Talk:Distillation

Select moot sections have been moved from here to Talk:Distillation/Archive 1.

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Improvement Project

This and many other chemical, biochemical, biotechnology articles are pretty pathetic. Join the new improvement drive at the above Wikiproject. I am new at wikipedia and need a lot of help! so HELP!!!!

glossary of terms

is it possible for a liquid with a constant b.p not to be pure?

If you are referring to a constant boiling point during the process of a batch distillation, and I understand your question correctly, I believe the answer is yes--try investigating azeotropes; this might be the concept you are looking for. Azeotropes are also discussed briefly in this article.--GregRM 03:14, 22 March 2006 (UTC)

Someone's messed with this page

I just started reading it and someone added in "You know what I mean yall"

A Distiller is also an Adobe term for the process of changing files into PDF files. SHould this be included here? I don't know enough about it to do it myself but came looking for an explaination so may be it should at least have a note and a link? Thanks

69.36.1.158, first of all, you should always sign and date your comments on a Discussion page. If you end your comment with four tildes like this ~~~~, your comment will automatically be signed and dated.

As for mentioning the Adobe term "Distiller" in this article on Distillation, I don't think it is needed. The article does not include the word "distiller". If it did, then it might be appropriate to mention the Adobe term and/or create a disambiguation page for the word "Distiller". But since that word is not included in the article, I don't think that any disambiguation is needed as yet. - mbeychok 22:58, 11 September 2006 (UTC)

Added a discussion and image of industrial distillation towers

I just added a discussion and an image of industrial scale distillation towers. In my opinion, the article was too heavily focused on laboratory distillation and whisky stills. - mbeychok 23:14, 25 March 2006 (UTC)

The terms "still" and "pot" are rather archaic

The terms "still" and "pot" in reference to distillation equipment and reboilers may still be used in bench-scale lab work or perhaps even in pilot plant scale. But industry (with perhaps the exception of some whisky distillers) rarely uses those terms today. "Distillation towers", "fractionators", and "reboilers" are the terms almost universally used in petroleum refineries, petrochemical plants, natural gas processing plants, and other industries. I really think "still" and "pot" should be removed from this article. - mbeychok 06:12, 21 April 2006 (UTC)

Vapor pressure or boiling points?

Which is more correct ' Distillation is a method of separation of substances based on differences in their boiling points.' or ' Distillation is a method of separation of substances based on differences in their vapor pressures.' ? -- ∞Dbroadwell 19:32, 4 May 2006 (UTC)

As one who has designed dozens of distillation columns in oil refineries, petrochemical plants and natural gas plants, most process design chemical engineers would say "... based on their relative volatilities."

But if you tie me down to just the two options you asked about, I would say "... based on their boiling points." The problem with that is: do you mean their atmospheric boiling points or their boiling points at some specific operating pressure? Same problem with vapor pressures: do you mean vapor pressure at any temperature or at some specific temperature?. _ mbeychok 20:27, 4 May 2006 (UTC)

You're right about that describing distillation using vapor pressures is a roundabout way to refer to their relative volatilities. But I think that there's no confusion with respect to vapor pressure; a given mixture results in specific vapor pressures. --Vuo 22:39, 4 May 2006 (UTC)

Commentarry from WP:RD

Offhand, and as a non-expert, I'd say they're both roughly correct, but the difference in vapor pressure is a bit more precise. In my understanding, what matters most is the difference in vapor pressures at the operating temperature of one's apparatus ; but realistically speaking, one probably designs an apparatus to take into account the entire phase diagrams of the substances. Melchoir 20:10, 4 May 2006 (UTC)

Both are just as correct, because vapor pressure and boiling point are not independent properties. Another way of saying it is that the seperation is due to the differences in Activity coefficient. (lousy article, though) --BluePlatypus 20:35, 4 May 2006 (UTC)

And if both are equally correct, we should use the simpler explanation, which is the difference in boiling points. That will make it easiest to understand by the widest possible audience. StuRat 23:21, 4 May 2006 (UTC)

