Enhanced weathering to capture atmospheric carbon dioxide: Modeling of a trickle‐bed reactor

Abstract

Enhanced weathering (EW) of alkaline minerals can potentially capture CO2 from the atmosphere at gigaton scale, but the reactor design presents great challenges. We model EW with fresh water in a counter‐current trickle flow packed bed batch of 1–10 mm calcite particles. Weathering kinetics are integrated with the mass transfer of CO2 incorporating transfer enhancement by chemical reaction. To avoid flooding, flow rates must be reduced as the particles shrink due to EW. The capture rate is mainly limited by slow transfer of CO2 from gas to liquid although slow dissolution of calcite can also play a role in certain circumstances. A bed height of at least 7–8 m is required to provide sufficient residence time. The results highlight the need to improve capture rate and reduce energy and water consumption, possibly through enriching the feed with CO2 and further chemical acceleration of the mass transfer.

Cu2O nano-flowers/graphene enabled scaffolding structure catalyst layer for enhanced CO2 electrochemical reduction

“…The 'net zero' target act has urged the development of carbon capture and utilisation technologies, including direct carbon capture [1,2], enhanced weathering [3,4], photochemical CO2 conversion [5,6] and electrochemical reduction [7,8]. The electrochemical conversion of carbon dioxide (CO2) has attracted increasing research attention owing to its many advantages, such as moderate reaction temperature, simple reaction setup, and high energy-density fuel products (e.g.…”

Data-driven surrogate modelling and multi-variable optimization of trickle bed and packed bubble column reactors for CO2 capture via enhanced weathering

“…The physics-based TB model is developed by using the pre-validated equations in the work of Billet and Schultes [21,27,28]. The physicsbased PBC model was validated in our previous seawater experiments [11], in which the change of CO 2 concentration in the gas chamber of a PBC reactor was monitored as a function of time; the model was well validated by experimental data.…”

“…During the EW of calcite, the mass transport of CO 2 from gaseous phase into liquid phase is believed to be the rate limiting process [11,21], for which the overall mass transfer coefficient (K OL ) and gas-liquid interfacial area (a G-L ) play a critical role. Fig.…”

“…However, limited research has been done on the EW of minerals in chemical rectors, i.e., TB and PBC, operated at controllable conditions. To the best knowledge of the authors, the two papers of Xing et al [11,21] published in the last two years are the pioneering works in this field. EW of minerals in chemical reactors could accelerate the mineral dissolution rate and reinforce the mass transfer rate of gaseous CO 2 dissolution into water, which is beneficial towards releasing the potential of EW-based large-scale CO 2 capture on the scale of 100-1000 Gt CO 2 per year [20].…”

Global Carbon Dioxide Removal Potential of Waste Materials From Metal and Diamond Mining

“…Engineered solutions for enhancing weathering rates could involve utilising enclosed reactor systems or heap leaching (Darton and Yang, 2020;Hamilton et al, 2020;Xing et al, 2021). For on-site operations and reactor-based weathering systems, several mine-specific considerations need to be addressed for successful deployment in addition to the chemical and kinetic barriers to implementation.…”