Damage Condition of GFRP Large Scrubber Used in Acid-Gas Environment for Long Term

This study investigated damage condition of the large GFRP scrubber which was used to cleanse acid-gas for 35 years without large maintenance. Samples were obtained from four typical parts of the scrubber and optically observed on the inside surfaces and the cross-sections in detail. Ultrasonic-echo inspection and bending tests were further carried out for the obtained samples. The results showed that fishnet-like cracks were formed on the inside surface of the scrubber. Since acid-gas or clearing fluid invaded the inside of GFRP through the fishnet-like cracks, the damage such as delamination was induced in the chopped strand mats existing under the surfacing mats. However, the bending strength of each part was suitably maintained because the damage was generated in limited area. Furthermore, a relatively clear relationship was found between the ultrasonic-echo data and the residual bending strength. This result suggested the possibility of practical application of the ultrasonic-echo inspection for GFRP products.