Performance of reactive distillation columns with multiple reactive sections for the disproportionation of trichlorosilane to silane
With reference to the disproportionation of trichlorosilane to silane, a three-stage consecutive reversible reaction with a rather unfavorable reaction kinetics, in-depth comparison in steady-state performance is performed between the column with a single reactive section and those with multiple reactive sections, adopting the equal number of trays and the equal amount of catalyst. The reactive distillation column with multiple reactive sections appears to be considerably superior in the aspect of economic advantages to the reactive distillation columns with single reactive section and these strengths originate essentially from the additional degrees of freedom resulted from the arrangement of multiple reactive sections in process synthesis and design. Arrangement of side-condensers is also examined towards the columns with multiple reactive sections and the outcomes reveal the thermodynamic rational to adopt multiple reactive sections in process development. Although these findings are derived from the specific case study chosen, it should be regarded as the significant potential for analyzing the reactive distillation columns with intricate multiple reversible reactions and separating intricate multiple components.
Synthesis and design of reactive distillation columns with two reactive sections
Abstract The synthesis and design of reactive distillation columns with two reactive sections (RDC–TRS) are attempted for the separations of reacting mixtures with somewhat unfavorable ranking of relative volatilities (RM–SURRV, i.e., two reactants are the light and heaviest components and two products the lightest and heavy ones). With the deliberate arrangement of the two reactive sections, the disadvantages by the unfavorable relative volatility can be substantially alleviated, facilitating consequently the reaction operation and separation operation involved. The separations of a hypothetical quaternary reaction, the esterification of acetic acid with methanol, and the transesterification of butyl acetate with ethanol are employed to evaluate the RDC–TRS. The process is found considerably superior to the reactive distillation column with a single reactive section and this demonstrates its feasibility and effectiveness in the separations of RM–SURRV. The RDC–TRS is found to present comparable or even improved performance in comparison with the reactive distillation column with an external recycle from bottom to reactive section and this corroborates it a potentially competitive alternative for the separations of the RM–SURRV. The RDC–TRS is also highlighted for the other kind of RM–SURRV (i.e., two reactants are the lightest and heavy components and two products the light and heaviest ones).
Plantwide Design of Transesterification Reactive Distillation to Co-Generate Ethyl Acetate and n-Butanol
Reactive distillation (RD) in the face of azeotrope(s) in the separation of a mixture from an RD column might need debottlenecking design and more columns to obtain high-purity products. Under such circumstances, the integration of heat with the process becomes an effective consideration for reducing costs. In this study, an RD process to produce ethyl acetate and n-butanol from ethanol and n-butyl acetate by conducting a transesterification reaction is presented. The products from the RD column include n-butanol and an ethanol/ethyl acetate mixture. Designs with alternative configurations are used to illustrate plantwide designs of the process with heat integration/coupling. Among these alternatives are two with three columns and one with two columns. In the three-column configurations, separation of ethanol/ethyl-acetate mixtures from the top product of the RD column is conducted by extractive distillation or pressure-swing distillation. The other configuration consists of an RD column followed by a con...