Non-uniformity among multi microchannels for Fischer-Tropsch synthesis

Non-uniformity in flow rates, channel dimensions and catalyst loading among multi microchannels commonly arises during design, manufacturing, operation and measurement. Quantifying the tolerance thresholds of such non-uniformities is therefore of practical importance. In this paper, the complex interplay among flow maldistribution, channel dimensional variation, and catalyst loading heterogeneity is elucidated by distinguishing between packed-bed, washcoated, and thin-film microchannels. Mathematical approaches are developed to investigate the effects of non-uniformity among microchannels on residence time distribution (RTD), reaction performance, product selectivity, catalyst deactivation and thermal management under both isothermal and non-isothermal conditions. Results suggest that the effects of non-uniformity, particularly in flow rates, on Fischer-Tropsch synthesis (FTS) performance and catalyst lifetime are limited due to intrinsic performance compensation among channels. However, under insufficient temperature control, deviations in reaction performance are dominated by heat release and the resulting temperature rise, rather than solely flow maldistribution. Furthermore, non-uniformity in catalyst loading can significantly increase the risk of thermal runaway in the microchannel reactor system. The results highlight that the pursuit of perfectly uniform channel-to-channel distribution may be less critical than commonly assumed, whereas achieving and maintaining near-isothermal operation is of primary importance for safe and stable reactor performance.