Molecular sieve abstract
This invention is directed to a hardened molecular sieve catalyst
composition, a method of making the composition and a method of
using the composition. The catalyst composition is made by mixing
together molecular sieve, liquid, and an effective hardening amount
of a dried molecular sieve catalyst to form a slurry. The slurry
is dried, and then calcined to form the hardened molecular sieve
catalyst composition. The hardened molecular sieve catalyst is highly
attrition resistant.
Molecular sieve claims
1. A method of making a hardened molecular sieve catalyst composition,
the method comprising the steps of: a) mixing together molecular
sieve, liquid, and an effective hardening amount of dried molecular
sieve catalyst to form a slurry of solids and liquid; b) drying
the slurry; and c) calcining the dried slurry to form the hardened
molecular sieve catalyst composition.
2. The method of claim 1 wherein binder is included in the mixing
of step a) to form the slurry.
3. The method of claim 2 wherein the binder is an inorganic oxide
sol.
4. The method of claim 3 wherein the inorganic oxide sol is an
alumina-containing sol.
5. The method of claim 1 wherein matrix material is included in
the mixing of step a) to form the slurry.
6. The method of claim 5 wherein the matrix material is clay.
7. The method of claim 1 wherein the dried molecular sieve is
in an amount effective to form a hardened molecular sieve catalyst
having an ARI of not greater than 0.6 wt %/hr upon calcining.
8. The method of claim 7 wherein the dried molecular sieve is
in an amount effective to form a hardened molecular sieve catalyst
having an ARI of not greater than 0.5 wt %/hr upon calcining.
9. The method of claim 8 wherein the dried molecular sieve is
in an amount effective to form a hardened molecular sieve catalyst
having an ARI of not greater than 0.4 wt %/hr upon calcining.
10. The method of claim 1 wherein from 2 wt % to 98 wt % of the
solids in the slurry, based on total weight of solids in the slurry,
is dried molecular sieve catalyst.
11. The method of claim 10 wherein from 15 wt % to 80 wt % of
the solids in the slurry, based on total weight of solids in the
slurry, is dried molecular sieve catalyst.
12. The method of claim 11 wherein from 20 wt % to 40 wt % of
the solids in the slurry, based on total weight of solids in the
slurry, is dried molecular sieve catalyst.
13. The method of claim 12 wherein from 20 wt % to 30 wt % of
the solids in the slurry, based on total weight of solids in the
slurry, is dried molecular sieve catalyst.
14. The method of claim 1 wherein from 10 wt % to 93 wt % of the
solids in the slurry, based on total weight of solids in the slurry,
is molecular sieve.
15. The method of claim 1 wherein the molecular sieve mixed in
step a) is selected from the group consisting of SAPO-5 SAPO-8
SAPO-11 SAPO-16 SAPO-17 SAPO-18 SAPO-20 SAPO-31 SAPO-34 SAPO-35
SAPO-36 SAPO-37 SAPO-40 SAPO-41 SAPO-42 SAPO-44 SAPO-47 SAPO-56
ALPO-5 ALPO-11 ALPO-18 ALPO-31 ALPO-34 ALPO-36 ALPO-37 ALPO-46
metal containing molecular sieves thereof, and mixtures thereof.
16. The method of claim 1 wherein the dried molecular sieve catalyst
mixed in step a) contains molecular sieve selected from the group
consisting of SAPO-5 SAPO-8 SAPO-11 SAPO-16 SAPO-17 SAPO-18
SAPO-20 SAPO-31 SAPO-34 SAPO-35 SAPO-36 SAPO-37 SAPO-40 SAPO-41
SAPO-42 SAPO-44 SAPO-47 SAPO-56 ALPO-5 ALPO-11 ALPO-18 ALPO-31
ALPO-34 ALPO-36 ALPO-37 ALPO-46 metal containing molecular sieves
thereof, and mixtures thereof.
17. A method of making a hardened molecular sieve catalyst composition,
the method comprising the steps of: a) mixing together molecular
sieve and dried molecular sieve catalyst to form a slurry of solids
and liquid, wherein from 2 wt % to 98 wt % of the solids in the
slurry, based on total weight of solids in the slurry, is dried
molecular sieve catalyst; b) drying the slurry; and c) calcining
the dried slurry to form the hardened molecular sieve catalyst composition.
18. The method of claim 17 wherein from 25 wt % to 80 wt % of
the solids in the slurry, based on total weight of solids in the
slurry, is dried molecular sieve catalyst.
19. The method of claim 18 wherein from 20 wt % to 40 wt % of
the solids in the slurry, based on total weight of solids in the
slurry, is dried molecular sieve catalyst.
20. The method of claim 19 wherein from 20 wt % to 30 wt % of
the solids in the slurry, based on total weight of solids in the
slurry, is dried molecular sieve catalyst.
21. The method of claim 17 wherein binder is included in the mixing
of step a) to form the slurry.
22. The method of claim 21 wherein the binder is an inorganic
oxide sol.
23. The method of claim 22 wherein the inorganic oxide sol is
an alumina-containing sol.
24. The method of claim 17 wherein matrix material is included
in the mixing of step a) to form the slurry.
25. The method of claim 24 wherein the matrix material is clay.
26. The method of claim 17 wherein the calcined, hardened molecular
sieve catalyst has an ARI of not greater than 0.6 wt %/hr.
27. The method of claim 26 wherein the calcined, hardened molecular
sieve catalyst has an ARI of not greater than 0.5 wt %/hr.
28. The method of claim 27 wherein the calcined hardened molecular
sieve catalyst has an ARI of not greater than 0.4 wt %/hr.
29. The method of claim 17 wherein from 10 wt % to 93 wt % of
the solids in the slurry, based on total weight of solids in the
slurry, is molecular sieve.
30. The method of claim 17 wherein the molecular sieve mixed in
step a) is selected from the group consisting of SAPO-5 SAPO-8
SAPO-11 SAPO-16 SAPO-17 SAPO-18 SAPO-20 SAPO-31 SAPO-34 SAPO-35
SAPO-36 SAPO-37 SAPO-40 SAPO-41 SAPO-42 SAPO-44 SAPO-47 SAPO-56
ALPO-5 ALPO-11 ALPO-18 ALPO-31 ALPO-34 ALPO-36 ALPO-37 ALPO-46
metal containing molecular sieves thereof, and mixtures thereof.
31. The method of claim 17 wherein the dried molecular sieve catalyst
mixed in step a) contains molecular sieve selected from the group
consisting of SAPO-5 SAPO-8 SAPO-11 SAPO-16 SAPO-17 SAPO-18
SAPO-20 SAPO-31 SAPO-34 SAPO-35 SAPO-36 SAPO-37 SAPO-40 SAPO-41
SAPO-42 SAPO-44 SAPO-47 SAPO-56 ALPO-5 ALPO-11 ALPO-18 ALPO-31
ALPO-34 ALPO-36 ALPO-37 ALPO-46 metal containing molecular sieves
thereof, and mixtures thereof.
32. A process for making olefin, the process comprising the steps
of: a) circulating a molecular sieve catalyst having an ARI of not
greater than 0.6 wt %/hr through a reactor system for at least 4
months; and b) contacting the circulating molecular sieve catalyst
with oxygenate to convert the oxygenate to olefin.
33. The process of claim 32 wherein the molecular sieve catalyst
has an ARI of not greater than 0.5 wt %/hr.
34. The process of claim 33 wherein the molecular sieve catalyst
has an ARI of not greater than 0.4 wt %/hr.
35. The process of claim 32 wherein the molecular sieve catalyst
contains SAPO molecular sieve.
36. The process of claim 32 further comprising contacting the
olefin with a polymer forming catalyst to form polyolefin.
Molecular sieve description
FIELD OF THE INVENTION
[0001] This invention relates to attrition resistant molecular
sieve catalysts. In particular, this invention relates to attrition
resistant molecular sieve catalysts that contain silicoaluminophosphate
(SAPO) molecular sieve.
BACKGROUND OF THE INVENTION
[0002] A molecular sieve is generally a microporous structure composed
of either crystalline aluminosilicate, belonging to a class of materials
known as zeolites, or crystalline aluminophosphates, or crystalline
silicoaluminophosphates. Molecular sieves can be made by hydrothermal
crystallization from a reaction mixture comprising reactive sources
of silicon and/or aluminum and/or phosphorous containing compounds,
usually in the presence of one or several organic amines or quaternary
ammonium salts as structure directing agents, also known as templates.
[0003] Molecular sieve catalysts are compositions made of molecular
sieve particles bound together to form particles larger than the
molecular sieve components. The molecular sieve catalyst particles
can also include other components such as binders, fillers, like
clay, and optionally other catalytically active agents such as rare
earth metal oxides, transition metal oxides, or noble metal components.
[0004] Conventional methods of making molecular sieve catalyst
particles include mixing together molecular sieve and binder, as
well as other optional components such as fillers and other catalytic
components. The mixture is typically stirred in solution to form
a slurry, and the slurry is dried to form molecular sieve catalyst
particles. Following drying, the particles are calcined to harden,
as well as activate, the catalyst particles.
[0005] For example, U.S. Pat. No. 6509290 B1 (Vaughn et al.)
discloses a method of making molecular sieve catalyst, the catalyst
containing molecular sieve attrition particles and virgin molecular
sieve. The attrition particles are essentially broken particles
that have been recycled from a catalyst manufacture process or a
reaction system. The method involves mixing together a molecular
sieve, virgin binders and fillers, spray dried attrition particles
or clumps, and non-virgin attrition particles from a reaction unit.
The mixture is dried to form finished catalyst particles. To add
strength to the finished catalyst particles, the attrition particles
are substantially free of coke.
[0006] U.S. Pat. No. 6153552 (Wachter et al.) describes another
method for making molecular sieve catalyst. The method involves
mixing together a molecular sieve and an alumina sol, the alumina
sol being made in solution and maintained at a pH of 2 to 10. The
mixture is then spray dried and calcined. The calcined product is
reported to be relatively hard, i.e., attrition resistant.
[0007] Certain catalytic reaction processes, particularly processes
which convert oxygenates to olefins, require very hard molecular
sieve catalyst compositions to survive the rigorous commercial scale
reaction conditions over a relatively long period of time. Conventional
methods of making molecular sieve catalysts fail to consistently
achieve an appropriate hardness for effective commercial scale use.
Additional methods are, therefore, needed for the manufacture of
molecular sieve catalyst particles that are sufficiently hard to
withstand rigorous commercial scale reaction conditions.
SUMMARY OF THE INVENTION
[0008] In one aspect, this invention provides a method for manufacturing
molecular sieve catalyst particles that are sufficiently hard such
that the catalyst can be used in commercial scale reaction systems
for up to several months. Because the particles are of such hardness,
they are strongly resistant to attrition, and can survive operations
in systems such as fluidized bed systems. This is a particular advantage
in riser reactor type fluidized bed systems, where the catalyst
is circulated throughout the system at relatively high velocities
and at relatively high temperatures. Because the particles are resistant
to attrition, they can be left in the reaction system for extended
periods of time.
