In the quest for sustainable energy solutions, researchers are constantly seeking innovative ways to capture and store carbon dioxide (CO2). A recent study published in the journal *Energy Science & Engineering* offers a promising approach that could significantly impact the energy sector’s efforts to reduce carbon emissions. The research, led by Quinn Bennett from the Institute for Sustainable Energy & the Environment at Ohio University, focuses on a semi-continuous process for CO2 mineralization using produced water, a byproduct of oil and gas extraction.
The study details a novel method that utilizes flue gas as a CO2 source and produced water as an alkaline source of calcium ions (Ca2+). This process not only captures CO2 but also converts it into stable carbonate products, specifically calcium carbonate (CaCO3), commonly known as calcite. “Operating at a controlled pH allowed for both complete reaction of available Ca2+ and reproducible control of the produced calcium carbonate product,” Bennett explains. This precision is crucial for scaling the process to industrial levels.
The research employed a full factorial design of experiments to study the effects of reaction temperature, pH, and gaseous CO2 concentration on mineralization and CO2 capture rates, as well as the product’s crystalline structure and morphology. The findings revealed a maximum CO2 capture rate of 0.315 ± 0.007 kg per liter per day at 25°C and 25% CO2 concentration. While the CO2 gas to liquid phase mass transport is believed to be the rate-limiting step, the study suggests that with improved reactor design and optimization, the process could be scaled up to pilot scale.
The implications for the energy sector are substantial. By integrating this process with existing industrial operations, such as the chlor-alkali process, companies could potentially reduce their carbon footprint while also generating valuable byproducts. “This semi-continuous mineralization process shows promise for scaling to a pilot scale CO2 capture technology,” Bennett notes. The ability to use produced water, which is often considered a waste product, adds an additional layer of environmental and economic benefit.
The research highlights the importance of creative use of available reactants to improve the economics of carbon capture and storage (CCUS). As the energy sector continues to seek sustainable solutions, this innovative approach could pave the way for more efficient and cost-effective CO2 mineralization processes. The study, published in *Energy Science & Engineering*, offers a glimpse into the future of carbon capture technologies and their potential to reshape the energy landscape.