by Brian J. Donovan, CEO Renergie, Inc.
[This opinion piece originally appeared in the Field-to-Pump blog, published by Renergie, Inc.]
Use of Hydrous Ethanol in Brazil
The oil price shocks of the 1970s led the Brazilian government to address the strain high prices were placing on its fragile economy. Brazil, the largest and most populous country in South America, was importing 80% of its oil and 40% of its foreign exchange was used to pay for that imported oil.
In 1975, General Ernesto Geisel, then-president of Brazil, ordered the country’s gasoline supply mixed with 10% ethanol. The level was raised to 25% over the next five years, which was intended to maintain a constant Brazilian gasoline supply for an ever-increasing demand. The government assisted the shift by giving sugar companies subsidized loans to build ethanol plants, as well as guaranteeing prices for their ethanol products. Already the world’s biggest producer and exporter of sugar, farmers reaped the benefits of this new demand.
The 1979 Iranian crisis and related oil price shock accelerated Brazil’s conversion of its gasoline supply and automobile fleet. Under the Proalcool Program, sugar companies were ordered to increase production and the state-run oil company, Petrobras, was required to make álcool (ethanol) available at its fuel stations. The growth in hydrous ethanol, which uses a blend of 94-95% ethanol to 5-6% water, rapidly increased during the 1980s, with consumption peaking in 1989.
Automobile manufacturers were given tax breaks to produce cars that ran on hydrous ethanol, and, by 1980, every automobile company in Brazil was following this lead. By the mid-1980s, three quarters of the cars manufactured in Brazil were capable of running on sugarcane-based hydrous ethanol.
However, the drop in oil prices throughout the 1980s and 1990s made it uneconomic for the Brazilian government to continue its ethanol program. Both production and consumption of ethanol were basically flat for much of the mid-1980s to the mid-1990s. After 1995, both production and consumption of hydrous ethanol began falling quickly. The Brazilian government’s dedication to the ethanol industry declined and incentives given by the government wore off, causing hydrous ethanol-fueled vehicle production to decline in the late 1980s to early 1990s. As oil prices decreased in the 1990s, the consumer acceptance of hydrous ethanol fueled cars greatly decreased and purchases of gasoline fueled automobiles returned to previous levels. The production and consumption of hydrous ethanol fuel followed an expected pattern.
The second wave of ethanol fuel production and consumption in the Brazilian market began in the 1990s when the use of anhydrous ethanol started to rise. Consumption of anhydrous ethanol has grown steadily since the 1990s, peaking in 2003.
The start of the new millennium brought with it increased oil prices, which in turn sparked a resurgence of Brazil’s drive toward energy independence, including a revival of its ethanol program. Although it previously used a hydrous ethanol blend, Brazil shifted toward the aforementioned anhydrous ethanol, which is used in a ratio of ethanol to gasoline of 20-24:80-76.
Brazil introduced its current generation of ethanol-powered cars in 2003, the same year in which anhydrous ethanol consumption peaked. Named flex-fuel vehicles (FFVs), these automobiles run on gasoline, ethanol, or any blend of the two. When the car is filled at the pump, an internal system analyses the mix of the two fuel types and adjusts accordingly. The first such vehicles were introduced by Volkswagen in 2003, and by 2004, they accounted for more than 17% of the Brazilian auto market. In 2005, their sales increased even further, accounting for approximately 54% of all new car sales.
Before the introduction of the flex-fuel car in Brazil in 2003, cars running on ethanol fuel were primarily using pure ethanol or hydrous ethanol blends.
In Brazil, there are currently two fuel types available at the fuel station for passenger vehicles: E100 (AEHC) that is the derived from a simple distillation process and has about 4.9% water content in it and Gasoline C, or E25, which is a mixture of 75% Gasoline A and 25% in volume of anhydrous ethanol (AEAC) with a maximum of 0.4% of water. It is possible to use gasoline C made with hydrated ethanol (AEHC) with minimum risk of phase separation due to Brazilian climate conditions.
The Brazilian experience shows that the presence of small (<10%) amounts of water in the fuel does not in itself cause a greater tendency to misfire in spark ignition engines than a proportionate leaning of the fuel/air mixture would do, provided that the vapor pressure of the hydrated ethanol at the ambient temperature is high enough. Experiments have even shown that the evaporation of the water in the intake manifold acts as a charge air cooling, which improves the volumetric efficiency and thereby the overall efficiency of the engine.
