[Kinetic analysis of additive effect on desulfurization activity].

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Context:

• Calcium oxide (CaO) is a key sorbent for flue gas desulfurization.
• Understanding factors influencing CaO sulfation kinetics is crucial for optimizing sorbent performance.
• Additives can significantly alter the reactivity and efficiency of CaO-based sorbents.

Purpose:

• To investigate the additive effects of aluminum oxide (A12O3), iron(III) oxide (Fe2O3), and manganese carbonate (MnCO3) on CaO sulfation kinetics.
• To quantify the impact of these additives on surface reaction and product layer diffusion using a modified grain model.
• To elucidate the mechanisms by which additives influence CaO sulfation reactivity.

Summary:

• Thermogravimetric analysis and a modified grain model were employed to study CaO sulfation kinetics with A12O3, Fe2O3, and MnCO3 additives.
• MnCO3 and Fe2O3 were found to enhance initial reaction rates, product layer diffusion, and final CaO conversion.
• The study highlights that while isokinetic temperature is insufficient, rate constants and diffusion coefficients accurately reflect additive effects, potentially linked to unstoichiometric metal oxides catalyzing reactions via crystal defects.

Impact:

• Provides insights into enhancing sorbent utilization in desulfurization processes through strategic additive selection and compounding.
• Identifies MnCO3 and Fe2O3 as effective additives for improving CaO sulfation efficiency.
• Suggests that manipulating reaction conditions and additive combinations can lead to superior sorbent performance.