日本地球惑星科学連合2022年大会

講演情報

[J] 口頭発表

セッション記号 H (地球人間圏科学) » H-RE 応用地質学・資源エネルギー利用

[H-RE13] 資源地質学

2022年5月25日(水) 10:45 〜 12:15 201B (幕張メッセ国際会議場)

コンビーナ:大竹 翼(北海道大学大学院工学研究院 環境循環システム部門)、コンビーナ:実松 健造(国立研究開発法人 産業技術総合研究所 地圏資源環境研究部門 鉱物資源研究グループ)、高橋 亮平(秋田大学大学院国際資源学研究科)、コンビーナ:野崎 達生(国立研究開発法人 海洋研究開発機構 海洋機能利用部門 海底資源センター)、座長:高橋 亮平(秋田大学大学院国際資源学研究科)、野崎 達生(国立研究開発法人 海洋研究開発機構 海洋機能利用部門 海底資源センター)

12:00 〜 12:15

[HRE13-11] Environmental and techno-economic assessment on local distributed hydrogen production by low-grade aluminum and acidic hot spring water

*Vani Novita Alviani1Noriyoshi Tsuchiya1Nobuo Hirano1 (1.Graduate School of Environmental Studies, Tohoku University)

キーワード:Hydrogen, Hot spring, Aluminum, Tamagawa, Environmental assessment, Techno-economic assessment

Hydrogen is the cleanest burning fuel found abundant in nature with a high energy density of 142 MJ/kg and thus regarded as a future energy carrier. Global hydrogen production mainly involves fossil fuel use, which is not environmentally friendly unless it considers carbon capture storage. Renewable hydrogen production is then becoming a prominent option worldwide. However, challenges on renewables owing to intermittency, seasonal, and geographic constraints have concerned its deployment. Therefore, hydrogen feedstock is required to go hand-in-hand with the best potential of local resources.

We used low-grade aluminum and acidic hot spring reactions to produce hydrogen onsite at Tamagawa hot spring neutralization facility. The low-grade aluminum materials used were aluminum dross and aluminum chips. The acidic hot spring used had extremely low pH (~1) and boiling temperature (~100ºC). The study also involved an environmental and techno-economic assessment for further development on the local scale.

Our results confirmed a potential application of low-grade aluminum and acidic hot springs for hydrogen generation with hydrogen by volume reaching 50-96 wt.%. Aluminum cutting chips had a higher yield than aluminum dross due to its higher aluminum content. The environmental assessment results indicated that low-grade aluminum and acidic hot spring reaction provided lower carbon dioxide emissions and energy consumptions than other methods, which was advantaged from a carbon dioxide reduction of the hot spring neutralization process [1]. The techno-economic assessment resulted in hydrogen cost in our system being slightly higher than other centralized production plants, but the capital cost was the lowest, even with a small plant capacity, which means the system is well-suited for local distributed hydrogen production. The hydrogen cost was within the range of 2.74-16.62 per kg hydrogen, which seemed realistic to satisfy Japan's 2030 target of ~$11.1 per kg (~$1 per Nm3).

One of the potential sites for pilot plant implementation of this local initiative is Semboku City (Akita Prefecture, Japan), where Tamagawa hot springs are located. Semboku City can manage hydrogen fuel for tourism buses operation across renowned Tazawa Lake, Tamagawa Dam, Tamagawa Hot Spring Nature and Ecological Center, and surrounding areas.

[1] Alviani VN, Hirano N, Watanabe N, Oba M, Uno M, Tsuchiya N. Appl Energy 2021;293:116909. doi:10.1016/j.apenergy.2021.116909.