Use of phosphrous to enhance the acid sites of FCC catalysts

The present invention discloses aqueous methods for enhancing the acid sites of fluid catalytic cracking (FCC) catalysts. The methods comprise the steps of contacting an FCC catalyst, either spent or fresh, with an aqueous solution comprising water, and a source of both phosphorus and aluminum. Optionally the solution includes sulfurous or sulfuric acid. The phosphorus is provided by phosphoric acid, phosphorous acid or ammonium dihydrogen phosphate. The aluminum is provided by an aluminum source selected from the group consisting of the alumina trihydrates and aluminum oxide. Chloride contamination of the aluminum source should be minimal, preferably less than about 1000 ppm chloride, more preferably less than about 200 ppm chloride. The pH of the aqueous solution is adjusted to about 3-12 by the addition of a sufficient quantity of an aqueous ammonium solution. The FCC catalyst is added to this solution, preferably with stirring, in a weight ratio of about 1 part catalyst to about 1-10 parts water to prepare an aqueous slurry. Upon stabilization of the pH of the aqueous slurry, enhancement of the acid sites of the catalyst is achieved and the catalyst may be separated from the slurry and, if desired, washed. This simple, aqueous process reduces the level of many metal poisons, including nickel and vanadium, on the FCC catalyst and produces a catalyst having an enhanced number of acid reaction sites.

BACKGROUND IN THE INVENTION 
I. Field of the Invention 
The present invention generally relates to methods for preparing fluid 
catalytic cracking (FCC) catalysts having enhanced acid sites. More 
specifically, the present invention is directed to aqueous methods for 
preparing improved FCC catalysts by contacting a catalyst with an aqueous 
solution including sources of both phosphorus and aluminum having specific 
characteristics and under specified conditions to enhance the acid sites 
of the catalyst. 
II. Description of the Background 
Catalytically controlled processes, including fluid catalytic cracking 
(FCC), are valuable refining processes employed to upgrade heavy 
hydrocarbons to higher valued products. In particular, the cracking of 
hydrocarbon feedstocks to produce hydrocarbons of preferred octane rating 
which boil in the gasoline range is widely practiced. This cracking uses a 
variety of solid catalysts typically comprising at least one synthetic 
crystalline material to give more valuable end products. Cracking is 
ordinarily employed to produce gasoline as the most valuable product. 
Cracking is generally conducted at temperatures of about 750-1100.degree. 
F., preferably about 850-950.degree. F. and at pressures up to about 2000 
psig, preferably about atmospheric to about 100 psig. In cracking, the 
feedstock is usually a petroleum hydrocarbon fraction such as straight run 
or recycled gas oils or other normally liquid hydrocarbons boiling above 
the gasoline range. 
Over 1100 tons per day of FCC catalyst is used worldwide in over 200 Fluid 
Catalytic Cracking Units (FCCUs). During the cracking reaction, the 
catalyst is contaminated by elements deposited from feedstocks. Some 
contaminants, like the alkali metals, deactivate the catalyst without 
changing the product distribution. Others, however, including iron, 
nickel, vanadium and copper, effectively poison the catalyst by altering 
the selectivity and activity of the cracking reactions if allowed to 
accumulate on the catalyst. A catalyst, so poisoned with these metals, 
produces a higher yield of coke and hydrogen at the expense of the more 
desirable gasolines and butanes. Examples of such poisoning may be found 
in U.S. Pat. No. 3,147,228 where the yield of desirable butanes, butylenes 
and gasoline dropped from about 59 to about 49 volume percent as the 
contamination of the catalyst with nickel and vanadium increased, from 55 
ppm to 645 ppm nickel and 145 ppm to 1480 ppm vanadium. Because many 
cracking units are limited by coke burning or gas handling facilities, 
increased coke or gas yields require a reduction in conversion or 
throughput to stay within the unit capacity. 
In FCCUs, the bulk of contaminant elements from the feedstock remain in the 
circulating catalyst system. Through the cycles of cracking, fresh 
catalyst deactivation is caused by contaminant blockage of active sites by 
metals, including nickel, vanadium, copper and iron. Deactivation may also 
occur as the result of steam catalyzed by contaminants such as vanadium 
and sodium. To compensate for decreased FCC feedstock conversion and 
product selectivity, a portion of the circulating equilibrium catalyst is 
regularly withdrawn and replaced by fresh catalyst added to the system. 
This withdrawn or spent catalyst contaminated with various metals must 
then be properly disposed of. 
Both because of the expense involved in replacing spent catalyst with fresh 
catalyst and because of the expense involved with the environmentally safe 
disposal of metal-contaminated catalyst, there have been many efforts to 
demetallize and reuse the contaminated catalyst. In conventional 
demetallization processes, portions of the metal contaminants are removed 
from the spent FCC catalyst by pyrometallurgical methods, e.g., calcining, 
sulfiding, nitrogen stripping and chlorinating, followed by 
hydrometallurgical methods, e.g., leaching, washing and drying, to produce 
a demetallized spent catalyst for reuse in the FCCU. Such a 
demetallization (DEMET) process is described in U.S. Pat. No. 4,686,197, 
incorporated herein by reference. The '197 patent describes an improved 
demetallization process. Also referenced are prior demetallization 
processes which include the chlorination at elevated temperatures of 
alumina, silica alumina and silica catalysts contaminated with metals. 
