Study On Corrosion Behavior Of Filler In Vacuum Tower Of High Acid Crude Oil Refining

The exploration of offshore oil is an extension of the exploitation of land oil,which is experiencing a development process from the mainland to the sea.With the development of offshore oil production,the corrosion effect of marine oil on the distillation unit is rapid increasing.Corrosion of vacuum tower packing in distillation unit is the most obvious and direct.In the paper,the corrosion behavior of marine oil in vacuum tower with distillation processis analyzed with the characteristics of low sulfur and acid in marine crude oil.As an example of CNOOC Z Petrochemical Co.,Ltd,according to the decompression equipment running status,the production data was collected,and the operation of decompression tower packing was understood.The immersion tests were employed in high temperature reactor to simulate acid number,sulfur content and temperature of vacuum tower.The effect of temperature,soaking time,acid number,sulfur content on the corrosion rate of 304 SS,316Land 317 L as the filler was investigated.The corrosion morphologies of various materials under different factors were observed by scanning electron microscope.The main influence factors on corrosion was analyzed,and the corrosion behavior of vacuum tower packing was discussed.Experimental results show that the naphthenic acid combined with a little sulfur caused the serious corrosion of less two-wire and three-wire filters.The effect of temperature as the decisive factor on corrosion is very obvious.At a specific temperature(270?),the acid value as an important factor influenced corrosion.The corrosion rate changed from fast to slow and then steady state with the increasing time when the acid value and temperature were constant.The key role of incoming material acceptance was indicated by the survey.The improvement measures including the material,process and operation of equipment were provided according to the experimental tests and field results.The results could provide a support to the daily operation and technical reform for the vacuum packed tower in CNOOC refinery.The paper could provide the important guarantee and strong support to early realize the long period operation of the key equipment in decompression device,for the sustainable development of enterprises and the realization of "boutique refinery".