Investigation on the Flow Induced Erosion-Corrosion Failure of Hydrocracking Air Cooler Systems and Optimization Study

The flow induced erosion-corrosion of a hydrocracking reactor effluent air cooler (REAC) system normally occurs locally and abruptly, which leads to the high risk of unplanned shutdown and even catastrophic accidents. To study the typical failure cases induced by the high-sulfur and chloride-containing raw oil in the process of refining, numerical simulation of technical process and fluid dynamics parameters are performed on softwares of HYSYS and CFD, and the rules of multiphase flow erosion and ammonium salts deposition are analyzed. Analytical results are in good agreement with actual failure instance and thus the reliability of the predictive method is validated. A corrosion-control research system, consisting of mechanism research, numerical simulation, experimental verification and similarity theory correction, is established. The critical characteristics of multiphase flow deposition and erosion are obtained. And the system to control the flow induced erosion-corrosion, which can be widely applied in various conditions, is formed on the basis of “avoiding blockage and controlling erosion” conception. Moreover, this paper proposes an optimum design based on the degree of unbalancedness and a frame of the REAC Real-time Diagnosis Expert Software for guiding the optimum design. The method above will be beneficial to the promotion and modification of related criteria and regulations in the future.