Periodic open cellular structures (POCS) for intensification of multiphase reactors: Liquid holdup and two-phase pressure drop

Beitrag in einer Fachzeitschrift


Details zur Publikation

Autorinnen und Autoren: Lämmermann M, Horak G, Schwieger W, Freund H
Zeitschrift: Chemical Engineering and Processing
Verlag: ELSEVIER SCIENCE SA
Jahr der Veröffentlichung: 2018
Band: 126
Seitenbereich: 178-189
ISSN: 0255-2701


Abstract

Structuring concepts for catalytic reactors provide promising options for process intensification on the process unit level [1,2] as they offer a better control on the occurring transport processes, e.g. on the fluid flow, species distribution, pressure drop and heat transfer. Process intensification aims at the realization of processes that are only limited by reaction kinetics, but not anymore on hydrodynamics [3]. For this reason, in multiphase reactors it is desirable to achieve good liquid distribution, advanced heat transport and low pressure drop, just to mention a few transport characteristics. In this regards, the use of periodic open cellular structures (POCS) is a recent and very promising structuring concept, as packings of these structures offer superior and adjustable properties (e.g. low pressure drop, high surface area, good liquid distribution, advanced heat transfer) [4-8].In this contribution, static and dynamic liquid holdup as well as single- and two-phase pressure drop was measured in POCS. These kinds of structures can be used as catalyst support in packed bed reactors, and also as liquid distributor for trickle-bed applications. The POCS investigated in this study were fabricated with different additive manufacturing methods (fused deposition modeling, stereolithography and selective electron beam melting) to study the influence of different materials (ABS, resin, Ti6Al/4V). For the description of the static liquid holdup, a modified Eotvos correlation, which takes the contact angle of the different materials into account, is proposed. Dynamic liquid holdup and two-phase pressure drop was modelled using an extension of the concept of hydrodynamic tortuosity proposed by Inayat et al. [8], and a modification of the relative permeability model introduced by Saez et al. [9]. Furthermore, equations for the geometric characterization of POCS consisting of different unit cell types, namely Diamond, Kelvin and the recently presented DiaKel hybrid cell [5] were derived. The window diameter of the used unit cells as well as the porosity has a strong influence on the liquid holdup and the pressure drop. By taking the contact angle into account the static liquid holdup can be calculated with good precision (errors smaller than 20%). The concept of geometric tortuosity and the relative permeability model also is applicable to predict the (two-) phase pressure drop and the dynamic liquid holdup in stacked packings of POCS segments of different unit cells and materials. Both, pressure drop and liquid holdup can be predicted a priori (i.e., without further fitting) with good precision using the correlations established in this work solely based on geometric properties of the packing.


FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

Freund, Hannsjörg Prof. Dr.
Professur für Katalytische Reaktoren und Prozesstechnik
Littwin, Giulia
Lehrstuhl für Chemische Reaktionstechnik
Lämmermann, Markus
Professur für Katalytische Reaktoren und Prozesstechnik
Schwieger, Wilhelm Prof. Dr.
Professur für Technische Chemie (Reaktionstechnik)


Zusätzliche Organisationseinheit(en)
Exzellenz-Cluster Engineering of Advanced Materials


Forschungsbereiche

D Catalytic Materials
Exzellenz-Cluster Engineering of Advanced Materials


Zitierweisen

APA:
Lämmermann, M., Horak, G., Schwieger, W., & Freund, H. (2018). Periodic open cellular structures (POCS) for intensification of multiphase reactors: Liquid holdup and two-phase pressure drop. Chemical Engineering and Processing, 126, 178-189. https://dx.doi.org/10.1016/j.cep.2018.02.027

MLA:
Lämmermann, Markus, et al. "Periodic open cellular structures (POCS) for intensification of multiphase reactors: Liquid holdup and two-phase pressure drop." Chemical Engineering and Processing 126 (2018): 178-189.

BibTeX: 

Zuletzt aktualisiert 2019-22-07 um 07:30