Understanding Dry Sorbent Injection (DSI): A Versatile Solution

Dry Sorbent Injection is a post-combustion technology that involves injecting a fine, dry powdered sorbent into a flue gas duct. The sorbent is chosen based on the pollutants it is intended to neutralize. For acid gases, common sorbents include hydrated lime (calcium hydroxide) or sodium bicarbonate. As the fine powder disperses in the hot flue gas stream, a chemical reaction occurs. The sorbent reacts with the gaseous pollutants, converting them into solid salts that can be safely collected downstream in a fabric filter (baghouse) or an electrostatic precipitator (ESP).

The DSI process offers several compelling advantages over traditional air pollution control methods, such as wet flue gas desulfurization (FGD) systems:

• Lower Capital Cost: DSI systems require significantly less capital investment than wet scrubbers, which are large, complex, and require extensive infrastructure.

  
  

• Simplicity and Compactness: The equipment footprint for a DSI system is much smaller, making it an ideal retrofit solution for existing plants with limited space.

  
  

• Operational Flexibility: DSI systems can be easily automated and adjusted to respond to variations in flue gas composition, allowing for a precise dosage of sorbent based on real-time emissions data. This flexibility is crucial for meeting evolving regulatory limits.

  
  

This versatility has made DSI a go-to solution for a wide range of industries, including power generation (particularly in coal-fired boilers), cement production, glass manufacturing, and waste-to-energy plants.

The Unseen Challenge: Handling the Sorbent

While the chemistry of DSI is straightforward, the physical handling of the sorbents is anything but. Materials like hydrated lime, sodium bicarbonate, and activated carbon present a unique set of material handling challenges that can quickly compromise a system if not properly addressed.

• Abrasiveness: While seemingly soft, these fine powders are highly abrasive. Their microscopic, crystalline structures can act like a continuous sandblasting medium, rapidly eroding the internal surfaces of pipes, valves, and feeders. This leads to frequent equipment failure, high maintenance costs, and operational downtime.

• Flow Issues: These fine powders have a low bulk density and can easily become aerated. This can lead to uncontrolled flow, known as "flooding," where the material rushes out of a hopper, overwhelming the conveying system. Conversely, they can also compact and "bridge," forming an arch over a hopper outlet and stopping the flow entirely.

• Hygroscopic Nature: Many sorbents are hygroscopic, meaning they readily absorb moisture from the air. This can cause the material to cake, harden, and clog the conveying lines and storage vessels.

• Precise Metering: The efficiency and cost-effectiveness of a DSI system depend on injecting the exact right amount of sorbent. Too little, and you don't meet emissions targets; too much, and you're wasting expensive material. This requires a feeding system that can provide a precise and consistent dose, hour after hour.

  
  

The Delta Ducon Solution: Engineered for DSI

Delta Ducon's success in the DSI market is built on its deep understanding of these material handling challenges. We don't just provide components; we engineer complete, reliable systems that address the unique properties of each sorbent. Our expertise in pneumatic conveying and our specialized components have become the industry standard for DSI applications.

Precision Feeding and Rotary Valves

The heart of any DSI system is its feeder, and no one understands this better than Delta Ducon. Our proprietary Extreme Rotary Valves are not just simple valves; they are precision-engineered feeding and airlock devices. Unlike conventional valves that fail under the abrasive and cohesive properties of sorbents, our valves feature a robust, through-hardened P-33 Chrome Iron alloy construction. This material, with a Brinell hardness of over 550 BHN, resists the relentless wear of these materials, ensuring the valve maintains its tight seal and metering accuracy for a longer service life. This level of precision is critical for maintaining an optimal stoichiometric ratio (the ideal amount of sorbent needed to react with pollutants), which directly impacts a plant's operational costs.

Optimized Pneumatic Conveying Systems

The method of transporting the sorbent from the storage silo to the injection point is equally critical. For DSI, Delta Ducon utilizes dense or dilute phase pneumatic conveying. . This is a strategic choice. For more information on our pneumatic conveying solutions, visit our Pneumatic Conveying Systems page.

The PERMA/flo™ Advantage

Our commitment to longevity and low maintenance is further demonstrated by our PERMA/flo™ Abrasion Resistant Pipe & Elbows. These components, cast from the same durable alloys as our valves, are a game-changer for DSI systems. The internal design of the elbows promotes a fluid-to-fluid flow, where the material impacts itself rather than the pipe wall, effectively preventing wear and extending the elbow's service life by a factor of three or more compared to standard piping. This prevents the frequent, costly replacements that plague other systems.

Delta Ducon Advantage

Delta Ducon's deep industry knowledge, commitment to quality, and maintenance-friendly design features set us apart. We provide not just a product but a long-term solution that protects your investment and ensures a reliable and sustainable operation. Our leadership in the DSI market is a direct reflection of our dedication to tackling the most difficult material handling challenges and delivering results that matter.

To explore how Delta Ducon can optimize your DSI or other bulk material handling needs, we invite you to visit our Power Industry page or our main website. For a personalized consultation to discuss your specific project, don't hesitate to Contact Us.