Semi-dry flue-gas desulfurization (FGD) processes abate 99% of atmospheric emissions of sulfur dioxide from coal-fired power plants at the expense of producing daily tones of solid FGD residues containing sulfites, sulfates, carbonates and hydroxides of calcium and magnesium, besides fly-ashes. In this work, a fluidized-bed reactor pilot plant was used for experiments of dry-oxidation of FGD residues aiming at converting sulfites into sulfates in order to upgrade such residues for utilization as raw material to the cement industry. A two-dimensional design of experiments on the plane of feed air temperature and reactor time-on-stream was conducted in the pilot plant generating sulfite conversion data and transient reactor temperature profiles. These data were used for estimating the first-order kinetic parameters of sulfite conversion via non-linear regression following the Maximum Likelihood Principle. The optimized Arrhenius factor and Arrhenius activation energy obtained via the Nelder–Mead Flexible Simplex method were, respectively, 0.001 mol/kg.s.bar and 14146.5 J/mol. This kinetic model allows designing large-scale plants for treatment of semi-dry FGD residues in order to beneficiate it for utilization in the cement industry, avoiding the disposal and environmental costs of landfilling such residues.

中文翻译：

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燃煤电厂烟气脱硫残渣中亚硫酸盐的去除：氧化实验和动力学参数估计

半干法烟气脱硫 (FGD) 工艺可减少燃煤发电厂 99% 的二氧化硫大气排放，但其代价是每天产生大量固体 FGD 残渣，其中含有钙和镁的亚硫酸盐、硫酸盐、碳酸盐和氢氧化物，除了飞灰之外。在这项工作中，流化床反应器中试装置用于对烟气脱硫残渣进行干氧化实验，旨在将亚硫酸盐转化为硫酸盐，以将这些残渣升级为水泥工业的原料。在中试工厂中对进料空气温度和反应器运行时间平面进行了二维实验设计，生成亚硫酸盐转化数据和瞬态反应器温度曲线。这些数据用于通过遵循最大似然原理的非线性回归来估计亚硫酸盐转化的一级动力学参数。通过 Nelder-Mead 柔性单纯形法获得的优化阿伦尼乌斯因子和阿伦尼乌斯活化能分别为 0.001 mol/kg.s.bar 和 14146.5 J/mol。该动力学模型允许设计用于处理半干法烟气脱硫残留物的大型工厂，以便将其在水泥工业中利用，避免填埋此类残留物的处置和环境成本。