Research Of The Design And Manufacture Of REAC Lined Tube For Resisting Flow Induced Corrosion

As one of the most important equipment in hydoroprocessing plant, the reactor effluent air cooler (REAC) confronts the condition of hydrogenation process, high pressure and changing temperature, following the development of oil refineries. The unplanned shutdown of equipment which is attributed to the local corrosion of air cooler tubes results in a great loss for the enterprises during processing the crude oil containing chloride. The routine way by improving the materials of tubebundles comes across the cost problem and other failure styles. Therefore, designing and producing a new tube style that is applicable to the harsh running condition of REAC is quite valuable for the oil refineries.The technological process, flow induced corrosion mechanism and anatomy of tubes were analyzed according to the the actual failure cases of leakage in REAC tubebundles. It indicated that the corrosion failure style of tubes that attribute to the local corrosion resulted from ammonium chloride (NH4Cl) deposition. It is proposed a structure of 316L stainless steel lined tubes in REAC to solve the problem of corrosion failure induced from NH4Cl deposition. The structure and mechanical model of lined tube were analyzed by using finite element method. The mechanics behavior and the failure style of tube under different condition was obtained in the finite element analysis software ANSYS. The criteria of mechanic properties were proposed to assess the quality of tubes. The non-linear forming procedure of REAC lined tubes was studied by using ANSYS according to the different forming parameters such as drawing head diameter, friction coefficient and gap, etc. By analyzing the seal welding of tube-tubesheet, heat treatment examination and inspection after manufacture, it proved that the results meet the requirement of bonding strength and heat transfer properties according to the national and professional standards. It certified the stainless steel lined tube qualifies the request of engineering application.The innovative work in this thesis is concluded as follows: the flow induced corrosion failure style in REAC tubes was determined through the corrosion mechanism study. A structure of stainless steel lined tube was proposed to improve the reliability of REAC system. The structure study and mechanic optimization were executed. The behaivior and mechanic status of lined tube were simulated according to the actual running condition. There is also special work of forming effect analysis of different manufacture parameters that is useful for the practical engineering application. The specimen of lined tubes were executed and tested through national standards, of which the result qualified the requirement in engineering application and achieves the economic efficiency.