ADM gains total control in elevator upgrade
August 01, 2004
by Emily Buckley
Automation is prime feature of ADM’s facility upgrade at its Logansport, Indiana, U.S. grain elevator
After Archer Daniels Midland’s terminal grain elevator in Logansport, Indiana, U.S., suffered a fire in August 2002 from a bearing failure on top of the elevator, the company was determined to rebuild a state-of-the-art facility, according to Jim Voigt, vice-president of international operations and engineering for ADM’s international grain facilities.
The three prime objectives of the rebuild, which started in April 2003 and fully came on line this January, were to incorporate complete automation, add explosion suppression systems and include a range of hazard monitoring equipment, such as bearing, belt alignment and speed monitors, and bin temperature monitoring.
The facility was brought online to be 100% PLC-controlled, a feature that no other ADM facility of this size can boast.
"Before this facility ran off a control board, so it just made sense to bring back computer control," said Voigt.
The facility installed four industrial computers with programmable logic controllers (PLCs), Allen-Bradley models PLC SLC 505, which was cheaper than hardwiring the entire facility, he noted.
All plant operations start and stop through the computer. Besides allowing for a 15% to 20% savings in labor costs, the automation offers several benefits and is what really makes this facility stand apart.
The system, which includes a graphical interface of the facility, operates and monitors a total of 193 motors for start/stop, overload and run status. Of the motors, 23 have amp readouts and high amp alarms. There are also alarms and shutdowns for 16 motion switches, 32 plug switches, 42 full bin indicators and 90 slide gates with Andco actuators, 59 of which display the percentage that the gate is open.
"The touch screen at each receiving station gives the operator the ability to control equipment and the graphics on the screen will show the flow path from the receiving pit to the bin," said Dale Knapp, project manager. "The load-out equipment can be totally controlled and monitored by the operator at the rail control building."
The system also logs alarms and fan run times and keeps historic trends of amp usage, allowing the facility better control power usage and startup demands on the power supply.
"The best part of this entire upgrade is the automation features — being able to see all trends off the PLC and to see all the failures at each piece of equipment, you can easily troubleshoot problems."
In addition, the controlled receiving and load-out functions allow identity preservation capability, although Voigt said that function is rarely required with Logansport’s routine shipments of corn to Decatur, Illinois for processing or to the Southeast U.S. poultry markets, wheat to export markets and soybeans to Decatur.
Although storage capacity at the elevator, which has 1.2 million bushels (32,700 tonnes) of concrete and 2.4 million bushels (65,300 tonnes) of steel storage for maize, soybeans and soft red wheat, was not increased, the grain handling systems were significantly upgraded.
Four grain handling legs were installed, specifically two 18,000 bph (500 tph) receiving legs and as well as a shipping leg at 40,000 bph (1,100 tph) and a transfer leg of 18,000 bph. Keeping safety as a key focus of the rebuild, all of the legs were installed using open support towers to prevent dust buildup.
For fast grain receiving speeds, the elevator uses three existing receiving systems with an upgraded total unloading capacity of more than 55,000 bph (1,500 tph). Pits 1 and 2 use a shared enclosed conveyor leading to a 20,000 bph (600 tph) leg that can go to any of the steel bins. Pits 3 and 4 each use an enclosed conveyor belt to convey grain from the pits to the legs, each leg is 18,000 bph and can distribute grain to any of the concrete or steel bins.
The load-out system includes a 40,000 bph enclosed reclaim belt conveyor from the concrete elevator and another 40,000 bph enclosed reclaim belt from the steel bins. These belts feed a 40,000 bph leg. The leg can discharge into the gravity screeners or bypass it for direct loading into the shipping bins to avoid excess breakage of grains when screening is not needed on grains for export.
The shipping bins discharge into a 40,000 bph enclosed conveyor that takes the grain to two 4,500-bu (125-tonne) scales located over the rail tracks. Grain is sampled at the discharge of the shipping belt with asampler from Gamet before entering the scales and the sample is conveyed to an on site lab for grading.
SAFETY & MAINTENANCE
The fire in August 2002 was not the Logansport facility’s first, unfortunately. This history meant special attention was given to ensuring safety and maintaining equipment.
Service platforms were installed for all gates, equipment drives and inspection doors for safe, easy access. High wear areas in the leg heads, Y-valves and spouting are lined with ceramic tile and other wear areas are lined with urethane.
The legs have rack and pinion clean out slides in the boots and pressure relief panels in the trunking and heads. Inspection doors were installed on each Y valve for ease of inspecting gates for wear and checking for a proper seal. An explosion suppression system was installed on the legs with isolation systems on the dust collector.
In addition, there are hazard systems monitoring the bearing temps and belt alignment. The monitoring system presents actual bearing temperatures and allows adjustable set points for alarms; touch switches are used for belt alignment. The information from the hazard monitoring system is transferred to the PCs and is displayed on the control screen.
In all, state-of-the-art safety and automation upgrades have made this facility one of the most advanced in ADM’s fleet and in North America.
Mechanical contractor: Borton L.C.
Electrical contractor: J & M Control System
(two 18,000 bph), transfer leg from grain dryer (one 18,000 bph) and shipping leg (one 40,000 bph): Schlagel
Nine enclosed belt conveyors: HiRoller Conveying
Two gravity screens: InterSystems
Two single distributors and one double distributor: Hayes and Stolz
Discharge sampler: Gamet
Explosion suppression X-Pac III system: Fenwal
Motion monitoring and temperature sensors (T-500 HotBus): 4B