Article pubs.acs.org/EF
Simultaneous Determination of Hydrocarbon, Nitrogen, Sulfur, and Their Boiling Range Distribution in Vacuum Gas Oil Using a High Temperature CNS-SimDis Analyzer Ramachandra Chakravarthy,† Anilkumar Savalia,† Sudhir Kulkarni,† Ganesh N. Naik,† Unnikrishnan Sridharan,† Chandra Saravanan,† Asit Kumar Das,† and Kalagouda B. Gudasi*,‡ †
Reliance Industries Limited, Thane Belapur Road, Ghansoli-400701, Maharashtra, India Karnatak University, Pavate Nagar, Dharwad-580003, Karnataka, India
‡
ABSTRACT: Petroleum is a naturally occurring complex mixture containing predominantly hydrocarbons and a significant quantity of nitrogen and sulfur. Currently, no methods are available for the simultaneous determination of these components along with their boiling point distributions. Hence, a new analytical technique was developed for the quantification of petroleum components using “high temperature CNS-simulated distillation” (HT-CNS SimDis) equipped with flame ionization and chemiluminescence detectors. The method has the advantages of reporting percentage yield, percentage recovery, and total component determinations along with their boiling point distributions. Total sulfur and total nitrogen contents obtained by this technique are compared with that of the ASTM method. Presently this method is being applied for heavy petroleum fractions such as VGO samples. A new reference standard, “VGO NS reference”, was developed as a secondary standard for the quantification of sulfur and nitrogen. Requirement for less sample, accuracy, good repeatability, and speed of analyses are the key features of this technique.
1. INTRODUCTION Over the past few years, refiners have faced declining quality of crude oils which contain a large quantity of unwanted impurities such as sulfur and nitrogen.1,2 These impurities not only affect the refinery units but also cause environmental pollution.3 Making a decision on adjusting the impurity content to increase the product quality is essential to optimize the profit margin. Several methods are available in the literature for the quantification of sulfur and nitrogen,4−10 but none of them are available for simultaneous determination of hydrocarbon, nitrogen, and sulfur along with their cutwise distribution with respect to boiling points. Hence, understanding and making a quick decision regarding the nature of crude oil and its fractions is becoming a time-consuming exercise. Presently, many refineries depend on “total sulfur and total nitrogen analyzer (TSTN analyzer)” or “X-ray fluorescence (XRF)” techniques8 for the analyses of sulfur and nitrogen content present in crude oil and its fractions. But these techniques are not able to provide a distribution of the components in various boiling point ranges. Thus, these techniques have limited use in R&D units, processing units, crude oil nature prediction, catalytic processing units, etc. Hence, new technology is highly essential for the complete and quick characterization of these impurities in petroleum crude oil and its fractions. Recently, a new technique was developed for the determination of hydrocarbon and sulfur along with their boiling point distribution using a CNS SimDis analyzer.11 But this method is limited to the fractions having boiling points up to 538 °C and does not provide any information about nitrogen. Therefore, a new technique is developed for the simultaneous determination of carbon, nitrogen, and sulfur along with their distribution with © XXXX American Chemical Society
respect to boiling point using high temperature CNS SimDis. The results obtained by this method are thoroughly validated and also applied for the analyses of several VGO samples. This new technique should be promising in the future for the determination of hydrocarbon, nitrogen, and sulfur present in petroleum fractions.
