Method of hydrorefining catalyst manufacture

A catalytic composite of Group VIB metal, Group VIII metal and a porous alumina carrier material is manufactured by controlling a water of hydration of pseudo-boehmite contained in an amorphous alumina hydrate slurry in the range of 1.20-1.50 mols per mol of Al.sub.2 O.sub.3 ; forming an alumina hydrate obtained from this slurry into alumina particles and drying; and then calcining the alumina particles in a steam-containing atmosphere to thereby obtain a porous alumina carrier material, the resulting porous alumina carrier material being subsequently incorporated with catalytically effective amounts of a Group VIB metal compound and a Group VIII metal compound.

BACKGROUND OF THE INVENTION 
The present invention relates to the method of manufacturing a 
hydrorefining catalyst, in particular relates to the method of 
manufacturing a catalyst suitably employed in the hydrodesulfurization 
process which comprises treating a hydrocarbon feed stock containing a 
sulfur compound and a relatively large amount of contaminants that 
deactivate the catalytic composite, in particular a residual oil, in the 
presence of hydrogen. 
In general, the hydrorefining catalyst comprises carrying a hydrogenating 
metal component on a porous alumina. Said hydrogenating metal component 
includes one metal component selected from Group VIB and one or more of 
metal components selected from Group VIII of Periodic Table. The activity 
of the hydrorefining catalyst deteriorates, in the initial stage of 
treating a heavy hydrocarbon oil, mainly due to the separation of 
carbonaceous substances on the catalyst surface, said carbonaceous 
substances being resultant from decomposition of asphaltenes contained in 
the feed stock, and the activity more deteriorates as the treating time is 
prolonged. This is because vanadium and nickel compounds bound with 
asphaltenes come to deposit on the catalyst surface with the lapse of 
time. Accordingly, in proportion to the tendency that the hydrocarbon feed 
stock is becoming heavy, there is an aceute demand for a hydrorefining 
catalyst that is resistable against metal contaminants containing vanadium 
and nickel and is capable of holding a high desulfurization activity for a 
long period of time. 
The activity of the catalyst utilized in catalytic hydrorefining, in 
particular hydrodesulfurization, of heavy hydrocarbon oils is in close 
contact with the pore volume, pore distribution and pore diameter of the 
catalyst, and the pore distribution and pore diameter of the catalyst are, 
as a matter of course, influenced by the pore volume, pore distribution 
and pore diameter of the porous alumina utilized as the carrier material 
for the catalyst. Generally speaking, the porous alumina utilized as the 
carrier material for the hydrorefining catalyst may be made from 
pseudo-boehmite, but Japanese Patent Publication No. 35893/1981 
Specification discloses that the use of an alumina hydrate containing a 
pseudo-boehmite having a crystal size grown in the range of 40-80 A as a 
precursor of a porous alumina permits to obtain alumina wherein the 
greater part of the total pore volume is occupied by pores having a pore 
diameter of 600 A or less. 
On the other hand, Japanese Laid Open Patent Application No. 27036/1980 
Specification discloses a hydrodesulfurizing catalyst comprising a porous 
alumina carrier and Group VIB and VIII metal components carried thereon, 
wherein the average pore diameter measured by nitrogen adsorption method 
is in the range of 100-130 A and the pore volume of pores having a 
diameter of 90-140 A occupies 70% of the pore volume of pores having a 
diameter up to 600 A, and mentions that this hydrodesulfurizing catalyst 
can exhibit a high desulfurizing activity because it prevents entrance of 
asphaltenes bound with metal contaminants into pores. 
SUMMARY OF THE INVENTION 
The present invention provides a method of manufacturing a hydrorefining 
catalyst, in particular a hydrodesulfurizing catalyst, which can hold a 
high desulfurizing activity for a long period of time even when 
asphaltenes containing metal contaminants enter into pores, whereby 
vanadium and nickel deposit on the catalyst. 
In other words, the method of manufacturing a hydrorefining catalyst 
according to the present invention comprises the steps of controlling a 
water of hydration of pseudo-boehmite contained in an amorphous alumina 
hydrate slurry in the range of 1.20-1.50 mols per mol of Al.sub.2 O.sub.3 
; forming an alumina hydrate obtained by dehydrating this slurry into 
alumina particles having desired shape and dimensions and drying; then 
calcining the alumina particles in a steam-containing atmosphere into a 
porous alumina; and thereafter carrying catalytically effective amounts of 
hydrogenating metal components on this porous alumina.

