Title of Invention

"METHOD OF STARTING UP A REACTION SYSTEM"

Abstract The invention is directed to methods of starting up reaction systems. The reaction systems are those that use catalysts that comprise molecular sieves, particularly metalloaluminophosphate molecular sieves, especially metalloaluminophosphate molecular sieves which are susceptible to loss of catalytic activity due to contact with water molecules. The methods provide appropriate mechanisms of heating and loading the activated molecular sieves to protect against loss of catalytic activity that can occur due to contact with water molecules.
Full Text FIELD OF THE INVENTION
[0001] This invention relates to processes or methods of starting up
reaction systems. In particular, this invention relates to processes or methods of starting up reaction systems, while maintaining or protecting the catalytic activity of molecular sieves that are susceptible to loss of catalytic activity due to contact with water molecules. BACKGROUND OF THE INVENTION
[0002] Molecular sieves are generally derived from alumina silicate
materials and contain a pore system, which is a network of uniform pores and
empty cavities. These pores and cavities catch molecules that have a size equal to
or less than the size of the pores and cavities, and repel molecules of a larger size.
[0003] The pores and cavities of molecular sieves are formed as a result of
adding template materials during the molecular sieve manufacturing process. During the formation of the molecular sieves themselves, a lattice type chemical structure is formed from the alumina silicate type materials. This lattice type structure essentially wraps around the template material, with the template material acting as a means of forming the pore structure within the molecular sieve. The resulting molecular sieve may be combined with other components for the benefit of adjusting various properties of the molecular sieve or to form larger particles.
[0004] To make the molecular sieve suitable for use, the template must be
removed so that the pores and cavities are open to catch molecules, either for the
purpose of adsorbing the molecules from the environment or to react the
molecules to form a desired product. The reaction occurs when the molecules
come into contact with catalytic sites located within the pore system, particularly
within one or more of the empty cavities or cages as sometimes called.
[0005] The template is conventionally removed from the molecular sieve
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, the molecular sieve is considered to be activated or ready for use. The


