Arratibel, Alba (PhD)

Pd-Ag “pore-filled” membranes for hydrogen separation

A. Arratibel, F. Gallucci, M. van Sint Annaland

Room: STW 0.34, E-mail: A.Arratibel.Plazaola@tue.nl

Introduction

Membrane reactors are reactors integrating catalytic reactions and separation through membranes in a single unit. This combination of process steps results in a high degree of process integration/intensification, with accompanying benefits in terms of increased process or energy efficiencies and reduced reactor or catalyst volume. Palladium membranes have been used in membrane reactors (generally reforming and water gas shift reactions for hydrogen production) due to their remarkable permeability and exclusive perm-selectivity of hydrogen. In order to attain high hydrogen flux and minimize the material costs, researchers have been motivated to fabricate thin palladium membranes. The surface of thin Pd based membrane is prone to become contaminated and mechanically damaged; the damage is even more serious when it is used as part of fluidized bed membrane reactors where the collision with the catalyst particles can erode and destroy thin Pd membranes. Improved mechanical stability and better adhesion of the palladium membrane can be expected by filling nanosized pores of a ceramic support with palladium particles.

Novel “Pore-filled” (PF) Pd membranes have been developed by the electroless plating technique. Four steps are involved in the preparation of the “Pore-filled” membranes:

(1) Coating of  the surface of α-Al2O3 support tube with a  nanoporous ceramic layer

(2) Seeding; nanoparticles of Pd are deposited inside the porous ceramic

(3) Coating with a nanoporous protecting ceramic layer

(4) Electroless plating; forcing to pass a Pd plating solution through the pores.

This “Pore-filled” membrane configuration provides advantages of membrane handling since palladium layer is not exposed directly on the top surface; the amount of Pd used is a fraction of the conventional Pd membranes and are stronger against hydrogen embrittlement. In this work, the preparation and characterization of Pd-Ag pore filled membranes will be for the first time reported.

Objective

  • Development of pore-fill membrane with high hydrogen permeation and selectivity.
  • Physical and chemical characterization of pore-filling membranes.
  • Characterization of permeation properties of pore-filling membranes at single gas test (hydrogen and nitrogen) and under reaction (methane steam reforming and     auto-thermal reaction) in a fluidized bed.
  • Design of the novel proposed reactor and experimental evaluation (model           validation).