4 replies to this topic

[E-Tantoy]

Hello!

I am reviewing this project and came across a high pressure H2S absorber (17MPa) with its rich amine line going to a flash drum. I noticed that a PRT is installed in the rich amine line and according to one of the engineers, it is used to recover power exhausted from the high pressure line to the low pressure area.

Is this a common practice in the industry? What are the requirements to consider the installation of such PRT? Is it related to the nature of the fluid? Economic study? Because I checked the system, it was the only section (of the HDS unit) wherein the PRT was installed considering that there are many other HP to LP sections (wherein they could also implore such power recovery system).

Thanks much in advance. Ciao!

[riven]

Hello!

I am reviewing this project and came across a high pressure H2S absorber (17MPa) with its rich amine line going to a flash drum. I noticed that a PRT is installed in the rich amine line and according to one of the engineers, it is used to recover power exhausted from the high pressure line to the low pressure area.

Is this a common practice in the industry? What are the requirements to consider the installation of such PRT? Is it related to the nature of the fluid? Economic study? Because I checked the system, it was the only section (of the HDS unit) wherein the PRT was installed considering that there are many other HP to LP sections (wherein they could also implore such power recovery system).

Thanks much in advance. Ciao!

I do not know the specifics of your situation but I realise that the situation I describe below is slightly different. The recovery in this case is in the service side and not the process as ot appears for you.
However, power recovery is common in ethene crackers. The cracker runs at 800+C so approximately 80 bar steam can be generated. Using the motive stream, 4 turbine stages can be used to generated electricity and still leave 10 bar steam towards the end. This has been a large part in the improvement of the energy efficiecny of the production process.
See page 7
http://www.technip.c...ts/Ethylene.pdf
Turbines
http://www.mhicompre...turbine_02.html

The gain here is that the electricity generated can be used to drive or reduce the external power requirement of the propane refrigeration units as well as provide the steam to the ethylene purification train.

Edited by riven, 29 June 2011 - 06:00 AM.

[Zauberberg]

Installing hydraulic turbines has not been industry practice in the past - based on my experience, but I might be wrong. Usually there was no incentive to employ these devices in recovering fluid energy, as sources of power were readily available through some other proven ways, although these were more expensive. This is particularly applicable for Upstream Oil & Gas industry.

For several new installations and also in the last two projects I have been involved with, hydraulic turbines were considered during design stage and eventually installed in the plant(s). They used to recover around ~1 MW of power per machine by expanding refrigerant liquid from higher pressure into a lower pressure system. Perhaps this is not a substantial amount of power one wants to consider when evaluating concept of hydraulic turbine, but it seems that in the years that are about to come, more and more such devices will be installed worldwide. Apart from recovering power and energy conservation issues, hydraulic turbines also reduce enthalpy of the working fluid which can be quite important and beneficial e.g. in refrigerant loops or LNG production.

[Technical Bard]

Hello!

I am reviewing this project and came across a high pressure H2S absorber (17MPa) with its rich amine line going to a flash drum. I noticed that a PRT is installed in the rich amine line and according to one of the engineers, it is used to recover power exhausted from the high pressure line to the low pressure area.

Is this a common practice in the industry? What are the requirements to consider the installation of such PRT? Is it related to the nature of the fluid? Economic study? Because I checked the system, it was the only section (of the HDS unit) wherein the PRT was installed considering that there are many other HP to LP sections (wherein they could also implore such power recovery system).

Thanks much in advance. Ciao!

I have seen PRTs installed in both HP»LP Amine service and in the letdowns from HP separators in HDS units. However, in many cases when I have evaluated this, it wasn't economic because the cost of electricity for those sites was too low. Also, some operators have had poor reliability for PRTs and end up just using the bypass valve anyway.

[E-Tantoy]

Thank you very much for sharing your experiences: Riven, Tech Bard and Zauberberg.

I appreciate your replies.

It seems that it's a matter of economics.

I have handled LNG projects before but i didn't encounter such application in amine systems and so I wonder if it is a common practice.

Thanks again!