Quantitative risk assessment and risk reduction of integrated acid gas enrichment and amine regeneration process using Aspen Plus dynamic simulation

Abstract

Dynamic simulation provides a novel tool in risk assessment that is capable of predicting process behavior in different situations, quantifying unsafe process boundaries and examining the propagation of deviations through the process. This study investigated the most frequent disturbances in the integrated acid gas enrichment and amine regeneration process in the natural gas refinery including disturbances in amine regeneration column temperature, feed flow rate, pressure, and gas leakage from the top product stream. Using Aspen Plus dynamics simulations, the consequences of various deviation scenarios and a detailed analysis of the reasons for the occurrence of the consequences were elaborated. The calculated propagation time from the beginning of each disturbance to the occurrence of an accident makes it possible for the operators to plan the necessary arrangements and effective measures based on the available response time. Furthermore, the consequences of flooding and weeping leading to changes in product quality are numerically ranked to facilitate comparing and prioritizing these consequences. Finally, based on the simulation results, new protective layers were designed to prevent various high-risk consequences. The complexity of the integrated process evaluated in this study illustrates the generalizability of the HAZOP dynamic method to achieve new results in chemical process hazard analysis thus serving as a useful tool for process safety specialists.

Keywords

• Quantitative risk assessment
• Dynamic simulation
• Acid gas enrichment
• Amine regeneration process
• Control system design