Note: Descriptions are shown in the official language in which they were submitted.
F-1736 - 1
HIGH DENSITY CATALYST ~ND METHOD
OF PREPARATION .4MD USE T~EREOF
The present invention relates to a rnethod of preparing a high
density cracking catalyst which comprises active catalytic fines
dispersed in a matrix and the use thereof in a catalytic cracking
process.
In fluidized catalytic cracking (FCC) systems a fluidized bed
of particulate catalyst is continuously cycled between a cracking zone
and a catalyst regeneration zone. Hydrocarbon cracking in the
reaction zone deposits coke on the catalyst. The cracked hydrocarbons
are separated from the coked catalyst and withdrawn. The coked
catalyst is s-tripped of volatiles and passed into the catalyst
regenerator ~here coked catalyst contacts an oxygen-containing gas to
burn off coke and heat the catalyst. Hot regenerated catalyst then
contacts the hydrocarbon stream in the cracking zone. A flue gas is
formed by burning coke in the regeneration zone.
The hydrocarbon Eeeds processed in con~ercial FCC units
no~mally contain sulfur. A significant portion of this sulfur is
deposited on the catalyst in the coke. The flue gas formed by burning
coke in the catalyst regenerator contains SOx, i.e., sulfur dioxicle
and/or sulfur trioxide.
Known methods of reducing Sx emissions from the FCC catalyst
regenerator include desulfurizing the regenerator flue gas by
conventional stacX gas scrubbing or desulfurizing the hydrocarbon feed
in a separat0 desulfurization unit. I~ese rnethods are expensive.
Catalyst modifica-tion to reduce Sx emissions from FCC
regenerators is much cheaper than currently available methods.
It has been suggestecl in U.S. Paterlt No. 3,835,031 to recluce
the amount of sulfur oxides in FCC regenerator flue gas by
impregnating a Croup II-A rnetal oxide onto a conventiollal
silica-alumina crack;ng catalyst. The attrition encolmtered ihen
~',.
a~ 7
F-173~ - 2 -
using unsupported Group II-A metals is thereby reduced. Group II-A
metal oxides, such as magnesia, when used as a component of cracking
catalysts, have a highly ~mdesirable effect on the activity and
selectivity of the cracking catalyst. The addition of a ~roup II-A
metal reduced the yield of the liquid hydrocarbon fraction and
gasoline octane.
Other patents propose reduction of Sx emissions from
regenerator flue gas by contacting the sulfur compounds with an
oxidation promoter and reactive alumina. The resulting solid
a]uminum-sulfate compound, formed in the regenerator9 is reduced to
hydrogen sulfide gas and reactive alumina in the reaction zone.
Hydrogen sulfide removal from the reactor effluent is cheaper than
feed desulfurization or flue gas desulfurization. The alumina can be
impregnated on the standard catalyst, incorporated into the catalyst
during manufacture, or admixed with a standard catalyst as a separate
particle.
It is known to impregnate standard catalysts with rare earth
oxides such as Cr203, MnO, or Co0, alone or in combinations, or
rare earth oxide with a platinum group metal oxidation promoter to
reduce the sulfur content of coke and shift the sulfur removal to the
cracked hydrocarbon effluent.
While the above-mentioned disclosures teach methods of reducing
Sx emissions by catalyst modification, the disclosed processes
require the addition of elements or compoundS to the cracking catalyst.
Cracking catalysts are solid materials which have acidic
properties. Because of -the nature of the reactions taking place, the
catalyst mus-t have high porosity. Furthermore, since the catalyst
circulates rapidly between reaction zones and burning, or regeneration
zones, it must also have resistance to abrasion, temperature changes
ancl the like.
Another problem encountered with conventional FCC catalysts is
catalyst attrition, aging and loss of activity and selectivity. The
trend in commercial fluid catalytic cracking is high density catalysts.
The higher density in conjunction with increased attrition resistance
F-1736 3
is a major factor in improving catalyst retention in a fluidized cracking
unit. As a result, the make-up rate of fresh catalyst can be reduced and
dust emissions from the flue gas stacks are lowered. At the same time,
however, the characteristic of high density must not result in the loss
of product selectivity.
Many FCC catalysts comprise a ~el of silica-alurnina in which is
dispersed particles of crystalline zeolitic catalytic material. One
method used commercially for rnanufacturing the catalysts involves
Eormation of a silica-alumina co-gel7 addition of small particles of
zeolite to the co-gel, and forrnation of catalyst particles by
spray-drying.
