23 replies to this topic

[Anshul619]

Dear all,

 

I would like to know a good book where i can study and design a stripping column and still column in Gas Dehydration Unit(GDU).

 

Furthermore,If somebody can also provide me a book on designing the column internals.

 

I am new process engineer in a company.

 

Regards

anshul619

[Art Montemayor]

Anshul:

 

Why don't you simply use our free library where you can download an instruction manual that tells you how to do it - the original way it was done when the process was invented?  Today's simulators don't do it any better as far as the design results show.

 

http://www.cheresour...y-hall-of-fame/

[Anshul619]

First of all its an honour that your are the first person to reply on my first query.

 

I have been studying your and 3 more members comments on process calculation for equipement design especially GL Separator.

 

Thank you for the link and excel sheet provided there is wonderful.

 

But first i want to know the basics of the equipments,namely,

 

still column ; stripping column ; glycol contactor

 

 

It would be very helpful if you can direct me there.

 

Thank you

 

Regards

Anshul619

[Zauberberg]

Anshul,

 

Here are some attached materials. Some quality information you can find in classics such as GPSA Databook and "Gas Purification", by Koch & Nielsen.

 

Attached Files

•  Design Glycol Units for Maximum Efficiency.pdf   158.75KB   246 downloads
•  Improve Glycol Dehydration Unit Efficiency.pdf   2.76MB   237 downloads
•  TEG Dehydration Design Basis.pdf   49.6KB   293 downloads

[Art Montemayor]

Howdy Zauber.

 

It's always great to have you come by and visit a spell.  I hope you can stay around for a while.

 

Tell me, can you identify the author of the write up titled "TEG Dehydration Design Basis"?   The presentation is very subjective and I would like to put a name and a face on it if I can.

[Pilesar]

The article was on the internet at http://oilgasprocess...com/tegdehy.htm at least as far back as January 2007 without explicit author attribution.

[Zauberberg]

Hi Art, 

 

I think Pilesar is right - it is an internet article, downloaded from the abovementioned site. Personally, I like to read articles in which a particular piece or type of equipment is mentioned or recommended, based on someone's experience. It always gives more confidence, if it comes as a "first hand" story. It reminds me of Norm Lieberman.

 

However, you are right - perhaps I should have been more cautious before uploading it on ChE because I didn't have an opportunity to verify if 100% of the content is proven in operational practice, for all quoted information/equipment.

 

As for myself - back in Europe, after the job in Peru is completed. Maybe one of the most beautiful experiences in my life. Unforgettable place, unforgettable people.

 

Regards

Dejan

[Anshul619]

Zauberberg,

 

Thank you for these knowledgeable documents.

 

I have read these documents.

 

Sir as i am new process engineer, I would like to know about the sizing of these equipments.

 

Sir if you can direct me to a book or standard from which i can get the idea of how to size these above said equipments, I would be very thankful.

 

I have sized the separators and contactors sucessfully but I am facing problems sizing still column and stripper column in GDU.

 

I don't know any book from which I can study the sizing.

 

Again thank you for the documents

 

Regards,

anshul619

[Zauberberg]

Anshul,

 

Art has pointed you to the document from Sivalls he uploaded some time ago. Follow the link: http://www.cheresour...gn-manual-1976/ and visit page 10 and 17, where you can find information about sizing of the stripping still.

 

I'm sure somebody around you can land you a copy of GPSA Databook. In the Chapter 20, Dehydration, you can also find relevant information about glycol stripping and regeneration.

 

Regards

[Anshul619]

Zauberberg:

 

I am not able to see any formula for calculating diameter of respective column.

 

I have GPSA Handbook and Art's GDU Design Manual,but there are no steps given on how to calculate the dimensions of column and similarily there are no steps given in shell DEP.

 

Is the sizing of still column;stripper column and Glycol Contactor in GDU same??????

 

Regards

anshul619

 

 

PS:I have attached a document on stripper column but i am not able to understand how they are getting process stream variables(are they getting it from ASPEN HYSYS???).Maybe you can help me here.

Attached Files

•  Design of Stripping column .pdf   844.29KB   282 downloads

[Pilesar]

The Design of Stripping Column reference you just attached has a section on Flooding Velocity. The "A" parameter in the equation is proportional to the column diameter. You adjust the column diameter so that the column does not flood because of too high vapor velocity. 

