Patent EA-004111-B1 (EA)
Title: A plant for purifying water contaminated by droplets of hydrocarbonaceous liquid
Inventor: OSEROED STEIN EGIL
IPC: B01D17/00
Filed: 2001-08-07
Abstract: 1. A plant for purifying water contaminated by droplets of hydrocarbonaceous liquid and possibly other pollutants, comprising: an essentially vertically positioned filter (4); an inlet chamber (7) for said contaminated water partially defined by a first vertical surface (5) of said filter; an outlet chamber (11) for filtrated water partially defined by a second surface (6) of said filter opposite to said first surface (5) relative to the filter; supply means (8) for contaminated water debouching in the lower portion of said inlet chamber (7) ; outlet means (9) connected to the upper portion of said inlet chamber (7) for discharging hydrocarbonaceous liquid separated from the water in said inlet chamber; and duct means (12) for recovering purified water from said outlet chamber; characterized in having means (16,17, 18,19) for injecting gas as fine bubbles into the contaminated water at least at one location selected from locations in the lower portion of said inlet chamber. (7) and locations in said supply means (8) to produce a stream of gas bubbles upwards along said first vertical filter surface (5) to release and remove upwards droplets of hydrocarbonaceous liquid and vapour bubbles settled on the filter surface (5) and to entrain and remove upwards such droplets and vapour bubbles otherwise prone to settle on the filter surface, thereby delaying blocking of the filter surface and promoting a merging of said droplets to form a continous hydrocarbonaceous phase in said upper portion of the inlet chamber (7). 2. A plant according to claim 1, characterized in that the filter (4) comprises a particulate, elastic, oil-sorbing, regeneratable filter material enclosed between two liquid-pervious supporting sheets forming said first vertical surface (5) and said second surface (6), resp. 3. A plant according to claim 1 or 2, characterized in that said outlet chamber (11) is shaped as a vertical, rotational symmetrical cylinder; said filter (4) is coaxially surrounding said outlet chamber and has an annular, horizontal cross-section; and said inlet chamber (7) forms a jacket around the filter and has an annular, horizontal cross-section. 4. A plant according to claim 1,2 or 3, characterized in that said means for injecting gas into the contaminated water is at least one nozzle (18) inserted in the bottom portion of the inlet chamber and connected to a source of pressurized air. 5. A plant according to claim 4, characterized in that said at least one nozzle (18) is a plurality of nozzles evenly spread at the same horizontal level in the bottom portion of the inlet chamber (7) to produce an even sweeping upward flow of bubbles through the water in the inlet chamber in the vicinity of the filter surface (5). 6. A plant according to any one of the claims 1, 2 or 3, characterized in that said means for injecting gas into the contaminated water is at least one nozzle (19) inserted in said supply means (8) and connected to a source of pressurized air, said at least one nozzle being able to disperse air evenly into the contaminated water before it reaches the bottom portion of the inlet chamber (7). 7. A plant according to any one of the preceding claims, characterized in that further having means for introducing a flotation promoting agent into the contaminated water in the supply means therefore or in the lower portion of said inlet chamber. 8. A plant according to any one of the preceding claims, characterized in that said outlet means (9) for hydrocarbonaceous liquid is designed to discharge also gas from the upper portion of the inlet chamber (7). 9. A plant according to any one of the claims 1 to 7, characterized in that having separate discharge duct means (10) for spent flotation gas in the upper portion of said inlet chamber (7). 10. A plant according to any one of the preceding claims, characterized in that having means for introducing CO2 into the contaminated water, said means being the same as those (16,17,18,19) applied for injecting gas or being separate means placed in the lower portion of the inlet chamber (7) or in said supply means (8) thereto. 11. A plant according to claim 2, characterized in that the liquid-pervious sheet forming said first vertical surface (5) of the filter is of metal and has slot openings of a width from 15 mum to 1 mum, preferably from 15 mum to 50 mum. 12. A plant according to claim 2, characterized in that the filter (4) comprises a filter material between the surfaces (5) and (6) which material is an organic polymer in granulated form having high compressibility.