Effect of Calcium Addition on Fluidized Bed Agglomeration Caused by Potassium Phosphates
Year: 2024
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Alkali phosphates formed during combustion of agro-biomass have been linked to bed agglomeration in fluidized beds. It has been reported that KH 2 PO 4 can cause agglomeration by melting and gluing quartz bed particles together in a laboratory-scale fluidized bed, whereas K 3 PO 4 was reported to cause agglomeration via a reaction with the quartz bed particles, forming a potassium silicate melt with an approximate composition of K 2 O·4SiO 2 . It has also been reported that limestone (CaCO 3 ) may counteract bed agglomeration. To study this effect, CaCO 3 was mixed with KH 2 PO 4 and K 3 PO 4, and each mixture was fed into an electrically heated bubbling fluidized bed reactor. Quartz sand was used as bed material. The results showed a significant decrease in agglomeration tendency for the mix with KH 2 PO 4 but an increase in agglomeration for the mix with K 3 PO 4 . In both cases, high-melting K–Ca phosphates were formed, yet in the case with K 3 PO 4, the formation led to an increase in the amount of potassium available for further reactions. The “freed” potassium could then react further with either the bed material, forming molten K silicate, or CaCO 3, forming molten K 2 Ca(CO 3 ) 2 . Both compounds glued the bed particles together, while the latter also reacted further with SiO 2, forming x K 2 O· y CaO· z SiO 2 -containing agglomerates. In addition, the formation of an intermediary and previously unidentified reactive K–Ca phosphate was suggested.
Source: Energy & Fuels
Institutions: Åbo Akademi University, Aalto University
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $5,665
Award: G4200700040
OpenAlex ID: W4403458364