Selecting the best piping arrangement for scaling-up an annular channel reactor: An experimental and computational fluid dynamics study

Francisca C Moreira; Elvira Bocos; Ana G F Faria; Joana B L Pereira; Cláudio P Fonte; Ricardo J Santos; José Carlos B Lopes; Madalena M Dias; M A Sanromán; M Pazos; Rui A R Boaventura; Vítor J P Vilar

doi:10.1016/j.scitotenv.2019.02.260

Selecting the best piping arrangement for scaling-up an annular channel reactor: An experimental and computational fluid dynamics study

Sci Total Environ. 2019 Jun 1:667:821-832. doi: 10.1016/j.scitotenv.2019.02.260. Epub 2019 Feb 22.

Affiliations

¹ Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: francisca.moreira@fe.up.pt.
² BIOSUV group, Department of Chemical Engineering, University of Vigo, Isaac Newton Building, Campus As Lagoas Marcosende, 36310 Vigo, Spain.
³ Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
⁴ School of Chemical Engineering & Analytical Science, The University of Manchester, The Mill, Sackville Street, Manchester M13 9PL, United Kingdom.
⁵ Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: vilar@fe.up.pt.

PMID: 30852436
DOI: 10.1016/j.scitotenv.2019.02.260

Abstract

This study is focused on the selection of the best piping arrangement for a pilot scale annular channel reactor intended for the remediation of waters and wastewaters. Two annular channel reactors composed of a single UV lamp and distinct piping arrangements were considered: (i) a novel reactor with tangential inlet/outlet pipes - the FluHelik reactor, and (ii) a conventional Jets reactor. These two reactors were manufactured at lab scale and characterized in terms of residence time distribution (RTD), radiant power and ability to degrade aqueous solutions spiked with a model compound - 3-amino-5-methylisoxazole (AMI) - by H₂O₂/UVC and UVC processes. Computational fluid dynamics (CFD) simulations were used to assess the hydrodynamics, RTD and UV radiation intensity distribution of both reactors at pilot scale. In general, experimental results at lab scale revealed quite similar RTDs, radiant powers and AMI degradation rates for both reactors. On the other hand, CFD simulations at pilot scale revealed the generation of a helical motion of fluid around the UVC lamp in the FluHelik reactor, inducing: (i) a longer contact time between fluid particles and UV light, (ii) more intense dynamics of macromixing as a result of larger velocity gradients, turbulent intensities and dispersion of RTD values around the peak, and (iii) a more homogeneous UV radiation distribution. In addition, the design of the FluHelik reactor can favor the implementation of various reactors in series, promoting its application at industrial scale. The FluHelik reactor was chosen for scaling-up. A pre-pilot scale treatment unit containing this reactor was constructed and its feasibility was proven.

Keywords: Annular channel reactor; Computational fluid dynamics; Process intensification; Reactor design; Scaling-up; Water treatment.