Relocating
the South No. 6 Tower
at the
Labadie Plant
Client
Union Electric Company
(now Ameren)
End of Bottom Road
Labadie, Missouri 63055
Completion Date
December, 1996
Project Description
The
4x600 MW Labadie Plant has three stacks. Units No. 1 & 2 each have an
individual stack located directly behind each unit. Units No. 3 & 4 have a common stack,
located between the units. The two flues are placed within an outer shell. As seen in the photo to the right, the
coal reclaim conveyors are routed through the lower portion of the shell. The conveyor take-up for tensioning
these belts was attached to the outer casing of the Unit No. 3-4 stack.
In response to the lower sulfur
requirements of Clean Air Act Amendments, plant fuel was switched to PRB coal
in 1991. PRB coal is dustier and
more reactive than Illinois coal.
As a result, a dust problem became apparent
at the Unit 3-4 stack take-up location.
Belt flexing at the take-up pulleys released fine dust particles, which
became airborne. They were then
swept into the interior of the common stack shell by the natural chimney draft.
The large coal particles fell into a pile, which accumulated at the base of the
shell. The coal fines drifted
upward to accumulate at inaccessible locations within the common stack
shell. There they caused fires and
created an explosive hazard.
The belts were experiencing
tracking problems. Coal was
accumulating on the take-up bend pulleys.
During the winter, this coal froze to the pulleys increasing belt misalignment. The conveyors are relatively long,
approximately 900 feet. They extend
from grade to the surge bin above the plant silos. The misalignment problem
"chewed-up" the edges of the belts, damaging approximately two-thirds
(2/3) of a mile length of belt for the two conveyors.
To
correct these problems, Union Electric engaged Energy Associates to examine the
possibility of relocating the take-up.
Energy Associates investigated alternatives and recommended a
horizontal, gravity arrangement.
The take-up was located at grade where it is accessible. Features to improve maintenance and
clean-up were incorporated into the design. Energy Associates prepared the detail
design drawings, material purchase requisitions, and construction
specifications for this retrofit.
The horizontal take-up is seen in the above photograph taken during the
construction period. The counter-weight
tower is seen to the right.