Better integral insulation for cryo-tanks

High-performance cryo-tank insulation at easier-to-maintain vacuums

Sub-micron polypropylene fibers (under one micron in diameter) made with Melt Film Fibrillation (MFF) technology may produce better integral insulation for cryo-tanks, and probably operate more efficiently than current insulation solutions. Conventional cryo-tank insulation requires a vacuum near 10-4 Torr. This level of vacuum is difficult to maintain, especially for industrial installations such as liquid natural gas and hydrogen fueling stations, in high-pressure installations, and with medical gases. Any outgassing from the insulation material itself may compromise the vacuum and the insulation, allowing for increase in conduction. MFF fibers are made from thermoplastic polymer and do not include binders that can outgas. The MFF fibers sandwiched between the foil reflective layers are sub-micron scale and, they may provide increased coverage and separation of the foils at lower mass versus larger fiber material. MFF fibers are typically made from polypropylene which is virtually transparent to infra-red at the frequencies of concerned for tank insulation. The network of sub-micron MFF fibers also may interferes with the molecular transport process for those molecules that do infiltrate the insulation space. The MFF technology delivers consistent sub-micron fibers at commercial throughput rates, enabling improved economics over traditional sub-micron technology such as electro-spinning and advanced meltblowing. Furthermore, it is expected that equivalent performance to other products should be achievable with less fiber mass, significantly reducing material costs, weight, size, shipping costs, and so forth; or when using equivalent fiber mass, performance in many application areas could dramatically be enhanced.

Benefits Summary:
- Low off-gasing material that is near transparent to IR.
- Uniform separation of the foil layers
- Small pores reduce gas convection
- Technology economics comparable to traditional meltblowing process
- Solvent and binder free manufacturing process

(more on www.yet2.com ref. TP-62733)

Opportunities

• Going international
• Technology transfer
• Business Development

Scientific typology

Current products used in integral tank insulation include glass, melamine-on-glass, mylar films, and film/aerogel composites. These conventional materials put more mass in contact with the two insulating foil layers than expected for MFF fibers. Outgassing and fragility of the conventional materials contribute to convection and loss of insulating properties. MFF technology delivers consistent sub-micron fibers at commercial throughput rates than other sub-micron technology. The sub-micron fibers of MFF provide many more fibers per unit mass and several times greater surface area per unit mass than melt-blown fibers (which typically measure 2–6 microns in size).

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