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# Calculating rate of water removal from a material when temperatures are known

I need help.

In a wood chemistry/wood physics lab, we were asked to place a piece of wood that contained approx. 64% moisture content in a hydraulic press where we applied a constant 400 psi pressure and applied a constant 400 degrees F of heat. We inserted a Type K thermocouple into the piece of wood so we could record internal wood temperature. The data set we derived from the experiment was a time temperature curve that is shown in the attached. The data indicates the total amount of water removed during this experiment.

But, what we are asked to do is mathematically determine the amount of water removed during each time interval presumably from 212 degrees and higher.

Could someone please help me understand how to calculate the incremental amounts of water that were removed in this experiment.

You don't have to do all of the calculations, but if you can show me a few and get me headed in the right direction, I can take it from there.

#### Solution Preview

This is primarily a calculus problem.
Remember the water in wood does not evaporate unless the latent heat of vaporization at 212F has been overcome. You can clearly see this on your temperature profile. There is a plateau section at 212, indicating the phase change of water.
The graph clearly shows us the loss of ...

#### Solution Summary

Guidance is given as to how to calculate the rate of water removal from a piece of wood when temperatures are known.

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