Investigation of thermal desorption characteristics and pilot-scale study of polycyclic aromatic hydrocarbons (PAHs)-contaminated soil during cement manufacturing.

This study encompassed lab-scale thermal desorption experiments and pilot-scale demonstration of soil contaminated with polycyclic aromatic hydrocarbons (PAHs) during cement manufacturing. The lab-scale experiments aimed to investigate the impacts of thermal temperature and residence time on the PAHs removal efficiency, residual PAHs concentration and variation in composition profiles of PAHs. Results showed that at the temperature of 400 ℃ and the residence time of 30 min, the total removal efficiency of PAHs exceeded 99%, with each individual PAH compound exhibited a removal efficiency over 97%. The temperature of 600 ℃ and the residence time of 10 min was found to effectively detoxify PAHs-contaminated soil, satisfying the requirements outlined in the DB11/T 811-2011 standard. Increasing the thermal desorption temperature and residence time resulted in higher total removal efficiency of PAHs and lower residual concentrations. During the pilot-scale demonstration, disposal of PAHs-contaminated soil led to an increase in the concentration of alkali materials and a decrease in the concentrations of sulfur and chlorine. Although there was minor coating probability of coating, this had only a slight impact on operating conditions of cement kiln. The impact of PAHs-contaminated soil disposal on air pollutant emissions, compressive and flexural strengths, water demand for normal consistency and soundness may be deemed insignificant. Our research found that thermal desorption was a viable method for detoxification of PAHs-contaminated soil and the technical route employed in this study was effective. [ABSTRACT FROM AUTHOR]