MPS89 Coal Mill Modernization Case History: Improving Pulverizer Performance at a 700 MW Power Plant

MPS89 Coal Mill Modernization Case History:
Improving Pulverizer Performance at a 700 MW Power Plant

SAS Global Corporation recently completed a turnkey modernization project on seven MPS89 coal pulverizers supporting a 700 MW opposing wall-fired boiler at a major coal-fired power plant. This comprehensive upgrade restored mill performance, reduced outage duration, and improved long-term reliability through advanced wear materials, patented flow-control technology, and integrated field services.

PROJECT BACKGROUND

The plant had operated its MPS89 pulverizers for decades and had utilized SAS rotating vane wheels and tire shields for nearly 20 years. However, evolving maintenance practices and institutional knowledge loss led to inefficient rebuild procedures, extended outages, and unnecessary component replacement.

During an engineering review, SAS Global identified that major structural components, including ring seats, were being replaced regardless of condition, adding cost and downtime without improving performance. Previous contractors averaged 15 days per mill rebuild.

ENGINEERING ASSESSMENT AND OPTIMIZATION STRATEGY

SAS Global conducted a comprehensive technical evaluation that included:

• Wear pattern analysis
• Component condition assessment
• Classification system review
• Air and fuel flow evaluation
• Maintenance history analysis
  
  

Based on this data, SAS developed a modernization strategy focused on restoring OEM tolerances, improving classification efficiency, mill fuel pipe blance, and upgrading wear systems while minimizing unnecessary capital expenditure.

ADVANCED COAL MILL / PULVERIZER MODERNIZATION COMPONENTS

The modernization package incorporated a fully integrated system of SAS-engineered components, including:

• Patented Closed Race Rotating Vane Wheel
• Patented Cast 15-3 Deflector Liners
• Patented High Spin Static Classifier
• SA2000 Long Service Life Classifier Cone
• Patented Retractable Enhanced Flow Discharge System
• Patent Pending Conical Fuel Particulate Diffuser 
• SAS Long Service Life Tire Shields
• Premium Carbide Overlay Plate mill wall liners
  

These components improved internal coal transport, reduced recirculation zones, enhanced particle classification, improved mill coal discharge pipe balance, and extended wear life in high-abrasion areas.

TURNKEY INSTALLATION AND MECHANICAL UPGRADES

SAS executed the project under a turnkey model, managing engineering, materials, installation, and quality assurance. Scope of work included:

• Roll Wheel and Pressure Frame Restoration
• Patented Closed Race Rotating Vane Wheel Installation
• SAS Long Service Life Tire Shields
• Patented High Spin Static Classifier System Installation
• SA2000 Long Service Life Classifier Cone Installation
• Patented Retractable Enhanced Flow Discharge System Installation 
• Patent Pending Conical Fuel Particulate Diffuser 
• Chromium carbide wall liner installation
• Seal air system upgrades 
• Swing Valve Maintenance
• Pyrite handling refurbishment
• Lube oil and gearbox inspection
  
  

All installations were performed in accordance with OEM clearance requirements to ensure long-term reliability.

REDUCED OUTAGE TIME AND IMPROVED RELIABILITY
Through standardized procedures and experienced field teams, SAS reduced overhaul duration to approximately 10 days per mill—a 33% improvement over previous rebuild cycles. Major repairs, including gearbox replacement and ring seat repair, were completed with minimal impact on outage schedules.

PERFORMANCE IMPROVEMENTS AND BOILER INTEGRATION

Post-modernization results included:

• Improved pulverized coal fineness and fineness control
• Improved air/fuel ratio distribution exiting the mill
• Improved mill discharge pipe-to-pipe fuel balance
• Reduced coarse particle carryover
• Enhanced combustion stability
• Improved operational flexibility
• More uniform burner-to-burner distribution
  

After four mills were upgraded, boiler tuning was completed to fully optimize combustion performance and emissions control.

LONG-TERM VALUE AND REPEAT BUSINESS

Following the success of the initial project, the utility continued the mill modernizations across its other two locations for a total of 20 mills.

Long-term benefits included:

• Lower maintenance costs
• Extended wear component life
• Reduced forced outages
• Improved plant availability
• Increased fuel flexibility
• Reduction in emissions
  

This project demonstrates how strategic pulverizer modernization can extend equipment life while delivering performance comparable to new systems.

WHY CHOOSE SAS GLOBAL FOR MPS MILL MODERNIZATION?

SAS Global’s proven modernization process combines:

• Data-driven engineering
• Patented mill / pulverizer modernization technologies
• Premium wear materials
• Turnkey field services
• Long-term technical support

Our integrated approach helps utilities maximize reliability, efficiency, and return on investment across MPS-style coal mills.

IN CONCLUSION

This MPS89 mill modernization project highlights how advanced engineering, high-performance materials, and turnkey execution can restore, enhance, and modernize pulverizer / mill performance. By partnering with SAS Global, power producers can reduce downtime, improve combustion efficiency, and achieve sustainable operational excellence.