Chemical Engineering August 2013 - 12

(Continued from p. 10)
CHEMENTATOR
Reduce air consumption from AODD pumps
with this technology
ew technology developed for air-operated,
double-diaphragm (AODD) pumps
can reduce consumption of compressed air
by up to 60% without electronic components,
while maintaining the same flowrates. The
reduced air consumption translates directly
to lower energy usage.
Developed by Wilden Pump Inc. (Grand
N
Terrace, Calif.; www.wilden.com), and tradenamed
the Pro-Flo Shift Air Distribution
System, the technology consists of a cylindrical-shaped
air-control spool that shifts
back-and-forth between the two diaphragms
of the AODD pump. The spool automatically
meters air toward the end of the pump
stroke, optimizing the pump's performance,
explains Wilden innovation specialist and
technology inventor Carl Glauber.
The mechanically actuated spool works by
controlling the timing of the air intake during
the pump cycle, restricting the airflow
from the compressor toward the end of each
pump stroke. The pump cavity is thereby
filled with only enough air to maintain the
fluid flowrate, but no excess air. Although
improvements have been made to the airdistribution
system of traditional AODD
pumps, a significant amount of air is still
being lost during the time period from the
end of the pump stroke to when the air valve
shift is completed, explains Glauber. By restricting
the air supply to the air chamber
toward the end of each pump stroke, Pro-Flo
Shift prevents overfilling and saves air and
power, while the pump still performs the
same amount of work.
Wilden has built a laboratory test skid to
mimic plant conditions to compare the ProFlo
Shift's fluid-flow and air-consumption
performance to other AODD pumps. According
to Wilden, pumps equipped with the ProFlo
Shift consume up to 60% less air compared
to a host of popular AODD pumps.
The Pro-Flo Shift technology is commercially
available and can be retrofitted onto
existing pumps, says the company.
A solid way to eliminate contaminants from wastewater
C
SIRO Minerals Down Under Flagship
(Perth, Western Australia; www.csiro.
au/MDU) has developed a method that
uses hydrotalcite formation to simultaneously
remove contaminants from mining
and industrial wastewaters in a single
step. Current wastewater-treatment
processes typically produce lime-based
slurries, often with large amounts of
water, which requires additional treatment.
In contrast, hydrotalcites settle
rapidly out of solution and can be easily
removed using centrifugation, leaving
behind a much cleaner solution.
Hydrotalcites,
Mg6Al2(CO3)(OH)16
[general formula,
.4(H2O)],
consist
ELECTROMAGNETIC SEPARATION
TECHNOLOGY
(Continued from p. 11)
wells, the pulses break oil-water emulsions
(see CE, July 2012, p. 12). The
same technology can effectively rupture
bacteria cells and denature viruses, allowing
its use in increasing algae shelflife,
eliminating bacteria from produced
water, and sanitizing water from aquaculture
ponds.
The company recently announced reof
layers rich in Al and Mg that are
separated by interlayers of negatively
charged ions, such as sulfates. They form
when Al and Mg are present in an ideal
ratio and in a medium with a pH of 6 or
higher. As hydrotalcites form, the Al and
Mg can be partially replaced by other
metals, such as Cu, Pb and Cd, and anions
such as chromate and arsenate can
also be incorporated into the interlayers.
This property makes it possible to trap
contaminants into hydrotalcites, which
can then be easily removed as a solid.
Because mining wastewater often already
contains substantial amounts of
Al and Mg, it is possible to create hydrosults
of a demonstration carried out at
aquaculture facilities in Coachella Valley,
Calif. Operated in a continuously circulated
loop, the EWS technology eliminates
microorganisms from pond water
without the need for chemicals or antibiotics,
helping protect fish and shellfish
from disease. The EWS can also remove
ammonia from the water, by converting
it to nitrates or nitrogen gas. The nitraterich
water can be used to nourish algae,
which is then harvested using EWS
12 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2013
steel industry. The collaboration
will use fermentation technology
developed by Lanzatech,
to reuse the offgases from the
converter, coking plant or blast
furnace processes as nutrients
and a source of energy. The
patented fermentation process
allows steel-plant operators to
make use of the chemical energy
contained in the offgases
(CO, CO2 and H2) for the production
of bioethanol or other
base chemicals, such as acetic
acid, acetone, isopropanol, nbutanol
or 2,3-butadiene.
LanzaTech has been operating
a pilot plant in Auckland,
New Zealand since 2008
utilizing raw steel-mill gases.
In 2012, LanzaTech became
the first company to scale up
gas-fermentation technology
to a pre-commercial level. It
developed and operated two
facilities, each with a capacity
of 300 ton/yr, that convert
fluegas from Baosteel and
Shougang steel plants into
ethanol. The company is now
planning to begin construction
on two commercial facilities in
China in 2013, with production
expected in 2014 (for more process
details, see CE, December
2010; p. 12). ❏
talcites utilizing common contaminants
also present in the wastewater by simply
adjusting their concentration and
adding alkaline compounds to rapidly
increase the pH level, explains CSIRO
scientist Grant Douglas.
Initial applications of the CSIRO process
have focused on treating wastewater
generated from mining and extraction of
uranium at the Ranger mine in the Northern
Territory. The process effectively removes
a range of contaminants, including
uranium, rare-earth elements, transition
metals and anions. Commercialization
of the process is under way with Virtual
Curtain Ltd. (Perth, Australia).
to be pelletized into nutritious feed.
The ability to remove ammonia can
greatly increase productivity in aquaculture
ponds without adding capital
costs, comments Jose Sanchez, OriginOil
vice president of quality assurance
and service. Continuously removing
ammonia allows densities of shrimp
or fish that are twice or three times as
high as with conventional ammonia
handling, without changing pond infrastructure,
Sanchez says.
http://www.wilden.com http://www.csiro http://WWW.CHE.COM
Chemical Engineering August 2013

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