REDUCING SYSTEM OF NOX

摘要

A nitrogen oxide reducing system is provided to reduce nitrogen oxide caused due to lowering of the temperature of air, by lowering the temperature of door to be supplied to a burner and pre-heating the temperature of water to be supplied to a boiler through the waste heat generated during operation of the boiler. A nitrogen oxide reducing system includes a boiler(1), a burner(2), an economizer(6), a steam air heater(7), a stack(4), and a water spray unit(8). The burner heats water by transferring combustion heat to the boiler. The economizer is arranged in an exhaust gas passage(1a) of the boiler, and heats water through heat exchange between the high temperature exhaust gas discharged from the boiler and water supplied to the boiler. The steam air heater pre-heats outdoor air supplied to the burner by heat of steam. The stack discharges exhaust gas from the boiler to the atmosphere. The water spray unit lowers the temperature of flame by spraying water to flame in the burner.