Long-Term Stability of Thin-Film Pd-Based Supported Membranes

Abstract

Membrane reactors have demonstrated a large potential for the production of hydrogen via reforming of different feedstocks in comparison with other reactor types. However, the long-term performance and stability of the applied membranes are extremely important for the possible industrial exploitation of these reactors. This study investigates the long-term stability of thin-film Pd-Ag membranes supported on porous Al2O3 supports. The stability of five similarly prepared membranes have been investigated for 2650 h, up to 600 °C and in fluidized bed conditions. Results show the importance and the contribution of the sealing of the membranes at temperatures up to 500 °C. At higher temperatures the membranes surface deformation results in pinhole formation and a consequent decrease in selectivity. Stable operation of the membranes in a fluidized bed is observed up to 450 °C, however, at higher temperatures the scouring action of the particles under fluidization causes significant deformation of the palladium surface resulting in a decreased selectivity.

Techno-Economic Assessment in a Fluidized Bed Membrane Reactor for Small-Scale H2 Production: Effect of Membrane Support Thickness

“…As anticipated, the effect of varied sweep flow also plays an important role in maximum-achieved HRF according to the two studies [18,22,27]. The calculations performed in this work at varying sweep flow rates are reported in Figure 6, using the two thickness’ based on mechanical stability and sealing issues equal to 0.5 and 2 mm [31] for 316 L and α-Al 2 O 3 , respectively. On the x-axis, a sweep flow to H 2 permeated ratio is used because it allows implementation of the results in different models.…”

“…The three reactions that are happening in the bottom region (SMR, WGS, and OX) are modelled by the kinetic laws from Trimm and Lam, and Numaguchi and Kikuchi [38,39]. The reactor is designed as isothermal, which corresponds to preliminary tests running on the prototype of this reactor [31]. The performance is represented by the hydrogen recovery factor (HRF).…”

“…Typically, thicker ceramic supports (up to 3.5 mm) are the most common support used in Pd membranes [21,30,31], being cheaper than the metallic ones and ensuring high selectivity.…”

Study of Static and Dynamic Behavior of a Membrane Reactor for Hydrogen Production

“…There has been active research in recent years in the use of catalytic membrane reactors for cracking ammonia to produce pure hydrogen [7][8][9][10][11][12][13][14][15]. de Nooijer et al [10], for instance, studied the thermal stability and performance of Pd-Ag films used in membrane reactors for hydrogen production via the reforming of different feedstocks.…”

“…There has been active research in recent years in the use of catalytic membrane reactors for cracking ammonia to produce pure hydrogen [7][8][9][10][11][12][13][14][15]. de Nooijer et al [10], for instance, studied the thermal stability and performance of Pd-Ag films used in membrane reactors for hydrogen production via the reforming of different feedstocks. Petriev et al [11] carried out experimental modification of the surface of Pd-Ag films and showed that hydrogen permeability rate depends not only on the surface area but also on the structure of the membrane modifying layer.…”