Two-phase hydrocarbon conversion system

United States Patent Office

3,663,431

Patented May 16, 1972

3,663,431 TWO-PHASE HYDROCARBON CONVERSION SYSTEM Robert E. Wagner, Fullerton, Calif., assignor to Union Oil Company of California, Los Angeles, Calif. No Drawing. Filed Oct. 15, 1969, Ser. No. 866,764 Int. Cl. ClOg 23/02 U.S. Cl. 208—143 21 Claims

ABSTRACT OF THE DISCLOSURE

Hydrocarbons are hydrocracked, hydrofined, hydrogenated and/or demetallized by intimate contacting at elevated temperatures in the presence of hydrogen with an aqueous dispersion of a sulfide of molybdenum, vanadium and/or rhenium. The catalytically active components are conveniently produced in the aqueous phase by reduction and/or sulfurization of the corresponding water soluble sulfides, oxides, acids or salts. These methods are particularly attractive for the selective demetallization and molecular weight reduction and/or removal of asphaltenes and resins.

Heavy hydrocarbons such as raw crude oils and the semirefined heavier hydrocarbon fractions such as heavy distillates, atmospheric residua, vacuum tower bottoms and particularly raw topped crudes are known to contain numerous components which limit their immediate utility and inhibit the effectiveness of hydrocarbon conversion processes intended to convert such fractions to more valuable products. For example, these heavier hydrocarbon fractions are known to contain nitrogenous and sulfur containing compounds as well as organo-metallic compounds, e.g., porphyrins, and high molecular weight carbonaceous coke precursors such as asphaltenes, resins and petroporphyrin hydrocarbons. The more common metallic contaminants are iron, nickel and vanadium, generally existing in concentrations above 50 p.p.m. These contaminants may be present in any one or more of several forms such as the oxides or sulfides, introduced into the crude oil as metallic scale or particles; as the soluble metallic salts; or as organo-metallic components such as the metal porphyrins and metal containing asphaltenes.

The metallic contaminants existing as insoluble oxides, sulfides, etc., may be easily removed, at least in part, by relatively simple filtration and the like. The water soluble salts of these metals are readily removed, at least in part, by water washing and dehydration. However, much more severe treatment is necessary to effect the destruction and/or removal of the organo-metallic impurities, particularly to the degree necessary to produce a crude oil or heavy hydrocarbon fraction suitable for further processing.

Heavy hydrocarbon fractions are also known to contain far greater concentrations of organically bound sulfur and nitrogen compounds than are generally found in lighter hydrocarbons such as the gasoline and light gas oil range hydrocarbons. For example, an untopped Wyoming sour crude having an API gravity of 23.2° at 60° F., contains about 2.8 wt. percent sulfur and about 2700 p.p.m. nitrogen. The nitrogenous and sulfurous compounds are readily converted upon being subjected to catalytic hydrofining, to hydrocarbons, ammonia and hydrogen sulfide. Oxygenated hydrocarbons, if any are present, are usually readily converted to water and the corresponding hydrocarbon counterpart by similar hydrofining procedures. However, the removal or conversion of the catalyst-fouling organo-metallic contaminants or the coke precursors such as asphaltenes and petroporphyrins is not a simple matter and continues to be the subject of extensive investigation.

The asphaltenes, generally characterized as being insoluble in n-pentane, have molecular weights which vary over a considerable range. Analysis of these constituents has illustrated that the molecular weight range is approximately delineated by the limits of 1000 to about 30,000 average molecular weight. The resin fraction of a residual feed is defined as that material which is soluble in npentane but insoluble in n-propane. These resin fractions are known to consist of petroporphyrin molecules generally having molecular weights somewhat below those of the asphaltenes. The combined resin and asphaltene fractions account for the major amounts of metal contaminants in most crude stocks.

Nothwithstanding that the total concentration of metallic contaminants in the asphaltene and resin fractions may be relatively small, for example, less than about 10 p.p.m. calculated as the elemental metals, subsequent processing techniques necessary to convert the heavy hydrocarbon stocks to valuable products are adversely affected thereby. For example, when a hydrocarbon charge stock containing metals in excess of about 3 p.p.m. is subjected to catalytic cracking to produce lower boiling constituents, the metals accumulate upon the catalyst in ever increasing amounts. The ultimate result is modification of the chemical composition and/or structure of the catalyst to an extent that inhibits its activity beyond economic limits. In some instances catalyst selectivity is so modified by the varying metals content that the product distribution obtained deviates considerably from that desired. This particular effect is, of course, highly undesirable not only in catalytic cracking processes but in related processes such as hydrocracking, hydrofining, hydrogenation and the like. The necessary consequence of these events is a diminution in the quantity of valuable products produced and a concurrent increase in production of hydrogen and coke. The coke thus produced further contributes to rapid catalyst deactivation.

In addition to the nitrogen, sulfur and metallic impurities above referred to, heavy raw hydrocarbon stocks also contain substantial amounts of pentane-insoluble asphaltenes and resins. For example, the aforementioned Wyoming sour crude contains 8.3 wt. percent pentaneinsoluble asphaltenes. These constituents are known to be converted to low molecular weight hydrocarbons only with considerable difficulty and, in most instances are converted to coke. The direct consequence of that occurrence is rapid catalyst deactivation and irreversible loss of feed by conversion to coke, hydrogen and less valuable light hydrocarbon gases. These coke precursors exhibit the tendency to deposit almost immediately within the reaction zone and onto the catalyst in the form of high molecular weight gummy residues. The prevention of coke formation and consequent catalyst deactivation as well as the commensurate conservation of feedstock and desired product are obviously desirable objectives.

