Abstract: The carbon peaking and carbon neutrality goals has been concerned, and the current global warming problem caused by excessive carbon dioxide emissions is very serious. In order to alleviate global ecological problems and better achieve the dual-carbon strategy, the research and development of carbon dioxide capture technology is indispensable. In order to enrich the application of static mixers in the field of carbon dioxide absorption, Kenics static mixer (KSM) was used as the enhanced reaction equipment. Based on sodium hydroxide aqueous solution and carbon dioxide (NaOH-CO2) system, the absorption efficiency of carbon dioxide concentration in the range of 25%~33% volume concentration was analyzed using KSM and empty tube structures under different sampling positions and gas-liquid flow rates. The absorption efficiency of carbon dioxide was measured by automatic potentiometric titration. The absorption performance of the KSM structure was compared with that of the empty pipe. The results showed that the maximum absorption efficiency of CO2 in KSM was 72.3% higher than that of the empty pipe. The absorption efficiency of CO2 decreased with the increase of the liquid phase flow rate (QL) at a certain gas phase flow rate (QG) in the empty pipe structure. In contrast, the absorption efficiency of CO2 increased with the increase of QL when KSM elements were installed in the pipe. The volume energy dissipation rate (ε) of KSM structure was analyzed, and it was concluded that the minimum ε was 4.85 m2/s3 when the CO2 absorption efficiency reached more than 90%. The ε increased by 14.7% when total gas-liquid flow rate (QT) varied from 20 L/min to 22 L/min at QG=6 L/min from the first sampling point (Z1) to second sampling point (Z2) in the pipeline. However, the ε increased by 7.83% when QT changed in the same range at QL=14 L/min. The results showed that the change of ε was more affected by QL than QG, and the system energy consumption and reaction were more obvious from Z1 to Z2 in the pipeline. When the gas superficial velocity (UG) was constant, the Darcy friction coefficient (f) decreased with the increase of the liquid superficial velocity (UL), and when the UL was constant, the f decreased with the increase of the UG. The empirical correlation among the UG, UL, and f was obtained by fitting the experimental data with R2=0.999, the correlation deviation ranged from -0.88% to 0.82%.

Key words: static mixer, reinforcement reaction, absorption efficiency, volume energy dissipation rate, Darcy friction coefficient

摘要： 碳达峰和碳中和的“双碳”目标一直备受关注，目前二氧化碳排放过多导致的全球变暖问题十分严重。为了缓解全球生态问题，需要对CO2捕集技术进行研究与开发。为丰富静态混合器在CO2吸收领域的应用，将Kenics型静态混合器(KSM)作为强化反应设备。基于氢氧化钠溶液与二氧化碳(NaOH-CO2)体系，对KSM和空管两种结构下不同采样位置及气液流率的CO2吸收效率进行分析对比。使用自动电位滴定法对CO2吸收效率进行测量。结果表明，在气相流率(QG)为6 L/min，液相流率(QL)为17 L/min，采用KSM的CO2最大吸收效率比空管结构提高了72.3%。一定QG下，空管结构的CO2的吸收效率随QL增加而下降，而管道内装有KSM元件时，CO2的吸收效率随QL增大而上升。对KSM结构的体积能量耗散率(ε)进行分析，管道装备KSM元件时，CO2吸收效率达90%以上，最小ε=4.85 m2/s3。在管道Z1到Z2段，当QG=6 L/min时，气液混合总流率(QT)从20 L/min增至22 L/min，ε增大了14.7%。当QL=14 L/min时，QT从20 L/min增至22 L/min，ε增大了7.83%。ε受QL影响大于QG，在管道Z1到Z2段，系统能量消耗及反应较为剧烈。达西摩擦系数(f)随液相表观流速(UL)和气相表观流速(UG)增加均出现下降趋势。基于实验数据拟合得到UG, UL和f之间的经验关联式，R2=0.999，关联式偏差为-0.88%~0.82%。

关键词: 静态混合器, 强化反应, 吸收效率, 体积能量耗散率, 达西摩擦系数