US3336219A

US3336219A - Hydrorefining of petroleum crude oil with diimino molybdenum chloride and complexes tereof

Info

Publication number: US3336219A
Application number: US421674A
Authority: US
Inventors: William K T Gleim
Original assignee: Universal Oil Products Co
Current assignee: Universal Oil Products Co
Priority date: 1964-12-28
Filing date: 1964-12-28
Publication date: 1967-08-15
Anticipated expiration: 1984-08-15

Description

United States Patent 3,336,219 HYDROREFINING OF PETROLEUM CRUDE OIL WITH DHMINO MOLYBDENUM CHLORIDE AND COMPLEXES THEREOF William K. T. Gleim, Island Lake, 11]., assignor to Universal Oil Products Company, Des Plaines, III., a corporation of Delaware No Drawing. Filed Dec. 28, 1964, Ser. No. 421,674 11 Claims. (Cl. 208-264) The present invention relates to a process for the hydrorefining of heavy hydrocarbon fractions and/or distillates. More specifically, the present invention is directed toward a process for treating, or the decontamination of petroleum crude oils and topped, or reduced crude oils for the primary purpose of removing organo-metallic contaminants, and converting pentane-insoluble asphaltenic material, which process is characterized by the catalyst utilized therein.

Petroleum crude oils, and topped or reduced crude oils, as well as other heavy hydrocarbon fractions and/ or distillates, including black oils, heavy cycle stocks, visbreaker liquid efiluent, crude tower bottoms product, tar sand oils, etc., are contaminated by the inclusion of excessive quantities of various non-metallic and metallic impurities which detrirnentally affect various processes to which such heavy hydrocarbon mixtures may be subjected. Among the non-metallic impurities are nitrogen, sulfur and oxygen which exist as heteroatomic compounds, nitrogen probably being most undesirable because it effectively poisons the various catalytic composites which may be employed in the conversion of petroleum fractions. Both nitrogenous and sulfurous compounds are objectionable because combustion of fuels containing these impurities results in the release of nitrogen oxides and sulfur oxides which are noxious, corrosive, and present therefore a serious problem with respect to atmospheric pollution. With respect to motor fuels, sulfur and sulfurous compounds are particularly objectionable because of odor, gum and varnish formation, and significantly decreased lead susceptibility.

In addition to the foregoing described contaminating influences, petroleum crude oils and other heavy hydrocarbonaeeou-s material contain high molecular weight as-v phaltenic compounds. These are non-distillable, oil-insoluble coke precursors which often :are found to contain sulfur, nitrogen, oxygen and various metals. Of the metallic contaminants, those containing nickel and vanadium are most common although other metals including iron, copper, lead, zinc, etc., are often present. Although the metallic contaminants may exist within the hydrocarbonaceous material in a variety of forms, they are generally present as organo-metallic compounds of relatively high molecular weight, such as metallic porphyrins and the various derivatives thereof. A reduction in the concentration of the organo-metallic complexes is not easily achieved, and to the extent that the crude oil, reduced crude oil, or other heavy hydrocarbon charge stock becomes suitable for further processing. Notwithstanding that the concentration of these organo-metallic complexes may be relatively small in the lighter distillate fraction, for example often less than about p.p.m., calculated as if the complex existed as the element metal, subsequent processing techniques are adversely affected thereby. With respect to a process for hydrorefining or treating of hydrocarbon fractions and/or distillates, the presence of large quantities of asphaltenic material and organo-metallic compounds interferes considerably with the activity 'of the catalyst to effect the destructive removal of the nitrogenous, sulfurous. and oxygenated compounds, which posite to perform to an acceptable degree. It is highly desirable, therefore, to produce :a hydrocarbon mixture substantially free from asphaltenic material and organomet-allic compounds, and which is substantially reduced in nitrogen and sulfur concentration.