2. EXPERIMENTAL SECTION 2.1. Materials and Methods. Vacuum gas oil (VGO) samples are collected from “Jamnagar Refinery Units”, Gujarat, India. The boiling point (bp) calibrant standard, reference standards such as reference 5010, lube oil, NS standard and Albian heavy, and “nitrogen and sulfur” standards for the TSTN analyzer were procured from PAC, Analytical Services, Netherlands. All the solvents were of HPLC grade with 99.9% purity obtained from Merck chemicals and used without further purification. 2.2. Instrumental Parameters. HT-CNS SimDis is a GC-based instrument with flame ionization and chemiluminescence detectors and simulated distillation features that delivers accurate and comprehensive all in one quantitative data for hydrocarbon, nitrogen, and sulfur along with their boiling point distribution. The instrumental conditions are presented in Table 1. The analyses have been performed using the software “AC Simulated Distillation” provided by PAC. A cool on-column injection technique was adopted for introducing liquid sample directly onto the GC column. This technique has several advantages: mainly it eliminates sample discrimination and sample alteration and provides high analytical precision. Maintaining the cool on-column inlet includes changing septa, cleaning inlet components, and checking and correcting leaks in the system. These parameters were maintained as per manufacturer’s application note.12 Received: February 11, 2016 Revised: March 30, 2016
A
DOI: 10.1021/acs.energyfuels.6b00339 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels Table 1. HT-CNS SimDis Instrumental Parameters instrument column flow condition inlet events detector FID NCD/SCD oven sample injection
Agilent 7890 A gas chromatograph equipped with FID, NCD, and SCD and AC Simulated Distillation software capillary 5 m, 0.53 mm ID, 0.17 μm 100% dimethylpolysiloxane stationary phase 20 mL/min helium carrier (constant flow) temperature: programmed 100 to 400°C at 25 °C/min valve on: 16 min, valve off: 21.6 min FID, NCD, SCD temperature: 430 °C, 35 mL/min H2, 350 mL/min air with He makeup temperature: 950 °C, 10 mL/min O2, 90 mL/min H2, 100−150 mL/min He makeup 40 to 430 °C, at 25 °C/min, hold time: 5 min 0.5 μL
throughout the analyses. The separation of components in the column was highly influenced by both column physical parameters and operating conditions. Although the column stationary phase was stable at elevated temperatures, some bleeding (removal of stationary phase from column) still occurs above 400 °C.11 This was monitored by calculating a parameter called skew (a measure of peak shape and resolution) at various temperatures using the boiling point calibration mixture. Skew value is a measure of deactivation of column and peak symmetry. A skew value of >1 indicates that the column condition and peak symmetry are acceptable for measurement. Samples were analyzed only after column conditions were maintained as per ASTM protocol. It is well-known that the heavier components of petroleum fractions start cracking and coking above 400 °C. As the injected sample comes in contact with front end of the column, at this temperature traces of its heavy components may get converted into coke and adsorb on the internal surface of the column. If the front end of the column is not cut over a period of time, the coke material will act as an adsorbent for the next injection. Hence, it will affect the analyses in three ways: (i) It will alter the elution profile of adsorbed components, and due to strong adsorption they will elute at higher temperature. (ii) Some of the components will not elute at all and remain stuck inside the column. (iii) The coke acts as a catalyst for further coking of the next sample. Therefore, the amount of error increases as the coke formation inside the column increases. To avoid analytical error, it is recommended to cut the front end of the column, and its performance was monitored by injecting bp calibrant and several reference standards. Column suitability and detector performance for sulfur and nitrogen were monitored by checking the equimolarity value, and it should be less than 10%. Quantitative sulfur and nitrogen standards were used to determine sulfur chemiluminescense detector (SCD) and nitrogen chemiluminescense detector (NCD) response factors on a daily basis. The column eluents were divided into three parts using a suitable splitter to accomplish the simultaneous detection of hydrocarbon (FID), sulfur (SCD), and nitrogen (NCD) components. The detector signal integral was recorded as area slices for the consecutive retention time interval during analyses. High purity helium gas (99.999%) was used as a carrier, and a combination of hydrogen and air (1:10 volume ratio) was used to generate the flame. The oven temperature was programmed at a reproducible linear rate to have good separation of the sample components. Constant laboratory temperature is recommended for improving accuracy of the analysis. 2.3. Preparations. 2.3.1. Preparation of Standards for CNS SimDis. The bp calibrant, reference 5010, and lube oil were used as per the application note to check the calibration and column performance parameters. The chemiluminescence detector performances were checked by using “NS standard and Albian heavy” reference standards. A secondary reference standard for nitrogen and sulfur quantification was prepared in house, named as “VGO NS reference”, and used in place of Albian heavy for quantification of sulfur and nitrogen. The “VGO NS reference” was prepared by dissolving approximately 100−200 mg of the “VGO NS reference” sample in 7−8 mL of an accurately weighed quantity of cyclohexane and mixed well to get a homogeneous solution. The total nitrogen and sulfur content of the “VGO NS reference” is previously known, and hence the concentration
Table 2. Comparison Data for TS and TN Using ASTM and HT-CNS SimDis Methods for “VGO NS Reference” Standard total sulfur (%)
total nitrogen (%)
replicate
ASTM
CNS SimDis
ASTM
CNS SimDis
1 2 3 4 5 6 average SD RSD (%)
2.6903 2.6654 2.6757 2.6536 2.6511 2.6338 2.6617 0.0199 0.7484
2.6711 2.6873 2.6887 2.7091 2.6886 2.6770 2.6870 0.0130 0.4843
0.0816 0.0801 0.0818 0.0832 0.0825 0.0819 0.0819 0.001 1.2667
0.0874 0.0789 0.0792 0.0815 0.0847 0.0839 0.0826 0.0033 4.0371
Figure 1. Calibration graph for sulfur quantification using the TSTN analyzer.
