为了评价碳分子筛的吸附分离性能,在四塔变压吸附装置上进行了CH4/N2混合气浓缩分离试验,研究了BM1404碳分子筛对不同浓度的CH4/N2混合气的提浓效果,以及不同吸附时间、成品气排气流量对CH4浓度、回收率和原料气处理量的影响。结果表明...为了评价碳分子筛的吸附分离性能,在四塔变压吸附装置上进行了CH4/N2混合气浓缩分离试验,研究了BM1404碳分子筛对不同浓度的CH4/N2混合气的提浓效果,以及不同吸附时间、成品气排气流量对CH4浓度、回收率和原料气处理量的影响。结果表明:吸附时间为150 s,成品气排气流量为4.20 m L/min时,分离效果最佳,可以将煤层气中的CH4含量从35%提浓到68.10%,回收率达到67.30%;BM1404碳分子筛是一种适于CH4/N2混合气变压吸附分离的吸附剂,可以将体积分数18%甲烷直接提浓到45.25%,将体积分数35%甲烷平均提浓到68.10%,将体积分数71%甲烷平均提浓到86.80%,对低中高浓度煤层气均有较佳的浓缩分离效果。展开更多
为给煤层气中甲烷与氮气的变压吸附分离提供相关的模型和热力学数据,采用静态体积法测试了温度298.15、313.15、328.15 K时,CH4/N2在自制炭分子筛上的吸附量,使用Langmuir等9个吸附模型对吸附量进行了非线性拟合,通过比较各吸附模型的...为给煤层气中甲烷与氮气的变压吸附分离提供相关的模型和热力学数据,采用静态体积法测试了温度298.15、313.15、328.15 K时,CH4/N2在自制炭分子筛上的吸附量,使用Langmuir等9个吸附模型对吸附量进行了非线性拟合,通过比较各吸附模型的拟合精度,得出最优化体积填充模型DA拟合效果最好,经验方程Freundlich模型拟合效果最差,Langmuir、Sips和Toth等模型拟合效果适中,同种模型对于N_2的拟合程度好于CH_4。同时对各模型的拟合参数进行了分析,BET方程不适合描述CH_4、N_2在该炭分子筛上的吸附,Langmuir、Toth、E-L等模型中饱和吸附量qm均随温度的升高而减小,且温度变化对于N_2的饱和吸附量影响较大;E-L模型、Toth模型和Sips模型中反映吸附剂表面能量不均匀性的参数n随着温度的升高而增大,F-L模型中分形维数D的增大表明温度升高增加了炭分子筛表面不均一性。吸附热力学分析表明,该炭分子筛对于CH_4、N_2的平均等量吸附热分别为11.80、9.06 k J/mol,均属于物理吸附;随着吸附量的增大,N_2的等量吸附热变化范围大于CH_4。展开更多
To enhance the separation selectivity of Mg-MOF-74 towards CO_(2) in a CO_(2)/N_(2) mixture,a series of Mg-MOF-74 and Ni_(x)/Mg_(1-x)-MOF-74 adsorbents were prepared by solvothermal synthesis in this paper.It was foun...To enhance the separation selectivity of Mg-MOF-74 towards CO_(2) in a CO_(2)/N_(2) mixture,a series of Mg-MOF-74 and Ni_(x)/Mg_(1-x)-MOF-74 adsorbents were prepared by solvothermal synthesis in this paper.It was found that the adsorption capacity of Mg-MOF-74 for CO_(2) could be effectively increased by optimizing the amount of acetic acid.On this basis,the bimetal MOF-74 adsorbent was prepared by metal modification.The multi-component dynamic adsorption penetration analysis was utilized to examine the CO_(2) adsorption capacity and CO_(2)/N_(2) selectivity of the diverse adsorbent materials.The results showed that Ni0.11/Mg0.89-MOF-74 showed a CO_(2) adsorption capacity of 7.02 mmol/g under pure CO_(2) atmosphere and had a selectivity of 20.50 for CO_(2)/N_(2) under 15% CO_(2)/85%N_(2) conditions,which was 10.2% and 18.02% higher than that of Mg-MOF-74 respectively.Combining XPS,SEM and N_(2) adsorption-desorption characterization analysis,it was attributed to the effect of the more stable unsaturated metal sites Ni into the Mg-MOF-74 on the pore structure and the synergistic interaction between the two metals.Density Functional Theory(DFT)simulations revealed that the synergistic interaction between modulated the electrostatic potential strength and gradient of the material,which was more favorable for the adsorption of CO_(2) molecules with small diameters and large quadrupole moment.In addition,the Ni0.11/Mg0.89-MOF-74 showed commendable cyclic stability,underscoring its promising potential for practical applications.展开更多
