Effect of tie-in point downstream of Pump

[Ross1985]

Hi all,

My first post on these forums.

Hopefully this will be an easy one to answer:

I've been asked to review how/if tie-ing a water main to a Methanol flowline will effect the Methanol pumps upstream of the tie-in point. I'm trying to figure out if an increase in density or if a change in compressibility (which I think should be very low) will have any adverse effect on the pumps. The water tie-in will be fully rated and at a pressure similar to the Methanol. Both liquids are pumped using PD pumps as well.

I can't see there being any adverse effect, but thought it might be a good idea to get a few more opinions.

Any input would be much appreciated.

Ross

 

[LittleInch]

Unless your line is very flat, very short or you are adjusting the methanol flow so you are flowing at a total of less flow than before then the answer is yes, there will be an impact on the upstream pumps due to higher pressure.

The pressure seen by the pump will increase due to increased density so any elevation changes will cause the pressure seen to increase, more flow equals a higher head / pressure required to move more fluid through the same size pipe and water has a higher viscosity than methanol hence higher unit losses per flow per unit distance.

Higher pressure for the same flowrate in a PD pump means more power consumed.

Calculate the pressure required to pump your methanol then separately calculate it for your new (higher) flowrate of this water / methanol mix.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[LittleInch]

Did it answer your question? It's good to get feedback / response from posters

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way