A spent metal contaminated zeolite-containing catalytic cracking catalyst composition is reactivated by a process which comprises contacting with an aqueous solution of HC1 and/or HNO.sub.3 and/or H.sub.2 SO.sub.4. The thus reactivated catalyst composition can be employed in a catalytic cracking process.

BACKGROUND OF THE INVENTION 
This invention relates to a method of reactivating spent, 
metal-contaminated zeolite-containing catalytic cracking catalysts. In 
another aspect, this invention relates to a catalytic cracking process 
employing a reactivated spent catalytic cracking catalyst. 
Various methods of rejuvenating deactivated, metal-contaminated 
zeolite-containing catalytic cracking catalysts are known, such as 
treatment with ammonium compounds and fluorine compounds, described in 
U.S. Pat. No. 4,814,066. However, there is an ever present need to develop 
new, more effective and/or efficient catalyst reactivation processes. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a process for treating a 
spent, metal-contaminated zeolite-containing catalytic cracking catalyst 
composition under such conditions as to enhance its catalytic cracking 
activity and/or reduce its capability of generating hydrogen during 
catalytic cracking. It is another object of this invention to provide a 
reactivated zeolite-containing catalytic cracking catalyst composition. It 
is a further object of this invention to provide a catalytic cracking 
process employing a reactivated spent catalytic cracking catalyst 
composition. Other objects and advantages will become apparent from the 
detailed description of the invention and the appended claims. 
According to this invention, a catalyst reactivation process comprises the 
step of: 
(a) contacting a spent zeolite-containing catalytic cracking catalyst 
composition which contains at least one metal containment with a 
non-oxidizing acid solution consisting essentially of water and at least 
one inorganic acid selected from the group consisting of hydrochloric 
acid, nitric acid and sulfuric acid; 
(b) at least partially separating the acid-treated spent catalytic cracking 
catalyst composition obtained in step (a) from the aqueous solution used 
in step (a); and 
(c) drying the at least partially separated spent catalytic cracking 
catalyst composition obtained in step (b) (i.e., to substantially remove 
water from the at least partially separated spent catalytic cracking 
catalyst composition); 
wherein said catalyst reactivation process is carried out under such 
conditions such as to obtain a reactivated cracking catalyst composition 
having higher catalytic cracking activity (as measured by enhanced feed 
conversion and/or higher gasoline yield attained during catalytic cracking 
of a hydrocarbon-containing oil) than said spent zeolite-containing 
catalytic cracking catalyst composition. 
In a preferred embodiment, the reactivation process of this invention 
comprises the additional step of treating the reactivated catalytic 
cracking catalyst composition obtained in the acid-treatment step 
described above with at least one antimony compound as metals passivating 
agent, under such conditions as to reduce the detrimental effect of the at 
least one metal contaminant (still contained in said reactivated catalytic 
cracking catalyst composition after the acid treatment step) during 
catalytic cracking, as measured by hydrogen generation in a test for 
catalytically cracking a heavy hydrocarbon-containing oil, carried out 
substantially in accordance with the procedure of Example II of U.S. Pat. 
No. 4,794,095. 
Further in accordance with this invention, a catalytic cracking process is 
provided comprising the step of contacting a hydrocarbon-containing feed 
stream with a zeolite-containing cracking catalyst composition, under such 
catalytic cracking conditions as to obtain at least one normally liquid 
(i.e., liquid at 25.degree. and 1 atm.) hydrocarbon-containing product 
stream having a lower initial boiling point and higher API gravity than 
said hydrocarbon-containing feed stream, wherein at least a portion of 
said zeolite-containing cracking catalyst composition is a reactivated 
catalytic cracking catalyst composition having been obtained by the 
reactivation process of this invention (described above).