Figure 2. Calibration graph for nitrogen quantification using the TSTN analyzer. A nonpolar (DB-1) gas chromatographic capillary column with 100% polydimethylsiloxane (PDMS) as stationary phase was used to elute the hydrocarbon components of the sample as a function of their increasing boiling points. The column temperature was raised at a reproducible linear rate, and the area under the chromatogram was recorded B
DOI: 10.1021/acs.energyfuels.6b00339 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels
Figure 3. Boiling point distribution plot for bp calibrant. of the solution was maintained in such a way that it should not saturate the detectors. 2.3.2. Sample Preparation for CNS SimDis. Approximately 100−200 mg of the VGO samples were weighed up to 0.1 mg accuracy and dissolved in accurately weighed ∼5 g of the solvent (usually in cyclohexane/isooctane) in a 20 mL glass vial, and the resultant solution was transferred to a 2 mL GC vial and sealed with an aluminum crimp cap. This GC vial was placed on the autosampler for injection, and 0.5 μL volume of the solution was injected for analysis. A blank analysis was performed and subtracted from the sample chromatogram during calculation. 2.3.3. Preparation of Sample for TSTN Analyses. Approximately 100−200 mg of the sample was dissolved in 10 mL of cyclohexane/ isooctane/toluene and mixed well to get a homogeneous solution. The resultant solution was transferred to a 2 mL GC vial and sealed with an aluminum crimp cap of which 15 μL was used for the analysis. A blank reading was taken before running the sample for analyses. 2.4. Calibration and Validation of HT-CNS SimDis. The performance of HT-CNS SimDis instrument depends upon the separation capacity of the column as well as sensitivity of the detectors. N-Paraffin (bp calibrant) standard (C5−C90) from PAC, The Netherlands, was used to calibrate the HT-CNS SimDis instrument. The retention time of each n-paraffin component was identified and stored in the software. Two different n-paraffin calibration standards (light and heavy) were supplied in small sealed vials which were mixed before each calibration run to get boiling point distribution. Any appropriate, accurately weighed compound may be used in place of NS standard and Albian heavy, but those compounds should cover a boiling range from C5 to C90. It is not required to include every carbon number but at least sufficient points to generate a reliable calibration curve. The results obtained for calibration were compared with standard results which were preloaded in the software. Once the calibration meets the requirement for chromatographic separation, the instrument can then be used for sample analysis. The method validation was performed by comparing the CNS SimDis results of 15 VGO samples with those obtained by the TSTN analyzer as per ASTM methods. A secondary reference standard, “VGO NS reference”, for sulfur and nitrogen was selected for routine analyses and validated using Albian heavy reference standard supplied by PAC. The results obtained by CNS SimDis for “VGO NS reference” sample have been compared with results obtained as per the reference method.12 Comparison data for TS and TN using ASTM and CNS SimDis methods for “VGO NS reference” standard is presented in Table 2. 2.5. Calibration of the TSTN Analyzer. The calibration for total sulfur and total nitrogen was performed according to the reference method.12 A known concentration of sulfur and nitrogen standards were prepared in cyclohexane with different concentrations and analyzed. The calibration graph was drawn with area obtained by the
TSTN analyzer against concentration of the solution. The linearity equation obtained by the graph was used for the calculation of total sulfur and total nitrogen present in unknown samples. The blank reading was subtracted by all sample readings before processing them using Multi Tech Software. The calibration graphs for sulfur and nitrogen are presented in Figures 1 and 2, respectively.
3. RESULTS AND DISCUSSION The HT-CNS SimDis employs a unique, accurate, and precise method for the determination of hydrocarbons, nitrogen, and sulfur and their boiling range distributions. The commonly used TBP distillation is time-consuming and requires a large amount of
Figure 4. Boiling point distribution vs retention time plot for bp calibrant. C
DOI: 10.1021/acs.energyfuels.6b00339 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels
Figure 5. Hydrocarbon distribution for reference 5010.
