METHOD AND APPARATUS FOR ANALYZING A HYDROCARBON SAMPLE

Abstract: An apparatus and method for analyzing a hydrocarbon sample comprising paraffins, naphthenes and aromatics. The apparatus comprises means for providing a sample, a polar column, a 13X molecular sieve coated open tubular column, a nonpolar stationary phase column, a valve means, detection means and means for supplying gas.

Description: METHOD AND APPARRRUS FOR ANALYZING A HYDROCARBON SAMPLE: This invention relates generally to gas chromatography and, more particularly, to the paraffin, naphthene and aranatic analysis of reformer feedstock and product. Frequent changes in feedstock quality for catalytic reformers have created a need for an on site instrument which can quickly provide information on feed and product composition changes to assist in plant surveillance and process tuning. The failure to recognize poor plant performance or upset at an early stage can lead to a serious loss in reformer yields and/or a premature need for catalyst regeneration. In the past characterizing of reformer feeds and products has generally been done by a combination of gas chromatography and analytical chemistry methods in a central laboratory which is usually remote tran the refinery. This technique is time consuming and often leads to a sizable delay between the times the sample is taken and the results are mkde available to the refinery. Therefore, it is an abject of the present invention to provide a method of a apparatus for analyzing a hydrocarbon sample fran a reformer process to provide a rapid and detailed analysis of the paraffin, naphthene and aranatic composition of the sample. The apparatus of the invention for analyzing a hydrocarbon sample comprising paraffins, naphthenes and aromatic, is characterized by means for providing a sample; a first means for supply- ing gas connected to said sample providing means, a first valve means connected to said sample providing means; a polar column connected to said first valve means for retarding the arcmatics of said sample while the remainder passes through; a 13X molecular sieve coated open tubular column (13X MASCOT column) comprising an elongated capillary tube and a layer comprising a plurality of disunited particles of 13X material disposed on the inner surface of the tube by filling the tube with a suspension comprising a dispersive liquid and 13X materials and flowing an inert gas through the tube to dry the tube thereby leaving said layer attached to the inner surface of said tube for separating the paraffins and naphthenes in said sample by carbon number, said 13X = column having a first end ccmected to said first valve means and a seced end connected to means for deterinining the amounts of paraffins and naphthenes separated by carbon number by said 13X MSCOT column; means for varying the temperature of said 13X MSCOT column; a mixed binary phrase column for separating said sample by components from C1 through at least C8, said mixed binary phase column having a first end connected to said first valve means and a second end connected to m-onc for determining the amounts of said sample separated by components from Cl through at least % by said mixed binary phase column; means for maintaining said mixed binary phase column at a predetermined temperature; a nonpolar stationary phase column for separating the aromatics in said sample, said nonpolar stationary phase column having a first end connected to said first valve means and a second end connected to means for determining the amounts of said aromatics separated by said nonpolar stationary phase column; means for varying the temperature of said nonpolar stationary phase column; a second means for supplying gas connected to said first valve means; a third means for supplying gas connected to said first valve means; said first valve means having at least a first and second position, such that in said first position, said polar column is connected to said injecting means, said 13X MSCOT column is connected to said polar column such that a portion of the effluent fran said polar column passes through said 13X MSCOT column and said mixed binary phase column is connected to said polar column such that at least a portion of the effluent from said polar column passes through said mixed binary phase column and such that in said second position the flow through said polar column is reversed, said polar column is connected to said first end of said nonpolar stationary column such that the flow from said polar column enters said first end of said nonpolar stationary column, said first end of said 13X MSCOT column is connected to said second gas supply means, and said first end of said mixed binary phase column is connected to said third gas supply means. The method of the present invention of analyzing a hydrocarbon sample comprising paraffins, naphthenes and aranatics, is characterized by the steps of: injecting a hydrocarbon sample into a first stream of carrier gas; passing the first stream