U.S. Patent No. 4,219,446 discloses producing an attrition
resistant zeolite-containing catalyst by preparing a zeolite-containing
silica-alumina hydro~el. One of the critical aspects of the invention is
nozzle-mixing an acid alum solution and an a~ueous solution of sodium
silicate which comprises finely dispersed kaolin clay and calcined rare
earth exchanged zeolite Y. The mixture has a p~l above 9.
U.S. Patent No. 3,957,689 discloses an attrition resistant zeolite
hydrocarborl conversion catalyst made by decreasing the pH of a sodium
silicate solu~ion to a p~I of ~.0-3.2 by adding a mixed sulfuric acid-
aluminum sulfate solution to form a buffered silica 501, adding clay
before, during or after sol formation, preparing a water slurry of a
crystalline zeolite and adjusting the p~l to about 3-5, mixing the slurry
with the buffered silica sol-clay slurry to prepare a spray dried feed
slurry.
U.S. Patent Nos. 3,520,828 and 3,939,05~ disclose preparin~ the
sil;ca ancl alumina gel via mozzle mixing of a sodi~ silicate solution
and an acid al-nn solution ~o form a hydrosol containing crystallirle
aluminosilicate fines. ~le gelled hydrosol has a p~l of about ~Ø
Despite the many advances which have been made, it would be
beneficial if FCC catalysts could be produced ~hich would reduce Sx
emissions or which would be more attrition resistant alld denser.
Ideally, both improved catalyst properties and reduced Sx emissions
could be achieved.
~f~ B3~
F-1736 - ~ -
Accordingly, the present invention provides a method of
preparing a high density FCC catalyst comprising mixing a basic
solution containing silica with an acidic solution containing al~nina,
continuousl)~ maintaining said mixture at a pH of 3.0 to 4.5 from the
initial mixing to the formation oE a gel, homogenizing the gel and
spray drying the homogenized gel to produce a high density FCC
catalyst.
In another embodiment, the present invention provides a process
for cracking sulfur containing hydrocarbon feed in the presence of a
conventional FCC catalyst operated at conventional FCC conversion
conditions, wherein at least a portion of the sulfur contained in the
Eeed hydrocarbons is deposited on the catalyst in the form of coke,
and released to the atmosphere as Sx during coke burnoff, the
improvement comprising using as the catalyst a high density FCC
catalyst prepared by mixing a basic solution containing silica with an
acidic solution containing alumina, continuously maintaining said
mixture at a pH of 3.0 to 4.5 from the initial mixing to the formation
of a gel~ homogeni~ing the gel and spray drying the homogenized gel to
produce a high density FCC catalyst, whereby the arno~ult of Sx in
regenerator flue gas is substantially reduced.
GEL FOR~TION
An acid alurn solution alld a sodiuJn silicate strearn containing a
substantial portion of active zeolite fines are purmped to a mixing
apparatus where the matrix components are mixed in such a mamler that
the mixture is contin-lously maintained at a p~l no greater than 4.5.
l~le reac-tants must be intin~ately mixed to maintain the low pll. ~lixing
tlle rnatrix colnponents through a no~zle or vigorously stirring the
cornponents sirnultaneously with or immediately following contact
maintains the desired lo~ p~l, altllough nozzle mixing is preferred.
~ le acid alum soLution is an acidic solution cornprising an
aqueolJs solution of sulfuric acid and aluminum sulfate. ~le sodil~n
silicate stream is a hasic solu~ion comprising a mixture of an aqueous
socli~ silicate solution.
~L~ 3
F-1736 - 5 -
After the acid alum solution and sodiurn silicate stream have
been mixed, the gel mixture is immediately hcmogenized, as for
example, by being passed sequentially through a Charlotte ~ill and
Matin-Gaulin homogenizer. The material is then spray dried~ The
resulting spray dried product can then be ion exchanged with ammonium
ions such as from an aqueous ammonium sulfate solution and then water
washed to remove the sulfate. The washed product can then be further
ion exchanged with rare earth ions. It will be understood that rare
earth iolls include those contained in a salt or a mixture of salt
wherein the anion can be a chloride, nitrate or acetate. The rare
earth ion rnay be, for example, cerium, lanthanum, praseodyrnium,
neodymium, samarium and ytterium. Mixtures of rare earth salts can be
used.
