US2951034A

US2951034A - Desulfurization of hydrocarbons with a mixture of a group viii metal and group viii metal oxide or sulfide

Info

Publication number: US2951034A
Application number: US651587A
Authority: US
Inventors: Archibald P Stuart
Original assignee: Sun Oil Co
Current assignee: Sunoco Inc
Priority date: 1957-04-09
Filing date: 1957-04-09
Publication date: 1960-08-30
Anticipated expiration: 1977-08-30

Description

United States Patent A'MIXTURE- oFA GROUP'VIII'METAL AND new rm M rAL am, R U F D Archibald P. Stuart, Media, Pa., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey No Drawing. Filed Apr. 9, 1957, Ser. No. 651,587 11 Claims. (Cl. 208-244) This invention relates to the separation of sulfur compounds from petroleum, and more particularly to the use of special adsorbent material in order to accomplish such separation.

It is often desirable to separate sulfur compounds from petroleum fractions in which they normally occur. Thus, mercaptans may be removed from light fractions such as gasoline to eliminate undesirable odor and improve lead susceptibility. In the case of fuel oil, it is often desirable to remove mercaptans and other sulfur compounds in order to meet specifications as to sulfur content. Sulfur compounds may be removed from charge stocks for cat- 'alyt'icreforming processes employing platinum-containing catalyst, in order to avoid undesirable effects of ex,-

cessive amounts of sulfur on the catalyst.

"In the case of lubricating oils, sulfur compounds can be separated therefrom in order to obtain sulfur concent'r'ates which have valuable properties as anti-oxidants fof various petroleum fractions. It would be desirable to obtain a greater extent of sulfur removal and greater concentration of sulfur in the removed material than are obtainable with prior art methods of obtaining such concentrates. t i

The process according to'the present invention provides a highly effective manner of separating sulfur compounds from petroleum. The process is capable of being carried out at relatively low temperatures,for example in theappro'ximate'rang'e from 50 F.-to 300- F. The adsorbent material which is employed can be revivified for re-use by contact of the adsorbent with a desorbent liquid.

The process of the present invention involves; in'one embodiment, first contacting petroleum material in liquid phase With a solid porous adsorbent intimately associated with a 'group VlTI metal. It has been found thatthe presence ofthe group VIII metal promotes the selective adsorption of sulfur compounds. This permits a desulfurized hydrocarbon fraction to be obtained which'has a low sulfur content and is obtained in good yield. It also permits a sulfur concentrate to"be'obtaine'd' which has only a relatively small amount of hydrocarbon material associated therewith.

Group VIII metals generally are suitable for use inpreparing the desulfurizing agent. Nickel vis a preferred metal for such use, but others suchas cobalt, iron, plati: num, palladium, rhodium, etc. can also be employed.

By use of a desorbent liquid, it is possible to first desorb the hydrocarbon materials from the absorbent, and subsequentlydesorb sulfur compounds remaining on the adsorbent after the desorption of hydrocarbons. Usually, the amount of sulfur compoundsjdesorbed will be within the approximate range from 80 to 100 percent of thesul fur compounds in the charge. If desired, the desorption of hydrocarbons can be performed in stages, obtaining firsta fraction which is relatively concentrated with regard to saturated hydrocarbons (refractive index 11 about 1.46 to 1.50), then a mononuclear hydrocarbon concentrate (n about 1.50 to 1.54), then a dinuclear 2,951,034 Patented Aug. 30, 196Q ICE . 2 aromatic hydrocarbon concentrate (r1 2 about 1.54 to 1.59), and so forth. In this type of, operation, hydrocarbon fractions are obtained which, in, addition to being desulfurized, are improved for subsequent use as a result of change in their hydrocarbon composition.

Thus, for example, a saturated hydrocarbon material obtained in the desorption generally has improved properties, in the case of alubricating oil, with regard to viscosity index, or improved properties for use as a charge stock in a catalytic cracking as a result of removal of aromatic hydrocarbons therefrom. The automatic hydrocarbon concentrate obtained in'the desorption generally has improved properties for use as rubber processing oil or as -oil to be employed in the manufacture of carbon black. a

The absorbent material which is employed as desulfurizing agent comprises in apreferred embodiment a porous adsorbent and a group VIII metal in, intimate association. Any suitable manner of obtaining-intimate association of the group VIII metal and the porous adsorbent can be employed in this embodiment. For example, the porous adsorbent in-granular form can be impregnated'with an aqueous solution of a salt containing the metal in question, e.g. nickelnitrate, a chloroplatinate salt, etc; the impregnated adsorbentis then dried, calcined and reduced by contacting with hydrogen, thereby to obtain an adsorbent having the metal contained in the pores thereof. Another suitable manner of preparation involves forming, a paste containing intimately admixed finely divided porous adsorbent and fine particles of the metal, and extruding the paste to obtain particles com prising the adsorbent and metalin intimate association.