See, for example, U.S. Pat. Nos. 3,150,104; 3,122,510; 3,219,586; and 
3,182,025. Also referenced are demetallization processes which do not 
primarily involve chlorination of the catalyst. See, for example, U.S. 
Pat. Nos. 4,101,444; 4,163,709; 4,163,710; and 4,243,550. 
Prior demetallization processes, such as the DEMET process described in the 
'197 patent have most frequently employed calcining and sulfiding steps 
performed at about 787.degree. C. followed by chlorination at 343.degree. 
C. The offgases from the reactor are scrubbed, while the removed 
contaminant metals are precipitated and filtered for disposal in the same 
manner used for spent catalyst or disposed through any acceptable Best 
Demonstrated Available Technology (BDAT) method for the recycling of 
metals. 
The recycling of demetallized spent FCC catalyst has reduced the 
requirements for fresh catalyst additions, reduced the generation of 
catalyst fines and reduced the disposal problem of spent catalyst. 
Conventional demetallization processes remove contaminants known to be 
detrimental to conversion, to product selectivity and to the mechanical 
performance of the FCC. 
While the DEMET process based upon the '197 patent and the prior processes 
described therein have provided methods for demetallization of spent FCC 
catalyst, those methods have not been entirely or universally acceptable. 
Operating conditions are severe and must be strictly maintained. 
Therefore, the process has found only limited use. For these and other 
reasons, there has been a long felt but unfulfilled need for a more 
economical, more efficient, easier and safer method for demetallizing FCC 
catalysts and for enhancing the acid sites thereon. The present invention 
solves those needs. 
SUMMARY OF THE INVENTION 
The present invention is directed to processes for enhancing the acid sites 
of fluid catalytic cracking (FCC) catalysts. More particularly, the 
invention is directed to aqueous processes for treating either spent or 
fresh FCC catalysts to enhance the acid sites, thus improving the catalyst 
reactivity and selectivity. 
In the processes of the present invention, spent or fresh FCC catalyst is 
added to an aqueous solution to produce an aqueous slurry. The aqueous 
solution comprises water, phosphorus, aluminum and optionally sulfurous or 
sulfuric acid. The phosphorus is provided by phosphorus acid, phosphoric 
acid or ammonium hydrogen phosphate. The aluminum is provided from an 
aluminum source selected from the group consisting of aluminum 
trihydroxide, alumina trihydrate, gibbsite and aluminum oxide and is 
characterized by a low level of chloride contamination. In fact, chloride 
contamination of the aluminum source should be not more than about 1000 
ppm; preferably the aluminum source should have less than about 200 ppm 
chloride. 
The aqueous solution preferably comprises equal concentrations of 
phosphorus and aluminum where each is present in the range of about 
0.1-3.0 percent-by-weight, preferably in the range of about 0.2-1.5 
percent-by-weight, more preferably about 0.7-1.0 percent-by-weight, with 
respect to the solution. If present, the sulfurous or sulfuric acid should 
also be present at the same concentration. The pH of the solution should 
be in the range of about 3.0 to 12.0, preferably from about 3.25 to about 
5.0, and is adjusted by the addition of sufficient quantity of ammonium 
hydroxide or ammonium sulfate to achieve the desired pH. 
While the process is intended for the treatment of spent FCC catalyst, it 
has been found that fresh catalyst will also benefit from the process. The 
FCC catalyst is added to the aqueous solution in a weight ratio of about 1 
part catalyst to 1-10 parts water, preferably in a ratio of about 1 part 
catalyst to about 4-10 parts water. In order to produce the desired 
aqueous slurry, catalyst is typically added to the aqueous solution with 
stirring. 
The reaction proceeds quickly. Stirring of the slurry should be continued 
until the pH stabilizes. Upon stabilization of the pH, the enhanced 
catalyst is separated from the slurry. While washing is not necessary, it 
may be desirable to wash the separated catalyst with successive aliquots 
of wash water until the eluted wash water aliquot contains less than about 
100 ppm chloride. 
FCC catalysts, whether spent or fresh, treated by the forgoing process have 
been found to provide improved reactivity and selectivity, apparently as 
the result of added or enhanced acid sites made available for reaction on 
the catalyst surface. These improvements have been achieved without 
requiring the severe and expensive pyrometallurgical steps of conventional 
demetallization processes. However, the aqueous processes of the present 
invention may also be used to treat spent FCC catalysts which have 
previously been demetallized by conventional pyrometallurgical and/or 
hydrometallurgical processes. Thus, the long felt, but unfulfilled need 
for a more efficient demetallization process has been met. 
The processes of the present invention produce improved catalysts 
exhibiting higher activity and higher stability than catalysts produced by 
prior processes. The catalysts produced by the present processes are more 
resistant to deactivation and show improved stability. Thus, the 
production of coke and hydrogen are both minimized and the throughput of 
the catalytic cracker can be increased. These and other meritorious 
features and advantages of the present invention will be more fully 
appreciated from the following detailed description and claims.