activated molecular sieve has its pore system, including the empty cavities or
cages open to the immediate environment, and ready for use.
[0006] Activated metalloaluminophosphate molecular sieves that have
catalytic sites within their microporous structure, e.g., silicoaluminophosphate
(SAPO) molecular sieves, have been found to be sensitive to moisture. In general,
significant exposure of the activated molecular sieves to moisture has been found
to deactivate the catalytic activity of the molecular sieves. Unfortunately, methods
of protecting activated metalloaluminophosphate molecular sieves against the
harmful effects of moisture are limited.
[0007] US 6,316,683 Bl (Janssen et al.) discloses a method of protecting
catalytic activity of a SAPO molecular sieve by shielding the internal active sites
of the molecular sieve from contact with moisture. The template itself can serve
as the shield, or an anhydrous blanket can serve as a shield for an activated sieve
that does not include template. It is desirable to shield the active sites, because
activated SAPO molecular sieves will exhibit a loss of catalytic activity when
exposed to moisture.
[0008] US 4,764,269 (Edwards et al.) discloses a method of protecting
SAPO-37 catalyst from deactivating as a result of contact with moisture. The
catalyst is maintained under storage conditions such that the organic template
component of the molecular sieve is retained in the SAPO-37 molecular sieve,
until such time as the catalyst is placed into a catalytic cracking unit. When the
catalyst is exposed to the FCC reaction conditions, wherein the reactor is operated
at 400° to 600°C and the regenerator operated at about 600° to 850°C, the organic
template is removed from the molecular sieve pore structure, and the catalyst
becomes activated for the cracking of hydrocarbons. According to this procedure,
there is little if any contact with moisture.
[0009] Mees et al., "Improvement of the Hydrothermal Stability of SAPO-
34," Chem. Commun., 2003, (1), 44-45, first published as an advance article on
the web Nov. 22, 2002, discloses a method of protecting SAPO-34 molecular
sieve, based on a reversible reaction of NH3 with acid sites of the sieve. The
method transforms a H+-SAPO-34 into an NH4
+-SAPO-34 in reversible way. The
NH4
+-SAPO-34 is said to be able to withstand severe steaming for an extended
period of time without loss of structural integrity and acidity.
[0010] As new large scale, commercial production facilities, which use
molecular sieves in the production process, continue to be implemented,
protecting the activated molecular sieves from loss of catalytic activity as a result
of contact with moisture continues to become an even greater challenge. It is a
particular challenge in catalytic reaction systems where large scale operation will
entail contacting the activated molecular sieve with water vapor, particularly at
times of unit start up. During such times, it may be necessary to use steam to heat
the reaction system. However, contact of the activated sieve with water vapor can
result in sieve that has little to no catalytic activity, which means that the sieve
would then be of essentially no commercial value. It is, therefore, important that
methods of starting up reaction systems that incorporate the use of molecular
sieves susceptible to loss of catalytic activity due to contact with water molecules
be developed.
SUMMARY OF THE INVENTION
[0011] In one aspect, this invention provides methods that assist in the
protection of molecular sieves against loss of catalytic activity in starting up a
reaction system. These methods are particularly effective under certain conditions
where activated molecular sieve is contacted with water vapor or steam during
reaction system start up.
[0012] In one aspect of the invention, there is provided a process of
starting up a reaction system. The process comprises heating at least a portion of
the reaction system. After the portion of the system is heated, a catalyst
comprising activated metalloaluminophosphate molecular sieve is loaded into the
heated portion. The loaded catalyst is further heated, and the further heated
catalyst is contacted with feed. In one embodiment, the reaction system is a dense
bed reaction system, fixed bed reaction system, fluidized bed reaction system, fast
fluidized bed reaction system, circulating fluidized bed reaction system, or riser
reactor system.
10013] In one embodiment the reaction system comprises a reactor and
regenerator. Preferably, the catalyst is loaded into the regenerator, further heated
in the regenerator, and circulated to the reactor prior to contacting with feed. The
reactor is suitably a hot wall or cold wall reactor.
[0014] The invention further provides a process of starting up a reactor
system having a reactor and regenerator. The reactor and regenerator are heated,
and catalyst comprising activated metalloaluminophosphate molecular sieve is
loaded into the heated reactor or regenerator. The catalyst loaded into the reactor
or regenerator is further heated, and then contacted with feed.
[0015] Still further provided by the invention is a process of starting up a
fluidized bed reactor system having a reactor in connection with a regenerator.
The reactor and regenerator are heated and catalyst comprising activated
metalloaluminophosphate molecular sieve is loaded into the heated regenerator.
The catalyst loaded into the regenerator is further heated. Heated catalyst is then
circulated between the regenerator and reactor, with the heated catalyst contacting
feed in the heated reactor.
[0016] In one embodiment of the invention, the heated portion of the
reaction system into which the activated metalloaluminophosphate molecular
sieve is loaded is heated to a temperature of at least 150°C prior to catalyst
loading. Preferably, the heated portion of the reaction system into which the
activated metalloaluminophosphate molecular sieve is loaded is heated to a
temperature of at least 200°C prior to catalyst loading, more preferably at least
300°C. Most preferably, the heated portion of the reaction system into which the
activated metalloaluminophosphate molecular sieve is loaded is heated to a
temperature of at least water critical temperature prior to catalyst loading.
[0017] In another embodiment of the invention, the catalyst loaded into
the reaction system is maintained at a predetermined catalytic activity index while
the sieve is in the reaction system. Desirably, the predetermined catalytic activity
index is at least 0.7, preferably at least 0.8, and more prefeably, at least 0.9.
[0018] In yet another embodiment, the metalloaluminophosphate
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, A1PO-5, A1PO-11, A1PO-18, A1PO-31, A1PO-34, A1PO-36,
A1PO-37, A1PO-46, metal containing molecular sieves thereof, and mixtures
thereof.
[0019] According to the invention, the feed to the system is selected from
the group consisting of kerosenes, naphthas, diesels, light or heavy gas oils,
vacuum distillates or residua, light cycle oils, heavy cycle oils, benzenes, xylenes,
toluenes, naphthalenes, and alcohols.
[0020] In another embodiment, the catalyst loaded into the reaction system
is heated to a temperature that is at least 100°C higher than when first loaded into
the reaction system. Preferably, the catalyst loaded into the reaction system is
heated to a temperature of at least 400°C. In one aspect, the catalyst loaded into
the reaction system can be heated by combusting hydrocarbon oil in the reaction
system,
[0021] The reaction system of the invention is widely applicable to many
types of processes. Examples of reaction systems are selected from the group
consisting of catalytic cracking reaction systems, transalkylation reaction systems,
isomerization reaction systems, catalytic dewaxing systems, alkylation reaction
systems, hydrocracking reaction systems, systems for converting paraffins to
olefms, systems for converting paraffins to aromatics, systems for converting
olefms to gasoline, systems for converting olefms to distillate, systems for
converting olefms to lubes, systems for converting alcohols to olefms,
disproportionation reaction systems, systems for converting aromatics to higher
aromatics, systems for adsorbing aromatics, systems for converting oxygenates to
olefms, systems for converting oxygenates to aromatics, systems for
oligomermng olefms, and systems for converting unsaturated hydrocarbons to
aldehydes.
[0022] In one embodiment of the invention, the activated
metalloaluminophosphate molecular sieve is a silicoaluminophosphate having a
Si/Al ratio of not greater than 0.5. In a preferred embodiment, the activated
metalloaluminophosphate molecular sieve is a silicoaluminophosphate having a
Si/Al ratio of not greater than 0.3, particularly not greater than 0.2, more
preferably not greater than 0.15, and most preferably not greater than 0.1.
Brief Description of the Drawings
|0023] Examples of various embodiments of this invention are shown in
the attached Figures, wherein:
[0024] FIG. 1 is flow diagram of a reaction system comprising a reactor
unit and a regenerator, the regenerator being heated by air, and the reactor being
heated by steam during start up;
[0025] FIG. 2 is flow diagram of a reaction system comprising a reactor
unit and a regenerator, the regenerator and reactor being heated by air or gas rather
than by steam;
[0026] FIG. 3 is flow diagram of a reaction system comprising a reactor
unit and a regenerator, the regenerator and reactor being heated by air or gas from
two different sources; and
[0027] FIG. 4 is flow diagram of a reaction system comprising a reactor
unit and a regenerator, the regenerator being heated by air, and the reactor being
heated by a gas that is heated using equipment in a recovery section of the
reaction system.
DETAILED DESCRIPTION OF THE INVENTION
L Start Up Methods to Protect Against Loss of Catalytic Activity
[0028] This invention is directed to methods of starting up reaction
systems that use catalysts that comprise molecular sieves, particularly
metalloaluminophosphate molecular sieves, which are susceptible to loss of
catalytic activity due to contact with water molecules. Since many
metalloaluminophosphate molecular sieves, particularly silicoaluminophosphate
molecular sieves, are susceptible to loss of catalytic activity upon activation and
contact with water molecules, start up methods are particularly important. If
activated catalyst is left exposed to water vapor for even short periods of time,
significant loss of catalytic activity can occur.
[0029] According to this invention, activated catalyst is loaded into a
reaction system and maintained at conditions so as to minimize or avoid loss of
catalytic activity, until feed is fully introduced into the reaction system. In one
embodiment, the reaction system is sufficiently heated prior to introduction of the
activated catalyst into the system. Alternatively, conditions of temperature of the
catalyst, water partial pressure of the reaction system, and time of contact with
water molecules are controlled so that loss of catalytic activity is not significant.
These conditions are controlled so that the activated catalyst adsorbs little if any
water. The greater the amount of water adsorbed, the greater the rate of
deactivation of the catalyst.
[0030] Once catalyst has been loaded into the reaction system and heated
to a temperature effective to start the reaction process, feed is introduced into the
reaction system and contacted with the catalyst. Once the system is at reaction
conditions, the temperature will be sufficiently high so that deactivation by
contact with water molecules will not be problematic.
[0031] Deactivation of the molecular sieve is determined in this invention
by a catalytic activity index (CAI). The CAI provides a measure of catalyst
deactivation as a result of catalyst exposure temperature, relative water pressure,
and water contact time working in concert to deactivate the catalyst. Thus, for
example, although a low relative water pressure generally causes less catalyst
deactivation, higher relative water pressures may be mitigated by limiting the
contact time or controlling the catalyst exposure temperature. The CAI formula of
this invention fully describes allowable combinations of time, temperature and
relative water pressure to limit catalyst deactivation to specified values.
[0032] The catalytic activity index of this invention is defined as the actual
catalytic activity at time of measurement divided by the maximum catalytic
activity (before any deactivation occurs). In this regard, the CAI would be 0 for a
completely deactivated catalyst, and 1 for a catalyst having maximum catalytic
activity.
[0033] The catalytic activity index (CAI) is calculated according to the
following equation.
CAI = exp(/(T) */PPwater)" * alpha * t)
wherein
t = time of contact of catalyst with water (hours)
T - temperature at contact (°C)
PPwater = Partial Pressure of water in contact gas (psia)
alpha--0.071
n = 3.5
J[T) = exp(ea(l/(T + 273) - 1/(T0+ 273)))
ea--5500°K
To •=• 200°C
/(PPwater) = (26.2 * PPwater/PSat +1.14)* 0.175, for T > 180°C (453°K)
./(PPwater) = ((26.2 + 0.272 * (180 - T)) * PPWater/Psat + 1.14) * 0.175,
for 180°C (453°K) > T > 150°C (433°K)
Psat = Saturation pressure of water at T (psia).
[0034] In one embodiment of the invention, the reaction system is started
up by loading activated catalyst into the reaction system so that the activated
molecular sieve portion of the catalyst does not contact or adsorb any significant
amount of water molecules. Then, the activated catalyst is heated and feed
introduced into the reactor system. The activated catalyst is heated to a
temperature effective to convert the feed to product upon contact of the feed with
the activated catalyst.
[0035] Preferably, the activated catalyst is loaded and maintained in the
reaction system at a temperature greater than or equal to water critical temperature
(i.e., 374°C). At water critical temperature and above, water cannot be liquefied,
so water adsorption will be minimized. There is no upper limit to the temperature,
except to a practical extent of unit operations. For exstnule, a practical
temperature limit is generally one not greater than about 1,000°C, preferably not
greater than about 900°C, more preferably not greater than about 800°C.
[0036] At temperatures below water critical temperature, water adsorption
can occur. However, at temperatures reasonably close to water critical
temperature, water adsorption is not significant. In one embodiment of the
invention, the activated catalyst is loaded and maintained in the reaction system at
a temperature of at least 300°C. In another embodiment, the activated catalyst is
loaded and maintained in the reaction system at a temperature of at least 325°C.
[0037] The activated molecular sieve can be loaded into and maintained in
the reaction system at lower temperatures. For example at temperatures in the
range of from about 150°C to about 300°C, or in the range of from about 160°C to
about 280°C, or in the range of from about 180°C to about 260°C. However, the
activated catalyst is loaded and maintained in the reaction system for a time, and
under water partial pressure conditions that do not significantly deactivate the
catalyst. Preferably, the activated catalyst is loaded into the reaction system and
maintained in the reaction system at conditions effective to maintain a catalytic
activity index (CAI) at a predetermined level where the catalyst is catalytically
effective to convert feed to desired end product. Preferably the activated catalyst
is loaded into the reaction system and maintained in the reaction system at
conditions effective to maintain a catalytic activity index of at least 0.7. More
preferably, the activated molecular sieve is loaded into the reaction system and
maintained in the reaction system at conditions effective to maintain a catalytic
activity index of at least 0.8, and most preferably a catalytic activity index of at
least 0.9.
[0038] Adsorption of water by activated molecular sieve can occur in
situations where the catalyst is contained in the reaction system at a temperature
lower than water critical temperature and the system contains at least a measurable
amount of water, i.e., a condition in which the reaction system is not considered
completely dry. The amount of water in the gas can be effectively determined
according to the relative water pressure of the gas in the reaction system. Relative
water pressure (Pr) in this invention is defined as actual partial pressure of the
water (PPwater) divided by saturated water pressure (P.,8l) at a given temperature
below the critical temperature of water. The relative water pressure is a measure
of the wetness of the environment in which the activated molecular sieve is
contacted with the gas. For example, a Pr = 1 means 100% water saturation, and a
Pr = 0 means that the gas or environment is completely dry.
[0039] In this invention relative water pressure of the reaction system into
which the activated catalyst is loaded can range from very low, i.e., low humidity
