Патент USA US2118771код для вставки
. tented ay '24, i938 UNITED STATES PAEN _ :.2,il18,77l "j'QFP-l' ' , _ SOLVENT TREATMENT or‘ NAPn'rnAs THE LIKE - -, , Ernest Tel-res, New York, and Erich -Saegebarth, _ - Long Island City, N. Y., and Joseph Moos, "Ber- ' , ' ‘ lin-Mariendo'rf, Germany, assignors, by mesn'e = assignments, to Edeleanu Gesellscliaft, m. b. 11., * Berlin, Germany, a corporation of Germany No Drawing. Application May 15,, 11935, ' Serial No. 21,680 2 Claims. (oi. l96-37) , _ _ This ihvention relates to,'impi'bvements in ‘stantially below 'zero degrees Fahrenheit, and the Edele'anu process for producing motor that, _if'the extraction temperature is chosen fuels, especially gasolines, of ‘a high anti-knock su?iciently low, the liquid sulphur dioxide splits - value, described in United States Patents .‘No.' the gasoline fraction into a ra?inate being ‘prac 5 1,585,473,1dated May 18, 1926,.and No. 1,661,566, tically free of unsaturated hydrocarbons and an 5. - dated March 6, 1928, and also tothe production’ extract containing practically only unsaturated of improved lacquer solvents. _ ~ and aromatic hydrocarbons. v This split will be These patents describe processes of re?ning gasolines and kerosenes by splitting the crude 0 distillate into a lower boiling and a higher boiling sharper and the more complete the lower the tem perature of \extraction, and there is no technical but only an economical limit to reducing the 10 fraction, treating the latter with liquid sulphur extraction temperatura,, ‘ dioxide and reblending the extract obtained by Two factors are of chief importance for ?xing such treatment with the non-treated lighter‘ the ‘temperature of treatment with liquid sul fraction. This extract has a considerably higher phur dioxide, the one being the boiling range of content of aromatic andnnsaturated hydrocar bons than the original stock and, since the pres ence of these constituents in the motor fuel-is chie?y responsible for its anti-knock quality,’ it is apparent that by adding the extract obtained 0 from the higher'iboiling fraction to the lower boiling one the anti-knock value of the latter is increased. ' The anti-knock quality of a motor fuel is ex pressed by its “octane number”, the antié-knock 5 value being higher the higher the octane num ber. By eniploying the processes described in the above cited patents it has been possible to the gasoline out to be re?ried and the other its _15 original content of" aromatic and unsaturated hydrocarbons. The lower the boiling range of the gasoline fraction is and the‘ higher its con tent of aromatic and unsaturated components the more advisablevwill it be to employ a'very 20' low temperature in extracting. Temperatures as low'as -60 to -'70° F. are ‘still allowable for technical reasons as well as'from an ‘economical viewpoint. . - _ ' , v I - ' . According to our invention the following. dlf-. 35 ferent steps may be employedfor producing an extract of the speci?cation given above: _ ' produce gasolines havingoctanenumbers of. 70 - (w) The naphtha fraction is treated with liquid to '75. Sulphur dioxide treatment of the higher ' sulphur dioxide? at the conventional temperature 0 boiling fraction oi’ a gasoline. as described in of +14 to +20“ F. in an extractiontower of con- '30 said patents, has been customarily done at tem ventional. type. The extract layer obtained peratures between +14° F. and +20° F., the ex thereby by settling is further cooled down to tract obtained in this manner having an average ' _ about —60° to' -70° F., whereby this extract layer concentration of aromatic and unsaturated con 5 stituents of 351to 40 percent. a New developments in the'design of internal combustion engines, especially for aeroplanes. make it desirable to re?ne the gasoline to such an extent that the octane number is raised above c the limit of 75 mentioned above. ' _ ' We have found that such ?rst grade gasolines is again split in two phasespan upper ra?lnate layer that has practically the samecharacter- 35 istics as the ra?inate obtained in the ?rst ex traction step, and a new extract layer. which we may call second extract .and which contains in ' some inst tnces more than twice as much aromatic _ and unsaturated components as the extract ob- 40 tained in the ?rst step of extraction. (b) Re?ning of the naphtha fraction is done cut of the gasoline crude to ‘such a degree that‘ ‘in one single step, whereby the naphtha is cooled the extracts from this re?ning step have a very down to -60 to -—70° F. and continuously intro‘ 5 high content of aromatic and unsaturated hy drocarbons and are largely free of saturated hy-' duced into the base of a conventional extraction 45 drocarbons. By blending such extracts with the tower while liquid sulphur dioxide of substan untreated gasoline fraction of lower boiling tially higher temperature, for instance it to 20° range, a gasoline is obtained, the octane number F., is charged vto the upper part of the tower. 