Method of determining octane number of motor gasolines free of antiknock additives, reforming catalysates, and straight-run gasoline fractions

FIELD: petroleum product investigation methods.

SUBSTANCE: invention relates to methods of investigations and analyses of fuels using standard laboratory equipment and suitable for in-line control of petroleum products' quality. Method of invention comprises determining octane number of reference samples according to research and motor methods, plotting calibration dependence of information parameters on octane number, and subsequent identification of octane number of test sample from this dependence. Information parameters utilized are (i) aromaticity index of tested product represented by proportion of area of a group of peaks for aromatic compounds on express chromatogram of product and (ii)density of product at 20ºC. Octane number of test sample (ON) is calculated from following dependence: ON = ON'+Kn(KaA+675-ρ20), where ON', Kn, and Ka are calibration parameters, A aromaticity index, %, and ρ20 density of sample at 20°C, kg/m3.

EFFECT: simplified and accelerated octane number determination.

9 tbl

 

The invention relates to methods of research or analysis of fuels using standard laboratory equipment and can be used in the oil and gas industry for online quality control of catalization reforming of straight-run fractions not containing antiknock additives trademarks of gasoline.

When used in gasoline engines of various brands main determinant of power and economic performance of the engine is knock resistance of gasoline. The resistance of gasoline to the emergence of detonation combustion depends on its chemical group composition, number in it resistant to detonation compounds and the presence of anti-knock additives.

In practice, the detonation resistance of the fuel appreciate octane numbers (PTS).

Developed and standardized a number of methods for the determination of PTS. In particular, for automotive brands of gasoline used two methods - motor and research, which are different modes of operation of the engine installation to determine the PTS. Estimate simultaneously the two methods gives the possibility to determine the sensitivity of fuel consumption to the mode change. Sensitivity appreciate the difference PTS received research and motor methods [1].

These are the only methods, ODA which separates the antiknock properties of the fuel by direct measurements of the strength of the shock wave in the engine cylinder, owing to what in the world they are standard. However, a significant duration of test (not less than 120 minutes, including warm-up), as well as the high cost of equipment (applies large stationary installation) and reference fuels in some cases make use of a motor and research methods difficult. In particular, this applies to operational quality control of gasoline and its semi-finished products in the stream.

The method for determination of octane number of gasoline, based on the measurement of infrared spectra (IR-spectra, i.e. spectra of electromagnetic radiation with a wavelength of λ>800 nm. When controlling the octane number of complex mixtures containing hydrocarbons and/or substituted hydrocarbons, measure the amount of absorption in the near IR region of the spectrum at the same wavelength in one or more ranges selected from the group consisting of the following ranges: 1572-1698, 1700-1726, 1824-1884, 2058-2130 nm. Perform a mathematical transformation of this signal in the output signal, determining the octane number of the mixture [2].

The main disadvantages of the spectral method is the sensitivity to contamination of the optical path (the turbidity of the sample or the dust of the radiation detector, as a rule, lead to a significant distortion of the result), the high cost of the K-Ochanomizu, as well as the duration and intensity of their calibration as to ensure an acceptable accuracy of the analysis of these devices require selective settings for each type of gasoline, depending on the production technology. Thus, to obtain satisfactory convergence with reference motor units manufacturers IR Ochanomizu it is recommended to have for calibration from 150 to 300 samples for each fuel type (in this case, the calibration is stretched for a few months). In addition, the accuracy of the analysis depends heavily on the composition of the glass used in the manufacture of cups-cuvettes used in the analysis, which, in turn, may necessitate a recalibration of the instrument in case of their replacement.

There is also known a method for determining the octane number of fuels, which serves the air and fuel in a spherical reactor, heated to 280-320°C. After the reaction Grodnoenergo oxidation of octane number is determined by the maximum value of the reaction temperature Grodnoenergo oxidation of the fuel [3].

