Experimental study on mercury removal from coal-fired flue gas by sulfur modified biomass coke with mechanochemical method

Zhao, Shilin; Luo, Hui; Ma, Anjun; Sun, Zhiqiang; Zheng, Rong

doi:10.1016/j.fuel.2021.122201

Cited by 27 publications

(10 citation statements)

References 47 publications

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“…This variation indicates that thiophene (i.e., -C-S x -C-, x = 1-2), sulfoxide, and C-S were beneficial to improving the Hg 0 removal capacity. This is in line with a previous study [59], i.e., findings that the sulfur in sulfide existing in a low state as well as the reducing sulfur (such as thiosulfone) had a high affinity with the Hg 0 atom. Electrons around the sulfur atom were easy to combine with Hg 0 , which was conducive to the removal of mercury.…”

Section: Reaction Mechanismsupporting

confidence: 93%

A Molten-Salt Pyrolysis Synthesis Strategy toward Sulfur-Functionalized Carbon for Elemental Mercury Removal from Coal-Combustion Flue Gas

Yang

Meng

et al. 2022

Energies

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The emission of mercury from coal combustion has caused consequential hazards to the ecosystem. The key challenge to abating the mercury emission is to explore highly efficient adsorbents. Herein, sulfur-functionalized carbon (S-C) was synthesized by using a molten-salt pyrolysis strategy and employed for the removal of elemental mercury from coal-combustion flue gas. An ideal pore structure, which was favorable for the internal diffusion of the Hg0 molecule in carbon, was obtained by using a SiO2 hard template and adjusting the HF etching time. The as-prepared S-C with an HF etching time of 10 h possessed a saturation Hg0 adsorption capacity of 89.90 mg·g−1, far exceeding that of the commercial sulfur-loaded activated carbons (S/C). The S-C can be applied at a wide temperature range of 25–125 °C, far exceeding that of commercial S/C. The influence of flue gas components, such as SO2, NO, and H2O, on the Hg0 adsorption performance of S-C was insignificant, indicating a good applicability in real-world applications. The mechanism of the Hg0 removal by S-C was proposed, i.e., the reduced components, including sulfur thiophene, sulfoxide, and C-S, displayed a high affinity toward Hg0, which could guarantee the stable immobilization of Hg0 as HgS in the adsorbent. Thus, the molten-salt pyrolysis strategy has a broad prospect in the application of one-pot carbonization and functionalization sulfur-containing organic precursors as efficient adsorbents for Hg0.

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Section: Reaction Mechanismsupporting

confidence: 93%

A Molten-Salt Pyrolysis Synthesis Strategy toward Sulfur-Functionalized Carbon for Elemental Mercury Removal from Coal-Combustion Flue Gas

Yang

Meng

et al. 2022

Energies

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“…2,3 Hg 2+ and Hg P can be removed by power plant pollution control devices, 4,5 while Hg 0 is considered the key component to be removed as a result of its volatility and low solubility in water. 6,7 Activated carbon injection technology is currently widely used for mercury removal. Biomass is considered an ideal substitute for activated carbon.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Mercury Removal Behavior by Modified Biomass Coke in Oxy-fuel Combustion Flue Gas

