Ethanol has been in the news a lot lately and, as the result of phase separation, is believed to have contributed to the failure of a fuel filter installed in a CTSW.
Ethanol absorbs water and blends well with gasoline. However, too much water will overwhelm the ethanol’s ability to remain blended with the gasoline. Because ethanol mixes easier with water than gasoline, it will separate from gasoline and accumulate with the water at the lowest point of a system. The product in the tank will no longer be a homogeneous blend of ethanol and gasoline, but two layers of product; a layer of gasoline on top and an ethanol/water layer on the bottom. This is referred to as “phase separation.”
