Process for gas phase polymerization of olefins

A process for the gas phase polymerization of olefins. In this process a transition metal-containing solid catalyst component is introduced into a cylindrical section of a vertically disposed reactor in a first stream. A second stream, comprising an organometallic cocatalyst component is simultaneously separately introduced into the said cylindrical section of a vertically disposed reactor at a distance from the point of introduction of the first stream of no more than about 20% of the inside diameter of the tubular reactor.

BACKGROUND OF THE DISCLOSURE 
1. Field of the Invention 
The present invention is directed to a process and apparatus for the gas 
phase polymerization of olefins. More particularly, the present invention 
is directed to a process and apparatus for polymerizing at least one 
olefin monomer in the presence of a catalyst system whose components are 
separately introduced into a gas phase reactor in close proximity to each 
other. 
2. Background of the Prior Art 
Gas phase processes and apparatus for the polymerization of at least one 
olefin are well known in the art. Among recent processes and apparatus 
developed for this purpose are systems wherein the catalyst components 
that constitute the catalyst system utilized in the olefin polymerization 
are separately introduced into the polymerization reactor. 
More specifically, it is known in the art to separately introduce, into a 
tubular gas phase reactor, a solid catalyst component and a cocatalyst 
component. That is, a solid catalyst component, which includes at least 
one transition metal, is introduced into the polymerization reactor 
separately from the cocatalyst component, which typically is an 
organometallic compound of a metal of Group 1, 2 or 13 of the Periodic 
Table. The organometallic compound of the cocatalyst component is 
preferably a hydrocarbyl-containing compound which includes a metal of 
Group 1, 12 or 13. More preferably, the cocatalyst component is an 
alkyl-containing compound which includes at least one of the 
aforementioned metals. The organometallic compound, which acts as the 
cocatalyst component, may optionally include halogen or hydrogen atoms and 
thus be a halide or hydride compound. 
These processes and apparatus are specifically designed to provide 
processing improvements over earlier olefin gas phase polymerization 
processes and apparatus. None of these recently developed systems, 
however, have adequately addressed certain well known problems associated 
with such processes and apparatus. Specifically, although the 
aforementioned recent developments are designed to eliminate operability 
problems, such as problems associated with catalyst clumping, which 
adversely affects operability, i.e. large catalyst particles tend to plug 
polymerization reactor withdrawal system, such as outlet conduits and the 
like, these developments have not fully addressed the associated problems 
of producing polymers having the necessary physical properties to meet 
specific customer needs. 
The most pertinent examples of the prior art, which illustrates gas phase 
polymerization of olefins wherein the catalyst and the cocatalyst 
components are separately introduced into the polymerization reactor, 
include U.S. Pat. No. 2,846,426 to Larson et al. In this process an 
ethylene gas stream is introduced into liquid titanium tetrachloride. The 
thereupon vaporized titanium tetrachloride is, in turn, introduced into a 
polymerization reactor. At the same time, a second ethylene gas stream is 
introduced into liquid diisobutylaluminum hydride to form a second 
vaporous composition which is also fed, through a separate inlet, into the 
same polymerization reactor. A third ethylene gas stream is separately 
introduced into the reactor. This scheme permits not only gas phase 
polymerization of ethylene but, in addition, in-situ formation of the 
catalyst system which catalyzes this polymerization reaction. This 
processing scheme is alleged, in the '426 patent, to improve control of 
active catalyst concentration relative to the concentration of the 
polymerizable ethylene. 
U.S. Pat. No. 2,939,846 to Gordon et al. describes a process wherein two 
separate inert gas streams entrain the vapors of two catalyst components 
of a Ziegler catalyst system utilized in olefin polymerization reactions. 
One of the inert gas streams entrains a vapor of a reducing compound, i.e. 
an aluminum-containing compound. The other inert gas stream entrains a 
vapor of a salt of a metal of Groups IV to VI of the Periodic Table. A 
particularly preferred metal of Groups IV to VI, preferred in the '846 
patent, is titanium. Also, in a preferred embodiment of the invention of 
the '846 patent the olefin monomer is used as the entraining gas. The two 
separate gas streams are intermixed at a temperature at which the reducing 
compound and the salt of a metal of Groups IV to VI are vaporizable. The 
olefin monomer is thereupon passed through a point at which the two 
gaseous streams intermix to form the solid catalyst. In an alternate 
embodiment, the solid catalyst product is deposited in a polymerization 
reactor. 
