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CASE STUDY

Imperial Sugar partners with MAC Equipment
to install continuous dense-phase conveying
when reconstructing sugar refinery in Georgia.

BY SHANE WHITAKER
hen Imperial Sugar Co., Sugar Land, TX,
decided to rebuild the sugar refinery at Port
Wentworth, GA, following a February 2008
explosion and fire, it sought out the best
available technologies to reduce hazards inherent in
sugar production. According to Brian Harrison, vicepresident, technology, who was charged with overseeing the $200 million-plus reconstruction project
that began production in mid-2009, one of its priorities was to determine how to best convey the billions
of pounds of sugar produced, and this led it to investigate the advantages offered by pneumatic conveying systems.
Prior to the incident, the company used mechanical
systems such as bucket elevators and screw and belt
conveyors to transport sugar to the packaging plant.
Historically, these systems have been used in sugar
refineries because they require less power; however,
these systems also have limited flexibility, and if a
plant expands or modifies processes, it can result in
inefficient layouts. And while nearly any maintenance
staff could maintain these mechanical systems, they
can regularly require repairs because of their numerous moving parts and pieces.
On the other hand, pneumatic conveying requires
more power but has fewer moving parts and greater
flexibility for plants with changing needs. Also, the enclosed pipelines protect the material from contamina-

BAKING & SNACK / March 2010

tion and virtually eliminate the breakdown of the product into smaller particles that can present a dust hazard.
Imperial Sugar engineers visited various plants, not
necessarily sugar refineries, to look at conveying systems and to get an understanding and feedback from
people who had worked with pneumatic conveying
over a period of years. The company also talked to different equipment manufacturers during its investigation to confirm the advantages of pneumatic conveying
and to assess how each company would approach its
process challenges, according to Mr. Harrison.
Ultimately, Imperial Sugar selected MAC Equipment,
Kansas City, MO, to construct continuous dense-phase
pneumatic conveying systems for the reconstructed
plant. Dense-phase conveying uses air pulses ranging
from 400 to 1,600 ft per minute. Although dense-phase
is typically a batch process, it can be made approximate
continuous by adding a second vessel; the two vessels alternating between filling and conveying cycles.
The systems installed at Imperial Sugar use extremely
reliable Spheri Valves, which are available exclusively
from MAC Equipment and its parent company Clyde
Process Solutions. Spheri Valves feature dome-shaped
closures mounted on half shafts that are moved through
90 degrees by means of a pneumatic cylinder. The rubber
seal-mounted valves are inflated by compressed air when
closed to obtain a gas-tight closure. When the valve
opens, the seal is first deflated, causing it to retract away

Baking & Snack - March 2010

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