CA1045069A

CA1045069A - Hydrocarbon cracking process

Info

Publication number: CA1045069A
Application number: CA212,120A
Authority: CA
Inventors: Edwin W. Albers; Julius Scherzer
Original assignee: WR Grace and Co
Current assignee: WR Grace and Co
Priority date: 1973-11-15
Filing date: 1974-10-23
Publication date: 1978-12-26
Also published as: ZA747306B; NL7414863A; FR2251615A1; IT1025721B; DE2453805C2; DE2453805A1; FR2251615B1; JPS5080288A

Abstract

HYDROCARBON CRACKING PROCESS

Abstract of the Disclosure A mixture of rare earth hydrogen Y type zeolite, and hydrogen or transition metal exchanged mordenite, calcium exchanged type A zeolite, or hydrogen exchanged erionite is used as a catalyst for the conversion of hydrocarbons. The rare earth hydrogen Y, and exchanged mordenite, type A zeolites, or hydrogen exchanged erionite may be advantageously combined with amorphous matrix components such as silica, alumina, silica-alumina hydrogel and/or clay to form cracking catalyst compositions of the fluid or moving bed type which are particularly active for the production of C3 and C4 hydrocarbons, and/or which show improved coke selectivity.

Description

5~

This invention relates t~ the preparation of hydrocaxbon conversion catalysts, and more particularly to the preparation of hiyhIy active zeolite type catalysts which are capable of converting petroleum hydrocarbons such as gas oil, boil ng in the 400-1050F range, to lower molecular weight derivatives such as gasoline.
For many years cation exchanged zeolites particularly those of the rare earth exchanged type X or Y
zeolite, i.e., synthetic faujasite, have been found to be particularly useful in the converting of petroleum feedstocks -such as gas oil into lower molecular weight derivatives such --as gasoline.
Prior art catalysts, while possessing a high degree of activity and desired selectivity when compared to the previously available amorphous type hydrogel catalysts, are found to be relatively limited in terms of producing desirable products other than gasoline. Substantial attempts have been made to alter the characteristics of rare earth exchanged faujasites so as to produce a product stream which is higher in desirable end products such as olefins and/or gasolines high in aromatic content. ~owever, it is found frequently that modifications of faujasites by the exchange with additional metals other than rare earths has frequently led to the preparations of catalysts which tend to produce undesirable products such as dry gas and coke.
Thus, in accordance with the present teachings, ;
a method is provided for the catalytic cracking of hydrocarbons which method comprises contacting a hydrocarbon feedstock with a catalyst comprising a) rare earth-hydrogen type Y zeolite, b) a second zeolite consisting of exchanged mordenite having ~-the general formula M-mordenite wherein M is selected from the group consisting of hydrogen, rare earth, cobalt, nickel and

-2- ~

., , . ., . : . .. . .

~45~6~
group II cations undex catalytic cracking conditions and recovering the pxoducts foxmed thereby.
These and still further aspects of the present invention will become readily apparen-t from the detailed description and specific examples.
Broadly, our invention involves cracking a hydrocarbon feedstock using a catalyst composition which comprises a mixture of rare earth hydrogen exchanged type Y
zeolite (RE-H-Y), and a metal or hydrogen exchanged mordenite (H or M-Mord.), or calcium exchanged type A zeolite (CaA) or hydrogen erionite (H-Er.).
More specifically, we have found that an `
extremely useful hydrocarbon conversion catalyst composition may be obtained if rare earth hydrogen Y zeolite is combined with from about 5 to 40% by weight of one of the following:
1) A transition metaI or hydrogen exchanged mordenite which possesses the general formula M-Mord., where M
is selected from the group consisting of hydrogen and metals such as rare earth, cobalt, nickel, group II cations, and other di- and trivalent transition metals and Mord. represents ~;
the negatively charged mordenite.
2) A calcium exchanged type A zeolite.