Several systems directed to the solution of one or more of these problems are discussed by the prior art. One approach involves the emulsification of powdered sulfides of Group VI and VUI metals in the hydrocarbon phase to be converted, followed by contacting with hydrogen at elevated temperatures and pressures as discussed in U.S. Patent No. 1,932,673. As illustrated by the examples hereinafter discussed many of these metal compounds are at best only nominally effective for accomplishing the described objectives. I have also discovered that marked improvement in conversion levels and catalyst life are achieved by dispersing the active components or active component precursors, not in the hydrocarbon phase but

3,663,431 in an aqueous phase maintained in intimate contact with the reactant hydrocarbon phase throughout the conversion period.

An alternative procedure discussed in U.S. Patent No. 3,173,860 involves the dispersion of an oil soluble organometallic compound such as molybdenum hexacarbonyl in the hydrocarbon feed followed by decomposition of the organo-metallic compound to an active species of the metal in the absence of hydrogen. Still another approach discussed in U.S. Patent No. 3,169,919 involves the preliminary formation of a solution of a compound of the active metal in alcohol or water, intimately admixing the solution with a hydrocarbon feedstock and evaporating the solvent prior to conversion. By this procedure, the active metal compound dissolved in the original solution is presumably dispersed throughout the hydrocarbon.phase in its original form without modification. Conversion is conducted in a single phase system in the absence of any liquid phase other than the hydrocarbon feed.

As illustrated by the examples hereinafter discussed, I have discovered that a remarkable improvement in overall conversion level, catalyst life and selectivity toward asphaltenes and resinous hydrocarbons can be achieved by the observance of conditions suitable to maintain an aqueous phase containing the active component precursor in intimate contact with the hydrocarbon feed during the conversion step.

It is therefore one object of this invention to provide an improved hydrocarbon conversion process. It is another object of this invention to provide a method for demetallizing hydrocarbon stocks. It is yet another object of this invention to provide a method for reducing the asphaltene content of heavy hydrocarbon fractions. It is another object of this invention to provide a method for converting n-pentane insoluble asphaltene hydrocarbons to lower boiling constituents. It is another object of this invention to provide a method for hydrogenating hydrocarbons. Yet another object of this invention is the provision of a method for hydrotreating hydrocarbons. It is yet another object of this invention to provide an improved process for the simultaneous denitrogenation, desulfurization and demetallization of heavy hydrocarbon feeds. It is yet another object of this invention to provide an improved method for the conversion of n-pentane insoluble asphaltenic hydrocarbons contained in admixture with lighter hydrocarbons constituents. It is yet another object of this invention to provide an improved method for simultaneously hydrocracking, hydrogenating and demetallizing asphaltenic hydrocarbons. Yet another object of this invention is the provision of an improved method for contacting hydrocarbon conversion catalysts with hydrocarbon feedstocks. It is yet another object of this invention to provide an emulsion process involving at least two liquid phases for the conversion of hydrocarbon feeds.

In accordance with one embodiment of this invention a hydrocarbon feed is converted by contacting with an aqueous colloidal dispersion of a catalytically active amount of at least one disulfide of molybdenum, vanadium and rhenium at a temperature and hydrogen partial pressure sufficient to promote the denitrogenation, desulfurization, hydrogenation, demetallization or hydrocracking of the hydrocarbon feed at a pressure sufficient to maintain a substantial proportion of the water present as liquid phase at reaction conditions.

In accordance with another embodiment of this invention, hydrocarbon feeds usually comprising hydrocarbons boiling above about 400° F., generally above about 600° F., are contacted at reaction conditions of temperature and hydrogen partial pressure with an aqueous system which forms on mixing at least one active metal compound selected from ammonium, sodium and potassium thiomolybdates, dithiomolybdates, thiovanadates, thiorhenates, dithiorhenates and molybdenum trisulfide at a hydrogen partial pressure and temperature sufficient to re4 duce the metal compound to the corresponding sulfide.

In accordance with another embodiment of this invention the aqueous system comprising the active metal sulfide can be formed in situ by sulfiding a compound preferably a soluble compound of the active metal such as the salts, acids and oxides. In this embodiment, the hydrocarbon feed is contacted at reaction conditions of temperature and hydrogen partial pressure with the aqueous system that forms on mixing one or more of ammonium, sodium and potassium molybdates, vanadates and rhenates, molybdic acid and molybdenum blue with water and a sulfur donor, i.e., hydrogen sulfide or carbon disulfide at conditions sufficient to convert the metal salt, acid or oxide to the corresponding sulfide.

I have discovered, as illustrated by the examples hereinafter discussed, that the systems herein described are highly effective for hydrogenating hydrocarbons and are particularly attractive systems for the hydrogenation of aromatic hydrocarbons. These systems also demonstrate marked superiority for the conversion of n-pentane insoluble asphaltenic hydrocarbons contained in heavy hydrocarbon feedstocks to lower boiling constituents when compared to alternative systems. A further advantage derives from the substantial selectivity exhibited for the conversion of asphaltenic hydrocarbons when treated in admixture with lower boiling hydrocarbons.

