| 摘要 |
<p>1468512 Separating oil-water emulsions MIDLAND OIL REFINERIES Ltd 10 June 1974 [9 June 1973] 27558/73 Addition to 1383747 Heading C5E Oil is recovered from a soluble oil emulsion by a continuous flow multistage process in which the liquid is treated in successive compartments by mixing with a Group II metal salt, mixing with a trivalent metal salt, withdrawing separated oil, adding an alkali to precipitate the Group II and trivalent metals and draining the remaining aqueous liquid from the settled precipitate. The pH of emulsion from a reservoir 1 is adjusted to 7 or below by the addition of sulphuric or hydrochloric acid from reservoir 21 or of sodium hydroxide from reservoir 22 in response to a pH sensor 18. 30% w./v. aqueous calcium chloride or magnesium chloride from reservoir 24 is mixed with the pH-adjusted emulsion in compartment 23, the emulsion is then passed through a second mixing compartment 28 in which 40% w./v. ferric chloride or aluminium sulphate from reservoir 31 is added to the emulsion as it leaves the compartment 28 and passes into the separating compartment 33. Separated oil is removed from the surface of the liquid in compartment 33 and passed through lines 35 and 36 to the oil reservoir 10. The remaining aqueous phase of the treated emulsion is neutralized in the compartment 37, which has a pH sensor 38 which controls the addition of sodium hydroxide from the reservoir 22, and then passed through the settlement compartment 40 into a settlement tank (46, Fig. 2, not shown) into which a polyelectrolyte from reservoir 46 can be added to facilitate precipitation of solids as a sludge. The Group II and trivalent metal salts are preferably added in a mole equivalent ratio between 5 : 1 and 15 : 1.</p> |