[Zauberberg]

Your statement is incorrect. Sivalls' design manual, page 17, figure No.6, provides you with the information how to chose the diameter of the stripping column, given the TEG circulation rate and gal/lb of TEG per removed H2O.

 

If you are willing to perform it yourself, get a copy of packed column sizing procedure. It is available in quite a few engineering handbooks.

 

Edited by Zauberberg, 15 April 2013 - 07:06 AM.

[Anshul619]

Pilesar,

 

I think you are referring to HETP not Column diameter.

 

Because here, Diameter is proportional to Mass flowrate and inversely to Mass Flux of Gas.

 

Regards

anshul619

Edited by Art Montemayor, 18 April 2013 - 09:50 AM.

[Anshul619]

Yes sir you are right but what about column height.

 

will height be calculated according to contactor sizing guidelines???

 

and what about still column?????

 

 

And what about the document I attached with my previous reply????

Edited by Art Montemayor, 18 April 2013 - 09:50 AM.

[Zauberberg]

Anhul,

 

It helps a lot if questions are raised in orderly, organized manner. When we look at your original post, there wasn't many details you were asking for.

 

The still column is generously sized with 2 theoretical stages - 1 above the feed point, and 1 below the feed point. If you use packing, HETP varies from one product to another. Based on HETP of internals used, you will get your height. Shell DEP recommends 1 theoretical stage as sufficient for proper regeneration (minimum 0.6m packing below the feed, and 1.2m above the feed entry).

 

As for the stripping column, identical rules apply. One (1) theoretical stage in the stripper is more than adequate.

[Anshul619]

Zauberberg,

 

You are right about the sense of order of my questions.  I am very confused right now and don't know where to start and I apologize for any inconvenience.

 

I have understood your answer but how can I calculate and verify that what all calculations I have done are correct or not.

 

The diameter of column as you had told me through Art's GDU Design Manual is coming absolutely correct.

 

But how about height from HETP.???

 

I had attached a Design manual for stripper column; is this manual correct?  If so, how can I calculate:

1. Size of packing
2. Henry's Law Constant
3. Solute content in liq. inlet and outlet stream and gas outlet stream.

 

Please help.....

[Zauberberg]

Height from HETP is obtained directly. If you have selected 1 theoretical stage in your stripper column, and the HETP of 2" Pall Rings is between 0.40m and 0.75m, it means you need to have packing depth between 0.40m - 0.75m. You shouldn't be bothered that much about the column internals, the design comes from vendor.

[Anshul619]

Zauberberg,

 

We are using Nutter 1" rings in our stripper column.

 

And how can HETP be Vessel height or is it the factor by which we can calculate height???

 

If there is any text which emphasize on the relation between HETP and column height. Please direct me there.

[Zauberberg]

Anshul, we have already explained how HETP correlates with depth (height) of packing, and it is different for each type of internals. HETP value is normally provided by the vendor of column internals, for given service conditions.

 

Sulzer has some information on Nutter rings, see page 4 (graph and table) of attached document.

 

Attached Files

•  Random Packing SULZER.pdf   4MB   128 downloads

[Anshul619]

Zauberberg:

 

But sir, Is the height of packing and height of column same thing.

 

Because I know how long should be the packing according to Shell DEP 20.00.10.10.

 

Kindly enlighten me sir if the height of packing and the height of column same thing.

[Zauberberg]

Think logically - is a column filled with packing from bottom nozzle to top nozzle? Obviously no. There has to be allowance for liquid distributors, gas distributors, support grids, hold-down grids, surge volume in bottom, vapor diengaging space on top of packing, etc. etc.

 

GPSA chapters 7 and 19 provide some guidance on dimensions of these elements. Also, a few DEP's (gas-liquid separators, glycol dehydration) provide useful information as well.

[Anshul619]

Zauberberg,

 

Sir, I was getting confused when you were emphasizing on packed bed height rather than the total height of the column (WHICH I WAS ASKING).

 

Then I can use Glycol based Shell DEP??  If I can use, please tell me if I can size the column like contactor.

 

As I have sized contactor very easily, I might get the idea of sizing of column similarly.

[Zauberberg]

I'm glad we reached the conclusion. Have a good day.

 

Regards

[Anshul619]

Zauberberg,

 

I am glad I can now size column.

 

And thanks to you sir as you were instrumental in getting my solution.

 

And I believe I can ask you some question anytime.

 

Thanks