ethanol

The compatibility of elastomeric materials used in fuel storage and dispensing applications was determined for test fuels
representing neat gasoline and gasoline blends containing 10 and 17 vol.% ethanol, and 16 and 24 vol.% isobutanol. The
actual test fuel chemistries were based on the aggressive formulations described in SAE J1681 for oxygenated gasoline.
Elastomer specimens of fluorocarbon, fluorosilicone, acrylonitrile rubber (NBR), polyurethane, neoprene, styrene
butadiene rubber (SBR) and silicone were exposed to the test fuels for 4 weeks at 60°C. After measuring the wetted
volume and hardness, the specimens were dried for 20 hours at 60°C and then remeasured for volume and hardness.
Dynamic mechanical analysis (DMA) was also performed to determine the glass transition temperature (Tg).
Comparison to the original values showed that all elastomer materials experienced volume expansion and softening when
wetted by the test fuels. The fluorocarbons underwent the least amount of swelling (100%). The level of swelling for each elastomer was higher for the test
fuels containing the alcohol additions. In general, ethanol produced slightly higher swell than the oxygen equivalent level of
isobutanol. When dried, the fluorocarbon specimens were slightly swollen (relative to the baseline values) due to fuel
retention. The NBRs and neoprene exhibited shrinkage and embrittlement associated with the extraction of plasticizers.
SBR also experienced shrinkage (after drying) but its hardness returned to the baseline value. The dried volumes (and
hardness values) of the silicone, SBR and fluorosilicone rubbers closely matched their original values, but the
polyurethane specimen showed degradation with exposure to the test fuels containing ethanol or isobutanol. The DMA
results showed that the test fuels effectively decreased Tg for the fluorocarbons, but increased Tg for the NBR materials.
The Tg values other elastomers were not affected by the test fuels.

The compatibility of plastic materials used in fuel storage and dispensing applications was determined for test fuels representing gasoline blended with 25 vol.% ethanol and gasoline blended with 16 and 24 vol.% isobutanol. Plastic materials included those used in flexible plastic piping and fiberglass resins. Other commonly used plastic materials were also evaluated. The plastic specimens were exposed to Fuel C, CE25a, CiBu16a, and CiBu24a for 16 weeks at 60oC. After measuring the wetted volume and hardness, the specimens were dried for 65 hours at 60oC and then remeasured for volume and hardness. Dynamic mechanical analysis (DMA) was also measured on the dried specimens.
The plastic materials used as permeation barriers exhibited the least amount of properly change when exposed to the test fuels. The performance of nylon was highly dependent on the grade; of the four nylons evaluated, Nylon 6 and Nylon 6,6 showed the lowest property change following exposure to Fuel C, CiBu16a and CiBu24s, but swelled over 7% when exposed to CE25a. Acetal and polybutylene terephthalate (PBT) swelled around 5% with exposure to the test fuels, while high density polyethylene (HDPE) swelled around 10% for each test fuel. The remaining thermoplastics swelled to higher values and in the case of polypropylene, dissolution occurred with exposure to CE25a. The fiberglass resins experience more swelling in CE25a that with the Fuel C or the two isobutanol blends. In general, the plastics exhibited a positive volume change when dried, which was attributed to fuel retention. In addition CE25a produced a higher degree of property change than the other test fuels.
 

This article summarises the compatibility of six elastomers – used in fuel
storage and delivery systems – with test fuels representing gasoline blended
with up to 85% ethanol. Individual coupons were exposed to test fuels for four
weeks to achieve saturation. The change in volume and hardness, when wetted
and after drying, were measured and compared with the original condition.

A new addition to the growing biofuels resources list at AgMRC is a cellulosic ethanol feasibility template developed by agricultural economists at Oklahoma State University (OSU). The purpose of the spreadsheet-based template is to give users the opportunity to assess the economics of a commercial-scale plant using enzymatic hydrolysis methods to process cellulosic materials into ethanol. The OSU Cellulosic Ethanol Feasibility Template can be downloaded and modified by the user to mimic the basic operating parameters of a proposed ethanol plant under a variety of production conditions.

