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Teg/amine Units Pump

pump;npsh;teg;hysys

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#1 Steve90

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Posted 17 April 2015 - 11:36 AM

hi !

Anyone can tell me why in almost all hysys simulations of TEG and  Amine units we place the lean TEG/AMine pump before the cooler and not cooler then pump before recycling ?

 

Is there any problem of cavitation at low temperature ?

 

 



#2 Zauberberg

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Posted 17 April 2015 - 11:56 AM

There are several reasons:

 

1) Avoid high-temperature, expensive materials for pumps

2) NPSH

3) Controls (e.g. partial cooler bypass - they introduce additional pressure drop and may starve the pump)

 

There are designs which introduce two-stage pumping, i.e. a booster pump followed by the circulation (high pressure) pump. Some designers install lean/rich exchanger upstream of the booster pumps, if layout and NPSH allow for such design. The final trim cooler is always on the discharge of the high pressure pumps.



#3 Steve90

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Posted 17 April 2015 - 12:11 PM

Thanks Mr Dejan but i didn't get how can we avoid high temperature in pump when placing the cooler after the lean TEG/Amine to recycle pump?



#4 Zauberberg

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Posted 17 April 2015 - 12:26 PM

See the last paragraph of my previous post - by employing lean/rich exchanger between the booster and the circulation pumps.

I have rarely seen a single pump that takes glycol or amine from the regenerator and pumping it back to the absorber.



#5 MTumack

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Posted 17 April 2015 - 04:30 PM

Its a manufacturing issue. When you are talking about high temperature pumps, you are talking about a device made from several different materials that has to rotate within a housing in incredibly tight tolerances. You are also talking about precision ground, Quench & tempered components.

 

A high temp pump is unrealistic because of these things. With 3 separate thermal expansion coefficients, and the requirement for tight tolerances, it makes manufacturing high temperature pumps unrealistic; you can't design a pump for 600°F then assemble it at normal conditions otherwise you have things going wonky when it heats up; parts that warped during expansion, errors in . You also cannot assemble and manufacture a pump that is 600°F hot because no one would actually do it at a reasonable price.

 

Then you factor in that the heat messes with Steel's ductility, and conversely its hardness and Wear resistant properties. Add in the slow annealing caused by the high heats slowly expanding a steels molecular structure and destroying its desirable heat treated traits.

 

You never see pumps taking full heat fluids because it is significantly cheaper to have a booster pump, cooler, pump, and additional heater than it is to have a pump manufactured robustly that is designed to handle the heat. Its kind of like trying to get a cow to run to its no owners home... theoretically possible, but it is much easier to just put it on a truck, if that makes sense.



#6 Steve90

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Posted 18 April 2015 - 03:17 AM

Thanks



#7 Steve90

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Posted 21 April 2015 - 10:43 AM

Dear,

 

I would like to know why do we use two stage pumps ( Booster & circulation !!!) is there an issue related to the available NPSH or is it for manufacturing range for pumps .

 

As far as I know , if the vapor  of the process fluid is low enough ( 30% by weight DEA ) , we are far from the risk of cavitation. I m deadly sure we need to pump the regenearted aqueous DEA 30% by weight before cooling since the convection coefficient h increase at high velocity and flows as well !!

 

Your prompt reply is highly appreciated.



#8 Zauberberg

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Posted 21 April 2015 - 11:07 AM

For a real, industrial plant, you will probably end up with a multi-stage centrifugal pump in amine circulation service. For glycol plants, due to much lower capacities, designers normally opt for positive displacement pumps.

 

Multi-stage centrifugal pumps require significant NPSH which cannot be achieved by simply cooling the amine solution to whatever temperature. We are speaking here of a few meters of available Head at the best (you don't want to elevate the regenerator tower 20 meters above ground level in order to provide additional suction head). Thus providing booster pumps remains the most effective solution.

 

Multi-stage pumps are less forgiving with regards to lack of NPSH than single-stage pumps. Hence nobody wants to play around with +/- several meters of Head and risk a serious damage to the circulation pumps. They are very, very expensive items.

 

On the other hand, I have seen a few TEG plants where only high-pressure circulation pumps were used, without booster pumps. The problem associated with this concept (apart from risking pump damage due to insufficient head) is that you need to design all the equipment on discharge of this pump for a pressure at least equal to the design pressure of the positive displacement pump. This all usually brings more cost than having a pair of booster pumps.



