1、GPA TP-20 7b 3824679 0017873 T58 Technical Publication TP-20 Effect of Ammonia on LP-Gas Odorant J. W. Goetzinger D. L. Ripley National Institute for Petroleum Energy Research Bartlesville, Oklahoma May, 1996 6526 East 60th Street . Tulsa, Oklahoma 74145 . Phone: 91 8/493-3872 . Fax: 9181493-3875 GP
2、A TP-20 7b m 3824b99 0017874 994 m DISCLAIMER GPA publications necessarily address problems of a general nature and may be used by anyone desiring to do so. Every effort has been made by GPA to assure accuracy and reliability of the information contained in its publications. With respect to particul
3、ar circumstances, local, state, and federal laws and regulations should be reviewed. It is not the intent of GPA to assume the duties of employers, manufacturers, or suppliers to warn and properly train employees, or others exposed, concerning health and safety risks or precautions. GPA makes no rep
4、resentation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may conflict, or for any in
5、fringement of letters of patent regarding apparatus, equipment, or method so covered. GPA TP-20 96 m 3824699 0037875 820 m NIPERIBDM-O220 FINAL REPORT EFFECT OF AMMONIA ON LP-GAS ODORANT RESEARCH REPORT BY J.W. Goetzinger and D. L. Ripley Work Performed Under Contract No. DE-AC22-94PC91008 Prepared
6、for US. Department of Energy Bartlesville Project Office DISCLAIMER his report was prepared an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or
7、 assumes any legal liability ar responsibility for the accuracy, completeness, or usefuiness of any infomiation, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commeraai product, process, or service by
8、trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necgsarily state or reflect those of the United Sta
9、tes Government or any agency thereof. BDM-OKLAHOMA, INC. PO Box 2565 Bartlesville, Oklahoma 74005 GPA TP-20 96 3824679 00L787b 7b7 TABLE OF CONTENTS SUmrnary 1 Background 1 Objective 1 Introduction 2 Recul . 2 Conclusions 3 Appendix . 11 TABLES Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Figure
10、1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Ethyl Mercaptan Gas Chromatograph Peak Areas . 4 Ethyl Mercaptan Concentrations. pprn . 5 Ammonia Concentrations in Propane. ppm 6 Hydrocarbon composition of commercial propane . 15 Initial determination of ethyl mercaptan in test tanks 15 Init
11、ial ammonia concentrations in propane blends . 17 FIGURES Change in Ethyl Mercaptan Peak Area with Time; Propane plus 4 ppm Ammonia in Tank 1-12 7 Change in Ethyl Mercaptan Peak Area with Time; Propane plus 3 pprn Ammonia in Tank 1-3 7 Change in Ethyl Mercaptan Peak Area with Time; Change in Ethyl M
12、ercaptan Peak Area with Time; Change in Ethyl Mercaptan Peak Area with Time; Change in Ethyl Mercaptan Peak Area with Time; Propane plus 70 ppm Ammonia in Tank 2-2 9 Change in Ethyl Mercaptan Peak Area with Time; Propane plus 12 ppm Ammonia in Tank 14 8 Propane plus 12 ppm Ammonia in Tank 1-5 8 Prop
13、ane plus 50 ppm Ammonia in Tank 1-10 9 Propane with no Ammonia, in Tank 1-11 10 11 GPA TP-20 96 3824679 0037877 bT3 FINAL REPORT EFFECT OF AMMONIA ON LP-GAS ODORANT by John W. Goetzinger and Dennis L. Ripley SUMMARY This project was designed to examine the effect, if any, of ammonia contamination ai
14、 the ethyl mercaptan odorant in commercial LP-Gas. Standard 20-pomd propane tanks were filled with commercial odorized propane, and the ethyl mercaptan concentration in each was determined by gas chromatography. After the ethyl mercaptan concentration trends had been established, ammonia was added t
