Experimental evaluation of a 10-kW parabolic trough solar reactor prototype driving Ni-based chemical looping redox cycle with methane for solar fuel production

• Published in: Science China. Technological sciences 2024-12, Vol.67 (12), p.3741-3754
• Main Authors: Jiang, QiongQiong, Cao, YaLi, Sun, Fan, Xing, XueLi, Hong, Hui
• Format: Article
• Language: English
• Subjects: Clean energy; Energy levels; Engineering; Fuel production; Irradiation; Methane; Oxidation; Oxygen transfer; Prototypes; Reactors; Reforming; Solar energy; Solar energy conversion; Synthesis gas; Thermal cycling; Upgrading
• ISSN: 1674-7321; 1869-1900
• DOI: 10.1007/s11431-024-2742-4

Solar fuels can be cost-effectively produced using solar-driven thermochemical processes. Hybridizing thermochemical processes can not only effectively utilize solar energy but also achieve clean conversion of fossil fuels. With this method, the solar energy level can be upgraded, and the irradiation fluctuation can be solved. It is worth noting that solar reactors play an important role in this technology. In this study, we demonstrated a 10-kW parabolic trough solar-driven reactor prototype for methane reforming and solar fuel production. The primary setup of the experimental platform consisted of a trough concentrating solar collector, chemical looping reforming reactors with indirect heat transfer, and associated auxiliary equipment. Experiments on the chemical looping redox cycle were conducted using nickel-based NiO/NiAl 2 O 4 as the OC under different direct normal irradiation (DNI) from 740 to 920 W/m 2 . Under irradiation at approximately 920 W/m 2 , the methane conversion initially increased to 92% before declining to 75% from 0 to 900 s and then to 2500 s. Under these conditions, the syngas concentration increased from 30% to 57% and the solar-to-fuel efficiency reached 59%. The oxygen transfer rate during the chemical looping redox cycle was also experimentally investigated. Cyclic redox cycle experiments were conducted for 540 min of long-term operation to assess the duration and adaptability performance. The fractional oxidation can consistently return to almost 1.0 after each redox cycle, indicating strong reactivity and regenerability when exposed to different levels of DNI. The reactivity of the chemical looping redox cycle during typical autumn and winter days was also investigated and discussed. This study aimed to prove that this 10-kW parabolic trough reactor prototype can harness 500°C solar heat to drive efficient methane reforming, offering a promising avenue for solar fuel production.