Joseph D. Henry

Particle transfer from a continuous oil to a dispersed water phase: model particle study

The surface free energy of glass microbeads was controlled by varying the extent of reaction between t-butyldimethylchlorosilane with the surface silanols. This system was chosen so that the surface free energy of the particles could be varied without introducing an extraneous wetting agent. The wicking method was used to obtain the liquid-particle-air contact angles. Water-air contact angles on glass beads increased with increasing silanizing reaction. The dispersive and the nondispersive contributions of the surface free energy were calculated from the contact-angle data. Nondispersive contribution decreased with increasing silanizing reaction while dispersive component remained unchanged. These silanized glass beads were dispersed in the continuous oil phase and the extent of particle retention at the water-oil interface and distribution to the water phase were determined. The experimental data indicate that the surface free energy of particles is the controlling parameter determining the transfer of particles from the oil phase to the water phase. Particle size in the range 5–20 μm had no significant effect, either on the particles retained or distributed to the water droplets.

Novel Separation Processes for Solid/Liquid Separations in Coal Derived Liquids

Abstract The removal of the mineral matter found in coal derived liquids is a very difficult solid/liquid separation process. Clays, pyrites and other minerals that occur in coal ultimately find their way into the liquefied product. This is the case, e.g., for both the solvent refined coal (SRC-I) and H-Coal processes. The ash content of bituminous coals which may be fed to coal liquefaction processes normally rangesfrom 6 to 11 wt.%. The ash content of the coal liquid product can range from 4 to 20 wt.% depending upon the lique-faction .process. Ash levels must be reduced to, e.g., 0.4 wt.% in the case of boiler fuel and less than 0.1 wt.% for gas turbine fuels.

Mechanisms of particle transfer from a continuous oil to a dispersed water phase

Abstract The kinetics of particle transfer from a continuous to a dispersed liquid phase has a major effect on the performance of solid/liquid separation processes which use a dispersed liquid phase as a mass separating agent. Previous studies have been inconclusive because of the competing effect of surfactant transfer kinetics which can produce a time-dependent three-phase contact angle. Model glass particles with well defined wetting characteristics which were obtained by chemisorbed silanizing agents were utilized in this investigation. The three-phase contact angle was constant because additional surfactant wetting agents were not employed. The experimental investigation indicated that the three-phase contact angle, mixing speed, and initial particle concentration in the oil phase were primary parameters which affect both the rate and extent of particle transfer from a continuous oil phase to a dispersed water phase. A kinetic model was developed which considers the hydrodynamics of film rupture as a dispersed water droplet approaches a particle. The model includes the induction time for the rupture of the oil film during the encounter between water and particles and the induction time for the rupture of a water film when particles are transferred back from the dispersed water phase to the continuous oil phase. particles are transferred back from the dispersed water phase to the continuous oil phase.