Thymol Hydrogenation in Bench Scale Trickle Bed Reactor

J. Dudas, J. Hanika, J. Lepuru and M. Barkhuysen

Abstract
Investigation of thymol hydrogenation was a part of novel L-menthol process development. The main objective of the investigation was to collect experimental data for the scale up of thymol hydrogenation in a trickle bed reactor. Hydrogenation of thymol was performed in an adiabatic bench scale trickle bed reactor on alumina supported Nickel catalyst. The design parameters of the bench scale system were as follows: maximum pressure 3.5 MPa, maximum temperature 350 °C, liquid flow rates of 0.5 to 5 kg h–1. The experiments were performed at different thymol mass fraction (10 to 40 % wt.) in liquid menthols mixture as solvent, liquid flow rates (LHSV of 0.8 to 3.6 h–1), hydrogen flow rates (QL = 23 – 4 6 g h–1) and with total pressures of between 0.9 and 1.5 MPa. Catalyst lifetime was measured for 660 hours with the total thymol/catalyst loading being 206.5 kg kg–1. It was found that, trickle bed reactor at adiabatic conditions is feasible option for thymol hydrogenation, and for safe scale-up the maximum thymol mass fraction in the feed should be below 15 % wt.

This work is licensed under a Creative Commons Attribution 4.0 International License

Keywords
Thymol hydrogenation, trickle bed reactor, gas-liquid-solid reaction