One of the most obvious downsides is, of course, that the heating value of water is zero and as such water is simply dead weight in the fuel tank. This clearly means that a vehicle running on water-free (anhydrous) ethanol will still (even with the better volumetric efficiency) have a higher mileage per gallon than one running on hydrous ethanol. However, since the cost of the hydrous ethanol is significantly lower, hydrous ethanol will provide a lower cost per mile travelled, assuming the processing cost savings is passed on to the consumer.
Use of Hydrous Ethanol in the United States
Hydrous ethanol has been used in the United States as a transportation fuel for at least one hundred years. The Model T Ford, which debuted in 1908, was originally designed to operate on alcohol. The Model T and Model A Fords were later designed to operate on either alcohol or gasoline or a blend of alcohol and gasoline. These were arguably the first flex-fuel vehicles.
During the early 1900s, a distillery was a standard piece of farm equipment. These distilleries made 192-proof alcohol for human consumption, lantern fuel and transportation fuel. The distilleries were referred to as “stills” and the alcohol became known during the Prohibition period as “moonshine.” This moonshine was hydrous ethanol. Rural America, especially southern rural America, has always used small farm distilleries to process hydrous ethanol for transportation fuel during times of severe oil shortages or high gasoline prices.
Since the 1973 oil crisis, a plethora of books and instruction manuals have been published in the US on the subject of how to build small stills to produce inexpensive 192-proof alcohol (hydrous ethanol) to be used to blend with gasoline in motor vehicles. Until fairly recently, these US motor vehicles were non-FFVs.
Current Legal Requirement for Use of Anhydrous Ethanol in the United States
40 CFR § 80.27 addresses controls and prohibitions on gasoline volatility. Pursuant to 40 CFR § 80.27(a)(2):
Prohibited activities in 1992 and beyond. During the 1992 and later high ozone seasons no person, including without limitation, no retailer or wholesale purchaser-consumer, and during the 1992 and later regulatory control periods, no refiner, importer, distributor, reseller, or carrier shall sell, offer for sale, dispense, supply, offer for supply, transport or introduce into commerce gasoline whose Reid vapor pressure exceeds the applicable standard. As used in this section and Sec. 80.28, “applicable standard” means:
- 9.0 psi for all designated volatility attainment areas; and
- The standard listed in this paragraph for the state and time period in which the gasoline is intended to be dispensed to motor vehicles for any designated volatility nonattainment area within such State or, if such area and time period cannot be determined, the standard listed in this paragraph that specifies the lowest Reid vapor pressure for the year in which the gasoline is sampled. Designated volatility attainment and designated volatility nonattainment areas and their exact boundaries are described in 40 CFR part 81, or such part as shall later be designated for that purpose. As used in this section and Sec. 80.27, “high ozone season” means the period from June 1 to September 15 of any calendar year and “regulatory control period” means the period from May 1 to September 15 of any calendar year.
40 CFR § 80.27(d) further provides for alcohol blends as follows:
Special provisions for alcohol blends. (1) Any gasoline which meets the requirements of paragraph (d)(2) of this section shall not be in violation of this section if its Reid vapor pressure does not exceed the applicable standard in paragraph (a) of this section by more than one pound per square inch (1.0 psi). (2) In order to qualify for the special regulatory treatment specified in paragraph (d)(1) of this section, gasoline must contain denatured, anhydrous ethanol. The concentration of the ethanol, excluding the required denaturing agent, must be at least 9% and no more than 10% (by volume) of the gasoline. The ethanol content of the gasoline shall be determined by use of one of the testing methodologies specified in appendix F to this part. The maximum ethanol content of gasoline shall not exceed any applicable waiver conditions under section 211(f)(4) of the Clean Air Act.
US Environmental Protection Agency Grants Testing Waiver
In February, 2009, the US EPA granted Renergie, Inc. a first-of-its-kind waiver for the purpose of testing hydrous E10, E20, E30 & E85 ethanol blends in non-flex-fuel vehicles and flex-fuel vehicles in the State of Louisiana. [Earlier GCC post.] Under this test program, Renergie will use variable blending pumps, not splash blending, to precisely dispense hydrous ethanol blends of E10, E20, E30, and E85 to test vehicles for the purpose of testing for blend optimization with respect to fuel economy, engine emissions, and vehicle drivability.