The steps o~ ion exchanging and spray drying are conventional
and wel]-known in the art. For example, typical ion exchange
procedures are described in ~.SO Patent Nos. 39140,249; 3,140,251 and
3,140,253. Such procedures comprise contacting the zeolite with the
salt of the desired replacing ion in warm water, followed by drying at
75 to 300C.
Accordin~ to the inven~ion, catalysts ~hich are prepared by
continuously maintaining the gelled matrix at a p~l of less than 4.5
and, preferably at a pH of between about 3-!~.5 from initial mixing to
completion thereof can be advantageously used as cracking catalysts in
conventional FCC units.
ZEOLIT~
The crystalline aluminosil;ca~e zeolite which can be used can
be chosen among the na-turally occuring crystalline zeolites such as
faujasite, mordenite, erionite, etc. Synthetic crystalline al~nino-
silicate zeolites which may be used include large pore materials such
as zeolite X and zeolite Y. The preferred crystalline zeolite useful
ln the catalyst forming method of the present invention as well as for
use in the fluid catalytic cracking process is a calcined rare earth
exchanged zeolite Y.
~2~;~3~3~
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In addition to the large pore zeolites discussed above3 it will
frequently be beneficial to use, as all or only a portion, of the
zeolite eventually incorporated into the finished catalyst, a shape
selective zeolite.
By shape selective zeolite is meant a catalyst with a
constraint index of 1 to lZ~ The constraint index is calculated as
~ollows:
onstraint Index = loglo(fraction of n-hexane remaining)
loglo(fraction of 3-methylpentane remaining)
The constraint index approximates the ratio of the cracking
rate constants for the two hydrocarbons.
ZEOLITES CONSTRAI~T INDE~
ZSM-5 8.3
ZSM-ll 8.7
ZSM-12 2
ZSM-38 2
ZSM-35 4.5
~A Offretite 3.7
Beta 0.6
ZSM-14 0.5
H-7eolon 0.L~
~EY 0.'~
Amorphous Silica-Alumina f3.6
Erionite 3
The class of ~eolites deEined ilerein is exemplified by ZS~1-5
ZSM-ll, ZSM-12, ZSM-35, ZSM-38 and other similar materials.
Natural ~eolites may sometimes be converted to this type
zeolite catalyst by vario~ls activation procedures and other treatmellts
such as base exchange, steaming, alumina extraction and calcina~ion.
Natllral minerals ~lhich may be so treated incl~de Eerrierite,
brewsterite, stilbite, dachiardite, epistilbite, heulanclite alld
clinoptiloliee.
The preferreci shape seLective 7eolites for use herein will have
a silica/al~mlina ratio in excess of 12 to 1. Zeolites with very high
silica/alumina ratios, e.g., 70 to 1, 100 to 1, 300 to 1, or evell
higher, s~lch as 39000 to 1 or 30,000 to 1, may also be l~sed herein.
3~3
F-1736 7
In general, higher silica alumina ratio materials have lower acid
activities, but better stabili~y.
Other fines that have no effect on the cracking action of the
catalyst but whose presence increases the a~trition resistance of a
final catalyst may also be added. Among these latter solids can be
mentioned the alurnina and kaolin clay matrix components. In addition,
recycled fines from the spray drying step may be used.
EXA~1E 1
~ ,e catalyst consists of 20 wt. ~ rare earth exchanged and
calcined zeolite Y (REY) in a silica-alurnina-clay matrix. The REY is
formed from ion exchange of the sodium form of zeolite Y such that 68%
of the sodijm cations have been replaced by rare earth cations
including Sm, Nd, Pr, Ce, and La having the distribution as indicated
in Table 1. After ion exchange, the resulting REY product was
calcined for about 10 minutes at 649C (1200F). The chemical
composition of the REY is presented in Table 1.
