in need of help with wiped film first pass parameters

Calling all extractors, I am in need of assistance with my KDL thin film distillation machine.

I am starting with winterized, short pathed CO2 oil with roughly 70%-77% THC content, I get my vac down to 3.8 -4 , running it usually goes up to 5.8-4 - 1.9-3. i am stuck in the 82-86% THC world after my first pass, my second pass does a wonderful color strip but only bumps my THC levels up 1-2%. My fear is that I am burning off THC on my first pass, and because of that my second pass is not doing much besides taking off color, and converting or burning my THC further. Does anyone have any first pass parameters or temps they suggest to run my baths at?

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To get the best assistance from this forum,
Please clarify:What vacuum units are you referencing? (3.8-4 what? Pa, torr, mbar etc) what temps are you currently running your baths at? Wiper speed and feed rate?
are you using any pre-processing techniques of the material to be distilled?

A common operation utilizes 2 passes, 1st pass (light cut) is for removing your “lighter than cannabinoid” components (cannabinoids stay on residue side) Then 2nd pass (deep cut) should take place at a much lower vac depth (cannabinoids condense as distillate).

*There is already thread on WFE parameters somewhere here that you may find helpful enough to get where you wanna be.

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3.8 -4 torr, i use 160-170 C on my evaportator bath, 90-110 C on my feed tank bath, feed speed 100, wiper speed is 250, no pre processing techniques besides winterization, and short path to take off solvents and terpines.

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Your temps are in the right range for a deep cut. some like to run hot around 180C with internal condenser around 70-90C. (Theres many ways to skin this cat)
But we still need to get that vacuum depth much lower, definitely wanna be less than 200-300millitorr, and optimally less than 50millitorr(on second pass after volatiles have been removed allowing sub 50millitorr vac to be achieved). What kind of vacuum pump are you using? Do you have a diffusion pump too? Either way, an oil change in the rotary vane (if thats what you have) might be due, and/or theres leak(s) in your system (check dosing pump for sealing issues too).

Also, Just wanna make sure Im seeing this correctly: I take it you are using a short path wiped film evap right?(internal condenser) & not a “Thin film evaporator” (where condenser is located external to evap body, which can not achieve the low low vac you need to be evaporating cannabinoids at the temperatures your running at.

3.8 ^4?? If so u need deeper vac

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3.8 E -4 torr. Note the negative sign. That’s 0.38 militorr. Very very deep vac.

i am using an Avac Industries vaccum pump, no diffusion pump, but i have a turbo pump on it. i use a table size short path system before the thin film to take off solvents and strip terps. am i burning the oil? am i converting? i get to 190C on the shortpath under vaccum and 130C vapor temp. than i run the first pass i listed.

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