Description of capability
The Karnik Group at MIT has developed membranes that consist of nano-structured palladium with potential for reduced use of precious metal, operation at higher temperatures, and more resistance to radiation or tritium decay.
Motivated by the need to develop membranes that can withstand high temperatures and are less susceptible to helium entrapment or radiation damage, the Karnik Group has developed a membrane that consists of discrete nano-structures (“plugs”) of metal embedded in pores of another material. The rationale is that the isolated structures would be thermodynamically stable (in contrast to metal films) and have interfaces that defects could migrate to. The specific membranes they have fabricated are palladium plugs in silica pores. The membranes show decent selectivity and preliminary studies show that they can tolerate high temperatures that would tend to de-wet metal films.
Key people
- Rohit Karnik
- (Lohyun Kim, the grad student, is joining Intel. He may be interested in a startup, but only after getting a green card.)
Technology Readiness Level (1-9)
TRL 4 – Membrane demonstrated to function in lab. These are centimeter-scale.
Needs that this could potentially address
- Fuel recycling and tritium recovery for fusion power
- High-temperature separation of hydrogen from dehydrogenation of liquid organic hydrogen carriers (LOHCs), especially MCH-Toluene (pursued by companies by Chiyoda)
- Cracking of hydrocarbons at high temperatures (e.g., H2/N2 separation from cracking of ammonia (NH3 ⇒ N2 + H2))
- More conventional metal membrane applications, e.g.:
- Petrochemical reforming (e.g. (CH4 ⇌ H2 and CO)
- Water gas shift reaction (CO + H2O ⇌ CO2 + H2)
- Fischer–Tropsch process for synthetic fuels (CO and H2 ⇌ hydrocarbons)
Membrane separation processes have been proposed for several gas separations, such as natural gas upgrading [4], pre- and post-combustion carbon capture [5] and H2 purification [6,7].
Tech specs
- Hydrogen permeance: 10E-7 to 10E-6 mol/m2-Pa-s. This is similar to conventional Pd membranes.
- Hydrogen/helium (and other gases) selectivity: >100 (if you don’t have too many leaks or defective plugs). But if you need perfect selectivity, not sure this is the right fit. There will be gaps and defects somewhere.
- Operating temperature range: 200 ºC to 800 ºC and likely much higher. This is an advantage over conventional Pd membranes.
- Opportunity for lower cost: Pd layer is ~1 µm, compared with existing membranes with ~20 µm Pd layers. Membrane cost scales with the Pd thickness. The cost of the support is unknown, however.
- In principle, defects have the ability to migrate to a surface more easily, so these should be more robust to irradiation.
Estimated time & cost to commercialize
3-5 years, $5-10M
Outstanding risks
- Long-term performance in real environments remains to be verified; may necessitate changes in membrane design or material
- Membrane cost has some uncertainty, especially for the porous substrate
- Manufacturability (or supply chain) of porous substrates
- Pd membranes only work at elevated temperatures, which limits the range of useful applications
Open questions
- What will be the membrane cost (esp. the support)?
- What are the applications where is this a game-changer?
- What is the best commercialization pathway for this?
- What role for David / Proto Ventures do we see?
References
- Lohyun Kim, Design and Modeling of Nanostructured Palladium-Based Hydrogen-Selective Membranes. Massachusetts Institute of Technology (2024).
- Email communication from Rohit Karnik
- 2024-05-29 Rohit Karnik - Palladium Membranes
- 2024-07-01 Rohit Karnik
- See : High-Temperature Gas Separation Equipment Provider for the Hydrogen Industry