Study of the Effect of Porous Particles on Vapor-Liquid Equilibrium Using the Headspace Gas Chromatography

The effect of certain porous particles on vapor-liquid equilibrium (VLE) of ethanol + water, ethanol + ethyl acetate, acetic acid + ethyl acetate, and n-hexane + n-heptane systems was investigated using the headspace gas chromatography (HSGC) at 60, 50, 50, and 50 degrees C, respectively. Four kinds of porous particles were studied: molecular sieves (3 angstrom, 4 angstrom, 5 angstrom, and 13 X), activated carbons (columnar activated carbon, powdered activated carbon), activated alumina balls, and nonpolar adsorption resins (D4006, D4020). Good agreement was noticed when the experimental results in the absence of porous particles were compared with the NRTL model's predictions. These results added to the validity of using the HSGC in studying the VLE of binary systems. The results obtained showed that the VLE of these four kinds of binary mixtures in the presence of molecular sieves and activated alumina balls was altered considerably. The presence of activated carbons had no effect on the VLE of these binary systems, but the VLE of n-hexane + n-heptane system was altered in the presence of D4006 or D4020 nonpolar adsorption resin. Other factors, such as pore size, type, weight, properties of porous particles, and solvents were also investigated. The results showed that the alteration in the VLE of a given binary solution was a function of the pore size, type, weight, properties of porous particles and the properties of solvents. In addition, the mechanism of the porous particles altering the VLE was also analyzed accordingly. (C) 2015 American Institute of Chemical Engineers