Análise de viabilidade técnica da metodologia NORSOK L-005 para junções parafusadas em válvulas do tipo esfera

Abstract

Among the various industrial sectors, the oil and gas industry stand out as one of the primary consumers of devices known as valves. These devices are crucial for fluid management in liquid, gaseous, or mixed states, playing a critical role in the production and safety of facilities. Industrial valves are designed according to the requirements of international standards and technical specifications, which demand the performance of structural analytical calculations to provide adequate levels of reliability and safety according to the pipeline pressure class. Within the various parts of these devices, the flange system of the body and its bolted joint is extremely important to ensure the ability to contain the fluid pressure within the equipment's enclosure. Additionally, this region of the component exhibits a significant mass concentration due to the strength required to withstand the internal fluid pressure. In this context, this study conducted a comparative analysis between two dimensioned valves: one based on standards applicable in the oil industry (API 6D (2021), ASME-B16.34 (2020), and ABNT NBR 15827 (2022)) and another on the NORSOK L005 (2013) standard, which does not directly address body and cover connection flanges. A case study related to the sizing of the flanged union of the body of a trunnion ball valve was addressed, with a nominal passage diameter of 6", pressure class 600. The methodology of analytical calculations was complemented with finite element method analyses, including linearelastic analysis with stress linearization, elastic-plastic analysis, and localized failure analysis by the elastic-plastic deformation method. The ANSYS software was used for these analyses, following the guidelines of ASME VIII, Division II. As a result of this study, two valves were obtained, both meeting the strength criteria of their respective standards, as well as ASME VIII Division II. However, the valve with body and cover connection flanges sized by the NORSOK L005 (2013) standard showed a 25.7% reduction in mass, an 8.9% reduction in outer diameter, and a 16.9% reduction in total length.