Offloading 29% aqueous ammonia with sliding vane pump

[Yuze]

I am designing an aqueous ammonia offloading station to unloading 29% aqueous ammonia. I recommended using a positive displacement pump (sliding vane from Blackmer). But this pump is not designed to meet API 676 spec. The pump capacity will be 180 GPM and discharge pressure is 20 psig. Any one has experience with this kind pumps for such service?

Thanks,

Yuze

 

[MJCronin]

Yinz...

Please explain why you must meet API-676 for aqueous ammonia loading service ...

API-676 was written in order to help specify robust rotary pumps for viscous oil-industry service.

I do not believe that you need such a pump.....

Your rotary vane pump is the correct one.

Tell us more about your insatllation..

-MJC

 

[Yuze]

Thanks MJCronin!

The reason that the pump must meet API 676 is our company specification requirement, basically for quality control.

Twe years ago, the company started the ammonia unloading facility project. As I said, the aqueous ammonia is 29% aqueous ammonia. In the summer time, the ambient temperature is about 30°C (86°F). Normally, the tanker truck will travel about 700 KM to the site. At the worst scenario, the truck may have to wait two hours to be unloaded. This means that the ammonia inside the tanker is almost near the boiling point. To meet the NPSHR for the pump, we designed a canned pump (centrifugal) 15 ft underground with complicated control system to avoid cavitation problem. Over budget caused the project being cancelled.
This time I tried to avoid the underground pump. The pump distributor recommended using rotorary sliding vane pump. I think this is the correct option. I recommended using the PD pump. However, the pump supplier specifically states that the pump does not meet API-676. I am trying to create a spec deviation for the installation of this kind pump. The pump supplier sent an 18 pages document to show the discrepencies of the pump design to API 676.
We don't have experience with this kind pump installation. Hoping that someone with experience with this kind pumps provides your opinions, we will make the final desicion.

Thanks,

Yuze

 

[BenThayer]

the blackmer pumps used to be (still are?) relatively common on anhydrous ammonia trailers for about the same reason.

does the shipper offer a trailer with its own pump as an option? if so, you do not need your pump.

also, are you venting your storage tank back to the trailer when off-loading? if so, you might consider the compressor method.

you might look at some of the links here for more info:

http://www.rmtech.net/technical_information.htm#NH4OH MSDS

i used to be involved making it but never unloading it.....

 

[pumpking]

An option is a mag-drive pump, we have vast experience of tanker unloading applications, typical target time for unloading 24000 litres is 45 mins (not sure what capacity trucks you are using).

We unload with standard end suction pumps - lots of considertations for installation, layout and more importnatly control, however, we have lots of pumps successfully doing this duty. Alternatively, we can look at self priming mag dirve pumps for such a duty. Have a look at the web-site to see some news features on tanker unloading, and im sure you will be able to pick up some important considerations - excuse me if this sounds like a sell...

Ash Fenn

http://www.cdrpumps.co.uk

 

[micalbrch]

Mag-drive pumps and gear pumps are common on ammonia services. Vane pumps might work as well but I haven't heard of any (which does not have to mean anything).

 

[Yuze]

Thanks Pumpking & Micalbrch!
Could you recommend some of the pumps used on ammonia survices?

Yuze

 

[micalbrch]

Try

http://www.vikingpump.com

or

http://www.axflow.com.

They both make ammonia pumps and I have no relation with any of them.

 

[pumpking]

I am of course biased, but we manufacture such pumps -

http://www.cdrpumps.co.uk

Ash Fenn

http://www.cdrpumps.co.uk