Dual monitoring system for evaluating CCU-based NaHCO3 sorbent in SO2 desulfurization

초록

Sodium bicarbonate (NaHCO3)-based dry sorbent injection is widely used for flue gas desulfurization. In this study, NaHCO3 sorbent was synthesized via a Carbon Capture and Utilization (CCU)-based mineral carbonation process and its SO2 removal efficiency was compared with a commercial NaHCO3 sorbent (C-SBC). To enable accurate SO2 removal efficiency evaluation under dynamic conditions, a dual monitoring system combining a smartphone-based colorimetric vision reader and an IoT-based electrochemical gas sensor was developed. The synthesized sorbent (M-SBC) exhibited a higher specific surface area (19.3 m2 g-1) than C-SBC (10.2 m2 g-1) after thermal treatment at 80 degrees C, resulting in improved SO2 removal efficiency. At 120-160 degrees C, M-SBC_X maintained near-zero outlet SO2 concentration for up to 60 min, whereas C-SBC_X showed rapid desulfurization performance degradation. Continuous gas sensor data enabled precise breakthrough identification, which is not achievable with discrete detector tube measurements. Based on breakthrough criterion of 5% of the inlet concentration, the breakthrough time and capacity of M-SBC_80 were approximately 4.7 times higher than those of C-SBC_80. The integrated system enables real-time breakthrough detection via the gas sensor and reliable concentration validation via the vision reader, providing a robust framework for SO2 monitoring and data-driven optimization of sorbent performance.

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