TY - JOUR
T1 - On the hydrodynamics of membrane assisted fluidized bed reactors using X-ray analysis
AU - Helmi, A.
AU - Wagner, E. C.
AU - Gallucci, F.
AU - Van Sint Annaland, Martin
AU - van Ommen, J. R.
AU - Mudde, R. F.
PY - 2017/12/1
Y1 - 2017/12/1
N2 - The application of membrane assisted fluidized bed reactors for distributed energy production has generated considerable research interest during the past few years. It is widely accepted that, due to better heat and mass transfer characteristics inside fluidized bed reactors, the reactor efficiency can outperform other reactor configurations such as packed bed units. Although many experimental studies have been performed to demonstrate and monitor the long term performance of membrane assisted fluidized bed reactors, the hydrodynamics of membrane-assisted fluidized bed reactors has thus far only been studied in pseudo-2D geometries. In this work the solids concentration inside a real 3D fluidized bed reactor geometry was measured using a fast X-ray analysis technique. Experiments were conducted in absence and presence of two different membrane modules with different configurations and number of membranes (porous Al2O3 tubes) for two types of particles, viz. 400–600 μm polystyrene (Geldart B type) and 80–200 μm Al2O3 (Geldart A/B type). Results from the experiments with Geldart B type particles revealed that the membrane modules (both the membranes and the spacers) can significantly reduce bubble growth along the fluidized bed resulting in a smaller average bubble diameter, expected to improve the bubble-to-emulsion mass transfer, whereas for the experiments with fine Geldart A/B particles, and at a very high extraction values (40% of the inlet flow), a densified layer with high solids concentration was formed near the membrane, which may impose an additional mass transfer resistance for gas components to reach the surface of the membranes (concentration polarization). The results from this study help designing and optimizing the positioning of the membranes and membrane spacers for optimal performance of fluidized bed membrane reactors.
AB - The application of membrane assisted fluidized bed reactors for distributed energy production has generated considerable research interest during the past few years. It is widely accepted that, due to better heat and mass transfer characteristics inside fluidized bed reactors, the reactor efficiency can outperform other reactor configurations such as packed bed units. Although many experimental studies have been performed to demonstrate and monitor the long term performance of membrane assisted fluidized bed reactors, the hydrodynamics of membrane-assisted fluidized bed reactors has thus far only been studied in pseudo-2D geometries. In this work the solids concentration inside a real 3D fluidized bed reactor geometry was measured using a fast X-ray analysis technique. Experiments were conducted in absence and presence of two different membrane modules with different configurations and number of membranes (porous Al2O3 tubes) for two types of particles, viz. 400–600 μm polystyrene (Geldart B type) and 80–200 μm Al2O3 (Geldart A/B type). Results from the experiments with Geldart B type particles revealed that the membrane modules (both the membranes and the spacers) can significantly reduce bubble growth along the fluidized bed resulting in a smaller average bubble diameter, expected to improve the bubble-to-emulsion mass transfer, whereas for the experiments with fine Geldart A/B particles, and at a very high extraction values (40% of the inlet flow), a densified layer with high solids concentration was formed near the membrane, which may impose an additional mass transfer resistance for gas components to reach the surface of the membranes (concentration polarization). The results from this study help designing and optimizing the positioning of the membranes and membrane spacers for optimal performance of fluidized bed membrane reactors.
KW - Fluidized bed
KW - Solids concentration
KW - Vertical membranes
KW - X-ray
UR - http://www.scopus.com/inward/record.url?scp=85019976626&partnerID=8YFLogxK
UR - http://resolver.tudelft.nl/uuid:0c6f8771-0bf8-4ac5-bef8-103544bc5d17
U2 - 10.1016/j.cep.2017.05.006
DO - 10.1016/j.cep.2017.05.006
M3 - Article
AN - SCOPUS:85019976626
SN - 0255-2701
VL - 122
SP - 508
EP - 522
JO - Chemical Engineering and Processing: process intensification
JF - Chemical Engineering and Processing: process intensification
ER -