PONA Analysis on GSBP-PONA Column

PONA Analysis on GSBP-PONA Column Naizhong Zou, Beijing Chromtech Institute, Beijing, China Zack Ji, GS-Tek. Newark, DE USA 1. Introduction Gasoline, either naphtha, cracked or reformulated, contains large number of hydrocarbons including isomers. Because of complex compositions, the analysis of individual components is a challenging technique. ASTM D 5374 and D5374-92 give methods of detailed hydrocarbon analysis (DHA) for gasoline and other petrochemical applications. This specified DHA is done on high resolution capillary column, a 1% poly(dimethylsiloxane) column. Because of its specifically important role in DHA, this column is often called PONA column. Common PONA columns are either.2mm x m x.5um or.25mm x 1m x.5um. Various software and methods have been developed for such PONA and DHA applications. There are two techniques for these applications. One is based on multi-dimensional GC, and other is based on high resolution chromatography. Both techniques use retention times of individual hydrocarbons to identify and quantify each composite separated. As the number of the composites of a gasoline can be as many as, the peak identification becomes very difficult and is very critical step for DHA. Often peak identification can be errant. Intensive labor effort is then taken to manually correct errors in peak identification. Among various softwares for ASTM D5134, the software called PONA developed by Beijing Chromtech Institute uses an algorithm of retention index to identify peaks. Because retention index is relatively insensitive to the variations from columns, instruments and methods, this software is able to automatically and correctly identify each peak with great confidence. Even though this algorithm improves accuracy of peak identification, it still requires imum variations in column dimension, column retention time, column efficiency and column selectivity. This application note describes a FCC gasoline application on an GSBP-PONA column. This GSBP-PONA column replicates the performances of HP-PONA column, an industrial fleet column, including column selectivity, column dimension and retentions. Under the same instrumentation condition, the software PONA produces the same result as the one obtained from an HP-PONA column for this application. 2. Experimental 2.1 Column: The column used is an GSBP-PONA column,.2mm x m x.5um, coated with GsBP-1 stationary phase, part number 2-PONA, obtained from GS-Tek Inc., Newark, DE 19713, USA. The column temperature limits are -C to 325/3C. Prior to each run, column was conditioned at 2C for 4hr. GS-Tek, Inc. page 1 of 7

2.2 Instrumentation conditions: Instrumentation conditions are listed in Table I. Table I the instrumentation conditions Gas Chromatography Agilent 68 GC with ALS Raw date acquisition HP-Chemstation Inlet 2C, s/s, split flow 1ml/ Carrier Nitrogen Column head pressure 99kpa varied Detector FID, C Oven 35C 1,.5C/ to C, 2C/ to 1C, 1+ Sample A FCC gasoline sample Injection 1ul 2.3 Column retention time calibration Constant pressure mode was used for carrier flow. Column head pressure was adjusted to have n-pentane retention time around 9.75+-.1 as holdup time prior to sample injection. For a comparison, the analysis was repeated on an HP-PONA column at the same instrumentation conditions. 3. Software 3.1 DHA and PONA analysis PONA software from Beijing Chromtech Institute, Beijing, China was used in a PC with OS Microsoft 95 or above. It uses the following formula (1) to calculate the retention index of all individual peaks. RIi = ((RTi-Rtref_Cn)/(Rtref_Cn+1-Rtref_Cn)+ Cn)*1 (1) RIi: Retention index of composite i RTi: Retention time of composite i Cn : Reference peak of carbon n Cn+1: Reference peak of carbon n+1 Rtref_Cn :Retention time of reference peak Cn Rtref_Cn+1:Retention time of reference peak Cn+1 GS-Tek, Inc. page 2 of 7

