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Because of the elevated concentrations of CO2 found in the <br /> influent ( . 75-1's) , this CO2 represents a significant amount of <br /> hydrocarbon removed. On average in a hydrocarbon molecule there <br /> are 2 Hydrogens (H) for every Carbon (C) therefore each CO2 <br /> represents the oxidation of one CH2 radical This indicates that <br /> for ever mole of CO2 recovered one mole of CH2 has been <br /> destroyed. The molecular weight of CH2 is 14 gm/mole . <br /> 14gm/435 6gm/lb= 0 . 032 lb/mole <br /> The volume of one mole of gas at STP = 22 4 1 <br /> 1 1 = . 0353 cf 22 .41 x 0353 cf/l = 0 79cf/mol <br /> Therefore one cf of pure CO2 represents <br /> 0 032 lb/mole / 0 . 79 cf/mole = 041 lb/cf of CH2 <br /> In gasses 1% = 1/100 of a mole <br /> 041lb/cf/1000<= 00041 lb/cf/°s <br /> A sample of the total flow from the vapor extraction system on <br /> 05/14/93 was analyzed for CO2 The sample contained 0 . 750 CO2 , <br /> normal air contains 0 033. CO2, the 0 . 7170-. in the sample is most <br /> probably the result of oxidation of the hydrocarbons either <br /> chemical or biological At the current rate of vapor extraction, <br /> 88 95 cfm it can be calculated that we are currently removing <br /> 37 7 pounds of hydrocarbon from the site per day as the result of <br /> biological or chemical degradation <br /> 88 95cfm x 0 . 717°1 x 0 00041lb/cfm/0-. x 1440min/day = 37 7 lb/day <br /> FLOW RATES <br /> Flow rates are measured at the site by use of orifice plates . A <br /> one inch orifice is placed in line for each well and two one inch <br /> orifices in parallel are used to measure the total flow <br /> An orifice plate restricts the flow of air across it This <br /> restriction causes a pressure drop across the orifice . By <br /> measuring the resulting pressure change across the orifice it is <br /> possible to calculate the air flow rate . <br /> The flow rate is calculated by the pressure drop (millimeters <br /> (mm) water) across a square edge orifice plate <br /> Ve = CK sgr(P) Q = AVe <br /> Where <br /> Ve= velocity in feet per minute (fpm) <br /> C = Orifice Coefficient = 0 65 (for orifice used) <br /> K = Constant = 794 . 6 mm water <br /> P = Pressure differential across the orifice <br /> Q = Flow rate in cubic feet per minute (CFM) <br /> A = Area orifice in square feet . 1" = 0 00545 ft2 <br /> Q = A X 0 65 X 794 6 X sqr (P) <br /> page 4 of R604 , 07/09/93 <br />