#9 Steve90

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Posted 21 April 2015 - 11:18 AM

Thanks Mr Dejan, for the TEG circulation pumps I think that they are using Kimray , there is no risk of cavitation , they are not centrifugal !!

 

Is that right ?



#10 Zauberberg

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Posted 21 April 2015 - 11:24 AM

Every pump can cavitate, regardless if it is centrifugal or reciprocating. Cavitation is caused by vaporization or flashing of fluid inside the pump, and hence all pumps can be subject of cavitation.

 

Kimray pumps are specific in the sense that they use energy of high-pressure wet glycol to circulate glycol solution. Due to friction losses, elevation changes, etc., a supplementary source of energy needs to be used for that purpose. So that is either absorber gas or electrical power, used in so-called hybrid pumps.

 

Read more at: http://kimray.com/Po...ents/PB0004.pdf



#11 beautiful mind

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Posted 28 May 2015 - 05:46 AM

Mr Dejan 

 

I am working on a glycol dehydration unit , the unit is built to treat 27 MMSCFD of sturated gas @ 1200 PSI , now due to the turndown rate 15 MMSCFD @ 450 psig is being treated , so I am performin the calculation and i did the adecquacy check of all the equipments ,  I am suspecting that the Kimary pump is not circulating the required flow rate as the Head decreases from 1200 psi to 450 psig .

 

To be concise , my question is : the kimary  pump flowrate decreases proportionnaly to the decrease of the head and the exchanged energy or not ?? I am deadly sure that the flowrate circulated with a kimary pump is proportionnal to the stroke per minutes of the pump !!

 

 

Regards 



#12 Art Montemayor

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Posted 30 May 2015 - 12:49 PM

Mustapha:

 

Firstly, this is the Simulation Forum and this new topic you have introduced IS NOT A SIMULATION TOPIC.  You should start a new thread (perhaps in the Industrial Forum) that is dedicated to your query on Kimray TEG pumps.  Additionally I am assuming the usernames Steve90 and Beautiful Mind are the same user from Tunisia.  Our members will get very confused and over-worked if posters use multiple usernames on the same topic - this is needless work and repetition.  It only contributes to frustrating and taxing our professional members who already are dedicating their valuable time and effort for free.  Please explain.

 

As to an answer to your query on Kimray pumps, please read the brochure that Zauberberg has so kindly furnished.  I am submitting another Kimray version of the same subject so you can also read through that.  You have obviously not read Zauberberg’s contribution or else you would have become aware that the answer to your query is found plainly in its content.  Look at the performance tables and curves for the different Kimray pump models and you will note that there is a definite capacity drop (approximately by a factor of 4 or 5).  I believe Zauber’s brochure is more recent than mine.  This plainly answers your specific query.  And, of course, the delivery of any positive displacement piston pump is going to be dependent and nominally proportional to its rpm (the number of strokes per minute) and its stroke.  That is fairly obvious and logical.

 

If you, in fact, are the owner of a Kimray TEG pump model you have the privilege of contacting Kimray directly and the folks there will tell you EVERYTHING you want to know or need in regards to that pump model.  They will also discuss with you the capabilities of their other model pumps and how they can be upgraded.  I know because I have done this before.  You could never find another more cooperative and helpful manufacturer than the family-owned company of Kimray, Inc.  Read the attached document regarding this company, its history, and especially about the man who invented this ingenious and novel pumping device - Garman O. Kimmell.  I wish all our members would take the time to read this story about Garman and especially about his life as a practicing engineer and human being.  It has to make you proud that there have been such persons in our engineering profession and that their work is being carried on.

 

I once worked for Black, Sivalls, and Bryson and had the honor of meeting Garman later on in my career.  He was a remarkable, talented, and caring engineer who inspired others around him.  His products speak for themselves.

 

I hope this addresses and answers your query and offers all our members some very interesting historical engineering information about a very noble American engineer.

Attached File  Kimray Glycol Pump.pdf   5.31MB   47 downloads

Attached File  Garman Kimmell - Founder of Kimray.docx   59.68KB   28 downloads



#13 Steve90

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Posted 30 May 2015 - 01:28 PM

thank you Mr Art for your valuable informations ! concerning the usernames, me and beautiful minds are 2 different persons but close friends and both of us are young process engineers and we worked also on TEG unit ! we are really sorry for this misunderstanding !

#14 beautiful mind

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Posted 02 June 2015 - 11:22 AM

Thanks Mr Art for the attached documents , As my friend said we are two engineers working on the same project !! 






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