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Naptha Pump

Naptha Pump

Naptha Pump

(OP)
Does anyone have any useful anecdotes, recommendations or similar for choosing a naptha pump?  We are in the process of evaluation of a gas turbine fueled on naptha, and it appears that the low lubricity properties of naptha leads to all kinds of medium and long term wear problems with pumping this fluid.  Some "solutions" include using a ceramic based bowl etc.  Does anyone have any specific recommendations regarding manufacturers or any hard luck stories (or good luck stories) they want to share?

RE: Naptha Pump

Which of the pumps for the gas turbine are you talking about? e.g. some GT manufacturers, that prefer multi chamber gas turbine designs... use 2 pumps in liq fuel applications... a centrifugal fuel forwarding pump (from the day tank) and a positive displacement main fuel pump.
Your concerns should involve both, as both are affected by the naphta low lubricity.
If anything, the fuel forwarding pumps are the lesser of your problems since they are usually redundant (2)...the main fuel oil pump is considered "critical" equipment as it is just one.
Perhaps I did not answer your question... but created more...well, just adding my 0.02$.
HTH
Saludos.
a.

RE: Naptha Pump

(OP)
Thanks for your post Abeltio.  You are correct in surmising the use of two systems.  The system proposed consists of a fuel forward system and a GT vendor supplied HP Pump skid with the single high pressure (40-50 bar) pump.

Do you know whether the only concern is wear of the wetted parts with these pumps?  Are there multiple designs, with one being better than the other?  Is there a specialty pump manufacturer that excels in these designs?

RE: Naptha Pump

Ken,
If you are the end user, your concern should be that it is perfectly clear to the OEM what kind and quality of fuel you are using. There is only a handful of GT manufacturer's in our planet... and this is not the first time a naphta pump has been used. They have a lot of experience and usually the design is adequate per the specified codes.
In any case you surely have a warranty covering the supplied equipment.

In the past I've used API design pumps for naphta service with no particular requirements, except the ones for hydrocarbons.

But!!! Using these pumps as fuel pumps is not the same... here are the most usual errors in liquid fuel systems that
may break your heart:

1. Poor system flushing before first fire.
System cleanliness cannot be overemphasized.

2. Ensure that the filtration system is properly commissioned

3. Ensure that the liquid fuel tank is settled at least for 24hs (72 hs optimum)

4. Ensure that liquid fuel suction from tank is from the top and not the bottom (floating suction).
Also, eliminate all water from liquid fuel tanks!!!!

5. Depending on fuel quality, are centrifugues required?

6. Check the whole system from the tank to the liquid fuel nozzles and check for high points, each high point must have a vent. You WILL have a high point whenever: the piping goes upward and then downward...e.g. picture an inverted "U" - exception is made for tubing 1" or smaller.
#6 is the single most common cause of liquid fuel systems instability or failure to ignite.
I've lost count of how many times I've been called to a site that presented problems when burning liquid fuel that was fixed by adding vents all over the place and making sure there was no air in the system.

HTH
Saludos
a.

RE: Naptha Pump

(OP)
Once again Abeltio, thanks for your advice.  Yes I am the end user and there has been a lot of discussion as to the long term robustness of these pumps.  Experience is often our best guide...

RE: Naptha Pump

Ken,

Value recycle has a used "naptha fuel" pump for sale...

Its just a Goulds centrifugal 3736 pump with a 30 hp TEFC motor..... Call em and ask about the seal...... Ask em who sold them the pump and find the seller.... ask the seller about his experiences.

www.valuerecycle.com/catalog/pumps.shtml

Also, as I recall, GE has published a "GER" tech guideline on the use of naptha as fuel for gas turbines....... poor lubricity is mentioned as a pump problem...... as, I recall there are insatllations in India of these units....

Good Luck......

Please keep us informed about what you discover

Also see:   http://mini-refineries.com/hi_tec.pdf

MJC

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