Abstract
New regulations in 1991 (HMβ183) have required that materials may not be coshipped in the same cargo tank motor vehicle if, as a result of their mixing ββ¦an unsafe condition would occur, such as an explosion, fire, excessive increase of pressure or heat or the release of toxic vapors.β
In order to determine the potential hazards resulting from inadvertent mixing which would result in a hazardous condition, a technically sound evaluation procedure was needed which was reasonably accurate as well as time and cost effective. This required both thermodynamic (heat and/or pressure released) and kinetic parameters (is the energy released immediately or does it take a day, week, month etc.?). A model has been developed using the SimuSolvA Trademark of the Dow Chemical Co.
computer program and Microsoft's EXCELβ’ spreadsheet which combines the kinetics and thermodynamics for a reaction with the heat transfer parameters for a given tanker truck. Real heat loss data were then obtained for a typical compartmentalized tanker truck for use in the model. The rates and enthalpies for reaction input can be taken from ARC, DSC, or literature data. Since a very large number of binary combinations of potentiai mixtures are possible, materials were grouped according to chemical functionality. A model compound was chosen to represent each functional group. These materials were chosen to best represent the worstβcase reactivity of the group, unimpeded by steric or other factors. A single material/formulation could be classified into more than one grouping. Representative data were complied from experimental studies (Mixing calorimetry, ARC, DSC, etc.) and a wide variety of internal and external literature sources. Where outside sources described a potential incompatibility between groups, the data were gathered on model compounds and input into the model to determine pertinent compatibility. A compatibility chart was constructed for the resulting potential binary mixtures based upon these results.