of carrier gas and sample through a polar column having a material for retarding aranatics fran the remainder of the sample; retarding in the polar column the arcknatics from the sample and allowing the remainder of the sample and the first stream of carrier gas to pass through thereby providing a first effluent from the polar column; splitting the first effluent from the polar column into at least first and second portions; passing the first effluent portion through a 13X molecular sieve coated open tubular column (13X MSOCT column) having a layer comprising a plurality of disunited particles of 13X material disposed on an inner surface of the column by filling the column with a suspension comprising a dispersive liquid and 13X material and flawing an inert gas through the column thereby leaving a layer comprising a plurality of disunited particles of the 13X material attached to the inner surface of the column for separating paraffins and naphthenes by carbon number; passing the second effluent portion through a mixed binary phase column having a material for separating the second effluent portion by components from C1 throughf at least C8; separating in said mixed binary phase column the second effluent portion by components from C1 through at least C8; reversing the flow of said first stream of carrier gas through said polar column to remove the arcomatics fran the polar column thereby providing a second effluent from the polar column; passing the second effluent through a nonpolar stationary phase column having a material for separating the aranatics; separating in said nonpolar stationary phase column the aranatics from the second effluent; providing a second stream of carrier gas to the 13X MSCOT column; providing a third stream of carrier gas to the mixed binary phase column; modifying the temperature of the 13X MSOOT column; modifying the temperature of the nonpolar stationary phase column; detecting the amounts of paraffins and naphthenes separated by carbon number fray said sample in said 13X MSCOT column; detecting the amounts of components fran C1 through at least C8 separated fran said sample in said mixed binary phase column; and detecting the amounts of aromatic separated from said sample in said nonpolar stationary phase column. The apparatus and method of the present invention provide a detailed analysis in approximately two hours of the paraffin, naahthene and aromatic breakdown of a hydrocarbon sample boiling below 255 CC, including the C5/C6 ring naphthenes distribution. The data provided by the present invention can be used, for example, for inputting to a plant model to determine the steps that are necessary to optimize the reforming process. A plurality of columns and detectors are used concurrently to expand the analyzer's scope and to shorten the analysis tune. In an alternative embodiment, the present invention can be provided with means for splitting the sample before it is passed through the polar column. A portion of the sample is provided to a column having a material for separating a predetermined inorganic can peeent of the sample and means for detecting the amount of such conoorent separated by the column. The e present invention will now be described in more detail by way of example with reference to the accompanying drawings, in which: Fig. 1 represents a diagrammatic view of a reformer process analyzer according to the present invention; Fig. 1A represents a detail of the analyzer of Fig. 1; Fig. 2 represents a chromatogram of the component by comer ponent separation of a typical hydrocarbon sample on the mixed binary phase column; Fig. 3 represents a chromatogram of the paraffin-naphthene separation of a typical hydrocarbon sample on the 13X MASCOT column; ; Fig. 4 represents a chrrratogram showing the separation of the aranatics fran a typical hydrocarbon sample on the nonpolar stationary phase column; Fig. 5 represents an alternative entcdiment of the present invention. Referring now to Fig. 1 an embodiment of the chromatographic analyzer of the present invention is illustrated. The analyzer has a valve 10 which has twelve ports labelled 11 through 22. The valve 10 has two positions in which the ports are connected internally in different configurations. When the valve 10 is in the first position the port 13 is connected to the port 15, the port 14 is connected to the port 16, the port 17 is connected to the port 19, the port 18 is connected to the port 20, the port 21 is connected to the port 22, and the ports 11 and 12 are not connected to any of the other ports. When the valve 10 is switched to the second position as illustrated in Fig. lA, the port 11 is connected to the port 13, the port 12 is connected to the port 14, the port 15 is connected to the port 17, the port 16 is connected to the port 18, the port 19 is connected to the port 20 and the ports 21 and 22 are not connected to any of the other ports. The port 11 is connected to a line 26 which is adapted to be connected to an inert gas supply