[Aeroturbo]

I've been working on predicting the VOC content of waste gas from an industrial dryer which contains trimethylolpropane [TMP] (2-ethyl-2-(hydroxymethyl)-1,3-propanediol) which is a solid that melts at 58C and boils at 285C. The drier has wet air leaving it at about 72C, and I've calculated from vapour pressure data for the solid (0.0028kPa) what the VOC content of the exhaust gas will be.
However I've now discovered that the fan drawing air from the drier is an irrigated one - it has water being fed to it at quite a high flowrate. Hence the air containing this TMP will be scrubbed and form a solution as TMP is very soluble in water (>50% w/w at ambient temperature). The concentration of TMP in the water if it were all scrubbed out would be low - only 0.08% w/w, at about 72C.
What I don't know is what sort of effect this will have on the VOC content. Can anyone give me an estimate (even order-of-magnitude) of the vapour pressure of this material over a water solution?
Many thanks for any help,
AT

[eugenedakin]

Hello AT,

The scrubbing of waste gas sounds similiar to one of my areas of expertise (removal of sour gases from natural gas).  Since TMP is highly soluble in water, and water is injected below its boiling point, TMP will definately be lower in the gas phase.

The effect of measured VOC in the gas phase will be signifacent if the concentration of waste gas from the drier is low (0.1 %), and will be less signifacent if the concentration of TMP emmitted is high (50%).  The answer to the magnitude of waste gas will be dependant on the concentration of waste gas.

Another factor to be considered, is the measurement device.  Does the device only measure the concentration of the gas phase, or will the measurements be affected by TMP in the liquid phase which adheres to the sensor?

I hope this helps,

Sincerely,

Eugene