WO1994017165B1

WO1994017165B1 - Improved liquid decontamination apparatus and method

Info

Publication number: WO1994017165B1
Application number: PCT/US1994/000883
Authority: WO
Filing date: 1994-01-21
Publication date: 1994-09-15

Abstract

In a multi-pass system for purifying oil or other liquids, an improved apparatus and method for mixing air with the contaminated liquid for separation after a phase change from liquid to gas. The contaminated liquid is drawn from a reservoir (10) by a pump (14), filtered (18), and heated (20), and atmospheric air is induced into the contaminated liquid downstream of the heater by an eductor (22, 50) which promotes the phase change from liquid to vapor. The liquid/contaminant mix, which now includes entrained air, is passed immediately through a second eductor (22, 60), the compressibility of the air in the mix, followed by expansion of the compressed air as the mix exits the second eductor, causing intimate contact of air and contaminant, thereby promoting the stripping of the contaminant from the liquid. The air/liquid/contaminant mix is then routed to a level controlled separation tank (24), water vapor, contaminants, and condensate being released from the tank in the space above the pooled liquid. Purified, dry liquid is drawn from the tank by a second pump (14) and delivered back to the reservoir.

Claims

/AMENDED CLAIMS[received by the International Bureau on 16 August 1994 (16.08.94); original claims 1-10 replaced by amended claims 1-10 (3 pages)]

1. Apparatus for decontaminating contaminated liquid stored in a reservoir, comprising: a pump (14) for moving the contaminated liquid out of a reservoir (10) ; 5 means (20) for heating the contaminated liquid pumped out of the reservoir; first mixing means (50), having a nozzle (52), a suction port (53) and an outlet (54), for receiving the contaminated liquid from the heating means and drawing in

10 and mixing a gas through the suction port with the contaminated liquid; and, a separation chamber (24) for receiving the mixture of gas and contaminated liquid, characterised by: a second mixing means (60), having a nozzle (62), a

15 suction port (63) and an outlet (64), wherein the outlet of the first mixing means is connected directly with the nozzle of the second mixing means, the nozzle of the second mixing means being larger than the nozzle of the first mixing means for receiving the contaminated liquid gas

20 mixture from the first mixing means and drawing in and mixing a gas through the suction port with the mixture; and in that the chamber is connected with the outlet of the second mixing means for receiving the mixture of gas arid contaminated liquid therefrom, in which chamber the gas and

25 contaminate move to the top of thereof and the liquid falls to the bottom, thereby decontaminating the liquid.

2. Apparatus as claimed in Claim 1, wherein the ratio of the areas of the nozzles to the area of the throats of. the respective first and second mixing means is between about 0.6 and about 0.3 for operating temperatures from about 65.6°C to about 87.8°C.

3. Apparatus as claimed in Claim 1 or 2, wherein, in use, a factor H for relationships between the pressures P*,_^ at the nozzle inlet of the first mixing means, P₂ at the diffuser outlet of the first mixing means, and P₃ at the suction port of the first mixing means is H = (P₂ - P₃)/(P₁ - P₂) , H ranging between 0.15 and 0.35 at pressures of less than 0.35155 kg/mm².

4. Apparatus as claimed in Claim 3, wherein the factor H of the second mixing means is about 0.59 at pressures of less than about 0.07031 kg/mm².

5. Apparatus as claimed in Claim 1, 2, 3 or 4, wherein the area of the nozzle A_n of the second mixing means is given by the formula:

P-_L - P₃ = 11.11 * (1 + X * (P_i/Ps) * ((d/772 * Q_n/A_n)²)), where, in use, P*-_^ is the pressure at the nozzle inlet, P₃ is the pressure at the suction port, x is the air to oil volumetric ratio, d is the density of the incoming mix of contaminated liquid and gas, and Q_n is the mass flow rate through second mixing means.

6. Apparatus as claimed in any Claims 1 to 5, wherein a collector plate (90) is suspended in the separation chamber above the connection to the outlet port of said second mixing means for preventing re-contamination of the liquid from condensate formation.

7. A method of decontaminating a liquid comprising the steps of: pumping a contaminated liquid out of a reservoir (10) ; heating the contaminated liquid; causing the heated, contaminated liquid to flow through a reduced flow area; expanding the heated, contaminated liquid so as to draw gas into the flow under conditions of selected temperature and pressure, thereby producing a flow of liquid, contaminant, and gas; and flashing the vaporized contaminant from the flow; characterised by: compressing the flow of the expanded liquid, contaminant, and gas; and thereafter expanding the compressed flow of liquid, contaminant, and gas so as to draw additional gas into the flow and cause severe turbulence therein, thereby increasing the gas to liquid ratio in the flow and promoting intimate contact between the gas and the liquid.

8. A method as claimed in Claim 7, wherein the contaminated liquid is heated to a temperature of from about 65.6°C to about 87.8°C.

9. A method as claimed in Claim 7 or 8, wherein the pressure of the contaminated liquid from the reduced area flow before the first expansion is under about 0.35155 kg/mm².

10. A method as claimed in Claim 7, 8 or 9, wherein the pressure of the flow of liquid, contaminant, and gas from the compression step before the second expansion is under about 0.07031 kg/mm². STATEMENT UNDER ARTICLE 19

In accordance with Article 19 the Patent Cooperation Treaty (PCT) Applicant files this Amendment within two months of the receipt of the Notification of Transmittal of the International Search Report or Declaration, which was received on June 27, 1994.

Applicant submits the enclosed replacement sheets 18-20 to replace the pages 18-20 filed in the original application. As required by Article 19, Applicant provides the following explanation of the amendment to the claims:

Original Claims 1 through 10 are replaced by amended Claims 1 through 10.

Applicant also presents the following statement to specify the impact that the amendments presented in the Article 19 Amendment have on the description:

The temperatures and the pressures indicated in the claims were converted to metric units and similar changes will have to be made in the specification. Each claim was also reorganized into a format that is more conducive to the European Patent Office practice.