Abstract

The failure anatomy and simulation of high pressure air cooler bundle in hydrogenation unit are analyzed. Based on the typical working condition data, DCS and Lims data during the calibration period of the unit, the process simulation of the hydrogenation effluent system was carried out in Aspen Plus, and the cooling separation process of the hydrogenation effluent was simulated by using the material reverse sequence backward pushing method. According to the distribution of oil, gas and water multiphase flow in the air cooler, the temperature of ammonium salt crystallization, the content of liquid water, the concentration of ammonium sulphate hydrogenation, the corrosion factor and the pH value were calculated. The results showed that there were corrosion risks of ammonium salt crystallization and erosion corrosion in the air cooler. At the same time, according to the state and physical parameters, the erosion risk of air cooler inlet pipe and air cooler is predicted and analyzed, and the characteristic parameters such as shear stress, mass transfer coefficient and water phase fraction are used to represent the erosion risk. The anatomic analysis results of the failed bundle are verified by the process and fluid mechanics simulation. In view of corrosion analysis, corrosion prevention and control are carried out by means of technological protection, mainly by adjusting the water injection volume and water injection location. Based on the design of resistance to flow corrosion, the compound liner of air cooler tube bundle was modified. A corrosion expert supervision system was developed to monitor the running state of the hydrogenation effluent system in real time. The process calculation model and fluid dynamics simulation prediction model are embedded into the system to calculate each characteristic parameter and present the corrosion status of the current device to the enterprise, so that the enterprise can timely take measures to avoid safety accidents.

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