DETAILED DESCRIPTION OF THE INVENTION 
The amorphous alumina hydrate slurry may be prepared in a usual manner, and 
typically prepared by mixing a solution of sodium aluminate with a 
solution of acid aluminate such as a solution of aluminum sulfate. The 
pseudo-boehmite contained in the thus obtained amorphous alumina hydrate 
slurry is unsuited for a precursor of the porous alumina carrier material 
of the present invention because the water of hydration of said 
pseudo-boehmite is about 1.8 mols per mol of Al.sub.2 O.sub.3. According 
to the present invention, therefore, the amount of water of hydration of 
the pseudo-boehmite present in the slurry is controlled in the range of 
1.20-1.50 mols per mol of Al.sub.2 O.sub.3. Controlling of the water of 
hydration is effected by removing a by-product salt from said amorphous 
alumina hydrate slurry and thereafter stirring the slurry under the 
conditions: pH 8-12 and temperature 50.degree. C. or more, preferably 
80.degree. C. or more. The stirring time depends upon the pH and 
temperature of the slurry. However, it may generally be said that the 
water of hydration of pseudo-boehmite can be controlled in the range of 
1.20-1.50 mols per mol of Al.sub.2 O.sub.3 by stirring for a period of 
about 3-150 hours. 
The slurry of pseudo-boehmite controlled in the amount of water of 
hydration is then dehydrated and thereafter formed into alumina particles 
having desired shape and dimensions and dried. Thereafter, the dried 
alumina particles are calcined at a temperature of 400.degree.-800.degree. 
C., preferably 550.degree.-700.degree. C., for 1-10 hours in an atmosphere 
containing 20 mol% or more, preferably 40 mol% or more of steam. Calcining 
of the alumina particles in the presence of steam is very important to the 
present invention as well as controlling of the water of hydration of 
pseudo-boehmite. 
As stated previously, from the pseudo-boehmite whose water of hydration is 
in the range of 1.20-1.50 mols per mol of Al.sub.2 O.sub.3 there can be 
obtained the porous alumina in which the pore volume of pores having a 
diameter of 600 A or less occupies the greater part of the total pore 
volume and additionally the pore size distribution is narrow. However, so 
far as calcining of the pseudo-boehmite is effected in the air according 
to the prior art method, the resulting porous alumina takes the pore shape 
of ink bottle where the inside diameter is larger than the port diameter. 
However, when calcining of the pseudo-boehmite is effected in the 
atmosphere containing at least 20 mol% of steam like the present 
invention, there can be obtained the porous alumina having cylindrical 
pores where the port diameter has substantially the same width as the 
inside diameter. In this connection, it is to be noted that the porous 
alumina obtained according to the method of the present invention is 
featured in that the average pore diameter is in the range of 130-170 A, 
the pore volume of pores having a diameter of 0-600 A is 0.60 ml/g or 
more, the pore volume of pores having a diameter of 130-200 A occupies 50% 
or more of the pore volume of pores having a diameter of 0-600 A, and the 
pore volume of pores having a diameter of 0-60 A is 5% or less of the pore 
volume of pores having a diameter of 0-600 A. 
In the hydrorefining catalyst using the porous alumina as carrier material, 
when the pores of the porous alumina take the shape of ink bottle, the 
catalyst activity decays in a relatively short time because the port of 
the pore is blocked up only by deposition of a small amount of metal 
contaminants present in the feed stock on the catalyst, whilst when the 
pores of the porous alumina take the shape of cylinder whose port diameter 
is enlarged, the catalyst is allowed to hold a high activity for a long 
period of time because blocking up of the pore does not take place even 
when metal contaminants somewhat deposit in the vicinity of the port of 
the pore. 
According to the method of the present invention, it is possible to 
deposite the hydrogenating metal active components on the porous alumina 
obtained by calcination in the presence of steam. In this instance, as the 
metal active components there can be used one metal component selected 
from Group VIB metals and at least one metal component selected from Group 
VIII metals of Periodic Table. Typically, as the VIB metal is selected 
molybdenum or tungsten and as the Group VIII metals are selected nickel 
and cobalt. Deposition of the metal active components on the porous 
alumina is effected by the prior art method, for instance, such as 
kneading method, impregnation method or the like. Preferably, the amount 
of the Group VIB metal deposited is in the range of 8-20 wt.% of the final 
catalyst on the basis of metal oxide and the amount of the Group VIII 
metal deposited is in the range of 0.1-5 wt.% of the final catalyst on the 
basis of metal oxide. The typical hydrorefining catalyst according to the 
present invention contains the nickel component in the range of 0.5-3 wt.% 
on the basis of NiO, the cobalt component in the range of 0.5-3 wt.% on 
the basis of CoO, and the molybdenum component in the range of 10-15 wt.% 
on the basis of MoO.sub.3. 
