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phase to the concentration of the constilucnt in the dissolved phase is <br /> constant That is <br /> Pa = Hay-, <br /> where: <br /> Pa = partial pressure of constituent a in aur (atm) <br /> Ha = Henry's law constant (atm) <br /> Xa = Solution concentration of constituent (mole fraction) <br /> Henry's law constants for several constituents commonly found in <br /> petroleum products are shown in Exhibit VII-6. Constituents with <br /> Henry's law constants greater than 100 atmospheres are generally <br /> considered amenable to removal by air sparging. <br /> Exhibit VI" <br /> Henry's Law Constant Of Common Petroleum Constituents <br /> Constituent Henr ez La-sv Constant At 20'C (atm) <br /> Tetraethyl lead 4700 <br /> Phylbenzene 359 <br /> Xylenes 256 <br /> Renzege 230 <br /> Toluene 217 <br /> Naphthalene 72 <br /> Ethy€ene dibrcmide 34 <br /> Methyl t-butyl ether 27 <br /> Prcduct Composition And Boiling Point <br /> Because petroleum products are often classified by tlheir boding poet <br /> range and because tine boiling point of a compound is a measure of its <br /> volatility, vapor/dissolved phase partitioning of the dissolved petroleum <br /> product can be estimated from its boiling point range. However, because <br /> vapor/dissolved phase partitioning is a function of both volatility and <br /> solubility, boiling point range should be used only as a gauge to consider <br /> effectiveness for the product in general. <br /> The most commonly encountered petroleum products from UST <br /> releases are gasoline, kerosene, diesel fuel, heating oils, and lubncating <br /> oils. Petroleum products are a complex mixture often containing more <br /> than 100 separate compounds Each compound responds to air spargnng <br /> with differing levels of success based on its individual volatility. Shown <br /> in Exhibit VII-7 are the boiling point ranges for common petroleum <br /> products. <br /> October 1994 VII-9 <br />