Retention time of reference peaks can be searched automatically based on empirical database built-in the PONA software 3.2 Calculation of Octane Number: Two octane values defined by RON and MON are calculated as RON = Cr + Fr Ai Wi (2) MON = Cm + Fm Bi Wi (3) Cr : Fr : Cm : Fm : Ai : Bi : Wi : N : given constant, RON given correlation factor, ROM given constant, MON given correlation factor, MON correlation coefficient of i th hydrocarbon, RON, listed in calibration table correlation coefficient of i th hydrocarbon, MON, listed in calibration table weight percentage of i th, measured by DHA total number of peaks measured by DHA 3.3 Calculation of Carbon/Hydrogen(C:H)ratio: C:H = (C:H)i Wi (4) (C:H)i : Carbon/Hydrogen of i th hydrocarbon Wi : weight percentage of i th, measured by DHA N : total number of peaks measured by DHA 3.4 Calculation of Specific Gravity (D): D = Di Wi (5) Di : Wi : N : Specific Gravity of i th hydrocarbon Weight percentage of i th, measured by DHA Total number of peaks measured by DHA 3.5 Data Analysis: GS-Tek, Inc. page 3 of 7

Once the separation of each composite in a gasoline sample is completed, the raw data of DHA was generated by HP Chemstation or similar data acquisition software. The raw data includes peak retention time, area and/or area percentage. The file format of the raw data file used in this PONA software is.d. After completion of the chromatography run, the PONA reads the raw data file, and automatically identify the reference peaks (as many as to 13) from assigned one of three databases for three types of gasoline. Manual correction of the reference peaks is only as needed for the first run. Once the reference peaks are correctly identified, the software can automatically calculate all physically and chemically values described in 3.1 to 3.4. The report file can be either printed or transferred for a customized report. 4. Result Fig 1 shows the comparable chromatograms of a FCC gasoline sample on GSBP-PONA and HP-PONA columns. It is clearly that the GSBP-PONA exhibits a small retention time difference from the HP-PONA column, however, the peak elution order and relative peak height ratios are essentially same. Even for this retention time difference, the PONA software is able to identify all peaks in both chromatograms. The physical properties calculated are listed in table II for the results from two PONA columns. Table II Calculated physical properties Column GSBP-PONA HP-PONA No. of peaks identified 1 Calculated RON 87.26 87.15 Calculated MON 78.18 78.7 C:H 7.33 7.34 Specific density.64.62 All other calculated values are listed in the table III. Table III PONA analysis report of a FCC gasoline sample PONA Columns GsBP HP GsBP HP Compositions Wt% Wt% V % V % P (Normal Paraffin) 3.29 3.28 3.68 3.67 I (Iso Paraffin) 25.81 25.69 28.37 28.2 O (Olefin) 9.14 9. 1.8 1. N (Naphtha) 15.74 15.72 16.2 16.19 A (Aromatic) 46.2 45.91 41.67 41.54 GS-Tek, Inc. page 4 of 7

5. Conclusion Based on the above results and same instrumentation conditions used, it can conclude that both GSBP-PONA and HP-PONA are essential identical. GSBP-PONA column has produced almost same result as HP-PONA has. 6. Order Guild Table IV lists the suggested parts for PONA application. Table IV Suggested parts for PONA analysis Item Description P/N 1 PONA software 1-PONA 2 GSBP-PONA 2-PONA 3 Gasoline Reference Sample, 1ml 3-PONA 7. Other applications of GSBP-PONA column The other applications of GSBP-PONA column would be the separations of natural gas, pesticides, and VOC. GS-Tek, Inc. page 5 of 7

