US2647857A - Hydrodesulfurization process - Google Patents

Description

Aug. 4, 1953 w. A. HoRNE HYDRODESULFURIZATION PROCESS Filed Oct. 4, 1949 @W Mwmmmu Zmruomnm ma mmwmm@ @REMO M OH W NH @dl mL O( iL M G N I l C .l N@ m w ,ON o A N R N P m QW m @@N @NN www @mw PGN @NN )@ON v0 00 :mwN @NN J MmmN T @M d @0N NNN @b mwN @0N @NN NNN NoN www NGN! CNN! @Q1 Wmv R R R R m u m 1 o 1 m A o 1 o o w w ww w v w v ww @n @n m 1 o A o. A o. A o. A o. n c. o A o m N N N N N N N m N N N E N N N R R R R R `R R @TNI bw ENI @nl @Nn 10N @0N WANN WANN NHN WOW Ww/ .OOM @nw NN. .GN NmN Mw mw 2mm L \M NNW mwmxwlmnmmww c@ NL www@ 00N NNN 00N 9N @NH @Q Q 4 0N NN gm O/N|\.I|f @AWN :Il ANW f. TQM MOH NNN -O A f` Il @NN @NN @mf Wwf A0 YVlLLI/M f5- BORNE f1', ATTORNEY Patented Aug. 4, 1953 HYDRODESULFURIZATION PROCESS William A. Horne, Oakmont, Pa., assignor to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware Application October 4, 1949, Serial No. 119,513

4 Claims. (Cl. 196-26) This invention relates to a hydrodesulfurization process and more particularly to a method of carrying out hydrodesulfurization Without undue consumption or" hydrogen.

The contact or adsorption hydrodesulfurization process has furnished the rener of crude petroleum with one of the most eihcient methods of removing sulfur from sulfur-bearing charge stocks. As disclosed in U. S. applications Serial Nos. 699,671 and 699,672, led September 27, 1946, by W. A. Horne and J. F. Junge, now Patents 2,516,876-7, dated August 1, 1950, this process consists in contacting a petroleum hydrocarbon and hydrogen-containing gas mixture in the presence of a contact agent such as one comprising an iron group metal oxide such as nickel oxide on a carrier at an elevated temperature and pressure. During the course of the process nickel oxide is converted to nickel sulde thereby absorbing the sulfur content of the petroleum hydrocarbon charge upon the contact agent. The process is continued until substantial amounts of hydrogen sulde appear in the eiiluent at which time the process is stopped and the contact agent regenerated to substantially its original form. This regeneration comprises an oxidation in which the nickel sulfide formed during the hydrodesulfurization process is oxidized back to nickel oxide. Following the regeneration the system is repressured and once again put on-stream, although in some cases it may be desirable to prereduce the contact agent with a hydrogencontaining gas prior to introducing the petroleum hydrocarbon charge.

Several diiiiculties have been encountered in the application of this type process. Thus, the process as practiced prior to the present invention utilizes but approximately one-third to onehalf of the iron group metal content of the contact agent as an absorption medium. As a consequence, about one-third to one-half of the iron group metal content is converted to iron group metal sulfide, whereas the remainder plays virtually no part in the hydrodesulfurization.l Moreover, the great percentage of the iron group metal content that was converted to sulde lies in the upstream or upper end of the hydrodesulfurization reactor, whereas the major portion of the unused contact lies in the downstream or lower end of the reactor. During regeneration the iron group metal sulfide such as nickel sulfide in the upper part of the reactor is oxidized according to the following equation:

The SO2 so formed does not react with any NiS which it may encounter in the contact bed, but reacts with the nickel or nickel oxide of the original contact, or which is formed during the regeneration, int he following manner:

Thus, a considerable portion of the nickel which has not become converted into NiS during the onstream period is present as NiSOwA at the end of the regeneration treatment. When this contact is again put on-stream or prereduced the NiSO4 will consume ve times as much hydrogen as does the ordinary NiO as shown in the following equations:

NiSO4-l-5H2 Ni|-4I+I2Ol-II2S NiO-l-HzNi-i-I-IzO This results in an undue consumption of hydrogen without any economic gain being achieved.

