Utilization of semi-dry sintering flue gas desulfurized ash for SO2 generation during sulfuric acid production using boiling furnace

摘要

Highlights ? A process is proposed that desulfurized ash is utilized to produce SO2. ? Thermodynamics and simulation calculations were conducted. ? The kinetics equation describing the decomposition reaction was established. ? The decomposition characteristics demonstrated by TGA and DTF experiments. ? The results of our study provide new insight into the study of SSFGDA reuse. Abstract To effectively solve the problem of reutilizing semi-dry sintering flue gas desulfurized ash (SSFGDA) from steel plants, a new technology is proposed in this paper in which ash is added to a boiling furnace to obtain SO2 during sulfuric acid production. Using thermodynamics and simulation calculations, the high-temperature characteristics of CaSO3 in the ash were preliminarily investigated. By using Kissinger method and the models of Achar and Coats-Redfer, the decomposition kinetics equation of CaSO3 in the ash were obtained. The decomposition characteristics of CaSO3 in the ash were further investigated by thermogravimetric analysis (TGA) and drop tube furnace (DTF) experiments. The results show that at temperatures below 400°C, free water is lost and Ca(OH)2 decomposes, whereas at approximately 460°C, part of the CaSO3 is oxidized. Above 680°C, CaCO3 begins to decompose, with the decomposition process terminating at 790°C. The remaining CaSO3 continues to decompose at approximately 810°C. The activation energy of CaSO3 decomposition is 261.45±77.93kJ/mol; the pre-exponential factor is expressed as ln(A/s?1)=26.13±7.29, and the kinetics equation is dα/dt =2.19×1011