Coal - Clean Coal Spiral Product Screening

• Fine Sizing Coal at 150 Microns (100 Mesh) and 100 Microns (140 Mesh) 

• Removal of High Ash Fraction from Clean Coal Spiral Product

• Ash Reduction in Clean Coal Spiral Product Circuits

• Minimal Operator Involvement

• Screen Panel Life Exceeding 12 Months

• Reduction in Maintenance Costs for Downstream Screen Bowl Centrifuges

 

Derrick Corporation's patented Stack Sizer technology enhances the ash reduction in clean coal spiral circuits. The Stack Sizer is a multi-deck, high-frequency vibrating screen capable of separations as fine as 75 microns when fitted with Derrick Corporation's high open area urethane screen panels. Several coal companies selected the Stack Sizer for removal of the minus 100 mesh high ash clay fraction from the clean coal spiral product circuits at their preparation plants. 

 

Prior to the Stack Sizer installations, sieve bends were used in an attempt to remove the high ash fraction from the clean coal produced by the spirals. The sieve bends normally produced a clean coal product that was approximately 15 to 17 percent ash. This ash content exceeded the desired ash content of 10 percent or less. 

 

Months of continuous production have confirmed that the Stack Sizer, fitted with Derrick 100 micron urethane screen panels, consistently produces a clean coal fraction that ranges from 8 to 10 percent ash. Currently, each five-deck Stack Sizer operating is producing approximately 33 short tons per hour of clean coal containing about 9 percent ash. This represents a clean coal yield of about 75 percent and an ash reduction of about 11 percent from the feed slurry.

Clean Coal Spiral Flow Diagram

 

 

Coal Feed onto 100 micron Urethane Panel

 

 

Action of Stack Sizer Repulp Trough

 

 

Five Deck Stack Sizers - Clean Coal Spiral Installation