Ever wonder what happens when you get a “Residual Solvent Test” back and see there is isopropyl? This is triggered by 4 different isomers at times.
Generally an alcohol one will be present if you use alcohol to clean your gear and do not allow it to evaporate.
The use of alcohol, especially with cheap ethanols, is a mixture of denatured components.
We suggest you use 99.9% denatured clean-room alcohol.
We suggest “Nitrogen” because even after the end of the day you can flush your clean vessel with nitrogen, which is sent down the path to desiccant drier, pump, coil and out the recovery hose. Essentially, you can dry the whole path.
The desiccant drier captures molecules that are heavier and whole in the hydrocarbon passes.
So if you are distilling and the majority of the gas is “Butane” or “Propane”, then things such as terpenes, alcohols, esters, pentanes, etc will be caught while the majority of butane or propane passes.
In the simplest way possible, you don’t need anything but cutting recovery short of 0psi.
Typically you are running around 100-110deg f, Shut system off, lock off desiccant drier, and bleed pressure out of your vac port. You may now open and clean out your system. If you smell any unpleasant odors -that means you did the job right and left it behind.
If you recover too far down you may have carried over your residual components found in foreign solvents.
However, when we talk about fuels similar to a Praxair 99.95%+ or Eco-green 99.97%+ source gas, a desiccant drier can easily take it to 99.99% in one pass.
if you think we need to add anything to this please let us know. we want people to be doing these tasks correctly firstname.lastname@example.org -JBV