改性水滑石对城市生活垃圾燃烧的脱氯研究

Study on the chlorine removal characteristics and combustion behaviors of municipal solid waste with modified Mg-Al layered double hydroxide

城市生活垃圾(MSW)分别与Mg-AL水滑石(LDH)和改性LDH混合,在管式炉中燃烧。利用热重分析仪(TGA)和傅里叶变换红外光谱(FTIR)研究改性LDH对MSW的燃烧行为的影响,用扫描电镜(SEM)分析不同燃烧阶段燃烧产物的表面形貌。结果表明,随着温度的升高,改性LDH的脱氯率呈先上升后下降趋势,在700℃时达到最大值。与MSW和LDH的共混物相比,MSW和改性LDH的共混物的燃烧特性和着火稳定性较差,但是在相同条件下改性LDH的脱氯率远远高于LDH,更适合用作脱氯剂。考虑脱氯率、综合燃烧特性、着火稳定性、经济性、脱氯剂利用率等,改性LDH的适宜比例为30%~40%。

The municipal solid waste(MSW)combustion were respectively fully mixed with Mg-Al layered double hydroxides(LDH)and modified LDH and burned in a tubular furnace.Additionally,the combustion behaviors of MSW with modified LDH was studied by using a thermogravimetric analyzer(TGA)combined with Fourier transform infrared spectrometer(FTIR).The surface shapes of the blends at different stages of the combustion process were analyzed by scanning electron microscope(SEM).The results show that the dechlorination rate of modified LDH experiences uptrend firstly,following by an obvious decrement with the increase of temperature,and reaches the maximum value at 700℃.The blends of MSW and modified LDH have worse combustion characteristics and worse ignition stability than those of MSW and LDH.However,under the same conditions,the dechlorination rate of modified LDH is much higher than that of LDH,so it is more suitable to be used as dechlorination agent.Considering the dechlorination rate,comprehensive combustion characteristics,ignition stability,economy and utilization rate of dechlorination agent,the appropriate proportion of modified LDH should be between 30%and 40%.