.85.478.922 41.12 41.1 41.645 41.857 42.937 43.858 42.594 44.395 44.8 44.784 45.48 45.2 45.9 46.377 47.333 47.868 48.178 48.413 48. 49.372 49.735.466.846 52.191 52.628 53.46 53.62 54.317 54.611 55.14 55.514 55. 56.297 56.979 57.477 57.677 58.318 58.9 59.269 59.538 59.932 51.219 39.973.369.2.989 41.277 41.519 41.726 42.794 43.1 44.876 45.444 45.792 46.188 42.452 44.237 44.441 47.141 47.673 47.982 48.235 48.716 49.175 49.546.265.6 51.984 52.5 52.824 53.397 54.92 54.374 54.777 55.264 55.639 56.49 56.727 57.196 57.426 58.43 58.6 58.998 59.266 59.645.8 51.4 2.53 2.212 2.585 2.766 21.4 2.3 21.147 21.324 21.671 21.932 22.236 22.442 22.682 22.799 22.928 23.256 24.126 24.447 25.276 23.715 25.719 26.155 26.335 26.592 26.766 26.895 27.541 27.3 28.425 29.77 29.265 29.574 29.866 31.71 31.2 32.913 33.623 34.45 28.739.443 34.2 34.5 35.282 35.576 36.948 37.6 36.415 37.991 38.383 38.748 39.54 39.838.85 23.475 24.753 39.382 2.27 2.363 2.731 21.459 21.3 22.57 22.348 22.561 22.792 23.36 21.1 21.43 23.359 24.212 24.5 25.3 23.5 25.778 26.27 26.389 26.639 26.818 26.944 27.5 27.844 28.456 28.759 29.97 29.285 29.5 29.878 31.65 31.786 32.872 33.586 33.998.442 34.545 34.845 35.213 35.7 36.893 37.424 36.335 37.8 38.299 38.651 38.953 39.734 39.973 23.568 24.827 39.281 8.874 9.977 1.297 1.4 12.226 12.398 12. 12.989 14.711 14.634 14.275 15.575 15.668 15.937 15.826 16.75 16.287 16.533 16.5 16.824 16.963 18.141 19.99 19.8 19.523 2.53 17.576 18.697 18. 7.721 9.232 1.47 1.314 1.628 1.832 12.521 12.688 12.788 13.267 14.958 14.885 14.529 15.81 15.896 16.165 16.55 16. 16.8 16.818 17.32 17.171 18.327 17.774 18.871 19.274 19.468 19.693 18.479 FID1 A, (PONA 26-12-1 13-54-9\PONA1211.D) 2 13.394 13.516 1 2 4 6 8 1 12 14 16 18 FID1 A, (PONA 26-12-8 1-37-35\PONA1282.D) 2 1 13.114 13.243 2 4 6 8 1 12 14 16 18 FID1 A, (PONA 26-12-1 13-54-9\PONA1211.D) 32.121 32.2 2 1 2 22 24 26 28 32 34 36 38 FID1 A, (PONA 26-12-8 1-37-35\PONA1282.D) 32.152 32.296 2 1 2 22 24 26 28 32 34 36 38 FID1 A, (PONA 26-12-1 13-54-9\PONA1211.D) 2 1 42 44 46 48 52 54 56 58 FID1 A, (PONA 26-12-8 1-37-35\PONA1282.D) 2 1 42 44 46 48 52 54 56 58 GS-Tek, Inc. page 6 of 7

