BOREAL LASER GasFinder2, Руководство по эксплуатации

Страница: 57 / 74

9.7
Boreal Laser Inc. GasFinder2 Operation Manual — Appendices July 17th 2017
Appendix E — Conversion from ppm to mg/nm 3
(Parts per million to milligrams per normalised cubic metre)
In this example Hydrogen Fluoride (HF) is used to illustrate the conversion.
The molecular weight (mw) of F = 18.998 g/mol
The molecular weight (mw) of H = 1.008 g/mol
The molecular weight (mw) of HF = 20.006 g/mol
The Universal Gas Constant (R) = 0.08206 litre / mol.K
One mole of any gas at STP* = 22.41 litre / mole
Therefore, at STP*, 1m
3
of gas = 1000 moles/m
3
22.41
= 44.6229 moles/m 3
1ppm of any gas = 1 x 10
-6
= 44.6229 x 10 -6 mol/m 3
1ppm HF = 20.006 x 44.6229 g x mol
1,000,000 mol x m
3
1ppm HF = 0.8927 mg/m
3
at STP
*STP refers to:
Standard Atmospheric Pressure (P) = 101.325kPa
Standard temperature (K) = 273.15K
Adjustments for different temperatures and pressures:
Actual concentration = 101.325 x new temperature(K) x STP concentration
new pressure(kPa) 273.15
eg. At a pressure of 94.34 kPa and 20°C:
Actual Concentration = 101.325 x 293.15 x 0.8927 mg/m
3
94.34 273.15
= 1.1527 x 0.8927 mg/m
3
1ppm of HF = 1.029 mg/m
3
at 94.34kPa and 20°C.