The specific nature of the conversion which takes place during contacting of a hydrocarbon feedstock with the aqueous systems herein described depends primarily upon the composition of the feedstock, reaction temperature, and hydrogen partial pressure. For example, if the selected feed contains substantial amounts of organometallic compounds such as the petroporphyrins and asphaltenes, demetallization will result to a significant degree. At the same time the molecular weight of the asphaltenes will be considerably reduced due to mild hydrocracking and/or demetallization accompanied by mild hydrogenation when hydrogen partial pressures are sufficiently high. As illustrated by the exemplary operations discussed hereinafter, asphaltenic hydrocarbons are demetallized and hydrogenated at the same time molecular weight is reduced. On the other hand the operating conditions can be selected such that the hydrocarbons, particularly aromatic hydrocarbons, boiling below the petroporphyrins and asphaltenes are only partially or mildly hydrogenated at the conditions of temperature pressure and hydrogen partial pressure found most favorable for the demetallization and molecular weight reduction of the higher boiling asphaltenic hydrocarbons. However, by the use of temperatures toward the upper extremities of the ranges discussed, preferably in combination with higher hydrogen partial pressures, a significant degree of hydrogenation and hydrocracking of lower boiling hydrocarbons can be realized if desired. Nevertheless, the promotion of significant hydrocracking of the lower boiling hydrocarbons is not preferred for several reasons. The degree of cracking and product distribution are usually more expeditiously controlled by the conditions of downstream catalytic cracking and/or hydrocracking systems. The temperatures required to achieve substantial degrees of hydrocracking in the water-hydrocarbon systems of this invention necessitate the use of exceedingly high pressures to maintain a liquid aqueous phase and promote carbonaceous deposit formation on the catalyst. However, a significant degree of hydrogenation can be effected at somewhat milder, more tolerable conditions as demonstrated in the examples.

The methods and compositions of this invention are particularly attractive for the treatment of hydrocarbon mixtures containing substantial amounts of heavy hydrocarbons, particularly asphaltenes and petroporphyrins. A substantial portion, i.e., at least about 5 wt. percent of such hydrocarbon mixtures, e.g., raw crude, topped crude, vacuum bottoms, etc., generally boil above about 1000° F. The application of these systems to the treatment of

3,663.

such hydrocarbon feeds containing at least about 5 wt. percent, and usually from about 10 to about 30 wt. percent of n-pentane insoluble asphaltenes is particularly advantageous. Such feeds also generally contain substantial amounts of metals in the form of organo-metallic 5 compounds of iron, vanadium and nickel. The concentration of these metals expressed as the prevailing amount of the elemental metal is usually within the range of about 5 to about 500 p.p.m. The organically bound nitrogen and sulfur contents of these hydrocarbon mixtures expressed 10 as the equivalent concentrations of elemental nitrogen and sulfur generally exceed 0.1 and 0.3 wt. percent, respectively. The equivalent elemental nitrogen concentrations are generally within the range of 0.2 to about 2.0 wt. percent, while elemental sulfur concentrations are usually 15 within the range of 0.5 to about 5.0 wt. percent.

As previously noted, the systems herein described are also highly effective for the hydrogenation of hydrocarbons, particularly aromatic hydrocarbons having one or more aromatic nuclei per molecule. Since the conversion and regeneration systems made possible by these discoveries are relatively immune to the detrimental effects of carbonaceous deposit formation of the catalyst during reaction, the systems are particularly attractive for the hydrogenation of relatively high molecular weight aromatic compounds. Representative feedstocks are those boiling above about 700° F., usually from about 700° to about 1000+° F. and containing at least about 10 and generally from 40 to about 90 volume percent of aromatic compounds. The connotation of “aromatic compounds” 30 in this sense is intended to include hydrocarbon substituted aromatic nuclei.

The reaction systems herein employed should comprise sufficient liquid water at reaction conditions to provide a relatively high interfacial area between the hydrocar- 35 bon and aqueous phase with sufficient agitation. As the relative water concentration is reduced below a certain minimum, all forms of conversion are reduced accordingly. It is reasonably certain that this effect is attributable to a corresponding reduction in interfacial area between the hydrocarbon and aqueous phases. However, the basic reason for the marked superiority of the two liquid phase system as opposed to a single hydrocarbon phase system is not completely understood. It seems reasonable to conclude, however, that the more lyophilic or surface active constituents in the hydrocarbon feed, particularly ⁰the metal containing asphaltenic and petroporphyrin constituents may tend to concentrate preferentially at the water-hydrocarbon interface, thereby providing more immediate access of these constituents to the active metal ₀θ catalyst. Whatever the reason may be it is presently preferred that the H₂O/hydrocarbon volume ratio be at least about 0.5 and preferably within the range of 1.0 to about 10.

