seventh son Posted December 3, 2012 Share Posted December 3, 2012 I started out with a 4" column still packed with copper mesh. I'm now upgrading to an 8" column and I'm debating whether I want plates or packing. I realize there are advantages to plates - they are easily adjusted easily cleaned, and they probably offer better control, but I'm concerned that changing to plates could alter the profile of my existing products. Is there any reason why I should avoid copper mesh packing in an 8" x 10' column? Link to comment Share on other sites More sharing options...
John McKee Posted December 3, 2012 Share Posted December 3, 2012 I can offer some better direction if you can provide more info. Until then, here are some things to consider: The mesh isn't going to work well in an 8" column. Mostly due to the strength of that type of material, it will want to crush at the bottom and cause large issues with column performance. Plates are fine, if you have solids in this area of your column. If however, this column is rectifying vodka or other spirits you should consider structured random packing. Cheaper and they have a higher degree of efficiencies. I can can probably be of more help and/or give you some better info if you wish to P.M. me. Cheers Link to comment Share on other sites More sharing options...
nick jones Posted December 3, 2012 Share Posted December 3, 2012 I can can probably be of more help and/or give you some better info if you wish to P.M. me. John, I'd be surprised if I'm the only one on this forum who enjoys the benefit of your knowledge and experience concerning columns, controls, continuous processes, etc. I'd like to make an appeal to you (and everyone else) to keep as much of your knowledge and advice public as possible. Nobody wants to publicize proprietary stuff, and I'm not asking for that, I'd just like to see this thread keep going into more details, which I would find to be very interesting. (if possible, of course) Nick Link to comment Share on other sites More sharing options...
Hewnspirits Posted December 3, 2012 Share Posted December 3, 2012 I'm with Nick....tis the season for giving...information ...I can't believe I just used one of those smiley things......aggghhh! Link to comment Share on other sites More sharing options...
John McKee Posted December 3, 2012 Share Posted December 3, 2012 Nick, Thanks for the kind words. I went offline with Kevin to try to be more helpful. He's in the middle of some upgrades and design decisions (and is running some very cool processes, some of the most high-tech I've seen in beverage alcohol) and I thought it may be more fair for him to share what he wants to about his particular design. However, that being said, we'll be sharing information on our Continuous Flow Stills that we manufacture here in Butte. 1000 gallons of wash every 10 hours, single pass, fully automated. We've been running our distillery off of the prototype for the last 10 months and we're ready to begin selling them to customers in this industry just after the New Year. Until then, perhaps Kevin may be willing to share additional info on our conversation today. Cheers and thanks again for the kind words Link to comment Share on other sites More sharing options...
seventh son Posted December 4, 2012 Author Share Posted December 4, 2012 John, Thanks for your help today. The "cool processes" that John refers to is my "Low-Temperature " process that I have developed, tweeked, and hopefully perfected over the past several years. I have built two small vacuum stills and I'm currently upgrading to a larger 8" column. I didn't invent vacuum distillation - its used entensively in other industries, but adapting and refining the processes was a long trial and error process. The textbooks don't have a chapter on this. The results: I run my stills with a simple hot water heater and I get flavor profiles that are very unique. Link to comment Share on other sites More sharing options...
JohnMcD Posted December 4, 2012 Share Posted December 4, 2012 John, Just wondering if you think an 8"x10' column with structured packing would be capable of hitting 95% after a stripping run. Tough to find that kind of info and I am no engineer. Any thoughts would be appreciated. John Link to comment Share on other sites More sharing options...
John McKee Posted December 4, 2012 Share Posted December 4, 2012 John, Typically, one needs 22 separations steps after a stripping run to adequately rectify upto 95%. These stages can be physical trays or theoretical trays (structured packing). However, if you're not running a continuous still there is a good deal of waste left behind in the column....hold-up volume. Additionally, all separation is properly influenced via good reflux control - perhaps with more effect than column internal sizing/type....meaning that as much attention (if not more) has to be placed to proper reflux design and control than internals selection. Depending on your pot still size, you may be able to effect 95%, but I would suggest that you need at least 2 columns of the dimension you are suggesting above. However, grain-of-salt everyone. I used a reputable and well recognized distillation internals design company to fully flesh out my design. I would not suggest anyone on this forum use my advice solely to influence their design decisions. I'm just a guy like all of you....I make hooch and have a lot of fun doing it. Cheers Link to comment Share on other sites More sharing options...
meerkat Posted December 4, 2012 Share Posted December 4, 2012 Seventh Son, this is very interesting stuff you are doing. I have spent many hours calculating the effects of vacuum, but have never had a chance to actually implement any of it. I really admire your courage and innovation in making this happen. I have a few comments which come out of all my calculations, but probably most of it you will have learnt yourself or from John. Anyway, hopefully some part of this will help you. The pressure (or actually the boiling point) has an influence on the azeotrope composition of alcohols. Most of the flavor elements in potable spirits also have azeotropes with water, and each will react differently to the change in temperature. This is sure to affect the balance of the components and I am not surprised you get a product with a unique character. The ethanol-water azeotrope moves towards 100% as the pressure is lowered. At atmospheric pressure the azeotrope is around 97.2 ABV. At 9 psi absolute pressure (-5.7 psig) the azeotrope moves up to 97.5 ABV and when you get all the way down to 2 psi absolute (-12.7 psig) the azeotrope is close to 99.0 ABV. Of course we cannot get to the azeotrope in a real world column, but it does make it easier to get to 95 ABV if the pinch point has been moved higher. A disadantage of working at 2 psi is that the vapor density, and therefore the vapor velocity, changes by a factor of about 6.5. This makes the column diameters much bigger, and the rules of thumb don't apply any more. You need to get specialist designs for plates and packings at these low pressures (or learn by doing - which probably works better). Another disadvantage of the lower pressure is the lower column top temperature. It would be around 35 deg C (95 deg F) at 2 psia and you would need colder cooling water and bigger condensers. But fortunately the bottom temperature drops as well and as you have said you can boil the column with hot water. At deep vacuums (low absolute pressures) the chemical industry tends to favor packings over trays because the pressure drop per tray is relatively high and can limit how low you can go in pressure. I don't suppose you are working at extreme vacuum, but the tendency is away from trays as the pressure goes down. If you have a problem with packings collapsing because of the height, you can break the packing up into beds with intermediate support plates and redistributors. Petroleum refineries have packed columns of 30 ft diameter and more. Link to comment Share on other sites More sharing options...
