A burner includes a generally cylindrical reactor chamber (1) including a housing (1′) having a proximal end (1p) and a distal end (1d). In the distal end of the reactor chamber (1) there is provided a catalyst (4). A fuel inlet (7) is provided in the proximal end of the reactor chamber. There are also a plurality of air inlets (22, 23; 24) arranged in the reactor wall at the proximal end. The inlets are configured to provide a rotating flow of the air injected into the reactor chamber. There is also provided a flow homogenizer (8; 30) extending over the cross-section of the reactor chamber at a position between the fuel inlet (7) and the catalyst (4).