"John thanks for the breakdown. I wonder if youhave any thoughts/explanation or description of equilibrium and its purpose in our hobby. I know that distillerys with towers that are 60 ft high and 5 feet across for example Have diferent take off points to separate factions for commercial purposes.

But is there any use for it in our level of operations.
I dont understand enough about it to ask a more specific.intelligent question:)"

My first thought is that I know very little about the "big iron."

"Equilibrium" is just the condition where the components of a mixture have been separated in the column ... and the state of the column is relatively stable. This is usually the result of running the column in full reflux for a long time. The more volatile components end up at the top and the less volatile components are at the bottom.

But I don't like to focus on the wrong things. What I mean is this: I think in this hobby it's very easy to get distracted and make assumptions that simply aren't valid. I do it all the time ... but I'm getting better about it. Or we can spend time fussing over things where we don't get much bang for the buck. For example, we'll split hairs over a half of a degree here or there when we run our columns, but we'll ignore the quality of the wash we're working with -- that sort of thing. I think the same things happen when we talk about reflux, fractions, equilibrium, separation.... So I do my best to stay focused on the fundamentals. When running the column I can only control three things (1) the power, (2) the cooling water flow, and (3) time. Everything else is irrelevant ... there's no switch or button or valve labeled "Equilibrate" or "Collect azeotropic quality distillate."

Of the three things I can control, the one that is the least understood IMO is that power knob. A good example is one of our past members who bragged incessantly about how fast he could run a 10 gallon wash through his supercharged nuclear powered column ... and then (after beating his chest) would wonder why he could never get his abv even close to 90%.

Ok ... so where am I going with this? Well, that power control knob is just as important as the valve that controls the flow of cooling water to the column condenser (IMO more important). If I drive my column too hard I may just be fooling myself: I can turn up the cooling water all the way so nothing is coming across. Then, since nothing is coming across, I assume that I must be in full reflux ... which in turn must mean I'm getting good separation. All the while I'm ignoring (or I'm completely unaware) that I'm driving the column way too hard. I don't even realize that I've increased the mass transfer within the column ... that I'm mixing the heads ... that I'm not getting good compression ... that I really haven't achieved equilibrium at all. And how would I know? I don't ! How could I? ... the only indicator I have is the thermometer and it's above the column condenser ... so it tells me absolutely nothing!

But if I drop that power down after I start getting some output, draw off the fores, then cut in the cooling water until the output stops and let it sit ... well, then I have a much better chance of actually achieving true equilibrium ... and getting some decent heads compression. Then, if I collect very slowly, maybe I'll be able to draw off those heads efficiently. When my nose tells me I'm into the hearts maybe I'll bump up the power a little (if necessary) ... then perhaps let it sit in full reflux for a while before collecting again. Then I can cut back on the cooling water and collect a bit faster. And all going well, I might get the results I want.

All of the above is just a verbose regurgitation of what Scotty has been saying for a long time:


--JB

But if I drop that power down after I start getting some output, draw off the fores, then cut in the cooling water until the output stops and let it sit ... well, then I have a much better chance of actually achieving true equilibrium ... and getting some decent heads compression. Then, if I collect very slowly, maybe I'll be able to draw off those heads efficiently. When my nose tells me I'm into the hearts maybe I'll bump up the power a little (if necessary) ... then perhaps let it sit in full reflux for a while before collecting again. Then I can cut back on the cooling water and collect a bit faster. And all going well, I might get the results I want.

All of the above is just a verbose regurgitation of what Scotty has been saying for a long time:


... just enough cooling water to do the job and the lowest heat setting that will produce the product.




Good description JB. Alot of people seem to think more heat gives them a good product faster, and that's true, except the GOOD part.
In reflux it is imperative to equalize the column, and that can not be done with a high heat. As you said it's a balancing act between cooling water and heat. The only way I can tell when my column has stabilized is when the temp at the top of the tower stabilizes. I then leave it alone for at least 45 minutes before I start easing back the cooling water and start to draw off product.

I've been experimenting with stabilizing the column at 69 degrees, or close, from the start in order to draw off all the fore shots and the majority of the heads. This seems to be working pretty good so far.

Merry Christmas Everyone!!!!!!