Anhydrous Ethanol vs. Hydrous Ethanol
Ethanol (C2H5OH), otherwise known as ethyl alcohol, alcohol, or grain spirit, is a clear, colorless, flammable oxygenated hydrocarbon with a boiling point of 78.5 °C in the anhydrous state. In transportation, ethanol is used as a vehicle fuel by itself (E100), blended with gasoline (E85), or as a gasoline octane enhancer and oxygenate (10 percent concentration).
Anhydrous ethanol means an ethyl alcohol that has a purity of at least ninety-nine percent, exclusive of added denaturants, that meets all the requirements of the American Society of Testing and Materials (ASTM) D4806, the standard specification for ethanol used as motor fuel.
Hydrous (or wet) ethanol is the most concentrated grade of ethanol that can be produced by simple distillation, without the further dehydration step necessary to produce anhydrous (or dry) ethanol. Hydrous ethanol (also sometimes known as azeotropic ethanol) typically ranges from 186 proof (93% ethanol, 7% water) to 192 proof (96% ethanol, 4% water).
Initial tests conducted in Europe have confirmed that hydrous ethanol can be blended effectively with gasoline without phase separation or other problems. An unmodified Volkswagen Golf 5 FSI was operated successfully on HE15 (15% hydrous ethanol blended with gasoline), meeting European exhaust emission standards in testing conducted by the Netherlands research organization TNO Automotive and by SGS Drive Technology Center of Austria.
In addition to confirming the effectiveness of hydrous ethanol for gasoline blending in actual vehicle trials, these initial tests have shown measurable increases in volumetric fuel economy, indicating higher thermodynamic efficiencies resulting from hydrous ethanol. This recently discovered phenomena for mid-level ethanol blends appears to be due to the benefits of oxygenation and heat of vaporization in conjunction with capitalizing on the change in chemical and physical properties which occur as a result of combining water, ethanol, and gasoline.
When appropriately combined in mid-level ethanol blends, the chemical reactions of these compounds optimize the efficiency at which internal combustion engines operate. For hydrous ethanol blends, this is accomplished primarily through the total heat of vaporization resulting from combining ethanol and water. Essentially, the lower energy content of hydrous ethanol is counteracted by increasing engine performance due to higher heat of vaporization of ethanol and water in comparison with gasoline and anhydrous blends.
Hydrous ethanol blends (oxygenated hydrocarbons) lower engine operating temperatures due to cooling of intake fuel mixture with 3-6% more water and increasing heat of vaporization when compared to anhydrous ethanol. The result is more efficient combustion, cooler running engines, lower exhaust temperatures, and increased longevity of engine life. The water contained in hydrous ethanol blends also reduces NOx emissions.
In addition to the effects of higher water content in hydrous ethanol, ethanol increases compression ratios and decreases engine knocking (detonation). Essentially, both water and ethanol increase the octane level of the fuel mixture. The octane number is a measure of the resistance of a fuel to auto-ignition. It is also defined as a measure of anti-knock performance of a gasoline or gasoline component such as hydrous ethanol. Higher octane levels contribute to enhancing the thermodynamic efficiency of combustion engines, which subsequently increases fuel efficiency. The increase in total engine efficiency results in optimizing fuel efficiency for both ethanol and gasoline.
In addition to the strong hydrogen bonds contained in water molecules, the polarity of the OH groups contained in ethanol molecules can form hydrogen bridges causing relatively strong attractive forces between molecules in liquid phases. Upon vaporization of hydrous ethanol as a fuel, the distance between the water and ethanol molecules increase such that molecular interactions including physical properties are disrupted. This process accumulates a certain amount of latent (stored) energy.
During combustion of these vapors, this explains why the heat of vaporization of hydrous ethanol blends is so much higher than that of regular gasoline components and non-alcohol oxygenates like methyl tertiary butyl ether (MTBE) which do not contain OH groups (non-alcohols). High heat of vaporization values are typical for water and alcohols including hydrous ethanol and hydrous ethanol blends (oxygenated hydrocarbons).
