Document zqenDNkJgLjgzqNqrgwjmbdz

. 4 Chemical Research Laboratory im_lgPECT OF RERUNNING ON THE TEL AMP BROMINE CONTENT OP AVIATION GASOLINE PURPOSE To determine the lead and bromine content of the overhead and bottom cuts from the distillation, made by the Socony-Vacuum Company of a large batch of contaminated aviation gasoline. SUMMARY Some 633#000 gal. of finished 100-octane gasoline, nominally containing 4.6 cc. TEL (tetraethyllead) and 3.75 g. bromine per gallon, and having a high gum content, was rerun at below 300C, taking 96$ overhead in two cuts. The analyses summarized in Table I below show that 26# of the TEL and 95# of the ethylene dibromide was distilled over, and also that the distillation was modified at some stage to give a different proportion of overhead product. A small amount of TEL apparently was .lost by decomposition, but 65# of it remained in the 26,000 gal. of bottoms,'which thus contained 71 cc. TEL/gal. The overhead material, with its high bromine-lead ratio, is to be blended with 9 volumes of fresh aviation stock. If Aviation Fluid is then added to make 4.6 cc. TEL/gal., this will give I .0 7 theory of bromine in the finished blend, an acceptable amount. * The high TEL content of the bottoms calls for caution in handling, in accordance with the recommendations which have been made by the Safety Department. This has been done by washing out the still with 300,000 gal. of unleaded base stock, reducing the TEL content to 5.60 cc. gal. . This material is to be'further diluted some 12-fold, and TEL added as needed,to make motor gasoline. One sample of such . unfinishedmaterialsoontaied,.l.i4;du> TEL/gal. of which some 40# was lead from the rerun operation." 'This sample was accordingly low in . halogen content/ containing only 60# of the requisite amount. In view of the possible detrimental effect of this* it would seem advisable to add the addition halogen compounds required to make up the'deficiency. INTRODUCTION -. * On March 31, our safety engineer, Mr. M. I. McCooley re ported to R . L . G o l t z that: "The Socony Vacuum refinery at Paulsboro, N. J., was asked by the Government to recondition two tanks of avia tion gasoline 1 0 0 octane, containing 4.6 cc. of TEL, that had been K ET GOO5306 rv / . 2. gasoline contained 30 milligrams of gum and the other contained 68 milligrams of gum, and were turned down as they were above the 6 milli gram specification. "They received 632,940 gallons and recovered overhead 606,394 gallons, by running it through a refined oil still at 40 pounds low pressure steam, and not over 300 degrees temperature. balance of 25300 gallons were considered bottoms in the still. The "They put this reconditioned gasoline into two tanks at their refinery. Tank 562 representing 58# of the recovered gasoline contained 0.70 cc. per gallon of TEL, tank 563 representing 42$ ov recovered contained 2.0 cc. and the bottoms in the still contained 71.0 cc." It was planned to reblend with new stock in the proportions of 9*1 for the overhead and 400:1 for the bottoms, adding the bottoms to house brand gasoline. For safety in handling the bottoms, the still containing that material was to be considered as a blending tank. On April 28, Mr. McCooley reported further that "about 8,000 hbl." of unleaded base stock was circulated through the still into a storage tank? the product, containing "7.6 cc." of TEL per gallon, is used to furnish 25$ of the lead requirement in a blend of house brand gasoline. At our request, samples of the two overhead cuts, the bottoms before and after dilution, and the finished motor gasoline were sub mitted to this Laboratory and It was decided to determine the distri bution of bromine and to confirm the Socany-Vacuum figures for TEL content. . ANALYSIS Samples from Rerunning Operation The three samples, our No, M-546, were analyzed as received, being free from sludge: presumably the bottoms sample had been fil tered. The overhead cuts had a faint blue color, the bottoms a