U.S. Pat. No. 4,035,560 to Caumartin et al. is directed to a fluidized bed 
olefin polymerization process wherein a first catalyst component, 
comprising the solid product of reaction of a transition metal compound 
and an organomagnesium compound, which may or may not be supported on an 
inert carrier, is entrained by the upward flow of a gaseous mixture which 
contains hydrogen and one or more olefin monomers. The thus formed 
fluidized bed also includes a second catalyst component, an organometallic 
compound of a metal of Group II or III of the Periodic Table, disposed on 
an inert porous support separately introduced into the reactor. 
U.S. Pat. No. 4,302,566 to Karol et al. sets forth a continuous process for 
ethylene copolymer production employing a gas phase fluidized bed vertical 
tubular reactor. A catalyst system is provided by a so-called precursor 
composition which is the solid reaction product of magnesium chloride and 
titanium tetrachloride. This "precursor composition" is activated in one 
of two ways. In the first, the precursor composition is slurried in a 
solution of the activator compound, triethylaluminum. The thus coated 
solid particles are thereupon dried and introduced into a vertical 
disposed tubular reactor downstream of the point of introduction of the 
monomer or monomers. In addition, supported activator particles, formed by 
slurrying an inert support in a solution of triethylaluminum followed by 
the driving off of the solvent, is introduced into the reactor along with 
the activated precursor composition. 
In an alternative embodiment, the triethylaluminum may be introduced in the 
liquid state by merely introducing a liquid solution of triethylaluminum 
in an inert hydrocarbon at the same position in the reactor as is the 
activated precursor solid composition. This second activation embodiment 
is very similar to the first described activation process except that the 
solid precursor composition particles and the solid aluminum disposed on 
an inert support are premixed prior to their introduction together into 
the reactor. 
U.S. Pat. No. 4,665,143 to Ahluwalia et al. sets forth a process for 
polymerizing olefins in a vertical tubular reactor. An olefin monomer or 
monomers is introduced into a reactor in a gaseous stream at the upstream, 
bottom end of the reactor. A first catalyst component, the reaction 
product of a transition metal compound and a metal alkyl of a metal of 
Group IA, IIA or IIIB, disposed on an inert support, is introduced 
downstream of the point of introduction of the monomeric gas stream. A 
second catalyst component cocatalyst, an aluminum alkyl, is introduced 
with the olefin monomer into the reactor in an inert hydrocarbon liquid 
solution above and downstream of the introduction point of the first 
catalyst component. The distance between the introduction of the first and 
the second catalyst components is at least two mixing distances. A mixing 
distance is defined as the distance, measured from the injection point, 
where only an equilibrium concentration of the introduced substance is 
present. This mixing distance limitation is said in the '143 patent to 
insure against the formation of "hot spots," and to minimize "lump" 
formation. 
U.S. Pat. No. 4,921,919 to Lin et al. is directed to a process and 
apparatus for the polymerization of an olefin monomer, preferably 
propylene, in a vapor phase tubular horizontal reactor. A 
titanium-containing first catalyst component is introduced into the top 
side of the horizontal reactor adjacent to its upstream end. A second and 
a third catalyst component, i.e. a cocatalyst and a modifier, 
respectively, are also fed into the top side of the horizontal reactor 
vessel, downstream of the point of introduction of the first catalyst 
component. This downstream distance is at least 25% of the internal 
diameter of the tubular reactor. This minimum distance is needed to 
minimize formation of polymer lumps. 
The above described processes and apparatus of the most pertinent prior art 
references provide improvements in gas phase olefin polymerization 
operability. However, these processes and apparatus do not address the 
need in the art for olefin polymeric products having the desired 
crystallinity and strength properties required of high strength olefin 
polymers. Thus, there is still a need in the art for an improved gas phase 
olefin polymerization process and apparatus which provides not only 
improved operability but an olefin polymer product having improved 
physical properties. 
