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
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
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
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).