Experimental Insights into the Coupling of Methane Combustion and Steam Reforming in a Catalytic Plate Reactor in Transient Mode

Abstract

The microstructured reactor concept is very promising technology to develop a compact reformer for distributed hydrogen generation. In this work, a catalytic plate reactor (CPR) is developed and investigated for the coupling of methane combustion (MC) and methane steam reforming (MSR) over Pt/Al2O3-coated microchannels in cocurrent and counter-current modes in transient experiments during start-up. A three-dimensional (3D) computational fluid dynamics (CFD) simulation shows uniform velocity and pressure distribution profiles in microchannels. For a channel velocity from 5.1 to 57.3 m/s in the combustor, the oxidation of methane is complete and self-sustainable without explosion, blow-off, or extinction; nevertheless, flashbacks are observed in counter-current mode. In the reformer, the maximum methane conversion is 84.9% in cocurrent mode, slightly higher than that of 80.2% in counter-current mode at a residence time of 33 ms, but at the cost of three times higher energy input in the combustor operating at ∼1000 °C. Nitric oxide (NO) is not identified in combustion products, but nitrous oxide (N2O) is a function of coupling mode and forms significantly in cocurrent mode. This research would be helpful to establish the start-up strategy and environmental impact of compact reformers on a small scale.

Recent Advances in the Development of Highly Conductive Structured Supports for the Intensification of Non-adiabatic Gas-Solid Catalytic Processes: The Methane Steam Reforming Case Study

“…In this view, a multiflow layout was proposed coupling the endothermic MSR with exothermic reactions, which were run in segregated adjacent channels (Chen et al, 2018). More recent applications of the same reactor concept have been reported in (Ashraf et al, 2021), where also the dynamic behavior of the system has been considered. FeCrAl was used as bulk material for the reactor (Kolb et al, 2006;Avci et al, 2010), while different active phase were evaluated for the catalytic media (Farrauto et al, 2007).…”

Shape design of channels and manifolds in a multichannel microreactor using thermal-fluid compartment models

“…Commenge et al (2002) examined the specific features of fluid flow in a microreactor with multiple channels by a simple model based on pressure drop calculations through a resistive network of ducts, which provides rapid calculation of the flow distribution. The same model was applied to recent studies, for example, the design of channel width and triangle manifold that can achieve more uniform velocity distribution (Chao et al, 2020), the design of a plate-type reformer for distributed hydrogen generation to avoid flow maldistribution (Ashraf et al, 2020), the design of a cutting microchannel plate to improve the velocity distribution (Huang et al, 2019), and the design of split-and-recombine-type flow distributors connected to microreactors (Tonomura et al, 2019a;2019b), where the ducts were referred to as the fluid compartments. While such fluid compartments are useful for predicting flow distributions, it would also be important to develop a compartment model that can predict temperature distributions, which affect reaction performance.…”