Distillation Structure

While this article has quite a bit of rather complete data, it seems to end abruptly and is trying to answer all of the topics about distillation in one place. Idea: move more towards a featured article format by making sure that the data here, is represented in each of the sub-articles and making this one more of a 'summary' type of thing. Commentary? -- ∞Dbroadwell 14:52, 5 May 2006 (UTC)

I think this article is getting a bit jumbled - maybe it should have a bit of a restructuring shake-up?

my suggestion is:

1 History

2 Theory

3 Types of physical distillation

3.1 Simple distillation

3.2 Fractional distillation

3.3 Short path distillation

3.4 Vacuum distillation

3.4.1 Air-sensitive vacuum distillation

4 Types of Chemical distillation

4.1 Azeotropes

4.2 Steam distillation

4.3 Reactive distillation

4.4 Destructive distillation

5 Applications

5.1 Distilled beverages

5.2 Industrial distillation

5.3 Laboratory distillation apparatus

6 See also

7 External links

8 References 9 Gallery

Also there is quite a few redundant bits where distillation is redefined, and could be deleted.

your views please!

Quantockgoblin 09:16, 12 October 2006 (UTC)

Quantockgoblin: I agree that some re-organization would be useful. I strongly disagree with your making a distinction between what you call "physical distillation" and "chemical distillation". In other words, your sections 3 and 4 should be combined into one section entitled "Types of distillation". I also think that section 5.3 shoul be eliminated completely ... this article already has altogether too much emphasis on laboratory glassware and laboratory setups. Short path distillation and the Kugelrohr apparatus are covered in two section of the article as it now stands. - mbeychok 16:50, 12 October 2006 (UTC)

Mbeychok, thanks for your comments. I'm not too hung up on the idea that we need separate sections 3 and 4, I'm just trying to make sense of the various types of distillation. So maybe just a re-ordering of a combined section 3 and 4. Although, I can't help but think there is a bit of a distinction between separating mixtures as opposed to using distillation as a means for driving chemical reactions. I agree 5.3 is a little redundant, but I do think application of distillation in the lab will be of interest to readers.Quantockgoblin 12:51, 13 October 2006 (UTC)

Quantockgoblin, thanks for letting me know that we are pretty much in agreement. I would just point out that using steam in steam distillation is not a means of driving chemical reactions. The steam, in effect, simply allows the distillation to occur at a lower temperature. Nor do I see how destructive distillation is a means of driving chemical reactions ... in fact, I am not sure that it is a distillation process. I think the more appropriate name is pyrolysis. I agree that lab distillation is of interest to some readers, but there are many, many readers who are also interested in the tens of thousands of industrial distillation towers worldwide and I still believe this article does not have a proper balance between industrial and lab distillation. Regards, - mbeychok 15:43, 13 October 2006 (UTC)

Mbeychok, great, I guess we just need to do the reorganisation then! Just to follow up on your last comment a little. You are correct that pyrolysis is not a distillation technique, although the products of the pyrolysis reaction are often distilled off. However, many chemical reactions exist in an equilibrium and that equilibrium can be driven to one side by distilling off the most volatile component. A classic example would be to distil water from a equilibrium mixture of an alchol and an carboxylic acid to make an ester. This is certainly an application of distillation but is it distillation as such? In terms of balance, we probably need at least a third view? The only other option would be to split the article in some way, 'industrial scale distillation' vs ??? Quantockgoblin 17:12, 13 October 2006 (UTC)

Quantockgoblin, I don't think we need to split the article ... we just need less laboratory chemistry orientation. Your above "classic example" of distilling water from an alcohol and carboxylic acid mixture to make an ester is an example of what I mean .. it isn't really sticking to the definition of distillation in the opening sentence of this article, namely Distillation is a method of separation of substances based on differences in their volatilities. Your example is, in my opinion, purely a chemistry subject. It is not the layman's definition of distillation nor is it the engineer's definition of distillation. I think we should keep the total readership in mind and somehow achieve a balance between laboratory chemistry and the large world of industrial distillation. I do agree with you that we should wait until we've heard from at least 6 or more people. With that, I will bow out of this dialogue until we have heard from many others. - mbeychok 18:53, 13 October 2006 (UTC)

