Oct. 22, -1946. E. w. s. NlcHoLsQN I-:rAL V2, ì ,690 - DESULPHURIZA'I‘ION 0F HYDROGARBON OILS Filed Dec. l0, 1943 0 Patented Oct. 22, 1946 2,409,690 UNITED STATES PATENT OFFICE ` DESULPHURIZATION OF \ DROCAR BON OILS Edward W. S. Nicholson and Aaron K. Redcay, Baton Rouge, La., assignors to Standard Oil Development Company, a corporation of Del aware Application December 10, 1943, Serial No. 513,680 6 Claims. (Cl. 196-24) 1 2 . This invention relates to the refining of petro leum distillates and pertains more particularly to» a method of removing sulfur constituents from said distillates. It has been proposed heretofore to remove sulfur compounds from petroleum distillates by passing the distillates’ in vapor form in an at mosphere of hydrogen through a bed of desulfur izing catalyst, such as nickel, alumina, or the like. During the course of the treatment a substan tial amount of the sulfur originally contained in the distillate is deposited. or absorbed on the cata lyst material. This makes it necessary to inter The oil vapors formed in the preheating and vaporizing furnace I3 continue through line I4 into the bottom portion of the treating chamber I5. A suspension of hydrogen and finely divided desulfurized catalyst is also introduced into the bottom of the treating‘chamber I5 through line IE and intermingles with 'the _oil to be treated. The treating chamber I5 is preferably provided with av perforated grid plate I'I positioned above the point of entry of oil vapors and catalyst hydrogen suspension to distribute the resulting mixture over the reaction chamber.V A mixture of hydrogen, oil vapors, and cata lyst passes upwardly through the perforated grid rupt the process periodically to remove the sulfur and to restore the activity of the catalyst. 15 I1 into the main body of the treating chamber. The velocity of the hydrogen and oil vapors The removal of the sulfur from the catalyst passing through the treating chamber is prefer may be accomplished by treating the catalyst ably controlled to permit the catalyst to segregate with hydrogen so as to `convert the sulfur into into a dense turbulent layer in the bottom portion hydrogen sulfide gas which may be subsequently ‘ ` ‘ recovered by passing the resulting gas through a 20 of the reaction chamber. The catalyst employed for removing the sulfur weak alkaline solution. It has also‘been `sug from the oil vapors may be any known desul gested to remove the sulfur by oxidation. When furizing catalyst such as finely divided metallic this is done, it is usually necessary to “subject” nickel supported on activated alumina or other the catalyst to a reducing treatment before being reemployed for further sulfur removal. ` 25 metal powders such ascopper or zinc, with or without carriers. The desulfurization treatment One of the primary objects of the present in is preferably carried out under a-.relatively low vention is to provide an improved process for pressure ranging from atmospheric to 200 pounds removing sulfur compounds from petroleum oils. per square inch and the temperature ofthe re A further object of the invention is to provide a continuous process for removing sulfur com 30 action zone may be between 400°'and 800° 1F., and preferably between 600° and r700" F. pounds from petroleum distillates. Other more speciñc objects and advantages will be apparent The oil vapors are retained in the treating chamber I5 in contact with the catalyst for a from theV detailed description of the invention period controlled to remove or materially reduce With the aboveobjects and advantages in view, 35 the' amount of sulfur compounds contained there in. The gaseous reaction products comprising the the invention will bebetter understood by refer treated oil vapors and hydrogen are removed from ence to the accompanying drawing which is a the upper end of the treating chamber I5 through diagrammatic illustration of an apparatus suit line IB and maybe passed to suitable separat able for carrying the invention into effect. Referring to the drawing, reference character 40 ing device such as a cycloneseparator I9 for re moval of entrained powder from the reaction I 0, located at the upper right hand portion of the products. The entrained catalyst powder sep drawing, designates a feed line through which arated from the reaction products in separator the oil to be treated is introduced into the equip I9 may be returned to the treating chamber ment. This oil is preferably a clean distillate stock such as a naphtha fraction, kerosene frac 45 through conduit 2 l. The vapors and gases after passing through the cyclone separator I0 are re tion, heating oil, light gas oil, or the like. moved through line 22 and- may beV subjected to The oil introduced through line `I0 is ’passed further treatment for removal of entrained pOw through a heat exchanger I I wherein it passes in der, as desired.