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Hiratsuka, Japan

Nikki Universal Co and Hitachi - GE Nuclear Energy | Date: 2011-04-27

A recombination apparatus is provided to an off-gas system of a boiling water nuclear plant. An off-gas system pipe connected to a condenser is connected to the recombination apparatus. A catalyst layer filled with a catalyst for recombining hydrogen and oxygen is disposed in the recombination apparatus. The recombination catalyst has a percentage of the number of Pt particles whose diameters are in a range from more than 1 nm to not more than 3 nm to the numbers of Pt particles whose diameters are in a range from more than 0 nm to not more than 20 nm, falling within a range from 20 to 100%. The condenser discharges gas containing an organosilicon compound (ex. D5), hydrogen, and oxygen, which is introduced to the recombination apparatus. Use of the above recombination catalyst can improve the performance of recombining hydrogen and oxygen more than conventional catalysts and the initial performance of the catalyst can be maintained for a longer period of time.

A catalyst composition of excellent silicon-resistant performance, and a catalyst containing the catalyst composition are provided. The catalyst composition is one for purifying an exhaust gas containing an organic compound, the catalyst composition comprising at least one inorganic oxide (component 1) selected from the group consisting of alumina, zirconia, titania, silica, ceria, and ceria-zirconia, each having a noble metal supported thereon; zeolite (component 2) having supported thereon at least one metal selected from the group consisting of Fe, Cu, Co and Ni; and a PtFe composite oxide (component 3).

Tada S.,University of Tokyo | Tada S.,Japan Society for the Promotion of Science | Minori D.,University of Tokyo | Otsuka F.,University of Tokyo | And 4 more authors.
Fuel | Year: 2014

The removal of CO from hydrogen-rich gas produced by steam reforming of hydrocarbons by selective CO methanation was investigated over xwt%Ru-ywt%Ni/TiO2 (x = 0, 0.2, 0.3, 0.4, y = 0, 5, 9). The bimetallic catalyst Ru-Ni/TiO2 exhibited higher activity of CO methanation at low temperatures and lower activity of CO2 methanation at high temperatures than Ru/TiO2. Especially, 0.2 wt%Ru-9 wt%Ni/TiO2 was the most suitable catalyst for selective CO methanation. As for the prepared Ru-Ni/TiO2 catalysts, the reverse water gas shift (RWGS) reaction was accelerated with an increase in the Ru loadings. Consequently the 0.2 wt%Ru-9 wt%Ni/TiO2 produced little CO due to the low activity of RWGS reaction, resulting in rapid abatement of CO at low temperatures and low production of CH4 at high temperatures compared to 0.3 wt%Ru-9 wt%Ni/TiO2 and 0.4 wt%Ru-9 wt%Ni/TiO 2. © 2014 Elsevier Ltd. All rights reserved.

Tada S.,University of Tokyo | Tada S.,Japan Society for the Promotion of Science | Kikuchi R.,University of Tokyo | Wada K.,Toshiba Corporation | And 4 more authors.
Journal of Power Sources | Year: 2014

Selective CO methanation was carried out over 10 wt%Ni/TiO2 and 0.5 wt%Ru-10 wt%Ni/TiO2, and the durability was examined. During the long-term test, both catalysts abated CO concentration from 0.25% (dry base) to less than 0.05% above ca. 175 °C with CO2 methanation suppressed. Ru-Ni/TiO2 exhibited the high activity of CO methanation compared to Ni/TiO2 during the test. Furthermore, for more than 5500 h, Ru-Ni/TiO2 maintained a wide temperature window for selective CO methanation (>50 °C), where CO and CH4 concentrations were <0.05% and <1%, respectively, at a high gas hourly space velocity of 10,000 h-1. Over Ni/TiO2 and Ru-Ni/TiO2, CO2 methanation activity was initially enhanced, and then stabilized. The initial promotion of CO2 methanation activity is possibly due to the reduction of NiO which remained unreduced after the prereduction by H 2 at 450 °C. © 2014 Elsevier B.V. All rights reserved.

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