This document summarizes a fluidized bed membrane reactor for pure hydrogen generation. Key points: - The reactor uses horizontal membranes in a fluidized bed to separate hydrogen from the reaction while keeping the H2/CO ratio optimal. - Experimental studies on steam methane reforming and autothermal reforming showed up to 99.995% hydrogen purity and a H2/CH4 yield of 2.07. - Operating parameters like pressure, membrane area, and feed rates were investigated and found to influence reactor performance.

1. FLUIDIZED BED MEMBRANE
REACTOR
Presented by
Vinesh S. Bagade
class-BE Roll-01

2. Content
1. Introduction-
• Definition
• Types of membrane reactor
• Fluidized bed membrane reactor
• Experimental set up
2.Pure hydrogen generation in fluidized bed membrane reactor
• Introduction
• Experimental studies
• Result and analysis
• Conclusion
• Advantages
• Disadvantages
• Referencess

3. Introduction
• A membrane reactor is a device for simultaneously performing a reaction
• The membrane not only plays the role of a separator, but also takes place
in the reaction itself.
• A membrane-based separation in the same physical device
• Membrane can be defined essentially as a barrier which separates two
phases and restricted transport various chemicals in a selected manner

4. Types of membrane reactor
 Zeolite membrane reactor
 Fluidized bed membrane reactor
 Perovskite membrane reactors
 Hollow fiber membrane reactors
 Catalytic membrane reactors

5. Fluidized bed membrane reactor
 Negligible pressure drop
 no internal mass and heat transfer
 Isothermal operation.
 Flexibility in membrane and heat transfer surface area and arrangement of
the membrane bundles.
 Improved fluidization behavior
 Reduced average bubble size due to enhanced bubble breakage,
resulting in improved bubble to emulsion mass transfer.

6. Experimental set up
 Partial oxidation of methanol
 horizontal membranes inserted in the fluidized bed
 it keeps the H2/CO ratio to an optimal value

7. “
”
Pure hydrogen generation
in fluidized bed membrane
reactor
 Introduction
• Hydrogen is currently an important commodity in several industrial
processes
• proton exchange membrane (PEM) fuel
• hydrogen as a milestone to control global warming has grown
• Hydrogen may be produced by steam reforming of fossil fuels, gasification
of coal/biomass, water electrolysis and high-temperature steam electrolysis

8. Experimental studies
 Operation modes
1. SMR with external heating-
• Methane steam reforming (R1): -
CH4+H2O↔CO+3H2 (Ho298=206.2kJmol−1)
• Water--gas shift (R2):-
CO+H2O↔CO2+H2 (H0298=−41.2kJmol−1)
• Methane overall steam reforming (R3):
CH4+2H2O↔CO2+4H2 (H0298=165kJmol−1)
2.ATR with addition of air or water-
• Methane combustion (R4):-
CH4+2O2 ↔CO2+2H2O (H0298=−802.7kJmol−1)
• Hydrogen combustion (R5):-
H2+ 1/2O2 ↔H2O (H0298=−242kJmol−1).

9. Experimental set up

10. Membranes for hydrogen removal
 Transport of H2 molecules to the surface of the metallic membrane
 Reversible chemisorption of H2 molecules on the metal surface
 Reversible dissolution of atomic hydrogen at the membrane surface
 Diffusion of atomic hydrogen through the metal lattice
 Reassociation of atomic hydrogen at the surface of the downstream metal surface
 Desorption of molecular hydrogen from the metal surface
 H2 transport away from the outer surface of the membrane

11. Results
 Overall reactor performance:-
Components Mole fractions
Methane 0.955
Ethane 0.029
Nitrogen 0.007
Propane 0.005
Butane 0.001
Iso-butane 0.0005
Carbon dioxide 0.002
N-butane 0.0001
an overall carbon balance, as indicated by
𝑥𝐶𝐻4 =
,
𝑦𝑐𝑜2 + 𝑦𝑐𝑜
(𝑦𝑐𝑜2 + 𝑦𝑐𝑜 + 𝑦𝑐ℎ4)

12. Influence of key operating parameters
 Heat effects
 Thermodynamic effect of reactor pressure
 Membrane isothermality
 Effect of membrane area
 Effect of pressure driving force
 Effect of air input (SMR vs ATR)
 Effect of air split
 Gas backmixing
 Effect of feed rates

13. Conclusion
The performance of a novel fluidized-bed reactor containing internal vertical
membrane panels was tested under steam methane reforming (SMR) and
autothermal reforming (ATR) conditions, with and without active membranes.
Some reverse reaction was observed in the reactor free board,thus reducing
overall methane conversion
Hydrogen permeate purities up to 99.995% and H2/CH4 yield of 2.07 were
achieved with using only half of the full complement of membrane panels
under SMR condition
The effects of reactor pressure, hydrogen permeate pressure, air top/bottom
split, feed flowrate and membrane load were all investigated.

14. Advantages
 Negligible pressure drop; no internal mass and heat transfer
 small particle sizes that can be employed.
 Isothermal operation.
 Flexibility in membrane and heat transfer surface area and arrangement of
the membrane
 bundles.
 Improved fluidization behavior

15. Disadvantages
 Difficulties in reactor construction and membrane sealing at the wall.
 Erosion of reactor internals and catalyst attrition

16. References
 Chen, Z., Grace, J.R., Lim, C.J., Li, A., 2007. Experimental studies of pure
hydrogen production in a commercialized fluidized-bed membrane reactor
with SMR and ATR catalysts. International Journal of Hydrogen Energy 32 (13),
2359--2366.
 M.E.E. Abashar, S.S.E.H. Elnashaie, Feeding of oxygen along the height of a
circulating fast fluidized bed membrane reactor for efficient production of
hydrogen, Chem. Eng. Res.Des., 85, 1529-1538 (2007).
 Deshmukh, S.A.R.K., Van Sint Annaland, M., Kuipers, J.A.M., 2005c. Heat transfer
in a membrane assisted fluidised bed with immersed horizontal tubes. Int. J.
Chem. React. Eng., 3 A1
 Carlucci, F., Van Sint Annaland M., Kuipers J. A. M., 2008a. Autothermal
Reforming of Methane with Integrated CO2 Capture in a Novel Fluidized Bed
Membrane Reactor. Part 1: Experimental Demonstration. Topics in Catalysis
51133-145
 Adris, A.M., Lim, C.J., Grace, J.R., “The fluidized bed membrane reactor system:
A pilot scale experimental study”, Chem. Eng. Sci., 49, 5833-5843 (1994).
 Boyd, T., Grace, J.R., Lim, C.J., Adris, A.M, “H2 from an internally circulating
fluidized bed membrane reactor”, Int. J. Chem. Reactor Eng., 3. A58, 2005.
 Prasad, P., Elnashaie, S.S.E.H., “Novel circulating fluidized-bed membrane
reformer using carbon dioxide sequestration”, Ind. Eng. Chem. Res., Vol. 43, 494-
501 (2004).