Mathematical modeling of a new method of transportation of viscous petroleum products at low air temperatures

High viscosity petroleum products such as fuel oils and cracking residues are widely used as marine and boiler fuels both in Russia and in its exports. Conveying viscous petroleum products at low air temperatures has a high cost due to the unloading and cleaning processes of the transport tanks. Refined petroleum product cools and solidifies during transportation, becoming highly viscous, making it impossible to drain it without preheating to restore fluidity. Emerging difficulties are common to all countries with long winters and geographically wide areas. To justify a new method of rail transport of viscous petroleum products while maintaining their high temperature and fluidity by suppressing the natural convection of the petroleum product at the stage of filling the tanker. Temperature field calculations using the finite element method and the ANSYS R18.2 package are presented. The business process of the proposed transport method is universal for all modes of transportation. Using Petri nets and simulation modelling, it is investigated using the example of cleaning a tank car boiler from highly viscous residual oil products. You must perform these operations periodically during the operation of the tank wagon, and they are mandatory before every scheduled inspection and repair. Viscous oil products can be transported in a new way, the duration of the cleaning process of the tank wagon boiler is reduced by three times and the amount of water consumed is reduced by one and a half times.

METROLOGICAL SUPPORT OF PETROLEUM PRODUCT TESTING FOR PURPOSES OF CONFORMITY ASSESSMENT

С использованием методов системного анализа обоснована системная цель метрологического обеспечения испытаний нефтепродуктов – получение точной, полной и достоверной измерительной информации о составе и свойствах нефтепродуктов, которая достигается через решение двух частных целей: а) создание условий для получения результатов испытаний с требуемой точностью; б) достижение такого состояния процесса испытаний, которое обеспечивало бы получение точной и достоверной измерительной информации о составе и свойствах нефтепродуктов. Раскрытие первой и второй частных целей образует структуру системы метрологического обеспечения испытаний нефтепродуктов, представляющую собой совокупность традиционных элементов и процессов метрологического обеспечения и процедур управления процессом испытаний нефтепродуктов. В разработанной структуре системы метрологического обеспечения испытаний нефтепродуктов используются как известные общепризнанные элементы и процессы метрологического обеспечения, так и новые элементы и процессы, отражающие специфику процесса испытаний как объекта метрологического обеспечения. В частности, для подтверждения метрологической пригодности методик испытаний нефтепродуктов предложено использовать процедуры валидации и верификации, показана необходимость верификации операторов, проводящих испытания. В целях снижения погрешности испытаний нефтепродуктов обоснована необходимость включения в систему метрологического обеспечения мероприятий по управлению процессом испытаний нефтепродуктов в лаборатории. Показана такая последовательность действий по метрологическому обеспечению испытаний нефтепродуктов, которая позволяет добиться такого состояния процесса испытаний, в котором погрешность получаемых результатов находится в определенных статистически обоснованных границах, а достоверность результатов испытания подтверждается стабильностью значений погрешности. Applying the methods of system analysis, the system goal of metrological support for petroleum product testing is justified; the goal is to obtain accurate, complete, reliable measurement information about the composition and properties of petroleum products, which is achieved via solving two subgoals: а) creating conditions for obtaining the testing results having the required accuracy; б) achieving such a state of the testing progress that would ensure the receipt of accurate and reliable measurement information about the petroleum product composition and properties. The disclosure of the first and second subgoals forms the structure of the metrological support system intended for testing of petroleum products, which is a complex of conventional elements and processes of metrological support and procedures for controlling the process of petroleum product testing. In the structure of the metrological support system under development purposed for petroleum product testing, both well-known and generally recognized elements and processes of metrological support, as well as new elements and processes that capture the specific features of the testing process as a subject of metrological support. In particular, it is proposed to use validation and verification procedures to confirm the metrological applicability of testing methods intended for petroleum products, and the need for verification of operators, who carry out the tests, is given. In order to reduce the petroleum testing inaccuracy, the need to include measures to control the process of petroleum product testing in a lab by way of the metrological support system is justified. The following sequence of actions for metrological support of petroleum products testing is shown; it allows achieving such a state of the testing process, in which the tolerance of the obtained results is within certain statistically adjusted limits and the reliability of the test results is confirmed by the stability of the tolerance values.

