Abstract: During the operation of the 20 000 m³ rolling curtain type dry-seal gas holders, pistons hit against the inner walls of the gas holders, resulting in equipment accidents covering damage of diaphragms & walls, severe deformation of T-fence and serious gas leakage. Through analysis and demonstration, it is considered that the continuous rainstorm submerged the steam pipelines and caused sharp decrease of steam temperature, so the units were forced to shut down; after the shutdown, all devices vented intensively in large quantities, resulting in large fluctuations in the amount and pressure of gas entering the gas holders. This caused violent shaking of the piston. After the occurring of the abnormal operation of the piston, no effective measures were taken to close the inlet and outlet valves in time to stabilize the piston as soon as possible, which aggravated the degree of the damage to the gas holders. Aiming at the damage to the gas holders, effective repair plans were developed and necessary monitoring devices were added so as to ensure the normal operation of the gas holders.

Key words: gas holder, failure, cause analysis, treatment options