Research On Low Temperature Dew Point Corrosion Protection And Injection Nozzle Of Atmospheric Distillation Unit Overhead System

With the worsening of crude oil around the world,the trend of high sulfur and high acidity brings new challenges to the safety and smooth operation of refinery units.Therefore,the research on corrosion protection of refining equipment and pipelines has attracted the attention of researchers.The authors reviewed the low temperature dew point corrosion mechanism,corrosion protection,anti-corrosion injection nozzle and nozzle research methods of atmospheric distillation units overhead system,and analyzed the existing problems.Through the investigation and data collection of the actual operating conditions of the atmospheric distillation units system.According to GB/T 30579-2014,comprehensive analysis of the material properties,operating temperature,pressure,production process,structure material of the system,designed the corrosion scheme of the atmospheric distillation units overhead system,and revealed the mechanism of dew point corrosion.The causes of dew point corrosion were studied from two aspects:crude oil quality and sulfur-containing sewage at the distillation units overhead system.From the analysis of the main factors affecting the dew point corrosion,it is determined that the operating pressure and steam content of the overhead system are the key factors for changing the dew point temperature.The oil-gas-liquid three-phase equilibrium dew point temperature calculation model was established by Aspen software,and compared with the actual operation data of the atmospheric distillation units overhead system to improve the calculation model.The dew point calculation model is used to predict the oil and gas dew point of the overhead system,so as to optimize the process parameters such as water injection amount and operating temperature of the overhead system,which has important guiding significance for actual production.Comprehensive analysis of the injection process conditions of the atmospheric distillation overhead system and the characteristics of the mechanical spray nozzle,and select the pressure-swirling nozzle for the anti-corrosion injection.The flow field inside and near the nozzle area was simulated by Fluent and verified with relevant document.The liquid film thickness of the nozzle and the spray angle of the near nozzle area were selected as the evaluation indexes of the nozzle performance.According to this index,judged the simulated flow field of nozzle structure under different factors.The influence law of various factors on nozzle performance was obtained by analyzing the evaluation data,and the combination of excellent factors.