Characteristics of CO₂ Absorption into Aqueous Ammonia

Abstract

Aqueous ammonia was investigated as a new absorbent of the chemical absorption process for CO₂ capture from combustion flue gas. The effects of the temperature and concentration of aqueous ammonia on CO₂ absorption in a semi‐batch reactor were studied by interpreting breakthrough curves. Raman spectroscopy analysis of CO₂ loaded aqueous ammonia provided concentration changes of bicarbonate, carbonate, and carbamate as well as CO₂ sorption capacity at given time during the absorption with 13 wt% aqueous ammonia at 25°C. It was observed that carbamate formation was dominating at the early stage of absorption. Then, the bicarbonate formation took over the domination at the later stage while the carbonate remained unchanged.

Keywords:

• Aqueous ammonia
• absorption
• CO₂
• bicarbonate
• carbonate
• carbamate
• Raman

Acknowledgment

This research was supported by a grant (DC2‐101‐1‐0‐0) from Carbon Dioxide Reduction and Sequestration Research Center, one of the 21st Century Frontier Programs funded by the Ministry of Science and Technology of the Korean government.