Demetallization of hydrocarbon feed streams with nickel arsenide

Metals contained in a hydrocarbon containing feed stream are at least partially removed by contacting the hydrocarbon containing feed stream under suitable demetallization conditions with hydrogen and a catalyst composition comprising an alumina-containing support and nickel arsenide, NiAs.sub.x. The life and activity of the catalyst composition can be increased by introducing a decomposable compound of a metal selected from the group consisting of the metals of Group IV-B, Group V-B, Group VI-B, Group VII-B and Group VIII of the Periodic Table into the hydrocarbon containing feed stream during or prior to contacting the feed stream with hydrogen and the catalyst composition. The preferred nickel arsenide catalyst composition is prepared by reduction of alumina-supported nickel arsenate with hydrogen gas.

BACKGROUND OF THE INVENTION 
This invention relates to a process for removing metals from a hydrocarbon 
containing feed stream and a catalyst therefor. 
It is well known that crude oil as well as products from extraction and/or 
liquefaction of coal and lignite, products from tar sands, products from 
shale oil and similar products may contain metals such as vanadium, 
nickel, and iron. When these hydrocarbon containing feeds are 
fractionated, the metals tend to concentrate in the heavier fractions such 
as the topped crude and residuum. The presence of the metals makes further 
processing of these heavier fractions difficult since the metals generally 
act as poisons for catalysts employed in processes such as catalytic 
cracking, hydrogenation or hydrodesulfurization. 
SUMMARY OF THE INVENTION 
It is thus an object of this invention to provide a process for removing 
metals from a hydrocarbon containing feed stream so as to improve the 
processability of such hydrocarbon containing feed stream. It is a further 
object of this invention to remove metals from and thus improve the 
processability of heavier fractions such as topped crude and residuum. It 
is also an object of this invention to provide a catalyst composition 
which is useful for demetallization. 
In accordance with the present invention, a hydrocarbon containing feed 
stream, which also contains metals, is contacted with a solid catalyst 
composition comprising (a) nickel arsenide, NiAs.sub.x, and (b) alumina, 
in the presence of hydrogen under suitable demetallization conditions. It 
is believed that the metals contained in heterocyclic compounds such as 
porphyrins are removed from said heterocyclic compounds by the combination 
of heat, hydrogen and the catalyst composition of the present invention 
and are trapped in pores in the catalyst composition. Removal of the 
metals from the hydrocarbon containing feed stream in this manner provides 
for improved processability of the hydrocarbon containing feed stream in 
processes such as catalytic cracking, hydrogenation and 
hydrodesulfurization.

Other objects and advantages of the invention will be apparent from the 
foregoing brief description of the invention and the appended claims as 
well as the detailed description of the invention which follows. 
DETAILED DESCRIPTION OF THE INVENTION 
Any metal which can be bound and/or trapped in the pores of the solid 
catalyst composition of the present invention can at least partially be 
removed from a hydrocarbon containing feed stream in accordance with the 
present invention so as to produce a hydrocarbon containing stream having 
a reduced metal content. The present invention is particularly applicable 
to the removal of vanadium and nickel. 
Metals, particularly nickel and vanadium, can be removed from any suitable 
hydrocarbon containing feed streams. Suitable hydrocarbon containing feed 
streams include crude oil, petroleum products, coal pyrolyzates, products 
from extraction and/or liquefaction of coal and lignite, products from tar 
sands, products from shale oil and similar products. Suitable hydrocarbon 
feed streams include gas oil having a boiling range from about 205.degree. 
C. to about 538.degree. C., topped crude having a boiling range in excess 
of about 343.degree. C., and residuum. However, the present invention is 
particularly directed to heavy feed streams such as heavy topped crudes 
and residuum and other materials which are generally regarded as being too 
heavy to be distilled. These materials will generally contain the highest 
concentrations of metals, such as about 10-1000 ppm of vanadium and about 
5-500 ppm of nickel. They generally also contain sulfur impurities and 
frequently also nitrogen impurities and coke precursors (measured as 
Ramsbottom or Conradson carbon residue), which may at least partially be 
removed by the process of this invention. 