I have also observed that the concentration of the ac- 55 tive metal sulfide in the reaction system has a considerable effect on the several conversions desired. This influence is illustrated by the exemplary operations discussed hereinafter. As a result of this influence it is presently preferred that the weight ratio of the active metal sulfide or metal sulfides to hydrocarbon phase be at least about 0.01 and preferably within the range of from about 0.04 to about 0.50. Active metal concentrations above the upper extremity of this range can, of course, be employed. The use of such high concentrations is not generally economically justified since the desired conversions are adequately realized by catalyst concentrations within the prescribed ranges. In similar manner the H₂O/hydrocarbon volume ratio can also exceed the upper extremity of the preferred range noted for that parameter without detracting from the quality of the hydrocarbon conversions achieved. On the contrary, more rapid conversions are generally attained at higher H₂O/hydrocarbon volume ratios. However, there comes a point at which further increases in this ratio requires such extensive volumes to enable the con431 version of a given volume of hydrocarbon feedstock that a reasonable balance between hydrocarbon conversion, demetallization rates, etc., and reactor volume must be recognized.

Yet another factor worthy of consideration in the hydrocarbon conversion step is the pH of the aqueous phase. The thio salts of the active metals, e.g., thiovanadates, dithiomolybdates, etc., are believed to be unstable at the preferred higher concentrations when the pH of the aqueous phase falls substantially below 7. As a consequence the most desirable results are obtained when the pH of the aqueous phase is above 7, preferably within the range of about 9 to about 11. These neutral or slightly alkaline systems are also easier to handle than are the more acidic systems requiring the use of 'acid resistant materials.

The aqueous phase with which the above described hydrocarbons are contacted comprises a colloidal dispersion or solution of a catalytic amount of the sulfides and/ or thiosalts of one or more of molybdenum, vanadium 20 and rhenium. In most applications, the molybdenum compounds are the most active and are presently preferred. The initial active metal compound concentration in the aqueous phase can vary substantially over a broad range. However, it is presently preferred that the active component concentration not be so high as to result in the agglomeration of the active components in either the aqueous phase or at the water-hydrocarbon interface. It is therefore presently preferred that the concentration the active metal component not exceed the solubility limit at operating conditions. For example, the solubility limit of ammonia thiomolybdate at 25° C. is equivalent to about 3 wt. percent MoS₂. This limit is of course increased substantially at higher temperatures.

The aqueous phase is prepared by admixing either a thermally decomposable sulfur containing compound of the selected active metal with the aqueous phase followed by thermal conversion under pressure sufficient to maintain a liquid aqueous system. The most preferred compounds are the water-soluble salts, acids, and oxides of molybdenum, vanadium and rhenium, particularly the ammonium, sodium and potassium thiomolybdates, dithiomolybdates, thiovandates, thiorhenates, dithiorhenates and molybdenum trisulfide. The aqueous phase containing one or more of these constituents is activated by contacting either in the presence or absence of a hydrocarbon phase, at a temperature of at least about 400° F. and a hydrogen partial pressure of at least about 200 p.s.i. The temperatures employed must of course be below the critical temperature of water, i.e.· 705° F. and are preferably within the range of from about 600 to about 700° F. Presently preferred hydrogen partial pressures are within a range of 500 to about 3000 p.s.i. The total pressure of the system is of course that required to maintain the aqueous phase of the desired proportion in relation to the hydrocarbon phase. As a general rule the total pressure on the system will be at least about 2000 p.s.i.g. preferably from 2500 to about 5000 p.s.i.g.

A high degree of agitation should be maintained throughout the catalyst preparation and hydrocarbon con60 version steps. Such agitation accomplishes at least two essential functions; the dispersion of the active metal components in the aqueous and hydrocarbon phases and the maintenance of a relative high surface are between the liquid phases of the water/hydrocarbon emulsion.

The more complete emulsification which results from higher severe agitation provides the further advantage that equilibrium system vapor pressures at any given temperature are substantially lower than those observed with lower degrees of emulsification. Variation in system pres70 sures of as much as 300 to 400 p.s.i. at the 2500 p.s.i.g. level have been attributed to varying degrees of emulsification.

In the alternative, the active metal sulfides can be prepared by sulfiding a selected compound of the desired ac75 tive metal in the aqueous phase either in the presence or

3,663,431 absence of the hydrocarbon phase. The use of soluble starting compounds of molybdenum, vanadium or rhenium is preferred for the same reasons discussed above. The formation of a colloidal dispersion of the resulting active metal sulfide can be achieved much more easily when the starting materials are completely dissolved in the aqueous phase prior to conversion to the corresponding metal sulfide. Presently preferred compounds are the ammonium, sodium and potassium molybdates, vanadates and rhenates, molybdic acid, molybdenum trioxide and molybdenum blue. One or more of these constituents can be sulfided in situ in the aqueous phase by contacting with a sulfur donor such as hydrogen sulfide, carbon disulfide and the like, at concentrations and temperatures sufficient to convert to the corresponding metal sulfides. The use of hydrogen sulfide at partial pressures of at least about 50 p.s.i. and preferably from 100 to about 1000 p.s.i. is presently preferred for this purpose. The higher pressures promote more rapid conversion to the desired active metal compound.

As previously indicated the effectiveness of these systems is attributable at least in part to the ability of the active metal components to migrate to and possibly through the water hydrocarbon interface into contact with the hydrocarbon feed. The mobility of the active metal compounds can be improved by the addition of a surface active agent, preferably one that is mutually soluble in both the hydrocarbon and aqueous phases. The function of such additives is to reduce the interfacial tension between the water and hydrocarbon phases thereby improving the mass transfer between the two phases. Any compound or additive which will accomplish this purpose without interfering with the essential chemical and physical mechanisms can be employed for this purpose. However, the compounds presently preferred are the lower molecular weight alcohols preferably the mono- or dihydric alcohols having from about 2 to about 6 carbon atoms per molecule. Some advantage can be realized by the addition of small amounts of these additives, e.g., as little as about 0.05 volume percent based on the aqueous phase. However, it is presently preferred that the surface active agent concentration be within the range of about 0.1 to about 1 volume percent.

