A novel ferruginous active absorbent, prepared by fly ash, industrial lime and the additive Fe（VI）, was introduced for synchronous abatement of binary mixtures of SO2–NOx from simulated coal-fired flue gas. The syn...A novel ferruginous active absorbent, prepared by fly ash, industrial lime and the additive Fe（VI）, was introduced for synchronous abatement of binary mixtures of SO2–NOx from simulated coal-fired flue gas. The synergistic action of various factors on the absorption of SO2 and NOx was investigated. The results show that a strong synergistic effect exists between Fe（VI） dose and reaction temperature for the desulfurization. It was observed that in the denitration process, the synergy of Fe（VI） dose and Ca/（S ＋ N） had the most significant impact on the removal of NO, followed by the synergy of Fe（VI） and reaction temperature, and then the synergy of reaction temperature and flue gas humidity. A scanning electron microscope（SEM） and an accessory X-ray energy spectrometer（EDS）were used to observe the surface characteristics of the raw and spent absorbent as well as fly ash. A reaction mechanism was proposed based on chemical analysis of sulfur and nitrogen species concentrations in the spent absorbent. The Gibbs free energy, equilibrium constants and partial pressures of the SO2–NOx binary system were determined by thermodynamics.展开更多
With an extended Langmuir isotherm, a Riemann problem for one-dimensional binary gas enhanced coalbed methane (ECBM) process is investigated. A new analytical solution to the Riemann problem, based on the method of ch...With an extended Langmuir isotherm, a Riemann problem for one-dimensional binary gas enhanced coalbed methane (ECBM) process is investigated. A new analytical solution to the Riemann problem, based on the method of characteristics, is developed by introducing a gas selectivity ratio representing the gas relative sorption affinity. The influence of gas selectivity ratio on the enhanced coalbed methane processes is identified.展开更多
An implicit discrete unified gas kinetic scheme(DUGKS)is developed for multiscale steady flows of binary gas mixtures by solving the Andries-Aoki-Perthame kinetic model(AAP).To ensure the high convergence efficiency f...An implicit discrete unified gas kinetic scheme(DUGKS)is developed for multiscale steady flows of binary gas mixtures by solving the Andries-Aoki-Perthame kinetic model(AAP).To ensure the high convergence efficiency for all flow regimes,the microscopic and macroscopic asynchronous iterative strategies are used,where both the macroscopic and microscopic equations are solved iteratively by the LowerUpper Symmetric Gauss-Seidel(LU-SGS)method.The macroscopic iteration is conducted to solve the macroscopic governing equations containing source terms as an implicit prediction step to evaluate the local equilibrium state of the microscopic evolution,and the macroscopic flux used in the macroscopic iteration is obtained by taking moments of the distribution function.Besides,to keep the asymptotic preserving properties,the numerical flux across the cell interface is reconstructed by the characteristic solution of the kinetic governing equations for both species like the explicit DUGKS for a single gas.Several numerical tests,including the Couette flow,the lid-driven cavity flow,and the flows through a slit of different mixtures,are simulated to verify the accuracy and efficiency of the present scheme for binary mixtures.Furthermore,compared to the explicit DUGKS,the implicit scheme improves the computational efficiency by 1-2 orders of magnitude.展开更多
Highly selective separation of CO_2 from its methane-containing binary gas mixture can be achieved by using Poly(ether-block-amide)(PEBAX)mixed matrix membranes(MMMs).According to FESEM and AFM analyses,silica-based n...Highly selective separation of CO_2 from its methane-containing binary gas mixture can be achieved by using Poly(ether-block-amide)(PEBAX)mixed matrix membranes(MMMs).According to FESEM and AFM analyses,silica-based nanoparticles were homogenously integrated within the polymer matrix,facilitating penetration of CO_2 through the membrane while acting as barrier for methane gas.The membrane containing 4.6 wt% fumed silica(FS)(PEBAX/4.6 wt%FS)exhibits astonishing selectivity results where binary gas mixture of CO_2/CH_4 was used as feed gas.As detected by gas chromatography,in the permeate side,data showed a significant increase of CO_2 permeance,while CH_4 transport through the mixed matrix membrane was not detectable.Moreover,PEBAX/4.6 wt%FS greatly exceeds the Robeson limit.According to data reported on CO_2/CH_4 gas pair separation in the literature,the results achieved in this work are beyond those data reported in the literature,particularly when PEBAX/4.6 wt%FS membrane was utilized.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 51308212, 10974053)the National Key Technology R&D Program (No. 2011BAI02B03)+1 种基金the Fundamental Research Funds for the Central Universities (No. 13ZD18)the State Scholarship Fund (No. 201206735009)