The disadvantages of the determination of octane number of gasoline by way Grodnoenergo oxidation should be attributed primarily to the fact that in the process of testing is difficult to achieve stable operation and, as a consequence, the determination of the octane number is carried out with the pain of the oops error. In addition, this method also requires the production (or acquisition) of special equipment.

There is a method of determining the PTS of gasoline, including the definition of VERY different reference gasoline engine and the research method, the construction of the calibration according to the information parameter from the PTS and the subsequent identification of PTS analyzed samples on this curve, and as an information option use the dielectric constant, while in the process of measuring the dielectric constant of the sample additionally measure the current value of temperature and density, and PTS of the sample is determined by the following dependencies:

PTS=a1·ε2-a2·ε3+a3·ε+b·ρ+·T;

where a1;2;3; b; C - constant coefficients determined during calibration;

ε - the measured value of dielectric permittivity;

ρ - the measured value density, g/cm3;

T is the measured temperature value, °C.

The disadvantages of this method, taken as a prototype should be used as the main characteristics of PTS gasoline only permittivity εthat reduces the accuracy PTS in the study of ensinou with different chemical admixtures.

In addition, devices are required, self-calibration which the user is not allowed [4].

There is also described a method for determination of octane number, which in addition to the dielectric permittivity ε it also takes into account the magnetic permeability μ gasoline. This information is used by the resonant frequency of the oscillating circuit, the capacitance elements and inductance of which is placed the sample analyzed gasoline [5].

This method also requires the manufacture of special equipment, its accuracy is relatively small.

Object of the invention is the creation of an effective measurement technology that does not require the use of special equipment and it is quite accurate and fast. When this task was to provide an analysis of how commodity gasoline, and various semi-finished products (straight-run gasoline fractions and catalization reforming).

The problem is solved in that in the method for determining the octane number of gasoline, including the definition of VERY different reference samples by motor and research methods, preparation of calibration according to the information parameter from the PTS and the subsequent identification of PTS analyzed samples for this dependence, according to the invention is as an information options use the percentage of the total group of peaks of aromatic compounds on the chromatogram of gasoline or semi-finished product, hereinafter referred to as the index of aromaticity, and the density of the sample at standard temperature, which in parallel with the chromatographic determination of the aromaticity index measuring the current value of the density and temperature of the sample, then the standard tables [6] give density to the temperature of 20°and PTS of the sample is determined according to the following dependence

where PTS - octane, % PTS;

A - index of aromaticity, %;

ρ20the density of the sample at 20°C, kg/m3;

675 - arbitrary conditional density, kg/m3;

PTS', KP, Ka - constant values determined during calibration.

The physical meaning of the value of PTS' is what the octane rating is a hypothetical dearomatizing (A=0) a substrate of a particular type of gasoline with 20°With the density of 675 kg/m3. With this great amount of PTS', as a rule, the greater the degree of isomerization of alkanes in gasoline.

New in relation to the prototype is that as an information parameter instead of the dielectric constant used for characterizing the total content of aromatic hydrocarbons index of aromaticity is a parameter which can easily be detected by standard laboratory gas chromatograph with a high degree of accuracy that poses the s thereby significantly improve the accuracy of analysis in General, approaching this indicator to the IR Octanorm. However, unlike the latter to build an adequate mathematical model in this case, only a 10-15 samples lying in the range of 4-5% PTS. Processing the calibration data is performed with the use of the criterion of minimizing the sum of squared deviations from the reference values of the PTS of samples defined on the engine installations.

theoretical basis of the proposed method for determination of octane number was known relationship between octane number and content of aromatic compounds (which definitely increase the PTS of gasoline), and the fact that linear low-octane hydrocarbons, non-aromatic substrate gasoline generally have a higher density than their high-octane isomers.

