RU2745752C1 - Sampling devices of continuous and cyclic type and method for detecting mixture components using sampling devices - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to sampling in chemistry, as well as to analytical chemistry equipment, and can be used for the rapid detection of components, as well as for the quantitative and qualitative determination of the content of individual organochlorine compounds, sulfur-containing compounds, formaldehyde in oil, naphtha, kerosene, gas oil, diesel fuel, naphtha fraction, fuel oil, gasoline, complex hydrocarbon mixtures, chemical reagents using a laboratory or industrial chromatograph analyzer by the method of equilibrium vapor analysis in cyclic and continuous modes. The proposed method for detecting the content of individual organochlorine and sulfur-containing components of a hydrocarbon mixture by chromatographic analysis of steam includes taking a sample of equilibrium steam and supplying steam through a pipeline or a nebulizer to a continuous or cyclic sampling device with a compressor in the form of a finely dispersed gas-liquid fraction at a rate of not more than 1000 ml / min, heating the sampling device to 20-150°С for no more than 60 min, ensuring the transition of the analyzed components to the vapor phase accumulating in the upper part of the sampler, while for more efficient extraction of the determined components into the vapor phase, bubbling is carried out with a heated inert gas, and after reaching the phase equilibrium, the transfer of equilibrium steam from the sampler is provided by opening the valve from the sampler into the dosing loop of the analyzer / chromatograph dosing valve through the supply line (with or without heating), and the loop is made with a volume from 10 μl to 5 ml, then dosing is carried out into the chromatographic guard column to separate interfering components-impurities, and the target components are sent to the next main analytical chromatographic column, where they are separated at a temperature of 50-350 ° C and registered with a detector, and the liquid part of the oil products is discharged through the drain located in the lower part of the sampling device, while the filling level of the sampling device is ensured using a level gauge or by the pressure value. Also proposed is a sampling device for extracting equilibrium vapor of continuous and cyclic type.

EFFECT: technical result of the claimed invention consists in the possibility of increasing the degree of extraction of components into the vapor phase with obtaining high sensitivity and precision of the method, reducing the analysis time, achieving a high degree of automation of the analysis, the possibility of using digital technologies, a wide range of analyzed components, simplifying the process of calibrating the chromatograph.

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Description

The invention relates to sampling devices for analytical chemistry, and can be used for the rapid detection of components, as well as for the quantitative and qualitative determination of the content of individual organochlorine compounds, sulfur-containing compounds, formaldehyde in oil, naphtha, kerosene, gas oil, diesel fuel, naphtha fraction, fuel oil , gasoline, complex hydrocarbon mixtures, chemical reagents using an analyzer (laboratory and / or industrial chromatograph) by the method of equilibrium vapor analysis in cyclic and continuous modes.

In the article Investigation of volatile components of petroleum products at oil and gas facilities by the method of equilibrium steam analysis, M.A. Galishev. and other scientific and analytical journal "Bulletin of the St. Petersburg University of the State Fire Service of the EMERCOM of Russia" 2017, the design of the installation for the analysis of the equilibrium steam of the circulation type is proposed, and experiments are described on the study of volatile components of petroleum products by the method of analysis of equilibrium steam with combined IR spectroscopic and gas chromatographic determination. The proposed technique makes it possible to establish the presence and carry out diagnostics of petroleum products and organic solvents of various compositions, having low boiling points and high saturated vapor pressures.

In patent RU 2219541 G01N 1/10 2003, the determination by gas chromatography of the quantitative and individual composition of volatile organochlorine compounds in crude oil, petroleum products, chemical reagents of the oil-producing and oil-refining industries is described. The method is based on the fact that the analyzed mixture is passed in a carrier gas flow through an evaporator at 220-350 ° C, then separated in a capillary column of a chromatograph at 50-320 ° C, detected at 220-350 ° C in an electron-capture detector, in which additionally a carrier gas is supplied at a rate of 20 cm ³ / min, and a specific source of pollution is established by the quantitative and individual composition of volatile organochlorine compounds.