The demetallization catalyst employed in the process of this invention 
comprises (a) a nickel arsenide having the empirical formula NiAs.sub.x, 
wherein x can have a value ranging from about 0.33 to about 2.0 (thus 
including compounds such as Ni.sub.3 As, NiAs, Ni.sub.3 As.sub.2 and 
NiAs.sub.2), preferably ranging from about 0.6 to about 1.0; and (b) an 
alumina-containing support such as alumina, alumina-silica, 
alumina-zeolite, alumina-titania, alumina-zirconia, alumina-magnesia, 
alumina-BPO.sub.4, alumina-AlPO.sub.4 and the like and mixtures thereof, 
preferably alumina having a surface area of about 10 to about 400 m.sup.2 
/g (as determined by the BET/N.sub.2 method). It is within the scope of 
this invention to employ alumina-containing supports comprising small 
amounts (e.g., up to 1 weight-%) of oxides of metals belonging to Groups 
VB, VIB, VIIB, VIII and IB of the Periodic Table (as described in College 
Chemistry, by W. H. Nebergall et al.; D. C. Heath and Company; 1972). 
The preferred catalyst employed in the process of this invention is 
disclosed in U.S. Pat. No. 3,697,448 herein incorporated by reference. In 
the preferred method of preparation, the alumina-supported nickel arsenide 
is formed by reduction of alumina-supported nickel arsenate or arsenite, 
more preferably nickel(II) arsenate, with a reducing agent such as H.sub.2 
or CO, preferably with H.sub.2 gas at an elevated temperature. 
In the preparation of the catalyst to be employed in this invention, the 
nickel and arsenic components can be simultaneously deposited on the 
support as, for example, by precipitating nickel arsenate on the support; 
or, the support can be impregnated with the nickel and the arsenic in 
individual, sequential treatments. In either instance, sufficient nickel 
is employed so as to produce a finished catalyst composition containing 
from about 1 to about 30, preferably from about 10 to about 20, weight 
percent nickel, and sufficient arsenic is employed so as to produce a 
finished catalyst composition containing from about 0.05 to about 50, 
preferably 10 to 20, weight percent arsenic. Preferably, the 
alumina-supported nickel arsenate composition (after calcination) has a 
BET/N.sub.2 surface area of about 20 to 300 m.sup.2 /g and a pore volume 
(by water absorption) of about 0.5 to 1.5 cc/g. 
The alumina-containing catalyst base can be conventionally impregnated with 
solutions of inorganic compounds of As including acids and ammonium salts 
of arsenic, and inorganic compounds of Ni including nitrates, halides, 
sulfates, acetates and so forth of nickel. For example, arsenic pentoxide 
dissolved in water or an ammoniacal solution of As.sub.2 O.sub.5 can be 
employed as one impregnant, and an aqueous solution of Ni(NO.sub.3).sub.2 
can be employed as the second impregnant. 
In any method of preparation, the alumina-containing base, after deposition 
of nickel arsenate thereon, can be washed to remove undesirable soluble 
salts, dried and, preferably, calcined in air (e.g., at about 
800.degree.-1100.degree. F.), and then reduced with hydrogen at any 
suitable temperature and pressure which are sufficient to produce the 
active nickel arsenide. For example, reduction with hydrogen gas at 
atmospheric pressure at about 500.degree.-800.degree. F. for about 0.1-20 
hours can be used. 
Even though the impregnation of the alumina-containing support with nickel 
arsenate and subsequent reduction with hydrogen gas is the preferred mode 
of preparation, it is within the scope of this invention to employ other 
preparation techniques such as impregnation of the support with a nickel 
salt and exposure of the impregnated support to arsine gas or alkyl 
arsines or aryl arsines, or by impregnation of the support with metallic 
nickel and subsequent heating of the impregnated support in the presence 
of elemental arsenic or arsines, or by other methods known to those 
skilled in the art. 
The demetallization process of this invention can be carried out by means 
of any apparatus whereby there is achieved a contact of the catalyst 
composition with the hydrocarbon containing feed stream and hydrogen under 
suitable demetallization conditions. The process is in no way limited to 
the use of a particular apparatus. The process of this invention can be 
carried out using a fixed catalyst bed, fluidized catalyst bed, a moving 
catalyst bed or an agitated slurry type operation (e.g. in 
hydrovisbreaking). Presently preferred is a fixed catalyst bed. 
The catalyst composition can be used alone in the reactor or can be used in 
combination with essentially inert materials such as alumina, silica, 
titania, magnesia, silica-alumina, metal titanates and metal phosphates. A 
layer of the inert material and a layer of the catalyst composition can be 
used, or the catalyst composition can be mixed with the inert material. 
