98/01180 Manufacture of town gas and its apparatus: Ota, H. and Hanawa, M. Jpn. Kokai Tokkyo Koho JP 09,202,889 [97,202,889] (Cl. C10L3/06), 5 Aug 1997, Appl. 96/11,225, 25 Jan 1996, 11 pp. (in Japanese)

Abstract

The water-gas shift reaction at low-temperature is an important chemical reaction for the manufacture of hydrogen. In view of increasing demands for hydrogen in the future hydrogen-oriented society, the CO shift converter requires a quick load response, downsized reactor dimensions, and an effective exchange of heat energy. The wall-type reactor can respond to such demands. This study investigated the CO shift performance of a copper-based catalyst, which was prepared by electroless plating consisting of zinc plating and copper plating, as a plate-type catalyst for the wall-type CO shift converter. The shift properties of the prepared catalyst varied according to metal species used in the intermediate plating prior to the copper plating. The plate-type Cu–Fe/Zn catalyst using iron for the intermediate plating presented superior shift performance. This catalyst had increased activity when oxidized prior to reaction, and was comparable or, at higher temperatures, superior to a commercial granular catalyst. Results also showed that the activity deterioration of the Cu–Fe/Zn catalyst at 250 °C was relatively low, although an ordinary copper-based catalyst suffers a high deterioration of activity during a reaction. Physicochemical measurement of the plated layer showed that it contained a large quantity of zinc derived from the displacement plating. Such zinc would move from the bulk layer to the surface layer if the catalyst drying process after plating and the pretreatment before reaction were performed in an oxidative atmosphere. The existence of zinc in proximity to copper appeared to form some reaction sites with high shift activity.