[0009] In one aspect, this invention provides a method of making
a hardened molecular sieve catalyst composition. In one embodiment,
the method comprises mixing together molecular sieve, liquid, and
an effective hardening amount of dried molecular sieve catalyst
to form a slurry of solids and liquid. The slurry is dried, and
the dried material is calcined to form the hardened molecular sieve
catalyst composition.
[0010] In another embodiment, the invention provides a method,
which comprises mixing together molecular sieve and dried molecular
sieve catalyst to form a slurry of solids and liquid, wherein from
2 wt % to 98 wt % of the solids in the slurry, based on total weight
of solids in the slurry, is dried molecular sieve catalyst. The
slurry is dried, and the dried slurry is calcined to form the hardened
molecular sieve catalyst composition.
[0011] In anther embodiment, the process comprises circulating
a molecular sieve catalyst having an ARI of not greater than 0.6
wt %/hr through a reactor system for at least 4 months. During the
process, the circulating molecular sieve catalyst is contacted with
oxygenate to convert the oxygenate to olefin.
[0012] In one embodiment of the invention, binder, and optionally
matrix material, are mixed with the molecular sieve and dried molecular
sieve catalyst to form the slurry. Preferably, the binder is an
inorganic oxide sol, more preferaby an alumina-containing sol. Preferably,
the matrix material is clay.
[0013] The dried molecular sieve catalyst that is added to form
the slurry acts to substantially increase the hardness or attrition
resistance of the finished or calcined molecular sieve catalyst.
Preferably, this finished or hardened molecular sieve catalyst has
an ARI of not greater than 0.6 wt %/hr upon calcining, more preferably
not greater than 0.5 wt %/hr upon calcining, and most preferably
not greater than 0.4 wt %/hr upon calcining.
[0014] In one embodiment, from 2 wt % to 98 wt % of the solids
in the slurry, based on total weight of solids in the slurry, is
dried molecular sieve catalyst. Preferably, from 15 wt % to 80 wt
% of the solids in the slurry, based on total weight of solids in
the slurry, is dried molecular sieve catalyst. More preferably,
from 20 wt % to 40 wt % of the solids in the slurry, based on total
weight of solids in the slurry, is dried molecular sieve catalyst;
and most preferably, from 20 wt % to 30 wt % of the solids in the
slurry, based on total weight of solids in the slurry, is dried
molecular sieve catalyst.
[0015] In another embodiment, from 10 wt % to 93 wt % of the solids
in the slurry, based on total weight of solids in the slurry, is
molecular sieve. Preferably, the molecular sieve is selected from
the group consisting of SAPO-5 SAPO-8 SAPO-11 SAPO-16 SAPO-17
SAPO-18 SAPO-20 SAPO-31 SAPO-34 SAPO-35 SAPO-36 SAPO-37 SAPO-40
SAPO-41 SAPO-42 SAPO-44 SAPO-47 SAPO-56 ALPO-5 ALPO-11 ALPO-18
ALPO-31 ALPO-34 ALPO-36 ALPO-37 ALPO-46 metal containing molecular
sieves thereof, and mixtures thereof. Also preferably, the dried
molecular sieve catalyst contains molecular sieve selected from
the group consisting of SAPO-5 SAPO-8 SAPO-11 SAPO-16 SAPO-17
SAPO-18 SAPO-20 SAPO-31 SAPO-34 SAPO-35 SAPO-36 SAPO-37 SAPO-40
SAPO-41 SAPO-42 SAPO-44 SAPO-47 SAPO-56 ALPO-5 ALPO-11 ALPO-18
ALPO-31 ALPO-34 ALPO-36 ALPO-37 ALPO-46 metal containing molecular
sieves thereof, and mixtures thereof.
BRIEF DESCRIPTION OF THE DRAWING
[0016] An example of one embodiment of this invention is shown
in the attached FIGURE, wherein the FIGURE shows the hardness effects
of using dried molecular sieve catalyst as a slurry component in
the manufacture of a final product catalyst.
DETAILED DESCRIPTION OF THE INVENTION
I. Hardened Molecular Sieve Catalyst
[0017] This invention is directed to hardened molecular sieve catalyst,
methods of making the catalyst, and methods of using the catalyst.
The molecular sieve catalyst is significantly harder than conventional
molecular sieve catalysts, and can be used over an extended period
of time, as it is highly resistant to attrition. For example, in
fluidized bed systems, particularly fast fluidized bed systems,
it is desirable to have hard catalysts so that they will not break
apart due to forces encountered during operation, thus shortening
useful catalyst life. It is particularly desirable in systems capable
of converting oxygenates to olefins to be able to circulate catalyst
throughout the catalyst system for up to at least 4 6 or 8 months,
perhaps longer, without encountering significant catalyst attrition.
The catalyst of this invention can meet such rigorous requirements.
[0018] In one embodiment, the hardened molecular sieve catalyst
is characterized according to an Attrition Rate Index (ARI). The
ARI is used over other measurement methods, since many other methods
are not sufficient to measure very highly attrition resistant molecular
sieve catalysts, such as those made according to this invention.
[0019] The ARI methodology is similar to the conventional Davison
Index method. The smaller the ARI, the more resistant to attrition;
hence, the harder the catalyst. The ARI is measured by adding 6.0.+-.0.1
g of catalyst, having a particle size ranging from 53 to 125 microns,
into a hardened steel attrition cup. Approximately 23700 scc/min
of nitrogen gas is bubbled through a water-containing bubbler to
humidify the nitrogen. The wet nitrogen is passed through the attrition
cup, and exits the attrition apparatus through a porous fiber thimble.
The flowing nitrogen removes the finer particles, with the larger
particles being retained in the cup. The porous fiber thimble separates
the fine catalyst particles from the nitrogen that exits through
the thimble. The fine particles remaining in the thimble represent
catalyst that has broken apart through attrition.
[0020] The nitrogen flow passing through the attrition cup is maintained
for 1 hour. Fines collected in the thimble are removed from the
unit, and a new thimble installed. The catalyst left in the attrition
unit is attrited for an additional 3 hours, under the same gas flow
and moisture levels. The fines collected in the thimble are recovered.
The collection of fine catalyst particles separated by the thimble
after the first hour are weighed. The amount in grams of fine particles
divided by the original amount of catalyst charged to the attrition
cup expressed on per hour basis is the ARI, in wt %/hr.
ARI=[C/(B+C)/D].times.100%
[0021] wherein
[0022] B=weight of catalyst left in the cup after the attrition
test;
[0023] C=weight of collected fine catalyst particles after the
first hour of attrition treatment; and
[0024] D=duration of treatment in hours after the first hour attrition
treatment.
[0025] The hardened molecular sieve catalyst of this invention
has an ARI of not greater than about 0.6 wt %/hr. Preferably, the
hardened molecular sieve catalyst has an ARI of not greater than
about 0.5 wt %/hr, more preferably not greater than about 0.4 wt
%/hr.
[0026] In one embodiment of the invention, the hardened molecular
sieve catalyst has a particle size distribution such that not greater
than about 10 wt % of the catalyst particles have an average diameter
less than or equal to 20 .mu.m. Preferably, the hardened molecular
sieve catalyst has a particle size distribution such that not greater
than about 5 wt % of the catalyst particles have an average diameter
less than or equal to 20 .mu.m; more preferably not greater than
about 2 wt % of the catalyst particles have an average diameter
less than or equal to 20 .mu.m.
[0027] In another embodiment, the catalyst composition is comprised
of catalyst particles in which not greater than about 10 wt % of
the catalyst particles have an average diameter greater than or
equal to about 250 .mu.m. Preferably, not greater than about 5 wt
% of the catalyst particles have an average diameter greater than
or equal to about 250 .mu.m; more preferably not greater than about
2 wt % of the catalyst particles have an average diameter greater
than or equal to 250 .mu.m.
[0028] In another embodiment of the invention, the hardened molecular
sieve catalyst particles have a particle size distribution particularly
suited for use in fluidized bed reaction systems. For example, in
one embodiment, the hardened molecular sieve catalyst has a particle
size distribution in .mu.m of 2<d.sub.10<50; 30<d.sub.50<120;
and 50<d.sub.90<250 wherein d.sub.10 is the average diameter
in which the cumulative volume of the sample reaches 10% of the
total, d.sub.50 is the average diameter in which the cumulative
volume of the sample reaches 50% of the total, and d.sub.90 is the
average diameter in which the cumulative volume of the sample reaches
90% of the total. Preferably, the hardened molecular sieve catalyst
has a particle size distribution in .mu.m of 5<d.sub.10<45;
40<d.sub.50<100; and 70<d.sub.90<200; more preferably,
a particle size distribution in .mu.m of 10<d.sub.10<40; 50<d.sub.50<100;
and 90<d.sub.90<150.
II. Method of Making the Hardened Molecular Sieve Catalyst
[0029] A. General Method of Making
[0030] The catalyst of this invention is manufactured by first
mixing together various virgin catalyst components, liquid, and
an effective hardening amount of a dried molecular sieve catalyst
to form a slurry of solids and liquid. The slurry is then dried
so as to form a hardened molecular sieve catalyst. The effective
hardening amount of dried molecular catalyst is an amount that significantly
enhances the hardness of a calcined final product catalyst (i.e.,
formulated molecular sieve catalyst).
[0031] B. Virgin Catalyst Components
[0032] According to this invention virgin catalyst components comprise
any component materials conventionally used in the manufacture of
formulated molecular sieve catalyst. Such components include molecular
sieve, matrix material (including filler material and catalytically
active components other than molecular sieve) and binder.
[0033] 1. Molecular Sieves
[0034] Any molecular sieve, which has not been formulated into
a catalyst composition, is included as one of the virgin catalyst
components of this invention. Molecular sieves have various chemical,
physical, and framework characteristics, and have been classified
by the Structure Commission of the International Zeolite Association
according to the rules of the IUPAC Commission on Zeolite Nomenclature.
A framework-type describes the topology and connectivity of tetrahedrally
coordinated atoms constituting the framework, and makes an abstraction
of the specific properties for those materials. Framework-type zeolite
and zeolite-type molecular sieves for which a structure has been
established, are assigned a three letter code and are described
in the Atlas of Zeolite Framework Types, 5th edition, Elsevier,
London, England (2001), which is herein fully incorporated by reference.
[0035] Crystalline molecular sieve materials all have a 3-dimensional,
four-connected framework structure of corner-sharing TO.sub.4 tetrahedra,
where T is any tetrahedrally coordinated cation. Molecular sieves
are typically described in terms of the size of the ring that defines
a pore, where the size is based on the number of T atoms in the
ring. Other framework-type characteristics include the arrangement
of rings that form a cage, and when present, the dimension of channels,
and the spaces between the cages. See van Bekkum, et al., Introduction
to Zeolite Science and Practice, Second Completely Revised and Expanded
Edition, Volume 137 pages 1-67 Elsevier Science, B.V., Amsterdam,
Netherlands (2001).
