SU1408360A1 - Method and apparatus for chromatography analysis of gas mixtures in hydrogen - Google Patents

Abstract

This invention relates to gas chromatography. The goal is to increase the sensitivity and accuracy of the analysis by increasing the degree of concentration of the analyzed impurities, which is carried out using two series-connected enrichment columns filled with different intermetallic powder. composition. An additional enrichment column is connected to the device, connected to the first enrichment column by a channel in which a controlled shut-off valve is installed. 2 sec. and 3 z. p. f-ly, 2 ip. i (L

Description

00

with

Od

OTHOCHTICH invention to gas

chromatography and can be used to analyze the impurities of gases in a crop with the method of column chromatography;

I The purpose of the invention is to increase the sensitivity and accuracy of the chromatographic analysis.

Fig. 1 shows the device at 1: the concentration of impurities in the dynamic mode, general view; figure 2 Oh, with the concentration of impurities | static mode.

The device contains the first (basic) enrichment column 1, which is a stainless steel tube filled with alumina powder forming a hydride with hydrogen, for example, intermetallic compound I eTi. Column I has an input channel; i for supplying the analyzed hydrogen to it, in which a pressure gauge 3 (pressure gauge) 3 and a control shut-off valve 4 are installed, and one channel 5 for outputting concentrated impurities from column 1, into which - the vopoM is installed a controlled shut-off valve 6. The enrichment column 1 is placed in the thermostat 7, equipped with a controlled heating system up to 150–200 s) and cooling (up to room temperature) column 1. The outlet 5 of the enrichment column 1: United through controlled locking 1shapan 6 with the second entrance (additional An additional) enrichment column 8 is blistered or in the form of a tube made of: stainless steel, filled with intermetallic powder, which is supplied with a furnace 9 installed with the possibility of moving along the length of column 8 (fig. O, or in the form of a container partially filled with intermetallide powder, for example, LaNi and placed in a thermostat 10 equipped with a system for controlled heating and cooling of the column B (Fig. 2). The output, channel 11 of the supplementary enrichment column 8 valve 12 is connected to the device 13 for ne transfer of concentrated impurities to a chromagraphic column 14, filled with a particle of AI sorbent (molecular sieves, activ. {coal, etc.).

A device 13 for converting concentrated impurities to a chromatography column 14 may be

5 0 5 0.

five

0

five

made in the form of a spool-type dosing valve and has a channel 15 for feeding the carrier gas to the chromatographic column 14 and a channel 16 for dumping a part of the concentrated impurities into the atmosphere. A detector 17 is installed at the output of the chromatographic column 14, for example, a thermal conductivity detector. To facilitate (accelerate) the regeneration of the enrichment columns I and 8, before starting the analysis cycle, a vacuum pump 18 is connected to the device, connected to the output of the additional enrichment column 8 via a controlled shut-off valve 19. To facilitate the periodic activation of the intermetallic powder in the enrichment columns 1 and 8 The device is supplied with a source of pure hydrogen 20, which is connected to the input of the main concentration column G via a controlled shut-off valve 21. To control the regeneration modes of the concentration Lonoke 1 and 8 and activate modes therein intermetallic compound powder at the inlet of the vacuum pump 18 and the outlet 20 of pure hydrogen source installed meters 22 and 23 respectively, pressure, and

The device provides for the use of other valves to stabilize and control pressures and flow rates of gas flows (not shown). In addition, column 1 is equipped with a channel 24 for the discharge of pure hydrogen, in which the valve 25 is installed.

The method is implemented as follows.

Valves 4, 6, 12, 19 and 21 are closed before analysis. The volume of intermetallic powder in column 8 is 10 to 30 times less than the volume of intermetallic powder in column 1. Then valve 4 is opened and the flow of the analyzed hydrogen under pressure exceeding the equilibrium value (5 to 10 atm) is fed to enrichment column 1, the temperature of which is maintained equal to 25 - 30 ° C. As the flow of hydrogen moves along column 1, impurities contained in hydrogen and not absorbed on the intermetallic powder begin to concentrate on the front of the hydrogen band and at the end of the saturation process of column 1 with hydrogen GOVERNMENTAL tsentrirovan- impurities is disposed at the exit

from column 1. Then, the supply of the analyzed hydrogen to column 1 is stopped, shut off valve 4, and valve 6 is opened, venting the strip of concentrated impurities to column 8. At the same time, along with impurities, some part of hydrogen is removed from column 8 (1-5 vol.%), first-. entered in column I.

