Innovations in
Storage Silo Floor
Design and
Operation
Christopher Toomey
FLSmidth Inc.
The Plant – British Columbia, Canada
Background Information
• Plant Constructed in 1956
• Modernization Commissioned in 1999
– New dry pyro line with 5-stage precalciner
– 40,000 tons of clinker storage
– New 3,000 tpd cement grinding mill
– New 7,500 ton cement storage silo
• Plant Capacity, Design: 1,000,000 tpy
• Plant Capacity, Optimized: 1,150,000 tpy
Task in 2005
• New Storage Required
– Cement
– Fly ash
• Required Solution
– Meet the design constraints of the plant
– Promote corporate sustainability … GO GREEN
Cement Silo Design Constraints
• 10,000 tons Required
– Accommodate additional production
– Load larger barges in fleet
• Flexible Discharge Capability
– Bulk truck trailers to local market
– Railcars to United States
– Barges to United States
Fly Ash Silo Design Constraints
• 4,000 tons Required
– Accommodate demand of local concrete
market
• Bulk Truck Loading Capability
Additional Silo Design Constraints
• Low Height to Diameter Ratio
– Poor site soil conditions
• Common Foundation for Both Silos
– Limited space
• Complete Silo Extraction (Cleanout)
– Avoid cement contamination
Promote Corporate Sustainability
• Minimize Energy Consumption
• Improve Logistics/Minimize Truck Traffic
Silo Ideas Considered
• Conventional 60 Degree Cone
• Central Inverted Cone
• Fully Fluidized Random Flow
Conventional 60 Degree Cone
• Wasted Space Near
Bottom of Silo
• Civil Engineering
Considerations
Central Inverted Cone
• High Construction
Cost
• Loss of Storage,
Increased Silo
Height
Fully Fluidized Random Flow
• Small Aeration Area
– Low energy
consumption
– Smaller venting
requirement
– Less fluid, denser
material discharge
• Maximum Storage,
Lower Height
Silo Extraction Design
• 18.5 kW aeration
blower
• 5.5 kW discharge
blower
• Random selective
aeration
• 1/10 energy
consumption versus
standard design
Silo Extraction Design
Cement Silo Aeration
Fly Ash Silo Aeration
The Result
“E” Fly Ash Silo
“D” Cement Silo
Was the Project Successful?
1/10th energy consumption
40% more material in each truck
Less air to filter
Better product uniformity
Almost 100% extraction
Was the Project Successful – YES!
• Lower Operating Costs
• Cleaner Environment