Experimental study on low NOx emission using blast furnace gas reburning and industrial application in stoker boiler

In order to get some useful information on reforming one stoker boiler with the capacity of 75t/h by using gas reburning technology, the effect of some key factors such as stoichiometric coefficient, residence time, reburning temperature and reburning gas - coal heat ratio on NOx emission characteristics was studied in a one-dimensional experimental system. The results showed that the longer residence time of flue gas in reburning zone of furnace will get lower NOx emission, there exists an optimum residence time of flue gas in reburning zone, the optimum residence time is around 0.8s. There also exists an optimum stoichiometric ratio of air in reburning zone of furnace, the value of that is around 1.0. The removing rate of NOx increases with both increasing feeding rate of reburning gas and increasing reburning temperature. The gas reburning technology has been successfully used during reforming an stoker boiler with the capacity of 75t/h, the NOx removing efficiency was over than 50%.