous low-grade fuel to be combusted with the oxidant in the combustion zone (3),
• wherein the supply device for oxidant is caused to be arranged so that oxidant is supplied wholly or partially through the existing first supply opening (5) for fuel in the air burner (1).

A method for combustion of a fuel, the method comprising the steps of:

• using an existing air burner (1), which air burner (1) comprises a first supply opening (5) for fuel and a second supply opening (7) for air, which first and second supply openings (5,7) open out into a combustion zone (3),
• supplying a gaseous low-grade fuel with a lower heating value (LHV) of less than 7.5 MJ/Nm3 through the second supply opening (7) for air,
• supplying an oxidant comprising at least 85 percent by weight oxygen to the combustion zone (3) through a supply device for oxidant, and causing the gaseous low-grade fuel to be combusted with the oxidant in the combustion zone (3),
• wherein the combustion reaction between oxidant and the low-grade fuel is caused to heat an industrial furnace (14).