(638a) Analysis of (side) Product Inhibition in the Measurement of Reaction Rates in Packed-Bed Flow Reactors: The Case of Ethane Partial Oxidation
AIChE Annual Meeting
Thursday, November 11, 2021 - 3:30pm to 3:48pm
Using ethane oxidation over bulk nickel oxide as an example, we show how product co-feeds can be used to gain insights into reaction kinetics that are then used to analyze integral bed data obtained in the absence of product co-feeds. Rates are a very strong function of conversion, with partial oxidation rates decreasing by up to 50% between 0.2-2% ethane conversion. Although lowering the ethane conversion narrows the gap between measured and true rates, it leads to an amplification of normalized rate gradients that make rate estimation harder at lower rather than higher conversions. Partial oxidation rate data over pure nickel oxide, unlike those over niobium-doped nickel oxide, can only be explained when the effect of both CO2 and water on measured rates are considered- observations that are rationalized within a framework of carbonate mediated product inhibition that decreases in relative preponderance with increasing niobium loadings. Our study provides a mathematical foundation for analyzing product inhibition for non-power law rate expressions and extends this analysis to cases where side products also inhibit reaction rates.