Amine-based CO2 capture is one of the most mature carbon capture technologies. However, this technology has great energy requirements in particular related to sorbent regeneration. By introducing H2 to the bottom of the desorber, the partial pressure of CO2 is reduced compared to conventional sorbent regeneration (~100% CO2 is produced). This can reduce the required temperature of sorbent regeneration and save energy. In addition, the obtained mixture (H2 and CO2) can be directly used for fuels and chemical production. This idea was proposed by Machida et al. (https://doi.org/10.1021/acssuschemeng.0c02459). The concept is shown in the following figure. The authors used Aspen Plus to simulate the process and reported that the desorber temperature could be reduced significantly (~15 K) by introducing H2 to the bottom of the desorber; this resulted in the improvement of heat recovery. The required energy with heat pump was reduced from 2.91 GJ/ton-CO2 to 2.85 GJ/ton-CO2, when H2 stripping was used, compared to pure CO2 recovery. The reduced desorption temperature is suggested to suppress amine-solution deterioration and corrosion challenges.