The hydrorefining catalyst of the present invention, which comprises 
depositing the metal active component on the porous alumina, is subjected 
to drying, calcining and activating treatments according to the prior art 
method, and thus can be used in the hydrodesulfurization of heavy 
hydrocarbon oils, in particular residual oils. The hydrodesulfurization of 
residual oils is generally effected using a fixed-bed reactor under the 
conditions: temperature 330.degree. C.-450.degree. C., hydrogen pressure 
60-210 Kg/cm.sup.2, liquid hourly space velocity (LHSV) 0.1-1.5 and 
hydrogen/oil ratio 300-3000. 
EXAMPLE 1 
80 Kg of a solution of sodium aluminate containing 5.0 wt.% alumina were 
poured into a 200 l-stainless tank and heated to 60.degree. C. This 
solution was maintained at 60.degree. C. with stirring and added with 280 
g of a 50 wt.% gluconic acid aqueous solution. Then, a 2.5 wt.% 
alumina-containing aluminum sulfate solution heated to 60.degree. C. was 
added thereto in about 10 minutes, thereby obtaining a slurry having the 
pH 7.0. The amount of the aluminum sulfate solution required for obtaining 
the slurry having the pH 7.0 was 94 Kg. This slurry was filtered. The thus 
obtained filter cake was washed with a 0.2 wt.% ammonia water heated to 
50.degree. C. for removing a by-product salt, thereby obtaining a 
pseudo-boehmite-containing amorphous alumina hydrate (a). The water of 
hydration of this amorphous alumina hydrate (pseudo-boehmite) was 1.80 
mols. 
The above mentioned alumina hydrate (a) was added with a small amount of 
ammonia water to thereby obtain a slurry having the alumina concentration 
8.8 wt.% and the pH 10.5. This slurry was received in a container equipped 
with a reflux condenser and a stirrer and stirred at 90.degree. C. for 20 
hours. Thereafter, 20 Kg of the slurry were transferred to a 30 l-kneader 
and kneaded with heating, thereby obtaining a plasticizable alumina cake 
(b). The water of hydration of this alumina cake (b) was 1.42 mols. 
This alumina cake (b) was extruded into a 1.6 mm.phi.-cylindrical body, and 
this cylindrical body was dried at 110.degree. C. for 16 hours. The 
resulting dry cylindrical body was received in a furnace where the amounts 
of air and steam fed therein can be controlled, and calcined at 
650.degree. C. for 3 hours in a 40 mol% steam-containing atmosphere, 
thereby obtaining a porous alumina carrier material. The physical 
characteristics of this alumina carrier material are as shown below: 
##EQU1## 
Next, 60.0 g of ammonium paramolybdate, 20.0 g of cobalt nitrate and 24.7 g 
of nickel nitrate were dissolved in ammonia water to obtain a solution of 
the gross volume 360 ml. This solution was poured in a container having 
received 500 g of the above mentioned porous alumina carrier material 
therein and held under reduced pressure for impregnating the alumina 
carrier material. Thereafter, it was dried at 110.degree. C. for 1 hour 
with rotating, and in succession calcined at 550.degree. C. for 1 hour. 
The obtained catalyst was observed to have the pore volume of 0.63 ml/g 
and the specific surface area of 170 m.sup.2 /g and to contain 1.1 wt.% of 
nickel component on the basis of NiO, 0.9 wt.% of cobalt component on the 
basis of CaO and 10.5 wt.% of molybdenum component on the basis of 
MoO.sub.3. This catalyst was named Catalyst A. 
EXAMPLE 2 
The amorphous alumina hydrate (a) prepared by the same procedure as Example 
1 was added with water and 15 wt.% ammonia water to thereby obtain a 
slurry having the alumina concentration 9.2 wt.% and the pH 10.9. 80 Kg of 
this slurry were received in a container equipped with a reflux condenser 
and a stirrer and stirred at 95.degree. C. for 72 hours. 20 Kg of the 
resulting alumina hydrate slurry were transferred to a 30 l-kneader and 
kneaded with heating, thereby obtaining a plasticizable alumina cake. The 
water of hydration of this alumina cake was 1.23 mols. This alumina cake 
was extruded into a 1.6 mm.phi.-cylindrical body. Then, this cylindrical 
body was dried at 110.degree. C. for 16 hours, and thereafter calcined at 
600.degree. C. for 3 hours in an atmosphere containing 57 mol% steam by 
means of the same furnace as used in Example 1, thereby obtaining a porous 
alumina carrier material. The physical characteristics of this alumina 
carrier material are as shown below: 
##EQU2## 
500 g of the above porous alumina carrier material was impregnated with an 
aqueous solution of molybdenum trioxide in ammonia water under reduced 
pressure, and then dried at 120.degree. C. In succession, same was 
impregnated with an aqueous solution of cobalt nitrate, dried and 
calcined, thereby preparing Catalyst B. Catalyst B was observed to have 
the pore volume of 0.62 ml/g and the specific surface area of 162 m.sup.2 
/g and to contain the metal active components in the amounts of 3.75 wt.% 
on the basis of CoO and 12.5 wt.% on the basis of MoO.sub.3. 
