Development of a stand-alone steam methane reformer for on-site hydrogen production

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>A small, stationary reformer designed as a stand-alone and self-sustaining type was developed for on-site hydrogen (H<SUB>2</SUB>) production. We created a compact reformer to produce H<SUB>2</SUB> at a rate of 1 Nm<SUP>3</SUP>/h using the previously reported reaction kinetics of steam methane reforming (SMR). Both catalysts for the compact reformer - i.e., 15 wt% and 20 wt% Ni/γ-Al<SUB>2</SUB>O<SUB>3</SUB> - showed good activity, with CH<SUB>4</SUB> conversion exceeding 90% at 655 °C and a contact time of 3.0 g<SUB>cat</SUB>h/mol, which were considered critical thresholds in the development of a small, compact stationary reformer. At an H<SUB>2</SUB> production rate of 1 Nm<SUP>3</SUP>/h, the catalyst amount was calculated to be 167.8 g and the reformer length required to charge the catalyst was 613 mm, with a diameter of 1 inch. The CH<SUB>4</SUB> conversion and H<SUB>2</SUB> production rates achieved with the compact reformer using the 20 wt% Ni/γ-Al<SUB>2</SUB>O<SUB>3</SUB> catalyst at 738 °C were 97.9% and 1.22 Nm<SUP>3</SUP>/h, respectively. Furthermore, a heat-exchanger type reformer was developed to efficiently carry out the highly endothermic SMR reaction for on-site H<SUB>2</SUB> production. This reformer comprised a tube side (in which the catalysts were charged and the SMR reaction took place by feeding the reactants) and a shell side (in which the heat for the endothermic reaction was supplied by CH<SUB>4</SUB> combustion). Reforming activities were evaluated using the active 20 wt% Ni/γ-Al<SUB>2</SUB>O<SUB>3</SUB> catalyst, depending on the reactants' gas hourly space velocity (GHSV). The H<SUB>2</SUB> production rate increased as the GHSV increased. Finally, the reformer produced a CH<SUB>4</SUB> conversion of 98.0% and an H<SUB>2</SUB> production rate of 1.97 Nm<SUP>3</SUP>/h at 745 °C, as well as a high reactants' GHSV of 10,000 h<SUP>−1</SUP>. Therefore, the heat-exchanger type reformer proved to be an effective system for conducting the highly endothermic SMR reaction with a high reactants' GHSV to yield a high rate of H<SUB>2</SUB> production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Development of the compact reformer for 1 Nm<SUP>3</SUP>/h production rate. </LI> <LI> The heat-exchanger type reformer with CH<SUB>4</SUB> combustion as a stand-alone and self-sustaining type for on-site H<SUB>2</SUB> production. </LI> <LI> 99.7% CH<SUB>4</SUB> conversion and 1.21 Nm<SUP>3</SUP>/h H<SUB>2</SUB> production rate obtained by the heat-exchanger type reformer at 798 °C. </LI> <LI> The H<SUB>2</SUB> production rate was increased with increasing the reactants' GHSV. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>