在四喷嘴对置式气流床气化炉中,考察了水煤浆在不同氧碳比气化条件下HCN、NH3、NO和N2的轴径向浓度。结果表明:氮污染物(HCN、NH3、NO)在喷嘴平面处即产生并浓度最高,其主要来源于煤粒快速热解时析出的挥发分,远离喷嘴平面时三者浓度大幅降低并大多转化为N2,且氧碳比增高有利于N2的生成,气化室出口处浓度N2〉HCN〉NH3〉NO;流场分布使气化室出口附近径向浓度基本一致,而其上部各平面位置靠近炉壁处浓度较低;煤浆中的适量水分有利于HCN和NH3生成,但过量水分不利于挥发氮析出,使HCN、NH3和NO生成量降低。
Various axial and radial concentrations of HCN,NH3,NO and N2 were measured during the gasification of coal water slurry(CWS) in a laboratory opposed multi-burner gasifier.The results showed that the majority of nitrogen pollutants(HCN,NH3 and NO) came from the release of volatile nitrogen of coal during the rapid heating process of devolatilization.The maximum concentrations of nitrogen pollutants were produced at the nozzle plane and decreased away from the plane;moreover,the ordering in the aft-region was N2〉HCN〉NH3〉NO.Increase of O2/C ratio tended to favor the formation of N2.Flow field distribution led to uniform radial concentrations at the exit and low concentrations near the side-wall in other axial positions.A proper amount of water in CWS tended to favor the formation of HCN and NH3.However,the introduction of excessive steam played a role in restraining the release of volatile nitrogen and reducing the concentrations of HCN,NH3 and NO.