Micromixing efficiency of a novel helical tube reactor: CFD prediction and experimental characterization. (22nd November 2016)

• Record Type: Journal Article
• Authors: Luo, Jiang-Zhou; Luo, Yong; Chu, Guang-Wen; Arowo, Moses; Xiang, Yang; Sun, Bao-Chang; Chen, Jian-Feng
• Is Part Of: Chemical engineering science. Volume 155(2016)
• Page Start: 386
• Page End: 396
• Publication Date: 2016-11-22
• Subjects: Helical tube reactor -- Pre-mixer -- Micromixing efficiency -- Computational fluid dynamics; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2016.08.010
• Languages: English
• ISSNs: 0009-2509

Abstract

Abstract: A novel helical tube reactor (HTR) consisting of a pre-mixer and a helical tube was designed for mixing and reaction process intensification. The pre-mixer was used to adjust and change the premixing behavior between the involved reactants, which eventually determines the environment for micromixing. Two types of pre-mixers, co-current flow pre-mixer (CCM) and cross-flow pre-mixer (CRM), were employed and their mixing performance was studied by computational fluid dynamics (CFD) simulations. Results revealed that the CRM has better mixing performance than the CCM, suggesting that the predicted micromixing efficiency of the HTR consisting of the CRM (CRM-HTR) may be better than that comprising the CCM (CCM-HTR). Furthermore, the iodide–iodate reaction system was used separately to characterize the micromixing efficiency of the HTR comprising the different types of pre-mixers, and the results are in agreement with those of CFD which predicted better micromixing performance in the CRM-HTR than the CCM-HTR. Additionally, the effects of feed position and initial dispersion size of acid solution, volumetric flow ratio, and viscosity on micromixing efficiency of the CRM-HTR were investigated. A comparison between the CRM-HTR and a straight tube reactor (CRM-TR) with a length equivalent to that of the CRM-HTR revealed that CRM-HTR has better micromixing efficiency. Moreover, the effects of curvature ratio and number of turns on micromixing efficiency of the CRM-HTR were also conducted. The results demonstrated that the curvature ratio had an important influence on the micromixing. This work shows that the novel CRM-HTR has great potential for chemical reaction process intensification. Highlights: A novel helical tube reactor (HTR) was composed of a pre-mixer and a helical tube. Premixing behavior in two types of pre-mixers was studied by CFD method. The consistency of CFD prediction and experimental characterization was discussed. Both geometric parameters of HTR and operating parameters affect the micromixing.