Effectiveness factor under cyclic operation of a reactor

Results are reported on the influence of intraparticle diffusion on the measured rate of reaction under a condition where the feed composition is changing periodically. The specific application is to cyclic operation of an ammonia synthesis reactor. The effectiveness factor calculated relative to the steady‐state kinetic rates for the time‐average feed condition for fine particles was higher than the comparable steady‐state effectiveness factor as a result of the rate improvement due to cycling. The effectiveness factor calculated relative to the time‐average rate of reaction under cyclic operation for the fine particles was much less than unity and similar numerically to the steady‐state effectiveness factor. The cycling effectiveness factor by either definition varied with cycling conditions because of the complex interaction of cycling parameters.