【摘要】 为研究垃圾焚烧过程中NaCl的迁移和转化,在管式炉中进行了模拟垃圾焚烧实验,结合扫描电镜–能谱分析(SEM-EDS)和热力学平衡模拟计算,分析了温度、停留时间、烟气中的水分和S等对氯化钠迁移转化的影响。研究结果表明,温度升高能促进NaCl蒸发和分解,从而增加氯在飞灰和烟气中的分布。在1000℃时焚烧12min后NaCl的迁移分布趋于稳定。SEM-EDS结果显示,800℃时NaCl以不规则的形态聚集在底渣基体表面;而1000℃时氯在底渣中扩散均匀,形成了半球状位错结构,飞灰中的氯为亚微米精细结构。热力学平衡计算表明,酸性氧化物Al2O3、SiO2与Na有很强的亲和力,能促进NaCl氧化分解生成HCl。烟气中的水分对Cl的迁移没有显著影响,水解的反应不易发生。烟气中的SO2和SO3能与NaCl反应生成Na2SO4促进其分解,且随温度降低促进效果越明显。更多还原

【Abstract】 In order to investigate the partitioning and speciation of NaCl during municipal solid waste(MSW) incineration the artificial waste was experimentally burned in a quartz tube furnace. The scanning electron microscope-energy dispersive X-ray(SEM-EDS) analysis and thermodynamic equilibrium calculation were performed to study morphological transformation of chlorine. The factors include temperature, retention time, moisture in the flue gas and sulfur content on the NaCl partitioning. The results showed that temperature can promote the NaCl evaporation and decomposition, thus can increase chlorine distribution in fly ash and flue gas. After burning 12?min at 1?000?℃ NaCl migration distribution tends to be stable in the experiments. The SEM-EDS results show that NaCl irregularly exists at the surface of slag substrate as the temperature is 800?℃; and as the temperature is 1?000?℃ the chloride diffuse in the bottom slag, forming the half ball dislocation structure, while the chlorine forms the submicron fly ash in the fine structure of the nucleus of condensation. Thermodynamic equilibrium calculation show that the acidic oxides, Al2 O3 and SiO2, have a strong affinity with Na, they can promote the oxidative decomposition of NaCl to generate HCl. The evident effect of moisture in flue gas on the NaCl partition-ing is not observed, as a result, hydrolysis reaction istoo difficult to occur. The SO2 and SO3 in the flue gas can react with NaCl to generate Na2 SO4, thus promotes its decomposi- tion, and with the decreasing temperature the effect of pro-moting is more obvious.更多还原