Abstract: A pressurized fluidized bed burner with a pressurized container. The container is provided with an air-supply connection and accommodates a combustion chamber. The combustion chamber is provided with an air box to supply combustion air. A compressor and a preliminary air heater are accommodated in the air line leading to the pressurized container. The object is to exploit lost heat to heat the combustion air and to prevent the wall of the pressurized container from being exposed to additional thermal stress. The pressurized container has an air-extraction connection. The intake end of the preliminary air heater communicates with the air-extraction connection. Its outlet end communicates with the air box in the combustion chamber through an air line that extends through the pressurized container.