GB1358695A - Dielectrophoretic separation process and apparatus - Google Patents

Abstract

1358695 Electrostatic separation ESSO RESEARCH & ENG CO 5 Aug 1971 [5 Aug 1970] 37807/70 Heading B2J [Also in Division C5] Dissolved and/or dispersed wax, resin and asphaltic material are separated from a petroleum feedstock by subjecting it to a non- uniform electric field, the intensity of which is greatest at one of two electrodes whereby the separated material concentrates or deposits therearound. Said one electrode may comprise fixed rods or wires or discrete particles of immiscible liquid or solid which differ in specific gravity from the feedstock. Such particles are charged before use and may be recycled after cleaning. The other electrode preferably comprises the walls of the vessel in which separation takes place. The dielectrophoresis separation process may be assisted by reducing the solubility of the wax &c. in the feedstock by adding a light petroleum naptha or by cooling. Other additives referred to comprise chlorinated hydrocarbons, terpolymers based on vinyl acetate, petroleum resins and known filter aids. Wax &c. may be removed from electrodes by scraping with a blade, heating, e.g. electrically using a secondary electrode, dissolving, e.g. using propane, filtering, centrifuging, gravitational settling or flotation. An inert nitrogen atmosphere may be used over the feedstock. Specific particulate electrodes comprise the liquids water, glycols (e.g. diethylene glycol), fluorcarbons, liquid ammonia, amines and esters and the solids polyvinylchloride, carbo-waxes, metals, alloys, sulphonated resins, other polyelectrolytes, and inorganic salts. The particles may be charged and/or formed by passing through or near a charged metal grid or electrodes. These forms of suitable apparatus are diagrammatically illustrated in Figs. 1 and 2 (not shown).