ISBN 9783843913904

978-3-8439-1390-4, Reihe Ingenieurwissenschaften

Carlos Alberto Gonzalez Rugerio
Reactive distillation for the production of high-octane gasoline components

178 Seiten, Dissertation Technische Universität Dortmund (2013), Softcover, B5

Zusammenfassung / Abstract

Reactive distillation (RD), in which chemical reaction and distillation are integrated into a single apparatus, has shown remarkable improvements when compared to sequential reaction-separation processes due to synergy effects. RD has been implemented at a commercial scale for the production of the gasoline octane enhancer, methyl tert-butyl ether (MTBE). However, due to environmental concerns, MTBE has been banned in several countries, and, hence, there is a growing interest to replace it. Tert-amyl ethyl ether (TAEE), di-methyl carbonate (DMC) and di-ethyl carbonate (DEC) are considered to be potential candidates for use in gasoline in the near future due to their excellent gasoline blending properties.

In this work, the analysis of RD for the production of TAEE, DMC and DEC is performed. For the synthesis of TAEE, a stream taken directly from a refinery was used as a feedstock, and consequently, the complexity of the modelling step increased significantly. In this context, two research questions were addressed: a) the key components and chemical reactions to be included in the simulations and b) the procedure used to select the key components.

RD models at steady and dynamic state were developed and validated with experimental data measured in pilot-scale columns. A comparison of simulation results using two RD process models of different complexity with experimental data allowed determining the adequate modelling depth for each chemical system.

A method to design cost-optimal catalytic distillation columns for chemical systems involving a large number of components and chemical reactions was developed. The method was applied stepwise to design a column for the synthesis of TAEE.

The dynamic responses of the RD column to process disturbances were investigated. Moreover, a theoretical analysis of the multiplicity of steady states was performed. The source of the multiplicity was investigated via simulations using models of different complexity, and the stability of each steady state was studied via dynamic simulations.

For all chemical systems investigated in this work, the benefits of RD include overcoming chemical equilibrium and selectivity limitations that occur in sequential processes. However, for DMC and TAEE, it is not feasible to obtain high product purities in a single column. In the former case, as a consequence of a DMC-containing azeotrope, while for TAEE due to the presence of heavy components in the column feed.