During several hundreds of tests of various samples of gasoline and gasoline fractions (list types of samples are shown in table 1) was experimentally found that for the same total content of aromatic hydrocarbons more detonation resistance always shows a sample whose density at the same temperature less. This was the basis for the creation of a mathematical model that simultaneously takes into account both the total content of aromatics in gasoline, and its standard density

Example.

Instrumentation and procedure definition looks as follows:

- The index of aromaticity is carried out on a standard gas chromatograph with thermal conductivity detector or a flame ionization (the author used chromatograph type 3700, manufactured by the factory "Chromatograph", Moscow). Condition analysis: column - length 3 m, inner diameter 2 mm, the nozzle 30% of nitrilimines OV-275 on Chromatone P-AW, the flow of carrier gas 25-30 cm3/min, column temperature 200-230°C (isothermal mode), the temperature of the evaporator 250°S, sample (in the amount of 0.5-1 µl) was injected into the chromatograph evaporator by microspace. The resulting under these conditions, the chromatogram is a sequence of peaks, consisting of a narrow peak nah3-C12followed by compact groups of peaks of aromatic hydrocarbons, almost merged into one peak. The chromatogram is processed by the normalization method using an integrator or paired with a chromatograph of a personal computer (if the method used integrator Ingram-1M", manufactured NGO Hemelektronik", Moscow). An important condition for the convergence of the results is the rule of constant interpretation of all possible peaks of aromatic connected to the th as a single group of peaks. The analysis time 2-3 minutes

- Determination of the density and temperature of the sample is performed by dipping in a glass cylinder with a sample standard laboratory hydrometer for petroleum products type of ANT (or similar) with a built-in his case a thermometer.

On the basis of the test results was generated database of calibration dependences presented in table 1. The results of comparative tests (as a control we used the results obtained for universal single cylinder installations type FMP-85 configured on the motor (GOST 511) and research (GOST 8226) method) are presented in table 2-9.

Conducted research and presented in the tables, the results allow to draw conclusions.

1. Proven reliable and rapid determination of octane number using nonspecific standard analytical equipment, serial industry and available to any laboratory of petroleum products.

2. This regularity, with the same value of the index of aromaticity higher octane number has the same type of gasoline with a lower standard density. This allows you to create gauge dependence I=f(A, ρ20).

3. Calibration takes relatively little time and does not involve any technical difficulties because it requires the calculation of all three calibration parameters (PTS', ToandTop).

4. High stability of measurement results and a small error in the determination of PTS.

5. Total time identify PTS at the heated apparatus does not exceed 3 minutes, which makes possible the use of the method for operational monitoring of technological processes and product quality.

The method is new, because we don't know the technical solutions of the patent and scientific research information (in addition to the above in the application materials analogues and prototypes), in which was represented the totality of distinctive features set forth in the claims (mathematical dependence, reflecting the relationship of measured parameters and ρ20and the control that is used as a database - PTS).

The proposed solution involves an inventive step, since the indicator PTS equivalent combination of aromaticity index and density of the sample ρ at a certain temperature, for any specialist in this field is not obvious from the prior art, and requires research to identify the relationship and correlation parameters of PTS', KaTop.

The method is industrially applicable, has been successfully tested in the laboratory production control Sosnogorsk GPP 000 "Severgazprom"./p>

