【作者】 吕世军；

【导师】 周明；

【作者基本信息】 天津大学 ， 化学工程， 2007， 博士

【摘要】 本文首先对线性溶剂化能关系进行了分析介绍,也介绍了采用溶剂化能关系得到溶质溶剂特性参数的方法步骤,并将这些参数用于萃取精馏萃取剂的选择与优化;也通过线性溶剂化能关系式建立无限稀释活度系数预测模型,取得了一定的预测精度;将通过上述方法初选的溶剂进行了常压汽液平衡的测定研究,通过实验研究选定含水4%(占NMP质量)的N-甲基吡咯烷酮溶液做为C5分离的萃取剂,测定了大量N-甲基吡咯烷酮与C5组分的二元平衡数据,并进行关联计算;以异戊二烯为目标产物在实验室规模的精馏塔内进行了C5分离的实验研究,取得大量塔内数据;通过选用合适的热力学模型,采用ASPEN中RadFrac模块对分离过程进行模拟研究,通过实验与模拟相结合,建立了C5分离的新工艺,为将来的工业化打下了坚实的基础。主要研究内容如下:1.对线性溶剂化能关系进行了分析介绍,并详细介绍如何通过线性溶剂化能关系得到的溶剂溶质的特性参数π~*、α和β,它们分别代表溶质溶剂的偶极诱导作用、氢键酸度和氢键碱度。并将这些数据用于萃取精馏中萃取剂的选择和优化。2.运用线性溶剂化能关系提出了预测无限稀释活度系数的模型,用大量无限稀释活度系数的实验值回归出模型中的参数,最后得出用溶质溶剂特性参数值预测无限稀释活度系数的经验模型式。3.以混合C5中的正戊烷和异戊二烯为分离的代表化合物,运用上述理论进行了萃取剂的定性选择和优化。将萃取剂的选择范围集中在7种溶剂中。4.建立了一套气液平衡装置,并对实验装置进行了实验检验,结果表明此装置可用于气液平衡的测定。运用上述装置运用理论选出的7种溶剂进行分离性能的实验研究,根据实验结果和溶剂综合性能,选定N-甲基吡咯烷酮为C5分离的萃取剂;并对N-甲基吡咯烷酮进行了优化实验研究,结果表明含水4%(占NMP的质量)的混合溶剂对于C5分离效果最佳。5.对C5中的主要组分和溶剂做了常压下气液平衡的测定研究,所测数据都通过了热力学一致性检验,并用NRTL-RK方程对实验数据进行了关联,得到了C5组分与溶剂二元交互作用参数和非随机性参数,为后边的工艺计算取得了大量基础数据。6.以异戊二烯为目标产物,在实验室规模的精馏塔内进行了C5分离的实验研究。实验分两步进行:第一步采用萃取精馏分离戊烷和单烯等轻组分,实验分别研究了萃取剂用量,回流比等操作条件对分离效果的影响,并取得大量实际塔内的实验数据;第二步分离重组分时采用两种方法进行了实验研究,即萃取精馏和普通精馏方法,研究了各种操作条件对分离效果的影响。又对第二步的两种分离方法进行了比较,结果表明,采用普通精馏效果更好,且分离工艺比较简单。7.通过ASPEN中RadFrac模块首先对实验条件进行了模拟研究,结果表明对于第一步萃取精馏的模拟,热力学模型采用NRTL-RK方程,气相采用RK方程,液相采用NRTL方程,采用的模型参数大都由所测和文献数据回归得到,只有个别采用ASPEN自带参数或预测得到,模拟数据与实验数据吻合较好,此模型可用于第一步萃取精馏的模拟;第二步普通精馏,热力学模型采用Peng-Robinson方程,模拟数据与实验结果吻合较好。结果表明RadFrac模块可用与C5分离工艺的模拟优化研究。8.通过模拟研究,得到分离各步的最佳塔高,进料位置和各种操作条件;并进行了全流程的模拟优化得到聚合级的异戊二烯的各种工艺参数;通过模拟研究对分离工艺进一步深化,得到了从C5中分离出环戊烯和间戊二烯的优化工艺条件,对工艺经济性进一步优化,给过程工业化提供了依据。更多还原