While the invention will be described in connection with the presently 
preferred embodiments, it will be understood that it is not intended to 
limit the invention to those embodiments. On the contrary, it is intended 
to cover all alternatives, modifications and equivalents as may be 
included in the spirit of the invention as defined in the appended claims. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention provides improved methods for enhancing the acid 
sites of fluid catalytic cracking (FCC) catalysts, particularly spent 
catalysts. In the methods of the present invention, the FCC catalyst is 
treated in an aqueous solution including sources of both phosphorus and 
aluminum having less than about 1000 ppm chloride as a trace element under 
specified conditions. 
In the methods of the present invention, an aqueous solution comprising 
water, about 0.1-3.0 percent-by-weight phosphoric acid, about 0.1-3.0 
percent-by-weight aluminum and optionally about 0.1-3.0 percent-by-weight 
sulfurous acid is prepared. Preferably the solution comprises about 
0.2-1.5 percent-by-weight phosphorus and aluminum. More preferably both 
the phosphorus and aluminum are present in a concentration of about 
0.7-1.0 percent-by-weight, most preferably at about 8000 ppm. The 
sulfurous or sulfuric acid optionally included is preferably at the same 
concentration as the phosphorus and aluminum. 
The phosphorus source is preferably selected from the group consisting of 
phosphorous acid, phosphoric acid and ammonium dihydrogen phosphate and 
most preferably, comprises phosphoric acid. The aluminum is provided by an 
aluminum source selected from the group consisting of the aluminum 
trihydrates and aluminum oxides and, further, should be characterized by a 
low chloride level, preferably less than about 1000 ppm chloride as a 
trace constituent. The aluminum trihydrates include gibbsite alumina, 
boehmite alumina, bayerite alumina, diaspore alumina and derivatives 
thereof. The preferred aluminum source is alumina trihydrate, most 
preferably gibbsite alumina, and contains less than about 200 ppm chloride 
as a trace constituent. 
In the process of the present invention, the pH of the aqueous solution of 
acid and aluminum is adjusted to about 3-12, most preferably to about 
3.25-5.0 by the addition of ammonium hydroxide. While it is preferred that 
the pH be adjusted before the addition of catalyst to the solution, in an 
alternative method the catalyst may be added before the pH adjustment. 
The FCC catalyst is added to the pH adjusted aqueous solution in a weight 
ratio of about one part catalyst to about 1-10 parts water to produce an 
aqueous slurry. In the more preferred methods of the present invention, 
the ratio of catalyst to water is about 1 part catalyst to about 4-10 
parts water. 
While it has been found that the acid sites of fresh catalyst may be 
improved by the methods of the present invention, the present invention is 
particularly useful for the processing of spent catalyst. In fact, the 
processes of the present invention have been found most useful for the 
processing of spent catalysts heavily contaminated by nickel. While it is 
not necessary to treat a spent catalyst by conventional pyrometallurgical 
or hydrometallurgical demetallization processes, e.g., by processes such 
as those disclosed in U.S. Pat. No. 4,686,197 which is incorporated herein 
by reference, the present methods may be used to further enhance the acid 
sites of spent catalysts which have been so treated. 
After the addition of catalyst to the pH adjusted aqueous solution, the 
resulting slurry should be stirred or otherwise mixed for a time 
sufficient for the pH of the solution to stabilize. Stabilization will 
typically occur in a pH range of about 3.25 to 5.0. The pH may be 
monitored by any conventional means, e.g., a standard pH probe. 
Stabilization of the pH typically occurs after stirring for a time of 
about 1-10 minutes, commonly about 3-5 minutes. It has been found that 
additional stirring after stabilization of the pH provides no significant 
additional improvement in the results achieved. 
After the pH of the aqueous slurry has stabilized, the treated catalyst may 
be separated from the aqueous solution by any conventional means, e.g., 
filtration. Washing of the filtered catalyst has been found to be 
unnecessary. However, if washing is desired, the filtered catalyst may be 
washed with water, preferably until the eluted wash water shows less than 
about 100 ppm chloride. 
The foregoing method significantly enhances the acid sites of FCC 
catalysts. FCC catalysts, whether spent or fresh, treated in accord with 
the foregoing procedure show higher activity and higher stability than 
untreated catalysts or spent catalysts treated by prior processes. The 
foregoing method will now be described in connection with several specific 
examples. The following specific examples illustrate the methods of the 
foregoing process and provide illustrative examples of the improved 
results achieved therewith. 
Catalyst Treatment Procedure 
EXAMPLE 1 
An aqueous solution containing phosphoric acid and aluminum was prepared by 
adding to a clean beaker 2400 ml of water and a stirring bar. With 
constant stirring, 13 ml of phosphoric acid (99.99 percent acid) and 21 
grams of aluminum trihydroxide were added. The resulting aqueous solution 
was stirred for five minutes or until the aluminum was dissolved. The pH 
of the solution was raised to about 5.0 by the addition of ammonium 
hydroxide while continuing to stir. To the pH adjusted solution was added 
300 grams of catalyst with continuous stirring to produce an aqueous 
slurry. The pH of the aqueous slurry was monitored and, upon stabilization 
of the pH, the slurry was filtered to separate the treated catalyst from 
the aqueous solution. The filtered, treated catalyst was washed with two 
successive washes, each comprising about 1200 ml of water. 