Are you certain that water is distilled off, not the ester? Usually for short chains, the ester will be more volatile. Another example would be the use of a Dean-Stark apparatus to remove water for the same purpose - to drive the equilibrium. --Rifleman 82 17:21, 13 October 2006 (UTC)

I wondered if anyone would come back with that ... it really depends on the size of the acid/alcohol! But the point is the same, one component is removed to drive a reaction Quantockgoblin 17:57, 13 October 2006 (UTC)

Reason for changes

Simuulation is not "necessary" for designing fractionation columns, so I deleted that wording. Such columns were designed using plate-by-plate calculations done by manual calculations for many years before we even had hand-held calculators and computers. To preach a bit, what is "necessary" is for engineers to learn how to do such calculations manually because then they will be in a much better position to evaluate whether their "black box" simulation model is providing credible answers.

I also provided a better definition of distillation trays (or plates) and how their efficiencies compare to theoretical equilibrium stages.

Finally, I deleted the statement that distillation columns might need four times more trays than theoretical equilibrium stages. It is quite rare for distillation plates to have an efficiency as low as 25%. Most trays in most distillation systems have efficiencies in excess of 60%. In any event, I don't think there is anything gained by attempting to characterize the "typical" range of efficiencies. Distillation plate efficiencies are a function of the type of plate, the design of the plate, and of the separation system itself (i.e., feed composition, operating temperatures and pressures, etc.). - mbeychok 23:22, 5 May 2006 (UTC)

Re: (OT) Engineering Soapbox; No kidding. If you had any clue how few of the engineering students could grasp the subleties multi-demsional integration or do math without calculating you might be suprised and I'm a student myself! But, Back On Topic; I'll do some writing up of the 'homebrew' low pressure distillation system and about solar distillation, which is a similar low pressure low tech type of thing. I'd like to see this article refactor into something that reads less like a jointed report and more like a encyclopedia article, but my own knowlege of the topic is a bit low to handle that at the moment. -- ∞Dbroadwell 01:26, 6 May 2006 (UTC)

origins of distillation

I'm pretty sure distillation came from the Arabs (in the process of making perfumes; thus al-cohol), but I'm not sure of a particular source for this. Anyone know any more about it?—The preceding unsigned comment was added by 198.144.78.126 (talk • contribs) .

Distillation was probably first used by the ancient Arab chemists to isolate perfumes. Vessels with a trough on the rim to collect distillate, called Diqarus, date back to 3500 BC.—The preceding unsigned comment was added by 219.65.138.47 (talk • contribs) .

disadvantages

Does distillation have any disadvantages other than the fact that the heat can be detremental to the materials within

Disadvantages compared to what? And please sign your messages. - mbeychok 02:44, 17 September 2006 (UTC)

One of the main disadvantages of distillation is that it is quite dangerous! Inexperienced people can set up distillations as sealed systems which can lead to a very dangerous explosions due to the build up of pressure in the system, and if flamable solvents are used, a fire as well. also, distillation is often used in conjunction with chemical drying agents to dry solvents, in some cases this can lead over time to build up of dangerous and explosive by-products.

Distillation is also not always the most efficient route to remove impurities. For example people often try to remove trace impurities that have high boiling points e.g. DMSO from solids by use of vacuum distillation techniques which can take days. Often it is better to add the desired solid to a column (column chromatography) and wash the DMSO off with hexane, then remove the desired solid from the column with a more polar solvent like DCM. Quantockgoblin 09:57, 9 October 2006 (UTC)

I would say that the first and second points about the dangers of stills do not apply when trained and experienced personnel are concerned. But bearing in mind the number of distillation accidents...

Why would you want to send your solid through a column? Why not wash with water and pump dry? Water should come off much more easily under a high vacuum than DMSO. --Rifleman 82 13:21, 9 October 2006 (UTC)

Indeed, with regard to point 1 & 2, when trained and experienced personnel are concerned accidents should not happen but they do! In fact, I heard of quite a few post-doc chemist being involved in still accidents/fires or near misses. You are correct that a with proper training and vigilance accidents should not happen, but that is about managing the real risk!