SOURCES of INFORMATION

1. Pokrovsky G.P. Fuel, lubricants and coolants. - M.: Mashinostroenie, 1985, p.35-37.

2. U.S. patent No. 5349188, CL G 01 N 21/35.

3. Autospid. The USSR №1245975, CL G 01 N 25/20, 1983.

4. RF patent №2100803, CL G 01 N 27/22, 33/22, 1997.

5. RF patent №2196321, CL G 01 N 27/22, 2000.

6. GOST 3900-85 Oil and petroleum products. Methods of determination of density".

Table 1
FuelFactoryProduction technologyCalibration rangePTS'ToAndToP
PTSAndρ20
A. Motor method
A-zSGPSZeoforming, compounding73-8011-20676-69963,54,190,275
A-lSGPSZeoforming72-8121-33721-75263,84,080,270
A-76, AI-92UnpsThe platforming, compounding76-8427-54 717-77063,92,370,562
pramosonevariousRectification, separation47-780-12630-73062,30,980,346
B. Research method
AI-80SGPSZeoforming, compounding75-8813-37686-75666,04,570,240
A-zSGPSZeoforming, compounding76-8112-20685-71062,5to 4.410,336
A-lSGPSZeoforming77-8521-29726-74267,54,150,275
A-76, AI-92UnpsThe platforming, compounding81-9430-54721-77057,02,800,630
Manufacturers:

SGPS - Sosnogorsk gas processing plant (OOO Severgazprom")

Unps - Ukhta refinery (LUKOIL-Ukhta)

/tr>
Table 2
№ p/pAndρ20kg/m3Octane numberDivergence
according to GOST 511according to the claimed method
123456
111,14676,376,176,0-0,1
211,22680,274,575,0+0,5
311,68690,173,272,8-0,4
4a 12.03686,973,674,1+0,5
512,06682,3to 75.275,4+0,2
612,51681,976,076,00
712,92682,376,676,4-0,2
813,12684,076,376,1-0,2
913,16683,076,476,5+0,1
10of 13.18679,677,477,40
1113,20687,875,4to 75.2-0,2
1213,23687,575,675,3-0,3
1313,28685,975,675,8+0,2
1413,40685,276,276,1-0,1
1513,40682,7of 76.8of 76.80
1613,44to 680.677,277,0+0,2
1713,46683,076,4of 76.8+0,4
1813,51681,477,577,3-0,2
1913,51680,777,777,5-0,2
20of 13.58691,574,574,6+0,1
2113,68685,376,676,4-0,2
2213,71682,577,0 77,2+0,2
2313,73684,176,7of 76.8+0,1
2413,76684,277,1of 76.8-0,3
2513,89687,576,276,1-0,1
2613,93683,577,477,2-0,2
2714,14686,976,976,5-0,4
2814,19689,075,976,0+0,1
2914,22689,175,876,0+0,2
3014,27685,8of 76.877,0+0,2
3114,29689,876,175,9-0,2
3214,34687,176,376,7+0,4
3314,35688,576,376,30
3414,40686,077,077,1+0,1
1 23456
3514,44689,476,276,20
36accounted for 14.45691,275,675,7+0,1
37accounted for 14.45687,576,776,70
3814, 48mm687,177,076,9-0,1
3914, 48mm688,476,376,5+0,2
4014,49686,877,077,00
4114,58688,8of 76.876,5-0,3
4214,65690,076,476,3-0,1
4314,79692,175,875,80
44the 14.90692,076,376,0-0,3
45the 14.90690,076,976,5-0,4
4615,01689,776,5of 76.8+0,3
4715,07690,876,576,50
4815,25692,376,176,3+0,2
4915,38693,476,476,2-0,2
5015,59694,376,376,2-0,1
5116,06692,877,277,1-0,1
5216,49696,376,476,6+0,2
5316,59699,076,276,0-0,2
5416,85692,877,978,0+0,1
5517,25693,078,278,4+0,2
5619,70696,880,4an 80.2-0,2

