E85 fuel

The nation s first E85 (85% ethanol) fueling station opened in La Habra, CA in 1990, operated by the California Renewable Fuels Council. 

Bioethanol is the largest biofuel today and is used in low 5%—10% blends with gasoline (E5, E10), but also as E85 in flexible-fuel vehicles. Conventional production is a well known process, based on the enzymatic conversion of starchy biomass (cereals) into sugars, and fermentation of 6-carbon sugars with final distillation of ethanol to fuel grade. 

For the calculation of WTW energy requirements and GHG emissions we have made the simplification that the fuel consumption of a vehicle fuelled with ethanol (e.g., E85) is the same as that of a vehicle fuelled with pure gasoline. Methanol is used in fuel cell vehicles with on-board fuel processors. Table 7.2 shows the properties of different transportation fuels. 

Alternative fuels Liquefied petroleum gases (LPG), Ethanol, 85% (E85), Ethanol, 95% (E95), Methanol, 85% (M85), Methanol, neat (MlOO), Compressed natural gas (CNG), Liquefied natural gas (LNG), Biodiesel (BD), Hydrogen, and Electricity... 

Cold weather starting for ethanol fuels is poor unless blended with gasoline or some other starting fluid such as dimethyl ether or isopentane. The minimum starting temperature for neat ethanol fuel is about 60°F (15.6°F). In E95, E85, and E10 blends, the starting problems are minimized. 

Because CNG is primarily methane, it is expected to have relatively low reactivity, with the small amounts of reactive impurities such as small olefins and alkanes being responsible for most of its reactivity (see Table 16.14). Emissions of CO are smaller than from gasoline-powered vehicles, while the effect on NOx emissions is not clear (National Research Council, 1991). As seen in Tables 16.10 and 16.11, CNG shows the highest promise for low-reactivity exhaust emissions, and this appears to be the case for its use in real vehicles (Gabele, 1995). Figure 16.40, for example, shows the estimated ozone production per mile traveled for a vehicle fueled on CNG compared to vehicles fueled on reformulated gasoline (RFG) or the alcohol fuels M85 or E85 (vide infra). These measurements and estimates based on them include the contributions from both exhaust (including CO) and evaporative emissions (Black et al., 1998). Clearly, the reactivity of the CNG-powered vehicle emissions was substantially smaller than for the other vehicle-fuel combinations. 

FIGURE 16.40 Calculated ozone production per vehicle mile traveled for various car-fuel combinations. RFG = reformulated gasoline M85 = 85% methanol, 15% gasoline E85 = 85% ethanol, 15% gasoline CNG = compressed natural gas (adapted from Black et al., 1998). 

The emission characteristics of E85 vehicles are not as well documented as for M85 vehicles however, Ford tested E85 in their 1996 model Taurus flexible fuel vehicle and found essentially no difference in tailpipe emissions compared to using the standard emissions testing gasoline (Indolene). In this test, the engine-out emissions of HC and NOx were lower than for gasoline, but ethanol s lower exhaust gas temperatures were believed to decrease catalyst efficiency slightly... 

The maintenance requirements of E85 vehicles should be essentially the same as for M85 vehicles, and very similar to their conventional petroleum fuel vehicle counterparts. The oil specified for E85 vehicles has a special additive package and is currently expensive (approximately 3.00 per quart) because of low volume production. In high volume production E85 engine oil should be no more expensive than gasoline engine oil. 

Benson, J.D., et al., Emissions with E85 and Gasolines in Flexible/ Variable Fuel Vehicles—The Auto/Oil Air Quality Improvement Research Program, SAE Paper No. 952508, Society of Automotive Engineers, Warrendale, Pa., 1995. 

Table 2-3. M85 and E85 Properties Compared to Gasoline Fuel Property M85 E85a Gasolineb...

Little work has been done to measure the octane value of M85 and E85, but what has been done has shown their octane values to be only slightly degraded from pure methanol and ethanol [2.8], The American Society for Testing and Materials (ASTM) has developed specifications (D 5797 and D 5798) for fuel methanol and fuel ethanol [2.9,2.10]. Both specifications define three classes of... 

Ethanol is widely acknowledged to be less aggressive toward metals and elastomers than methanol, but little research and development has been devoted to the specific problems posed by ethanol. Ethanol typically has more water in it than methanol (an artifact of production) which may affect solubility of contaminants and corrosion potential. One ethanol contaminant that can arise from production is acetic acid, which is water-soluble and will corrode some automotive fuel system components. For instance, General Motors found that E85 caused more corrosion in fuel pumps than M85, presumably because of a higher level of dissolved contaminants [3.2]. Since much more development has been devoted to compatibility with methanol fuels, the general approach for ethanol has been to use materials developed for methanol, even though they may be over-engineered. ... 

FFV Flexible fuel vehicle—vehicles able to operate on gasoline, M85 or E85, or any mixture of the two gasoline and alcohol fuels. 

Yet despite the millions of vehicles on the road that can run on E85 and billions of dollars in federal subsidies to participating refiners, many oil companies seem unenthusiastic about the adoption of the higher ethanol mix. E85 requires separate gasoline pumps, trucks and storage tanks, as well as substantial cost to the oil companies (the pumps can alone cost about 200,000 per gas station to install). Many drivers who have tried filling up with E85 once revert to regular unleaded when they find as much as a 25% loss in fuel economy when burning the blend. 

The ethanol portion of motor fuels (such as E10 and E85) consumed by the transportation sector. 

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