This reduction, by recombustion, nitrogen oxides present in the fumes from a primary combustion completed in a furnace, and an installation for implementing it.

摘要

The reduction of oxides of nitrogen contained in furnace smoke is carried out by recombustion of the smoke, using a secondary fuel injected into a recombustion zone in at least two jets at relatively high and relatively low pressure respectively. The low-pressure jet is situated outside and concentrically with the high-pressure jet. The secondary fuel is a gas at a pressure of a few millibars to a few hundred millibars for the low pressure jet, and a few hundred millibars to a few bars to the high-pressure one. The pressure and flow of the gas in the two jets are regulated according to the dimensions of the recombustion zone and the characteristics of the smoke. The recombustion zone is also subjected to acoustic waves at a frequency of below some 32 Hz. The procedure is carried out in a recombustion zone (B) fed with secondary fuel through two coaxial inlets (2,2') equipped with pressure regulators (4,5). One wall of the recombustion zone is equipped with an acoustic wave generator (6) to homogenise the mixture inside the zone.