tr>
Table 3
№ p/pAndρ20kg/m3Octane numberDivergence
according to GOST 511according to the claimed method
123456
1to 20.88732,271,971,3and-0.6
221,49729,972,972,7-0,2
321,74726,074,474,0-0,4
421,96721,476,575,5of-1.0
522,29729,673,973,6-0,3
622,45732,073,273,1-0,1
722,60723,3to 75.275,7+0,5
8cushion 22.66726,874,674,8+0,2
922,68732,473,573,3-0,2
1022,99729,174,374,5+0,2
1122,99729,374,974,5-0,4
1223,21731,074,274,20
1323,25731,174,474,3-0,1
1423,28us 726.275,775,6-0,1
1523,46725,776,376,0-0,3
1623,53725,776,476,0-0,4
1723,63725,676,676,2-0,4
1823,65729,575,875,1a-0.7
1923,92728,474,875,7+0,9
2023,97726,975,976,2+0,3
2124,05727,276,376,2-0,1
2224,41730,676,075,7-0,3
23of 24.90730,375,476,3+0,9
2424,95734,974,7 75,1+0,4
2525,20735,674,9to 75.2+0,3
2625,36725,777,878,0+0,2
2725,45733,776,476,0-0,4
2825,75729,577,577,50
2925,87734,975,876,1+0,3
3025,99735,075,676,2+0,6
3126,20734,975,376,5+1,2
3226,39737,076,076,1+0,1
3326,48728,978,478,40
3426,78743,273,874,9+1,1
3526,85727,279,479,3-0,1
3628,20730,979,579,8+0,3
37of 28.96 742,477,477,5+0,1
3832,72752,180,779,0-1,7

Table 4
№ p/pBrand gasolineAndρ20kg/m3Octane numberDivergence
according to GOST 511according to the claimed method
1A-7627,24716,776,976,7-0,2
2A-7630,29722,877,577,4-0,1
3A-7632,31726,777,877,9+0,1
4A-7635,67737,376,176,4+0,3
5AI-9249,60756,383,984,3+0,4
6AI-9251,27762,283,783,2-0,5
7AI-9254,3 769,882,683,0+0,4

Table 5
№ p/pAndρ20kg/m3Octane numberDivergence
according to GOST 511according to the claimed method
10,04630,377,677,5-0,1
20,81638,274,875,0+0,2
31,42642,272,473,8+1,4
4of 3.64703,953,353,2-0,1
55,49676,664,763,3of-1.4
6of 5.92672,665,664,8-0,8
75,97682,961,561,3-0,2
811,33725,647,448,3+0,9
9a 12.03729,5to 47.2 to 47.20

For reference:

a valid difference between the two installations according to GOST 511 (motor method) to 1.6% PTS

Table 6
№ p/pAndρ20kg/m3Octane numberDivergence
according to GOST 8226according to the claimed method
123456
112,72685,677,877,4-0,4
2of 13.58701,474,574,6+0,1
317,65721,374,674,2-0,4
418,18698,680,680,3-0,3
518,43700,680,580,1-0,4
619,46704,280,380,30
719,60708,778,779,4+0,7
8 to 19.74697,681,582,2+0,7
919,84704,480,980,7-0,2
10fall of 19.88707,380,180,10
1120,19712,079,979,3and-0.6
12to 20.52707,680,780,70
1320,76706,581,581,2-0,3
1420,80709,480,880,6-0,2
1520,82706,681,181,3+0,2
1621,00710,680,480,5+0,1
1721,06706,281,981,6-0,3
1821,08706,781,581,50
19to 21.15711,080,780,6-0,1
2021,66to 713.380,480,6 +0,2
2121,79714,9an 80.280,3+0,1
2222,18714,880,480,8+0,4
2322,22714,981,580,8a-0.7
2423,80720,481,381,2-0,1
2524,26718,781,982,1+0,2
2624,42718,382,282,4+0,2
2725,47722,582,382,5+0,2
2826,61720,783,784,2+0,5
2927,33734,982,381,6a-0.7
3027,52734,282,682,6and-0.6
3128,42738,382,282,0-0,2
3228,64737,682,382,4+0,1
3328,79739,7 82,182,0-0,1
3429,17741,282,082,1+0,1
3529,29738,482,982,90
3629,53740,983,082,6-0,4
3729,57742,082,782,4-0,3
3830,08746,581,381,8+0,5

