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Module 2: Characteristics of Gases - Oxygen Basis Conversions
Conversion of Concentration Data to Standard Oxygen Basis-
Calculator:
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Correction of Concentration (Measured
Standard O2 Basis)
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Summary of Concentration Units of Measure
Objective
- Convert concentrations of gaseous pollutants between measured and standard oxygen levels.
Conversion of Concentration Data to Standard Oxygen Basis
Pollutant concentrations specified in U.S. air pollution regulations are often expressed on a 7% oxygen basis. In some other countries an 11% oxygen basis is sometimes used. These formats are used to account for dilution air that often enters through fans, cracks in ductwork expansion joints, and air pollution control equipment. The 7% and 11% oxygen formats for the concentration limit ensure that regulations are fair for all sources, regardless of the extent of ambient air dilution of the effluent gas stream prior to the continuous emission monitor or the emission test location. It is also useful for comparing emissions from different facilities having substantially different oxygen concentrations in the gas stream. The standard equation for the correction of concentration to a specific oxygen level is as follows:
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Where:
The value, 20.9% in Equation 1, is the oxygen concentration in the atmosphere.
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#1
- A power plant has a mass emission rate of 100 lbm/min of SO2 at a 10% oxygen level. What is its mass emission rate corrected to a 7% standard oxygen level?
TIP: Only concentration data and gas flow rate data are corrected for moisture and oxygen content. Mass emission rate data is NOT corrected for these two constituents.
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#2
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When a pollutant concentration is corrected to a standard oxygen level, does its concentration increase or decrease? See equation below and Table 1.
Correction of Concentration
(Measured 
Standard O2 Basis)
Purpose: This calculator converts concentrations of gaseous pollutants between measured and standard oxygen levels. It allows you to input a value for the standard oxygen level. U.S. air pollution regulations often state pollution standards on a 7% oxygen basis.
Restrictions on Use: All concentrations must be entered on a dry basis. Do not use commas when inputting values. Output is invalid when inputted values for concentration exceed 100% or 106 ppm.
Notes:
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This Java applet may take a few minutes to load.
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Sometimes calculator output is provided in an exponential format in base ten as shown below.
5.2e003 = 5.2
103
5.2e-003 = 5.2 10-3
- Inputting non-numeric characters such as commas and percent signs will result in erroneous output. (Decimal points are fine to use.)
Summary of Concentration Units of Measure
The following tables present a summary of the concentration units of measure discussed in Module 2. These tables are an extension of the tables presented earlier.
Practice Problems
Oxygen Basis Conversions
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Instructions:
- Complete the Practice Problems before proceeding to the next lesson. Click on the button below.