High Pressure Composite Vessel With Integrated Optical Fiber Sensors: Monitoring of Manufacturing Process and Operation

The main purpose of the work was development of high-pressure composite vessel for hydrogen storage (type IV, CFRC) with an integrated Structural Health Monitoring (SHM) system, based on optical fiber sensors. It has been assumed that this NDE system should provide for continuous and reliable monitoring of the structure during its long operation and enable estimation of degradation degree of the composite vessel load-carrying layer, and by that determination of its safe operation period. Showing suitability of the system for control of the vessels manufacturing technology and fulfilling the requirements of vessel certification standards has been also considered essential. It has been expected, that reaching the work goals required application of measurement methods based at fibre optic sensors with particular consideration for the Fibre Bragg Gratings (FBG). These transducers allowed for integration with the monitored object and were embedded in the composite material structure without influencing its mechanical properties. The research object were prototype vessels for Hydrogen storage in automotive applications, with nominal working pressures up to 700 bars. FBG sensors were integrated with COPV during manufacturing process (winding by robot). It allowed for controlling of each manufacturing steps (winding each layer, curing, hydraulic test) and further use during vessel normal operation. Additional investigations were dedicated to evaluation of SHM strategy, which allows for detection of damages in the vessel structure from manufacturing process through the whole lifespan. The proposed SHM solution was validated during pressure cycle test, which were performed according to the current regulations (EC 406/2010).

Steel-Concrete Composite Vessel for Stationary High-Pressure Hydrogen Storage

A novel Steel Concrete Composite Vessel (SCCV) was designed and engineered for stationary high-pressure gaseous hydrogen storage applications. SCCV comprises four major innovations: (1) flexible modular design for storage stations for scalability to meet different storage pressure and capacity needs, flexibility for cost optimization, and system reliability and safety, (2) composite storage vessel design and construction with an inner steel vessel encased in a pre-stressed and reinforced outer concrete shellshell, (3) layered steel vessel wall and vent holes to address the hydrogen embrittlement (HE) problem by design, and (4) integrated sensor system to monitor the structural integrity and operation status of the storage system. Together, these innovations form an integrated approach to make the SCCV cost competitive and inherently safe for stationary high-pressure hydrogen storage services. A demonstration SCCV has been designed and fabricated to demonstrate its technical feasibility. Capable of storing approximately 89 kg of gaseous hydrogen at 6250 psi (430 bar), the demonstration vessel was designed to include all major features of SCCV design and fabricated with today’s manufacturing technologies and code/standard requirements. Two crucial tests have been performed on this demonstration vessel. A hydro-test was successfully carried out to 8950 psi per ASME VIII-2 requirements. The cyclic hydrogen pressure test between 2000 psi and 6000 psi is currently being performed to validate its use for high-pressure hydrogen storage. Multiple sensors, such as pressure sensors and strain gages, were incorporated in the demonstration SCCV to collect information to validate the design and operation of SCCV. Key design parameters and test data on its performance are summarized in this paper.