Use of the inert material provides for better dispersion of the 
hydrocarbon containing feed stream. Also, other catalysts such as known 
hydrogenation and desulfurization catalysts may be used in the reactor to 
achieve simultaneous demetallization, desulfurization, denitrogenation and 
hydrogenation or hydrocracking if desired. 
Any suitable reaction time between the catalyst composition and the 
hydrocarbon containing feed stream can be utilized. In general, the 
reaction time will range from about 0.05 hours to about 10 hours. 
Preferably, the reaction time will range from about 0.4 to about 4 hours. 
Thus, the flow rate of the hydrocarbon containing feed stream should be 
such that the time required for the passage of the mixture through the 
reactor (residence time) will preferably be in the range of about 0.4 to 
about 4 hours. This generally requires a liquid hourly space velocity 
(LHSV) in the range of about 0.10 to about 20 cc of oil per cc of catalyst 
per hour, preferably from about 0.25 to about 2.5 cc/cc/hr. 
The demetallization process of the present invention can be carried out at 
any suitable temperature. The temperature will generally be in the range 
of about 250.degree. C. to about 550.degree. C. and will preferably be in 
the range of about 350.degree. C. to about 450.degree. C. Higher 
temperatures do improve the removal of metals, but temperatures which will 
have adverse effects on the hydrocarbon containing feed stream, such as 
excessive coking, will usually be avoided. Also, economic considerations 
will usually be taken into account in selecting the operating temperature. 
Lower temperatures can generally be used for lighter feeds. 
Any suitable pressure may be utilized in the demetallization process. The 
reaction pressure will generally be in the range of up to about 5,000 
psig, e.g., ranging from about atmospheric pressure to about 5,000 psig. 
Preferably, the pressure will be in the range of about 100 to about 2500 
psig. Higher pressures tend to reduce coke formation but operation at high 
pressure may have adverse economic consequences. 
Any suitable quantity of hydrogen can be added to the demetallization 
process. The quantity of hydrogen used to contact the hydrocarbon 
containing feed stock will generally be in the range of about 100 to about 
10,000 standard cubic feet per barrel of the hydrocarbon containing feed 
stream and will more preferably be in the range of about 1000 to about 
6000 standard cubic feet per barrel of the hydrocarbon containing feed 
stream. 
In general, the catalyst composition is utilized for demetallization until 
a satisfactory level of metals removal is no longer achieved which is 
believed to result from the coating of the catalyst composition with the 
metals being removed. It is possible to remove the metals from the 
catalyst composition by certain leaching procedures. But these procedures 
are expensive, and it is generally contemplated that once the removal of 
metals falls below a desired level, the used catalyst will simply be 
replaced by a fresh catalyst. 
The time in which the catalyst composition will maintain its activity for 
removal of metals will depend upon the metals concentration in the 
hydrocarbon containing feed streams being treated. It is believed that the 
catalyst composition can be used for a period of time long enough to 
accumulate 20-200 wt. % of metals, mostly Ni and V, based on the initial 
weight of the catalyst composition, from oils. 
A further embodiment of this invention is a demetallization process 
comprising the step of introducing at least one decomposable metal 
compound into the hydrocarbon containing feed stream prior to its being 
contacted with the alumina-supported NiAs.sub.x catalyst in accordance 
with this invention. The metal, chemically bound in the decomposable metal 
compound, is selected from the group consisting of the metals of Group 
IV-B, Group V-B, Group VI-B, Group VII-B and Group VIII of the Periodic 
Table (as described in College Chemistry, W. H. Nebergall et al.; D. C. 
Heath and Company, 1972). Preferred metals are molybdenum, tungsten, 
manganese, chromium, and zirconium. Molybdenum is a particularly preferred 
metal which can be introduced as a carbonyl, acetate, acetylacetonate, 
octoate, naphthenate, dithiophosphate or dithiocarbamate. Molybdenum 
hexacarbonyl is a particularly preferred additive. It is believed that the 
life of the catalyst composition and the efficiency of the demetallization 
process is improved by introducing at least one of the above-cited 
decomposable metal compounds into the hydrocarbon containing feed, which 
also contains metals such as nickel and vanadium. 
Any suitable concentration of the decomposable metal compound can be added 
to the hydrocarbon containing feed stream. In general, a sufficient 
quantity of said compound will be added to the hydrocarbon containing feed 
stream to result in a concentration of the metal, chemically bound in said 
decomposable compound, in said feed stream ranging from about 1 to about 
1000 parts per million (ppm) metal, and more preferably in the range of 
about 5 to about 100 ppm metal. 