123456
3930.20mm744,081,782,6+0,9
4030,31744,181,982,7+0,8
4130,31744,0of 83.482,7a-0.7
4230,52 to 739.0is 83.884,1+0,3
4330,53741,283,683,60
4430,61742,4is 83.8of 83.4-0,4
4530,71739,884,484,1-0,3
4632,07745,783,784,2+0,5
4733,31745,784,985,6+0,7
4833,64749,286,085,1-0,9
4933,76752,8to 83.584,4+0,9
5035,30750,887,2 86,5a-0.7
5136,67752,088,087,7-0,3
5236,96756,586,8of 87.0+0,2
Table 7
№ p/pAndρ20kg/m3Octane numberDivergence
According to GOST 8226according to the claimed method
123456
1a 12.03686,975,776,3+0,6
213,40685,278,978,90
3accounted for 14.45687,579,779,70
4accounted for 14.45691,278,578,50
5the 14.90690,080,079,5-0,5
615,06693,678,878,6-0,2
715,73695,879,578,8a-0.7
816,56695,679,880,1+0,3
916,73700,978,678,60
1016,85692,881,181,5+0,4
1120,18709,880,580,7+0,2

Table 8
№ p/pAndρ20kg/m3Octane numberDivergence
according to GOST 8226according to the claimed method
121,49729,977,576,9and-0.6
221,74726,078,4to 78.3-0,1
322,99729,178,978,90
423,21731,0to 78.378,6+0,3
523,97726,980,580,6+0,1
624,83734,679,179,4+0,3
7 25,36725,782,282,5+0,3
826,20734,980,180,9+0,8
926,48728,982,882,9+0,1
1026,85727,284,2is 83.8-0,4
1128,20730,984,584,3-0,2
12of 28.96742,482,582,0-0,5
Table 9
№ p/pBrand gasolineAndρ20kg/m3Octane numberDivergence
according to GOST 8226according to the claimed method
1 A-7629,77720,580,980,8-0,1
2A-7635,67737,380,780,70
3AI-9249,60756,293,593,3-0,2
4AI-9251,27762,2for 93.492,5-0,9
5AI-9254,33769,892,2br93.1+0,9

For reference:

a valid difference between the two installations according to GOST 8226 (research method) to 1.0% PTS

The method for determining the octane number (PTS) not containing antiknock gasoline additives, catalization reforming and straight-run gasoline fractions, including the definition of VERY different reference samples motor and research methods, preparation of calibration according to the information parameters from the PTS and the subsequent identification of PTS analyzed samples for this C the dependence, characterized in that the quality of the information parameters use the index of aromaticity of the analyzed product, representing a percentage of the total group of peaks of aromatic compounds on its Express chromatogram, and its density at 20°and PTS of the sample is determined by the following dependencies:

PTS=PTS'+Kp×(Kand×A+675-ρ20),

where PTS', Kpand Kand- constant values determined during calibration;

A - index of aromaticity, %;

ρ20the density of the sample at 20°C, kg/m3.



 

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15 dwg, 1 tbl, 15 ex

FIELD: investigating or analyzing materials.

SUBSTANCE: method comprises determining the values of the inform-parameter for various reference petrols, plotting calibration dependence of the inform-parameter on the octane number, determining the value of the inform-parameter of a sample of petrol to be analyzed, determining octane number of the petrol to be analyzed from the calibration curve, and measuring density and temperature of the sample. The value of the inform-parameter is determined from measuring the surface tension of the sample. The octane number is calculated within temperature range 10-40oC.

EFFECT: enhanced accuracy of determining.

1 tbl cl, dwg

The invention relates to the measurement technique is to measure the water content in oil-water emulsions and can be used in automation of processes of extraction and refining, as well as during metering operations

The invention relates to the field of measuring equipment

FIELD: analytical methods.

