Absorption of CO2 and H2S in Aqueous Alkanolamine Solutions using a Fixed-Bed Reactor with Cocurrent Downflow Operation in the Pulsing Flow Regime

摘要

Absorption rates of H2S and CO2 in several aqueous alkanolamines in a cocurrent downflow fixed-bed reactor operated in the pulse flow regime have been measured in order to obtain information on the potential selectivity and on the mass transfer parameters. From these experiments it can be concluded that this type of reactor seems to be very suitable for the selective removal of H2S from acid gases. It was not possible to derive correlations which are always valid for the calculation of the mass transfer parameters in laboratory-scale contactors. The results of the present study in combination with the data published in the literature were correlated with only one unknown parameter in which the influence of the physical properties of the system and the shape and material of the packing were combined. This parameter has to be determined empirically. Small amounts of acid gases in aqueous alkanolamine solutions have a pronounced effect on the properties, such as the foaming behaviour, of the liquid phase. The pressure drops measured in the cocurrently operated fixed-bed reactor were affected substantially by small amounts of acid gases present in the aqueous alkanolamine solutions and up to now this effect could not be explained satisfactorily. For the design of contactors for industrial purposes, detailed scale-up rules are required. In the present study this aspect is not investigated.