(629ap) The Effect of Zn-Ni-Ferrite Catalyst for HTS Under LNG Reformate Condition
The hydrogen fuel cell systems have been developed for the sustainable technology and the steam methane reforming (SMR) is widely operated to produce the high purity gaseous hydrogen. However, there is approximately 10% of carbon monoxide gas in reformate and the remained CO gas poison the Pt electrodes in the polymer electrolyte membrane fuel cell (PEMFC) system. Therefore, the water gas shift reaction (WGSR) has been applied for removing the CO gas in the large-scale plants.
The WGSR has been generally operated by the combination of the two series reaction: a low-temperature shift (LTS, operating at 190-250°C) and a high-temperature shift (HTS, operating at 350-450°C) to increase the heat efficiency and to achieve the effective CO conversion. The conventional Fe-Cr-Cu catalyst for HTS, however, has a serious problem which is that the level of about 1 wt% hexavalent chromium (Cr6+) remains into the commercial catalyst and this heavy metal ion very toxic to humans and other organisms.
For the above reasons, there is a growing need for the alternative HTS catalyst such as Cr-free Fe based metal oxide. In previous study, we found that the Ni-ferrite showed the significant WGSR performance. In this study, the Ni-ferrite catalyst was promoted by adding Zn to restrain methanation and increase WGSR activity.