Not all compounds are water soluble or stable (or as you might then point out, stable on all column media either), also water (like DMSO) can be very hard (/slow) to remove on even a very good pump - depending on the desired compound. I've seen people wash with water, vap down to remove DMSO. Then to remove trace water they zoetrope with toluene, vac down (repeat a few times). Then add EtOAc to remove the Toluene and so on. A simple filtration in effect through silica can be a lot less fuss. But in a way, your point is the same as mine, straight distillation is not always the best way or the fastest way to remove high boiling impurities without and intermediate step.

I thought the question posed by the original editor was to highlight any disadvantages of distillation, my role was not to debunk distillation, but was at least to suggest that it is not always the best route to remove liquid impurities - well not quickly anyway! Quantockgoblin 14:30, 9 October 2006 (UTC)

Image Thumbnails

Hi Mbeychok

I see you've been painstakingly adjusting the image widths to fit the article together. Thanks for your effort. A point though - all your work will be for naught if the next user doesn't use a full screen window, uses a different browser, uses a different screen resolution, default font, etc. Perhaps we should just leave it at thumb without setting the number of pixels? This is especially good for people using PDAs or similar who have very small screens.

As an aside, how about contributing your expertise on industrial distillation to this article? --Rifleman 82 05:56, 9 October 2006 (UTC)

Rifleman, as you noted, it is virtually impossible to cater to every one's display screen and I agree. What I did was try to cater to the vast majority, like myself, who use Windows XP as their operating system and Internet Explorer as their browser. It is my belief that majority of Wikipedia users are not using Firefox browsers or using UNIX or other advanced operating systems ... and PDA or cellphone users are certainly only a very, very small percentage.

As for your other point about industrial distillation. In the 7 to 8 months that I've been active on Wikipedia, I have created over 40 new technical, engineering article and made major contributions to another such 40 articles. During that time, I have learned that large majority of devoted and very active Wikipedians are university undergraduates or post graduates, and the number of young chemists and young physicists (with no real world experience) far outnumber the very, very few experienced engineers who contribute to Wikipedia. I am not trying to denigrate the students ... I am merely stating the factual situation that currently exists. This distillation article and most of the ten or so other distillation articles (listed in the "See also" section of this article) are quite obviously heavily oriented toward laboratory distillation as evidenced by all of the images of glassware setups in the ten or so articles. As one pertinent example, in my 50 year career as a chemical engineer (during which I designed half a dozen oil refinery vacuum distillation towers with diameters exceeding 4 meters), neither I nor anyone I worked with ever heard of a laboratory Perkins Triangle or Rotary Evaporator vacuum distillation setup. In other words, I and the young chemistry students who wrote those ten articles just don't live on the same planet. If you will look on the History page of this article, back in about the last week of March, I wrote the section on Industrial Distillation which has since been relegated to the last sub-section in the article. It would be a losing battle for me to try and re-orient this article to truly represent the tens of thousands of large industrial applications of all types of distillation that exist in the real world outside of university and research institute laboratories. So I've turned my efforts, as much as I can, into areas not dominated by young chemists, physicists and mathematicians. Please don't interpret this as a complaint or a rant ... I enjoy working on Wikipedia and this is only a realistic, pragmatic statement of the facts as they now exist in Wikipedia. - mbeychok 07:04, 9 October 2006 (UTC)

Hi Mbeychok

What I meant to say was that, if you did not set an image width for each thumbnail, the image width will be set either at a default value, or at an appropriate size chosen by the user (in the settings). By forcing an image width, the thumbnails will no longer resize according to the user preferences. Having the image conform to the user preferences, I would expect, would fit even more of the users most of the time.

