Influence of tubular reactor structure and operating conditions on dry reforming of methane

Abstract

This paper investigates the influence of reactor structure and operating conditions on dry reforming of methane (DRM), using a two-dimensional reactor model. Two tubular reactors commonly used in the industry are included: one is a mono-tube reactor, the other contains a concentric heating tube. The reactor structure and operating conditions significantly affect temperature distribution and methane conversion in the two reactors. Catalyst dilution in catalyst beds is efficient to control temperature but also largely decreases methane conversion, indicating a balanced packing density of catalyst is required. Reducing the tube radius is useful to control temperature and can save a lot of (in some cases >90%) catalyst, which demonstrates the great potential of using tubular reactors with a small radius. The inlet temperature only slightly changes temperature distribution and methane conversion. The elevated total pressure reduces temperature gradient and also methane conversion, while the feed CH4/CO2 ratio only importantly affects the equilibrium conversion of methane. Comparing temperature distributions and methane conversions in the two reactors, the tubular reactor with a concentric heating tube performs better and uses 11–67% less catalyst. These results should serve to guide the design of tubular reactors for DRM and other highly endothermic reactions.