DETAILED DESCRIPTION OF THE INVENTION 
The term "catalytic cracking", as used herein, implies that essentially no 
hydrocracking occurs and that the catalytic cracking process is carried 
out with a hydrocarbon-containing oil substantially in the absence of 
added hydrogen gas. The term "spent", as used herein, implies that at 
least a portion of the zeolite-containing catalyst composition employed in 
the reactivation process of this invention has previously been used in a 
process for catalytically cracking hydrocarbon-containing oils, in 
particular those containing metal (Ni, V, Cu) impurities, and has thereby 
lost some of its initial catalytic activity (i.e., its catalytic cracking 
activity before its use in the previous cracking process). The spent 
catalytic cracking catalyst composition has been regenerated by stripping 
of adhered oil from the catalyst (such as by steam-stripping) and 
subsequent heating in an oxidizing gas atmosphere (such as air) so as to 
burn off coke deposits on the spent catalyst composition, before the spent 
catalytic cracking catalyst composition is treated by the reactivation 
process of this invention comprising steps (a)-(c). 
Any spent zeolite-containing catalyst composition, which contains at least 
one metal contaminant and at least a portion of which has previously been 
used in a catalytic cracking process, can be used as starting material in 
the acid treatment step of the reactivation process of this invention. The 
spent catalyst composition can contain any portion of such regenerated 
catalyst composition, ranging from 100% to about 10 weight-% (i.e., 
containing 0% to about 90 weight-% fresh, unused zeolite-containing 
catalytic cracking catalyst composition). The term "spent catalyst 
composition" encompasses equilibrium cracking catalysts, which are 
commonly employed in commercial catalytic cracking operations and 
generally comprise a physical blend of regenerated used catalyst 
composition and fresh (unused) cracking catalyst composition. An 
equilibrium catalyst generally comprises a mixture of catalyst particles 
of various ages, i.e., a portion of the equilibrium catalyst particles has 
passed through a varying number of cracking and regeneration cycles, while 
a small portion of the equilibrium catalyst particles is fresh (unused) 
cracking catalyst composition. 
The zeolite component of the spent zeolite-containing catalytic cracking 
catalyst composition of this invention can be any natural or synthetic 
crystalline aluminosilicate zeolite which exhibits cracking activity. 
Non-limiting examples of such zeolites are faujasite, chabazite, 
mordenite, offretite, erionite, Zeolon, zeolite X, zeolite Y, zeolite L, 
zeolite ZSM-4, zeolite ZSM-5, zeolite ZSM-11, zeolite ZSM-12, zeolite 
ZSM-23, zeolite ZSM-35, zeolite ZSM-38, zeolite ZSM-48, and the like, and 
mixtures thereof. Additional examples of suitable zeolites are listed in 
U.S. Pat. No. 4,158,621. The term "zeolite", as used herein, includes 
zeolites which have been pretreated, such as those from which a portion of 
Al has been removed from the crystalline framework, and zeolites which 
have been ion-exchanged with rare earth metal or ammonium or by other 
conventional ion-exchange methods. The term "zeolite", as used herein, 
also includes essentially aluminum-free silica polymorphs, such as 
silicalite, chromia silicates, ferrosilicates, borosilicates, and the 
like, as disclosed in U.S. Pat. No. 4,556,749. 
Generally, the zeolite component of the spent cracking catalyst composition 
is dispersed in a suitable solid refractory inorganic matrix material, 
such as alumina, silica, silica-alumina (presently preferred), aluminum 
phosphate, magnesium oxide, mixtures of two or more of the above-listed 
materials, and the like. The preparation of such zeolite/matrix cracking 
catalyst compositions is well known and is not a critical feature of this 
invention. Generally, the surface area (measured by nitrogen adsorption, 
substantially in accordance with the BET method of Brunauer, Emmet and 
Teller) of the spent zeolite/matrix cracking catalyst composition used in 
step (a) is in the range of from about 100 to about 800 m.sup.2 /g. 
Generally, the weight ratio of zeolite to matrix material in the spent 
cracking catalyst composition is in the range of from about 1:20 to about 
1:1. 
The spent zeolite-containing cracking catalyst composition employed in the 
reactivation process of the invention contains metal compounds as 
contaminants (generally as oxides), such as compounds of Ni, V, Fe, and 
Cu, and the like, in particular Ni and V. Contaminants of each metal can 
generally be present in amounts ranging from traces (about 0.01 weight-%) 
to about 2.0 weight-% of each contaminant metal, expressed as metal oxide. 
