Engineers faced with a crystallization problem are likely to seek data on the solubilities of the substances involved. However, solid-fluid equilibrium (SFE) phase diagrams offer advantages that cannot be gained from solubility data alone. This article provides a detailed discussion of how to best use SFE phase diagrams, particularly for multicomponent mixtures.

Most engineers are familiar and comfortable with equations that correlate data. But all would be well-advised to remember that every correlation has its limitations. During a calculation, the flame temperatures of several gases were found to be suspect beyond the range of the heat-capacity correlations used in the calculations. Take a journey with this author, as he routes out the mathematical discrepancies and stakes out an alternate route to solving the original problem.

A host of field-screening methodologies including immunoassay and turbidimetric techniques, field-hardened infrared spectroscopy and gas chromatography, and the use of organic vapor analyzers are readily available to help engineers characterize petroleum-based releases during site remediation. This article discusses the pros and cons of each. Screening tools speed site clanup.