介孔材料对CO2动态吸附分离研究及数值模拟.docVIP

第 PAGE IV页 华东理工大学硕士论文 华东理工大学硕士论文 第 PAGE V页 介孔材料对CO2动态吸附分离研究及数值模拟 摘 要 气候变化问题已成为全世界关注的焦点，其主要原因是二氧化碳(CO2)等温室气体排放量的迅速增加。吸附法是高效捕集分离CO2的方法之一。本研究中，采用氨基修饰介孔材料为吸附剂，考察了其对烟道模拟气中CO2的动态吸附，以及温度、气体流速、CO2分压等不同操作条件对吸附透过曲线的影响，建立了描述CO2动态吸附分离的数学模型，模型中的吸附等温线方程包含了物理吸附和化学吸附两种方式。采用有限差分法和正交配置法将模型偏微分方程组转换为常微分方程组，分别采用Matlab中的fsolve函数和求解程序LSODE进行数值求解。通过与实验透过曲线进行拟合，获取轴向扩散系数和质量传递系数等动力学参数，在此基础上采用此模型预测了不同操作条件的透过曲线，与实验透过曲线可以较好的吻合。 高效的吸附剂是吸附法分离技术的关键。采用离子液体（[C4mim]Br/[C6mim]Br）和表面活性剂（CTAB）作为共模板剂制备多孔吸附材料，通过X-射线衍射（XRD）、透射电镜（TEM）、比表面分析（BET）对材料进行表征，结果表明在一定条件下，多孔材料可兼具介孔和微孔复合结构。通过动态光散射技术（DLS）考察了离子液体（[C4mim]Br/[C6mim]Br）和表面活性剂（CTAB）混合水溶液中胶束大小随离子液体浓度和温度的变换规律，提出了一定温度下离子液体（[C4mim]Br/[C6mim]Br）和表面活性剂（CTAB）发生微相分离，作为共模板可诱导生成微孔/介孔复合多孔材料的机理。 关键词：CO2吸附；动态吸附透过曲线；数值模拟；离子液体；微孔/介孔复合材料 Dynamic Experimental and Numerical Simulation of CO2 Adsorption on Porous Material Abstract There is a global increasing concern over the environmental impact of Greenhouse Gas emissions. CO2 capture and separation by adsorption is one of the most promising technologies. In this study, amine modified mesoporous materials were selected as the adsorbents, the CO2 adsorption at different temperatures; gas flow rates and partial pressure of CO2 were separately conducted. Based on the adsorption isotherms and adsorption kinetic curves of CO2, a mathematics model for depicting the process of dynamic adsorption separation was developed. The adsorption isotherm adopted in the model was Dual-site Langmuir, namely, chemical adsorption and physical adsorption. The partial difference equations (PDEs) for gas phase were converted algebraic equations and ordinary difference equations (ODEs), by finite difference and orthogonal collocation methods, respectively, the former was solved by fsolve function in Matlab, and LSODE for the latter. The optimal values of the model dynamic parameters, including axial diffusion coefficient and mass transform coefficient, were obtained