conditions, to a value of 1, saturated water conditions. For example, at 205°C, if
the activated catalyst is contacted with room air (at 23°C and at 71% relative
humidity), this air contains water at a partial pressure of 0.29 psia (71/100 * 0.41
= 0.29, where 0.41 psia is the saturation water pressure at 23°C). When this air is
heated up to 205°C, the relative water pressure becomes 0.29/250 = 0.00116,
10
where 250 psia is the saturation water pressure at 205°C. The relative humidity of
the gas at 205°C is 0.00116 * 100 = 0.116%. This example illustrates that one can
use high humidity room air as a heating medium at elevated temperature to
provide an environment having a low relative water pressure.
[0040] In general, the higher the water pressure, the greater the tendency
of the activated catalyst to adsorb water, given constant catalyst exposure
temperature and time of gas contact. The greater the amount of water adsorbed,
the higher the rate of catalyst deactivation. Nevertheless, by increasing
temperature or lowering time of contact, increased water pressure can be tolerated.
This is particularly beneficial, since it would be extremely difficult to start up a
reaction system, keeping the system completely dry. Thus, in one embodiment of
the invention, the reaction system into which the activated sieve is loaded (i.e., the
gas environment of the sieve) has a relative water pressure of at least 0.0001. In
another embodiment, the reaction system has a relative water pressure of at least
0.001; in another, a relative water pressure of at least 0.01, and in yet another a
relative water pressure of at least 0.1.
[0041 ] In another embodiment of the invention, the water partial pressure
of the reaction system, particularly the portion of the reaction system into which
the activated catalyst is loaded, is controlled so that activated molecular sieve
adsorbs little to no water. Preferably, the water partial pressure of the reaction
system, particularly the portion of the reaction system into whirh the activated
catalyst is loaded, is controlled so that activated molecular sieve has a water
content of not greater than about 1.25 wt %, based on dry weight of the activated
molecular sieve. More preferably, the activated molecular sieve has a water
content of not greater than about 1.0 wt %, still more preferably not greater than
about 0.8 wt %, and most preferably not greater than about 0.5 wt %, based on
total weight of the activated molecular sieve.
IL Type of Reaction Systems Encompassed by the Invention
[0042] The start up methods of this invention are useful in any reaction
system that involves the use of catalyst that comprises molecular sieve susceptible
to loss of catalytic activity due to contact with water molecules. Non-limiting
examples of such reaction systems include reaction systems selected from the
11
group consisting of catalytic cracking reaction systems, transalkylation reaction
systems, isomerization reaction systems, catalytic dewaxing systems, alkylation
reaction systems, hydrocracking reaction systems, systems for converting
paraffins to olefms, systems for converting paraffins to aromatics, systems for
converting olefms to gasoline, systems for converting olefms to distillate, systems
for converting olefms to lubes, systems for converting alcohols to olefms,
disproportionation reaction systems, systems for converting aromatics to higher
aromatics, systems for adsorbing aromatics, systems for converting oxygenates
(e.g., alcohols) to olefms, systems for converting oxygenates (e.g., alcohols) to
aromatics, systems for oligomerizing olefins, and systems for converting
unsaturated hydrocarbons to aldehydes. More specificially, such examples
include:
[0043] A) The catalytic cracking of a naphtha feed to produce light
olefms. Typical reaction conditions include from about 500°C to about 750°C,
pressures of subatmospheric or atmospheric, generally ranging up to about 10
atmospheres (gauge) and residence time (time of contact of feed and/or product
with catalyst) from about 10 milliseconds to about 10 seconds;
[0044] B) The catalytic cracking of high molecular weight
hydrocarbons to lower weight hydrocarbons. Typical reaction conditions for
catalytic cracking include temperatures of from about 400°C to about 700°C,
pressures of from about 0.1 atmosphere (bar) to about 30 atmospheres, and weight
hourly space velocities of from about 0.1 hr"1 to about 100 hr"1;
[0045] C) The transalkylation of aromatic hydrocarbons in the
presence of polyalkylaromatic hydrocarbons. Typical reaction conditions include
a temperature of from about 200°C to about 500°C, a pressure of from about
atmospheric to about 200 atmospheres, a weight hourly space velocity of from
about 1 hr"1 to about 100 hr"1, and an aromatic hydrocarbon/polyalkylaromatic
hydrocarbon mole ratio of from about 1/1 to about 16/1;
[0046] D) The isomerization of aromatic (e.g., xylene) feedstock
components. Typical reaction conditions for such include a temperature of from
about 230°C to about 510°C, a pressure of from about 0.5 atmospheres to about 50
12
atmospheres, a weight hourly space velocity of from about 0.1 hr"1 to about
200 hr"1, and a hydrogen/hydrocarbon mole ratio of from about 0 to about 100/1;
[0047] E) The catalytic dewaxing of hydrocarbons by selectively
removing straight chain paraffins. The reaction conditions are dependent in large
measure on the feed used and upon the desired pour point. Typical reaction
conditions include a temperature between about 200°C and 450°C, a pressure of
up to 3,000 psig and a liquid hourly space velocity from 0.1 hr"1 to 20 hr"1.
[0048] F) The alkylation of aromatic hydrocarbons, e.g., benzene and
alkylbenzenes, in the presence of an alkylating agent, e.g., olefins, formaldehyde,
alkyl halides and alcohols having 1 to about 20 carbon atoms. Typical reaction
conditions include a temperature of from about 100°C to about 500°C, a pressure
of from about atmospheric to about 200 atmospheres, a weight hourly space
velocity of from about 1 hr"1 to about 100 hr"1, and an aromatic
hydrocarbon/alkylating agent mole ratio of from about 1/1 to about 20/1;
[0049] G) The alkylation of aromatic hydrocarbons, e.g., benzene,
with long chain olefins, e.g., Cu olefin. Typical reaction conditions include a
temperature of from about 50°C to about 200°C, a pressure of from about
atmospheric to about 200 atmospheres, a weight hourly space velocity of from
about 2 hr"1 to about 2000 hr"1, and an aromatic hydrocarbon/olefin mole ratio of
from about 1/1 to about 20/1. The resulting products from the reaction are long
chain alkyl aromatics, which when subsequently sulfonated have particular
application as synthetic detergents;
[0050] H) The alkylation of aromatic hydrocarbons with light olefins
to provide short chain alkyl aromatic compounds, e.g., the alkylation of benzene
with propylene to provide cumene. Typical reaction conditions include a
temperature of from about 10°C to about 200°C, a pressure of from about 1 to
about 30 atmospheres, and an aromatic hydrocarbon weight hourly space velocity
(WHSV) of from 1 hr"1 to about 50 hr"1;
[0051 ] I) The hydrocracking of heavy petroleum feedstocks, cyclic
stocks, and other hydrocrack charge stocks. The catalyst will contain an effective
amount of at least one hydrogenation component;
13
[0052] J) The alkylation of a reformate containing substantial
quantities of benzene and toluene with fuel gas containing short chain olefins
(e.g., ethylene and propylene) to produce mono- and dialkylates. Preferred
reaction conditions include temperatures from about 100°C to about 250°C, a
pressure of from about 100 psig to about 800 psig, a WHSV-olefin from about
0.4 hr"1 to about 0.8 hr"1, a WHSV-reformate of from about 1 hr"1 to about 2 hr"1
and, optionally, a gas recycle from about 1.5 to about 2.5 vol/vol fuel gas feed;
[0053] K) The alkylation of aromatic hydrocarbons, e.g., benzene,
toluene, xylene, and naphthalene, with long chain olefins, e.g., Cu olefin, to
produce alkylated aromatic lube base stocks. Typical reaction conditions include
temperatures from about 100°C to about 400°C and pressures from about 50 psig
to 450 psig;
[0054] L) The alkylation of phenols with olefins or equivalent
alcohols to provide long chain alkyl phenols. Typical reaction conditions include
temperatures from about 100°C to about 250°C, pressures from about 1 to 300 psig
and total WHSV of from about 2 hr'1 to about 10 hr"1;
[0055] M) The conversion of light paraffins to olefins and/or
aromatics. Typical reaction conditions include temperatures from about 425°C to
about 760°C and pressures from about 10 psig to about 2000 psig;
[0056] N) The conversion of light olefins to gasoline, distillate and
lube range hydrocarbons. Typical reaction conditions include temperatures of
from about 175°C to about 375°C, and a pressure of from about 100 psig to about
2000 psig;
[0057] O) Two-stage hydrocracking for upgrading hydrocarbon
streams having initial boiling points above about 200°C to premium distillate and
gasoline boiling range products or as feed to further fuels or chemicals processing
steps. Either stage of the two-stage system can contain catalyst, which contains
molecular sieve that is susceptible to loss of catalytic activity due to contact with
water molecules. Typical reaction conditions include temperatures of from about
315°C to about 455°C, pressures of from about 400 to about 2500 psig, hydrogen
circulation of from about 1000 SCF/bbl to about 10,000 SCF/bbl and a liquid
hourly space velocity (LHSV) of from about 0.1 hr"1 to 10 hr"1;
14
[0058] P) A combination hydrocracking/dewaxing process in the
presence of a catalyst that contains molecular sieve that is susceptible to loss of
catalytic activity due to contact with water molecules. The catalyst generally
further comprises a hydrogenation component. Optionally included in the catalyst
is zeolite molecular sieve such as zeolite Beta. Typical reaction conditions include
temperatures from about 350°C to about 400°C, pressures from about 1400 psig to
about 1500 psig, LHSVs from about 0.4 hr'1 to about 0.6 hr"1 and a hydrogen
circulation from about 3000 to about 5000 SCF/bbl;
[0059] Q) The reaction of alcohols with olefms to provide mixed
ethers, e.g., the reaction of methanol with isobutene and/or isopentene to provide
methyl-t-butyl ether (MTBE) and/or t-amyl methyl ether (TAME). Typical
conversion conditions include temperatures from about 20°C to about 200°C,
pressures from 2 to about 200 atm, WHSV (gram-olefm per hour gram-zeolite)
from about 0.1 hr"1 to about 200 hr"1 and an alcohol to olefin molar feed ratio from
about 0.1/1 to about 5/1;
[0060] R) The disproportionation of aromatics, e.g., the
disproportionation toluene to make benzene and paraxylene. Typical reaction
conditions include a temperature of from about 200°C to about 760°C, a pressure
of from about atmospheric to about 60 atmosphere (bar), and a WHSV of from
about 0.1 hr"1 to about 30 hr"1;
[0061] S) The conversion of naphtha (e.g., Cs-Cio) and similar
mixtures to highly aromatic mixtures. Thus, normal and slightly branched chained
hydrocarbons, preferably having a boiling range above about 40°C, and less than
about 200°C, can be converted to products having a substantially higher octane
aromatics content by contacting the hydrocarbon feed with a molecular sieve
catalyst at a temperature of from about 400°C to 600°C, preferably from about
480°C to about 550°C, at pressures of from atmospheric to 40 bar, and liquid
hourly space velocities (LHSV) of from 0.1 hr"1 to 15 hr"1;
[0062] T) The adsorption of alkyl aromatic compounds for the
purpose of separating various isomers of the compounds;
[0063] U) The conversion of oxygenates, e.g., alcohols, such as
methanol, or ethers, such as dimethylether, or mixtures thereof to hydrocarbons
15
including olefins and aromatics with reaction conditions including temperatures of
from about 275°C to about 600°C, pressures of from about 0.5 atmosphere to
about 50 atmospheres, and a liquid hourly space velocity of from about 0.1 hr'1 to
about 100 hr"1;
[0064] V) The oligomerization of straight and branched chain olefins
having from about 2 to about 5 carbon atoms. The oligomers which are the
products of the process are medium to heavy olefins which are useful for both
fuels, i.e., gasoline or a gasoline blending stock, and chemicals. The
oligomerization process is generally carried out by contacting the olefin feedstock
in a gaseous state phase with a molecular sieve catalyst at a temperature in the
range of from about 250°C to about 800°C, a LHSV of from about 0.2 hr"1 to about
50 hr"1, and a hydrocarbon partial pressure of from about 0.1 to about 50
atmospheres. Temperatures below about 250°C may be used to oligomerize the
feedstock when the feedstock is in the liquid phase when contacting the coated
zeolite catalyst. Thus, when the olefin feedstock contacts the catalyst in the liquid
phase, temperatures of from about 10°C to about 250°C may be used;
[0065] W) The conversion of €2 unsaturated hydrocarbons (ethylene
and/or acetylene) to aliphatic Ce-12 aldehydes and converting said aldehydes to the
corresponding C^-u alcohols, acids, or esters.
[0066] hi general, the, catalytic conversion conditions over the molecular
sieve catalyst include a temperature of from about 100°C to about 760°C, a
pressure of from about 0.1 atmosphere (bar) to about 200 atmospheres (bar), a
weight hourly space velocity of from about 0.08 hr"1 to about 2,000 hr"1.
[0067] The start up methods of this invention are particularly suited to
large, commercial scale reaction systems. For example, the start up methods of
this invention are particularly suited to reaction systems that require a catalyst
loading of at least about 1,000 kg of catalyst, based on total amount of catalyst
located throughout the reaction system. In particular, the start up methods of this
invention are particularly suited to reaction systems that require a catalyst loading
of at least about 10,000 kg of catalyst, more particularly a catalyst loading of at
least about 100,000 kg of catalyst, and most particularly a catalyst loading of at
16
least about 250,000 kg of catalyst, based on total amount of catalyst located
throughout the reaction system.
J0068} The catalyst loaded into the reaction system need not be fully
comprised of a molecular sieve that is susceptible to loss of catalytic activity due
to contact with water molecules. The catalyst need contain only an amount of
such molecular sieve that materially affects the desired product slate. For
example, in one embodiment, the catalyst loaded into the system comprises at
least about 1 wt % of a molecular sieve that is susceptible to loss of catalytic
activity due to contact with water molecules, based on total weight of catalyst
loaded into the system. In anther embodiment, the catalyst loaded into the system
comprises at least about 5 wt % of a molecular sieve that is susceptible to loss of
catalytic activity due to contact with water molecules, based on total weight of
catalyst loaded into the system; in another embodiment at least about 10 wt %,
based on total weight of catalyst loaded into the system.
J0069] In terms of feed to the system, the start up methods of this
invention are particularly suited to reaction systems that are rated at a total liquid
throughput of at least about 500 barrels per day. More particularly, the start up
methods of this invention are suited to reaction systems that are rated at a total
liquid throughput of at least about 1,000 barrels per day, still more particularly at
least about 5,000 barrels per day, and most particularly at least about 10,000
barrels per day.
f 0070] The liquid feed that is to the reaction system to start up the system
is any conventional hydrocarbon feed that is appropriate to the unit being started
up. Non-limiting examples of such feed includes hydrocarbon oils such as
kerosenes, naphthas, diesels, light or heavy gas oils, vacuum distillates or residua,
light cycle oils, heavy cycle oils; aromatics such as benzenes, xylenes, toluenes,
naphthalenes,; and alcohols, including monoaJcohols or polyols, particularly QCio
monoalcohols (especially methanol, ethanol and propanol) and Cs-Cjo polyols.
[0071] The catalyst loaded into the system can be of any conventional
shape or size, including, but not limited to, those catalyst types made by spray
drying, peiletizing, extrusion, and any of various conventional sphere-making
techniques. The molecular sieve contained in the catalyst can be incorporated into
17
each catalyst particle or catalyst particles containing the molecular sieve can be
admixed with other catalyst particles that do not contain molecular sieve.
[0072] The reaction systems into which the catalyst is loaded contain a
reactor unit. Optionally, the reaction systems contain two or more reactor units.
The reactor units can be in series or parallel. Non-limiting examples of reaction
systems which can be started up according to this invention include dense bed
reaction systems, fixed bed reaction systems, fluidized bed reaction systems, fast
fluidized bed reaction systems, circulating fluidized bed reaction systems, riser