such as helium. The port 12 is connected to a line 28 which is adapted to be connected to an inert gas supply, such as helium. The port 13 is connected to a port 30 of a valve 32 by a line 34. The port 14 is connected to one side of a 13X MSOOT column 36 by a line 38. The port 15 is connected by a line 37 to a flow restrictor 40. The other end of the flow restrictor 40 is connected to a port 41 of a splitter 42 by a line 39. The port 43 of a splitter 42 is connected to the port 16 of the valve 10 by a line 45. The port 17 is connected to the parallel combination of the valves 44 and 46 by a line 48. The e other end of the valve 44 is connected to the line 26 by a line 50, and the other end of the valve 46 is connected to the line 28 by a line 52. The port 18 is connected to a sample injector 54 by a line 56. A line 58 which is adapted to be connected to an inert gas supply, such as helium or argon, is connected to the injector 54 which can be either a manual or automatic injector. In an advantageous embodiment the injector 54 has a glass liner to rnze decomposition and adscrpticn of sensitive materials of the sample on the bat metal surface of the injector. The port 19 is connected to a port 59 of a splitter 60 by a line 62. The port 20 is connected to one end of a polar column 64 by a line 66. The port 21 is connected to a port 67 of the splitter 42 by a line 68. The port 22 is vented to atmosphere by a line 70. The column 36 is a 13X molecular sieve coated open tzar column. Finely grand 13X molecular sieve material is combined with water to form a slurry which is pressured through a clean length of stainless steel capillary tdbing. A purge is madrtained to dry the column, thereby leaving the 13X sieve particles attached to the wall of the tdbing. The finely divided particle layer provides a high resolution, type separation of naphthenes, iso-paraffins and paraffins boiling up to 255 OC. A suspension of the 13X particles in the water can be achieved by means of stirring or vibrating the slurry. Usually, a treatment of two or three minutes is sufficient if no additional cartinution of the solid is desired. Before the slurry or suspension is pressed into the capillary tube, it is advantageous to pass it through a pressure sieve in order to eliminate coarser agglomerates which could lead to clogging of the capillary tube. An advantageous manner of separating the desired sized particles is to allow the larger particles to settle during a predetermined tine interval in the range of 30-120 minutes. One half to two-thirds of the upper portion of the slurry is then pipetted into a separate container. The capillary is filled by means of a pressure vessel and an inert gas, such as nitrogen, helium, argon and so forth. The pressure to be used depends on the diameter and the length of the capillary and on the viscosity of the suspension; usually the pressure is between 4-12 psig. The capillary tube should be cleansed from impurities by washing it thoroughly, such as by using 0.1-0.3 N HC1 followed by water which is followed by acetone and finally water again, prior to filling. The purging of the tube is performed by flowing an inert gas, such as helium, through the tube to dry it thereby leaving a layer of disunited 13X particles attached to the inner surface or wall of the tube. Usaally a purge of 0.1-1 ml/min is maintained for apprcximately two to five hours to dry the tube. Next, the column is stabilized at 420-440 C for about twice as long as the drying period. In an advantagesus embodiment the tube consists of 15 metres of a stainless steel capillary tube with an inner diameter of 0.5 millimetres and contains approximately 1 mg of 13X molecular sieve material having a particle size in the range of 0.4-12.0 microns. One end of the column 36 is connected to the port 14 of the valve 10 by the line 38, and the other end is connected to a flame ionization detector 72 by a line 74. The column 36 is positioned in a temperature programuble oven 76 which is indicated by dotted lines. The temperature of the oven 76 can be programmed by, for example, a suitable catter/controller, to provide suitable heating of the column 36. The column 78 is a mixed binary phase column for separating the sample by components fraa C1 through at least C8. Generally, the C9+ materials are backflushed by the valve 32. In an advantageous embodiment, the column 78 is an n-hexadecane/Fluorolube Oil LG-160 (FLO) capillary column having a film thickness of approximately 0.7 micrometres and is made of 30 metres of stainless steel capillary tubing hawing an inside diameter of 0.25 niiilimtres. An advantageous concentration is 4.35 parts of n-hexadecane and 1 part FLO by volume. The column 78 is positicned in an isothermal oven 80 which is maintained at a temperature of, for 1e, 18.5 OC, One end of the column 78 is connected to a port 82 of the valve 32 by a line 81, and the other end of the column 78 is connected to a port 84 of the valve 32 by a line 83. The port 86 of the valve 32 is