DE1673157A1 - Procedure for chromatographic analysis - Google Patents

Description

The invention relates to a method for analyzing mixtures of liquid or vaporous constituents, in particular such mixtures in an improved vapor phase chromatography technique, in which a solid sorbent is used as the component separating agent, which is able to retain one or more constituents of the mixture and a or to remove several other components. In particular, the invention is directed to a method for the rapid determination of one or two broad classes of constituents that are present in a mixture sample: 1) those constituents that are selectively sorbed by the sorbent and 2) those constituents that are relatively less sorbed or be repulsed · Those in the first class are determined continuously.

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The theory and application of the DaMipf phasonchrumatogrnphie are known. In the art, extensive work has been directed towards the development of a high-resolution device which is able to separate and quantitatively measure very closely related compounds in a complicated multicomponent system. Vif-le ingenious column constructions have been developed which are able to handle sample volumes in the range of liquor liters (1 / 1,000,000,000 l or even aanoliters (1 / 1,000,000,000 l). Other constructions include Cumbersome flow diagrams, multiple columns, noue column fillers, ultra-sensitive detectors, highly developed electronic circuits, etc., all of which have the goal of achieving an even higher resolution and sensitivity A facility of this type has generally proven unsatisfactory when transferred to a technical facility, e.g. a petroleum refinery, and used as a process flow analyzer because of its reliability in a detrimental Environment is lacking and it requires careful maintenance and calibration, even the very f A well-designed chromatograph for process streams that were previously available for use in field installations does not provide a complete statement and actually has at least four major disadvantages: Firstly, conventional chromatographs have an excessive performance, i.e. they provide a more detailed analysis of a multi-fuel stream than for one An operations engineer is required who is usually only interested in a key component or a group of components . Second, they require a relatively long time to elute a given sample so that the interval between analyzes is often excessively long and cannot be shortened even if the uninteresting peaks are mechanically or electronically suppressed. Third, the output is a conventional one

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Chromatograph, which consists of a series of unidirectional tips, discontinuous and therefore unsuitable for dip control of continuous processes, unless with the help of special auxiliary equipment which reduces the costs of the Increase investment and decrease profitability. Fourth, it is necessary in understanding the percentages of A in a mixture of the constituents A, B and C wants to calculate, by integration, the area under each of the peaks, which correspond to the components A, B and C, add the integrations and the area for A given by the sum obtained to divide. This is a tedious and time consuming job when done by hand. But it will be electronic done, it requires cumbersome and expensive computing, and in any case the frequency of determinations remains limited due to the sample elution time.

The invention largely eliminates the above disadvantages of the well-known chromatographic analyzers a specially pretreated solid sorbent as filling material for chromatographic column. Various solid sorbents special composition and structure are known which have the ability to selectively sorb one or more components of a mixture and one or more others Allow components to pass through or repel, providing a means of secreting the individual components accordingly its structure is created. The physical or chemical mechanisms by which the respective sorbents are used for certain Multicomponent mixtures are able to work can be different. For example, the typical sorbents that are due to their adsorptive properties work, silica gel, activated carbon, Aluminum silicates, such as the various clays and activated silica gels, including e.g. attapulgus clay, montmorillonite, appropriately dehydrated mixtures of alumina and silica, which by heating to a temperature slightly above the Melting point of the mass are activated, and activated alumina. Sorbents that work by means of molecular inclusion are the

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dehydrated metal alurainium silicate hydrates, wherein the metal component consists of alkali or alkaline earth. They are commonly referred to as molecular sieves. These and other types of sorbents and methods of using them are known in the art. All of the above sorbents can according to the invention be used.