3 of whichmay be as high as 85 and above. With In continuous operation a temperature gradient 50 the methods employed for re?ning motor fuel so will result from this method, the temperature of the liquid gradually decreasing from'the top to far, it has not been possible tocommercially pro ‘duce such a gasoline. 4 . the‘base of the extraction tower. The extract For producing extracts of the speci?cation given withdrawn from the base of the tower'will be su 5‘ above it is necessary to employ a solvent of ex perior to that obtained in the ?rst step ‘oi’ the as may be produced by re?ning the higher boiling cellent-selectivity. Unfortunately any solvent is only slightly selective on low boiling petroleum fractions such as gasoline. However, we have found that liquid sulphur dioxide exerts a very 1 high selective solvent action at temperatures sub method desbribed under (a), (c) Re?ning of the naphtha fraction is done in a single step as described under (b), but’ both stock and .liquid sulphur dioxide are charged to the extraction tower with ‘a temperature of -60 to 2 2,118,771 to -70° F. The extract obtained in this way will results may be seen in detail from the following have a concentration of unsaturated and aro table: . matic hydrocarbons equal to or ‘even surpassing that of the extract produced by method- (a), but requires somewhat more refrigeration. In each of the three methods described above a series of mixers and settlers combined to make a unit that is conventionally called multi-stage mixing-settling equipment may be used in 'lieu 10 of the vertical single extraction tower. It is fur ther understood that the process described herein is not restricted to operation upon gasoline fuel nor to the temperatures speci?ed above. Both straight run and cracked naphtha can be 15 treated in accordance with our invention to pro duce superior motor fuels; therefrom. ' As illustrations of the improvement, which may be obtained in treating light oils at temperatures substantially below zero degrees Fahrenheit, we 20 mention the following examples: Original cracked nap h‘ th a ~ Extract at —22° Radi nate at Extract F. —60° F. F. Yield percent by ~ vol ............. __ 100 19 81 °A.P.I-.' ________ __ 46.4 59.0 43.1 ' " 40 60 58.3 Percent aromatic and unsaturated hydrocarbons . -_. 50 6 61 0 80 Sayholt color _____ __ +23 +25 Dark. +25 Dark. The two fractions of the original naphtha from which the higher boiling one had been extracted with the result mentioned above had the follow ing speci?cations: - Lower boiling fraction Boiling range ____________________ __ 100-180" F. 0 Amount______..___.__ 93 vol. % of original stock ' Higher boiling fraction Example 1 Boiling range ____________________ __ PTO-250° F. A naphtha cut with 57.9° A. P. I. gravity and 25 a. boiling range from 152 to 252° F. was treated in the countercurrent manner with 65% liquid— S02 at +14° F. in one case and with 60% liquid $02 at —22° F. in another case. The yields of ra?inate and extracts and their speci?cations are 3.0 shown in comparison with the original naphtha in the following table: I Amount ______ __‘______ 7 vol. % of original stock IS G1 The octane number of the untreated lower boil ing fraction was '78. ' The yield of extract from the higher boiling fraction was 60%, and this extract contained 80% aromatic and unsaturatedcompounds. The a: 0 extract was reblended with the whole untreated lower boiling fraction with the result that the octane number was raised to 84. Extract The extraction of naphtha fractions at such naphtha +14“ F. +14‘7 F. —22° F. —22° F. low temperatures as mentioned above can be - . Raili- Ongmal mite at 35 Extract at Ra?i- nate at at 40 vol _____________ __ 100 62 38 80 20 ° A. P. I ......... .1 Percent aromatic 57. 9 63. 0 49. 4 63. 0 -' 40. 1 16 +17 2. l +23 38. 