Soemantri Widagdo

Multiphase equilibria of reactive systems

Abstract This paper reviews recent developments in the analysis and calculation of multiphase equilibria involving chemical reactions. Emphasis is placed on the reaction tangent plane and its importance for stability analysis. Calculation methods to locate the global minimum of the Gibbs free energy are reviewed with emphasis on the GOP method that achieves ϵ-global convergence. Methods for the simulation and design of reactive-distillation columns are considered with emphasis on reactive azeotropes and reactive residue curves for chemical reactions at equilibrium or kinetically controlled.

Perspectives on chemical product and process design

Abstract In this article, new perspectives and strategies of chemical product design are provided. Beginning with the innovation map (Widagdo, S., Incandescent light bulb: Product design and innovation, Ind. Eng. Chem. Res., 45 (25), 8231–8233 (2006)) that links the critical technological advances necessary to meet customer needs, aspects of the Stage-Gate™ product-development process (SGPDP) are considered with emphasis on the concept, feasibility, and development stages. A focus is placed on the design of basic chemical products (e.g., commodity and specialty chemicals, pharmaceuticals, polymeric materials), industrial chemical products (e.g., films, fibers, paper, glass substrates, pastes, creams), and configured-consumer chemical products (e.g., light bulbs, hemodialysis devices, labs-on-a-chip). Perspectives on the role of process design in the context of product design are presented.

Azeotropic distillation with an internal decanter

Abstract A distillation column with an internal decanter is used to separate a mixture containing five some oxygenated and hydrocarbons and having at least three carbon atoms, and water. One of the species is partially miscible with water, as well as another organic species. Both binary pairs exhibit azeotropes above the minimum bubble-point temperature. The column is very sensitive to small disturbances which can lead to flooding, poor product quality, and migration of an embedded two-liquid phase region within the column. These disturbances can cause the column to move from one steady state to another for the same specifications. Multiple operating regimes are exhibited, with unusual transitions between them. Two regions involving multiple steady states are observed, one of which involves the partial-miscibility of two organic phases. The dynamics of moving interfaces between trays having one- and two-liquid phases, as well as controllers to insure that unwanted transitions do not occur, are examined.

Heterogeneous Azeotropic Distillation Involving an Embedded Two-Liquid Phase Region

Abstract An azeotropic distillation tower involving a ternary system has a built-in decanter tray with an aqueous side-draw. A steady-state model is tuned by varying the side-draw to match an experimental temperature profile. The position of the embedded two-liquid phase region is extremely sensitive to the side-draw. Dynamic simulations show sensitive movements of the interfaces in response to typical disturbances. PI controllers are utilized to expand and contract the two-liquid phase region while rejecting changes in the water composition of the feed.