Elemental mercury （Hg^0） in flue gases can be efficiently captured by mercury chloride （HgCl2） solution. However, the absorption behaviors and the influencing effects are still poorly understood. The mechanism of ...Elemental mercury （Hg^0） in flue gases can be efficiently captured by mercury chloride （HgCl2） solution. However, the absorption behaviors and the influencing effects are still poorly understood. The mechanism of Hg^0 absorption by HgCl2 and the factors that control the removal were studied in this paper. It was found that when the mole ratio of Cl^- to HgCl2 is 10：1, the Hg^0 removal efficiency is the highest. Among the main mercury chloride species, HgCl3^- is the most efficient ion for Hg^0 removal in the HgCl2 absorption system when moderate concentrations of chloride ions exist. The Hg^0 absorption reactions in the aqueous phase were investigated computationaIIy using Moller-Plesset perturbation theory. The calculated Gibbs free energies and energy barriers are in excellent agreement with the results obtained from experiments. In the presence of SO3^2- and SO2, Hg^2＋ reduction occurred and Hg^0 removal efficiency decreased. The reduced Hg^0 removal can be controlled through increased chloride concentration to some degree. Low pH value in HgCla solution enhanced the Hg^0 removal efficiency, and the effect was more significant in dilute HgCl2 solutions. The presence of SO4^2- and NO3^- did not affect Hg^0 removal by HgCl2.展开更多
lronmaking using an oxygen blast furnace is an attractive approach for reducing energy consumption in the iron and steel industry. This paper presents a numerical study of gas-solid flow in an oxygen blast fur- nace b...lronmaking using an oxygen blast furnace is an attractive approach for reducing energy consumption in the iron and steel industry. This paper presents a numerical study of gas-solid flow in an oxygen blast fur- nace by coupling the discrete element method with computational fluid dynamics. The model reliability was verified by previous experimental results. The influences of particle diameter, shaft tuyere size, and specific ratio （X） of shaft-injected gas （51G） flowrate to total gas flowrate on the SIC penetration behavior and pressure field in the furnace were investigated. The results showed that gas penetration capacity in the furnace gradually decreased as the particle diameter decreased from 100 to 40 mm. Decreasing particle diameter and increasing shaft tuyere size both slightly increased the SIG concentration near the furnace wall but decreased it at the furnace center. The value of X has a significant impact on the SIG distribution. According to the pressure fields obtained under different conditions, the key factor affecting SIG penetration depth is the pressure difference between the upper and lower levels of the shaft tuyere. If the pressure difference is small, the SIG can easily penetrate to the furnace center.展开更多
In general, heavy elements contribute only to the superconductivity of hydrides. However, it acoustic phonon modes, which are less important for was revealed that the heavier elements could enhance the phonon-mediated...In general, heavy elements contribute only to the superconductivity of hydrides. However, it acoustic phonon modes, which are less important for was revealed that the heavier elements could enhance the phonon-mediated superconductivity in ternary hydrides. In the H3S-Xe system, a novel H3SXe compound was discovered by first-principle calculations. The structural phase transitions of H3SXe under high pressures were studied. The R-3m phase of H3SXe was predicted to appear at pressures above 80 GPa, which transitions to C2/m, P-3m1, and Pm-3m phases at pressures of 90, 160, and 220 GPa, respectively. It has been anticipated that the Pm-3m-H3SXe phase with a similar structural feature as that of Im-3m-H3S is a potential high-temperature superconductor with a Tc of 89 K at 240 GPa. The Tc value of H3SXe is lower than that of H3S at high pressure. The ＂H3S＂ host lattice of Pm- 3m-H3SXe is a crucial factor influencing the Tc value. The Xe atoms could accelerate the hydrogen-bond symmetrization. With the increase of the atomic number, the Tc value linearly increases in the H3S- noble-gas-element system. This indicates that the superconductivity can be modulated by changing the relative atomic mass of the noble-gas element.展开更多
基金supported by the Major State Basic Research Development Program (No. 2013CB430005)the National Natural Science Foundation of China (No. 51278294)the National High Technology Research and Development Program (No. 2012AA062504)
文摘Elemental mercury （Hg^0） in flue gases can be efficiently captured by mercury chloride （HgCl2） solution. However, the absorption behaviors and the influencing effects are still poorly understood. The mechanism of Hg^0 absorption by HgCl2 and the factors that control the removal were studied in this paper. It was found that when the mole ratio of Cl^- to HgCl2 is 10：1, the Hg^0 removal efficiency is the highest. Among the main mercury chloride species, HgCl3^- is the most efficient ion for Hg^0 removal in the HgCl2 absorption system when moderate concentrations of chloride ions exist. The Hg^0 absorption reactions in the aqueous phase were investigated computationaIIy using Moller-Plesset perturbation theory. The calculated Gibbs free energies and energy barriers are in excellent agreement with the results obtained from experiments. In the presence of SO3^2- and SO2, Hg^2＋ reduction occurred and Hg^0 removal efficiency decreased. The reduced Hg^0 removal can be controlled through increased chloride concentration to some degree. Low pH value in HgCla solution enhanced the Hg^0 removal efficiency, and the effect was more significant in dilute HgCl2 solutions. The presence of SO4^2- and NO3^- did not affect Hg^0 removal by HgCl2.