4 +10 2.0 +23 65.0 +4 and unsaturated hydrocarbons. _.. Saybolt color _____ -_ avoided when using an auxiliary solvent, which increases the selectivity of liquid sulphur dioxide. Yield percent by In this case extraction temperatures as low as 14° F. are sui?cient to obtain extracts with higher 'contents of aromatic and unsaturated com pounds. I Example 3 The naphtha fraction used in this example had the following boiling range: 45 The content of aromatic and unsaturated hydro I. B. P. 10 20 30 40 50 60 "I0 80 90 carbons was determined by means of sulphuric acid of 100% strength. A comparison of the ?gures shows that the ra?inate yield is increased from 62% to 80% by 50 carrying out the extraction at —22° F. instead of at +14° F., and that the concentration of the arc matic and unsaturated components in the ex tract was raised from 38.4% to 65%. 55 End pt. 304 Example 2 ' A cracked naphtha with a 46.4“ A. P. I., boiling range from 195 to 286° F. and containing as much as 50% aromatic and unsaturated hydro '60 carbons could not be extracted at all with liquid S02 at +14° F. because of entire miscibility at this temperature. However, by reducing the tem perature to —22° F. a separation into ra?inate and extract phase took place and the treatment 65 could be carried out in the normal way. For The A. P. I. gravity of this untreated fraction was 49.0. This naphtha fraction was extracted with sul phur dioxide and several mixtures of the latter with an auxiliary solvent, such as ethylene glycol, diethylene glycol and‘ trimethylene glycol.‘ All extractions were carried out at 14° F. and the ex tracts showed the following specifications: Extraction Extraction Extraction with sul with sul~ with sul Extrac diox phur diox phur diox tion with phur ide plus ide plus ide plus sulphur ethylene diethylene trimethyl dioxide one glycol glycol glycol 20:80 20:80 20:80 comparison the cracked naphtha was treated with 100% S02 followed by two treatments with 50% S0: at —22° F. and in another case the same stock was similarly treatedat —60° F. The lat ter treatment resulted in a greatly improved ra?lnate yield and in a higher concentration of aromatic and unsaturated components in the ex tract, indicating the advantage of extremely low 75 treating temperatures in some instances. 220 229 232 236 240 244 249 255 263 276 The “A. P. I __________ __ 39. 1 38. 4 38. 7 Percent aromatic unsaturated hy drocarbons _____ -. 48 68.7 10. 7 60. 3 Saybolt color .... __ +9 0 '10 Dark 75 aria-771. ‘Other extractions were carried out with a simi ~ mal extractions inasmuch as .they have alhigher lar vfavorable effect with mixtures of sulphur di solubility for lacquer because of the higher per oxide and the following auxiliary solvents: ben-' centage of aromatic and unsaturated components ' zy'lalcohol and diacetone alcohol. The separation present. One of the great advantages of naphtha ‘ of these auxiliary solvents from the railinates and extracts over other lacquer solvents consists in _ extracts was effected with the ?rst one by means that their boiling range increases gradually and ' of distillation and with the second one by means of washing out the solvent with water. evenly without showing breaks in the distilla= tion curve. Consequently the formation of streaks, after applying the lacquer solution, is eliminated. The extraction may be carried out 10 } As auxiliary solvents suitable for use in ac 10 cordance with this invention, there can be used any solvent miscible with liquid sulphur dioxide andselective against saturated low boiling h-y drocarbons, which has a suitable boiling point in the same manners as speci?ed above in refer ence to motor fuels under (a), (b) and (c). _ A substantial improvement in results and sav in comparison with the naphtha. fraction or ing may be obtained by following the steps of 115 which can be washed out of the ra?inates and Methods ((1) and.(b), above described, as com i5. the extracts by means of other solvents easy to' pared with treating the entire volume of naphtha separate from the naphtha hydrocarbons. Naphtha extracts produced by means of liquid at low temperatures. Thefollowing examples are illustrative. ~ sulphur dioxide at the normally employed ex 20 traction temperatures of +14 to +20 degrees _ Fahrenheit have also been usedlas lacquer sol vents. The kauri gum number is an indication of the amount of naphthenic constituents present in a lacquer solvent, and a good solvent should 25 have a kauri gum number of not less than 70. Example 5 (a) A naphtha sample was treated at 0° F. 20 with 70% by volume S02. The extract solution, instead of charging it directly to the solvent re covery still, was ?rst cooled to -60° F. which resulted in the separation of an intermediate oil. The three products, ra?