From patent RU 2545087, G01N 1/102015, a method is known for the determination of organochlorine in natural and waste waters and using gas chromatography, using headspace analysis, which includes the determination of chlorobenzene on a capillary chromatographic column in a carrier gas stream representing nitrogen; formation and registration by the flame ionization detector of the investigated ions formed in the flame. At the same time, a basic solution is prepared using a more viscous solvent ethylene glycol, therefore the basic solution is well preserved for 2 months at a temperature from -2 ° C to -10 ° C. Then prepare calibration solutions for the concentration range of chlorobenzene 0.0003-0.02 mg / dm ³ . Next, sample preparation is performed, the chromatograph is calibrated by piercing the vapor phase of the prepared concentrations, a calibration graph is built, sample preparation is performed for the water samples under study, the vapor phase is pierced into the chromatograph evaporator. In this case, the data obtained are processed with the ChemStation computer program, which is supplied with the MAESTRO 7820A chromatographic complex, and a qualitative identification and quantitative content of the analyte is obtained.

From the prior art (Direct determination of the total content of chlorine and sulfur-containing organic impurities in water, EA Syrbu et al., Bulletin of Moscow University. Ser. 2. Chemistry. 1998. T. 39. No. 5) known method direct determination of the total content of chlorine and sulfur-containing organic compounds in water along with inorganic impurities, based on a combination of high-temperature conversion of these compounds in an oxygen atmosphere, followed by their ion chromatographic determination.

As the closest technical solution, the technical solution RU 114533 G01N 1/00, 2012 was chosen, which describes a device that provides sampling of the equilibrium vapor phase from the liquid phase with an increased degree of concentration of light sulfurous gases in the sample being taken with a constant flow of the liquid phase through the sampler and preservation of the immobility of the gas phase, simple in design, reliable in operation, providing selection and supply to the chromatograph for analysis of the equilibrium vapor phase of oil in automatic mode due to a vapor-phase flow-through sampler containing a body, a pipeline for supplying the analyzed oil, a pipeline for removing the vapor phase for analysis, when In this case, the housing is additionally equipped with a control and safety drain and an operational drain, on which an electromagnetic valve is installed, inside the housing, a sampling chamber is additionally installed in the form of a hollow cylinder without a bottom, to the upper part of which a vapor phase removal pipeline is connected, with the lower edge of the sampling chamber is located above the bottom of the housing and below the opening of the operational drain, and a reflector is installed inside the sampling chamber, under which the analyzed oil supply pipeline is vertically connected; The sampler body is equipped with heaters and temperature sensors.

The disadvantages of all the above solutions are the low detection limit of the components, and only manual control of the process is allowed, the identification of a too narrow range of individual components.

In addition, the disadvantage of analogs is that the devices provide sampling of the equilibrium vapor phase from oil of light sulfurous gases with a constant flow of the liquid phase of the oil through the sampler and maintaining the immobility of the gas phase, which does not meet the requirements of the laws of vapor phase analysis.

The objective of the claimed invention is to develop a sampling system that eliminates the error in manual sampling, the influence of the human factor on the impartiality of the analysis, and allows you to implement the "digital" metrology of the method - automatically check the correctness of the device and the reliability of measurements by comparing the obtained metrological characteristics of the analysis of a real sample with those included in the program, thereby identifying deviations in the operation of the device and measurements. This will allow increasing the reliability of measurements, planning repair work in advance, checking the device remotely and introducing certification of products “without a laboratory assistant”.

The technical result of the claimed invention is to increase the degree of extraction of components into the vapor phase, reduce the analysis time, achieve a high degree of analysis automation, the possibility of using digital technologies, increase the list of analyzed components, and simplify the chromatograph calibration process.

The claimed technical result is achieved due to the claimed method, as well as the use of sampling devices for extracting equilibrium steam of continuous type and cyclic type.

