Delta Ducon’s Dominance: Engineering Excellence in the PAC Injection Market

The global focus on air quality control has never been sharper, driven by increasingly strict environmental regulations targeting hazardous air pollutants (HAPs) like mercury, dioxins, and furans. In response, Powdered Activated Carbon (PAC) Injection has emerged as a cornerstone technology for industrial emission control. PAC systems offer a flexible, effective, and often essential method for capturing and removing these toxic contaminants from industrial flue gas streams.

The market for PAC injection solutions is defined by precision, reliability, and the need for components that can withstand one of the most difficult materials to handle in the bulk solids world. For decades, Delta Ducon has been the premier supplier of systems for this critical application. Our century-long heritage in designing and manufacturing specialized material handling equipment provides the foundation for our market leadership, ensuring that our clients consistently meet stringent air quality standards with maximum uptime and efficiency.

The PAC Injection Mandate: Mercury and HAP Control

Powdered Activated Carbon (PAC) injection is a chemical adsorption process used primarily to capture elemental mercury, other heavy metals, dioxins, and furans from the flue gas of combusting facilities. This technology is vital for compliance with strict rules, such as the U.S. EPA’s Mercury and Air Toxics Standards (MATS) and similar regulations worldwide.

The process is deceptively simple:

1. Preparation: PAC, a highly adsorbent material, is stored and precisely metered.

2. Injection: The PAC is pneumatically conveyed and injected into the flue gas ductwork.

3. Adsorption: As the fine PAC particles mix with the hot flue gas, the target pollutants (like mercury) chemically bond to the vast surface area of the carbon.

4. Collection: The PAC particles, now loaded with contaminants, are captured downstream by a fabric filter (baghouse) or electrostatic precipitator (ESP) and removed from the system.

   
   

PAC is highly effective because of its porous structure and massive internal surface area, but its success is entirely dependent on the efficiency of the injection system that delivers it. An uneven or unreliable feed rate will lead to inconsistent pollutant removal, resulting in regulatory violations, while system failures can cause expensive shutdowns.

The Extreme Challenges of Handling Powdered Activated Carbon

While PAC is an environmental hero, it is a material handling nightmare. Its unique physical characteristics present major operational challenges that have consistently defeated systems not specifically engineered to handle them:

1. Extreme Fluidization and Flooding: PAC is an extremely fine powder (often with a particle size around 20 microns) and has a very low bulk density. When aerated—even slightly—it takes on the characteristics of a liquid, making it prone to flooding. This causes material to rush uncontrollably out of hoppers and feeders, leading to severe dosage inconsistencies, which are disastrous for emission control.

   
   

2. Combustibility and Safety: Powdered Activated Carbon dust is highly combustible and carries a risk of dust explosions in confined spaces. Any handling system must be designed to minimize dust escape, prevent static charge buildup, and operate with a low-velocity profile that reduces the risk of creating an explosive dust cloud concentration.

   
   

3. Abrasiveness and Wear: Though light, the crystalline structure of PAC makes it surprisingly abrasive. Over time, it will wear down standard mild steel components, causing leaks, loss of metering accuracy in rotary valves, and eventual system failure.

   
   

4. Hygroscopicity and Caking: PAC tends to absorb moisture, which can cause it to cake or bridge within storage silos and hoppers, leading to frustrating blockages and interrupted material flow.

   
   

Overcoming these complex and often contradictory challenges—controlling a material that wants to fluidize, explode, and abrade simultaneously—requires decades of specialized experience and proprietary engineering.

Delta Ducon’s Market Leadership: Engineered Reliability

Delta Ducon’s legacy in the PAC market stems from a comprehensive approach that prioritizes precision, durability, and safety. Our success is defined by providing complete, customized systems that manage the material from the truck unloading station right up to the final injection nozzle.

The Heart of Precision: Extreme Rotary Valves

The most critical component in any PAC system is the metering device that ensures the exact dosage is fed into the flue gas line. Delta Ducon’s Extreme Rotary Valves are uniquely designed to counter the PAC’s fluidization problem:

• Anti-Flooding Design: Our valves are engineered with a tighter tolerance between the rotor and the housing, drastically minimizing the "blow-back" air leakage from the conveying line. This control prevents the PAC from becoming overly aerated and flooding the system, ensuring consistent dosing accuracy—a non-negotiable requirement for regulatory compliance.

• Abrasion Resistance: The valves are constructed with heavy-duty components and often utilize our proprietary, through-hardened P-33 Chrome Iron alloy, which resists the abrasive wear of PAC, maintaining the tight tolerances necessary for precision metering far longer than conventional materials. This durability translates directly into reduced maintenance and increased system uptime.

  
  

Beyond Components: The Full PAC Injection System

Delta Ducon’s comprehensive solution extends to every element required for a functional and compliant PAC injection system.

• Silo Storage and Unloading: We design and supply material storage silos and unloading equipment that incorporate specialized aeration and agitation systems to prevent PAC from bridging or caking, ensuring reliable gravity flow to the feeder.

• Injection Technology: The final step—injecting the PAC into the ductwork—requires engineered nozzles and lances that ensure maximum dispersion and mixing with the flue gas. Our injection systems are designed to achieve optimal sorbent distribution, maximizing the contact area and ensuring efficient pollutant removal with minimal sorbent consumption.

• Abrasion-Resistant Piping: To combat the material's wear characteristics, we utilize proprietary components like our PERMA/flo™ Abrasion Resistant Pipe & Elbows, which significantly outlast standard steel piping in high-abrasion environments, guaranteeing system longevity.

  
  

Long-Term Partnership and Global Compliance

Delta Ducon has a proven track record of successfully installing complex PAC systems across the globe for major players in the power and heavy industrial sectors. Our consultative approach, backed by a century of engineering excellence, ensures that every system is custom-designed not just to move material, but to meet the client's unique compliance and operational needs. We don't just sell equipment; we sell reliable compliance and operational efficiency.

The PAC market continues to grow, driven by the global imperative to control mercury and other HAPs. As regulations become tighter and the demand for highly efficient, low-maintenance systems increases, the need for a proven partner is paramount. Delta Ducon is that partner, offering the most durable, precise, and reliable PAC handling solutions available.

To learn more about our specific solutions for hazardous material control and other industrial applications, please visit our Power Industry Page. If you are looking to upgrade an existing system or explore a new PAC injection project, our engineering experts are ready to assist you in designing the most efficient solution. You can reach our team directly via our Contact Us page.