REPAIR TECHNOLOGY OF PRODUCT PIPELINES OPERATED IN A HYDROGEN SULFIDE ENVIRONMENT

Abstract

Introduction. The article discusses the improved repair technologies of pipeline material saturated with hydrogen sulfide, which should replace conventional repair methods that ignore operational features in a hydrogen sulfide environment.The aim of this work is to develop a technology for repairing pipelines operated in a hydrogen sulfide environment by manual arc welding using a consumable electrode.Materials and methods. Full-scale experiments were carried out to achieve the goals. A section of an industrial pipeline was selected as a test sample, whose service life in a hydrogen sulfide environment at the hydrocracking unit of an oil refinery equals about 10 years. Degassing, i.e., the removal of diffusion atomic hydrogen from the metal in the repairing area, was carried out using electric heating devices. The surfacing of the pipe edges using a layer of austenitic or ferritic metal was carried out by manual arc welding.Results. The developed technology for repairing pipelines operated in a hydrogen sulfide environment by manual arc welding using a consumable electrode involves degassing and surfacing the edges with metal having the same composition as the parent material. Here, the positive effect of surfacing lies in the fine distribution of non-metallic inclusions in the remolten metal and a favorable change in their shape and chemical composition.Conclusions. The efficiency of the repair technology of industrial pipelines using welding is achieved by taking into account the properties of a transported product and its influence on the welding process. When developing the welding technology of industrial pipelines operated in the hydrogen sulfide environment, such basic measures as preliminary degassing of pipe metal, preliminary surfacing, and heat treatment of pipe edges are substantiated.