Ethanol (ethyl alcohol) is the alcohol used to create beer, wine and other alcoholic beverages. Ethanol is also produced as an alternative fuel to gasoline. In the U.S., more than 9 billion gallons of ethanol fuel is produced annually. Ethanol is typically produced from corn or sugarcane. The U.S...
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The transfer and storage of grain at the ethanol plant is like any other grain elevator operation — there is the potential for dust explosion from the grain dust. Grain is dumped into a collection pit and transferred into the storage bins at the facility. Dust-control equipment is in place to reduce the chances of dust explosions. The elevator has an external leg that is equipped with explosion venting. The leg transfers the grain to and from the storage silos. Stored grain generally contains two to 10 pounds of grain dust per ton.
Ethanol is a flammable liquid, according to the U.S. Department of Transportation (DOT). It is shipped under the red flammable liquid placard with the United Nations four-digit identification number 1987, which is used for all alcohols. Other hazardous materials located at a typical ethanol plant include anhydrous ammonia (NH3), sulfuric acid, phosphoric acid, ferric chloride and sulphamic acid (for cleaning tanks). Welding gases are also present in maintenance shop areas.
Anhydrous ammonia and sulfuric acid are trucked into the plant twice weekly and stored in large tanks outside the plant. They are piped inside the facility for use in the ethanol production process. Anhydrous ammonia is a toxic corrosive gas, which is also flammable, especially when inside of a facility or an enclosed area. It is classified by the DOT as a non-flammable gas because it does not meet the DOT definition of flammable gas. Anhydrous ammonia is classified as a 2.3 toxic gas under the United Nations Hazard Class System. The National Fire Protection Association (NFPA) 704 standard classifies anhydrous ammonia as Health Hazard 3, Flammability 1 and Reactivity 0. The important points to remember about anhydrous ammonia are its toxicity and flammability since it is piped into the ethanol production facility. A leak inside the plant could result in an explosion or fire if it encounters an ignition source. Contact with the skin, particularly if the skin is moist, will cause severe burns. Contact with the eyes can cause blindness. The word anhydrous means without water. As a result, anhydrous ammonia seeks water and will affect moist areas of the body.
Sulfuric acid is corrosive and toxic and one of the top industrial chemicals in terms of total production quantity in the U.S. The DOT classifies sulfuric acid as a Class 8 Corrosive Liquid. Phosphoric acid is also a Class 8 Corrosive Liquid. Both sulfuric and phosphoric acids are listed under the NFPA 704 classification system as Health Hazard 3, Flammable Hazard 0 and Reactivity Hazard 2. They cause severe burns in contact with skin. Ferric chloride is corrosive and can cause burns on skin contact. It is listed by NFPA 704 as Health Hazard 3, Flammability 0 and Reactivity 2. The DOT classifies ferric chloride as a Class 8 corrosive solid. Sulphamic acid is corrosive and can cause burns in contact with skin. It is classified the same as ferric chloride.
Production of ethanol begins by extracting starch from the corn. Corn is moved into the process facility on a conveyor and placed into tanks. Enzymes are used to extract the starch from the corn and it is turned into sugar. Yeast is then mixed into the sugar in 8,000-gallon fermentation tanks. It is the fermentation process that ultimately produces ethanol. Fermentation creates heat and circulating water is used to cool the process to 91 degrees Fahrenheit for the yeast to work properly. Sulfuric acid is used to clean equipment and adjusting the pH for optimum fermentation. Anhydrous ammonia is used for pH correction and supplies nutrients for the yeast.
When the process is finished, 200-proof ethanol is produced. It is then denatured with 2.5% natural gasoline produced from natural gas. Denaturing is done to prevent the ethanol from being used as drinking alcohol. The finished product is 190 proof and is stored in 200,000-gallon closed floating roof tanks at the facility. Production capacity at the Fairmont plant is 3 million gallons and there are usually 1 million gallons on hand. Ethanol produced at Fairmont is shipped by rail to Dallas/Fort Worth, TX, and California. There are 96 to 112 rail cars on site at any given time, each with a capacity of 30,000 gallons of ethanol. Railcars are filled at a specially designed loading rack. The rail car loading rack is protected by a 750-gpm deluge system in the event of a fire during the loading process.