Hot Glycol 1

[curtis26]

For a triplex pump moving hot glycol at 250 deg. F, what options/accessories/recommendation need to be considered/included?

How would this differ from a pump moving salt water with the same operating condition at ambient temperatures.

 

[micalbrch]

First of all hot glycol at 250 °F and salt water at ambient temperature are completely different media. You have to consider the temperature limits of seals and gasket. For ambient temperature you can use nearly any plastic, for 250 °F FPM and PTFE must be used. The plunger packing design is a very important issue at this temperature, too. You might need a flushed packing design for hot glycol. The suction side conditions must be considered as the two fluid have different vapor pressures (cavitation must be avoided). And so on and so on. What is the background of your question?

 

[curtis26]

I am mostly interested in material recommendations for glycol (fluid end, seals, plunger packing style, plungers, valve recommendation, etc.) and what measures for heat dissipation are recommended for hot liquids.

For new pumps I what to know what pitfalls are common for hot glycol and what is necessary to protect the pump and lengthen the life of the expendables.

The triplex pumps that I am most familiar with are oilfield designs with the primary application of salt water injection. The water injection configuration is "standard", so we usually have to start there and request modification by specifying the alternative materials and optional accessories.

I made this question vague on purpose because the first thing that comes to mind when one sees 250 Deg F. Glycol will likely be different for everyone and I don't want to limit anyone’s comments by making this to specific. I am sure there is more than one solution to this application so I welcome everyone’s comments. Especially those of you how have field experience (good or bad) with this hot glycol pumps.

 

[micalbrch]

O.k. Cast iron and steel are good for glycol, even at hot temperatures. Use FPM for static seals like O-rings. For the plunger packing PTFE is the best choice and pretty common in any case for packings. Common plunger materials are surface hardened stainless steel and ceramic coated stainless steel. Ceramic coatings do not like rapid temperature changes but I suppose you will not start the pump at -20 °F with 250 °F glycol. Make sure you get a slow running plunger pumps (< 300 rpm) to avoid that friction of the plungers in the packings will create additional heat. As mentioned before a flushing ring for the plunger packing can be a good choice and if water isn't an option you can use cool glycol. What else? You need a pressure gauge with diaphragm type transmitter and you have to make sure that the pump does not cavitate (vapor pressure of 250 °F glycol must be obeyed).

 

[btrueblood]

I'm a bit hesistant to agree with using FPM for static seals. EPDM will work just fine for static seals with hot glycol. Some (perhaps even "a lot of") fluoropolymer elastomers will actually degrade faster than EPDM in hot glycol; there are some types that do better than others, but finding them can be tricky. Everything else mical has written sounds good.