The valve 6 is closed and the valve 12 is opened, the output of the enrichment column 8 is connected to the device 13 for transferring the concentrated impurities from the column 8 to the chromatographic column 14. The opening time of the valve 12 should be short (no more than 10-20 s) and sufficient to fill the dosing volume of the device 13 and the transfer of the dosage amount of impurities into the carrier gas stream supplied to the chromatographic column 14. The operation of dosing concentrated impurities into the chromatographic column 14 can be repeated at a time (up to 6-10 times), while the pressure drop in the enrichment column 8, accompanying each operation of sampling and introducing a sample of concentrated impurities into the chromatographic column, is compensated either by moving the furnace 9 onto column 8, which leads to compression of the concentrated impurity band on the layer metal alloy particles, in column 8 and the pressure exertion in it (FIG. 1), or by raising the temperature of the entire volume of the thermostatted column 8 (FIG. 2) ,.

After the analysis process is completed, the beneficiation columns 1 and 8 are subjected to thermal regeneration. Column 1 is regenerated with valves 4 and 6 closed and valve 25 open by raising the column temperature to 150-170 ° C. The desorbed pure hydrogen is discharged from column 8 through valve 12 and the device discharge channel 16 and to the atmosphere. The regeneration of the column 8 can be more complete and is completed in a shorter time if, along with the thermal factor, the vacuuming of the column volume is used with a vacuum pump 18. For this purpose, open the valve 19, close the valve 12 and turn on the vacuum pump 1-8. After regeneration, columns 1 and 8 close the valves on

the inlets and outlets of columns I and 8 and the columns are cooled to room temperature, thus preparing them for the next analysis.

During the long process of use, the activity of the powders of the intermetallic compounds filling columns 1 and 8 is reduced. For this reason, it is required to periodically activate the intermetallic powder. Activation is carried out by repeating cycles of adsorption and desorption of pure hydrogen with Untermetallide powder in columns 1 and 8, and this operation should follow the operation of regeneration of columns 1 and 8, Adsorption of pure hydrogen in columns 1 and 8 is carried out with valves 4, 12 closed, 19 and 25 and open valves 21 and 6 by saturating the intermetallic powder in columns 1 and 8 from the source. 20 pure hydrogen. The desorption cycle repeats the decommissioned decomposition operation of columns 1 and 8. With proper operation, powders of metal alloys in columns 1 and 8, which are not significantly different in their activity, can be used to conduct more than ten thousand hours of analysis. . Example 1. Analysis of hydrogen with a known impurity content of 0.02 vol.% N, j and 0.02 vol.% Ar.

The main enrichment column 1 uses a stainless steel tube with an inner diameter of 8 mm and a length of 600 mm, filled with FeTt intermetallic powder with a fraction of 10-100 microns. A cylindrical tank with a diameter of 30 mm and a height of 60 mm is used as an additional concentrator column, partially filled with LaNi intermetallic powder with a fraction of 10-100 microns. A chromatographic column with a diameter of 4 mm and a length of 2000 mm, filled with molecular sieves NaX and t, is used as a chromatographic column to separate concentrated impurities. Thermoconstituted at 100 ° C. The analysis is carried out using a device whose circuit is shown in FIG. 2. The detector is a thermal conductivity detector. The enrichment process on the main column is carried out at a column temperature of 20 ° C and a pressure of 15 kg / cm by feeding the analyzed mixture at a rate of 1 l / min at the entrance

the main column with the valves closed: Ha: f 6 and 25. At the same time, about 10 liters of hydrogen are absorbed within 10 minutes. Then close the slapan 4 and, opening the class "1 Pans 21 and 6, is fed to the column. 0, l of pure hydrogen — ts of the source of 20 pure hydrogen; release an equivalent amount of hydrogen containing concentrated yriemesi,

zykhod column 1 through valve 6 and column 8, shut off valves 21 and

t open valve 12, additionally ejecting part

8 cen- ters concentrated in a column into the dosing volume of a device 13 for transferring samples of concentrated impurities to a chromatographic column. Chromatographic results5

a column of impurities into the dosing volume of a device for transferring samples of concentrated impurities to a chromatographic column. The results of the chromatographic analysis show that the concentration of impurities N and Ar in the sample transferred to the chromatographic column is 7 vol% N. and Ar, which corresponds to a total enrichment level of impurities in the system 7000 times.

