Continuous stripping still

[violentblue]

Whats the function of the three-way valve? I dont think you should mix spent wash with the steam generation system, to avoid reboiling yeast cells. if you do, you could use spent wash only for steam generation, you willsave on energy doing that.

point of using a 3 way valve is to choose between sending the spent wash to the boiler or to drain it directly. if you were sending it to the drain, then you'd open up the line fron the coolant water to keep the boiler full.

Create an overflow exit "waterlock" for the spent wash too, and maybe connect the exits further down to cool the spent wash making it smell less, and being nicer to your plumbing.

I had actually drawn that up, but felt it made the drawing a little difficult to follow. but it is a good idea.

Also be sure to insert the wash into the center of the column, if you follow your drawing it is inserted at the column wall, which might make it follow the wall, reducing column efficiency.

Hadn't thought of that, thanks.
the flow control is a great idea, but I'm shooting for an all gravity feed system, Like I mentioned earlier, I may use a thermostatically controlled valve to regulate the wash input. I'll probably play with the idea on the prototype anyway.

[violentblue]

Did some revisions of my original design, simplified the heat exchanges for ease of costruction and added a wash preheat, that uses the spent wash o heat the fresh wash.

and here's the (semi)complete unit.

there are unions so I can break apart the boiler and colunm, as well as ajoined copperwork, should I ever need to make any modifications to either.
stripped wash dropps into the beer keg, which acts as a collection vessel, and will also be the boiler for my Spirit still.

Needs cleaning and testing yet, which I will be doing tomorow.

[Nykter]

Beautiful.

It looks to be a little on the short side, is the column part half a meter or something like that? With a column that short it might be a little sensitive to the feed speed. How are you going to control the feed?

And the heat exchangers are in the wrong order, the spent wash should be 100 C and the product more 85-90 C, so if youre unlucky the top heat exchanger will cool the wash and heat the vapour before the second condensor. Dont know if it actually matters, and it would be much more difficult to build it the "correct" way.

Im really looking forward to hear about the test run.

[violentblue]

while it would be nice to swap the order on the heat exchangers for wash preheat, doing so would make the already complicated plumbing even more so.
In my previous working attempt (worked well, needed some tweaks) I had no wash preheat, and it seemed to work fine. So I figure, any preheating of the wash is helpfull, even if it isn't as efficient as it could be.

I have no doubts that there will need to be some improvements on this design, however this is a startingpoint

[absinthoman]

Did you test your setup violentblue? I'm planning on building a setup similar to this one.

[snuffy]

this is an interesting design. if your feed is too fast, the boiler temp will drop, so just watch the temp as you adjust your feed. Too fast and you'll spill ETOH through the stillage. Since you are going to be catching it in the keg, no problem. Too fast, just run it again slower.

You should be able to control the flow with a needle valve and changing the height of the feed reservoir. The needle valve will give you coarse adjustment and the height of the reservoir will give you the fine control.

If you want to automate, a pump controlled by a temp sensor in the boiler would do it. Use the pump to replenish the feed reservoir (which could be just a liter or two) and put an overflow back to the main supply.

Surplus Center has 10 of these little beauties left:
http://www.surpluscenter.com/item.asp?U ... A&catname=" onclick="window.open(this.href);return false;" rel="nofollow

[manu de hanoi]

Hi dudes, I uploaded a lengthy video about some of my equipment, continuous stuff towards the end. This may give you some ideas:
http://www.mediafire.com/download.php?ngjqcimmjzi" onclick="window.open(this.href);return false;" rel="nofollow

[violentblue]

added 12" to the column length as well as more packing,
I did a test run before the column extension using a 240v 3000w heating element, running on 120v making about 750w
it ran fine but the yield was less than I'd like, so I've up/down graded to a 1500w 120v element. should get things moving nicely.

so I'm set to go and do a stripping run on some molasses wash once the yeast is finished.

[aleksandr1]

good plan, and what about this thing in action? As i know not many of those continuous stills are really working.
but I saw the vid of such a still on ferromit.com, and it seems to be the real one.

[lloyd778]

Using your designs I have cobbled together a continous still. Yesterday was its first run so I'm still learning it. As you can see it is very simple and the mash pre-heater is very nice because it sucks so much heat from the distillate vapors that the liebig stays very cool. So far, i am quite pleased with it.

cont still 2 003.JPG (26.15 KiB) Viewed 6775 times

[lloyd778]

