Simulation of Sour Water Stripping Unit in Oil Refinery with Consideration of Ammonia Separation

In this research, the sour water unit and its simulation were investigated. Sour water unit of refineries usually has two stripping towers in series. The results of this study showed that with the increase in the volumetric flow rate of the incoming sour water feed, the molar flow of NH3 in the exit gases from the first tower increases. With increasing feed temperature, the NH3 and H2S do not change much until the temperature of 1050C, and after that, the relative molarity of these two substances in the exhaust gases decreases with increasing temperature. By increasing the reflux to the first tower to about 9 m3/hr, the molar flow rate of NH3 gas in the first tower decreases drastically, which actually increases the purity of H2S in the exit gases of this tower and increases the flow of this component in the exit gases from the second tower. Also, with the increase in the temperature of the end of the tower, the flow of NH3 and H2S increases and at a temperature of about 120 0C, all the H2S in the feed enters the exit gases from the first tower and the exit water from the first tower is free of H2S. As a result, it can be concluded that the best temperature for the bottom of the first tower is about 120 0C so that all the H2S is removed from the water and NH3 does not enter the gases leaving the tower in the first tower.