According to a typical embodiment of the invention, a continuous flow of carrier gas, such as helium, initially through a pull-in cell for heat conduction, then subsequently by a Separating column and a measuring cell for thermal conductivity. An injection device is provided in order to directly take samples of a certain volume of the flowable mixture to be analyzed injected into the carrier gas stream between the reference cell and the separation column. The reference cell and the measuring cell are connected to a suitable bridge circuit, driving a potentiometric recorder. These Elements are known. It has been discovered, however, that if the column is filled with a solid sorbent, this leads to the selective Sorption of one or more, but by no means all of the constituents present in the sample is capable, and verm further the sorbent with at least one of the selectively aorbed Components is presaturated, then a truly continuous determination of the selectively sorbed material can be obtained can. The presaturation of the sorbent can be achieved by treating it with the selectively sorbed component or components either in pure form or in a mixture with relatively little sorbed or nonsorbed components that are not in need of sorption take place before filling into the separating column. The presaturation can also be effected in situ after the Sorbent was poured into the column by repeating injects a sample until substantially acidification is achieved. First of all, it should be noted that the column with fresh or only partially saturated sorbent filled wildly so that the carrier gas flow receives the appropriate speed, that the column temperature is kept at the appropriate level

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and that the parameters of the bridge circuit are regulated so that this results in an electrical zero value in the recording device. It is assumed that the liquid or gaseous mixture to be analyzed is a binary mixture made up of a selectively sorbed component and a relatively low-sorbed component. A first sample is injected and a short time later a peak is recorded corresponding to the passage of the less sorbed component through the measuring cell. The recorder spring returns to zero and remains there while the selectively sorbed component originally present in the sample is taken up by the sorbent and is not stripped or desorbed by the carrier gas. The same response is obtained for each subsequent sample injected until the sorbent becomes saturated with respect to the selectively sorbed component. When the acidification occurs, the selectively sorbed component begins to flow out of the separating column at a steady rate, even though another sample has not been injected, and the recording spring will suddenly jump up the scale a substantial distance above the electrical zero value corresponding to the passage of the selectively sorbed component through the measuring cell. This record is not a "peak" but a constant "baseline" above electrical zero that continues for a substantial time after the last previous sample injection, and the magnitude of such elevation has been remarkably proportional to the amount of weight in the sample existing selectively sorbed "component found. Fenn now samples of the liquid or gaseous mixture are injected periodically below and the concentration of the selectively adsorbed component is different in each, the analyzer reading a peak soon after each sample injection (due to the less adsorbed component) have the form , which is placed on a continuous, time-dependent, higher-lying "baseline", the latter precisely varying

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Content of the selectively sorbed component in the series of Rehearsals follows. The deviation above the electrical zero value after the peak for the less sorbed component provides a continuous measure of the content of the selectively sorbed component of the binary system used in samples, The analyzer converts the data entered in individual samples into a continuous recording.

Next, consider the case in which the liquid or gaseous mixture to be analyzed is a multicomponent mixture is made up of two or more selectively sorbed components and one component that is relatively less sorbed. After a series of sample injections, the sorbent is saturated with selectively sorbed material, which is then treated with a uniform speed and no difference or chromatographic Separation eluted among the various selectively sorbed components. The record of the analyzer has the same form as when the liquid or gaseous mixture is a binary system, with the exception that now the higher baseline after the less sorbed component has been passed through the separation column * proportional to the total content is the selectively sorbed component in the mixture. In fact, the analyzer deals with the multi-component noise like a pseudo binary system.

Furthermore, the case is examined in which the liquid or gaseous Mixture to be analyzed, at least two selectively sorbed components and at least two relatively low sorbed components. After the sorbent with selectively sorbed material is saturated, causes a repeated and continued injection of samples a continuous "higher lying baseline, which is determined by the continuous, indiscriminate elation of the various selective sorbed components are produced »

When the temperature of the separating column is sufficiently low, it takes place nevertheless a chromatographic separation of the less sorbed components so that the recording of the