The Energy Independence and Security Act (EISA) of 2007 established specific targets for the production of biofuel in the United States. Until advanced technologies become commercially viable, meeting these targets will increase demand for traditional agricultural commodities used to produce ethanol, resulting in land-use, production, and price changes throughout the farm sector. This report summarizes the estimated effects of meeting the EISA targets for 2015 on regional agricultural production and the environment. Meeting EISA targets for ethanol production is estimated to expand U.S. cropped acreage by nearly 5 million acres by 2015, an increase of 1.6 percent over what would otherwise be expected. Much of the growth comes from corn acreage, which increases by 3.5 percent over baseline projections. Water quality and soil carbon will also be affected, in some cases by greater percentages than suggested by changes in the amount of cropped land. The economic and environmental implications of displacing a portion of corn ethanol production with ethanol produced from crop residues are also estimated.

Ethanol use in the U.S. rose sharply in recent years due to public policy and a spike in petroleum prices, and remains high. Public support for ethanol includes mandated minimum levels of use nationwide. However, rather little is known about consumer demand for ethanol and much less about demand by type of blend and ethanol source. We used trial survey data and conjoint analysis to overcome the lack of historical data on consumers’ preferences for ethanol blend fuels. Preliminary findings based on responses from vehicle drivers in Missouri suggest that price is the primary factor behind fuel preferences. The disclosure of ethanol originated from woody feedstocks had a significant effect on preferences ceteris paribus. Ethanol blends of 20 percent had a negatively non-significant statistical effect compared to no-ethanol fuels or those with a 10 percent content. These findings will be tested using different models expanded to a nationwide pool of motor vehicle drivers.

This paper introduces a spatial bioeconomic model for study of potential cellulosic biomass supply at regional scale. By modeling the profitability of alternative crop production practices, it captures the opportunity cost of replacing current crops by cellulosic biomass crops. The model draws upon biophysical crop input-output coefficients, price and cost data, and spatial transportation costs in the context of profit maximization theory. Yields are simulated using temperature, precipitation and soil quality data with various commercial crops and potential new cellulosic biomass crops. Three types of alternative crop management scenarios are simulated by varying crop rotation, fertilization and tillage. The cost of transporting biomass to a specific demand location is obtained using road distances and bulk shipping costs from geographic information systems. The spatial mathematical programming model predicts the supply of biomass and implied environmental consequences for a landscape managed by representative, profit maximizing farmers. The model was applied and validated for simulation of cellulosic biomass supply in a 9-county region of southern Michigan. Results for 74 cropping systems simulated across 39 sub-watersheds show that crop residues are the first types of biomass to be supplied. Corn stover and wheat straw supply start at $21/Mg and $27/Mg delivered prices. Perennial bioenergy crops become profitable to produce when the delivered biomass price reaches $46/Mg for switchgrass, $118/Mg for grass mixes and $154/Mg for Miscanthus giganteus. The predicted effect of the USDA Biomass Conversion Assistance Program is to sharply reduce the minimum biomass price at which miscanthus would become profitable to supply. Compared to conventional crop production practices in the area, the EPIC-simulated environmental outcomes with crop residue removal include increased greenhouse gas emissions and reduced water quality through increased nutrient loss. By contrast, perennial cellulosic biomass crops reduced greenhouse gas emissions and improved water quality compared to current commercial cropping systems.

Traffic flows in the U.S. have been affected by the substantial increase and, as of January 2009, decrease in biofuel production and use. This paper considers a framework to study the effect on grain transportation flows of the 2005 Energy Act and subsequent legislation, which mandated higher production levels of biofuels, e.g. ethanol and biodiesels. Future research will incorporate changes due to the recent economic slowdown.

This article addresses development of the Illinois ethanol industry through the period 2007-2022, responding to the ethanol production mandates of the Renewable Fuel Standard by the U.S. Environmental Protection Agency. The planning for corn-based and cellulosic ethanol production requires integrated decisions on transportation, plant location, and capacity. The objective is to minimize the total system costs for transportation and processing of biomass, transportation of ethanol from refineries to the blending terminals and demand destinations, capital investment in refineries, and by-product credits. A multi-year transshipment and facility location model is presented to determine the optimal size and time to build each plant in the system, the amount of raw material processed by individual plants, and the distribution of bioenergy crops and ethanol.

This paper examines the possibilities of breaking into the cellulosic ethanol market in south Louisiana via strategic feedstock choices and the leveraging of the area’s competitive advantages. A small plant strategy is devised whereby the first-mover problem might be solved, and several scenarios are tested using Net Present Value analysis.