Activated Carbon Injection

Activated Carbon Injection (ACI)

Storage and Handling Systems

Mercury Capture...

A Continuing Emphasis for U.S. Coal-Fired Power Plants

Stringent government mercury (Hg) emission regulations at the national and state levels require large mercury emission reductions at the nation's 1,100 plus coal-fired plants, which emit approximately 48 tons of mercury per year. Among the few proven mercury emission control technologies that exist, the predominant process is Activated Carbon Injection (ACI). Powdered Activated Carbon (PAC) injection is the only control technology proven to reduce mercury emissions in excess of 90%.

PAC Storage and Handling Systems

The cornerstone of Metalfab's PAC Storage and Handling System is the integration of the company's proven bin activators, activated Posibins™ and "Better-Weigh®" gravimetric feeders. These critical system components are integrated with process controls, instrumentation, knife gate valves, and interconnecting piping, all pre-installed within the skirt area beneath a fully engineered storage silo. This integrated system provides precise PAC metering to the final downstream injection system feeding the flue gas ductwork.

Metalfab successfully combines testing, equipment design, and system integration capabilities to offer fully integrated PAC handling systems directly to large environmental/boiler OEMs who supply complete ACI systems to power plants.


  • Fully Integrated System with Field-Proven Equipment and Performance
  • Unique, Adjustable, Secondary Discharge Baffle
  • Bin Activator Designed to Improve Density of PAC
  • Adjustable Vibration Force on Bin Activators and Distribution Hoppers
  • Significantly Greater Minute-to-Minute Feed System Accuracy
  • No Additional Compressed Air Requirement Beyond Instrument Air
  • Even Draw-Down of PAC from Silo to Feeders
  • Highly Efficient "Better-Weigh®" Gravimetric Screw Feeder with Only Two Moving Parts
  • Simple Screw and Tube Change
  • PLC-Based Controls and Monitoring with Easy-to-Use Touch Screen Displays


  • Delivers Long-Term Reliability with Low Life Cycle Cost
  • Guarantees Continuous Sorbent Flow without Product Compaction and Arching
  • Maintains Consistent PAC Bulk Density without Fluidization
  • Breaks up Compacted PAC that has Settled in Silo During Extended Unit Out-of-Service Periods
  • Reduces PAC Consumption and Operating Costs Compared to Gravimetric Rotary Air Metering Systems
  • Reduces Utility Costs, Maintenance, and Fugitive Dust
  • Permits First-In/First-Out Flow of PAC on Demand
  • Reduces Equipment Downtime and Related Maintenance Costs
  • Allows Greater Flow Range with Rates up to 8400 Pounds per Hour (280CFH)
  • Provide a User-Friendly Interface for:
    • Automated Feed Rate Optimization
    • Batch History and Discharge Data
    • Security Controls with Associated Warnings and Alarms