Cracking Reasons and Countermeasures of Heat Exchanger Tube Bundle of Solvent Regeneration Tower in an Aromatics Extraction Unit

In response to the problem of two cracks and leaks in a heat exchanger bundle of a solvent regeneration tower E-1013 in the aromatics extraction unit of Sichuan Petrochemical, the chemical composition and microstructure of the bundle were analyzed. Through electron microscopy scanning and energy spectrum analysis, combined with the operating conditions of the heat exchanger and the material structure of the bundle, the main reasons for the cracking of the bundle were analyzed. The results indicate that there was localized stress concentration at the welding point between the tube bundle and the tube plate, and fatigue cracking occurs in the tube bundle under the action of alternating vibration loads. By controlling the operating temperature of the regeneration tower, the inlet and outlet temperature of the heat exchanger tube bundle, and selecting austenitic stainless steel above 304, fatigue cracking accidents of the tube bundle could be effectively controlled.