Risk Analysis of Central Java Gas Transmission Pipeline by Risk-Based Inspection Method
During the operational period of gas transmission pipeline was found a potential hazard that could result in pipeline failure. As a consequence, the problem of the pipeline failure happening more and more. Economic and environmental factors, as well as human life, be considered to involve the current challenges as structural integrity and safety standards. Therefore, the reliability of structural integrity and security of gas pipelines under various conditions, including the existence of defects should be carefully evaluated. The results of this study were the steps for setting a Risk Level on any instrument using the Risk-Based Inspection API 581 standard and the subsequent results are recommended as an effective inspection planning by Risk Level and Remaining Life Time.
Risks management of Tube Bundle heat exchanger in the petrochemical industries using the Risk-Based Inspection approach
Background and Aims: Identification of hazards and taking constructive measures for their management are a cause for concern in the fields of oil, gas and petrochemical industries. Tube bundle is one of the most important sub-equipments in heat exchangers, where any damage to it could lead to a disturbance in the performance of the heat exchanger stopping the process. The purpose of this study is to identify and manage the failure risks of tubular bundle EA-1101 by using Risk-Based Inspection (RBI). Materials and Methods: Semi- quantitative analysis of risk - based inspection method was used to manage the risk of failure and optimize the inspection of tube bundle (TB) of heat exchange. Necessary information of EA-1101 was collected to carry out the RBI and finally the inspection program was determined using RBI software. All stages of this research were conducted ethically. Results: The results of the RBI analysis showed that the tube bundle failure was occurred in the form of local thickness or uniform reduction. Also, general thinning (uniform) and cooling water corrosion were considered as failure mechanism. The risk level of this sub-equipment was medium (3C) and the effectiveness of inspection method was classified as Highly Effective (A) and Usually Effective (B), according to the API-581 standard. Conclusion: The results showed that suggested method can identify failure mechanisms of these types of equipment with high reliability and high effectiveness inspection program with corrective action plans to manage the risks.
Surface roughness monitoring by singular spectrum analysis of vibration signals
Abstract This study assessed two methods for enhanced surface roughness (Ra) monitoring based on the application of singular spectrum analysis (SSA) to vibrations signals generated in workpiece-cutting tool interaction in CNC finish turning operations i.e., the individual analysis of principal components (I-SSA), and the grouping analysis of correlated principal components (G-SSA). Singular spectrum analysis is a non-parametric technique of time series analysis that decomposes a signal into a set of independent additive time series referred to as principal components. A number of experiments with different cutting conditions were performed to assess surface roughness monitoring using both of these methods. The results show that singular spectrum analysis of vibration signal processing discriminated the frequency ranges effective for predicting surface roughness. Grouping analysis of correlated principal components (G-SSA) proved to be the most efficient method for monitoring surface roughness, with optimum prediction and reliability results at a lower analytical-computational cost. Finally, the results show that singular spectrum analysis is an ideal method for analyzing vibration signals applied to the on-line monitoring of surface roughness.