The proposed method of chromatographic analysis and a device for its implementation using a two-stage concentration provide the analysis of trace gases in hydrogen on

trace levels of gases at 10 vol.%.

what

ce de PE

Thus, the general degree of enrichment

this system is 1700 times. 25

Claims (5)

1. Method of chromatographic analysis of impurity gases in hydrogen with preliminary concentration of the analyzed impurities in two series-connected concentrating columns filled with powder — an alloy of a metal forming a hydride with hydrogen, followed by separation of concentrated impurities w w m n f P PRI mme R 2. Analysis of hydrogen with a known impurity content of 001 vol% N2.H 0.001 vol% Ag. The main chromatographic column is a rusting steel tube with an internal diameter of 8 mm and a length of 600 mm filled with intermetallic powder. Timn five share 10 - 100 microns. A cylindrical capacitance is used as an additional enrichment column. A meter of 30 mm and a height of 60 mm, hourly filled with powder of intermetlide LaN i fraction 10 - 100 microns. The conditions of the chromatographic section of the analyzed impurities and detection are the same as in Example 1. The enrichment process on the main column is conducted at 20 ° C and the pressure of ana-J1JH3HpyeMoro hydrogen supplied to the column inlet is 25 kg / cm for 1J5 min. Then close the valve in the feed tank of the analyzed hydrogen rt open the valve at the outlet of the axes-enrichment column, strati- through the head part of the hydrogen-4s containing impurities, in the | | additional enrichment column for 60 s. Then close ijoianaH at the outlet of the main concentration column and open the ijia valve at the output of the additional fortifier Yoy column, release the additional part-) (| block) concentrated in this five 0 1. Method of chromatographic analysis of impurity gases in hydrogen with preliminary concentration of the analyzed impurities in two series-connected concentrating columns filled with powder — an alloy of a metal forming a hydride with hydrogen, followed by separation of concentrated impurities on the chromatographic column and by de-detecting separated components, characterized in that, in order to improve the sensitivity and accuracy of the chromatographic analysis, after the concentrated impurities are transferred from the first concentration column to the second, the hydrogen supply to the first column is stopped and 0 the internal volume of the second enrichment column is isolated from the internal volume of the first column, while in the first enrichment column a metal alloy is used, the equilibrium pressure of hydrogen above the alloy at room temperature exceeds the equilibrium hydrogen pressure over the alloy in the second column at the same temperature. 0 2. The method according to claim 1, in order to improve the reproducibility of the results of the chromatographic analysis, to separate the gas phase on the chromatographic column, which is in thermodynamic equilibrium over the metal alloy volume of the second enrichment column. 3, A device for chromatographic analysis of gas impurities in hydrogen, containing at least two successively connected concentrating columns, filled with metal alloy powder, forming a hydride with hydrogen, pipetting the analyzed hydrogen into the first concentrating column. The rum is fitted with a controlled shut-off valve, a separation chromatographic column, the inlet of which is connected to the pipeline for supplying carrier gas, and the outlet to the detector, and a device for transferring OF DATA impurities from the second enrichment column to a separation chromatography column, about l u t-sistent with the fact that, in order to increase the sensitivity and precision of analysis, second enrichment and cash Hz fj the column is partially filled with metal alloy and the internal volume of the column free from alloy is connected through controlled shut-off valves to the output of the first concentration column and with a device for converting concentrated impurities into a separation chromatographic column, 4. The device according to claim 3, that is, with the introduction of a vacuum pump connected to the supplementary enrichment column through a controlled shut-off valve. 5. The device according to claim 3, characterized in that it is provided with a source of pure hydrogen connected to the inlet of the first enrichment column via a controlled shut-off valve. 18 22. The carrier gas 12 at 15 P 17 Jtr // / J / fS ag one. jHfUl.H 20 Ib 22 Gas-Hocufne / fb Y- / 5 13 / f6 fus.2