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Analyzer shows a series of peaks after each sample injection, corresponding to the specific constituents of the less sorbed class, these peaks emanating from the raised baseline. While this type of analysis can be widely used and is within the spirit of the invention, it is also desirable and possible to make the analyzer record as if the liquid or gaseous mixture were binary. This is accomplished by raising the column temperature to the point where all of the less sorbed components are eluted from the column almost immediately and without discrimination, while the selectively sorbed components continue to elute uniformly, even without discrimination, thereby creating a "concentration effect". The recording of the analyzer after each sample injection now takes the form of a single narrow spike that arises over the raised baseline, the latter being proportional to the total content of the selectively sorbed component of the sample. When working in this way, for example to perform a pseudo binary analysis, the analyzer only distinguishes between two broad classes of constituents: those that are selectively sorbed and those that are relatively little sorbed. However, such information is often invaluable to the process engineer who is seeking to optimize the performance of a particular iron component or port refiner, such as a distillation column, and who is not interested in analyzing the individual compounds in a process stream. The pseudo binary analysis has the additional advantage that the elution time per sample is generally the shortest, so that samples can be introduced more frequently. The necessary column temperature to achieve the concentration effect depends on various variables, such as the jorbonsart, the specific compounds in the mixture to be analyzed, the flow rate of the carrier gas, etc., but can in each case be determined by routine experiments with a special system.

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It will be appreciated that the method of this invention differs in at least four important respects from known chromatographic Analyzers differentiate:

1) At least one of the components of the analysis mixture is continuously eluted from the column, regardless of the interrupted one Sample injection, and at least one other component is eluted discontinuously, on the contrary? to conventional Chromatograph in which each specific component eluted discontinuously as a binary mixture with the carrier gas.

2 ) If the analysis mixture contains two or more selectively sorbed constituents, these are eluted from the column continuously and without distinction. This technique results in a negligible separation between the particular selectively sorbed constituents, in contrast to known scientific endeavors which attempted to obtain a strong separation between all the particular components of the analysis mixture.

3) If the analytical mixture is two or more less sorbed Containing components are in a preferred embodiment of the invention these components simultaneously or substantially simultaneously within a very short time after sample injection eluted, and their transit time through the measuring cell is short compared to the interval between sample injections.

k) The elution time per sample is significantly shorter than that of conventional chromatographs. Advantages of the present method are as follows; A continuous recording signal arises from a discontinuous feed, with varying component concentration being followed more closely and with the method being easier to use in conjunction with analogue standard control elements to form a closed system. A single component or a group of components creates a uniform signal

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proportional to their weight concentration. This signal is continuously for selectively sorbed components and can be used in a single tip for less sorbed components, thereby reducing the calculation of the for the automatic Reading of the component with a high work of separation required current is switched off. The relatively short elution period allows the more frequent introduction of the Samples and therefore increased accuracy and decreased 'lag time, the use of a solid sorbent as a filling material for the chromatographic column eliminates problems of stability and substrate evaporation. that of conventional filling materials emerge, which consist of an inert, solid carrier, which with a high-boiling organic liquid Substrate is oversize.

Accordingly, the invention provides a method for analyzing a mixture of liquid or gaseous components, at least one of which is selectively sorbed by contact with a solid sorbent and at least one other component is less sorbed by the sorbent. This procedure consists in putting a mass of the sorbent through it Pretreated contact with the selectively sorbed component, until the sorbent is substantially saturated with the selectively sorbed component, collect a sample of the mixture with a carrier gas flow through a separation zone, which is the front acted Sarbens contains, leads and the outflow from this zone to a measuring cell, which due to the outflow emits an electrical signal indicating the content of the selectively sorbed component in the mixture.

When analyzing a mixture of liquids or gases Components at least one of which is selectively sorbed by contact with a solid sorbent, and at least one of which two other components are absorbed by the sorbent in a proportionally lower proportion, the temperature of the zone becomes sufficiently high 90 then all components are kept in the vapor phase, and the less absorbed compounds are

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eluted from the separation zone at substantially the same time. Preferably a stream of the carrier gas is continuously passed through passed the separation zone and samples of the mixture are added at periodic intervals to the carrier gas stream at one point introduced in the upstream direction from the separation zone.

