Power control

[theozzman]

I have a question regarding power management for my still.

Just to confirm, it is a "Pure Distilling Still" copper reflux colum with electric boiler which has the 2000W element.

In my other topic we discussed means of controlling power to the element. I am in the process of getting a suitable voltage controller and power monitor so I can be sure what is going to my element.

My question relates to how this may work....does the element run at full all the time? Or is it on some type of regulator? I wondered this as it seems to get the temp to a certain point and sit there.

If the element does self regulate somehow, then how can I actually know what it is doing? Say for example I cut power to the element down to 50%, is it still try to do its own thing, or is it actually at circa 50% power?

I hope this makes sense....perhaps some of the owners of these type of stills could chime in? My column has been extended by an extra metre, but it still regulates head temp to the required 78.3 or very close by.

For that matter, can someone explain to me how this type of still hits the 78.3 mark without operator control, especially now that I have extended the column and the head still hits the right temp even though there is an extra 1m of copper pipe and packing there?

Many thanks,
theozzman

[Meatheadinc]

the temp is in direct relation to the composition of vapour/liquid.
the boiler will boiler at a temp determined by alcohol %

Pure water boils at 100 deg
pure ethanol boils at approx. 78 deg

The mix of the two boil somewhere in between and will increase in temp as alcohol is depleted.

the head temp will indicate vapour temp. vapour temp is also governed by composition

the boiler is not changing power settings. temp increases as alcohol depletes. full power full time

you don't really need a controller

[wiifm]

... you don't really need a controller

says the man with the most complicated controller on the forum :teasing-tease: :laughing-rolling:

[wiifm]

In all seriousness, a power controller will only regulate how much energy the element puts into your boiler.

This will affect your heat up time if you turn down the power early and will affect the amount of vapour produced by the boiler once it is actually boiling.

Some people will have a powerful element or two to reduce heat up time, then use a controller to reduce the power output of the elements to match the cooling capacity of their condenser and the vapour / liquid capacity of their column.

As MH said, the chemistry determines the temp in the liquid and vapour states.

[theozzman]

Ahh that makes alot more sense to me now. Simple really I guess.

So even when I hook up a pot still to this boiler I do not absolutely need a controller? I figured with the pot I would be best suited to run it full power until the output starts and then back it off it required to run it slow on spirit runs.

Thanks!

[woodduck]

I don't know about that. :-B :think:

For a reflux still it may not be as nessesary as it can reflux back to the boiler but with a pot still unless your take off is already pretty slow (fast drip) you will need a power controller to slow down your spirit runs to avoid excessive smearing, i would of thought anyway.

There are quite a few threads on the volt controllers in the electrical section that should be able to help you out.

Good luck

[Meatheadinc]

Although you do not require a controller for you reflux still, you will require a controller for running in pot mode

[Brendan]

The guys have answered it already, but I'll put it in my words as well.

Your misconception on the temperature is a common one, so have a look in the Newbie's Corner for a thread on Controlling Stills with Temperature. Essentially, you can't...just think of boiling water; with more power can you take it to 130 degrees? No, because it's boiling point is 100 deg C. Now in your boiler there is ethanol as well as many other components, each with different boiling points. The boiling point of that total mixture will depend on the quantities of each, which will also constantly change as certain compounds boil off. This is why your vapour will start in the 70 deg range, and slowly rise towards 100 deg over a run, as it gets closer to being pure water...cool eh?

Controller wise, the power is not delivered in bursts in these applications. That is how some heaters work, like stove tops, but that method is no good here as you can't hold a constant vapour speed (the steam rising up the column). The controllers we use, limit the amount of power delivered to the element which controls how hard the boil is pushed in the boiler. Remember you can't control the boiling point or the temperature as such, but you can control how fast it gets there, and how much vapour you are pushing through the column.

Hope that helps in some way mate :handgestures-thumbupleft:

[theozzman]

Thanks Brendan and everyone.

Very helpful. I am getting my head around it...so in my case the power applied is constant, as products boil off, the temperature in the still head increases as various products with higher boil temps boil off, whilst element power remains constant.

I will go have a thorough read of basics....I have done alot of reading but I guess nothing prompted me to investigate this until now. My main reason for wanting temp control was so I could run the pot still via watching output, for a slow and gentle spirit run. I have my eye on a a suitable controller.

It is very cool Brendan, for sure! Thanks again

[CH3CH2OH]

Great way to put it Brendan.

An element controller really only helps you fine tune your rig's sweet spot.

Some commercial stills such as a Mueller have a thermometer at each plate where you can see the temperature of the vapour stacked at each level of the column. When you are dealing with a 12" column, there is a lot of vapour and condensate in the column when it is equalized.

For a plated column, too fast of a take off speed, changes of heat input into your boiler (playing with your electric controller or gas valve once equalization and stacking of fractions has occurred) or fluctuations of water volume/temp to your RC can disrupt this stacking and smear fractions. RESIST THE TEMPTATION to play with your settings, especially your element controller, once you have reached equilibrium, let chemistry do the work for you. When you finally get a feel of how you still functions, the setting on your element controller, RC input, take off rate, leave it alone and watch that chemistry in action. You can not speed this up, be patient once you learn your rig's sweet spot. If you change one variable, you have an effect on the all of the others and it is usually negative!! You can only take off product at a rate that allows everything else to remain in balance. If something changes in that balance, throw your RC back into full reflux and let it re-equalize your column. Empty your parrot and chuck that stuff into your feints jar before you continue the takeoff.

Running outside with a breeze, poor cooling water set ups, inconsistent water pressures, take off speeds all can negatively change what is happening with the equilibrium in your column, especially in a small diameter column. Changes in any of those factors affect a 4" column much differently and much quicker than in a 12" column.

A quote from the wise little green guy can be applied to most things in our hobby if you want great results "PATIENCE YOU MUST HAVE MY YOUNG PADAWAN".

And another Yoda quote for those of you with HBS purchased equipment and their advice "YOU MUST UNLEARN WHAT YOU HAVE LEARNED"!!!

[CH3CH2OH]

sorry, just re-read things and my post is geared to plated not pot!! Either way, it is all about balancing what is boiling and what is getting taken off!!

[theozzman]

Thankyou mate.

Yes I am beginning to understand. I am not in any way trying to speed things up, just do it better. I have read guides to running reflux columns and they often refer to small adjustments in gas or power.

As for a pot still, from what I know, I wouldn't imagine running with no control over the gas or electricity would be very helpful. This is what I ahve been thinking about lately, I want to run in pot mode and really want to have the output come out nice and slow, not hard and fast flat out etc. I want control over what speed my output runs out of my pot (when built).

As I am running with the T500 2000W boiler, I figured that there was little sense in starting from scratch right now when I have a useable boiler and 2000W element ready to go. I just need the pot still head, thump and worm or whichever method I use. The boiler just provides heat, whatever means it uses.

I am learning to run my reflux via careful control of the output valve....ie; take off fores slowly rather than all the way open to keep the fractions compressed and still run at about 95% reflux.

If I am wrong about running my pot please let me know. I do not intend having any thermometer on it, at all, and will be running it with a slow output on spirit runs, thin stream or drips etc.

Cheers guys!