Inhibition and promotion: The effect of earth alkali metals and operating temperature on particle agglomeration/defluidization during incineration in fluidized bed

Some studies have demonstrated that earth alkali metals promote agglomeration; however, others have shown that they inhibit the generation of agglomeration. The earth alkali metals (Mg and Ca) may cause both inhibition and promotion of agglomeration/defluidization. Therefore, this study focuses on the effect of Mg, Ca and the operating temperature on the agglomeration/defluidization of sodium during incineration in a fluidized bed reactor. The results indicate that the added Mg and Ca inhibit agglomeration and increase the defluidization time. At low Na/Mg and Na/Ca mole ratios, Mg and Ca inhibit defluidization significantly. However, the inhibition reduces as the concentration of Na increases. When the mole ratio (Na/Mg and Na/Ca) exceeds two, the inhibition of Mg and Ca is not apparent. Under these conditions, the operation temperature is the main factor with regard to agglomeration/defluidization. When Mg and Ca are added to reduce the agglomeration/defluidization, both the concentration of Na and operating temperature must be considered.

Different ratios of alkali metal (Na) to earth alkali metals (Mg and Ca) were employed to simulate the agglomeration/defluidization. Low Na/Mg and Na/Ca ratios inhibit the generation of agglomeration/defluidzation, but inhibition declines slowly as the temperature increases. When the ratios Na/Mg and Na/Ca exceeded two, the inhibition was weak. This result indicated that the inhibition by Mg and Ca was almost eliminated with the ratio increases.Figure optionsDownload as PowerPoint slide