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I am working in China at the moment and we did some SO2 sampling at the stack of a biomass incineration power plant.
We used a portable analyzer with a built-in cooler for moisture removal and the SO2 concentration is given in ppmv.
We needed to convert the ppmv values to a standard unit of mg/Rm3; where the reference conditions are 0 degC, 101.3 kPa, 6% O2 dry gas. The equation I used to do this is was:
SO2 [mg/Rm3] = SO2 [ppmv] * (molar mass [64]/molar volume [22.4]) * ((21-O2%ref)/(21-O2%act))
The molar volume of 22.4 being used was for gas at 0 degC, 101.3 kPa.
I am being told by our Chinese client that this is not correct and that I need to add additional corrections for temperature and pressure. The equation they suggest is:
SO2 [mg/Rm3] = SO2 [ppmv] * (molar mass [64]/molar volume [22.4]) * ((21-O2%ref)/(21-O2%act)) * (273/(273+127)) * (99970/101325)
With temperature and pressure values for the flue gas inside the stack. This formula gives lower SO2 concentrations than my original calculation, but I was not aware that the temperature and pressure correction were required when converting ppmv.
I am being told that the equation suggested by the Chinese client is the standard used by the government for emission reporting, but I am always hesitant to trust this type of statement immediately because misunderstandings and miscommunications are common.
I am not a chemical engineer and don’t know the science well enough to effectively demonstrate which equation is correct. Can someone please provide some guidance?
We used a portable analyzer with a built-in cooler for moisture removal and the SO2 concentration is given in ppmv.
We needed to convert the ppmv values to a standard unit of mg/Rm3; where the reference conditions are 0 degC, 101.3 kPa, 6% O2 dry gas. The equation I used to do this is was:
SO2 [mg/Rm3] = SO2 [ppmv] * (molar mass [64]/molar volume [22.4]) * ((21-O2%ref)/(21-O2%act))
The molar volume of 22.4 being used was for gas at 0 degC, 101.3 kPa.
I am being told by our Chinese client that this is not correct and that I need to add additional corrections for temperature and pressure. The equation they suggest is:
SO2 [mg/Rm3] = SO2 [ppmv] * (molar mass [64]/molar volume [22.4]) * ((21-O2%ref)/(21-O2%act)) * (273/(273+127)) * (99970/101325)
With temperature and pressure values for the flue gas inside the stack. This formula gives lower SO2 concentrations than my original calculation, but I was not aware that the temperature and pressure correction were required when converting ppmv.
I am being told that the equation suggested by the Chinese client is the standard used by the government for emission reporting, but I am always hesitant to trust this type of statement immediately because misunderstandings and miscommunications are common.
I am not a chemical engineer and don’t know the science well enough to effectively demonstrate which equation is correct. Can someone please provide some guidance?