In addition to the foregoing, there is the inefcient contact Waste due to the fact that from one-half to two-thirds of the metal content of the contact bed is not utilized. Thus a considerable portion of the contact (e. g., that portion not converted to NiS) will be reduced to the free metallic state and thus will consume hydrogen without realizing any corresponding economic gain. This free metallic portion of the bed will be oxidized back to the oxide state during the course of the regeneration and thus will be continuously reduced and reoxidized without serving its intended function as a sulfur absorbing agent. For these reasons it is highly desirable to operate the process so as to obtain as complete a sulfurization of the iron group metal content of the contact agent as is possible, consistent with the economics of the other process variables.

An object of the present invention is to re-duce the formation of sulfates in an adsorption hydrodesulfurization contact bed,

Another object of the present invention is to provide a method whereby the amount of hydrogen consumed in a hydrodesulfurization process is materially reduced.

A further object of this invention is to provide a method wherein a high percentage of the metal [content of an adsorption hydrodesulfurization process bed is utilized.

Further objects will appear hereinafter.

These and other objects are achieved by the process of the present invention which comprises passing petroleum hydrocarbons and a hydrogencontaining gas at an initial space velocity into a chamber containing a contact agent selected from the group consisting of the iron group metals, iron group metal oxides, and mixtures thereof supported on a carrier, reducing the space velocity during such passage, oxidatively regenerating said contact agent, and restoring it to substantially its original form, thereupon replacing the system onstream by introducing hydrogen-containing gas and petroleum hydrocarbons into the chamber.

The present application is similar to the aforementioned Horne and Junge applications as regards the operating conditions. The present application is an advance over the above applications in that I have discovered that by commencing with an initially relatively high space velocity and reducing the space velocity as the contact agent absorbs increasing quantities of sulfur, the deleterious reactions involving sulfate formation concomitant with the preferential sulfurization of the up-stream portion in a hydrodesulfurization contact bed reactor are virtually eliminated. Depending upon the nature of the charge stock, temperature of reaction, and other process variables the initial, average and minimum space velocities will vary. Broadly, I have found that the initial space velocity may be from about 1 to 8 liquid volumes of charge per hour per volume of Contact agent. The final space velocity range may be varied from about 1A?, to 2 volumes of charge per hour per volume of contact agent. Within these ranges I have found rthat with low boiling charge stocks such as those normally liquid petroleum fractions having an ASTM end point below 600 F., such as straight run or cracked gasolines and naphtha, an initial space velocity range of 4 to 8, and a final space velocity range of 1 to 2 is to be preferred; For crude cils, and high boiling stocks in general, an initial space velocity of the order of 1 to 4 Volumes of charge per hour, per volume contact agent should be employed. This should be periodically or continuously reduced as the contact absorbs sulfur until a minimum space velocity of the order of 0.25 to 1 volume of charge per hour, per volume of contact agent is achieved.

In addition to the foregoing effect on sulfate formation the application of my process permits a far greater percentage of sulfur absorption to be achieved with a given size contact bed. This is due to the fact that a given unit of contact agent absorbs more sulfur during the on-stream cycle period than occurred in prior art processes.

The reaction takes place at varying temperatures, pressures and space velocities with the optimum conditions depending on the type charge stock that is used. For example, with low boiling hydrocarbons such as those normally liquid petroleum fractions having an ASTM end point below 600 F., such as straight run or cracked gasolines and naphtha, the temperatures will usually lie between 600 and 800 F. I have found that at temperatures below 600 F., the desulfurization activity of the Contact diminishes whereas with temperatures higher than 800 F. excessive cracking reactions result in decreased product recovery and rapid coke formation which deactivates the contact. I have further found that the optimum pressures lie between 100 and 500 p. s. i. g. At pressures below 100 p. s. i. g. the partial pressure of hydrogen is not sufficient to maintain desulfurization activity nor to suppress cracking reactions which result in coke formation. Increasing the pressure above 500 p. s. i. g. results in only a slight incremental gain in desulfurization, and a decrease in the bromine number of the end product gasoline and is thus not commercially desirable.

