A Simplification Procedure for Distillation Tray Models

Abstract

The popularity of liquid separation by distillation in the industry has resulted in a wide range of distillation models. These models range from detailed flow models used in the design of trays and packings, to models concerned with idealized column operation and design. The different models are presented throughout the literature as occupying separate model categories, whereby the category of model that is applied depends on the behavior of the fluid and the goal of the model.

This thesis shows that it is possible to move between different models and their model categories. This is done by constructing a complex preliminary model from which all other models can be derived. Each model is derived in sequence as a simplification of the previously defined model. In order to allow for such a step by step model derivation, it is assumed that all models can be described as volumes interacting through transfer.

This view of the model allows us to visualize each model as a physical topology. The physical topologies are used to give the reader an intuition of the physical system and what kind of models that can apply to such a view of the system. Topologies gives practical insight into what kind of simplification that can be made in the next step. This is done by identifying the part of the topology that is considered complex.

This thesis is a study on the different kinds of distillation models there are and how they are connected through simplifying assumptions. Each model is in turn documented and all simplifying assumptions are made clear.