EXAMPLE 2 
The procedure of Example 1 was repeated with the exception that 13 ml 
phosphorous acid (99.99 percent acid) was substituted for the phosphoric 
acid. 
EXAMPLE 3 
The procedure of Example 1 was repeated except that 25 grams ammonium 
dihydrogen phosphate was substituted for the phosphoric acid. 
EXAMPLE 4 
The procedure of Example 1 was repeated except that the solution containing 
phosphorus and aluminum also included 324 ml of sulfurous acid (6 percent 
acid). 
EXAMPLE 5 
Example 1 was repeated except that the amount of phosphorus was doubled. 
EXAMPLE 6 
Example 1 was repeated except that the amount of aluminum as doubled. 
EXAMPLE 7 
Example 1 was repeated except that the amount of both phosphorus and 
aluminum were doubled. 
A variety of catalysts have been treated with the foregoing processes. 
Those catalysts included a fresh catalyst (FCAT) and equilibrium spent 
catalyst (ECAT) from several different sources. These treated catalysts, 
along with comparisons of untreated fresh and spent catalyst and catalyst 
treated by conventional DEMET procedures (DCAT) were tested to predict 
performance. 
Test Methods 
The expected performance of catalysts treated by the foregoing procedure 
have been determined using conventional micro activity testing (MAT) and 
steaming conditions which are known and used by those of skill in the art 
to test fresh, spent and demetallized catalysts. In these procedures, 
catalyst was treated with 100 percent steam at a temperature of about 
787.degree. C. (1450.degree. F.). A comparison of the results before 
steaming and after 4 hours of steaming provides an indication of the 
hydrothermal stability of the catalyst. In addition to those conventional 
steaming results, Applicant has employed a more rigorous test by 
continuing to steam the catalyst for 16 hours. Alternative tests which 
could be used for the same determination include fixed fluid bed, FCCU 
pilot plant, modified MAT and cyclic deactivation testing. 
It has been found that a catalyst which can survive the severity of 
temperature, steam and time in the foregoing MAT test would be expected to 
perform relatively the same in cyclic deactivation or pilot plant testing. 
Accordingly, in order to provide an indication of catalyst stability, 
conventional steaming and MAT tests including both 4 hour and 16 hour 
steaming conditions, have been performed on catalysts treated by the 
foregoing procedure. For comparison, the same tests were performed on 
untreated fresh and equilibrium spent catalysts and on spent catalyst 
treated with conventional DEMET methods. 
Full yield MAT tests were conducted on a variety of fresh and equilibrium 
catalysts and on catalysts (either fresh or equilibrium) treated in accord 
with the present invention. Tests were conducted prior to steaming and 
after steaming for 4 and 16 hours with 100 percent steam at 787.degree. C. 
(1450.degree. F.). Catalysts having a range of metal contamination were 
employed. Illustrative of that contamination is the concentration of 
nickel and vanadium in the equilibrium catalysts which ranged from 2500 
ppm to 1.6 percent as illustrated in Table 1. 
TABLE 1 
______________________________________ 
Metal Content (ppm) 
Catalyst Nickel Vanadium Ni + V 
______________________________________ 
E 510 1990 2500 
A 7350 797 8147 
G 4620 5220 9840 
C 15550 445 15995 
______________________________________ 
These tests provide ample data to make an accurate determination of the 
resistance to hydrothermal deactivation exhibited by fresh, spent and 
treated catalyst. The MAT results at constant conditions discussed below 
and illustrated in the accompanying figures and tables show the 
improvement in catalyst performance achieved by treatment of these 
catalysts with the methods of the present invention. 
Significantly improved conversion is observed when using the methods of the 
present invention with equilibrium catalysts characterized by a wide range 
of metal contamination levels. FIGS. 1-4 illustrate the improved 
conversion achieved when catalysts E, A, G and C of Table 1 (initially 
contaminated with levels of nickel and vanadium ranging from 0.25-1.60 
percent-by-weight) are treated with the methods of the present invention. 
After steaming for 16 hours, the treated catalysts showed significantly 
improved total conversion rates with improvements of about 8-18 percent 
absolute as compared to the total conversion rates for the untreated 
equilibrium catalysts. 
FIGS. 5-13 further illustrate the improvements achieved using illustrative 
equilibrium catalyst A (having a combined nickel and vanadium content of 
about 0.8 percent) treated in accord with the present invention. The 
figures compare the results achieved with untreated equilibrium catalyst A 
and with equilibrium catalyst A treated in accord with the present 
invention without steaming and after steaming for 4 and 16 hours as stated 
above. Selectivity for gasoline, coke and dry gas are all improved. FIG. 5 
illustrates the increased conversion to gasoline achieved. FIGS. 6 and 7 
illustrate the desirable reduction in the production of both coke and gas. 
FIGS. 8-10 illustrate results after 0, 4 and 16 hours of steaming for 
treated and untreated equilibrium catalyst A. FIGS. 8 and 9 illustrate, 
respectively, improvements in the conversion to liquified petroleum gas 
(lpg) and light crude oil (LCO). With higher conversion, the LPG content 
is almost doubled after steaming for 16 hours while the LCO level remains 
nearly constant. FIG. 10 illustrates the desirable reduction in the 
conversion to heavy crude oil (HCO). With higher total conversion, the 
production of HCO is reduced by almost half after steaming for 16 hours. 
