Scientific Journal of KubSAU

The most important physical properties that characterize the substance are density and saturated vapor pressure (SVP). These parameters are required for the development of new technical processes in the petroleum and chemical industries, design of pipelines, pumping and fuel equipment, etc. Existing methods for calculating of density near and on the saturation lines are imperfect, and finding of the analytic dependence of SVP of petroleum products from all defining parameters associated with great difficulties. The purpose of present work is an experimental research and development of methods for calculating the density (specific volume) near and on saturation lines, and saturated vapor pressure of gasoline straight-run fraction derived from petroleums from three fields: Mangyshlaksky, Trinity-Anastasevsky and West Siberian. The choice of objects for research is due to the necessity of creating methods for calculating of density and SVP of oils obtained from various hydrocarbon group composition petroleums. Area of state parameters in the present work by temperature (20 ÷ 320°C) and pressure (0,03 ÷ 30 MPa) provides the ability to research gasoline fractions to supercritical regions. Measurement of density and SVP of petroleum fractions performed with help of a specially created for this purpose experimental installation

At calculations, we have used the next assumptions: 1. Not excluded systematic errors distributed with equal probability; 2. Random errors are normally distributed; 3. Total error is the composition of not excluded systematic and random errors. In calculating of measurement error of pressure, we proceeded from working formula. The confidence interval of each variable less than instrumental error, therefore, to characterize the total error of the measured value P, we use the instrumental errors of all variables. In estimating of temperature measurement error was consider the systematic and random error. To estimate random error we used measurement data of the specific volume of water on six isotherms. Obtained values were compared with published data. As an approximate estimate of the random error of our experimental data, we can take it as a total for all the isotherms of the specific volume in comparison with the published data. For studied fractions confidence limit of total error of measurement results located in the range of 0,03 ч 0,1%. At temperatures close to the critical increasing influence of errors of reference and the error associated with the introduction of corrections on the thermal expansion of the piezometer. In the two-phase area confidence limit of total error increases and located between 0,08 ч 0,15%. This is due to the sharp increase in this area of reference error of pressure and error in determining to the weight of the substance in the piezometer

In this article, there are descriptions of ventilation systems of municipal and industrial buildings. We consider the scheme of natural ventilation and ventilation with mechanical drive. In agriculture production, processes accompanied by the releasing into the air of premises various harmful substances: gases and vapors, excess of heat and moisture. The source of the fumes and gases are various technological processes. People, animals and birds in the premises, release carbon dioxide and other gases. Sources of heat gain are the people, animals and birds, solar radiation, production equipment and so on. For optimization of parameters of the air environment, satisfying the hygienic requirements, need to install ventilation. The ventilation system – it is a set of devices for handling, transportation, supply and removal of air. The advantage of this article is the systematization of ventilation systems of production premises. We have identified the main flows of indoor air and placement of exhaust shafts. Greatest interest are the systems operating year-round or during the heat period and exhaust systems equipped with control devices in the form of a throttle valves or gate valves and a device for cleaning the air. We give sufficient attention to the thermal regime of premises, heat losses and heat gain through protecting designs. We indicated that a significant effect on the thermal state of premises might be provided by humidity level of fences, as well as potential of heat and moisture transfer

The article describes the methods of calibration and working measurements, planning of experiment and experimental data processing, characterized objects of study and provides illustrations of research results of P-t depending for petroleum fractions. We have described the results of generalization of density (specific volume) of the examined samples in the liquid and on the saturation line and SVP in the two-phase region. The article shows that existing methods of calculation based primarily on the results of the study of the density and SVP of individual hydrocarbons and extremely limited experimental data of petroleum products. We have detected a necessity of creation calculation methods based on reliable experimental data, providing greater accuracy, substantiated choice of directions for research SVP and density of petroleum products. Modern technology of petroleum processing and using of petroleum products requires the creation of more perfect installation for the study of SVP of substances and obtaining experimental data with greater accuracy. Generalized analytic dependence of SVP of petroleum products from all determining parameters have not yet been received. Therefore, experimental determination of this pressure should be the basis of the calculation of any device, because the calculations of petroleum products by the formulas and nomograms obtained with considerable error

The static method is the most common, because it is applicable for measuring SVP of substances in wide ranges of temperatures and pressures. The essence of the method consists in measuring of vapor pressure in equilibrium with its liquid at a given temperature. Dynamic method is based on measurement of the boiling point of the liquid at a certain pressure. Saturation method of moving gas used in the case when the SVP does not exceed a few mm Hg. The method consists the following: the liquid is passed through the inert gas and saturated with vapor of liquids and then it flows into a cooler where the absorbed vapors are condensed. Knowing the amount of absorbed liquid and gas, as well as their molecular weight, allow us calculate saturated vapor pressure of the liquid. Knudsen effusion method is applicable for the measurement of very low pressures (up to 100 Pa). This method consists in researching of depending between the pressure and volume of saturated steam at a constant temperature. At the point of saturation an isotherm should have a break and turn into a straight line. Chromatographic method is based on complete chromatographic analysis of liquid and calculating the sum of partial pressures of all mixture components. Also, the article has a description of existing experimental installation for these researches and their advantages and disadvantages compared with each other

In the article we show the results of pilot studies of petrol and oil fractions, their main physical and chemical properties, density and DNP, a liquid phase, two-phase area, critical area and boundary curves

This article presents the issues related to the application of electrical ozonation to enhance seed germination. The calculations confirming the theoretical conclusions were made

In the article we present the results of pilot studies of petrol and oil fractions; their main physical and chemical properties, density and DNP, a liquid phase, two-phase area, critical area and boundary curves are considered

In the article we have performed a definition of the critical parameters of petroleum fractions - temperature, pressure and density. We have also performed a comparison of the experimental results with the calculations to select the method of calculation, the most similar to the experimental results. We have shown the main results and conclusions