A pumping trap is more energy efficient because essentually all the steam energy used for pumping is recovered back into the condensate as heat. These traps seem like the work fine for years having only nominally more problems than float traps (somewhat more moving parts). For high pumping rates a feed reservoir or duplex type unit may be required.
Using centrifugal pumps draws electricity and therefore has more operating costs. We have a number of pumps returning condnsate from big users and that type system is not maintenance free either. The initial cost (including spares, wires, starters, MCC capacity, etc) and maintenance costs (as a function of capital cost) are likely to be significantly higher for a centrifugal pump.
Basically I would make my decision based on the economics and the amount of condensate being returned. Equipment sizing sets some litits such as pumping back too small of a return (<5 gpm) with a centrifugal pump is impractical, as is pumping back too large of a return with a single pump trap (>50gpm). In the middle range you can go either way.
Of course the best option of all is to avoid either option by raising the process side temperature (tower pressure) to avoid any stall problems and just use a float trap. That's my experience anyway, others may have a different view.
best wishes,
sshep