3) A hydrogen exchanged erionite.
In a particularly preferred embodiment of the present invention, the combination of rare earth hydrogen Y and exchanged mordenite or type A zeolite or erionite is combined -` ~O~S'J6~

with an inorganic oxide matrix such as silica, alumina, silica-alumina hydrogel and/or clay- Such compositions ma~ be readily formed into microspheroidal products so as to provide the -~
$o-called fluid cracking catalysts, or alternatively the composition may he formed into relatively large sized beads so as to provide the so-called moving bed type catalysts.
The rare earth hyarogen Y type zeolite used in the practice of the present invention is described in U.S. Patent No. 3,676,368 of Scherzer et al.
Briefly, the rare earth hydrogen Y zeolite comprises faujasitic zeolite having a silica-alumina ratio of about 3 to 6 which has been rare earth exchanged in a particular manner to produce a zeolite which contains on the order of 6 to 14% by weight rare earth ions measured as rare earth oxides, and less than 0.5~ by weight alkali metal ions measured as alkali metal oxides. The rare earth hydrogen Y zeolite is prepared by first e~changing an alkali metal Y zeolite, usually sodium Y zeolite having a silica-alumina ratio on the order of 3 to 6 with a solution of rare earth ions at a pH of from about 3.0 to 3.5 to reduce the alkali metal oxide content to a level of less than about 4%
by weight. Subsequently, the exchanged zeolite is calcined at a temperature of 800 to 1400F for a period of about 1 to 3 hours. Finally the product is a~nonium ion exchanged to further reduce the alkali metal content to less than about 0.5~ by weight.
The metal exchanged mordenite used in the practice of the present invention is obtained by reacting sodium mordenite which possesses a si:Lica to alumina ratio on the order of 10 to 12 and an alkali metal content on the order of about NazO with a solution of metal cations. Moraenite used in the ~ '' ' .

. ,, , , , , . . , . , : ": , 1~4~69 practic~ o~ the ~re~.ent i~yent~Qn i~ readil~ .ayailahl~ ~rom commercial source$ ~uch as the.~ortQn CQ. ~hich sells mordenite :~
under the commercial name o~ Zeolon.*
The exchan~e of t~e morden~te i5 conducted în conven~
tional manner using aqueous solutions of the desired metal cation~. The exchange is conducted in a manner where~y the alkali metal content in the morden~te i5 reduced to a level of less than about Q.1% by weight. ~t is generally found that thP mordenite particularly useful for the practice of the lQ .... present invention ~ill contai.n on the order of from about 1 to :-~
:6~ by weight metal oxide selected fr~m ~he group consisting of rare earth cobalt, nickel, group I~ cations. .
The calcium exchanged type A zeolite is obtained by exchanging type A zeolite with calcium salts as set forth in U.S. 2,882,243 to Milton. The resultant CaA will contain about 18% Ca oxide a~ calcium ions H-erionite is obtained from natural erionite by acid treatment at boiling temperature. ~ ~ :
To prepare the catalysts contemplated herein, the rare ~-2a earth hydrogen Y type zeolite component and the mordenite can . .
vary from about g:l to 1:1 parts by weight H or M-Mord.
Similarly, 1 part CaA, or H-Er. is mixed with 1 to 9 parts :.
by weight rare earth hydrogen Y zeolite. The precise ratio of exchanged type Y zeolite to exchanged mordenite will depend ..
upon the:properties which are desired in the final catalyst com- ~ .
position. For.example, it is found that i$ hydrogen mordenite .~:~
is admixed with the rare earth hydrogen Y zeolite, a hydro- :.
carbon.cracking catalyst i~ o~tained which is particularly effective for the productLon of low coke. On the other hand, 3Q if a relatively small amount of the metal exchanged mordenite .* Trademark .
- 5 - .. .

.

1~4~ g such as~ rare earth ex~h~n~ed mordenit~ I~ com~ined ~ith the exchang~d type ~ z~ol~te, catalyst~ are o~tained ~hich are part~cularly e~ect~e ~or the production of C3 and C4 hydrocar~ons.
W~en commercial catalysts are prepared using the unique com~înation of exchanged t~pe Y zeolite and mordenite or CaA
or H-erionite contemplated herein, the zeolites are generally formed into catalyst particles which are microspheroidal, that is particles having a size from a~out 5Q to 300 microns which lQ are particularly useful in the fluid catalytic cracking of hydrocarbons. It is also contemplated that the presently contemplated combination ~ zeolites may ~e formed into part-icles which possess sizes on the order of up to 1/8 inch particles which are par~icularly useful in the moving bed ca alytic reacting of hydrocarbons.
The combination of zeolites may be formed into catalysts using a minimum or substantially no binders so as to provide a catalyst which comprises essentially la~% zeolite. Alter-natively, 5 to 50~ ~y weight of thP combination of zeolites may 2Q be com~ined with from about 5~ to ~54 by weight of inorganic oxide matrix. Typical inorganic oxide matrixes include silica, alumina, silica-alumina hydrogel~. The preferred combination of the catalyst is a blend of a~out 5 to 15 weight percent of the zeolite component and a~out 95 to 85 weight percent of an amorphous silica alumina component. It is also contemplated that the matrix may comprise or contain clay such as kaolin and chemical or thermally modified kaolin.
The catalysts prepared hy way of the present invention are found to possess excellent stability for elevated temp-3~ eratures and steam. Furthermore, it is found that the activity and selectivity characteristics of the catalysts are exception-ally good for the productlon of gasoline and other valuable petroleum derivatives.