15、o the tanks in concentrations ranging from 3 - 78 ppm, comparable to the concentration of ethyl mercaptan. Liquid propane from each of the tanks was analyzed periodically for both ethyl mercaptan and ammonia for about 6 weeks, to detect any changes in the concentrations resulting from a reaction. No
16、 change in ethyl mercaptan concentration attributable to the addition of ammonia could be detected. Therefore, it was concluded that there was M reaction between ammonia and ethyl mercaptan, and that contamination of propane with low concentrations of ammonia would have m effect on the concentration
17、 of ethyl mercaptan odorant., BACKGROUND Although ammonia is not a naturally occurring contaminant of LP-Gas, certain industry practices, including dual use of transportation or storage equipment, may inadvertently result in contamination of LP-Gas by ammonia. For example, tank trucks used for trans
18、porting LP-Gas in the winter are also frequently used to transport liquid ammon,ia during the summer months. Regulations require that tanks that have been used for storing or transporting ammonia must be adequately cleaned before they are used for LP-Gas; however, there is a possibility that inadequ
19、ate cleaning could leave traces of ammonia in the tank, which would then contaminate the LP-Gas. Although such contamination is not considered likely to happen, this project was directed to determining if ammonia will react with ethyl mercaptan odorant in LP-Gas, reducing the odorant concentration.
20、OBJECTIVE The objective of this project was to determine the effect of ammonia contamination ai the concentration of ethyl mercaptan odorant in LP-Gas. 1 INTRODUCTION Seven standard 20-pound propane tanks were filled with commercial odorized propane and allowed to equilibrate. The initial concentrat
21、ion of ethyl mercaptan odorant in the liquid propane was determined by gas chromatography shortly after the tanks were filled, and the odorant concentration was then measured periodically over a period of 12 days to determine the stability or rate of decline of the odorant concentration. After the d
22、ecline rate of the ethyl mercaptan concentration had been established, a small quantity of ammonia was added to six of the tanks. The target concentrations of ammonia to be added were 5/25, and 50 ppm, with duplicates of each concentration. These target ammonia concentrations range from less than th
23、e normal concentration of ethyl mercaptan to greater than the typical ethyl mercaptan concentration. Analysis of the propane with Gastec detector tubes after addition of ammonia showed that the actual ammonia concentrations were about 3 to 4 pprn in two tanks, 12 ppm in two tanks, 50 ppm in one tank
24、, and 70 ppm in one tank. The seventh tank was left without ammonia as a reference control. Following the addition of ammonia, the concentrations of both ethyl mercaptan and ammonia in the liquid propane in each tank were determined periodically over a period of about 6 weeks to detect any change in
25、 the respective concentrations that would indicate a reaction between ethyl mercaptan and ammonia. The ethyl mercaptan determinations were accomplished by gas chromatography, using a packed Chromosil 330 column and an electrolytic conductivity detector. The ammonia concentrations were determined wit
26、h Sensidyne Gastec gas detector tubes. Details of the experimental procedures are contained in Appendix 1. RESULTS After ammonia was added to the propane, the liquid propane in each tank was analyzed for both ammonia and ethyl mercaptan at frequent intervals in order to determine any significant cha