Yesterday, I processed 25 gallons of 12% wash through my little continous still in about 13 hours. With a potential of about 3 gallons of alcohol I collected a total of just over 5 gallons at 35% (about 1.75 potential "pure" gallons). Not good, but i was playing with different wash feed rates and temperature inputs and column packing. I could get different %ABV easily by adjusting these parameters to draw off between 20 and 55%. After a while, I settled in on drawing off at about 35%. I know I lost alot of alcohol in the spent mash out - overflow, but i really didn't care. This was just part of the learning curve and I was overjoyed with not having to deal with changing the 15.5 gallon SS beer barrel boiler kegs. It is amazing how much of the flavor came over in the low wines. I spent the day today doing the spirit run with my regular pot still. I collected 2 gallons of spirits at a combined 72% and 1/2 gallon of head and tails. I stopped collecting the spirits at 65% and stripped the rest into the faints jar until i got tired of it. So 3 potiential gallons became about 1.5 good collected "pure" gallons or about 3 gallons at 50% sippin spirit. Again, not very good results from 25 gallons at 12% but it was different than any other still that I ever used. As I re-read this thread, some things jumped out at me that passed me by on the first read through. And sure, I could re-distill the backset to extract more from it, but I'm not going to. I will just try to improve the results on the next run in about 4 or 5 days. And after the cost of putting together the corn and sugar wash and building the still minus the costs of store bought booze, I am at about breakeven now. Not too bad for a couple of days of tinkering. Room for improvement? Sure. I plan on it. This is just my first time through. If you have any ideas, I'd love to hear them.

[lloyd778]

A quick sketch of my my little still:

[rad14701]

Neat concept, lloyd778... Do you regulate the still by metering the input rate to keep the temperature at the top of the column within a specific range or do you use another method...???

[Master-Peter]

Real nice one!

I think you'd get a much better efficency with a taller column (better separation) and you dont need the temp probes, for you could control with a parrot. But that's only my theoretical point of view.
Another thing is, because of the probably small gap in the preheating system, any solids might stick there so there might be a risk of running the system dry.

Cheers
Peter

[lloyd778]

Hi Master-Peter and rad14701, you bring up really good points.

I'm not sure if a taller column is needed but next time i may add an extension to the bottom to increase its length and copper mesh packing just to see the effect. I'm really not after seperation like in other stills... just strip off all the alcohols that I can as quickly as possible for the least amount of money and effort. The temp probes were only for me to understand the still in operation. I did use a parrot to monitor the output and see the effect that different heats, packing materials and mash input flows were having on the strenght of the distillate. At first I was very concerned that I could run it dry but then quickly realized that the temp probes would alert me to that. And the first thing I did was to distill water with it to clean it and test it for leaks. It takes a while to boil off about 2 gallons of water so I have that time as another safty factor. As long as I am inputting mash into the system, I am always getting something out so the boiler always has its proper level. If nothing is comming out of the stillage hose then something would be wrong. In the event of a blockage in the still's feed system the overflow on the input funnel would begin to fill up its collection pail. That pail would be a good place for a water sensor that would sound an alarm. In fact, a sensor above the parrot would also make sense... if the alcohol level falls then it is only boiling off water so the hydrometer would rise and trip an alarm. So far nothing has come out of the overflow tube but I thought it was good to add it. With a still like this one you are certainly tempted to leave if for longer and longer periods of time.

Unlike must of the mashes that I distill, I filtered this one and think it is necessary if any grains were used in the wash.

What I've learned so far is to charge it with water first, get it really steaming, then start adding mash into the system. It flashes off the alcohols as some water and some of the tails sink into the boiler. The head temperature begins to fall as I increase the mash flow rate so for now I just try to keep the head as close to 100 C as I can. This is a small input stream and with enough heat I can get about 35% ABV low wines comming over in a small unbroken stream. Too much heat and too little input mash will lower the ABV. Too little heat and too much mash input will flood the column or cause the ABV to increase sharply... certainly dumping alcohol down the column and into the pot where it can easily be carried away with the stillage.This still works best when run hot. Another part of the learning curve for me because I have to unlearn some habbits that were formed by running my other stills. I added all 5 marbles to the boiler and it is a good indicator of the boiling action. If the marbles are silent and then furious with a big spurt from the stillage tube, I guess I flooded the column and must either increase the heat or decrease the mash input. I had 8 marbles but over time I've lost some of my marbles.

Next time I think I'd like to tin plate all of the copper parts before final assembly for easy cleaning and because it would just look so darned good.

[Master-Peter]

My idea would be, to put the takeoff port on top (where the temperature gauge is) and the feed as high as possible (where the current takeoff is). This would give the wash a bit longer way to travel down the packing. On the other hand the preheater could be extended for more heat recovery. The outer shell of the preheater could be bigger, so the gap in the liebing becomes bigger to avoid stuck solids.

I understand that you want to strip as fast as possible (me to) but on the other hand I'd like to get all alcohol out ... (sugar costs, yeast costs, nutriensts cost, and if time is money, fermenting time is a cost too, somehow). If we can make it "shut off on error" it could run unattended. Then I prefer complete alcohol recovery over short stripping times. The result counts - like on real striptease

Cheers
Peter

[rad14701]

Master-Peter, having the wash enter the column too high up can have adverse effects on the columns equilibrium, even with preheating... Most continuous columns have the feed point about midway down the column... Remember, the bottom of the column is hotter than the top... With that in mind, having the feed point too high up could cause vapor collapse which could then lead to column flooding...

[HookLine]

If we can make it "shut off on error" it could run unattended.

Not a good idea to leave a running still unattended, no matter how much 'fail-safe' techno-wizardy you got on it.