In a preferred embodiment, the desulfiurizing agent comprises a partiallyv oxidized or partially sulfided group VIII metal. It is believed that partial oxidation or sulfidation forms' metal oxide or metal sulfide at the most active sites of the metal, leaving the less active sites in the free metal state. The less active sites are sufficiently active to provide good adsorption of. sulfur compounds, but not so active as to make it difficult or impossible to desorb the sulfur compounds. Thus, a more satisfactory adsorption-desorption operation is obtained than in the case wherethe'metalis not partially oxidized or sulfided, and where sulfur compounds'are too strongly adsorbed at the most activesitesto be readily desorbed. In this embodiment, theweight ratio of free metal to metal oxide or sulfide-is preferably in' the, approximate t ee 09 m r i fe ab rltl; .1 2.4;1;

' The P i l a da iseq sulfide/ 911 s i be ref rmed in any'suitable manner, preferably by eorrtagting the nietalwith oxygen or a "sulfurcorrtaining material, eg.

Part of the metal a f h lasidsi 9 E lfi l P o h metal remaining inil l e n onfine j ta Instea of proceeding from theuncombined state .to the partially oxidized or sulfurized state, one can proceed frorn the combined state and convert part of the metal compound to the metallic state, cg. bypartial reduetionpf the metal oxide, part ofthe metal remairriug in the com binedstate. Mixtures of metal andmetaloxide or sulfur are kndwfi. e a a 1 .9 and in flie -light qfthe P spscifisafion-a P r ian sk l ed t e a isen. s leq suitable procedure'for preparing such mixtures. Q

A particularly good-'desulfurizing adsorbent for use according to the invention is one comprising metallic nickel, nickel Oxide or lfide. and amorous ads ben the total nickel content of the desu lfuri zingagent being within the approximate range, from 50 to 7 5 weight percent. I 30 to 60 weight percent. of thefdes llf rigipg agent in this embodiment comprises metallic niolgel, land 20 to 45. gh P e qmpusesni sel; qxisi g nic sel Sulfide or a xt re s sl oxide ani kel s lfide It has been found that this desulfurizing agent provides particularly good selective adsorption of sulfur compounds.

The desulfurizing agent employed according to the invention preferablycomprises a porous adsorbent in intimate association with the group VIII metal. However, it is also within the scope of the invention to use an agent, such as partially oxidized Raney nickel, which does not contain a separate porous adsorbent. Where a porous solid adsorbent is used, any such adsorbent can be employed. Such adsorbents are well known in the art as a class and include such materials as silica, gel, alumina, kieselguhr, bauxite, silica-alumina composites, fullers earth, pumice, clays, etc. In this embodiment, the metal is preferably partially oxidized or sulfided, though the metal can be substantially entirely in the uncombined state.

The desulfurizing agent according to the invention can be prepared for example by impregnating silica gel particles with aqueous nickel nitrate solution, drying the impregnated gel at 260 F., calcining at 800 F. to convert nickel nitrate to nickel oxide, and partially reducing at 800 F. with hydrogen and steam. If desired, the nickel can be reduced substantially entirely to the metallic state and then re-oxidized to convert part of the nickel to the oxide. Another illustrative preparation of the desulfurizing agent involves impregnation of an adsorbent with ammonium chloroplatinate solution followed by slow drying and heat decomposition of the deposited salt. Any other suitable manner of preparation can be employed, which produces an intimate association of the adsorbent with a group VIII metal.

Any suitable desorbent liquid can be employed to remove hydrocarbons and sulfur compounds from the adsorbent. It is known in the art to perform various separations of mixtures of material by adsorption-desorption technique, wherein a porous solid adsorbent is first contacted with the material to be separated in liquid phase and then with a desorbent liquid to selectively remove certain of the materials adsorbed on the adsorbent. Materials which can be employed as desorbent liquids in such processing are well known in the art and include such compounds as n-pentane, benzene, ethanol, isopropanol, thiophene, etc. Any of the known desorbent liquids can be employed in the process according to the invention. Examples of suitable desorbent liquids are disclosed in United States Patent No. 2,585,490, issued February 12, 1952, to I. L. Olsen. A plurality of desorbent liquids having increasing polarity can be employed in series if desired to remove successively the more strongly adsorbed components of the charge stocks.

