Сибирский федеральный университет

Перевод названия: Mathematical simulation of hexadecane oxidation processes

Тип публикации: статья из журнала

Год издания: 2013

Ключевые слова: гексадекан, hexadecane, high-temperature oxidation, Oxygen-containing organic compounds, dynamic model, высокотемпературное окисление, кислородсодержащие органические соединения, динамическая модель

Аннотация: Исследован процесс жидкофазного окисления гексадекана, традиционной модели нефтяных углеводородов. Определен состав продуктов окисления с помощью газовой хроматографии с масс-спектрометрическим детектированием (ГХ/МС). На основании полученных результатов количественного анализа построено семейство регрессионных динамических моделей протекания процесса окисления. Анализ моделей для диффузионного режима указывает на наличие «колебательной составляющей» процесса, которая связана со спонтанным разложением гидропероксидов и не может быть учтена в рамках предложенного подхода. It is considered that the boundary of the transition from initial stages of chain oxidation of hydrocarbons to the deep stages is a maximum of the hydroperoxides concentration. However, the accumulation of the hydroperoxides may be accompanied by an exothermic process of their decomposition. Thus, the concentration of peroxide compounds gives not always an idea about the true picture of oxidation. Of interest is the dynamics of accumulation of oxidation products at different stages of oxidation. This would evaluate the oxidative stability of fuels depending on the composition of the oxidation products more accurately, and to predict what changes in their operational properties will take place, not taking into account the concentration of hydroperoxides and non-isothermal flow of oxidation. Experimental estimation of the dynamics of the accumulation of products of oxidation of n-hexadecane (as a model of middle-distillate petroleum fraction) in different modes oxidation at 170 Degrees was held. The dynamics of hexadecane loss was estimated also. We received the information about the products of oxidation by means of gas chromatography with mass spectro-metric detection (GC/MS) by chromatograph Agilent 7890A. Data oxidation of hexadecane in diffusion mode showed that the increase of the rate of loss of hexadecane coincide with the growth of the speed of accumulation of the alcohols. In our opinion, it is possible to judge about the degree of oxidation of the fuel by the concentrations of alcohols. Based on the obtained results of the quantitative analysis, a family of regression dynamic models of the process of oxidation is constructed. A sequential estimation of quantities (expressed in molls of carbon atoms) of hexadecane, alcohols, and carbonyls, has been performed. For the processes' description ordinary linear differential equations of the 1 st and 2 nd order have been used. One obtains equation parameters using genetic algorithm (GA) with MSE optimization criterion. Models and optimization procedure were implemented in MATLAB. The complexity of modeling process is caused by small samples of hexadecane and oxidation products. Indeed, the cost of the necessary reagents and laboratory analysis influence on the samples size (five measurement within 2-hour experiment duration in the kinetic mode, as well as 13 measurement for the diffusion mode). Therefore, the chosen modeling strategy and accuracy corresponds to samples limitation. Analysis of the models for diffusion mode indicates the presence of a «oscillation part» of the process, which is connected with the spontaneous decay of the hydroperoxides and cannot be taken into account in the framework of the proposed approach.

Журнал: Вестник Томского государственного университета. Управление, вычислительная техника и информатика

Выпуск журнала: № 4

Номера страниц: 5-15

ISSN журнала: 19988605

Место издания: Томск

Издатель: Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования Национальный исследовательский Томский государственный университет

• Агафонов Евгений Дмитриевич (Сибирский федеральный университет)
• Орловская Нина Федоровна (Сибирский федеральный университет)

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