Micromixing Performance of Microchannel Reactors after Sizing-Up and Their Application in the Preparation of Ni–Co–S Composites

Abstract

To investigate the sizing-up effects of microchannel reactors, a 0.6 mm i.d. microchannel reactor along with a 2 mm i.d. tube reactor, a 3 mm i.d. tube reactor, and a 4 mm i.d. tube reactor was assembled, and their micromixing performance was evaluated experimentally with the I–/IO3– parallel competitive reaction system at different Re. The results showed that at low Re, the segregation index XS (used to characterize the micromixing efficiency) of all tube reactors decreased (indicating strengthened micromixing efficiency) noticeably with increasing Re, and the XS of tube reactors with a bigger inner diameter was much larger than that of the reactors with a smaller inner diameter at the same Re. When Re was bigger than 5584, the XS of all tube reactors with different inner diameters would become almost the same as ∼3.4 × 10–4 and remained unchanged with further increasing Re, suggesting a negligible sizing-up effect of the microchannel reactor on the micromixing performance at sufficiently high Re. In addition, Ni–Co–S composites were prepared in the four different tube reactors at the optimal Re of 6700, and the physical and electrochemical properties of the prepared Ni–Co–S composites were almost the same, further demonstrating the negligible sizing-up effects of the microchannel reactor at high Re.