Vapor pressure diesel fuel

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. 

Fuel volatility is an extremely important factor related to fuel combustion and burning efficiency. Evaporation, vaporization, and vapor pressure of fuel can all be reduced in cold environments. Poor startability and warmup of gasoline and diesel engines can be directly related to fuel volatility. Also, cold kerosene will not vaporize and bum as efficiently in wick-fed systems. 

Vehicle LPG storage tanks are cylindrical with rounded ends and are capable of holding fuel at pressures of 240 to 250 psig. The tanks are much stronger than those used to hold conventional liquid fuels, but less sophisticated than CNG storage tanks. Carbon steel or aluminum can be used for tank construction. Because propane can dissolve plasticizers used in elastomer production, only propane-resistant elastomers such as neoprene, nitrile, or Teflon should be used. Except for the need for a gas-tight connection, LPG can be dispensed in the same manner as gasoline or diesel fuel. To ensure that adequate vapor space is available for gas expansion, automatic limiters are incorporated to maintain an 80% maximum fill rate. 

Biodiesel can be stored in the steel or fiberglass tanks currently used for diesel fuel. All the regulations for above-ground and underground diesel fuel tanks apply to tanks holding biodiesel. Conservation vents are not required since the vapor pressure of biodiesel is very low, as it is for diesel fuel. 

Specific codes or regulations for vehicular storage and dispensing systems for alcohol fuels do not exist. Alcohols are flammable liquids which are covered in NFPA 30, Flammable and Combustible Liquids Code [5.2], Gasoline is included under NFPA 30 as a Class IA flammable liquid, while diesel fuel is included as a combustible liquid. When alcohols are used as fuel for vehicles, they almost always have some gasoline or high vapor pressure hydrocarbons in them which... 

Diesel fuel starts to be atomized (at B) at high pressure in the combustion chamber where it is mixed with compressed air. The mixture obtained is very heterogeneous, containing droplets of unvaporized diesel fuel, in addition to zones which are rich, or lean in vaporized diesel fuel. The injection of diesel fuel continues up to point D. 

GasoUne is a mixture of hydrocarbons (primarily alkanes) that contain 5 to 12 carbon atoms per molecule. Diesel fuel is a similar mixture, except the molecules contain 12 to 16 carbon atoms. The hot CO2 and water vapor generated during combustion in an internal combustion engine have a much greater volume than the air and fuel mixture. It is this sudden increase in gaseous volume and pressure that pushes the pistons and delivers power to the crankshaft. 

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