In one embodiment, the charge oil, prior to contacting with the desulfurizing agent according to the invention, is given a pretreatment in order to remove therefrom the most strongly adsorbable sulfur compounds therein. These compounds may constitute for example about 1 to 15 percent of the total sulfur compounds in the charge. If these sulfur compounds are not previously removed, they may remain on the desulfurizing agent in the subsequent step since they are sometimes difi'icult to remove by ordinary desorption technique. By removing them in a pretreatment, it is possible to obtain operation in which substantially all of the sulfur compounds can be desorbed from the desulfurizing agent, and the latter re-used many times. Any suitable manner of removing the most strongly adsorbable sulfur compounds can be employed in the pretreating step. Thus, for example, the pretreatment can involve contacting the charge oil with a separate portion of the same adsorbent which is employed in the subsequent step or with some other adsorbent such as clay. Treatment with concentrated sulfuric acid. can also be employed to remove the most strongly adsorbable sulfur compounds. The desirability of the pretreatment will depend on the nature of the charge, and in some instances at least pretreatment will not be necessary.

The process of the invention can be applied to petroleum fractions generally such as gasoline, naphtha,

5 kerosene, fuel oil, lubricating oil, etc. Straight run or cracked fractions can be treated.

If desired, the contacting according to the invention can be performed in such manner that selective adsorption of sulfur compounds on the adsorbent is chtained, the hydrocarbon product being obtained as effluent from the adsorbent bed in the initial contacting, and the sulfur compounds remaining on the adsorbent being subsequently desorbed to obtain a single desorbed fraction. Preferably, however, the process is performed 5 in such manner that a plurality of desorbed fractions are obtained, including a desulfurized hydrocarbon fraction or fractions and subsequently a sulfur concentrate or concentrates.

The following example illustrates the invention:

The charge oil was a lubricating oil distillate derived from naphthenic base crude and having the following typical properties: specific gravity d of 0.9340, refractive index 11 of 1.5153, Saybolt Universal viscosity at 100 F. of 603 seconds and at 210 F. of 55 seconds, and sulfur content of 0.26 weight percent.

The desulfurizing agent was a mixture of nickel and nickel oxide in intimate association with kieselguhr and had the following composition: nickel 43.6%, nickel oxide 28.2%, silica 19.9%, alumina 3.0% and graphite 4.0%. One-eighth inch pellets were crushed to a powder in a nitrogen atmosphere. 500 grams of the powder were placed in a column to provide a 4 foot packed section.

A solution of 25 grams :of the charge oil in 50 ml. of n-pentane was introduced into the bed of desulfurizing agent. The following desorbents were used in series: 1450 ml. of 4% benzene in pentane, 1050 ml. of 10% benzene in pentane, 900 ml. of 24% benzene in pentane and 2000 ml. of 7% isopropanol in benzene. Effluent cuts were taken, desorbent stripped therefrom and the cuts composited into the fractions shown in the following table. Fraction 1 contained the first 10.6% of effluent oil, Fraction 2 the next 19.9%, and so' forth. The sulfur content of each composite fraction is shown, also the 45 cumulative weight percent of sulfur, based on total charge oil, contained in the efiiuent oil. Thus, Fraction 2 contained about 0.002% sulfur based on total charge, Fraction 3 about 0.003%, and so forth.

ft Wt ri a we tive Fraction Desorbent Wt. Percent Wt.

Percent Sulfur Percent O Sulfur l0. 6 0 30. 5 0.01 0. 002 47. 0 0. 02 0. 005 54. 3 0. 03 0. 007 61. 5 0. 04 0. 010 66. 5 0. 08 0. 014 76. 6 0. 11 0. 025 84. 8 0. 3 0. 050 90. 4 0. 57 0. 082 94. 5 1. 05 0. 125 24% benzene in n-pentane. 98.0 1. 86 0.208 12 7% lsopropanel in benzene. 99. 0 1. 86 0. 227

These results show that the first 90 percent of efiiuent contained about 0.082/ 0.26, or about 31.6 percent of the sulfur in the charge stock, representing about 68.4 percent desulfurization of 90 percent of the oil. In other werk, up to about 75 percent desulfurization of 90 percent of the charge was obtained. The total recovery of sulfur in desorbed fractions was about 0.277/0.26, or about 87 percent.

By way of contrast, only about 37 percent of the sulfur in the charge couldberecovered in desorbed fractions from Raney nickel using desorption technique essentially the same as that employed with the nickel-nickel oxide-kieselguhr adsorbent.

In the desorption of oil from the nickel-nickel oxidekieselguhr adsorbent, the refractive index of the efliuent oil increased steadily from about 1.48 for the first desorbed fraction to about 1.51 for Fraction 5 and to 1.6 at about Fraction 9, then decreased to about 1.58 at about Fraction 11, and rose again to about 1.59 at about Fraction 12.

In the preceding example, a plurality of desorbents having increasing polarity were employed in order to obtain a large number of desorbed fractions having gradually changing properties. It is to be understood that the entire desorption can if desired be performed with a single desorbing agent having constant composition, or with two desorbing agents in series, the latter having greater polarity, etc.

