Article from The Lehigh Reporter  winter 2004 edition

Edmonton Plant Installs Alternate Coal and Coke Unloading System 

In February 2003 the Lehigh Inland cement plant in Edmonton, Alberta converted its kiln firing system from gas to coal, reducing operating costs by $11,000,000 CDN per year. The coal-firing permit, granted by the local environmental authorities, also permitted the use of petroleum coke as a kiln fuel, with the condition a trial be conducted before using petroleum coke on a continuous basis. The purpose of this trial was to ensure the plant could still meet all the environmental operating conditions while using petroleum coke. "The addition of coke to the coal feed is important. Petroleum coke is a byproduct of the oil refining process and has the potential to further reduce the kiln fuel costs," said Paul Khunkun Special Projects Coordinator, Lehigh Inland Cement Limited.

Planning for Dual Purpose The challenge for this trial was how to add the petroleum coke without installing a complete storage and feed system. At the same time the plant also needed an emergency feed system for coal, in the event that the coal unloading and storage equipment should experience an extended shutdown, such as during winter freeze-up conditions. Khunkun and Keith Meagher of Lehigh Inland and Wolfgang Linke of HTC prepared a conceptual proposal for an alternate coal and coke unloading system. This concept utilized a surface mounted feeder to accept loads from highway dump trucks. The proposal was presented to a local company, Canada Conveyor Systems, to prepare general arrangement drawings. A Request For Proposal (RFP) was sent to three suppliers. The proposal asked for a complete system to unload coal and coke from the highway dump trucks and feed this material onto the coal mill feed belt at a controlled rate. European equipment, proposed by the vendors, was far over budget and would take six months for delivery.

Modification Makes Sense The engineers at Canada Conveyor Systems knew of truck unloading feeders, manufactured in the United States, being used in the agricultural industry. "They located a used surplus Heil feeder 500 miles from Edmonton, and presented us with a proposal to convert this feeder to coal and coke unloading," said Khunkun. The key factors considered in the proposal were the timeline for the engineering work, modifications, installation and overall cost of the project. The decision was made to purchase the feeder and modify it for the coal and coke application. In addition, a new drag chain conveyor was purchased to transport the coal and coke from the feeder discharge onto the existing coal mill feed belt. The changes and improvements to the Heil feeder include: Increased holding capacity at the load area of the feeder Addition of TIVAR Polymer sheeting to provide a reduced friction wear surface New chain, sprockets and drag bars An eight foot wide belt conveyor on drag bars with side walls for carrying coal and coke Access panels for maintenance of chain and feeder skirting A belt cleaning brush at the discharge end Air operated vibratory grizzly for control of material sizing A folding steel platform to provide access to the grizzly, vibrator and feeder drive components A pre-finished metal hood over the entire feeder with a plastic curtain door for weather protection and dust control With only minor work remaining to be conpleted on the maintenance platforms and inspection doors on the Heil feeder, the existing coal storage silo feeder belt required repair work. "This provided us with the opportunity to utilize the new feeder to supplement the coal feed from the existing coal storage silo belt," explained Khunkun.

All Systems Go The new Heil feeder system operated as designed during the belt repair period. Once the speed of the feeder was adjusted to not overload the coal mill feed belt, the system ran very well. The Heil feeder maintained coal feed for a three day period while repairs were completed on the permanent system. The alternate coal and coke unloading system is now ready for the petroleum coke trial and is available as an emergency back-up system to feed coal to the coal mill. "We are pleased to report that the system was ready on time and within the budget of $400,000 CDN," Khunkun stated.