RESUMO
Performance of natural and modified calcium-based sorbents for heavy metals for food waste under oxy-fuel combustion in a lab-scale tubular furnace was carried out. The effects of furnace temperature, sorbents type, and CO2/O2 ratio on adsorption of heavy metals were investigated. Increasing the furnace temperature helped fixing Al in the bottom ash, but increased the volatilization of Zn. The results showed that heavy metals captured by sorbents highly depended on the metals types. Nature and modified CaO had excellent performance for Al capture while CaCO3 could not absorb Al. Neither CaCO3 or CaO could not use as sorbents for the Cr capture. CO2/O2 ratio highly affected the capture of Cr and Zn but had no influence on Al, and the decrease of CO2/O2 ratio would help capturing Cr and Zn. This work contributes to the heavy metals controlled by Ca-based sorbents during municipal solid waste oxy-fuel combustion.
Assuntos
Cálcio/química , Alimentos , Metais Pesados/química , Adsorção , VolatilizaçãoRESUMO
The volatilization of three heavy metals (Cd, Cr and Zn) during food waste and PVC and their blending combustion in N2/O2 or CO2/O2 atmosphere in a lab-scale tubular furnace was investigated. The concentration of heavy metals in combustion ash was decreased with the increment of furnace temperature in most cases. The replacement of 80N2/20O2 by 80CO2/20O2 decreased the volatilization rate of Cd and Cr, but increased Zn. The increased amount of PVC added into food waste led to less content of Zn in combustion ash, 5% PVC added into food waste decreased the volatilization rate of Cr but 15% PVC added led to the higher volatilization. The volatilization rate of Zn in 70CO2/30O2 was significantly lower than in 85CO2/15O2 or 80CO2/20O2. The result contributes to the understanding of heavy metal volatilization during incineration and emission control of MSW oxy-fuel combustion.