Adsorption-absorption technique for effective CO₂ capture

This paper presents a study on the removal of CO₂ gas from gas mixture (CO₂/N₂) of 14% CO₂ using adsorption onto zeolite 13X in a fluidized bed at 298 K and 1 atm pressure. The effects of static bed height (5–25 cm) and rate of flow of the gas mixture (6–14 L/min) on the breakthrough time were studied. The desorption of CO₂ was performed by absorbing the adsorbed CO₂ molecules using NaOH solution (0.1 M). The absorption process which was accompanied with chemical reaction achieved two objectives. The first was converting CO₂ gas into a valuable substance (Na₂CO₃) which could be used in many industries. The second was the storage of CO₂ gas in what was called a chemical carrier which could emit the gas when it was needed. The effect of static bed height (5–25 cm) on the absorption process in the fluidized bed was also studied. For the adsorption process, the results showed that the breakthrough time increased with decreasing the flow rate but with increasing the static bed height. In the desorption process, the total amount of absorbed CO₂ molecules was 396 mg, achieving a recovery of 90.8% at 5 cm static bed height. Studying the adsorption in a fluidized bed.Using breakthrough curve to estimate the adsorbed amount of CO₂.Studying the effects of operational parameters on the breakthrough time.Performing the desorption by absorption process.Recovering the adsorbed CO₂ molecules. Studying the adsorption in a fluidized bed. Using breakthrough curve to estimate the adsorbed amount of CO₂. Studying the effects of operational parameters on the breakthrough time. Performing the desorption by absorption process. Recovering the adsorbed CO₂ molecules.

本研究针对体积分数为14%的二氧化碳（CO₂）与氮气（N₂）混合气体，采用13X沸石（zeolite 13X）作为吸附剂，在298 K、1 atm压力的流化床中开展CO₂脱除实验。考察了固定床高度（5–25 cm）与混合气体进料流速（6–14 L/min）对穿透时间的影响。采用0.1 mol/L氢氧化钠（NaOH）溶液吸收吸附态CO₂分子以完成脱附过程，该伴随化学反应的吸收过程可实现双重目标：其一，将CO₂转化为可应用于多类工业场景的高价值物质碳酸钠（Na₂CO₃）；其二，将CO₂存储于化学载体中，可在需要时释放该气体。此外还考察了流化床固定床高度对吸收过程的影响。吸附实验结果表明，穿透时间随气体进料流速降低而延长，随固定床高度升高而增加。脱附实验中，当固定床高度为5 cm时，总吸收CO₂量达396 mg，CO₂回收率为90.8%。本研究核心研究内容涵盖：开展流化床吸附实验、通过穿透曲线估算CO₂吸附量、考察操作参数对穿透时间的影响、采用吸收法完成脱附过程并回收吸附态CO₂分子。