Hydrated lime is the sorbent of choice for a majority of full scale systems mitigating SO3.  The sites take advantage of the proven removal capabilities, low cost capital systems, and beneficial effects on ash that hydrated lime has to offer.


Factor     Hydrated Lime 
SO3/H2SO4 removal rate      Particulate collection devices will influence effectiveness. In
general, baghouses are more effective than ESPs.

Residence time influences the amount of hydrate required to
control SO3 emissions.

Surface area >21 m2/g is key to achieving cost-effective
control of SO3.

Regulations Hydrated lime has been proven effective for controlling SO3
emissions to 5 ppm and below.  Additionally, Mississippi Lime
has full scale test data proving hydrate's capabilities for
high level SO3 removal (<3 ppm; 90% + removal rates).

Injection Location Flexibility Hydrated lime will cost-effectively remove SO3 at pre- and
post-APH temperatures without the concern of problematic
reaction byproducts that can plug ducts or internal equipment.