connected to a flame jalization detector 88 by a line 90. The valve 32 has two position in which the ports are connected internally in different configurations. In the first position the ports 30 and 82 are connected and the ports 84 and 86 are connected. In the second position, as indicated by the dotted lines, the ports 30 and 84 are connected, and the ports 82 and 86 are connected. Switching the valve 32 fran one position to the other reverses the flow through the column 78. The column 64 is a polar column for separating the aromatics fan the reminder of the sample In an advantageous embodiment the column 64 is a stainless steel tube having a length of 60 centimetres and an inside diameter of 2.3 millimetres, with BC-120 stationary phase, on Chromosorb-P AW Dimethylchlorosilane to make the saturates fran ammatic separation. The mesh particle size is 100/120 ML One end of the column 64 is connected to the port 20 of the valve 10 by a line 66, and the other end of the column 64 is connected to the port 92 of the splitter 42 by a line 94. The column 64 is positioned in the oven 65, which is indicated by dotted lines, and is maintained at a constant temperature. The column 96 is a nonpolar stationary phase column for separating the aromatics in the sample. In an advantageous embodiment the column 96 is a stainless steel support coated open polar column having a length of 30 metres and an inside diameter of 0.5 millimetres which uses squalane for the separation. One end of the column 96 is connected to the port 98 of the splitter 60 by a line 100, and the other end of the column 96 is connected to the flame ionization detector 102 by a line 104. The column 96 is located in a temperature programmable oven 106 which is indicated by dotted lines. The temperature of the oven 106 is varied during the analysis. If desired, the columns 64 and 96 can be located in the same oven. The e splitter 60 has an additional port 108 which is vented to atmosphere; the port 108 can include a flow restrictor to limit the flow to atmosphere. The flame ionization detectors 72, 88 and 102 can include chart recorders and/or electronic circuitry to provide a signal suitable for inputting to a computer/controller. The operation of the analyzer, including the operation of the valves, the temperature programming of the ovens, and the output recording from the detectors, can be under the control of a master computer/controller. This master catputer/con- troller can also include functions for data manipulation and output formatting, such as the calculation of the paraffins, naphthenes and aromatics and the C5/C6 ring napthenes distribution as is known in the art. The operation of the reformer process analyzer of the present invention can be described as follows. The sample is injected into the analyzer by the injector 54. The carrier gas flow from the line 58 carries the sample from the injector 54 through the line 56 to the port 18 of the valve 10. The sample then passes from the port 18 to the port 20 from which it passes through the line 66 to the column 64. The column 64 retards the aramaics of the sample and allows the remainder of the sample and carrier gas to pass through to the line 94. The line 94 provides the remainder of the sample to the port 92 of the splitter 42. The splitter 42 splits the remainder of the sample three ways such that one portion Passes through the port 43 of the splitter 42, through the line 45 to the port 16 of the valve 10 to the port 14 fran which it passes through the line 38 to the column 36. A second portion of the sample passes through the port 67 of the splitter 42 to the line 68 which is connected to the port 21 of the valve 10. The sample passes fran the port 21 to the port 22 fran which it is exhausted to atmosphere by the line 70. The third portion of the sample passes through the port 41 of the splitter 42, the line 39, the restrictor 40 to the line 37. The sample passes through the line 37 to the port 15 of the valve 10 and is exhausted therefrom by the port 13 to the line 34. sattle passes through the line 34 to the port 30 of the valve 32 and is exhausted therefran at the port 82 into the line 81 and hence the column 78. The sample passes through the column 78, and the effluent fran the column 78 passes through the line 83 to the valve 30 at the port 84 and is exhausted therefran at the port 86 into the line 90 to the flame ionization dectUr 88. he carrier gas fran the lines 26 and 28 flows into the line 50 and the valve 44 and the line 52 and the valve 46 respectively. The combined flow then passes ough the line 48 to the port 17 and is exhausted from the valve 10 at the port 19. The line 62 provides the carrier gas to the port 59 of the splitter 60. A portion of the carrier gas is exhausted to atmosphere by the line 108 and the remainder passes through the port 98 of the splitter 60 to the line 100. Fran the line 100 the carrier gas passes through the column 96, thus purging it, and passes through the line 104 to the flame ionization