As for industrial distillation - I see your point of view on the uphill task. Reading your contributions I felt that is your forte, and it would be nice to have some balance, and make the distillation article even more complete. Thanks for your comments all the same. --Rifleman 82 08:11, 9 October 2006 (UTC)

Rifleman, explaining the large-scale, continuous fractionation distillation towers used in industry just cannot be done in a few paragraghs or even a few pages. It takes a textbook to do a thorough job. It would require explaining what is meant: by the vapor-liquid equilibrium data (VLE) of multi-component feedstocks; what is meant by equilibrium stages; what is meant by bubble-cap distillation trays or valve trays or grid packing used in place of trays; what is meant by side-draws for simultaneously and continuously withdrawing fractionation products at various points along the height of a fractionation tower (i.e., not all products are withdrawn from the top of the tower); what is meant by external refluxing; what is meant by reboilers (i.e., the heat input sources such as fired furnace reboilers, horizontal kettle reboilers, vertical thermosyphon reboilers, etc.); what is meant by pump-around reflux; and dozens of other items for which Wikipedia has no existing articles that can be linked to for explanations. If you have access to a good library, read the book described in Distillation Design or the pertinent sections in Perry's Chemical Engineers' Handbook. - mbeychok 19:30, 9 October 2006 (UTC)

Maybe there should be a separate article on Industrial scale distillation or some similar title. Realistically, I doubt I'll ever get around to writing such an article, but maybe someday someone such as mbeychok may muster the ambition to write such an article. I'm both a chemist and chemical engineer and I know both lab chemists and chemical plants use distillation in their own ways. Rotary evaporators are apparati which use a simple form of distillation in a vacuum or partial vacuum and are used by many chemists, so they are worth at least mentioning in this article. I have not heard of a Perkins Triangle distillation and I suspect that section could be shortened. Wikipedia is a general encyclopedia written for all kinds of people. I think the simple chemist's distillation diagram is easier for the layman to understand than more complex industrial processes, so I prefer that a chemist's diagram stay in there. Should the average person ever set up a distillation, they are more likely to do it the chemist's way than like an industrial scale process. I would prefer to have a Laboratory distillation apparatus subsection in this article, at least a short fundamental one. Nevertherless, it is also worth discussing the large-scale industrial aspect of this topic. H Padleckas 06:04, 22 October 2006 (UTC)

Major rewrite?

Hi all, I have just started an offline rewrite of the article, I just want to see if I can get it into a higher-level article. I guess this article should have a layout like articles as organic chemistry, inorganic chemistry. I need some help with getting a full list of all versions of distillation that have their own main article. Please bear with me on this, I'll be back in a bit. --Dirk Beetstra ^{T C} 10:22, 22 October 2006 (UTC)

I resorted the article and tried to add some small things (well, mainly copied from main articles), I think that industrial distillation should have a similar faith, there should be a paragraph comparing at least the differences between industrial, laboratory scale and beverage distillation (may have a go at that later), and the beverage distillation should be extended (or is there a main for that already?). --Dirk Beetstra ^{T C} 11:31, 22 October 2006 (UTC)

Distillation, distillation.— Preceding unsigned comment added by H Padleckas (talk • contribs) 22 october 2006, 15:35 (UTC)

Luckily I checked that in the main document before I saved.  :-) --Dirk Beetstra ^{T C} 15:12, 22 October 2006 (UTC)

Although most small-scale distillations are effectively batch distillations, the Batch distillation article is obviously written to discuss industrial-type distillations. Perhaps Batch distillation could be combined with a very stubby article called Continuous distillation (which could be substatially expanded) to form an Industrial scale distillation article, or an article with some similar title. H Padleckas 16:38, 22 October 2006 (UTC)

Nice to know that this article is being worked on, probably as the COTM. Hope you guys don't think I'm throwing the work to the group and slacking off. I felt that there was little more knowledge I could contribute, which is the reason for my lack of recent edits. Hope you like the pictures though. Serendipity. I don't usually do distillations. --Rifleman 82 16:45, 22 October 2006 (UTC)

I can imagine there are quite some industrial methods as well (I don't know enough about industry to make a list of them), which could get a similar way of describing as for the laboratory scale distillations (in this article). I think, since batch and continuous are obviously opposite, and their way of thinking is distincively different, that they should be separate. I put batch distillation in the industrial section, but maybe that is not the right place. Maybe they should be mentioned in the paragraph describing industrial/laboratory/food distillation? --Dirk Beetstra ^{T C} 16:51, 22 October 2006 (UTC)

Two separate categories are needed

This is in regard to the above discussion about a major rewrite. Trying to cover both laboratory distillation (of importance to chemists) and industrial distillation (of importance to engineers) in one article is, in my opinion, a tremendously difficult undertaking. It is akin to trying, in one article, to cover residential home design and the design of skyscrapers of 100+ floors high.

