EFFECT OF USING A NEW GAS SPLITTING TECHNIQUE ON THE PERFORMANCE OF AMINE SWEETENING PROCESS AT REDUCED NATURAL GAS PRESSURES

Abstract

Throughout the duration of any natural gas reservoir, its pressure declines which directly affect the amine sweetening efficiency, so relevant techniques are used nowadays to overcome this problem such as drilling new wells, modifying process parameters that will increase power/heat consumption, using amine blends and re-design the conventional gas sweetening process. The present study aims to find a new solution or modification to the basic amine sweetening process using Aspen HYSYS to overcome the pressure reduction phenomenon. The proposed solution was based on the idea of splitting the raw natural gas entering the absorber into two streams, one entering from the normal bottom tray and the other fed to the middle tray, in order to allow a better sour gas/amine contact area, consequently a better absorption without consuming higher energy. After simulating the conventional amine sweetening process, along with its modified version utilizing Aspen HYSYS, the findings revealed that the modified split gas flow technique increases effectively the absorption of hydrogen sulphide from natural gas by a factor ranging from 53% to 72% compared to the normal amine sweetening process but this applies only at certain feed gas flow rates. At high pressure, both techniques are delivering on-spec. sweet gas, but when pressure is reduced only the modified solution can produce on-spec. sweet gas at relatively feed gas flow rates while the conventional process failed to maintain the H₂S concentration below the maximum allowable limit.