Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Comparative SO sub 2 reactivity of CaO derived from CaCO sub 3 and Ca(OH) sub 2

Technical Report ·
OSTI ID:5743604

In an effort to develop a low-cost retrofit technology for control of sulfur dioxide (SO{sub 2}) emissions from coal-fired utility plants, boiler injection of dry calcium-based sorbents to form calcium sulfate (CaSO{sub 4}) has been widely studied. The effects of such parameters as injection temperature, sorbent surface area, and SO{sub 2} concentration on the reaction between the active species, calcium oxide (CaO), and SO{sub 2} are well documented. One such parameter of particular interest is the chemical parentage of the active sorbent. In pilot-scale studies, CaO derived from hydrated lime, Ca(OH){sub 2}, has been found to be more reactive than that from the respective limestone, CaCO{sub 3}. The paper gives results of a comparison of experimental data on sulfation rates of CaO particles derived from CaCO{sub 3} with those derived from Ca(OH){sub 2} using a product layer diffusion control model differing only in the shape of the CaO grain. Both the model and the experimental data indicate slightly higher reactivity for the Ca(OH){sub 2}-derived oxide due to the observed difference in grain shape. The effect is proposed as a contributor to the greater performance of Ca(OH){sub 2} in pilot scale SO{sub 2} removal studies.

Research Organization:
Acurex Corp., Research Triangle Park, NC (USA)
OSTI ID:
5743604
Report Number(s):
PB-89-197776/XAB
Country of Publication:
United States
Language:
English