reactor systems, and the like. Suitable conventional reaction systems and reactor
types are described in for example U.S. Patent No. 4,076,796, U.S. Patent No.
6,287,522 (dual riser), and Fluidization Engineering, D. Kunii and O. Levenspiel,
Robert E. Krieger Publishing Company, New York, New York 1977, which are all
herein fully incorporated by reference. Other examples of reaction systems
include riser reactors, such as those 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. Patent No.
6,166,282 (fast-fluidized bed reactor), and U.S. Patent Application Serial No.
09/564,613 filed May 4, 2000 (multiple riser reactor), which references are all
herein fully incorporated by reference.
[0073] In a preferred embodiment, a fluidized bed process or fast fluidized
bed process includes a reactor system, a regeneration system and a recovery
system. The reactor system preferably is 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, preferably comprising one or more
cyclones. In one embodiment, the one or more riser reactor(s) and disengaging
vessel is contained within a single reactor vessel. Fresh feedstock is fed to the one
or more riser reactor(s) in which an activated molecular sieve catalyst composition
is introduced.
[0074] In another embodiment, the reaction systems, which are started up
according to this invention, further include a regenerator unit. Optionally, the
reaction systems include two or more regenerator units. The regenerator units are
18
in connection with at least one of the reactor units, preferably in a manner that
allows catalyst to be circulated or flowed between the reactor and regenerator.
IIL Loading Catalyst and Heating Up the Reaction System
[0075] In one embodiment of the invention, at least a portion of the
reaction system is heated prior to loading of the catalyst. In a particular
embodiment, at least the portion of the reaction system that is heated prior to
catalyst loading is heated to at least about 150°C prior to catalyst loading. In
another embodiment, at least the portion of the reaction system that is heated prior
to catalyst loading is heated to at least about 200°C prior to catalyst loading.
Preferably, at least the portion of the reaction system that is heated prior to catalyst
loading is heated to at least about 300°C, most preferably to a temperature at least
that of water critical temperature, prior to catalyst loading.
[0076] The portion of the reaction system that is heated is optionally held
at a temperature effective to heat and/or dry refractory material that is present in
the reaction system. For example, the reaction system can are typically held at a
temperature of from about 200°C to about 450°C, but preferably without catalyst
present when the holding temperature is below water critical temperature (374°C).
Such refractory material can be any conventional material used in reaction
systems. Preferably, the refractory materials are sufficiently dried prior to
introduction of catalyst, since water molecules will tend to be released from the
refractory material during the drying process, Tn one embodiment, at least a
portion of the reaction system is heated for about 2 hours to about 48 hours prior
to catalyst loading. Preferably, at least a portion of the reaction system is heated
for about 4 hours to about 24 hours, more preferably from about 6 hours to about
12 hours prior to catalyst loading.
[0077] The reaction system can be a hot wall or cold wall reactor system.
In one embodiment, the reaction system is a hot wall reactor system. Hot wall
systems use refractory materials that are thinner than that of cold wall systems,
and, therefore, would release less water during dry out. In another embodiment,
the reaction system is a cold wall reaction system. The cold wall reaction systems
use thicker refractory materials, but the thicker refractory allows the reactor itself
19
to be thinner, since the cold wall material can handle a greater heat load during
unit operation.
[0078] The catalyst that is loaded into the reaction system is to be
maintained so that any loss of catalytic activity is not significant, preferably
limiting catalyst loss to a predetermined catalytic activity index. In one
embodiment, the catalyst is maintained in the reaction system at a catalytic
activity index of at least about 0.7, preferably at least about 0.8, and more
preferably at least about 0.9.
10079] In a particular embodiment, the catalyst is loaded into the reactor
unit of the reaction system. Optionally, the reaction system contains a reactor unit
and a regenerator unit, and the catalyst is loaded into the regenerator unit.
10080] The activated catalyst is loaded into the reactor or regenerator unit
in any conventional manner. For example, the catalyst is loaded directly into the
reactor or regenerator unit through openings on the units or vessels. In one
embodiment, the catalyst is loaded into the reactor or regenerator through an
upper portion of the vessels. In another embodiment, the catalyst is loaded into
the reactor or regenerator through a bottom portion of the units or vessels.
Loading can be accomplished with the aid of hoppers and conduits positioned to
feed the catalyst into the particular unit.
[0081] In an alternative embodiment of the invention, the catalyst loaded
into the reaction system is further heated, preferably after a predetermined level of
catalyst has been added. The additional heating provides further protection
against deactivation of the activated molecular sieve that is susceptible to
deactivation due to contact with water molecules. Preferably, the loaded catalyst
is heated to a temperature that is at least about 100°C higher than when first
loaded into the reaction system, more preferably at least about 150°C, and most
preferably at least about 200°C.
[0082] In another embodiment, the catalyst loaded into the reaction system
is further heated to a temperature of at least about 300°C. Preferably, the catalyst
loaded into the reaction system is further heated to a temperature of at least about
400°C, more preferably a temperature of at least about 450°C, and most preferably
to a temperature of at least about 500°C.
20
[0083] In general, at relatively low temperatures, the catalyst is to be
maintained in the reaction system for only a limited time. Otherwise, the catalytic
activity of the molecular sieve may become significantly deactivated. Desirably,
at temperatures not greater than about 300°C, more particularly not greater than
about water critical temperature, the catalyst is maintained in the reaction system
for a time to maintain the catalytic activity index at or above the desired level. In
general, the catalyst containing the activated molecular sieve is maintained in the
reaction system (e.g., the reaction unit or regenerator unit) at such temperatures
for not greater than about 500 hours. Preferably, the catalyst containing the
activated molecular sieve is maintained at such temperatures in the reaction
system for not greater than about 250 hours, more preferably not greater than
about 100 hours. In other embodiments, the catalyst containing the activated
molecular sieve is maintained in the reaction system at such temperatures from
about 0.01 hour to about 50 hours, or from about 0.1 hour to about 50 hours, and
more preferably not greater than about 24 hours or about 12 hours or about
6 hours. As the system is heated to higher temperatures, the catalyst can be
maintained in the system indefinitely without significant reduction in catalytic
activity as a result of contact with water molecules.
[0084] The reaction system can be heated using any conventional gas as a
heating medium. Non-limiting examples of such gas include air, nitrogen, helium,
flue gas, CO? fuel gas, and any combination thereof. Air is most preferred, as air
is generally used in various unit start up operations.
[0085] The gas that is used as the heating medium is preferably dry.
However, the gas does not have to be completely dry as such a condition is not
generally practical at commercial scale. In one embodiment of the invention, the
gas contacting the sieve (i.e., the gas environment of the sieve) has a relative
water pressure of at least 0.0001. In another embodiment, the gas containing
water has a relative water pressure of at least 0.001; in another, a relative water
pressure of at least 0.01, and in yet another a relative water pressure of at least 0.1.
[0086] In certain embodiments, air containing water (i.e., steam) can be
used at either saturated conditions or at superheated steam conditions. For
example, air containing a higher proportion of water can be used to initially heat
21
at least a portion of the reaction system, prior to loading the catalyst. Such an
initial heating of the reaction system can more quickly heat the system, since the
water has a greater ability to transfer heat than air or other gas.
[0087] To further heat the catalyst or reaction system a combustion or
hydrocarbon fuel can be used. The combustion of a fuel to provide additional heat
can be beneficial in circumstances where gas (e.g., air, nitrogen, helium, flue gas,
CC>2, fuel gas, and any combination thereof) or gas including water vapor (i.e.,
steam) does not have sufficient heat to bring the catalyst to start up temperatures.
Once an effective start up temperature is achieved, feed is introduced into the
reaction system, and the feed contacts the heated catalyst to begin the reaction
process.
(0088] In a particular embodiment, a hydrocarbon oil, such as for example
kerosene, naphtha, light cycle oil, light virgin diesel, torch oil, or the like, is used
as a fuel to further heat the loaded catalyst. Such fuels can be injected through
nozzles into a loaded bed of catalyst and combusted. Preferably, the hydrocarbon
oil is injected into the reaction system after the reaction system has been initially
heated to a temperature that is at least as high as the auto-ignition temperature of
the hydrocarbon oil to further increase the temperature of the reaction system,
preferably to at least operating temperature of the particular reaction system. In
one embodiment, the hydrocarbon oil is injected into the system after the system
has reached a temperature of at least about 350°C, preferably at least about 375°C,
and more preferably at least about 400°C. Upon combustion of the hydrocarbon
oil, the temperature of the reaction system is further increased, preferably to at
least the operating temperature of the reaction process.
[0089] In one embodiment, the reaction system includes at least two
reaction units or one or more reaction units and one or more regenerator units, and
the heated catalyst is circulated between units to aid in heating the reaction
system. Preferably, the reaction system contains a reactor unit and a regenerator
unit, and the heated catalyst is circulated between the units to further heat the
system. In one embodiment, the heated catalyst is circulated to the regenerator
unit using a lift gas such as air, nitrogen, helium, flue gas, COj, fuel gas, and any
combination thereof. In another embodiment, the heated catalyst is circulated at a
22
temperature that is at least as high as operating temperature. In another
embodiment, a gas or gas including water vapor is used to heat the catalyst,
particularly in the reactor unit, and a hydrocarbon oil is injected into the
regenerator unit to further heat the catalyst, while circulating, as described above.
Once the reaction system or catalyst is sufficiently heated to operating
temperature, feed is introduced into the reactor unit, and the reaction process is
started.
IV. Types of Molecular Sieves
[0090] The catalyst that is used in the methods of this invention contains
molecular sieve material that is susceptible to deactivation due to contact with
water molecules. The molecular sieves that are included in the catalyst or catalyst
mixtures are preferably metalloaluminophosphate molecular sieves that have a
molecular framework that include [A1O4] and [PO4] tetrahedral units, such as
metal containing aluminophosphates (A1PO). In one embodiment, the
metalloaluminophosphate molecular sieves include [A1O4], [PO4] and [SiO4]
tetrahedral units, such as silicoaluminophosphates (SAPO).
[0091] Various 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. Patent No. 4,567,029 (MeAPO
where Me is Mg, Mn, Zn, or Co), U.S. Patent No. 4,440,871 (SAPO), European
Patent Application EP-A-0 ! 59 624 (ELAPSO where v.l is A.s, Be, B; Cr, Co, Ga,
Ge, Fe, Li, Mg, Mn, Ti or Zn), U.S. Patent No. 4,554,143 (FeAPO), U.S. Patents
No. 4,822,478, 4,683,217, 4,744,885 (FeAPSO), EP-A-0 158 975 and U.S. Patent
No. 4,935,216 (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. Patent No. 4,310,440 (A1PO4), EPA-
0 158 350 (SENAPSO), U.S. Patent No. 4,973,460 (LiAPSO), U.S. Patent No.
4,789,535 (LiAPO), U.S. Patent No. 4,992,250 (GeAPSO), U.S. Patent No.
4,888,167 (GeAPO), U.S. Patent No. 5,057,295 (BAPSO), U.S. Patent No.
4,738,837 (CrAPSO), U.S. Patents Nos. 4,759,919, and 4,851,106 (CrAPO), U.S.
Patents Nos. 4,758,419, 4,882,038, 5,434,326 and 5,478,787 (MgAPSO), U.S.
Patent No. 4,554,143 (FeAPO), U.S. Patent No. 4,894,213 (AsAPSO), U.S. Patent
No. 4,913,888 (AsAPO), U.S. Patents Nos. 4,686,092, 4,846,956 and 4,793,833
23
(MnAPSO), U.S. Patents Nos. 5,345,011 and 6,156,931 (MnAPO), U.S. Patent
No. 4,737,353 (BeAPSO), U.S. Patent No. 4,940,570 (BeAPO), U.S. Patents Nos.
4,801,309,4,684,617 and 4,880,520 (TiAPSO), U.S. Patents Nos. 4,500,651,
4,551,236 and 4,605,492 (TiAPO), U.S. Patents No. 4,824,554, 4,744,970
(CoAPSO), U.S. Patent No. 4,735,806 (GaAPSO) EP-A-0 293 937 (QAPSO,
where Q is framework oxide unit [Q02]), as well as U.S. Patents Nos. 4,567,029,
4,686,093, 4,781,814, 4,793,984, 4,801,364, 4,853,197,4,917,876, 4,952,384,
4,956,164,4,956,165, 4,973,785, 5,241,093, 5,493,066 and 5,675,050, all of
which are herein fully incorporated by reference. Other molecular sieves include
those described in R. Szostak, Handbook of Molecular Sieves, Van Nostrand
Reinhold, New York, New York (1992), which is herein fully incorporated by
reference.
[0092] The more preferred molecular sieves are SAPO molecular sieves,
and metal-substituted SAPO molecular sieves. Suitable metal substituents are
alkali metals of Group LA 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 1IIB, 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, VLB, VIIB, VIILB, 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 [Me02], 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.
[0093] In one embodiment, the metalloaluminophosphate molecular sieve
is represented, on an anhydrous basis, by the formula:
mR:(MxAlyPz)02
24
wherein R represents at least one templating agent, preferably an organic
templating agent; m is the number of moles of R per mole of (MxAlyPz)02 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 the group consisting of Group IA, HA, IB, IIIB, IVB, VB,
VIB, Vim, VIIIB and Lanthanide's of the Periodic Table of Elements. Preferably
M is one or more metals selected from 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.
[0094] In one embodiment of the invention, the metalloaluminophosphate
molecular sieves are silicoaluminophosphate molecular sieves, containing silicon
and aluminum. In general, lower Si/Al ratios lead to lower deactivation rates and
higher ACls for a given set of conditions. However, higher Si/Al ratios can be
used under the appropriate conditions of temperature, water partial pressure and
time of contact with water. Desirably, the metalloaluminophosphate molecular
sieves of this invention are silicoaluminophosphate molecular sieves that contain
Si and Al, at a Si/A! ratio of not greater than about 0.5, preferably not greater than
about 0.3, more preferably not greater than about 0.2, still more preferably not
greater than about 0.15, and most preferably not greater than about 0.1. In another
embodiment, the Si/Al ratio is sufficiently high to allow for increased catalytic
activity of the molecular sieve. Preferably, the metalloaluminophosphate
molecular sieves are silicoaluminophosphate molecular sieves that contain Si and
Al at a ratio of at least about 0.005, more preferably at least about 0.01, and most
preferably at least about 0.02.
[0095] Non-limiting examples of SAPO and A1PO molecular sieves useful
herein include one or a combination 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,
25
A1PO-5, A1PO-11, A1PO-18, A1PO-31, A1PO-34, A1PO-36, A1PO-37, A1PO-46,
and metal containing molecular sieves thereof. Of these, particularly useful
molecular sieves are one or a combination of SAPO-18, SAPO-34, SAPO-35,
SAPO-44, SAPO-56, A1PO-18, A1PO-34 and metal containing derivatives thereof,
such as one or a combination of SAPO-18, SAPO-34, A1PO-34, A1PO-18, and
metal containing derivatives thereof, and especially one or a combination of
SAPO-34, A1PO-18, and metal containing derivatives thereof.
|0096] hi an 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 April 16, 1998, both of which are herein fully
incorporated by reference. For example, SAPO-18, A1PO-18 and RUW-18 have
an AE1 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.
