Effects of Coal-Fired Flue Gas Components on Mercury Removal by the Mechanochemical S-Modified Petroleum Coke

Abstract

In this work, the effects of coal-fired flue gas components (O 2 , CO 2 , SO 2 , and NO) on the Hg 0 removal by the promising mercury removal adsorbent mechanochemical S-modified petroleum coke were characterized and analyzed in terms of the Hg 0 removal efficiency, mercury adsorption capacity, and mercury mass balance. The results show that the mechanochemical S-modified petroleum coke with a theoretical sulfur content of 21% (named TSC-21) is the best candidate for mercury removal based on the Hg 0 removal efficiency, Hg 0 removal capacity, and difference ratio of Hg 0 removal capacity (anti-interference ability) in the basic and full-component simulated flue gas atmosphere (N 2 + O 2 + CO 2 , N 2 + O 2 + CO 2 + SO 2 + NO). The maximum value (MV) and stable value (SV) of the Hg 0 removal efficiency of TSC-21 in the basic simulated flue gas atmosphere are 99.25% (MV) and 91.17% (SV), respectively. O 2 , CO 2 , and NO all promote the Hg 0 removal by the adsorbent, but they benefit the Hg 0 oxidation while inhibiting the Hg 0 adsorption. The promoting effect of O 2 on the Hg 0 removal by TSC-21 is affected by the reaction time, which is especially obvious after 1 min. The presence of SO 2 inhibits the oxidation and adsorption of Hg 0 , which in turn reduces the Hg 0 removal performance of the adsorbent. The improving effects on the oxidative escape of Hg 0 by CO 2 is higher than that by NO and O 2 . TSC-21 acts more as an oxidant than an adsorbent for Hg 0 removal.