A preferred solid sorbent is a material characterized as pin dehydrated metal aluminum silicate hydrate, wherein the metal component is an alkali or alkaline earth metal. These materials are also known as molecular sieves'. These sorbents are particles with pore diameters in the range of 3 to 7% and are capable of selectively sorbing a variety of compounds depending on the particular pore diameter range and size distribution. The molecular sieves can be produced by precipitating aluminum oxide, silicon dioxide and a metal oxide, such as an oxide or hydroxide of an alkali metal such as sodium, lithium or potassium, or of an alkaline earth metal such as calcium, magnesium, barium or strontium, together or combining them in some other way, in order to form a uniformly and intimately dispersed mixture of silicon dioxide, aluminum oxide and the metal oxide or hydroside by removing excess water from the mixed oxides and then heating the dispersed mixture obtained to a temperature at which the water of hydration evaporates from the Particle is expelled. The resultant dehydrate mixed oxides v; erderi preferably calcined at a temperature of about 20h to h27 C, in order to improve the hardness and strength of the particles. Processes for the production of molecular sieves are described in detail in the literature.

Using a specific embodiment of the invention of molecular sieves as packing material for chromatography Column provides a method for analyzing a hydrocarbon mixture which is at least one non-aliphatic Hydrocarbon and at least one abnormal

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contains branched chain or cyclic hydrocarbon. The normal aliphatic hydrocarbon is selectively sorbed through the molecular sieves and elutes continuously from the column after the molecular sieves are saturated. The abnormal hydrocarbon is passed through the sieves and eiuiert as a band soon after the top injection. The normal aliphatic hydrocarbon can be saturated or unsaturated, such as a normal paraffin or a straight chain olefin, diolefin or polyolefin, and can contain from one to about 22 carbon atoms. The abnormal hydrocarbon can be a branched chain paraffin, olefin, diolefin, or polyolefin having h to about 22 carbon atoms, a cycloparaffin or ™ cycloolefin having h to about 22 carbon atoms, or a mononuclear or tubular aromatic hydrocarbon having from about 6 to about 22 carbon atoms. If the constituents subjected to chromutographic separation are in the vapor state, hydrocarbons with less than 22 carbon atoms can generally not be analyzed by this method because they are too difficult to evaporate even if the hydrocarbon partial pressure is reduced by excess amounts of Carrier gas is significantly reduced, and instead they tend to thermally decompose and deposit coke on the column oil. If the normal aliphatic hydrocarbon is a normal paraffin, *

therefore, it contains from 1 to 22 carbon atoms, and preferably it is one containing from h to 18 carbon atoms. The non-normal hydrocarbon can contain 4 to about 22 carbon atoms and preferably has h to 18 carbon material streams at. The "concentration effect" is most easily achieved when

the mean carbon number of the analysis mixture about 6 to Does not exceed 8 carbon atoms.

The invention is particularly well suited for the analysis of kerosene fractions comprising one or more normal paraffins having 10 to 1 carbon atoms and one or more non-normal hydrocarbons having 6 to 16 carbon atoms.

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For an analytical mixture of this type, the temperature of the molecular sieve column should be at least 315 ° C. and preferably somewhat higher, e.g. in the range from 321 to 3 ° C. On the other hand, to obtain non-normal hydrocarbons. Below 315 C, on the other hand, a slight separation of the C -C fraction will begin. A typical analysis mixture can comprise a larger proportion of normal paraffins and a smaller proportion of non-normal hydrocarbons, the height or area - under the peak for the non-normal hydrocarbons, placed on the continuously raised baseline for the normal hydrocarbons, providing a measure of the total content of non-normal hydrocarbons in the sample . Another typical analysis mixture can comprise a larger proportion of non-normal hydrocarbons and a smaller proportion of normal hydrocarbons, the distance from the zero value after passing through the non-normal hydrocarbon peak providing a continuous measure of the total normal paraffin content of the sample.

Using another specific embodiment of the invention of molecular sieves as packing material for the column provides a method for the continuous analysis of Water in ο an internal mixture of water with one or more of the following less sorbed materials: methane, atane, Propane, isobutane, hexane, oxygen, hydrogen, nitrogen, air or natural gas. The vreniger will be sorbed materials passed through the sieves and eluieron from the column as a coherent band there soon after injection Sample. The water vapor becomes selective through the Molokularsiele sorbs and elutes after saturation of the See ο continuously with it, to give an elevated baseline signal, its Height after going through the top for the less sorbicrteii Jatorialion pruport j onul dom water content of the sample is.

