Process modelling of Direct Air Capture (DAC) of CO2 using solid amine sorbents

This paper presents a fixed bed reactor system to capture CO2 from ambient air via
Temperature Vacuum Swing Adsorption (TVSA) cycles employing Lewatit® VP OC
1065 amine-functionalized adsorbents. Firstly, a model describing CO2 mixture flow,
mass, and heat transfer with adsorption isotherm model is developed in Aspen Adsorption
environment to study the performance of DAC processes with TVSA. Then, a single
adsorption column is simulated to study both adsorption and breakthrough curves, and
the model is validated with literature results. Secondly, a full DAC model with TVSA
cycle is developed and the results are compared to TVSA cycle with a steam purge in
literature to validate the reliability and simulation capabilities of the software tool. Lastly,
a model of a process capturing 1.1 kilograms of CO2 per day is developed as a base case,
and studies on the energy requirements, capital, and operating costs of the DAC system
are conducted. In addition, sensitivity studies on the model parameters are carried out.
This work stands as one of the first identified modelling studies of TVSA-based Direct
Air Capture and serves as a basis to analyze the feasibility of DAC system deployment
and its relevance in comparison to CO2 capture from point sources