Figure 6. Hydrocarbon distribution for reference lube oil.
Figure 7. Nitrogen signal for NS standard using NCD.
The analysis of sample using the present technique depends on several parameters such as column efficiency, equilibration time, oven temperature, sensitivity of detectors, etc.
crude samples. On the other hand, HT-SimDis can provide similar analysis very quickly with much smaller quantity of sample. The present method is well validated with several analytical steps. D
DOI: 10.1021/acs.energyfuels.6b00339 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels
Figure 8. Sulfur signal for NS standard using SCD.
Figure 9. Hydrocarbon distribution graph for Albian heavy.
Figure 10. Nitrogen distribution graph for Albian heavy.
The “boiling point distribution graph” and “comparison of boiling point distribution with retention time” for bp calibrant are presented in Figures 3 and 4, respectively. The hydrocarbon distribution for reference 5010 and lube oil are
presented in Figures 5 and 6, respectively. The calibration signal for NS standard and Albian heavy are presented in Figures 7−11, respectively. The purpose of calibration of either column E
DOI: 10.1021/acs.energyfuels.6b00339 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels
Figure 11. Sulfur distribution graph for Albian heavy.
the characteristic reaction of ozone with nitrogen and sulfur species. Even though SCD and NCD are different in various details, overall operating principles are very similar and both follow a similar detection scheme.4−11 The NCD works with the chemiluminescence reaction, which involves the characteristic NO + O3 reaction. This reaction generates distinctive broadband near-infrared chemiluminescence emission centered around 1200 nm. The reaction mechanism follows very simple steps in which nitrogen of all nitrogen-containing species burns in the presence of oxygen and ozone and emits energy in the form of radiation that is detected by the NCD. The overall reaction is described in the following steps.
Table 3. Comparison of Nitrogen and Sulfur Results Obtained by HT-CNS SimDis and the TSTN Analyzer total sulfur
total nitrogen
sample ID
TSTN analyzer
CNS SimDis
TSTN analyzer
CNS SimDis
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
4.0531 2.6294 3.1118 2.2307 0.7352 2.7289 2.6462 2.0979 1.4271 2.3836 2.7981 0.2844 1.3211 2.1867 2.3267
4.1151 2.6903 3.0961 2.2362 0.7173 2.7213 2.6487 2.0488 1.4122 2.3771 2.7228 0.2570 1.3464 2.1634 2.3423
0.1334 0.2683 0.0970 0.0993 0.3183 0.0813 0.0812 0.2502 0.1919 0.1950 0.2799 0.1949 0.1895 0.2910 0.2312
0.1300 0.2602 0.0939 0.0985 0.3051 0.0799 0.0842 0.2253 0.1884 0.1795 0.2397 0.1869 0.1894 0.2870 0.2339
R−N + O2 → NO + CO2 + H 2O
NO + O3 → NO2 * → NO2 + O2 + ℏν
Sulfur chemiluminescence utilizes the combustion of sulfur compounds to form sulfur monoxide, and subsequent reaction of “SO” with ozone forms sulfur dioxide with the elimination of energy that is detected by the SCD. The reaction proceeds as follows:
or detector is mainly to check performance of the instrument to measure hydrocarbon, sulfur, and nitrogen simultaneously. Gas-phase ozone-induced chemiluminescence reactions are the basis for detection of nitrogen and/or sulfur present in the sample. The chemiluminescent emission is generated by
R−S + O → SO + other products
SO + O3 → SO2 * → SO2 + O2 + ℏν (around 350 nm)
Table 4. Cutwise Distribution of Nitrogen in the VGO Sample bp (°C)
recovered N (ppm)
fraction N (ppm)
bp (°C)
recovered N (ppm)
fraction N (ppm)
bp (°C)
recovered N (ppm)
fraction N (ppm)
220 280 290 300 310 320 330 340 350 360 370 380 390 400 410
0.5 1.0 1.5 2.0 2.5 4.0 4.5 7.5 20.0 42.5 66.5 86.5 102.5 119.5 141.0
0.5 0.5 0.5 0.5 0.5 1.5 0.5 3.0 12.5 22.5 24.0 20.0 16.0 17.0 21.5
420 430 440 450 460 470 480 490 500 510 520 530 540 550 560
168.5 201.0 237.5 272.5 308.0 345.0 383.0 425.5 469.5 512.0 556.5 597.5 633.5 661.5 683.5
27.5 32.5 36.5 35.0 35.5 37.0 38.0 42.5 44.0 42.5 44.5 41.0 36.0 28.0 22.0
