A mobile heating device operated with liquid fuel is provided, having: a combustion chamber (2) comprising a combustion air inlet (3), wherein the combustion chamber adjacent to the combustion air inlet (3) comprises a widening portion (20) the cross-section of which widens with increasing distance from the combustion air inlet (3) and in which in operation combustion air and fuel are converted in a flaming combustion; a fuel supply which is arranged such that fuel is supplied into the widening portion (20); and an air guide device (6) being adapted to feed combustion air into the widening portion (20) with a flow component directed in the circumferential direction such that an axial recirculation region (RB) forms in the widening portion (20) in which gases flow in the direction towards the combustion air inlet (3) oppositely to a main flow direction (H). The combustion chamber (2) is fluidically sectioned into a primary combustion zone (PZ) and a secondary combustion zone (SZ). The primary combustion zone (PZ) comprises the widening portion (20) and the recirculation region (RB). The secondary combustion zone (SZ) is provided with a secondary combustion air inlet (23) in such a manner that a higher air-fuel ratio λ than in the primary combustion zone (PZ) forms in the secondary combustion zone (SZ).

A burner for a rotary kiln comprising an elongated tubular body (6) having a longitudinal axis (L) and a discharge end (7) adjacent a combustion zone comprising a flame, at least one fuel supply pipe for transporting and ejecting fuel through a fuel pipe outlet (10) at the discharge end (7), the fuel being alternative fuel or a mixture of alternative fuel and fossil fuel, and at the discharge end (7), a number of high speed primary air jet outlets for ejecting primary air and being arranged, when seen towards the discharge end, along a closed line, such as a circle, outwardly of the fuel outlet (10) and surrounding the fuel outlet,
wherein at least one of the primary air outlets and preferably a number of the primary air outlets comprise a single orifice outlet or a multiple orifice outlet forming a flat jet air outlet (11) having a major axis and a minor axis and being configured to eject a flat jet air stream (13) having a flat fan pattern with a predetermined fan angle v.

A scalable pulse combustor that can be deployed as the heat exchanger in high efficiency, low NOx condensing boilers, water heaters and steam generators is provided. The combustor generally comprises an annular burner coil with a burner flange for accommodating the nozzle of a conventional burner/blower fitted into the central aperture thereof; a spaced-apart opposite annular spreader coil with a heat exchange hub fitted into the central aperture thereof; and a plurality of annular intermediate coils. Each of the burner, spreader and intermediate coils are preferably formed of spiral wound stainless steel tubing, with each winding directly abutting the preceding winding so as to create an annular wall. The heat exchange hub functions as a secondary heat exchanger with its own independently controllable coolant flow.

A burner for a rotary kiln comprising an elongated tubular body (6) having a longitudinal axis (L) and a discharge end (7) adjacent a combustion zone comprising a flame, at least one fuel supply pipe for transporting and ejecting fuel through a fuel pipe outlet (10) at the discharge end (7), the fuel being alternative fuel or a mixture of alternative fuel and fossil fuel, and at the discharge end (7), a number of high speed primary air jet outlets for ejecting primary air and being arranged, when seen towards the discharge end, along a closed line, such as a circle, outwardly of the fuel outlet (10) and surrounding the fuel outlet,
wherein at least one of the primary air outlets and preferably a number of the primary air outlets comprise a single orifice outlet or a multiple orifice outlet forming a flat jet air outlet (11) having a major axis and a minor axis and being configured to eject a flat jet air stream (13) having a flat fan pattern with a predetermined fan angle v.

A combustion apparatus includes a housing and injection members. The housing has a bottom wall and side walls which enclose a combustion chamber having an opening at the top. The injection members are arranged on two side walls opposite each other and include at least one first injector and at least one second injector. The first injector supplies to the combustion chamber a mixture having a first-part oxidant and a combustible gas, with the volume percentage of the combustible gas in the mixture being greater than an upper combustion limit of the combustible gas. The second injector supplies a second-part oxidant to the combustion chamber. The total amount of the first-part oxidant and the second-part oxidant supplied to the combustion chamber reach stoichiometric balance with the amount of the combustible gas supplied to the combustion chamber. The combustion apparatus can produce short flames with high safety and good stability.