[0097] Generally, molecular sieves (i.e., molecular sieve crystals) are
synthesized by the hydrothermal crystallization of one or more of a source of
aluminum, a source of phosphorus, a source of silicon, water and a ternplating
agent, such as a nitrogen containing organic compound. Typically, a combination
of sources of silicon and aluminum, or silicon, aluminum and phosphorus, water
and one or more templating agents, is placed in a sealed pressure vessel. The
vessel is optionally lined with an inert plastic such as polytetrafluoroethylene, and
heated under a crystallization pressure and temperature, until a crystalline material
is formed, which can then be recovered by filtration, centrifugation and/or
decanting.
|0098] Non-limiting examples of silicon sources include silicates, fumed
silica, for example, Aerosil-200 available from Degussa Inc., New York, New
York, and CAB-O-SIL M-5, organosilicon compounds such as
tetraalkylorthosilicates, for example, tetramethylorthosilicate (TMOS) and
26
tetraethylorthosilicate (TEOS), colloidal silicas or aqueous suspensions thereof,
for example Ludox-HS-40 sol available from E.I. du Pont de Nemours,
Wilmington, Delaware, silicic acid or any combination thereof.
[0099] Non-limiting examples of aluminum sources include aluminum
alkoxides, for example aluminum isopropoxide, aluminum phosphate, aluminum
hydroxide, sodium aluminate, pseudo-boehmite, gibbsite and aluminum
trichloride, or any combination thereof. A convenient source of aluminum is
pseudo-boehmite, particularly when producing a silicoaluminophosphate
molecular sieve.
[0100] Non-limiting examples of phosphorus sources, which may also
include aluminum-containing phosphorus compositions, include phosphoric acid,
organic phosphates such as triethyl phosphate, and crystalline or amorphous
aluminophosphates such as AlPCU, phosphorus salts, or combinations thereof. A
convenient source of phosphorus is phosphoric acid, particularly when producing
a silicoaluminophosphate.
[0101] In general, templating agents or templates include compounds that
contain elements of Group 15 of the Periodic Table of Elements, particularly
nitrogen, phosphorus, arsenic and antimony. Typical templates also contain at
least one alkyl or aryl group, such as an alkyl or aryl group having from 1 to 10
carbon atoms, for example from 1 to 8 carbon atoms. Preferred templates are
nitrogen-containing compounds, such as amines, quaternary ammonium
compounds and combinations thereof. Suitable quaternary ammonium
compounds are represented by the general formula I^N*, where each R is
hydrogen or a hydrocarbyl or substituted hydrocarbyl group, preferably an alkyl
group or an aryl group having from 1 to 10 carbon atoms.
[0102] Non-limiting examples of templates include tetraalkyl ammonium
compounds including salts thereof, such as tetramethyl ammonium compounds,
tetraethyl ammonium compounds, tetrapropyl ammonium compounds, and
tetrabutylammonium compounds, cyclohexylamine, morpholine, di-npropylamine
(DPA), tripropylamine, triethylamine (TEA), triethanolamine,
piperidine, cyclohexylamine, 2-methylpyridine, N,N-dimethylbenzylamine, N,Ndiethylethanolamine,
dicyclohexylamine, N,N-dimethylethanolamine, choline,
27
N,N'-dimethylpiperazine, 1,4-diazabicyclo(2,2,2)octane, N1, N',N,N-tetramethyl-
(l,6)hexanediamine, N-methyldiethanolamine, N-methyl-ethanolamine, N-methyl
piperidine, 3-methyl-piperidine, N-methylcyclohexylamine, 3-methylpyridine, 4-
methyl-pyridine, quinuclidine, N,N'-dimethyl-l,4-diazabicyclo(2,2,2) octane ion;
di-n-butylamine, neopentylamine, di-n-pentylamine, isopropylamine, t-butylamine,
ethylenediamine, pyrrolidine, and 2-imidazolidone. Preferred templates
are selected from the group consisting of tetraethyl ammonium salts,
cyclopentylamine, aminomethyl cyclohexane, piperidine, triethylamine,
cyclohexylamine, tri-ethyl hydroxyethylamine, morpholine, dipropylamine
(DPA), pyridine, isopropylamine, heated degraded forms thereof, and
combinations thereof.
[0103] The pH of the synthesis mixture containing at a minimum a silicon,
aluminum, optionally a phosphorus composition, and a templating agent, is
generally in the range of from 2 to 10, such as from 4 to 9, for example from 5 to
8.
[0104] Generally, the synthesis mixture described above is sealed in a
vessel and heated, preferably under autogenous pressure, to a temperature in the
range of from about 80°C to about 250°C, such as from about 100°C to about
250°C, for example from about 125°C to about 225°C, such as from about 150°C
to about 180°C.
[0105] In one embodiment, the synthesis of roclecula" si*"/? crystalline
particles is aided by seeds from another or the same framework type molecular
sieve.
[0106] The time required to form the crystalline particles is usually
dependent on the temperature and can vary from immediately up to several weeks.
Typically, the crystallization time is from about 30 minutes to around 2 weeks,
such as from about 45 minutes to about 240 hours, for example from about 1 hour
to about 120 hours. The hydrothermal crystallization may be carried out with or
without agitation or stirring.
[0107] One method for crystallization involves subjecting an aqueous
reaction mixture containing an excess amount of a templating agent to
crystallization under hydrothermal conditions, establishing an equilibrium
28
between molecular sieve formation and dissolution, and then, removing some of
the excess templating agent and/or organic base to inhibit dissolution of the
molecular sieve. See, for example, U.S. Patent No. 5,296,208, which is herein
fully incorporated by reference.
[0108] Other methods for synthesizing molecular sieves or modifying
molecular sieves are described in U.S. Patent No. 5,879,655 (controlling the ratio
of the templating agent to phosphorus), U.S. Patent No. 6,005,155 (use of a
modifier without a salt), U.S. Patent No. 5,475,182 (acid extraction), U.S. Patent
No. 5,962,762 (treatment with transition metal), U.S. Patent Nos. 5,925,586 and
6,153,552 (phosphorus modified), U.S. Patent No. 5,925,800 (monolith
supported), U.S. Patent No. 5,932,512 (fluorine treated), U.S. Patent No.
6,046,373 (electromagnetic wave treated or modified), U.S. Patent No. 6,051,746
(polynuclear aromatic modifier), U.S. Patent No. 6,225,254 (heating template),
PCT WO 01/36329 published May 25, 2001 (surfactant synthesis), PCT WO
01/25151 published April 12, 2001 (staged acid addition), PCT WO 01/60746
published August 23, 2001 (silicon oil), U.S. Patent Application Publication No.
20020055433 published May 9, 2002 (cooling molecular sieve), U.S. Patent No.
6,448,197 (metal impregnation including copper), U.S. Patent No. 6,521,562
(conductive microfilter), and U.S. Patent Application Publication No.
20020115897 published August 22, 2002 (freeze drying the molecular sieve),
which are all herein fully incorporated by reference.
[0109] Once the crystalline molecular sieve product is formed, usually in a
slurry state, it may be recovered by any standard technique well known in the art,
for example, by centrifugation or filtration. The recovered crystalline particle
product, normally termed the "wet filter cake", may then be washed, such as with
water, and then dried, such as in air, before being formulated into a catalyst
composition. Alternatively, the wet filter cake may be formulated into a catalyst
composition directly, that is without any drying, or after only partial drying.
[0110| In one embodiment, the molecular sieve that is susceptible to
deactivation due to contact with water molecules is contained in a formulated
catalyst. In general, formulated molecular sieve catalyst optionally contains
binder and matrix materials. Conventionally, formulated catalyst is made by
29
mixing together molecular sieve crystals (which includes template) and a liquid,
optionally with matrix material and/or binder, to form a slurry. The slurry is then
dried (i.e., liquid is removed), without completely removing the template from the
molecular sieve. Since this dried molecular sieve catalyst includes template, it has
not been activated, and is considered a preformed catalyst. The catalyst in this
form is resistant to catalytic loss by contact with moisture or water. However, the
preformed catalyst must be activated before use, and this invention provides
appropriate methods to protect the activated catalyst from significant deactivation.
[0111] The liquid used to form the slurry 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.
[0112) Matrix materials are optionally included in the slurry used to make
the formulated 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 densify
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.
[0113] 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.
30
[0114] In a particular embodiment, the matrix material is a clay or a claytype
composition, preferably a clay or clay-type composition having a low iron or
titania content, and most preferably the matrix material is kaolin. Kaolin has been
found to form a purnpable, high solid content slurry; it has a low fresh surface
area, and it packs together easily due to its platelet structure.
[0115] Preferably, the matrix material, particularly clay, and preferably
kaolin, has an average particle size of from about 0.05 /mi to about 0.75 /mi; more
preferably from about 0.1 /mi to about 0.6 /mi. It is also desirable that the matrix
material have a dpo particle size distribution of less than about 1.5 /mi, preferably
less than about 1 /im.
[0116] Binders are also optionally included in the slurry used to make the
formulated molecular sieve catalysts of this invention. Such materials act like
glue, binding together the molecular sieve crystals 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 calcining, 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.
[0117] Aluminium chlorohydrate, a hydroxylated aluminium based sol
containing a chloride counter ion, also known as aluminium chlorohydrol, has the
general formula
AlmOn(OH)0Clp-x(H20)
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 Ali3O4(OH)24Clv'12(H2O) 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, 7-alumina, boehmite and transitional aluminas such as a-alumina,
31
0-alumina, 7-alumina, 5-alumina, e-alumina, K-alumina, and p-alumina,
aluminium trihydroxide, such as gibbsite, bayerite, nordstrandite, doyelite, and
mixtures thereof.
[0118] 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, Illinois, and Nyacol available from the Nyacol Nano
Technology Inc., Boston, Massachusetts.
[0119] If binder is not used in making the molecular sieve catalyst, the
catalyst is considered a binderless catalyst. If binder is used, the amount of binder
used to prepare the molecular sieve catalyst 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 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).
[0120] Where the catalyst composition contains a binder and a matrix
material, 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,
such 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.
32
[0121] 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 formulated molecular sieve catalyst composition.
[0122] The molecular sieve crystals are mixed with liquid, and the
optional matrix material and/or binder, using conventional techniques to form a
slurry. The components can be mixed in any order, and the mixture is thoroughly
stirred to form the slurry. The more thorough the stirring, the better the
consistency of the slurry.
[0123] The mixing of the slurry is preferably sufficient to break any
aggregates or large particles into smaller, more uniform particles. In general, the
more vigorous the mixing, the smaller the 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 3,000 rpm laboratory scale
equivalent.
[0124] 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.
[0125] In one embodiment, the slurry has a viscosity of from about 100 cP
(0.1 Pa/sec) to about 9,500 cP (9.5 Pa/sec), as measured using a Brookfield LVDVE
viscometer with a No. 3 spindle at 10 rpm. Preferably, the slurry has a
viscosity of from about 200 cP (0.2 Pa/sec) to about 8,500 cP (8.5 Pa/sec), and
more preferably from about 350 cP (0.375 Pa/sec) to about 8,000 cP (8 Pa/sec), as
measured using a Brookfield LV-DVE viscometer with a No. 3 spindle at 10 rpm.
[0126] hi another embodiment, the slurry has a solids content of from
about 10 wt % to about 75 wt %, based on total weight of the slurry. Preferably
the 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
33
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.
[0127] In one embodiment, the slurry used to make the formulated
molecular sieve catalyst contains binder and matrix material at a weight ratio of
from 0:1 to 1:1. Preferably, the slurry used to make the molecular sieve catalyst
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. In case where binders are
not used, the molecular sieve component itself acts as a binder.
[0128] In formulating the catalyst composition, the molecular sieve and
optional binder and/or matrix materials are initially combined in the presence of a
liquid to form a slurry typically containing from about 20 weight percent to about
90 weight percent, such as from about 25 weight percent to about 85 weight
percent, molecular sieve, based on total weight of the slurry. The liquid used to
form the slurry can, for example, be one or a combination of water, an alcohol, a
ketone, an aldehyde, and/or an ester, but normally will be water.
[0129] Liquid is removed from the slurry containing the molecular sieve
crystals to form a preformed molecular sieve catalyst. Preferably, the slurry is fed
to a forming unit that produces the preformed molecular sieve catalyst
composition. The forming unit may be any conventional unit, such as a spray
dryer, pelletizer, extnader, etc. In a preferred embodiment, the forming unit is
spray dryer, which removes water from the slurry by a heating or drying process.
Preferably, the forming unit is maintained at a temperature sufficient to remove a
majority of the liquid from the slurry.
[0130] When a spray dryer is used as the forming (or drying) unit,
typically, the slurry of the molecular sieve particles, and optional matrix material
and/or binder, is fed to the spray drying unit along with a drying gas. The drying
gas contacts the slurry and acts to remove water to form the preformed molecular
sieve catalyst. Conventional drying conditions can be used. Such conditions
include an average inlet temperature ranging from about 150°C to about 550°C,
and an average outlet temperature ranging from about 100°C to about 250°C.
34
|0131] During spray drying, the slurry is passed through a nozzle
distributing the slurry into small droplets, resembling an aerosol spray, into a
drying chamber where atomization occurs. 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 1,000 psia (about 690 kPaa to about 6,895
kPaa). In another embodiment, the slurry is fed through a single nozzle or
multiple nozzles along with an atomization or contacting fluid such as air, steam,
flue gas, or any other suitable gas.
[0132] In yet another embodiment, the slurry that is used to make the
preformed catalyst 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 drier to form a preformed
molecular sieve catalyst composition. An example of a conventional spray drying
process is described in U.S. Pat. No. 4,946,814, which is incorporated herein by
reference.
[0133] The molecular sieve material is activated by removing the template
from the preformed molecular sieve catalyst composition so as to expose the
active catalytic sites to the environment. The template can be removed by any
conventional technique, including for example by elution methods or by heating.
The molecular sieve crystals themselves can be activated for immediate catalytic
use or for storing or transporting prior to use. However, it is preferred that the
molecular sieves be formulated into a preformed catalyst, then activated, since the
sieves are typically most useful as a formulated product. The formulated product
generally provides the most effective particle size and hardness for commercial
scale equipment.
[0134] In one embodiment of the invention, the molecular sieve material is
activated by removing the template by heat. In a preferred embodiment, the heat
is sufficient to remove water that is formed as a result of the combustion of the
template. Preferably, the molecular sieve material is heated at a temperature
35
greater than the critical temperature of water. At this temperature, water formed
during the combustion process will not condense or be retained by the molecular
sieve. Preferably, the template is removed by contacting with steam at a
temperature greater than the critical temperature of water. More preferably,
following removal of the template, any water entrained in the catalyst is also
removed, preferably by appropriate heating using a dry gas. Preferably, the dry
gas has a relative water pressure of less than 0.0001.
[0135] Heating to remove template and activate the molecular sieve is
generally referred to in this invention as calcination. Conventional calcination
devices can be used. 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.
