Abstract: A two-tower sour water stripping unit is studied in this paper. Based on a detailed analysis for the mechanism of sour water stripping process, the process is simulated by sour water package in PRO/II software, focusing on the factors affecting the energy consumption of the unit, such as for H2S stripping tower, the ratio of cold feed, inlet temperature of hot feed and feeding position; for NH3 stripping tower, the ratio of recycle condensed wastewater, feed temperature and inlet position. The optimal operation parameters are proposed as follows: for H2S stripping tower, the ratio of the cold feed is 0.02, the hot feed temperature is 408 K; for NH3 stripping tower, the feed temperature is 435 K, the optimal feed inlet position is at 2nd plate and without recycle of condensed wastewater. Options for saving energy-use are also obtained: canceling the heat exchange between hot feed water of H2S stripping tower and NH3 containing water; adding heat exchange among top gas of NH3 stripping tower, steam condensate of reboilers and the hot feed water of H2S stripping tower. Simulation results show that after adopting these measures, the energy consumption of this unit reduces by 22.3%.

Key words: sour water stripping unit, process simulation , energy saving