Comparative Example 1 
A slurry was obtained by adding water to the amorphous alumina hydrate (a) 
obtained by the same procedure as used in Example 1. This slurry was 
itself sprayed and dried to thereby obtain 67.2 wt.% alumina-containing 
powder. 3.5 Kg of said powder was added with 3500 ml of 7.5 wt.% ammonia 
water and kneaded into a plasticizable alumina cake. Thereafter, this cake 
was extruded into a 1.6 mm.phi.-cylindrical body. Then, this cylindrical 
body was dried at 110.degree. C. for 16 hours. The dry cylindrical body 
was subjected 3 hours' calcination at 650.degree. C. in the air, thereby 
obtaining a porous alumina carrier material. The physical characteristics 
of this alumina carrier material are as shown below: 
##EQU3## 
Nickel, cobalt and molybdenum components were then deposited on the above 
mentioned porous alumina carrier material according to the exactly same 
procedure as Example 1 to thereby obtain Catalyst C. Catalyst C was 
observed to have the pore volume of 0.52 ml/g and the specific surface 
area of 227 m.sup.2 /g, and to be identical in the amounts of metal active 
components with Catalyst A. 
Comparative Example 2 
A porous alumina carrier material was obtained by repeating the exactly 
same procedure as Example 1 except that the dry cylindrical body was 
subjected to 3 hours' calcination at 550.degree. C. in the air in place of 
3 hours' calcination at 650.degree. C. in the presence of steam. The 
physical characteristics of this alumina carrier material are as shown 
below: 
##EQU4## 
Nickel, cobalt and molybdenum components were then deposited on the above 
mentioned porous alumina carrier material according to the exactly same 
procedure as Example 1 to thereby obtain Catalyst D. Catalyst D was 
observed to have the pore volume of 0.63 ml/g and the specific surface 
area of 211 m.sup.2 /g, and to be identical in the amounts of metal active 
components with Catalyst A. 
Comparative Example 3 
A solution of sodium aluminate containing 5.0 wt.% alumina and a solution 
of aluminum sulfate containing 2.5 wt.% alumina were mixed to prepare an 
amorphous alumina hydrate slurry. This slurry was added with chi-alumina, 
and same was treated at 180.degree. C. for 20 hours in an autoclave. This 
slurry was filtered to obtain a filter cake. This filter cake was washed 
with ammonia water, thereby obtaining a pseudo-boehmite-containing alumina 
hydrate, the water of hydration of said pseudo-boehmite being 1.14 mols. 
Next, this alumina hydrate was transferred to a kneader and kneaded 
therein at elevated temperature, thereby obtaining an alumina cake. 
Thereafter, this alumina cake was extruded into a 1.6 mm.phi. cylindrical 
body. This cylindrical body was dried at 110.degree. C. for 16 hours. This 
dry cylindrical body was calcined at 550.degree. C. for 3 hours in the air 
to thereby obtain a porous alumina carrier material. The physical 
characteristics of this alumina carrier material are as shown below: 
##EQU5## 
Nickel, cobalt and molybdenum components were then deposited on this porous 
alumina carrier material according to the exactly same procedure as 
Example 1 to thereby prepared Catalyst E. Catalyst E was observed to have 
the pore volume of 0.60 ml/g and the specific surface area of 141 m.sup.2 
/g, and to be identical in the amounts of metal active components with 
Catalyst A. 
Comparative Example 4 
The dry cylindrical body obtained according to the procedure of Comparative 
Example 1 was calcined at 650.degree. C. for 3 hours in an atmosphere 
containing 40 mol% steam to thereby obtain a porous alumina carrier 
material. The physical characteristics of this alumina carrier material 
are as shown below: 
##EQU6## 
Nickel, cobalt and molybdenum components were then deposited on the 
aforesaid porous alumina carrier material according to the exactly same 
procedure of Example 1 to thereby prepare Catalyst F. 
Catalyst F was observed to have the pore volume of 0.51 ml/g and the 
specific surface area of 225 m.sup.2 /g and to be identical in the amounts 
of metal components with Catalyst A. 