' ' . ; :

S~169 The cracking i5 carried out at a temperature of 700-1200~F, a catalys ~ oil ratio of 0.5 to 30 and a contact time of 0.5 seconds to lO minutes. The pre~erred operating conditions are a temperature of 800-1050F a catalyst to o~l ratio of 3~8 and a contact time of lO seconds to 5 minutes.
Having described the ~asic aspects of the present invention, the following examples are g~ven to illustrate specific embodiments thereof.

7 - ;.
~` ,, ~,1 .~'.' , ~ ", , jl .

EXA~LE 1 A. A ~a~le. ~ RE-H-~ wa~ Pxe~ared aS ~Qllows:
12 sa ml. of commercial rare earth chloride ~olution, :.
containing ~0 ~t. % REC13-6H20, was diluted with 64Q0 ml. .
of deionized ~.I.~ ~ater to form c~mponent A. Separately, 32QQ g Cdry basisl of NaY zeolite, containing 30~ H20, ~as blended into 9760 ~1. o~ D.I. ~ate.r to ~orm component `:
B. T~e two components were mixed together and the ~H of the resulting slurry ~as ad~usted to 3.5 with HC1. The lQ acidified ~lurry was ~eated for 45 minutes at 9Q~C, then filtered and ~ashed w~th 80Q0 ml. of water acidified with ;
a ml. of 5 N HCl. The filter cake Was then washed chloride free with D.I. water, dried at 105QC *or 2 hours, and calcined :~
at ~QC for 2 hours in a muffle furnace. The calcined ~:
material, which contained about 5% Na20, was ammonium exchanged with a lQ~ ammonium sulfate solution, until the sodium level dropped to about Q.2~. The material was washed sulfate `
free with D.I. water and dried at 105C. Analytical data (calculated on a dry basis~: 13.5~ RE2O3, 0.2~ Na20, Surface .
2~ Area=798 m2/g. ..
B. Samples of hydrogen and metal exchanged mordenite .
were obtained as follows~
1. H-Mordenite u~ed below was a commercial product from the Norton Co. identified as Zeolon H. The Zeolon H had a silica-alumina ratio of 12 and a surface area of 520 m2/g. .
2. Rare earth, hydrogen mordenite (RE-H-Mord~) was prepared from Na-mordenite, also a Norton product. The prep- .. .
aration was done by the follo~ing procedure: 50 g (dry basis) of sodium.mordenite was blended with 20a ml. of D.I. water. 20 3~ ml. of a commercial rare earth chloride solution, containing about ;:

.:. ~ ..
, ~ , .. ............

5~69 6Q~ rar~ earth chlori~d~ cry~tal~ s~ dijluted ~ith 18~ ml. of water. The ~rdenite was mrxe~ ~nto the rar~ earth chloride solution, and the resulting slurry ~as refluxed at boiling for one hour. The material ~as then ~iltered, ~ashed chloride free, dr;ed at llQC for 2 hours, and then calcined at 540C
for 3 hours in a muffle furnace. Thls material was then ammonium exchanged with a 1~% ammonium sulfate solution, until the remaining sodium ~ons were removed. The product contained 5.2% rare earth oxide and had a surface area of 430 m2/g.
1~ 3. Co~alt, hydrogen mordenite ~Co-H-Mord.~ was pre- -pared ~y co~alt exchanging an ammonium-mordenite zeolite.
Ammonium-mordenite ~as o~tained by ammonium ex~anging co~mercial Na-mordenite with a 10% ammonium sulfate solution. To prepare Co-H-Mord., 25 g dry ~asis of ammonium mordenite was blended - ~
into lQ0 ml. of water. This zeolite slurry was mixed with a ;
solution containing 10 g CoCl276H2O dissolved in 100 ml. of water. The mixture ~as refluxed under boiling for one hour, filtered, washed chloride free and dried at llaC for 2 hours.
The final product contained 2.7% CoO (on a dry ~asis) and had 2Q a surface area of 445 m2/g.
C. Samples of catalysts were prepared by combining various quantities of the RE-H-Y & metal or H-mordenites prepared in A ~nd B above. The catalysts were prepared by blending 10~ by weiy~t (silica-alumina basis~ zeolite or zeolite blend with 90~ by weight amorphous ~ilica-alumina-clay matrix. The m~trix comprised 6a% amorphous silica-alumina hydrogel (which contained 25% A12O3 and 75% 8ilica) and 40%
kaolin clay.
The microactivîty data ~as obtained using a reaction , 3~ temper~ture of 9Q~F., a 16 weight hourly spaced velocity (WHSV), and West Texa~ Devonian gas oil feedstock after steam treating the samples of 135QF. for 8 hour~ at 15 psig steam. Comparison "',~ '' ""''.