An,

Le,

Zhong

et al. 2024

Energy Fuels

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The presence of circulating flue gas in oxy-fuel combustion leads to mercury pollution. Acid−chlorine-modified biomass coke was used to prepare mercury adsorbents. The influence of individual flue gas components (HCl, NO, SO 2 , and H 2 O) and complex flue gas on the behavior of modified straw coke for mercury removal under an oxy-fuel combustion atmosphere was studied. The mechanism of the flue gas reaction with mercury was investigated using temperature-programmed desorption (TPD) characterization. The density functional theory (DFT) was employed to study the mechanism of mercury removal by the adsorbent. The results showed that H 2 O has a dual effect on mercury removal: the low concentrations of H 2 O promote mercury removal, while moderate to high concentrations of H 2 O inhibit it. HCl and NO exhibited promotional effects on mercury removal. SO 2 competed with Hg 0 for active adsorption sites or adsorbed on the surface of the adsorbent, consuming active oxygen species and chlorinated functional groups to inhibit the adsorption and oxidation of Hg 0 . Under the atmosphere of complex flue gas, H 2 O and SO 2 inhibited the generation of highly oxidizing intermediate products from HCl and NO. Additionally, the coexistence of H 2 O and SO 2 generated H 2 SO 4 , further blocking the surface pore structure and hindering the diffusion of Hg 0 on the adsorbent surface. The result of the electron localization function (ELF) indicated that the introduction of O and Cl atoms can form stable covalent compounds (C�O and C−Cl) through bonding with the carbonaceous surface, serving as favorable chemical adsorption sites. The high reactivity of Cl induces Hg 0 adsorption, and the presence of O atoms not only acts as a chemical adsorption site but also activates the reactivity of Cl atoms, promoting the efficiency of mercury removal. This study provided a theoretical basis for the application of mercury adsorbents in oxy-fuel combustion fuel gas.

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“…Biochar has an ideal large specific surface area, rich pore structure, strong thermal stability, and great potential to replace industrial activated carbon. − Sulfur-containing substances are usually used for the modification of adsorbents because sulfur can provide a pair of lone electrons to form a covalent bond with mercury during the reaction process, and sulfur shows a strong affinity for mercury . Zhao et al used wood chips as biomass raw materials and selected sulfur-containing substances as modifiers. They conducted mercury removal experiments and found that the best mercury removal efficiency was above 96%.…”

Section: Introductionmentioning

confidence: 99%

Elemental Mercury Removal from Coal-Fired Flue Gas on Sulfur-Modified Activated Biomass Coke: Experiment and Simulation

Zeng

Wang

Kang

et al. 2023

Ind. Eng. Chem. Res.

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It is necessary to find a better method to remove mercury from coal-fired flue gas. This work proposes the use of corn stalk coke to remove mercury from coal-fired flue gas and through elemental sulfur (CSC-S), water vapor activation (CSC-H 2 O), and sulfur modification combined with water vapor activation (CSC-H 2 O-S) to prepare three different adsorbents. The mercury removal performance of the adsorbents prepared by different methods was evaluated on a small fixed-bed mercury removal experimental platform. The experimental results showed that the order of mercury removal efficiency of the four adsorbents was: CSC-H 2 O-S > CSC-S > CSC-H 2 O > CSC. Brunauer−Emmett−Teller (BET), Fourier transform infrared (FTIR) spectroscopy, and Xray photoelectron spectroscopy (XPS) were adopted to study the physical and chemical properties of the adsorbent surface and the mechanism of mercury removal. The results showed that water vapor activation can improve the pore structure of the adsorbent, increase its specific surface area, and generate new oxygen-containing functional groups on the surface of the adsorbent. The adsorption kinetic model further demonstrated that the water vapor activation process can improve the physical adsorption performance of corn stalk char, and the sulfur modification process can improve the chemical adsorption performance of corn stalk char. Quantum chemical studies have shown that the surface structure doped with S and O atoms is conducive to enhancing the adsorption of Hg 0 .

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Experimental study on mercury removal from coal-fired flue gas by sulfur modified biomass coke with mechanochemical method

Cited by 27 publications

References 47 publications

A Molten-Salt Pyrolysis Synthesis Strategy toward Sulfur-Functionalized Carbon for Elemental Mercury Removal from Coal-Combustion Flue Gas

A Molten-Salt Pyrolysis Synthesis Strategy toward Sulfur-Functionalized Carbon for Elemental Mercury Removal from Coal-Combustion Flue Gas

Investigation of Mercury Removal Behavior by Modified Biomass Coke in Oxy-fuel Combustion Flue Gas

Elemental Mercury Removal from Coal-Fired Flue Gas on Sulfur-Modified Activated Biomass Coke: Experiment and Simulation

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