Micro membrane reactor:: a flow-through membrane for gas pre-combustion

A reactor element consisting of a permeable membrane fabricated in silicon micromachining technology will be presented. To circumvent a reaction chamber with a high dead volume, we have realised a permeable membrane in conjunction with porous silicon to achieve a high surface to volume ratio impregnated with different catalytic materials (depending on application and target gases). The complete device includes a heating element around the membrane which is thermally decoupled with a porous silicon well of the surrounding bulk material. The gas flows through the membrane and reacts during the passing time. The time of reaction for the gases depends on the membrane thickness. For optimised gas reaction, heating with an integrated temperature element is essential. The fabrication process is a combination of anisotropic silicon etch processes to create a silicon membrane with porous silicon technology to perforate the membrane. Porous silicon will also be used as thermal isolation of the active membrane and the heater. (C) 2002 Elsevier Science B.V. All rights reserved.