[0036] Non-limiting examples of molecular sieves are the small
pore molecular sieves, AEI, AFT, APC, ATN, ATT, ATV, AWW, BIK, CAS,
CHA, CHI, DAC, DDR, EDI, ERI, GOO, KFI, LEV, LOV, LTA, MON, PAU,
PHI, RHO, ROG, THO, and substituted forms thereof; the medium pore
molecular sieves, AFO, AEL, EUO, HEU, FER, MEL, MFI, MTW, MTT, TON,
and substituted forms thereof, and the large pore molecular sieves,
EMT, FAU, and substituted forms thereof. Other molecular sieves
include ANA, BEA, CFI, CLO, DON, GIS, LTL, MER, MOR, MWW and SOD.
Non-limiting examples of preferred molecular sieves, particularly
for converting an oxygenate containing feedstock into olefin(s),
include AEL, AFY, BEA, CHA, EDI, FAU, FER, GIS, LTA, LTL, MER, MFI,
MOR, MTT, MWW, TAM and TON. In one preferred embodiment, the molecular
sieve of the invention has an AEI topology or a CHA topology, or
a combination thereof, most preferably a CHA topology.
[0037] Small, medium and large pore molecular sieves have from
a 4-ring to a 12-ring or greater framework-type. Typically, the
molecular sieves employed herein have 8-, 10- or 12-ring structures
and an average pore size in the range of from about 3 .ANG. to 15
.ANG.. More typically, the molecular sieves, preferably silicoaluminophosphate
molecular sieves, have 8-rings and an average pore size less than
about 5 .ANG., such as in the range of from 3 .ANG. to about 5 .ANG.,
for example from 3 .ANG. to about 4.5 .ANG., and particularly from
3.5 .ANG. to about 4.2 .ANG..
[0038] Molecular sieves used herein have a molecular framework
including at least [AlO.sub.4] and [PO.sub.4] tetrahedral units,
such as aluminophosphates (AlPO), and typically including at least
[AlO.sub.4] and [PO.sub.4] and [SiO.sub.4] tetrahedral units, such
as silicoaluminophosphates (SAPO). These silicon, aluminum, and
phosphorus based molecular sieves and metal-containing derivatives
thereof have been described in detail in numerous publications including
for example, U.S. Pat. No. 4567029 (MeAPO where Me is Mg, Mn,
Zn, or Co), U.S. Pat. No. 4440871 (SAPO), European Patent Application
EP-A-0 159 624 (ELAPSO where El is As, Be, B, Cr, Co, Ga, Ge, Fe,
Li, Mg, Mn, Ti or Zn), U.S. Pat. No. 4554143 (FeAPO), U.S. Pat.
Nos. 4822478 4683217 4744885 (FeAPSO), EP-A-0 158 975 and
U.S. Pat. No. 4935216 (ZnAPSO, EP-A-0 161 489 (CoAPSO), EP-A-0
158 976 (ELAPO, where EL is Co, Fe, Mg, Mn, Ti or Zn), U.S. Pat.
No. 4310440 (AlPO.sub.4), EP-A-0 158 350 (SENAPSO), U.S. Pat.
No. 4973460 (LiAPSO), U.S. Pat. No. 4789535 (LiAPO), U.S. Pat.
No. 4992250 (GeAPSO), U.S. Pat. No. 4888167 (GeAPO), U.S. Pat.
No. 5057295 (BAPSO), U.S. Pat. No. 4738837 (CrAPSO), U.S. Pat.
Nos. 4759919 and 4851106 (CrAPO), U.S. Pat. Nos. 4758419
4882038 5434326 and 5478787 (MgAPSO), U.S. Pat. No. 4554143
(FeAPO), U.S. Pat. No. 4894213 (AsAPSO), U.S. Pat. No. 4913888
(AsAPO), U.S. Pat. Nos. 4686092 4846956 and 4793833 (MnAPSO),
U.S. Pat. Nos. 5345011 and 6156931 (MnAPO), U.S. Pat. No. 4737353
(BeAPSO), U.S. Pat. No. 4940570 (BeAPO), U.S. Pat. Nos. 4801309
4684617 and 4880520 (TiAPSO), U.S. Pat. Nos. 4500651 4551236
and 4605492 (TiAPO), U.S. Pat. Nos. 4824554 4744970 (CoAPSO),
U.S. Pat. No. 4735806 (GaAPSO) EP-A-0 293 937 (QAPSO, where Q
is framework oxide unit [QO.sub.2]), as well as U.S. Pat. Nos. 4567029
4686093 4781814 4793984 4801364 4853197 4917876
4952384 4956164 4956165 4973785 5241093 5493066
and 5675050 all of which are herein fully incorporated by reference.
[0039] Other molecular sieves include those described in R. Szostak,
Handbook of Molecular Sieves, Van Nostrand Reinhold, New York, N.Y.
(1992), which is herein fully incorporated by reference.
[0040] The more preferred molecular sieves are SAPO molecular sieves,
and metal-substituted SAPO molecular sieves. Suitable metal substituents
are alkali metals of Group IA of the Periodic Table of Elements,
an alkaline earth metals of Group IIA of the Periodic Table of Elements,
a rare earth metals of Group IIIB, including the Lanthanides: lanthanum,
cerium, praseodymium, neodymium, samarium, europium, gadolinium,
terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium;
and scandium or yttrium of the Periodic Table of Elements, transition
metals of Groups IVB, VB, VIB, VIIB, VIIIB, and IB of the Periodic
Table of Elements and mixtures of any of these metal species. In
one embodiment, the metal is selected from the group consisting
of Co, Cr, Cu, Fe, Ga, Ge, Mg, Mn, Ni, Sn, Ti, Zn and Zr, and mixtures
thereof. The metal atoms may be inserted into the framework of a
molecular sieve through a tetrahedral unit, such as [MeO.sub.2],
and carry a net charge depending on the valence state of the metal
substituent. For example, in one embodiment, when the metal substituent
has a valence state of +2 +3 +4 +5 or +6 the net charge of
the tetrahedral unit is between -2 and +2.
[0041] In one embodiment, the molecular sieve, as described in
many of the U.S. Patents mentioned above, is represented by the
empirical formula, on an anhydrous basis:
mR:(M.sub.xAl.sub.yP.sub.z)O.sub.2
[0042] wherein R represents at least one templating agent, preferably
an organic templating agent; m is the number of moles of R per mole
of (M.sub.xAl.sub.yP.sub.z)O.sub.2 and m has a value from 0 to 1
preferably 0 to 0.5 and most preferably from 0 to 0.3; x, y, and
z represent the mole fraction of Al, P and M as tetrahedral oxides,
where M is a metal selected from one of Group IA, IIA, IB, IIIB,
IVB, VB, VIB, VIIB, VIIIB and Lanthanide's of the Periodic Table
of Elements. Preferably M is selected from one of the group consisting
of Si, Co, Cr, Cu, Fe, Ga, Ge, Mg, Mn, Ni, Sn, Ti, Zn and Zr. In
an embodiment, m is greater than or equal to 0.2 and x, y and z
are greater than or equal to 0.01. In another embodiment, m is greater
than 0.1 to about 1 x is greater than 0 to about 0.25 y is in
the range of from 0.4 to 0.5 and z is in the range of from 0.25
to 0.5 more preferably m is from 0.15 to 0.7 x is from 0.01 to
0.2 y is from 0.4 to 0.5 and z is from 0.3 to 0.5.
[0043] Where the molecular sieve is a silicoaluminophosphate or
metal-containing silicoaluminophosphate, the SAPO typically has
a Si/Al ratio less than 0.65 such as less than 0.40 for example
less than 0.32 and particularly less than 0.20. In one embodiment
the molecular sieve has a Si/Al ratio in the range of from about
0.65 to about 0.10 such as from about 0.40 to about 0.10 for example
from about 0.32 to about 0.10 and particularly from about 0.32
to about 0.15.
[0044] Non-limiting examples of SAPO and AlPO molecular sieves
useful herein are selected from the group consisting of SAPO-5
SAPO-8 SAPO-11 SAPO-16 SAPO-17 SAPO-18 SAPO-20 SAPO-31 SAPO-34
SAPO-35 SAPO-36 SAPO-37 SAPO-40 SAPO-41 SAPO-42 SAPO-44 SAPO-47
SAPO-56 AlPO-5 AlPO-11 AlPO-18 AlPO-31 AlPO-34 AlPO-36 AlPO-37
AlPO-46 metal containing molecular sieves thereof, and mixtures
thereof. Of these, particularly useful molecular sieves are selected
from the group consisting of SAPO-18 SAPO-34 SAPO-35 SAPO-44
SAPO-56 AlPO-18 AlPO-34 metal containing derivatives thereof,
and mixtures thereof. More preferably the molecular sieves are selected
from the group consisting of SAPO-18 SAPO-34 AlPO-34 AlPO-18
metal containing derivatives thereof, and mixtures thereof; and
most preferably selected from the group consisting of SAPO-34 AlPO-18
metal containing derivatives thereof and mixtures thereof.
[0045] In one embodiment, the molecular sieve is an intergrowth
material having two or more distinct crystalline phases within one
molecular sieve composition. In particular, intergrowth molecular
sieves are described in U.S. Patent Application Publication No.
2002-0165089 and International Publication No. WO 98/15496 published
Apr. 16 1998 both of which are herein fully incorporated by reference.
For example, SAPO-18 AlPO-18 and RUW-18 have an AEI framework-type,
and SAPO-34 has a CHA framework-type. Thus the molecular sieve used
herein may comprise at least one intergrowth phase of AEI and CHA
framework-types, especially where the ratio of CHA framework-type
to AEI framework-type, as determined by the DIFFaX method disclosed
in U.S. Patent Application Publication No. 2002-0165089 is greater
than 1:1.
[0046] 2. Matrix Materials
[0047] Matrix materials are optionally included in the slurry used
to make the hardened molecular sieve catalyst of this invention.
Such materials are typically effective as thermal sinks assisting
in shielding heat from the catalyst composition, for example, during
regeneration. They can further act to density the catalyst composition,
increase catalyst strength such as crush strength and attrition
resistance, and to control the rate of conversion in a particular
process. Non-limiting examples of matrix materials include one or
more of rare earth metals, metal oxides including titania, zirconia,
magnesia, thoria, beryllia, quartz, silica or sols, and mixtures
thereof; for example, silica-magnesia, silica-zirconia, silica-titania,
silica-alumina and silica-alumina-thoria.
[0048] In one embodiment, matrix materials are natural clays, such
as those from the families of montmorillonite and kaolin. These
natural clays include kaolins known as, for example, Dixie, McNamee,
Georgia and Florida clays. Non-limiting examples of other matrix
materials include: halloysite, kaolinite, dickite, nacrite, or anauxite.
Optionally, the matrix material, preferably any of the clays, are
calcined, acid treated, and/or chemical treated before being used
as a slurry component. Under the optional calcination treatment,
the matrix material will still be considered virgin material as
long as the material has not been previously used in a catalyst
formulation.
