Brazil vs. United States Ethanol Industries
Sugarcane Based Ethanol Production in Brazil
Brazil is the world's second largest producer of ethanol and the world's largest exporter. Brazil and the United States lead the world in global ethanol production, accounting for nearly 70% of the world's production. Brazil produces approximately 37% of the world's total ethanol production and 48% of the world's ethanol used as fuel.
Brazil is considered to have the world's first sustainable biofuels economy and the biofuels industry leader. Its sugarcane ethanol program is considered a model for other countries and is the most successful alternative fuel program to date. Brazil's ethanol program is sustainable in Brazil due to its advanced agri-industrial technology and its enormous amount of arable land. Brazil's 30-year-old ethanol fuel program is based on the most efficient agricultural technology for sugarcane cultivation in the world. It uses modern equipment and cheap sugarcane as feedstock. The residual cane-waste (bagass) is used to produce heat and power, which results in a very competitive price and a high-energy balance (output energy/input energy). This energy balance varies from 8.3 for the average conditions to 10.2 for best practice production.
Since 1976, the government made it mandatory to blend anhydrous ethanol with gasoline, fluctuating between 10-25% and requiring only minor adjustments to regular gasoline motors. The Brazilian car manufacturing industry (Chevrolet, Ford, Fiat, Peugeot, Renault, Volkswagen, Honda, Mitsubishi, Toyota, and Citroen) developed flexible-fuel vehicles (early 2000's) that can run on any proportion of gasoline (E10-E25 blend) and hydrous ethanol (E100). Availability of ethanol fuel was achieved through government mandates, allowing Brazil in 2008 to have approximately 35,000 filling stations throughout the country with at least one ethanol pump. The success of flex vehicles, together with the mandatory E25 blend throughout the country, have allowed ethanol fuel consumption in the country to achieve a 50% market share of the gasoline-powered fleet in early 2008. Considering diesel-powered vehicles, sugarcane ethanol represented 16.7% of the country's total energy consumption by the automotive sector in 2007.
Ethanol production in Brazil uses sugarcane as feedstock and is based on the use of the sucrose content of sugarcane. There were 378 ethanol plants operating in Brazil by July 2008, 126 dedicated to ethanol production and 252 producing both sugar and ethanol. There are an additional 15 plants dedicated exclusively to ethanol production. In 2009, another 15 to 20 plants are expected to come on line and 60% of this new production will be dedicated to ethanol and 40% to sugar. By the end of 2009, the total crushing capacity in Brazil will be approximately 585 million metric tons of sugarcane per year.
Ethanol production is concentrated in the Central and Southeast regions of the country with the state of Sao Paulo accounting for 60% of the country's ethanol production. Sugarcane is semi-perennial and is harvested five times over a 6-7 year period. The harvest season in southeastern Brazil goes from April to November.
For the 2008-09 harvest it is expected that 44% of Brazil's sugarcane will be use for sugar production, 55% will be used for ethanol, and 1% will be used for alcoholic beverages. It is estimated that 24.9 billion liters of ethanol will be produced in 2008-09 with most of the production being destined for internal consumption and only 4.2 billion liters for export of which 2.5 billion liters destined for the U.S. market. Approximately 3.5 million hectares of land is use to produce ethanol and 3.0 million hectares is used to produce sugar. Most of the new sugarcane production in Brazil is going into former pastureland. In 2008 Brazil has 276 million hectares of arable land, 72% used for pasture, 17% for grain crops, and 2.8% for sugarcane, meaning that ethanol is just requiring approximately 1.5% of all arable land in the country.
Sucrose extraction from sugarcane accounts for little more than 30% of the chemical energy stored in the mature plant; 35% is in the leaves and stem tips, which are left in the fields during harvest, and 35% are in the fibrous material (bagass) left over from pressing. Most of the industrial processing of sugarcane in Brazil is done through an integrated production chain, allowing sugar production, industrial ethanol production, and electricity generation from byproducts. The typical steps for large-scale production of sugar and ethanol include milling, electricity generation, fermentation, distillation of ethanol, and dehydration.
Milling and refining
Once harvested and transported to the plant the cane is washed chopped and shredded.The cane is then pressed to extract the juice that contains 10-15% sucrose.The fiber residue is called bagass.The bagass is used as boiler fuel and burned for electricity generation allowing the plant to be self-sufficient in energy and to generate electricity for the local power grid.The cane juice is treated with chemicals and filtered.Before evaporation, the juice is filtered again producing a fluid rich in organic compounds called vinasse. Evaporation produces syrup, which is then crystallized resulting in a mixture of clear crystals surrounded by molasses.A centrifuge is used to separate the sugar from the molasses.The crystals are washed by steam and dried by airflow.The crystals continue to be processed into different types of sugar.The molasses is then processed into ethanol
Fermentation, distillation and dehydration
Yeast is added to the molasses to begin fermentation. Fermentation last from 4-12 hours resulting in fermented wine containing 7-10% alcohol. The yeast is recovered from the wine using a centrifuge.The alcohol is separated from the solid components.Hydrated ethanol is recovered that may contain up to 4.9% water by volume. This hydrous ethanol is the fuel used by ethanol-only and flex vehicles. Further dehydration can produce anhydrous ethanol that is blended with gasoline. This additional processing adds approximately 14% to the cost of the fuel.
