Study on the hydraulic condition of absorption tower of CGH unit for increasing the desulfurization capacity; simulation and execution results

Hydro-desulfurization processes are widely used in oil refineries to increase the quality of gasoline. The sulfur compounds react with hydrogen to produce hydrogen sulfide (H2S) gas. Hydrogen sulfide is absorbed on the absorption tower with an amine solution. In this study, the increase in desulfurization capacity was investigated by simulating the CGH unit of the IKORC (Imam Khomeini Oil Refinery Company). First, this unit was simulated with Aspen Hysys 11 software, which is accurate for refining processes. The simulation validity was obtained when the software output matched the vendor calculations and data. After ensuring the accuracy of the simulation, the maximum amount of amine flow has been obtained. This amount of amine has the maximum absorption of hydrogen sulfide. Any changes in temperature, pressure and the flow of gas and liquid streams can lead the absorption tower to destructive phenomena. The flooding in the absorption tower is the most significant effect of increasing the amine flow. This study purposed finding the maximum amine flow, away from flooding. For gasoline production with Euro 5 standard, maximum desulfurization is desirable, requiring the maximum amines flow in the adsorption tower. Finally, after presenting the results of this study, these changes in the process were implemented in the CGH unit. The execution of the obtained results strengthens the practical aspect of this study and confirms the simulation’s accuracy.