A method is proposed for detecting the content of individual organochlorine and sulfur-containing components of a hydrocarbon mixture by chromatographic analysis of steam, including taking a sample of equilibrium steam and supplying steam through a pipeline or a nebulizer to a continuous or cyclic sampling device with a compressor in the form of a finely dispersed gas-liquid fraction at a rate of not more than 1000 ml / min. heating the sampling device to 20-150 ° C for no more than 60 minutes, ensuring the transition of the analyzed components to the vapor phase accumulating in the upper part of the sampler, while for more efficient extraction of the determined components into the vapor phase, bubbling is carried out with a heated inert gas, and after reaching phase equilibrium, the transfer of equilibrium steam from the sampler is ensured by opening the valve from the sampler into the dosing loop of the analyzer / chromatograph dosing valve through the supply line (with or without heating), moreover, the flow loop filled with a volume of 10 μl to 5 ml, then dosing into a chromatographic pre-column to separate interfering components-impurities, and the target components are sent to the next main analytical chromatographic column, where they are separated at a temperature of 50-350 ° C, and registered with a detector, and the liquid part of oil products is discharged through a drain located at the bottom of the sampling device.

Dosing of the sample is carried out by pneumatic method of dosing according to the pressure drop, the known sample volume, given by the pressure difference in the sampler and in front of the column.

The method can be applied to an analyzer, laboratory gas chromatograph, flow chromatograph or chromatomass spectrometer.

The analyzed mixture is oil, naphtha, kerosene, gas oil, diesel fuel, naphtha fraction, fuel oil, gasoline, complex hydrocarbon mixtures, chemical reagents.

Also, a sampling device for extracting equilibrium steam of a continuous type is proposed for a method for detecting the content of individual components of a mixture, including a sampler with a sampling compressor, a pressure regulator in a sulfinert design and a rotameter, in the center of the sampler there is a sulfinert sampling chamber for supplying a sample in the form of a finely dispersed gas-liquid fraction through a pipeline or nebulizer, while the device is equipped with a heated / unheated steam supply line - a heated pipeline with a chromatograph / analyzer dosing valve made with a dosing loop with a volume of 10 μl to 5 ml, and filters to prevent residual liquid aerosol and mechanical impurities from entering the sample supply line installed in front of the chromatograph / analyzer.

In addition, a sampling device for extracting equilibrium steam of a cyclic type is proposed for a method for detecting the content of individual components of a mixture, including a sampling device with a volume of 0.11 - 4 liters, a sampling compressor with a pressure regulator in sulfinert design, a nebulizer and a rotameter, and to achieve a predetermined level of steam / liquid the device is equipped with a level gauge and a shut-off valve, the analyzer is made with a dosing valve with a dosing loop, with a volume of 10 μl to 5 ml, the device has a heated pipeline - a supply line, is made with the provision of bubbling with heated gas, and is equipped with a pressure sensor with a valve for transfer equilibrium steam from the sampling device into the dosing loop of the dosing valve of the analyzer along the heated supply line, filters are installed in front of the analyzer, and in the lower part of the sampling device there is a drain for the liquid phase and an emergency drain, preventing the ingress of the liquid part of the sample into the analyzer, and safety valve, which is triggered at an overpressure of more than 3 kg / cm2, to ensure the possibility of repeating the next cycle of steam extraction after the removal of the residues and express detection of the content of individual components of the mixture. The device is equipped with a level gauge to ensure the fill level of the sampler.

The invention is illustrated in the drawings.

Figure 1 shows a continuous type headspace vapor recovery sampling device, and figure 2 shows a cyclic type headspace vapor recovery sampling device where:

1 - pipeline,

2 - sampling compressor,

3 - sulfinert pressure regulator,

4 - rotameter,

5 - heated sampling device,

6 - sulfinert sampling chamber,

7 - spray,

8 - dosing loop of the dosing tap,

9 - heated supply line,

10 - coalescent filter

11 - shut-off valve

12 - rotameter

13 - shut-off valve

14 - pressure regulator

15 - shut-off valve

16 - stock,

17 - level gauge,

18 - safety valve,

19 - pressure sensor,

20 - temperature sensor,

21 - analytical column,

22 - detector.

The work of the sampling device for extracting equilibrium steam of a continuous type is carried out according to the following principle. A sample of oil through the heated pipeline 1 through the sampling compressor 2 enters the pressure regulator 3 in sulfinert design, where it is reduced and with a fixed flow rate through the rotameter 4 enters the heated sampling device 5. In the center of the sampling device there is a sulfinert sampling chamber 6, into which the sample enters through atomizer 7, in the form of a finely dispersed gas-liquid fraction.

