Fuel utilization effect

Fuel utilization effect on ceU polarization in presence of CO, calculated for 1 atm, 75% (top) or 40% (bottom) inlet, with 10 ppm CO. In each case, the polarization curve is calculated for four fuel utilization levels of 0, 0.5,0.8 and 0.9. (From Springer, T. et al, 2001. Journal of the Electrochemical Society, 148 A11-A23. With permission.)... 

Fig. 10.8 Fuel utilization effect on micro-tubular cell performance...

Nevertheless, as already discussed in respect of the Fuel Utilization effect, at reduced temperature the ohmic drop due to lower cell conductivity becomes predominant on the other effects driven by N2 dilution. 

Kerosene can be utilized effectively to reduce the pour point of most distillate fuels. The dilution limits are often based upon whether kerosene dilution will negatively impact fuel properties such as the viscosity, distillation parameters, sulfur limit, or cetane number. 

Under the ribs, the species diffusion in the direction orthogonal to the cell plane, i.e. cross-plane diffusion, is obviously impossible. Hence, the reactant concentrations on the electrode/electrolyte site under the ribs are driven only by in-plane diffusion. Due to the strong diffusion property of H2, in-plane diffusion allows H2 to penetrate under the ribs, while in the case of O2, a relevant concentration reduction is noticed. The effect of the ribs is significant at all operating conditions, but it becomes predominant at high fuel utilization (not shown in the figures). 

Department of Chemistry and Chemical Engineering and Center for Health Effects of Fossil Fuel Utilization, Massachusetts Institute of Technology,... 

Springer, T.E. et al.. Model for polymer electrolyte fuel cell operation on reformate feed effects of CO, H2 dilution, and high fuel utilization, J. Electrochem. Soc., 148, All, 2001. 

The actions of epinephrine and norepinephrine in the liver, the adipocyte, the skeletal muscle cell, and the a and 3 cells of the pancreas direcdy influence fuel metabolism (Fig. 43.6). These catecholamines are counterregulatory hormones that have metabolic effects directed toward mobilization of fuels from their storage sites for oxidation by cells to meet the increased energy requirements of acute and chronic stress. They simultaneously suppress insulin secretion, which ensures that fuel fluxes will continue in the direction of fuel utilization rather than storage as long as the stressful stimulus persists. 

Fig. 1.99 Effect of methanol concentration (1.0 M and 2.0 M Methanol) upon the performance of a direct methanol fuel utilizing a PSSA-PVDF membrane at 60 °C (12 L min." and 20 psig oxygen).

Problematic crossover effects can be minimized by strategic cell design, provided that inter-diffusion is restricted to a small interfacial width at the center channel, from which anode and cathode are adequately separated. However, the location and dimensions of the electrodes may also influence fuel utilization and overall cell resistance. 

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