Continuous rectifying steam column

[Steamer]

Hi guys, nice forum you've got going here. Glad I found it, and TY Uncle Jessie:) Lots to learn, and perhaps a bit to share

Here's a short introduction, since this is my first post:

I'm from Scandinavia and have some experience with automation and electric work, aswell as with welding and fabrication. I have built 12-15 TIG welded SS stills for friends, private customers and myself during the years. Most of them simple CM units based on the "labmaster" design with straight coolant tubes intersectioning the column, but I've done some trials and experiments on a steam column aswell.

I have three stills, all of them unused atm, and they have all been hibernating in storage for some years now...

But circumstances and too much leisure-time, aswell as finding this site, got me thinking about old projects and unresolved challenges again...

Disclaimer:

For me personally, the building and testing phase of the equipment is much more interesting and fun than bringing finished product to the market; my equipment is scaled to the size that it is for several other reasons than just producing large volumes:)

That said, I work exclusively with 3" SS columns, and my goal is to increase all aspects of quality, speed, yield and economics with a minimum of effort. The goal is to obtain a neutral liquer, possibly in substantial quantities, with a minimum of effort.

And again, my interest is not directed towards the marketing or possible sales of the end-products, but mainly to learn and hone my skills - both for today - and perhaps for an oil-depleted and much different tomorrow...

So here we go:

I have a 200l PLC-controlled all-stainless batch reflux column still, and a steam powered continuous reflux still that behaves best as a somewhat continuous refluxing stripper. Both are 3" SS columns and built by yours truly.

I would like to use my (upgraded and rebuilt) existing equipment to obtain an absolutely neutral spirit. Column heighths, head designs, electrical control and physical manufacturing are not an issue; I have some experience as I stated earlier.

The challenge to the forum is to help me out with the theory, science, experience and general advice. The return will be a fully documented thread where we develop a two-stage process, with stripping-runs done in a continuous steam-powered column, and distillation for cuts done in the large batch-boiler.

I've had some success with a process where the wash is stripped in the continuous steamer, and then making the (heads) cuts in the batch still after diluting the strippage to around 30% ABV with water. By this procedure the product is very clean out of the steamer with extremely little tails left, but most of the heads still needs to be excluded by making cuts in a later distillation in the batch-still.

I believe that the tails and much of the other lower flavoring contaminants mostly disappear with the dilution factor and the short heating times cooking on clean water-steam gives, as compared to using the sour boiled fermented wash as the propellant through the column.

My systems in fact works rather well - but could obviously need a modernisation, refinement and an upgrade. And that's why I'm here:)

I'd like to reduce the maintenance and increase the quality of the output through automation and design. Height is not an issue as said; I have about 5,5meters or 18ft of ceiling available in the shop.

Today, the shortcomings are mainly a lack of speed and a low ABV (around 70%) output from the stripping steamer, and issues with a desirable sharper separation of heads from the batch still.

Help me out here and let's have an informative discussion, and a nice build-and-test-thread:D

[Steamer]

My continous steam still is based on practical experiments with several designs and drawings. I ended up dimensionally with a design very close to this one regarding the column itself:

http://homedistiller.org/equip/cont" onclick="window.open(this.href);return false;" rel="nofollow

Question to Admin:

This link are to the best of my best knowledge not available through the menus in the main site - how come?

However.

The main difference here is that I boil and produce steam on clean water. Lifting the alcohol through the column with clean steam is an enourmous advantage IMO, but it presents a lot of it's own challenges...

I can not currently feed my 2Kw 3" steam column more than 9l of wash an hour before it chokes (or stops producing). With 8 mm raschig-rings and no insulation, my hope is that it's possible workload might increase with insulation and Amphora-mesh? I can change every aspect here besides for 3" diameter, and I'm hoping for 20l of wash an hour.

[minime]

I think your goal of 9 liters of wash per hour on a continuous stripper is pretty low. The Scandinavian distiller Riku has already developed an automated still system documented in his book Designing and Building Automatic Stills. It could easily be adapted to a 3" column. It's available from the Amphora Society website.
http://www.amphora-society.com/" onclick="window.open(this.href);return false;" rel="nofollow

You might be interested in this thread as it was inspired by reading Riku's book and an Aussie distiller Hookline.
http://homedistiller.org/forum/viewtopi ... =17&t=7647
I am also currently testing a LM 3" column in the following thread.
http://homedistiller.org/forum/viewtopi ... =17&t=8376

Good luck on your journey and welcome to the forum.

[snuffy]

It looks like you are asking several questions at once. They are interrelated, so none of them have simple (or even single) answers. So in an attempt to sort things out a bit, I'm breaking them out as much as possible. A schematic diagram with some dimensions, observed temperatures and power levels would help in moving the discussion along.

1) Choking (aka flooding) - this is when a column is overloaded with liquid and leaves no space for vapor. There can be several causes: feed temperature (more about that later), type of packing, amount of reflux, etc.

1a) Column capacity with rings vs mesh - the short answer is rings fill more space and leave less voids, so the column will flow a greater volume with mesh than rings.

2) Throughput - this is a complex issue. For starters, I have to answer your question with more questions: What is the temperature of the feed when it enters the column? How much reflux are you running? What is the temperature of the steam coming in?

3) Power level for a 3" column at max reflux is generally 80% of flooding. It will vary with packing. If you are going for max reflux, see Riku's book that minime mentioned. The accepted target is around 20"/sec vapor velocity in an empty column for mesh, less for other packing materials. One thing that would have a huge influence is the feed temperature. If you use preheating from the spent wash, you will get more power in the column and less leaving with the wash -- which is a lot. My extremely rough calcs put about 80% of the heat energy for 8%abv wash into the spent wash and 20% into the ETOH vapor. Others' mileage may vary. The calcs are messy because of assumed ranges, so it could be 90/10 or 60/40- I'm sure the uncertainty is at least one order of magnitude. In the future, I'm thinking about running some controlled experiments to narrow the uncertainty.

Some general comments: 70% abv is very high for stripping. This suggests you're running a fair amount of reflux. Because this is a continuous operation, you will have a constant level of heads coming though and most of the tails, though some will exit with the spent wash (depending on temperature.)

Sorry for the lack of short answers.

[manu de hanoi]

im working on a continuous steam injection still, do you have pics/designs of your current setup in order to spark the debate ?