[0049] In a particular embodiment, the matrix material is a clay
or a clay-type composition, preferably a clay or clay-type composition
having a low iron or titanium content, and most preferably the matrix
material is kaolin. Kaolin has been found to form a pumpable, high
solid content slurry; it has a low fresh surface area, and it packs
together easily due to its platelet structure.
[0050] Preferably, the matrix material, particularly clay, and
preferably kaolin, has an average particle size of from about 0.05
.mu.m to about 0.75 .mu.m; more preferably from about 0.1 .mu.m
to about 0.6 .mu.m. It is also desirable that the matrix material
have a d.sub.90 particle size distribution of less than about 1.5
.mu.m, preferably less than about 1 .mu.m.
[0051] 3. Binders
[0052] Binders are optionally included in the slurry used to make
the hardened molecular sieve catalyst of this invention. Such materials
act like glue, binding together the molecular sieve and other materials,
to form a formulated catalyst composition. Non-limiting examples
of binders include various types of inorganic oxide sols such as
hydrated aluminas, silicas, and/or other inorganic oxide sols. In
one embodiment of the invention, the binder is an alumina-containing
sol, preferably aluminium chlorohydrate. Upon heating, the inorganic
oxide sol, is converted into an inorganic oxide matrix component,
which is particularly effective in forming a hardened molecular
sieve catalyst composition. For example, an alumina sol will convert
to an aluminium oxide matrix following heat treatment.
[0053] Aluminium chlorohydrate, a hydroxylated aluminium based
sol containing a chloride counter ion, also known as aluminium chlorohydrol,
has the general formula Al.sub.mO.sub.n(OH).sub.oCl.sub.p.x(H.sub.2O),
wherein m is 1 to 20 n is 1 to 8 o is 5 to 40 p is 2 to 15 and
x is 0 to 30. In one embodiment, the binder is Al.sub.13O.sub.4(OH).sub.24Cl.sub-
.7.12(H.sub.2O) as is described in G. M. Wolterman, et al., Stud.
Surf Sci. and Catal., 76 pages 105-144 Elsevier, Amsterdam, 1993
which is herein incorporated by reference. In another embodiment,
one or more binders are present in combination with one or more
other non-limiting examples of alumina materials such as aluminium
oxyhydroxide, .gamma.-alumina, boehmite and transitional aluminas
such as .alpha.-alumina, .beta.-alumina, .gamma.-alumina, .delta.-alumina,
.epsilon.-alumina, .kappa.-alumina, and .rho.-alumina, aluminium
trihydroxide, such as gibbsite, bayerite, nordstrandite, doyelite,
and mixtures thereof.
[0054] In another embodiment, the binders are alumina sols, predominantly
comprising aluminium oxide, optionally including silicon. In yet
another embodiment, the binders are peptised alumina made by treating
alumina hydrates such as pseudobohemite, with an acid, preferably
a non-halogen acid, to prepare sols or aluminium ion solutions.
Non-limiting examples of commercially available colloidal alumina
sols include Nalco 8676 available from Nalco Chemical Co., Naperville,
Ill., and Nyacol AL20DW available from the Nyacol Nano Technology
Inc., Boston, Mass.
[0055] In one embodiment, the weight ratio of the binder to the
molecular sieve is in the range of from about 0.1 to 0.5 such as
in the range of from 0.1 to less than 0.5 for example in the range
of from 0.11 to 0.48 conveniently from 0.12 to about 0.45 typically
from 0.13 to less than 0.45 and particularly in the range of from
0.15 to about 0.4. In another embodiment, the weight ratio of the
binder to the molecular sieve is in the range of from 0.11 to 0.45
such as in the range of from about 0.12 to less than 0.40 for example
in the range of from 0.15 to about 0.35 and conveniently in the
range of from 0.2 to about 0.3.
[0056] Where the catalyst composition contains a binder and a matrix
omaterial, the weight ratio of the binder to the matrix material
is typically from 1:15 to 1:5 such as from 1:10 to 1:4 and particularly
from 1:6 to 1:5. The amount of binder is typically from about 2%
by weight to about 30% by weight, suh as from about 5% by weight
to about 20% by weight, and particularly from about 7% by weight
to about 15% by weight, based on the total weight of the binder,
the molecular sieve and matrix material. It has been found that
a higher sieve content and lower matrix content increases the molecular
sieve catalyst composition performance, whereas a lower sieve content
and higher matrix content improves the attrition resistance of the
composition.
[0057] In general, the amount of binder and/or matrix material
is such that the formulated molecular sieve catalyst composition
contains from about 1% to about 99%, such as from about 10% to about
90%, such as from about 10% to about 80%, for example from about
20% to about 70%, and conveniently from about 25% to about 60% by
weight of the molecular sieve based on the total weight of the molecular
sieve catalyst composition.
[0058] C. Dried Molecular Sieve Catalyst Component
[0059] The dried molecular sieve catalyst component is made using
the same virgin catalyst components described above (i.e., molecular
sieve, and optionally matrix material and binder), and can be prepared
according to conventional methods. For example, molecular sieve,
optionally binder and/or matrix material, are mixed with a liquid
to form a slurry. The slurry is then dried, preferably by spray
drying, to form a dried molecular sieve catalyst. Since, the dried
molecular sieve catalyst has not been calcined or used in any reaction
process, it has not been activated, and is considered virgin material.
The dried molecular sieve catalyst is then used as a catalyst component
to form the hardened molecular sieve catalyst composition of this
invention. Thus, the dried molecular sieve catalyst contains any
one or more of the molecular sieves described above, and optionally
any one or more of the matrix materials and/or binders described
above.
[0060] If binder is not used in making the dried molecular sieve
catalyst component, the dried molecular sieve catalyst is considered
a dried binderless catalyst component, and can be used in making
the hardened catalyst composition of this invention. If binder is
used, the amount of binder used to prepare the dried molecular sieve
catalyst component ranges from about 2% by weight to about 30% by
weight, based on the total weight of the binder, the molecular sieve,
and optionally included matrix material, excluding the liquid (i.e.,
after drying). Preferably the amount of binder used to prepare the
dried molecular sieve catalyst ranges from about 5% by weight to
about 20% by weight, more preferably from about 7% by weight to
about 15% by weight, based on the total weight of the binder, the
molecular sieve, and optionally included matrix material, excluding
the liquid (i.e., after drying).
[0061] In one embodiment, the slurry used to make the dried molecular
sieve catalyst component contains binder and matrix material at
a weight ratio of from 0:1 to 1:1. Preferably, the slurry used to
make the dried molecular sieve catalyst component contains binder
and matrix material at a weight ratio of from 1:15 to 1:2 more
preferably 1:10 to 1:2 and most preferably 1:6 to 1:1.
[0062] The liquid used to form the dried molecular sieve catalyst
component can be any liquid conventionally used in formulating molecular
sieve catalysts. Non-limiting examples of suitable liquids include
water, alcohol, ketones, aldehydes, esters, or a combination thereof.
Water is a preferred liquid.
[0063] The molecular sieve, and the optional matrix material and/or
binder, used in making the dried catalyst component may be combined
in the same or different liquid. Such components may be combined
in any order, i.e., together, simultaneously, sequentially, or a
combination thereof. In a preferred embodiment, the same liquid,
preferably water, is used.
[0064] In one embodiment, a slurry of the molecular sieve, and
optional binder and matrix materials, is mixed or milled to achieve
a uniform slurry of sub-particles. The slurry is then fed to a forming
unit that produces the dried molecular sieve catalyst composition.
The forming unit may be any conventional unit, such as a spray dryer,
pelletizer, extruder, granulator, etc. In a preferred embodiment,
the forming unit is spray dryer. Typically, the forming unit is
maintained at a temperature sufficient to remove a majority of the
liquid from the slurry.
[0065] When a spray dryer is used as the forming (or drying) unit,
typically, the slurry of the molecular sieve, and optional matrix
material and/or binder, is co-fed to the spray drying volume with
a drying gas. Conventional drying conditions can be used. Such conditions
include an average inlet temperature ranging from about 150.degree.
C. to about 550.degree. C., and an average outlet temperature ranging
from about 100.degree. C. to about 250.degree. C.
[0066] During spray drying, the slurry is passed through a nozzle
distributing the slurry into small droplets, resembling an aerosol
spray, into a drying chamber. Atomization is achieved by forcing
the slurry through a single nozzle or multiple nozzles with a pressure
drop in the range of from about 100 psia to about 1000 psia (about
690 kPaa to about 6895 kPaa). In another embodiment, the slurry
is co-fed through a single nozzle or multiple nozzles along with
an atomization fluid such as air, steam, flue gas, or any other
suitable gas.
[0067] In yet another embodiment, the slurry that is used to make
the dried catalyst component is directed to the perimeter of a spinning
wheel that distributes the slurry into small droplets. The size
of the droplets is controlled by one or more factors including slurry
viscosity, surface tension, flow rate, pressure, and temperature
of the slurry; the shape and dimension of the nozzle(s); or the
spinning rate of the wheel. These droplets are then dried in a co-current
or counter-current flow of air passing through a spray dryer to
form a partially, substantially or totally dried molecular sieve
catalyst composition. An example of a conventional spray drying
process is described in U.S. Pat. No. 4946814 which is incorporated
herein by reference.
[0068] For purposes of this invention, dried means that the mixture
used to form the dried molecular sieve catalyst has been heated
in a drying or forming unit, but has not been calcined. Calcined
catalysts are formed using a calcination process. The calcination
process is considered a combustion process that takes place at a
higher temperature than that of a drying process to combust or remove
template from the molecular sieve component, or a pyrolysis or thermal
decomposition process where the template molecules are disintegrated
into volatile compounds.
[0069] Dried also means that at least a portion of the liquid used
during the manufacture of the dried molecular sieve catalyst has
been removed. The process of manufacturing the dried molecular sieve
process is generally referred to as catalyst formulation, with the
dried catalyst generally being referred to as formulated catalyst.
The dried molecular sieve catalyst component optionally contains
structure directing molecules (i.e., templates).
[0070] In an embodiment of the invention, the dried molecular sieve
catalyst component contains template material. Template materials
are chemical compounds that are added during the molecular sieve
manufacturing process. During the formation of the molecular sieves
themselves, a lattice type chemical structure is formed. This lattice
type structure essentially wraps around the template material, with
the template material acting as a means of forming a pore structure
within the molecular sieve. The molecular sieve is ultimately formulated
into a finished catalyst, and activated for catalytic use, by calcining
or burning out the template. An elution process can also be used
to remove the template, although calcination is preferred. Once
the template is removed from the molecular sieve, a vast pore system
remains within the molecular sieve structure. The pore system pore
system is generally referred to as an intracrystalline pore system,
and has active catalytic sites open to the immediate environment.
[0071] Since the drying conditions used in forming the dried molecular
sieve catalyst component are less rigorous than the typical calcination
conditions, the molecular sieve components of the dried molecular
sieve catalyst preferably contains at least some of the original
template material or at least a portion of a thermally degraded
template. The remaining template or its thermal degradation product
will typically be effective in covering active catalyst sites of
the molecular sieve incorporated into the dried molecular sieve
catalyst component. Because the active catalyst sites are generally
covered by the template or a thermal degradation product of the
template, the active sites are not available for catalytic activity,
and the dried molecular sieve catalyst component is considered to
be in the non-active form.
