The 411 About Ethanol


What is ethanol made of?

Ethanol is made from various plant materials, which are collectively known as biomass. The majority of gasoline pumped into cars in the US contains ethanol. This ethanol-gasoline blend is called E10, which is 10% ethanol and 90% gasoline. This helps to oxygenate the fuel and reduce air pollution.

Who produces ethanol?

Ethanol is produced using corn in the US, sugar cane in Brazil, and crop residues and wood chips elsewhere in the world. In fact, Brazil was able to end its dependence on foreign oil thanks in part to ethanol.

Ethanol is also available in a higher blend, known as E85. This fuel can be used in flex-fuel vehicles, which are engineered to run on E85 or E10.

How is ethanol made?

The production of ethanol begins with growing, collecting, and transporting plants to a production facility. Plant sugars are then broken down and fermented to produce pure ethanol. This is no different from grain alcohol, so a minimum of 2% hydrocarbons is added to make it unfit for human consumption.

Because different hydrocarbon components are used in E85, its range of vapor flammability is wider than that of gasoline. E85 can produce flammable vapors from temperatures as high as 28 degrees Fahrenheit, and as low as 8 degrees Fahrenheit. Given this high volatility, service stations and C-stores should not store unblended ethanol, as there is a high risk of explosion.

How is ethanol stored?

Certain materials used with gasoline can become incompatible with E10 and E85 blends. Ethanol blends have been shown to cause corrosion of softer metals such as lead, brass, aluminum, and zinc. Additionally, E85 acts as a cleaning agent, and can stir up sludge that has collected on the bottom of fuel storage tanks. This sludge is then suspended in the fuel, drawn up through the pumps, and into customer vehicles. Tanks made of unplated steel, stainless steel, bronze, and black iron are all resistant to corrosion, and can be used to store ethanol-blended fuels.

Aboveground tanks designed to store ethanol are constructed of either stainless steel or carbon steel. It is not recommended to use either plastic or galvanized metal tanks, as they can corrode.

How is an ethanol tank maintained?

An optic sweep is the first line of defense in tank cleaning. A fiber-optic camera is lowered into the tank, along with an extraction device. This system can be used to locate and eradicate debris, sludge, and bacteria while keeping the storage tank full. Another option is to use a filter agitator, which stirs up the debris accumulated at the bottom of the tank. The fuel is then filtered and cleaned of debris. Chemical solvents can also be used to remove debris, which is then pumped out of the tank. Finally, the last option is to drain the tank and have a team of individuals steam-clean it from the inside out. The type of service you choose will depend on the kind of fuel stored in the tank, as well as environmental regulations.

When an underground tank is used, cleaning is recommended if the tank was previously used to store a different type of fuel. During fuel storage, debris and moisture can make its way into the tank, causing sludge to form. There are a number of methods that can be employed to clean sludge, and Clean Fuels knows them all.