detector 102. Before the valve 10 is switched fran its first position the valves 44 and 46 are closed in a predetermined tine sequence to raise the carrier gas pressure slightly, 2-5 psi, above roroal cQerating pressures in the lines 26 and 28 after the valve 10 is switched to its second position. This increased pressure prevents diffusing of the sample fran the columns 36 and 78 into the lines 38 and 81 respectively. For optimum separation two different molecular weight carrier gases should be used, such as argon in the line 58 and helium in the lines 26 and 28. Before benzene would elute from the column 64, the valve 10 is switched fran its first position to its second position which is indicated in Figure 1A. Carrier gas is supplied by the line 26 to the port 11 of the valve 10 and exhausted fran the valve 10 at the port 13 into the line 34. Fran the line 34 the carrier gas passes through the port 30 of the valve 32 and is exhausted therefrom at the port 82 into the line 81 and then the column 78. The carrier gas flows through the column 78 into the port 84 of the valve 32 and is exhausted therefrom at the port 86 into the line 90 fran which it is provided to the flame ionization detector 88. The column 78 separates the sample by components fram C1 through at least C8 as detected by the flame ionization detector 88. The component separation of the sample as detected by the flame ionization detector 88 is indicated in Fig. 2. The peaks identified in Fig. 2 are defined in Table 1. The horizontal axis of Fig. 2 represents tine. The arrow "A" in Fig. 2 represents backflush. STABLE 1 Identification of Chromatogram (Figure 2) Peak Number Compound 1 Butanes and Tighter 2 Isopentane 3 n-Pentane 4 2,2-Dimethylbutane 5 Cyclopentane 6 2,3-Dimethylbutane 7 2-Methylpentane 8 3-Methylpentane 9 n-Hexane 10 Methylcyclopentane 11 2,2-Dimethylpentane 12 2,4-Dimethylpentane 13 2,2,3-Trimethylbutane 14 Benzene 15 Cyclohexane 16 3,3-Dimethylpentane 17 1,1-Dimethylcylopentane 18 2-Methylhexane + 2,3-dimethylpentane 19 1,cis-3-Dimethylcyclopentane 20 3-Methylhexane 21 1,trans-3-Dimethylcyclopentane 22 1,trans-2-Dimethylcyclopentane 23 3-Ethylpentane 24 2,2,4-Trimethylpentane 25 n-Heptane 26 1,cis-2-Dimethylcyclopentane TABLE 1 (Cont. ) Identification of Chromatogram (Figure 2) Peak Number Compound 27 Methy lcyc lohexane 28 1,1,3-Trimethylcyclopentane 29 2,2-Dimethylhexane 30 Ethylcyclopentane 31 2,5-Dimethylhexane 32 2,4-Dimethylhexane + 2,2,3-trimethylpentane 33 1,trans-2,cis-4-Trimethylcyclopentane 34 1,trans-2,cis-3-Trimethylcyclopentane 35 2,3,4-Trimethylpentane 36 1,1,2-Trimethylcyclopentane 37 2-Methyl-3-ethylpentane 38 2,3-Dimethylhexane 39 1,cis-2,trans-4-Trimethylcyclopentane 40 1,cis-2,trans-3-Trimethylcyclopentane 41 1,cis-2,cis-4-Trimethylcyclopentane + 2-methylheptane + 3-methyl-3-ethylpentane + 3,4-dimethylhexane 42 4-methylheptane 43 3-Ethylhexane 44 3-Methylheptane + 1, l-dimethylcyclohexane 45 1, trans-4-Dirnettylcyclohexane + 1,cis-3-dimethylcyclohexane 46 1-Methyl-cis-3-ethylcyclopentane 47 1-Methyl-trans-3-ethylcycloipentane + l-methyl- trans-2-ethylcyclopentane + 1 -methyl-1 ethy lcyc lopentane 48 1,cis-2,cis-3-Trimethylcyclopentane + 1,trans 2-dimethylcyclohexane TABLE 1 (Cont. ) Identification of Chromatogram (Figure 2) Peak 49 1,trans-3-Dimethylcyclohexane + 1,cis-4 dimethylcyclohexane 50 C8 Paraffin 51 Isopropylcyclopentane 52 n-Octane 53 C8 Paraffin 54 1-Methyl-cis-2-ethylcyclopentane 55 C8 Paraffin 56 1,cis-2-Dimethylcyclohexane 57 C8 Paraffin 58 Ethylcyclohexane 59 n-Propylcyclopentane 60 C8 Paraffin 61 C8 Paraffin 62 C9+ Saturates Carrier gas flows fran the line 28 into the port 12 of the valve 10 and is exhausted therefrom at the port 14 into the line 38 which provides it to one end of the column 36. The e carrier gas passes through the column 36 and is exhausted therefran to the line 74 from which it is provided to the flame ionization detector 72. At the point at which the valve 10 is switched fircm the first position to its second position the oven 76 begins its temperature program. The column 36 separates the paraffins and naphthenes in the sample by carbon number as detected by the flame ionization detector 72. Fig. 3 is a typical chromatogram of the separation provided by the column 36. Carrier gas conteeues to flow through the line 38, the injector 54, the line 56 and the port 18 of the valve 10. The gas is exhausted fran the port 16 of the valve 10 into the line 45 fran which it enters the port 43 of the splitter 42. In addition, carrier gas from the lines 26 and 28 passes through the line 50 and the valve 44 and the line 52 and the valve 46 respectively to the line 48 fran which it enters the port 17 of the valve 10. The carrier gas is exhausted from the valve 10 at the port 15 through the line 37 to the flow restrictor 40 fran which it flows through the line 39 into the port 41 of the splitter 42. The combined carrier gases then flow through the port 92 of the splitter 42 into the line 94 to the column 64. It should be noted