Ethanol is a clean burning, biodegradable alternative fuel source gaining more and more popularity for its ease of production and significant reduction in green house gas emissions. While 100%, or neat, ethanol is currently not ideal for use in motor vehicle engines yet; it is quite common in gasoline/ethanol blends.
Ethanol is soluble in water and may corrode some rubbers. Its solvent action may also require other special considerations when storing and using ethanol blends.
Different ethanol blends require different storage approaches. The higher the concentration of ethanol in a blend, the more corrosive it becomes to certain rubbers, plastics, and metals. Therefore special storage considerations must be taken into account for each type of blend.
E10’s corrosive, solvent, and phase separation properties can adversely impact storage tank systems. Owners must also consider ethanol permeability and compatibility of metals and certain rubbers and elastomers when storing this E10. Older seals and gaskets on existing tanks should be replaced with synthetic varieties to prevent leakage. Marina owners have reported high occurances of problems when storing E10 is fiberglass fuel storage tanks.
Phase separation is a particular concern, as separated ethanol blends can impact vehicle performance to the point of breakdown. During phase separation, the gasoline and ethanol in the blend separate. Ethanol and water sink to the bottom, while gasoline containing trace methanol concentrations rises to the top. The result is an imbalanced blend that most likely contains water, and will almost certainly impair, if not ruin an engine.
Those owners who convert existing petroleum fuel storage tanks to E10 should completely clean and inspect tanks for damage and existing corrosion before converting to an ethanol blend. Also, it is imperative that all water be completely removed from the tank. Fuel storage tanks used for E10 should never have any amount of soft metals like zinc or aluminum in any metal parts. Tank components containing elastomers, polymers, rubber, polyurethane, and dissolved alcohol based glues and pipe sealants are all vulnerable to the effects of ethanol blends. In addition, ethanol blends should be checked frequently for particulates, water, and impurities to protect tanks and engines.
E85 ethanol blend requires even more care and consideration when storing than E10. This is because the high concentration of ethanol in the mixture results in a more corrosive blend which can cause serious problems when incompatible materials are used, or when it is stored improperly or in an improperly prepared tank.
E85 can corrode aluminum, zinc and other soft metals as well as brass, copper, and lead, and its scouring action loosens deposits and sludge inside engines. E85’s corrosive nature can exacerbate existing corrosion in steel tanks. If tanks are not properly cleaned and inspected before the addition of E85, leakage and possible environmental contamination may occur. Tank owners should be especially vigilant regarding fuel filters. Improperly sized filters or filters of the wrong grade can allow impurities into fuel and engines.
It is important to follow specific guidelines when storing E85 ethanol. Failure to use correct tank and component material will result in leakage, environmental contamination, and fuel contamination.
All tanks housing E85 blends should be double walled and constructed of steel, fiberglass-jacketed steel, or UL-listed fiberglass. Approved alternative fuel probes must be used, as petroleum probes do not read ethanol blends properly. Typically, existing spill buckets are approved for ethanol blend usage.
Inspect tanks frequently for moisture, particulates, and separation to ensure the fuel is of a dispensable quality. As E85 is highly corrosive, be vigilant in tank, pipe, and hose inspection. Any flaws or pre-existing corroded areas will be compounded by E85.
Important Points to Remember
Both E10 and E85 ethanol blends produce far less air pollutants than gasoline, making them ideal for fleets to meet stringent emissions guidelines set forth by the government; however, these blends have corrosive properties and readily mix with water. Therefore, it is imperative that tanks and all tank components be constructed of the proper materials and monitored extremely closely to maintain safety.