(700c) Scale-up of Modified Amine-Based Sorbent for Passive Direct Air Capture

Direct air capture (DAC) is one of the negative emission technologies that can be employed to potentially drive down atmospheric CO₂ concentrations. Since this technology is less restricted to location, it could potentially separate carbon emissions from distributed sources. A lot of research efforts have been channeled towards developing robust sorbents for capture. However, the next step towards successful commercialization involves a development of versatile structured systems capable of processing large throughput of air with efficient mass transfer and reduced pressure drop.

In this study, our modified amine-based sorbent was washcoated onto a scaled monolith block and evaluated to determine its adsorption performances. A passive air contactor (PAC) was designed and installed in an environmental chamber where wind speed, temperature, and humidity were controlled to simulate different climatic conditions. A fan was used to simulate different ambient wind speeds and linear velocities inside the contactor. The PAC could accommodate one or two sorbent-coated monolith block(s) with the dimensions of 15 cm x 15 cm x 15 cm. The adsorption data was collected under various temperature, relative humidity, and simulated wind speed conditions. After each saturation step, the sorbent-coated monolith block was regenerated under a vacuum at a desorption temperature and the desorbed gas was collected and analyzed to determine its purity and recovery.

The adsorption data from the bench-scale tests was compared with those for powdered sorbent and small monolith blocks obtained. Furthermore, the adsorption isotherm and kinetic models coupled with a fluid flow model were applied to the monolithic structure for the prediction of the adsorption performances. Based on the performances, key performance metrics including overall CO₂ capture efficiency, volumetric productivity, and pressure drop will be presented.