Modeling of Partial Hydrogenation of Polyunsaturated Fatty Acid Methyl Esters in a Trickle Bed Reactor

Abstract

Partial hydrogenation of polyunsaturated fatty acid methyl esters in a trickle-bed reactor was modeled and simulated in this study with the objectives being to investigate the performance of the reactor, to predict the effect of process parameters on the reactor performance, and to observe the radial heat transfer in the reactor. The reactor possessed the aspect ratio of 100 and was packed with spherical catalyst particles. A steady-state heterogeneous model was applied. The gas and liquid phases were modeled in two-dimensional axisymmetric model, which consist of mass balance for each phase, energy balance and momentum balance. The momentum balance was based on the Darcy equation for two fluid phases passing through porous media. Mixing in both fluid phases is also described by dispersion coefficients. The three-dimensional solid phase model considered diffusive transport in the catalyst pores and surface reactions. Methyl linoleate was considered as polyunsaturated fatty acid methyl ester representative, and cis-methyl oleate, trans-methyl oleate and methyl stearate were as the hydrogenated fatty acid methyl esters. The simulation results for the inlet temperature of 433 K and the reactor pressure of 611 kPa with the gas flowrate being 43 times higher than the liquid one shows that the process reached 78.22% methyl linoleate conversion. The concentrations of cis-methyl oleate, trans-methyl oleate and methyl stearate at the reactor outlet are 16.2 mol/m³, 17.4 mol/m³ dan 16.6 mol/m³, respectively. The total methyl oleate produced is about twice that of methyl stearate, and its selectivity is about 53%.