Once the column is up and running and you are pulling 95 percent would you agree the top of the column doesn't change temperature?Ben wrote: ↑Mon Sep 26, 2022 7:44 amYou don't, that's the point. The post I deleted rambled a little about homogeneity, porosity and vapor channeling. Short of it is I think that's one of the things that makes random packing (SPP or Dixon rings) work better than something homogeneous like marbles.drmiller100 wrote: ↑Sun Sep 25, 2022 11:31 am
Channeling I have Called stove piping. I find it fascinating you theorize marbles would be worse for this than spa.
How do you pack your spp so it is absolutely homogenous?
I disagree, the thermal mass of the vapor is much lower than that of the packing. A modest change in the packing design, or the conductivity of the material is going to effect the behavior of the vapor. If you are running fully flooded it matters less, and whether that is a metric that you can detect or not I don't know, but it certainly effects the behavior of the vapor in the column. Remember we are often at a threshold with the constituents of the vapor where they are very close to condensation temp, so removing or adding a small amount of heat impacts a portion of the vapors phase, if the vapor is losing heat to the packing it will condense, adding to the plate effect. More condensation throughout the column should lead to better separation (higher HETP, which we see). The vapor management condenser is not the only place condensation is happening, it is more like a control and a location to pull heat so you can stack the column temp, and send more reflux back down to mingle and reboil. It probably matters less if you are using something like marbles that are much less conductive than a metallic packing material, but I still bet you see a thermal gradient top to bottom, or a pressure drop without the condenser active.drmiller100 wrote: ↑Sun Sep 25, 2022 11:23 am [
Thermal mass is meaningless. The column comes to temp at sbout the same time hooch starts dripping out the top.
There is a pretty good debate about it here: viewtopic.php?t=30727
Likewise each spot IN the column does not change temperature.
For sure the boiler is hotter than the condenser but each spot along the way is a constant non changing temperature.
This is easily tested and pretty basic.