570 580 590 600 610 620 630 640 650 660 670 680 690 700
699.0 712.5 726.5 738.5 747.5 754.0 757.5 759.0 760.5 762.5 764.5 766.0 767.5 769.0
15.5 13.5 14.0 12.0 9.0 6.5 3.5 1.5 1.5 2.0 2.0 1.5 1.5 1.5
F
DOI: 10.1021/acs.energyfuels.6b00339 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels Table 5. Cutwise Distribution of Sulfur in the VGO Sample bp (°C)
recovered S (ppm)
fraction S (ppm)
bp (°C)
recovered S (ppm)
fraction S (ppm)
bp (°C)
recovered S (ppm)
fraction S (ppm)
120 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360
4.0 5.0 7.0 11.5 18.0 27.0 38.5 52.0 68.0 82.5 97.0 109.5 120.0 129.5 137.5 145.0 154.5 215.5
4.0 1.0 2.0 4.5 6.5 9.0 11.5 13.5 16.0 14.5 14.5 12.5 10.5 9.5 8.0 7.5 9.5 61.0
370 380 390 400 410 420 430 440 450 460 470 480 490 500 510 520 530 540
460.0 1008.0 1933.0 3217.5 4619.0 6183.0 7757.0 9287.0 10739.0 12222.5 13753.5 15312.0 16866.5 18441.5 19972.0 21498.0 22928.0 24177.5
244.5 548.0 925.0 1284.5 1401.5 1564.0 1574.0 1530.0 1452.0 1483.5 1531.0 1558.5 1554.5 1575.0 1530.5 1526.0 1430.0 1249.5
550 560 570 580 590 600 610 620 630 640 650 660 670 680 690 700
25160.0 25861.0 26302.5 26553.0 26693.0 26770.0 26815.5 26843.0 26862.5 26876.5 26887.5 26896.5 26903.5 26910.0 26915.5 26922.0
982.5 701.0 441.5 250.5 140.0 77.0 45.5 27.5 19.5 14.0 11.0 9.0 7.0 6.5 5.5 6.5
Table 6. Comparison Study of Boiling Point Distribution of Hydrocarbons and Percentage Recovery in VGO Samplesa VGO 1
a
VGO 2
VGO 3
VGO 4
recovery (%)
bp (°C)
recovery (%)
bp (°C)
recovery (%)
bp (°C)
recovery (%)
bp (°C)
IBP 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 FBP
259.5 332.4 358.7 376.4 390.5 401.9 412.2 421.5 430.2 438.2 446.2 454.4 463.0 471.9 481.1 491.0 501.6 513.5 527.9 548.6 602.5
IBP 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 FBP
355.9 383.9 395.4 403.5 413.9 421.2 427.2 432.7 440.4 445.9 451.6 458.4 465.4 472.6 480.6 488.9 497.6 506.9 517.8 532.8 614.3
IBP 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 FBP
250.0 316.8 343.0 359.4 373.0 384.4 394.8 404.3 413.0 421.8 430.4 438.8 447.1 455.8 465.4 475.5 487.3 500.6 517.0 542.0 606.5
IBP 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 FBP
290.7 331.2 353.4 367.9 379.7 390.6 400.2 408.7 416.6 424.1 431.9 440.1 448.0 456.3 465.3 474.9 483.4 498.9 514.8 538.5 602.5
IBP, initial boiling point; FBP, final boiling point.
ultraviolet fluorescence (UVF) and chemiluminescence technologies. Fifteen samples have been tested for the validation of CNS SimDis method for the determination of hydrocarbon, nitrogen, and sulfur, and typical chromatograms for sample 3 are presented in Figures 12−14, respectively. All the analyses were performed in triplicate, and average values have been considered for the validation. The results include boiling point distribution, percentage recovery, cutwise hydrocarbon, sulfur, and nitrogen distribution, total hydrocarbon, total nitrogen, and total sulfur. The results between the two different methods are very close to each other, which suggests that the new method is more beneficial for analyses of VGO samples. Typical graphs for
This method extends the scope of ASTM D7807-12 in various features and facilitates the analyses of petroleum distillates. 3.1. Determination of Carbon, Nitrogen, and Sulfur. The CNS SimDis method for the determination of total sulfur and total nitrogen content was validated by analyzing several VGO samples and comparing data with those obtained by standard ASTM methods using a TSTN analyzer. A comparison of results obtained by the two different methods is presented in Table 3. The representative nitrogen and sulfur cutwise distribution in the VGO sample is presented in Tables 4 and 5, respectively. The boiling point distribution and percentage recovery in four VGO samples are presented in Table 6. The TSTN analyzer works through unique processes such as G
DOI: 10.1021/acs.energyfuels.6b00339 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels
Figure 12. Typical hydrocarbon distribution graph for sample 3.
