Abstract:

This study focuses on the serious corrosion problem faced by the overhead line of a certain atmospheric distillation tower top (overhead) for processing high acid crude oil. The online corrosion monitoring data of the overhead line has exceeded the control indicators for a long time, and many corrosion pits and thinning areas were found during the inspection, posing a risk of corrosion leakage. By analyzing the fixed-point thickness measurement, probe corrosion rate, probe corrosion scale, and corrosive medium of overhead sulfur-containing wastewater, combined with the calculation of the medium flow rate in the overhead line, two main factors that exacerbate the corrosion process are identified: the presence of a high concentration (390-600mg/L) of various small molecular organic acids in the overhead line medium, and the high flow rate of the medium at the top of the tower. Two targeted measures have been taken to address the corrosion issue of the overhead line: controlling the flow rate of naphtha at the top of the tower to not exceed 150t/h to reduce the accumulation of corrosive media in the system; optimizing the selection of neutralizing agents to ensure that they can effectively neutralize acidic substances in the system, thereby significantly reducing the corrosion rate. The implementation of these measures has improved the corrosion condition of the overhead line, extended the service life of the equipment, and ensured the long-term, stable, and safe operation of the unit.

Key words: high acid crude oil, atmospheric distillation tower, vapor line, corrosion rate, sulfur-containing wastewater, organic acid, gas phase flow rate, neutralizing agent

摘要：

某加工高酸原油的常减压装置的常压塔塔顶（常顶）挥发线，在在线腐蚀探针监测数据长时间超过控制指标，检修发现常顶挥发线有较多蚀坑减薄部位，存在腐蚀泄漏风险。通过分析定点测厚情况、探针腐蚀速率、探针腐蚀污垢、常顶含硫污水腐蚀介质，结合常顶挥发线中介质流速的计算，识别出两个加剧腐蚀过程的主要因素：常顶挥发线介质中存在浓度高达390～600mg/L的多种小分子有机酸，以及塔顶介质的高流速。针对常顶挥发线的腐蚀问题，采取了两项有针对性的措施：控制常顶石脑油流量不超过150t/h，以减少腐蚀介质在系统内的积累；优化中和剂的选型，确保中和剂能够有效中和系统中的酸性物质，从而显著降低腐蚀速率。通过实施这些工艺措施，改善了常顶挥发线的腐蚀情况，延长了设备的使用寿命，确保了装置能够长期、稳定、安全地运行。

关键词: 高酸原油, 常压塔, 挥发线, 腐蚀速率, 含硫污水, 有机酸, 气相流速, 中和剂