Thus, for example, 1000 ml. of 24% benzene in pentane is used in one embodiment as the sole desorbent, and a separation of sulfur compounds from hydrocarbons comparable to that disclosed previously is obtained. The sulfur compounds are in one embodiment desorbed in later portions of the same desorbent. In another embodiment, they are desorbed primarily with another desorbent having greater polarity, e.g. benzene, alcohol, mixtures of benzene and alcohol, etc.

Generally similar results, with regard to efficiency of sulfur separation, to those obtained in the above example, are obtained when treating other petroleum fractions such as gasoline, fuel oil, etc. Other group VIII metals can be employed in place of nickel.

The adsorption stage is preferably performed at relatively low temperature, e.g. 50 F. to 150 F., though higher temperatures, e.g. up to 300 F. or higher, can be employed if desired. The desorption stage can also be performed at relatively low temperature, e.g. 50 F. to 150 F., though higher temperatures, e.g. up to 300 F. or higher, favor desorption efliciency.

The process according to the invention provides in various embodiments new and improved manners of desulfurizing petroleum, reactivating the desulfurizing agent for re-use, recovering sulfur concentrates from petroleum,

and separating petroleum into fractions having different hydrocarbon composition. The sulfur concentrates obtained from various types of petroleum charge stocks in certain embodiments can be employed for any of the known uses of such concentrates.

The invention claimed is:

1. Process for removing sulfur compounds from petroleum hydrocarbons which comprises: contacting petroleum hydrocarbons in liquid phase at a temperature within the approximate range from 50 F. to 300 F. with a desulfurizing agent comprising a group VHI metal and a compound selected from the group consisting of an oxide and a sulfide of a group VIII metal, and contacting said agent with a desorbent liquid, thereby to desorb sulfur compounds.

2. Process for removing sulfur compounds from petroleum hydrocarbons which comprises: contacting petroleum hydrocarbons in liquid phase at a temperature within the approximate range from 50 F. to 300 F. with a desulfurizing agent comprising about to 60 weight percent of metallic nickel and about 20 to 45 weight percent of a compound selected from the group consisting of nickel oxide and nickel sulfide.

3. Process for removing sulfur compounds from petroleum hydrocarbons which comprises: contacting petroleum hydrocarbons containing sulfur compounds in liquid phase with a porous adsorbent in intimate association with a group VIII metal, thereby to adsorb sulfur compounds; and contacting said adsorbent with a desorbent liquid, thereby to desorb sulfur compounds.

4. Process according to claim 3 wherein said adsorbent containing adsorbed hydrocarbons and sulfur compounds is first contacted with a desorbent liquid to selectively desorb hydrocarbons and recover a first effluent containing hydrocarbons having reduced sulfur content, and is then contacted with a desorbent liquid to desorb a sulfur compound concentrate.

5. Process according to claim 1 wherein said petroleum hydrocarbons constitute a lubricating oil fraction.

6. Process according to claim 3 wherein said petroleum hydrocarbons constitute a lubricating oil fraction.

7. Process according to claim 1 wherein said agent is prepared by partially oxidizing saidmetal.

8. Process according to claim 1 wherein said agent is prepared by partially sulfiding said metal.

9. Process according to claim 1 wherein said temperature is within the approximate range from 50 F. to F.

10. Process according to claim 2 wherein said agent consists essentially of metallic nickel and nickel oxide.

11. Process according to claim 2 wherein said agent constitutes substantially the sole contacting agent.

References Cited in the file of this patent UNITED STATES PATENTS 809,087 Blackmore Jan. 2, 1906 1,944,170 Darlington Jan. 23, 1934- 2,073,578 Gwynn Mar. 9, 1937 2,273,298 Szayna Feb. 17, 1942 2,306,933 Burk Dec. 29, 1942 2,337,358 Szayna Dec. 21, 1943 2,559,323 Spillane July 3, 1951 2.756,182 Kimberlin et a1 July 24, 1956

Claims

1. PROCESS FOR REMOVING SULFUR COMPOUNDS FROM PETROLEUM HYDROCARBONS WHICH COMPRISES: CONTACTING PETROLEUM HYDROCARBONS IN LIQUID PHASE AT A TEMPERATURE WITHIN THE APPROXIMATE RANGE FROM 50*F. TO 300*F. WITH A DESULFURIZING AGENT COMPRISING A GROUP VIII METAL AND A COMPOUND SELECTED FROM THE GROUP CONSISTING OF AN OXIDE AND A SULFIDE OF A GROUP VIII METAL, AND CONTACTING SAID AGENT WITH A DESORBENT LIQUID, THEREBY TO DESORB SULFUR COMPOUNDS.