A METHOD FOR DECREASING NITROGEN OXIDES OF A PULVERIZED COAL BOILER USING BURNERS OF INTERNAL COMBUSTION TYPE

摘要

A method for decreasing nitrogen oxides of a pulverized coal boiler using burners (2) of internal combustion type comprising: designing or changing all or part of burners of the pulverized coal boiler as internal combustion type burners (2), in which the ignition sources may be plasma generators (1) or ignition devices such as small oil guns etc., and the power thereof can be adjusted for controlling the ignition intensity in the burners (2). The burners (2) are interiorly divided into several stage combustion chambers (5) and are provided with pulverized coal concentrators (4) which do deep fuel staging in the burners (2). During the operation of the boiler, the ignition sources always keep in a working state, and the pulverized coal in the burners (2) is ignited stage by stage and is burnt in advance; decreasing the secondary air amount in the primary combustion zone (22) so that the primary combustion zone (22) is in a relatively strong reducing atmosphere and a high temperature and oxygen-deficient condition for inhibiting the generation of NOx is created; and supplying the remaining air from the upper of furnace of the boiler in the form of over-fire air, so that a deep air staging is carried out in the total furnace. Thus, the NOx generation of combustion can be effectively controlled on the premise of not decreasing the boiler efficiency.