Regarding the issue of the outlet concentration in exhaust gas condensation treatment
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For example: a mixture of 500 cubic meters of propylene oxide and nitrogen. Propylene oxide concentration: 3 g/NM3. The inlet concentration is taken at 20°C. Condense to -40 degrees. Could someone please explain what the concentration of propylene oxide at the outlet is? According to the Antoine equation, the saturated vapor pressure of propylene oxide at 20 degrees was calculated to be 57 KPA. -At 40 degrees, 2KPA. -At 40 degrees, using the formulas Pv=nRT and PM/RT=m/v gives a value of 60 g/m3, which seems incorrect. Please explain why this is not the right answer.
How can one use PV=nrt? It’s better to simply use Henry’s law. Knowing the saturated vapor pressure at -40°C, and also knowing the total pressure, the concentration can be calculated using partial pressures.
Hello, boss. I want to know where I went wrong; what does it mean if it’s calculated this way?
This post was last edited by Little Chemical Engineer on 2018-11-1 at 09:05. What does P represent in PV=nRT, and what does V represent? Please look it up. Also, how is the PV=NRT equation applied to mixtures?
If it isn’t mixed with nitrogen, the gas concentration can be calculated in that way, but for this mixed gas of yours, what’s the point of using such a calculation?
0.12mg/nm3?
It’s unlikely to be that low. I can’t find the Henry’s law constant. Can’t calculate it
Could the expert provide the calculation process?
The outlet gas is saturated with propylene oxide, with a partial pressure of 2 KPa, and the remainder is nitrogen. At normal pressure at the outlet, the molar fraction in the gas phase is 2/101.3. Assuming 1 mole of gas is emitted, the actual volume is calculated using temperature, pressure, and 22.4 L; the mass of propylene oxide is then determined from the mole fraction, and the mass concentration is obtained by dividing mass by volume.