(122b) Streamlining the Single Event Kinetics Based Simulation of a Catalytic Naphtha Reformer

Authors: 
Martinis, J., Bryan Research & Engineering Inc
Froment, G. F., Texas A&M University


A 19 KBPD commercial Catalytic Reforming Unit using a 4-bed stacked reactor for the production of BTX has been simulated. The underlying chemistry of Catalytic Reforming on noble metal-loaded acid catalysts is modeled by means of a computer-generated reaction network consisting of 50,000+ elementary steps and containing 4,700 species within the C1 - C10 carbon range. The Single-Event Kinetics approach allows the reduction in the number of independent kinetic parameters to 44. Material and Energy conservation equations are applied to formulate a model for the radial flow of species in a packed-bed adiabatic reactor. The resulting model also accounts for pore diffusion limitations and catalyst deactivation by coke formation. Equilibration of fast elementary steps such as alkene (de)protonations and methyl-/Ethyl- shifts lead to a reduction in the number of non-intermediate species from 326 pure species to 68 groups of isomeric species in equilibrium, making the resulting number of compound species suitable for process simulation purposes. Molecular reconstruction of naphtha cuts by group contributions from typical operational follow-up data such as specific gravity, C/H elemental analysis and GC simulated distillation is applied to predict the most likely composition of the feedstock. By their very essence, the Single-Event Kinetic parameters are invariant from the naphtha composition. This enabled a series of simulations for different blends from a pool of 62 naphtha cuts aiming to maximum Hydrogen and BTX production.