Risk Assessment Analysis of Pressure Vessel Refrigerant Accumulator at PT XYZ

Abstract

The Refrigerant Accumulator equipment is a pressure vessel located within the production system unit, namely the Dew Point Control (DPC) Unit. The Refrigerant Accumulator is a crucial component within the DPC Unit as it serves as a reservoir for the Propane refrigerant liquid. In case of a failure of this equipment, it would halt the entire process in the DPC Unit and impact the control of gas dew point that is transmitted to consumers through pipelines. Hence, a more effective method is required to prevent failures in the Refrigerant Accumulator. One of the methods that can assist in more effective inspection is Risk-Based Inspection (RBI). Risk-Based Inspection is a risk-based inspection methodology, where the main output obtained is an inspection plan determined based on the risk of the equipment. It prioritizes inspections for equipment with higher risk of damage, thus optimizing equipment maintenance and aiding companies in establishing effective maintenance strategies. Therefore, this study aims to analyze the risk level of the Refrigerant Accumulator equipment using the Risk-Based Inspection method according to API 581, determine the risk level of the Refrigerant Accumulator equipment, and provide appropriate inspection planning recommendations for the Refrigerant Accumulator equipment. Based on the results of this study, the Risk-Based Inspection analysis yielded values for Probability of Failure (PoF), Area-based Consequence (CA), and Financial Consequence (FC) through quantitative calculations based on the steps outlined in API 581. The PoF value is 5.011×10-6, the CA value is 3,316.36 ft2, and the FC value is $22,746,756.91. From the analysis results, the risk level of the Refrigerant Accumulator equipment is categorized as Medium-Risk, with a Probability of Failure of 5.011×10-6 in category 1 and a Consequence of Failure of $22,746,756.91 in category E. Consequently, the final category is 1E, with a remaining life of 33.7 years. Based on the obtained risk level, the recommended inspection planning is to conduct the next inspection on December 2031, using Visual Inspection method with 100% surface coverage and Phased Array Ultrasonic Testing (PAUT) with 90% surface coverage.