BRIEF SUMMARY OF THE INVENTION 
A new process and apparatus for the gas phase polymerization of an olefin 
has now been developed to produce an olefin polymer product having 
improved physical properties without sacrificing reactor operability. 
In accordance with the present invention, a process is provided for 
polymerizing olefins which comprises polymerizing at least one olefinic 
monomer under gas phase olefin polymerization conditions in the presence 
of a catalyst system that includes a transition metal-containing solid 
catalyst component and an organometallic compound of a metal of Group 1, 2 
or 13 of the Periodic Table of the Elements-containing cocatalyst 
component. The solid catalyst component is introduced into a tubular 
reactor in a first stream. A second stream, comprising at least one 
olefinic monomer and the cocatalyst component, is simultaneously 
introduced into the reactor wherein the first and second streams are 
separated by a linear distance of no more than about 20% of the inside 
diameter of the tubular reactor. 
In further accordance with the present invention, an apparatus for the gas 
phase polymerization of an olefin is provided. The apparatus comprises a 
tubular reactor provided with means for the gas phase polymerization of at 
least one olefin. Specifically, the reactor includes a first means for the 
introduction of a first stream of a transition metal-containing solid 
catalyst component and a second means for the introduction of a second 
stream of the olefin and a cocatalyst component, the cocatalyst component 
comprising an organometallic compound of a metal of Group 1, 2 or 13 of 
the Periodic Table of the Elements. The first and second means are 
separated by a length no greater than about 20% of the length of the 
inside diameter of the tubular reactor.

DETAILED DESCRIPTION 
The process and apparatus of the present invention involves polymerization 
of at least one olefin, under gas phase olefin polymerization conditions, 
employing a fluidized bed or a stirred bed, in a tubular reactor which may 
be vertically or horizontally disposed. Polymerization in either of these 
reactors is described hereinafter. 
The gas phase olefin polymerization process and apparatus of the present 
invention include a catalyst system comprising at least two catalyst 
components. In a preferred embodiment the catalyst system includes three 
catalyst components. These catalyst components are separately and 
simultaneously introduced into the polymerization reactor. Although 
processes and apparatus are known for the introduction of catalyst 
components, none of them utilize the novel introduction system employed in 
the process and apparatus of the present invention. 
In the present invention a solid catalyst component is introduced into the 
reactor in close proximity to the cocatalyst component. Moreover, in a 
preferred embodiment, where a third catalyst component, a promoter, is 
employed, the solid catalyst component is introduced into the reactor in 
close proximity to the cocatalyst and promoter components. Specifically, 
the solid catalyst component is introduced into a gas phase tubular 
reactor, whether disposed vertically or horizontally, at a distance from 
the cocatalyst component, and, in the preferred embodiment wherein a 
promoter is included, from the point of introduction of the cocatalyst and 
promoter catalyst components, no further apart than a linear distance 
equal to about 20% of the length of the inside diameter of the tubular 
reactor. Preferably, this length is no greater than 10% of the inside 
diameter of the reactor. More preferably, this distance does not exceed 5% 
of the length of the inside diameter. Most preferably, the solid catalyst 
is introduced into the reactor through a central tube which is surrounded 
by an annular tube. The annular tube provides the means of introduction of 
the cocatalyst and, if included, the promoter. Thus, in this most 
preferred embodiment, the catalyst components are introduced separately 
but in very close proximity to each other. 
This critical element of the process and apparatus of the present invention 
is illustrated in the drawings. A vertical tubular reactor 10 and a 
horizontal tubular reactor 100 are depicted in FIGS. 1 and 2, 
respectively. These depictions are, as stated above, generalized flow 
diagrams illustrating general principles involved in the gas phase 
polymerization of olefins of the present invention. Although many aspects 
of the process and apparatus are illustrated, certain non-critical 
aspects, such as a quenched liquid feature, which may or may not be 
included in the gas phase process and apparatus of the present invention, 
are not described herein. 
