Influence of the pre-reformer in steam reforming of dodecane using a Pd alloy membrane reactor

Dodecane, one of the main components in kerosene, was used as a model material to investigate reactions in a palladium membrane reactor for steam reforming of kerosene. The influence of pre-reforming on the performance of the membrane reactor was investigated. A decrease in hydrogen yield caused by coke formation was suppressed through pre-reforming by lowering the concentration of olefins, aromatics and unreacted dodecane in the feed to the membrane reactor. In addition, the proportion of total hydrogen production that permeated the membrane was clearly higher with pre-reforming compared with that without pre-reforming. Pre-reforming prevented deactivation of both the catalyst and the membrane, resulting in efficient separation of hydrogen from the reaction field and therefore achieving a higher hydrogen yield.     

Heat transfer and pressure loss characteristics of very compact heat sinks with plate fins cooled by jets

High-performance and very compact heat sinks have been developed for effective cooling of VLSIs with high heat-generation densities. Their heat transfer and pressure loss characteristics in air-jet cooling have been experimentally studied. The highly compact heat sinks were plate-fin arrays with a very small fin pitch of 0.4–2.0 mm. The rectangular jet nozzle width that gave the highest cooling performance was 30 to 40% of the streamwise length of the heat sinks. The influence of fin height on heat transfer became weak when the ratio of the height to the thickness of the fin exceeded approximately 35. When the air flow rate was constant, the thermal conductance increased as the fin pitch decreased. For a constant fin pitch, heat sinks with smaller fin thickness showed larger thermal conductance at a given blower power consumption. In our experimental range, the heat dissipation rate per unit heat sink volume increased as the base plate area of the heat sink became small. © 1998 Scripta Technica, Heat Trans Jpn Res, 27(6): 399–414, 1998