These impurities in the spent cracking catalyst compositions have 
generally been absorbed from the oil feed in a previous cracking process. 
However, the origin of these metal impurities is not believed to be a 
critical feature of this invention. It is within the scope of this 
invention to use spent cracking catalysts from which at least a portion of 
contaminant metals (Ni, V, Cu) have been removed (e.g., by the 
demetallizing process of U.S. Pat. No. 4,686,197). 
The inorganic acid(s) employed in step (a) can be HCl, HNO.sub.3, H.sub.2 
SO.sub.4 and mixtures thereof. The aqueous acidic contacting solution 
generally contains one or more of the above-described acids at any 
effective concentration, preferably about 0.0001 to about 1.0 mol/l, more 
preferably about 0.001 to about 0.05 mol/l. If HNO.sub.3 and/or H.sub.2 
SO.sub.4 are employed, their concentrations are such that they do not act 
as oxidizing agents. The pH of the aqueous contacting solution generally 
is in the range of about 0 to about 3, preferably about 0.5-2.5. The 
aqueous acidic solution consists essentially of water and at least one of 
the above-cited acids, and does not contain any appreciable amounts of 
oxidizing agents or reducing agents or ammonium compounds (such as 
NH.sub.4 NO.sub.3, NH.sub.4 F, NH.sub.4 HF.sub.2, and the like), i.e., 
these agents/compounds are substantially absent from the acid solution. 
The contacting of the spent zeolite-containing catalyst composition and the 
aqueous solution containing at least one inorganic acid can be carried out 
in any suitable manner. It can be done as a batch process in a vessel, 
preferably with agitation. Or it can be done continuously, such as by 
passing the aqueous solution comprising at least one of the 
above-described acid through a column filled with a spent cracking 
catalyst composition. Any suitable time of contact between solution and 
spent cracking catalyst composition can be employed, generally from about 
0.05 to about 5 hours (preferably about 5-30 minutes). Any suitable 
temperature can be employed in this contacting step generally from about 
10.degree. C. to about 100.degree. C. (preferably about 
60.degree.-90.degree. C.), generally at ambient pressure (1 atm). 
Generally, the weight-ratio of the aqueous contacting solution to the 
spent cracking catalyst is in the range of from about 2:1 to about 100:1; 
preferably about 4:1 to about 20:1. 
The thus-reactivated catalyst composition is at least partially (preferably 
substantially) separated from the aqueous, acidic treating solution used 
in step (a). Any suitable separating means can be employed in this step. 
Non-limiting examples of suitable solid/liquid separation means are 
filtration, centrifugation, settling and subsequent draining or 
decantation of the liquid, and the like. 
Optionally, the at least partially separated acid-treated catalyst 
composition is washed with a suitable liquid (preferably water). 
Generally, the temperature of the wash liquid (preferably water) is about 
30.degree.-98.degree. C. This washing step may enhance the removal of 
contaminant metals (in particular vanadium) from the catalytic cracking 
catalyst composition. Preferred washing conditions can easily be 
determined by those skilled in the art. 
The at least partially separated treated catalyst composition is dried in 
step (c), so as to substantially remove adhered water therefrom. Any 
effective drying conditions can be employed. Preferred drying conditions 
comprise a temperature of about 80.degree.-200.degree. C., at atmospheric 
pressure conditions, and a drying time of about 0.2-10 hours. 
In a preferred embodiment, an additional metals passivating step (d) is 
carried out by treating the dried, acid-treated spent catalyst 
composition, obtained in step (c), with at least one antimony compound. 
The term "metals passivating", as used herein, implies that the 
detrimental effect of generating H.sub.2 during catalytic cracking caused 
by metal deposits (such as Ni, V and Cu) on a cracking catalyst 
composition has been mitigated. Non-limiting examples of suitable Sb 
compounds are described in various patents (e.g. U.S. Pat. Nos. 3,711,422, 
4,025,458, 4,190,552, 4,193,891 and 4,263,131). Preferred antimony 
components are antimony tris(0,0-dihydrocarbyl) phosphorodithioates, 
antimony oxides (more preferably Sb.sub.2 O.sub.5), antimony carboxylates, 
antimony mercaptides, antimony fluorides, and mixtures thereof. 
