Experimental study on the preparation of desulfurizer for low temperature dry desulfurization by digesting CaO in urea solution.

Calcium hydroxide (Ca(OH) 2) with outstanding sulfur dioxide (SO 2) adsorption properties was synthesized through the utilization of calcium oxide (CaO) with a urea solution via a digestion method. This innovative calcium-based desulfurizer aims to meet the needs of low-temperature dry flue gas desulfurization in the steel industry. Fixed-bed experiments were conducted to investigate the impact of different water-ash ratios, urea solution concentrations, and digestion time on the desulfurization efficiency and particle structure of the desulfurizers. Sample CAC-2–0.1 U exhibited outstanding desulfurization performance, achieving 100 % removal efficiency, a sulfur capacity of 34.64 mg/g, and a breakthrough time of 142.6 minutes under target flue gas conditions. The sample also displayed a high specific surface area of 22.10 m²/g and demonstrated adaptability under varying operating conditions. Characterization and reaction mechanisms of the desulfurizer were studied using XRD, SEM, BET, XPS, ICP-OES, and Materials Studio software. Experimental data was analyzed through pseudo-first-order and pseudo-second-order kinetic equations, and intra-particle diffusion model. The product's strong adsorption capacity for SO 2 positions it as a highly promising adsorbent for controlling low-temperature flue gas emissions in the steel industry. [Display omitted] • Fixed-bed experiments to obtain optimal digestion conditions for low-temperature FGD. • The addition of urea facilitates the utilization rate of active components. • Suitable digestion can effectively enhance the desulfurizer particle structure. • Urea modification increased the specific surface area of raw quicklime by 15.09 times. [ABSTRACT FROM AUTHOR]