SUBSTANCE: method is recommended for identification of following aromatic hydroxysulfonic acids when analyzing azo dye production effluents: 2-naphthol-6-sulfonic acid, 1-naphthol-3,8-disulfonic acid, 2-naphthol-6,8-disulfonic acid, 1-amino-2-naphthol-4-sulfonic acid, 1-amino-8-naphthol-3,6-disulfonic acid, and 5-aminoculfosalicylic acid. Analytical procedure: ammonium sulfate is preliminary added to an aqueous solution until saturation and resulting solution is extracted with equimolar acetone-diacetone alcohol mixture at extractant-to-sample volume ratio 1:10. Extract is then analyzed with the aid of radial paper chromatography technique using as mobile phase acetone/diacetone alcohol/water mixture at volume ratio (0.9-1.1):(0.9-1.1):0.5.

EFFECT: enabled identification of different aromatic hydroxysulfonic acids when simultaneously present in solution.

2 tbl, 16 ex

FIELD: chromatographic sorbents.

SUBSTANCE: invention relates to chromatographic sorbents, which can be used for analysis and preparative purification of optically active compounds. A novel sorbent for resolution of isomers of optically active compounds is developed containing, as chiral selector, macrocyclic glycopeptide antibiotic eremomycin, vancomycin, ristomycin A, teicoplanine, or their aglycons. Method of immobilization of macrocyclic glycopeptide antibiotics is also developed, which resides in that silica gel in aqueous buffer solution is first treated with 3-glycidoxypropyl(trialkoxy)silane and then, in alkaline aqueous or water-organic solution, above-indicated macrocyclic glycopeptide antibiotic is grafted to epoxy group-modified silica gel.

EFFECT: increased selectivity in enantiomer resolution and simplified preparation procedure.

9 cl, 12 dwg, 5 tbl, 9 ex

FIELD: chemical industry.

SUBSTANCE: during process of taking sample from technological pipe-line, absorption of water vapors and nitrogen oxides (II) and (IV) are conducted simultaneously. For the purpose the chemical agents are used which don't absorb nitrogen oxide and don't react with it. Chromatographic measurement of volume fraction of nitrogen oxide (I) is carried out by means of industrial chromatograph having heat-conductance detector by using column of thickness of 5 m and diameter of 3 mm. The column is filled with polysorbent; temperature of column's thermostat is 20-30 C and temperature of evaporator is 100C. Hydrogen is used as a gas-carrier. Concentrations of nitrogen oxide, measured by the method, belong to range of 0, 05-0, 50% of volume fraction. Method excludes aggressive affect of corrosion-active components on sensitive parts of chromatograph. Method can be used under industrial conditions for revealing factors influencing process of forming of nitrogen oxide at the stage of catalytic oxidation of ammonia and searching for optimal conditions for minimizing effluent of ammonia into atmosphere.

EFFECT: high reproduction; simplification; improved efficiency of operation.

3 ex

FIELD: analytical methods.

SUBSTANCE: invention discloses method for preparation of pectin extract and can be used in production of pectin (for determining pectin substances in raw material). Method comprises triple extraction of pectin hydrates with water at 40°C followed by extraction of protopectins first with 0.3 N aqueous hydrochloric acid at 100°C and then with 1% aqueous ammonium citrate solution at 100°C. Novelty resides in preliminary treatment of vegetable stock with tenfold excess of 9.7% aqueous sodium bicarbonate solution at stirring by mechanic stirrer at 100 rpm at ambient temperature during 193 min followed by washing with tenfold excess of distilled water at ambient temperature.

EFFECT: facilitated pectin production control.

1 tbl

FIELD: gas chromatography.

SUBSTANCE: detector has case. Burner provided with channels for supplying oxygen and air is disposed inside the case together with central channel for supplying sample inside gas-carrier. Condenser, lens, disc with interference light filters, glued prism with reflecting interference coatings, radiation receiver are mounted in series inside the case.

EFFECT: improved sensitivity; higher selectivity of detector.

2 cl, 2 dwg

FIELD: analytical chemistry, ecology, in particular controlling of environmental air.

