New Tools for the Computer-Aided Design of Nonideal Distillation Systems

近年来，计算机辅助工艺设计领域取得了长足的进步。在这些最新的发展中，有一些是设计复杂工业系统的新方法。开发这种工程工具具有经济动机，只要它们简单、准确，并且能够在项目生命周期的早期就区分工艺备选方案，以便消除不安全、不可控和不经济的设计。到目前为止，商业和学术都感兴趣的一个领域还没有被成功地解决，那就是设计非理想的多组分蒸馏系统。当工艺流形成理想的混合物时，现有的概念设计方法提供了有效的手段，将可能的精馏序列缩小到少数有希望的替代方案。然后，可以使用基于模拟器的技术进行更详细的设计和成本计算。然而，对于非理想和共沸混合物，在不进行广泛的全面计算机辅助模拟和成本计算的情况下，没有程序或工具来选择不同的非理想精馏序列。PI计划开发一类新的技术，用于非理想和共沸精馏系统的计算机辅助分析、设计和综合。该方法利用了组成状态空间中稳态组成分布的非线性离散动力系统表示的几何性质。该程序可以扩展到包括多组分反应蒸馏塔。该技术还提供了一种程序，用于确定回流比高于最小回流比的每个塔段的最小流量和理论级数，而不需要像目前的做法那样进行冗长的迭代。PI计划着眼于商业上的重要情况，包括非尖锐的分裂、多进料柱和切线挤压。

The area of computer aided process design has advanced substantially in the recent past. Among some of these recent developments are new methods to design complex industrial systems. There is an economic incentive to develop such engineering tools provided they are simple and accurate and are able to discriminate between process alternatives very early in the life of a project in order to eliminate designs that are unsafe, uncontrollable, as well as uneconomic. An area of both commercial and academic interest which has not been successfully addressed to date is the design of nonideal, multicomponent distillation systems. When the process streams form an ideal mixture, existing conceptual design methods provide efficient means for narrowing down the possible distillation sequences to a small number of promising alternatives. These can then be designed and costed in more detail using simulator-based techniques. For nonideal and azeotropic mixtures, however, there exist no procedures or tools for choosing between different nonideal distillation sequences without carrying out extensive full-scale computer aided simulations and costing. The PI plans to develop a new class of techniques for computer aided analysis, design and synthesis of nonideal and azeotropic distillation systems. The methods exploit geometric properties of the nonlinear discrete dynamical system representation of the steady state composition profiles in the composition state space. The procedure can be extended to include multicomponent reactive distillation columns. The technique also provides a procedure for determining the minimum flows and the number of theoretical stages in each column section for reflux ratios above the minimum without the necessity of lengthy iterative schemes, as is the current practice. The PI plans to look at commercially important situations including non-sharp splits, multiple-feed columns, and tangent pinches.