27、nge in their concentrations, which would signal a possible reaction between the ammonia and ethyl mercaptan. The analyses were performed each day for the first 3 days, then every few days, and after 2 weeks about once a week, over a total time period of about 6 weeks after the ammonia was added, or
28、over 7 weeks after the tanks were first filled with propane. A sample of liquid propane was taken from each of the seven tanks, allowed to evaporate, and analyzed at each time period. Each sample of vaporized liquid propane, contained in a Tedlar bag, was analyzed first for ammonia, using a single G
29、astec detector tube, then for ethyl mercaptan by gas chromatography. Several GC determinations were made ai each sample and the individual results averaged to give the ethyl mercaptan peak area for each sample. The ethyl mercaptan peak areas for the propane samples from all seven tanks, both before
30、and after addition of ammonia, are summarized in Table 1. Table 2 shows the same results converted to pprn concentration of ethyl mercaptan. The ppm values were computed from the sample peak areas compared to the average peak area of the 50 ppm calibration blend. 2 The data are also shown graphicall
31、y in Figures 1 through 7, in which the ethyl mercaptan peak areas are plotted against the time the propane was in each test tank. The measured concentration of ethyl mercaptan in propane samples from each tank varied somewhat from day to day, due to inherent variability of the GC procedure and respo
32、nse of the electrolytic conductivity detector, but there was a small general downward trend in ethyl mercaptan concentration in all the tanks. Although the decline rate was faster in some tanks than in others, in each tank it appeared to be the same both before and after ammonia was added. Tank 1-11
33、, which did not have any ammonia added, exhibited the greatest decline in ethyl mercaptan concentration. In all the tanks, there appeared to be a drop in ethyl mercaptan concentration at the time the ammonia was added, with the concentration subsequently increasing again. The magnitude of the concen
34、tration drop did not appear to be related to the quantity of ammonia added, and it was also apparent in propane from the tank to which m ammonia had bem added. Therefore, it was concluded that the apparent drop in ethyl mercaptan concentration was simply an artifact of the analysis, caused by variab
35、ility in the gas chromatograph and detector. All tanks exhibited very similar levels of ethyl mercaptan concentration throughout the entire test period, with m indication of any reaction of the ethyl mercaptan with ammonia. In fact, as mentioned previously, the greatest change in the ethyl mercaptan
36、 concentration occurred in the tank with no ammonia. he ammonia concentrations, as determined by Gastec detector tubes, are shown in Table 3. At the low and intermediate concentrations, there appeared to be a slow decline in the ammonia concentration over the course of the study, while in the two hi
37、gh ammonia concentration blends the ammonia concentration remained constant within the reproducibility of the detector tubes. CONCLUSIONS Three different concentrations of ammonia were added to commercial odorized propane from a local supplier to determine if there was any reaction between the ammon
38、ia and the ethyl mercaptan odorant in the propane. The addition of ammonia to the propane had m detectable impact an the ethyl mercaptan concentration, although the ethyl mercaptan concentration in all the test tanks decreased slowly with time. The decrease in ethyl mercaptan concentration was actua