The present invention encompasses a method for effecting the hydrorefining of a wide variety of hydrocarbon fractions and/ or distillates. Such heavy hydrocarbon fractions include full boiling range crude oils, topped or reduced crude oils, atmospheric distillates, visbreaker bottoms product, heavy cycle stocks from thermally or catalytically-cracked charge stocks, heavy vacuum gas oils, tar sand oils, etc. Typical of such charge stocks is a Wyoming sour crude oil, having a gravity of 23.2 API at 60 F., and contaminated by the presence of about 2.8% by weight of sulfur, 2,700 p.p.m. of total nitrogen, approximately 100 p.p.m. of metallic complexes, computed as the elemental metals, and consisting of a high boiling, pentane-insoluble asphaltenic fraction in an amount of about 8.4% by weight. A more difficult charge stock, to convert into useful liquid hydrocarbons, is a crude tower bottoms product having a gravity, API at 60 F., of 14.3, and contaminated by the presence of 3.0% by weight of sulfur, 3,830 p.p.m. of: total nitrogen, p.p.m. of total metals and about 10.93% by weight of asphaltenic compounds. Likewise, an atmospheric tower bottoms product, having a gravity of 7 .0 API at 60 F., is contaminated by 6,060 p.p.m. of total nitrogen, 4.05% by weight of sulfur, more than 450 p.p.m. of total metals and contains an asphaltenic fraction in an amount of about 24.0% by weight. As hereinbefore stated, asphaltenic material is a high molecular weight hydrocarbon mixture having the tendency to become immediately deposited within the reaction zone and other process equipment, and onto the catalytic composite in the form of a high molecular weight residue. Furthermore, the presence of excessive quantities of asphaltenes tends to inhibit the activity of the catalyst with respect to the destructive removal of sulfur and nitrogen.

The object of the present invention is to provide a more suitable, effective process for hydrorefining heavy hydrocarbonaceous material, and particularly full boiling range crude oils, and topped or reduced crude oils. An essential feature of the process of the present invention resides in the character of the catalyst utilized to promote the desired reactions. The present invention affords the utilization of either a fixed-bed, or fixed-fluidized hydrorefining process, or a slurry-type process in which the catalyst and charge stock are intimately admixed. Heretofore, the fixedbed hydrorefining process has not been considered feasible due to the excessive deposition of coke and other gummy carbonaceous material within the reaction zone. Although the difficulties encountered in a fixed-bed catalytic process are at least partially solved by a moving-bed or a slurrytype operation, the latter tend to result in a high degree of erosion, thereby causing plant maintenance and replacement of process equipment to be difficult and expensive. These difliculties are in turn partially avoided through the use of a fixed-fluidized process in which the catalytic composite is disposed within a confined reaction zone, being maintained in a fluidized state by exceedingly large quantities of a fast-flowing hydrogen-containing gas stream. The crude oil hydrorefining process of the present invention may be effected in a fixed-bed unit Without incurring the difficulties hereinbefore described. Furthermore, the particular catalytic composite, when unsupported, permits an efficient, economical utilization of the slurrytype process. When combined with a refractory inorganic oxide carrier material of suitable particle size, the catalyst hereinafter described also permits the economic use of a fixed-fluidized bed process. In any event, the process of the present invention, characterized by the catalyst hereinafter described in further detail, is especially advantageous in effecting the removal of organo-metallic compounds while simultaneously converting pentane-insoluble material into pentane-soluble liquid hydrocarbons, and effecting the destructive removal of significantly large quantities of sulfurous and nitrogenous compounds.

Therefore, in a broad embodiment, the present invention encompasses a process for hydrorefining a hydrocarbon charge stock, which process comprises reacting said charge stock with hydrogen in contact with a molybdenum compound selected from the group consisting of diimino molybdenum chloride and a transitional metal complex thereof, and at hydrorefining conditions.

Another embodiment of the present invention involves a process for hydrorefining an asphaltene-containing hydrocarbon charge stock, which process comprises admixing said charge stock with a transitional metal complex of diimino molybdenum chloride having the following structural formula:

and wherein Me is a metal from the group of iron, cobalt, nickel, platinum, palladium, ruthenium, rhodium and manganese; reacting the resulting mixture with hydrogen in the presence of added hydrogen sulfide at hydrorefining conditions and recovering a substantially asphaltene-free hydrorefined liquid product.

