Engineering, Design Drawings, and Specifications
for
Retrofitting Magnetic Separators to the Labadie Plant

Client
Union Electric Company (now Ameren)
P.O. Box 149
St. Louis, Missouri 63166

Completion Date
September, 1995

Project Description
Union Electric was experiencing tramp iron related problems at the 2400 MW (4x600) Labadie Plant. Coal receipts were contaminated with tramp iron. There were no magnetic separators on the receiving system. The existing magnetic separators on the radial stacker reclaim system did not remove a sufficient amount of this tramp material. As a result, the coal feeders and pulverizers were adversely impacted by contaminated coal. To reduce this problem, Union Electric engaged Energy Associates to study the problem and complete the detail engineering, design drawings, and specifications for a retrofitting self-cleaning magnetic separators - which increase the plant's ability to remove tramp iron. Energy Associates assisted Union Electric in this $1.2 million project by preparing the mechanical, structural, and foundation design drawings and the technical and construction specifications.

A total of six self-cleaning magnetic separators were added to the Labadie Plant. Two magnetic separators were added to the receiving system on conveyors N-2 and S-2. The existing four magnetic separators on the radial stacker reclaim system (conveyors N-5A, N-5B, S-5A, and S-5B) were replaced by new, stronger magnetic separators.

For the receiving system, a number of alternatives and arrangements for the magnetic separators were investigated. Manual clean and self-cleaning designs at several locations were investigated. The most convenient design was a self-cleaning, cross-belt arrangement located above grade on the N-2 and S-2 conveyors. Tramp iron is automatically collected into an above grade container. To provide superior tramp iron removal efficiencies, 90 inch square, rectangular core magnets were selected. These magnets are stronger and the magnetic field's envelop is larger than typical circular core magnets. The magnets were located just upstream of the existing “as received” sampling system, as seen in the photograph.

For the reclaim system, the existing base supported magnets were replaced with a more powerful design. To further improve separation, two features were added to the installation. The new reclaim magnets were fitted with an 18 inch long extended, permanent magnets. This magnet extension carries the tramp iron further into the chute, away from the trajectory of the falling coal. Long or irregular shaped items like twisted rebar can be more easily separated from the coal stream. The second feature is a mounting mechanism that allows the plant to adjust the vertical and angular orientation of the magnetic separators. The existing magnets were directly bolted to the chute without any provision for adjustment. The vertical/angular adjustments enables the plant to fine tune the magnet's position to actual conditions, changing clearances as necessary.