The Michoud plant demineralization
installation uses six Vanton vertical
sump pumps. Here, three acid pumps made
of Kynar PVDF are handling ambient H2SO4
at 20 gpm against a 55-ft. tdh. The
maintenance department replaced metal
pumps that experienced chronic downtime
due to corrosion.
Close-up of Vanton PVDF Sump Pump showing the epoxy painted metal motor mount and plastic protective coupling guard.
Thermoplastic Pumps Take
the Heat off Utility
Power, Energy and Utility
Caustics, Sodium hydroxide, Sulfuric acid
SUMP-GARD Thermoplastic Vertical Pump
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Reprinted from INDUSTRIAL MAINTENANCE & PLANT OPERATION
Caustics and acids no longer cause maintenance
Entergy Corp. is a large investor-owned utility headquartered in New
Orleans and serving customers in Arkansas, Mississippi, Louisiana, and
Texas. As part of a cost-reduction and profitability program,
management began a planned program of reducing maintenance costs
through equipment upgrades.
A big part of the upgrade program is an attempt to reduce corrosion
problems and boiler downtime associated with pumping acids and
caustics needed for water purification.
At the company's Michoud Power Plant in New Orleans, water bills
average $6,000 a month. Boiler water consumes 100,000 gal. a day, and
another 25,000 gal. per day are needed for cooling, sealing, and
regenerating and rinsing resins. A demineralization system is used to
remove dissolved solids that remain in treated water.
Entergy uses sophisticated ion exchangers in the demineralization
system because water flowing into the once-through boilers must be
extremely pure. Removal of dissolved solids from the water prevents
corrosion and scale problems.
The ion exchange purification process is complicated, but one of the
keys to the process involves regenerating a resin bed that strips mineral
ions from effluent water and replaces them with hydrogen. This is
accomplished by using concentrated chemical solutions, which remove
the depleted ions from the resin bed and replace them with hydrogen
and hydroxyl ions.
Pump performance is critical to this operation. Handling various
concentrations of sulfuric acid and sodium hydroxide create
contamination and corrosion problems, which resulted in high pump
maintenance costs and excessive downtime. As part of the corporate
cost-saving initiative, the maintenance reviewed alternate chemical
The review prompted John Erwin, maintenance superintendent, to test a
vertical centrifugal thermoplastic pump on the caustic system. Erwin
chose the Sump-Gard® pump from Vanton Pump and Equipment.
The pump was required to deliver 20 gpm of 50% caustic at 108°F
against a 46-ft. total dynamic head. To handle this task. the Sump-Gard's
casing, flanges. impeller, vertical column and coverplate are made of
homogenous virgin polypropylene. Even the pump's 96-in. vertical shaft
is isolated from the solution by a thick polypropylene sleeve, and a
special shaft seal protects the bearing and motor from corrosive fumes.
Results of the test were excellent, and a similar pump was installed on
the acid tank. To handle the H2SO4 however, the material specified for
the wetted end and the shaft seal was Kynar® PVDF. This pump was
required to deliver 20 gpm of acid at ambient temperatures against a
55-ft. total dynamic head.
Because of the performance and service records of the two initial
pumps, John Erwin decided to replace all six metal pumps with
thermoplastic pumps manufactured to the same design specs as the
test units. In this case, Entergy's upgrade program paid off handsomely.
Each of these three Vanton Polypropylene
pumps delivers 20 GPM of 50% caustic at
108°F against a 46-ft. total dynamic
The sulfuric acid and sodium hydroxide
required for the ion exchange
purification process is stored in these
large tanks outside the processing
building. Note the concrete containment
vault to catch any spillage.
In the 1950, Vanton developed a revolutionary all-plastic pump for use in conjunction with the first heart-lung device. The design limited fluid contact to only two non-metallic parts: a plastic body block and a flexible liner. This was the birth of our Flex-I-Liner rotary pump. Its self-priming sealless design made it an industry standard for the handling of corrosive, abrasive and viscous fluids as well as those that must be transferred without contaminating the product. Vanton now offers the most comprehensive line of thermoplastic pumps in the industry.
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Vanton Pumps (Europe) Ltd.
Unit 4, Royle Park
Congleton CW12 1JJ