What we need is to have two separate categories. One should be Category:Laboratory distillation and the other should be Category:Industrial distillation. I think that is the only way to get cohesive, well-organized articles without continually trying to reconcile the different viewpoints of the laboratory chemists and the engineers. - mbeychok 19:45, 22 October 2006 (UTC)

I partially concur. The different subjects (the different ways of distillation) should be split out in different articles (and also for the categories, I will have a look later), but this article should attempt to find the general principles available in both (as in your comparison, tell about the brick and concrete, and tell about the major differences), and then point to the different ways of distillation (in a way I now attempted for laboratory distillation, which also encompasses a huge field of similar, but different techniques). Could you give a try and make a course list of different industrial distillations? Cheers! --Dirk Beetstra ^{T C} 19:55, 22 October 2006 (UTC)

Dirk Beetstra, I will provide a list of industrial distillation types within the next day or so ...right now, I am about to take off for the rest of today with my wife for a movie and dinner. I fully agree with you that we need separate articles but I feel that they must also be in separate categories. I also don't think that a laboratory distillation article needs any discussion at all of industrial distillation ... nor does an industrial distillation article need any discussion at all of laboratory distillation. That is what "See also" sections are for. - mbeychok 22:02, 22 October 2006 (UTC)

I can concur with that, but this article is about distillation, that is, the technique, and that is the same, both for laboratory ánd for industrial distillation. If you split that into two articles, you get the same introduction paragraphs twice. But have a nice dinner, and enjoy the movie! --Dirk Beetstra ^{T C} 22:06, 22 October 2006 (UTC)

Dirk Beetstra, I think the article looks quite good now, I think the split into lab scale and industrial scale works Quantockgoblin 07:18, 23 October 2006 (UTC)

I was thinking about it later yesterdayevening, I think that when the sections about industrial distillation and the 'distillation in food processing' (the latter being really stubby) are big enough, they should be split from this article, so that the main article 'distillation' tells the general thing about distillation, tells theory, and tells the differences between batch and continuous. Then the article should point clearly to this three 'subfields' (I think this comes close to what [[user:mbeychok|mbeychok) suggests). But I am first going to do something more about the theory part, but I need a 'picture drawer' to help me a bit there. --Dirk Beetstra ^{T C} 07:29, 23 October 2006 (UTC)

Dirk Beetstra, do you need someone to draw pictures for you (e.g. me?, I can give it a go if they are not too complicated) or do you need a drawing package so that you can draw them yourself (I might be able to recommend some freeware)? What sort of images are you planning to draw? Quantockgoblin 10:02, 23 October 2006 (UTC)

I think the section on the theory would need some schematic pictures depicting the batch and continuous distillation, it would be nice if someone could give that a try (I'm not much of an digital artist). I am thinking in terms of schematic simple distillations (both batch and continuous, maybe depicting different stages of distillation). Maybe in the form of a distillation flask with e.g. blue and red dots in a certain ratio (for A and B resp.), and in the gas phase also some dots, clear other ratio, and same for the distillate. To clarify the difference, one could put a ratio of 1 : 4 in the crude mixture, and a ratio of 4 : 1 in the gas-phase in the start-situation. Feel free to connect it to the text, or rewrite the text to fit the drawing. I will have a look again to make the text more flowing and clearer later (if needed). --Dirk Beetstra ^{T C} 10:24, 23 October 2006 (UTC)

Dirk Beetstra I'm not too sure what you are after, something like this (n.b. the dot ratio can be changed if you want)? 20:19, 23 October 2006 (UTC)

simple distillation scheme

.