[0072] Representative templates which can be included in the first
dried catalyst particles include tetraethyl ammonium salts, cyclopentylamine,
aminomethyl cyclohexane, piperidine, triethylamine, cyclohexylamine,
tri-ethyl hydroxyethylamine, morpholine, dipropylamine (DPA), pyridine,
isopropylamine and combinations thereof. Preferred templates are
triethylamine, cyclohexylamine, piperidine, pyridine, isopropylamine,
tetraethyl ammonium salts, dipropylamine, and mixtures thereof.
The tetraethylammonium salts include tetraethyl ammonium hydroxide
(TEAOH), tetraethyl ammonium phosphate, tetraethyl ammonium fluoride,
tetraethyl ammonium bromide, tetraethyl ammonium chloride, tetraethyl
ammonium acetate.
[0073] D. Making a Slurry of Virgin Catalyst Components, Liquid
and Dried Molecular Sieve Catalyst
[0074] Virgin catalyst components, liquid, and dried molecular
sieve are mixed together using conventional techniques to form a
slurry. They are mixed in any order. For example, the virgin catalyst
components and/or the dried molecular sieve catalyst can be added
to the liquid, the liquid can be added to the virgin catalyst components
or to the dried molecular sieve catalyst, and any remaining components
can be subsequently added. The mixture is thoroughly stirred to
form a slurry. The more thorough the stirring, the better the consistency
of the slurry. In this case, the slurry is also called the final
product slurry, since the final hardened catalyst will be made from
this slurry.
[0075] In one embodiment of the invention, the dried molecular
sieve catalyst is mixed with liquid to form a final product slurry.
The liquid used to make this slurry is the same type of liquid used
in making the dried molecular sieve catalyst component. Preferably,
the liquid is water. The final product slurry optionally includes
matrix material and binder as that used in making the slurry for
forming the dried molecular sieve catalyst.
[0076] The mixing of the final product slurry is preferably sufficient
to break larger dried molecular sieve catalyst particles included
in the slurry. In general, the more vigorous the mixing, the smaller
the dried molecular sieve catalyst particles formed in the slurry.
Mixing using high-shear mixers is preferred. In general, high-shear
mixers are capable of rotating at speeds of at least about 3000
rpms laboratory scale equivalent.
[0077] Solids particle size of the slurry can be indirectly determined
by measuring the viscosity of the slurry. In general, the higher
the viscosity, the smaller the solids particle size in the slurry.
The viscosity of the slurry should not be too high, so that mixing
is not effective in breaking apart large particles, or too low,
so that drying will not produce acceptable particle formation. Slurries
having too high of a viscosity tend to cause problems in the spray
dryer. For example, very high viscosity slurries tend to plug spray
nozzles or spinning wheels used in spray dryers to form the spray
dried materials. This plugging action can lead to the formation
of irregularly shaped spray dried particles.
[0078] In one embodiment, the final product slurry has a viscosity
of from about 100 cP (0.1 Pa/sec) to about 12500 cP (12.5 Pa/sec),
as measured using a Brookfield LV-DVE viscometer with a No. 3 spindle
at 10 rpm. Preferably, the final product slurry has a viscosity
of from about 200 cP (0.2 Pa/sec) to about 10500 cP (10.5 Pa/sec),
and more preferably from about 350 cP (0.375 Pa/sec) to about 10000
cP (10 Pa/sec), as measured using a Brookfield LV-DVE viscometer
with a No. 3 spindle at 10 rpm.
[0079] In another embodiment, the final product slurry has a solids
content of from about 10 wt % to about 75 wt %, based on total weight
of the slurry. Preferably the final product slurry has a solids
content of from about 15 wt % to about 70 wt %, more preferably
from about 20 wt % to about 65 wt %, based on the total weight of
the slurry. The solids content can be measured using any conventional
means. However, a CEM MAS 700 microwave muffle furnace is particularly
preferred to give results consistent with the values recited herein.
[0080] The final product slurry contains sufficient dried molecular
sieve catalyst to provide a hardened molecular sieve catalyst upon
calcination. In one embodiment, the final product slurry contains
from about 2 wt % to about 98 wt % dried molecular sieve catalyst,
based on total weight of solids in the slurry. In another embodiment,
the final product slurry contains from about 15 wt % to about 80
wt % dried molecular sieve catalyst, based on total weight of solids
in the slurry. Preferably, the final product slurry contains from
about 20 wt % to about 40 wt % dried molecular sieve catalyst, more
preferably about 20 wt % to about 30 wt % dried molecular sieve
catalyst, based on total weight of solids in the slurry.
[0081] The final product slurry also contains sufficient molecular
sieve to be effective in its desired use. In one embodiment, the
final product slurry contains from about 10 wt % to about 93 wt
% molecular sieve, based on total weight of solids in the slurry.
Preferably, the final product slurry contains from about 15 wt %
to about 85 wt % molecular sieve, more preferably from about 20
wt % to about 80 wt % molecular sieve, based on total weight of
solids in the slurry.
[0082] E. Drying and Hardening the Final Product Slurry
[0083] The final product slurry can be dried using any conventional
drying method to form a hardened molecular sieve catalyst composition.
In one embodiment, the final product slurry is spray dried to form
a spray dried product, and the spray dried product is calcined.
Calcination further hardens and/or activates the hardened molecular
sieve catalyst composition. Calcination media useful in this invention
include air, nitrogen, helium, flue gas (combustion product lean
in oxygen), or any combination thereof. Air, optionally containing
water, is a preferred type of calcination medium.
[0084] Conventional calcination temperatures can be used to form
the hardened molecular sieve catalyst of this invention. Such temperatures
are generally in the range from about 400.degree. C. to about 1000.degree.
C., preferably from about 500.degree. C. to about 850.degree. C.,
and most preferably from about 600.degree. C. to about 800.degree.
C.
[0085] Conventional calcination devices can be used in this invention.
Such devices include rotary calciners, fluid bed calciners, batch
ovens, and the like. Calcination time is typically dependent on
the degree of hardening of the molecular sieve catalyst composition
and the temperature.
[0086] In one embodiment of the invention, a spray dried molecular
sieve catalyst composition is heated in nitrogen at a temperature
of from about 700.degree. C. to about 800.degree. C. to form the
hardened molecular sieve catalyst composition. Heating is carried
out for a period of time of from about 30 minutes to about 15 hours,
preferably from about 1 hour to about 10 hours, more preferably
from about 1 hour to about 5 hours, and most preferably from about
2 hours to about 4 hours.
III. Method of Using the Hardened Molecular Sieve Catalyst
[0087] The catalyst compositions described above are useful in
a variety of processes including cracking, of for example a naphtha
feed to light olefin(s) (U.S. Pat. No. 6300537) or higher molecular
weight (MW) hydrocarbons to lower MW hydrocarbons; hydrocracking,
of for example heavy petroleum and/or cyclic feedstock; isomerization,
of for example aromatics such as xylene; polymerization, of for
example one or more olefin(s) to produce a polymer product; reforming;
hydrogenation; dehydrogenation; dewaxing, of for example hydrocarbons
to remove straight chain paraffins; absorption, of for example alkyl
aromatic compounds for separating out isomers thereof; alkylation,
of for example aromatic hydrocarbons such as benzene and alkyl benzene,
optionally with propylene to produce cumene or with long chain olefins;
transalkylation, of for example a combination of aromatic and polyalkylaromatic
hydrocarbons; dealkylation; hydrodecyclization; disproportionation,
of for example toluene to make benzene and paraxylene; oligomerization,
of for example straight and branched chain olefin(s); and dehydrocyclization.
[0088] Preferred processes include processes for converting naphtha
to highly aromatic mixtures; converting light olefin(s) to gasoline,
distillates and lubricants; converting oxygenates to olefin(s);
converting light paraffins to olefins and/or aromatics; and converting
unsaturated hydrocarbons (ethylene and/or acetylene) to aldehydes
for conversion into alcohols, acids and esters.
[0089] The most preferred process of the invention is a process
directed to the conversion of a feedstock to one or more olefin(s).
Typically, the feedstock contains one or more aliphatic-containing
compounds such that the aliphatic moiety contains from 1 to about
50 carbon atoms, such as from 1 to 20 carbon atoms, for example
from 1 to 10 carbon atoms, and particularly from 1 to 4 carbon atoms.
[0090] Non-limiting examples of aliphatic-containing compounds
include alcohols such as methanol and ethanol, alkyl mercaptans
such as methyl mercaptan and ethyl mercaptan, alkyl sulfides such
as methyl sulfide, alkylamines such as methylamine, alkyl ethers
such as dimethyl ether, diethyl ether and methylethyl ether, alkyl
halides such as methyl chloride and ethyl chloride, alkyl ketones
such as dimethyl ketone, formaldehydes, and various acids such as
acetic acid.
[0091] In a preferred embodiment of the process of the invention,
the feedstock contains one or more oxygenates, more specifically,
one or more organic compound(s) containing at least one oxygen atom.
In the most preferred embodiment of the process of invention, the
oxygenate in the feedstock is one or more alcohol(s), preferably
aliphatic alcohol(s) where the aliphatic moiety of the alcohol(s)
has from 1 to 20 carbon atoms, preferably from 1 to 10 carbon atoms,
and most preferably from 1 to 4 carbon atoms. The alcohols useful
as feedstock in the process of the invention include lower straight
and branched chain aliphatic alcohols and their unsaturated counterparts.
[0092] Non-limiting examples of oxygenates include methanol, ethanol,
n-propanol, isopropanol, methyl ethyl ether, dimethyl ether, diethyl
ether, di-isopropyl ether, formaldehyde, dimethyl carbonate, dimethyl
ketone, acetic acid, and mixtures thereof.
[0093] In the most preferred embodiment, the feedstock is selected
from one or more of methanol, ethanol, dimethyl ether, diethyl ether
or a combination thereof, more preferably methanol and dimethyl
ether, and most preferably methanol.
[0094] The various feedstocks discussed above, particularly a feedstock
containing an oxygenate, more particularly a feedstock containing
an alcohol, is converted primarily into one or more olefin(s). The
olefin(s) produced from the feedstock typically have from 2 to 30
carbon atoms, preferably 2 to 8 carbon atoms, more preferably 2
to 6 carbon atoms, still more preferably 2 to 4 carbons atoms, and
most preferably are ethylene and/or propylene.
[0095] The catalyst composition of the invention is particularly
useful in the process that is generally referred to as the gas-to-olefins
(GTO) process or alternatively, the methanol-to-olefins (MTO) process.
In this process, an oxygenated feedstock, most preferably a methanol-containing
feedstock, is converted in the presence of a molecular sieve catalyst
composition into one or more olefin(s), preferably and predominantly,
ethylene and/or propylene.
