Reason Analysis And Technologies Study On Salt Deposition On The Top Of Atmospheric And Vacuum Distillation Tower Of Crude Oil

As to the current phenomenon of salt deposition of atmospheric and vacuum columns in Anqing oil refining units, this paper analyzes the composition and content of salt deposit, find the main causes, puts forward pertinent solutions to weaken the salt deposition effect from three aspects, as far as the salt deposition mechanism being studied.Through the analysis and determination of washing water samples from Anqing Sinopec, Fe2+and NH4+have a high content in cation and Cl-high in anion. The main component of salt deposit are confirmed as NH4C1and FeCl2through ionic charge balance calculation. The injection of ammonia in tower top and crude oil and the add additives is the nitrogen source of salt deposit, the chloride source mainly comes from hydrolysis or thermal decomposition of inorganic chlorine salt and organic chloride, and the iron source are mainly from dew point corrosion and salt deposit electrical corrosion of the devices. That the coexistence of NH4-and Cl-in columns cause the formation and decomposition of NH4CI salt and gradually froms salt deposition are validated by pilot-scale experiments with self-assembly simulation of salt deposition distillation tower.Results indicate that chlorine transfer agent can greatly improve the organochlorine removal rate of electrical desalting process.25-30μg/g addition have the best organochlorine removal effect, when adding30μg/g agent, the organochlorine removal rate reaches more than70%. Organic amines have a good prevention and clearation effect to salt deposition, especially ethanolamine (MEA) in the best. Under the same concentration (200ppm) of ammonium chloride, compared with blank group froms salt deposition in the top in20minutes, ethanolamine with a addition of600μg/g injected into the tower top can effectively reduce total chlorine content of the tower side-draws and no salt deposition phenomenon has bee observed in the process. Furthermore, MEA of60μg/g can effectively eliminate the NH4C1salt deposition which in a content of80μg/g in30mins. As to the salt deposition which have formed in distillation tower top, intermittent washing tower operation using a certain concentration of monoethanolamine or its aqueous solution can help to eliminate the salt deposit fast and effectively and to keep stable production.