Pulverized coal combustion technology with preheating solid fuel in a circulating fluidized bed was used for the combustion test of ultra-low volatile carbon-based fuel.This paper first validated the feasibility and a...Pulverized coal combustion technology with preheating solid fuel in a circulating fluidized bed was used for the combustion test of ultra-low volatile carbon-based fuel.This paper first validated the feasibility and advantages of applying the combustion technology to this kind of fuel.The carbon-based fuel could achieve a stable preheating process in this test system.After the preheating,the apparent sensible heat of the fuel was significantly increased.This provided a necessary condition for the stable ignition and efficient combustion of the carbon-based fuel in the post-combustion chamber.The relative proportions of CO,H2,and CH4 in preheated coal gas were very low,and the effect of high-temperature coal gas at the entrance of the post-combustion chamber was greatly impaired,indicating that the combustion process in post-combustion chamber was mainly the combustion of preheated char.At the same time,the strong reducing atmosphere in the circulating fluidized bed also facilitated the reduction of fuel-nitrogen into N2,which resulted in low NOx emissions.On this basis,with the combination of preheating combustion technology and air-staging combustion technology,the NOx emissions had drastically decreased when the burnout air distribution position moved down or varied from a single-layer distribution to a multi-layer distribution system.The lowest original NOx emissions were 90.6 mg/m3(at 6%O2),and the combustion efficiency exceeded 97%,which ultimately achieved efficient and clean combustion of ultra-low volatile carbon-based fuel.展开更多
基金the support of the National Key Research and Development Program of China(2017YFB0602005)
文摘Pulverized coal combustion technology with preheating solid fuel in a circulating fluidized bed was used for the combustion test of ultra-low volatile carbon-based fuel.This paper first validated the feasibility and advantages of applying the combustion technology to this kind of fuel.The carbon-based fuel could achieve a stable preheating process in this test system.After the preheating,the apparent sensible heat of the fuel was significantly increased.This provided a necessary condition for the stable ignition and efficient combustion of the carbon-based fuel in the post-combustion chamber.The relative proportions of CO,H2,and CH4 in preheated coal gas were very low,and the effect of high-temperature coal gas at the entrance of the post-combustion chamber was greatly impaired,indicating that the combustion process in post-combustion chamber was mainly the combustion of preheated char.At the same time,the strong reducing atmosphere in the circulating fluidized bed also facilitated the reduction of fuel-nitrogen into N2,which resulted in low NOx emissions.On this basis,with the combination of preheating combustion technology and air-staging combustion technology,the NOx emissions had drastically decreased when the burnout air distribution position moved down or varied from a single-layer distribution to a multi-layer distribution system.The lowest original NOx emissions were 90.6 mg/m3(at 6%O2),and the combustion efficiency exceeded 97%,which ultimately achieved efficient and clean combustion of ultra-low volatile carbon-based fuel.
文摘针对选择性催化还原(selective catalytic reduction,SCR)脱硝系统反应过程复杂,在工况变化时存在非线性、大惯性和强干扰性的特点,难以建立准确的出口NO_x排放浓度模型。利用核偏最小二乘法具有解决变量众多且存在严重相关的非线性工业过程建模的优点,首先引入正交信号校正(orthogonal signal correction,OSC)对相空间重构后的样本进行预处理,剔除与建模无关的信息;然后利用组合核偏最小二乘法(combination kernel partial least squares,CKPLS)具有较好的学习能力和泛化能力的特点,提出OSC-CKPLS方法提高模型性能;最后采用滑动窗口更新,并反馈补偿修正模型。对2个标准数据集进行仿真,分别验证CKPLS、OSC和OSC-CKPLS能够提高模型性能;并对SCR脱硝系统现场数据验证了本文方法的有效性。
