城市生活垃圾焚烧中铅形态转化的热力学平衡

Thermodynamic equilibrium analysis of lead partitioning during MSW incineration

采用热力学平衡计算方法,研究城市生活垃圾焚烧过程中焚烧温度、S,Cl以及空气过量系数等影响因素间的交互作用对Pb的形态转化的影响,并考察不同焚烧工况下,CaO和SiO_2对焚烧中Pb的吸附效果。研究结果表明:不同焚烧气氛下S和Cl对焚烧中Pb的形态转化特性影响较大;在氧化性气氛下,S可抑制焚烧中Pb的挥发,Cl可促进Pb的挥发;在还原性气氛下,S和Cl均能较好地促进Pb的挥发。焚烧中S与Pb的亲和性比Cl与Pb的亲和性强;Na与S,Cl的亲和性比Pb的好,Na在一定程度上抑制了S和Cl对Pb作用。CaO对Pb的吸附效果较差,但可有效地减弱S和Cl对Pb的影响;SiO_2可在较大的温度范围内有效吸附焚烧中的Pb,垃圾中的Cl会降低SiO_2的吸附效果,S对SiO_2的吸附效果影响不大。

Thermodynamic equilibrium calculations were performed to investigate the effects of the interactions of incineration temperature, sulphur, chloride and excess air coefficient on the partitioning of lead during municipal solid waste（MSW） incineration. The adsorption of lead was also studied by adding CaO, Al2O3 and SiO_2 into the incineration system. The results show that sulphur and chloride in the waste have different effects on the partitioning of lead during the waste incineration in different atmospheres. Sulphur can depress the evaporation of lead under oxidative condition,while chloride has the opposite effect. Both sulphur and chloride can promote the volatilization of lead effectively under reductive condition. The affinity of sulphur with lead is much stronger than that of chloride. The effects of sulphur and chloride can be depressed by Na which has much stronger affinity with sulphur and chloride than lead. CaO has a weak effect on the adsorption of lead, while it can effectively depress the effect of sulphur and chloride. SiO_2 can effectively adsorb lead of MSW in a large temperature range, and chloride of MSW will weaken the adsorption of SiO_2, while sulphur has little effect on the adsorption.