Production of sec-butyl alcohol by olefin hydration - a candidate for process intensification?
Special Symposium - EPIC-1: European Process Intensification Conference - 1
EPIC-1: Poster Session (EPIC - Poster) - P2
Keywords: process intensification, liquid-liquid-solid reaction, olefin hydration, extraction, kinetic studies
Production of sec-butyl alcohol by olefin hydration – a candidate for process intensification?
B. Pfeuffer, D. Petre, U. Kunz, U. Hoffmann, T. Turek, D. Höll*
Institute of Chemical Process Engineering, Clausthal University of Technology,
Leibnizstr. 17, 38678 Clausthal-Zellerfeld, Germany
* Sasol Solvents Germany GmbH, Römerstr. 733, 47433 Moers
The production of lower alcohols by direct hydration of olefins with acidic ion exchange resins as catalysts is a process used in industry since many years [1]. An example for a liquid-liquid-solid process is the production of sec-butyl alcohol from linear butylenes and water. The alcohol forms inside a well wetted resin catalyst. Superimposed to the chemical reaction is the extraction of the alcohol into the olefin phase while the low olefin solubility in the water phase determines the global rate of alcohol formation. To investigate the involved phenomena in this process a laboratory reactor system was developed which allows performing kinetic experiments with respect to chemical reaction and mass transfer in this three phase system.
In this project a continuous stirred Carberry type tank reactor with baskets attached to the stirrer shaft is used [2]. The baskets contain catalyst and rotate on the stirrer shaft agitating the multiphase reaction mixture to a grey coloured emulsion. The discharging reaction mixture is separated and each phase is sampled by two special sample injectors for online GC analyses. A second analytical system is a FTIR-ATR-spectrometer directly mounted to the tank reactor which allows in situ measurements with high sample rates of the reaction or the liquid-liquid mass transfer and the supercritical-liquid mass transfer, respectively. The mass flows of the water and olefin feed streams are measured by thermal mass flow meters, while the water exit stream is determined by a coriolis mass flow meter.
Mass transfer limitations were observed to determine the kinetic regime of the chemical reaction by varying the temperature, agitation speed and the catalyst pellet size. Details of the running kinetic experiments will be given.
Theoretical examinations clarify that the olefin has to pass through the water phase until it reaches the active sites. Model calculations show a quasi-instantaneous consumption of the low olefin load in the water phase. The low solubility and transport of the olefin into the water phase lowers the chemical reaction rate significantly. Furthermore, in this case the multi phase operation of a fixed catalyst bed leads to strong hydrodynamic difficulties sharpening the mass transfer issue. Proposals for process intensification, circumventing the mentioned limitations, will be discussed.
[1] W. Neier, J. Wöllner, “Use cation catalyst for IPA”, Hydrocarbon Processing, Nov., (1972), 113-116
[2] J.J. Carberry, “Designing Laboratory Catalytic Reactors”, Industrial & Engineering Chemistry 56, 11 (1964), 39-46
Presented Thursday 20, 13:30 to 14:40, in session EPIC-1: Poster Session (EPIC - Poster) - P2.