Electricity generation from bagass
Bagass is burnt to provide the energy required for the industrial part of the process. High-pressure boilers are use to increase efficiency and allow sugar mills to sell excess electricity to local utilities. By 2000 more than 50 million tons of bagass were being produced from 300 million tons of harvested sugarcane. Electricity generated from bagass reached 3.0 GW in 2007 and is expected to reach 12.2 GW by 2014. Sugarcane bagass cogeneration accounts for 3% of the total Brazilian energy matrix.
Corn Based Ethanol Production In The United States
Current interest in ethanol fuel in the United States mainly lies in bio-ethanol, produced from corn, but there has been considerable debate about how useful bio-ethanol will be in replacing fossil fuel in vehicles. Concerns relate to the large amount of arable land required for crops, as well as the energy and pollution balance for the whole cycle of ethanol production.
Ethanol currently constitutes only a small fraction of the United States fuel supply, but domestic capacity has more than doubled since 2001, to over 4.5 billion gallons per year. Most cars on the road today can run blends of up to 10% ethanol and automobile manufactures already produce vehicles designed to run on much higher ethanol blends. Flexible-fuel vehicles can use gasoline and ethanol blends ranging from pure gasoline up to 85% ethanol (E85).
Ethanol is renewable because it is primarily the result of conversion of the sun's energy into usable energy. The creation of ethanol starts with photosynthesis causing the feedstock such as corn, sugarcane, or switchgrass to grow. These feedstocks are then processed into ethanol. Ethanol in the U. S. is produced from the distillation of corn. There are currently about 180 corn-based ethanol plants in the U.S. with dozens more under construction or on the drawing boards. Approximately 30% of the total U.S. corn crop is used to produce ethanol. This equates to 3.5 billion bushels of corn out of a total production of approximately 12.5 billion bushels.
In the U.S. there are two main methods of producing ethanol from corn - wet and dry milling.
Wet milling facilities can make a variety of corn-based products such as sweeteners and gluten feed while dry milling facilities are dedicated solely to ethanol production. Most of the ethanol production facilities in the U.S. are wet mills.
The difference between the two systems is the initial treatment of the grain. In dry milling, the entire corn kernel or other starchy grain is first ground into flour called meal and processed without separating out the various component parts of the grain. In wet milling, the grain is first soaked to facilitate the separation of the grain into its many component parts.
The corn kernel is ground into flour called meal. The meal is slurred with water to form a mash. Enzymes are added to the mash to convert the starch to dextrose, a simple sugar. Ammonia is added for pH control and as a nutrient for the yeast. The mash is processed in a high-temperature cooker to reduce bacterial levels ahead of fermentation. The mash is cooled and transferred to fermenters where yeast is added and the conversion of sugar to ethanol and carbon dioxide begins. Fermentation generally takes 40-50 hours. After fermentation, the resulting "beer" is transferred to distillation columns where the ethanol is separated from the remaining "stillage". The ethanol is concentrated to 190 proof. The anhydrous ethanol is then blended with 5% gasoline to render it undrinkable and thus not subject to beverage alcohol tax. It is then ready for shipment to gasoline terminals or retailers. The remaining solubles and course grain is concentrated and sold as distiller's grains, which is a high quality, nutritious livestock feed. The carbon dioxide released during fermentation is captured and sold for use in carbonating soft drinks and beverages.
In wet milling, the grain is soaked or "steeped" in water and dilute sulfurous acid for 24 to 48 hours. This separates the gain into its many component parts. The corn slurry is processed through a series of grinders to separate the corn germ. Corn oil is then extracted from the germ. The remaining fiber, gluten and starch components are further segregated. The fiber and steeping liquid are concentrated and sold as corn gluten feed to the livestock industry. Heavy steep water is also sold by itself as a feed ingredient and is used as a component in Ice Ban, an environmental friendly alternative to salt for removing ice from roads. The gluten component (protein) is filtered and dried to produce corn gluten meal, a popular feed ingredient for poultry. The starch and any remaining water from the mash can then be processed in one of three ways: Fermented into ethanol, dried and sold as dried or modified corn starch, or processed into corn syrup. The fermentation process for ethanol is very similar to the dry mill process. Approximately 2.65 gallons of ethanol can be produced from a bushel of corn in existing wet mill facilities. Approximately 2,75 gallons of ethanol can be produced from a bushel of corn using dry milling. A ton of U.S. corn can yield approximately 100 gallons of ethanol. A ton of sugar beets yields 25 gallons. A ton of Brazilian sugarcane yields 20 gallons.