Influence of Salts on the Sulfur Retention of Limestone in Atmospheric Fluidized-Bed Combustors

摘要

Increased utilization of the available CaO can reduce the amount of limestone required for SO sub 2 retention in atmospheric fluidized-bed combustion systems. In laboratory experiments, a pretreatment with inorganic salts, such as NaCl, CaCl sub 2 , or Na sub 2 CO sub 3 , has been found to be an effective method of improving the CaO utilization. This report provides quantitative information on the effectiveness of the same sulfation-enhancement salts in reducing the limestone requirements in an atmospheric fluidized-bed combustor (AFBC). Some laboratory experiments indicated that only 0.1 mol % of salt was required to produce the structural changes in the limestone necessary to increase the CaO utilization. In contrast, the AFBC runs indicated that as much as 2.0 mol % salt was required to obtain a significant increase in the CaO utilization. The increased utilization of the salt-treated limestone in the AFBC reduced the total amount of limestone needed to meet the EPA emission standard for sulfur dioxide to one-half of that required when no treatment is used. (ERA citation 06:030466)