The removal of H_(2)S from coke oven gas (COG) is an important issue for the further utilization of COG. Zeolites could be used for industrial desulfurization owing to their high thermal stability and regenerability. ...The removal of H_(2)S from coke oven gas (COG) is an important issue for the further utilization of COG. Zeolites could be used for industrial desulfurization owing to their high thermal stability and regenerability. However, further analysis on the kinetics of deep desulfurization using zeolites is necessary to provide relevant information for industrial design. In this study, the desulfurization breakthrough curves of faujasite (FAU) zeolite in COG were measured using a fixed bed reactor. The adsorption isotherm was investigated using the Langmuir, Freundlich, Temkin, Dubinin-Radushkevich models. The adsorption saturated capacity of H_(2)S was inversely related to the temperature. The results show that the Langmuir model best fits the adsorption isotherm with a lower value of root-mean-square-error (RMSE) and Chi-Square (χ^(2)), and the calculated activation energy is 14.62 kJ·mol^(−1). The adsorption kinetics were investigated using pseudo-first-order (PFO), pseudo-second-order (PSO), Bangham and Weber-Morris models. The Bangham model fitted the kinetic data well, indicating that pore diffusion is an influential factor in the adsorption process. The Weber-Morris model suggests that the adsorption rate was not solely determined by the pore diffusion, but was also influenced by the active site on the FAU zeolite. The adsorption breakthrough curves under different gas flow rates were fitted using the bed depth service time (BDST) model, and it provides an accurate prediction of the breakthrough time with a small relative error. The results of thermodynamic analysis demonstrated the feasibility and spontaneity (ΔG<0) and exothermic (ΔH<0) nature of the adsorption process of the FAU zeolite for H_(2)S under COG.展开更多
The interaction between the adsorbed methylamine(MA) and siliceous FAU zeolite with a perfect framework is investigated with XRD, 29 Si and 13 C MAS NMR and FTIR. As methylamine is loaded into the zeolite, the crystal...The interaction between the adsorbed methylamine(MA) and siliceous FAU zeolite with a perfect framework is investigated with XRD, 29 Si and 13 C MAS NMR and FTIR. As methylamine is loaded into the zeolite, the crystal structure of the zeolite changes. One peak splits to four peaks for the 29 Si MAS NMR spectrum, and the IR vibration of framework with a high resolution become simpler. The fact indicates that there is a strong interaction between adsorbed methylamine and Si—O framework of FAU zeolite, leading to high A T value of affinity index for methylamine on the zeolite. The order structure of MA/FAU associate is discussed as well.展开更多
对有模板剂和无模板剂条件下纳米 A 型和 FAU 型沸石的合成方法及生长机理进行了综述。当合成液中无模板剂存在时,所得产物中仅部分颗粒粒径小于100 nm,且粒径分布较宽;当在合成液中添加模板剂时,合成出的纳米沸石粒径均一且容易控制。...对有模板剂和无模板剂条件下纳米 A 型和 FAU 型沸石的合成方法及生长机理进行了综述。当合成液中无模板剂存在时,所得产物中仅部分颗粒粒径小于100 nm,且粒径分布较宽;当在合成液中添加模板剂时,合成出的纳米沸石粒径均一且容易控制。纳米 A 型和 FAU 型沸石合成机理的研究表明,无模板剂时,纳米 A 型沸石由无定形凝胶颗粒的随机聚集体晶化形成,纳米FAU 型沸石由大量小晶体随机聚集形成;有模板剂存在时,纳米 A 型与 FAU 型沸石均由分散的无定形凝胶颗粒晶化形成。开发在无需添加模板剂或尽量少用模板剂的条件下制备粒径小且分布窄的纳米沸石的新方法是今后的研究方向。展开更多
采用核磁、红外、XRD研究了FAU硅沸石与吸附的乙胺之间的相互作用,XRD谱显示乙胺的吸入导致沸石晶胞收缩、对称性改变,立方变四方.^(29)Si MAS NMR上,FAU硅沸石的单峰分裂成四重峰,同时骨架的红外吸收峰移向低频.这些结果表明,FAU骨架...采用核磁、红外、XRD研究了FAU硅沸石与吸附的乙胺之间的相互作用,XRD谱显示乙胺的吸入导致沸石晶胞收缩、对称性改变,立方变四方.^(29)Si MAS NMR上,FAU硅沸石的单峰分裂成四重峰,同时骨架的红外吸收峰移向低频.这些结果表明,FAU骨架与吸附的乙胺之间存在着强烈的相互作用.展开更多
基金support of Ningbo Fareast Tech Catalyst Engineering Co.,Ltd,the National Natural Science Foundation of China(22478275)Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(2022SX-TD014).
文摘The removal of H_(2)S from coke oven gas (COG) is an important issue for the further utilization of COG. Zeolites could be used for industrial desulfurization owing to their high thermal stability and regenerability. However, further analysis on the kinetics of deep desulfurization using zeolites is necessary to provide relevant information for industrial design. In this study, the desulfurization breakthrough curves of faujasite (FAU) zeolite in COG were measured using a fixed bed reactor. The adsorption isotherm was investigated using the Langmuir, Freundlich, Temkin, Dubinin-Radushkevich models. The adsorption saturated capacity of H_(2)S was inversely related to the temperature. The results show that the Langmuir model best fits the adsorption isotherm with a lower value of root-mean-square-error (RMSE) and Chi-Square (χ^(2)), and the calculated activation energy is 14.62 kJ·mol^(−1). The adsorption kinetics were investigated using pseudo-first-order (PFO), pseudo-second-order (PSO), Bangham and Weber-Morris models. The Bangham model fitted the kinetic data well, indicating that pore diffusion is an influential factor in the adsorption process. The Weber-Morris model suggests that the adsorption rate was not solely determined by the pore diffusion, but was also influenced by the active site on the FAU zeolite. The adsorption breakthrough curves under different gas flow rates were fitted using the bed depth service time (BDST) model, and it provides an accurate prediction of the breakthrough time with a small relative error. The results of thermodynamic analysis demonstrated the feasibility and spontaneity (ΔG<0) and exothermic (ΔH<0) nature of the adsorption process of the FAU zeolite for H_(2)S under COG.
文摘The interaction between the adsorbed methylamine(MA) and siliceous FAU zeolite with a perfect framework is investigated with XRD, 29 Si and 13 C MAS NMR and FTIR. As methylamine is loaded into the zeolite, the crystal structure of the zeolite changes. One peak splits to four peaks for the 29 Si MAS NMR spectrum, and the IR vibration of framework with a high resolution become simpler. The fact indicates that there is a strong interaction between adsorbed methylamine and Si—O framework of FAU zeolite, leading to high A T value of affinity index for methylamine on the zeolite. The order structure of MA/FAU associate is discussed as well.
文摘对有模板剂和无模板剂条件下纳米 A 型和 FAU 型沸石的合成方法及生长机理进行了综述。当合成液中无模板剂存在时,所得产物中仅部分颗粒粒径小于100 nm,且粒径分布较宽;当在合成液中添加模板剂时,合成出的纳米沸石粒径均一且容易控制。纳米 A 型和 FAU 型沸石合成机理的研究表明,无模板剂时,纳米 A 型沸石由无定形凝胶颗粒的随机聚集体晶化形成,纳米FAU 型沸石由大量小晶体随机聚集形成;有模板剂存在时,纳米 A 型与 FAU 型沸石均由分散的无定形凝胶颗粒晶化形成。开发在无需添加模板剂或尽量少用模板剂的条件下制备粒径小且分布窄的纳米沸石的新方法是今后的研究方向。
