Effect Of Sulfur And Chlorine Content Of Crude Oil On Corrosion Of The Atmospheric-vacuum Distillation Unit And Countermeasures

As the primary device of an oil refinery,the atmospheric-vacuum distillation unit is influenced strongly by the the corrosion problem caused by the changes of raw materials.In this paper,the author selects the atmospheric-vacuum distillation unit of Harbin Refinery as the research object.Harbin Oil Refinery is affiliated to China National Petroleum Corporation（Group）with an annual crude processing capacity of 4.2 million tons.In the late 2000s,the crude oil was mainly from Daqing Oilfield.These years,with more Russian crude added,the content of sulphur,salt,chlorine and other corrosive media in the raw materials has been on the increase.Meanwhile,as Daqing Oilfield enters the middle and late stage of extraction,More oil displacement agent has been added to rise the crude oil output,which makes the composition of crude oil more complex.This brings more risk of corrosion and leakage to the primary processing device and subsequent secondary processing equipment.It has seriously affected the operation of the device.Based on the situation,research is carried out to find the locations of devices where corrosion is prone to happen,especially the vulnerable positions which are exposed to high and low temperatures when crude oil is processed in the atmospheric-vacuum distillation unit.Some anti-corrosion measures and suggestions which includes three aspects（corrosion monitoring,process corrosion protection,material selection）are also put forward according to this study results.The main research work includes:（1）Looking up and retrieving documents home and abroad on atmospheric-vacuum equipment corrosion and corrosion protection,equipment reliability,monitoring and other related data;doing in-depth research and analyzing the equipment corrosion situation that the chemical plant is facing after the Rusian crude oil is added.（2）Finding the locations of devices where corrosion is likely to happen.（3）Finding the principles and bases of the equipment selection for the high and low temperature parts by means of theoretically calculating.（4）Perfecting the countermeasures of electrode-salting in process anti-corrosion through analysis,accounting and routine industrial tests.Based on the research,conclusion can be drawn that the crude oil processed by atmospheric-vacuum distillation unit of Harbin Oil Refinery belongs to low sulfur and low acid crude oil.According to theoretically calculating,the material selection of high temperature parts is reasonable,and the anti-corrosion effect is good.Moreover,in the low-temperature parts,the corrosion of the"three tops"and the condensation cooling system caused by Hydrochloric acid（HCL+H₂S+H₂O）can be effectively controlled by improving the efficiency of electric desalting and adding organic chlorine dechlorination agent.By now,the key parts and pipelines of the device run smoothly and the corrosion is effectively prevented and controlled.Through the research work of this paper,we can fully understand the corrosion mechanism of the atmospheric-vacuum distillation device after the content of crude oil changes,and then take measures to prevent and control the risk of equipment corrosion.This paper also shows its highlights-it provides a new theory and some methods to solve the corrosion problems of the current atmospheric and vacuum device.Therefore,it has important theoretical significance and practical application value to ensure the safety of the refinery production.It also helps improve the economic benefit of refining enterprises.