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Thethermodynamic consistency of almost 90 VLE data series, includingisothermal and isobaric conditions for systems of both total and partialmiscibility in the liquid phase, has been examined by means of thearea and point-to-point tests. In addition, the Gibbs energy of mixingfunction calculated from these experimental data has been inspected,with some rather surprising results: certain data sets exhibitinghigh dispersion or leading to Gibbs energy of mixing curves inconsistentwith the total or partial miscibility of the liquid phase, surprisingly,pass the tests. Several possible inconsistencies in the tests themselvesor in their application are discussed. Related to this is a very interestingand ambitious initiative that arose within the NIST organization:the development of an algorithm to assess the quality of experimentalVLE data. The present paper questions the applicability of two ofthe five tests that are combined in the algorithm. It further showsthat the deviation of the experimental VLE data from the correlationobtained by a given model, the basis of some point-to-point tests,should not be used to evaluate the quality of these data. [ABSTRACT FROM AUTHOR]

The pyrolysis of a chromium-tanned waste (bovine splitleather)under inert atmosphere has been carried out in a vertical lab scalereactor. The influence of process conditions, such as temperature,residence time, and heating rate on the pyrolytic product distributionhas been studied, in order to optimize the liquid fraction obtained.Flash pyrolysis at three different temperatures (450, 500, and 550°C) and slow pyrolysis up to 750 °C have been performed.Results indicate that, in the range of low temperatures, the productdistribution is slightly dependent on temperature. In general, a reductionof the heating rate or residence time favors the presence of heavygases (i.e., more than four carbon atoms hydrocarbons). The analysisof the pyrolytic liquid shows a wide spectrum of products (mainlynitrogenated and oxygenated compounds and phenols) which can be usefulas a source of chemicals. A comparison between the results reachedin the pyrolysis of tanned leather and a commercial collagen allowsus to study the effect of the tanning process. According to the resultobtained, the tanned leather produces more nitrogenated compoundsand phenols and less ketones and linear hydrocarbons than pure collagen.A very good agreement between the evolution of pyrolytic gases producedin a slow pyrolysis and the weight loss of the solid measured by thermogravimetricanalysis has been observed. [ABSTRACT FROM AUTHOR]