[0096] Using the catalyst composition of the invention for the
conversion of a feedstock, preferably a feedstock containing one
or more oxygenates, the amount of olefin(s) produced based on the
total weight of hydrocarbon produced is greater than 50 weight percent,
typically greater than 60 weight percent, such as greater than 70
weight percent, and preferably greater than 75 weight percent. In
one embodiment, the amount of ethylene and/or propylene produced
based on the total weight of hydrocarbon product produced is greater
than 65 weight percent, such as greater than 70 weight percent,
for example greater than 75 weight percent, and preferably greater
than 78 weight percent. Typically, the amount ethylene produced
in weight percent based on the total weight of hydrocarbon product
produced, is greater than 30 weight percent, such as greater than
35 weight percent, for example greater than 40 weight percent. In
addition, the amount of propylene produced in weight percent based
on the total weight of hydrocarbon product produced is greater than
20 weight percent, such as greater than 25 weight percent, for example
greater than 30 weight percent, and preferably greater than 35 weight
percent.
[0097] In addition to the oxygenate component, such as methanol,
the feedstock may contains one or more diluent(s), which are generally
non-reactive to the feedstock or molecular sieve catalyst composition
and are typically used to reduce the concentration of the feedstock.
Non-limiting examples of diluents include helium, argon, nitrogen,
carbon monoxide, carbon dioxide, water, essentially non-reactive
paraffins (especially alkanes such as methane, ethane, and propane),
essentially non-reactive aromatic compounds, and mixtures thereof.
The most preferred diluents are water and nitrogen, with water being
particularly preferred.
[0098] The diluent, for example water, may be used either in a
liquid or a vapor form, or a combination thereof. The diluent may
be either added directly to the feedstock entering a reactor or
added directly to the reactor, or added with the molecular sieve
catalyst composition.
[0099] The present process can be conducted over a wide range of
temperatures, such as in the range of from about 200.degree. C.
to about 1000.degree. C., for example from about 250.degree. C.
to about 800.degree. C., including from about 250.degree. C. to
about 750.degree. C., conveniently from about 300.degree. C. to
about 650.degree. C., typically from about 350.degree. C. to about
600.degree. C. and particularly from about 350.degree. C. to about
550.degree. C.
[0100] Similarly, the present process can be conducted over a wide
range of pressures including autogenous pressure. Typically the
partial pressure of the feedstock exclusive of any diluent therein
employed in the process is in the range of from about 0.1 kPaa to
about 5 MPaa, such as from about 5 kPaa to about 1 MPaa, and conveniently
from about 20 kPaa to about 500 kPaa.
[0101] The weight hourly space velocity (WHSV), defined as the
total weight of feedstock excluding any diluents per hour per weight
of molecular sieve in the catalyst composition, typically ranges
from about 1 hr.sup.-1 to about 5000 hr.sup.-1 such as from about
2 hr.sup.-1 to about 3000 hr.sup.-1 for example from about 5 hr.sup.-1
to about 1500 hr.sup.-1 and conveniently from about 10 hr.sup.-1
to about 1000 hr.sup.-1. In one embodiment, the WHSV is greater
than 20 hr.sup.-1 and, where feedstock contains methanol and/or
dimethyl ether, is in the range of from about 20 hr.sup.-1 to about
300 hr.sup.-1.
[0102] Where the process is conducted in a fluidized bed, the superficial
gas velocity (SGV) of the feedstock including diluent and reaction
products within the reactor system, and particularly within a riser
reactor(s), is at least 0.1 meter per second (m/sec), such as greater
than 0.5 m/sec, such as greater than 1 m/sec, for example greater
than 2 m/sec, conveniently greater than 3 m/sec, and typically greater
than 4 m/sec. See for example U.S. patent application Ser. No. 09/708753
filed Nov. 8 2000 which is herein incorporated by reference.
[0103] The process of the invention is conveniently conducted as
a fixed bed process, or more typically as a fluidized bed process
(including a turbulent bed process), such as a continuous fluidized
bed process, and particularly a continuous high velocity fluidized
bed process.
[0104] The process can take place in a variety of catalytic reactors
such as hybrid reactors that have a dense bed or fixed bed reaction
zones and/or fast fluidized bed reaction zones coupled together,
circulating fluidized bed reactors, riser reactors, and the like.
Suitable conventional reactor types are described in for example
U.S. Pat. No. 4076796 U.S. Pat. No. 6287522 (dual riser), and
Fluidization Engineering, D. Kunii and O. Levenspiel, Robert E.
Krieger Publishing Company, New York, N.Y. 1977 which are all herein
fully incorporated by reference.
[0105] The preferred reactor types are riser reactors generally
described in Riser Reactor, Fluidization and Fluid-Particle Systems,
pages 48 to 59 F. A. Zenz and D. F. Othmo, Reinhold Publishing
Corporation, New York, 1960 and U.S. Pat. No. 6166282 (fast-fluidized
bed reactor), and U.S. patent application Ser. No. 09/564613 filed
May 4 2000 (multiple riser reactor), which are all herein fully
incorporated by reference.
[0106] The hardened molecular sieve catalyst of this invention
is particularly useful in systems in which the catalyst is circulated
throughout a reaction system. Circulation type systems that cause
particular problems with attrition of circulated catalyst are those
that include a reactor for carrying out the reaction, and a regenerator
for intermittently regenerating the catalyst.
[0107] In one practical embodiment, the process is conducted as
a fluidized bed process or high velocity fluidized bed process utilizing
a reactor system, a regeneration system and a recovery system. In
such a process the reactor system conveniently includes a fluid
bed reactor system having a first reaction zone within one or more
riser reactor(s) and a second reaction zone within at least one
disengaging vessel, typically comprising one or more cyclones. In
one embodiment, the one or more riser reactor(s) and disengaging
vessel are contained within a single reactor vessel. Fresh feedstock,
preferably containing one or more oxygenates, optionally with one
or more diluent(s), is fed to the one or more riser reactor(s) into
which a molecular sieve catalyst composition or coked version thereof
is introduced. In one embodiment, prior to being introduced to the
riser reactor(s), the molecular sieve catalyst composition or coked
version thereof is contacted with a liquid, preferably water or
methanol, and/or a gas, for example, an inert gas such as nitrogen.
[0108] In an embodiment, the amount of fresh feedstock fed as a
liquid and/or a vapor to the reactor system is in the range of from
0.1 weight percent to about 85 weight percent, such as from about
1 weight percent to about 75 weight percent, more typically from
about 5 weight percent to about 65 weight percent based on the total
weight of the feedstock including any diluent contained therein.
The liquid and vapor feedstocks may be the same composition, or
may contain varying proportions of the same or different feedstocks
with the same or different diluents.
[0109] The feedstock entering the reactor system is preferably
converted, partially or fully, in the first reactor zone into a
gaseous effluent that enters the disengaging vessel along with the
coked catalyst composition. In the preferred embodiment, cyclone(s)
are provided within the disengaging vessel to separate the coked
catalyst composition from the gaseous effluent containing one or
more olefin(s) within the disengaging vessel. Although cyclones
are preferred, gravity effects within the disengaging vessel can
also be used to separate the catalyst composition from the gaseous
effluent. Other methods for separating the catalyst composition
from the gaseous effluent include the use of plates, caps, elbows,
and the like.
[0110] In one embodiment, the disengaging vessel includes a stripping
zone, typically in a lower portion of the disengaging vessel. In
the stripping zone the coked catalyst composition is contacted with
a gas, preferably one or a combination of steam, methane, carbon
dioxide, carbon monoxide, hydrogen, or an inert gas such as argon,
preferably steam, to recover adsorbed hydrocarbons from the coked
catalyst composition that is then introduced to the regeneration
system.
[0111] The coked catalyst composition is withdrawn from the disengaging
vessel and introduced to the regeneration system. The regeneration
system comprises a regenerator where the coked catalyst composition
is contacted with a regeneration medium, preferably a gas containing
oxygen, under conventional regeneration conditions of temperature,
pressure and residence time.
[0112] Non-limiting examples of suitable regeneration media include
one or more of oxygen, O.sub.3 SO.sub.3 N.sub.2O, NO, NO.sub.2
N.sub.2O.sub.5 air, air diluted with nitrogen or carbon dioxide,
oxygen and water (U.S. Pat. No. 6245703), carbon monoxide and/or
hydrogen. Suitable regeneration conditions are those capable of
burning coke from the coked catalyst composition, preferably to
a level less than 0.5 weight percent based on the total weight of
the coked molecular sieve catalyst composition entering the regeneration
system. For example, the regeneration temperature may be in the
range of from about 200.degree. C. to about 1500.degree. C., such
as from about 300.degree. C. to about 1000.degree. C., for example
from about 450.degree. C. to about 750.degree. C., and conveniently
from about 550.degree. C. to 700.degree. C. The regeneration pressure
may be in the range of from about 15 psia (103 kpaa) to about 500
psia (3448 kpaa), such as from about 20 psia (138 kPaa) to about
250 psia (1724 kPaa), including from about 25 psia (172 kPaa) to
about 150 psia (1034 kpaa), and conveniently from about 30 psia
(207 kpaa) to about 60 psia (414 kpaa).
[0113] The residence time of the catalyst composition in the regenerator
may be in the range of from about one minute to several hours, such
as from about one minute to 100 minutes, and the volume of oxygen
in the regeneration gas may be in the range of from about 0.01 mole
percent to about 5 mole percent based on the total volume of the
gas.
[0114] The burning of coke in the regeneration step is an exothermic
reaction, and in an embodiment, the temperature within the regeneration
system is controlled by various techniques in the art including
feeding a cooled gas to the regenerator vessel, operated either
in a batch, continuous, or semi-continuous mode, or a combination
thereof. A preferred technique involves withdrawing the regenerated
catalyst composition from the regeneration system and passing it
through a catalyst cooler to form a cooled regenerated catalyst
composition. The catalyst cooler, in an embodiment, is a heat exchanger
that is located either internal or external to the regeneration
system. Other methods for operating a regeneration system are in
disclosed U.S. Pat. No. 6290916 (controlling moisture), which
is herein fully incorporated by reference.
[0115] The regenerated catalyst composition withdrawn from the
regeneration system, preferably from the catalyst cooler, is combined
with a fresh molecular sieve catalyst composition and/or re-circulated
molecular sieve catalyst composition and/or feedstock and/or fresh
gas or liquids, and returned to the riser reactor(s). In one embodiment,
the regenerated catalyst composition withdrawn from the regeneration
system is returned to the riser reactor(s) directly, preferably
after passing through a catalyst cooler. A carrier, such as an inert
gas, feedstock vapor, steam or the like, may be used, semi-continuously
or continuously, to facilitate the introduction of the regenerated
catalyst composition to the reactor system, preferably to the one
or more riser reactor(s).
[0116] By controlling the flow of the regenerated catalyst composition
or cooled regenerated catalyst composition from the regeneration
system to the reactor system, the optimum level of coke on the molecular
sieve catalyst composition entering the reactor is maintained. There
are many techniques for controlling the flow of a catalyst composition
described in Michael Louge, Experimental Techniques, Circulating
Fluidized Beds, Grace, Avidan and Knowlton, eds., Blackie, 1997
(336-337), which is herein incorporated by reference.