` Following this, the reaction prod heat exchange relation with products from the process as later described. The oil after passing 50 ucts pass through heat exchanger II in indirect heat exchange with fresh feed as previously de through the preheater Il continues through line scribed. The products then continue through line I2 to a furnace I3 wherein the oil is vaporized 23 to cooler 24 in which the products are cooled and heated to the desired reaction temperature. This temperature may, for example, be of the to a temperature suf?cientjto condense the oil appearing hereinafter. order from 400° to 800° F. ~ ` ` ` ` ' vapors therefrom. « v ` > ‘ 2,409,690 3 4 The products from the condenser 24 are then passed to a product receiver 25 in which the treated liquid distillate is separated from the un reacted hydrogen and other gaseous materials. The treated distillate is withdrawn from the It has been found that there is an equilibrium between the sulfur which remains on the catalyst and the sulfur which is removed by the gas in the reactivating chamber 42. By employing a rela tively high proportion of hydrogen in compari product receiver 25 through line 26 and the gases are removed overhead from the product receiver son with the amount of sulfur contained on the catalyst the sulfur content of the catalyst may be reduced in the reactivating chamber 42 to a very low value. Gases resulting from the re tivating treatment in chamber 42 are withdrawn overhead therefrom through line 44 leading to a suitable separating device such as a cyclone sep arator 45 for removal of entrained catalyst there from and the separated catalyst may be re turned to the reactivator chamber 42 through line 46. The gases after passing through the cyclone separator 45 continue through line 4l to a heat exchanger 48 in which the gases pass in heat exchange relation to treated gases as later described'. The gases after passing through heat exchanger 48 are passed through line 48 to a cooler 5I in which the gases are cooled to tem through line 21. The treating chamber I 5 may be provided with an upwardly extending tube 28positioned in the bottom of the chamber for continuously with drawing catalyst from the chamber. The bottom of the tube 28 is in open communication with a vertical conduit 29 through which the catalyst is continuously withdrawn from the treating chamber and introduced into a stream of hydro gen containing gas. The vertical conduit 29 preferably forms a standpipe for generating a fluid pressure for circulating the finely divided catalyst through the treating chamber and the reactivating chamber to be later described. A small amount of an aerating gas should be main tained in admixture with the catalyst in the ver tical tube 28 to maintain it in a fluid condition capable of developing a ñuid pressure at the base thereof. To this end a small amount of an perature somewhat below the boiling point of water so that they may be subsequently scrubbed with a weak basic solution for the removal of hydrogen sulfide therefrom. aerating gas may be introduced at one or more The sulfur bearing gases after passing through the cooler 5I continue through line 52 to a scrubbing chamber 53 in which they pass ,spaced points along the column through lines 3I, 32 and 33. _ The column 29 may be provided with a Valve 30 in countercurrent contact with an aqueous solu 34 for controlling the level of the catalytic ma tion capable of absorbing or reacting with the terial maintained in the treating chamber I5, hydrogen sulfide present in the gas. For ex It is desirable to maintain the level of the dense ample, monoethanolarnine, diethanolamine, so layer of catalytic material in the treating cham ber I5 a substantial distance below the top of the chamber in order to reduce the amount of en trained solids contained in the reaction> products dium phenolate solutions may be used for this . purpose. The scrubbing liquid is introduced into the scrubbing tower 53 through line 54 and is re moved from the bottom of the tower through line withdrawn through line I8. The hydrogen-containing gas into which the 55. The sulfur-free gases consisting primarily catalyst from the column 28 discharges may be 40 of hydrogen are removed from the scrubbing introduced into the system through line 35 or it tower 53 through line 56 having the heat ex may consist in whole or in part of the gases re changer 48 located therein so that the treated moved from the