Conquering CO2 emissions: advanced capture from aggressive industrial streams

초록

Industrial flue gases often contain elevated temperature and moisture, both of which can reduce the effectiveness of adsorption-based carbon dioxide capture. This is an important challenge because many previous studies have focused on dry or moderate operating conditions rather than realistic industrial streams. In this work, a continuous two-bed carbon dioxide capture system based on vacuum swing adsorption was developed and optimized using nitrogen-doped activated carbon prepared from industrial phenolic resin waste. A Taguchi design of experiments was used to evaluate the effects of inlet carbon dioxide concentration, feed flow rate, adsorbent mass, and vacuum pressure on capture efficiency, product purity, recovery, and adsorption capacity. Under the optimized condition of 30% carbon dioxide, 4.5 L/min feed flow, 110 g adsorbent, and 2 kPa vacuum pressure, the system achieved 94.88% capture efficiency, 97.5% purity, 87.19% recovery, and 1.899 mmol/g adsorption capacity. When the nominal feed gas temperature increased from 300 to 700 °C, the gas was rapidly cooled to about 28–30 °C before entering the adsorption bed, and the system still maintained more than 96% purity, while adsorption capacity increased slightly from 1.82 to 1.903 mmol/g. In contrast, increasing moisture above 1 vol% reduced performance, and at 10 vol% water vapor the adsorption capacity decreased to 1.607 mmol/g, with purity and recovery falling to 86.5% and 53.3%, respectively. Regeneration at 120 °C restored performance most effectively under wet conditions. The results show that continuous adsorption-based carbon dioxide capture can remain highly effective under aggressive industrial feed conditions when process parameters and regeneration conditions are properly controlled. The novelty of this work lies in the combined optimization and realistic-condition evaluation of a continuous two-bed system using waste-derived nitrogen-doped activated carbon. The results provide valuable insights into process design and scalability for industrial decarbonization applications.

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