FIG. 11 illustrates significant reduction in the production of heavy crude 
oil (HCO) with little increase in coke content when comparing untreated 
equilibrium catalyst A with the same catalyst treated in accord with the 
present invention. As can be seen, conversion to HCO is reduced almost by 
half through use of the present invention. FIG. 12 illustrates the 
beneficial increase in the ratio of light to heavy crude oil (LCO/HCO) 
achieved by use of the present invention. Finally, FIG. 13 illustrates the 
increased production of the most desirable products, i.e., liquified 
petroleum gas, gasoline and light crude oil by use of the present 
invention. 
In summary, FIGS. 5-13 illustrate increased conversion and production of 
desirable end products with reduced production of undesirable products 
achieved with an equilibrium catalyst treated in accord with the methods 
of the present invention. Further, these figures illustrate consistent 
improvement found not only initially, but after steaming at 4 and 16 
hours, thus indicating the improved hydrothermal stability which can be 
expected from these treated catalysts. 
The improvements achieved using the methods of the present invention 
outlined in Example 1-7 above with the catalysts listed in Table 1 are 
illustrated in the following tables and comments. 
Catalyst E characterized by low nickel and vanadium contamination (510 ppm 
Ni and 1990 ppm V) was used in a series of experiments. MAT tests were 
performed prior to steaming and after steaming at 4 and 16 hours with 100 
percent steam at 787.degree. C. (1450.degree. F.) as discussed above. 
Tests were performed on the untreated equilibrium catalysts, on 
equilibrium catalysts treated by standard demetallization or by the 
methods of the present invention. The following tables present for 
comparison purposes the rate of conversion, together with the percentage 
production of dry gas, liquified petroleum gas (LPG), gasoline, light 
crude oil (LCO), slurry and coke. The results observed with untreated 
equilibrium catalyst E are summarized in Table 2. The results observed 
using equilibrium catalyst E subjected to a conventional demetallization 
technique are summarized in Table 3. Table 4 illustrates the results 
achieved by treating equilibrium catalyst E in accord with the methods of 
the present invention as set forth in Example 1 above. Finally, Table 5 
illustrates the results achieved by treatment of equilibrium catalyst E by 
the method set forth in Example 2 above, preceded by a conventional 
demetallization treatment. 
TABLE 2 
______________________________________ 
Steaming at 1450.degree. F. 
(Hours) 
ECAT E 0 4 16 
______________________________________ 
Conversion (%) 
71.4 69.5 58.2 
Dry Gas (%) 2.5 3.0 2.3 
LPG (%) 17.5 14.7 13.2 
Gasoline (%) 
43.8 44.5 37.5 
LCO (%) 16.9 18.0 20.1 
Slurry (%) 11.7 12.5 21.8 
Coke (%) 7.6 7.3 5.2 
______________________________________ 
TABLE 3 
______________________________________ 
Steaming at 1450.degree. F. 
(Hours) 
DEMET 0 4 16 
______________________________________ 
Conversion (%) 
74.0 70.3 66.5 
Dry Gas (%) 2.3 2.0 1.7 
LPG (%) 20.2 16.5 16.6 
Gasoline (%) 
44.3 48.2 45.5 
LCO (%) 14.5 17.3 17.6 
Slurry (%) 11.5 12.4 16.0 
Coke (%) 7.2 3.5 2.7 
______________________________________ 
TABLE 4 
______________________________________ 
Steaming at 1450.degree. F. 
(Hours) 
Example 1 0 4 16 
______________________________________ 
Conversion (%) 
70.6 69.9 60.3 
Dry Gas (%) 3.0 2.5 2.2 
LPG (%) 17.0 13.1 8.8 
Gasoline (%) 
45.3 48.1 45.9 
LCO (%) 15.8 17.1 19.9 
Slurry (%) 13.6 13.0 19.9 
Coke (%) 5.3 6.2 3.3 
______________________________________ 
TABLE 5 
______________________________________ 
Steaming at 1450.degree. F. 
(Hours) 
DEMET before 
Example 2 0 4 16 
______________________________________ 
Conversion (%) 
75.6 68.1 63.1 
Dry Gas (%) 2.4 1.6 1.5 
LPG (%) 19.2 14.2 12.3 
Gasoline (%) 
46.4 50.3 47.3 
LCO (%) 14.8 17.7 18.0 
Slurry (%) 9.6 14.2 18.9 
Coke (%) 7.6 1.9 2.0 
______________________________________ 
The above tables illustrate the significant improvement in total conversion 
observed with equilibrium catalyst treated in accord with the methods of 
the present invention. They also illustrate that the production of 
desirable products, e.g., gasoline, have been improved, while achieving a 
reduction in undesirable products, e.g., coke. 