In this additional metals passivating step, the acid-treated spent cracking 
catalyst composition is contacted (generally impregnated or sprayed) with 
a solution or, alternatively, a dispersion of at least one of the 
above-described metals passivating compounds of antimony in a suitable 
liquid medium (such as water) so as to incorporate into the acid-treated 
spent catalyst composition of the antimony compound in the solution or 
dispersion can be applied (preferably about 0.01-0.5 mol/l Sb). Any 
suitable weight ratio of the metals passivating compound to the 
acid-treated spent cracking catalyst composition can be applied in this 
metals passivating step. Generally, this weight ratio is in the range of 
from about 0.00001:1 to about 0.5:1, preferably in the range of from about 
0.001:1 to about 0.02:1. Generally, this additional metals passivating 
step is carried out at any suitable temperature, preferably, at a 
temperature of about 10.degree. to about 95.degree. C. 
Preferably, the additional metals passivating step is followed by another 
drying step (preferably in air or an inert gas such as N.sub.2, for about 
0.2-10 hours, at a temperature of about 100.degree. to about 200.degree. 
C.). The drying step may be followed by an additional calcining step 
(preferably at a temperature of about 200.degree. to about 750.degree. C., 
for about 0.2-10 hours, in air or an inert gas such as N.sub.2). In the 
calcining step, the applied antimony compound is substantially converted 
to an oxidic form (e.g., Sb.sub.2 O.sub.3 and/or Sb.sub.2 O.sub.5). 
Any suitable effective total level of the metals passivating element in the 
acid-treated spent catalytic cracking catalyst composition can be 
attained. Generally, this level is in the range of from about 0.01 to 
about 5 weight-% Sb, based on the weight of the substantially dry 
material. Preferably, this level is about 0.02-2 weight-% Sb. 
The reactivated cracking catalyst composition obtained in the 
above-described reactivation process of this invention can be used in any 
catalytic cracking process, i.e., a process for catalytically cracking 
hydrocarbon-containing oil feedstocks, in any suitable cracking reactor 
(e.g., in a FCC reactor or in a Thermofor moving bed reactor), essentially 
in the absence of added hydrogen gas. The reactivated catalyst composition 
obtained in the above-described steps can be used alone or in admixture 
with fresh (unused) zeolite-containing catalyst composition in catalytic 
cracking processes. 
The hydrocarbon-containing feed stream for the catalytic cracking process 
of this invention can be any suitable feedstock. Generally the feed has an 
initial boiling point (ASTM D 1160) in excess of about 400.degree. F., 
preferably a boiling range of from about 400.degree. to about 1200.degree. 
F., more preferably a range of from about 500.degree. to about 
1100.degree. F., measured at atmospheric pressure conditions. The API 
gravity (measured at 60.degree. F.) generally is in the range of from 
about 5 to about 40, preferably from about 10 to about 35. Generally, 
these feedstocks contain Ramsbottom carbon residue (ASTM D 524; usually 
about 0.1-20 weight-%), sulfur (generally about 0.1-5 weight-% S), 
nitrogen (generally about 0.05-2 weight-% N), nickel (generally about 
0.05-30 ppm Ni, i.e., parts by weight of Ni per million parts by weight of 
feed), vanadium (generally about 0.1-50 ppm V) and copper (generally about 
0.01-30 ppm Cu). Non-limiting examples of suitable feedstocks are light 
gas oils, heavy gas oils, vacuum gas oils, cracker recycle oils (cycle 
oils), residua (such as distillation bottoms fractions), and hydrotreated 
residua (e.g., hydrotreated in the presence of Ni, Co, Mo-promoted alumina 
catalysts), liquid coal pyrolyzates, liquid products from extraction or 
pyrolysis of tar sand, shale oils, heavy fractions of shale oils, and the 
like. The presently most preferred feedstocks are heavy gas oils and 
hydrotreated residua. 