[0117] Coke levels on the catalyst composition are measured by
withdrawing the catalyst composition from the conversion process
and determining its carbon content. Typical levels of coke on the
molecular sieve catalyst composition, after regeneration, are in
the range of from 0.01 weight percent to about 15 weight percent,
such as from about 0.1 weight percent to about 10 weight percent,
for example from about 0.2 weight percent to about 5 weight percent,
and conveniently from about 0.3 weight percent to about 2 weight
percent based on the weight of the molecular sieve.
[0118] The gaseous effluent is withdrawn from the disengaging system
and is passed through a recovery system. There are many well known
recovery systems, techniques and sequences that are useful in separating
olefin(s) and purifying olefin(s) from the gaseous effluent. Recovery
systems generally comprise one or more or a combination of various
separation, fractionation and/or distillation towers, columns, splitters,
or trains, reaction systems such as ethylbenzene manufacture (U.S.
Pat. No. 5476978) and other derivative processes such as aldehydes,
ketones and ester manufacture (U.S. Pat. No. 5675041), and other
associated equipment, for example various condensers, heat exchangers,
refrigeration systems or chill trains, compressors, knock-out drums
or pots, pumps, and the like.
[0119] Non-limiting examples of these towers, columns, splitters
or trains used alone or in combination include one or more of a
demethanizer, preferably a high temperature demethanizer, a dethanizer,
a depropanizer, a wash tower often referred to as a caustic wash
tower and/or quench tower, absorbers, adsorbers, membranes, ethylene
(C2) splitter, propylene (C3) splitter and butene (C4) splitter.
[0120] Various recovery systems useful for recovering olefin(s),
such as ethylene, propylene and/or butene, are described in U.S.
Pat. No. 5960643 (secondary rich ethylene stream), U.S. Pat. Nos.
5019143 5452581 and 5082481 (membrane separations), U.S.
Pat. No. 5672197 (pressure dependent adsorbents), U.S. Pat. No.
6069288 (hydrogen removal), U.S. Pat. No. 5904880 (recovered
methanol to hydrogen and carbon dioxide in one step), U.S. Pat.
No. 5927063 (recovered methanol to gas turbine power plant), and
U.S. Pat. No. 6121504 (direct product quench), U.S. Pat. No. 6121503
(high purity olefins without superfractionation), and U.S. Pat.
No. 6293998 (pressure swing adsorption), which are all herein
fully incorporated by reference.
[0121] Other recovery systems that include purification systems,
for example for the purification of olefin(s), are described in
Kirk-Othmer Encyclopedia of Chemical Technology, 4th Edition, Volume
9 John Wiley & Sons, 1996 pages 249-271 and 894-899 which
is herein incorporated by reference. Purification systems are also
described in for example, U.S. Pat. No. 6271428 (purification
of a diolefin hydrocarbon stream), U.S. Pat. No. 6293999 (separating
propylene from propane), and U.S. patent application Ser. No. 09/689363
filed Oct. 20 2000 (purge stream using hydrating catalyst), which
are herein incorporated by reference.
[0122] Generally accompanying most recovery systems is the production,
generation or accumulation of additional products, by-products and/or
contaminants along with the preferred prime products. The preferred
prime products, the light olefins, such as ethylene and propylene,
are typically purified for use in derivative manufacturing processes
such as polymerization processes. Therefore, in the most preferred
embodiment of the recovery system, the recovery system also includes
a purification system. For example, the light olefin(s) produced
particularly in a MTO process are passed through a purification
system that removes low levels of by-products or contaminants.
[0123] Non-limiting examples of contaminants and by-products include
generally polar compounds such as water, alcohols, carboxylic acids,
ethers, carbon oxides, sulfur compounds such as hydrogen sulfide,
carbonyl sulfides and mercaptans, ammonia and other nitrogen compounds,
arsine, phosphine and chlorides. Other contaminants or by-products
include hydrogen and hydrocarbons such as acetylene, methyl acetylene,
propadiene, butadiene and butyne.
[0124] Typically, in converting one or more oxygenates to olefin(s)
having 2 or 3 carbon atoms, a minor amount hydrocarbons, particularly
olefin(s), having 4 or more carbon atoms is also produced. The amount
of C.sub.4+ hydrocarbons is normally less than 20 weight percent,
such as less than 10 weight percent, for example less than 5 weight
percent, and particularly less than 2 weight percent, based on the
total weight of the effluent gas withdrawn from the process, excluding
water. Typically, therefore the recovery system may include one
or more reaction systems for converting the C.sub.4+ impurities
to useful products.
[0125] Non-limiting examples of such reaction systems are described
in U.S. Pat. No. 5955640 (converting a four carbon product into
butene-1), U.S. Pat. No. 4774375 (isobutane and butene-2 oligomerized
to an alkylate gasoline), U.S. Pat. No. 6049017 (dimerization
of n-butylene), U.S. Pat. Nos. 4287369 and 5763678 (carbonylation
or hydroformulation of higher olefins with carbon dioxide and hydrogen
making carbonyl compounds), U.S. Pat. No. 4542252 (multistage
adiabatic process), U.S. Pat. No. 5634354 (olefin-hydrogen recovery),
and Cosyns, J. et al., Process for Upgrading C3 C4 and C5 Olefinic
Streams, Pet. & Coal, Vol. 37 No. 4 (1995) (dimerizing or oligomerizing
propylene, butylene and pentylene), which are all fully herein incorporated
by reference.
[0126] The preferred light olefin(s) produced by any one of the
processes described above are high purity prime olefin(s) products
that contain a single carbon number olefin in an amount greater
than 80 percent, such as greater than 90 weight percent, such as
greater than 95 weight percent, for example at least about 99 weight
percent, based on the total weight of the olefin.
[0127] In one practical embodiment, the process of the invention
forms part of an integrated process for producing light olefin(s)
from a hydrocarbon feedstock, preferably a gaseous hydrocarbon feedstock,
particularly methane and/or ethane. The first step in the process
is passing the gaseous feedstock, preferably in combination with
a water stream, to a syngas production zone to produce a synthesis
gas (syngas) stream, typically comprising carbon dioxide, carbon
monoxide and hydrogen. Syngas production is well known, and typical
syngas temperatures are in the range of from about 700.degree. C.
to about 1200.degree. C. and syngas pressures are in the range of
from about 2 MPa to about 100 MPa. Synthesis gas streams are produced
from natural gas, petroleum liquids, and carbonaceous materials
such as coal, recycled plastic, municipal waste or any other organic
material. Preferably synthesis gas stream is produced via steam
reforming of natural gas.
[0128] The next step in the process involves contacting the synthesis
gas stream generally with a heterogeneous catalyst, typically a
copper based catalyst, to produce an oxygenate containing stream,
often in combination with water. In one embodiment, the contacting
step is conducted at temperature in the range of from about 150.degree.
C. to about 450.degree. C. and a pressure in the range of from about
5 MPa to about 10 MPa.
[0129] This oxygenate containing stream, or crude methanol, typically
contains the alcohol product and various other components such as
ethers, particularly dimethyl ether, ketones, aldehydes, dissolved
gases such as hydrogen methane, carbon oxide and nitrogen, and fuel
oil. The oxygenate containing stream, crude methanol, in the preferred
embodiment is passed through a well known purification processes,
distillation, separation and fractionation, resulting in a purified
oxygenate containing stream, for example, commercial Grade A and
AA methanol.
[0130] The oxygenate containing stream or purified oxygenate containing
stream, optionally with one or more diluents, can then be used as
a feedstock in a process to produce light olefin(s), such as ethylene
and/or propylene. Non-limiting examples of this integrated process
are described in EP-B-0 933 345 which is herein fully incorporated
by reference.
[0131] In another more fully integrated process, that optionally
is combined with the integrated processes described above, the olefin(s)
produced are directed to, in one embodiment, one or more polymerization
processes for producing various polyolefins. (See for example U.S.
patent application Ser. No. 09/615376 filed Jul. 13 2000 which
is herein fully incorporated by reference.)
[0132] Polymerization processes include solution, gas phase, slurry
phase and a high pressure processes, or a combination thereof. Particularly
preferred is a gas phase or a slurry phase polymerization of one
or more olefin(s) at least one of which is ethylene or propylene.
These polymerization processes utilize a polymerization catalyst
that can include any one or a combination of the molecular sieve
catalysts discussed above. However, the preferred polymerization
catalysts are the Ziegler-Natta, Phillips-type, metallocene, metallocene-type
and advanced polymerization catalysts, and mixtures thereof.
[0133] In a preferred embodiment, the integrated process comprises
a process for polymerizing one or more olefin(s) in the presence
of a polymerization catalyst system in a polymerization reactor
to produce one or more polymer products, wherein the one or more
olefin(s) have been made by converting an alcohol, particularly
methanol, using a molecular sieve catalyst composition as described
above. The preferred polymerization process is a gas phase polymerization
process and at least one of the olefins(s) is either ethylene or
propylene, and preferably the polymerization catalyst system is
a supported metallocene catalyst system. In this embodiment, the
supported metallocene catalyst system comprises a support, a metallocene
or metallocene-type compound and an activator, preferably the activator
is a non-coordinating anion or alumoxane, or combination thereof,
and most preferably the activator is alumoxane.
[0134] The polymers produced by the polymerization processes described
above include linear low density polyethylene, elastomers, plastomers,
high density polyethylene, low density polyethylene, polypropylene
and polypropylene copolymers. The propylene based polymers produced
by the polymerization processes include atactic polypropylene, isotactic
polypropylene, syndiotactic polypropylene, and propylene random,
block or impact copolymers.
IV. Examples of the Hardened Molecular Sieve Catalyst
[0135] Various embodiments of this invention are described in greater
detail with reference to the following examples, which are intended
to illustrate specific embodiments within the overall scope of the
invention as claimed.
EXAMPLE-1
[0136] A slurry containing 45 wt % solid was prepared by mixing
1125 g of a spray dried catalyst (which contained 40% SAPO-34
10.6% alumina, and 49.4% clay) with 875 g of deionized water using
a Yamato 4000D mixer (Yamato Scientific America Inc., Orangeburg,
N.Y.) for 10 minutes at 600 RPM. The slurry was then mixed using
a high-shear mixer, Yamato L4RT-A (Yamato Scientific America Inc.,
Orangeburg, N.Y.), at 6000 RPM for 5 minutes. The resultant final
product slurry had a pH of 3.9 and density of 1.45 g/cc, measured
at 25.degree. C. The viscosity of the slurry was 2180 centipoise
at 24.degree. C., which was measured with a Brookfield LV viscometer,
using a #3 spindle at 10 RPM.
EXAMPLE-2 (COMPARATIVE)
[0137] 700 g of the final product slurry produced in EXAMPLE-1
was spray dried using a Yamato DL-41 spray dryer, operating in a
down spray mode, using a 1 mm atomization nozzle. Spray drying conditions
were as follows: feed rate, 40 g/min; inlet temperature, 350.degree.
