Achieving zero CO2 emissions from integrated biomass gasification with CO2 capture and utilization (IGCCU)

Biomass energy plays a crucial role in mitigating carbon emissions. However, the existing gasification technology faces challenges such as releasing undesirable CO2 in the produced syngas. Here we propose a new concept for achieving zero CO2 emissions by integrating gasification with CO2 capture and utilization (IGCCU) for the first time. During lignin gasification, valuable syngas (H2/CO) can be produced, and CO2 in the gaseous products can be simultaneously captured by CaO. After completing the lignin gasification process, the captured CO2 can be effectively converted to CO by switching the carrier gas from N2 to H2. The results show that the entire process achieves zero CO2 emissions with carbonation and hydrogenation process at 400 degrees C and 550 degrees C, respectively. This approach allows a significant reduction in CO2 yield from 0.95 mmol g CaO1 g  1 lignin (benchmark experiment) to nearly 0, using CaO as an adsorbent and catalyst. The disappeared CO2 was converted into 0.95 mmol g CaO1 g  1 of CO, by introducing H2 to the sorbent regeneration stage. Furthermore, excellent cyclic stability has been achieved with zero CO2 emissions after five cycles and consistent 100% CO2 conversion during the CO2 utilization stage.