[0136] Conventional calcination temperatures are effective to remove
template materials and to activate the molecular sieve catalyst of this invention.
Such temperatures are generally in the range from about 400°C to about 1,000°C,
preferably from about 500°C to about 800°C, and most preferably from about
550°C to about 700°C.
V. Example of an Olefin Forming Reaction System
[0137] In one embodiment of the invention, the reaction system is an
olefin forming reaction system in which feedstock is converted into one or more
olefm(s). Typically, the feedstock contains one or more ?.liphatic-contairJ"p
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.
[0138] 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
memylethyl ether, alkyl halides such as methyl chloride and ethyl chloride, alkyl
ketones such as dimethyl ketone, formaldehydes, and various acids such as acetic
acid.
36
[0139] 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.
[0140] Non-limiting examples of oxygenates include methanol, ethanol, npropanol,
isopropanol, methyl ethyl ether, dimethyl ether, diethyl ether, diisopropyl
ether, formaldehyde, dimethyl carbonate, dimethyl ketone, acetic acid,
and mixtures thereof.
[0141] 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.
[0142] 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.
[0143] The catalyst composition of the invention is particularly useful in
the process that is generally referred to as the gas-to-olefms (GTO) process or,
alternatively, the methanol-to-olefins (MTO) process, hi 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 olefm(s), preferably and predominantly, ethylene and/or propylene.
[0144] 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
37
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.
[0145] 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 particular1-/
preferred.
[0146] 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.
[0147] The present process can be conducted over a wide range of
temperatures, such as in the range of from about 200°C to about 1000°C, for
example from about 250°C to about 800°C, including from about 250°C to about
750 °C, conveniently from about 300°C to about 650°C, typically from about
350°C to about 600°C and particularly from about 350°C to about 550°C.
38
[0148] 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.
[0149] 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'1 to about 5000 hr"1,
such as from about 2 hr"1 to about 3000 hr"1, for example from about 5 hr"1 to
about 1500 hr"1, and conveniently from about 10 hr"1 to about 1000 hr"1. In one
embodiment, the WHSV is greater than 20 hr"1 and, where feedstock contains
methanol and/or dimethyl ether, is in the range of from about 20 hr"1 to about 300
hr'1.
[0150] 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 Serial No.
09/708,753 filed November 8, 2000, which is herein incorporated by reference.
[0151] 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.
[0152] 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. Patent No. 4,076,796, U.S. Patent No. 6,287,522 (dual riser),
and Fluidization Engineering, D. Kunii and O. Levenspiel, Robert E. Krieger
Publishing Company, New York, New York 1977, which are all herein fully
incorporated by reference.
39
[0153] The preferred reactor types are riser reactors generally described in
Riser Reactor, Fluldization and Fluid-Particle Systems, pages 48 to 59, F.A. Zenz
and D.F. Othmo, Reinhold Publishing Corporation, New York, 1960, and U.S.
Patent No. 6,166,282 (fast-fluidized bed reactor), and U.S. Patent Application
Serial No. 09/564,613 filed May 4, 2000 (multiple riser reactor), which are all
herein fully incorporated by reference.
[0154] 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.
[0155] 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.
[0156] 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 99.9 weight percent, such as from about 1 weight percent to about 99 weight
percent, more typically from about 5 weight percent to about 95 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.
[0157] 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
40
embodiment, cyclone(s) are provided within the disengaging vessel to separate the
coked catalyst composition from the gaseous effluent containing one or more
olefm(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.
[0158] 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.
[0159] 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.
[0160] Non-limiting examples of suitable regeneration media include one
or more of oxygen, 63, 863, N2O, NO, NOa, NjOs, air, air diluted with nitrogen cr
carbon dioxide, oxygen and water (U.S. Patent No. 6,245,703), 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°C to about 1500°C, such as
from about 300°C to about 1000°C, for example from about 450°C to about
750°C, and conveniently from about 550°C to 700°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),
41
including from about 25 psia (172kPaa) to about 150 psia (1034 kPaa), and
conveniently from about 30 psia (207 kPaa) to about 60 psia (414 kPaa).
[0161] 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. The amount of oxygen in the regeneration flue gas
(i.e., gas which leaves the regenerator) 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. The
amount of oxygen in the gas used to regenerate the coked catalyst (i.e., fresh or
feed gas) is typically at least about 15 mole percent, preferably at least about 20
mole percent, and more preferably from about 20 mole percent to about 30 mole
percent, based on total amount of regeneration gas fed to the regenerator.
[0162] 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. Paterit No. 6.290,916 (controlling
moisture), which is herein fully incorporated by reference.
[0163] 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).
42
[0164] 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.
[0165] 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.
[0166] 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 olefm(s) from the gaseous effluent. Recovery systems generally
comprise one or more or a combination of various separation, tract! onati or and/or
distillation towers, columns, splitters, or trains, reaction systems such as
ethylbenzene manufacture (U.S. Patent No. 5,476,978) and other derivative
processes such as aldehydes, ketones and ester manufacture (U.S. Patent No.
5,675,041), 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.
[0167] 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,
43
membranes, ethylene (C2) splitter, propylene (C3) splitter and butene (C4)
splitter,
[0168] Various recovery systems useful for recovering olefin(s), such as
ethylene, propylene and/or butene, are described in U.S. Patent No. 5,960,643
(secondary rich ethylene stream), U.S. Patent Nos. 5,019,143, 5,452,581 and
5,082,481 (membrane separations), U.S. Patent 5,672,197 (pressure dependent
adsorbents), U.S. Patent No. 6,069,288 (hydrogen removal), U.S. Patent No.
5,904,880 (recovered methanol to hydrogen and carbon dioxide in one step), U.S.
Patent No. 5,927,063 (recovered methanol to gas turbine power plant), and U.S.
Patent No. 6,121,504 (direct product quench), U.S. Patent No. 6,121,503 (high
purity olefins without superfractionation), and U.S. Patent No. 6,293,998
(pressure swing adsorption), which are all herein fully incorporated by reference.
[0169] 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. Patent No.
6,271,428 (purification of a diolefin hydrocarbon stream), U.S. Patent No.
6,293,999 (separating propylene from propane), and U.S. Patent Application No.
09/689,363 filed October 20,2000 (purge stream using hydrating catalyst), which
are herein incorporated by reference.
[0170] 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 olefm(s)
produced particularly in a MTO process are passed through a purification system
that removes low levels of by-products or contaminants.
[01711 Non-limiting examples of contaminants and by-products include
generally polar compounds such as water, alcohols, carboxylic acids, ethers,
44
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.
[0172] Typically, in converting one or more oxygenates to olefin(s) having
2 or 3 carbon atoms, a minor amount hydrocarbons, particularly olefm(s), having
4 or more carbon atoms is also produced. The amount of €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 €4+ impurities to useful products.
[0173] Non-limiting examples of such reaction systems are described in
U.S. Patent No. 5,955,640 (converting a four carbon product into butene-1), U.S.
Patent No. 4,774,375 (isobutane and butene-2 oligomerized to an alkylate
gasoline), U.S. Patent No. 6,049,017 (dimerization of n-butylene), U.S. Patent
Nos. 4,287,369 and 5,763,678 (carbonylation or hydroformulation of higher
olefins with carbon dioxide and hydrogen making carbonyl compounds), U.S.
Patent No. 4,542,252 (multistage adiabatic process), U.S. Patent No. 5,634,354
(olefin-hydrogen recovery), and Cosyns, J. et al., Process for Upgrading C3, C4
and C5 Olefmic Streams, Pet. & Coal, Vol. 37, No. 4 (1995) (dimerizmg or
oligomerizing propylene, butylene and pentylene), which are all fully herein
incorporated by reference.
[0174] 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.
[0175] 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,
45
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°C to about 1200°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.
[0176] 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°C to about 450°C and a pressure in the range of from about 5
MPa to about 10 MPa.
[0177] 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 fracticnation, resulting
in a purified oxygenate containing stream, for example, commercial Grade A and
AA methanol.
[0178] 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. Nonlimiting
examples of this integrated process are described in EP-B-0 933 345,
which is herein fully incorporated by reference.
[0179] hi 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 Serial
46
No. 09/615,376 filed July 13, 2000, which is herein fully incorporated by
reference.)
[0180] 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.
[0181] 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 olefm(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 ethyl ene 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.
[0182] 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.
47
VI. Examples of Starting Up a Reaction System Having a Reactor Unit
and Regenerator Unit
A. Example 1
[0183] One example of starting up a system containing molecular sieve
catalyst that is susceptible to deactivation due to contact with water molecules is
described in accordance with FIG. 1, which is a flow diagram of a reaction
system, containing a reactor 102 and a regenerator 104. The flow diagram of FIG.
1 is particularly directed to a system for converting oxygenates to olefins,
although it is particularly relevant to any system which incorporates a reactor and
regenerator. According to the embodiment shown in FIG. 1, the regenerator 104
is heated by injecting hot air. Air is input to the regenerator 104 by sending the air
through a compressor 106, through a conduit 108, to a heater or a burner 110, and
into the regenerator 104 by way of a conduit 112. The regenerator 104 is heated
for 8 hours at 400°F (204°C) at which time refractory in the regenerator 104 will
be substantially dry.
[0184] While the regenerator 104 is being heated, the reactor 102 is also
heated by injecting superheated steam through a conduit 114 and into regenerator
102. The reactor 102 is heated for 8 hours at 400°F (204°C) at which time
refractory in the reactor 102 will be substantially dry. After the reactor 102 has
been heated for a time to substantially dry out the refractory materials, the reactor
102 is heated to a reactor temperature of about 800°F (427°C) by injecting
superheated steam through the conduit 114.
[0185] While the reactor 102 is heated, and after the regenerator 104 has
been healed for a time to substantially dry out the refractory materials, the
temperature of the heated air into the regenerator 104 is increased to reach a
regenerator bed temperature of about 800°F (427°C). Once this bed temperature is
reached, catalyst is added to the regenerator 104 by a conventional hopper and
conduit system through an upper portion of the regenerator 104 (conventional
hopper and conduit system not shown).
[0186] After sufficient catalyst is loaded into the regenerator 104 to form a
bed, the bed is further heated by injecting a hydrocarbon oil into the bed through a
48
conduit 116. The bed will be sufficiently hot to combust the oil, thereby further
increasing temperature of the catalyst.
[0187] Once a predetermined amount of catalyst is input into the
regenerator 104 and heated to between about 800°F (427°C) and about 1200T
(649°C), the catalyst is circulated to the reactor 102 through a conduit 118, and
back from the reactor 102 through a conduit 120. A lift gas such as air is also
injected through the conduit 120 to aid in circulation. Additional catalyst is then
added to the regenerator to complete the catalyst loading. The catalyst is added at
a rate to maintain the system above about 800°F (427°C).
[0188] Once the reaction system is sufficiently heated, injection of air into
the reactor 102 is stopped so that steam or other appropriate gas is used to
sufficiently purge the reactor 102 of oxygen prior to injection of feed. After
appropriate purge of oxygen from reactor 102, hydrocarbon feed is injected
through the conduit 114 to contact the circulating hot catalyst, and the reaction
process begins. Reaction product is separated from the circulating catalyst by way
of cyclone separators 122, with the reaction product exiting the reactor 102
through a conduit 124. A portion of the catalyst is removed from reactor 102 by
way of the conduit 120 and sent to the regenerator 104 for regeneration.
Combustion products are removed from the regenerator 104 by way of a conduit
126.
B. Example 2
[0189] Another example of starting up a reaction system containing
molecular sieve catalyst that is susceptible to deactivation due to contact with
water molecules is described in accordance with FIG. 2, which is a flow diagram
of a reaction system as shown in FIG. 1. According to FIG. 2, the heat up
procedure is the same as that in Example 1, except that relatively dry gas is used
to heat reactor 202 rather than steam. According to FIG. 2, a portion the air sent
through air compressor 206 is sent through a conduit 228 to dry out heater 230 to
heat the air to the appropriate temperatures as stated in Example 1. As a result of
increasing the temperature of the air, the air is at a low relative water pressure, and
is considered substantially dry. This dry air is sent to the reactor 202 by way of
conduits 232 and 234, and the start up procedure of Example 1 is followed.
49
C. Example 3
[0190] Another example of starting up a reaction system containing
molecular sieve catalyst that is susceptible to deactivation due to contact with
water molecules is described in accordance with FIG. 3, which is a flow diagram
of a reaction system as shown in FIG. 2. According to FIG. 3, the heat up
procedure is the same as that in Example 2, except that air or gas from another
source is sent to a separate compressor 336, before being heated and sent to
reactor 302. All other aspects of the start up procedure pertaining to FIG. 3 are
the same as in Example 2.
D. Example 4
[0191] Another example of starting up a reaction system containing
molecular sieve catalyst that is susceptible to deactivation due to contact with
water molecules is described in accordance with FIG. 4, which is a flow diagram
of a reaction system as shown in FIG. 1. According to FIG. 4, the heat up
procedure is the same as that in Example 1, except that gas (e.g., air) is used to
heat up reactor 402 rather than steam. The gas is sent to a product recovery unit
440 of the reaction system, heated and sent to reactor 402. The product recovery
system includes cooler or steam generator 442, collection or quench vessel 444,
and compressor 446. According to FIG. 4, the gas is sent to the compressor 446
passed through a conduit 448, and sent to the steam generator 442. In a reaction
operation such as a catalytic cracking system or an oxygenate to olefins system,
the steam generator 442 would typically be used to cool product from the reactor
402, and to produce steam.
[0192] As shown in FIG, 4, the steam generator 442 is also arranged so
that at start up the gas passing through the steam generator 442 is heated indirectly
using the steam as a heating medium. The heated gas then passes to the reactor
402 in similar manner as that shown in FIG. 2 and FIG. 3. An advantage of the
arrangement in FIG. 4 is that the gas can be circulated in a relatively dry form
through the reaction system, without having to use an additional dry out heater to
heat the gas.
[0193] 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
50
parameters within what is claimed, without departing from the spirit and scope of
the invention.















