煤和污泥燃烧和气化过程中汞析出行为的研究

固体燃料和固体废物在燃烧和气化过程中的汞排放问题在全球已经受到广泛关注。该文首先选取3个煤种和3种干城市污泥作为样本，通过热重(TG)实验了解汞在燃烧和气化过程中的基本析出行为。然后选取一个污泥样在滴管炉里燃烧，研究汞在接近实际燃烧状况下的析出行为。通过热平衡计算预测了在和实验相同条件下汞析出的变化趋势。结果表明，污泥燃烧过程中汞的析出行为受到污泥中硫和固定碳含量的抑制，煤燃烧过程中汞的析出行为受到煤中固定碳含量和Cl含量的重要影响。另外，因为单质汞在还原性气氛下极易形成，在气化过程中，即使是低温汞也很快析出。

Study on Behaviors of Mercury Emission During Combustion/Gasification Processes of Coal and Sludges

Mercury emissions from combustion/ gasification processes of solid fuels and wastes have been concerned worldwide. First, thermo-gravimetric(TG) experiments were carried out to understand fundamentals of mercury evolution behaviors under the combustion and gasification conditions, using three types of coal and three types of dried sewage sludge as the samples. Then, one sample was burnt in an electric drop tube furnace to study the evolution behavior of mercury in semi-practical combustion processes. Moreover, chemical equilibrium calculation predicted the tendency of mercury evolution under the same experimental conditions. The results obtained show that sulfur content in the fuels inhibits the evolution behaviors of mercury during sludge combustion. For coal, while, the fixed carbon content and Cl concentration in the coal play an important role for the mercury evolution. Under the gasification condition, however, mercury evolves quickly because the elemental mercury is easily formed in the low temperature.