The REY was incorporated in a gel matrix consisting of 60.5
wt. % SiO2, 4.5 wt. % A1203 and 35 wt. % clay. The catalyst was
prepared as follows: 2100 grarns of Georgia kaolin clay on a dry basis
was mixed with 7.3 grams Q-brand sodium silicate ~8.9 wt. % Na2O,
28.7 wt. % SiO2) and 3750 grams H20 and gro~cd for one hour in a
bal] mill. The clay slowly was brought to 30~ solids by adding 1150
grams H2O. 1500 grarns of the REY on a dry basis was mixed with 9
grams of a dispersan-t, '~arasperse N"~and 3000 grams H20 and ground
~or one hour in a ball mill. l~e REY slurry was brought to 25% solids
by adding 1500 grarns H2O 1263 kg (27.83 poullcls) ~-brand sodium
silicate was mixed well with 7.51 kg (16.56 poullds) H2O and the clay
and REY slurries were aclded, stirring continuously ulltil the solution
was used. An acid al-~ solution was prepared by mixing 1.65 kg (3.64
pollnds) A12 (SO~)3 (MW=616) with 27.35 kg (61).29 powlds) 1l2n
and 0.41 k~ (0.9 pound) 1-1~SO~ (96.2 percent acid).
~i '',~
3~
F-1736 - 8 -
The acid alurn and clay, REY, silicate solutions were mixed
through a 0.74 rnn (0.029 inch) diameter nozzle at solution rates of
345 cc/min for the acid alum and 340 cc/min for the clay, REY,
silicate solution. The resulting mixture had a pH of 4.0-4.15.
The mixture was i~nediately homogenized and spray dried with an
inlet temperature of 371C (700F) and an outlet temperature of 177C
(350F).
l~e resulting spray dried product was ion exchanged with 5%
aqueous ammonium sulfate so]ution and then water washed substantially
free of s~l~ate. The washed product was then further ion exchanged
with 1% aqueous solution of rare earth chloride, water washed
substantially free of chloride and dried at l21C ~250F) for about 40
hours in air. The physical and chemical properties of the final
catalyst are given in Table 2.
EXA~LE lA
The catalyst of Example 1 was impregnated with a solution of Pt
(NH3)4 C12 containing enough Pt to impregnate the catalyst with
3 ppm. Enough solution was used to fill the catalyst pores. After
impregnation, the catalyst was dried in air for 16 hours at 121C
(250F).
EX4~LE 2
l~lis example describes an alternative methocl of forming FCC
catalyst containing 20 wt~ % rare earth exchanged and calcined RY
from Example 1 in a high-density semi-synthetic silica~alumina-clay
matrix. The chemical composition of the REY is given in Table 1.
The REY was incorporated in a high-density clay-gel matrix
containing 67.9nO SiO2, 10.1% A12O3, 2~ ZrO2 a~ld 20% clay. The
matrix was prepared by first dissolving in mixing tcmk A, 2365 grams
of alwninum sulfate (17.2% A12O3) in 30.1 kg (66.4 pounds) water,
a portion oÇ which was ice. The pH of ~he solution was adjusted to
l.4 at UC (32F) by adding 120cc concentrated sulfuric acid.
F-1736 - 9 -
In mixing tank B, 930 grams of Georgia kaolin clay (86go solids)
were added to 24.2 kg (53.4 pounds) water~ a portion of which was
ice. To this slurry, 9425 grams of Q-brand sodium silicate tPQ
Corporation, 8.9% NazO, 28.8o SiO2) was added uniformly over a
thirty rninute period. The temperature of the resulting slurry was 0C
(3ZP) and the pH was 11.6.
The contents of mixing tank B were then slowly added to mixing
tank A. After 7500cc of slurry from mixing tank B had been added, the
rnixture had a pH of 3.6 at 4C ~40F). 200cc of concentrated sulfuric
acid was added to reduce the pH to 1.7. An additional 7500cc from
mixing tank B was added until the mixture pH was 3.4 at 8C (47F).
An additional 200cc of concentrated sulfuric acid was added to mixing
tank A, reducing the pH to 1.9 at 11C (52F). The remainder of the
slurry from mixing tank B was then added slowly to mixing tank A. The
resultant gel-slurry had a pH of 3.6 at 13C ~55F).
Next> a slurry prepared by combining 167 grams of sodium
~irconium silica-te (~8~ ZrO2)~ 108cc of concentrated sulfuric acid
and 1620cc water was added to the gel-slurry over a 15 minute period,
reducing the pH of the entire mixture to 3.~.
