📋 Case Study

Pacific Northwest Wheat Export Terminal Conveyor Segregation Control

Size- and protein-based segregation causing grade noncompliance in railcar loading

🏗️ Project Overview

Bellingham, WA terminal handling 4.2M metric tons/year of export wheat

🎯 Challenge

Size- and protein-based segregation causing grade noncompliance in railcar loading

🔧 Design Approach

Installed dual-feed transfer chutes with adjustable splitter vanes + downstream recirculation loop with blending screw

📐 Design Diagram

AI-generated project design illustration

📐 Key Calculations

Elutriation Velocity

√[(4×g×(ρ_p−ρ_a)×d_p)/(3×C_d×ρ_a)]

Result: 3.1 m/s

Sets max air velocity in transfer zone

Blending Residence Time

V/Q

Result: 42 sec

Ensures >95% homogeneity per ASTM D6951

📊 Results

Grade compliance improved from 78% to 99.4%; railcar rework incidents dropped from 11 to 0.7/month

💡 Lessons Learned

• •Trajectory-controlled discharge eliminates cascade segregation
• •Blending residence time must exceed 40 sec for hard red spring wheat

✅ Key Takeaways

• 1Trajectory-controlled discharge eliminates cascade segregation
• 2Blending residence time must exceed 40 sec for hard red spring wheat