Coolant Recycling System Process Description

The EET Corporation Coolant Recycling System (CRS) is a patented multi-stage process that uses a combination of electro-physicochemical methods to recover used antifreeze and produce an upcycled engine coolant indistinguishable from virgin products. This is accomplished by use of two separate unit operations that remove contaminants and residual corrosion inhibitors typically found in used engine coolants. A dry non-hazardous filter cake and saltwater brine are the only major by-products of the CRS process.

Pretreatment of used engine coolant plays a vital role in the overall effectiveness of the process. The EET physical-chemical pretreatment system uses chemical precipitation/flocculation and powdered activated carbon (PAC) adsorption. A pre-coat type filter press is used to separate, concentrate and dewater contaminants and is specifically designed for pretreatment of used antifreeze. Use of this process will result in removal of dyes, soluble oils, hydrocarbons, dissolved heavy metals and suspended solids to very trace to non-detectable levels resulting in enhanced down-stream desalting performance.

High Efficiency Electro-Pressure Membrane (HEEPM™) is a patent-pending process employing an integrated approach to deionization. HEEPM™ uses multiple types of highly efficient electrodialysis (HEED®) membrane units operated in an integrated configuration with a nanofiltration (NF) unit. In the HEEPM™ integrated arrangement, ED serves to maintain or lower the feed to the NF membrane elements and, as a result, the NF permeate quality remains high even at high overall recoveries. In addition, the recycled NF concentrate serves to maintain the ED feed at levels that provide the most efficient current utilization and separations. The effect of this integration is that the ED and NF sub-systems work synergistically, each operating in the respective optimal range.

NF is a physical process in which contaminants are removed by applying pressure on the feed water to direct it through a semi permeable membrane. HEED® is an electrochemical process in which ions migrate through semi permeable membranes as a result of their attraction to two electrically charged membrane surfaces. The basic principles of both processes are illustrated below.

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