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Unloading time reduced 50 percent with a floating terminal at PowerSouth’s Lowman Power Plant.

By Mark S. Kuhar

PowerSouth Energy Cooperative has upgraded its Lowman Power Plant on the Tombigbee River near Leroy, Ala., for flue gas desulfurization (FGD) and other quality improvements, including a new barge unloader. Stone producers with a barge-unloading operation can assess this system and adapt it for use in aggregates.

The company used an old gantry rope crane to unload coal from barges for many years. But since the new FGD process requires limestone, now the company has to handle coal and limestone, creating the need for a faster, more efficient and more versatile barge unloading capacity.

In addition, the Tombigbee River level at the Lowman plant fluctuates up to about 35 ft. depending on the season and weather. “This had caused us some real problems over the years,” said Utility Supervisor Mike Barton.

“Crews were forever running up and down steps trying to secure the barges under difficult circumstances. It was a time and safety factor that we just had to live with.”

After investigation, however, it was determined that there was a complete and easy solution to the increased material unloading and river level problems: an E-Crane floating terminal consisting of a 2000 Series E-Crane, two barges (one for the E-Crane and one to support the conveyor), a hopper, a barge-haul system, and a barge-breasting system. The E-Crane is equipped with a 25-yd. bucket and can unload 1,500 tph.

Turnkey Operation
“E-Crane designed and constructed it all for us on a turnkey basis, including all electrical controls and wiring,” said Department Supervisor Tom Noble. “The E-Crane system has cut our unloading time in half, cut our maintenance time dramatically, simplified operation and reduced our costs substantially. Power plants, like most businesses, are always under increasing pressure to reduce costs. The E-Crane system helps to keep our costs as economical as possible.”

Barton agreed. “E-Crane maintenance is simple, quick and easy,” he said. “The E-Crane is much safer and more reliable. No more ropes to change; what a huge time and cost saving that was. And the E-Crane system is easy to operate; so the fatigue factor is less. With the floating terminal, the barges are always at the same level as the E-Crane; so it’s easy to bring them into position, unload them, and move them on.

“I have much happier and more productive crews now,” Barton said. “They like the E-Crane so much they really want to take care of it.”

Perfect Balance
E-Crane’s hydraulically pivoting, mechanically linked boom design keeps the machine in near perfect balance throughout the working range. Having gravity work for you instead of against you reduces horsepower requirements and power consumption up to 50 percent, according to the company.

Five series of E-Cranes are available with outreach up to 165 ft. (50 meters) and duty cycle capacity up to 50 tons, the company said. A central lubrication system and accessible hydraulics simplify maintenance.

E-Cranes’ positive grab control allows for precision grab positioning, while the push-down force ensures full grabs for every cycle. The modular machine design concept allows E-Crane engineers to tailor custom solutions for customers’ needs.

The barge-haul system provides ‘utility grade’ unloading equipment and can move one or two loaded 35-ft. x 195-ft. jumbo barges with a capacity of 1,500 tons. The vector-opposed barge-haul system consists of two opposed winches – one forward, one trailing (upstream/downstream) – that work in tandem with a continuous 7/8-in. diameter steel cable.

The control system uses dual vector drives, commanded by a PLC, to electrically coordinate both winches for maximum barge control. Winch motor speed is monitored continuously by the PLC to eliminate freewheeling or loss of payout control.

The barge can be secured against drifting away from the river cell or dock face by a continuous barge-breasting cable. The system can be operated from inside the E-Crane or from a remote location.

“The E-Crane people were easy to work with – very helpful and cooperative,” Noble said. “The E-Crane was delivered on time, within budget, and worked perfectly right from the start.”

Barton added: “We went to the E-Crane International facility in Galion, Ohio, for several days of training on how to operate and maintain the equipment. Then E-Crane personnel spent a lot of time with us here at our Lowman plant when the equipment was set up and operating. Steve Suter, E-Crane service manager, has been an enormous help.

“I still call him frequently for counsel on various matters. He’s always available and always has the right answer.”

Information for this article courtesy of E-Crane International USA Inc., 1332 Freese Works Place, Galion, Ohio, 419-468-0090