Ethanol blending

Value shown is for denatured ethanol. Neat ethanol blended at 10.0 vol % produces 3.7 wt % oxygen. 

Ethanol blends can also have an effect on NO emissions. Scattered data indicate that NO may increase as oxygenates are added to the fuel. 

Transportation fuels are the largest consumers of crude oil. Petroleum-based transportation fuels are responsible for 35 percent of greenhouse gas emissions m the United States. Only percent of transportation fuels comes from renewable nonpetro-leum-based sources, primarily from the use of corn-based ethanol blended with gasoline to make gasohol. Increased use of biofuels could lower some of the pollution caused by the use of transportatiou fuels. 

Demand for gasoline is 125 billion gals (473 billion 1) per year according to 1998 estimates. The Clean Air Act Amendment of 1990 mandates the use of oxygenated fuels such as ethanol blends with up to 3.5 percent oxygen by weight in gasoline (E-10 or... 

In 1997 a total 1.3 billion gals of ethanol fuel was produced in the United States. Proposed new low sulfur conventional gasoline standards could greatly increase the demand for ethanol since desulfurization may lower gasoline octane. Almost all fuel ethanol is used as gasohol, but some is used to make E-85 (85% ethanol and 15% gasoline). E-85 can be used in flexible-fuel vehicles (FFVs) which can operate on gasoline or ethanol blends of to 85 percent ethanol. 

Owing to this problem of phase separation, gasoline/ethanol blends should be not exposed to water during distribution or use in a vehicle. For this reason, they cannot be transported in pipelines, which sometimes contain water. This water sensitivity also means that extra care should be taken when gasoline/ethanol blends are used as a fuel for boat engines. 

Another volatility situation can occur if ethanol-blended fuel is mixed with hydrocarbon-only fuel in a vehicle fuel tank. This event is called commingling . In effect, the ethanol in the blend increases the vapor pressure of the hydrocarbon-only gasoline. The increase in vapor pressure is dependent on the ratio of the two components and the amount of ethanol in the blend. 

A critical safety issue of using diesel-ethanol blends relates to flashpoint and flammability. E-diesel blends containing 10-15% ethanol have the vapor pressure and flammability limits of ethanol. This means that ethanol concentrations in enclosed spaces such as fuel storage and vehicle fuel tanks are flammable over the temperature range 13-42 °C. Thus, there are higher risks of fire and explosion than with diesel fuel, or even gasoline. Other vehicle performance-related concerns are (a) a decreased maximum power (b) an increased incidence of fuel pump vapor lock and (c) a reduced fuel pump and fuel injector life due to the decreased lubricity of ethanol. 

A low 50% point improves cold weather starting and acceleration not valid for oxygenate blends, especially ethanol blends. 

The common grades of ethanol blended fuels available in the United States are briefly described. Similar grades are available in other countries. 

Since ethanol is a single, highly polar organic molecule, it can provide performance different from traditional nonpolar hydrocarbon fuels that contain numerous organic molecules. Because of this fact, handling, storage, use, and performance of ethanol and ethanol blended fuels can differ from conventional fuels. 

The Reid vapor pressure of gasoline increases moderately when ethanol is blended into fuel as an oxygenate. At a 10% ethanol blend volume, the vapor pressure of gasoline can increase by 0.5 to 1.0 psi. 

Overall, the use of ethanol blends is believed not to be effective in reducing ozone, but may actually increase it (Calvert et al., 1993 Dunker et al., 1996). 

Stump, F. D K. T. Knapp, and W. D. Ray, Influence of Ethanol-Blended Fuels on the Emissions from Three Pre-1985 Light-Duty Passenger Vehicles, J. Air Waste Manage. Assoc., 46, 1149-1161 (1996). 

Before pumping ethanol-blended gasoline Med., 0.11 0.04-0.55 22 Backer et al. (1997)... 

Storing and Handling Ethanol and Gasoline-Ethanol Blends at Distribution Terminals and Service Stations, API Recommended Practice 1626, April 1985 American Petroleum Institute 1220 L Street, N.W. 

To remedy this problem, in the mid-1980s, Minnesota converted its state ethanol incentive from a consumer-oriented excise tax exemption to a producer-oriented direct payment. Instead of reducing state gasoline taxes by a couple of pennies for a 10% ethanol blend, the state paid 20(2 /gal for ethanol produced within the state. To encourage the construction of... 

Nowadays a worldwide focus is on renewable fuels, and ethanol has been considered an interesting option to replace petroleum derivate gasoline. It has been reported that the United States, France, Switzerland, Australia, Canada, China, Russia, India, South Africa, and the European Community are considering gasoline ethanol blends as fuel options. Recently, Brazilian government funds have been awarded to laboratories in universities and research centers in different regions of the country, and a strict control of the physicochemical characteristics of the gasohol blend and hydrated fuel alcohol for combustion machines is necessary to prevent adulteration (1,2). 

For gasoline substitution major problems are not expected. Brazil has used ethanol blended with gasoline for years without problems and now ethanol engines are part of the normal production of the Brazilian car industry. Methanol is very... 

The three main American car manufacturers are planning to have half of their fleets run on ethanol blends, and the government is subsidizing ethanol production. On the other hand, little has been done about the distribution of ethanol. Ethanol is corrosive, there are no ethanol pipelines, and ethanol trucks and railcars are few 40,000 ethanol railcars are on backorder. Because of all these problems, in 2007, the price of corn ethanol collapsed from 3.60/ gal to 1.80/gal. 

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