Method and apparatus for decontaminating a liquid

• US 5,630,914 A
• Filed: 06/07/1995
• Issued: 05/20/1997
• Est. Priority Date: 09/21/1993
• Status: Expired due to Fees

• Current Assignee: Johnson Matthey Pharmaceutical Materials (Johnson Matthey PLC)
• Original Assignee: Pharm-Eco Laboratories, Inc. (Johnson Matthey PLC)
• Inventors: Sachdeva, Yesh P., Gabriel, Richard L.
• Primary Examiner(s): Manoharan, Virginia
• Application Number:
  US08/478,945
• Time in Patent Office: 713 Days
• Field of Search: 203/72, 203/49, 203/89, 203/DIG. 9, 549/369, 549/377, 549/263, 549/512, 549/541, 568/621, 568/615, 159/13.4, 159/14, 159/49, 159/13.2, 159/16.1, 159/26.2, 159/DIG. 10, 159/DIG. 20, 585/807, 585/810
• US Class Current: 203/49
• CPC Class Codes: B01D 1/0047 in a closed circuit B01D3/007 takes precedence
• CPC Class Codes: B01D 1/22 by bringing a thin layer of the liquid into contact with a heated surface B01D1/065 takes precedence
• CPC Class Codes: B01D 1/26 Multiple-effect evaporating
• CPC Class Codes: B01D 3/346 the gas being used for removing vapours, e.g. transport gas
• CPC Class Codes: B01D 5/0084 Feeding or collecting the cooling medium B01D5/0087 takes precedence
• CPC Class Codes: C08G 65/30 Post-polymerisation treatment, e.g. recovery, purification, drying

Abstract

A method for decontaminating a liquid of a contaminant having a vapor pressure which is higher than the vapor pressure of the liquid. A contaminated liquid is directed through an inclined conduit. A gas is directed into the inclined conduit, whereby the gas contacts the liquid and transports the contaminant, which has volatilized in the inclined conduit, out of the inclined conduit, thereby decontaminating the liquid. The liquid is discharged from the inclined conduit.

Claims

1. A method for decontaminating a liquid of a contaminant having a vapor pressure which is higher than the vapor pressure of the liquid, comprising the steps of:

a) introducing a contaminated liquid, said liquid being selected from a group consisting of silicones, polydienes, epoxies, epoxides, phosphazenes, ethers, esters, caprolactones, sulfides, azalates, chlorinated alkanes and styrenes, into an inclined conduit at an upper portion of the conduit to form a thin film of liquid which flows along and through the inclined conduit, whereby the contaminant is volatilized; and

b) flowing a gas through the conduit and over the thin film of liquid to transport the contaminant, which has volatilized in the conduit, out of the conduit, thereby decontaminating the liquid.

2. The method of claim 1 further including the step of heating the gas which is directed into the conduit to thereby volatilize the contaminant of the liquid in the conduit.

3. The method of claim 1 further including the step of heating the conduit to thereby cause the contaminant in the liquid to volatilize.

4. The method of claim 3 wherein the gas is directed countercurrently to the direction of flow of the liquid.

5. The method of claim 4 wherein the gas is non-reactive.

6. The method of claim 5 wherein the gas is selected from the group consisting of nitrogen, helium, argon, carbon dioxide, methane, and ethanol.

7. The method of claim 3 wherein the gas is directed concurrently with the direction of flow of the liquid.

8. The method of claim 7 wherein the contaminant concentration of the contaminated liquid is in a range of between about 0.5 and 5.0 percent, by weight.

9. The method of claim 8 wherein a resulting contaminant concentration of the liquid after decontamination is less than about five parts per million.

10. The method of claim 9 wherein the temperature of a heat exchanger medium is in a range of between about 120°

and 160°

C.

11. A method for decontaminating a liquid polymer of a solvent contaminant having a vapor pressure which is higher than the vapor pressure of the liquid, comprising the steps of:

a) introducing the contaminated liquid polymer, said liquid polymer being selected from a group consisting of silicones, polydienes, epoxides, phosphazenes, ethers, esters, caprolactones, sulfides, azalates, chlorinated alkanes and styrenes and has a glass transition temperature of about 15°

C. or less, through an inclined conduit to form a thin film of liquid which flows along the inclined conduit, whereby the solvent contaminant is volatilized; and

b) flowing a gas through the conduit and over the thin film of the liquid polymer to transport the solvent contaminant, which has volatilized in the conduit, out of the conduit, thereby decontaminating the liquid polymer.

12. The method of claim 11 wherein the contaminant is dimethylformamide.

13. The method of claim 11 wherein a resulting contaminant concentration of the liquid polymer is less than about one hundred part per million.

14. The method of claim 13 wherein the temperature of a heat exchanger medium is in a range of between about 120°

and 160°

C.

15. The method of claim 11 wherein the liquid polymer is the epoxies.

16. A method for decontaminating a liquid of a contaminant having a vapor pressure which is higher than the vapor pressure of the liquid, comprising the steps of:

a) introducing a contaminated liquid said liquid being selected from a group consisting of silicones, polydienes, epoxies, epoxides, phosphazenes, ethers, esters, caprolactones, sulfides, azalates, chlorinated alkanes and styrenes, into an upper conduit at an upper portion of the upper conduit to form a first thin film of liquid which flows along and through the upper conduit, whereby the contaminant is volatilized;

b) flowing a gas through the upper conduit and over the first thin film of liquid to transport the contaminant, which has volatilized in the upper conduit, out of the upper conduit, thereby at least partially decontaminating the liquid;

c) discharging the partially decontaminated liquid from a lower portion of the upper conduit into a middle conduit at an upper portion of the middle conduit to form a second thin film of liquid which flows along and through the middle conduit, whereby contaminant is volatilized;

d) flowing a gas through the middle conduit and over the second thin film of the partially decontaminated liquid to transport the contaminant, which has volatilized in the middle conduit, out of the middle conduit, thereby further decontaminating the liquid;

e) discharging the further partially decontaminated liquid from a lower portion the middle conduit into a lower conduit at an upper portion of the lower conduit to form a third thin film of liquid which flows along and through the lower conduit, whereby the contaminant is volatilized; and

f) flowing a gas through the lower conduit and over the third thin film of the further partially decontaminated liquid to transport the contaminant, which has volatilized in the lower conduit, out of the lower conduit, thereby decontaminating the liquid.