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Corresponding further special embodiments of the invention using molecular sieves as filling materials for the column provide processes for the following continuous ones Analysis:

. Determination of hydrogen sulfide or mercaptans in a mixture of hydrogen sulfide or mercaptans with one or more of the following, less sorbed Materials: methane, athan, propane, normal butane, isobutane, normal pentane, isopentanes, normal hexane, normal heptane, Norine octane, hydrogen, carbon dioxide or natural gas. The sulfur compounds are made through the molecular sieves selectively sorbed.

2. Determination of carbon dioxide in a mixture of carbon dioxide with one or more of the following less sorbed materials: methane, ethane, ethylene, propane, butane, Pentane, nitrogen, hydrogen and carbon monoxide. That Carbon dioxide is selectively sorbed by the molecular sieves.

3. Determination of unsaturated C -C ^ normal aliphatics Hydrocarbons in a mixture of one or more such unsaturated hydrocarbons with an or several of the following less sorbed materials: methane, atane, oxygen, hydrogen, or nitrogen. The unsaturated hydrocarbon is selectively sorbed by the molecular sieves.

H. Determination of isobutane in a mixture of isobutane with one or more less sorbed C -C "-paraffins. The isobutane is selectively sorbed through the sieves »

5 «Determination of mononuclear aromatic hydrocarbons in a mixture of such mononuclear aromatic hydrocarbons with relatively less sorbed polynuclear hydrocarbons aromatic hydrocarbons. The mononuclear aromatics are selectively sorbed by the molecular sieves.

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Another specific embodiment of the invention using a solid adsorbent as a filling material for the Tolor ·.-ne, such as dehydrated silica gel, activated carbon, activated aluminum oxide, etc., provides a method for continuous determination of mercaptans or amines in a mixture of mercaptans or amines with a paraffinic one Hydrocarbon fraction. The paraffins that are in proportion less adsorbed pass through the adsorbent and elute from the column as a coherent band soon after injecting the sample. The polar mercaptans or amines are selectively adsorbed and elute after saturation of the adsorbent with them continuously and yield a increased baseline signal, the height of which after passing the peak for the paraffins is proportional to the content of the Mercaptans or amines of the sample.

Using other specific embodiments of the invention of a solid adsorbent, such as from dehydratedi Silica gel, activated carbon, activated aluminum oxide, etc. as filling material for the column are about the following:

1. Determination of olefins in a mixture of olefins and Paraffins. The olefins are selectively adsorbed.

2. Determination of aromatic hydrocarbons in a mixture of aromatic hydrocarbons and non-aromatic hydrocarbons. The aromatics will selectively adsorbed,

3. Continuous determination of water vapor in a mixture of water vapor with air, nitrogen or others Inert gases or paraffinic hydrocarbons. The water vapor is selectively adsorbed.

The invention is explained in more detail in connection with the drawing , in the:

Figure 1 is a schematic diagram of a process stream analyzer after, the invention, ...- ",

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Figure 2 is a schematic diagram of a bridge circuit for obtaining a signal recording in the Plant of Fig. 1 and

3 shows a representation of a typical signal recording according to the method of this invention.

Fig. 1 shows in a partial section a linear sample valve 10, which has outer'otator plates 11 and an inner reciprocating piston 16 in gas- and liquid-tight contact with the plates 11. The stator 11 is with holes 12, 13, 1h and 15 provided. The piston 16 is provided with three transverse bores 17 »18 and 19. The middle bore 18 has a slightly smaller diameter and represents the sample or measuring opening. The piston 16 is set in one of its two by means of a rod 20 which is connected to an upper, cylinder switch 21 and also to a lower membrane switch getrioben layers, V- e did FINISH s air to the switch 21 or via line 2h the switch 23 is fed alternately by suitable, not shown, automatically programmed valve means through line 22nd If one of the lines 22 and 2'h is under pressure, the other line is ventilated at the same time. When the oclial part 23 is pressurized, the piston 16 is moved upward into the position shown, which is the "sample opening back filling valve": the bores 12, 18 and 13 communicate in series. The holes h 1, 19 and I5 Communi- pit, in another row, and bore 17 is ineffective. ^Tr enii doi ichalter 21 is under pressure, the piston 10 is moved into the "trial injection position"; the holes 12, 1? and 13 now communicate in one row, while the holes | 4, 18 and 15 in another row kornmunizt'Tfii. and the bore 19 unu ij ksa.i; is. The Probenvontil 10 is enclosed by an electrically heated, thermostatically controlled ■ share 25 which holds the valve at a sufficiently elevated temperature to the sample after Vunsch completely udor / u partially evaporate. A circulating sample stream of the zu