EXAMPLE 3 
Hydrodesulfurization of Kuwait topped crude was effected using Catalyst A 
to Catalyst F obtained in the respective examples and comparative 
examples, wherein a fixed-bed reactor with an outside diameter of 27 
mm.phi., an inside diameter of 19 mm.phi. and a length of 3 m was employed 
and the amount of each catalyst used was 150.0 g. The properties of feed 
stock and test conditions are shown in Table I and Table II respectively. 
And, the properties of product oil after the lapse of 100 hours on stream 
are shown in Table III. 
TABLE I 
______________________________________ 
Properties of feed stock 
______________________________________ 
Specific gravity (15/4.degree. C.) 
0.973 
Sulfur content (wt. %) 
4.3 
Nitrogen content (ppm) 
2100 
Asphaltene content (wt. %) 
3.9 
Vanadium content (ppm) 
59.0 
Nickel content (ppm) 
15.5 
______________________________________ 
TABLE II 
______________________________________ 
Test conditions 
______________________________________ 
Reaction temperature (.degree.C.) 
380 
Pressure (Kg/cm.sup.2) 
150 
LHSV (hr.sup.-1) 1.0 
Hydrogen/oil ratio (Nm.sup.3 /Kl) 
700 
Hydrogen concentration (mol %) 
90 
______________________________________ 
TABLE III 
______________________________________ 
Properties of product oil after 
100 hours on stream 
Catalyst 
A B C D E F 
______________________________________ 
Specific 0.916 0.916 0.920 0.917 0.917 0.919 
gravity 
(15/4.degree. C.) 
Sulfur 0.82 0.88 1.03 0.74 1.08 1.05 
content 
(wt. %) 
Desulfuri- 
80.9 79.5 76.0 82.8 74.9 75.6 
zation 
ratio (%) 
Nitrogen 1100 1100 1100 1100 1100 1100 
content 
(ppm) 
Asphaltene 
1.2 1.2 2.0 1.5 1.1 2.0 
content 
(wt. %) 
Vanadium 10.5 11.2 17.2 15.6 10.5 17.0 
content 
(ppm) 
Nickel 5.1 5.2 7.3 6.6 4.9 7.3 
content 
Demetall- 
79.1 78.0 67.1 70.2 79.3 67.4 
ing ratio 
(%) 
______________________________________ 
It is evident from the test results shown in Table III that Catalyst A and 
Catalyst B prepared according to the method of the present invention are 
higher in desulfurizing activity than Catalyst C and Catalyst E using the 
porous alumina carrier material obtained by calcining, in the air, the 
pseudo-boehmite having the water of hydration deviating from the range of 
1.20-1.50 mols. Catalyst D is not inferior in respect of the desulfurizing 
activity as compared with Catalyst A and Catalyst B at the lapse of 100 
hours on stream, but can not surpass the catalyst prepared by the method 
of the present invention in respect to the catalyst life as shown in 
Example 4 referred to afterwards. 
EXAMPLE 4 
Catalyst A and Catalyst D were examined in respect of the catalyst life. 
The test conditions employed herein were exactly the same as Example 3 
except that the hydrogen/oil ratio was 1000 Nm.sup.3 /Kl, the hydrogen 
concentration was 80 mol% and further the reaction temperature was 
elevated in proportion to lowering of the catalytic activity so that the 
sulfur content in the product oil may always be maintained less than 1.0 
wt.% throughout the test period. 
The obtained test results are shown in the accompanying drawing. As is 
evident from the drawing, Catalyst D exhibits a higher activity than 
Catalyst A before the lapse of about 3200 hours on stream, but its 
activity deteriorates rapidly after the lapse of 3500 hours on stream. In 
contrast, Catalyst A prepared according to the method of the present 
invention can maintain the activity in a high degree even after the lapse 
of 3500 hours on stream. 
After the completion of the life test, the amounts of vanadium, nickel, 
carbon and sulfur deposited on the respective catalyst were measured. The 
amounts of components deposited on fresh catalysts are shown by weight in 
Table IV. 
TABLE IV 
______________________________________ 
Deposits on catalysts 
Catalyst A D 
______________________________________ 
Vanadium 24.5 17.0 
Nickel 5.4 4.2 
Carbon 18.3 13.5 
Sulfur 26.2 20.1 
______________________________________ 
As is evident from data shown in Table IV, it is worthy of attention that 
for all that Catalyst A carries thereon larger amounts of metal 
contaminants such as vanadium, nickel and the like than Catalyst D does, 
Catalyst A has a desulfurizing activity life more prolonged than that of 
Catalyst D as indicated in the drawing.