To illustrate the improvements achieved using the methods of the present 
invention as set forth in Examples 1-7 above, another series of tests were 
performed using equilibrium catalyst A from Table 1 having an average 
nickel and vanadium contamination of about 0.8 percent (7350 ppm Ni and 
797 ppm V). In one instance, the equilibrium catalyst was calcined at 
843.degree. C. (1550.degree. F.) for 4 hours and in another treated with a 
conventional demetallization process prior to treatment with the method of 
the present invention set forth in Example 1 above. Finally, it was seen 
that improved results were obtained by treating fresh catalyst with the 
method of the present invention. The results of these various treatments 
of catalyst A are illustrated in Tables 6-15. 
TABLE 6 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
ECAT A 0 4 16 
______________________________________ 
Conversion (%) 
56.8 46.9 37.9 
Dry Gas (%) 1.7 1.9 1.9 
LPG (%) 12.8 9.4 6.9 
Gasoline (%) 
35.7 31.2 25.0 
LCO (%) 21.6 22.6 20.4 
Slurry (%) 21.6 30.5 41.7 
Coke (%) 6.6 4.4 4.1 
______________________________________ 
TABLE 7 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Example 1 0 4 16 
______________________________________ 
Conversion (%) 
73.3 65.2 56.2 
Dry Gas (%) 3.0 3.2 2.2 
LPG (%) 18.7 15.9 11.7 
Gasoline (%) 
40.1 40.7 38.0 
LCO (%) 13.4 16.7 17.5 
Slurry (%) 13.4 18.1 26.3 
Coke (%) 11.4 5.5 4.3 
______________________________________ 
TABLE 8 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Calcine before 
Example 1 0 4 16 
______________________________________ 
Conversion (%) 
74.8 68.5 60.4 
Dry Gas (%) 3.1 2.3 1.9 
LPG (%) 20.8 15.8 12.4 
Gasoiine (%) 
45.2 47.4 44.2 
LCO (%) 14.3 16.1 17.7 
Slurry (%) 10.9 15.4 21.9 
Coke (%) 5.8 3.0 1.9 
______________________________________ 
TABLE 9 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
DEMET before 
Example 1 0 4 16 
______________________________________ 
Conversion (%) 
69.1 69.2 61.0 
Dry Gas (%) 3.3 2.6 1.8 
LPG (%) 16.0 15.3 13.4 
Gasoline (%) 
42.6 47.6 44.7 
LCO (%) 14.7 15.0 16.6 
Slurry (%) 16.2 15.8 22.4 
Coke (%) 7.1 3.7 1.1 
______________________________________ 
Tables 6-9 illustrate the improved conversion and improved production of 
desirable products, most notably LPG and gasoline, observed with the 
methods of the present invention. Table 6 illustrates conversion and MAT 
results using untreated equilibrium catalyst A. The improved results 
obtained upon treatment of the catalyst with the method Example 1 is 
illustrated in Table 7. Tables 8 and 9, respectively, illustrate the 
further improvement achieved when the method of Example 1 is practiced 
after, respectively, calcining the sample at 843.degree. C. (1550.degree. 
F.) for 4 hours or after conventional demetallization. Not only has total 
conversion been increased, but the desirable LPG and gasoline fractions 
have been significantly increased, while the undesirable slurry and coke 
products have been significantly reduced. 
The results achieved using equilibrium catalyst A treated in accord with 
the procedures set forth in Examples 3-7 above are illustrated in Tables 
10-14. 
TABLE 10 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Example 3 0 4 16 
______________________________________ 
Conversion (%) 
73.9 65.0 59.8 
Dry Gas (%) 3.4 2.4 2.1 
LPG (%) 20.8 15.7 13.6 
Gasoline (%) 
41.3 44.2 42.0 
LCO (%) 13.3 15.2 15.5 
Slurry (%) 12.9 19.8 24.6 
Coke (%) 8.3 2.7 2.1 
______________________________________ 
TABLE 11 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Example 4 0 4 16 
______________________________________ 
Conversion (%) 
67.4 54.2 44.6 
Dry Gas (%) 2.4 1.7 1.4 
LPG (%) 18.4 12.9 9.2 
Gasoline (%) 
38.2 36.3 31.9 
LCO (%) 13.7 15.3 15.9 
Slurry (%) 19.0 30.5 39.5 
Coke (%) 8.4 3.3 2.1 
______________________________________ 
TABLE 12 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Examples 0 4 16 
______________________________________ 
Conversion (%) 
66.2 63.5 55.6 
Dry Gas (%) 2.0 1.7 1.5 
LPG (%) 16.4 16.1 13.6 
Gasoline (%) 
40.4 42.2 38.1 
LCO (%) 12.6 14.9 15.9 
Slurry (%) 21.2 21.6 28.5 
Coke (%) 7.4 3.6 2.4 
______________________________________ 
TABLE 13 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Example 6 0 4 16 
______________________________________ 
Conversion (%) 
70.5 61.0 47.9 
Dry Gas (%) 2.4 1.4 1.5 
LPG (%) 18.2 12.1 11.8 
Gasoline (%) 
41.1 43.1 32.9 
LCO (%) 14.6 16.7 16.0 
Slurry (%) 14.9 22.3 36.2 
Coke (%) 8.8 4.4 1.6 
______________________________________ 
TABLE 14 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Example 7 0 4 16 
______________________________________ 
Conversion (%) 
71.2 62.6 45.9 
Dry Gas (%) 2.2 2.3 1.2 
LPG (%) 19.9 17.7 9.8 
Gasoline (%) 
39.4 39.0 33.5 
LCO (%) 13.9 14.5 15.9 
Slurry (%) 14.9 22.9 38.1 
Coke (%) 9.7 3.5 1.5 
______________________________________ 
Again, it is seen that total conversion has been improved with catalyst 
treated by each of the procedures of Examples 3-7 above, both initially 
and after steaming. Further, the production of desirable products, e.g., 
LPG and gasoline, is increased, while the production of coke is 
significantly reduced. 
