Blended fuels

In automotive and aerospace end uses, the apphcations ate also often electrical. Polysulfones do not have as good solvent resistance as poly(phenylene sulfide). They perform well in hydrocarbons like gasoline and oil, or in antifreeze, but ate attacked by the alcohol-blend fuel mixtures. This may limit their under-the-hood apphcations. 

Both the dipolymers and terpolymers have excellent resistance to hydrocarbons found m petroleum-based fuels and lubricants The 69 5% F terpolymer resists swellmg m blended fuels that contain metlianol and can be used in contact with certain phosphate ester-based hydraulic fluids Terpolymers are preferred for contact with aromatic solvents, although either type performs well in higher alcohols VDF-based elastomers dissolve m polar aprotic solvents such as ketones, esters, amides, and certam ethers These elastomers are therefore not suitable for contact with fluids that contain substantial amounts of these solvents because of excessive swell and consequent loss of mechanical properties... 

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 number of processes exist which can be utilized to improve the quality of refined and blended fuels. These processes are often an essential part of ensuring that finished fuels are free of contamination and meet required specifications. Some of the common fuel constituents which can cause fuel storage, handling, and performance problems are outlined in TABLE 2-6. 

Within the closed system of a refinery, rust, metal salts, and catalyst fines exist. While being refined, processed, and blended, fuels may pick up some of these... 

Blend fuel with kerosene or 1 distillate to dilute the effect of wax. 

The equipment used to store blend fuels and inject additives into fuel can be designed to fit a specific application. The equipment selection is based upon several factors including the characteristics of the fuel or additive, operating specifications, and various regulatory issues. 

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. 

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). 

Figure 14. Road Antiknock Ratings of Conventional Fuel and Specially Blended Fuel...

In this program, two types of fuel oil blends were combusted. One type of blend was derived only from primary liquefaction products, VGO and solvent, having a nominal boiling range of 350 to 1000°F and are referred to as 350-1000°F blends. Fuel oils were also blended by adding coker liquids, containing 1000°F+ material, to the 350-1000°F blends and are referred to as 350°F+ blends. 

The automobile engine s drive train sets the specifications for gasoline. Notably, as automobile manufacturers design more sophisticated engines, in response refiners must adjust their operation to refine and blend fuels that are compatible with newer engines. 

The more severe conditions of the motor method have a greater influence on commercial blends than they do on the reference fuels. Thus, a motor octane number (MON) of a commercial blend often has a lower research octane number (RON). Consequently, blended fuels use an arithmetic average of both ratings—MON and RON—and can be abbreviated as (R + M)/2. 

Figure 11 displays the energy consumption characteristics of the clear and blended fuels on a thermal efficiency basis. From this information it is apparent that, at equivalent operating conditions, there is essentially no difference in engine efficiency caused by the addition of methanol. The figures also indicate that if the engine can be operated at greater (leaner) equivalence ratios, some increases in thermal efficiency can be expected. 

On a liquid fuel basis, these feedstocks would equal about 3.7 billion gallons of diesel fuel, about 13% of the 28 billion gallons of diesel fuel consumed in the United States for transportation in 1996. If biodiesel was blended with petroleum diesel fuel, e.g., 20% biodiesel and 80% petroleum (B20), the total supply of this blended fuel would be about 18.7 billion gallons, or 67% of U.S. annual diesel consumption. This example uses the total average supply of all crop oils, animal fats, and yellow grease as the available feedstock supply (182). 

All tests were performed using the same biomass fuel composed of 80 wt.% wood blended with 20 wt.% almond shells. Wood fuel was obtained from the fuel feed conveyors of an operating biomass power plant and was largely a mixture of Douglas fir and Ponderosa pine. The blended fuel material was milled and sieved through a 16 mesh (1 mm) screen. Before each test, the moisture content was determined by drying the fuel for 24 hours in an air oven at 1Q3 C. The moisture content ranged from 9.1 to 9.4 wt.% wet basis. Properties of the fuel are listed in Table 1. 

RPB/coal, a blend fuel mixed m the ratios of 15 85 bark coal (thermal input), equivalent to 19 81 bark coal on a mass basis. The bark was from the same sawmill as above and the coal was a sub-bituminous coal (below) ... 

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