COX-free LOHC Dehydrogenation in a Heatpipe Reformer Highly Integrated with a Hydrogen Burner

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2022-12, Vol.449, p.137679, Article 137679
• Main Authors: Badakhsh, Arash, Song, Donghyun, Moon, Seongeun, Jeong, Hyangsoo, Sohn, Hyuntae, Woo Nam, Suk, Soon Kim, Pyung, Hui Seo, Ji, Kim, Yongwoo, Lee, Jaeyong, Woo Choung, Jin, Kim, Yongmin
• Format: Article
• Language: English
• Subjects: Autothermal reactor design; Heat transfer; Heatpipe reformer; Hydrogen combustion; LOHC dehydrogenation; Phase-change material; Thermochemistry
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.137679

This article elucidates the design and operation of a thermochemical methylcyclohexane dehydrogenator closely integrated with a hydrogen burner. The as-developed module offers solutions for COX-free hydrogen storage and release in on-board or mobile applications. [Display omitted] •Exothermic H2 combustion is thermally coupled with endothermic MCH dehydrogenation.•A LOHC reformer with homogenized temperature is developed.•Maximum dehydrogenation and reforming efficiencies of 13% and 80% are obtained.•Exhaust heat loss is reduced by 150% using the sleeve-type H2 burner.•Our design offers solutions for COX-free H2 release in on-board applications. We introduce a thermally self-sustained reactor concept highly integrated with a heat source to produce hydrogen (H2) stored in methylcyclohexane (MCH), the liquid organic hydrogen carrier (LOHC) with the highest technological readiness. This work is prompted to promote the use of LOHC for COX-free H2 production for on-board or mobile applications. To this end, the heat-pipe dehydrogenator, an H2 burner, and a thermal management module are developed. We have performed a numerical simulation to optimize reactor wall materials and configuration and experimentally tested it to reveal the feasibility of such a highly integrated system to maintain uniform reaction temperature at 320 – 360 °C, optimal for MCH dehydrogenation. In the proposed design, the heat required for the reaction is provided by combustion of a part of released H2, and transferred via a gas-liquid organic phase-change material (PCM). In the as-developed H2 generator with 50.4 NLH2/h (equivalent to 138.5 WLHV-basis), we achieve a high reforming efficiency of 80% with an MCH conversion of >99.7%. We expect the as-developed system to be a stepping stone to expand the use of LOHC in versatile applications requiring carbon-free H2 storage and production after further engineering efforts to enhance heat recovery and thermal circulation.