C.; atomization pressure, 1 bar; and carrier gas flow at 60% of
full setting. Spray dried products were collected in a cyclone,
and calcined in a muffle furnace at 650.degree. C. in air for 2
hours. The calcined samples were tested for attrition resistance,
and found to have an ARI of 0.59 wt %/hr. The result is shown in
the Figure.
EXAMPLE-3
[0138] 843.75 g of the spray dried catalyst used in EXAMPLE 1 were
added to 656.25 g deionized water, and mixed at 600 RPM using a
Yamato 4000D mixer (Yamato Scientific America Inc., Orangeburg,
N.Y.) for 10 minutes to produce a slurry. The slurry was then mixed
using a high-shear mixer, Yamato L4RT-A (Yamato Scientific America
Inc., Orangeburg, N.Y.) at 6000 RPM for 10 minutes. To this slurry,
168.5 g of SAPO-34 molecular sieve was added, then further mixing
was carried out using the same procedure as outlined in EXAMPLE-1.
A composition made of 81.06 g of Reheis MicroDry aluminum chlorohydrate
(Reheis Chemical Inc., Berkeley Heights, N.J.) and 118.84 g of deionized
water was then added, and further mixing carried out using the same
protocol outlined in EXAMPLE-1. Finally, 131.57 g of kaolin clay
(Engelhard USP kaolin clay, Engelhard Corporation, Iselin, N.J.)
was added and further mixing carried out using the same routine
as in EXAMPLE-1. This resulted in a final product slurry containing
45 wt % solids, of which 75% was spray dried product and 25% was
virgin SAPO-34 molecular sieve, aluminum chlorohydrate, and clay.
The final product slurry had a pH value of 4.0 measured at 25.degree.
C., and a density of 1.39 g/cc, measured at 25.degree. C. The viscosity
of the final product slurry was 3400 centipoise at 24.degree. C.,
which was measured with a Brookfield LV viscometer, using a #3 spindle
at 10 RPM.
EXAMPLE-4
[0139] 700 g of the final product slurry produced in EXAMPLE-3
was spray dried using a Yamato DL-41 spray dryer, operating in a
down spray mode, using a 1 mm atomization nozzle. Spray drying conditions
were as follows: feed rate, 40 g/min; inlet temperature, 350.degree.
C.; atomization pressure, 1 bar; and carrier gas flow at 60% of
full setting. Spray dried products were collected in a cyclone,
and then calcined in a muffle furnace at 650.degree. C. in air for
2 hours. The calcined samples were tested for attrition resistance,
and found to have an ARI of 0.36 wt %/hr. The result is shown in
the Figure.
EXAMPLE-5
[0140] 562.5 g of the spray dried catalyst used in EXAMPLE 1 was
added to 437.5 g deionized water, and mixed at 600 RPM using a Yamato
4000D mixer (Yamato Scientific America Inc., Orangeburg, N.Y.) for
10 minutes to form a slurry. The slurry was then mixed using a high-shear
mixer, Yamato L4RT-A (Yamato Scientific America Inc., Orangeburg,
N.Y.) at 6000 RPM for 10 minutes. To this slurry, 337.0 g of SAPO-34
molecular sieve was added, and further mixing was carried out using
the same procedure as outlined in EXAMPLE-1. To that slurry was
added a composition made of 162.18 g of Reheis MicroDry aluminum
chlorohydrate (Reheis Chemical Inc., Berkeley Heights, N.J.) and
237.68 of deionized water. Further mixing was carried out using
the same protocol outlined in EXAMPLE-1. Finally, 263.14 g of kaolin
clay (Engelhard USP kaolin clay, Engelhard Corporation, Iselin,
N.J.) was added and mixed using the same routine used in EXAMPLE-1.
This resulted in a final product slurry containing 45 wt % solids,
of which 50% came from the spray dried molecular sieve and 50% came
from the combination of virgin SAPO-34 molecular sieve, aluminum
chlorohydrate, and clay. The final product slurry had a pH value
of 4.0 measured at 25.degree. C., and a density of 1.38 g/cc, measured
at 25.degree. C. The viscosity of the final product slurry was 4860
centipoise at 24.degree. C., which was measured with a Brookfield
LV viscometer, using a #3 spindle at 10 RPM.
EXAMPLE-6
[0141] 700 g of the final product slurry produced in EXAMPLE-5
was spray dried using a Yamato DL-41 spray dryer, operating in a
down spray mode, using a 1 mm atomization nozzle. Spray drying conditions
were as follows: feed rate, 40 g/min; inlet temperature, 350.degree.
C.; atomization pressure, 1 bar; carrier gas flow at 60% of full
setting. Spray dried products were collected in a cyclone, and calcined
in a muffle furnace at 650.degree. C. in air for 2 hours. The calcined
samples were tested for attrition resistance, and found to have
an ARI of 0.40 wt %/hr. The result is shown in the Figure.
EXAMPLE-7
[0142] 281.25 g of the spray dried catalyst used in EXAMPLE 1 was
added to 218.75 g deionized water, and mixed at 600 RPM using a
Yamato 4000D mixer (Yamato Scientific America Inc., Orangeburg,
N.Y.) for 10 minutes to form a slurry. The slurry was then mixed
using a high-shear mixer, Yamato L4RT-A (Yamato Scientific America
Inc., Orangeburg, N.Y.) at 6000 RPM for 10 minutes. To this slurry,
505.0 g of SAPO-34 molecular sieve was added, and further mixing
was carried out using the same procedure as outlined in EXAMPLE-1.
To that slurry was added a composition made of 243.27 g of Reheis
MicroDry aluminum chlorohydrate (Reheis Chemical Inc., Berkeley
Heights, N.J.) and 356.52 g of deionized water. Further mixing was
carried out using the same protocol outlined in EXAMPLE-1. Finally,
394.71 g of kaolin clay (Engelhard USP kaolin clay, Engelhard Corporation,
Iselin, N.J.) was added and mixed using the same routine used in
EXAMPLE-1. This resulted in a final product slurry containing 45
wt % solids, of which 25% came from the spray dried molecular sieve
and 75% came from the combination of the virgin SAPO-34 molecular
sieve, aluminum chlorohydrate, and clay. The final product slurry
had a pH value of 4.0 measured at 25.degree. C., and a density
of 1.46 g/cc, measured at 25.degree. C. The viscosity of the final
product slurry was 7610 centipoise at 24.degree. C., which was
measured with a Brookfield LV viscometer, using a #3 spindle at
10 RPM.
EXAMPLE-8
[0143] 700 g of the final product slurry produced in EXAMPLE-7
was spray dried using a Yamato DL-41 spray dryer, operating in a
down spray mode, using a 1 mm atomization nozzle. Spray drying conditions
were: feed rate, 40 g/min; inlet temperature, 350.degree. C.; atomization
pressure, 1 bar; and carrier gas flow at 60% of full setting. Spray
dried products were collected in a cyclone, and calcined in a muffle
furnace at 650.degree. C. in air for 2 hours. The calcined samples
were tested for attrition resistance, and found to have an ARI of
0.25 wt %/hr. The result is shown in the Figure.
EXAMPLE-9 (COMPARATIVE)
[0144] This example is similar to that of EXAMPLES 3 5 and 7
except that no spray dried product was contained in the final product
slurry. A slurry containing 45 wt % solid (on calcined basis), 40%
being SAPO-34 10.6% Al.sub.2O.sub.3 and 49.4% clay, was prepared
by adding 2988.93 g of a SAPO-34 filtercake to 1703.84 g of deionized
water, and mixing at 1500 RPM using a Yamato 4000D mixer (Yamato
Scientific America Inc., Orangeburg, N.Y.) for 15 minutes. The slurry
further mixed by a high-shear treatment using a Silverson high shear
L4RT-A mixer at 6000 RPM for 10 minutes (Slurry A). Slurry A had
a pH value of 6.3 measured at 26.degree. C. An aluminum chlorohydrate
slurry was made by adding 869.03 g of Reheis MicroDry aluminum chlorohyrate
(Reheis Inc., Berkeley Heights, N.J.) to 859.12 g of deionized water
and mixing at 1500 RPM using a Yamato 4000D mixer (Yamato Scientific
America Inc., Orangeburg, N.Y.) for 15 minutes. This slurry was
further mixed by a high-shear treatment using a Silverson high shear
L4RT-A mixer at 6000 RPM for 10 minutes to form a Slurry B, having
a pH of 3.3 measured at 31.degree. C. Slurry A, containing the
SAPO-34 molecular sieve, and the Slurry B, containing the aluminum
chlorohydrate, were combined and mixed at 1500 RPM using a Yamato
4000D mixer (Yamato Scientific America Inc., Orangeburg, N.Y.) for
15 minutes. This slurry was then further mixed using a Silverson
high-shear mixer at 6000 RPM for 10 minutes, and had a pH value
of 4.2 measured at 30.degree. C. To this slurry was added 2302.3
g of kaolin clay (Engelhard ASP Ultrafine kaolin clay, Engelhard
Corporation, Iselin, N.J.), and the slurry was constantly mixed
at 250-400 RPM, then further mixed at 1500 RPM using a Yamato 4000D
mixer (Yamato Scientific America Inc., Orangeburg, N.Y.) for 15
minutes. This slurry was further mixed by a high-shear mixing step
using a Silverson L4RT-A mixer at 6000 RPM for 10 minutes. The
solid content of this slurry was adjusted to 45% solids by adding
283.97 g of deionized water, then further mixed at 1500 RPM for
15 minutes using the Yamato mixer. Subsequent high-shear mixing
was then carried out using the Silverson mixer at 6000 RPM for
10 minutes to form a final product slurry. This final product slurry
had a pH value of 3.8 measured at 36.degree. C. A final product
slurry of 8000 g was formed, which contained 45% solids (on calcined
basis). The solids were comprised of 40% SAPO-34 molecular seive,
10.6% alumina, and 49.4% clay. The final product slurry had a pH
value of 4.34 measured at 25.degree. C.; a density of 1.40 g/cc,
measured at 23.degree. C.; and a viscosity of 4920 centipoise at
24.degree. C., which was measured with a Brookfield LV viscometer,
using a #3 spindle at 10 RPM.
EXAMPLE-10 (COMPARATIVE)
[0145] 750 g of the final product slurry produced in EXAMPLE-9
was spray dried using a Yamato DL-41 spray dryer, operating in a
down spray mode, using a 1 mm atomization nozzle. Spray drying conditions
were: feed rate, 40 g/min; inlet temperature, 350.degree. C.; atomization
pressure, 1 bar; and carrier gas flow at 60% of full setting. Spray
dried products were collected in a cyclone, and calcined in a muffle
furnace at 650.degree. C. in air for 2 hours. The calcined samples
were tested for attrition resistance, and found to have an ARI of
0.95 wt %/hr. The result is shown in the Figure.
[0146] Having now fully described this invention, it will be appreciated
by those skilled in the art that the invention can be performed
within a wide range of parameters within what is claimed, without
departing from the spirit and scope of the invention. |