Assisted Fluidized Bed Reactors

The idea to limit polarization and fouling during tangential filtration of biological fluid by fluidizing small inert particles inside a tubular ceramic membrane had been presented at the end of the 1980s [25]. More recently, based on advances in the development of more stable membranes with increased permeance, the possibilities for integrating membranes into gas catalytic reactors to achieve a major increase in 

Several reviews and even special issues of catalysis related journals illustrate the significant progress in the field of inorganic membrane reactors within the last two decades [7]. 

The fraction of CH4 feed is fed through the bottom section in such a way that the permeating O2 is able to generate CPO (catalytic partial oxidation) equilibrium conditions in the bottom section, the temperature of which is in turn favorable for the permselective O2 transport. The steam is also added to avoid coke formation in the bottom section. The top section is then fed with the remaining CH 4 and steam feed so that overall autothermal process is achieved when both sections are considered together. The endothermic heat demand of the top section is thus catered by the equilibrium mixture corning from the bottom section and the side feed of additional CH4 and steam. 

---

Patil, C.S., van Sint Annaland, M., and Kuipers, J.A.M. Design of a novel autothermal membrane-assisted fluidized-bed reactor for the production of ultrapure hydrogen from methane. Industrial Engineering Chemistry Research, 2005, 44 (25), 9502. 

The proposed novel membrane-assisted fluidized bed reactor (MAFBR) consists of a partial oxidation bottom section and a steam reforming of methane/water-gas shift SRM/WGS top section (Figure 4.8). Because of the large difference in operating temperatures of the permselective H2 membranes (below 700 °C) and permselective O2 membranes (above 900 °C), two sections operate at these respective temperatures. 

Deshmukh SARK, Heinrich S, Mori L, van Sint Annaland M, and Kuipers JAM. Membrane assisted fluidized bed reactors Potentials and hurdles. Chem. Eng. Sci. 2007 62 416 36. 

Patil, C.S., Annaland, M.V. and Kuipers, J. A.M., 2005. Design of a Novel Autothermal Membrane-Assisted Fluidized-Bed Reactor for the Production of Ultrapure Hydrogen from Methane. Industrial Engineering Chemistry Research, 44(25) 9502-9512. 

The extent of mass and heat transfer limitations in packed bed membrane reactors have forced researchers to investigate other solutions to circumvent those limitations. In this respect, membrane assisted fluidized bed reactors have... 

A typical ID two-phase model for a membrane assisted fluidized bed reactor can be used for the simulation of the fluidized bed membrane reactor for hydrogen production via methane reforming. A schematic representation of the gas flows between the compartments of the bubble and emulsion phases is depicted in Figure 10.6. The model main assumptions are ... 

In this approach, the smaller scale models are used to determine the closure equations to be used in larger scale models. The final aim is to obtain better and more general closure equations for heat, momentum and mass transfer that can be applied in phenomenological models and account for the presence of and permeation of gas through membranes in membrane assisted fluidized bed reactors instead of the previous described (empirical) closure equations obtained for reactors without membranes. 

S. A. R. K. Deshmukh, J. A. Laverman, A. H. G. Cents, M. Van Sint Annaland and J. A. M. Kuipers, Development of a membrane assisted fluidized bed reactor. 1. Gas phase back-mixing and bubble-to-emulsion phase mass transfer using tracer injection and ultrasound experiments, Ind. Eng. Chem. Res., 2005, 44, 5955 5965. 

Patil, C. S., van Sint Annaland, M., Kuipers, J. A. M. (2006). Experimental study of a membrane assisted fluidized bed reactor for H2 production by steam reforming of CH4. Chemical Engineering Research and Design, 84, 399—404. 

Figure 4.4 Process flow diagram of an experimental pseudo-2D membrane-assisted fluidized bed reactor for optical measurements. Reprinted from De Jong et al. (2011) with permission from Elsevier. 

Deshmukh SARK, Laverman JA, Cents AHG, van Sint Annaland M, Knipers JAM Development of a membrane-assisted fluidized bed reactor. 1. Gas phase back-mixing and... 

Paul CS, Van Sint Annaland M, Kuipers JAM Design of a novel auto-thermal membrane assisted fluidized bed reactor for the production of ultra-pure hydrogen firom methane, Ind Eng Chem Res 44 9502—9512, 2005. 

A typical fluidized membrane reactor (or membrane-assisted fluidized bed reactor - MAFBR) consists in a bundle of permselective membranes immersed in a catalytic bed operated in a bubbling or turbulent fluidization regime. The use of fluidized bed membrane reactors not only makes possible the reduction of bed-to-wall mass transfer limitations, but also allows operating the reactor under virtually isothermal conditions (due to the movement of catalyst). This possibility can be used for operating the autothermal reforming of hydrocarbons inside the membrane reactor. In fact, as indicated by Tiemersma et al. [13], the autothermal reforming of methane in a packed bed membrane reactor is quite... 

Different research groups applied membrane-assisted fluidized bed reactors for different reaction systems (mostly involving hydrogen) as indicated in Table 33.3. 

A typical Pd-based membrane-assisted fluidized bed reactor has been proposed by Adris et al. and is shown in Figure 33.6. 

J.A.M. (2007) Membrane assisted fluidized bed reactors potentials and hurdles. 

Fluidized bed membrane reactors, also called membrane assisted fluidized bed reactors, are a special type of reactor in which the permeable membranes are integrated inside a fluidized reaction bed to intensify the reaction process. Such integration not only provides the advantages of both the fluidized bed and the membrane reactor, but also accomplishes a synergistic effect. The main advantages of FBMRs include [1] ... 

Dehkordi, A.M., Savari, C. and Ghasemi, M. (2011) Steam reforming of methane in a tapered membrane-assisted fluidized bed reactor Modeling and simulation. International Journal of Hydrogen Energy, 36, 490-504. 

---