【Haichuan’s Best Practices】Guangzhou Petrochemical Uses Online Cleaning to Solve Oil Accumulation Issues in Stripping Towers

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Guangzhou Petrochemical uses online cleaning to address oil accumulation in the stripping tower 2019-02-13 Source: Sinopec News Network Print article Petrochemical news “On January 24, an online water wash was carried out on the stripping tower, eliminating the risk of oil accumulation within it. Through continuous optimization of operations, the control parameters of the stripping tower and the quality of the product were improved, resulting in stable operation of the tower. ”On January 28, Liu Shan, the supervisor of Unit 4’s wastewater stripping unit at Guangzhou Petrochemical’s Refining Department 3, said during the shift handover. The No. 4 wastewater stripping unit is used to treat sulfur-containing wastewater from various units such as coking, distillation, and leaching, as well as from certain pipeline networks. As the operating cycle of the unit lengthens, some light oils in the sulfur-containing wastewater vaporize along with the steam at the bottom of the stripping tower and rise upward, gradually accumulating in the upper part of the tower and causing severe temperature fluctuations in that area. If not addressed promptly, it will affect the proper operation of the entire stripping tower as well as the quality control of the purified water; moreover, the presence of ammonia in the acidic gases at the top of the tower can lead to pipeline blockages. To resolve the issue of oil accumulation in the stripping tower as quickly as possible, the plant technician prepared a water washing plan for the stripping tower based on its actual operating conditions ； Hazard identification and risk assessment were conducted during the washing process, and 5 corresponding countermeasures were established ； A new table for standard washing procedures has been added, laying the foundation for online washing of the stripping tower. At 9:00 on January 24, the staff on duty began the washing process in accordance with the plan; they contacted the production control center to adjust processes such as the closed-loop circulation of purified water and the addition of alkali, and disabled the on-line ammonia nitrogen analysis instruments. During the washing of the stripping tower, fresh water was introduced to intermittently adjust the ratio of cold to hot feed flow rates multiple times, thereby flushing the oil accumulated inside the tower to its bottom, where it was collected through the oil collection line at the bottom of the tower. At the same time, steam is introduced at the bottom of the stripping tower to achieve a better washing effect. During the water washing process, closely monitor the operation of the pumps and the pressure in the raw water tank to detect and address any issues promptly. After nearly 8 hours of water washing, the risk of oil accumulation in the stripping tower was essentially eliminated. Once the quality of the purified water is confirmed to be satisfactory through testing and analysis, the device returns to its normal operating mode. (Huang Minqing, Chen Haitao)