Mechanism of High Temperature Corrosion by Model Naphthenic Acids
Naphthenic acid (NAP) corrosion is one of the major concerns for corrosion engineers in refineries, particularly with the increasing acidity in “opportunity crudes”. However, complex compositions of NAP in crude oil make it difficult to evaluate accurately their corrosive behavior. In the present study, several model acids, including 4-phenylbutyric acid, 1-naphthoic acid, and 4-cyclohexyl pentanoic acid, have been tested in lab scale experiments previous applied to real crude fractions. Pretreatment/challenge protocol tests the corrosive behavior of the model acids under temperature and velocity ranges close to those encountered in refineries. This work demonstrates that the pretreatment of carbon steel and 9Cralloy with model acids yields iron oxide scales with different morphology and chemical composition as determined by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). It is postulated that the formation of the iron oxide scale resulted from the decomposition of iron naphthenate on the surface at high temperatures.
Influencia de la estructura molecular de los ácidos naftenicos extraídos de un crudo ácido venezolano en el proceso de corrosión
Jaimes Parra,Maria Daniela(2018)Influencia de la estructura molecular de los acidos naftenicos extraidos de un crudo acido venezolano en el proceso de corrosion. Trabajo de Grado presentado ante la Universidad Central de Venezuela para optar por el Titulo de Doctor en Ciencias, Mencion Quimica
Study on Electrical Explosion Mechanism and Ignition Characteristics of Copper and Aluminum Powder Under Ignition Solid Propellant
In order to study the characteristic of the electrical explosion of copper and aluminum powders, a multilayer generator was designed, an experimental system was set up, and the parameters of metal powder electrical explosion were measured and analyzed. The results show that the duration of the electrical explosion process increases significantly due to the addition of metal powder. The duration of aluminum powder electrical explosion jet flow is ~86.36 ms due to its self-sustained combustion, which releases a large amount of energy, and a small fraction of aluminum powder particles is not burned. The duration of copper powder electrical explosion jet flow is ~15.84 ms, and most of the copper powder particles are in the solid state. The current pause process is absent; instead, the first discharge process is connected to the second discharge process. The effect of copper powder on the first discharge process is greater than that of aluminum powder. Furthermore, the ignition ability of copper powder electrical explosion to solid propellant is stronger than that of aluminum powder in a closed bomb experiment. These results are indubitably meaningful for the application of metal powder electrical explosion and ignition of solid propellant in an electrothermal chemical gun.