A more limited embodiment of the present invention affords a process for hydrorefining a petroleum crude oil containing pentane-insoluble asphaltenes, which process comprises reacting said charge stock with hydrogen in the presence of from 1.0% to 15.0% hydrogen sulfide, at hydrorefining conditions including a temperature of from about 225 C. to about 500 C, and a pressure within the range of about 500 to about 5,000 pounds per square inch, in contact with a catalytic composite of silica and from about 12.0% to about 88.0% by weight of alumina, combined with a molybdenum compound selected from the group consisting of diimino molybdenum chloride and a transitional metal complex thereof having the following structural formula:

The remainder of the group, from which the catalyst is derived, constitutes the transitional metal complexes of the diimino molybdenum chloride. These transitional metal complexes have the following structural formula:

ClMo \N (2) The transitional metals, designated in the foregoing structural formula by Me, are selected from the group consisting of iron, cobalt, nickel, platinum, palladium, ruthenium, rhodium and manganese. When utilized in a slurry-type process, the catalyst, for example, the nickel complex of diimino molybdenum chloride, is admixed with the charge stock in an amount of from about 5.0% to about 30.0% by weight thereof. In order to facilitate the formation of the colloidal suspension or dispersion of the catalytic component within the charge stock, it is preferred to employ the complex as a finely-divided, talc-like powder. The power is added to the petroleum crude oil, or other heavy carbonaceous mixture, as suitable incremental portions of the total amount, accompanied by agitation; in this manner, the colloidally dispersed catalyst is suspended within the charge stock virtually immediately upon the addition thereto.

When effected as a slurry-type process, the hydrorefining of petroleum crude oils may be conducted in a batch-type manner or in an enclosed vessel through which the colloidal suspension is passed; when effected in a continuous manner, the process may be conducted in either upward flow or downward flow. The normally liquid hydrocarbons are separated from the total reaction zone efiluent by any suitable means, for example, through the use of a centrifuge or settling tank, at least a portion of the resulting catalyst-containing sludge being combined with the fresh petroleum crude oil and recycled to the reaction zone. In order to maintain the highest possible degree of activity, it is preferred that at least a portion of the catalyst-containing sludge be removed from the process prior to combining the remainder with fresh crude oil. The precise quantity of the catalyst-containing sludge removed from the process will be dependent upon the desired degree of contaminant removal. It is further desirable to add a quantity of the molybdenum compound to the petroleum crude oil in order to compensate for that quantity removed with the catalyst-containing sludge.

When the present process is conducted in a fixed-bed, or fixed-fluidized manner, the molybdenum compound is combined with a suitable refractory inorganic oxide carrier material. Although the precise composition and method of manufacturing the carrier material is not considered a limiting feature of the present invention, the preferred carrier material, in order to have the most advantageous physical and chemical structure, will contain at least a portion of alumina and have an apparent bulk density less than about 0.35 gram/cc. The preferred catalytic composite comprises a carrier material of silica and from about 12.0% to about 88.0% by weight of alumina. In many instances, however, other refractory inorganic oxides may be employed in conjunction with the alumina, and include zirconia, magnesia, titania, boria, strontia, hafnia, and mixtures of two or more. By way of specific examples, a satisfactory carrier material may comprise equimolar quantities of alumina and silica, or 63.0% by weight of alumina and 37.0% by weight of silica, or a carrier of 68.0% by weight of alumina, 10.0% by weight of silica and 22.0% by weight of boron phosphate. The refractory inorganic oxide carrier material may be formed by any of the numerous techniques which are rather well defined in the prior art. Such techniques include the acidtreating of a natural clay, sand or earth, co-precipitation, or successive precipitation from hydrosols, and which are frequently coupled with one or more activating treatments which include hot oil aging, steaming, drying, oxidizing, reducing, calcining, etc. The pore structure of the carrier material, commonly defined in terms of surface area, pore diameter and pore volume, may be developed to specified limits by any means including aging the hydrosol and/or hydrogel under controlled acidic or basic conditions, or by gelling the carrier at a critical pH or by treating the carrier with various inorganic and/or organic reagents.