Although the desired colloidal dispersion of the active metal sulfide can be obtained by reduction of a sulfurcontaining compound of the active metal or in situ sulfidation of the active metal in the presence or absence of the hydrocarbon feed, it is presently preferred that the active sulfides be prepared in colloidal dispersion in the presence of the hydrocarbon phase at reaction conditions. This procedure is not only simpler in that it minimizes the number of steps required but it is also believed to enable the most desirable results with regard to demetallization, hydrogenation, and the like. The most effective systems are presently considered those formed by reduction of the highly water-soluble sulfur-containing compounds of molybdenum, particularly the ammonium thiomolybdates and dithiomolybdates. Of these alternatives, ammonium thiomolybdate is the most desirable due to its relatively high-solubility in water and the ease of converting the dissolved ammonium thiomolybdate to the corresponding sulfide.

The degree of conversion achieved with any of these systems will of course depend in a large part on the duration of contacting of the feed hydrocarbon with the aqueous system at reaction conditions. Some degree of conversion, i.e., molecular weight reduction of asphaltenic hydrocarbons, demetallization, etc., is realized within nominal contact times. However, reaction times of at least about 5 minutes, preferably at least about 10 minutes and generally about 20 minutes to about five hours are usually employed.

A further attractive aspect of the systems herein described is the relative ease with which a catalyst can be recovered and regenerated. During contacting of the water-hydrocarbon reaction phase the active metal compounds enter the hydrocarbon phase generally in the form of insoluble colloidal particles. When the desired degree of conversion has been achieved, the hydrocarbon and aqueous phases can be separated by any one of the many methods known to be effective for separating water and hydrocarbons. Exemplary of such procedures are settling, decantation, fractionation, centrifuging and the like. The insoluble active constituents retained in the hydrocarbon phase can be easily separated therefrom, preferably by physical means, such as filtration, centrifuging, distillation and the like.

The thus recovered catalyst particles generally contain a minor proportion of carbonaceous matter which accumulates on the catalyst during reaction. Therefore the preliminary steps in the catalyst regeneration usually involve treatments effective for the removal of such carbonaceous deposits from the catalyst. This can be conveniently accomplished by washing the recovered catalyst over a filter with a hydrocarbon solvent, preferably an aromatic solvent such as benzene, toluene and the like, followed by calcination of the partially purified catalyst in an oxygen-containing atmosphere at temperatures sufficient to burn off remaining carbonaceous deposits and convert the active metal sulfide to the corresponding oxide. Temperatures required to accomplish this purpose are usually in excess of 800° F., preferably from 1000° to about 1500° F. Elimination of sufficient hydrocarbon from the catalyst by this procedure can usually be accomplished in as little as about 30 minutes. The oxide thus recovered is then converted chemically to the desired starting material. For example ammonium thiomolybdate is conveniently prepared from the calcined oxide by dissolving the oxide in ammonium hydroxide, preferably 7 to about 15 normal ammonium hydroxide, followed by contacting with a sulfur donor such as carbon disulfide, hydrogen sulfide and the like.

The several aspects of this invention are demonstrated by the following examples which are intended only to be illustrative and not limiting of the concepts evidenced thereby.

The feed employed in Examples 1 through 7 and 9 was a 50/50 weight blend of vacuum bottoms and straight run gas-oil having the following characteristics:

Boiling point Weight range,⁰ F. percent

API gravity................ 15.7°......................................

Asphaltenes..______________9.4wt. percent.... 412-70036.3

Metals (V, Fe, Ni).......... 209 p.p.m......... 700-94526.2

Nitrogen................... 0.668 wt. percent.. 94535.8

Sulfur______________________ 2.66 wt. percent... (¹)1.7

Carbon/hydrogen, wt_______7.45.......................................

¹ Loss (overhead).

The metals content (vanadium, iron and nickel) of the hydrocarbon feeds and products employed in each of these examples was determined by emission spectroscopy. Asphaltenes content of the hydrocarbons, feeds and product was determined by precipitation with n-pentane. The sulfur contents of the hydrocarbon mixtures were determined by ASTM D-129 and by X-ray fluorescence. Nitrogen contents were determined by the Kjeldahl method.

Example I

A solution of 100 ml. of water containing 4.85 grams of ammonium thiomolybdate was added to 67.4 grams of

3,663,431 feed in a 0.5 liter dasher-type autoclave. The reactor was then pressured to 34 atm. (500 p.s.i.) with hydrogen and maintained at 660° F. for one hour with severe agitation. The total pressure of the system was about 3100 p.s.i.g. throughout this operation and the hydrogen partial pressure was about 1300 p.s.i. At these conditions a liquid water phase of about 117 milliliters was maintained throughout the operation corresponding to a H₂O/hydrocarbon volume ratio of 1.3. The contents of the reactor were then cooled and filtered. The filtration separated the catalyst solids and broke the product-water emulsion. The hydrocarbon product was then analyzed for sulfur, nitrogen, asphaltenes and metals (vanadium, iron and nickel). The results of these analyses are summarized in Table 1.