_ 9 _ .. . . . ... .. ..

-~5~9 samples were prepared using a typical prior art calcined rare d earth exchange type Y faujasite (CREY) such as is set,,forth in U.S. 3,402,996 to Maher, et al.
The characteristics and test data developed ~or these catalysts is summarized in the ~ables below (I and II).
"' ', ....

. .

~1~)4S~9 ,, ~ o o ~
K c~ Lo ~ tY') D o co cn O ~1 O ~ 1--.;, :
;~

a) .. .~
a ~r ~ er ~ ~ o co o o o ~r . ~ ~ ,:, X . ~, .~ '~
~ ~ : . :
U~
o ~ o ~ o ~ oo ' ." ', E~ ." '~: ' 7I: ~ ~ .
~a .

H I ~ ~ ~ C~ o ~ ~
(U ~ ~ o 1` ~ o .-1 o ~
~3 h ~ :t; ~

";~ ' ' 1~ .,,", ~. , ~ ~J . ' ~ .
~ ~ 1, g :d ~ ~ o ~r ~,, ' O i~ o~ ~ I~ a~ tncn ~ ~D ~ O ~ O ~D U~ '.
~ ~ ;".':' "
.~ ~ ';''.
rl ,:,.. ...

D

O ~ " a ~ ~ O O O
a) ~ 0 ~ ~ U~
~1 ,1 1a~ 3i > O ~ ` O
~ I~ ` 11 11 C.) * + O O + +
0 0 1:~ 0 0 ~ ~ ~1 d' I ~r Ir7 ~ Lr\ U~ O `. ' en u~ K El U ~ ~ U rl C~ C.) V O ~ ~,) t ) C ) . :

.`., -:

' ~
; ':

~09L:~69 O u~ P ~ ~ O O e~
+ + ~o ~o + + ~ m G~ q O ~ o n ~ 0~O
O O O ~ O O ~ ~ Z
o I~ o ~ d o~O
C ~ 0~ d~ dO
d~O , ~
C ~'"

~ ~ O ~ æ
~I ~ ~- o o co ~ o~ ~d ~
C~ .. ~ I~ o . , p", H
.. K~ ' ' IP .P O ~ ~J t1 t~ o 1- o a~ Ul tsl ~ ~ , OD . . . . ~ I J ~3 1-- a~ ~ Iv co ul (A~ O W o ~ O a~ I ~ ;' ' ~ I h~ ' :
~ ~ ~ ' - ' : ' ~ ~ ~ "'"' ~' t~ ~ t~ ,', ', "
,p ~ o <S~ ` ~ ~ ..
1~ 0 CO ~,n ~ ~1 ~n ~1 ~ 13 1 ~1 ~ H . .
. ~l . . . . . . . . . . tD ~ m ~ ~ H
Ul Ip ~) ~I I.A) ~ O .IP O ~ ~I ~.n C~ ~) - l~ I I .
~ ~ .
~ ~ ~ ;

(~ t~ ::
~ ~ O 1~ 0 ~:
P ~ O O ~ I ~ '.
o ~p ~n O ~] ' .
~1 ~ ., .

t~ ~ o a~
CO . ~ I W I -: ' - . ; ~,~ .
~, , .

