High Performance Fluoroelastomer Nanocomposite Seals For Geothermal Submersible Pumps

The Electrical Submersible Pumps (ESPs) used in geothermal energy production are subjected to harsh downhole environments that include hot brine (e.g. calcium chloride), corrosive hydrogen sulfide/carbon dioxide, silica, and entrained sand, all at temperatures in the range of 300 to 450 °F. The fluoroelastomeric materials used as seals in these applications degrade in a relatively short period of time in these environments, which can lead to equipment failure. Attempts to improve the modulus and hardness have been accompanied by a reduction in elongation. This project will develop novel functionalized nanoscale additives that are designed to beneficially alter the stress-strain behavior of fluoroelastomers. Phase I synthesized surface functionalized nanoparticles and fabricated fluoroelastomer sheets and O-rings containing these nanoscale additives. An 82% improvement in modulus and a 7 point increase in Shore A hardness was observed, without decreasing the elongation at break. Phase II will (1) optimize the structure/size of the nanoscale additives; (2) determine structure/property correlation and interfacial mechanisms of the nanoscale additive and the fluoroelastomer; and (3) perform an objective comparison of the nanocomposite fluoroelastomers with that of commercially-used state of the art fluoroelastomer materials. Those nanoscale additives that show dramatic improvement will be utilized in fabricating prototype seals and supplied to potential customers for evaluation. Commercial Applications and other Benefits as described by the awardee: The development of novel nanoscale additives for sealing applications offers a potentially new set of performance characteristics for fluoroelastomers. In addition to oil, gas, and geothermal operations, processes in pharmaceuticals, medical devices, and microelectronics could benefit from seals that offer better barrier and mechanical performance than currently available materials.