Development of High Temperature Water Sorbents Based on Zeolites, Dolomite, Lanthanum Oxide and Coke

Methanation is gaining attention as it produces green methane from CO2 and H2, through Power-to-Gas technology. This process could be improved by in situ water sorption. The main difficulty for this process intensification is to find effective water sorbents at useful reaction temperatures (275-400 degrees C). The present work comprises the study of the water sorption capacity of different materials at 25-400 degrees C. The sorption capacity of the most studied solid sorbents (zeolites 3A & 4A) was compared to other materials such as dolomite, La2O3 and cokes. In trying to improve their stability and sorption capacity at high temperatures, all these materials were modified with alkaline-earth metals (Ba, Ca & Mg). Lanthana-Ba and dolomite sorbents were the most promising materials, reaching water sorption values of 120 and 102 mgH2O/gsorbent, respectively, even at 300 degrees C, i.e., values 10-times higher than the achieved ones with zeolites 3A or 4A under the same operating conditions. At these high temperatures, around 300 degrees C, the water sorption process was concluded to be closer to chemisorption than to physisorption.

Automated summary

Methanation using Power-to-Gas technology is gaining attention as it enables the production of green methane from CO2 and H2. In situ water sorption is proposed to improve this process, but the challenge lies in finding effective water sorbents at useful reaction temperatures. This study investigates the water sorption capacity of different materials at temperatures ranging from 25 to 400 degrees Celsius. The results show that modified lanthana-Ba and dolomite sorbents exhibit promising water sorption values, outperforming zeolite sorbents under the same operating conditions.