Development of simple-to-use predictive tool for rapid prediction of n-alkanes surface tension

One of the most striking demonstrations of intermolecular forces is the tension at the surface of liquid n-alkanes. The prediction of surface tension is important in the design of distillation towers, extraction units, and tower internals such as bubble caps and trays because it has a considerable influence on the transfer of mass and energy across interfaces. Surface-tension data are needed wherever foaming emulsification, droplet formation, or wetting are involved. They are also required in a number of equations for two-phase-flow calculations and for determining the flow regime. Petroleum engineers are especially interested in the surface tension in the extraction of crude oil where adding surfactants to modify the interfacial properties between crude oil and the geological reservoir can improve production and increase oil yields. In this work, a simple predictive tool using Arrhenius-type asymptotic exponential function, the Vandermonde matrix, and Matlab (Matlab 2008) technical computing language is developed for the estimation of surface tension of paraffin hydrocarbons as a function of molecular weight and temperature. The surface tension is calculated for temperatures in the range of 250 to 440 K and paraffin hydrocarbon molecular weights between 30 and 250. The proposed numerical technique is superior owing to its accuracy and clear numerical background, wherein the relevant coefficients can be retuned quickly if more data become available in the future. Estimations are found to be in excellent agreement with the reliable data in the literature, with average absolute deviation being less than 2%.