Suitability of Air-Assisted atomizers for spray Tower-Based carbon capture

WoS Article

en

Post-combustion carbon capture plays a significant role in reducing CO2 emissions to address climate change. Spray scrubbing of flue gases is a popular method due to its low operating costs, ease of retrofitting, and ability to handle large flow rates. The efficiency of spray scrubbing depends heavily on the spray characteristics, which requires selecting the right atomizer. This study compares different air-assisted atomizers based on spray properties such as drop size, drop-size distribution, spray cone angle, and atomization efficiency, evaluating their effects on CO2 absorption in a spray column using 30 wt% aqueous Monoethanolamine (MEA) for CO2 scrubbing. High-speed imaging and laser diffraction methods were used to analyze the spray characteristics across various liquid flow rates (10-30 kg/h) and Gas-to-Liquid Ratios (0-14%), while CO2 absorption was examined in a constant-area spray column (0.2 m inner diameter, 1.5 m length) using a simulated flue gas mixture of atmospheric air and 10 mol% CO2. The results indicate that droplet size is influenced by liquid flow rate, atomizer geometry, and gas-to-liquid mass flow rate ratio (GLR). The Sauter Mean Diameter (D32) ranged from 30 to 600 mu m across the tested conditions. To facilitate a more effective comparison of atomizer performance, the total surface area generated per second (Sx), was used. This parameter integrates both liquid flow rate and D32, offering a more comprehensive evaluation of spray characteristics. Additionally, the effects of spray cone angle and column height on absorption efficiency were investigated. The findings reveal that absorption efficiency increases with greater column height and spray cone angle. This is likely due to improved droplet residence time and better gas-liquid interaction. Furthermore, atomizer performance was assessed in relation to atomization efficiency, revealing that among the three tested air-assisted atomizers, the co-flow air blast atomizer demonstrated superior absorption efficiency while also achieving better atomization efficiency compared to the Impinging Jet (SS-IJC) and Central Jet (SS-CJC) external mixing atomizers.

Carbon capture, Spray column, Air-assisted atomizer, Aqueous monoethanolamine, Gas absorption, Column height

2026-02-01

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