Any suitable reactor can be used for the catalytic cracking process of this 
invention. Generally, a fluidized-bed catalytic cracking (FCC) reactor 
(preferably containing one or more risers) or a moving-bed catalytic 
cracking reactor (e.g., a Thermofor catalytic cracker) is employed, 
preferably a FCC riser cracking unit. Examples of such FCC cracking units 
are described in U.S. Pat. Nos. 4,377,470 and 4,424,116. Generally, a 
catalyst regeneration unit (for removal of coke deposits) is combined with 
the FCC cracking unit, as is shown in the above-cited patents. 
Specific operating conditions of the cracking operation depend greatly on 
the type of feed, the type and dimensions of the cracking reactor and the 
oil feed rate. Examples of operating conditions are described in the 
above-cited patents and in many other publications. In an FCC operation, 
generally the weight ratio of catalyst composition to oil feed (i.e., 
hydrocarbon-containing feed) ranges from about 2:1 to about 10:1, the 
contact time between oil feed and catalyst is in the range of from about 
0.2 to about 2.0 seconds, and the cracking temperature is in the range of 
from about 800.degree. to about 1200.degree. F. Generally, steam is added 
with the oil feed to the FCC reactor so as to aid in the dispersion of the 
oil as droplets. Generally, the weight ratio of steam to oil feed is in 
the range of from about 0.05:1 to about 0.5:1. 
The separation of the thus used crackign catalyst composition from gaseous 
and liquid cracked products and the separation of cracking products into 
various gaseous and liquid product fractions can be carried out by any 
conventional separation means. The most desirable product fraction is 
gasoline (ASTM boiling range: about 180.degree.-400.degree. F.). 
Non-limiting examples of such separation schemes are shown in "Petroleum 
Refining" by James H. Gary and Glenn E. Handwerk, Marcel Dekker, Inc., 
1975. 
Generally, the separated, used cracking catalysts are regenerated, 
preferably by steam stripping for removal of adhered oil and subsequent 
heating under oxidizing conditions so as to burn off carbon deposits. At 
least a portion of the regenerated cracking catalyst composition can then 
be treated by the reactivation process of this invention, and thereafter 
be recycled to the catalytic cracking reactor, generally in admixture with 
fresh (unused) cracking catalyst. 
The following examples are presented to further illustrate this invention 
and are not to be considered as unduly limiting the scope of this 
invention. 
EXAMPLE I 
This example illustrates the reactivating treatment of a metal-contaminated 
equilibrium cracking catalyst composition with various acid solutions. The 
zeolite-containing equilibrium catalytic cracking composition was a blend 
of fresh cracking catalyst and of spent cracking catalyst (which had been 
used and regenerated in a FCC cracking operation at a refinery of Phillips 
Petroleum Company). This equilibrium catalyst composition (labeled 
"J-8802") contained about 10 weight-% zeolite, which was embedded in a 
silica-alumina matrix, 0.18 weight-% Ni, 0.32 weight-% V, 0.53 weight-% 
Fe, 0.01 weight-% Cu, 0.06 weight-% Sb, and 0.34 weight-% Na. "J-8802" had 
a surface area of about 110 m.sup.2 /g, a total pore volume of 0.18 cc/g, 
an apparent bulk density of 0.90 g/cc, and a zeolite unit cell size of 
24.36 .ANG.. 
Catalyst A was prepared by heating 100 grams of J-8802 with 1500 cc of a 
0.1 molar aqueous solution of HCl under reflux conditions for about 1 
hour. The pH of the acid solution was maintained at about 1 during 
refluxing by addition of fresh acid solution. The thus-treated catalyst 
was separated from the acid solution by filtration, washed with about 1 
liter of water, and dried for about 16 hours at 120.degree. C. About 11% 
of nickel and 29% of vanadium present in J-8802 was removed by this 
treatment with aqueous HCl. 
