Gas rectification columns are process apparatuses which are very important part of each onshore plant. Sudden failure of these types of columns causes huge daily losses, while fluid leakage can be very dangerous for the people and hazardous for the environment. For that reason, a regular and correct examination of the column is of great importance for the continual process of leading. Together with the detailed examination of the column, a risk-based inspection was applied to maximize savings, both material, time, and costs. The expected remaining service life of rectification columns was also analyzed, while the corrosion rates were calculated according to the various international standards. The minimum required column wall thickness was calculated according to the most commonly used international standard and the obtained difference was analyzed. Detailed analysis of the total risks of the column due to potential failure is presented.

There are the common steel platforms which can be of the eight legged type, or of lightweight four-legged variety. There are also jack-up rigs which are mobile, and tension leg platforms (TLP) which float. With steel fixed platforms the jacket supports the superstructure which contains all necessary facilities. The jacket is built in a fabrication yard and if it is a large six or eight-legged jacket designed to support full production facilities, it may well have modified legs designed as floats, or additional ballast tanks may be installed, so that it can be floated out to the site.

This research provides a detailed investigation into the mechanical properties and microstructural evolution of heat-resistant steel P92 subjected to both initial (i) welding procedures and simulated (ii) repair welding. The study addresses the influence of critical welding parameters, including preheating temperature, heat input, and post-weld heat treatment (PWHT), with a particular emphasis on the metallurgical consequences arising from the application of repair welding thermal cycles. Through the analysis of three welding probes—initially welded pipes using the PF (vertical upwards) and PC (horizontal–vertical) welding positions, and a PF-welded pipe undergoing a simulated repair welding (also in the PF position)—the research compares microstructure in the parent material (PM), weld metal (WM), and heat-affected zone (HAZ). Recognizing the practical limitations and challenges associated with achieving complete removal of the original WM under the limited (in-field) repair welding, this study provides a comprehensive comparative analysis of uniaxial tensile properties, impact toughness evaluated via Charpy V-notch testing, and microhardness measurements conducted at room temperature. Furthermore, the research critically analyzes the influence of the complex thermal cycles experienced during both the initial welding and repair welding procedures to elucidate the practical application limits of this high-alloyed, heat-resistant P92 steel in demanding service conditions.

This paper will present a novel approach to supporting a piece of process equipment subjected to long-term exploitation conditions, with the main goal of improving its reliability and safety. Optimising the supports of the process equipment (in this particular case, 16 autoclaves used for coal drying) began by measuring the load at the support points. It was followed by an analysis based on good engineering practice to develop a new technical solution. The old support solution represented a rigid connection between the autoclave envelope and the supporting structure. Meanwhile, the new approach introduced spring supports, thus providing flexible connections between the Autoclave and the structure. This flexibility ensures that the load on the vessel's shell is reduced significantly and that stress distribution at the support points is uniform. Simultaneously, the load distribution in the structure's support zone is significantly more favourable. The economic benefit of such an approach and a reflection on sustainability are also discussed.

This study provides a comprehensive analysis of the mechanical properties and structural integrity of butt-welded P91 creep-resistant steel pipe joints utilized in high-pressure piping systems. Two pipe specimens with an outer diameter of Ø48.3 mm and a wall thickness of 10.15 mm were welded using the GTAW process in the PC position under controlled heat input, followed by post-weld heat treatment: one without and one with an axial misalignment of e = 1 mm (10% of wall thickness). Both welded pipes underwent an identical thermal cycle. Experimental results, including tensile testing, Charpy V-notch impact toughness at 20 °C, HV10 hardness testing, and macro/microstructural analysis, confirmed the over-matching effect of the W CrMo9-1 filler metal and satisfactory toughness in both the weld metal and heat-affected zone. The experimental data served as input parameters for Engineering Critical Assessment (ECA) using Failure Assessment Diagrams (FAD) according to the BS 7910 standard. The combined effect of multiple defects in welded joints—axial misalignment and a 0.3 mm root micro-crack (representing the lack of root penetration)—was evaluated under designed internal pressures of 200 and 300 bar. The results of the ECA approach indicate that the presence of multiple welding defects does not compromise the structural integrity of P91 welded pipes, provided that PWHT is properly executed. This underscores the critical role of the ECA/FAD methodology in evaluating the operational safety of high-pressure piping systems, as well as the need for thorough weldment characterization prior to service.

Offshore pipeline systems associated with floating platforms operate under complex environmental and operational conditions that significantly influence their structural integrity and inspection requirements. Limited accessibility, harsh marine environments, and time-dependent degradation mechanisms require inspection planning to be supported by structured decision-making frameworks capable of explicitly accounting for both degradation processes and failure consequences. In this study, a Risk-Based Inspection (RBI)-driven integrity assessment is applied to three carbon steel pipeline systems associated with a SPAR offshore platform. The analysis integrates system description, identification of dominant damage mechanisms, and RBI quantification to evaluate probability of failure and consequence-related risk under offshore operating conditions. Internal corrosion is identified as the dominant long-term degradation mechanism for all analyzed pipelines, while external corrosion governs short-term inspection interval definition due to its higher growth rate and sensitivity to insulation characteristics and environmental exposure. Although all pipelines are classified within the same overall qualitative risk category, significant differences in failure probability, risk intensity, and consequence-driven risk behavior are observed, reflecting variations in system configuration, insulation systems, length, and functional role within the offshore production infrastructure. To enable meaningful comparison between pipeline systems of significantly different total lengths, normalized risk indicators per unit length are introduced. These indicators provide additional insight into local risk intensity and spatial risk distribution that are not evident from absolute risk values alone. The results highlight the importance of treating risk as a dynamic quantity rather than a static classification and demonstrate that RBI-based assessment supported by normalized risk metrics can enhance inspection prioritization and maintenance decision-making for SPAR-associated offshore pipeline systems.