This invention can be applied with exceptional success to high boiling petroleum hydrocarbon oils such as total crude, topped crude or reduced crude, i. e., petroleum oil resulting from removal of all or some of the straight run fractions such as gas, gasoline, kerosene, naphtha, furnace oil, gas oil, etc., which are normally removed from the above-defined total crude by the process of atmospheric and/or vacuum topping or distillation. Charge stocks such as total crude which has been diluted or admixed with lower boiling straight run or cracked petroleum fractions including gases are also included. Diluents of this kind may be required in processing low gravity crudes such as some of those from Mississippi as well as those from Kuwait. Diluents may also be necessary and preferred in desuliurizing topped or reduced crudes. The purpose of this diluent is to assist vaporization of the heavier constituents of the charge stock. In some cases it may be desirable to admix steam with the charge stock to assist Vaporization. Preferred operating conditions for the aforementioned high boiling petroleum hydrocarbons may vary within certain ranges depending upon the charge stock.

I have found the optimum temperature range to be from '750 to 950 for high boiling petroleum hydrocarbons. At temperatures below '.750" F. the desuliurizing activity of the contact diminishes whereas at temperatures greater than 950 excessive cracking actions result in decreased product recovery and rapid coke formation which deactivates the contact. have further ascertained the preferred pressure range to be between and 1000 p. s. i. g. With pressures below 10G p. s. i. it appears that the partial pressure of hydrogen is not sufficient to maintain desulfurizing activity nor to suppress cracking reactions which result in coke formation. Increasing the pressure above 1000 p. s. i. g. results in only a slight incremental gain in desulfurization and isthus not commercially desirable. I have found that best results are obtained with a hydrogen ratio to petroleum hydrocarbon of between 800 s. c. f/bbl. to 20,000 s. c. f./bbl. or more. As disciosed in the aforementioned Horne and Junge applications the Contact may comprise a substantial amount of an iron group metal oxide, i. e., nickel, iron or cobalt oxides supported on a carrier, such as alumina. However, while the iron group metal oxides form the preferred contacts for my invention other contact agents may be utilized such as the elemental iron group metals, i. e., nickel, iron, or cobalt; or mixtures of iron group metals and their oxides, such as nickel-nickel oxide, iron-iron oxide, cobalt-cobalt oxide. As carriers I have found that any of the common substances employed for this purpose in the petroleum industry are applicable such as kieselguhr, silica-gel, aluminum silicates, silica-alumina, Alfrax, Magnesol, Porocel, bauxite, diatomaceous earth, etc. Contact agents may be prepared by any of the known methods such as single or multiple impregnation, coprecipitation, adsorption from a colloidal solution, etc.

The present process is best understood by an examination of the accompanying gure. The reactors shown in the accompanying ligure, namely reactors Nos. I-VIII contain beds of contact agent which comprise, as indicated above,

a member of the group selected from the group consisting of the iron group metals, iron group metal oxides, and mixtures thereof supported on a carrier. As will be explained hereinafter these reactors are at various stages of the process cycle such as being ori-stream, or in the regeneration stage. Accordingly, the chemical composition of the contacts Will vary among the reactors since some of them will be more or less sulded in relation to the others.

A crude charge, such as a West Texas crude, enters the system through line 0 passes through heater i2 into line H5. Hydrogen-containing gas enters the system through line |5, passes through heater I8 into line 2Q. From line hl the crude charge passes through line 22, valve 24, line 26, line 28 into reactor No. I. Since in the present example reactor I is at the initial portion of its on-stream cycle the charge is passing through reactor I at a relatively high initial space velocity such as of the order of 2.0 volumes of charge per hour per volume of contact agent. The crude charge is accompanied into reactor No. I by the hydrogen-containing gas which has passed from line through line 30, valve 32 and line 28. In reactor No. I the crude charge is hydrodesulfurized and the sulfur contained therein is absorbed by the contact material to form iron group metal sulde. The hydrodesulfurization products are removed from reactor No. I by line 34 and pass through line 35, valve 38 into line 40. From line 40 the products are removed from the system where they may undergo subsequent rening steps such as distillation, etc.

Were reactor No. I being regenerated, regeneration gas would enter reactor No. I after having passed through line 43, heater 53, line 52, line 3|, valve 33 and line 28. These regeneration gases after having accomplished the regeneration would be removed from reactor No. I by line line 35, valve 3?, line 30, from which they would enter line 66 and would be removed from the sysn tem by means thereof.

