Media corrosiveness and materials resistance at presence of aggressive carbon dioxide

At the present stage of gas field development, the products of many mining facilities have increased content of corrosive CO2 . The corrosive effect of CO2 on steel equipment and pipelines is determined by the conditions of its use. CO2 has a potentially wide range of usage at oil and gas facilities for solving technological problems (during production, transportation, storage, etc.). Simulation tests and analysis were carried out to assess the corrosion effect of CO2 on typical steels (carbon, low-alloy and alloyed) used at field facilities. Gas production facilities demonstrate several corrosion formation zones: lower part of the pipe (when moisture accumulates) and top of the pipe (in case of moisture condensation). The authors have analyzed the main factors influencing the intensity of carbon dioxide corrosion processes at hydrocarbon production with CO2 , its storage and use for various technological purposes. The main mechanism for development of carbon dioxide corrosion is presence/condensation of moisture, which triggers the corrosion process, including the formation of local defects (pits, etc.). X-ray diffraction was used for the analysis of corrosion products formed on the steel surface, which can have different protective characteristics depending on the phase state (amorphous or crystalline).

Research of design solutions of water cooling systems for tanks

Установки водяного охлаждения резервуаров являются частью системы автоматического пожаротушения резервуарного парка и представляют собой комплекс устройств, оборудования и трубопроводов. Непосредственное охлаждение стенки резервуара осуществляется через верхнее горизонтальное кольцо орошения, выполненное в виде перфорированного трубопровода или трубопровода с оросителями. При этом до настоящего времени не была определена зависимость фактически защищаемой площади стенки от расходов воды, подаваемой через отверстия и/или оросители при их различном положении по отношению к стенке и верхней кромке резервуара. Цель исследования - экспериментальное определение оптимальных конструктивных и технологических решений элементов установок водяного охлаждения резервуара. Для изучения процессов теплового нагрева и охлаждения боковой поверхности резервуара проведены гидравлические и огневые испытания моделей секции установки водяного охлаждения - горизонтального кольца орошения. По результатам испытаний определена эффективность различных конструкций в зависимости от изменяемых технологических параметров (давления и расхода воды в кольце орошения), диаметра отверстий перфорированного трубопровода и шага между ними, угла расположения устройств подачи воды относительно горизонтальной поверхности сечения резервуара, расстояния от кольца орошения до стенки резервуара и его верхней кромки. Water cooling units for tanks are a part of automatic fire extinguishing system of the tank farm and represent a complex of units, equipment and pipelines. Tank wall is cooled down directly through upper horizontal spray distribution ring, made in the form of a perforated pipeline or a pipeline with sprinklers. With this, correlation between actually protected area of the wall and flow rate of water supplied through the holes and/or sprinklers at their different positions in relation to the wall and the upper edge of the tank, has not been determined so far. The purpose of the study is to experimentally determine the optimal design and technological solutions of the elements of tank water cooling units. To study the processes of thermal heating and cooling of the side surface of the tank, hydraulic and fire tests of models of the section of the water cooling unit (the horizontal spray distribution ring) were carried out. According to the test results, the efficiency of various structures was determined depending on the technological parameters being changed (pressure and water flow in the spray distribution ring), diameter of the holes of the perforated pipeline and pitch between them, angle of the water supply units relative to the horizontal surface of the tank section, distance from the spray distribution ring to the tank wall and its upper edge.

Study of hydrogenation and corrosion of steel equipment and pipelines at the production facilities of H2S -containing hydrocarbon raw materials

The impact of hydrogen sulfide raw materials on steel equipment and pipelines is associated not only with corrosion processes, but also with the hydrogenation of used carbon and low-alloy steels. This can lead to the loss of their strength properties and the subsequent destruction of equipment operated under conditions of increased operating pressures. Such corrosive-mechanical effects associated with the penetration of hydrogen into steel are the most dangerous from the point of view of the safety and reliability of the operation of facilities for the production of hydrocarbon fluids. The effect of H2S on the main types of structural steels was investigated according to the results of autoclave tests. The formation of blistering (blistering) and cracks on the surface of steels due to the effect of hydrogen on the steel was recorded. A study of the phase composition of corrosion products and their possible effect on the processes of corrosion and hydrogenation of steel has been carried out.

