Hartmut Schoenmakers

Synthesis of n-hexyl acetate by reactive distillation

Abstract Comprehensive studies on the n-hexyl acetate synthesis by heterogeneously catalyzed reactive distillation are presented. Reactive distillation experiments were carried out both in laboratory and semi-industrial scale with different catalytic packings. Several variants of a basic column set-up and the influence of the most important process parameters were studied. Additionally, phase and chemical equilibria and reaction kinetics were measured. Predictions from stage models of different complexity are compared to the results of experiments. It is shown, that, based on a sound knowledge on reaction kinetics and thermodynamic properties it is possible to successfully describe the studied reactive distillation process.

Feasibility and multiplicity in reaction–distillation processes for systems with competing irreversible reactions

Abstract Several important technical reaction systems consist of competing irreversible reactions of the type A+B→C and A+C→D, in which C is the product and D is an undesired byproduct. To produce C from A and B, a conventional process using a reactor coupled with a distillation column to recycle unreacted educts can be used. An alternative is reactive distillation. In the present paper, a simple mathematical model for the conventional reaction + distillation process is developed (second-order reaction kinetics +∞/∞-analysis of the distillation column). This model is used to comprehensively investigate the feasibility and multiplicity of the process, a task which would be too time consuming using rigorous simulators. The entire range of different combinations of process variables which allow a desired selectivity (C/D) to be obtained is explored and it is shown for which combinations of input variables which types of multiple solutions (output) will occur. As all solutions are obtained analytically, it is possible to give a complete picture of the stationary system behavior including all transitions between the different types of solutions. An interpretation of the different kinds of multiplicity observed in the present process is given. The basic features of the solutions presented here should also hold for the reactive distillation process.

CAPE in der Praxis - Möglichkeiten und Grenzen aus Nutzersicht: CAPE in der Praxis - Möglichkeiten und Grenzen aus Nutzersicht

CAPE (Computer Aided Process Engineering) tools comprise computer based tools and methods for the design of chemical processes - the use of which is indispensable in modern chemical engineering. This paper discusses the degree to which CAPE is already applied and whether limitations exist. Within BASF, the CAPE framework is provided by the ProcessNet, which integrates numerous simulation and design tools. The engineer relies alternatively on inhouse or commercial software. The advantage of CAPE in terms of efficiency depends not only on complex programs, but also to a large extent on the multiple use of intermediate data and program modules. The ProcessNet also features a hierarchical file structure to support the engineers desktop management. The CAPE environment is being continuously improved. The main constraints on CAPE today are, for example, the missing link between fluid and solid applications, a deficit in data management and the poor state of development of advanced or special programs. The progress of research in this area is followed with great interest.