Natrat Posted March 7, 2014 Share Posted March 7, 2014 I've been thinking a lot about still design, and I was wondering if anyone had ever seen a Petlyuk style column in use for ethanol? We tend to think of our distillations as a binary water-ethanol system, but it's actually a three or 5 or 10 part system if we start to consider the congeners. I think reducing it to a 3 part system (heads-ethanol-water) is most efficient... I was mostly thinking that a large-scale continuous system could use this for a continuous heads draw as well as hearts. anyone seen something like this? Am I way off the mark, or are they as common as dirt in big ethanol plants? Link to comment Share on other sites More sharing options...
meerkat Posted March 7, 2014 Share Posted March 7, 2014 Yes, this is exactly the way it is done in a large scale Neutral Spirit plant. A typical plant would have a stripper followed by a primary rectifier which has 3 off takes (plus minor off takes for fusels etc). The main product stream from the rectifier would be taken off about 5 or 6 trays down from the top while the heads stream would go to the recovery (feints) column. The main product steam is diluted down to 12-20% and put through a hydroselection column and the bottoms from this are fed to the secondary (potable) rectifier where again a 3-way split is made with the heads also going to recovery. I do not have personal experience of using this method for producing character spirits, but I have seen posts here by people who are doing it - although I think they were using more than 3 off takes. Link to comment Share on other sites More sharing options...
Artisan Still Design Posted March 7, 2014 Share Posted March 7, 2014 yes, this is how our continuous system works. we have multiple offtakes, but only 3 are used at any one time. Link to comment Share on other sites More sharing options...
Natrat Posted March 7, 2014 Author Share Posted March 7, 2014 Gotcha...coincidentally, I found a diagram last night that showed this...it lacked plate detail, but had the system of retorts and catchcarry heating and cooling coils. It was from a diageo plant. Steven, what is the footprint of your entire continuous system? Have you done any runs yet, to know what kind of steam requirements you have? Link to comment Share on other sites More sharing options...
agporte Posted March 7, 2014 Share Posted March 7, 2014 I think there is some confusion as to what exactly a Petlyuk Column is, but maybe not. It's not just a column with a side stream taken off. It's a way of taking two traditionally separate columns and turning it into one by adding a dividing wall vertically through a set of trays. It has the advantage of having a combined condenser and reboiler, but the control becomes more complicated (as compared to two columns in series), due the number of degrees of freedom It's actually quote ingenious and could work well for this application. It's like combining the stripper and rectifier into one. Link to comment Share on other sites More sharing options...
Natrat Posted March 7, 2014 Author Share Posted March 7, 2014 agporte, my post may have been a bit vague...the diagram I found was for a true Petlyuk, not just a "system of columns," and that was indeed what I was asking about. Do you know if Aspen Distil supports Petlyuk modeling? I haven't been able to find out, and although I don't have direct access to Aspen, I can have sims run for me. I'm not sure if the increased complexity of build is really worth the effort, but I'd like to figure out how efficient it might be BEFORE putting effort into a prototype or proof-of-concept build. The thermodynamics of the shared wall makes it quite complex to figure on paper. Link to comment Share on other sites More sharing options...
agporte Posted March 7, 2014 Share Posted March 7, 2014 Looks like it has been done before: http://onlinelibrary.wiley.com/doi/10.1002/9781118510193.ch12/summary I'll check and see if I have access to this book through my AIChE membership when I get back to work on Monday. Unfortunately we don't have Aspen or any other complex distillation modeling software. Link to comment Share on other sites More sharing options...
mendodistilling Posted March 8, 2014 Share Posted March 8, 2014 Are you trying to make your own in house NGS Or bourbons? Link to comment Share on other sites More sharing options...
Dehner Distillery Posted March 8, 2014 Share Posted March 8, 2014 Check this out. http://youtu.be/4RxHvrAQA_M I hope I got the link correct. I think it is neat to put two columns in one instead of connected in series. But it comes down to time/money, but they do show the purity is off the chart. I like the idea. A new way of looking at an old idea. I might try to build one when I can find the time. www.redbootstills.com Take care. Link to comment Share on other sites More sharing options...
Dehner Distillery Posted March 8, 2014 Share Posted March 8, 2014 That would be a good question, because you don't need something like that to make bourbon. GNS, now it would do that easy, but you can do that off a standard continuous column currently (if set up correctly). But you would have a two different designs. Take care. Link to comment Share on other sites More sharing options...
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