Experimental analysis of enhanced absorption of CO2 by NaOH solution in Kenics static mixer
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％.
static mixerreinforcement reactionabsorption efficiencyvolume energy dissipation rateDarcy friction coefficient
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