ProCaps vs. Regular Bubble Caps + Downcomer

Kapea

How many angels can dance on the head of a pin?

FloridaCracker

@Kapea said: How many angels can dance on the head of a pin?

127

FullySilenced

your correct Cracker 12 to the 7th power or is that 1 to the 27th power ... well crap Kapea will have to clarify this one...

happy stillin

FS

:))

FloridaCracker

That's the number that I counted last night. Can't really remember much after that....

Harry

@grim said: I would argue that most users running 4-8" columns are running 60 liters per hour of reflux. So in reality, the slow transition speed has more to do with the specific operating parameters of that demo column, it's not comparable.

Yes. I only wanted to point out that total mixing is not always instant. It's relative to the equipment as you indicate.

But let's examine what's in play here in micro-scale trayed columns...
Good separation is the goal, yes?. Separation is most efficient when contact time is at it's maximum. High reflux conditions like you mention above, are employed to compensate for the low number of trays we use. Low number of trays reduces initial build costs. Nice! The downside is that more refluxing is required which in turn means more re-heating is required, increasing operational costs. There's always trade-offs. No free lunches.

There's a few ways of improving separation. More trays is the obvious one. More recycling (reflux) is another. Longer pathway between entry and exit points in the tray is another. All of these will increase contact between liquid, vapor and heat (the goal). This contact is what drives distillation. Reducing any of these will impact poorly on the still's optimum performance; the product quality; and thus increasing running costs.

For this reason I say that anything that short circuits the contact time (ProCaps do this) Is not good for distillation. But that's my take on it. Ming says it best. See all sections (including the swf tutorials) here...

Smaug

Contact time? ProCaps? The lowly pot still is the least capable if one were to take all of the above at face value and yet we know the pot still in practice makes a wonderful spirit.

Similarly, ADI judges as well as others have concluded that spirits made with ProCaps are quite good, though ADI judges likely have no idea what a "ProCap" is.

Interesting how a "qualified" evaluation can be rendered with and without first hand experience?

FloridaCracker

Holy crap. Guess I shouldn't have derailed the OP's thread with a question about ProCaps. I'm just on the fence and have a short time to decide.

Smaug

@FloridaCracker said: Holy crap. Guess I shouldn't have derailed the OP's thread with a question about ProCaps. I'm just on the fence and have a short time to decide.

No worries there.

They come with a 100% money back guarantee as do all StillDragon components.

Mickiboi

I got my question answered first post. Everything after that has been educational for me and I am learning all the time. I'm glad you asked the question @FloridaCracker, reading @grim and @Harry debating is helping more people than just me understand why things work the way they do.

Harry

Yes potstills do make great spirit. They also have loads of contact time & long travel path. Somewhat moreso than the 1 or 2 inch path & split-second of contact seen with a ProCap. However, eventually the lessons will be learned. And as for "qualified" amd experience. Seems like this forum is much the same as most others...if one dares to offer constructive comment but fails to agree with the status quo, the knives begin a-sharpening. As you wish. I withdraw. Your loss.

Smaug

Status quo? Who's?

You have made a cut and dry determination without one bit of hands on experience with this system Harry.

My apologies to the forum for provoking Harry into taking his ball and going home.

captainshooch

Constructive comments are always welcomed. Flat out saying that ProCaps are not good is a strong opinion and you are entitled to it.

If travel accross the plate and contact is soo important, then how come we are not seeing oval or even rectangular columns to maximize this aspect?

FloridaCracker

@Harry said: Yes potstills do make great spirit. They also have loads of contact time & long travel path. Somewhat moreso than the 1 or 2 inch path & split-second of contact seen with a ProCap. However, eventually the lessons will be learned. And as for "qualified" amd experience. Seems like this forum is much the same as most others...if one dares to offer constructive comment but fails to agree with the status quo, the knives begin a-sharpening. As you wish. I withdraw. Your loss.

I always like hearing ALL sides of any debate. Then I take all of that info, try to process it and determine what will work FOR MY SITUATION. I'm sure that there are no two of us who do everything the same. If I make a bad decision from all information gathered (happens occasionally) then it is MY fault/problem. I deal with it and move on.