Figure 13. Typical nitrogen distribution graph for sample 3.
Figure 14. Typical sulfur distribution graph for sample 3.
VGO samples. A comparison of the two methods is presented in Table 3. These results will be highly useful for the determination of product value and to optimize process parameters or intermediate products.
nitrogen and sulfur signals obtained by the TSTN analyzer are presented in Figures 15 and 16, respectively. The distribution of all components with respect to their boiling point provides detailed information regarding the characteristics of the H
DOI: 10.1021/acs.energyfuels.6b00339 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels
Figure 15. Typical graph of the nitrogen signal for sample 6 analyzed by the TSTN analyzer.
Figure 16. Typical graph of the sulfur signal for sample 6 analyzed by the TSTN analyzer. (5) Standard Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry, ASTM D2622-10; ASTM International: West Conshohocken, PA. (6) Standard Test Method for Sulfur in Petroleum Products, ASTM D1266-13; ASTM International: West Conshohocken, PA. (7) Standard Test Method for Sulfur in Petroleum Products by Hydrogenolysis and Rateometric Colorimetry, ASTM D4045-15; ASTM International: West Conshohocken, PA. (8) Standard Test Method for Sulfur in Petroleum and Petroleum Products by Energy Dispersive X-ray Fluorescence Spectrometry, ASTM D4294-10; ASTM International: West Conshohocken, PA. (9) Standard Test Method for Trace Nitrogen in Liquid Petroleum Hydrocarbons by Syringe/Inlet Oxidative Combustion and Chemiluminescence Detection, ASTM D4629-12; ASTM International: West Conshohocken, PA. (10) Standard Test Method for Total Chemically Bound Nitrogen in Water by Pyrolysis and Chemiluminescence Detection, ASTM D5176-08; ASTM International: West Conshohocken, PA. (11) Standard Test Method for Determination of Boiling Range Distribution of Hydrocarbon and Sulfur Components of Petroleum Distillates by Gas Chromatography and Chemiluminescence Detection, ASTM D7807-12; ASTM International: West Conshohocken, PA. (12) Total Sulfur and Total Nitrogen Process Analyzer, Application Note, Multi Tech, PAC.
4. CONCLUSION The unique method for simultaneous determination of hydrocarbon, nitrogen, and sulfur using combined FID and chemiluminescence detection technology provides a broad range of applications in petroleum characterization. Single run, small sample requirement, accuracy, good repeatability, speed of analyses, and boiling range distributions of all the components are key features of this new technique. The new secondary reference standard prepared is highly economical and applicable for routine analyses.
■
AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
■
ACKNOWLEDGMENTS We are very thankful to Jamnagar Refinery Unit, Reliance Industries Ltd., Jamnagar, India, for providing VGO samples. We are also thankful to PAC, Application Laboratory, Dubai, for providing analytical support for the determination of total sulfur and total nitrogen using the TSTN analyzer.
■
REFERENCES
(1) Berger, B. D.; Anderson, K. E. Modern Petroleum, A Basic Primer of the Industry; Oil & Gas Journal Books: Houston, TX, 1978. (2) Gary, J. H.; Handwerk, G. E.; Kaiser, M. J. Petroleum Refining Technology and Economics, 5th ed.; CRC Press: Boca Raton, FL, 2007. (3) James, G. S. Environmental Analysis and Technology for the Refining Industry; John Wiley and Sons., Inc.: Hoboken, NJ, 2005; pp 1−416. (4) Standard Test Method for Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection, ASTM D5623-94; ASTM International: West Conshohocken, PA, 2014. I
DOI: 10.1021/acs.energyfuels.6b00339 Energy Fuels XXXX, XXX, XXX−XXX
