No abstract

Chromatographic reactor is an attractive mode of operation that combines chemical reaction and product separation in the same unit. In this work, esterification of butyl cellosolve with acetic acid using cation exchange resin Amberlyst-15 is investigated in a chromatographic reactor. The study involves determining the appropriate kinetic model for the reaction by performing experiments at different temperatures, mole ratios of the reactants, catalyst loadings and stirring speeds. Characterization of the adsorption capacity of the resin for different components involved in the reaction is performed through adsorption experiments for the nonreactive binaries. The combined separation-reaction process is experimentally investigated using a fixed bed chromatographic column. A mathematical model is developed and the experimental data is compared with the model predictions. It is shown that the experimental and predicted data closely follow each other and that the high conversion can be obtained with a relatively high purity of the product.

Reactive chromatography (RC) is a promising technology, wherein equilibrium limitations are overcome by simultaneous reaction and adsorptive separation in a single unit. This operation, on a large scale, can be performed conveniently in a simulated moving bed reactor (SMBR) in continuous mode. In this work, we demonstrate the use of an SMBR for the synthesis of 2-ethylhexyl acetate through experiments and simulations. The kinetic model and Langmuir adsorption isotherm, which serve as inputs to the simulator, were taken from an earlier study Mahajani Sep. Sci. Technol. 2008, 43, 2245). A parametric study was performed using the experimentally validated simulator by varying one of the parameters at a time, to yield desired performance in terms of conversion, purity, productivity, and desorbent consumption. The trends in the results are explained with the help of variations in the solid and liquid concentrations. The simulation results indicate that an SMBR unit containing eight columns is able to offer almost quantitative conversion and purity with a typical desorbent requirement of 46.35 mol of acetic acid per mole of product and a productivity of 32.01 mol of product per kilogram of adsorbent per day. Further optimization of the performance and application of a systematic design algorithm are developed and presented in part II of this work.

A simulated moving bed reactor (SMBR) is a multifunctional reactor wherein the reaction and chromatographic separation take place simultaneously. The positions of the inlet and outlet ports are switched at periodic intervals to simulate a true moving bed system. The design exercise for these units is a challenging task due to the large number of degrees of freedom such as the column volume, SMBR configuration (i.e., number of beds in each section), sectional flow rates, switch time, desorbent concentration and feed concentration. In this work, we propose a simulation based design methodology for the SMBR process that is employed for heterogeneously catalyzed reversible reactions, in which one of the reactants works as a solvent and the catalyst also plays the role of adsorbent. The objectives are productivity (PR) maximization and desorbent consumption (DC) minimization which have a direct impact on the total annualized cost of the process. The performance parameters such as conversion, raffinate purity, and extract purity are chosen as constraints. The model reaction considered is the esterification of acetic acid with 2-ethylhexanol catalyzed by cation exchange resin.