纳米氧化锌在模拟煤气下吸附单质汞的实验研究

采用均匀沉淀法制备纳米氧化锌吸附剂,并采用BET、XRD、XPS等分析手段对其进行表征。在固定床吸附实验台上,研究了吸附剂在N₂和模拟煤气气氛下对单质汞的吸附特性,分析气体成分对纳米氧化锌脱汞性能的影响。结果表明,纳米氧化锌在纯N₂气氛下的脱汞效率较低,以物理吸附为主;H₂S的加入可以显著提高纳米氧化锌对汞的吸附,停止通入H₂S后,脱汞效率仍能维持较长时间;CO和H₂通过促进纳米氧化锌脱硫进而促进对汞的脱除。随着温度的提高,纳米氧化锌表面形成的单质硫逐渐减少,抑制了吸附剂对单质汞的吸附脱除。

Elemental mercury removal from syngas by nano-ZnO sorbent

Nano-ZnO sorbents synthesized by a homogeneous precipitation method were characterized by BET (Brunauer-Emmett-Teller), XRD (X-ray diffraction) as well as XPS (X-ray photoelectron spectroscopy) analysis. The adsorption of elemental mercury by nano-ZnO under nitrogen and simulated gas atmosphere was studied on a bench-scale fixed-bed apparatus. The effect of various gases on Hg⁰ removal performance by nano-ZnO was analyzed. The results show that the mercury removal efficiency of the nano-ZnO is relatively poor in nitrogen atmosphere. The presence of H₂S promotes the Hg⁰ removal by nano-ZnO observably and the mercury removal efficiency can be maintained for a long time even after stopping pass into H₂S. The presence of CO and H₂ promotes the Hg⁰ removal because of desulfurization effect of nano-ZnO. As the temperature increases, the formation of elemental sulfur in the surface of the nano-ZnO decreases, which can suppress the removal of Hg⁰ by sorbent.