In the preferred embodiment wherein a vertical tubular reactor is employed, 
introduction of the catalyst components into tubular reactor 10 is 
provided by introduction means 6. Introduction means 6, in the preferred 
embodiment illustrated in FIGS. 1 and 3, includes a central tube 8 
surrounded by an annular tube 12. The solid catalyst component, to be 
discussed below, is introduced into reactor 10 through central tube 8 
while the annular tube 12 serves as a mean of ingress of the cocatalyst 
component and, in the preferred embodiment where a third catalyst 
component is utilized, the promotor component. 
In the preferred embodiment wherein a horizontal tubular reactor is 
utilized, a similar scheme is utilized for the introduction of the 
catalyst system which comprises at least two catalyst components. That is, 
an introduction means 106 is provided which includes a central tube 108 
and an annular tube 112 for introduction of the two or three catalyst 
components into horizontal reactor 100. 
It is emphasized that the present invention is not limited to the preferred 
embodiment wherein a central and an annular tube are utilized to provide 
means of introduction of the catalyst components of the olefin 
polymerization catalyst system. This preferred embodiment merely provides 
a convenient and economical method of introducing the catalyst components 
within the scope of the present invention. Thus, adjacent introductory 
means or any other arrangement to introduce the catalyst components into 
the reactor is within the contemplation of the present invention, with the 
proviso that the distance between the point of introduction of the solid 
catalyst component and the cocatalyst component is not further apart than 
a linear distance equal to about 20% of the inside diameter of the tubular 
reactor, whether disposed vertically or horizontally. Of course, an 
embodiment wherein this length is no more than about 10% of the inside 
diameter and an embodiment wherein this length is no longer than about 5% 
of the inside diameter are, respectively, preferred and more preferred. 
It is well known in the art that olefin polymerization catalyst systems 
usually include at least two components. The first catalyst component is 
usually a solid catalyst component which includes at least one transition 
metal therein. Although the solid catalyst component of the olefin 
polymerization catalyst system can include one or more transition metals, 
i.e. metals of Groups 4, 5, 6, 7, 8, 9 and 10 of the Periodic Table of the 
Elements, it is preferred that the transition metal include one or more 
metals of Groups 4, 5 and chromium. Of these, it is particularly preferred 
that the solid catalyst component include titanium. 
The present invention is, of course, not limited to the specific identity 
or means of preparation of the solid catalyst component, provided the 
solid catalyst component includes at least one transition metal. 
Additionally, solid catalyst components which are supported or unsupported 
are within the scope of the present invention. A catalyst support is an 
inert organic or inorganic species. Preferred examples of catalyst 
supports include inert inorganic oxides such as silica, alumina, magnesia, 
silica-alumina, zirconia and the like. Of these, silica is particularly 
preferred. 
The solid catalyst component can include other components well known in the 
art. For example, a second metal selected from the group consisting of 
metals of Groups 1, 2 and 13 of the Periodic Table may be included. Of 
these metals, magnesium and aluminum are preferred, with magnesium being 
particularly preferred. In addition, the solid catalyst component may 
include an electron donor compound. 
The specific composition of the solid catalyst component is usually 
dictated by the specific identity of the olefin or olefins to be 
polymerized and the desired properties of the product polyolefin. For 
example, in the preferred embodiment wherein propylene is polymerized to 
produce a crystalline polypropylene product, it is particularly preferred 
that the transition metal included in the solid catalyst component be 
titanium alone or in combination with other transition metals. In that 
preferred embodiment wherein propylene is polymerized it is similarly 
preferred that magnesium be included in the solid catalyst component. 
A particularly preferred class of solid catalyst components is disclosed in 
U.S. Pat. Nos. 4,950,631; 5,098,969; 5,143,883; 5,145,821; 5,221,650; 
5,232,998 and 5,275,991 which disclosures are incorporated herein by 
reference. These disclosures all describe a solid catalyst component 
supported on silica which incorporates therein titanium and magnesium 
metal species. 
