Method for evaluating causticity of naphthenic acids

Abstract

The invention relates to a method for evaluating causticity of naphthenic acids, comprising the following steps: adding quaternary ammonium salt in a corrosion medium, with the addition quantity equal to 0.05-10% of the corrosion medium mass; leading the corrosion medium and a metal specimen to contact and react with each other; characterizing the causticity of acid-contained hydrocarbon oil by the weightlessness of the metal specimen on unit area and in unit time, wherein the negative ions of the quaternary ammonium salt are halide ions; and the total carbon number of the alkyl in the quaternary ammonium salt is 10 to 40. The method can be used for evaluating the causticity of naphthenic acids in acid-contained hydrocarbon oil.

Description

technical field [0001] The invention relates to a method for evaluating the corrosivity of naphthenic acid. Background technique [0002] Naphthenic acid corrosion in oil refining units is a hot spot of concern for oil refining companies at home and abroad, and it is also a difficult problem to be solved urgently. With the deterioration of crude oil, the acid value in crude oil increases year by year, and the naphthenic acid corrosion in oil refining units is also increasingly prominent, seriously threatening the safe production of enterprises. Although naphthenic acid corrosion has been discovered for nearly 80 years, people still lack a systematic and in-depth understanding of the nature of this corrosion phenomenon and its controlling factors. There are two main reasons: (1) Influencing factors of naphthenic acid corrosion It is very complicated, and factors such as temperature, acid value, flow rate, and equipment materials are closely related to this corrosion phenomen...

AI Technical Summary

Problems solved by technology

The rotation method has the advantages of simple equipment and small amount of test solution, but the eddy current caused by the rotation and the relative speed of the solution moving with the rotating test piece reduce its relative speed, which is not enough to generate sufficient shear force; the advantage of the tube flow method is that it can compare It can well simulate the actual working conditions of pipeline scour, and the experimental results have strong practical value, but the system takes up a lot of space, the amount of solution required for the experiment is large, the experiment period is long, and the construction and operation costs of the device are high; The advantage is that it can provide a high impact flow velocity, thus shortening the test period. The disadvantage is that it cannot simulate the actual working conditions well, and the erosion is more serious than the actual situation. In order to obtain a high impact flow velocity, the diameter of the nozzle is generally only 1 ~2mm, easy to block during operation