39、lly greater in the tank that contained no ammonia than in any of the tanks to which ammonia had been added. Based on our experimental results, we concluded that there is m reaction between low concentrations of ammonia, which might occur if a tank were contaminated with traces of ammonia, and the et
40、hyl mercaptan odorant in commercial propane. These experimental results indicate that ammonia does not have any effect on the ethyl mercaptan odorant, and does not reduce the concentration of the odorant. 3 Table 1 Ethyl Mercaptan Gas Chromatograph Peak Areas Days Days after after Propane Ammonia Da
41、te Fill Added Tank 1-12 Tank 1-3 Tank 1-4 Tank 1-5 Tank 1-10 Tank 2-2 Tank 1-11 Nov. 15 Nov. 16 Nov. 17 Nov. 20 Nov. 27 Nov. 28 Nov. 29 Nov. 30 Dec. 1 Dec. 4 Dec. 8 Dec. 13 Dec. 20 Dec. 29 O 1 2 5 12 13 14 15 16 19 23 28 35 44 1 2 3 6 10 15 22 31 337,133 31 8,269 31 3,477 301,152 3.5 295,354 279,466
42、 299,459 290,924 288,318 264,734 267,981 269,437 364,650 347,241 353,988 357,198 350,304 346,162 349,854 344,145 342,586 331,330 334,985 325,419 339,798 325,726 344,522 328,775 AMMONIA ADDED, ppm 2.6 12 12 50 316,499 312,753 314,673 297,856 302,660 31 8,073 298,469 283,991 302,682 323,581 322,940 31
43、 1,857 306,870 296,530 31 1,248 296,544 314,383 306,968 31 8,053 295,698 302,085 291,129 306,049 282,345 292,772 297,636 278,575 286,800 298,206 303,695 314,958 285,384 373,925 352,422 339,658 320,902 336,018 303,512 350,435 299,430 NO 78 AMMONIA 315,622 262,570 321,031 274,789 327,128 285,309 329,0
44、84 266,554 337,630 272,116 31 9,599 246,319 320,855 234,199 334,125 256,012 Jan. 5 51 38 276,751 304,845 308,834 31 5,749 287,833 332,517 249,396 4 GPA TP-20 76 3824677 OOL788L 024 = Table 2 Ethyl Mercaptan Concentrations, ppm Days Days after after Propane Ammonia Date Fill Added Tank 1-12 Tank 1-3
45、Tank 1-4 Tank 1-5 Tank 1-10 Tank 2-2 Tank 1-11 Nov. 15 O Nov. 16 1 51.6 49.1 50.1 50.5 47.7 52.9 49.9 NOV. 17 2 45.0 49.6 49.0 49.5 48.7 48.1 45.4 Nov.20 5 44.4 48.5 46.9 47.4 46.1 47.6 43.0 Nov.27 12 42.6 48.1 46.1 48.8 46.5 49.6 42.4 Nov. 28 13 AMMONIA ADDED, ppm NO 78 AMMONIA 3.5 2.6 12 12 50 Nov
46、.29 14 1 41 .8 44.8 44.3 44.5 42.1 44.7 37.2 Nov.30 15 2 39.5 42.8 45.0 42.2 40.2 45.4 38.9 Dec. 1 16 3 42.4 42.8 45.8 45.7 44.1 46.3 40.4 Dec. 4 19 6 41.2 43.4 42.0 44.0 42.0 46.6 37.7 Dec. 8 23 10 40.8 44.5 43.4 45.0 41.8 47.8 38.5 Dec. 13 28 15 37.5 42.7 41.2 43.3 40.0 45.2 34.9 Dec. 20 35 22 37.
47、9 41.2 42.1 39.4 40.6 45.4 33.1 Dec. 29 44 31 38.1 42.2 43.0 44.6 40.4 47.3 36.2 Jan. 5 51 38 39.2 43.1 43.7 44.7 40.7 47.1 35.3 5 Table 3 Ammonia Concentrations in Propane, ppm Days after Ammonia Date Added Tank 1-12 Tank 1-3 Tank 1-4 Tank 1-5 Tank 1-10 Tank 2-2 Nov. 29 1 3.5 2.6 12 12 50 78 Nov. 3
48、0 2 2.8 2.8 10 10.5 45 68 Dec. 1 3 3 2.5 9 11 45 78 Dec. 4 6 2.5 1.8 10 10.5 50 80 Dec. 8 10 2.5 2.2 9 12.2 48 80 Dec. 13 15 1.3 4 9.7 10.5 45 80 Dec. 20 22 3 1.8 9 10.5 50 85 Dec. 29 31 2.4 2.4 8.5 9.5 50 80 Jan. 5 38 2.2 1.8 8 10.5 48 85 6 400,000 350,000 300,000 250,000 (A a Y 200,000 n 150,000 1
49、00,000 50,000 O GPA TP-20 96 m 3824b99 OOL73 9T7 m “3Added O 10 20 30 40 50 60 Days after filling with propane Figure 1 Change in Ethyl Mercaptan Peak Area with Time; Propane plus 4 ppm Ammonia in Tank 1-12 400,000 350,000 300,000 - I I - I (A 250,000 i “3 Added d I Y 200,000 n 150,000 f 100,000 50,000 o1 I I 1 I I 1 l I O 10 20 30 40 50 60 Days after filling with propane Figure 2 Change in Ethyl Mercaptan Peak Area with Time; Propane plus 3 ppm Ammonia in Tank 1-3 7 GPA TP-20 9b = 3824699 0037884 833 350,000 300,000 T 400,000 I- I I I - - - 250,000 “3 Added CR 4 250,000 200