99.961 1.181 1.6 1.799 1.949 11.211 12.67 12.252 12.467 12.723 12.616 13.1 13.879 14.161 14.7 15.446 15.568 15.797 11.437 16.22 16.368 16.7 16.772 17.12 17.616 17.846 11.791 14.92 17.431 18.241 18.414 18.845 19.344 19.534 19.674 11.146 11.317 11.643 11.778 11.937 111. 111.571 111.8 112.212 112.411 112.545 112.814 113.241 113.3 114.65 114.21 114.578 114.8 114.994 115.239 115.596 115.831 116.173 116.541 116.967 117.523 117.764 118.32 118.438 118.659 118.997 119.6 119.915 19.172 117.337 13.542 14.555 99.9 1.164 1.615 1.9 1.967 11.213 12.65 12.2 12.459 12.636 13.1 13.891 14.177 14.317 15.4 15.813 16.232 16.382 16.641 11.426 17.38 17.654 17.859 11.781 14.929 17.4 18.256 18.428 18.856 19.367 19.574 19.4 11.185 11.352 11.661 11.795 11.978 111.136 111.626 111.5 112.245 112.437 112.589 112.856 113.289 114.1 114.257 114.613 114.737 115.27 115.316 115.657 115.876 116.235 116.582 116.811 117.16 117.5 117.812 118.364 118.519 118.696 118.6 119.48 119.357 119.719 119.975 12.134 113.8 19.1 117.372 13.533 14.5.57.229.7 81.669 81.8 82. 82.273 83.125 83.427 83.924 84.197 84.535 84.773 85.353 85.583 86.777 87.397 87.555 87.789 87.9 88.343 88.596 89.144 81.4 86.48 89.524 89.686.67.292.2 91.24 91.29 91.417 91.559 92.281 92.621 93.214 93.339 93.518 93.1 95.377 95.543 96.453 96.615 96.785 98.8 98.713 98.887 99.288 99.429 97.8 99.688 99.961 82.884 85.64 83.714.621 91.999 94.765 94.23 94.333 95.86 97.1 97.7 82.61 87.1 98.56 79.922.97.654 81.547 81.737 81.914 82.154 83.328 83.826 84.221 84.114 84.436 84.679 85.258 85.486 86.331 86.674 87.1 87.486 87.7 87. 88.256 88.535 89.76 81.1 85.962 89.444 89.628 89.9.211.7.975 91.148 91.344 91.9 92.2 92.585 93.191 93.466 93.758 95.333 95.529 95.862 96.45 96.437 96.3 96.7 97.841 98.2 98.688 98.899 99.274 99.41 99.685 99.9 82.765 84.954 83.3.545 91.927 93.979 94.2 94.722 95. 97.167 97.384 82.4 87.78 98.28 59.932.269 61.339 61.932 62.225 62.1 63.148 63.373 63.982 64.313 64.818 65.327 66.3 66.777 66.988 67.473 67.817 68.131 68.359 68.576 68.827 69.443 69.957.277.881 71.6 72.49 72.436 72.8 72.927 73.246 73.868 74.27 74.526 74.6 75. 75.2 75. 75.736 75.996 76. 76.891 77.158 77.326 77.628 77.923 78.291 79.81 79.393.57 69.744 63.699 66.56 65.833.552.8 61.73 61.662 61.952 62.336 62.897 63.126 64.57 64.569 65.57 66.114 66.5 66.743 67.252 67.5 67.91 68.139 68.583 69.225 69.743.59.653.982 71.597 71.831 72.237 72.535 72.746 73.46 73.694 74. 74.361 69.531 74.8 75.8 75.579 75.821 76.541 76.7 77.4 77.456 77.775 78.142 78.91 79.249 79.922.97 63.452 65.823 65.598.342 FID1 A, (PONA 26-12-1 13-54-9\PONA1211.D) 2 1 62 64 66 68 72 74 76 78 FID1 A, (PONA 26-12-8 1-37-35\PONA1282.D) 2 1 62 64 66 68 72 74 76 78 FID1 A, (PONA 26-12-1 13-54-9\PONA1211.D) 2 1 82 84 86 88 92 94 96 98 FID1 A, (PONA 26-12-8 1-37-35\PONA1282.D) 2 95.888 96.81 1 82 84 86 88 92 94 96 98 FID1 A, (PONA 26-12-1 13-54-9\PONA1211.D) 2 1 1 12 14 16 18 11 112 114 116 118 FID1 A, (PONA 26-12-8 1-37-35\PONA1282.D) 2 113.642 113.2 1 1 12 14 16 18 11 112 114 116 118 Fig. 1, Chromatograms of a FCC gasoline sample on an GSBP-PONA column and an HP-PONA column. Top, GSBP-PONA; bottom, HP-PONA. Instrumentation condition is shown in Table I. GS-Tek, Inc. page 7 of 7