固体吸附剂控制燃煤重金属排放的实验研究

在滴管炉上进行了烟煤添加固体吸附剂的燃烧实验研究了硫酸钙、石灰石、铝土矿3种吸附剂对重金属元素Pb、Cd、Cu、Co、Ni排放的控制,并采用形态逐级提取法,将排放颗粒物中重金属分为吸附态、离子可交换态、碳酸盐结合态、硫酸盐结合态和残渣态从粗粒灰渣及细微粒子中重金属元素含量的分布和细微粒子中残渣态稳定形态含量增加2个方面说明添加吸附剂对煤中重金属的排放具有一定的捕获力.对不同的重金属,由于吸附剂本身物理化学特性的差异,所表现出的吸附能力也各不相同.硫酸钙对Pb、Cd、Cu的排放有控制作用;石灰石对Pb、Cd、Cu、Nj的排放有控制作用;铝土矿对5种重金属元素的排放都有控制作用吸附剂粒径越小,对重金属的吸附效果越好.

Effects of Solid Adsorbents on the Emission of Heavy Metals During Coal Combustion

Experiments were carried out on laboratory-scale pulverized coal combustion with different adsorbents. Three solid adsorbents (calcium sulfate,limestone and bauxite) were used to control the emission of heavy metals (Pb,Cd,Cu,Co,Ni) during coal combustion. Sequential extraction procedure was developed for partitioning of metals species in coal ash into five fractions: absorbable metals, exchangeable metals, metals bound to carbonate, metals bound to sulfate, residual metals. The adsorbents showed a certain adsorptive ability to heavy metals, and different adsorbent had different ability. It can be proved from the distribution of heavy metals between coarse ash residues and fine particles and also from the increment of stable speciation of heavy metals in fine particles. Calcium sulfate was effective sorbent for removal of Pb, Cd and Cu, limestone for removal of Pb, Cd, Cu, Ni, and bauxite for removal of these five heavy metals. Fine adsorbents have higher adsorptive ability than coarse adsorbents.