The sampling device is heated in the temperature range from 20 to 150 C, at which organochlorine, sulfur-containing compounds, formaldehyde pass from the liquid phase to the vapor, which accumulates in the upper part of the sampler. The sampler is equipped with a heated inert gas bubbling for efficient extraction of the measured components into the vapor phase.

The transfer of equilibrium steam from the sampler to the dosing loop of the dosing valve 8 of the analyzer / chromatograph occurs through the heated supply line 9. The dosing loop has a volume of 100 μl to 5 ml, where quantitative and qualitative analysis takes place. To prevent residual liquid aerosol from entering the sample supply line, a coalescence filter 10 is installed in front of the chromatograph / analyzer.

Surplus oil is removed from the sampler through the safety drain to the drain.

The sampler has an emergency drain to prevent the liquid part of the sample from entering the chromatograph.

The work of the sampling device for extracting equilibrium steam of the cyclic type is carried out as follows. The oil product sample through the heated pipeline 1 through the sampling compressor 2 enters the pressure regulator 3 in sulfinert design, where it is reduced and at a fixed flow rate through the rotameter 4 enters the heated sampling device 5 through the nozzle 7 in the form of a fine suspension.

Upon reaching a predetermined level using the level gauge 17, and the vapor / liquid phase ratio in the range of 10-90 wt. % / 90-10 wt. % shut-off valve 11 closes, the sample supply is stopped. The sampling device is heated in the temperature range from 20 to 150 degrees Celsius, at which organochlorine, sulfur-containing compounds, formaldehyde pass from the liquid phase to the vapor phase, which accumulates in the upper part of the sampler. In addition, the sampling device provides for bubbling with a heated inert gas for efficient extraction of the measured components into the vapor phase. After reaching phase equilibrium and excess pressure in the range from 0.01 to 3 kgf / cm2, which is measured by pressure sensor 19, valve 15 opens and equilibrium steam is transferred from the sampling device to the dosing loop of the dosing valve 8 of the analyzer (industrial, laboratory chromatograph) along a heated supply lines 9. The dosing loop has a volume of 100 µl. up to 5 ml., where quantitative and qualitative analysis takes place. To prevent the ingress of residual liquid suspension into the sample supply line in front of the analyzer (laboratory and / or industrial chromatograph), a coalescent filter 10 is installed. The liquid part of oil products is drained out through a drain located in the lower part of the sampling device. The sampler has an emergency drain that prevents the liquid part of the sample from entering the analyzer (laboratory and / or industrial chromatograph) and a safety valve that is triggered at an overpressure of more than 3 kgf / cm2. After removing the analyzed oil products, the cycle is repeated. The device is heated using steam or electric heating until the temperature is set in the range of 20-150 degrees Celsius, the volume of filling with the mixture is from 0.05 to 2 liters, the transfer of equilibrium steam is carried out into the dosing loop 8 of the analyzer, laboratory or industrial chromatographs are due to the pressure drop. Heating control is carried out using a temperature sensor 20. The effectiveness of the method is ensured by maintaining the ratio between the vapor and liquid phases in the sampler in the following range of vapor / liquid ratios within - 10-90 wt. % / 90-10 wt. %. Sampler volume from 0.11 to 4 liters. The sample in the sampler is preliminarily thermostated at a temperature of 20 to 150 C for 2-60 minutes. With the help of instrumentation and automation fittings (hereinafter referred to as instrumentation and A), inert gas is bubbled up to a given pressure value. After stabilizing the pressure, the vapor phase is transferred to the dosing loop of the dosing valve 8 of the chromatographic system.

The analysis procedure after the process of preparation and sampling and its submission to the devices is as follows:

