Study on the effect of alcohol additives on ammonia decarburization performance and ammonia escape

Abstract

Ammonia carbon capture is characterized by low corrosion, resistance to oxidation and degradation, and low energy consumption for regeneration. However, it also presents challenges such as a slow absorption rate and notable ammonia escape. Current ammonia decarbonization research primarily focuses on the flue gas from power plants, which differs in composition from ship exhaust gas. To address this, we constructed a small carbon absorption test bench and used a mixture of CO₂ and N₂ as the ship exhaust gas. Ammonia solution and alcohol served as absorbents and additives, respectively, to explore the effects of the additive hydroxyl number, the concentrations of the additive and ammonia solution, and the reaction temperature on carbon loading, absorption rate, and ammonia escape. Results indicated that n-propanol was most effective in inhibiting ammonia escape, and a low concentration of ammonia solution was more suitable for absorbing CO₂. Specifically, when the concentration of ammonia was 4% and the concentration of n-propanol was 0.2 mol/L, the cumulative ammonia escape was reduced by 34% compared to the scenario without additives. Additionally, the carbon loading and average absorption rate reached 0.49 mol CO₂/mol NH₃ and 2.33 × 10⁻³ mol·kg⁻¹·min⁻¹, respectively, representing increases of 34.2 and 60.7%. However, as the reaction temperature increased, the effectiveness of n-propanol in enhancing ammonia absorption diminished. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.