Predicting the Useful Life of Gas Cylinders in the Course of Technical Inspection

Abstract

The present study is devoted to evaluating the influence of the number of technical inspection cycles on the remaining life of gas cylinders with different methods of cleaning of the inner surface of the equipment and with different compositions of the corrosive media. The thickness of the wall of the cylindrical part, floor, and neck of a gas cylinder is calculated as a function of the number of cycles of technical inspection, employing different methods of cleaning the internal surface of the cylinder, including mechanical treatment with chains, shot blasting, and a pulsating flow of shot in a fluidized bed. The reduction in the thickness of the wall of the vessel is analyzed in the course of corrosive and erosive action of different working media and it is found that the cylindrical part of the cylinder is the zone that is the most susceptible to damage. Treatment with a pulsating flow of shot in a fluidized bed during technical diagnostics makes it possible to realize more uniform removal of the surface layer of metal throughout the internal volume of the gas cylinder as compared to conventional shot blasting and, ultimately, to reduce internal stresses in the material and increase the life of the vessel. Where condensate is present, the greatest damage is found in the bottom and lower cylindrical part of cylinders used to store nitrogen and carbon dioxide.