Abstract:

Na₂CO₃-based adsorbent pellets loaded on Al₂O₃ were prepared by graphite-casting method. The effects of calcination temperature on the decarburization characteristics and microstructure of Na₂CO₃/Al₂O₃ adsorbent pellets were investigated. High temperature calcination could significantly improve the decarburization performance of Na₂CO₃/Al₂O₃, and the CO₂ adsorption capacities of Na10Al at 300℃ and 900℃ were 0.621mmol/g and 1.1mmol/g, respectively. The SEM and BET test results showed that the residual graphite on the surface of the pellets could be completely decomposed by calcination at 900℃, which eliminated the adverse effect of the hydrophobicity of graphite, and had a good pore structure and a dense Na₂CO₃ adsorption active site. The loading capacity of Na₂CO₃ (10%—40%, mass fraction) was further optimized, and it was found that Na₂CO₃ was evenly distributed on the surface of Na₂CO₃/Al₂O₃ loaded with 20%, showing the best adsorption performance of 1.62mmol/g. Na₂CO₃/Al₂O₃ loaded with 10% Na₂CO₃ had the best pore structure (specific surface area of 83.417m²/g) and mechanical properties (compressive strength of 95.1MPa). Then ultrasonic cleaning replaced high-temperature calcination to remove graphite, and the structural characteristics of Na₂CO₃/Al₂O₃ loaded with 20% Na₂CO₃ were optimized. The adsorption capacity of Na₂CO₃/Al₂O₃ after ultrasonic cleaning was 1.715mmol/g, the specific surface area was 73.941m²/g and the compressive strength was 52.3MPa. The adsorbent pellets prepared by the optimized graphite-casting method had a potential application prospect.

Key words: Na₂CO₃/Al₂O₃, adsorbent, CO₂ capture, graphite-casting method, ultrasonic cleaning, fixed bed

摘要：

采用石墨盘法制备了负载在Al₂O₃载体上的Na₂CO₃基吸附剂颗粒，研究了煅烧温度对Na₂CO₃/Al₂O₃吸附剂颗粒脱碳特性以及微观结构的影响。高温煅烧可显著提升Na₂CO₃/Al₂O₃脱碳性能，300℃和900℃煅烧下的Na10Al的CO₂吸附量分别为0.621mmol/g和1.1mmol/g。SEM和BET测试结果表明，900℃煅烧可使颗粒表面残留石墨完全分解，消除石墨疏水性所带来的不利影响，具有较好的孔隙结构和密集的Na₂CO₃吸附活性位点。进一步优化了Na₂CO₃（质量分数10%~40%）负载量，研究发现20%负载量的Na₂CO₃/Al₂O₃表面Na₂CO₃分布均匀，展现出最佳的吸附性能1.62mmol/g。10%负载量的Na₂CO₃/Al₂O₃拥有最好的孔隙结构（比表面积83.417m²/g）和力学性能（抗压强度95.1MPa）。之后采用超声波清洗代替高温煅烧去除石墨，进而优化20%负载量的Na₂CO₃/Al₂O₃结构特性，超声波清洗后的Na₂CO₃/Al₂O₃吸附量为1.715mmol/g，比表面积为73.941m²/g，抗压强度52.3MPa。综合考虑优化后的石墨盘法制备的吸附剂颗粒具有潜在的应用前景。

关键词: Na₂CO₃/Al₂O₃, 吸附剂, CO₂捕集, 石墨盘法, 超声波清洗, 固定床