Active area heating testing

In the reference case, the gas has no influence on liquid kinetics and saturation time. But we have to check this result, if the gas can escape from the chamber. In Pollock (1986), the heating of a partially saturated alluvium induces a heat-pipe effect. Liquid water vaporises near the heating source. The vapour is carried away in colder areas by means of gas darcean flux. There, vapour is liquefied. The reference case does not show any significant vaporization near the heating source, still the model we use and Pollock s one are quite similar. The non-existence of this phenomenon can not be imputed to the model. Two other explanations are then possible. It can be due to clay and alluvium behaviour differences, or to a bad evaluation of hydraulics parameters. Hence, tests have been performed to see if gas conductivity or retention curve parameters uncertainties can activate a heat-pipe phenomenon. 

Johnson Matthcy also carried out considerable work in the late 1990s on binary alloys such as Pt-Fe, Pt-Mn, Pt-Ni, Pt-Cr, Pt-Cu, and Pt-Ti [7]. For fitel cell catalysts, Pt alloys with a 50 50 Pt M ratio were heat-treated at various temperatures to improve activity. The catalyst (20 wt% Pt alloy on Vulcan carbon) was integrated into an MEA with 25 cm of active area for the fitel eell test. During fuel cell operation at 75 °C and 308/377 kPa pressure, H2 and O2 were used as the fuel and oxidant, respectively. It was found that a 20-40 mV performance... 

From the results of the urease activity test summarized in Figure 15, it is clear that the deposition procedure preserved to a certain extent the enzyme catalytic activity. Heating the sample before testing decreased the enzyme in the film by about 30% but did not eliminate it completely. The results of the activity test of two samples are summarized in Table 1 together with reference values for a spontaneous reaction without enzyme. It is necessary to underline that enzymatic activity on spherical supports was higher than the respective value in flat films, which could indicate that apparent catalytic efficiency was improved due to an increased area-to-volume ratio. 

Catalytic tests in sc CO2 were run continuously in an oil heated flow reactor (200°C, 20 MPa) with supported precious metal fixed bed catalysts on activated carbon and polysiloxane (DELOXAN ). We also investigated immobilized metal complex fixed bed catalysts supported on DELOXAN . DELOXAN is used because of its unique chemical and physical properties (e. g. high pore volume and specific surface area in combination with a meso- and macro-pore-size distribution, which is especially attractive for catalytic reactions). The effects of reaction conditions (temperature, pressure, H2 flow, CO2 flow, LHSV) and catalyst design on reaction rates and selectivites were determined. Comparative studies were performed either continuously with precious metal fixed bed catalysts in a trickle bed reactor, or discontinuously in stirred tank reactors with powdered nickel on kieselguhr or precious metal on activated carbon catalysts. Reaction products were analyzed off-line with capillary gas chromatography. 

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