Radial MicroChannel Reactors (RMR) Enable High Efficiency and Low Cost MSR

摘要

The transition to a hydrogen fuel economy requires the efficient conversion of the existing natural gas distribution network for providing hydrogen suitable for use by PEM fuel cells. This in turn requires low-cost, high efficiency and safe technologies capable of converting natural gas to hydrogen at the pump and eventually at home. This paper presents a "Radial MicroChannel Reactor" (RMR) architecture for manufacturing highly compact steam reformers capable of achieving overall power densities comparable to existing autothermal reformers (ATRs) at reduced catalyst loadings and high space velocities resulting in dramatic reduction of the system size and the weight [1]. The RMR system is manufactured via laser welding techniques originally developed for constructing highly compact gas purification systems. Each microchannel is formed from the annular gap between two nested small tubes, typically designed to have a gap width between 300 and 700 microns. The outer tube is closed at one end and welded into manifold 'A' at its other end. The inner tube has one end, close to the closed end of the outer tube and other end welded to manifold 'B'. More than 1,000 such individual RMR assemblies may be integrated in parallel using a close packed hexagonal pattern in an 8" diameter manifold. This network of RMR assemblies is suspended in a single combustion volume suitable for atmospheric ignition of fuel and air during startup while enabling a smooth transition to catalytic combustion at the outer tube surfaces at steady-state. Catalytic combustion on the outer surface of each RMR provides efficient transfer of combustion heat to the reforming reaction on the inner surface of the outer tube.