Three-dimensional numerical study on a novel parabolic trough solar receiver-reactor of a locally-installed Kenics static mixer for efficient hydrogen production

• Published in: Applied energy 2019-09, Vol.250, p.131-146
• Main Authors: Cheng, Ze-Dong, Men, Jing-Jing, Liu, Shi-Cheng, He, Ya-Ling
• Format: Article
• Language: English
• Subjects: Computational fluid dynamics; Field variable uniformity; Hydrogen production; Kenics static mixer; Monte Carlo ray-tracing method; Solar receiver-reactor
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2019.04.179

•A novel solar receiver-reactor of a locally-installed Kenics static mixer is proposed.•A three-dimensional comprehensive model was established for solar receiver-reactors.•Effects of solar flux nonuniformities and static mixers were studied comprehensively.•Better comprehensive characteristics and performance are obtained in novel systems.•The mechanism is that uniformities of a series of key field variables are improved. In this paper, a novel parabolic trough solar receiver-reactor (PTSRR) system of a locally-installed Kenics static mixer (KSM) is proposed for efficient solar thermal hydrogen production. A three-dimensional comprehensive model was established for PTSRRs of the methanol-steam reforming reaction (MSRR) for hydrogen production, by combining the Finite Volume Method and the Monte Carlo ray-tracing method with a MSRR comprehensive kinetic model. The validated model was preliminarily applied to study the effects and mechanisms of the concentrated solar flux nonuniformity and the locally-installed KSM on PTSRR photo-thermal-chemical comprehensive characteristics and performance, taking the methanol flow rate and the catalyst sintering temperature limitation into account. With a preliminary optimization on the concentrated solar flux nonuniformity, the optical efficiency and the solar flux nonuniformity are improved by 6.58% and 30.42% respectively. It is further revealed that these PTSRRs of better concentrated solar flux density nonuniformity also have better thermal-chemical comprehensive characteristics and performance. Novel PTSRRs of the locally-installed KSM have better comprehensive characteristics and performance than corresponding original PTSRRs or even optimized PTSRRs, with a maximum increase in the methanol conversion rate of 6.92%. It thus will operate more safely and more efficiently, by the cost of a little more pump power to overcome corresponding larger flow resistance caused by the locally-installed KSM. From the mechanism, this kind of novel PTSRR of a locally-installed KSM provides a useful option of high potential for improving uniformities of a series of key field variables in the whole photo-thermal-chemical conversion process, and thus improves the comprehensive characteristics and performance of PTSRRs.