[lloyd778]

Hi Peter,
The difference between the 1/2" tube and 1" tube is more than enough room for anything I'll pass through it since it is filtered very well before going into the holding tank. My goal is to run everything in about 6 or 7 hours, once a week. This still can strip out a ferment while I pot still the low wines from last week. While everything is working along, I could be setting up the ferment for the next week and cleaning all the stuff up. This still starts producing very quickly, in less than 15 minutes it is ready for the mash to be fed into it. I could adjust my ferment volume to accomodate this time frame goal after I run a few more batches through and gain more experience with it before I do any plumbing changes to it.
As for costs, sugar is my only real expense. Most everything else is either very cheap or almost free. Once I get more experience with this still, things will improve as far as production and yield. I expect most folks leave lots of useable alcohol in their boilers at the end of a run because it is not worth their time or fuel to extract it. When I pot or reflux still, I usually call it quits when the ABV comming over falls to about 20 - 25% or so. I hate being so lazy but I'm too old to change now.
The length of the preheater was by guess and by golly. While it was running, I noticed the preheater shell got very hot and I became fixated on just what you are talking about. At the very least I should insulate it. To recover some of the heat from the stillage would be a nice trick because in my little still all of that is wasted.


Hi Hookline,
I agree totally that no still should be left unattended. One more reason that I'd like to get my "system" down to 6 or 7 hours once a week. I'd have enough to do with 2 stills running, setting up the next mash and cleaning everything.

Lloyd

[guerrila distilla]

i was looking through my pics today when i came across these ideas i'd drawn up over a year ago:-

the first still would use a 2" column, with a 3" sleeve to preheat the mash. the valve is after the reservoir to allow it to fill and be preheated. i decided to use a 5l boiler to lessen the chance of running dry.

the second still is easier to construct. i got the idea from the "ponu" still posted here somewhere. it uses a coil in the column to preheat the wash before it hits the packing. one idea i had to improve this is to send the feed tube further down the column into the middle of the packing to prevent the vapour collapse rad mentioned.

both ideas are real simple and wouldn't need the complex fabrication some of the stills posted here have.

what do you guys think?

[lloyd778]

Hi guerrila distilla, so nice to meet you. I've looked at your nice drawings for about an hour or so, off and on, but cannot quite get my head around them. Help me, OK? In drawing number 1, the mash input is regulated how? After you preheat and open the valve doesn’t everything in the preheater just dump into the column? If you choke it with the valve, how can you see/know the feed rate? I gotta be missing something. Just don't get it yet. Give me some time cause I'm slow, OK?
In number 2, I really don't get it. You refluxed everything down into the column before the vapor take-off. I can see that the coil is the pre-heater, but it also works as column reflux. How can the rising vapors get out? They are refluxed back into the column. Maybe at equilibrium the vapors will rise above the coil? Maybe. But if so the takeoff (product) rate will be tiny because the inflow rate needs to be input fast enough to achieve production levels thus providing cooling reflux. Just my opinion, and I know nothing. Believe me and all of my friends. I think number 2 is do-able if you lower the liebig intake at a point below the condenser coil. I really like the idea. Fast, simple, easy to fabricate and insulate. Easy to clean. Lots to like.

Mine works ok, but I would change a few things now that I've built it and run it a few times (good idea to build one and run it before you post, huh?). First, I'd make my pot more squat. Short and wide (like me). Next, I'd make the column thick (again like me). About 3 inches or so diameter. Height is only to help the liebig to clear the physical restraints of the pot and provide enough packing area for the steam to flash off the incoming mash into vapors - the packing is not for reflux. In fact, I'm trying not to have any reflux at all. This is a stripping still. And certainly, I'd give plenty of liebig cooling because the takeoff (product) volume is more than normal output on a different kind of still. As a test I built a small one. It worked so well I use it all the time now. But to do it again, I would definitely do these minor improvements. Squat and thick, that's the trick.
Keep cracking, g d. It is ALL about vapor flow. And yes, bigger IS better. But taller is not the real advantage here. The 1/2 inch vapor takeoff on my rig should be about double that, at least. Thinking then I could really let her rip! Till next time g d…. you got me thinking and scheming.

778

[Nykter]

Hmm both ideas are equal in function I think.

Arranging preheating this way will induce reflux, and if its a st ripper you want, thats of no use. If you want to add a crude spirit run part to it as well, then you should arrange for the wash to enter a bit down the column, dividing it into a rectifying part and a stripping part. This will give you a crude CM, since the reflux will be controlled by the feed rate.

Might not be a bad idea if you want to concentrate your low wines a bit, but it will still need a spirit run afterwards.

If you want stripping only, you will have the same result just dumping the unheated wash into the column, since the amount of cooling of the column will be the same either way. You add the same amount of cold wash, and the same amount of steam from the boiler. No big difference if its cold wash or preheated wash and reflux you dump into the column, its the same amount of heat needed to heat it to the working temperature of the column. Actually I think the packing will do this heat transfer more efficiently (in used column height) than a heat exchanger.