Sub-Micron Particle Removal From Gas-Water Mixtures Without Flow Restrictions

The removal of sub-micron sized particles from an aqueous stream based on electrostatic attraction is proposed. The system will remove suspended particles from a gas-water-solid mixture with minimal flow restrictions. This is particularly important for the removal of fine alumina particles in the outlet stream from the Volatile Removal Assembly (VRA), since high pressures are required to force the gas-water mixture through a small pore collection filter. Electrophoretic particle removal will result in direct capture on the oppositely charged surface of removal media or an electrode, or by collection of larger aggregates formed at such surfaces on a large pore filter. Zeta potential is a measure of the effective surface charge on suspended particles. For oxides, the zeta potential varies strongly with pH, reaching zero at the isoelectric pH. The zeta potential is negative at pHs above this value, and positive at pHs below it. Particle collection by removal media requires an opposite polarity zeta potential, or alternatively, an electrode with the proper surface potential at the pH of interest. The Phase I effort will demonstrate feasibility. The Phase II project will result in the delivery of a prototype scaled to handle the nominal VRA flow rates.