INNOVATIVE TECHNOLOGY FOR MAIN PIPELINE OVERHAUL BY INSULATION COATING REPLACEMENT

Vollständiger Abstract

Worum geht es in dieser Arbeit?

Main pipelines are one of the principal methods for hydrocarbon raw materials transportation over long distances. The majority of these pipelines are laid underground. This, in turn, has a number of advantages and disadvantages. For example, when performing certain technological operations aimed at maintaining the operability of an underground pipeline, additional time is required for excavation work, specifically, uncovering the pipeline from the backfill soil that is trapping it. Maintaining the required reliability of a main pipeline during its operation is essential. Safe operation ensures the reliable and uninterrupted operation of the pipeline system, which ensures the timely delivery of the transported product to consumers, prevents losses during hydrocarbon raw materials pumping, and, consequently, protects the environment from pollution.The underground pipeline insulating coating plays a significant role in its safe operation, protecting it from the surrounding aggressive and hazardous environment. Existing insulation coatings can withstand operational loads under pipeline operating conditions for 33–35 years. Therefore, to ensure pipeline safe operation, it is necessary to re-insulate them. Various pipeline repair technologies exist for insulation coating replacement. These typically involve clearing the pipeline of backfill soil, creating a trench large enough for specialized insulation repair equipment, removing the old insulation coating by a cleaning machine in several passes, applying a new waterproofing coating using a specialized insulation machine, testing the adhesion of the new waterproofing coating, and backfilling the underground main pipeline with the new waterproofing coating.The authors propose an innovative technology for re-insulating main pipelines in-line. Using this technology, the length of the repaired section of the pipe where the insulation is replaced can reach over 20 km. The proposed technology ensures the reliability of the insulation coating for up to 50 years and consists of two stages. The first stage involves opening the trench, cleaning the pipeline of old insulation, and preparing the pipeline wall for the application of new waterproofing. The second stage involves applying the new waterproofing using an extruder and laying the pipeline in its designed position, backfilling it with the soil in which it was laid.After completion of the new waterproofing application on the underground main pipeline, the waterproofing coating repair system is removed from the repaired section of the underground pipeline, disassembled, and relocated to the next prepared location for repair work on the underground pipeline with the defective section of the waterproofing coating, which was identified during a series of diagnostic tests.