Iranian Journal of Oil and Gas Science and Technology

Abstract Gas compression systems in petrochemical facilities are subjected to extreme pressures, cyclic loading, and variable humidity levels, which collectively challenge the integrity of lubricating films. This study investigates the performance of ester-based lubricants, which benefit from polar molecular structures and enhanced hydrolytic stability, in forming robust boundary lubrication layers under such demanding conditions. Experiments were conducted using a pin-on-disk tribometer to simulate compressor stresses, employing polyol esters and diesters across a relative humidity (RH) range of 20% to 80%. Adhering to ASTM G99 standards, friction and wear metrics were quantified, followed by detailed characterization of the resultant films via scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results indicate that these esters generate denser and more ordered films in humid environments, achieving up to 30% wear reduction relative to conventional mineral oils. Complementary molecular dynamics (MD) simulations corroborate these observations, illustrating enhanced adhesion of ester functional groups to metallic substrates in the presence of moisture. These insights underscore the potential of humidity as a beneficial factor in lubrication efficacy, informing the development of optimized formulations for severe industrial applications. Such advancements could extend equipment service life, minimize downtime, and promote environmentally sustainable alternatives. Future efforts should prioritize field validations and formulation refinements for operational deployment.

Abstract Optimization of transportation for organizational projects is paramount, as identifying and evaluating transportation barriers constitutes key strategic decisions for managers and decision-makers. This study focuses on three main objectives: identifying the factors influencing lean logistics and transportation barriers, clarifying the interrelationships among the research criteria, and determining their relative importance and ranking in petroleum product distribution. A hybrid model was employed to achieve these objectives. First, the Delphi method was utilized to facilitate the examination of interrelationships among the research criteria. Additionally, fuzzy multi-criteria decision-making techniques, including the fuzzy Analytic Hierarchy Process, were applied to assign specific weights to the criteria. Subsequently, the VIKOR method enabled the prioritization of these criteria. The findings of this study confirm the existence of significant relationships between lean logistics, lean criteria, and transportation barriers, highlighting that managerial barriers and lean managerial logistics are the most critical obstacles and factors, respectively, in petroleum product distribution. These findings can assist managers in improving distribution processes and mitigating key transportation barriers.

Abstract A novel friction stir welding method called projection friction stir spot welding (PFSSW) was introduced to produce safe and reliable welds by using a pinless tool and a specially-designed projection on the surface of a backing anvil. This projection along with the tool rotation speed plays an important role in having a reliable joint with excellent mechanical properties and good surface appearance. This welding technique can be widely developed in oil and gas, as well as in automotive, aerospace, and transportation, industry. The effect of tool rotation speed (1000, 1600, 2000 rpm) on the hardness, microstructure, and mechanical properties of 2024 aluminum alloy sheets was investigated. The surface appearance of the welding zone showed that the keyhole was not formed, and the appearance of the weld was almost smooth. Fracture surfaces of the failed specimens present the interfacial fracture at the tool rotation speed of 1000 rpm and circumferential fracture at tool rotation speed of 1600 and 2000 rpm.