Translated Abstract
With the increasing demand of petroleum and short supply on the contrary, more and more inferior crude oil are processed in refineries, that leads to more serious corrosion problem within refining equipments, corrosion failures may result in tremendous economic loss, disastrous casualty and enviromental pollution. Therefore, refinery enterprises must pay more attention to the corrosion problem and take measures to control the corrosion, thus it is an important research regarding with reliable safe operation of the units. As the first process in refinery, the atmospheric and vacuum distillation unit suffers most severely corrosion environment. This thesis aimed at the multiple corrosion in atmospheric and vacuum distillation unit, the distribution of sulfur contents in different fractions were obtained through a flowsheet simulation model using Aspen Plus. Based on the sulfur distribution, considering flow parameters, operation conditions, structures, materials and other factors of equipments and pipelines, sulfur-containing corrosion loops were divided and different sulfur-containing corrosion systems were classified. According to corresponding corrosion mechanism of every corrosion loop, proper prevention measures were proposed. According to site investigation in refineries and corrosion loops, “one removal and multi injections” process anticorrosion technology was applied to inhibit HCl-H2S-H2O multiple corrosion system. The reasons of corrosion were analyzed and the parameters influencing corrosion rate were calculated to put forward suggestions for improving process anticorrosion measures in refineries.Inhibition efficiency and mechanism of different neutralization corrosion inhibitors were studied by corrosion weight loss experiments, electrochemical measurements, and surface observation and analysis technology. The optimum addition amount is 40 mg•L-1 in experimental conditions. The impact on the inhibition effect of H2S content and pH value of corrosive medium were discussed, when the concentration of H2S increased, the depolarization of cathodic reaction was accelerated by dissociation H+, and the adsorption of HS— made the metal lose electrons easier；thus low pH value could accelerate hydrogen evolution reaction. The neutralization corrosion inhibitors could inhibit hydrogen evolution reaction by neutralizing part of H+ in corrosive solution, and prevented metal corrosion by adsorbing on metal surface to form a barrier between HS— and metal. The inhibition effects of different neutralization corrosion inhibitors were tested for comparison and differences among inhibitors were analyzed. The experimental results provide theoretical basis and engineering guide for application and modification of corrosion inhibitor in crude oil refining processes.
Translated Keyword
[Crude Oil Refining UnitMultiple Corrosion SystemCorrosion LoopProcess Anticorrosion]
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