RU2030742C1 - Composition of standard samples for adjustment and control of devices for quick test of temperature of initial and final points of light petroleum products distillation - Google Patents

Abstract

FIELD: analytic chemistry. SUBSTANCE: proposed composition contains (vol% ): N-octane 10-25, N-nonane 15-30, N-undecane 25-55, N-dodecane 15-40, N-pentadecane 5-10. EFFECT: improves composition quality. 2 tbl

Description

The invention relates to metrological certification of test methods and instruments for monitoring the composition and properties of substances, namely for checking and tuning the NKP-E express analyzer, designed to determine the temperatures of the beginning and end of the distillation of gasolines, diesel fuels, fuels for jet engines and other petroleum products in laboratory conditions in order to control the quality of oil products after their transportation. The temperature stability of the beginning and end of boiling of test mixtures ensures the accuracy of tuning and calibration of NKP-E, which is especially important when analyzing fuels for jet engines used in aviation. The average values of the required temperatures are determined in accordance with GOST 10227-86 [1] and are accordingly equal to:
start of distillation 135 ... 150 ^о С
end of distillation 235 ... 250 ^о С
In practice, for verification and adjustment of instruments for controlling the composition and properties of substances, control samples or standard samples (CO) are used - simulators of the analyzed products [2].

 Source products for CO must have physical and chemical stability, uniformity, not be toxic, expensive and difficult to access. To a greater extent, these requirements are met by hydrocarbons of the paraffinic and naphthenic series, as the most inert and low toxic. CO for checking and adjusting NKP-E devices must also have a specific property - the CO acceleration curves according to GOST 2177-82 must have smooth temperature rises in the areas of the beginning and end of distillation.

Known compositions are CO - calibration mixtures for chromatographs described in [3]. The first mixture is composed of 17 components of the paraffin series from C ₆ to C ₄₄ , the second of 12 components from C ₃ to C ₁₅ and, in addition to n-paraffins, includes isoparaffin and aromatic hydrocarbons.

 The temperatures of the beginning and end of boiling of mixtures and their compositions are not given in [3]. Therefore, to characterize the mixtures, we took the boiling points of the lightest and heaviest components (see Table 1) —the boiling points of the extreme components.

The closest solution to the technical problem, namely, the prototype of the CO compositions is a calibration mixture for calibration and adjustment of chromatographs, are given in [4]. The mixture contains paraffinic, isoparaffinic and aromatic hydrocarbons - a total of 17 components from the hydrocarbon series from C ₅ to C ₁₇ (see table. 1).

 A disadvantage of the known mixture as a composition for tuning and calibrating NKP-E devices is the presence of a large number of components and a wide range of boiling temperatures of the mixture, which reduces the accuracy of tuning and calibration of devices.

 The aim of the invention is to improve the accuracy of tuning and calibration of devices NKP-E in the analysis of fuels for jet engines.

This goal is achieved by the fact that, as CO compositions, mixtures of normal paraffin hydrocarbons are used, taken in the ratio, vol.%: N-octane 10 ... 25 n-nonane 15 ... 30 n-undecane 25 ... 55 n -decane 15 ... 40 n-pentadecane 5 ... 10
The boiling point of the lightest component of the mixture is equal to 126 ^C and very heavy - 271 ° ^C.

 The composition is prepared by mixing the appropriate volumes of these hydrocarbons.

 Examples of CO compositions.

For selection of the composition with an initial boiling point of 135 ... 150 ^C and a final boiling point of 235 ... 250 ^{° C} The following mixture are analyzed.

In example 1, paraffin hydrocarbons are mixed in the ratio: n-octane - 15 vol.%; n-nonana - 15; n-undecane - 50; n-dodecane - 15; and n-pentadecane - 5 vol.%. The resulting mixture has a distillation starting temperature ^of 141 C and a distillation end 242 ^C.

 17 more mixtures were prepared in a similar way and the temperatures of the beginning and end of their distillation were determined. The experimental results are given in table. 2.

Analysis of the data shows that the optimal concentration of hydrocarbons taken to achieve the goal are the ratio, vol. %: n-octane 10 ... 25 n-nonane 15 ... 30 n-undecane 25 ... 55 n-dodecane 15 ... 40 n-pentadecane 5 ... 10
Thus, application of the proposed composition compared to the prototype ensures stability over time CO by reducing the interval between the temperature extreme boiling components from CO 267 ^o C (36 .. .303 ° ^C) to 145 ^{° C (about} 126 ... 271 C) and thereby increase the accuracy of the adjustment of the NKP-E devices to determine the temperatures of the beginning and end of the distillation of jet fuel; use the NKP-E device for express control when regulating the mode of fractionation units; improve the quality of products by reducing fluctuations in its composition; certify laboratories and qualifications of laboratory assistants; significantly simplify the process of producing CO, since there are no gas components with a high melting point; reduce the cost of CO.

Claims (1)

COMPOSITION OF STANDARD SAMPLES FOR TUNING AND VERIFICATION OF EXPRESS TEMPERATURE INSTRUMENTS INSTRUMENTS FOR THE BEGINNING AND END OF LIGHT PETROLEUM PRODUCTS DISTRIBUTION, including normal paraffin hydrocarbons: octane, nonane, undecane and additional accuracy, which also has a different purpose, which makes it more accurate to use n-pentadecane in the following ratio of components, vol.%:
n-Octane - 10 - 25
n-Nonan - 15 - 30
n - Undecan - 25 - 55
n - Dodecan - 15 - 40
n - Pentadecane - 5 -10

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