Everyone has an opinion. It is my job to determine which advice I will take. That stated, I appreciate all who have chimed in.

Larry, when I travel South in a few weeks, I expect to return with ProCaps.

grim

The single most important factor in beverage distillation columns is flexibility, not efficiency.

In an industrial setting, where efficiency translates to dollars, I can understand the desire to optimize efficiency.

However, optimizing for efficiency requires narrowing of operating conditions to achieve it. Flexibility and efficiency are always at odds. To achieve optimal efficiency means you must be able to operate the column within an incredibibly narrow set of operating conditions. again, fine in an industrial setting where the column will make the exact same thing for 10 years.

This is why you see bubble caps as typical in beverage distillation. They can support a wider range of operating conditions, liquid and vapor loads, etc. Despite the fact that they are not the most efficient tray design. They are used because they can provide a the highest level of turndown of any tray design.

Procap trays are not the status quo, nor is this an echo chamber for the design. Procap is the minority and Harry, it is you that represent the status quo. However, procap approach is to further increase the turndown capability by maximizing downcomer capacity.

Real world tests have shown that procaps can maintain good levels of efficiency, and behave in a way that provides a significant improvement in operating range. They can be run just as slow as bubble caps, and can be run significantly faster.

Is there some efficiency loss due to the short flow paths? Sure, but I will continue to argue that in our operating conditions it is negligable.

There are plenty of bubble tray designs that have such poor hydraulics that large volumes of liquid can simply bypass a cap.

One additional consideration on procap efficiency is a significant increase in active plate areas compared to traditional, maybe upwards of 10-20% more active area.

Your comments on maximum contact time is incorrect. Maybe it's just language issues or semantics. But I believe you mean "optimal" contact time. Maximum contact time means the trays operate as thumpers with zero reflux. Contact time = run time.

Or maybe that's what you mean, and Larrys stacked parasitic thumper design represents the best operating design if you feel "maximum" is required for the reactive distillation process you mention.

Please post references to the literature that supports your position on esterification reactions and tray hold up time. I'm not saying that to be argumentative. I've spent two days searching through journals and can't seem to find any research on this.

Kapea

Well, I guess some walk the walk, and some just bloviate.
Whose loss?

punkin

C'mon guys. We've never been aggressive here before to a member and i don't see why we should start now.

Grim is having a good robust discussion here and doesn't need the pile on.

Kapea

I agree with grim.

Whatever it is that procaps are doing, I like it. I am running bubble caps and procaps side by side, on the 4" level, for comparison - out here in Realville.

captainshooch

Great @Kapea , I have and perhaps we can compare notes when you have some results.
Not trying to be aggressive, just expressing my hands on experince and opinion.

Kapea

I'm still playing with it. There are a lot of ways to change how you run them. Boiler charge, heat input, reflux ratio, number of plates, desired output... I'm just getting started. I love this shit!

captainshooch

Yes, it is why in one of my tests I kept everything equal, and the only variable was the caps...since then I have even ran 4 caps in a 4 inch, and played with different settings on plate fluid level adjusters...still have more playing to do as well.

Kapea

I can see already, with the adjustable downcomers, the height of the extenders will make a difference. Add that to the list of variables.

4 caps on a 4" bubble cap plate @captainshooch? Did you plug the 5th cap hole with a second downcomer?
That's an interesting idea...

captainshooch

No, they dont interchange, made my own plates. 3 caps is plenty, 4 is not really any better.

Kapea

Four procaps on a 4" plate. Got it.

What do you suppose would happen if you removed a bubble cap (1 of 5) on a 4" plate and put a second downcomer in its hole? Do you think you could drive bubble caps at procap speeds without flooding? Would there be a significant loss of enrichment on that/those plate(s)?

Harry

@grim said: The single most important factor in beverage distillation columns is flexibility, not efficiency.

Your comments on maximum contact time is incorrect. Maybe it's just language issues or semantics. But I believe you mean "optimal" contact time. Maximum contact time means the trays operate as thumpers with zero reflux. Contact time = run time.

Harry says... Did you take Ming Tham's content into account? I posted the link previously. Here 'tis content...