Hmm .. somewhere close, but than built into a 'life' distillation setup, with different shades in the different parts of the distillation .. if that can be made clear. I guess that could work, put a short fractionating column on top of this and build a setup just as in the top right of the page, put the yellow colour in the flask, with a certain ratio of dots as you did here, and another shade in the gas-phase above the boiling liquid, with another ratio, and that same ratio in the recieving bottle (that is, for the batch distillation). For the continuous distilation the picture is more difficult, how to make that clear? There it has to be clear that the total ratio of the removed fractions (the ratio of A and B when one would combine the two fractions) is the same as the inflow fraction, while the fraction in the flask is not the same as the inflow-fraction. --Dirk Beetstra ^{T C} 20:31, 23 October 2006 (UTC)

I have finished making a chemical engineering schematic of a Image:Continuous Fractional Distillation.PNG tower which I may be able to upload tonight into WikiCommons. I was planning to insert the pic into the Continuous distillation article soon. I made this pic in the same style as the 3 pics in Batch distillation. My pic shows a feed stream separated into 5 fractions; 4 distillate and 1 bottoms fractions. H Padleckas 23:32, 23 October 2006 (UTC)

Pic uploaded and added to Continuous distillation; see Talk:Continuous distillation. H Padleckas 19:05, 24 October 2006 (UTC)

Dirk Beetstra, as I promised here is a brief discussion of the different types of distillation used in the hydrocarbon processing industries that I am very familiar with ... i.e., oil refineries, petrochemical plants, natural gas processing plants (extracting natural gas liquids known as NGL's), and other hydrocarbon processing industries. Those industries probably have perhaps 80% or more of the industrial distillation columns in existence.

Other industries such as the pharmaceutical industry, the alcohol distilling industry and the fine chemicals industry also use quite a bit of distillation, but I am not familiar with those industries.

Major Industrial Distillation Types: The two primary types of industrial distillations are Continuous Fractionation or (Continuous Distillation) and Batch Distillation. The industrial Continuous Fractionation distillation towers are typified by the large, vertical, cylindrical columns as can be seen in the oil refinery photograph in the Fractional distillation article. Please note that by continuous, I mean 24 hours a day for 1 to 3 years before being temporarily shut down for maintenance ... and we are talking about towers with diameters ranging from about 65 centimeters to 6 meters and heights ranging from about 6 meters to 60 meters or more.

There are many subsets of the Continuous Fractionation primary distillation type, such as:

• Fractional distillation
• Vacuum distillation
• Azeotropic distillation
• Extractive distillation
• Steam distillation

The above subsets would be of approximately the same size range is the primary Continuous Fractionation towers. The vacuum towers require reinforcement (provided by a number of steel beams encircling the tower exteriors) so that they can withstand the difference in pressure between the exterior atmospheric pressure and the interior vacuum.

As for the vapor-liquid contacting trays or plates used in industrial distillation towers, it is virtually impossible to explain bubble-cap or valve trays (or sheet steel structural packing) without drawings or photographs. We need someone who could make such drawings. We also need someone who can make a drawing of a typical kettle-type reboiler commonly used as the heat input to a distillation tower (although there are other types of reboilers such as fired furnaces, horizontal or vertical heat exchangers, bayonet heat exchangers, etc.).

Finally, if you look at the the simple sketch that I made of a typical fractionation tower overhead system in the Fractional distillation article, that sketch needs to be made longer so that it shows the feedstream entry (at about the center height of the tower), and the bottoms exiting the tower and entering the kettle reboiler .... with the final liquid bottoms product leaving the kettle reboiler and the reboiled vapor returning from the kettle to the tower. - mbeychok 03:38, 24 October 2006 (UTC)

Hi Mbeychok. As I see it, I would not describe continuous and batch as 'industrial' terms, the same terminology is used for laboratory scale distillation (I see that batch distillation is almost fully explained from an industrial point of view), although continuous distillation is hardly ever performed on laboratory scale (I can only think of one example, and that is hardly ever done, it is involving a rotary evaporator), but that is semantics. I have tried to describe the general difference between these two in the article now, it could use a simple mathemathics example or some pictures to make it clear to, say, a highschool student (I guess that is a good target public for this article). I know that the timescale in industry is different, but the same principle applies, whether you perform a continuous distillation on a mixture which runs for a couple of hours/days (in general, until you run out of material to distill), or for several years (until you really have to clean your reboiler).

