Tuesday, August 4, 2015

Flue Gas Desulfurization (FGD) Slurry: Measuring Density

fluid gas desulfurization
Fluid Gas Desulfurization Using
Non-contact Gamma Density Gauge
courtesy of RONAN
(click to view larger)
Application Note courtesy of RONAN Measurements

Burning pulverized coal produces sulfur dioxide (S02) gas as a by-product. To reduce S02 emissions, wet scrubber flue gas desulfurization systems (FGD's) were installed in many power plants in response to the Clean Air Act of 1990.

Low cost, and highly available, limestone is used as a reagent in FGD's. The limestone slurry scrubs S02 from the flue gas, thus reducing its escape in to the atmosphere. The resulting by-product of this reaction is mixed with air and produces calcium sulfite, which is then filtered and de-watered and reused as ingredients for wall board, fertilizer or cement.

Challenge

Accurately measuring and controlling the slurry density before and after the scrubbing process is difficult because limestone slurry is very abrasive and is very caustic. Because of this, density measurement with in-line gages becomes very difficult and expensive.

Solution

Using a non-contact gamma density gauge, mounted externally to the pipe, keeps the gauge separated from the slurry and protected from the abrasives and caustic chemicals present. Using a non-contact gamma density gauges also results in lower maintenance and lower costs as exotic wetted materials are not needed. Because in this approach, density is directly measured as a mass in a given volume, and not inferred as with other volumetric technologies (inferring density, the measurement is prone to errors because of varying process variables), the accuracy of non-contact gamma density gauges is very high. Finally, no sampling of the slurry is required, eliminating the need for bypass piping.

Summary

Radiometric Measurement provides accurate and reliable solution to measure slurry density, with low cost of ownership.

For more information, or if you have a challenging density measurement application, contact:

BCE
21060 Corsair Blvd
Hayward, CA 94545
Phone: (510) 274-1990
Fax: (510) 274-1999
E-mail: sales@belilove.comwww.belilove.com