New Spectrophotometric Method for Quantitative Characterization of Density-Driven Convective Instability.

Ying Teng,Yang Wei,Pengfei Wang,Yu Liu,Lanlan Jiang

doi:10.3390/polym13040661

Abstract

CO2 convective dissolution has been regarded as one of the fundamental mechanisms to accelerate the mass transfer of CO2 into brine. We present a new spectrophotometric method to characterize the convective instability and measure the dissolved CO2 mass, which enables the real-time quantitative visualization of CO2/brine transport mechanisms. Successive images were captured to identify the finger development regimes, and the convection morphologies were analyzed by the fingers length and affected area. CO2 solubility was experimentally studied, and the results are in agreement with the theoretical calculations. CO2 mass transfer flux was investigated as the Sherwood number changed. The increase in salinity and temperature has a negative effect on CO2 dissolution; here, numerical simulation and experimental phenomena are qualitatively consistent. In general, these findings confirm the feasibility of the method and improve the understanding of the physical process of CO2 convective dissolution, which can help assess the CO2 solubility trapping mass.

Highlights

The Earth’s climate changes as a result of the increase of greenhouse gas emissions, emissions of carbon dioxide (CO2) from burning fossil fuels [1]
Carbon capture and storage (CCS) technology is often considered as a cost-effective solution to mitigate climate change [2]
CO2 dissolution into saline water was observed under transmitted monochromatic light, and a charge-coupled device (CCD) camera was used to capture images

Summary

Introduction

The Earth’s climate changes as a result of the increase of greenhouse gas emissions, emissions of carbon dioxide (CO2) from burning fossil fuels [1]. Carbon capture and storage (CCS) technology is often considered as a cost-effective solution to mitigate climate change [2]. Saline aquifers have been recognized as promising storage sites due to their large capacity and widespread distribution across the world [3]. One fundamental physical phenomenon related to CO2 geological storage in saline aquifers is CO2 dissolution into brine [4]. CO2dissolved brine is 0.1–1% denser than the original brine [6]. A gravitationally unstable system develops with CO2-dissolved brine overlying the original brine, and this leads to density-driven convection and triggers instabilities

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