In a still further embodiment of this invention, the alumina-supported 
NiAs.sub.x catalyst composition is first impregnated with at least one of 
the above-recited decomposable metal compounds, generally dissolved in a 
suitable solvent such as naphtha or light gas oil. The thus impregnated 
alumina-supported NiAs.sub.x catalyst composition is then contacted with a 
metal containing hydrocarbon feed stream under demetallizing conditions in 
accordance with this instant invention. It is also within the scope of 
this embodiment to carry out said impregnating step at a temperature 
sufficiently high (e.g., about 200.degree.-400.degree. C.) so as to at 
least partially decompose said decomposable metal compound. The catalyst 
composition containing said at least partially decomposed metal compound 
is then contacted with a metal containing hydrocarbon feed under 
demetallizing conditions in accordance with the present invention. 
If the demetallization process of the present invention is used in a 
refinery where hydrodesulfurization is practiced, the demetallization 
process of this invention can be employed before or after a 
hydrodesulfurization step. The fact that the feedstream has been passed 
through a hydrodesulfurization process does not affect the demetallization 
process of the present invention. It is, however, preferred to carry out 
the demetallization of this invention first, and thereafter desulfurize at 
least a portion of the products, preferably by a catalytic hydrotreating 
process, which generally removes more metals, sulfur, nitrogen and coke 
precursors. Generally, at least a portion of the thus hydrotreated product 
stream is subsequently cracked in a cracking reactor, e.g. in a fluidized 
catalytic cracking unit, so as to produce gasoline and other useful fuels. 
If, however, the sulfur content of the hydrocarbon feed is low, the 
desulfurization step can be omitted and the at least partially 
demetallized hydrocarbon stream can be fed directly to a cracking reactor 
and treated under cracking conditions so as to produce gasoline and other 
useful fuels. 
The following examples are presented in further illustration of the 
invention and are not to be considered as unduely limiting the scope of 
this invention. 
EXAMPLE I 
In this example the preparation of two alumina-supported nickel catalysts 
is described. The NiAs.sub.x --Al.sub.2 O.sub.3 catalyst of this invention 
is prepared as follows. 200 grams (0.687 moles) of Ni(NO.sub.3).6H.sub.2 O 
were dissolved in water. Then 230 grams of Catapal N alumina marketed by 
CONOCO, (a unit of E. I. Du Pont de Nemours & Co., Teterboro, N.J.) were 
slurried with this solution, and 53 grams (0.23 moles) of As.sub.2 O.sub.5 
completely dissolved in water containing a few drops of concentrated 
nitric acid were added. Then an aqueous, 9-10 molar ammonia solution was 
slowly added to the slurry with stirring until the pH was about 7.5-8.0. 
After 1-2 days of standing, additional 7 grams of As.sub.2 O.sub.5 
completely dissolved in water plus enough ammonia solution to adjust the 
pH to about 8 were added. The slurry was filtered through a Buchner 
funnel. The filter cake comprising Al.sub.2 O.sub.3 and Ni.sub.3 
(AsO.sub.4).sub.2 precipitate was washed, dried at 105.degree. C. for 
about two days, and calcined at about 1000.degree. F. overnight. The 
calcined material had a surface area (BET/N.sub.2) of 175 m.sup.2 /g, a 
pore volume (by water absorption) of 0.8 cc/g, a Ni content of 13.3 
weight-% and an As content of 12.4 weight-%. As indicated in Example II, 
the Ni.sub. 3 (AsO.sub.4).sub.2 was reduced in a hydrogen stream before 
demetallization runs to NiAs.sub.x, essentially in accordance with the 
disclosure in Example I of U.S. Pat. No. 3,697,448. This catalyst was 
employed in invention runs 1,3,6,9,12,15,18,20 (see Table I). 
A control catalyst, NiO on Al.sub.2 O.sub.3, was prepared as follows. 100 
grams of Catapal N alumina were slurried in about 100 cc of water. Then a 
solution of 87 grams of Ni(NO.sub.3).sub.2.6H.sub.2 O in about 100 cc of 
water was added. The mixture was heated to boiling for about one hour, 
neutralized with a concentrated ammonia solution to a pH of about 8, and 
heated again to boiling. The hot mixture was then filtered through a 
Buchner funnel. The filter cake was washed, dried overnight at about 
230.degree. F. and calcined for one hour at about 1000.degree. F. The 
calcined, hard material was crushed and sieved. The 10/40 mesh fraction 
was used for control demetallization runs 2,4,7,10,13,16 (see Table I) 
after heating in a hydrogen stream (see Example II). The Ni content of 
this NiO--Al.sub.2 O.sub.3 catalyst (before heating in hydrogen) was about 
14 weight-%; its surface area was about 175 m.sup.2 /g; its pore volume 
was about 0.8 cc/g. 