文摘A novel ferruginous active absorbent, prepared by fly ash, industrial lime and the additive Fe（VI）, was introduced for synchronous abatement of binary mixtures of SO2–NOx from simulated coal-fired flue gas. The synergistic action of various factors on the absorption of SO2 and NOx was investigated. The results show that a strong synergistic effect exists between Fe（VI） dose and reaction temperature for the desulfurization. It was observed that in the denitration process, the synergy of Fe（VI） dose and Ca/（S ＋ N） had the most significant impact on the removal of NO, followed by the synergy of Fe（VI） and reaction temperature, and then the synergy of reaction temperature and flue gas humidity. A scanning electron microscope（SEM） and an accessory X-ray energy spectrometer（EDS）were used to observe the surface characteristics of the raw and spent absorbent as well as fly ash. A reaction mechanism was proposed based on chemical analysis of sulfur and nitrogen species concentrations in the spent absorbent. The Gibbs free energy, equilibrium constants and partial pressures of the SO2–NOx binary system were determined by thermodynamics.
文摘With an extended Langmuir isotherm, a Riemann problem for one-dimensional binary gas enhanced coalbed methane (ECBM) process is investigated. A new analytical solution to the Riemann problem, based on the method of characteristics, is developed by introducing a gas selectivity ratio representing the gas relative sorption affinity. The influence of gas selectivity ratio on the enhanced coalbed methane processes is identified.
基金supported by the National Natural Science Foundation of China(Grants No.12002131 and No.11872024)Project funded by China Postdoctoral Science Foundation(No.2020M672347 and No.2021M701565).
文摘An implicit discrete unified gas kinetic scheme(DUGKS)is developed for multiscale steady flows of binary gas mixtures by solving the Andries-Aoki-Perthame kinetic model(AAP).To ensure the high convergence efficiency for all flow regimes,the microscopic and macroscopic asynchronous iterative strategies are used,where both the macroscopic and microscopic equations are solved iteratively by the LowerUpper Symmetric Gauss-Seidel(LU-SGS)method.The macroscopic iteration is conducted to solve the macroscopic governing equations containing source terms as an implicit prediction step to evaluate the local equilibrium state of the microscopic evolution,and the macroscopic flux used in the macroscopic iteration is obtained by taking moments of the distribution function.Besides,to keep the asymptotic preserving properties,the numerical flux across the cell interface is reconstructed by the characteristic solution of the kinetic governing equations for both species like the explicit DUGKS for a single gas.Several numerical tests,including the Couette flow,the lid-driven cavity flow,and the flows through a slit of different mixtures,are simulated to verify the accuracy and efficiency of the present scheme for binary mixtures.Furthermore,compared to the explicit DUGKS,the implicit scheme improves the computational efficiency by 1-2 orders of magnitude.
基金financial support of Research Institute of Petroleum Industry
文摘Highly selective separation of CO_2 from its methane-containing binary gas mixture can be achieved by using Poly(ether-block-amide)(PEBAX)mixed matrix membranes(MMMs).According to FESEM and AFM analyses,silica-based nanoparticles were homogenously integrated within the polymer matrix,facilitating penetration of CO_2 through the membrane while acting as barrier for methane gas.The membrane containing 4.6 wt% fumed silica(FS)(PEBAX/4.6 wt%FS)exhibits astonishing selectivity results where binary gas mixture of CO_2/CH_4 was used as feed gas.As detected by gas chromatography,in the permeate side,data showed a significant increase of CO_2 permeance,while CH_4 transport through the mixed matrix membrane was not detectable.Moreover,PEBAX/4.6 wt%FS greatly exceeds the Robeson limit.According to data reported on CO_2/CH_4 gas pair separation in the literature,the results achieved in this work are beyond those data reported in the literature,particularly when PEBAX/4.6 wt%FS membrane was utilized.
