Innovations in Storage Silo Floor Design and Operation

Christopher ToomeyFLSmidth 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 consumption40% more material in each truckLess air to filterBetter product uniformityAlmost 100% extraction

Was the Project Successful – YES!• Lower Operating Costs• Cleaner Environment