‘inate, ‘intermediate oil 25 and extract, were freed from S02 and analyzed, the results being as shown in the table below. Example 4 A naphtha from Gulf Coast crude was treated 30 with sulphur dioxide at temperatures between -40° F. and +14“ F. I Four treatments with ' (b) The same naphtha was extracted counter currently at a temperature decreasing from 0° F. to —-60° F. ,with 70% by volume S02, the condi— 30 3?.5% of S02 by volume were given at each tefn~ tions being such that the S02.was admitted at perature, and the kauri gum number of the ex the top of the extraction tower at a temperature . tract determined. 35 Treatment with so, I. 2 3 . 4 Original ‘ in batch volume, (untreated) percent ’ 4X37.5 4X37.5 Temperature, °F_.__ Extract yield, vol .ume percent ____ __ Kauri gum Now.. It can-be seen from the table that a satisfac of 0° F. and the naphtha stock at the bottom at a temperature of .,—60° F. By, suitable cooling arrangements the temperature at the top of the 35 extraction tower was held at 0° F., in the middle of the tower at _v—v30° F. and at the'bottom at —60° F. The results are shown in the table below. (0) For purposes of comparison, the same stock was treated under the same conditions as-infv M (b) excepting that a temperature of --60° F. was ‘maintained in the whole tower. The results of table: these treatments are shown ' in the folio Treatment v01) (0) (0) 509' Or! (5%“ a! 70 vol. percent 8011 at ' 0° F. extract cooled to 70 Vol‘ m'ggg —B0° I‘. to reject inter- 40o n; ,mediato oil 5% Ref. Yield _____________________ -_ . to ?nes > Kauri gum No ___________ __ Octane No. Q. r. n ....... __ 100 46.8 ' - 1316' Extr. 53.5 13.6 - 53.1v sec sac 34.0 29.8 2.0 9.5 sec 46.1 51.9 32.7 Below 41 38.3 46.2 81.9 01.1 Ref. Extr. 66.0 54.0 ' . . 34.0 33.6 ml. in. sec 53.0 0.5 84.0 - 0m 32.4 Below 41 82.4 90.6 82.5 Below 41 M0 m1 - cat cm 01.1 .tory lacquer solvent cannot be obtained from a It is evident from these data that the tem naphtha distillate with a naphthenic base by treatment at 14° F. (the usual treating tempera ture of solvent re?ning by the Edeleanu method). perature gradient extraction, Example 5 (b) - nor even at 0° F., but that it is possible to pro duce superior lacquer solvents by treating at ' 10 —14° F. and lower temperatures. Naphtha extracts which are manufactured in accordance with this invention by treating the stocks with sulphur‘ dioxide at substantially be low +14 degrew Fahrenheit, that is down to ~ —70 degrees Fahrenheit, are superior to the nor 55 gives the same yields and qualities of rates - ' and extracts as the normal treatment (Example 5 (0)). The extract obtained by rejection of the intermediate extract in Example 5 (a) has almost the same quality as the extracts obtained 70 in Examples 5 (b) and 5 (c), but the yield is somewhat lower, the reason for this lower yield being that the intermediate oil which was ob tained by cooling the original extract solution from zero to —B0° ‘F. still contains 1 we 4 2,118,771 amounts of aromatics and ole?nes. The inter mediate oil may, of course, be recycled into the extraction tower, thereby raising the extract yield. The invention is not restricted to vmotor fuels and lacquer solvents, but relates to the process of producing improved extracts and blends thereof suitable for these and other purposes; and where chilling the extract layer to a low temperature of the order of minus 60 to minus 70‘? F. to produce a second extract layer and separating out the latter, removing the SO: therefrom and blending the resulting extract with said low boil ing fraction. . 2. A process for securing a high octane num ber motor fuel from a naphtha, comprising sepa motor fuels and lacquer solvents are referred to . rating the naphtha into a low boiling fraction in the claims, it is to be understood that we in tend thereby to include any use to which the product is adapted. What we claim is as follows: 1. A process for securing a high ‘octane num tu ber motor fuel from a naphtha, comprising sepa rating the naphtha into a low boiling fraction and a high boiling fraction, treating the high boiling fraction with liquid-S02 at about 14-20° F. to produce a ra?inate layer and an extract layer, and a high boiling fraction, chilling the high 10 vboiling fraction to a low temperature of the order of minus 60 to minus 70° F. and extracting in the countercurrent manner with liquid-SO: in troduced at about 14-20° F., and blending the so-obtained extract with the low boiling fraction. 15 ERNEST TERRES. ERICH SAEGEBARTH. ,JOSEPH MOOS.