Performance optimization of CO2 mineralization: A comparative study of caustic soda and soda ash as pH-risers under high-pressure reactor

Unofficial AI-generated summary based on the public title and abstract. Not an official translation.

🔬研究者:Provides comparative experimental data on pH-riser performance under high pressure, useful for further optimization and kinetic modeling.

🏢実務担当者:Offers guidance on selecting between caustic soda and soda ash for CO2 mineralization processes, considering cost and operational challenges.

🏛政策担当者:Highlights the need for supporting cost-effective CCUS technologies, especially the trade-offs in reagent choice for large-scale deployment.

   Aqueous mineral carbonation is one of the most important methods of permanent CO2 sequestration in Carbon Capture, Utilization, and Storage (CCUS). This is carried out using alkaline pH-risers to neutralize the acidity of carbonic acid (H2CO3) to cause a change in the chemical balance to carbonate ions (CO32-). This paper assesses the different sources of alkalinity with special reference to the performance of caustic soda (NaOH) and soda ash (Na2CO3) under industrial circumstances. It has been shown in experiments that caustic soda is the most effective reagent in quick mineralization. It causes a sudden early increase in pH (about 2.0 to 2.5 units per gram) and maintains a very alkaline pH (pH >12), which are critical to the efficiency of CO2 absorption (95.52 %). Moreover, NaOH has a remarkable stability at high pressure and the rate of change in pH (0.3 ΔpH/gm) does not change at the pressure of 65 bars. Soda ash on the other hand is a moderate buffer that reaches its highest pH at approximately 11.6, with an easily lower absorption efficiency of 72.45%. Soda ash performance improves as the pressure is increased to conserve pressure up to 65 bar, thus making it difficult to use it in high-pressure systems. Optimization of the industry shows that the efficiency is maximized within the temperature regime between 40°C and 60°C, where the accelerated reaction rates resulting decrease in the gas solubility. Furthermore, the best mass transfer rate is 300 rpm that minimizes the CO2 bubble size. Though the stoichiometric superiority of caustic soda 1.0 kg does the work of 1.3 kg of soda ash, it presents severe challenges to operation because of its expensive nature, energy-consuming nature, and corrosivity. Soda ash is also still a feasible option in large scale sequestration due to its 30-40 % lower cost and the fact that it is dry and can be transported easily. Finally, a tradeoff between chemical reactivity, mechanical stability, and scalability of the economic side should be made even in the choice of a pH riser.

• semanticscholar https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/download/1472/1046first seen 2026-07-04 05:30:30