Higher concentrations of Hg can be emitted from coal pyrolysis or gasification than from coal combustion, especially elemental Hg. Highly efficient Hg removal technology from coal-derived fuel gas is thus of great imp...Higher concentrations of Hg can be emitted from coal pyrolysis or gasification than from coal combustion, especially elemental Hg. Highly efficient Hg removal technology from coal-derived fuel gas is thus of great importance. Based on the very excellent Hg removal ability of Pd and the high adsorption abilities of activated carbon（AC） for H2 S and Hg, a series of Pd/AC sorbents was prepared by using pore volume impregnation, and their performance in capturing Hg and H2 S from coal-derived fuel gas was investigated using a laboratory-scale fixed-bed reactor. The effects of loading amount, reaction temperature and reaction atmosphere on Hg removal from coal-derived fuel gas were studied. The sorbents were characterized by N2 adsorption, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS）. The results indicated that the efficiency of Hg removal increased with the increasing of Pd loading amount, but the effective utilization rate of the active component Pd decreased significantly at the same time. High temperature had a negative influence on the Hg removal. The efficiency of Hg removal in the N2-H2S-H2-CO-Hg atmosphere（simulated coal gas） was higher than that in N2-H2S-Hg and N2-Hg atmospheres, which showed that H2 and CO, with their reducing capacity, could benefit promote the removal of Hg. The XPS results suggested that there were two different ways of capturing Hg over sorbents in N2-H2S-Hg and N2-Hg atmospheres.展开更多
An activated carbon （AC） supported Pd catalyst was used to develop a highly efficient in situ adsorption-catalysis system for the removal of low concentrations of o-xylene. In this study, three kinds of Pd/AC cataly...An activated carbon （AC） supported Pd catalyst was used to develop a highly efficient in situ adsorption-catalysis system for the removal of low concentrations of o-xylene. In this study, three kinds of Pd/AC catalysts were prepared and tested to investigate the synergistic efficiency between adsorption and catalysis for o-xylene removal. The Pd/AC catalyst was first used as an adsorbent to concentrate dilute o-xylene at low temperature. After saturated adsorption, the adsorbed o-xylene was oxidized to CO2 and H20 by raising the temperature of the catalyst bed. The results showed that more than 99% of the adsorbed o-xylene was completely oxidized to CO2 over a 5% Pd/AC catalyst at 140℃. Brunauer-Emmett-Teller （BET） analysis, scanning electron microscopy （SEM）, temperatureprogrammed desorption （TPD）, and temperature-programmed oxidation （TPO） were applied to investigate the physical properties of o-xylene adsorption-desorption and the in situ adsorption-catalysis activity of the AC support and Pd/AC catalyst. A synergistic relationship between the AC support and the active Pd species for the removal of low concentrations of o-xylene was established.展开更多
对Pd/AC催化剂上对苯二甲酸(TA)加氢精制过程中的对羧基苯甲醛(4-CBA)加氢反应进行了研究。考察了氢分压、反应温度、催化剂颗粒大小对4-CBA消逝速率的影响,结果表明:在高于0.35 M Pa时,氢分压对4-CBA加氢反应速率的影响很小,而温度和...对Pd/AC催化剂上对苯二甲酸(TA)加氢精制过程中的对羧基苯甲醛(4-CBA)加氢反应进行了研究。考察了氢分压、反应温度、催化剂颗粒大小对4-CBA消逝速率的影响,结果表明:在高于0.35 M Pa时,氢分压对4-CBA加氢反应速率的影响很小,而温度和催化剂粒度大小对加氢反应的影响显著。同时,工业条件下的TA加氢精制过程存在着严重的内外扩散。采用幂函数动力学模型方程利用M atlab拟合得到了不同粒度催化剂上的表观动力学方程。展开更多
Phenol hydrogenation is a green route to prepare cyclohexanone,an intermediate for the production of nylon 66 and nylon 6.The development of high-performance catalysts still keeps a great challenge.Herein,the activate...Phenol hydrogenation is a green route to prepare cyclohexanone,an intermediate for the production of nylon 66 and nylon 6.The development of high-performance catalysts still keeps a great challenge.Herein,the activated carbon(AC)was modified with an acidic material Nb_(2)O_(5)to adjust the microstructure and surface properties of AC,and the influences of the calcination temperature and Nb_(2)O_(5)content on the catalytic performance of the Pd/AC-Nb_(2)O_(5)catalysts for the phenol hydrogenation to cyclohexanone were investigated.The Nb_(2)O_(5)with proper content can be highly uniformly distributed on the AC surface,enhancing the acidity of the Pd/AC-Nb_(2)O_(5)catalysts with comparable specific surface area and Pd dispersion,thereby improving the catalytic activity.The hybrid Pd/AC-10 Nb_(2)O_(5)-500 catalyst exhibits the synergistic effect between the Pd nanoparticles and AC-10 Nb_(2)O_(5),which enhances the catalytic activity for the hydrogenation of phenol.Furthermore,the as-prepared Pd/AC-10 Nb_(2)O_(5)-500 catalyst shows good reusability during 7 reaction cycles.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 21006067, 21276170)the Shanxi Province Natural Science Foundation (Nos. 2010021008-1, 201101008-4)the National High-Tech Research and Development Program (863) of China (No. 2013AA065404E)
