(478b) Onboard Storage and Utilization of Biogas and Power-to-Hydrogen Using Activated Carbon

Renewable fuels such as biogas are becoming highly demanded due to the methane fuel crisis in Europe. However, it can be challenging to obtain high concentrations, > 97 % of methane due to safety limitations for storage and transportation. Activated carbon (AC) is currently used in industry to reduce pressure and increase the temperature needed for methane storage. It is unknown how these same materials used to store methane will fair in binary solutions of CH₄/CO₂ and CH₄/H₂. Nuchar^® activated carbons from Ingevity and Br-318 a compressed activated carbon from Mizzou were chosen due to their large methane storage capabilities of 8.6 and 11.2 mmol/g at 66 bar. These AC also have a high affinity for CO₂ and H₂ with pure adsorption capacities of 19.0 and 1.4 mmol/g, respectively for Nuchar^® and 21.9 and 2.0 mmol/g for Br-318 at 50 bar. In the breakthrough testing, the capacity of CO₂ and CH₄ was reduced by approximately 25 % and 31 % for Nuchar and 27 % and 38 % for Br-318. Therefore, having the highest affinity towards CO₂ reduces the percentage of CO₂ in the storage/ fuel tank to 31 and 22% for Nuchar^® and Br-318 for the first cycle, respectively from the original 50%. While their low affinity for H₂ means that introducing the H₂ into the pipeline will lead to higher energy fuel with only a fraction of the introduced hydrogen being adsorbed onto the AC. The better performance is due to Nuchar having the higher selectivity towards CO₂. The tank was weighed to get the amount in the tank. After four cycles the adsorption reduced the effectiveness, requiring regeneration, to reach full effectiveness.