Finally, Table 15 below illustrates the improved hydrothermal stability and 
conversion imparted to fresh catalyst A when treated by the methods of the 
present invention, specifically using the method set forth in Example 2 
above. After steaming at 16 hours, the total conversion rate remains above 
70 percent with almost 50 percent conversion to gasoline. In fact, 
conversion to dry gas, LPG and gasoline exceeds 70 percent with less than 
2 percent coke. 
TABLE 15 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Example 2 (FRESH) 
0 4 16 
______________________________________ 
Conversion (%) 
85.7 78.7 71.9 
Dry Gas (%) 5.4 3.3 2.2 
LPG (%) 28.2 23.8 19.0 
Gasoline (%) 43.8 48.1 49.0 
LCO (%) 9.5 13.8 16.9 
Slurry (%) 4.8 7.6 11.3 
Coke (%) 8.4 3.5 1.6 
______________________________________ 
Table 16-18 illustrate the results of similar treatments and tests using a 
catalyst contaminated with about 1 percent nickel and vanadium (4620 ppm 
Ni and 5220 ppm Vanadium) and comprising catalyst G in Table 1. 
TABLE 16 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
ECAT G 0 4 16 
______________________________________ 
Conversion (%) 
56.8 43.8 35.3 
Dry Gas (%) 2.6 2.4 2.1 
LPG (%) 13.4 8.4 5.0 
Gasoline (%) 
35.3 26.0 19.4 
LCO (%) 22.9 22.1 19.0 
Slurry (%) 20.3 34.1 45.7 
Coke (%) 5.5 6.9 8.9 
______________________________________ 
TABLE 17 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Example 1 0 4 16 
______________________________________ 
Conversion (%) 
63.2 55.7 41.2 
Dry Gas (%) 2.7 2.6 2.6 
LPG (%) 15.5 11.5 6.9 
Gasoline (%) 
39.0 38.4 29.2 
LCO (%) 14.7 17.7 19.3 
Slurry (%) 22.1 26.6 39.5 
Coke (%) 6.2 3.2 2.6 
______________________________________ 
TABLE 18 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Calcine before 
Example 1 0 4 16 
______________________________________ 
Conversion (%) 
72.2 62.5 52.2 
Dry Gas (%) 2.9 2.4 2.0 
LPG (%) 18.9 13.8 10.0 
Gasoline (%) 
39.0 41.1 37.2 
LCO (%) 13.6 16.5 18.1 
Slurry (%) 14.2 21.0 29.7 
Coke (%) 11.3 5.2 2.9 
______________________________________ 
TABLE 19 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
DEMET before 
Example 5 0 4 16 
______________________________________ 
Conversion (%) 
72.3 58.8 44.8 
Dry Gas (%) 2.3 2.0 1.9 
LPG (%) 19.5 13.5 8.3 
Gasoline (%) 
44.8 40.2 32.2 
LCO (%) 13.6 16.5 18.1 
Slurry (%) 14.1 24.7 37.1 
Coke (%) 5.8 3.1 2.4 
______________________________________ 
The results obtained using equilibrium catalyst G in Table 16 may be 
compared with those for the same catalyst treated in accord with the 
present invention in Tables 17-19. In Table 17, the catalyst has been 
treated in accord with the method set forth in Example 1 above. In Table 
18, the catalyst was calcined before treatment by the method of Example 1. 
Finally, in Table 19, the catalyst was subjected to a conventional 
demetallization process prior to treatment by the method of Example 5. In 
all instances, it is seen that the total conversion, both initially and 
after steaming, has been significantly improved. Further, the conversion 
to desirable products, e.g., gasoline and LPG, has been increased while 
the conversion to less desirable products, e.g., slurry and coke, have 
been reduced. In fact, production of coke has been reduced by more than 
two-thirds while production of gasoline has been increased by more than 
half. 
The effect of treatment by the methods of the present invention on 
equilibrium catalyst C of Table 1 contaminated with about 1.6 percent 
nickel and vanadium (15,550 ppm Ni and 445 ppm V) has been investigated 
and the results reported below in Tables 20-23. 
