Hydrogen Separation - Dense Metal Membranes

Question 1

Summarise Purification Methods

Answer 1

Pressure Swing Adsorption
Microporous Membranes
Paladium based Membranes

Slide 8/5

Paladium is a special case of membranes

Question 2

Summarise Membrane Materials

Answer 2

Inorganic
- Ceramic
- Metallic (Dense Metal Membranes)
Organic
- Biological
- Polymeric
Hybrid

Question 3

What Pore Sizes are there for Membranes?

Answer 3

1) Microporous (<2nm) - Knudsen
2) Meso-porous (between)
3) Macro-porous (>50nm) - Viscous Flow

See 8/9

Question 4

List Important Operation Parameters of Membranes

Answer 4

Diffusivability
Solubility
Temperature
Area
Pressure Difference
(Membrane Thickness - decreases flux)

Slide 8/14

Question 5

3 Criteria for Metallic Membrane Selection

Answer 5

1) Avoid stable hydride forming alloys
2) Open crystal structure preferred (bcc > fcc)
3) Avoid oxophylic - easily form oxide

Slde 8/15

NOT Stable - OPEN Crystal - NOT Oxygen-loving

Question 6

List candidate Metals (etc) for Hydrogen separation

Answer 6

Pure metal
Coated metal

Binary alloy
Complex alloy
Amorphous alloy (group 4/5 metals)

See 8/16

Amorphous Alloys –> Security Guards (Group4)

Question 7

Membrane Fabrication

Answer 7

Rolling
Solution Plating
Vapour Deposition

See 8/20

One solid, one liquid, one gas?! (Rolling a plate full of shit)