Centrifugal Pumps and Amines
Centrifugal Pumps and Amines
(OP)
Can multistage centrifugal pumps be used to pump rich amines?
Are there any special considerations to be kept in mind when sizing pumps for these applications?
Are there any special considerations to be kept in mind when sizing pumps for these applications?





RE: Centrifugal Pumps and Amines
Mechanical seals in amine can be tricky. Many of our older amine pumps have been converted to dry gas seals. Since you specifically described a rich amine service, the risk of H2S release would dictate the use of a dual mechanical seal. We are not allowed to use API Plan 52 because this requires a vent to flare and our flare system is not suitable for amine in most parts of the plant. An API plan 53 is also a problem. Several of these pumps have suction pressures above 150 psi which makes the use of nitrogen pressure on the seal pot undesirable because nitrogen will go into solution in the barrier fluid and flash out of solution between the seal faces. A dry gas seal avoids these issues as long as you have a dependable source of nitrogen at a high enough pressure to supply the seal. The dry gas seals we have in use have performed quite well.
Our plant is in the northern US and freeze protection is critical. Steam tracing for freeze protection can resulted in hot spots that lead to accelerated corrosion. Electric tracing is very much preferred to protect against freezing without driving corrosion problems.
Johnny Pellin
RE: Centrifugal Pumps and Amines
Thanks for this info above. Its helpful.
RE: Centrifugal Pumps and Amines
Johnny Pellin
RE: Centrifugal Pumps and Amines
Most multi-stage manufacture use Monel K-500 shaft material as a standard. This is not a very good choice for amine service. Monel contains 27 to 33 percent copper.
One of the first identified incidents of stress corrosion cracking was termed "season cracking" in brass cartridge cases in jungle environments. Rotting vegetation gave off sufficient ammonia to crack brass cartridge cases but only in the rainy season – thus the term season cracking.
Several Amine applications have used Monel shaft material and got away with it, but corrosion cracking is a strong possibility with K-500.
D23
RE: Centrifugal Pumps and Amines
It is suitable in case high suction pressure, since the nitrogen in confined inside the elastomeric bladder of barrier fluid accumulator. Moreover the consumption of Nitrogen is limitated at the volume necessary to charge the bladder.