污泥热解和气化过程中NO_x前驱物的释放特性

Release features of NO_x precursors during the pyrolysis and gasification of sewage sludge

利用固定床反应器对3种取自广州和武汉城市污水处理厂的污泥(GZ,LWZ和NTZH)进行了系统的热解和气化试验,采用傅里叶变换红外光谱仪(FT-IR)在线检测热解气体产物中的含氮组分,分析各种气相含N组分的释放规律.实验结果表明:GZ,LWZ和NTZH污泥热解释放大部分NO,NH3和HCN的温度范围分别为320～600,200～700和300～800℃;LWZ污泥热解过程中生成的NH3,HCN和NO量最多;Ar和O2混合气(O2体积分数为4%)气氛下气化时,GZ,LWZ和NTZH污泥NO开始快速生成的温度比热解时分别提高约200,400和250℃,NO的生成量分别为热解时的4.30,2.34和3.93倍;NH3开始快速生成的温度与热解时基本相同,NH3的生成量分别为热解时的67%,1.37倍和95%;HCN生成完成时的温度比热解时分别低约400,100和200℃,HCN的生成量分别为热解时的1.10倍,1.21倍和95%.

Three sewage sludge samples as GZ,LWZ and NTZH were pyrolyzed and gasified in a fixed-bed reactor.The nitrogenous components in the product gases were analyzed by Fourier transform infrared spectrometer（FT-IR）.The releasing regulation of the nitrogenous components in the product gases was analyzed.The experimental results show that most of the NO,NH3 and HCN were released during 320600,200700 and 300800 ℃,respectively.LWZ releases more NH3,HCN and NO than GZ and NTZH during pyrolysis.During sewage sludge gasification under mixture gas of Ar and O2（volume fraction is 4%）,the NOx precursors release temperature and concentration changeble compared with pyrolysis.The NO release temperature during gasification increased by about 200,400 and 250 ℃ than pyrolysis and the NO yields was 4.30,2.34 and 3.93 times of that generated in pyrolysis.The NH3 release temperature during gasification was nearly the same as that of pyrolysis and the NH3 yields was 0.67,1.37 and 0.95 times of that generated in pyrolysis.And the HCN release temperature during gasification decreased by 400,100 and 200 ℃ than that of pyrolysis,and the HCN yields was 1.10,1.21 and 0.95 times of that generated in pyrolysis.