The cocatalyst component of the olefin polymerization catalyst system of 
the present invention acts as an activator for the solid catalyst 
component. Preferred cocatalyst components within the scope of this 
invention include organometallic compounds where the metal is a member of 
Group 1, 2, 12 and 13 of the Periodic Table of the Elements. Even more 
preferably, the cocatalyst is an organometallic compound wherein the metal 
is a member of Group 2, 12 or 13. More preferably, the organometallic 
compound is an organic compound which includes one or more metals selected 
from the group consisting of aluminum, magnesium, zinc or boron. Of these, 
aluminum is particularly preferred. 
The organometallic compound constituting the catalyst component is 
preferably a hydrocarbyl-containing compound which includes a metal 
limited to those defined in the above paragraph. More preferably, the 
cocatalyst component is an alkyl-containing compound which includes at 
least one of the aforementioned metals. 
The above discussed organometallic compound, which acts as the cocatalyst 
component, may optionally include halogen or hydrogen atoms and thus be a 
halide or hydride compound. Thus, particularly preferred cocatalyst 
components are such aluminum compounds as triethylaluminum, 
triisobutylaluminum, ethylaluminum dichloride, diethylaluminum chloride, 
ethylaluminum sesquichloride, diisobutylaluminum hydride, mixtures thereof 
and the like. Of these, triethylaluminum is particularly preferred for use 
as the cocatalyst component. 
As stated above, in a preferred embodiment of the process and apparatus of 
the present invention the olefin polymerization catalyst system includes a 
third component, a promoter. Promoter compounds are usually organic 
electron donor compounds which include organic esters, organic acid 
anhydrides, organic acid esters, alcohols, ethers, aldehydes, ketones, 
silanes, amines, amine oxides, amides, thiols, phosphorus acid esters and 
phosphorus acid amides. Mixtures of two or more organic electron donors 
are also within the contemplation of this invention. 
Of the promoters within the contemplation of this invention, organic acids, 
organic acid esters and silanes are particularly preferred. Examples of 
preferred organic acids and organic acid esters are benzoic acid, 
halobenzoic acid, phthalic acid, isophthalic acid, terephthalic acid, 
methyl benzoate, ethyl benzoate, butyl benzoate, isobutyl benzoate, methyl 
bromobenzoate, ethyl chlorobenzoate and the like. 
Among the silanes preferred for use in the present invention are 
hydrocarbylhydrocarbyloxysilanes, hydrocarbylsilanes and 
hydrocarbyloxysilanes having the structural formula Si(OR.sup.1).sub.4-p 
(R.sup.2).sub.p, where R.sup.1 is the same or different and is 
hydrocarbyl; R.sup.2 is the same or different and is hydrocarbyl; and p is 
O or an integer of 1 to 4. It is particularly preferred that the 
hydrocarbyl radicals, i.e. R.sup.1 and R.sup.2, be alkyl groups and that p 
be an integer of 1 to 3. Thus, alkylalkoxysilanes are particularly 
preferred embodiments of promoters within the scope of the present 
invention. For example, silanes such as diisopropyldimethoxysilane, 
isobutyltrimethoxysilane, isobutylisopropyldimethoxysilane and the like 
are particularly preferred for use as the promotor component of the 
catalyst system of the process and apparatus of the present invention. 
The above discussion of the olefin polymerization catalyst system does not 
distinguish between so-called Ziegler-Natta olefin polymerization catalyst 
systems, well established in the art, and more recently developed 
metallocene olefin polymerization catalyst systems. Both systems utilize a 
solid catalyst component containing at least one transition metal, albeit 
in the case of metallocene solid catalyst components the transition metal 
of choice may be zirconium, or, less preferably, hafnium, as well as 
titanium. Both systems additionally provide an organometallic compound 
albeit, in the case of metallocene catalyst systems, the organometallic 
compound usually includes oxygen. For example, aluminoxanes are preferably 
employed. 
Metallocene solid catalyst components are transition metal-containing 
compounds which include at least one substituted or unsubstituted 
cyclopentadienyl ring bonded to the transition metal atom. Metallocene 
compounds have been the subject of many publications and their identity is 
well known to those skilled in the art. 