For the purposes of the present example reactor No. II is in the latter stages of the regeneration cycle. rIhe regeneration treatment is effected by regeneration gas entering the system through line d8 from Which it passes through heater 50, line 52, line '54, valve 56, line 58 and line t5 through reactor No. 1I. This regeneration gas comprises an oxidative gas, that is, a gas such as oxygen or one containing oxygen, such as air. The regeneration gas products which include the sulfur formerly on the contact, but now in the form of sulfur dioxide, are removed from reactor No. II by means of line 60 and pass through line 62, valve 54, line G5 into line 5B from which they are removed from the system. rhe sulfur dioxide in this gas may be recovered in the conventional manner such as by ammonia absorption and stripping. The sulfur dioxide free regeneration oir-gas may then serve to dilute the iirst regeneration gas admitted to the reactors. After regeneration is complete, which may readily be determined by the fact that the rate of oxidation becomes quite small, the oxidizing gas is shut oir and the reactor steamed to remove any oxygen which may be present. Where prereduotion is desired, valve 56 is then closed and hydrogen or hydrogen-containing gas is introduced into reactor No. II through valve IM so as to prereduce the contact bed. Where prereduction is not contemplated, valve 58 as well as valve d4 may be opened following the aforementioned steam treatment and crude charge passed from line 10 through line 12, line 46 and into reactor No. II along with the hydrogen from line 42. Were reactor No. II ori-stream, the crude charge and hydrogen mixture would be passing through reactor No. II in the manner indicated above, and the hydrodesulfurization products would be removed by means of line 60, line 74, valve 16, line 'I3 and pass into line 5) Where they would be removed from the system.

In the present example reactor No. III is like wise assumed to be in the regenerative stage as is reactor No. II, although reactor No. III unlike reactor No. II is in the central rather than the latter portion of the regenerative cycle. Thus, regeneration gas is passing through reactor No. III from line 52 by means of line 80, valve 52, line i, line and leaving reactor No, III by means of line 88, line 90, valve 92, line Sii into line 65. Were reactor No. III on-stream, crude charge would be entering from line |4 by means of line 95, valve 95, line |00 and line 5?. Hydrogen-containing gas would be entering reactor No. III from line 20 through line |02, valve |013 and line 86. The hydrodesulfurization products from reactor No. III would be leaving reactor No. III from line 88, line |06, valve |08, line H0 from which they would pass into line 4Q and out of the system.

Reactor No. IV is at the early stage of the regenerative cycle. This portion of the cycle includes the depressuring and purging of the reactor such as by vacuum and/or with an inert substance such as steam (introduced by means of lines and valves not shown) so as to recover the valuable hydrocarbons which remain in the contact bed. These valuable hydrocarbons and the inert substance are removed from reactor No. IV by means of line ||2 and pass through lines, valves and a condenser (not shown) so as to remove the inert substance after which the valuable hydrocarbons are passed into line H4, valve Ii, line ||8 and then into line 40 from which they leave the system. Following the purge, oxidative regenerative gas such as oxygen or an oxygen-containing gas such as air is introduced from line 52 through line |20, valve |22, line |24, line |26 into reactor No. IV. This regenerative gas leaves reactor No. IV by means of line H2, line |28, valve |30, and line |32 from Which it passes to line 56 and out of the system.

Were reactor No. IV ori-stream, crude charge Would pass from line I4 through line |34, valve |36, line |38, line |26 into reactor No. IV, and the hydrogen-containing gas would enter reactor No. IV through line |20, valve |42 and line |25.

Reactor No. V is in the last stage of the process cycle. Thus, in the present example utilizing a West Texas crude the space veloci-ty of the charge through the reactor would be of the order oi' 0.5. The crude charge is entering reactor No. V from line I4, through line |46, valve |45, line Hi8, and line |50. The hydrogen-containing gas is entering reactor No. V from line 20 through line |52, valve |5fi and line |50. The hydrodesulfurization products are removed from reactor No. V by means of line |56, line |58, valve |60, and line |52 from which they are passed to line @il and then out of the system. The termination of the On-stream cycle Will vary With diierent charge stocks and differing reaction conditions.

In most cases the reaction Will be terminated when substantial amounts of hydrogen sulfide appear in the eiiiuent at the lowest space velocity. However, consideration should be given in many cases to the extent of sulding of the contact and in these situations the process should be continued until the contact has been substantially suliided to the desired degree. I have found that in most cases it is desirable to achieve a sullding of the contact of the order of l to 90 per cent. Were reactor No. V being regenerated, regenera tion gas would be entering reactor No. V from line 52 by means of line |64, valve |56, line |68 and line |55. The regeneration gas would be removed from reactor No. V by means of line |56, line H6, valve |l2, line |l4 from which it would enter line 36 and would be removed from the system by means thereof.