Tray Designs
A tray essentially acts as a mini-column, each accomplishing a fraction of the separation task. From this we can deduce that the more trays there are, the better the degree of separation and that overall separation efficiency will depend significantly on the design of the tray. Trays are designed to maximise vapour-liquid contact by considering the liquid distribution and vapour distribution on the tray. This is because better vapour-liquid contact means better separation at each tray, translating to better column performance. Less trays will be required to achieve the same degree of separation. Attendant benefits include less energy usage and lower construction costs.

.

@grim said: Please post references to the literature that supports your position on esterification reactions and tray hold up time. I'm not saying that to be argumentative. I've spent two days searching through journals and can't seem to find any research on this.

Harry says... I've spent 20 years accumulating reference works and applying what they provided to my distilling and other's usage. As requested, support literature (a sample)...

Background: What is Esterification?

Esterification: The process in which an alcohol and an acid are converted to an ester and water.
Esterification is an example of a condensation reaction.
Esterification reactions are equilibrium systems:

Source

Larger esters tend to form more slowly. In these cases, it may be necessary to heat the reaction mixture under reflux for some time to produce an equilibrium mixture. The ester can be separated from the carboxylic acid, alcohol, water and sulphuric acid in the mixture by fractional istillation.

Source

The center cut, which is the bulk of the distillate, has the more pleasant aromas of fruity esters characteristic of rum.

Source (PDF)

One use for blackstrap molasses is alcohol production—traditionally in the manufacture of rum. A new firm, the Louisiana Rum Co., Baton Rouge, is planning a state-of-the-art facility to produce rum from Louisiana molasses. After clarifying the molasses to improve yield, it is fermented with a special yeast that produces glycerin and alcohol (7). Distillation separates the alcohol portion, which is subjected to a new proprietary aging process. The new process produces a drinkable rum in just one day; the traditional process takes two years. However, the rum will be aged in oak casks for at least six months to develop its color and flavor. Then the rum is diluted with water, filtered, and bottled.
The distillation residue, called stillage, is the source of many of the flavor components of rum. For example, with the use of native and added bacteria, stillage produces acetic and lactic acids. Further fermentation produces caproic and succinic acids, which are esterified to ethyl caproate and ethyl succinate. These esters are important flavor components along with certain aldehydes and fusel oils (chiefly amyl alcohols). “Light” and “heavy” rums are produced by controlling the relative amounts of these components (7).

Source

The ester content of rum varies from 4 to 64% w/v, with ethyl acetate typically being the predominant ester. The ester content in rum is related to many factors. The esters formed during fermentation are related to the distribution of esters between the yeast cells and in the medium, and to factors affecting ester concentration. When yeast is present during distillation, the content of long-chain carboxylic acid esters derived from the yeast cells increases. The ester content of the beverage of rum also depends on the yeast.

Temperature affects the rate of ester formation in the medium (Nykänen, and Nykänen 1983). 2-ethyl-3-methylbutyric acid has been determined in rum and is believed to come from 3-methylbutyric acid, a compound found in molasses (Lehtonen et al., 1977). During distillation the middle aroma fraction consists of esters from ethyl hexanoate to ethyl laurate, esters of long-chained carboxylic acid with the acid part longer than 12 carbon atoms belong to the heavy aroma fraction of rum (Nykänen and Nykänen, 1983). Table 2.12 includes some of the most common esters of aliphatic monocarboxylic acids that have been identified in rum.

Table 2.12 Esters of Aliphatic Monocarboxylic Acids in Rum

Ethyl formate           Ethyl valerate           Ethyl undecanoate
Methyl acetate          Hexyl acetate            Isobutyl dodecanoate
Ethyl acetate           Isopentyl propionate     Isobutyl duodecenoate
Isobutyl formate        Isobutyl butyrate        Ethyl laurate
Ethyl hexanoate         Isopentyl decanoate      Propyl acetate 
Ethyl propionate        Ethyl heptenoate         Ethyl mysistate
Isopentyl formate       Isopentyl butyrate       Isopentyl laurate
Isobutyl acetate        Ethyl heptanoate         Ethyl pentadecanoate
Butyl acetate           Methyl octanoate         Methyl palmiatete
Sec-Butyl acetate       Phenethyl acetate        Phenetyl decanoate
Propyl propionate       Isopentyl valerate       Ethyl-9-hexadecenoate
Ethyl isobutyrate       Ethyl octanoate          Ethyl palmitate
Ethyl butyrate          2-Methylbutyl hexanoate  Propyl palmitate
Isopentyl acetate       Isopentyl hexanoate      Ethyl linoleate
Isobutyl propionate     Ethyl nonanoate          Ethyl oleate
Propyl butyrate         Methyl decanoate         Ethyl stearate
Ethyl 2-methylbutyrate  Ethyl decanoate          Isopentyl palmitate
Ethyl isovalerate       Isopentyl octanoate 

