Photo courtesy of Cabot Corp.
Aerogel, a lightweight micro-porous material, has been around since the late 1920s, yet production drawbacks kept it from being commercially successful.
Generally recognized as having the highest insulation value of any known material, aerogel withstands extreme environments, decreases installation costs, lowers hazardous emissions and reduces energy losses. But it was not until recently that the material began to reach its commercial potential.
The original process that produced aerogel required a supercritical drying method. Failed efforts to research and improve the production process led to discontinued production until the 1990s, when researchers discovered safer, more efficient manufacturing methods. Today, there are two main approaches to making aerogel. First is a surface modification technique - a patented approach owned by materials company Cabot Corp., Oak Brook, Ill. - that allows for subcritical liquid evaporation without significant gel shrinkage. The other method, developed by insulation manufacturer Aspen Aerogels in Northborough, Mass., involves casting silica gel onto a fibrous batting and then supercritically drying the resulting blanket.
High manufacturing costs had relegated aerogels mainly to high-end industrial insulation applications in the oil, gas and chemicals industries. In order for aerogels to work in the high- and low-temperature environments required in industrial steam, fuel transport and cold insulation applications, new formulations of the standard aerogel material had to be developed.
In 2006, the U.S. Department of Energy's Industrial Technologies Program awarded Aspen Aerogels a research and development grant to come up with an aerogel-based thermal insulation system for industrial steam-distribution systems, including pipes, valves, traps and other line components. The company developed its Cryogel and Pyrogel aerogel systems for insulation applications at cold temperatures down to -46°F (-43°C) and hot temps up to 1,200°F (648.88°C). Low temperature applications include petrochemical processing, liquefied natural gas, chilled water and cryogenic air separation, while high temperature applications include refineries, gas processing and power plants.
Aerogel-based pipe insulation performs a similar function to traditional steam-pipe insulation systems, which employ mineral wool, fiberglass, calcium silicate, perlite and various foams. However, as a flexible-blanket material with intrinsic hydrophobicity, aerogel is not susceptible to the embrittlement or logging that deteriorates traditional materials. Additionally, aerogel significantly reduces the amount of material needed to perform the same thermal function, and can be doped to provide durable water repellency, mitigating one of the primary modes by which insulation degrades and energy is subsequently lost. The process also helps protect pipelines from corrosion.
Aerogel insulation has been successfully installed and used in plants around the world, including ExxonMobil, Suncor, Valero and Chevron. The DOE's Industrial Technologies Program estimates that if aerogel insulation was applied to 40 percent of the 160,000 miles of U.S. industrial steam pipes, annual energy savings of 16 trillion BTUs and $117 million in energy cost savings could be achieved by 2025.
While much of the market focus for aerogel has been on high end industrial applications, the product is beginning to reach a broader potential. Other emerging applications include:
- Matting coatings for wear, corrosion and
thermal resistance in industrial applications.
- Industrial and commercial insulation strips for
heat and noise insulation.
- Window insulating material for furnaces, kilns,
spacecraft and commercial and residential buildings.
- Shock-absorbing material.
- Structural composite insulation panels for commercial buildings.
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