A Novel Routine for Manufacture of Environmentally Friendly Ethanol Fuel via Reactive Distillation

A novel routine for removing water from ethanol by the hydration using C4 olefin cut catalyzed with the ion exchange resin was proposed. Reactive distillation experiments were carried out to demonstrate the feasibility of this routine. The sensitivity analysis was performed by using the software of ASPEN PLUS 10.2. The optimized operating conditions were obtained considering three objective functions which were the water content of the bottom product, water conversion rate and hydration selectivity. Under the optimized operation conditions, the final product was consisted of 45.0% of ethanol, 19.4% of ethyl tert-butyl ether, 35.1% of tert-butyl alcohol and 0.6% of water in volumetric percentage.     

反应精馏过程中的多稳态分析

Reactive distillation processes for synthesis of ethylene glycol （EG） and ethyl tert-butyl ether （ETBE） were modeled with the simulation package ASPEN PLUS. The input multiplicity and output multiplicity were discussed with the method of sensitivity analysis for both cases. In EG production process, steady state multiplicities were studied in terms of effective liquid holdup volume and boil-up ratio. In ETBE synthesis process, the user kinetic subroutine was supplied into ASPEN PLUS firstly, and then the composition, temperature and reaction-rate profiles within the reactive distillation column were presented in detail. A set of stable solution branches based on distinct initial guesses for a range of boil-up ratio were found in EG synthesis. Input multiplicities were observed for a range of reboiler duty at several values of reflux ratio for ETBE synthesis process. These results can be used to avoid excessive energy consumption and achieve optimum design of reactive distillation column.     

流化催化裂化轻汽油组合式醚化工艺的模拟

提出了预反应与反应精馏相结合,预反应器环境适合C6烯烃醚化,反应精馏塔环境适应C5烯烃醚化的组合式FCC轻汽油醚化新思路.运用过程模拟软件Aspen Plus 10.2,对上述组合式醚化新工艺进行了模拟优化分析.模拟时采用平衡级模型RadFrac作为反应精馏模型,并使用Visual Fortran 6.5编写了动力学子程序接口.其中的相平衡计算,采用了UNIF-DMD活度系数模型,对于Aspen数据库中缺失而又鲜有文献报道相关组分的热力学性质,采用了Bcnsonhe Joback等基团贡献法进行了估算,得到了常压下各叔烯烃不同温度下醚化反应的Gibbs自由能变化以及各醚化反应的平衡常数.结果证实,在优化的工艺操作条件下,组合式FCC轻汽油醚化工艺,可以解决现行醚化工艺烯烃转化率较低的问题,使FCC轻汽油产品可使烯烃体积分率从42.40%降低至25.40%,辛烷值提高2.74个单位.     

基于超熵产生分析的反应精馏系统多稳态研究(Ⅱ)稳定性分析

以环氧乙烷与水合成乙二醇为模型体系进行了实例分析,得到了该反应精馏系统在一定条件下的多定态解,利用超熵产生判据式对各定态解的稳定性进行了分析,在此基础上进一步讨论了多稳态产生的原因.结果表明:浓度涨落、温度涨落、其他操作负荷的变化以及反应动力学特性都可以成为反应精馏系统出现多稳态的原因.将超熵产生判据用于反应精馏体系定态稳定性的判定,较为可靠.因为超熵产生判据式是由热力学基本原理推导而来,较好地反映了反应精馏过程演化的非线性不可逆的热力学本质,因此本方法对反应精馏系统稳定性的研究,具有普遍的理论指导意义.     

基于超熵产生分析的反应精馏系统多稳态研究（Ⅰ）定态稳定性判据模型的建立

为对反应精馏系统中的多稳态现象进行深入分析,提出了利用超熵产生进行定态点稳定性分析和判定的新思路.根据反应精馏质热传递的特征以及熵流熵产分析,建立了该过程的热力学模型;定义系统的二阶变分为超熵,由非平衡热力学定态点的里亚普罗夫稳定性分析理论,取二级超熵δ2S为里亚普罗夫函数,将此函数对时间求导,得到了系统的超熵产生;将系统在扰动情况下的变化转化为超熵产生的变化,根据超熵产生的正负性即可判断系统的稳定性.     

基于多场协同理论的渗透蒸发传质模型

Toprovide a theoretical basis for optimizing the pervaporation procedure, a mass transfer model for pervaporation for binary mixtures was developed basedon the multi-fields synergy theory. This model used the mechanism of sorption-diffusion-desorption and introduced a diffusion coefficient, which was dependent on the feed concentration and temperature. Regarding the strong coupling effect in the mass transfer, the concentration distribution in membrane was predicted using the Flory-Huggins thermodynamic theory. The batch experiments and other experiments with constant composition-were conducted-using a modified chitosan pervaporatioffmembrane to separate tert-butyl alcohol （TBA）-water mixtures. The parameters of the mass transfer model were obtained from the flux of the experiments with a constant composition and the activity coefficients available through phase equilibrium equation, using the Willson equation in the feed side and the Flory-Huggins thermodynamic theory within the membrane The simulation results of the experiments .are in good agreement with the results, of the experiments.