Safety Analysis And Assessment Of Ultra-high Pressure Reactors

An autofrettaged reactor for ultrahigh pressure polythene, under its operation, is often affected by such factors as loads created at the beginning to operate or the moment to rest, pressure or temperature fluctuation, motion of impulse valves, heat impact during the ultra-temperature decomposition reaction that bring the current issues of crack initiation life, law of residual stress attenuation and nondestructive test for the reactor's wall in the fields of residual stress study, fatigue study and ultrahigh pressure reactor study. Therefore, the research to these problems has an important theoretical and realistic significance and meets the urgent demand for engineering practice.This paper is mainly based on the study of an autofrettaged ultrahigh pressure reactor R401 that has been operated for eleven years in Daqing Petrochemical Company. We have studied a lot about the spreading of crack under the fatigue loads, but a little about the crack initiation life and the fatigue condition under high-low -cycle loads. In accordance with the characteristic of the materiaI-30CrNiMo8, the condition of the reactor operating, and the relational theories of continuum damage mechanics, we establish a formula for the crack initiation life of the reactor, considering the affection of material characteristic, structure, size and loads. The formula has a definite physical meaning and it is proved to be simple and practical, well inoculate with experimental results, satisfy the demand for engineering practice. Experimental results emphasize the influence of high-cycle loads to the fatigue life.In the aspect of investigation of the law of residual stress attenuation, we find the reason for the attenuation of residual stress and set up a formula according to the experimental results and mathematic modification. In the aspect of nondestructive test for the reactor's wall, we develop a convenient and accurate method to meet the practical requirements and successfully carry out nondestructive test to inner walls. We also introduce a formula for residual stress in inner walls and it is proved to be accurate and reliable. The compound sealing structure which is initiated in our country satisfies the demands of ultrahigh pressure(560MPa)down-lead seal. The software for safety analysis and assessment of reactor realizes real-time analysis and assessment, brings scientific management and maintenance for reactor into force, assure the safe and smooth operation of reactor.This paper assesses the operating condition of a reactor through the synthetic analysis and assessment (59#).