Experimental Study On NO,N₂O And SO₂ Simultaneous Emissions During Fluidized Bed Combustion

The circulating fluidized bed combustion technology has the advantages of wide combustion adaptability,high combustion efficiency,high desulfurization efficiency and low NOx emission.However,there is still a lack of experimental results of the simultaneous emission characteristics of NO,N₂O and SO₂ during the fluidized combustion process.In this paper,the simultaneous emission characteristics of NO,N₂O and SO₂ during the fluidized combustion process are studied by experimental methods,which provides guidance for the design and actual operation of circulating fluidized bed boilers.The main research work is as follows:?1?The effects of operating parameters on the simultaneous emission characteristics of lignite,bituminous and anthracite were studied.A mini-scaled fluidized bed experimental system was set up to investigate the effects of excess air ratio,combustion temperature,Ca/S ratio,and O/N mass ratio on the simultaneous emission characteristics of NO,N₂O and SO₂.The results showed that under the conditions of combustion temperature of 750°C,850°C,900°C,950°C,with the increase of excess air ratio,the NO and N₂O emissions increased,SO₂ emissions increased first and then decreased.The highest emission of SO₂ was reached at the excess air ratio of 1.0.With the increasing combustion temperature,the NO and SO₂emissions increased,and the N₂O emissions decreased.N₂O emissions decreased to zero when the combustion temperature rised to 950?.Calcium carbonate would affect the simultaneous emission characteristics of NO,SO₂ and N₂O.Under different combustion temperatures,the desulfurization efficiency increased as the excess air ratio increased.Calcium carbonate promoted the formation of NO and inhibited the formation of N₂O.The NO emission was positively correlated with the O/N mass ratio,and the N₂O emission was negatively correlated with the O/N mass ratio,and the empirical formulas of NO,SO₂ and N₂O emission concentrations versus excess air ratio and temperature were obtained.?2?The effects of operating parameters on the simultaneous emission characteristics of lignite were studied.A 30kW CFB experimental system was set up in order to investigate the effects of excess air ratio and O/N mass ratio on the simultaneous emission characteristics of NO,N₂O and SO₂.The results showed that at the combustion temperature of 900°C,NO,N₂O emissions increased and SO₂emissions decreased with the increasing excess air ratio.NO emissions were positively correlated with O/N mass ratio,and N₂O emissions were negatively correlated with O/N mass ratio.