Complete Reaction Mechanisms of Mercury Binding on Petroleum Coke and Brominated Petroleum Coke

Abstract

Recently, petroleum coke has been developed to remove elemental mercury (Hg 0 ) in flue gas as a carbon-based adsorbent. Brominated modified petroleum coke with a new bromine modification method showed promising results for capturing Hg 0 . Revealing the mechanism of mercury adsorption processes on petroleum coke and brominated modified petroleum coke is crucial to the designing and development of cheap and efficient adsorbents. To simulate the different edges of petroleum coke, six different cluster models were established and verified. The possible reaction paths of HgO, HgBr, and HgBr 2 formation on petroleum coke were presented, and the binding energies were given. The results revealed that HgO, HgBr, and HgBr 2 were bound on the surface of brominated modified petroleum coke and HgBr was most likely to be generated. The effects of S, N, O, and Br in the brominated modified petroleum coke on elemental mercury adsorption were also revealed, which could be a reference to mercury capture efficiency of brominated modified petroleum with different S, N, O, and Br contents.

The Effects of Physical-Chemical Evolution of High-Sulfur Petroleum Coke on Hg0 Removal from Coal-Fired Flue Gas and Exploration of Its Micro-Scale Mechanism

“…Therefore, the selections of appropriate functional, basis sets and calculation methods are crucial to keep the accuracy matching the experimental results and reduce the calculation loading [ 66 ]. There exist two assumptions of the adsorption process on the carbon-based surface including plane and spatial adsorption morphology [ 67 ]. Plane adsorption occurs when the Hg 0 atom is put near the unsaturated C, while spatial adsorption occurs there is a lack of or far from the unsaturated C. Furthermore, in the recent two years, some researchers not only proposed the Hg 0 removal mechanism of activated carbon-based adsorbent but also successfully explored the activation mechanism of raw materials, which promoted the whole process of activation of HSPC and Hg 0 removal.…”

“…Chen Chen et al [ 67 ] built six typical edges of HSPC including thiophene-containing, pyrrole-containing, C=O-containing, C–O–C-containing, pyridine-containing, and pure edges. The brominated process and the complete reaction mechanisms of mercury removal by simulation were presented.…”

“…The existence of active C led to the adsorption process mainly being the platform reaction rather than the spatial reaction pathway. The Cl atom could strongly bind with C as chemical adsorption like Br [ 67 ]. Chompoonut et al [ 73 ] selected a two-row graphene model to reveal the strong effect of halide type on the activation energy barrier of HgX formation, which was in the order of HgI < HgBr < HgCl.…”

“…[ 69 ]. 2015, Energy and Fuels and ( b ) selected edge model of brominated HSPC [ 67 ]. Reprinted/adapted with permission from Ref.…”

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

“…Xiao et al , brominated petroleum coke using mechanochemical methods and found that the mercury removal efficiency of raw petroleum coke (RPC) was greatly improved with the highest value of above 99%. Chen et al used the density functional theory to analyze the mercury removal mechanism by brominated petroleum coke. It found that bromine on the petroleum coke surface enabled HgO and HgBr to be generated easily due to the increase of their adsorption energy and the decrease of their activation energy.…”