Multi-stage engine coolant recycling process

• US 6,187,197 B1
• Filed: 10/28/1998
• Issued: 02/13/2001
• Est. Priority Date: 10/28/1998
• Status: Expired due to Fees

• Current Assignee: Marvin Haddock
• Original Assignee: Marvin Haddock
• Inventors: Haddock, Marvin
• Primary Examiner(s): Walker, W. L.
• Assistant Examiner(s): Ward, Richard W.
• Application Number:
  US09/182,393
• Time in Patent Office: 839 Days
• Field of Search: 210/641, 210/652, 210/703, 210/787, 210/806, 210/900, 210/258, 210/259, 204/542, 204/544, 568/868
• US Class Current: 210/641
• CPC Class Codes: B01D 61/025 Reverse osmosis; Hyperfiltration
• CPC Class Codes: B01D 61/026 comprising multiple reverse osmosis steps
• CPC Class Codes: B01D 61/027 Nanofiltration
• CPC Class Codes: B01D 61/029 Multistep processes comprising different kinds of membrane processes selected from reverse osmosis, hyperfiltration or nanofiltration
• CPC Class Codes: B01D 61/04 Feed pretreatment
• CPC Class Codes: B01D 61/145 Ultrafiltration
• CPC Class Codes: B01D 61/48 having one or more compartments filled with ion-exchange material , e.g. electrodeionisation
• CPC Class Codes: B01D 61/58 Multistep processes
• CPC Class Codes: F01P 11/06 Cleaning in general B08B; Combating corrosion in general C23F
• CPC Class Codes: F01P 2011/061 Cleaning or combating corrosion using filters
• CPC Class Codes: F01P 2011/063 Cleaning F01P2011/061 takes precedence

Abstract

A multi-stage apparatus and a process for recycling used engine coolant employs a combination of filtration, dissolved air floatation, centrifugation (hydrocyclone separation), semi-permeable nano filtration, reverse osmosis, and continuous deionization for separating ethylene glycol, with or without propylene glycol, and water from used engine coolant. The engine coolant is pre-filtered through a series of filters. The filters remove particulate contaminates. This filtered fluid is then subjected to dissolved air floatation and/or centrifugation to remove organic petroleum contaminants. Then, it is pressurized prior to being passed through semi-permeable nano filtration. The nano filtration separates the feed stream into a ultra filtration solution and a concentrated waste solution. The concentrate solution is returned to a centrifuged coolant tank for continuous circulation through the nano filtration device. The ultra filtration solution is pressurized and passed through a reverse osmosis device, which separates the feed stream into a permeate solution and a concentrated waste solution. The concentrated waste solution is returned to a ultrafiltrate solution tank for continuous circulation through the reverse osmosis device. The permeate solution is subjected to final refining by continuous deionization which reduces ionic contaminants. Depending upon environmental conditions, a heater and/or heat exchanger maintain the temperature of the process solution within an optimum pre-established operating temperature range.

Claims

1. A process for purifying a glycol-based engine coolant, comprising:

a) providing a contaminated glycol-based coolant to be purified;

b) treating at least a portion of said coolant with a reverse osmosis process;

c) treating at least a portion of a glycol containing permeate from said reverse osmosis process with an electrolysis deionization process;

d) collecting at least a portion of the permeate treated by said electrolysis deionization process as purified glycol-based coolant.

2. The process for purifying engine coolant according to claim 1, wherein the purified engine coolant meets ASTM coolant standards as detailed in FIG. 5.

3. The process for purifying engine coolant according to claim 1, further comprising filtering said coolant.

4. The process for purifying engine coolant according to claim 3, further comprising filtering said coolant prior to passing said coolant through said reverse osmosis process.

5. The process for purifying engine coolant according to claim 3, further comprising filtering said coolant by at least two filters positioned in series along a flow path.

6. The process for purifying engine coolant according to claim 5 wherein the filters in series have decreasing pore size.

7. The process for purifying engine coolant according to claim 1, further comprising subjecting said coolant to dissolved air floatation prior to passing said coolant through said reverse osmosis process.

8. The process for purifying engine coolant according to claim 1, further comprising removing particulate matter from sad coolant by centrifugation.

9. The process for purifying engine coolant according to claim 8, wherein said centrifugation occurs prior to passing said coolant through said reverse osmosis process.

10. The process for purifying engine coolant according to claim 1, further comprising filtering said coolant with semi-permeable nano filtration.

11. The process for purifying engine coolant according to claim 10, wherein said semi-permeable nano filtration occurs prior to passing said coolant through said reverse osmosis process.

12. The process for purifying engine coolant according to claim 10, further comprising pressurizing said coolant to a pressure of 350 to 600 psi in performing said semi-permeable nano filtration.

13. The process for purifying engine coolant according to claim 1, further comprising pressurizing said coolant to a pressure of 50 to 300 psi prior to passing through said reverse osmosis process.

14. The process for purifying engine coolant according to claim 13, further comprising pressurizing said coolant to a pressure of 350 to 600 psi prior to passing through a semi-permeable nano filtration.

15. The process for purifying engine coolant according to claim 1, wherein the glycol-based coolant comprises ethylene glycol.

16. The process for purifying engine coolant according to claim 1, wherein the glycol-based coolant comprises propylene glycol.

17. The process for purifying a glycol-based coolant according to claim 1, further comprising the following process steps conducted prior to said reverse osmosis process:

a) filtering said coolant;

b) subjecting said coolant to dissolved air floatation;

c) removing particulate matter from said coolant by centrifugation; and

d) filtering said coolant with semipermeable nano filtration.