Turning to the introduction of the reactant mixture into either vertical 
disposed reactor having a cylindrical section 10 or horizontal tubular 
reactor 100 the solid catalyst component is introduced through conduit 2 
or 102, respectively. Conduit 2 or 102 is in communication with an inlet 
means, which in the particularly preferred embodiment of the present 
invention is illustrated by reactor inlet means 6 or 106. Specifically, 
conduit 2 or 102 is in communication with central tube 8 or 108 of inlet 
means 6 or 106. Similarly, the cocatalyst component and, in the preferred 
embodiment wherein a promoter is included, the promoter catalyst 
component, are introduced into reactor 10 or 100 through conduit 4 or 104 
which is in communication with annular tube 12 or 112 of inlet means 6 or 
106. 
Other components are also introduced into reactors 10 or 100 through 
conduit 4 or 104. In the preferred embodiment wherein a promotor catalyst 
component is included in the olefin polymerization catalyst system, it is 
introduced into conduit 4 or 104 through conduit 14 or 114, respectively, 
from a source denoted in the drawings as 34 or 134, respectively. The 
promotor, in one preferred embodiment, is introduced into the reactor 
separately from the cocatalyst. In another preferred embodiment, the 
cocatalyst and the promotor compounds are premixed and are introduced into 
the reactor as a single composition. That is, source 34 or 134 may 
represent two separate components or a single composition. Independent of 
whether two separate compounds or a composition of two compounds are 
supplied through conduit 14 or 114 into conduit 4 or 104, it is preferred 
that the cocatalyst and promotor compounds, separately or together as a 
composition, be introduced in a solution of an inert hydrocarbon solvent. 
A second introductory conduit is depicted at 16 or 116. Conduit 16 or 116 
provides means for ingress of one or more olefin monomers into conduit 4 
or 104 and thereupon into reactor 10 or 100. That is, the olefin monomer 
or monomers to be polymerized, provided by source 36 or 136, can be 
introduced through conduit 16 or 116. 
Although olefin monomer can be introduced into the reactor through conduit 
16 or 116, it is not feasible to introduce the large volume of fresh feed 
required in commercial continuous operation through this relatively small 
tube. Thus, a conduit 35 or 135 provides communication for alternate 
introduction of fresh monomer feed. 
The olefin monomer or monomers which may be introduced into conduit 35 or 
135 can be fed into the tubular polymerization reactor independently or 
can be combined with recycle monomeric feed discussed below. The 
embodiment wherein all or a portion of the monomeric feed is introduced 
along with a recycle stream is illustrated in the depiction of the 
vertical reactor of FIG. 1. Therein, conduit 35 is in downstream 
communication with conduit 20 wherein the olefin is introduced into the 
reactor along with recycle olefin monomer through conduit 5. 
The preferred embodiment wherein all or some of the fresh olefin monomeric 
feed is independently introduced into the reactor other than through 
conduit 16 or 116 is depicted in the horizontal reactor of FIG. 2. 
Therein, conduit 135 communicates directly between conduit 116 at its 
upstream end and the interior of the reactor 100 at its downstream end. 
This arrangement provides independent introduction of fresh olefin monomer 
or monomers at the upstream end of the reactor. It should be appreciated 
that although FIG. 2 depicts a single point of introduction, a manifold 
may be utilized to insure introduction of the monomer over a wide length 
of the upstream end of reactor 100. 
Preferably, the olefin or olefin monomers are .alpha.-olefins. More 
preferably, the .alpha.-olefin monomer or monomers contain 2 to about 12 
carbon atoms. Still more preferably, one or more .alpha.-olefin monomers 
containing 2 to about 8 carbon atoms are provided. Even more preferably, 
the olefin monomer is ethylene or propylene alone, in combination with 
each other or in combination with one or more higher .alpha.-olefins 
containing 4 to 8 carbon atoms. 