TABLE 20 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
ECAT C 0 4 16 
______________________________________ 
Conversion (%) 
62.3 50.2 46.5 
Dry Gas (%) 1.8 1.7 1.4 
LPG (%) 13.4 7.1 7.8 
Gasoline (%) 
38.2 34.5 33.1 
LCO (%) 16.7 17.8 19.0 
Slurry (%) 21.0 32.0 34.5 
Coke (%) 8.9 6.9 4.2 
______________________________________ 
TABLE 21 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Example 1 0 4 16 
______________________________________ 
Conversion (%) 
71.6 66.1 60.2 
Dry Gas (%) 2.7 2.2 2.3 
LPG (%) 17.4 15.0 13.7 
Gasoline (%) 
42.0 44.6 40.8 
LCO (%) 15.0 16.6 17.1 
Slurry (%) 13.4 17.3 22.7 
Coke (%) 9.5 4.3 3.4 
______________________________________ 
TABLE 22 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
DEMET before 
Example 1 0 4 16 
______________________________________ 
Conversion (%) 
77.5 70.3 57.9 
Dry Gas (%) 3.4 2.4 2.4 
LPG (%) 25.3 22.6 16.0 
Gasoline (%) 
38.3 42.1 36.7 
LCO (%) 12.5 14.7 16.1 
Slurry (%) 10.0 14.9 26.0 
Coke (%) 10.6 3.2 2.9 
______________________________________ 
TABLE 23 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Example 5 0 4 16 
______________________________________ 
Conversion (%) 
70.1 60.5 58.0 
Dry Gas (%) 2.8 1.8 2.4 
LPG (%) 16.7 15.1 13.4 
Gasoline (%) 
39.2 39.6 39.6 
LCO (%) 13.7 16.4 16.1 
Slurry (%) 16.2 23.1 25.8 
Coke (%) 11.5 4.1 2.6 
______________________________________ 
Table 20 summarizes the MAT results obtained following testing of untreated 
equilibrium catalyst C. Compare those results with the results summarized 
in Tables 21-23 illustrating the same equilibrium catalyst treated in 
accord with the methods set forth in Example 1 or 5 above. It is readily 
seen that total conversion has been increased by the present invention 
along with increased production of the desirable fractions, e.g., LPG and 
gasoline, while production of less desirable coke and slurry has been 
reduced. 
Finally, Tables 24-26 illustrate results obtained using fresh catalyst C. 
Table 24 illustrating the results for untreated fresh catalyst C may be 
compared with the results below in Tables 25 and 26. Tables 25 and 26 
illustrate, respectively, fresh catalyst A treated in accord with the 
methods of the present invention set forth in Example 1 either alone or 
with prior conventional demetallization. 
TABLE 24 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
FRESH C 0 4 16 
______________________________________ 
Conversion (%) 
87.7 65.8 57.4 
Dry Gas (%) 4.1 1.9 1.3 
LPG (%) 34.3 18.4 13.5 
Gasoline (%) 
26.7 42.5 40.7 
LCO (%) 4.9 20.1 20.5 
Slurry (%) 7.4 14.2 22.1 
Coke (%) 22.6 2.9 1.9 
______________________________________ 
TABLE 25 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
Example 1 
(Fresh) 0 4 16 
______________________________________ 
Conversion (%) 
87.8 76.6 70.7 
Dry Gas (%) 5.0 2.4 1.6 
LPG (%) 33.8 20.0 18.1 
Gasoline (%) 
21.1 48.8 49.1 
LCO (%) 3.2 13.6 15.0 
Slurry (%) 9.0 9.8 14.2 
Coke (%) 27.9 5.4 1.9 
______________________________________ 
TABLE 26 
______________________________________ 
Steaming at 1450.degree. F. (Hours) 
DEMET before 
Example 1 0 4 16 
______________________________________ 
Conversion (%) 
93.8 75.0 67.8 
Dry Gas (%) 6.2 3.8 1.3 
LPG (%) 34.9 21.4 16.5 
Gasoline (%) 
26.7 45.3 47.6 
LCO (%) 3.8 13.6 16.5 
Slurry (%) 2.4 11.4 15.7 
Coke (%) 26.0 4.4 2.5 
______________________________________ 
It is readily apparent that the methods of the present invention produce 
improvements to the fresh catalyst similar to those seen previously with 
the equilibrium catalysts. Total conversion has been increased along with 
production of the desirable gasoline and LPG fractions. Conversion to 
light crude oil and slurry have been reduced, while producing no 
significant change in coke. 
In summary, the processes of the present invention have been shown to 
recover significantly higher percentages of the maximum possible activity 
compared to recovery with conventional demetallization processes. The 
combination of low deactivation rates and higher MAT conversions suggest 
that catalysts treated in accord with the present invention will be 
superior to those recovered by standard demetallization techniques in 
commercial applications. Thus, lower quantities of fresh catalyst will be 
required to maintain FCC unit activity and throughput. 
The foregoing description has been directed in primary part to a particular 
preferred embodiment in accordance with the requirements of the Patent 
Statutes and for purpose of explanation and illustration. It will be 
apparently, however, to those skilled in the art that many modifications 
and changes in the specifically described methods may be made without 
departing from the true spirit and scope of the invention. For example, 
the order of steps in the method may be adjusted. For example, while it is 
preferred that the pH of the aqueous solution be adjusted before addition 
of catalyst, it is has been found that acceptable results may be achieved 
by adding catalyst to the aqueous solution prior to the adjustment of the 
pH by the addition of ammonium hydroxide. Therefore, the invention is not 
restricted to the preferred embodiment described and illustrated, but 
covers all modifications which may fall within the scope of the following 
claims.