METHOD OF REDUCING NITROGEN OXIDE EMISSIONS BASED ON PLASMA FLAME STABILISATION OF PULVERISED COAL FLOW AND DEVICE INTENDED FOR REALISATION THEREOF Russian patent published in 2009 - IPC F23D1/00 

FIELD: heating systems.

SUBSTANCE: invention refers to power engineering. Method of reducing nitrogen oxide emissions at flaring of pulverised coal in the boiler involves supply of pulverised coal mixture to the main burners with excess air factor α_b<1, ignition and firing of coal in furnace, as well as supply of the rest air required for complete coal firing to furnace above the main burners. In some burners (mainly not more than 10% of total number of the main burners) air-and-coal mixture is ignited with plasma. Burners of lower tier are equipped with plasmatrons. Plasma coal ignition is performed in additional burners and arranged in plane of lower tier of the main burners. Plasma coal ignition is performed in additional burners and located below arrangement plane of the main burners of lower tier. Plasma pulverised-coal burner includes thermochemical fuel treatment chamber the inner surface of which is cylinder-shaped, conduit for supplying pulverised coal mixed with air to that chamber, plasmatron installed on side surface of thermochemical fuel treatment chamber at its inlet part, connection pipe of thermochemical fuel treatment chamber, in which plasmatron is installed, and secondary air channel. The part of internal wall of thermochemical fuel treatment chamber, which is adjoined to connection pipe, is made in the form of flat surface and outlet edge of plasmatron is located in one and the same plane with this flat surface of internal chamber wall. At staged coal combustion in some burners there performed is plasma ignition of coal-and-air mixture flow prior to its being supplied to furnace. It allows to decrease excess air factor in burners at constant unburnt carbon and efficiency of boiler.

EFFECT: deeper reduction of nitrogen oxides and reduction of burner slagging is achieved.

5 cl, 5 dwg