.The catalyst is prepared by initially forming an alumina-containing refractory inorganic oxide carrier material having the foregoing described characteristics. For example, an alumina-silica composite containing about 63.0% by 'weight'of alumina is prepared by the co-precipitation of the respective hydrosols. The precipitated material, generally in the form of hydrogel, is dried at a temperature of about 100 C. and for a time sufficiently long to remove substantially all of the physically-held water. The composite is then subjected to a high-temperature calcination technique in an atmosphere of air, for a period of about one hour at a temperature above about 300 C., which technique serves to remove the greater proportion of the chemically-bound water. The calcined carrier material is then impregnated With gaseous molybdenum chloride (MoCl in an inert atmosphere, such as nitrogen. The thus impregnated carrier is then treated with ammonia and calcined in an inert atmosphere at a temperature of about 300 C., to convert the molybdenum chloride to diimino molybdenum chloride. Where it is desired to employ a transitional metal complex of the diimino molybdenum chloride, the ammonia-treated and calcined composite is next impregnated with a salt of the selected transitional metal dissolved in a suitable organic solvent including alcohols, esters, ketones, aromatic hydrocarbons, etc. The transitional metal salt is employed in an amount of one metal atom to two mols of diimino molybdenum chloride, and sufficient to result in a final composite containing about 5.0% to about 30.0% by weight of the transitional metal complex. The impregnated alumina-containin'g composite is dried at a temperature less than about 150 C., and preferably within the range of about 100 C. to about 150 C., and then calcined at a temperature of from 500 C. to 600 C.

The preferred manner of effecting the hydrorefining of heavy hydrocarbonaceous material, in accordance with the process of the present invention, utilizes a fixed-bed of the catalytic composite prepared in accordance with the procedure hereinbefore set forth. The fixed-bed process is effected by initially admixing the hydrocarbon charge stock with hydrogen in an amount within the range of from about 5,000 to about 50,000 s.c.f./b.b.1. of liquid hydrocarbons. It has been found that the end results are enhanced through the utilization of added hydrogen sulfide in an amount within the range of about 1.0% to about 15.0%. The mixture is heated to a temperature of from about 225 C. to about 500 C. and passes into the reaction zone maintained under imposed pressure within the range of about 500 to about 5,000 pounds per square inch. The hydrocarbon charge contacts the fixed-bed of catalyst at a liquid hourly space velocity (defined as volumes of liquid hydrocarbon charge per hour per volume of catalyst disposed within the reaction zone) of from about 0.5 to about 5.0. It is preferred that the reaction zone atmosphere comprise hydrogen sulfide which has been added with the hydrogen-containing gas stream, as distinguished from that which may be produced by the hydrogenation/hydrocracking reaction. That is, the beneficial effects of added hydrogen sulfide appear to occur only when thelatter is present at the time the hydrogenation reactions are being initiated. The precise operating conditions, including temperature and pressure, are at least partially dependent upon the physical and chemical characteristics of the hydrocarbon charge stock, the length of the period during which the catalyst has been functioning, and the desired end result.

The following examples are given for the purpose of illustrating the method by which the process of the present invention is effected, and the benefits afforded the hydrorefining of heavy hydrocarbonaceous material through the utilization therein of a particular catalyst. The charge stocks, temperatures, pressures, catalyst, range, etc., are herein presented as being exemplary only, and are not intended to limit the present invention to an extent greater than that defined by the scope and spirit of the appended claims.

6, Example I The charge stock employed in illustrating the fixed-bed hydrorefining process, utilizing the molybdenum complex catalytic composite, is'a topped Wyoming sour crude oil. The natural crude oil, having a gravity of 232 API at 60 F., is contaminated with 2.8% by weight of sulfur, approximately 2,700 p.p.m. of total nitrogen, 100. p.p.m. of metallic porphyrins (computed as if the metallic component existed as elemental nickel and vanadium), and comprises a high-boiling, pentane-insoluble asphaltenic fraction in an amount of about 8.39% by weight of the total crude oil. The topped crude oil indicates a gravity, API at 60 F., of 19.5, and contains 3.0% by weight of sulfur, about 2,900 p.p.m. of total nitrogen, p.p.m. of nickel and vanadium, the pentane-insoluble asphaltenic fraction being about 8.5% by weight. a

The catalytic composite is a spray-dried alumina-silica carrier material containing about 63.0% by weight of alumina on a dried basis. The spray-dried composite is oxidized or calcined in an atmosphere of air for a period of about one hour at a temperature of about 550 C. The calcined alumina-silica composite, at a temperature below about 265 C., is impregnated with vaporous molybdenum pentachloride in admixture with nitrogen. Without increasing the temperature, the molybdenum pentachloride impregnated composite is treated with ammonia and calcined in nitrogen at a temperature of 300 C., to produce the diimino molybdenum chloride within the composite. An iso-amyl alcohol solution of platinum tetrachloride is used in an impregnating technique to form the platinum complex of diimino molybdenum chloride within the composite, and in an amount such that the final composite, after calcination at a temperature of 550 C., contains about 15.0% by weight of said complex.