that this flow is in the opposite direction of the flow through the column 64 when the valve 10 is in its first position; this reversed flow blackflushes the aramaics that were retarded by the column 64 during the time that the sample was injected when the valve 10 was in its first position. The flow backflushes the aranatics fran the column 64 into the line 66 to the port 20 of the valve 10 and is exhausted therefran at the port 19 into the line 62. The line 62 provides the flow to the port 59 of the splitter 60 which then splits a portion of this flow to atmosphere by way of the line 108 and passes the remainder through the port 98 into the line 100. The line 100 provides the flaw to the column 96 which separates the aromatic as detected by the flame ionization detector 102 which is connected to the column 96 by the line 104. When the valve 10 is switched fan its first position to its second position the oven 106 is progressed through its temr perature program. The sample chraMtogram obtained with the column 96 is provided in Fig. 4. The horizontal axis represents time (in min). Peak A represents benzene, peak B represents toluene, peaks C represent C8 aranatics and peaks D represent C9+ aranatics. At a predetermined time the valve 30 is switched from it first position to its second position so that the flaw through the column 78 is reversed to backflush the column 78. Referring to Fig. 5, an alternative embodiment of the present invention is provided in which an additional branch for detecting an inorganic ccnpcnent of the sample is incorporated with the paraffin, naphthene and aromatic analysis scheme described in reference to Fig. 1. A 6-port valve 120 has ports 122, 124, 126, 128, 130 and 132. When the valve 120 is in its first position the port 122 is connected to the port 128, the port 124 is connected to the port 126 and the port 130 is connected to the port 132. When the valve 120 is in its second position the port 122 is connected to the port 124, the port 126 is connected to the port 132 and the port 128 is connected to the port 130. The port 122 is connected to a line 134 which is adapted for providing a gas sample to the analyzer system. The port 124 is connected to a line 136 which is vented to atmosphere, A variable sample locp 138 is connected across the ports 126 and 128. The port 132 is connected to the injector 54 by a line 140. The injector 54 is the same injector as described hereinabove in reference to Fig. 1, and again it is provided with a carrier gas, such as helium or argon by the line 58. The port 130 is connected by a line 142 to the port 144 of the splitter 146. The port 148 of the splitter 146 is connected to the line 56 which carries a portion of the sample to the port 18 of the valve 10 for analysis as described hereinabcve in reference to Fig. 1. The other portion of the sample passes through the port 150 of the splitter 146 through a flaw resistor 152 into the port 154 of the valve 155. The valve 155 is a 6-port valve having ports 154, 156, 158, 160, 162 and 164. When the valve 155 is in its first position the port 154 is connected to the port 160, the port 156 is connected to the port 158 and the port 162 is ccnnesbed to the port 164. When the valve 155 is in its second position the port 154 is connected to the port 160 is connected to the port 162 and the part 158 is connected to the port 164. The port 156 is connected to the detector 168 which can be, for example, a thermal ounductivity detector for detecting a parti cular inorganic catpnent of the sample. The column 166 which can be located in an oven 167 is connected across the ports 158 and 160. The port 162 is connected to the line 163 is vented to atmosphere. The port 164 is connected to a valve 174 through a flow restrictor 176. The e line 170 which is adapted to be connected to a gas supply means, such as argon, provides gas to both the valve 174 and the flow controller 172. The flow controller 172 provides a reference gas to the detector 168. In this emDcdiment the valve 120 allows the selection of either a liquid sample injected by the injector 54 or a gas sample provided by the line 134. The flow restrictor 152 is sized to provide the appropriate flow to the column 166. The valve 155 allows the flow through the column 166 to be reversed to backflush the column 166, thereby shortening the analysis tine. The flow restrictor 176 modifies the flow to the proper amount for the column 166 during backflushing. The valve 174 is interlocked with the valve 155 so that the valve 174 is closed when the valve 155 is in its first position and the valve 174 is open when the valve 155 is in its second position. If desired the valve 174 and the flow restrictor 176 can be omitted and the valve 155 can be replaced by a four port valve. Various modifications of the present invention will become apparent to those skilled in the art fran the foregoing description and accompanying drawings. Such modifications are intended to fall within the scope of the appended claims.