deep blue. Bromine analyses were made by the sodium biphenyl method (see forthcoming LTD) which should give better than 98$ recover. The re sults for TEL and bromine are given in Table I. K Z 00C5307 TABLE I - ANALYSES OP RERUN MATERIAL 3 0 Recovery calculated for Input of 4.6 ec. TEL/gal. In Aviation Fluid Overhead Volatility.P TEL Bromine Vol,.0 log M M M * 22S_ cc./gal. 0 Ree. B jJ b I x % Reo Overhead Tank 562 Tank 563 Total Bottoms ' Loss or error 55.5 40.3 95.8 4.2* I3O 144 282 260 0.80 3.4 273 1.86 4.2 1.25 26.0 3.7 95 341 70.9 64.7 3.3 3.8 9.3 1.4 *3y difference. There were no ammonia-soluble bromine or lead salts in any of the samples, except for a trace of lead in the bottoms sample, 0.5 g. Pb/gal., showing that decomposition products such as triethyllead bromide were absent. Distillation data are given in Table II. From these as well as the TEL values It is evident that the course of the distilla tion was changed at some stage in the direction of a higher propor tion taken overhead into Tank 563 TABLE II - DISTILLATION DATA Sample 3p. gr. Distillation Initial 100 500 900 Pinal Recovery Residue Loss Tank 562 0.7143 97 130 196 260 310 98.1 0.6 1.3 Tank 563 O.73O9 102 144 222 273 311 98.2 0.7 1.1 Bott 0.82' 26O 282 ' 301 341 394 98 .O 1.5 0.5 CO Diluted Still Bottoms and Finished Gasoline o CP LO The two samples, our No. M-562, were only analysed for C.J) TEL and halogen, with the results given in Table III. O o TABLE III - ANALYSES OP PILOTED SAMPLES Ul TEL Bromine Chlorine______ oc./gal, g./gal. theories g./.gax^ theories Diluted bottoms 5.60 0 .2 0 0.04 0.24 0.57 V DISCTJSSIOrT 4. Rerunning Operation In calculating the percentage recovery of the TEL and bromine, it was noted that the volumes of rerun material cited above do not balance by over 1000 gal., and that the relative proportions of the two overhead cuts are probably only approximate. Moreover, the dis crepancies between the TEL analysis from Sooony-Vacuum and from this Laboratory suggest that these cuts were not homogeneous. Also, the exact amount of Fluid in the original is' not given. As a result, the calculated recoveries given above in Table I are somewhat approxi mate. With this in mind, and in view of the absence of ammoniasoluble bromine salts, it is probable that the recovery of ethylene dibromide was essentially complete. On the other hand, the 9# loss of TSL appears greater than can very well be accounted for by errors in the analysis or the material balance, and decomposition to this extent is not unreasonable in view of the necessarily high tempera ture and time of heating required for the distillation. That the distillation operation was changed as the run proceeded is perfectly evident from the volatility data in Table II, as well as from the lead analyses, although Mr. McCooley was informed that no changes were made. The amount of reflux must have been very small, judging from the percentage of TSL distilled over which is ju3t about that calculated for simple distillation of aviation gaso line. Hence, a very slight change in the reflux could have accounted for the difference between the two overhead cuts. The distribution of the ethylene dibromide is unexpected, in that its concentration in the bottoms sample, 3 .3 g./gal., is nearly as high as in the original, although its boiling point (268F) is distinctly lower than the average boiling point of the bottoms. However, that result Is confirmed by the analysis of the diluted bottoms, which gave 0.20 g./gal. compared with 0 ,26 g./gal. calculated from the above value. Reblending Operations Overhead cuts. - In reblending with 9 parts of new product, it is presumed that addition Aviation Fluid will be added to make up the deficiency in TEL and give 4.6 co. in the finished blend. This will give a small excess of bromine, 0 .0 7 theory on the average, which is allowable. Dilution of still bottoms. The quoted TEL content of 7.6 cc./gal. is presumably a typographical error, and the analytical K 0 0 05309