MODELING OF PULSED GAS-TRANSPORT EFFECTS IN THE TAP REACTOR SYSTEM

A method for quantification of the gas pulse transport in the TAP (tem poral analysis of products) reactor system is presented. Particular co mponents of the TAP reactor system that are considered include the hig h-speed pulse valve, the packed-bed microreactor, and the high vacuum system. The model developed for the pulse valve allows an a priori eva luation of the inlet pulse intensity as a function of feed gas conditi ons and valve settings. Two independent models that account for simult aneous diffusion, adsorption, and desorption are developed for the pac ked-bed microreactor. The first model describes the transient response of the microreactor packed with nonporous particles and is primarily intended for assessment of gas pulse transport in the interparticle re gion and on the particle surface. The second model is similar, except that it accounts for diffusion of the gas pulse in porous particles. M olecular beam transport and an evaluation of backscattering in the vac uum system behind the microreactor are also quantified. Evaluation of model parameters by a time-domain parameter estimation technique is al so described and illustrated through several applications including es timation of diffusivities and desorption parameters. The modeling appr oach presented here forms a basis for further quantification of TAP st udies. (C) 1994 Academic Press, Inc.