Assessment on combustion performance and bottom ash properties of carbon‐rich fraction from coal gasification fine slag co‐combustion with corn straw char

Abstract

In this paper, the co-combustion characteristics of the carbon-rich fraction from coal gasification fine slag and corn straw char were investigated. The combustion performance of the blend was studied by TGA, and the properties of bottom ash samples were evaluated by XRD, SEM-EDS, and ICP-MS. The results showed that the addition of corn straw char (CC) to carbon-rich fraction (RC) can improve the combustibility of RC. The kinetic reaction mechanisms of the blend combustion were described by the diffusion model and chemical reaction order model (D1 and O3). The 40%RC case was recommended because of the lowest reaction activation energy. Hematite (Fe 2 O 3 ), quartz (SiO 2 ), anhydrite (CaSO 4 ), and diopside (Ca(Mg, Al)(Si, Al) 2 O 6 ) were the main mineral compounds in the RC-CC ash. With different compounding ratios of RC-CC, significant variability was observed in the degree of denseness and aggregation on the surface of the blend combustion bottom ash. The heavy metal concentrations (V, Cr, Ni, As, Cd and Pb) in the ash were tested to be in accordance with Chinese soil environmental quality standards, and the co-combustion process had a positive impact on the enrichment of V, Cr, and Ni in the bottom ash to some extent. The results obtained can make a reference for the synergistic utilization of RC-CC, and the treatment and reuse of combustion bottom ash samples.