Reactor No. VI is on the latter half of the onstream cycle and accordingly crude charge is entering reactor No. VI from line |4 by means or" line H6, valve |78, line |80 and line |82. Hydrogen-containing gas is entering reactor No. VI from line 25 by means of line |84, valve |86 and line |82. The space velocity of the charge should be of the order of 0.5. The hydrodesulfurization products from reactor No. VI are removed by means of line |88, line |95, valve |92, line |94, from which they enter line 4|] and are removed from the system. Were reactor No. VII being regenerated, regeneration gas would enter reactor No. VI from line 52 by means of line ISF, valve |96, line 200 and line |32. These regeneration gases would be removed from reactor No. VI by means of line |88, line 202, valve 2513, line 255 from which they would enter line 65 and would oe removed from the system by means thereof.

Reactor No. VII is in the central portion of the on-stream cycle and the crude charge enters it from line |4 by means of line 208, valve 2|6. line 2|2 and line 2M. Hydrogen-containing gas is entering reactor No. VII from line 20 by means of line 2%6, valve 2|8 and line 2M. The space velocity of the charge through reactor No. VII should be of the order of 1.0. The hydrodesulfurization products are removed from reactor No. VII by means of line 220, line 222, valve 224, and line 225 from which they pass into line 46 and out of the system. Were reactor No. VII being regenerated the regenerationv gas would enter reactor No. VII from line 52 by means of line 225, valve 236, line 232 and line 2|4. This regeneration vgas would be removed from reactor No. VII by means of line 226, line 234, valve 235, and line 238 from which it would enter line B6 and thereby be removed from the system.

Reactor No. VIII is on the rst half of the onstream cycle. Accordingly, crude charge is entering reactor No. VIII from line I4 by means of line 24U, valve 242, line 244 and line 246. Hydrogen-containing gas is entering reactor No. VIII from line 20 by means of line 248, valve 250 and line 246. The space velocity of the charge through reactor No. VIII should be of the order of 1.5 I-Iydrodesulfurization products are being removed from reactor No. VIII by means of line 252, line 254, valve 256, and line 258 from which they enter line 40 and are removed from the system by means thereof. Were reactor No. VIII being regenerated regeneration gas would enter reactor No. VIII from line 52 by means of line 26e, valve 262, line 263, and line 246. The regeneration gas would be removed from reactor No. VIII by means of line 252, line 253, Valve 255, and line 251 and would enter line 66 from which it would be removed from the system.

The method of operation employed in the following example and in the accompanying gure may be more fully understood by referring to the following table which indicates the space velocity for each hour of run in each reactor, and the periodic reduction in space velocity as the contact becomes increasingly sulded. Thus, the foregoing example embodied in the first hour of the run shown in the following table, i. e., reactor No. I had a space Velocity of 2.0 reactor Nos. II, III, IV were in the regenerating stage of the cycle, reactor Nos. V and VI had space velocities of 0.5, reactor No. VII had a space Velocity of 1.0, and reactor No. VIII had a space velocity of 1.5. As the run progresses it will be seen from the table below that the space velocity in reactor No. I decreases, and that reactor No. II goes from the regeneration to the on-stream cycle, etc.

TABLE I Hourof Ruu l 2 3 4 5 6 7 8 Reactor No. SPACE VELOCITY I 2.0 1.5 1.0 0.5 0.5 R R R 2.0 1.5 1.0 0.5 0.5 R R R R 2.0 1.5 1.0 0.5 0.5 R R R R 2.0 1.5 1.0 0.5 0.5 0.5 R R R 2,0 1.5 1.0 0.5 0.5 0.5 R R R 2.0 1.5 1.0 1.0 0.5 0.5 R R R 2.0 1.5 1.5 1.0 0.5 0.5 R R 2.0

R= Regeneration.

Example I .--A West Texas crude charge having the inspection appearing below in Table II was hydrodesulfurized according to my method with a contact consisting of 22 per cent Ni as NiO on Houdry cracking catalyst at a temperature of 850 F. and pressure of 500 p. s. i. g. The space velocity conditions were similar to those utilized in Table I. The inspection of the crude charge and product appears in Table II.

TABLE II Hydrodesulfum'eation of West Temas crude inspection of charge and typical liquid product Charge Product Gravity, API Distillaticn. "F I. B. P..

