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NEW TECHNOLOGIES

Using centrifugal

pumps as hydraulic power

recovery turbines

The quest to maximize plant

energy efficiency, profitability
and sustainability

Luigi De Franco, Fluid Dynamics Design
Manager, R&D Department
Trillium Pumps Italy

he growing demand for energy effi- The R&D Department at Trillium Pumps Italy re-
ciency worldwide has led to the need cently conducted a study leading to the creation
for systems that can improve overall of design criteria to develop pumps as HPRTs
plant efficiency, including energy re- through the use of com-
covery in the thermodynamic cycle. putational fluid dynamics
T Hydraulic Power Recovery Turbines (CFD) tools for a finer esti- The R&D Department at Trillium
(HPRTs) are one such system. Unlike the standard mation of the turbine-mode Pumps Italy recently conducted
industry practice of dissipating pressure energy performance curve starting
into heat through a throttling valve, HPRTs can use from an existing centrifu-“a study leading to the creation
the residual energy at the pressurized flow outlet. gal pump with well-known of design criteria to develop
The most common areas of application for HPRTs characteristic curves in pumps as HPRTs through the
are related to water supply systems and proces- pump mode.
sing industries where a large amount of high-pres- The study included two use of computational fluid
sure flow is present at the end of the cycle. Using “API 610” centrifugal pum- dynamics (CFD) tools for a finer
an HPRT allows the residual pressure energy in the ps used as HPRTs, a rever- estimation of the turbine-mode
system to be transformed into useful power that se running multistage BB4-
can either feed the public grid utilizing an AC ge- type pump, and a reverse performance curve
nerator or reduce the power absorbed by another running single stage single
process train (i.e., centrifugal pumps) by connec- suction OH2-type pump.
ting the HPRT to the driver. The computational results were verified through
HPRTs can be either specialist fluid turbines or comparison with both theoretical and experi-
pumps with an inverse sense of rotation and flow mental data and ultimately confirmed:
direction. There are cost and environmental advan- • Theoretical methods to predict the HPRT
tages to utilizing pumps as opposed to turbines, performance in pump mode are affected by
and for energy recovery from fluid streams other a high uncertainty;
than water, “API 610” pumps are the most suitable • Numerical simulation is a valid tool to over-
solution. come the lack of accuracy of the empirical

Impiantistica Italiana - Gennaio-Febbraio 2024 53