Date of Award
Master of Engineering Science
Chemical and Biochemical Engineering
Dr. Sohrab Rohani
Dr. Styliani Constas
Oiling out in mixture of phenol-n-hexane was studied by experiments and molecular simulations. Oiling out encompasses the crystallization of phenol from solution of n-hexane via the formation of liquid droplets of phenol dispersed inside n-hexane that at a later stage crystallize. Oiling out was found to take place at intermediate mole fractions from Xphenoi : Xn-hexane ~ 10 : 90 to Xphenoi '■ Xn-hexane ss 30 : 70, while direct crystallization took place at other concentrations. It was also found that application of mixing diminished the size of liquid-liquid separation zone. Direct microscopic snapshots captured the formation and coalescence of liquid phenol droplets in n-hexane as well as the formation of crystals by decreasing the temperature. The liquid liquid phase separation and solid liquid separation regions for phenol-n-hexane mixture were identified using the Focused Beam Reflectance Method (FBRM) that provides valuable information about the conditions of temperature and concentration for liquid-liquid and solid-liquid phase separation. Detailed study was performed for the selection of the chord lengths of particles, which is a critical quantity in the operation of FBRM. Gas Chromatography experiments revealed the phenol distribution in mixtures of n-hexane-phenol. Direct molecular dynamics was performed in pure n-hexane, phenol and several of their mixtures at various temperatures. The simulations revealed clustering in pure phenol systems that is enhanced by lowering the temperature. Their structure and degree of solidification was characterized by radial distribution functions and clustering profiles. Diffusion coefficients and the Arrhenius activation energy were computed, that show that pure phenol and n-hexane diffuse with different rate. The simulations test the quality of force field and validate its use for large scale simulations even in the micrometer range.
Mei, Danyang, "Experiments and Molecular Simulations into the Phenomenon of Oiling Out" (2010). Digitized Theses. 3862.