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analyzing process & «4 fluid is passed through inlet line 26, filter 27 and" line 28 to valve 10. Exits "either through bore 18 or bore 1.7 and is withdrawn through line 29, flow regulator 30 and line 31, from where it. continuously returns to a point in the process at a lower pressure than the inlet. The volume and length of the pipelines of the sample loop should be kept as small as practically possible in order to keep lagging through the transport to a minimum. A carrier gas source 32 is connected to the analyzer by line 33. The carrier gas preferably consists of helium, but can also consist of neon, argon, hydrogen, nitrogen, CO or some other inert gas which, in its thermal characteristics, differs significantly from the constituents of interest in the sample atom. Carrier gas is fed from line 33 via the flow regulator 3 ^ i line 35 »thermal conductivity reference cell 36 and line 37 to valve 10. It goes either through bore 18 or bore 19 and then through line 39 to the separation column 39, which contains a suitable solid sorbent. Vapor effluent from the column 39 passes through a - Heat lei-tf ähigkeits measuring cell kO and is then blown hl by conduction. It should be noted that other types of detector devices can be used instead of the thermal conductivity cell, for example this can be a toning detector or a ß-radiation detector. The cells 36 and '(O as well as the column 39 are encapsulated in an electrically heated, thermostatically controlled detector block h2 , which keeps the temperature at a sufficiently high temperature to vaporize all components of the sample. If the sample mixture is more than one selective sorbed constituent or contains more than one less sorbed constituent, the temperature should be high enough to prevent any noticeable separation e.g. between the selectively sorbed constituents and preferably also between the less sorbed constituents

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Mounted in: a temperature controlled housing 43 that ^{: has} an internal temperature in the range of about 15 to 50 C (60 to 120 ° F). '} ^: '' ,

When the valve 10 is in the position for replenishing with sample, flow through the holes 18 and hearth through the lines 29 and. 31 ', in the process or / a' suitable basin or drainage aurücfc. Carrier gas W ^ d through, the lines 33 ^u frd 35 2tidei ⁵ reference ze lie 36, goes through the bore 19, line $ 8 , column 39, measuring cell 40 ^ |

and drain line hl. In order to bring the valve 10 into the sample injection position, the piston bore 18 is quickly moved downwards so that it comes into congruence with the stator bores 14 and 15, and the sample that has entered it is carried by the carrier gas into the column 39 and from Rinsed out there to the measuring cell 40. The piston bore 17 moves downwardly in register with the stator bores 12 and 13 to provide continuity of flow through the sample loop during the sample injection portion of the operating cycle. The frequency of the sample injection can be varied from, for example, ten times per minute to once per ten minutes, depending on the mixture to be analyzed, the type of sorbent, the column length, the column temperature, etc. The response time of the generator itself can often be made less than about 5 minutes after injection of the sample. Usually, a sample injection every one to two minutes is quite adequate for monitoring a process and application as controls, and such a period is preferred to allow sufficient time to operate an auxiliary device such as a tip tap or a servo to reset the bridge By measuring the sample injections, a continuous signal record is easily obtained with regard to the selectively sorbed component or the components,

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In "FIG. 2 is a suitable two-element bridge circuit 50 ^ The one

"Side of the bridge contains a fixed resistor 51.» which lies in series with a temperature sensitive resistance 56 within the reference cell 36. The other bridge sheet contains the series combination of potentiometer 5 ^ (rough graduation), fixed resistor 53 »potentiometer k (fine zero setting) and a temperature-sensitive resistor winding 55 inside the measuring cell ko. Both sides of the bridge 50 are connected by a voltage divider 57 (weakening one division), to which a potentiometric recorder is connected transversely. A constant current source 59 supplies regulated current for the bridge 50 and via a milliammeter 60, Obviously, many other functionally equivalent circuits can be used, such as a four-element bridge, whereby the sensitivity would be doubled.

