REACTION OF SULFUR-DIOXIDE WITH LIMESTONE PARTICLES - INFLUENCE OF SULFUR-TRIOXIDE

Measurements of the reaction between SO//2 and limestone added to a fluidized bed of sand at 850 degree C are reported, (a) when the SO//2 entered with the fluidizing gas which was either air or nitrogen with oxygen added, (b) when the SO//2 was generated from coal burnt in the air-fluidized sand. The conversion of limestone to CaSO//4 in case (b) was similar to that in case (a) only when the oxygen concentration in the latter was low. The results are consistent with the hypothesis that an important reaction sequence is oxidation of SO//2 to SO//3 followed by reaction of SO//3 with calcium oxide from the limestone.