Investigation of heat transfer and adsorption in indirect heated adsorbent beds
G. Salazar Duarte1,2, Dr.-Ing. B. Schürer1, Dr.-Ing. C. Voss1, Prof. Dr.-Ing. D. Bathen2 1 Linde AG, München/Germany
2 Universität Duisburg-Essen, Duisburg/ Germany
The cycle time of industrial Temperature Swing Adsorption (TSA) processes usually ranges from several hours to days. The reason for this long cycle time is the usage of purge gas for heating and cooling the system (direct heating), which limits the application of TSA processes to the removal of trace components. In order to reduce cycle time and to separate larger quantities of impurities a more efficient heating strategy has to be considered and a system to remove heat during adsorption has to be implemented. This can be achieved, for example, by using a shell and tube heat exchanger type adsorber. The cycle time can be reduced significantly by the indirect heating and cooling. Also the adsorbed component can be recovered with high purities since the bed is heated indirectly and not with a regeneration gas. During adsorption the released heat can be removed by a heat transfer fluid, which flows through the shell side. The advantages obtained through the indirect heat exchange can be used for the separation of CO2 from industrial flue gases where a relatively large amount of CO2 has to be separated.
It is very important to understand the heating and cooling processes since these can significantly influence the process design of the indirect heated and cooled TSA process. Therefore, an experimental set up was built in order to investigate the heat transfer characteristics as well as the adsorption of indirect heated adsorbers. The preliminary results are encouraging making this process an alternative for carbon capture.