Basic calculation methods of investigation of circumstances and mechanism of man-made explosions

The article purpose is to analyze the danger of man-made explosions and provide calculation methods for determining the mechanism of the occurrence of an explosion during forensic examinations of the study of the circumstances and mechanism of man-made explosions. The relevance of the article is caused by the fact that present-day production and everyday life cannot dispense with the usage of combustible and explosive substances. The particular attention to be paid to emergency prevention related to explosives, as well as the research to determine the mechanism of man-made explosions. The research on the mechanism of man-made explosions will make it possible to determine the technical cause of their occurrence, to analyze for what reason and for whose fault the event occurred, and also what measures should be taken to minimize the likelihood of such situations occurence. It is noted that in order to obtain reliable conclusions about the mechanism of man-made explosions, it is necessary to use scientifically based methods and methodologies allowing us to assess the extent of destruction. The degree of destruction of surrounding building structures and harm to people depends on overpressure caused as the result of a significant expansion of the explosion products and their spread to all directions from the center of explosion. The most frequent causes of explosions in the explosive object are: destruction and damage to production tanks, equipment and pipelines; deviation from production regulations (excess pressure and temperature of equipment operating mode), low-quality control of equipment and work while conducting require work, and untimely or poor-quality maintenance of technological equipment. The main calculation methods for the research of the man-made explosions in open areas, indoors, and limited space are given, which will allow to systematize the research process and analyze the flow of explosions in specific situations, and to establish a mechanism for their occurrence when conducting forensic examinations of the circumstances and mechanism of man-made explosions.

The INVESTIGATION OF VARIOUS PHOSPHATE CORROSION INHIBITORS IN CARBON DIOXIDE

Corrosion leads to huge losses every year, and solving this problem is an important task. One of the effective methods of corrosion protection of equipment and pipelines in the oil industry is the use of corrosion inhibitors. Inhibitory protection is the most technological and effective way to control corrosion of oilfield equipment. The article deals with phosphate corrosion inhibitors of complex action in a carbon dioxide environment. The method of corrosion testing is generally accepted. Quantitative indicators of corrosion processes were calculated using formulas, and the measurement uncertainty was estimated using an algorithm using the Student's coefficient with a confidence probability of 0.95. In the course of the work, potentiometric determination of the pH of corrosive media using a combined glass electrode and an ionomer, conductometric and photocolorimetric determination of the content of iron (III) with potassium rhodanide, as well as methods of infrared spectroscopy and electron microscopy were carried out.

Monitoring of technological environments at petrochemical plants as a means of ensuring their safe operation

The cooling recycled water of petrochemical enterprises is characterized by high corrosion activity, unstable composition and, due to the evaporation of water in cooling towers, a constant increase in the concentration of dissolved salts, suspended particles and organic pollutants. Some of the salts formed by divalent metal ions fall out in the form of deposits, and the water is satu-rated with chlorine, sulfate, phosphate, and carbonations and becomes corrosive. At the same time, the corrosion activity of reservoir water varies widely depending on the saturation of cer-tain ions and other ingredients. It is established that monitoring the composition of recycled water and determining the corrosion rate of equipment and pipelines, carried out within 1-2 months, allow us to build a regression model of the dependence of the corrosion rate on the technical parameters of water, with which we can accurately calculate the values of the corrosion rate on the evaporation coefficient. Monitoring of technological environments and optimization of their composition through mathematical modeling will significantly improve the safety of equipment and pipelines operation at oil refining enterprises. Keywords: corrosion inhibitor; scale inhibitor; biocide; water circulation system; evaporation coefficient; monitoring; cooling water; regression model.

Assessment of the steel corrosion rate at the infrastructure facilities of hydrocarbon deposits as a function of the mineralization and temperature

Active and promising hydrocarbon deposits, including those on the sea shelf, are often characterized by an increased content of corrosive carbon dioxide and hydrogen sulfide. Corrosive gases present in the produced crude is a serious threat to the safety and reliability of the equipment and pipelines operating at gas production facilities. We present the results of assessing the dependence of the steel corrosion rate in the presence of CO2 on the salinity and temperature. The experimental data were processed using the methods of mathematical statistics. It is shown that the obtained dependences provide calculation of the corrosion rate with a high degree of reliability. The impact of each factor (salinity and temperature) on the steel corrosion rate was evaluated separately. The results obtained can be used to control and predict the danger of corrosion destruction of the infrastructure facilities of oil – gas fields.

Development and study of corrosion inhibitors based on tall oil

One of the serious troubles faced by the oil and gas industry is corrosion wear of equipment and pipelines. The major part of failures of the oilfield equipment and pipelines is the result of corrosion damage, so protection of equipment from corrosion is one of the most urgent scientific and technical issues. One of the most common ways to control corrosion is inhibitor protection. The paper presents the results of studies of corrosion inhibitors synthesized on the basis of polyethylene polyamines and three varieties of light tall oil in the presence of alcohol solvents using the stillage residue of butyl alcohols rectification. The optimal parameters of synthesis and the ratio of basic raw reactants and solvents have been determined. The inhibitory properties of the synthesized samples were evaluated by changes in the rate of corrosion and the value of their protective efficiency. It has been shown that the best of the synthesized samples is not inferior to the industrial reactant Sonkor 9601 in terms of the protective effectiveness, and in the area of low concentrations (up to 40 g/t) exceeds the basic inhibitor.