Modernization of Industrial Technology for Dehydrogenation of Methylbutenes to Isoprene. Part I. Mathematical Analysis of Options to Upgrade the Technol

Abstract

To determine a most energy-efficient method for technology modernization, a mathematical modeling of a number of technologies for dehydrogenation of methylbutenes was performed. The traditional technology (the process in an adiabatic reactor) was compared with the following three embodiments of the process in the «pseudo-isothermal» mode: 1) a single-reactor scheme with a fractional supply of steam to the upper and middle parts of the catalyst layer; 2) a consecutive two-reactor scheme with intermediate heating of a contact gas in an interstage superheater; 3) a consecutive two-reactor scheme with the addition of superheated steam into an interreactor volume. It is shown that each of the new schemes can significantly increase the process effeciency compared with the conventional technology. A comparative analysis of the dependence of the yield and selectivity toward isoprene on the thermal energy Q fed in the modified schemes has shown that the highest increase in the yield of isoprene (5,5 %) and selectivity (5,6 %) at large contact times is provided via Scheme 2, especially when Q > 8,5 ·106J/kg.