【作者】 刘迎；

【导师】 王英龙；

【作者基本信息】 青岛科技大学 ， 化学工程， 2013， 硕士

【摘要】 可再生基质发酵产生的发酵液中含有大量高热值的低碳醇(C2-C5醇)类化学品,这些化学品是一种前景看好的化石燃料能源的替代品,它们的开发利用是解决化石燃料使用所带来的能源危机的有效途径之一。然而,上述体系成分复杂导致的高分离成本限制了该类可再生能源的工业化应用。液液萃取是低碳醇-水体系分离的有效手段之一,测定该类体系的液液相行为并进行热力学模拟具有重要的意义。本文研究了发酵液中所含部分低碳醇与水构成的三元体系的液液平衡(LLE)并探究了温度对它们的影响。利用配有Porapak Q-S80/100型号填充柱的GC-14C气相色谱仪测定了不同温度下正丁醇-异戊醇-水、异丁醇-异戊醇-水、异丁醇-异丙醇-水、异丁醇-正戊醇-水四个三元体系的常压LLE连结线数据。采用著名的Othmer-Tobias、Bachman和Hand方程检验了实验数据的可靠性,三个方程的关联精度R2均大于0.94。绘制不同温度下的三元LLE相图,其中,异丁醇-异丙醇-水体系呈现出Treybal Ⅰ型相图,正丁醇-异戊醇-水、异丁醇-异戊醇-水和异丁醇-正戊醇-水体系呈现出Treybal Ⅱ型相图。温度对上述体系混溶区和非混溶区面积的影响规律：温度对正丁醇-异戊醇-水和异丁醇-异戊醇-水体系的混溶区和非混溶区的面积影响较大,而对异丁醇-异丙醇-水和异丁醇-正戊醇-水体系的影响较小。为得到用于模拟计算的可靠的二元交互作用参数,采用基于局部组成为概念的非随机双液体(NRTL)和普遍的准化学(UNIQUAC)活度系数模型,对等温下的LLE实验数据进行参数回归,得到所研究物系内相应组分之间的二元交互作用参数。将回归的预测值与实验值进行比较,所测定的每个物系的均方根偏差(RMSD)均小于0.01,预测值与实验值的吻合程度较高,表明两种模型都可以用来模拟研究体系的LLE。本文研究的低碳醇-水体系的三元LLE数据为低碳醇类生物质发酵液高效分离与有效利用奠定基础,得到的相应模型参数值可用于该类溶液的LLE计算及相关分离过程的设计。更多还原

【Abstract】 There are many lower alcohols (C2-C5alcohols) chemicals with high heating value in fermentation broth generated by the fermentation of renewable materials, and these chemicals are a promising alternative to fossil fuel energy. The development and utilization of which will be one of an effective ways to solve the energy crisis brought by the use of fossil fuels. However, the industrial application of this kind of renewable energy is limited by the complicated composition of the above system resulting in high separation costs. The separation for the system containg lower alcohols and water can be performed by liquid-liquid extraction that is an effective means. The determination of liquid-liquid phase behavior and thermodynamic modeling for these kinds of system will be of great importance.Liquid-Liquid Equilibrium (LLE) phase behaviors for the ternary systems consisting of some lower alcohols and water in fermentation broth were studied. In addition, the influence of temperature on the above systems was investigated in this paper. LLE tie-line data (mole fraction) for four ternary systems1-butanol+3-methyl-1-butanol+water,2-methyl-l-propanol+3-methyl-1-butanol+water,2-methyl-1-propanol+2-propanol+water, and2-methyl-l-propanol+1-pentanol+water at different temperature under atmospheric pressur were determined by using GC-14C gas chromatograph packed with Porapak Q-S80/100column. The famous Othmer-Tobias, Bachman and Hand equations were applied to examine the reliability of the experimental data, and the correlated accuracy (R2) values for all of the three correlations were more than0.94. LLE phase diagrams for the above ternary systems at different temperature were drawed. The equilibrium phase diagram for2-methyl-l-propanol+2-propanol+water was Treybal’s type I phase diagram, and type II LLE phase diagrams could be seen for the studied systems of1-butanol+3-methyl-1-butanol+water,2-methyl-1-propanol+3-methyl-1-butanol+water, and2-methyl-l-propanol+1-pentanol+water. The influence rule of temperatures on the area of miscibility region and immiscibility region were summarized as the temperatures among the studied range had great influence on that for1-butanol+3-methyl-1-butanol+water and2-methyl-l-propanol+3-methyl-1-butanol+water, while had little effect on that of the systems2-methyl-l-propanol+2-propanol+water and2-methyl-l-propanol+1-pentanol+water.LLE experimental data at constant temperature were regressed by using the non-random two liquid (NRTL) and universal quasi-chemical (UNIQUAC) activity coefficient models based on the concept of local composition aiming at obtaining reliable binary interaction parameter for simulation calculation, and the binary interaction parameters between the corresponding components in the studied ternary systems were reported. It could be found from the comparisons between the regressed values and the measured values that all of the values of root-mean-square deviation (RMSD) for each of the systems were less than0.01, that is to say, both of them agreed well with each other. The good results indicated that both of the models could be used to simulate LLE of the investigated systems.The tenary LLE data for studied systems including lower alcohols and water will lay the foundation for the highly efficient separation and effective utilization of biomass fermentation broth containing lower alcohols. The corresponding model parameters can be used to calculate LLE data and design related separation process for this kind of solution.更多还原