复杂烟气条件下太西活性焦脱除Hg0的实验研究

为了解复杂烟气条件下活性焦吸附剂的脱汞特性,利用汞渗透管和主要气体成分模拟复杂烟气,在实验室规模的固态吸附剂汞吸附效能测定系统上,进行了太西活性焦吸附单质汞的实验研究,并采用FT-IR对活性焦表面进行了光谱表征。结果表明,在活性焦表面存在各种含氧官能团;在CO₂/N₂/O₂/SO₂/Hg⁰烟气体系中,当SO₂加入量为400、855、1 520 mL/m³时,出口汞浓度分别为36、43、48 μg/m³,SO₂对系统吸附Hg⁰的能力有抑制作用;在CO₂/N₂/O₂/NO/Hg⁰烟气体系中,较低浓度的NO对Hg⁰脱除有抑制作用,而高浓度值的NO抑制作用减弱;在CO₂/N₂/O₂/NO/SO₂/Hg⁰烟气体系下,提高NO浓度对Hg⁰脱除有一定的促进作用,而提高SO₂浓度初期促进汞的脱除,后期则表现为抑制作用。

Experimental study on mercury removal by Taixi activated coke under complex atmosphere of flue gases

In order to clarify the adsorption characteristic of activated coke under complex atmosphere of flue gases, a series of tests were conducted with a bench-scale fixed bed reactor. The simulated flue gas was prepared by mixing main composition of flue gas with mercury vapors generated through permeation tube. The surface properties were characterized by FT-IR. The results show that the performance of mercury removal is related to the surface chemistry of activated coke,and the oxygen-containing functional groups are the important factor affecting the adsorption and catalysis of Hg⁰. The adsorption performance of Hg⁰ with activated coke is influenced by SO₂ obviously and inhibition is observed in the removal process. With increasing concentration of SO₂, from 400, 855 to 1 520 mL/m³, the concentration of Hg⁰ at the outlet of the reactor increased from 36, 43 to 48 μg/m³. The complex impact of NO on the adsorptive capacity of Hg⁰ is found that NO with lower concentration promotes the adsorption of elemental mercury while inhibits it at higher value in CO₂/N₂/O₂/NO/Hg⁰ system. The increasing concentration of NO with the stationary concentration of SO₂ has a promotion to mercury adsorption while O₂, NO, SO₂ and Hg⁰ exists simultaneously. However, the increasing concentration of SO₂ could enhance the mercury adsorption at initial stage and prevents it at the latter stage.