文摘Higher concentrations of Hg can be emitted from coal pyrolysis or gasification than from coal combustion, especially elemental Hg. Highly efficient Hg removal technology from coal-derived fuel gas is thus of great importance. Based on the very excellent Hg removal ability of Pd and the high adsorption abilities of activated carbon（AC） for H2 S and Hg, a series of Pd/AC sorbents was prepared by using pore volume impregnation, and their performance in capturing Hg and H2 S from coal-derived fuel gas was investigated using a laboratory-scale fixed-bed reactor. The effects of loading amount, reaction temperature and reaction atmosphere on Hg removal from coal-derived fuel gas were studied. The sorbents were characterized by N2 adsorption, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS）. The results indicated that the efficiency of Hg removal increased with the increasing of Pd loading amount, but the effective utilization rate of the active component Pd decreased significantly at the same time. High temperature had a negative influence on the Hg removal. The efficiency of Hg removal in the N2-H2S-H2-CO-Hg atmosphere（simulated coal gas） was higher than that in N2-H2S-Hg and N2-Hg atmospheres, which showed that H2 and CO, with their reducing capacity, could benefit promote the removal of Hg. The XPS results suggested that there were two different ways of capturing Hg over sorbents in N2-H2S-Hg and N2-Hg atmospheres.
基金supported by the National Natural Science Foundation of China (No. 20607029)the Ministry of Science and Technology of China (No. 2007AA061402)
文摘An activated carbon （AC） supported Pd catalyst was used to develop a highly efficient in situ adsorption-catalysis system for the removal of low concentrations of o-xylene. In this study, three kinds of Pd/AC catalysts were prepared and tested to investigate the synergistic efficiency between adsorption and catalysis for o-xylene removal. The Pd/AC catalyst was first used as an adsorbent to concentrate dilute o-xylene at low temperature. After saturated adsorption, the adsorbed o-xylene was oxidized to CO2 and H20 by raising the temperature of the catalyst bed. The results showed that more than 99% of the adsorbed o-xylene was completely oxidized to CO2 over a 5% Pd/AC catalyst at 140℃. Brunauer-Emmett-Teller （BET） analysis, scanning electron microscopy （SEM）, temperatureprogrammed desorption （TPD）, and temperature-programmed oxidation （TPO） were applied to investigate the physical properties of o-xylene adsorption-desorption and the in situ adsorption-catalysis activity of the AC support and Pd/AC catalyst. A synergistic relationship between the AC support and the active Pd species for the removal of low concentrations of o-xylene was established.
文摘对Pd/AC催化剂上对苯二甲酸(TA)加氢精制过程中的对羧基苯甲醛(4-CBA)加氢反应进行了研究。考察了氢分压、反应温度、催化剂颗粒大小对4-CBA消逝速率的影响,结果表明:在高于0.35 M Pa时,氢分压对4-CBA加氢反应速率的影响很小,而温度和催化剂粒度大小对加氢反应的影响显著。同时,工业条件下的TA加氢精制过程存在着严重的内外扩散。采用幂函数动力学模型方程利用M atlab拟合得到了不同粒度催化剂上的表观动力学方程。
基金The financial supports from the National Natural Science Foundation(21776127,21921006)the Jiangsu Province Key R&D Program(BE2018009-2)+3 种基金the Jiangsu Province natural science research of College and university general project(20KJB540003)a project funded by the priority academic program development of Jiangsu higher education institutions(PAPD)the State Key Laboratory of Materials-Oriented Chemical Engineering(ZK201902)the outstanding young teacher’s project of Changzhou Vocational Institute of Textile and Garment of China。
文摘Phenol hydrogenation is a green route to prepare cyclohexanone,an intermediate for the production of nylon 66 and nylon 6.The development of high-performance catalysts still keeps a great challenge.Herein,the activated carbon(AC)was modified with an acidic material Nb_(2)O_(5)to adjust the microstructure and surface properties of AC,and the influences of the calcination temperature and Nb_(2)O_(5)content on the catalytic performance of the Pd/AC-Nb_(2)O_(5)catalysts for the phenol hydrogenation to cyclohexanone were investigated.The Nb_(2)O_(5)with proper content can be highly uniformly distributed on the AC surface,enhancing the acidity of the Pd/AC-Nb_(2)O_(5)catalysts with comparable specific surface area and Pd dispersion,thereby improving the catalytic activity.The hybrid Pd/AC-10 Nb_(2)O_(5)-500 catalyst exhibits the synergistic effect between the Pd nanoparticles and AC-10 Nb_(2)O_(5),which enhances the catalytic activity for the hydrogenation of phenol.Furthermore,the as-prepared Pd/AC-10 Nb_(2)O_(5)-500 catalyst shows good reusability during 7 reaction cycles.
