A method and apparatus for heating a furnace using a burner system having first and second burner assemblies, each including a burner and a regenerative media bed, the method including operating the first burner assembly in a firing mode and the second burner assembly in a regeneration mode, switching the first burner assembly from the firing mode to the regeneration mode and the second burner assembly from the regeneration mode to the firing mode, and operating the second burner assembly in the firing mode and the first burner assembly in the regeneration mode. The burner assembly in the firing mode may be fired in either a first operating mode where the burner is supplied with preheated low calorific fuel and the burner is supplied with oxidizing gas or a second operating mode where the burner is supplied with preheated oxidizing gas and the burner is supplied with high calorific fuel.

The burner, which comprising an air supply pipe, fuel supply pipe attached to a central burner tube, which is terminated by the front face on the side of the supply pipe whereas in the front face a support tube is fixed, on which a burner head at the burner's output is mounted, the burner head is provided with nozzles arranged in a circle near to the inner perimeter of the burner head and forming the primary stage of the burner, and further the burner head is provided with angled grooves on the outer perimeter, which form the secondary stage of the burner, and further the whirler with its inner perimeter is arranged onto central burner tube at its outlet end, and the whirler's surface has conical shape extending outwardly and the whirler's surface openings, arranged in a circle are provided.