The REY (20 wt. %) was added to the clay-gel mixture so
formed. The pH was then adjusted to 4-4.5 by addition of 6S2cc of S0
wt. ~O sodium hydroxide. The mixture was filtered to remove wa~er and
dissolved salts and then reslurried with 10.~ kg (23 po~mcls) of
water. The gel-2eolite mixture was then homogenized and spray dried
at 371C (700F) inlet temperature, 177C (350F) outlet temperature.
The resulting spray dried product was ion exchange~l with 5~0
a~ueous amlnonium sulfate solution, then water washed substantially fre0
of sulEate. The ~shecl product was then Eurther iOII exchanged Wit}l 1
aqueous solution of rare earth chloride, water washed substantially
free o~ chlori(le and then dried at 121C (250F). The physical and
chemical properties of the final catalyst are given in Table 2.
F-1736 - 10 -
EX~MPLE 3
The catalyst of this example, consists of 25 wt. % ZSM-5 in a
silica-alumima matrix. The gel matrix consists of 93 wt. % SiO2 and
7 wt. % A12O3.
80.34 pounds of ~-brand sodium silicate ~8.9 wt. ~ Na2O,
28.7 wt. % SiO2) was mixed with 27.8 kg (61.3 pounds) of H2O. An
acid-alum solution was prepared by mixing 4.75 kg (10.48 pounds) of
A12~SO~)3 (MW-616) with 50.1 kg (110.5 pounds) of H20 and 1.88
kg (4.15 pounds) of H2SO4 (96.3 wt. % acid).
The acid alum and silicate solutions were intimately mixed in a
nozzle at rates of 410 and 365 cc/min, respectively. The resulting
mixture had a pH of 3.5.
The pH was increased to 4.5 by adding NH4OH (29.6 wt. %)
causing the mixture to gel while stirring continuously.
A sufficient quantity of a 20 wt. % slurry of ZSM-5 and water
was added to the gel to give 25 wt. % ZSM-5 in the final catalyst, on
a dry basis.
The gel matrix-ZSM-5 mixture was filtered to 16 wt. % solids
and reslurried to 11 wt. % solids with H2O. This mixtrure was
immediately homogenized and spray dried with an inlet temperature o-
371C (700F) and an outlet temperature of 177C (350F).
The resulting spray dried product was ion exchanged with 5 wt.
% aqueous ammonium sulfate solution and water washed substantially
free of sulfate. lhe product was then dried at 121C (250F) for
about 40 hours. The physical and chemical properties of the final
catalyst are given in Table 2.
EXAMPLF 4
This example describes another process of forming a
high-density FCC catalyst containing 25 wt. % ZSM-5 in a
semi-synthetic matrix consisting of 74.4 wt. ~ SiO2, 5.6 ~t. %
A12O3 and 20 wt. '~ clay.
The matri~ was prepared by first dissolving, in mixing tank A,
1306 grams of al~mlinum sulfate in 25.6 kg (56.5 pounds) wat~r, a
~Lf~
F-1736 - ll -
portion of which was ice. The pH of the solution was adjusted to Q.7
at 25C (77F) by addition of 537cc of concentrated (96.2 wt. %)
sulfuric acid.
In mixing tank B, 930 grams of Georgia kaolin clay were added
to 28.8 kg (63.4 pounds) water, a portion of which was ice. To this
slurry 10,333 grams of Q-brand sodium silicate (PQ Corporation, 8.9
wt. ~ Na20, 28.8 wt. % SiO2) was added uniformly over a 30 minute
period. The temperature of the resulting slurry was 6C (43F) and
the pH was 11.4.
The contents of mixing dr~n B were then added to mixing drum A
over a one hour period. The final mixture pH was 3.6 at 19C (67F).
The pH of the mixture was adjusted to 4.1 by addition of 330cc of 50
wt. % sodium hydroxide.
The ZSM-5 (25 wt. %) was added to the clay-gel mixture so
formed and the zeolite-clay-gel mixture was Eiltered to remove water
and dissolved salts. It was then reslurried with water, homogenized
and spray dried at 371C (700F) inlet temperature 177C (350F)
outlet temperature.
The resulting spray dried product was ion excllanged with S wt.
% aqueous ammonium sulfate solution, then water washed substantially
free of sulfate and then dried at 121C (250F). The physical and
chemical properties of the final product are given in Table Z.
