In an effort to reduce emissions, the use of alternative fuels, such as methane, is being explored to replace diesel. More effective handling of methane can be obtained at either high pressures and/or low temperatures to increase the density and minimize the storage volume. Polymeric composite overwrapped pressure vessels provide a light weight solution for these applications. However since most COPVs have been designed and developed for ambient applications, utilization at cold temperatures requires an understanding of the materials performance at the intended operating conditions. Methodologies developed for cold storage COPVs may be expanded to other structures like pipelines and risers used for polar, off-shore environments.
The arctic conditions in the polar regions create challenges for selection of materials to be used in the fabrication of components used in oil exploration. These challenges are similar to those encountered in the storage and transport of crude oil and natural gas. Technologies have been developed for transoceanic transportation of methane which provides some insight to use in automobiles and trucks. At high pressure, cryo-compressed methane gas has a density close to liquid methane which simplifies the cold storage system. Design of an insulated cryogenic COPV for operation at 144K and 20 MPa, has a broad range of applications. Successful fabrication of a high pressure, light weight, cryogenic COPV can be realized using an aluminum metal liner overwrapped with carbon fiber and an appropriate resin matrix. Aluminum alloys become stronger and have higher ductility at cryogenic temperatures which results in increased cycle life. The resin must be properly selected to be able to transfer the load among the fibers at temperatures well below its glass transition temperature. To meet the design goal of a cryogenic COPV, novel materials and test methods have been developed to verify the performance at cryogenic conditions.