EXAMPLE II 
This example illustrates the experimental setup for investigating the 
demetallization of heavy oils by employing various nickel catalysts. A 
stainless steel trickle bed reactor, 28.5 inches long and 0.75 inches in 
diameter, fitted inside with a 0.25 O.D. axial thermocouple well, was 
filled with a top layer (3.5 inches below the feed inlet) of about 50 cc 
of low surface area (less than 1 m.sup.2 /gram) .alpha.-alumina, a middle 
layer of 50 cc of a nickel catalyst, and a bottom layer of about 50 cc of 
.alpha.-alumina. The reactor tube was heated by a Thermcraft 
(Winston-Salem, N.C.) Model 211 3-zone furnace. The reactor temperature 
was usually measured in four locations along the reactor bed by a 
travelling thermocouple that was moved within the axial thermocouple well. 
First the reactor was heated to about 400.degree.-425.degree. C. in a 
stream of hydrogen having a flow rate of about 23-26 liter/hr, at a total 
pressure of about 1000 psig. During this phase Ni.sub.3 (AsO.sub.4).sub.2 
contained in Catalyst A was reduced to NiAs.sub.x. Then oil was pumped by 
means of a LAPP Model 211 (General Electric Company) pump to a metallic 
mixing T-pipe where it was mixed with a controlled amount of hydrogen gas. 
The oil/hydrogen mixture was pumped downward through a stainless steel 
trickle bed reactor. The liquid product was collected in a receiver flask, 
filtered through a glass frit and analyzed, whereas exiting hydrogen gas 
was vented. Vanadium and nickel contents in oil were determined by plasma 
emission analysis. 
The feed was a mixture of 26 weight-% toluene and 74 weight-% Venezuelan 
Monagas pipeline oil having an API gravity of about 17-18. The hydrogen 
pressure was maintained at about 1000 psig in all experiments which 
generally lasted from about 2-6 hours. The reactor temperature (average of 
thermocouple readings at four reactor locations) was about 
375.degree.-435.degree. C. The liquid hourly space velocity (LHSV) of the 
feed ranged from about 0.5 cc/cc catalyst/hour to about 2 cc/cc 
catalyst/hour. 
EXAMPLE III 
Results of heavy oil demetallization runs at 425.degree. C. and 400.degree. 
C. in accordance with the procedure described in Example II are summarized 
in Table I. 
TABLE I 
__________________________________________________________________________ 
Feed Product 
Run Total Total 
Removal of 
Temp 
LHSV Time 
Vanadium 
Nickel 
(V + Ni) 
Vanadium 
Nickel 
(V + Ni) 
(V + Ni) 
Run 
Catalyst 
(.degree.C.) 