seventh son Posted December 4, 2012 Author Share Posted December 4, 2012 Meerkat, breaking the azetrope and producing 100% pure vodka has been on my radar, but curiosity doesn't pay the bills. Most people on this forum understand an azetrope, but most consumers don't. So this product would become a "hand-sell", meaning that every consumer needs to be educated about the benefits of it. Try explaining a complex azetrope to the average vodka consumer! It becomes a very expensive marketing campaign. If anyone out there has that kind of marketing dollars, we should discuss a private label arrangement! Instead of pursuing the ultimate purity of breaking the azetrope, I have gone the opposite direction - pulling through subtle flavors and aromas not possible with conventional stills. The technical details that you talk about are pretty much on the money. Learning by doing is the only way to determine the right combination of vacuum, temperature, reflux, etc. It is not as simple as connecting a vacuum pump to the average still - unless you enjoy watching a very expensive piece of equipment implode! And if you think conventional pots are expensive, look at the cost of vacuum rated pots! No trying to discourage anyone - just letting you know the advantages and disadvantages of vacuum distillation. Link to comment Share on other sites More sharing options...
nick jones Posted December 5, 2012 Share Posted December 5, 2012 1000 gallons of wash every 10 hours, single pass, fully automated. Pretty exciting, John. I can't wait to see the specs! From the sounds of it you're talking about going from mash to spirit in your Continuous Flow Still. Have you considered marketing just a stripping column for a distillery looking to do continuous distillations for stripping and batch distillations for spirit? It seems to me that this would be an ideal way for distilleries with a single pot still to more than double their production while keeping their iconic pot still and not adding the large footprint of an appropriate batch-type stripping still. Just curious... Nick Link to comment Share on other sites More sharing options...
PeteB Posted December 5, 2012 Share Posted December 5, 2012 I did raise the question of a continuous stripping still on this forun some time ago. With my one alembic pot it takes me 3 wash runs then one spirit run, ie 4 days per batch of spirit. If I had a small continuous stripper I could get 4 batches of spirit in 4 days ie. quadruple my production. I shall watch this thread with interest. Link to comment Share on other sites More sharing options...
Artisan Still Design Posted December 5, 2012 Share Posted December 5, 2012 I did raise the question of a continuous stripping still on this forun some time ago. With my one alembic pot it takes me 3 wash runs then one spirit run, ie 4 days per batch of spirit. If I had a small continuous stripper I could get 4 batches of spirit in 4 days ie. quadruple my production. I shall watch this thread with interest. we have a continuous system we are in process of prototyping, hoping to have something to show off at the ADI conference. Link to comment Share on other sites More sharing options...
mmdistilling Posted December 5, 2012 Share Posted December 5, 2012 Seventh Son, Returning to your original question of packing vs plates. From my experience, I have found that good plates are expensive to produce. They can produce say 90% ABV faster than an identical packed column. When I want to produce above that level (to minimize flavor and thus time needed for adsorbtion) I chose a packed column. John mentioned that mesh is not going to work in your size, which I agree with. I too originally ran copper mesh because I read that it had the potential to improve flavor especially in a stainless still. I hate cleaning the copper so I decided to experiment with raschig rings in the same column I was using. I have found the product to be more consistent with the rings and my still maintenance to be much less time consuming. e.g. empty the rings into a a stainless drum and soak in your favorite detergent followed by a good rinse. I'm guessing, since you are operating at a lower temp you have to clean your copper a lot less often though? Link to comment Share on other sites More sharing options...
John McKee Posted December 5, 2012 Share Posted December 5, 2012 Nick, We are considering selling CF stripping stills and will probably have that as part of our product offering when we introduce the family in the New Year. It mostly depends on interest and demand. Cheers Link to comment Share on other sites More sharing options...
seventh son Posted December 5, 2012 Author Share Posted December 5, 2012 mmdistilling, Thanks for the input. The copper mesh is a pain to clean, but I built a CIP system into one of my stills to make life easier. I do break it down and remove the packing every so often to examine and clean it more thoroughly. I'm debating wether to make the switch to ss raschig rings in my upgrade. My old stills have a combination of ceramic raschig rings and copper mesh. Link to comment Share on other sites More sharing options...
bannonjd Posted December 8, 2012 Share Posted December 8, 2012 John: We are about 6 months out from securing our state/federal licenses. Looking at stills. We would like to make a full line of produce including whiskey. We are looking at traditional pot stills from various manufacturers, all steam jacketed. Should I wait a month and consider yours? Will the prices be competitive? What do they look like? Thanks Link to comment Share on other sites More sharing options...
727guy Posted December 20, 2012 Share Posted December 20, 2012 This is a fascinating topic for me, never really heard of azetropes before. I wonder how many of these were ever built? http://www.motherear...az81ndzraw.aspx vacuum distilling Link to comment Share on other sites More sharing options...
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