Multi-stage engine coolant recycling apparatus and process

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 contaninates. 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.

What is claimed is:  
     
         1 . A process for purifying engine coolant, comprising: 
 a) providing engine coolant to be purified;    b) treating said coolant through a reverse osmosis process;    c) treating said coolant through a electrolysis deionization process; and    d) collecting purified coolant.    
     
     
         2 . The process for purifying engine coolant according to  claim 1 , wherein the purified coolant meets ASTM standards.  
     
     
         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 said 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 said semi-permeable nano filtration.  
     
     
         15 . A process for purifying engine coolant comprising: 
 a) providing engine coolant to be purified;    b) filtering said coolant;    c) subjecting said coolant to dissolved air floatation;    d) removing particulate matter from said coolant by centrifugation;    e) filtering said coolant with semi-permeable nano filtration;    f) passing said coolant through a reverse osmosis process; and    g) passing said coolant through electrolysis deionization process.    
     
     
         16 . A process for purifying engine coolant, comprising treating said coolant to a reverse osmosis process wherein a purified coolant meets ASTM standards as detailed in FIG. 5.  
     
     
         17 . An apparatus for purifying engine coolant, comprising: 
 a) a reverse osmosis separator through which said coolant is passed;    b) a electrolysis deionizer; and    c) a purified coolant collector.    
     
     
         18 . The apparatus according to  claim 17 , further comprising a filter.  
     
     
         19 . The apparatus according to  claim 18 , wherein said filter is positioned along a flow path before said reverse osmosis separator.  
     
     
         20 . The apparatus according to  claim 19 , further comprising at least two filters positioned in series.  
     
     
         21 . The apparatus according to  claim 20 , wherein said filters in series have decreasing pore size.  
     
     
         22 . The apparatus according to  claim 17 , further comprising a dissolved air floatation separator through which said coolant is passed prior to passing through said reverse osmosis separator.  
     
     
         23 . The apparatus according to  claim 17 , further comprising a centrifuge through which said coolant is passed prior to passing through said reverse osmosis separator.  
     
     
         24 . The apparatus according to  claim 17 , further comprising a semi-permeable nano filtration process through which said coolant is passed prior to passing through said reverse osmosis separator.  
     
     
         25 . The apparatus according to  claim 24 , further comprising a pressurizer to pressurize said coolant to 350 to 600 psi prior to passing through said semi-permeable nano filtration process.  
     
     
         26 . The apparatus according to  claim 17 , further comprising a pressurizer to pressurize said coolant to 50 to 300 psi prior to passing through said semi-permeable reverse osmosis process.  
     
     
         27 . The apparatus according to  claim 26 , further comprising a pressurizer to pressurize said coolant to 350 to 600 psi prior to passing through said semi-permeable nano filtration process.