50% Formaldehyde Solution Pump Selection 3

[Watkins1j]

Process Conditions:

We currently have 2 pumps in this service, one which charges our reactors and one which is recycling back into the storage tank. The recycle pump is a low pressure pump - discharges at 33 psig and is run though a heat exchanger to keep the process fluid around 90 F to 150 F. The High pressure charge pump discharges at 204.7 psig and is pumped out at ~145 F. Both pumps are Gould's 3196's with John Crane double mechanical seals.

Current Issues:

The current seal piping plan is 53 with Royal Purple 22 barrier fluid pressurized with nitrogen no flush plan included. The issue we have using oil as a barrier fluid is once the seal fails we loose oil into the process which than gets into the catalyst in the reactor causing high boils....not good for our process. This currently happens every 4-6 months.

My question:
I am looking to upgrade these pumps from the Gould's 3196 to either a can motor pump (Nikkiso) or a Mag drive pump (HMD Kontro). I am also looking at keeping the Gould's pumps and changing from a wet seal to a dry gas seal using nitrogen as the barrier. Does anyone know the benefits to switching to a sealless design or know of any issues using either the mag drive or can motor pump in Formaldehyde service. Or is there a better solution to eliminating oil as a barrier fluid?

The main thing I am asking is what type of pump does anyone else use in similar services that has worked for them?

 

[Pumpsonly]

If the liquid is clean , is better switch to Mag drive or Canned motor pump.

 

[Watkins1j]

Thank you Pumpsonly, I am looking for pros and cons of both to see if it is benificial to switch. In our current situation the service is dirty with < 1% solids. I have a canned motor pump specified but it requires a cooling water line to circulate in the motor section of the pump. So we could still have the possibility of water leaking to the process. Does anyone have experience with a canned motor pump using cleen cooling water as a flush to circulate within the motor section of the pump? Have you had issues with water leaking to the process side of the pump?

 

[Pumpsonly]

The cooling water for the canned motor pump is for cooling the motor and will not get into the process. The cooling water runs through an external jacket surrounding the motor body. Inside the motor body there is another shell separating the motor
stator from process liquid.
Less than 1% solids can be handle by Mag drive pump and no cooling is required.
Check out

http://www.klausunion.com/

 

[JohnGP]

When I had the pleasure of working in a formaldehyde plant many years ago, we used a mag drive pump to transfer 50% formaldehyde from column to storage. We didn't have any issues except for the need to check and regularly replace the (as I recall) carbon bushes that the pump shaft ran in. It was a new plant and mag drive seemed to be the standard selection at the time for that duty.

 

[pumpking]

We do quite a lot of business with our mag drives on formaldehyde duties, the solids content is better on mag drive than canned motors as lubrication routes are quite critical, while i say better on mag drives, there are still of course limits to be aware of and various protection devices to make sure pumps are fully protected.

If you wish to discuss more, please do get in touch. Good luck !

Ash Fenn

http://www.cdrpumps.co.uk

 

[DubMac]

Goulds also makes a Mag-Drive, I think it is the 3296, not sure of how it stacks up to a Kontro though. It might be possible to drop in on the same baseplate as your 3196???