Chemical Engineering March 2011 - 27

Blackmer
Newsfront
JUST YOUR TYPE
ince the 1970s, a major U.S. Gulf Coast area refinery
had used reciprocating positive-displacement (PD)
pumps for wash water service. The PD pumps were
costly to operate, posed environmental complications and
required frequent maintenance. Wood Group Surface
Pumps (Houston) designed and engineered an economical
Surface Pumping System to replace the PD pumps
at the refinery. The new units feature easily replaceable
multi-stage horizontal centrifugal pump elements and are
designed for improved abrasion resistance, reduced wear and
higher efficiency. After the units were installed, the refinery
eliminated leakage and environmental issues and achieved 100%
uptime with 24/7 reliability with no failures. Quarterly changes of
the thrust chamber lubricant and routine vibration measurements
are the only maintenance needed thus far.
Obviously, selecting the right pump for the application can make
a big difference in reliability and efficiency. While in this case,
centrifugal pumps were swapped in for an alternative type, this
is not always the solution. Centrifugal pumps are the most widely
used type in the chemical processing industry, but they may not
always be the best choice for a given application.
" A lot of process engineers automatically select a centrifugal
pump because it is what they know, " says William Bohr, director
Mouvex
S
of business development with Blackmer
(Grand Rapids, Mich.). " But that
doesn't make it the right pump
for their application. Broadening
your knowledge of different
pump types can go a long
way toward finding the most efficient
pump for a process. "
Xavier Rasotto, market manFIGURE
3.
The Blackmer ML Series
pump offers self priming
and run dry capabilities to
extend its operational life
ager, chemical, with Mouvex (Auxerre,
France), agrees. " Awareness
of other pump types is one of the
biggest challenges for chemical
engineers. Some chemical
engineers
may not be familiar with the
technology and benefits associated
with other types of pumps, " he says.
" Since pumps are responsible for
the second highest number of industrial equipment used after electrical
motors, selecting the right kind of pump for any fluid transfer
applications is a critical task. "
And, once the choice for an alternative pumping technology
has been made, users will often find there are advances within
each of these pump types that can further boost energy efficiency.
For example, Greg Duncan, director of engineering and technical
support with Wilden Pump & Engineering (Grand Terrace,
Calif.), says the company's ProFlow X air distribution system was
designed to reduce energy consumption in its air-operated double
diaphragm pumps. " It has an efficiency management system that
allows the customer to select the optimization point he needs to
find the perfect balance between efficiency and performance for
a specific application. "
FIGURE 2. The S LP
Series is a rotary positive
displacement pump that
is not based on a magnetic drive.
This seal-less sliding vane pump features no magnets, no
mechanical seals and no packing, making it easier to maintain
of flowrate, process upset conditions
and overall pump performance, " says
Prayne. " It is typical to achieve a 30%,
to as high as 70%, reduction in energy
with our solutions. "
Jeff Theisen, commercial project
engineer, standard drives and motion
control with Rockwell Automation
(Milwaukee, Wis.), agrees that
monitoring and control can go a long
way toward reducing energy costs.
" Power monitoring and control devices,
such as energy-efficient motors,
sophisticated controllers and software
and variable speed drives - all
of which can be networked together,
provide more accurate information
about actual production costs, allowing
managers to make more intelRealizing
that the most energy-efficient solution to the pumpshaft
sealing challenge is a seal-less drive, Mouvex has developed
the SLP Series of sliding vane pumps. The SLP Series is a
rotary positive displacement pump that is not based on magnetic
drives, but, rather, a seal-less, leak-free design that features no
magnets, no mechanical seals and no packing. When compared
to magnetic driven pumps, the SLP creates up to a 40% reduction
in absorbed power and up to a 20% higher return in energy efficiency,
says Rasotto.
ligent business decisions, " he says.
However, he adds that to enable
such knowledge, an effective monitoring
program is essential. Such a
program should include a network of
digital power-monitoring devices that
capture and communicate power-consumption
information. These devices
are used to measure electrical parameters
associated with a specific bus in
a facility's electrical distribution system.
This allows plant managers to
gather detailed information on power
consumption in different parts of their
plants, on specific machines and even
on individual product lines.
By metering consumption, small
opportunities for improvement can
be identified to provide a significant
26 CHEMICAL ENGINEERING WWW.CHE.COM MARCH 2011
impact on energy usage, resulting in
immediate financial gains. And, in addition
to usage data, managers have
access to power-quality information
that can improve productivity and
lengthen equipment life, further enhancing
profits and efficiency.
Improving reliability
" The initial purchase price of a pump
represents only about 10 to 15% of the
total lifecycle cost of the pump, with
energy usage being the largest cost, "
says Rich Whidden, applications engineer
with Griswold Pump Co. (Grand
Terrace, Calif.). " Maintenance, repair,
labor and associated downtime costs
make up the remainder. "
For this reason, Whidden says, one
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