Pumper drums VS NH3 pumps. Energy saving

Hi Guys
On a different note
Does any other country know a pumper drum that is used to pump liquid ammonia in the place of a normal hermetic or Witt pump?
We make use of double pumper drums that uses flash gas to rise the pressure in a vessel to pump liquid ammonia. GEA apparently made tests and compared to Witt pump energy usage and according to them it uses more energy, this does not make sense as flash gas is a wasted energy when filling the accumulator.

My opinion is that they spread this story as they are losing money not selling pumps.
We have pumper drums running for more than 30 years with no maintenance needed, but overhauling a Witt pump is expensive these days.

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Originally Posted by Lodiev

Hi Guys
On a different note
Does any other country know a pumper drum that is used to pump liquid ammonia in the place of a normal hermetic or Witt pump?
We make use of double pumper drums that uses flash gas to rise the pressure in a vessel to pump liquid ammonia. GEA apparently made tests and compared to Witt pump energy usage and according to them it uses more energy, this does not make sense as flash gas is a wasted energy when filling the accumulator.

My opinion is that they spread this story as they are losing money not selling pumps.
We have pumper drums running for more than 30 years with no maintenance needed, but overhauling a Witt pump is expensive these days.

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Lodiev,
With pump-a-drum system it probably is a little less efficient if you use hot gas to transfer it.
Find it hard to believe you have had no maintenance on it in 30 years though, as lots of valves
that have to work correctly.
Pumps are simple & if no cavitation could last for 10 years between services.
As with liquid injection, all these things have a place.
You would not convert your transfer system to save only a few dollars.
Also who cares what GEA think, not me.

Typically, ammonia pumps use 1-2% of plant energy. Better type of pumping will save fraction of 1%. Why to bother? Lowering condensing pressure by 1 psig will save you more than right pumping.

I know I am responding to an old thread, but I have been off line for awhile. GEA is telling the truth, Wilbert Stoecker in his book "Industrial Refrigeration Handbook" shows that gas pumping uses between 50% to 100% more energy than a mechanically pumped system. A gas pumped system is using the compressors to push the liquid. That being said changing an existing system requires a very careful analysis and proper pump selection.

GEA wasted money on there testing, they should have read Wilbert Stoecker, or maybe they did & went to the Pub!