(239a) Experimental Investigation and Simulation of the CO2 Removal with Indirectly Heated and Cooled Adsorbers

Temperature Swing Adsorption (TSA) processes are applied for the removal of impurities from various gas streams. The limiting factor of the TSA process is the regeneration step, which is characterized by long heating and cooling times. To reduce the regeneration time and the energy consumption, indirectly heated and cooled adsorbers were developed [1]. This new TSA process is able to remove higher quantities of impurities, e.g. CO₂ >2 vol-%. Therefore, new fields of application arise, such as CO₂ removal from flue gas or as prepurification unit in a combined membrane - PSA plant for Helium recovery from natural gas. A pilot plant has been built up to investigate the adsorptive CO₂ removal with indirectly heated and cooled adsorbers: Adsorbent inside the tubes and a heat transfer fluid on the shell-side.

A three adsorber process to remove CO₂ from N₂ was realized. The process consists of an adsorption and a regeneration step. The regeneration step was divided into heating, purging and cooling. Using three adsorbers, a continuous process could be established. In this process at least one adsorber was in adsorption, while the others run through the regeneration steps. The temperature profile of the three adsorbers and especially inside one adsorber tube will be presented and discussed. Additionally, the energy consumption and the CO₂ trend during the regeneration steps, heating and purging, will be illustrated.

In a previous work [2], a mathematical model was developed and implemented in COMSOL Multiphysics to describe adsorption experiments in one adsorber tube. This model was modified and expanded to describe the laboratory experiments in a tube bundle adsorber. The results of breakthrough measurements and heating and cooling experiments were taken to validate the model and to adjust model parameters. A comparison between the simulated temperature profile and the CO₂ concentration during regeneration and the experimental values will be presented. Furthermore, the results of a parameter study on the influence of the CO₂ feed concentration and purge gas flow on the process will be discussed.

References:

[1] Mérel J., Clausse M. and Meunier F.: Carbon Dioxide Capture by Indirect Thermal Swing Adsorption Using 13X Zeolite; Environmental Progress, 2006, Vol. 25, No. 4, p. 327-333

[2] Salazar Duarte G.: Carbon dioxide removal from industrial gases using an indirectly heated and cooled temperature swing adsorption process; Ph.D. Thesis, University Duisburg-Essen, 2017