关键词: 连续重整, 汽包系统, 蒸汽换热管, 泄漏, 垢样分析, 氧腐蚀, 垢下腐蚀

Abstract:

The 2^# continuous reforming unit of SINOPEC Yangzi Petrochemical Co., Ltd. adopts domestic ultra-low pressure continuous reforming technology. During the operation of the unit, there was a leak in the steam heat exchange pipe of the steam drum system in the convection section of the furnace, which forced the unit to be shut down for maintenance. A series of studies have been conducted on failed heat exchange pipes, including perforation analysis, material composition analysis, and energy spectrum analysis. Through perforation analysis, it is determined that corrosion perforation occurs on the inner wall and extends towards the outer wall. Through energy spectrum analysis and X-ray diffraction analysis, it is found that the main corrosion products of the scale sample on the inner wall of the heat exchange pipe are Fe₂O₃ and Fe₃O₄. Combined with the oxygen content data of the deoxygenated water, it is determined that there is oxygen corrosion phenomenon. After cleaning the scale sample, it is found that the sediment amount exceeds 600 g/m³, and the scale deposition amount exceeds the standard. Based on the above, the cause of the leakage is the corrosion perforation of the heat exchange pipe in the steam drum system, which extends from the inside to the outside of the pipe under the combined action of oxygen corrosion and underdeposit corrosion. In response to the reasons for the leakage, this article proposes preventive measures from aspects such as water quality monitoring, furnace shutdown protection, and regular spot checks.

Key words: continuous reforming, steam drum system, steam heat exchange pipe, leakage, scale sample analysis, oxygen corrosion, underdeposit corrosion