(399d) The Adsorption of Carbon Monoxide at High Temperatures

Many processes, such as steel manufacturing, petroleum refining, fossil fuel combustion, produce carbon monoxide as a byproduct [1]. Whether to ensure the purity of a product or to protect the air that we breathe it is often advantageous to capture that carbon monoxide. CO can be captured using molecular sieves where the CO molecules are adsorbed onto the surface of the sieves where it can be converted to the less harmful CO₂ or desorbed and collected as nearly pure CO later. Unfortunately, the CO gas is often at a high temperature making its capture in this manner difficult. At high temperatures the gas becomes more energetic and the molecular sieves that are currently in use undergo thermal expansion or chemical changes leading to their failure. Because of this, there has been little research done into the absorption of carbon monoxide at extreme temperatures. While there currently no molecular sieves being commercially used that can handle extreme temperature adsorption, there may be untested materials still available.

Preliminary CO adsorption tests [2] were performed at varying temperature on an adsorption column using 3Å Zeolite, 4Å Zeolite, activated carbon, and our novel adsorbent, (named ADX after our authors’ name: Arndt-Davis-Xie adsorbent), as shown in Figure 1. The 3Å zeolite was tested up to 1000°C and found to greatly reduce its adsorbing of carbon monoxide at temperatures over 400°C. The 4Å zeolite was tested to 600°C and suffered the same failing as the 3Å zeolite losing its ability to adsorb CO at 400°C. The activated carbon sample was tested up to 800°C. It also suffered a large drop in adsorption at 400°C but didn’t completely fail to adsorb CO until it reached 600°C. As the temperature increased the carbon and zeolite samples’ ability to adsorb CO decreased. The ADX adsorbent has shown itself to be capable of adsorbing CO at temperatures exceeding 1,000°C. Further research needs to be performed to ascertain to what extent ADX adsorbent can be applied at high temperatures.

References:

[1] Ma, Xiaozhou, Jelco Albertsma, Dieke Gabriels, Rens Horst, Sevgi Polat, Casper Snoeks, Freek Kapteijn et al. (2023). "Carbon monoxide separation: past, present and future." Chemical Society Reviews 52, no. 11 (2023): 3741-3777.

[2] Arndt, L.D. (2024) “Adsorption of Carbon Monoxide for Magnesium Production by Carbothermic Reduction,” M.A. thesis, Dept. Chemical Engineering, University of Minnesota, Duluth, MN, USA.