WE CLAIM:
1. A process of starting up a reaction system, the process comprising the steps of:
a) heating at least a portion of the reaction system to a temperature of at least water critical temperature;
b) loading a catalyst, the catalyst comprising activated metalloaluminophosphate molecular sieve, into a heated portion of the reaction system, wherein the catalyst loaded into the reaction system is maintained at a predetermined catalytic activity index of at least 0.7 while the sieve is in the reaction system, with the catalytic activity index being defined as CAI = exp (f(T) *f(PPwater)n * alpha * t)
wherein
t = time of contact of catalyst with water (hours)
T = temperature at contact (°C)
PPwater = Partial Pressure of water in contact gas (psia)
alpha = -0.071
n = 3.5
f(T) = exp(ea(l/(T + 273) - 1/(To+ 273)))
ea = -5500°K
To = 200°C
f(PPwater) = (26.2 * PPWater/Psat + 1-14) * 0.175, for T ≥ 180°C (453°K)
f(PPwater) = ((26.2 + 0.272 * (180 - T)) * PPwater/Psat + 1.14) * 0.175,
for 180°C (453°K) > T ≥ 150°C (433°K) Psat = Saturation pressure of water at T (psia);
c) heating the catalyst loaded into the reaction system to a temperatuire at least 100°C higher than when first loaded into the reaction system.; and
d) contacting the heated catalyst with feed in the reaction system.
2. The process as claimed in claim 1, wherein the reaction system is a dense bed reaction
system, fixed bed reaction system, fluidized bed reaction system, fast fluidized bed
reaction system, circulating fluidized bed reaction system, or riser reactor system.
3. The process as claimed in any of the preceding claims, wherein the reaction system comprises a reactor and regenerator.
4. The process as claimed in claim 3, wherein, in step a), the reactor and regenerator are heated up and, in step b), the catalyst is loaded in the heated reactor or regenerator.
5. The process as claimed in any of claims 3 or 4, wherein the catalyst is loaded into the regenerator, further heated in the regenerator, and circulated to the reactor prior to contacting with feed.
6. The process as claimed in any of claims 3 to 5, wherein the heated catalyst is circulated to the regenerator using a lift gas.
7. The process as claimed in claim 6, wherein the lift gas is selected from the group consisting of air, nitrogen, helium, flue gas, CO2, fuel gas, and any combination thereof.
8. The process as claimed in any of claims 3 to 7, wherein the reactor is a hot wall or cold wall reactor.
9. The process as claimed in claim 1, wherein the heated portion of the reaction system into which the activated metalloaluminophosphate molecular sieve is loaded is heated to a temperature of at least 150°C, preferably to a temperature of at least 200°C, more preferably to a temperature of at least 300°C, prior to catalyst loading.
10. The process as claimed in claim 1, wherein the predetermined catalytic activity index is preferably at least 0.8 or more preferably at least 0.9.
11. The process as claimed in claim 1, wherein the metalloaluminophosphate molecular sieve is selected from the group consisting of SAPO-5, SAPO-8, SAPO-11, SAPO-16, SAPO-17, SAP018, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37, SAPO-40, SAPO-41, SAPO-42, SAPO-44, SAPO-47, SAPO-56, A1PO-5, AIPO-11, A1PO-18, A1PO-31, A1PO-34, A1PO-36, A1PO-37, A1PO-46, metal containing molecular sieves thereof, and mixtures thereof.
12. The process as claimed in claim 1, wherein the feed is selected from the group consisting of kerosenes, naphthas, diesels, light or heavy gas oils, vacuum distillates or residue,
light cycle oils, heavy cycle oils, benzenes, xylenes, toluenes, naphthalenes, and alcohols.
13. The process as claimed in claim 1, wherein the catalyst loaded into the reaction system is heated to a temperature of at least 400°C.
14. The process as claimed in claim 1, wherein the catalyst loaded into the reaction system is heated by combusting hydrocarbon oil in the reaction system.
15. The process as claimed in claim 1, wherein the reaction system is selected from the group consisting of catalytic cracking reaction systems, transalkylation reaction systems, isomerization reaction systems, catalytic dewaxing systems, alkylation reaction systems, hydrocracking reaction systems, systems for converting paraffins to olefins, systems for converting paraffins to aromatics, systems for converting olefins to gasoline, systems for converting olefins to distillate, systems for converting olefins to lubes, systems for converting alcohols to olefins, disproportionation reaction systems, systems for converting aromatics to higher aromatics, systems for adsorbing aromatics, systems for converting oxygenates to olefins, systems for converting oxygenates to aromatics, systems for oligomerizing olefins, and systems for converting unsaturated hydrocarbons to aldehydes.
16. The process as claimed in claim 1, wherein the reaction system is selected from the group consisting of catalytic cracking reaction systems, systems for converting oxygenates to olefins and systems for converting oxygenates to aromatics.
17. The process as claimed in claim 1, wherein the activated metalloaluminophosphate molecular sieve is a silicoaluminophosphate having a Si/Al ratio of not greater than 0.5, preferably of not greater than 0.3, more preferably of not greater than 0.2, even more preferably of not greater than 0. 15, and most preferably of not greater than 0.1.