According to Baylor University, “as far as safety and performance is concerned, hydrous ethanol is a slightly better fuel [than anhydrous ethanol] in every respect (except specific fuel consumption since water does not provide any caloric content). Small quantities of water absorbed in the fuel result in a slight increase in power caused by the higher latent heat of vaporization of the fuel.”
Previous assumptions held that ethanol’s lower energy content directly correlates with lower fuel economy for automobiles. Those assumptions were found to be incorrect. Instead, the new research strongly suggests that there is an “optimal blend level” of ethanol and gasoline—most likely E20 or E30—at which cars will get better mileage than predicted based strictly on the fuel’s per-gallon Btu content.
The 2007 flex-fuel Chevrolet Impala utilized in midlevel blends testing revealed a 15% increase in fuel efficiency using the Highway Fuel Economy Test (HWFET) for E20 in comparison with unleaded regular gasoline. For the same vehicle, the highway fuel economy was greater than calculated for all tested blends, with an especially high peak at E20. The new study, co-sponsored by the US Department of Energy (DOE) and the American Coalition for Ethanol (ACE), also found that mid-range ethanol blends reduce harmful tailpipe emissions.
Rapid expansion of the ethanol industry is creating global supply/demand issues. In some geographical areas, like the US for example, supply is outgrowing demand. This is having a negative effect on the price of ethanol for producers and sustainability of the ethanol industry.
Due to emissions and durability testing requirements, ethanol producers are having difficulty with assessing the economic and environmental impacts of mid-level anhydrous ethanol blends on current auto engines in order to increase blending rates and the RFS. In contrast to higher percentage anhydrous ethanol blends, HE15 and higher blends can be utilized in legacy vehicles (existing auto engines) as well as FFVs. Once parallel testing has been conducted for midlevel and E85/HE85 anhydrous and hydrous ethanol blends, further fuel efficiency and emissions testing may not be necessary. In addition to raising blending rates and the RFS, the high price of corn and competition between food and fuel is squeezing profit margins of ethanol producers, resulting in global inflation of fertilizers, and reducing food supplies for staple food products including rice, corn, potatoes and wheat. Hydrous ethanol blends could reduce some of this inflationary pressure by increasing efficiencies of production.
Current US FFVs are not designed to use either hydrous or anhydrous ethanol by itself, but rely on a blend of ethanol and gasoline to alleviate cold start problems. It should be noted that since the miscibility of liquids depends heavily on the ambient temperature, though not in a strictly linear way, it is unknown what the water tolerances would be at the lowest northern US winter temperatures.
However, a 3-6% increase in hydrous ethanol production accompanied by a decrease in energy costs, plus an increase in fuel efficiency, will help to increase ethanol sales and profit margins for ethanol producers. Existing gasoline pipelines will be able to utilize midlevel hydrous ethanol blends as a much more compatible blendstock. This will dramatically reduce transportation costs by allowing petro-refineries and blenders to leverage existing infrastructures for distribution of hydrous ethanol. New turbocharged engines designed for ethanol only, FFV, and ethanol hybrid vehicle technologies allow for utilizing hydrous ethanol in E85 and E100 fuels in conjunction with electric power to provide unprecedented power, fuel efficiency and emissions reductions. Such combinations can substantially reduce and eventually eliminate dependence on fossil fuels.
In summary, a transition from anhydrous to hydrous ethanol in the United States is expected to make a significant contribution to ethanol’s cost-competitiveness, fuel cycle net energy balance, and greenhouse gas emissions profile.
[Renergie was formed by Ms. Meaghan M. Donovan on 22 March 2006 for the purpose of raising capital to develop, construct, own and operate a network of ten ethanol plants in the parishes of the State of Louisiana which were devastated by hurricanes Katrina and Rita. Each ethanol plant will have a production capacity of five million gallons per year (5 MGY) of fuel-grade ethanol.]
Keuken, J. et al. (2008) Hydrous Ethanol for Gasoline Blending: New Science Promises Cost and Energy Savings, 17th International Symposium on Alcohol Fuels, 13-16 October 2008, Tiayuan, China.
Brewster, S.C., et. al., “The Effect of E100 Water Content on High Load Performance of a Spray Guide Direct Injection Boosted Engine”. SAE paper # 2007-01-2648