Source: Nykänen and Suomalainen, (1983).

Source: Rum Aroma Descriptive Analysis - Master's Thesis by Maza Gomez, Sabina

File: PDF

About Ms Gomez:
Sabina Maza-Gomez won the 2nd place of the 2001 Graduate Paper Competition, Biotechnology Division at the 2001 Institute of Food Technologists (IFT) Annual Meeting, New Orleans, LA. The title of the paper is “Increased Ester Production in Rum Distillates Using Propionibacterium thoenii and Clostridium propionicum Stillage fermentations” by Maza-Gomez, S., Kampen, W. H., and Prinyawiwatkul, W.

Footnote:
Harry says...
I'm pleased to see there are some on here starting to think reconfigurations and making comparisons. Follow-up reports will be an eye-opener for others.
I think that's enough 'grist for the mill' from me for now.

FullySilenced

Geez Harry ... I love it when you get going .... :D just more food for though

captainshooch

@Kapea I do not know what 2 downcomers would do on a standard cap plate because I have never tried it. I think others have, maybe they can chime in.
I do know that I have been running and testing the ProCaps for 8 months, fact I was the first one in the USA to run them, and I have plenty of hands on experience with them. I have seen the results first hand and have been providing feedback and reports on my findings.

Kapea

I have been running bubble caps for a little over a year now. I happened upon a very good deal on procaps recently that I couldn't pass up. So now I am working with them too. All on the 4" scale for now. So many possibilities present themselves when you have "Lego blocks" to build with. I enjoy reading others' real world experiences with the same blocks I have to work with.

Then there's my new GB4 and my fascination with gin, and other infusions... @crozdog's GB4 operations guide has been very helpful in getting that going well right from the jump. That and the gin tastings and seminars I went to in Seattle last spring.

mikew

Thanks Harry... that's some interesting reading.

Mickiboi

Come on guys, kiss and make up please. I was enjoying reading your different opinions and getting more educated, but I'm starting to not enjoy coming here and it's not supposed to be like that. That shit of ganging up on someone is reserved for the other sites which I left precisely because of that reason. If I leave here I have no where else to go. Please don't make me homeless. :(

grim

Harry, thanks for the references, I appreciate you taking the time to post them up.

I'm familiar with esterification, specifically those reactions that act on fermentation byproducts which are the critical precursors for the reaction. However, you made a comment earlier that tray reaction time was critical in the development of ester formation. It's this point that I am looking for information on:

The longer the path of liquid on the plate, the more contact time afforded for vapor, heat and liquid to do its thing (separation & ester formation).

You drew a direct relationship between the tray hydraulics and ester formation.

While there are heat-mediated reactions taking place, and esters that are taking place as a result of refluxing/condensation, these reactions are not unique to trayed columns, and will take place within the still body itself, regardless of type. Some would argue that a pot still would produce significantly more esters and ester precursors than a trayed column (I don't know what they base their position on either). None of the references you posted provide this background. You'll get similar ester production across a range of still designs, even radically different approaches, pots, thumpers, packed, and all style of plates.

Look, I'm all for a passionate discussion on a topic, especially if it advances everyone's knowledge about a particular point. If I've turned off anyone based on my style of discussion, I apologize. I'm naturally somewhat argumentative and passionate, and there is seldom a situation where I don't question the common understanding/perceptions. I can understand that how from that outside, that might be viewed as just coming off as a jerk. That's never my intention. You don't break new ground until you push limits, sometimes that's not comfortable.

I've enjoyed this thread immensely.