1 Carbon Residue, Bottom. PercentY Flasi OC "F B. W Sulfur, IeiV (Bo Salt, iba/1.000 bbl The process of the present invention is not to be construed as limited to a system in which eight reactors are employed, since the foregoing description was given for illustrative purposes solely. Thus, a larger or smaller number of reactors may be utilized and the space velocity employed during the on-stream portion of the cycle arranged so as to conform to the number of reactors in the system. This permits the process to be conducted in a continuous manner so that some of the reactors will be in the regenerative stage of the cyclewhile the other reactors are on-stream. If desired, the process'may be conducted in an intermittent manner such as with but one reactor or having all of the reactors simultaneously Von-stream or in regeneration. However, the continuous method of operation in which some reactors are on-stream, While others are in the regenerative phase, is to be considered the preferred embodiment of my invention. Other process variables readily apparent to one skilled in the art, such as the use of a single heater for the hydrogen-containing gas and the charge, etc., are also to be considered within the scope of my invention.

In the contact hydrodesulfurization reaction the charge stock will always be at least partially in the vapor state but depending upon the boiling point of the specic charge stock and the physical conditions of the reaction the phase status may vary, Thus, in some instances the hydrodesulfurization reaction will be effected with the charge stock totally in the vapor state, Whereas in other cases a mixed vapor-liquid phase will be utilized in the reaction.

The use of the present invention has the beneflcial effect of reducing sulfate formation in the Contact bed during regeneration. Through the prevention of this sulfate formation there is a material reduction in the amount of hydrogen consumption during the on-stream or prereduction cycle following regeneration since the sulfate which would otherwise be present consumes five times as much hydrogen as does the normal oxide form. Furthermore, the utilization of this invention results in a greater degree of contact effectiveness being realized, i. e., an increased percentage of absorption of sulfur compound on the contact is effected during the on-stream cycle with a concomitant saving of hydrogen, which otherwise would be expended in the reduction of the initial oxide contact to the free metal contact.

In the following claims the expression oxidatively regenerating said contact agent and restoring it to substantially its original form is to be understood as covering cases in which treatment with gases other than oxidative gases are necessary to restore a contact to its original form. Thus, in the case of certain elemental metal or elemental metal-metal oxide contacts the prereduction treatment with hydrogen following the oxidative regeneration may prove desirable and this additional treatment is to be construed as embodied in the following claims.

What I claim is:

1. The process for hydrodesulfurizing a petroleum hydrocarbon which comprises passing the petroleum hydrocarbon and a hydrogen containing gas into an enclosed chamber which contains a contact agent selected from the group consisting of iron group metals, iron group metal oxides and mixtures thereof, such passage taking place at an initial space velocity (volumes of charge per hour per volume of contact agent in the entire enclosed chamber), reacting sulfurous material in the petroleum hydrocarbon with the iron group portion of the contact agent to form iron group metal sulfide, reducing the space velocity (volume of charge per hour per volume of contact agent in the entire enclosed chamber) to below the initial space velocity when a substantial amount of iron group metal sulfide has been formed, whereby the charge is in any given portion of the contact agent a longer time than at 10 the initial space velocity, oxidatively regenerating the vcontactvagent to restoreit substantially to its original form and again placing the system oli-stream by introducing hydrogen containing gas and petroleum hydrocarbon into the chamber.

2. The process for hydrodesulfurizing a petroleum hydrocarbon which comprises passing the petroleum hydrocarbon and a hydrogen containing gas into an enclosed chamber which contains a contact agent selected from the group consistingfof iron group metals, iron group metal oxides and mixtures thereof at an initial space velocity of between about l and 8 liquid volumes of charge per hour per volume of contact agent in the entire enclosed chamber, reacting sulfurous material in the petroleum hydrocarbon with the iron group portion of the contact agent to form iron group metal sulfide, reducing the space velocity when a substantial amount of iron group metal sulde has been formed, to below the initial space velocity and to between 0.25 and 2.0 liquid volumes of charge per hour per volume of contact agent in the entire enclosed chamber, whereby the charge stock is in any given portion of the contact agent a longer time than at the initial space velocity, oxidatively regenerating the contact agent to restore it substantially to its original form and again placing the system on-stream by introducing hydrogen containing gas and the petroleum hydrocarbon into the chamber.

