石油中硫化物检测方案(气相色谱仪)

智能文字提取功能测试中

SCICM|NSTRUMENTS Analysis of Sulphur Compounds in Various LiquefiedPetroleum Gases INTRODUCTION The low-level analysis of sulphur containing componentssuch as Hydrogen Sulphide (H，S)， cos (carbonyl sulphide)and mercaptans， in liquified petroleum gas (LPG)， ischallenging. First of all， the system has to be inert；stainless steel adsorbs H，S and other sulphur containingcomponents. Secondly， the column used must be able toseparate the components of interest. Although a highlyselective pulsed flame photometric detector (PFPD) is usedin sulphur mode， the bulk hydrocarbons tends to quenchthe PFPD signal. EXPERIMENTAL The LPG type samples are injected as a gas via two gassampling valves， in series. A micro-gasifier in front of theinjection valves ensures a fully gaseous sample state. Thecomplete sample path is Ultimetal deactivated ensuringan inert system preventing adsorption of the sulphurcomponents. If the bulk sample is mainly propane， H，S is analysed onthe non-polar column from Channel A. The COS is analysedon the BOND Qcolumn from channel B. The mercaptanscan beanalysed on both columns. However， if the bulkis mainly butane， the methyl mercaptan is analysed onBOND Q from channel B as it co-elutes with butane on thenon-polar column of channel A. Analytical parameters ofthe analysis can be found in table 1. SCION Instruments developed a two-channel configurationfor this analysis with both channels being equipped with aPFPD， as shown in Figure 1. Fig 1. Schematic for the two-channel system Sample loop 100pL ChannelA 220℃， Split 1：30 ChannelB 220℃， Split 1：20 Oven 35℃，12C/min to 250℃ (1.25min) Column A SCION-5. 30m x0.32mm X5um Column B BOND Q 25m x 0.32mm Carrier Helium， 2mL/min PFPD 200℃ Air1 & 2 17mL/min，10mL/min H2 13mL/min Samples includeda：sulphur calibration standardinnitrogen. Bulk analysis was also performed on propane andbutane RESULTS To validate the performance of the system， a calibrationmixture was used. It is vital that the nitrogen must notquench either channel for sulphur components. Figures2 and 3 show the chromatograms from the calibrationstandard on both channels， The non-polar column from channel A shows co-elution ofpropane and COS. H，S and the mercaptans are very wellresolved and perfectly placed for quantification. Figures 4shows the chromatogram of the bulk propane analysis onchannel A. Fig 2. Sulphur components in calibration standard-non-polar Fig 3. Sulphur components in calibration standard-BOND Q Fig 4. Sulphurcomponents in propane-non polar Fig 5. Sulphur components in propane -BOND Q Analysis ofsulphur components in bulk butane can be foundin Figures 6 and 7. On the non-polar column in channel A，the bulk butane co-elutes with methyl mercaptan causingquenching of the PFPD. Methyl mercaptan is thereforeanalysed on the BOND Q column， on channel B. Fig 7. Sulphur components in propane -BONDQ The calibration mixture was analysed 15 times for validation.The validation data can be found in Tables 2 and 3. in theappendix. Figures 8 shows the repeatability from channelA. Fig 8. Repeatability data from channelA CONCLUSION The custom configured SCION 456 GC offers numerousbenefits for the analysis of sulphur components in LPG. Themicro-gasifier enables the direct coupling of an LPG streamto the GC， eliminating the need for sample pre-treatment.The Ultimetal sample path ensures a trouble-free analysisof sulphur containing components at low concentrations.Increased flexibility with regard to the different samplesis achieved via a two-channel approach. Two differentcolumns， each equipped with a PFPD detector， ensuresexcellent separation independent of the bulk componentsto analyse H2S， COS and mercaptans. Repeatability datashows that the system is perfectly suited for the analysis ofthese low level， sulphur containing components. Table 2.. Repeatability data ofchannelA Run H2S COS MeSH EtSG i-propSH n-propSH 1 1215606 918906 327886 294361 404068 633667 2 1254247 935746 328676 298754 425778 628584 3 1239701 943248 332392 300742 419173 646792 4 1274378 948168 335003 296093 425080 617068 5 1243905 924324 339181 299545 426836 618302 6 1285376 937870 338153 299489 433643 648998 7 1228259 964881 335009 298247 424477 623804 8 1291766 939709 335747 299883 413521 625520 9 1275770 964140 341016 302965 437842 651128 10 1278718 979071 341823 299995 430574 641596 11 1273792 970358 335827 305986 432967 638665 12 1236414 949312 330520 297651 434679 655549 13 1235316 919577 329219 291021 423661 632948 14 1225871 908744 322353 292467 415695 661764 15 1237259 926690 320472 289776 416298 662962 Ave 1253092 942050 332885 297786 424298 639156 Std Dev 24587 20763 6360 4406 9218 15062 RSD% 2.0 2.2 1.9 1.5 2.2 2.4 Table 3. Repeatability data of channel Run H2S COS MeSH EtSG i-propSH n-propSH 1 54562 687805 827495 1594184 1424799 1628308 2 538184 677330 824772 1583903 1439569 1642325 3 532203 693217 846290 1612155 1463529 1634377 4 544055 703604 839709 1596015 1466332 1658115 5 548043 702749 843958 1588910 1433280 1641332 6 542476 695695 847346 1601313 1494175 1672709 7 552342 713601 856817 1665891 1532625 1706860 8 538959 702750 844759 1629822 1461748 1667079 9 541759 697077 850350 1633218 1489508 1678310 10 518534 699979 844822 1617188 1494334 1665749 11 538677 684485 829601 1574632 1430748 1651976 12 525475 702033 840280 1613474 1498361 1691346 13 525827 708639 834848 1573162 1491257 1648297 14 521071 711786 830656 1615305 1457386 1634290 15 518329 702762 833949 1605378 1446365 1633789 Ave 535426 698901 839710 1606970 1468268 1656991 Std Dev 11104 9988 9223 24335 30926 15062 RSD% 2.1 1.4 1.1 1.5 2.1 2.4 这台定制的赛里安456GC对LPG中的硫化物分析有数不尽的好处。微型气化装置能使LPG直接导入GC，无需样品预处理。Ultimetal样品通道确保含有低浓度硫化物的样品分析无故障进行。对于不同的样品通过此双通道方法增加了灵活性。2根不同的色谱柱每根都接一个PFPD检测器确保不受样品基质的影响极好的将H2S，COS和甲硫醇分离。重复性数据显示系统完美适合于这些低浓度硫化物的分析。