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.

Graphical abstractDifferent 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 full-size imageDownload as PowerPoint slide