SUBSTANCE: claimed method includes aspiration if air sample through chemosorbtive medium, elution of formed dimethylamine salt, eluate closure with alkali, and gas chromatography analysis of gas phase with flame-ionization detection. Dimethylamine salt elution from adsorbent is carried out with 1 cm3 of distillated water; closured with alkali eluate is held in thermostat for 5 min; and as filling in separating chromatography column chromosorb 103, containing 5 % of PEG-20000 and treated with 20 % hexamethyldisilazane solution is used.

EFFECT: method for dimethylamine detection with improved sensibility and accuracy.

FIELD: analytical chemistry, ecology, in particular controlling of environmental air.

SUBSTANCE: claimed method includes aspiration if air sample through chemosorbtive medium, elution of formed dimethylamine salt, eluate closure with alkali, and gas chromatography analysis of gas phase with flame-ionization detection. Dimethylamine salt elution from adsorbent is carried out with 1 cm3 of distillated water; closured with alkali eluate is held in thermostat for 5 min; and as filling in separating chromatography column chromosorb 103, containing 5 % of PEG-20000 and treated with 20 % hexamethyldisilazane solution is used.

EFFECT: method for dimethylamine detection with improved sensibility and accuracy.

FIELD: investigating or analyzing materials.

SUBSTANCE: method comprises supplying of batched volumes of oil sample, standard material for comparison, and n-heptane by displacing them by the gas flow to the capillary column for chromatography. The pressure in the gas flow is higher than that at the inlet of the column. The device comprises batching cock, check valve in the gas line, and resistance in the line for discharging the gas. The valving members are made of pipes with plugs at the center and are interconnected through a gas cross-piece and vessel for batching the gas.

EFFECT: enhanced accuracy of determining hydrocarbons.

2 cl, 1 dwg, 1 tbl

FIELD: medicine, biochemistry.

SUBSTANCE: at testing one should precipitate high-molecular compounds with acetonitrile and register supernatant's spectral characteristics. Supernatant should be applied onto a paper filter, dried and put into solution containing aromatic aldehyde, acetone and concentrated hydrochloric acid taken at weight ratio of 70:5:1 to be kept for 2-3 min. Then it should be once again dried up to detect qualitative and semiquantitative content of oxidized tryptophan metabolites by intensity and chromatic shades. Moreover, by chromatic shades of yellow dyeing it is possible to detect the content of hydroxylated metabolites and by chromatic shades of violet dyeing - that of unhydroxylated ones.

EFFECT: higher significance of detection.

3 ex

FIELD: instrument industry.

SUBSTANCE: detector comprises housing which is the cathode of the detector, devices for supplying and discharging gas to be analyzed, anode, tritium target, and insulator housed in the space between the electrodes. The working surfaces of the electrodes are parallel and mounted with a spaced relation to each other with the use of the insulator. The detector is provided with current lead and current collectors. The insulator is made of a ring made of silicate-containing material and is interposed between the electrodes.

EFFECT: enhanced stability of operation and prolonged service life.

2 cl, 1 dwg

FIELD: analytical instrumentation engineering; chromatographic analysis of composition of substances.

SUBSTANCE: proposed method includes delivery of carrier gas to evaporation chamber through gas supply line, introduction of sample into evaporation chamber, delivery of part of gas flow from evaporation chamber to chromatographic column and discharge of remaining of gas flow to atmosphere. Delivery of carrier gas to evaporation chamber is effected in direction opposite to motion of evaporated sample to chromatographic column. Device proposed for introducing the sample into chromatograph has sample introducing line, evaporation chamber, chromatographic column, carrier gas supply and carrier gas discharge line which are connected with evaporation chamber. Carrier gas discharge line is connected with evaporation chamber in area of introduction of sample and carrier gas supply line is connected with opposite end of evaporation chamber.

EFFECT: enhanced accuracy of dosing the sample; improved quality of separation of components; enhanced reliability; simplified construction.

11 cl, 3 dwg

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