The calcined composite, having a particle size ranging from about 20 to about microns, is disposed as a fixed-bed in a reaction zone in an amount of about 200 grams. The temperature of the catalyst is increased to a level of-about 400 C., and hydrogen, containing from about 1.0% to about 15.0% hydrogen sulfide is admixed with the previously described topped Wyoming sour crude oil, in an amount of about 25,000 s.c.f./bbl. of liqnideharge. A compressor is utilized to. maintain thepres- "sure within the reaction zone at about 1,500 pounds per square inch.

The total product effluent from the reaction zone is continuously cooled and passed into a high-pressure separator from which a liquidhydrocarbo'n product is removed to a receiver, the hydrogen-rich gas stream being passed through a scrubber and recycled to the reactor. In order to compensate for that quantity of hydrogen consumed "withinthe process, and absorbed by the normally liquid product efiluent, fresh hydrogen is added to the recycle 'gas stream as determined by the operating pressure within the reaction zone, in this instance being in an amount of about 2,000 s.c.f./bbl. For approximately one-half of its effective, acceptable life, the catalytic composite will promote the necessary hydrogeriation/hydrocracking reactions to produce a normally liquid product which is sub- 's tantially free from pentane-insoluble asphaltenes, organometallic contaminants and sulfurous and nitrogenous compounds. Thus, the normally liquid product eifiuent will contain less than about 0.5% by weight of pentane-insoluble asphaltenes, less than about 0.5 p.p.m. of organometallic compounds, less than 50 p.p.m. of total nitrogen, and less than about 0.10% by Weight of sulfur, the gravity thereof being within the range of about 30.0 to about 32.0 API at 60 F. 1 1

As hereinbefore set forth, the presence of excessive quantities of pentane-insoluble asphaltenes as well as the organo-metallic compounds, interferes considerably with the capability of the catalyst to eifect the destructive removal of nitrogenous and sulfurous compounds. Therefore, the catalyst. will indicate a. normal activity decline through an increase in the concentration of residual sulfurous and nitrogenous compounds in the normally liquid product eflluent. However, since the concentration of pentane-insoluble asphaltenes and organo-metallic compounds will continue to be below 0.5% by weight and 0.5 p.p.m. respectively, the operation may be continued on an economic basis notwithstanding a comparatively high concentration of residual, nitrogenous and sulfurous compounds. In this situation, the normally liquid product effiuent is subjected to a second stage operation at significantly more severe conditions for the purpose of effecting the complete destructive removal of the remaining sulfurous and nitrogenous compounds.

Example II Diimino molybdenum chloride, in an amount of about 20.0 grams, and in the form of talc-like powder, is added to 200 grams of the Wyoming sour crude oil hereinabove described. The resulting mixture is placed in an 850 cc. rocker-type autoclave, pressured to 10 atmospheres with hydrogen sulfide, then to 100 atmospheres with hydrogen, and slowly heated to a temperature of about 400 C., resulting in a final pressure of about 220 atmospheres; these conditions are maintained for a period of about eight hours. The autoclave is permitted to cool, and is simultaneously depressured to atmospheric conditions. The normally liquid product effluent, following separation from the metal-containing sludge, indicates a gravity, API at 60 F., of 32.6. Analyses indicate that the liquid hydrocarbon fraction is contaminated by only 150 p.p.m. of nitrogen, 0.20% by weight of sulfur and only about 0.04% by weight of pentane-insoluble asphaltenes. The analyses further show that the concentration of organometallic porphyrins is less than about 0.5 p.p.m.

The foregoing specification and examples clearly indicate the benefits afforded a process for hydrorefining petroleum crude oil, and other heavy hydrocarbonaceous material, through the utilization of the present invention. The contaminating influences have been removed to the extent required for further processing, without incurring the deleterious effects otherwise resulting.

I claim as my invention:

1. A process for hydrorefining a hydrocarbon charge stock which comprises reacting said charge stock with hydrogen in contact with a molybdenum compound selected from the group consisting of diimino molybdenum chloride and a transitional metal complex thereof, and at hydrorefining conditions.

2. The process of claim 1 further characterized in that said charge stock is reacted with hydrogen in the presence of added hydrogen sulfide.

