Simulation of packed bed reactors using lattice Boltzmann methods

Abstract

Lattice Boltzmann (LB) methods are used to simulate hydrodynamics, reaction and subsequent mass transfer in a disordered packed bed of catalyst particles at sub-pore length-scales. In contrast to previous studies, a variety of modifications are introduced in the LB method enabling particle Pe numbers up to 10 8 , and hence realistic values of diffusivity, to be accessed. These include decoupling the hydrodynamics from mass transfer and the use of a rest fraction in the LB formulation of mass transfer. In addition the mass transfer simulations are modified to permit spatially varying values of diffusivity, essential to differentiate between intra- and inter-particle diffusivity ( D intra and D inter , respectively). The simulation method is applied to both a disordered and ordered 2D packing for a range of Pe (15.6–1557.8) and Re (0.16–1.56) numbers, as well as various ratios of D intra / D inter (0–1), whilst simulating an esterfication reaction catalyzed by an ion-exchange resin. The value of D intra is found to have limited effect, whilst reducing Pe number results in a considerable increase in overall conversion. The simulation method is then applied to a 3D lattice for which experimental conversion data is available. This experimental data is straddled by the simulation case of D intra = 0 and D intra = D inter , as expected.