Validation of Selected Optical Methods for Assessing Polyethylene (PE) Liners Used in High Pressure Vessels for Hydrogen Storage

Paweł Gąsior,Aleksander Błachut,Amelie Baron,Jerzy Kaleta,Neha Yadav,Marcin Ozga,Karol Wachtarczyk

doi:10.3390/app11125667

Abstract

A polyethylene (PE) liner is the basic element in high-pressure type 4 composite vessels designed for hydrogen or compressed natural gas (CNG) storage systems. Liner defects may result in the elimination of the whole vessel from use, which is very expensive, both at the manufacturing and exploitation stage. The goal is, therefore, the development of efficient non-destructive testing (NDT) methods to test a liner immediately after its manufacturing, before applying a composite reinforcement. It should be noted that the current regulations, codes and standards (RC&S) do not specify liner testing methods after manufacturing. It was considered especially important to find a way of locating and assessing the size of air bubbles and inclusions, and the field of deformations in liner walls. It was also expected that these methods would be easily applicable to mass-produced liners. The paper proposes the use of three optical methods, namely, visual inspection, digital image correlation (DIC), and optical fiber sensing based on Bragg gratings (FBG). Deformation measurements are validated with finite element analysis (FEA). The tested object was a prototype of a hydrogen liner for high-pressure storage (700 bar). The mentioned optical methods were used to identify defects and measure deformations.

Highlights

In pressure storage systems (Figure 1), from 35 to 70 MPa, the most technologically advanced and safest solutions are applied, they have a well-deserved high reputation resulting from their use in transport, mainly over land and water, in stationary systems used for energy generation and hydrogen storage, including systems cooperating with renewable energy sources (RES)
This is because high-pressure systems, and especially composite vessels, are highly efficient, i.e., the values of parameters describing the amount of stored hydrogen or energy in relation to the mass or volume of a storage system
A correctly manufactured liner is of key importance in the whole process of the production and exploitation of a high-pressure type 4 composite vessel used for hydrogen storage

Summary

Introduction

In pressure storage systems (Figure 1), from 35 to 70 MPa, the most technologically advanced and safest solutions are applied, they have a well-deserved high reputation resulting from their use in transport, mainly over land and water, in stationary systems used for energy generation and hydrogen storage, including systems cooperating with renewable energy sources (RES). This is because high-pressure systems, and especially composite vessels, are highly efficient, i.e., the values of parameters describing the amount of stored hydrogen or energy in relation to the mass or volume of a storage system (expressed as system gravimetric capacity or system volumetric capacity, respectively). In comparison with other hydrogen storage methods, e.g., various chemical absorption methods and liquid hydrogen at cryogenic temperatures, they are competitively priced

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Results

Conclusion