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The Biomass Program develops design cases to understand the current state of conversion technologies and to determine where improvements need to take place in the future. This design case establishes cost targets for converting MSW to ethanol and other mixed alcohols via gasification.

The influence of low concentration levels of calcium and magnesium ions present in the cell feed on the performance of a laboratory membrane-type chlor-alkali electrolysis cell was determined experimentally. Identification and location of the precipitates were obtained by evaluation of the degraded membranes by scanning electron microscopy (SEM) and electron probe x-ray microanalysis (EPMA) after experimental determination of cell potential and current efficiency for various feed brine purities

Probably the most useful diagnostic for high voltage insulation is a measurement of partial discharge (PD) activity. Even for insulation systems which are designed to be discharge free (such as polymeric cables, enclosed busbars etc), where PD activity is nevertheless present, and hence potentially responsible for insulation deterioration, measurements of PD activity are vital to avoid plant failure. As the PD voltages tend to be small, other electromagnetic interfering signals are always a problem. In addition, there may be many PD sources in a power network, all contributing to the overall measured pulses. The separation and localisation of the PD activity is still a major task in improving the quality of the measured PD data.

Modele mathematique d'un systeme comprenant un reacteur electrochimique a plaques paralleles et un reacteur continu agite, avec recyclage total ou partiel, utilise pour predire le comportement au cours du temps de l'obtention de cuivre a partir d'une solution aqueuse de HCl. Ce modele comprend plusieurs aspects negliges auparavant: la cinetique des reactions a l'electrode, la condition de neutralite electrique, trois processus de transfert de matiere des ions dans l'electrolyte (diffusion, migration ionique, convection), l'ecart des electrodes dans le reacteur electrochimique et l'inclusion d'un veritable reacteur continu agite dans le courant de reglage

An extensive survey of the Docktor‐Ingenieur Dissertationen of Jakob Jorissen and Klaus‐R. Menschig, both originally from the Universitat Dortmund, is presented in regard to the empirical modeling of membrane chlor‐alkali cells and how it can be applied to a combined zero gap/attached porous electrode layer membrane cell. Particular emphasis is placed on Menschig's work on zero gap (ZG) and attached porous electrode layer (APEL) membrane chlor‐alkali cells, the first such research to appear in the open literature. Menschig developed various computer programs to characterize these ZG and APEL membrane chlor‐alkali cells. He characterized these cells by using the following parameters: the current density distribution over the membrane, the species concentrations on the membrane surfaces, equivalent diffusion layer thicknesses for the mesh electrodes/current collectors and attached porous electrode layers, and the electrode overpotentials and equilibrium potentials using the surface concentrations for the ZG and APEL cell configurations. He used empirical equations first presented by Jorissen for gap membrane cells combined with his own experimental observations for a cell which used Nafion™ 390, a bilayer perfluorosulfonic acid membrane, to determine values for these parameters. His empirical relations describe the dependence of the flux of OH− from catholyte to anolyte as a function of catholyte caustic concentration and the membrane potential drop as a function of catholyte caustic and anolyte salt concentrations. By using the experimental values for total cell potential, current density, and cell outlet concentrations with the empirical equations, Menschig calculated values for the characterizing parameters mentioned above. He used these values and other information (e.g., membrane and porous electrode layer conductivity) to predict the total cell potential for the ZG configuration. With prior knowledge of total cell potential and current efficiency for corresponding APEL and ZG cell configurations, membrane surface concentrations were derived and used in the prediction of total cell potential for a combined zero gap/attached electrode cell.

Cette methode consiste a formuler les equations gouvernantes et a resoudre par integration numerique une serie d'equations a plusieurs dimensions, couplees, non lineaires, dependant du temps

On presente un calcul de bilan matiere, en vue de tester la compatibilite d'un modele de reacteur electrochimique a plaques paralleles publie precedemment. Utilisation de nouvelles expressions pour calculer la concentration moyenne des especes et la densite de courant moyenne de la reaction j, a partir de la concentration et des distributions de potentiel predites. Simplification des equations du modele precedent, en supposant que le gradient de concentration axiale de l'espece i peut etre approche par un changement en echelons de la concentration connue de l'alimentation a la concentration inconnue de la sortie

A theoretical model is presented for a Teflon-bonded carbon porous diffusion electrode used for oxygen reduction in alkaline solution. The model is of the flooded agglomerate type and is extended to allow parameter estimation by regression analysis of polarization data. The data presented are for a Teflon-bonded carbon electrode (silver catalyst) tested in a laboratory scale cell using 3.5M (150 kg/m3) sodium hydroxide solution at 348 K with three different oxygen feed mole percents: 10, 20, and 100%. Regression indicates that the diffusion processes in both gas and liquid phases contribute significantly to polarization.

A method is presented for predicting shunt currents in stacks of undivided and divided bipolar plate cells. The method is an efficient way of solving the coupled sets of algebraic equations that arise from using circuit analog models to represent the current paths in stacks of undivided or divided bipolar plate cells. These algebraic equations can be either linear or nonlinear depending upon the current-potential relationships used in the model (i.e., nonlinear circuit elements can be included). The method is used to show the importance of including nonsymmetrical resistances and nonlinear circuit elements in the models. Also, the method is used to predict the shunt currents for a nine cell stack of pilot plant scale bipolar plate, membrane chlor-alkali cells. It is shown that these predictions agree qualitatively with measured values. Finally, the method is used to predict the shunt currents for stacks of 60 and 120 of these cells.

Correlations producing thermodynamic property tables employ the concepts of scaling with increasing frequency in the vapor-liquid critical region. One of the important concepts is that the vapor pressure equation should provide infinite curvature and finite slope ψc at the critical point. The vapor pressure critical exponent θ describes the divergent curvature in a power law expression. This paper provides an extensive study of θ. We have determined an optimal value of θ by two general approaches: a curve fit method (CFM) which employs least-squares analyses, and a numerical derivative method (NDM). The CFM is interpolative but requires a vapor pressure equation, while the NDM is extrapolative but is independent of the vapor pressure equation. The vapor pressure equations, which satisfy scaling concepts most closely, exhibit a very flat minima for the CFM. As a result, the values of θ which provide reasonable correlations vary over an appreciable range (depending upon the compound, form of the equation, and the temperature range). The NDM did not present any particular difficulties. Our overall weighted average for θ is 0.199 with a standard deviation of 0.052, while the overall numerical average was 0.225 with a standard deviation of 0.045; the final recommended value of θ is 0.22 ± 0.04.