Sample from the sampler in a volume of 10 μl to 5 ml. after dosing, it enters the guard column, where interfering components are cut off, and the target components enter the main analytical column, where they are separated at a temperature of 50 to 350 ° C. Then the components are registered by the detector. Separation of sulfur-containing components occurs on a capillary column at temperatures ranging from 50 to 350 ° C. Formaldehyde is determined on a capillary column at temperatures ranging from 50 to 350 ° C. The calibration of the analyzer (industrial and / or laboratory) chromatograph is carried out according to the method of absolute calibration. A method for the quantitative and qualitative determination of the content of individual organochlorine compounds, sulfur-containing compounds, formaldehyde in oil, naphtha, kerosene, gas oil, diesel fuel, naphtha fraction, fuel oil, gasoline, complex hydrocarbon mixtures, chemical reagents using an analyzer (laboratory and industrial) chromatograph by the method of analysis equilibrium steam in cyclic or continuous modes consists in passing a sample flow at a rate in the range from 1 to 1000 ml / min through an automated sample preparation system of an in-line analyzer (laboratory and industrial) chromatograph, in which the equilibrium steam is heated and stabilized at a temperature from 20 to 150 ° C. The vapor phase transfer procedure is carried out by means of a pressure drop, using special pneumatic devices for gas chromatographic vapor phase analysis. For this, the sample in the sampler is preliminarily thermostated at a temperature of 20 to 150 ° C for 2-60 minutes. With the help of instrumentation and A fittings, an inert gas is bubbled up to a given pressure value. After stabilization of the pressure, the vapor phase is transferred to the dosing loop of the dosing valve of the chromatographic system. After dosing, a sample in a volume of 10 μl to 5 ml enters the guard column, where interfering components are cut off, and the target components enter the main analytical column, where they are separated at a temperature of 50 to 350 ° C. Then the components are registered by the detector. Separation of sulfur-containing components occurs on a capillary column at temperatures ranging from 50 to 350 ° C. Formaldehyde is determined on a capillary column at temperatures ranging from 50 to 350 ° C. The analog signal from the detector is converted to digital. The digital signal is recorded unchanged in the form of a chromatogram. The chromatogram is displayed as a combination of peaks corresponding to the found target components and their concentrations. Further, the automated software, using correction factors, recalculates the content of the found components from the vapor phase to the liquid phase. Measurement data is stored in the chromatograph, generated in a report and transmitted via Ethernet, RS 485, 4-20 mA interfaces to the data collection and processing system. The calibration of the analyzer (laboratory and industrial) of the chromatograph is carried out in automatic mode according to the method of absolute calibration using vapor-phase sources of gas mixtures (PIGS) or certified gas mixtures (ATC).

According to the proposed method, components of individual organochlorine compounds, sulfur-containing compounds, formaldehyde in oil, naphtha, kerosene, gas oil, diesel fuel, naphtha fraction, fuel oil, gasoline, complex hydrocarbon mixtures were identified.

The detection limit for organochlorine compounds in oil was 10 ppb.

The list of chlorine-containing components that can be determined using the invention:

Thus, this method for the determination of organochlorine and sulfur-containing compounds in oil has serious advantages over standard methods. The study does not require preliminary distillation of oil, which simplifies the analysis and excludes the possibility of the loss of light organochlorine and sulfur-containing compounds. The identification of individual organochlorine and sulfur-containing compounds makes it possible to find out whether they are natural or technogenic, which is important for introducing a method to reduce the negative impact of these compounds on oil refining processes. Standard methods for the determination of organochlorine and sulfur-containing compounds are rather laborious and time-consuming, so they are inferior to the chromatographic method. In addition, this method has the best precision indicators.

Among other advantages of the claimed group of the invention, the following should be noted.

The detection limit for organochlorine was noted at the level of 1-10 ppm.

The possibility of using flow chromatographs and avoiding manual labor has been realized.

For this method, the possibility of introducing digital technologies is obvious - remote diagnostics of all devices and their parts, checking the correct operation of the device and the dosing system, checking the reliability of measurements under specified conditions in the "on-line" mode, remote verification of the chromatograph together with the dosing device, certification of products in online mode

An increase in the reliability of measurements has been achieved by transferring the sample directly to the vapor-phase sampler - there is no distortion of the sample composition and no leakage from the sample of volatile components as a result of repeated sampling and dosing of samples (first into the sampler in accordance with GOST 2517-2012 with the presence of a vapor phase, then with a syringe manually through a packed with glass fiber liner into the evaporator of the chromatograph, in this case there is a repeated change in the composition of the sample with uncontrolled and insufficiently fully investigated physicochemical processes).

