Reactive transport modeling of mineral carbonation in unaltered and altered basalts during CO2 sequestration

Significance 

The consequences of excessive carbon dioxide generation are beginning to manifest due to intense fossil fuel usage. Global warming and extreme weather among other negative effects are evident around the globe. To large extent, the scholarly community has taken this matter seriously and various counteractive measures have been proposed. For instance, development of green energy systems has garnered pace and electric vehicles have been developed and commercialized among other measures. In addition, carbon sequestration technologies have also been proposed. Of the various carbon sequestration approaches available, carbon capture and storage in deep geological formations has been found to be an effective means to combat excessive carbon emissions; the combination of physical and chemical trapping mechanisms has yielded positive results in terms of CO2 sequestration.

Research has shown that the nature and chemical composition of the host rock dictate its long-term carbon capture capability. Basalt- a rock rich in iron and other metals that react to form stable carbonates via the reaction involving basalt mineralization has also been proposed for CO2 sequestration. Unfortunately, commercial scale implementation is yet to be examined. Also, existing publications have not factored several transport processes in their models.

There is need for excellent predictive models that work over longer time frame so as to comprehend the serpentinization of unaltered basalt that is a common occurrence around the globe. To address this, Professor Ramesh Agarwal at the Washington University together with scientists at China University of Geosciences (Dr. Danqing Liu, Dr. Yilian Li and Dr. Sen Yang) have developed a predictive model in DOE code TOUGHREACT using the data from core-scale static batch experiments and the field-scale Carbfix project. Their goal was to develop a model that could evaluate the mineral carbonation efficiency of unaltered and altered basalt over a longer time frame. Their work has been currently published in International Journal of Greenhouse Gas Control.

The research team established models for the unaltered basalt (flood) and the altered basalt using the DOE reactive transport code TOUGHREACT, which has been widely used in the simulation of fluid flow through pores and fractures in the sedimentary host rocks and wellbore cements. The researchers employed available mineral carbonation volume fraction and distribution with micro-CT scans from the static batch experiment for their model validation. The impact of basalt conductivity and the CO2 injection rate on the CO2 carbonation, porosity/permeability variation and CO2 plume evolution were analyzed.

The authors observed that unaltered basalt has higher carbonation efficiency than altered basalt both in the carbonation rate and in extent due to serpentine kinetic limitations for aqueous phase CO2 injection. In addition, they noted that the carbonates mineralization extent and rate increased with the content of olivine minerals in basalt. Compared to the injection rate, the impact of reservoir conductivity was found to be significant on mineral carbonation in both the unaltered basalt and altered basalt; higher conductivity was more advantageous for CO2 mineralization under certain circumstances.

In summary, a predictive model for evaluating the CO2 carbonation efficiency and distribution in the pore and fractured structure both at core-scale and field-scale under conditions relevant to CO2 injection in unaltered and altered basalt was developed and validated. In an interview with Advances in Engineering, Professor Ramesh Agarwal, the corresponding author, emphasized that the CO2 injectivity rate in basalt should be carefully assessed at sites based on the reservoir conductivity and whether the basalt is altered or unaltered and the extent of alteration. Overall, in the study, a reliable reactive transport model for CO2 sequestration in basalt was developed and validated.

There are many basalt sites around the world. It is very costly to conduct field scale experiments. The laboratory scale experiments provide limited information and are not reliable. The computational model provided by Professor Agarwal and his team can be employed to conduct field scale computations to determine the feasibility and economic viability of CO2 sequestration in basalt at a given site. This work should also provide impetus for further development and refinement of the model.

Reactive transport modeling of mineral carbonation basalts during CO2 sequestration-Advances in Engineering
Figure: Spatial and temporal carbonation distribution of unaltered (flood) basalt (FB) and the altered (serpentinized) basalt (SB) at field scale. Credit (International Journal of Greenhouse Gas Control)

About the author

Professor Ramesh K. Agarwal is currently the William Palm Professor of Engineering in the department of Mechanical Engineering and Materials Science and Director of Aerospace Research and Education Center at Washington University in St. Louis. From 1994 to 2001, he was the Sam Bloomfield Distinguished Professor and Executive Director of the National Institute for Aviation Research at Wichita State University in Kansas. From 1978 to 1994, he was the Program Director and McDonnell Douglas Fellow at McDonnell Douglas Research Laboratories in St. Louis. Dr. Agarwal received Ph.D in Aeronautical Sciences from Stanford University in 1975, M.S. in Aeronautical Engineering from the University of Minnesota in 1969 and B.S. in Mechanical Engineering from Indian Institute of Technology, Kharagpur, India in 1968. Over a period of 45 years, Professor Agarwal has worked in various areas of Computational Science and Engineering – Computational Fluid Dynamics (CFD), Computational Acoustics and Electromagnetics, Computational Materials Science and Manufacturing, and Computational Geo-mechanics and Combustion and their applications to industrial problems in mechanical and aerospace engineering and renewable and clean energy systems.

His recent work has focused on CO2 sequestration in saline aquifers and basalt, Enhanced Oil Recovery (EOR), Enhanced Gas Recovery (EGR), Enhanced Shale Gas Recovery (ESGR), and Enhanced Geothermal Systems (EGS), and chemical and carbonate looping combustion. He is the author and coauthor of over 600 Journal and referred conference publications. He has given many plenary, keynote and invited lectures at various national and international conferences worldwide in over sixty countries. Professor Agarwal continues to serve on many academic, government, and industrial advisory committees.

Dr. Agarwal is an elected Fellow twenty two prestigious societies including the American Society of Mechanical Engineers (ASME), Institute of Electrical and Electronics Engineers (IEEE), American Society of Civil Engineers (ASCE), American Association for Advancement of Science (AAAS), American Physical Society (APS), American Institute of Aeronautics and Astronautics (AIAA), Royal Aeronautical Society, and American Society for Engineering Education (ASEE). He has received many prestigious honors and national/international awards from various professional societies and organizations. Society of Automotive Engineers (SAE) has established the Ramesh Agarwal CFD award in 2018 in his honor. Among the highest honors, he has been the recipient of Time Network/ICCCI Bank NRI of the Year Award (2018), SAE Arnold Siegel Humanitarian Award (2018), ASME Honorary Member (2017) (Highest honor), Honorary Fellowship of Royal Aeronautical Society (2016) (Highest Honor), SAE International Medal of Honor (2015) (Highest honor), AIAA Reeds Aeronautics Award (2015) (Highest honor), Indian Institute of Technology, Kharagpur Distinguished Alumnus Award (2011), SAE Clarence L. (Kelly) Johnson Aerospace Vehicle Design & Development Award (2010) etc.

Reference

Danqing Liu, Ramesh Agarwal, Yilian Li, Sen Yang. Reactive transport modeling of mineral carbonation in unaltered and altered basalts during CO2 sequestration. International Journal of Greenhouse Gas Control, volume 85 (2019) page 109–120.

Go To International Journal of Greenhouse Gas Control

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