VLE measurement and modelling of absorbents for absorption of CO2
Abstract
Two promising solvents were studied for possible use as absorbents in CO2 postcombustion capture. The two solvents tested were 3-(Diethylamino)-1,2-propanediol(DEA-12-PD) and 1-(2-Hydroxyethyl)piperidine (12-HEPP). A third amine N-tert-Butyldiethanolamine (N-tBDEA) was also tested for another project and comparedwith the two main amines.
Ebulliometer was used for measurements of pure DEA-12-PD and 12-HEPP,and then used in regression of the Antoine equations. The plot of the Antoineequations showed that 12-HEPP is the most volatile, while N-tBDEA is the leastvolatile compound, but all the amines tested were less volatile than MEA. VLEmeasurements of binary amine and water systems were also performed, and sampleswere taken. The samples were analyzed and quantified by amine titration.
The Antoine equations and NRTL model of the measured VLE data were carriedout by the in-house program, Parafinder. The model required critical properties,which were estimated from the Joback method, since those properties werenot available experimentally. The result of the NRTL model were evaluated bythe AARD of the total pressure. The AARD provided the fitness of the model tothe experimental data. The AARD of the total pressure for DEA-12-PD, 12-HEPPand N-tBDEA are respectively 1.82 %, 2.46 % and 1.73 %.