Traditional Stacks

The cooling system is combined with the electrolyte loop. Hence there is no need for a separate cooling system such as in the PEFC. However, the direct contact between the electrolyte and the gas chambers allows the water (the reaction product) to dilute the electrolyte. Therefore, to prevent a low ion conductivity of the electrolyte, re-concentration of the electrolyte is necessary to maintain a constant KOH concentration (because the conductivity is decreased by increasing the water flow to the electrolyte). 

---

There have already been a number of excellent reviews describing many aspects of SOFC, and we will not try to duplicate that literature. For information on stack designs and cells operating on H2 or on synthesis gas (a mixture or H2 and CO) produced by reforming, we refer the reader to those other reviews. In this review, we will focus on recent work aimed at operating SOFC directly on hydrocarbon fuels and on anode materials that are compatible with direct hydrocarbon utilization. We have further restricted the scope to the performance and analysis of single-cell systems. While stacks that operate directly on hydrocarbons will likely need to be different from more traditional stacks, the development of direct-utilization SOFC is still in its infancy, with only one report of preliminary data on the stack level. 2 ... 

Domestic and commercial furniture and fittings form another important market. Uses include stacking chairs, armchair body shells, foam upholstery and desk and cupboard drawers, whilst chipboard and decorative laminates are very widely used. The variety of finishes possible at a relatively low cost compared to traditional materials as well as ease of maintenance are important in raising standards of living around the world. As with other applications the use of plastics in furniture is not without its detractors and in particular there is concern... 

An alternative simple model for contaminant dilution of rooftop exhaust stacks is presented in Halitsky. This model combines a jet region specification for the upward exhaust movement with a more traditional Gaussian plume region controlled by atmospheric and building-generated turbulent dilution. 

Both effects are demonstrated by the traditional smokestack release shown in Figure 5-15. The material released from the smokestack contains momentum, based on its upward velocity within the stack pipe, and it is also buoyant, because its temperature is higher than the ambient temperature. Thus the material continues to rise after its release from the stack. The upward rise is slowed and eventually stopped as the released material cools and the momentum is dissipated. 

Water on Smectites. Compared to vermiculites, smectites present a more difficult experimental system because of the lack of stacking order of the layers. For these materials, the traditional technique of X-ray diffraction, either using the Bragg or non-Bragg intensities, is of little use. Spectroscopic techniques, especially nuclear magnetic resonance and infrared, as well as neutron and X-ray scattering have provided detailed information about the position of the water molecules, the dynamics of the water molecule motions, and the coordination about the interlayer cations. 

The design of BP for PEMFCs is dependent on the cell architecture, on the fuel to be used, and on the method of stack cooling (e.g., water or air-cooling). To date, most of the fuel cells have employed traditional filter-press architecture, so that the cells are planar and reactant flow distribution to the cells is provided by the bipolar plate. The bipolar plate therefore incorporates reactant channels machined or etched into the surface. These supply the fuel and oxidant and also provide... 

---