基金We gratefully acknowledge the support of the National Basic Research Program of China （973 Program） （No. 2012CB720401 ） and the Key Project of National Natural Science Foundation of China （No. 51134008）.
文摘lronmaking using an oxygen blast furnace is an attractive approach for reducing energy consumption in the iron and steel industry. This paper presents a numerical study of gas-solid flow in an oxygen blast fur- nace by coupling the discrete element method with computational fluid dynamics. The model reliability was verified by previous experimental results. The influences of particle diameter, shaft tuyere size, and specific ratio （X） of shaft-injected gas （51G） flowrate to total gas flowrate on the SIC penetration behavior and pressure field in the furnace were investigated. The results showed that gas penetration capacity in the furnace gradually decreased as the particle diameter decreased from 100 to 40 mm. Decreasing particle diameter and increasing shaft tuyere size both slightly increased the SIG concentration near the furnace wall but decreased it at the furnace center. The value of X has a significant impact on the SIG distribution. According to the pressure fields obtained under different conditions, the key factor affecting SIG penetration depth is the pressure difference between the upper and lower levels of the shaft tuyere. If the pressure difference is small, the SIG can easily penetrate to the furnace center.
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 11404134, 91745203, 51572108, 11634004, 11574109, and 11674122）, Programfor Changjiang Scholars and Innovative Research Team in Uni- versity （No. IRT 15R23）, National Fund for Fostering Talents of Basic Science （No.J1103202）, .lilin Provincial Science and Tech- nology Development Project of China （Grant Nos. 20160520016JH and 20170520116JH） and China Postdoctoral Science Foundation （Grant Nos. 2014M561279 and 2016T90246）. Parts of calcula- tions were performed in the High Performance Computing Center （HPCC） of Jilin University.
文摘In general, heavy elements contribute only to the superconductivity of hydrides. However, it acoustic phonon modes, which are less important for was revealed that the heavier elements could enhance the phonon-mediated superconductivity in ternary hydrides. In the H3S-Xe system, a novel H3SXe compound was discovered by first-principle calculations. The structural phase transitions of H3SXe under high pressures were studied. The R-3m phase of H3SXe was predicted to appear at pressures above 80 GPa, which transitions to C2/m, P-3m1, and Pm-3m phases at pressures of 90, 160, and 220 GPa, respectively. It has been anticipated that the Pm-3m-H3SXe phase with a similar structural feature as that of Im-3m-H3S is a potential high-temperature superconductor with a Tc of 89 K at 240 GPa. The Tc value of H3SXe is lower than that of H3S at high pressure. The ＂H3S＂ host lattice of Pm- 3m-H3SXe is a crucial factor influencing the Tc value. The Xe atoms could accelerate the hydrogen-bond symmetrization. With the increase of the atomic number, the Tc value linearly increases in the H3S- noble-gas-element system. This indicates that the superconductivity can be modulated by changing the relative atomic mass of the noble-gas element.