Documents:

335-DELNP-2006-Abstract-(11-03-2010).pdf

335-delnp-2006-abstract.pdf

335-DELNP-2006-Claims-(09-07-2010).pdf

335-DELNP-2006-Claims-(11-03-2010).pdf

335-delnp-2006-claims.pdf

335-delnp-2006-correspondence-1.pdf

335-DELNP-2006-Correspondence-Others-(09-04-2010).pdf

335-DELNP-2006-Correspondence-Others-(09-07-2010).pdf

335-DELNP-2006-Correspondence-Others-(11-03-2010).pdf

335-delnp-2006-correspondence-others.pdf

335-DELNP-2006-Description (Complete)-(11-03-2010).pdf

335-delnp-2006-description (complete).pdf

335-DELNP-2006-Drawings-(11-03-2010).pdf

335-delnp-2006-drawings.pdf

335-DELNP-2006-Form-1-(11-03-2010).pdf

335-delnp-2006-form-1.pdf

335-delnp-2006-form-18.pdf

335-delnp-2006-form-2.pdf

335-DELNP-2006-Form-3-(11-03-2010).pdf

335-delnp-2006-form-3.pdf

335-delnp-2006-form-5.pdf

335-DELNP-2006-GPA-(11-03-2010).pdf

335-delnp-2006-gpa.pdf

335-delnp-2006-pct-101.pdf

335-delnp-2006-pct-220.pdf

335-delnp-2006-pct-237.pdf

335-delnp-2006-pct-306.pdf


Patent Number 242037
Indian Patent Application Number 335/DELNP/2006
PG Journal Number 33/2010
Publication Date 13-Aug-2010
Grant Date 06-Aug-2010
Date of Filing 19-Jan-2006
Name of Patentee EXXONMOBIL CHEMICAL PATENTS INC
Applicant Address 5200 BAYWAY DRIVE, BAYTOWN, TEXAS 77520-5200, UNITED STATES OF AMERICA.
Inventors:
# Inventor's Name Inventor's Address
1 PETER N. LOEZOS 7171 BUFFALO SPEEDWAY, HOUSTON, TX 77025, USA.
2 JAMES H. BEECH, JR. 3103 WILLOW WOOD TRAIL, KINGWOOD, TX 77345, USA.
3 RICHARD E. WALTER 157 BLACK RIVER ROAD, LONG VALLEY, NJ 77345, USA.
4 SHUN C. FUNG 855 PAPEN ROAD, BRIDGEWATER, NJ 08807, USA.
5 MARCEL J. G. JANSSEN DOMEINSTRAAT 84, B-3010 KESSEL-LO, BELGIUM
6 KENNETH R. CLEM 7407 PINE GREEN LANE, HUMBLE, TX 77346, USA.
7 STEPHEN N. VAUGHN 1111 SOUTHERN HILLS ROAD, KINGWOOD, TX 77339, USA.
8 LUC M. MARTEN ROOSTSTRAAT 18, B-1860 BEISE, BELGIUM.
PCT International Classification Number C10G 49/24
PCT International Application Number PCT/US2004/020770
PCT International Filing date 2004-06-28
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10/641,718 2003-08-15 U.S.A.