These results demonstrate that the asphaltene content was reduced by more than 50 percent, that the total metals content was drastically reduced and that the catalyst was effective in partially hydrofining the hydrocarbon feed.

The product from Example I had the following boiling point range: 422-710° F., 38.5 weight-percent, 710-961° F., 26.2 weight-percent, bottoms product 31.8 weight-percent, loss (overhead) 3.5 weight-percent. Comparison of the boiling point ranges for the feed and product demonstrates that substantial conversion of asphaltenes can be achieved without significantly affecting the boiling point range of the remainder of the hydrocarbon mixture if that result is most desired.

Example II

The conditions of Example I were repeated to enable a more comprehensive evaluation of the nature of asphaltenes conversion. The carbon/hydrogen weight ratio, nitrogen, sulfur and metals contents of both the feed and product asphaltenes were determined and are compared in the following table.

The asphaltenes were isolated from the feed hydrocarbon and product of this example by contacting one volume of the hydrocarbon phase with 7.3 volumes of n-pentane at a temperature of 75° F. and recovering the insoluble asphaltenes after standing for one day. After filtering, the asphaltene residue was washed free of oil with n-pentane. The following comparative analyses were obtained:

containing 100 ml. water and 1.62 grams of ammonium thiomolybdate was also charged to the autoclave. The reactor was pressured to 43.5 atm. with hydrogen and then maintained at 660° F, for one hour.

After cooling, the contents of the reactor were removed. The water and hydrocarbon formed separate phases. To insure complete recovery of the hydrocarbon product it was dissolved in benzene and the reactor assembly was washed with benzene. The benzene solution of the hydro10 carbon product was filtered to remove catalyst solids and then distilled to remove the benzene.

The hydrocarbon product showed a substantial improvement in properties. It contained only 0.13 percent asphaltenes, 0.237 percent nitrogen and 1.07 percent sul15 fur and exhibited a markedly increased gravity of 22.3° API. The marked effectiveness of the higher H₂O/hydrocarbon weight ratio for asphaltenes conversion and hydrofining is readily apparent.

The amount of feed added to this example was not 20 large enough to produce an amount of product sufficient to enable the complete evaluation of the product with regard to metals content. Therefore this operation was repeated to provide additional product so that those evaluations could be made. That operation is reported as Ex25 ample 4.

Example IV

Thirteen grams of feed were charged to a 0.5 liter dasher-type autoclave. A solution of 100 ml. of water ³⁰ containing 1.82 grams of ammonium thiomolybdate was also charged to the autoclave. The reactor was pressured to 43.5 atm. with hydrogen and then maintained at 660° F. for one hour. The total pressure on the system during this operation was about 3200 p.s.i.g., sufficient to main³³ tain about 112 ml. of water as the liquid aqueous phase. The calculated H₂0/hydrocarbon volume ratio in the liquid phase was 6.2.

After cooling, the hydrocarbon product was recovered in the same manner as in Example II. The total metals ^υ content of the product was 7.0 p.p.m. (vanadium, nickel and iron) calculated as the elements. Asphaltenes content of the product was 0.71 weight-percent.

Example V

Feed Product asphaltenes asphaltenes

Metals, p.p.m.: V________________________

Ni.......................

Fe.......................

Carbon, wt. percent.........

Hydrogen, wt. percent______

C/H ratio___________________

Nitrogen (total) wt. percent. Sulfur, wt. percent__________

These results illustrate the existence of little variation between the composition of the feed and product asphaltenes after more than 50% asphaltene conversion indicating that all species of asphaltenes were converted at -₀similar rates.

Example III

Thirteen grams of the hydrocarbon feed were charged to a 0.5 liter dasher-type autoclave. An aqueous solution 75

This example was run at such a low initial water hydrocarbon volume ratio that no liquid water phase was present after heatup to reaction conditions. Sixty-seven grams of the hydrocarbon feed, 25 ml. of water and 4.85 grams of ammonium thiomolybdate were charged to a 0.5 liter dasher-type autoclave. The autoclave was then pressured to 640 p.s.i.g. with hydrogen. The contents Were contacted for one hour at 660° F. under a hydrogen partial pressure of about 1500 p.s.i. Severe agitation was maintained throughout the run. The product was recovered and analyzed as described in Example I. Results of the product analyses are reported in Table 1.

From these results it is readily apparent that only nominal conversion of asphaltenes was effected in the absence of a liquid water phase. The API gravity of the product differed from that of the feed by only an insignificant amount and the nitrogen and sulfur contents and carbon/hydrogen ratio were not changed at all. Similarly, the reduction in metals content in this example was nowhere near comparable to that achieved in the systems containing a liquid water phase at reaction conditions.

Example VI

This example further illustrates the effectiveness of the described systems for asphaltene conversion, hydrofining and demetallization. Fourteen and sixteen grams of the hydrocarbon feed, 100 ml. of water and 1.82 grams of ammonium thiomolybdate were admixed in a 0.5 liter

3,663,431 ¹¹ dasher-type autoclave to provide a reaction mixture having a catalyst/hydrocarbon weight ratio of 0.0766 and a water/hydrocarbon volume ratio of about 6.2 at reaction conditions. This system was contacted for one hour at 660° F. under a hydrogen partial pressure of about 1600 p.s.i. and a total system pressure at reaction conditions of 3100-3200 p.s.i.g. The product was filtered, recovered and analyzed as previously described and contained only 0.32 weight-percent asphaltenes, 6 p.p.m. metals, 0.517 weightpercent nitrogen, 1.54 weight-percent sulfur. The carbon/ hydrogen weight ratio of the total product was 7.04 as compared to 7.45 for the total feed.