product receiver 25. In the `gases pass in heat exchange relation with the latter case, a portion of the overhead products overhead products from the cyclone separator 45 from the receiver 25 withdrawn through line 2l as previously described. may be passed through line 36 to a compressor The treated gas after passing through the heat 3'I wherein it is recompressed to the desired pres exchanger 48 continues through line 5l 'and may sure for carrying out the reactivation of the be used as a carrier gas for returning the re catalyst. The compressed gas is then passed activated catalyst to the treating zone. through linev 38 which merges with line 35 lead Returning to the reactivating chamber 42, a ing to the furnace 39 in which the gas is heated tubular conduit 58 may be provided in the lower to a temperature suflicient to reduce the sulfur portion of the chamber for collecting the re contained on the catalyst. The heated hydro activated catalyst. The bottom of the reactivat gen-containing gas after passing through the ing chamber 42 connects with a vertical pipe 58 furnace 39 continues through line 4I into which for removing the reactivated catalyst from the the catalyst from the column 29 discharges, reactivating chamber. The vertical pipe 59 is The resulting suspension of hydrogen-con provided with a control valve 6I for regulating taining gas and catalyst continues through line the rate of removal of the reactivated catalyst 4I into the bottom of a reactivating chamber 42 from the chamber and for controlling the time of below a perforated grid plate 43, through which 60 residence of the catalyst within the chamber. the suspension passes into the body of the re The catalyst is preferably withdrawn from the activating chamber. chamber 42 at a rate suñicient to maintain the level of the dense catalytic mass within the The velocity of the hydrogen-containing gas passing upwardly through the reactivating cham chamber a substantial distance below the gas out ber 42 is also preferably controlled to permit the 65 let to reduce overhead entrainment as previously described in connection with the treating cham ber I5. The reactivated catalyst discharges through the control Valve 6I of the pipe 59 into the gas The temperature and pressure conditions maintained in the reactivating chamber 42 may 70 line 5l carrying the treated gas into the treating chamber I5. Any excess gas formed in the proc be substantially the same as those maintained ess may be removed through the line 82 and fresh in the treating chamber I5. For example, the hydrogen makeup gas may be introduced through temperature may be of the order from 400 to 800° line 35 as previously mentioned. From the above F. and the pressure between atmospheric and 200 pounds per square inch. 75 description it will be noted that the invention ñnely divided catalytic material to settle into a relatively dense layer in the bottom portion of the reactivating chamber. 2,409,690 5 provides a continuous process for effecting desul furization of hydrocarbon distillates wherein the form, continuously removing the hydrogen con~ taining` ga‘s containing the sulfur compounds desulfurizing catalyst is continuously circulated through a treating chamber and a reactivating from the reactivating zone, treating the gas so removed to remove the sulfurv therefrom and chamber. By controlling the rate of circulation thereafter returning the hydrogen containing gas of the catalyst through the two chambers the activity of the- catalyst in the treating zone may to said desulfurizing zone. i 3. A method of removing sulfur compounds from low boiling hydrocarbon oils which com prises passing a mixture of the oil in vapor form and hydrogen upwardly through a treating zone maintained at a desulfurizing temperature be be maintained at a higher level than in cases where catalyst is being maintained in static con dition in the treating zone and subsequently re generated in situ according to current practices. The present process also involves less degradation of the feed stock due to the fact that the activity and selectivity may be maintained at a higher tween 40() and 300° F., continuously introducing a stream of finely divided desulfurizing catalyst into the oil vapors passing through said zone, controlling the velocity of the vapors and gas passing through the treating zone to maintain a dense turbulent layer of finely divided catalytic contains a relatively low concentration of sulfur material in the bottom portion of said treating substantially no carbon is formed in the process Zone, keeping said oil vapors in contact with said and consequently the catalyst may be readily regenerated