Study On Simulation Of Multiphase Flow And Prediction Of Erosion Attack Breakage For REAC Pipes

The hydrocracking REAC pipes are special equipments, and easy to lead to serious accidents, for they suffer from the erosion of multiphase flow under the environment of high-pressure hydrogen. Since hydrocracking and high severity hydrotreating process was put into use, the failure of REAC and its relative pipes has been haunting the units' stable long run, then the study on its corrosion mechanism has become a focus in the field. In recent years, NACE T-8 committee, UOP and API have been doing comprehensive research and studying the failure mechanism of REAC. The research shows that the influence of REAC corrosion was very complicated, among which the flow behavior of reacting effluent and the content distribution of corrosive medium are two critical factors. While, till now the research only make qualitative analysis of this phenomenon, without comprehensive research on the quantity analysis between the pipe flow to the pipe corrosion. So the corrosion prediction and safety assessment of the REAC pipelines cannot be done.Since high-sulfur crude oil was processed in China, the cases of REAC failures tend to be more and more. The paper, based on the research of RHAC erosion mechanism, intends to find out the sources under the condition where the process capability was expanded and reconstructed; using the numerical simulated by CFD and no-dimension analysis for multiphase flow fluid motion and corrosion situation, analyses the erosion method of reacting effluent upon REAC pipes for extensive situations; checks the emulation result with the analysis of domestic REAC pipes failures, no destructed test in using and corrosion accelerated test, etc; finally brings out the prediction method of REAC corrosion and the guideline of safety assessment. The results of the research will help to improve the design, manufacture, operation, test, prediction and evaluation of domestic REAC to the international level, andrealize the closed management of the REAC. It will own a lot to the stability of hydrocracking units, and produce lots of economic benefits and social effects.The innovations in the paper as following: Using quantity analysis on corrosive medium and the flow motion, the paper shows the tangible impact of corrosion of the reacting effluent, multiphase flow physical property and flow behavior upon corrosion failure; clarifies the mechanism of REAC corrosion failure, then bring out the principle of the erosion failure of multiphase reacting effluent upon carbonsteel REAC pipes for extensive applications; in order to realize closed management, gives out the prediction method of the erosion failures of REAC pipes, the risk test in using and safety assessment guidelines.