1~45~6~
Fro~ ~he aho~e data ~t ~ en that some. o~ the catal~5 t~ of the present Inyent~n. ~a~ple~ 1 and 2~ are part-icularly acti~e for the production o~ C3 and C4 hydrocarbons ~oth saturated and ole~inicl. Furthermore, it is noted that the coke selectivity of our present catalysts is substantially better than that of the prior art comparison catalysts. Certain ~:~
compositions sho~ also ~etter gasoline selecti~ity than the reference catalyst CSample 6~
EXAMPLE II`
1~A. The sample o~ CaA zeolite used in the tests was a commercial product ~rom Davi~on. Chemical Co. It contained 18.1% Ca and had a surface area of 643 m2~g.
B. Various amounts of CaA as described above were compounded into catalyst using the technique set forth in Example I ~C.~ a~ove. The RE-H-Y, matrix components and , test conditions were the same as set forth in Example I.
The results are summarized in Table III below~

"

,.. . .
.: .

~, .

:

10~5~9 :~
O Ul Ul ~ ~ .P I ~ ~ ) ~ O O t~
+ + O O + +~ t~ 11 11 `~S 1-- 1 3 j~
~ ~4 ~ ~ O ` O ~ rD I 1-O O O ~ ~ O O .' dP
;~ j j & ~ ; c c ~ ~ ~
n n ~ dP ~ (D -C ~ ~ S: d~ C C
~ .
~?~ I' ~.

o ~ ~ ',' ~ ' a~ . ~ o 1~ ~ o u~ I t~ ~ .
~n ~ 1-- ~ ~ ~ ~ 1- ~I cn ~ o o 1-- 1 P~' .' It ~' w ~v o ~ ~ ~
~ o o~ ~ ~ ~3 o ~ l ~
co . . . . . . . . . . a~ m Pi ~o ~n o ~ ~ o o ~ O ~

o ~ a~ ~ ~ ~:q O ~ ~3. 0 ~ ~ O 1~ W ~ ~
o a~ ~o w ~ w ~ 1-- ~I ~I ~ ~ o co 1-- IJ I 1 w ~o ~ o .-1 r~ ~ o a~
00 W ~V O ~D al ~ ~I ~ ~ ~ o q ~D
00 . ~ . . . . . . a~ I w I u~
u r~ ~ o cn u~
w . ~ o ~ o~ o o~ w ~n ~ o 1~ W ~ W ~ O
w ; . . ~ .
, .

~5~69 F~om the ab~Qye~ it iS ~s~en that the cataly~ts o~ the ......
pr~sent inYent~On pusse~ ~upe~ r C3 - C4 hydrocar~on selectiv~ty and lo~ co~ producing properties.
EX~MPL~ IV
Another example of the ad~antage of using promoter mixtures over individual promoters~Ls;-~the-use of--a~RE-~I-Y/
Erionite mixture as promoter in a c.racking catalyst.
A. T~e RE-H-Y zeolIte was prepared a~ described in Example I.
1~ ~. H-erionite ~as obtained fro~ natural erionite by txeating the crushed mineral ~ith diluted hydrochloric acid under boiling, for ~bout 3 hours. The resulting material had a surface area of 36a m2/g and a S~02/A1203 ratio of 21.
C. Various amounts of H-erionite were compounded into the catalyst containing RE-H-Y, as described in Example I.
The m trix and test conditions are the same as thos~ described in previous examples.- The microactivity data obtained for a RE-H-Y/H-erionite (4:1~ mixture as shown in Table III
~Sample 5~.
2~ The data o~tained indicates that under the test con-ditions descri~ed, RE-H-Y/H-erionite-promoted catalyst provide high activity and an improved gasoline and coke selectivity over RE-H-Y or CREY promoted catalysts.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for the catalytic cracking of hydrocarbons which comprises contacting a hydrocarbon feedstock with a catalyst comprising (a) rare earth-hydrogen type Y zeolite, (b) a second zeolite consisting of exchanged mordenite having the general formula M-mordenite wherein M is selected from the group consisting of hydrogen, rare earth, cobalt, nickel and group II cations, under catalytic cracking conditions and recovering the products formed thereby.

2. The method according to Claim 1 wherein the cracking conditions comprise a temperature of 700-1200°F, a catalyst oil ratio of 0.5 to 30 and a contact time of 0.5 seconds to 10 minutes.

3. The method according to Claim 1 wherein the cracking conditions comprise a temperature 800-1050°F, a catalyst to oil ratio of 3-8 and a contact time of 10 seconds to 5 minutes.

4. The method according to Claim 1 wherein the feedstock is a gas oil boiling between 400 and 1050°F.

5. The process according to Claim 1 wherein the catalyst is a blend of about 5 to 15 weight percent of the zeolitic component and about 95 to 85 weight percent of an amorphous silica alumina component.