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Feedstock
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Feedstock is raw material used for processing or manufacturing another product. Examples of feedstock include crude oil, which is used to produce gasoline, corn, which is used to produce ethanol, and soybean oil, which is used to produce biodiesel.[1]
Background
Feedstock is a general term referring to material that is used to make fuel. A common form of feedstock in renewable fuel production is biomass feedstock, which is material from algae, plants, and animals used to produce biofuels. Biofuels are produced directly from organic matter, whereas fossil fuels like coal, oil, and natural gas are produced after layers of sedimentary rock, soil, and sand have exerted downward pressure on plant and animal remains over millions of years. Biomass feedstocks like corn starch, sugarcane juice, and crop residues are used to produce ethanol, butanol (an alcohol produced by the fermentation of sugars), and biodiesel.[2]
The Energy Independence and Security Act of 2007 established that biofuels must come from feedstocks that qualify as renewable biomass, which include materials that can be replenished within a short period of time. These materials include the following:[3][4]
- Crop residues, including corn leaves and cobs, wheat straw, and citrus residue
- Forest materials, including removed tree branches and wood chips
- Crops planted to prevent soil erosion and maintain soil quality, such as winter rye, peas, and ryegrass
- Food that is discarded or uneaten
- Yard waste, such as grass clippings, leaves, branches, and twigs
- Perennial grasses (grasses that live for more than two years), such as switchgrass
Feedstocks and fuel production
The two most common fuels made from biomass feedstocks are ethanol and biodiesel.
Ethanol production
Ethanol, known as grain alcohol, is distilled from corn or soybeans. Since corn is abundant in the United States, most ethanol is produced from corn. Many ethanol plants are located near consistent supplies of corn, water, and livestock to ensure efficient transportation. More advanced ethanol plants grind corn kernels into small particles and add water and enzymes to prepare a mixture for fermentation. After the mixture is cooked, an enzyme known as glucoamalyse is used to break down the liquid into sugars. Once yeast is added, the mixture is fermented to create ethanol and carbon dioxide. The ethanol is then heated into vapor that is collected, cooled, and condensed into a liquid. After the liquid is dehydrated to remove extra water, the ethanol becomes suited for blending with gasoline. A major byproduct of ethanol is distillers grain, which is high fiber and thus can be fed to beef and dairy cattle, poultry, and pigs.[5]
According to the U.S. Energy Information Administration, in 2015 the United States produced 1,998 trillion British Thermal Units (BTUs) of total corn and other biomass feedbacks used for producing ethanol that would eventually become fuel ethanol.[6][7]
Biodiesel production
Biodiesel is made from several feedstocks, such as animal fats, soybean oil, and used cooking oil. The chemical process used to produce biodiesel is known as transesterification. During this process, flammable liquid alcohol and a catalyst (a substance that increases the rate of a chemical reaction without changing its own chemical constitution) are mixed with vegetable oil or animal fats to separate glycerin from the oil or fat. Glycerin is a sugar that is widely used to make cosmetic products and soaps. The other byproduct of this process is the actual biodiesel, which is sometimes washed with warm water to remove any residual glycerin or catalyst. After biodiesel is produced, biodiesel plants use technology to make sure that the fuel does not contain any remaining glycerin, alcohol, catalyst, or fatty acids. This is done to ensure that the biodiesel runs smoothly in diesel engines.[8][9]
According to the U.S. Energy Information Administration, the United States produced 7.3 billion tons of feedstocks for biodiesel production in 2015. This included the following:[10]
- 745 million pounds of canola oil
- 1.05 billion pounds of corn oil
- 1 million pounds of palm oil (edible vegetable oil derived from fruit)
- 197 million pounds of poultry fats
- 429 million pounds of beef or mutton fats
Federal departments
The U.S. Department of Agriculture (USDA) monitors the market for feedstocks and collects data on feedstock production, consumption, and prices. The Bioenergy Technologies Office, part of the U.S. Department of Energy, conducts research on technologies to help break down biomass into products for use at biofuel refineries. The office also provides funds for developing biomass processing depots located near biofuel production sites.[11][12]
The USDA and Energy Department jointly run a program to fund research projects designed to improve feedstock production. This research focuses on how the genes, proteins, and molecules in feedstocks interact during production. Researchers then use this knowledge to grow feedstock that can use nutrients more efficiently and thus lead to increased feedstock production.[13]
See also
Footnotes
- ↑ Wisconsin State Energy Office, “A Renewable Energy and Bioeconomy Dictionary,” accessed January 30, 2014
- ↑ How Stuff Workds, "Biofuels vs. Fossil Fuels," accessed December 16, 2016
- ↑ Congressional Research Service, "Renewable Fuel Standard: Overview and Issues," accessed March 14, 2013
- ↑ U.S. Government Printing Office, "Energy Independence and Security Act of 2007," accessed December 16, 2016
- ↑ University of Illinois, "Ethanol: What Is It?" accessed December 16, 2016
- ↑ BTU is a unit of measure for energy equivalent to the amount of energy used to raise the temperature of a pound of water one degree Fahrenheit.
- ↑ U.S. Energy Information Administration, "Table 10.3 Fuel Ethanol Overview," accessed December 16, 2016
- ↑ U.S. Department of Energy, "Biodiesel Production and Distribution," accessed December 16, 2016
- ↑ Biodiesel, "Biodiesel Basics," accessed December 16, 2016
- ↑ U.S. Energy Information Administration, "Table 3. U.S. inputs to biodiesel production," accessed December 16, 2016
- ↑ U.S. Department of Energy, "Biomass Feedstocks," accessed April 1, 2015
- ↑ U.S. Department of Energy, "Biomass Supply," accessed April 1, 2015
- ↑ U.S. Department of Energy, "Plant Feedstock Genomics for Bioenergy," accessed December 16, 2016
