[Open Source Design Project] - Falling Film Evaporator



Basically one of my main jobs at bzb is to test heater and chiller combos. The 36kw combo netted us 174L/hr but we offer multiple options as far as speed goes so you can upgrade heaters and chillers in the future and keep using the same steel and everything.


Absolutely will! Can’t wait!!


Where do you think your current design caps out?


I’d guess 250L/hr before we expand it and add more surface area.


Thanks for this!


Price for steel only to Rotarua NZ?

It’s not quite legal there yet, but they are planning on cornering the global market :wink:


~1gal/hr per kw is ‘good’ efficiency.
you guys have covered a lot of the design difficulties so far.
they behave much differently with extract than clean solvent :slight_smile:


When I was doing butane extraction, I always wondered why not use a Heat Pump. I thought it was inefficient that I had a device trying to keep one thing really cold and another device to make hot water. Using a single heat pump I could achieve both processes. Couldn’t you do the same for the FFE? Some type of heat pump that is dumping super hot water where you need and at the same time super cold water on the other side of the unit. Similar to a peltier plate in CPU coolers. One side is really cold, the other side is really hot. Or maybe they all ready do this… :man_shrugging:


Just get a water cooled chiller and route the water used to cool the chiller to what ever you need hot. It may need some supplemental help but should be more efficient than having heating and cooling separate


Just figured out how they mate the tubes with the tube plate. Im thinking that everything on this design will be orderable online except the tube assemblies which I am considering having made locally here in California. Check out the basics of the tube expansion process that locks the tubes into the tube plates:


Also, I know that for the evaporator side shell and tube is the obvious choice for heat transfer since it is going to need to be serviced regularly due to the nature of our solution. HOWEVER, after some discussion with @wakawakalj I wondered if a plate type HE would actually be a better choice for heat transfer when condensing the (presumably) pure solvent. Plate type heat exchangers are typically more compact for a given surface area and as such tend to be the more cost effective solution at larger scales. Read below for more and let me know if you can think of why this wouldn’t be the best solution for the condenser.



Saw this when searching #fallingfilm tag on Instagram.


An expander is a handy tool to have, you can trace the tool’s origins back to boiler making. Having a tighter fit up allows you to make a “fusion” weld, rather than filling with welding rod.


I don’t think most industrial chillers are getting the cooling water hot enough to do what we’re after here (don’t know what everyone is running their FFE’s/Rotos at but I’d expect 70+*C), though I recognize that may depend on flowrate. Problem is, if you cut down flowrate of the cooling water to get a higher outlet temp, you’re going to cut down the ability of the chiller to chill the circulated coolant - it would be similar to running an air cooled chiller in a very hot room. In order to achieve a descent steady state you would have to drastically oversize the chiller to where it still has sufficient cooling capacity to condense with a lowered cooling water flowrate, and then I’d be concerned about what kind of impact that might have on longevity of the chiller.

I think 1244farms is onto something with the heat pump idea, though I don’t know enough about heat pump engineering to say whether thats a viable option or not. Most I’m aware of are for achieving temps human beings are comfortable in, which would probably be warmer than we’d want to condense at and colder than we’d want to evaporate at.


I know that for the evaporator side shell and tube is the obvious choice for heat transfer since it is going to need to be serviced regularly due to the nature of our solution

I’m not certain I agree with this part of your statement. Gasketed plate style heat exchangers are easily serviced (admittedly, somewhat less easily than shell and tube) and an order of magnitude less expensive than shell and tube ones.

I agree that plates definitely make more sense on the condensation side.


is this custom build or you use parts from from online ready to go ?


Howdy gang,
Just checking out Delta Seps new falling film system and it appears that they have beat me to the punch so to speak. See the photo below appearing to show plate heat exchangers used for condensation of ethanol:


Yup, it’s a pretty interesting setup. They also use a liquid ring vacuum pump to minimize the energy required for condensation, which is nice to see as I had thought about that kind of thing but didn’t know the right equipment to make it work.

Fairly overpriced in my opinion, but that’s true the of vast majority of equipment sold to this industry.


had to ask the all knowing one: WTF is a liquid ring pump?


Know the surface area on that thing?