【Abstract】 Linear solvation energy relation was firstly introduced in the paper, and the method and step of gaining the special parameters of solvent and solute were introduced in detail, and these special parameters were used to selection and optimization of extractive agent in extractive distillation. The model of predicting activity coefficient at infinite dilution was established by linear solvation energy relation. By the above theory, several candidate solvents were selected to separate C5 fraction, and by experiment of vapor-liquid phase equilibrium at atmosphere pressure, the mixture of N-methyl-pyrrolidone including 4% water was used extractive agent of separating C5 fraction. Then binary vapor-liquid phase equilibrium of the some compound in C5 fraction and N-methyl-pyrolidone were determined at atmosphere pressure and correlated by NRTL equation. Isoprene being objective compound, experiments were operated in the laboratory-scale column; the processes were simulated by RadFrac model in ASPEN PLUS. And by the combination of experiment and simulation, the new process of separation of C5 was established. In the paper, the main works were as follows:1. Linear solvation energy relation was firstly introduced, the special parameters of solvent and solute which wereπ~*、αandβwere also introduced, the scale ofπ~* described the ability of solvent-solute action by dipolarity and polarization; Theαscale of solvent/solute HBD (hydrogen-bond donor) acidity described the ability of solvent/solute to donate a proton in a solvent-to-solute hydrogen bond; theβscale of solvent/solute HBA (hydrogen-bond acceptor) basicity described the ability of solvent/solute to accept a proton in a solvent-to-solute hydrogen bond. By these special parameters extractive agent was selected and optimized qualitatively. 2. The model of predicting activity coefficient at infinite dilution wasestablished by linear solvation energy relation, and the unknown parameters in the model were gained by linear correlation of abundant experimental values of activity coefficients at infinite dilution.3. The mixture of n-pentane and isoprene was model mixture in C5 fraction, by above selection and optimization of extractive agent theory, 7 kinds of solvents were used as candidate solvents.4. The vapor-liquid equilibrium equipment was set and was checked by literature values, the results showed the equipment could be used to determine vapor-liquid equilibrium at atmosphere pressure. The mixture of n-pentane and isoprene was used model mixture of C5 fraction, and effect on separation of the mixture of 7 solvents were studied by experiment, by combination of separation effect and other characteristics such as toxicity, stability, and so on, N-methyl-pyrrolidone was selected as extractive agent of the separation process of C5 fraction. The optimization of N-methyl-pyrrolidone was studied by vapor-liquid equilibrium experiment, and the result showed the mixture of N-methyl-pyrrolidone including 4% water could be better extractive agent than others.5. Vapor-liquid equilibrium of the important compound and N- methyl-pyrrolidone at atmosphere pressure was performed, and all values passed the thermodynamics consistency test by Herington method. These values also correlated by NRTL and RK equations; the binary interaction parameters and nonrandom factors in the NRTL equation were gained. These datum were the base of simulation.6. Isoprene being objective output, the experiments were performed in the laboratory-scale column. The process was two steps: the first step was extractive distillation, in the step some operation conditions were studied and gain a lot of experimental values; in the second step, ordinary distillation and extractive distillation were performed, respectively, some operation conditions were performed and a lot of data were gained. By comparing the separation effect of two method in the second step, the ordinary distillation was used because separation effect and simplicity.7. The experimental conditions were simulated by RadFrac in ASPEN PLUS, and the thermodynamics models were NRTL and RK equation in liquid phase and vapor phase, respectively, in extractive distillation process while the model was PR equation in the ordinary distillation, the calculated values agreed with the experimental values. RadFrac was used to simulate and optimize the separation processes of C5 fraction by above thermodynamics models.8. By simulation, the optimal operation conditions were gained in every step in the separation process, and polymerization-class isoprene was gained by the process. And to improve the economy of process, the process was studied by simulation, 99% cyclopentene and 1, 3-pentadiene were gained by continuous separation process. All were the base of the process industrialization.更多还原