LDX Solutions Dustex® Circulating Dry Scrubber (CDS)

This technology has been in Great Britain since the 1930’s but didn’t arrive in the United States until 1967. It brings high levels of fine water droplets, hydrated lime, and flue gas together within a circulatory fluidized bed reactor to create ideal reaction conditions.

The Dustex® CDS is one of the most highly efficient and easy to operate systems in existence. The process can achieve >99% SO2 and HCl removal efficiency and is available in a range of sizes. For power plants, single units can be installed at plants up to 300+ MW, and multiple reactor vessels can be utilized for plants larger than 300 MW. 

LDX Solutions Dustex® Circulating Dry Scrubber

CDS Basics

SOx is the general term used for SO2 and SO3.  While SO2 is naturally produced during volcanic activity, the largest source of SO2 emissions is a by-product of the burning of fossil fuels (coal and oil) and the processing of mineral ores (aluminum, copper, zinc, lead, nickel and iron) that contain sulfur compounds.

Sulfur Dioxide
Sulfur Trioxide

The CDS Process

A CDS uses an entrained fluidized bed reactor for contacting the reagent, usually hydrated lime (calcium hydroxide), with sulfur dioxide and particulate laden flue gas. The intensive gas-solid mixing that occurs in the reactor promotes the reaction of sulfur oxides in the flue gas with the hydrated lime particles. The mixture of reaction products (calcium/sulfate), unreacted reagent, and fly ash is carried to a downstream particulate collector (baghouse) where it is separated from the gas stream. The collected material is recycled and reintroduced into the reaction tower. Additionally fresh reagent is continuously added while a small portion of the waste product is removed for disposal. Atomized water spray is injected into the reaction tower for temperature control and to enhance the reaction efficiency of the reagent. 

The CDS Process

Flue gas enters the CDS reactor at the bottom, flows vertically upward through a venturi section and enters an upper cylindrical vessel. The height of the vessel is designed to accommodate the mass of bed-material required to achieve the desired residence time. Independent injection of lime products and water lower flue gas temperature and enhance removal.  Due to the reduced flue gas temperature and the high solids content in the system, mercury (Hg) and other pollutants are also removed in the process.

CDS reactor
Flue Gas Recirculation

Benefits

  • Up to 99% SO2 Removal Efficiency
  • Flexible
    • Multi-Pollutant Removal
      • SO2, SO3, HCl, HF, Pb, Dioxins, Furans
      • Hg Removal
      • Up to 60% NOx removal
    • Fuel Switching
    • Works in High Moisture Applications
  • Low Capital Cost
    • Modular fabrication
    • Simplicity of design with small footprint
    • No slurry systems
    • Exotic Alloys not required
  • Lower Maintenance compared to other technologies
    • No Slurry handling issues
    • Very few moving parts
  • Operational Advantages
    • High recycle rate allows for low reagent consumption
    • Lower power consumption than alternative systems
    • No wastewater stream
CDS System with silo for waste storage

CDS System with silo for waste storage & drive through truck loader

LDX Solutions Dustex® Circulating Dry Scrubber (CDS)

LDX Solutions Dustex® Circulating Dry Scrubber

With over 75 years in Air Pollution Control (APC), LDX Solutions has the expertise to bring solutions to any situation. 

The Dustex® CDS is one of the most highly efficient and easy to maintain systems in existence. It achieves this by not requiring high maintenance mechanical equipment such as abrasion resistant slurry pumps or sludge dewatering devices, in contrast to spray dryers or wet scrubbers. 

The process can achieve >99% SO2 removal efficiency and is available for a range of sizes. Single units can be installed at plants up to 300+ MW, and multiple reactor vessels can be utilized for plants larger than 300 MW. 

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LDX Product & Solutions for a Cleaner World

For A Cleaner World

Trust LDX Solutions to keep your pollution control & pneumatic conveyance systems up & running at peak efficiency. We service all OEM systems with our “best in industry” Aftermarket Parts & Service.