Example VII

This example is similar to Example I with the exception that ammonium dithiomolybdate (ΝΗ^ΜοΟ^ was substituted for ammonium thiomolybdate. Sixty-eight grams of the hydrocarbon feed, 100 ml. of water and 4.26 grams of ammonium dithiomolybdate were added to a 0.5 liter dasher-type autoclave to provide a catalyst/ hydrocarbon weight ratio of 0.0440 based on MoS₂. This system was contacted for one hour at a temperature of 660° F. under a hydrogen partial pressure of about 1800 p.s.i. a total system pressure at reaction conditions of 2600 p.s.i.g. sufficient to maintain an aqueous liquid phase of 148 ml. The hydrocarbon product was filtered, recovered and analyzed as previously described. The analyses showed that the metals content had been reduced from the original 209 p.p.m. to 130 p.p.m. while the asphaltenes content had been reduced to 5.6 weight-percent. Nitrogen and sulfur contents of the product were 0.58 and 2.40 weight-percent respectively. It is apparent that the conversion system of this example was effective in reducing the metals, asphaltenes, nitrogen and sulfur contents of the hydrocarbon feed although it was not as effective as systems employing ammonium thiomolybdate at otherwise similar conditions.

Example VIII

This example demonstrates the effectiveness of the systems of this invention in the hydrogenation of hydrocarbons, particularly aromatic hydrocarbons. The feed employed in this example was 1-methylnaphthalene containing 0.147 weight percent nitrogen and 0.98 weight percent sulfure and having an API gravity of 7.3. Fifty •milliliters of this hydrocarbon feed, 100 ml. of water and 3.25 grams of ammonium thiomolybdate were contacted with rapid agitation for two hours at 660° F. at a hydrogen partial pressure of about 1600 p.s.i. under a total system pressure at reaction conditions of 3100 p.s.i.g. sufficient to maintain an aqueous liquid phase of about 123 ml. The oil product was separated from the aqueous phase and solid catalyst in a separatory funnel, washed with 0.33 volumes of 1 N sodium hydroxide per volume of hydrocarbon followed by two washings with 0.33 volume of fresh water per volume of hydrocarbon. The resultant product was dried over calcium chloride and then filtered before being analyzed for nitrogen, sulfur, API gravity and hydrocarbon composition. The nitrogen and sulfur contents of the product had been reduced to 0.103 to 0.337 weight percent respectively illustrating substantial hydrofining activity. The API gravity had increased from 7.3° to 10.2°. Analysis of the product by mass spectrometry confirmed the presence of 21 volume percent of Cn-methyltetralins.

i Example IX

In order to distinguish between the chemical effects of the catalyst heretofore described and the possible influence of physical effects associated with the presence of a solid media in the hydrocarbon-aqueous system, an operation similar to the foregoing examples was repeated using inert solids rather than an active catalyst. In this example, 14.3 g. of the hydrocarbon feed, 100 ml. of water and 1.62 g. of “inert” particulate calcined alumina were added to the 0.5 liter dasher-type autoclave. In order to more closely assimilate the chemical characteristics of the active catalyst containing systems—at least with regard to the aspects of those systems which would influence the removal of asphaltenes from the hydrocarbon phase—the water phase added to the autoclave was saturated with hydrogen sulfide and combined with 0.77 ml. of concentrated ammonia. The autoclave was then pressured with hydrogen to 640 p.s.i.g. at ambient conditions (75° F.) and heated to 660° F. with thorough agitation for 1 hour under a total system pressure of 3200 p.s.i.g. The reaction phase was recovered and analyzed as previously described in Examples II and III. The results of those analyses are reported in the table.

Example X

In order to illustrate the effectiveness of the described systems for demetallizing hydrocarbon mixtures containing metals combined with components other than the asphaltenes, an illustrative operation was conducted on the hydrocarbon feed described in Example I, subsequent to deasphalting. That material was deasphalted by thoroughly contacting the hydrocarbon feed with n-pentane to precipitate the asphaltenic hydrocarbons. The supernatent n-pentane phase was separated from the precipitated asphaltenes and distilled to remove pentane. This material was then reacted in the presence of hydrogen, water and ammonium thiomolybdate in accordance with the procedures described in Example I. The product was recovered and analyzed as described in Examples II and III. The results of these analyses on both the deasphalted feed and the product are presented in the following table:

Deasphalted feed Product

Metals, p.p.m.: Vanadium........... 316

Nickel_______________ 273

Iron_________________ 233

Total______________ 8112

It is apparent from the analyses of the deasphalted feed that a considerable proportion of the metals present in the original feed were abstracted during the pentane deasphalting step. Nevertheless, the feed to this example still contained a total of 81 parts per million of metals, most of which are believed to be combined with the resin fraction of the original feed and therefore, would not be removed by the described pentane treatment. The concentration of all three metals monitored was dramatically reduced so that the total metals content of the final product was only 12 parts per million illustrating the effectiveness of these systems for treating hydrocarbons other than simply asphaltenic feeds.

