Continuous Stripping Column Build

We don’t condone the use of Continuous Stripping stills as a method of running 24/7 as this is a commercial setup only .
Home distillers should never leave any still run unattended and Continuous strippers should not be operated for longer periods than a Batch stripping session would typically be run to minimise operator fatigue..

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DeepSouth
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Continuous Stripping Column Build

Post by DeepSouth »

I'm trying to increase production at my distillery and have decided to build a new continuous stripping column. I wanted to create a thread to document some of the build process so that it may be beneficial to other members in the future. I've partnered with my college alma mater and some of the chemical engineering senior students will be helping to design, build, install, test, and run the still for a senior design project.

Summary of the project:

The primary goal of the stripping still will be to perform a stripping distillation on grain-in bourbon and corn whiskey mash. The column needs to be able to process approximately 1000-1200 gallons of mash in a 8-10 hour day. The fermented mash will be approximately 8-10% ABV and will need to be stripped to approximately 25-40% ABV and needs to extract 90-95% of the potential alcohol from the mash. Current whiskey production involves a series of stripping runs in a pot still, and the resulting low wines from multiple runs are combined back together and redistilled in a hybrid pot-column still to produce the finished spirit that will be then barrel aged. The continuous stripping still will replace multiple stripping runs performed with the pot still. The distillate from the new stripping still needs to be nearly identical to that which was produced under the old method to retain the distillery's signature flavor.

A method of mixing the mash will be employed to keep all the grains in suspension prior to being fed into the top of the stripping column. A series of pumps will be used to feed the mash into the top of distillation column and to remove the spent stillage from the bottom of the column. A mash preheater will be used to transfer some of the heat from the stillage to the incoming mash. The distillery currently has access to steam heat, however it is not clean sanitary steam as it contains boiler chemicals. This process steam will be used to either heat a reboiler at the base of the column, or a sanitary steam generator, either of which will be used to produce the vapor that will be injected at the bottom of the column to drive it.

There is a large water cooled condenser that is currently in use on the existing still which can be plumbed in and also used for the continuous stripping column to condense the distillate. The maximum height of the entire stripping column is limited to 13 feet.
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WIski
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Re: Continuous Stripping Column Build

Post by WIski »

This will be a very interesting journey. Thanks for sharing. Hopefully some of the hobby guys can pick up a couple gold nuggets along the way. :thumbup:
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Re: Continuous Stripping Column Build

Post by DeepSouth »

Mass Balance Data.png
Mass Balance Flow Chart.png
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Re: Continuous Stripping Column Build

Post by DeepSouth »

PRO II Simulation Results.png
Updating the build thread a little. The team did a preliminary mass balance of the system and performed a simulation of the stripping column using PRO/II modeling software. The little round symbol with a crooked line in it represents the beer or mash preheater that we will be building.

Stream 1 represents cold mash that is finished fermenting being pumped into the column. Then passing through a preheater that uses the still bottoms to preheat the beer feed. Stream 2 is the clean steam that will be injected to the base of the column. Stream 4 is the hot beer that enters the top of the column. Stream 5 is the low wines that exit the top of the column. Stream 6 is the hot spent stillage leaving the bottom of the still and Stream 8 is the cooled spent mash that has passed through the preheater ready to be used as animal feed.
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Re: Continuous Stripping Column Build

Post by DeepSouth »

According to the calculations and simulations, to strip out 8% ABV preheated mash only requires 3 total theoretical plates. However, theoretical and actual are two different things. According to our research, most stripping plates are only 20-40% efficient, so in reality we'll need maybe 12-15 distillation plates. We'll be using dual flow plates. Basically these are perforated plates with really large holes to allow both the ascending vapor and descending beer to pass through the same holes. There are no downcomer pipes. According to the simulation and mass balance, we'll need about an 8-10" diameter column to process 2.5 gallons per minute. The plates will have 25-30% open area and use 5/8" or 3/4" holes. Since we'll be distilling grain-in, the holes need to be able to pass all the solids without clogging. The plate spacing will be determined after some tests on the foaming and frothing properties of the mash. The university has some device that can be used to test this.
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Re: Continuous Stripping Column Build

Post by DeepSouth »

