The D+r Tray: Novel Laboratory Equipment for Studying Heterogeneously Catalyzed Reactive Distillation – Design and Simulation-based Validation

In this paper, novel equipment for laboratory studies of heterogeneously catalyzed reactive distillation is described. The so called D+R tray equipment consists of a combination of conventional bubble cap trays with sections that are filled with catalyst and through which the liquid flows when it passes from one distillation tray down to the next. It is designed so that the catalyst can be easily changed, and its amount can be flexibly chosen. These are important advantages compared to catalytic packings. In the present study, D+R tray equipment built in glass in the 50 mm diameter scale was investigated. In order to proof the general functionality of the D+R tray, the fluid dynamic capacity and the tray efficiency of the distillation section as well as the residence time distribution (RTD) of the reactive section were systematically investigated in a series of preliminary tests. Afterwards, the D+R trays were tested in a comprehensive series of reactive distillation experiments. For these experiments, two test systems were chosen that had been studied thoroughly in previous work in different scales with catalytic packings. The most important process parameters such as feed rate and amount of catalyst were systematically varied. High conversions of the reactants and high purities of the products were achieved. The reproducibility of the results is excellent. That proves the general performance and operability of the D+R tray equipment. Process simulations were carried out using a stage-based model. The process model is based on carefully validated models of the physico-chemical properties of the test systems from previous works. The tray efficiency was not adjusted but taken from the independent measurements so that the simulations are predictive. The comparison with the experimental data shows good agreement. With the same model, HCRD experiments carried out in previous work on the same test systems with catalytic packings are well described. This shows that experiments carried out with D+R tray equipment can be used for studying designs of HCRD processes with either catalytic packings or trays.