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Activated Carbon Injection System


Activated Carbon Injection System (ACI) for Mercury Control

Activated Carbon Injection is the most established commercial technology for reducing mercury emissions from coal-fired boiler flue gases.  It is a system in which Powdered Activated Carbon (PAC) is pneumatically injected from a storage silo into the flue gas ductwork where it then adsorbs mercury and is collected along with fly ash in the plant’s particulate collector.

  • Capable of greater than 90% control
  • ACI can be used as a stand-alone technology for Hg control or a key part of an integrated solution
  • Equipment requires a small footprint, and can be easily integrated into your facility’s current APC configuration
  • Effective across a wide range of coal and plant configurations

Carbon Injection

Why Partner with ADA to Meet Your Mercury Goals:

ADA’s Activated Carbon Injection Systems will enable your facility to control mercury to achieve compliance. Our ACI system are robust, reliable, and worry-free because the cost of non-compliance is too high.

  • Recognized experts in mercury control with unparellelled industry experience
  • All systems are backed by ADA’s mercury control guarantee
  • Standard, proven designs for quicker delivery and installation
  • Meet rigorous customer and A/E specifications

Key Product Features of an ACI System:

  • Dependable, proven technology
  • Top-quality, utility grade components
  • Standard equipment design to reduce cost and minimize delivery times
  • Shop-fabricated and assembled for quality control and reduced installation time
  • Designed and built to meet  utility and A/E specifications
  • High availability and low maintenance
  • Operational flexibility
  • Fully automated, hands-free operation
  • Fail-safe interlocks and alarms
  • In-house CFD modeling to optimize injection grid design for our customer’s ductwork
  • Clean, dust-free operations
  • Comes with ADA’s mercury control expertise and performance guarantees


  • Project management
  • Project controls and scheduling
  • Formal document control system
  • Full in-house engineering capabilities
  • AutoCAD design
  • CFD modeling using Star-CCM+
  • Extensive experience with A/E firm specifications
  • UL listed panel shop
  • Installation and start-up support
  • Optional system optimization programs available

Standard Features


  • 14-foot diameter, up to 98 feet tall
  • Welded steel construction with structural skirt
  • Roof-mounted 24-inch diameter manway hatch with pressure relief valve
  • OSHA-compliant caged ladder to silo roof
  • Up to three product discharge connections with knife-gate isolation valves
  • Air fluidization system for reliable PAC discharge
  • Fill pipe with strainer and cap
  • Paint: SP-6 prep, epoxy prime and finish paint standard

Bin Vent Filter

  • Pulse cleaned cartridge design
  • 99.999% efficient for particles > 0.5μ

Feed Systems (2 to 3 per silo)

  • Rotary valves to fill feed hoppers
  • Feed hopper
  • Stainless steel volumetric feeder with metering and conditioning augers
    • 480V inverter duty motor, gear reducer
    • Speed adjusted with variable frequency drive (VFD)

Pneumatic Conveying Systems (2 to 3 per silo)

  • Positive displacement blower
  • Wear resistant eductor
  • Automated diverter valve assembly

Truck Unloading Panel

  • NEMA 4X panel with switches, indicating lights and alarms

Power Distribution and Marshalling Panel

  • Shop-mounted in silo electrical room
  • NEMA 4 panel
  • Isolated 480V termination compartment with breakers and VFDs
  • Isolated low-voltage termination compartment
  • DCS terminal blocks for integration with plant controls
  • Optional PLC
  • Shop-wired and tested


  • Redundant guided wire radar transmitters measure PAC level in silo
  • Feed hopper level switch
  • Blower discharge pressure and eductor suction pressure switches
  • Bin vent filter ΔP switch

Silo Skirt Enclosures

  • Lighting and convenience receptacles
  • Space heaters and ventilation fans
  • Skirt interior wall insulation

PAC Distribution & Injection

  • Custom manifolds with isolation valves and flex hoses
  • Custom injection lances with mounting flanges

Common Options

  • PLC controls with HMI (Allen-Bradley)
  • Gravimetric feeders
  • Cost effective regenerative blower
  • Ceramic-lined eductors
  • Deluxe instrument package
  • Wrap around stairs to silo roof


ADA-ES, Inc. has the most complete line of mercury control products in the industry, with unparellelled experience.  To date, we have installed, or are currently installing >75 ACI Systems Performed and have preformed >90 full-scale mercury control demonstrations.  Below are the locations and coal types of operating ACI systems by ADA.