by means of hydrogen and without 20 finely divided catalyst for a period sui’ñcient sub stantially to reduce the amount of sulfur com the necessity of burning the carbon from the pounds contained in said vapors but insuflicient catalyst. to form substantial carbon deposits on the cata Having described the preferred embodiment, lyst, thereafter removing the treated vapors it will be understood that the invention embraces such other variations and modifications ‘as come 25 from the treating zone, continuously removing finely divided catalytic material containing sul within the scope of the accompanying claims. fur from the treating zone while the material We claim: has a relatively low concentration of sulfur, pass 1. A process for removing sulfur compounds ing the material so withdrawn into a reactivat from low boiling hydrocarbon oils which com prises continuously passing a mixture of hydro~ 30 ing zone, passing a gas consisting substantially exclusively of hydrogen through said reactivating carbon oil vapors and hydrogen through a treat zone in an amount and at temperature sufficient ing zone, contacting the oil vapors within the to convert the sulfur on said catalyst into gase treating zone with a desulfurizing catalyst, main ous sulfur compounds, contacting the catalyst taining the vapors in contact with the catalyst in the reactivating zone with said hydrogen con for a period and at a temperature suliicientV ma taining gas for a period sufficient materially to terially to reduce the amount of sulfur com reduce the sulfur content of the catalyst obtained pounds contained in said oil but insufficient to therein, thereafter withdrawing the reactivated form substantial carbon deposits onthe catalyst, catalyst and returning the same to said ñrst thereafter removing the treated vapors from the level. By continuously withdrawing the catalyst from the treating chamber while the catalyst treating zone, continuously removing catalytic 40 named treating zone. 4. In the process deñned by claim 3, the fur material from the treating zone while said mate ther improvement which comprises treating the rial contains a relatively low concentration of gas removed from the reactivating zone to re sulfur, passing the catalyst so removed through move the sulfur compounds therefrom and there a reactivating zone, treating the catalyst within 45 after returning the same to the ñrst named treating zone. stantially exclusively of hydrogen in an amount the reactivating zone with a gas consisting sub and at temperature sufiicient to remove the sul fur from said catalyst and returning the desul furized catalyst to the treating zone. 2. A process for removing sulfur compounds from lower boiling hydrocarbon oils which com prises passing a mixture of said oil in vapor form and hydrogen through a desulfurizing zone containing an active desulfurizing catalyst, main taining the oil vapors in contact with the catalyst at elevated temperature for a period sufficient materially to reduce the amount of sulfur com pounds contained in said vapors butA insufficient to form substantial carbon deposits on the cata lyst, thereafter removing the treated vapors from the desulfurizing zone, continuously removing catalyst containing sulfur from said zone while the catalyst has a relatively low concentration of sulfur, passing the sulfur containing catalyst so withdrawn into a reactivating zone, treating said catalyst within said reactivating zone with a gas consisting substantially exclusively of hydro gen, controlling the temperature and the contact time within the reactivating zone to convert the sulfur contained on said catalyst into a gaseous 5. In the process defined by claim 3, the fur ther improvement which comprises segregating a hydrogen containing gas from the treated oil 50 vapors removed from the treating zone and pass ing the hydrogen containing gas so segregated through said reactivating zone. 6. A continuous method of reactivating a de sulfurizing catalyst used for the desulfurization 55 of petroleum distillates which has become con taminated in a treating zone with sulfur depositsV but is substantially free from carbon deposits, which comprises continuously removing the cata lyst containing sulfur deposits from the treating 60 zone, passing the catalyst so withdrawn into a reactivating zone, treating the catalyst within the reactivating zone with a gas consisting substan tially exclusively of hydrogen, said gas being pres ent in an amount and at a temperature suñicient 65 to remove the sulfur deposits from said catalyst, and returning the reactivated catalyst to the treating zone. . EDWARD W. S. NICHOLSON'.` 70 AARON K. RE'DCAY.