Example XI i

This example illustrates the relative lack of effectiveness of compounds closely related to the catalysts employed in the methods of this invention. The ammonium thiotungstate employed in this example was not effective in altering the asphaltenes, nitrogen or sulfur contents of the feed hydrocarbon and was only slightly effective in lowering the metals content thereof.

Fifty grams of the hydrocarbon feed, 100 ml. of water and 4.36 grams of ammonium thiotungstate were added to a 0.5 liter dasher-type autoclave and the autoclave was pressured to 43.5 atm. with hydrogen. The admixture was contacted under severe agitation for one hour at 660° F. at a total system pressure of 2800 p.s.i.g. The asphaltenes content of the product was 9.0 weight-percent and the nitrogen and sulfur contents were 0.686 and 2.52 weightpercent respectively illustrating no significant variation

3,663,431 from the composition of the hydrocarbon feed. The metals content, i.e., vanadium, nickel and iron had been reduced from the original value of 209 to 151 p.p.m.

TABLE pressure of at least about 2000 p.s.i.g. for about 20 minutes to about 5 hours.

8. The method of claim 1 wherein said aqueous phase forms on contacting at least one of ammonium, sodium

<td> Example____________________________—</td><td> 1</td><td> 3</td><td> 4</td><td> 5</td><td> 6</td><td> 7</td><td> 9</td><td> 10</td><td> 11</td>

<td> Feed, g...............................</td><td> 67.4</td><td> 13</td><td> 13</td><td> 67</td><td> 14.6</td><td> 68</td><td> 14.3</td><td>¹ 67.7</td><td> 50</td>

<td rowspan="2"> Water feed, ml........................ HjO phase, ml.²......................</td><td> 100</td><td> 100</td><td> 100</td><td> 25</td><td> 100</td><td> 100</td><td> 100</td><td> 100</td><td rowspan="2"> 100</td>

<td> 117</td><td> 112</td><td> 112</td><td> 0</td><td> 112</td><td> 148</td><td> 112</td><td> 148 _</td>

<td> Catalyst, g............................</td><td> 3 4.85</td><td>³1.62</td><td>³1.82</td><td> «4.85</td><td>³ 1.82</td><td> «4.26</td><td> «1.62</td><td> 4.85</td><td>⁶ 4.36</td>

<td> Ha, p.s.i___________________·..... </td><td> 1,300</td><td> 1,650</td><td> 1,650</td><td> 1,500</td><td> 1,600</td><td> 1,800</td><td> 1,600</td><td> 1,800</td><td rowspan="2"> 1,500 660</td>

<td> Temperature,⁰ F.....................</td><td> 660</td><td> 660</td><td> 660</td><td> 660</td><td> 660</td><td> 660</td><td> 660</td><td> 660</td>

<td> Time, hr._____________________________</td><td> 1</td><td> 1</td><td> 1</td><td> 1</td><td> 1</td><td> 1</td><td> 1</td><td> 1</td><td> 1</td>

<td> Total press., p.s.i.g....................</td><td> 3,100</td><td> 3,200</td><td> 3,200 ..</td><td></td><td> 3,100-3,200</td><td rowspan="2"> 2,600</td><td rowspan="2"> 3,200</td><td rowspan="2"> 2,700</td><td rowspan="2"> 2,800</td>

<td> HaO/hydrocarbon volume ratio⁷______</td><td> 1.3 ..</td><td></td><td> 6.2 ..</td><td></td><td rowspan="2"> 6.2 .</td>

<td> Catalyst/hydrocarbon weight ratio...... Product:</td><td></td><td></td><td></td><td></td><td> »0.044 ..</td><td></td><td> —</td><td></td>

<td> Asphaltene, wt. percent___</td><td> 4.2</td><td> 0.13</td><td> 0.76</td><td> 8.4</td><td> 0.32</td><td> 5.6</td><td> 8.4</td><td></td><td> 9.0</td>

<td> Nitrogen, wt. percent.............</td><td> 0.562</td><td> 0.237 ..</td><td></td><td> 0.661</td><td> 0.517</td><td> 0.580</td><td> 0.622</td><td> 0.463</td><td> 0.686</td>

<td> Sulfur, wt. percent________________ API°...............................</td><td> 2.10</td><td> 1.07 .. 22.3 ..</td><td></td><td> 2.69 16.3 .</td><td> 1.54</td><td> 2.40</td><td> 2.38</td><td> 2.39</td><td> 2.52</td>

<td rowspan="2"> Metals, p.p.m..................... Carbon/hydrogen, wt...............</td><td> 36 ..</td><td></td><td> 7</td><td> 122</td><td> &lt;6</td><td rowspan="2"> 130</td><td></td><td> 12</td><td rowspan="2"> 151</td>

<td></td><td></td><td></td><td> 7.45</td><td> 7.04 .</td><td> 7.51</td><td> 7.25 .</td>

¹ Deasphalted feed, 81 p.p.m. metals; 0.502 wt. percent Na; 2.54 wt. percent S.

² Calculated from reactor volume, feed and reaction conditions.

a Ammonium thiomolybdate.

* Ammonium dithiomolybdate.

e Inert solids.

• Ammonium thiotungstate.

⁷ Calculated for reaction conditions.

Based on equivalent M0S2 content.