What I would suggest is, that you expand the paragraph 'industrial distillation', adding the list of subsets of continuous and batch distillations in industry, trying to give a short description (one to two paragraphs, probably defining differences with the lab-scale or general principle, and maybe saying what the major application is, without going into details), and point in each paragraph to a main article, which has a bigger description and some specific examples). I think that at the end, we may have to split out both the section 'laboratory scale distillation' and 'industrial distillation' into their own articles, leaving only an introduction paragraph on each of these pages, but the article is still handleable now, we will see if that will be necessary in the end. Once we have the basics right, the articles going more into detail should be easier to explain (I mean, explaining the differences between a batch distillation and continuous distillation in terms of a simple (almost theoretical) binary mixture is easy, and I think that has a good place in this article, explaining the complications that one has, either in a laboratory where you want to separate out your one, pure compound (formed in, say, 25% yield) out of a reaction mixture containing 10 components, or separating crude oil (of which I can't even imagine how many different chemical substances are in there) is another task.

As to the fractionating columns, what is there available on wikipedia, I guess it will end with vigreux, because that is generally the only fractionating column known to the common chemist. But packed columns, bubblecaps, etc. seem not to be very well known (and some of the 'industrial type columns' are also known for lab-scale work for difficult separations, I remember that I have once during my study have done an experiment using a column with many reboilers in it, I think it was a bubblecap-column (excuse me if I don't have the terminology right), where we had to withdraw samples from all the plates and analyse them by GC, and do some optimisation on it. By the way, I don't think that many chemist realise that the HETP and Van Deemter equation (as used in describing the working of a GC and HPLC, available in virtually every lab) relate back to the 'plates' in these columns!).

I foresee a lot of work, which I for sure cannot accomplish all by myself (also I have a major other wikipedia task at hand), but I could sure use some distraction from that every now and then. I hope to see you around, happy editing. --Dirk Beetstra ^{T C} 07:48, 24 October 2006 (UTC)

Continuous fractional distillation pic uploaded and added to Continuous distillation; see Talk:Continuous distillation. H Padleckas 19:05, 24 October 2006 (UTC)

Hi, may I suggest you also make a simpler pictures of the distillation setups in batch and continuous distillations? I have a degree in chemistry, with a broad background, so I can see what that picture means. But I feel that my sister (who is a bright person, but who does not have a degree in chemistry) would not understand that picture without studying it. Furthermore, I think that batch and continuous distillation are not per se industrial terms, as I tried to explain above (I work in a university lab, and I do batch distillations every now and then). I am afraid that these pages are going to be too difficult for a layman to understand. Could you please comment? --Dirk Beetstra ^{T C} 21:15, 24 October 2006 (UTC)

Dirk Beetstra, I disagree with you on this. I think that the drawing by Padleckas is excellent!! There is nothing wrong with your sister or anyone else not familair with the subject having to study the drawing a bit to understand it. I have a degree in chemical engineering and 50 years of industrial experience in laboratory work as well as large industrial plant design ... and there are many things in pure chemistry, physics, electronics, etc. that I would have to study in order to understand them since they are not subjects with which I am familiar. A chemistry lab drawing or an industrial distillation tower drawing simply can not be simplified to the point of being immediately understood by everyone. That's what comic strips are for. This discussion is an example of precisely why I advocated having two completely separate categories, namely Category:Laboratory distillation and Category:Industrial distillation. - mbeychok 21:45, 24 October 2006 (UTC)

Don't get me wrong, the picture is OK, very suitable .. but not in the introduction of continuous distillation, but we are writing an encyclopedia here, not an industrial manual for distillation. I do believe that the explanation of the subject should start at a lower level than what it is now. And I do believe that it can be drawn simpler than this. And I do totaly disagree with that we need comic strips for that. This is indeed an encyclopedia, not a comic strip. --Dirk Beetstra ^{T C} 21:54, 24 October 2006 (UTC)