硫化氢对活性炭脱除单质汞的影响

H₂S是煤气中的含硫成分,活性炭能否催化氧化煤气中的H₂S形成活性硫,以促进H₂S和Hg⁰的协同脱除是值得研究的。 本文首先通过程序升温脱附和热力学分析了低温情况下H₂S对活性炭脱除Hg⁰的影响。 在较低吸附温度130 ℃下,H₂S不仅不能作为硫源,还使活性炭对Hg⁰的吸附显著减弱,这主要是由于H₂S对活性炭表面的吸附氧的消耗以及H₂S对含氧官能团的氧的取代反应造成的。 在此基础上,进一步研究了高温下H₂S对活性炭的影响,高温也不能使活性炭有效渗入单质硫。 所以无论低温还是高温情况下,利用H₂S作为硫源使Hg⁰以HgS的形式脱除并不是活性炭脱汞的可行手段。 本文揭示了较宽的温度范围内H₂S对单纯的活性炭脱除Hg⁰的影响机理,能为用于煤气脱汞的活性炭的设计以及作为负载时机理研究提供支持作用。

Effect of Hydrogen Sulfur on the Removal of Elemental Mercury with Activated Carbon

H₂S is a component with sulfur in coal gas and it is worth studying whether activated carbon can catalyze the H₂S in coal gas to form active sulfur, so as to promote the synergistic removal of H₂S and Hg⁰. In this paper, the mechanism of H₂S influence on the removal of Hg⁰ from activated carbon was analyzed by temperature programmed desorption method and thermodynamics. H₂S significantly weakened the adsorption of activated carbon on Hg⁰ in low temperature, which may be caused by the consumption of adsorbed oxygen on the surface of activated carbon and the substitution of oxygen in oxygen containing functional groups by H₂S. Then the feasibility of H₂S in coal gas to remove Hg⁰ and H₂S in high temperature was discussed. High temperature sulfuration cannot effectively sulfurize activated carbon with active sulfur. Therefore, mercury removal in the form of HgS with H₂S as a sulfur source is not a feasible method by activated carbon. The mechanism revealed here in on the influence of H₂S on Hg⁰ removal from pure activated carbon provides the guidance for designing activated carbon for gas mercury removal.