3. The 'process for hydrodesulfurizing a high boiling petroleum hydrocarbon which comprises passing the high boiling petroleum hydrocarbon and a hydrogen containing gas into an enclosed chamber at a temperature between about 750 F. and 950 F. and a pressure of between about and 1000 p. s. i., which chamber contains a contact agent selected from the group consisting of iron group metals, iron group metal oxides and mixtures thereof, such passage taking place at an initial space velocity (volumes of charge per hour per volume of contact agent in the entire enclosed chamber), reacting sulfurous material in the petroleum hydrocarbon with the iron group portion of the contact agent to form iron group metal sulfide, reducing the space velocity (volume of charge per hour per volume of contact agent in the entire enclosed chamber) to below the initial space velocity when a substantial amount of iron group metal sulfide has been formed, whereby the charge is in any given portion of the contact agent a longer time than at the initial space velocity, oxidatively regenerating the contact agent to restore it substantially to its original form and again placing the system on-stream my introducing hydrogen containing gas and high boiling petroleum hydrocarbon into the chamber.

4. The process for hydrodesulfurizing a high boiling petroleum hydrocarbon which comprises passing the high boiling petroleum hydrocarbon and a hydrogen containing gas into an enclosed chamber at a temperature between about 750 and 950 F. and pressure between about 100 and 1000 p. s. i., which chamber contains a contact agent selected from the group consisting of iron group metals, iron group metal oxides and mixtures thereof, at an initial space velocity of between about l and 4 liquid volumes of charge per hour per volume of contact agent in the entire enclosed chamber, reacting sulfurous material in the petroleum hydrocarbon with the iron group portion of the contact agent to form iron group metal sulfide, reducing the space velocity when a Substantial amount of iron group metal sulde of charge per hour per volume of Contact agent in 5 the entire enclosed chamber, whereby the charge stock is in any given portion of the Contact agent a longer time than at the initial space velocity, oxidatively regenerating the contact agent to restore it substantially to its original form, again placing the system ori-stream by introducing hydrogen containing gas and the high boiling hydrocarbon into the chamber.

A. #I-IORNE.

References cited 1n the me of this patent UNITED sTATEs PATENTS Number Name Date Dormon Oct. 27, 1931 Gwynn Mar. 9, 1937 Lyman et al. Jan. A10, 1939V Gwynn Oct; 31939 Szayna Feb. 17, 1942 Lovell Aug. 29, 1944 Matuszak e June 19, 1945 Horne et a1 Aug. 1, 1950

Claims (1)

1. THE PROCESS FOR HYDRODESULFURIZING A PETROLEUM HYDROCARBON WHICH COMPRISES PASSING THE PETROLEUM HYDROCARBON AND A HYDROGEN CONTAINING GAS INTO AN ENCLOSED CHAMBER WHICH CONTAINS A CONTACT AGENT SELECTED FROM THE GROUP CONSISTING OF IRON GROUP METALS, IRON GROUP METAL OXIDES AND MIXTURES THEREOF, SUCH PASSAGE TAKING PLACE AT AN INITIAL SPACE VELOCITY (VOLUMES OF CHARGE PER HOUR PER VOLUME OF CONTACT AGENT IN THE ENTIRE ENCLOSED CHAMBER), REACTING SULFUROUS MATERIAL IN THE PETROLEUM HYDROCARBON WITH THE IRON GROUP PORTION OF THE CONTACT AGENT TO FORM IRON GROUP METAL SULFIDE, REDUCING THE SPACE VELOCITY (VOLUME OF CHARGE PER HOUR PER VOLUME OF CONTACT AGENT IN THE ENTIRE ENCLOSED CHAMBER) TO BELOW THE INITIAL SPACE VELOCITY WHEN A SUBSTANTIAL AMOUNT OF IRON GROUP METAL SULFIDE HAS BEEN FORMED, WHEREBY THE CHARGE IS IN ANY GIVEN PORTION OF THE CONTACT AGENT A LONGER TIME THAN AT THE INITIAL SPACE VELOCITY, OXIDATIVELY REGENERATING THE CONTACT AGENT TO RESTORE IT SUBSTANTIALLY TO ITS ORIGINAL FORM AND AGAIN PLACING THE SYSTEM ON-STREAM BY INTRODUCING HYDROGEN CONTAINING GAS AND PETROLEUM HYDROCARBON INTO THE CHAMBER.

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