In a significant stride towards optimizing carbon capture processes, a recent study led by Abdul Raouf Tajik from the Division of Fluid Dynamics at Chalmers University of Technology in Sweden, and the Southwest Research Institute in the USA, has shed light on the influence of different impeller designs on carbonation performances. Published in the International Journal of Thermofluids, the research delves into the effectiveness of radial and axial flow impellers in promoting CO2 capture using various alkaline absorbents, including industrial by-products.
The study, which involved experiments in a lab-scale reactor, revealed that the Rushton turbine, a type of radial flow impeller, showed superior effectiveness in solutions derived from industrial by-products like green liquor dregs and black liquor. However, it came at a high energy cost. On the other hand, the Pitch Blade Down-pumping (PBD) impeller demonstrated superior efficiency in ethanol–NaOH mixtures, where the carbonation process leads to an increase in viscosity.
Tajik explained, “In aqueous green liquor dregs at 400 rpm, down-pumping operation achieved a pH of 8.5 with 13% improved performance at 25% w/v, whereas the up-pumping mode showed a 23% advantage at 5% w/v.” The study also noted significant power number reductions of up to 70% with PBD compared to the Rushton impeller.
The findings underscore the importance of analyzing the optimal impeller design for enhancing CO2 absorption efficiently, considering operational factors and the inherent variations in the process. This is particularly relevant for the maritime sector, which is increasingly exploring carbon capture technologies to reduce emissions and meet stringent environmental regulations.
The unique adaptability of the pitch blade, capable of mode-switching between down-pumping and up-pumping, offers distinct advantages through various stages of carbonation. This adaptability could translate into more efficient and cost-effective carbon capture processes for maritime applications, potentially leading to significant commercial impacts.
As the maritime industry continues to grapple with the challenges of decarbonization, insights from this study could pave the way for more effective carbon capture strategies. The research highlights the need for tailored solutions that consider the specific characteristics of the absorbents and the operational conditions, ultimately contributing to a more sustainable maritime sector.
Tajik’s work, published in the International Journal of Thermofluids, serves as a valuable resource for maritime professionals seeking to optimize carbon capture processes. The study’s findings offer a glimpse into the potential of advanced impeller designs in enhancing the efficiency and effectiveness of CO2 absorption, a critical aspect of the maritime industry’s journey towards a greener future.