EET

Bigger role for world's best industrial insulator

You might call them the super-efficient insulators that few people have ever heard of. That's because nanoporous materials called aerogels have primarily been found in such high-end applications as insulating oil pipelines going deep into the ocean. Made by Aspen Aerogels, Northborough, Mass. (www.aerogel.com), aerogels have been produced by casting lightweight silica solids derived from a gel onto a fibrous batting and then supercritically drying the resulting blanket. Supercritical drying removes liquid in a precisely controlled way, similar to freeze drying.

To cut manufacturing costs and let aerogel work in more industrial applications, the DoE's Industrial Technologies Program (ITP) gave Aspen Aerogels a grant to develop aerogel-based insulation that would work well in industrial-steam components including pipes, valves, and traps. The work resulted in two aerogel-based insulators: Cryogel Z for insulating cold industrial applications (down to -460°F) and Pyrogel XT for hot ones (up to1,200°F).

Cryogel Z targets ambient and sub-ambient piping and equipment, cryogenic storage and transport, industrial gases, and chilled water systems. It has the lowest k-value (at any application temperature) of any cryogenic insulation material. This lets a thin slice of aerogel do the job of traditional insulators that are twice as thick or more. The material comes in a flexible blanket form, with a factory-applied, mylar vapor barrier. Cryogel Z has a coefficient of thermal expansion similar to that of stainless steel, so temperature changes don't move the insulation system much. The insulation is hydrophobic (resistant to liquid water) through the entire matrix of the material, not just on the surface, so it is good at keeping out moisture. Other insulations tend to absorb moisture over time, potentially corroding the substrate. Aspen Aerogels says the material's flexible wrap form eliminates the need for the costly and labor-intensive expansion and contraction joints that characterize traditional rigid insulation systems. According to the company, the insulation costs about as much as other insulation systems once installation costs are figured in. That's because it takes less aerogel to do the job; the material does not break during shipment; it costs less to ship then less-bulky insulation; and there are fewer site storage and logistics involved. Cryogel Z comes in 0.20 and 0.40-in.-thick sheets.

Pyrogel XT is for hot piping and equipment, towers, tanks, high-temperature ducts, and fire protection. It is the most efficient of all industrial insulations, so a piece 50% to 80% thinner than other materials will insulate as well. As with all insulation materials, the R value = thickness of material/k-value in BTU in/hr-sq.ft-°F. Thus, like the k value, the R value depends on temperature, but it's nearly double the insulation value of the best rigid insulation boards currently available. Pyrogel XT also meets all specifications for stress crack corrosion of stainless steel and it too is hydrophobic. Installation is as simple as wrapping Pyrogel XT onto piping and equipment. This process contrasts with that for rigid insulation materials which typically get installed piece-by-piece in sections. Pyrogel XT also comes in 0.20 and 0.40-in.-thick sheets.

According to Aerogel, the insulation has been installed in plants around the world including those of ExxonMobil, Suncor, Valero, and Chevron. ITP estimates that if aerogel insulation was applied to 40% of the 160,000 miles of U.S. industrial steam pipes, industry would see an annual energy cost savings of $117 million by 2025.

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