文摘为了评价碳分子筛的吸附分离性能,在四塔变压吸附装置上进行了CH4/N2混合气浓缩分离试验,研究了BM1404碳分子筛对不同浓度的CH4/N2混合气的提浓效果,以及不同吸附时间、成品气排气流量对CH4浓度、回收率和原料气处理量的影响。结果表明:吸附时间为150 s,成品气排气流量为4.20 m L/min时,分离效果最佳,可以将煤层气中的CH4含量从35%提浓到68.10%,回收率达到67.30%;BM1404碳分子筛是一种适于CH4/N2混合气变压吸附分离的吸附剂,可以将体积分数18%甲烷直接提浓到45.25%,将体积分数35%甲烷平均提浓到68.10%,将体积分数71%甲烷平均提浓到86.80%,对低中高浓度煤层气均有较佳的浓缩分离效果。
文摘为给煤层气中甲烷与氮气的变压吸附分离提供相关的模型和热力学数据,采用静态体积法测试了温度298.15、313.15、328.15 K时,CH4/N2在自制炭分子筛上的吸附量,使用Langmuir等9个吸附模型对吸附量进行了非线性拟合,通过比较各吸附模型的拟合精度,得出最优化体积填充模型DA拟合效果最好,经验方程Freundlich模型拟合效果最差,Langmuir、Sips和Toth等模型拟合效果适中,同种模型对于N_2的拟合程度好于CH_4。同时对各模型的拟合参数进行了分析,BET方程不适合描述CH_4、N_2在该炭分子筛上的吸附,Langmuir、Toth、E-L等模型中饱和吸附量qm均随温度的升高而减小,且温度变化对于N_2的饱和吸附量影响较大;E-L模型、Toth模型和Sips模型中反映吸附剂表面能量不均匀性的参数n随着温度的升高而增大,F-L模型中分形维数D的增大表明温度升高增加了炭分子筛表面不均一性。吸附热力学分析表明,该炭分子筛对于CH_4、N_2的平均等量吸附热分别为11.80、9.06 k J/mol,均属于物理吸附;随着吸附量的增大,N_2的等量吸附热变化范围大于CH_4。
基金supported by National Natural Science Foundation of China(U23A20100)the Strategic Priority Research Program(A)of the Chinese Academy of Sciences(XDA0390404)+5 种基金ICC CAS SCJC-DT-2023-03,the Foundation of State Key Laboratory of Coal Conversion(J24-25-619)Youth Innovation Promotion Association CAS(2018209,2020179)Key R&D Program of Shanxi Province(202102090301008,202202090301013)the special fund for S&T Innovation Team of Shanxi Province(202204051001012)Project of International Cooperation and Exchange NSFC-RFBR(22011530069)Tianjin Science and Technology Plan Project(22YFYSHZ00290)。
文摘To enhance the separation selectivity of Mg-MOF-74 towards CO_(2) in a CO_(2)/N_(2) mixture,a series of Mg-MOF-74 and Ni_(x)/Mg_(1-x)-MOF-74 adsorbents were prepared by solvothermal synthesis in this paper.It was found that the adsorption capacity of Mg-MOF-74 for CO_(2) could be effectively increased by optimizing the amount of acetic acid.On this basis,the bimetal MOF-74 adsorbent was prepared by metal modification.The multi-component dynamic adsorption penetration analysis was utilized to examine the CO_(2) adsorption capacity and CO_(2)/N_(2) selectivity of the diverse adsorbent materials.The results showed that Ni0.11/Mg0.89-MOF-74 showed a CO_(2) adsorption capacity of 7.02 mmol/g under pure CO_(2) atmosphere and had a selectivity of 20.50 for CO_(2)/N_(2) under 15% CO_(2)/85%N_(2) conditions,which was 10.2% and 18.02% higher than that of Mg-MOF-74 respectively.Combining XPS,SEM and N_(2) adsorption-desorption characterization analysis,it was attributed to the effect of the more stable unsaturated metal sites Ni into the Mg-MOF-74 on the pore structure and the synergistic interaction between the two metals.Density Functional Theory(DFT)simulations revealed that the synergistic interaction between modulated the electrostatic potential strength and gradient of the material,which was more favorable for the adsorption of CO_(2) molecules with small diameters and large quadrupole moment.In addition,the Ni0.11/Mg0.89-MOF-74 showed commendable cyclic stability,underscoring its promising potential for practical applications.
