Ammonium Salt Depositing Mechanism And Numerical Simulation Of Multi-physics Interaction For Reactor Effluent Air Coolers

The flow corrosion mechanism of reactor effluent air coolers (REAC) includes multi-phase flow erosion-corrosion and corrosion caused by deposition of ammonium salt. The survey indicates that failure of deposition of ammonium chloride is frequent and very dangerous. Analysis and forecast for the failure don't recived enough attention and study indepth all the while, because the quality of ammonium chloride is small and the process of failure is complicated. This paper studies process of ammonium chloride deposition in REAC, mechanism of deposition under the multi-physics interaction, establishes the model of process of ammonium chloride deposition and achieves analysis quantitatively. The results can be used in designing and optimizing running of REAC.In this paper, based on the process of REAC system and typical operating conditions and taken frequent failure of Yangzi REAC system as study object, the following work was studied: (1) The compositon and physical parameter of multi-phase flow are obtained using the software of HYSYS; (2) The process of ammonium chloride crystal-deposition is analyzed based on theory of multi-physics interaction and failure mechanism of ammonium chloride deposition is obtained; (3) According to the coupling of flow field, temperature distribution and concentration distribution, the deposition model of ammonium chloride in REAC is established, and the deposition was caculated quantitatively using the CFD software; (4) In accordance with anatomical experiment, the reliability of multiphysics numerical simulation was veritafied, moveover, the effect of N and Cl content in raw material, operation pressure, inlet temperature, capacity and water injection volume on deposition of ammonium chloride was disscused.The findings of this paper have promising application in risk prediction, optimum operation, security evaluation, technical modification and so on, and will provide the theoretical bases for security, stability, long-period operation of REAC.The main innovation in this paper is (1) Multi-physics coupled model of deposition in REAC is established based on relationship of coupling variable.(2) based on law of the ammonium chloride deposition under different influencing factor, the method to predict deposition is proposed.