Environmental analysis of Acid Gas Sweetening with DEA

Abstract

Natural gas has wide applications throughout many sectors, but it needs to comply with specific standards to ensure efficient utilization. Therefore, it is required to reduce the impurities in natural gas through the process of purification, also known as acid gas sweetening. Acid gas sweetening involves the usage of amines, which are basic compounds that bind with acidic components such as hydrogen sulfide and carbon dioxide, forming weak bonds. The acid gas sweetening process is based on several separation processes, where this report will mainly target the distillation column. In this report, a detailed study has been carried out on the installation column using process simulation Aspen HYSYS V10) and the manual steps of the solution column design using the McCabe-Thiele method. The results were then compared with each other, in which it has been found that the comparison is not fair at the slightest. This is because of the fact that the distillation column design on Aspen HYSYS was based on a multi-component system while the manual design calculations were based on the binary system. Therefore, a list of recommendations and advice were made to even out the comparison and improve the accuracy of the study. One of these recommendations included manually designing the distillation column based on a multi-component system, to unify the systems in both methods. Although distillation columns have proven to be effective in separating components based on volatilities, it would be recommended to use a phase separator since it is more effective due to the fact that the boiling points deviations between every component is vast, making it easy to separate every component since they are in different phases. In this study, a safety assessment has been conducted on the process, in which the natural gas stream and the whole process has been analyzed. The severity of natural gas in the acid gas sweetening process has been deduced using the DOW index. The process units and equipment were then reviewed for safety considerations using the hazard operability (HAZOP) study, utilizing a qualitative analysis technique to highlight the main risks which can be endured during operations and their effects on the equipment and its surroundings, with actions which can be implemented on how to mitigate the risks of such events to come true. The actions are presented in modified P&ID’s to visualize the control systems, alarms and valve systems which can be installed onto the equipment.