if it's benzene in a gaseous state, 1 million ppm.
If it's mixed with other stuff, it gets very specific and complicated and would require a bit more information, like ppm at what point, diluent specifics, etc.
Yes the benzene is in a gasous state as it is off gas from vacuum evaporator. There are other components and the mix can be complicated but, I am considering benzene as a worst case pure stream. Can you provide the details as to how you have calculated?
I would like to use the calculation for the other VOC that I may have.
You have not given enough information to help you. For example:
1. What units are you referring to by "ppm"? Parts per million, pounds per minute?
2. You have not told us how much Benzene there is in the off gas.
3. If ppm refers to parts per million, ppm is a ratio (typically based on mass or volume) of a component in a group of components (For example, 100 ppmV of Benzene in air can refer to refer to what percentage of Benzene in 1 SCF of air by volume). As such it is not compatible with flow measurement units directly. As CWW stated, if the stream is 100% Benzene, the answer is 1,000,000 ppm or 100% (e.g. PPM = ratio x 1,000,000).
4. Since it is likely that you are likely to wanting the parts per million Benzene in the off gas, you must have an analysis of the stream (typically done by a gas chromatograph) to get the ppm. The ppm is not related to the flow rate (40 kg/hr), however, the ppm and flow rate can be used to calculate how much Benzene (kg) you have flowing in the stream.
If this is going to the atmosphere, there is likely a continuous emission monitor (CEM) is present on the stream and it may have the measurement of ppm of Benzene in the air.
5. If you were referring to pounds per minute, there are calculators on the Internet that will provide that conversion.
William (Bill) L. Mostia, Jr. PE
ISA Fellow, SIS-TECH Fellow,
SIS-TECH Solutions, LP
Any information is provided on Caveat Emptor basis.
The calculation was easy PPM works like percentage only the base is a
million. So boiling benzene will put out 100% or 1,000,000 PPM. But in the real world you would have to know the proportion of each constituent to calculate the PPM of Benzene. Your problem is finding out those numbers which would require rather complex analysis. There may not even be a practical way to get some of the data.
> Can you provide the details as to how you have calculated?
You've been had, Phil. Reread Curt's post.
He's saying that if it's pure benzine, the concentration will be
One million.....parts.....per million [tempted to use a Dr. Evil accent here]
I think his point is that your request with no more information is kind of like asking for a conversion factor between pounds and nanometers. I was going to post and try to make that point, but Curt did it far more creatively that anything I would have thought of.