EXA~LE 5
The catalyst of this example was prepared as follows using REY
from Example l. I~e matrix of this catalyst WRS also a gel matrix
consisting of 60.5 wt. % SiO2, 4.5 wt. % A1203 and 35 ~
clay. 1750 grams of Georgia kaolin clay on a dry basis was mixecl with
~9.9 kg (llO.l pounds) H20 10,495 gr~ns of Q-brand socliurn silicat.e
was added slowly over a 30 minute period. I~e admi.xture was then
heated to 49C (120F) and 541cc of sulfuric acid (96.7 wt. ~ acid~
was added at a uniform rate over one hour to adjust the pH to clbout
10.4. The resulting gel which formed was aged at 49C (20~F) for 30
minutes and then cooled to ambient temperature. Alumina was then
?;3~
F-1736 - 12 -
incorporated by adding a 20 wt. ~ aqueous solution of aluminum sulfate
(17.2 wt. ~ Alz03) over a 30 minute period to a pH of about 3.9.
The pH of the mixture was then adjusted to 4.5 to prevent aging or
deterioration of the gel, using 50 wt. ~ NaOH in water. The E~Y (20
wt. %) was added to the clay-gel mixture.
The resulting composite was homogenized and spray dried as
described in Example 1 and the spray dried product was ion exchanged
and dried again as described in Example 1. The physical and chemical
properties of the final product are given in Table 2.
EXAMPLES 6,_7, 8 and 9
The catalysts of these examples~are commercial cracking
catalysts sold under the names Super-D (manufactured by Davison
C.hemical, E)ivision of W. R. Grace ~ Co.), FS-30, FOC-90 and OPC-4 (all
manufactured by Filtrol Corp.), respectively. The physical properties
of each are given in Table 2.
~YA~LE 10
The starting material for the catalyst of this example is a
commercial catalyst sold under the name HFZ-20 (manufactured by
Engelhard Minerals ~ Chemical Corp.). This material was ion exchanged
with a solution of rare earth chloride in water containing enough rare
eartil chloride to give 3 wt. % RE203 on the final catalyst. After
exchange, the catalyst was water washed substantially chloride free
and dried in air for about 16 hours at 121C ~250F).
EY~MPIE IOA
[~e startirIg material for this example is the same as for
ExanIple lO. This mateIial was exchanged with the same solution as in
E.Yample 1() which also incl~(lelI Pt(NI-I3)4CI2, enough to give 3 ppm
E't on the final catalyst. ~le catalyst was washed .IIld ~Iriecl as in
ExaIlll)le 10.
Z~ 3~
F-1736 - 13 -
EXA~LE 11
The catalyst of this example consists of 25 wt. % ZS~1-5 in a
silica-alumina matrix. The gel matrix consists of 93 wt. % SiO2 and
7 wt. % A1203, percentages by weight.
The catalyst was prepared as follows: 12.95 kg (28.55 pounds)
of Q-brand sodium silicate (8.9 wt. % Na2O, 28.7 wt. % SiO2) were
mixed with 9.8 kg (21.6 pounds) of H2O. An acid-alum solution was
prepared by mixing 1691.0 grams of A12(SO4)3 with 17.8 kg (39.2
pounds) of l-l2O and 670.2 grams of H2SO~ (96.3 wt. % acid).
The acid-alum and silicate solutions were pumped separately but
at the same time into a 30 gallon mixing drum at rates of 380 and
365cc/minute, respectively. 6000cc of H2O were placed in the bottom
of thè mixing drum so that mixing could begin as soon as the solutions
contacted the water. In the bottom of the barrel was placed a
stirrer. The resul-ting mixture had a pH of 3.5. Additionally, ice
was added to lower the temperature to 13C (55F).
The pH was increased to 4.5 by adding l95cc of NH40H ~29.6
wt. %) causing the mixture to gel while stirring continuously. A
sufficient quantity of a 20 wt. % slurry of ZSM-5 and water was added
to the gel to give 25 wt. % ZSM-5 in the final catalyst on a dry basis.
The gel matrix-Z~-5 mixture was filtered to 18 wt. ~ solids
and reslurried to 12 wt. % solids with 13.8 kg ~30.38 pounds) of
~l2 This mixture was immediately homogenized and spray dried with
an inlet -temperature of 371C (700F) and outlet temperature o~ 177C
(350F).
