Continental Cement Company upgrades cement terminal performance

Our solution began with a barge-mounted FLSmidth DOCKSIDER™ pneumatic barge unloader. This provided a flexible option to unload cement: a key requirement as the site experienced significant changes in river levels. Pneumatic hoses better compensate for these changes compared to mechanical unloaders. The cement was then transported pneumatically through a pipeline.

 

We also provided an FLSmidth Ful-Floor™ reclaim system for Continental’s new storage dome. Finally, a pneumatic transfer system with an FLSmidth Fuller-Kinyon® screw pump to transfer the cement from the dome to the existing loadout facilities.

 

After three years of regular operation, the systems were inspected when the new storage dome was completely emptied. No equipment wear or damage was found, while almost complete cleanout of the new storage dome was achieved.

Continental Cement Co. operates a cement distribution terminal on the Mississippi River at St. Louis, Missouri. A new production line at its plant in Hannibal, Missouri, created a need for more storage at the terminal, and, at the same time, plans for a new bridge for Interstate 70 over the Mississippi River mandated relocation of the existing barge unloading facility to a point 600 ft. downriver. Lastly, as new demand projections were expected to quickly exceed the capabilities of the existing self-discharging barge fleet, it would be necessary to service the terminal with standard 1500 DWT hopper barges. These were the key factors in the owner's decision to proceed with a major expansion and modification of the terminal.

A 330 tph DOCKSIDER pneumatic barge unloader was supplied by FLSmidth to vacuum unload cement from the barges and pressure convey it to the landside storage facilities. Due to significant fluctuation in the river levels, it was required that the barge unloader be installed on a floating equipment barge. The mooring position created a unique opportunity in that, during normal river level conditions, material barges could be berthed on both sides of the equipment barge, so the barge unloader was supplied with two identical vacuum arms, enabling the unloading process to take place from either side.

Cement is conveyed over 1400 ft through a single pipeline to a filter receiver on top of the existing silos. To meet the requirement for greater storage volume, a 40,000 t capacity monolithic dome was constructed, and a FLSmidth Ful-Floor™ fluidised-floor system was supplied to reclaim the cement from storage. The floor was designed to direct material flow to a centre discharge point for discharge to the pneumatic transfer system (FLSmidth Fuller-Kinyon screw pump), located in a tunnel below the dome floor. The aeration blowers, the material convey air compressor, and the power distribution equipment were installed aboveground in a ventilated, sound-attenuated equipment building.

The pneumatic transfer system conveys cement reclaimed from the dome back to the filter receiver above the silos. This process enables the owner to use the same loadout systems, whether the material was stored in the silos or in the dome. A standalone operator interface terminal in the truck loadout control room enables the operator to fully control and monitor the fluidised floor reclaim system and the pneumatic transfer system.

For Continental Cement, selecting a FLSmidth pneumatic conveying systems for its St Louis terminal was practical for the following reasons:

• The barge unloader required operational flexibility, due to river level fluctuation of greater than SO ft. Pneumatic hoses compensate for these fluctuations better than mechanical interfaces.
• The material needed to be conveyed over property that was not owned by Continental Cement. The pipeline allowed for more flexibility in direction and elevation than a mechanical conveyor. Also, the pipeline does not require routine maintenance outside Continental's property boundaries.
• The centre-discharge design of the dome allowed for flexibility in the tunnel direction, while the pneumatic transfer system allowed for flexibility in discharge direction. This was essential given the restrictions presented by the property size, boundary limits, and geotechnical conditions, etc.

 

Continental Cement commissioned the individual systems in phases beginning in 2009, and has been operating all of the systems regularly since 2012. The dome was first completely emptied in 2015, enabling access for inspection, which revealed no equipment wear or damage, and near 100% cleanout.

 

Every terminal has unique requirements and existing conditions that make it impossible to generalise; however, there are pneumatic systems for every terminal process, and the advantages of these systems are consistent for all applications. Pipeline conveying for material transfer offers complete versatility in design and minimal dust control requirements, while fluidised conveying is a low-energy, low-maintenance solution. Lastly, pneumatic systems have fewer moving parts than mechanical alternatives, which improves operational reliability, reduces maintenance time and costs, and improves safety.