Volatile liquid spills evaporation

Clear, colorless to pale yellow-brown, watery, volatile liquid with a sweet, irritating or pungent odor resembling peach pits, onions, or garlic. Evaporates quickly when spilled. Turns dark on exposure to air. Odor threshold concentrations of 1.6 and 8.8 ppmv were reported by Stalker (1973) and Nagata and Takeuchi (1990), respectively. 

The primary parameters affecting entrainment and evaporation are solar radiation, ambient temperature, storage or process temperature and pressure, liquid spill surface area, wind speed and the properties of the spilled material (such as vapor pressure, surface tension, and viscosity). Suppressing volatility by reducing containment temperature and constraining pool size or exposed surface area via a dike or berm are effective postmitigation approaches and are discussed in Chapters 3 and 5. 

The flash point of an oil is the temperature at which the liquid gives off sufficient vapours to ignite upon exposure to an open flame. A liquid is considered to be flammable if its flash point is less than 60°C. There is a broad range of flash points for oils and petroleum products, many of which are considered flammable, especially when fresh. Gasoline, which is flammable under all ambient conditions, poses a serious hazard when spilled. Many fresh crude oils have an abundance of volatile components and may be flammable for as long as 1 day until the more volatile components have evaporated. On the other hand, Bunker C and heavy crude oils generally are not flammable when spilled. 

A. Compound Volatility. One is sometimes required or requested to evaluate the potential irritancy of a liquid that has a boiling point between room temperature and the body temperature of the test animal. As a result, the liquid portion of the material will evaporate off before the end of the testing period. There is no real way around the problem one can only make clear in the report on the test that the traditional test requirements were not met, though an evaluation of potential irritant hazard was probably achieved (for the liquid phase would also have evaporated from a human that it was spilled on). 

Reijnhart et al. (1980) analyzed mass transfer from spills of volatile, single component, liquids into turbulent air streams. As the temperature increases the high flux correction factors become significant due to the increased mass transfer rates. Reconcile the analysis of Reijnhart et al. with the material presented in Chapter 10. Attempt to simulate their experimental results for the evaporation of toluene into air. Note that for spills of multicomponent liquid mixtures, the analysis of Chapter 10 really comes into its own. 

The hazards of a spill of a volatile toxic or flammable liquid are primarily dependent on the size of the spin, in terms of its diameter or area, since the rate of evaporation depends primarily on the surface area. If the spill is into a dike or curbed area, the area of the spill that is exposed to evaporation is the area of the confinement. If the spill is onto a surface without confinement, the spill area is related to the viscosity and is limited by the rate of evaporation at the outside edge of the spill. 

All of the 23 plasticizers in Table 18.1 occur as viscous or oily liquids that range from colorless to an amber color. If these liquids were spilled on soil or sediments, a portion of the liquid could volatilize into the air, depending on the specific compound, but most of the 23 plasticizers have vapor pressures that are less than 10 mm Hg at 25°C (Table 18.13). The vapor pressures of nine of the compounds have not been measured. For these plasticizers, vapor pressures were estimated using the Fragment Constant Method. As noted earlier, most of these chemicals will also be adsorbed by soil and sediments which would reduce the extent of volatiUzation. The rate of volatilization of plasticizers from soil has not been measured. For the purpose of illustration, the Dow Method was applied to estimate the half-life of each plasticizer if it was spilled on the surface of a dry soil. The Dow Method is a simple relationship that was derived for the evaporation of pesticides from bare soil ... 

The volatile analytes in a gas sample may have always been there, like argon in air, or they may migrate there from some other source, like air pollutants from the evaporation of spilled gasoline. The controlled analysis of vapors that have migrated into an atmosphere from some solid or liquid source forms the basis of static headspace analysis. 

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