Risk and Impact Assessments of Explosion from Natural Gas Leaks in A Power Plant Located in an Industrial Park

Abstract

This study focuses on assessing the risks associated with natural gas leakage in a combined cycle power plant in Thailand, where natural gas serves as the primary fuel. Given the high flammability of natural gas, the potential for fire and explosion necessitates a comprehensive evaluation to enhance preventive and emergency preparedness measures. The research employs the ALOHA process hazard analysis software to generate models, primarily utilizing the HAZOP method, in order to identify the most critical scenarios for risk assessment. The investigation uncovers two critical events that can lead to natural gas leakage within the power plant: leakage in the natural gas pipeline system (specifically, the discharge line) and leakage at the Gas Compressor Receiver Tank. Corrosion is identified as the primary risk factor contributing to leakage. Furthermore, the study reveals that a 4-inch hole in the natural gas pipeline has a significantly greater impact than a 0.25-inch leak in the Gas Compressor Receiver Tank. In terms of the consequences, the study finds that a flash fire resulting in a natural gas concentration of 30,000 ppm has a potential impact radius of 558 meters. For jet fires, where the thermal radiation reaches 10 kW/m², the affected distance is approximately 33 meters. Moreover, in the event of an explosion with an overpressure of 8 Psi, the affected distance extends to approximately 427 meters. To mitigate the harmful effects of these scenarios, specific preventive measures are proposed. These measures include implementing preventive maintenance practices for high-risk components such as pipeline flange joints and fittings, defining safety regulations for restricted areas, incorporating emergency response instructions into the existing emergency plan, and establishing new assembly points based on the modeling results. By conducting this comprehensive risk assessment and proposing targeted preventive measures, this study aims to enhance the safety and emergency preparedness protocols in combined cycle power plants, thereby mitigating the potential risks associated with natural gas leakage.