In the quest to make carbon capture more economically viable, researchers have been exploring innovative solutions to overcome the substantial economic hurdles that have limited the industrial deployment of CO2 capture technologies. A recent study published in the journal *Carbon Capture Science and Technology* offers a promising avenue for enhancing the cost efficiency of CO2 sequestration, particularly from gases with low CO2 partial pressure, such as flue gas.
The study, led by Robert Kiefel from the Fluid Process Engineering division at RWTH Aachen University in Germany, investigates the use of a spray tower for gas-liquid reactive precipitation in CO2 capture. This approach integrates phase-change absorbents, specifically glyoxal-bis(iminoguanidine) (GBIG), which has shown potential for precipitating HCO3− with low regeneration energy demand.
“GBIG and similar phase-change absorbents present unique operational challenges, such as scaling and clogging in conventional packed-bed columns,” Kiefel explains. “Our study explores the feasibility of using a spray tower to mitigate these issues.”
The research team designed, constructed, and operated a pilot-scale spray tower to test the gas-liquid reactive precipitation process. Contrary to initial expectations, the Rayleigh breakup of liquid jets induced a bimodal droplet size distribution in the lower sections of the tower, highlighting the need for liquid recycling. The study also included a CO32−-precipitating system (Ba(OH)2) and a non-precipitating system (NaOH) for comparative purposes.
All systems demonstrated stable operability in single-pass and batch modes. During liquid recycling, small amounts of solids were entrained to the tower top, but no evidence of scaling or clogging was detected at the orifice plate. This suggests that the precipitated solids are significantly smaller than the orifice diameter.
In the final performance comparison, the GBIG system showed superior CO2 capture efficiency relative to the Ba(OH)2 system. However, achieving this efficiency came at the expense of process kinetics.
The findings of this study could have significant implications for the energy sector, particularly in making carbon capture more economically viable. By addressing the operational challenges associated with phase-change absorbents, this research paves the way for more efficient and cost-effective CO2 sequestration technologies.
As the world continues to grapple with the pressing need to reduce greenhouse gas emissions, innovations like the spray tower for gas-liquid reactive precipitation offer a glimmer of hope. The study not only advances our understanding of CO2 capture technologies but also underscores the importance of continued research and development in this critical field.
“This research is a step forward in our quest to make carbon capture more efficient and economically viable,” Kiefel concludes. “It opens up new possibilities for the energy sector and brings us closer to achieving our climate goals.”