I've gotten my beer preheater cut and fitted, now I just need to solder it all up. It's basically a 50' long liebig. Cold mash will flow through a 1/2" inner pipe and the hot still bottoms will flow through an outer 3/4" jacket. I've got two flexible impeller pumps that are fitted up with 1/2 hp 3-phase motors that can have their speed modulated with variable frequency drives. One pump will pump mixed up fermented mash through the beer preheater and inject it into the top of the still and the other pump will take the still bottoms and pump it through the outer jacket of the beer preheater and then pump it into tote tanks to be used as animal feed.
20180307_180406.jpg
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Re: Continuous Stripping Column Build

Post by MoonBreath »

Those sight glasses gonna look wild with that mash goin.
Freak some folks out.
Surely that jacket won't ever plug up...shouldn't.
Profile matchn should be easy enough you'd think.
Very well thought out..Watchn with interest.
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Re: Continuous Stripping Column Build

Post by J0hnni3 »

How do the dual flow plates work compared to plates with downcomers? You sound like a guy who might have tested efficiencies, and I’d be very interested if you were willing to share. I’m just getting started with a pot still... still waiting on the ttb, but a column will be next so I’m quite curious. Thank you for sharing the build.
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Re: Continuous Stripping Column Build

Post by DeepSouth »

I've put a picture of the plates below. These were just a mockup out of aluminum as a test of the tooling. The real plates will be made from copper. These were cut on a waterjet. You can see that they have very large holes, 3/4" is what is shown here. Dual flow plates are intentionally inefficient. To strip an 8% mash, you'd need about 3 theoretical distillation stages. We will have 12 total plates. That is because the dual flow trays are at best 40-50% efficient compared to a theoretical plate. That is also a function of the vapor speed, plate open area, and feed rate. These trays are specifically designed for passing large amounts of solids without clogging and are inherently inefficient compared to standard sieve trays with weirs or downcomers.
Plates.jpg
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Re: Continuous Stripping Column Build

Post by Swedish Pride »

Very interesting stuff David, I'll follow with interest.
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Re: Continuous Stripping Column Build

Post by zapata »

Grain in mash through a long 1/2" pipe? Realy? I would have thought that would be plug city. I guess suspension and the right pumps makes more of a difference than I would have thought.
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Re: Continuous Stripping Column Build

Post by MoonBreath »

Beins 3/4" holes, did you go with 10" diameter?
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Re: Continuous Stripping Column Build

Post by DeepSouth »

MoonBreath wrote:Beins 3/4" holes, did you go with 10" diameter?
8" diameter column
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Re: Continuous Stripping Column Build

Post by HDNB »

i too think you are going to have big problems pushing grain through a 1/2 pipe and even more trouble pushing it back through a 3/4 with a 1/2 inside it.

i tried a 3/4 flexible impeller and it regularly plugged and dewatered on the input side.

hell, i dewatered my 2" input yesterday for the first time. it was way easier to unplug than the 3/4 though... :ebiggrin:
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Re: Continuous Stripping Column Build

Post by DeepSouth »

20180313_154142_1.jpg
Lots of parts arrived today. Here's a rough mockup of the column.
Last edited by DeepSouth on Tue Mar 13, 2018 5:27 pm, edited 1 time in total.
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Re: Continuous Stripping Column Build

Post by zapata »

pictures don't work if uploaded through tapatalk. You'll have to open the forum on a normal browser, and use the "upload attachment" tab beneath the full post reply window.
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Re: Continuous Stripping Column Build

Post by DeepSouth »

Just uploaded from browser and edited original post.
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Re: Continuous Stripping Column Build

Post by MoonBreath »

Gotta name for it...

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Re: Continuous Stripping Column Build

Post by DeepSouth »

20180425_165333_1.jpg
20180425_145710_1.jpg
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Re: Continuous Stripping Column Build

Post by DeepSouth »

Got the still mounted to the floor and in place. Still lack a little bit of piping for the various pumps and a little electrical for some of the controls. Maiden voyage is Sunday.
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Re: Continuous Stripping Column Build

Post by Shine0n »

That's purdy!!!

Good luck on the voyage :thumbup:
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Re: Continuous Stripping Column Build

Post by Evil Wizard »

Any updates?
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Re: Continuous Stripping Column Build

Post by richard1 »

Long time since the last post.

Can you update with pictures and performance... especially with respect to possible plate blockage if you had.

Also how to adequately clean all grain from plate
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