Assessment of the contribution of the air-vapor mixture volume exceeding over the volumes injected to oil and petroleum product losses from evaporation

В настоящее время при экспериментальном определении потерь нефтепродуктов от «больших дыханий» резервуаров используют формулу Черникина - Валявского. При этом «однако» не учитывается, что объем вытесняемой в атмосферу паровоздушной смеси, как правило, превышает объем закачиваемой нефти (нефтепродукта). Соответствующий параметр - коэффициент превышения, - по экспериментальным данным, может принимать значения более 8. До недавнего времени не до конца были ясны даже причины этого явления, соответственно, эмпирические зависимости для расчета коэффициента превышения не учитывали всех влияющих факторов. Авторами статьи на основе уравнения Менделеева - Клапейрона в дифференциальной форме получено аналитическое выражение для вычисления среднего коэффициента превышения. Установлено, что данная величина зависит от молярной массы и температуры паровоздушной смеси в начале и конце закачки, а также от соотношения объемов газового пространства резервуара и закачиваемого продукта. Для анализа полученной зависимости был спланирован и проведен вычислительный эксперимент, предусматривающий изменение определяющих параметров в широком диапазоне. Расчеты выполнялись для нефти и бензина. По результатам 25 вычислительных «опытов» определено, что при операциях с бензином средний коэффициент превышения (за одну операцию заполнения резервуара) в исследованном диапазоне температур принимает значения от 1,029 до 1,678, а при операциях с нефтью - от 1,016 до 1,338, то есть, как правило, превышает погрешность инструментальных замеров потерь нефти (нефтепродуктов) от испарения. Математическое ожидание рассматриваемой величины при операциях с бензином составляет 1,26, с нефтью - 1,16. Таким образом, учет среднего коэффициента превышения при обработке результатов инструментальных измерений потерь углеводородов от испарений вследствие «больших дыханий» резервуаров является обязательным. Currently, the Chernikin - Valyavsky formula is used in the experimental determination of petroleum product losses from “large breaths” of reservoirs. However, it does not take into account that the volume of air-vapor mixture displaced into the atmosphere usually exceeds the volume of pumped oil/petroleum product. The corresponding parameter, the excess ratio, according to the experimental data can have values of more than 8. Until recently, even the causes of this phenomenon were not completely clear, and thus, the empirical dependencies for calculating the excess ratio did not take into account all the influencing factors. Based on the Mendeleev-Clapeyron equation in differential form, the analytic expression to calculate the average excess ratio was obtained. It was found that this value depends on the molar mass and temperature of the air-vapor mixture at the beginning and the end of the injection, as well as on the ratio of the tank gas space volume and the injected product volume. To analyze the resulting dependency, a computational experiment involving changes in the defining parameters over a wide range was planned and conducted. The calculations were performed for oil and gasoline. According to the results of 25 computational experiments, it was determined that during operations with gasoline the average excess ratio (per one tank filling operation) in the investigated temperature range has values from 1.029 to 1.678, and during operations with oil - from 1.016 to 1.338; that generally exceeds the instrument error of oil/petroleum product losses from vaporization measurement. The mathematical expectation of the value in question during operations with gasoline is 1.26, it is 1.16 with oil. It is therefore mandatory to take into account the average excess ratio when processing the results of instrumental measurements of hydrocarbon losses from evaporation due to “large breaths” of reservoirs.

Analysis of Knocking Characteristic in Dual Fuel Engine - the Effects on Diethyl Ether

In Diesel engines, where fuel is pumped into highly compressed air towards the end of the compression cycle, knocking is more or less unavoidable. By this time there is already a quantity of fuel in the combustion chamber which will first burn in areas of higher oxygen density before the full charge is combusted. The sudden rise in pressure and temperature produces the distinctive 'knock' or 'clatter' diesel, some of which must be allowed in engine design. The aim of knock control strategies is to try to maximize the trade-off between protecting the engine from damaging knock incidents, and optimizing the output torque of the engine. Knock events are a random process and independent. Knock controllers can't be programmed in a deterministic model. Due to the random nature of arriving knock events, a single time history simulation or experiment of knock control methods cannot provide a repeatable measurement of the controller efficiency. The desired trade-off must therefore be achieved in a stochastic context that could provide an appropriate environment for designing and evaluating the output of various knock control strategies with rigorous statistical properties. Clutching characteristics of a dual fuel diesel engine with direct injection of diesel and a liquid petroleum product in dual fuel mode. The engine is tested for knock reduction by adding Diethyl ether in to the diesel along with Liquid petroleum product. Variation of knocking was plotted with respect to different parameters and the result booted as knocking is minimized by the addition of diethyl ether.