Claims: CLAIMS 1. An apparatus for analyzing a hydrocarbon sample comprising paraffins, naphthenes and aromatic, characterized by: means for providing a sample; a first means for supplying gas connected to said sample providing means, a first valve means connected to said sample providing means; a polar column connected to said first valve means for retarding the aromatic of said smnple while the remainder passes through; a 13X molecular sieve coated open tubular column (13X MSCOT column} comprising an elongated capillary tube and a layer comprising a plurality of disunited particles of 13X material disposed on the inner surface of the tube by filling the tube with a suspension comprising a dispersive liquid and 13X materials and flowing an inert gas through the tube to dry the tube thereby leaving said layer attached to the inner surface of said tube for separating the paraffins and naphthenes in said sample by carbon number, said 13X MASCOT column having a first end connected to said first valve means and a second end connected to means for determining the amounts of paraffins and naphthenes separated by carbon <RTI ID=18.13> number by said 13X MSCOT column; means for varying the temperature of said 13X MSCOr column; a mixed binary phase column for separating said sample by components from C1 through at least C8, said mixed binary phase column having a first end connected to said first valve means and a second end connoted to means for determining the arrounts of said sample separated by components from C1 through at least C8 by said mixed binary phase column; means for maintaining said mixed binary phase column at a predetermined temperature; a ncnpolar stationery phase column for separating the aromatics in said sample, said nonpolar stationary phase column having a first end connected to said first valve means and a second end connected to means for determining the amounts of said aratatics separated by said nonpolar stationary phase column; means for varying the temperature of said nonpolar stationary phase column; a send means for supplying gas connected to said first valve TreanS; a third means for supplying gas connected to said first valve means; said first valve means having at least a first and second position, such that in said first position, said polar column is connected to said injecting means, said 13X MSCOr column is connected to said polar column such that a portion of the effluent fran said polar column passes through said 13X MSCOT column and said mixed binary phase column is connected to said polar column such that at least a portion of the effluent from said polar column passes through said mixed binary phase column and such that in said second position the flow through said polar column is reversed, said polar column is connected to said first end of said nonpolar stationary column such that the flow from said polar column enters said first end of said nonpolar stationary column, said first end of said 13X MSCOr column is connected to said second gas supply means, and said first end of said mixed binary phase column is connected to said third gas supply means. 2. The apparatus as claimed in claim 1, characterized in that said apparatus further comprises a second valve means connected to said first valve means and said mixed binary phase column, said second valve means having first and second positions such that in said first position said first end of said mixed binary phase column is connected to said first valve means and said second end is connected to said means for determining the amounts of said sample separated by components from C1 through at least C8 by said mixed binary phase column and such that in said second position said second end of said mixed binary phase column is connected to said first valve means and said first end of said mixed binary phase column is connected to said means for deter <RTI ID=19.15> mining the arrcutnts of said sample separated by caponents from C1 through at least C8 by said mixed binary phase column. 3. An apparatus as claimed in claim 1, characterized in that said apparatus further comprises means to switch said first valve means from said first position to said second position at a predetermined time based an the elation tine of benzene. 4. The apparatus as claimed in claim 1, characterized in that said apparatus further comprises means connected to said sample providing means for separating a portion of the sample, a fourth column connected to said separating means for separating a prer determined inorganic component fram the sample and means for determining the amount of said predetermined inorganic component separated fran said sample by said fourth column. 5. The e apparatus as claimed in claim 4, characterized in that said sarge providing means is adapted to provide a liquid sample and wherein said apparatus further comprises means adapted for providing a gas sample and a third valve means connected to said splitting means and said liquid sample providing means, said third valve means having at least a first and second position such that in said first position said liquid sample providing means is connected to said splitting means and said means for providing a gas sample is not connected to said splitting means and such that in said second position said means for providing a gas sample is connected to said splitting means and said means for providing a liquid sample is not connected to said splitting means. 