3. A process for hydrorefining a hydrocarbon charge stock which comprises admixing said charge stock with a molybdenum compound selected from the group consisting of diimino molybdenum chloride and a transitional met-a1 complex thereof, and reacting the resulting mixture with hydrogen in the presence of added hydrogen sulfide at hydrorefining conditions.

4. A process for hydrorefining an asphaltene-containing hydrocarbon charge stock which comprises admixing said charge stock with a transitional metal complex of diimino molybdenum chloride having the following structural formula:

MoCl

and wherein Me is a metal from the group of iron, cobalt, nickel, platinum, palladium, ruthenium, rhodium and manganese; reacting the resulting mixture with hydrogen in the presence of added hydrogen sulfide at hydrorefining conditions, and recovering a substantially asphaltenefree hydrorefined liquid product.

5. The process of claim 4 further characterized in that said mixture is reacted with hydrogen in the presence of from about 1.0% to about 15.0% of hydrogen sulfide.

6. The process of claim 4 further characterized in that said mixture is reacted with hydrogen at a temperature above about 225 C. and under a pressure greater than about 500 pounds per square inch.

7. A process for hydrorefining a petroleum crude oil containing pentane-insoluble asphaltenes which comprises admixing said crude oil with from about 5.0% to about 30.0% by weight of a molybdenum compound selected from the group consisting of diimino molybdenum chloride and a transitional metal complex thereof having the following structural formula:

and wherein Me is a metal from the group of iron, nickel, cobalt, platinum, palladium, ruthenium, rhodium and manganese; reacting the resulting mixture with hydrogen in the presence of from about 1.0% to about 15.0% of added hydrogen sulfide, at a temperature of from about 225 C. to about 500 C. and under a pressure within the range of from about 500 to about 5,000 pounds per square inch, and separating the resultant product efiluent into a metal-containing sludge and a substantially asphaltene-free liquid product.

8. A process for hydrorefining a hydrocarbon charge stock which comprises reacting said charge stock with hydrogen at hydrorefining conditions and in contact with a catalytic composite of an alumina-containing refractory inorganic oxide and a molybdenum compound selected from the group consisting of diimino molybdenum chloride and a transitional metal complex thereof having the following structural formula:

and wherein Me is a metal from the group of iron, cobalt, nickel, platinum, palladium, ruthenium, rhodium and manganese, and recovering a substantially asphaltenefree hydrorefined liquid product.

9. The process of claim 8 further characterized in that said catalytic composite comprises alumina, silica and from 5.0% to about 30.0% by weight of said organo molybdenum compound.

10. The process of claim 8 further characterized in that said charge stock is reacted with hydrogen in the presence of from about 1.0% to 15.0% hydrogen sulfide.

11. A process for hydrorefining a petroleum crude oil containing pentane-insoluble asphaltenes which comprises reacting said charge stock with hydrogen in the presence of from 1.0% to 15.0% hydrogen sulfide, at hydrorefining conditions including a temperature of from about 225 C. to about 500 C. and a pressure within the range of about 500 to about 5,000 pounds per square inch, in contact with a catalytic composite of silica and from about 12.0% to about 88.0% by weight of alumina, combined with a molybdenum compound selected from 9 10 the group consisting of diimino molybdenum chloride References Cited and a transitional metal complex thereof having the fol- UNITED STATES PATENTS lowing structural formula:

N N 3,196,104 7/1965 Gleim et al. 208264 \Mool 5 3,269,958 8/1966 Gatsis 208264 3,288,722 11/1966 Gleim 208216 and wherein Me is a metal from the group of iron, cobalt, nickel, platinum, palladium, ruthenium, rhodium and DELBERT GANTZ Prlmary Exammer' manganese, and recovering said crude oil substantially 10 S. P. JONES, Assistant Examiner.

free from pentane-insoluble asphaltenes.

Claims

1. A PROCESS FOR HYDROREFINING A HYDROCARBON CHARGE STOCK WHICH COMPRISES REACTING SAID CHARGE STOCK WITH HYDROGEN IN CONTACT WITH A MOLYBDENUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF DIIMINO MOLYBDENUM CHLORIDE AND A TRANSITIONAL METAL CMPLEX THEREOF, AND AT HYDROREFINING CONDITIONS.