A burner comprises a nozzle main body (7) which is installed along a central axis of a throat (4) provided on a furnace wall (3) and comprises an inner nozzle (11) in which an auxiliary combustion air (24) flows and an outer nozzle (9) which is provided on an outer side and concentrically with the inner nozzle and in which a pulverized coal mixed flow (18) obtained by mixing a carrying medium with a pulverized coal flow, a wind box (5) for accommodating the nozzle main body, a secondary air regulator (8) accommodated in the wind box and provided at a tip portion of the nozzle main body, an auxiliary combustion air intake pipe (23) for introducing a combustion air as an auxiliary combustion air (22) into the inner nozzle from the wind box, a pulverized coal flow supply pipe (16) for introducing a pulverized coal mixed flow into the outer nozzle, and an oxygen-containing gas supply pipe (17) for supplying an oxygen-containing gas (19) to the pulverized coal mixed flow and raising the oxygen concentration in the pulverized coal mixed flow.

The present invention relates to a pulverized coal fired boiler with wall-attachment secondary air and grid overfire air. Primary burners including primary air spouts, secondary air spouts and close coupled overfire air spouts arranged at intervals along the height direction of a hearth are arranged on four corners of the hearth. Two-way wall-attachment secondary air spouts and one-way wall-attachment secondary air spouts are arranged from bottom to top in a primary combustion zone where the primary burners are located. One-way wall-attachment secondary air spouts are arranged in a reduction zone between the primary burners and the top overfire air spouts, and grid overfire air spouts are arranged in a burnout zone where the overfire air is supplied. By adopting the pulverized coal fired boiler with wall-attachment secondary air and grid overfire air according to the present invention, the NO amount generated in the hearth is reduced, the NO reduction rate along a flame is improved, the coke burnout rate is improved, less coke which is not burnt out enters into the burnout zone, slagging on the water-cooled wall is reduced, and ultralow emission of NOx may be realized on the premise that the combustion efficiency is not reduced, slag is not agglomerated in the hearth and the flue gas temperature deviation is small.

The present invention relates to a pulverized coal fired boiler with wall-attachment secondary air and grid overfire air. Primary burners including primary air spouts, secondary air spouts and close coupled overfire air spouts arranged at intervals along the height direction of a hearth are arranged on four corners of the hearth. Two-way wall-attachment secondary air spouts and one-way wall-attachment secondary air spouts are arranged from bottom to top in a primary combustion zone where the primary burners are located. One-way wall-attachment secondary air spouts are arranged in a reduction zone between the primary burners and the top overfire air spouts, and grid overfire air spouts are arranged in a burnout zone where the overfire air is supplied. By adopting the pulverized coal fired boiler with wall-attachment secondary air and grid overfire air according to the present invention, the NO amount generated in the hearth is reduced, the NO reduction rate along a flame is improved, the coke burnout rate is improved, less coke which is not burnt out enters into the burnout zone, slagging on the water-cooled wall is reduced, and ultralow emission of NOx may be realized on the premise that the combustion efficiency is not reduced, slag is not agglomerated in the hearth and the flue gas temperature deviation is small.

A steam generating system includes a furnace, a nozzle tip assembly for pulverized coal and primary air as well as means for conveying secondary air in the furnace. The nozzle according to the invention comprises a nozzle body (3) and several channels (5) being connected with the nozzle body, the channels are diverging from each other. At the exit faces (17) of the channels obstructions (13) are disposed to induce huge turbulences of the primary air when entering the furnace. Due to these turbulences the primary air and the entrained coal are mixed very well before being combusted in the furnace. This results in a better more effective combustion with reduced NOx-emissions.

A steam generating system includes a furnace, a nozzle tip assembly for pulverized coal and primary air as well as means for conveying secondary air in the furnace. The nozzle according to the invention comprises a nozzle body (3) and several channels (5) being connected with the nozzle body, the channels are diverging from each other. At the exit faces (17) of the channels obstructions (13) are disposed to induce huge turbulences of the primary air when entering the furnace. Due to these turbulences the primary air and the entrained coal are mixed very well before being combusted in the furnace. This results in a better more effective combustion with reduced NOx-emissions.

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 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).

An inward-firing combustion burner, includes a burner casing configured to receive a fuel-air mixture at a burner inlet and to provide hot combustion gas at a burner output, a combustion substrate disposed within the burner casing, the substrate having a shape comprising at least a semi-cone or a flat surface or equivalent shape, having a substrate porosity defined by a plurality of pores, and having a substrate inner surface and a substrate outer surface, the substrate configured to receive the fuel-air mixture at the outer surface of the substrate, the fuel-air mixture passing through the pores at a mixture flow rate from the substrate outer surface toward the substrate inner surface, and the burner configured such that, in operation, the fuel-air mixture ignites near the plurality of pores to form a respective plurality of flamelets, each flamelet corresponding to one of the pores.

An inward-firing combustion burner, includes a burner casing configured to receive a fuel-air mixture at a burner inlet and to provide hot combustion gas at a burner output, a combustion substrate disposed within the burner casing, the substrate having a shape comprising at least a semi-cone or a flat surface or equivalent shape, having a substrate porosity defined by a plurality of pores, and having a substrate inner surface and a substrate outer surface, the substrate configured to receive the fuel-air mixture at the outer surface of the substrate, the fuel-air mixture passing through the pores at a mixture flow rate from the substrate outer surface toward the substrate inner surface, and the burner configured such that, in operation, the fuel-air mixture ignites near the plurality of pores to form a respective plurality of flamelets, each flamelet corresponding to one of the pores.

The invention provides a combustion apparatus and a combustion method capable of ashing matter to be combusted inside a combustion chamber efficiently without providing a device such as an unburned combustibles measurement device and without varying the direction of injection of air into the combustion chamber. The powder fuel combustion apparatus 1 includes a fuel supply device 10, a primary combustion chamber 20, a secondary combustion chamber 50, an air supply/ash discharge device 32, and a cyclone dust collector 60. An inclined portion 23a is formed at a bottom portion 23 of the primary combustion chamber 20, and the inclined portion 23a includes bottom portion air supply ports 31 and an air supply/ash discharge device 32. The air supply/ash discharge device 32 includes a bottom portion air injection nozzle 34 and an ash delivery device 35. The bottom portion air injection nozzle 34 has upper and lower ends opened, and a plurality of injection ports 34a through which air is injected are formed on a side surface. During combustion of the powder fuel F, air having a strong wind pressure is injected through the bottom portion air injection nozzle 34 either regularly or irregularly to agitate the powder fuel F and achieve a good combustion state.