6. The apparatus as claimed in claim 5, characterized in that said apparatus further comprises a fourth valve means connected to said fourth column, said fourth valve means having a first position in which flow is directed through said fourth column in a first direction and a second position in which flow is directed through said fourth column in the apposite direction. 7. The apparatus as claieed in claim 1, characterized in that said apparatus further comprises a fifth valve means having a first end connected to said second means for supplying gas and a second end connected to said first valve means and a sixth valve means having a first end connected to said third gas supply means and a second end connected to said first valve means, said first valve means being adapted such that said fifth and sixth valve means are connected to said nonpolar stationary phase column when said first valve means is in its first position, said fifth and sixth valve means being adapted to be open when said first valve means is in its first position and being adapted to be closed at a predetermined time before said first valve means is switched to said second position. 8. A method of analyzing a hydrocarbon sample ccoprising paraffins, naphthenes and aranatics, characterized by the steps of: injecting a hydrocaron sample into a first stream of carrier gas; passing the first stream of carrier gas and sample through a polar column having a material for retarding arrratics from the remainder of the sample; retarding in the polar column the aranatics fran the sample and allowing the remainder of the sample and the first stream of carrier gas to pass through thereby providing a first effluent fran the polar column; splitting the first effluent fran the polar column into at least first and second portions; passing the first effluent portion through a 13X molecular sieve coated open polar column (13X MSCOT column) having a layer oamprising a plurality of dis- united particles of 13X material disposed on an inner surface of the column by filling the column with a suspension comprising a dispersive liquid and 13X material and flowing an inert gas through the column thereby leaving a layer comprising a plurality of disunited particles of the 13X material attached to the inner surface of the column for separating paraffins and naphthenes by carbon number; passing the second effluent portion through a mixed binary phase column having a material for separating the second effluent portion by components fran C1 through at least C8; separating in said mixed binary phase column the second effluent portion by components fran C1 through at least C8; reversing the flow of said first stream of carrier gas through said polar column to remove the aromatics from the polar column thereby providing a second effluent from the polar column; passing the second effluent through a nonpolar stationary phase column having a material for separating the aranatics; separating in said nonpolar stationary phase column the aromatics fran the second effluent; providing a second stream of carrier gas to the 13X MSCOT column; providing a third stream of carrier gas to the mixed binary phase column; modifying the temperature of the 13X MSCOT column; modifying the temperature of the nonpolar stationary phase column; detecting the of paraffins and naphthenes separated by carbon number fran said sample in said 13X MSCOT column; detecting the amounts of components fan C1 through at least C8 separated fran said sample in said mixed binary phase column; ; and detecting the amounts of aromatics separated from said sample in said nonpolar stationary phase column. 9. The method as claimed in claim 8, characterized in that said step of reversing the flow of said first stream of carrier gas through said polar column is performed at a predetermined tie related to the elution time of benzene. 10. The method as claeeed in claim 8, chaacterized by the step of reversing the flow through said mixed binary phase coliitri at a predetermined time after the detection of components of said sample from C1 through at least C8. 11. The method as claimed in claim 8, characterized by the steps of: splitting said sample before passing it through said polar column; passing a portion of said split sample through a first column containing a material for separating a predetermined inorganic component fran said split sample; separating said predetermined inorganic component in said first column; and detecting the amount of said predetermined inorganic component separated fran said portion of the split sample in said first colurtn. 12. The method as claimed in claim 8, characterized by the Step of reversing the flow through said first column at a predetermined time, 13. The method as claimed in claim 8, characterized by the step of flowing a gas through said nonpolar stationary phase column until a predetermined period of time before reversing the flow of said first stream of carrier gas through said polar column.

Inventors: ROBINSON, ROBERT EUGENE, SZAKASITS, JULIUS JOZSEF
Applicants: SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V.
Application year: 1984
Main classification: G01N33
IPC codes: G01N30, G01N33