Catalyst B was prepared by heating 100 grams of J-8802 with 1500 cc of a 
0.1 molar aqueous solution of HNO.sub.3 under reflux conditions for about 
1 hour, followed by filtering, washing and drying, as described for 
Catalyst A. The pH of the acid solution was maintained at about 1 during 
refluxing by addition of fresh acid solution. About 9% of nickel and 20% 
of vanadium present in J-8802 were removed by this treatment with aqueous 
HNO.sub.3. 
EXAMPLE II 
This example illustrates the performance of the treated spent cracking 
catalysts described in Example I in a catalytic cracking test reactor. 
The test reactor was a MCBU (micro-confined bed unit) cracking test 
reactor, substantially in accordance with the procedure of Example II of 
U.S. Pat. No. 4,794,095. Cracking test conditions comprised a temperature 
of about 950.degree. F., a catalyst-to-oil weight ratio of 6:1, and the 
use of a hydrotreated residuum as oil feed having API gravity (at 
60.degree. F.) of 18.7, sulfur content of 0.53 weight-%, basic nitrogen 
content of 0.09 weight-%, Conradson carbon content of 6.7 weight-%, nickel 
content of 10.6 ppm and vanadium content of 12.7 ppm. Average test results 
of at least two duplicate runs for each catalyst are summarized in Table 
I. 
TABLE I 
______________________________________ 
Average Average Average 
Conversion Gasoline Hydrogen 
Catalyst (Wt-% of Feed) 
Yield.sup.1 
Generation.sup.2 
______________________________________ 
J-8802 76.2 50.0 398 
(Base Catalyst) 
A 81.5 51.4 404 
(Invention) 
B 81.3 51.5 408 
(Invention) 
______________________________________ 
.sup.1 weight% of converted feed 
.sup.2 standard cubic feed H.sub.2 per barrel of converted feed. 
Test results in Table I clearly show that extraction of the equilibrium 
catalyst J-8802 with aqueous HCl (Catalyst A) or NHO.sub.3 (Catalyst B) 
resulted in enhanced conversion and gasoline yield. 
EXAMPLE III 
This example illustrates the effect of the treatment with an antimony 
compound on the performance of acid-treated equilibrium cracking 
catalysts. 
Catalyst C was prepared by impregnating 34.0 g of J-8802 equilibrium 
catalyst with 16.4 g of a solution of 350 cc water and 3.32 g of Phil-Ad 
CA-6000 (an aqueous dispersion of Sb.sub.2 O.sub.5, containing about 20 
weight-% Sb; marketed by Catalyst Resources, Inc., Pasadena, Tex.), drying 
at 120.degree. F. for about 2 hours, and calcining in air for 1 hour at 
1250.degree. F. Catalyst C contained 1600 ppm Sb. 
Catalyst D was prepared substantially in accordance with the procedure for 
catalyst C, except that the HCl acid-washed Catalyst A was used in lieu of 
the J-8802 catalyst for impregnation with Phil-Ad CA-6000. Catalyst D 
contained 1600 ppm Sb. 
Catalyst E was prepared substantially in accordance with the procedure for 
catalyst C, except that the HNO.sub.3 acid-washed Catalyst B was used in 
lieu of the J-8802 catalyst for impregnation with Phil-Ad CA-6000. 
Catalyst E contained 1600 ppm Sb. 
Catalytic cracking tests were carried out with Catalysts C, D and E, 
essentially in accordance with the procedure described in Example I. Test 
results (averages of two or more tests) are summarized in Table II, and 
demonstrate the beneficial effect of the additional antimony treatment 
after acid treatment versus acid treatment alone (see Table I): in 
particular higher conversion and lower H.sub.2 generation. 
TABLE II 
______________________________________ 
Average Average Average 
Conversion Gasoline Hydrogen 
Catalyst (wt-% of Feed) 
Yield.sup.1 
Generation.sup.1 
______________________________________ 
C 75.6 50.3 337 
(Control) 
D 82.0 52.4 293 
(Invention) 
E 82.3 51.5 335 
(Invention) 
______________________________________ 
.sup.1 see footnotes of Table I 
Reasonable variations, modifications, and adaptations for various 
conditions and uses can be made within the scope of the disclosure and 
appended claims.