The resulting spray dried particles were ion e,Ychanged with 5
wt. ~ aqueous c~lmonium sulfate solution and then water washed
substantially free of sulfate. Tlle particles were then dried at 121C
(250F) for about ~0 hours. The physical and chemical properties of
the final ca-talyst are given in Table 2.
3~3
F-173S - 14 -
TABLE 1
CHEMICAL C MPOSITION OF CALCINED REY
OF EXAMPLES 1, 2 AND 5
Na, wt. % 3.2
Total RE2O3, wt. ~ 15.9
~n2O3, wt. % 0.10
Nd2O3, wt. % 3.70
Pr6ll' wt. % 1.05
CeO2, wt. ~ 1.61
La203, wt. % 9.47
SiO2, wt. % 61.4
A123~ wt. % 21.7
From a comparison of the physical and chemical properties of
the individual catalysts set forth in Table 2, it can be seen that the
packed density and pore vol~e of the catalysts formed in accordance
with the present invention~ Exc~mples 1-4 and 11 are comparabl~ to those
of a typical commercial catalyst such as the catalyst of Example 6.
In Example 5, a catalyst was formed with the sc~ne chemical composition
as the catalyst of Ex~m?le 1, but utilizing a different forming Dlethod.
The ca~alyst of Ex~mple 5 has a more open structure as evidenced by
the hiKher surface area and pore vol~ne and lower packed density.
E~ LE 12
Fresh catalysts from Examples 1 and 5-10 were steam treated in
a fLuidized bed for 4 hours at 760C (1~00F) with 100~ stearn at
atmospheric pressure. The steamed catalysts ~ere used to crack a
high-sul~ur sour heavy gas oil, the properties of which are given in
'I'able 3, in a fixed fluidized bed test unit whicil simulated ~:CC
cracking. Tests conditions were 515C ~60~F) 1.0 minute on-s~ream.
F-1736 - 15 -
TABLE 2
P~NSICAL AND CHEMICAL PROPERTIES OF CATALYSTS
C _ cal ~nalysis Ex. 1 Ex. 2 Ex. 3* Ex. 4* Ex. 5 Ex. 6
Na2O, wt. % 0.15 0.190.03 0.12 0.12 0.70
~F2O3, wt- ~ 4.83 4.41 --- --- 4.95 3.02
SiO2, wt. % 70.1 71.1 86.6 81.~ 70.1 61.0
A123' Wt- % 18.9 16.5 6.2 11.9 20.1 29.9
Physical Properties
Packed ~ensity, gm/cc 0.83 0.97 0.87 0.76 0.61 0.86
Pore Volume, cc/gm 0.22 0.090.23 0.26 0.55 0.23
Surface Area, m /gm 96 96 167 249 181 102
* Physical properties for Examples 3 and ~ were determined after treatmen~
0.5 hours, 649C (1200F), 100~ N2 atmospheric pressure in a fluidi~ed
bed. All other ca~alysts were steamed.
~2;~ 3~
~-1736 - 16 -
TABLE 2 (cont.)
P~SIGAL AND CHEMICAL PROPERTIES OF C~TALYSTS
Chemical Analysis Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 10a Ex. ll
Na2O, wt. % 0.52 0.69 0.54 0.92 0.91 0.06
RE2O3, wt- % 2.99 0.49 3.49 3.03 3.41
SiO2, wt. % 51.0 50.5 47.2 37.837.6 87.6
AlzO3~ wt. % 40.3 40.4 43.6 57.457.2 6.4
sical Properties
Packed Density, gm/cc 0.85 0.73 0.79 0.90 0.94 0.77
Pore Volume, cc/gm 0.37 0.46 0.41 0.42 0.42 0.24
S~rface AIea, m2/gm 137 141 129 253 239 ---
^~22~33~
F-1736 - 17 -
TABLE 3
HIGH SULFUR SOUR HEA~Y GAS OIL
Gravity, API 24~3
Density, g/cc 0.91
Aniline Pt. F/C 171J77
Sulfur, wt. % 1.87
Nitrogen, wt. % 0.10
Basic Nitrogen, ppm 327
Conradson Carbon, wt. % 0.28
Viscosity, KV at 99C ~210F) 3.6
Bromine No. 4.2
Refractive Index at 21C (70~) 1.50~0
Hydrogen, wt~ ~ 12.3
Molecular wt. 358
Pour Point, F 85
C 29
Paraffins, wt. % 23.S
Naphthenes, wt. % 32.0
Aromatics, wt. % 44.5
CA, wt. % 18.9
Test conclitions and product distributions are given in Table
4. ~le following abbreviations are used:
G = C5 Gasoline = Gasoline
A = Alkylate
G~A = Gasoline ~ Alkylate
~Z~3~3
F-1736 - 18 -
TABLE 4
Catalyst Exam~e 1 5 6
Catalyst/oil, wt/wt 2.5 2.0 2.5