The possibility of using the following equipment

LGH - laboratory gas chromatograph;

PGC - flow chromatograph;

KhMS - chromatomass spectrometer;

PChMS - flow chromatography-mass spectrometer;

ECD - electron capture detector;

FPD - flame photometric detector;

PPFD - pulsed flame photometric detector;

MSD - mass selective detector;

TCD - thermal conductivity detector;

FID - Flame Ionization Detector;

Devices used in the method - analyzer, LGH, PGH, KhMS, PCMS with electron capture detectors (ECD), flame photometric detector (FPD), pulsed flame photometric detector (FPD), halogen selective detector (HSD), mass spectrometric detector (MSD), thermal conductivity detector (TCD) and flame ionization detector (FID).

Claims (7)

1. A method for detecting the content of individual organochlorine, sulfur-containing components of a hydrocarbon mixture by chromatographic analysis of steam, including taking a sample of equilibrium steam and supplying steam through a pipeline or a nebulizer to a continuous or cyclic sampling device with a compressor in the form of a finely dispersed gas-liquid fraction at a rate of 1-1000 ml / min, heating the sampling device to 20-150 ° C, ensuring the transition of the analyzed components to the vapor phase, accumulating in the upper part of the sampler, while for more efficient extraction of the determined components into the vapor phase, bubbling is carried out with a heated inert gas, and after reaching phase equilibrium, provide the transfer of equilibrium steam from the sampler by opening the valve from the sampler into the dosing loop of the dosing valve of the analyzer / chromatograph through the feed line with or without heating, and the loop is made with a volume of 10 μL to 5 ml, za It is dispensed into the chromatographic guard column to separate interfering impurity components, and the target components are sent to the next main analytical chromatographic column, where they are separated at a temperature of 50-350 ° C, and registered with a detector, and the liquid part of oil products is discharged through the drain located in the lower part of the sampling device, while ensuring the filling level of the sampling device is carried out using a level gauge or according to the pressure value. 2. A method according to claim 1, characterized in that the sample is dispensed by a pneumatic method of dispensing according to a pressure drop, a known sample volume, given by the pressure difference in the sampler and in front of the column. 3. A method according to claim 1 or 2, characterized in that a gas chromatograph, or a flow chromatograph, or a chromatomass spectrometer, or an analyzer is used as the analyzer / chromatograph. 4. The method according to claim 1 or 2, characterized in that the analyzed mixture is oil, naphtha, kerosene, gas oil, diesel fuel, naphtha fraction, fuel oil, gasoline, complex hydrocarbon mixtures, chemical reagents. 5. A sampling device for extracting equilibrium steam of continuous type for a method for detecting the content of individual components of a mixture, including a sampler with a sampling compressor, a pressure regulator in sulfinert design and a rotameter, a sulfinert sampling chamber is located in the center of the sampler for supplying a sample in the form of a fine gas-liquid fraction through a pipeline or a nebulizer , while the device is equipped with a heated / unheated steam supply line - a heated pipeline with a chromatograph / analyzer dosing valve made with a dosing loop with a volume of 10 μL to 5 ml, and filters to prevent residual liquid aerosol and mechanical impurities from entering the sample supply line, installed in front of the chromatograph / analyzer, as well as bubbling with heated inert gas. 6. A sampling device for extracting equilibrium vapor of a cyclic type for a method for detecting the content of individual components of a mixture, including a sampling device with a volume of 0.11-4 liters, a sampling compressor with a pressure regulator in sulfinert design, a nebulizer and a rotameter, and to achieve a predetermined level of vapor / liquid, a device equipped with a level gauge and a shut-off valve, the analyzer is made with a dosing valve having a dosing loop with a volume of 10 μl to 5 ml, the device has a heated pipeline - a supply line, is made with the provision of bubbling with heated inert gas, and is equipped with a pressure sensor with a valve for transferring equilibrium steam from the sampling device into the dosing loop of the analyzer dosing valve through a heated feed line, filters are installed in front of the analyzer, and a drain for the liquid phase and an emergency drain are made in the lower part of the sampling device to prevent the liquid part of the sample from entering the analyzer, and a fuse ny valve, which is triggered at an excess pressure of more than 3 kg / cm ² . 7. The device according to claim 6, characterized in that it is equipped with a level gauge to ensure the filling level of the sampler.

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