Preparation and mechanism analysis of desulfurizer based on pore-structure regulation technology

To address the issue of low calcium utilization in traditional calcium-based desulfurizers, which is primarily caused by pore blockage from the reaction product CaSO₄ hindering gas contact with fresh sorbent, developing highly efficient low-temperature desulfurizers with a rational pore structure has become a key research direction in dry flue gas desulfurization. In this study, based on a sorbent prepared via the hydration of Ca（OH）₂ and fly ash, a novel calcium-based desulfurizer with an optimized ratio of micropores to mesopores was synthesized through the combined action of zeolite （6.5 wt.%） and the organic pore-forming agent diethyl azodicarboxylate （0.5 wt.%）. The results showed that, compared with a commercial calcium-based desulfurizer, the breakthrough sulfur capacity increased by 26.3% and the Ca（OH）₂ utilization rate increased by 33.3%. Characterization revealed that the desulfurizer’s performance depends not solely on specific surface area, but more significantly on its micropore area and mass transfer properties. The incorporation of zeolite created a favorable microporous environment, while the low-boiling-point diethyl azodicarboxylate vaporized during the drying stage, generating mesopores. Adsorption kinetic analysis indicated that the equilibrium adsorption of SO₂ molecules better fits the Langmuir adsorption isotherm model, and the adsorption process follows a pseudo-second-order kinetic model. The entire adsorption process consists of two stages: surface diffusion and micropore diffusion. This desulfurizer offers advantages such as simple preparation, readily available raw materials, and no secondary pollution, providing technical support for more efficient dry desulfurization methods.