As an example of the operation and display of the invention, an apparatus of the construction described above can be used to analyze a hydrocarbon stream consisting of about 60 pounds 5 weight - '/ l ^C in ~ ^C i (. N-paraffin and about ^ O-5 weight ¹ ^ C ^ -C ^ non-n-hydrocarbons (branched chain alkanes, aromatics and naphthenes) The separation column is about 13 one (5 inches) long and about 1.75 ^cm {1 / k inch ) wide and contains about 1.9 Grai..in molecular sieves (a dehydrated calcium aluminum silicate hydrate with a porosity of about 5 A). The volume of the sample injection hole of the linear sample valve is 3 --iikro.lit.er. . The working conditions are filtered as follows:

Sample valve temperature 160-166 ° C

Detector block temperature 33O-335 ° C

Carrier gas (helium) flow 100 cur / 'Hn. at 75Ο min TTg

Sample flow 100 cm / min.

Frequency of samples - once every 60 seconds

injection

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Eluxerungη duration:

not normal k, 5 seconds

normal paraffins. infinite with saturation,

continuously after saturation.

The display of the analyzer: * is shown in FIG. 3, where the recording output 0 is plotted as a function of the time T i .vt. The abscissa means the electrical zero value, which is determined by the parameters of the Jie ss bridge switch. HiLd may or may not coincide with table 11 enaullvert. The marked "I" mean successive sample injections. During the first part of the trial, which includes peaks 61 and 62, each of which corresponds to the group of non-normal hydrocarbons, the molecular sieve sorbent is not yet essentially saturated with normal paraffins, and the normal hydrocarbons are therefore removed from the Sorbent picked up and does not exit the column. The tracer spring returns to the electric zero baseline after S1.O has passed through each of the non-normal hydrocarbon ports 61 and 62. At point "a", however, the sorbent became finally saturated with the normal paraffins, which then begin to elute continuously, with the analyzer recording suddenly increasing: The two peaks 63 and 65 represent the said non-normal hydrocarbon content of the ™ bo üi-ef fender. sample, but they are now on one elevated riaai ^ linio 6-Ί put on. Kit other t / orts , even though äio Px oboneinspx-it tongues in fairly wide open spaces At intervals of 60 secuiiilon ox-foiger », the drawing pen does not return to da ·· 'rällvprl, but rather records an essentially continuous, stable line 6'l, which is only used by the interluet tiex-endei! -pitmen fih 'the non-normal kohlonwasocx ^ stof fe ur: tcMbx-och (> ni t. The level of the T-Luxe Gk above the electrical MuI. l »rrt iut proporti oiial dei · .: total geiv'i chi s content of the NOx ¹ -malparaffj 110 "dp" uiitoräuchtei 'tJtroiiiGs and follows surprisingly- ■

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wise slight variations in the normal hydrocarbon content in succession. Samples with high accuracy. The non-

normal hydrocarbons usually elute immediately without Differentiation - and all normal paraffins elute continuously, also without distinction.

Mixtures other than those of hydrocarbons as discussed above can be used in a similar manner

.to be analyzed. In all cases a continuous- · is obtained.

