The Analysis Of Corrosive Medium On The Fractionating Tower Overhead Circulation Oil And Selection Of Corrosion Inhibitors

In recent years,due to processing of high-acid crude oil,the overhead circulation of atmospheric tower,catalytic tower and coked tower appeared frequently the phenomenon of the pipe wall thinning,leak,the pump salt deposition and other new issues,especially the corrosion of top cycle of catalytic tower was more serious.The production of the device,safety,equipment corrosion were severely affected.Therefore,this paper focuses on analysis of the corrosion medium and corrosion products in catalytic fractionator overhead recycle oil and condensed water to explore the causes of corrosion in catalytic top cycle,and select/synthesissynthesise suitable corrosion inhibitor for processing high acid crude oil in distillation tower furtherly.The analysis results of corrosion medium and corrosion products in overhead condensed water and top cycle oil showed catalytic top cycle oil contained chloride ions,mercaptan and hydrogen sulfide.The content of total sulfur,basic nitrogen and phenol were high..The water soluble acid p H was less than 7.The results of GC-MS analysis showed that catalytic top cycle oil had many kinds of phenolic compounds.Catalytic condensation water contained a certain amount of chloride ion,sulfide.The results of XRD,XRF analysis showed that catalytic top cycle corrosion products were mainly iron sulphide,iron oxide.The actual tower top cycle oil was taken as corrosion environment furtherly and the hydrogen chloride,hydrogen sulfide and the chemical compound of oxygen,sulfur,nitrogen in the oil were investigated to conclude the influence on corrosion of top cycle oil.The main reasons for serious corrosion of the top cycle were hydrogen chloride,hydrogen sulfide,ammonia,phenolic compounds.The ammonium salt?ammonium chloride,ammonium sulfide?,carbon dioxide and high temperature for top cycle were the important factor causing corrosion of catalytic top cycle.Selecting merchant inhibitors,self-synthesizing water-soluble imidazoline inhibitors and oil-soluble imidazoline inhibitors respectively,the results showed that the effect of merchant inhibitors is MLZ> YQZ> 7019 in the the HCl-H₂S-water system;Comprehensive result in the HCl-water system and HCl-H₂S-water system can show that self-synthesizing oil-soluble corrosion inhibitors performed OBI> OCI> OAI,better than self-synthesizing water-soluble corrosion inhibitors.All kinds of corrosion inhibitiors performed in the order of OBI>MLZ>YQZ>7019>EA.The self-synthesizing of oil-soluble corrosion inhibitor OBI had the best performance,and had a good inhibition effect for the catalytic top cycle oil.