W~V, Hr~l 24.0 30.0 24.0
Conversion, % Vol70.8 70.0 70.3
Gasoline, % Vol 55.5 57.5 55.2
Total C4, % Vol 16.4 13.2 15.3
Dry Gas, % Vol 8.5 7.8 8.5
Coke, wt. % 4.0 3.5 4.4
G + A 76.1 76.2 75.0
RON + O, G 88.7 86.9 87.6
RON + 0, G -~ A 90.1 88.6 89.2
Conversion/Coke, Vol/Wt 17.7 20.0 16.0
G/Conversion, Vol/Vol 0.784 0.821 0.785
G/Coke, ~ol/Wt 13.9 16.4 12.5
F-1736 - 19 -
The catalyst of the present inven~ion ~xample 1) has the sameactivity as the commercial catalyst, Super-D (Example 6) as shown by
equivalent conversion at the same catalyst/oil ratio. The catalyst o
Example 1 is less active than the catalyst of Example 5 because of the
higher diffusional resistance provided by the more closed structure.
The catalyst of Example 1 yields as much gasoline as Super-D. This is
accompanied by an increase in the research clear octane number. The
total C4 yield of the ca-talyst of the present invention is greater
and with less coke formation than Super-D.
Lower secondary cracking rates due to the greater diffusivity
are responsible for the higher gasoline yield and lower C4, dry gas
and coke yields of Example 5 catalyst. This also causes the octane
nL~nber of the gasoline to be lower as the lower octane components of
the gasoline are not cracked out.
When the potential akylate of the three catal~sts is included
in the analysis, the total gasoline yield of Example 1 is increased to
the amount of Example 5. A significant octane advantage still exists
for the gasoline of Example 1. The Super-D catalyst has a deficit in
both total gasoline yield and octane number.
EXA~LE 13
The sulfur emissions from coke burnof were determined by
oxidizing spent catalyst in oxygen at 649C (1200F) and passin~ the
effluent gas through a 3% solution of hydrogen peroxide in ~ater, thus
converting SO2 to SO3 and absorbing all of the SO3. ~le sulfate
formed was ~itrated as sulfuric acid with standard base ~aOH.
Table 5 presents the sulfur emissions of the example catalysts
in several ways. The sulfur on-catalyst (S/CAT) fixures give an
indication of the anlount of sulfur released per weight of catalyst
while the sulfur in coke (~ S/C) values relate the sulfur released to
the amount of coke hurned. The third set of figures, sulfur per
vol~Dne o~ feed converted, is influenced by the activity of the
catalysts.
~2;~3~
F-1736 - 20 -
TABLE 5
SUL~ EMISSIONS OF COKED CATALYSTS
Catalyst lb S/bbl
Example % C/Cat S/CAT, ppm % S/C feed converted ~g S/m3
1 1.338 71 0.53 0.093 0.27
1.378 79 0.57 0.089 0.25
la 1.399 69 0.49 0.092 0.26
1.562 151 0.96 0.189 0.54
6 1.487 280 1.88 0.366 1.05
7 1.511 184 1.18 0.230 0.66
8 0.983 157 1.72 0.215 0O61
9 l.962 324 1.65 0.398 1.14
2.257 155 0.69 0.179 0.51
10a 2.259 242 7.07 0.285 0.81
From Table 5, it can be seen that when the matrix components
of a fluid cracking catalyst are intimately mixed as previo~sly
described such that the pH is maintained at 3.0-4~5, a very substantial
reduction of sulfur emissions results. At least a 50~ reduction
occurs compared to all catalysts in sulfur on catalyst. The effect of
a platinum oxidation promoter in this example is demonstratad by the
catalyst of Example 10a. Compared to the catalyst of Example 10, an
increase in the sulfur emissions is measured. This has not been the
case in commercial measurements of Sx emissions Eor ~its operating
with some degree of promoted CO combustion.