(cc/cc/hr) 
(hours) 
(ppm) (ppm) 
(ppm) 
(ppm) (ppm) 
(ppm) 
(%) 
__________________________________________________________________________ 
1 NiAs.sub.x --Al.sub.2 O.sub.3 
425 0.45 6 225 58 283 0.2 0 0.2 100 
2 NiO--Al.sub.2 O.sub.3 
425 0.44 6 220 65 285 4.2 4.9 
9.1 97 
3 NiAs.sub.x --Al.sub.2 O.sub.3 
425 1.00 3 225 58 283 12.5 7.5 
20.0 
93 
4 NiO--Al.sub.2 O.sub.3 
425 0.96 4 220 65 285 34.9 21.8 
56.2 
80 
5 Harshaw.sup.1 
425 1.00 3 225 58 283 80.6 25.3 
105.9 
63 
6 NiAs.sub.x --Al.sub.2 O.sub.3 
425 1.50 2 225 58 283 25.1 8.9 
34.0 
88 
7 NiO--Al.sub.2 O.sub.3 
425 1.46 3 220 65 285 62.9 26.3 
89.2 
69 
8 Harshaw 425 1.51 3 225 58 283 95.8 29.3 
125.1 
56 
9 NiAs.sub.x --Al.sub.2 O.sub.3 
400 0.47 6 225 58 283 45.0 17.6 
62.6 
78 
10 NiO--Al.sub.2 O.sub.3 
400 0.42 7 220 65 285 83.5 29.8 
113.3 
60 
11 Harshaw 400 0.48 6 225 58 283 88.4 27.0 
115.4 
59 
12 NiAs.sub.x --Al.sub.2 O.sub.3 
400 0.97 3 225 58 283 131.0 33.5 
164.5 
42 
13 NiO--Al.sub.2 O.sub.3 
400 0.95 3 220 65 285 179.5 43.4 
222.9 
22 
14 Harshaw 400 1.01 3 225 58 283 134.0 39.4 
173.4 
39 
15 NiAs.sub.x --Al.sub.2 O.sub.3 
400 1.52 2 225 58 283 177.0 41.2 
218.2 
23 
16 NiO--Al.sub.2 O.sub.3 
400 1.45 2 220 65 285 .sup. 250.9.sup.2 
52.6 
.sup. 303.5.sup.2 
.sup. 0.sup.2 
17 Harshaw 400 1.53 2 225 58 283 164.0 43.8 
207.8 
27 
18 NiAs.sub.x --Al.sub.2 O.sub.3 
375 0.45 6 225 58 283 148.0 36.2 
184.2 
35 
19 Harshaw 375 0.45 6 220 65 285 126.0 35.2 
161.2 
43 
20 NiAs.sub.x --Al.sub.2 O.sub.3 
375 0.95 3 225 58 283 199.0 43.6 
242.6 
14 
21 Harshaw 375 0.98 3 220 65 285 169.0 44.4 
213.4 
25 
__________________________________________________________________________ 
.sup.1 a commercial oil hydrofining catalyst, marketed by Harshaw Chemica 
Company, having a surface area of about 178 m.sup.2 /g, a MoO.sub.3 
content of about 7.3 weight %, a CoO content of about 0.92 weight %, a Ni 
content of about 0.53 weight %, and Al.sub.2 O.sub.3 as the support; 
.sup.2 result appears to be erroneous. 
Data in Table I show that the NiAs.sub.x --Al.sub.2 O.sub.3 catalyst (i.e., 
reduced Ni.sub.3 (AsO.sub.4).sub.2 on Al.sub.2 O.sub.3) is clearly 
superior in removing metals (V, Ni) at 425.degree. C. versus an Al.sub.2 
O.sub.3 -supported NiO catalyst and the commercial Harshaw hydrofining 
catalyst. At 400.degree. C., NiAs.sub.x --Al.sub.2 O.sub.3 was more 
effective than (Ni)--Al.sub.2 O.sub.3 and also more effective than the 
commercial Harshaw catalyst. 
EXAMPLE IV 
This example illustrates the effect of the addition of small amounts of a 
decomposable molybdenum compound, Mo(CO).sub.6, to an undiluted Monagas 
pipeline oil feed containing about 336 ppm V and about 87 ppm Ni on the 
removal of these metals in the presence of the Harshaw control catalyst 
(see footnote 1 of Table I). LHSV of the feed for both runs ranged from 
about 1.0 to 1.1 cc/cc catalyst/hr, the temperature was about 765.degree. 
F. (407.degree. C.), the pressure was about 2250 psig, and the hydrogen 
feed rate was about 4800 SCF/barrel oil. Experimental data are summarized 
in Table II. 
TABLE II 
______________________________________ 
Run 22 (Control) Run 23 (Control) 
Days on 
PPM Mo % Removal PPM Mo % Removal 
Stream in Feed of (Ni + V) in Feed 
of (Ni + V) 
______________________________________ 
5 0 64 17 72 
12-13 0 62 17 71 
17 0 59 7 70 
20-21 0 61 7 65 
26 0 58 7 64 
32-33 0 53 7 65 
41 0 52 7 70 
52-53 0 41 7 66 
58-59 0 43 4 65 
______________________________________ 
Data in Table II clearly show the beneficial effect of added small amounts 
of Mo (as Mo(CO).sub.6) to the feed on the demetallization of the oil when 
a commercial hydrofining Harshaw catalyst was used. Based on these 
results, it is believed that a similarly beneficial demetallization effect 
of Mo(CO).sub.6 in the feed is also obtained when the catalyst of this 
invention, NiAs.sub.x, is employed.