8 replies to this topic

[Robert Montoya]

My friend is right, you have to compare the drop pressure taken of your BPSC, but is important that you evaluate the tower using the simulator manufacturer of trays, and heed in the flow of liquid for each stage in order to verify that the tower is handling the same flow of liquid that in the design conditions. This is a common problem in distillation towers when there is a variation in the feed composition or an increase in the input flow. The pressure drop indicates whether there is a problem in the tray eg fallen tray, valve trays in which they have been detached and require to be taken over by maintenance. Also evaluates the condensers and reboilers using programs such as this HEXTRAN or HTRI.

[Art Montemayor]

If you are a young graduate engineer and you are confronting challenges out in an operating plant with distillation towers, then I strongly recommend you buy, read, and study the following 3 books - all written by an experienced engineer who is reknown for his knowledge and training in the field:

TROUBLESHOOTING PROCESS OPERATIONS
4th.Ed.; By Norman P. Lieberman
ISBN: 978-1-59370-176-5

A WORKING GUIDE TO PROCESS EQUIPMENT
3rd.Ed.; By Norman Lieberman and Elizabeth Lieberman
ISBN: 978-0-07-149674-2

PROCESS EQUIPMENT MALFUNCTIONS
1st.Ed.; By Norman Lieberman
ISBN: 978-0-07-177020-0

You can easily locate and purchase these books through the Internet. You will never regret having made this type of investment in your career.

[sheiko]

Dear Art,

I have noticed you have quoted both "A Working Guide..." and "Process Equipment Malfunctions..." books.

If you have both, could you please tell us if the latter one is necessary to read after the former one (Working Guide)?
I mean, is there that much difference between both books?

I am asking because I was planning to buy the newest book (Equipment Malfunctions) now that I have read and studied the Working Guide...

Edited by sheiko, 23 August 2012 - 12:40 PM.

[Art Montemayor]

Sheiko:

Good question. Yes, I believe there is ample, different, and unique information to be found in the Liebermann book, "Process Equipment Malfunctions". It sells for $80 (new) and is priced in the same range as most of his books. This book contains the following material:

1. Distillation Tray Malfunctions
2. Packed Tower Problems
3. Distillation Tower Pressure and Composition Control
4. Salt and Rust Formation on Tray Decks
5. Fractionator Bottoms Product Stripping
6. Heat Extraction with Pumparounds
7. Reboiled and Steam Side Strippers
8. Inspecting Tower Internals--Checklist
9. Process Reboilers--Shell and Tube
10. Shell-and-Tube Heat Exchangers in Sensible Heat Transfer Service
11. Condenser Limitations
12. Air Coolers: Forced- and Induced-Draft Air Side Malfunctions
13. Cooling Water: Towers and Circulation
14. Steam Condensate Collection Systems
15. Steam Quality Problems
16. Level Control Problems
17. Excessive Ambient Heat Losses
18. Process Plant Corrosion
19. Vapor-Liquid Separation Vessels
20. Knock-Out Drums: Demisters and Impingement Plates
21. Hydrocarbon-Water Separation: Electric Desalters and Gravity Settling
22. Natural Draft Fired Heaters
23. Tube Failure in Fired Heaters
24. Fired Heaters: Air Preheaters
25. Disabling Safety Systems
26. Vacuum Systems and Steam Jets
27. Vacuum Surface Condensers and Precondensers
28. Excess Gas Overloads: Vacuum System Ejectors
29. Centrifugal Pump NPSH Limitations: Cavitation, Seal, and Bearing Failures
30. Centrifugal Pump and Driver Capacity Limits: Lubrication Failures
31. Steam Turbine Drivers
32. Centrifugal Compressors: Surge, Fouling, and Driver Limits
33. Reciprocating Compressors: Unloading and Efficiency
34. Summary: Typical Energy Savings and Efficiency Projects

And Norm doesn't waste time and words in getting down to the real important problems found with each of the topics covered. I think you will find this book very insightful and a learning experience - as is usual with all of Norm's writings.

I live in Houston, Texas and travel to Louisiana from time-to-time. I have bought books directly from Norm (& Elizabeth) who lives in Louisiana. Some of his books you have to buy from his publishers. In my opinion, Norm doesn't make much (if any) profit from his books and he has no reason to duplicate material and topics in his writings to increase revenue on the same subjects. He is kept much too busy traveling around the world giving his personal seminars on the same topics. Unfortunately, many bad engineers and students have made illegal, pirated electronic copies of his books and this has stolen his intellectual property. It is not only regrettable, but stupidity on the part of those pirates because what this does is that it deprives the rest of the engineering world from receiving new and more engineering books from such brilliant authors like Norm. The incentive to continue to spread engineering knowledge and experience is diminished because of the illegal pirated copies. We wind up being the losers -- as usual -- due to some stupid and bad people.

[Rajkumar Chate]

Hello My friend,

To evaluate the performance of trays and packing you can compare the operating pressure drop across the column against design pressure drop. Definately the performance of the column depends (both process as well as hydraulics performance) on the tower internals trays/packing. If you are interested to increase the capacity of the column then i will suggest to collect the present plant operating data, simulate the tower with any simulator, generate the vapor liquid traffic in the column and give it to any tray/packing vendor and ask them how much capacity we can increase with existing trays/packing or what will be the additional capacity if we replace the existign trays/packing.

If you want to improve the purity of any product then simulate it with considering 50-70% efficiency of the tray and make a plant data validation case, if you are not able to validate the plant data with considered efficiency then keep changing the tray efficiency and try to match the plant data in simulator. Once you finish this then you will come to know what efficiency your tray/packing is giving, if it is giving less efficiency as compared to required for separation then you can convert trays in to high efficiency packing to improve the efficiency and capacity. Keep in mind that all valve trays will have almost same efficiency and changing the valve type (except sieve and bubble cap) will not change the efficiency of tray un less and untill its design is wrong.


Rajkumar Chate

[sheiko]

Art,

I have started to read "Process Equipment Malfunctions" and you were right that it is a completely different book than "A Working Guide to Process Equipment". It is also more difficult to read so I would advise to learn how equipment works first by reading the latter book and then read how to solve the malfunctions...