Lich recording signal corresponding to the selectively sorbed Material, if a solid sorbent is used that is

Obviously the selectively sorbed. Material essentially is saturated. If the analysis mixture is more than one selective contains sorbed constituent, the temperature of the separating column is increased sufficiently so that only a © rings or no separation of the selectively sorbed constituents occurs at all. In a preferred embodiment of the invention, where the analysis mixture contains more than one less sorbed constituent, the temperature of the separating column will also be held high enough so that no noticeable separation of the less sorbed constituents occurs, and these are therefore combined together in a single peak, the is eluted soon after sample injection. In this way

A uniform signal is produced, its magnitude is proportional to the weight concentration of an individual or a group of constituents carried by the solid sorbent is selectively sorbed ", one also obtains a uniform Tip according to the weight concentration of all less sorbed components. The elution time per sample is . · Noticeably reduced compared to those of usual cbroiiiatogr-ghischen inalysatorer is supplied. Hence a higher sample frequency, increased accuracy and a reduced delay time enables. The invention allows' also a very high level of accuracy and sensitivity • with regard to the selectively sorbed material, as larger Sample volumes and / or more frequent sample injections

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applies ways, the effective concentration of sörbierten Material in the separation zone effluent can be increased many times over resulting in concentrations of the order of magnitude provide an observable output signal from 1 to 5 ppm, without the need for ultra-loud signal amplification *

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Claims (2)

Patent claims ir) Method of analyzing a mixture of liquid or gaseous components, at least one of which through Contact with a solid sorbent is selectively 'sorbed and at least one other is relatively sorbed by the sorbent is less sorted, characterized by 'that one • a mass of sorbent through contact with the selectively s-or-bated Component pretreated until the sorbent regarding of the selectively sorbed component f is saturated, take a sample of the mixture along with one Carrier gas flow through a Trenrizone, which leads the pretreated Contains sorbent, and the discharge from this zone leads to a measuring cell that develops an electrical signal, that is the content of the selectively sorbed component expressed in the mixture. 2.) The method according to claim 1, characterized in that one through a substantially continuous carrier gas train the separation zone and Hess cell conducts and samples of the mixture to be analyzed into the carrier gas flow at periodic intervals introduces before this stream enters the separation zone, whereby the measuring cell is a substantially continuous Signal developed that the content of the 'selectively sorbed Expresses constituent in the mixture. 3.) The method according to claim 2, characterized in that the Measuring cell develops a discontinuous signal that the content of the less sorbed component in dom Gei lisch expresses. . 209812/0283 "ad ordinal _; Method according to claim 2 or 3, characterized in that that the mixture has at least one component, which by Contact with the solid sorbent is selectively sorbed, and at least two other .components caused by the sorbent are proportionally less sorbed, and the temperature of the separation zone is kept at an elevated level is where all of these ingredients are in the vapor phase kept and the less sorbed components from the are eluted substantially simultaneously. 5 ·) expiry j un according to claim k, characterized in that the The temperature of the separation zone is above about 315 ° C. t | 6.) The method according to any one of claims 1 to 5 »characterized in that the selectively sorbed component is a normal aliphatic hydrocarbon and the ifeniger sorbed component is a non-normal hydrocarbon from the group of branched and cyclic hydrocarbons. 7 ») Method according to claim 6, characterized in that the« KorinaXparaf f contains 1 to 22 carbon atoms and the non-normal carbon hydrogen contains k to 22 carbon atoms. P / Verl'uhren close to claim 6, characterized in that the j Xori'iaTparaf f in ¹ I Ids l8 carbon atoms and ^v is the Nichtnormal- kohloiii.asseT'stof ^ f k to 18 carbon atoms. - Q.) Veriahren according to claim 6, characterized in that the , KormaJparaffin 10 to 16 carbon atoms and the non-normalkohloinvadei-erstof f contains 6 to 16 carbon atoms * 10.) Method according to one of claims 1 to ■ 9 »characterized in that that the sorbon is a dehydrated metal aluminum i ii cat h yd x * at is. 209812/0253 1.) Vcri'aluori to c? INEM dor An ^e prüchfc 1 to 9> dad I π gokonn- zeicbjiut that the <'orbcris is silica gel, '"!.) Failure after one of the claims« 1 hip 9 »thereby {; ο1τηη- ZOi chile I, 'dLifä the "Orbonis AktiA'koh] ο is :. 3. ) Yoriahi fMi after cinci'i der - \ nspriicho 1 his.- 9 »dudiirch ßoko.nrizeichnet that dad Sorb ο ns activated Λ lumi ni runuAyd i at. 2 098 12/025 3 BATH ORIGINAL Empty soap