(567f) Evaluating Degradation of CO2 Adsorbents in BECCS Processes

The Paris Agreement initiated the development of emission pathways that could limit the global temperature increase associated with atmospheric CO₂ levels. Most pathways include the deployment of Bioenergy with Carbon Capture and Storage (BECCS) – biomass-derived energy with CO₂ capture from the flue gas. Biomass combustion to produce steam and subsequent electricity is a common form of the technology. Current small-scale BECCS projects use liquid amine solvents such as monoethanolamine (MEA) for CO₂ capture. Solid adsorbents could improve BECCS by removing the use of corrosive solvents and lowering the required regeneration energy. While it is hypothesized that adsorbents previously developed for other CO₂ capture applications could be used, there has been minimal research on solid adsorbents specifically in the BECCS application. In a BECCS techno-economic analysis, we conclude that solid adsorbents need lifetimes over two years and exponential degradation decay constants below 5 x 10^-6 cycle^-1 (equivalent to a half-life of 1.3 years) for a levelized cost of carbon below $100/tonne-CO₂. However, it is unclear if current adsorbents meet these stability targets. Here, we experimentally assess the stability of CO₂ adsorbents exposed to common contaminants in biomass combustion flue gases. Through extensive characterization, we gain insight into the mechanism and extent of degradation of each material. The results enable us to evaluate the feasibility of each adsorbent, and we can draw conclusions on which adsorbent characteristics are critical for stability. This analysis is a vital step towards implementing solid adsorbents in BECCS and other CO₂ capture technologies.