Conduit 18 or 118 illustrates the means of communication of a source of 
hydrogen gas, depicted in the drawings at 38 or 138. Conduit 18 or 118 is 
in communication with conduit 4 or 104 as well as conduit 37 or 137. As 
those skilled in the art are aware, hydrogen gas acts as a chain-transfer 
agent to adjust the molecular weight of the polymer product. Hydrogen gas 
also serves to enhance reactivity of low reactive monomers in embodiments 
wherein copolymers are polymerized. Of significance, the greater the 
concentration of hydrogen employed in the polymerization reaction, the 
lower will be the molecular weight of the polymer product. For these 
reasons, it is preferred to include hydrogen in the gas phase olefin 
polymerization process and apparatus of this invention. The exact 
concentration of hydrogen gas, as measured by % volume, based on the total 
volume of the olefin and hydrogen gases introduced into the reactor, is a 
function of the desired polymer molecular weight. 
It is emphasized, however, that the inclusion of hydrogen gas, in the gas 
phase olefin polymerization process and apparatus of this invention, is 
not essential and thus may be omitted without disturbing the process and 
apparatus constituting the present invention. 
As in the case of the olefin monomer or monomers, the introduction point of 
the hydrogen gas is optional. That is, it may be introduced into the 
tubular reactor though conduit 4 or 104 in communication with the 
downstream end of conduit 18 or 118 along with the cocatalyst and, if 
present, the promoter. Alternatively, the hydrogen gas can be introduced 
separately into the reactor by being conducted through conduit 37 or 137, 
wherein it may be introduced with the olefin monomer or monomers as 
discussed in the description of the introduction of the olefin monomer, or 
it can be split and partially introduced along with the cocatalyst and 
partially independently introduced with the monomer through a separate 
ingress means or through the recycle conduit. 
It should be emphasized that in the case where the hydrogen gas is 
independently introduced into the reactor with olefin monomer it is 
preferred that conduit 137 merge into conduit 135, which conveys the 
monomer resulting in a combined stream of monomer and hydrogen gas fed 
into the reactor through conduit 135. 
The gas phase olefin polymerization process and apparatus of this 
invention, depicted in FIGS. 1 and 2, includes a commonly employed recycle 
system. As stated above, the olefin or olefins is introduced into the 
vertical and horizontal reactor, respectively through annular orifice 12 
or 112 which is in upstream communication with conduit 4 or 104. That 
stream includes, in addition to the olefin monomer or monomers, a 
cocatalyst, both a cocatalyst and a promoter or a composition comprising a 
premixed cocatalyst and promoter. The aforementioned stream is fed into 
conduit 4 or 104 through feeding conduit 16 or 116. In addition, the 
stream flowing in conduit 4 or 104 may include, in a preferred embodiment, 
hydrogen gas. The hydrogen gas, provided at 38 or 138, is supplied to 
conduit 4 or 104 by conduit 18 or 118. 
The solid catalyst component is stored in an enclosed storage vessel 9 or 
109 in communication with conduit 2 or 102, by conduit 19 or 119, which, 
as indicated earlier, is in downstream communication with central tube 8 
or 108. Fluidization of the solid catalyst component is provided by a 
stream of an inert gas, preferably nitrogen, which is provided at a rate 
such that the desired mass rate of fresh catalyst component is provided 
into the vertical or horizontal tubular reactor 10 or 100. 
The monomer or monomers, the catalyst components and the modifying agent, 
if present, enter reactor 10 or 100 and move toward the downstream end of 
the reactor as depicted in the drawing by arrow 40 or 140. This two-phase 
solid-gas flow is primarily provided by the recycle gas stream emanating 
from the upstream end of the reactor as discussed below. 
Gas flow in reactor 10 or 100 moves downstream until it exits the reactor 
at its downstream end through conduit 20 or 120. That only gas, and not 
solid particles, leaves reactor 10 or 100 is aided by the optional 
inclusion of a gas velocity reduction zone. Such a zone is illustrated in 
vertical reactor 10 by reduction zone 42. This zone is characterized by a 
wider diameter than the remainder of the tubular reactor. This wider 
diameter reduces gas stream velocity. As gas stream momentum decreases, 
the higher density solid particles fall downward in the upstream 
direction. 
The unreacted gas stream exiting the downstream end of reactor 10 or 100 is 
conveyed through recycle conduit 20 or 120. A purge line 30 or 130, in 
communication with conduit 20 or 120, is provided to sample the gas stream 
to determine its constituency. Purge line 30 or 130 also serves to 
eliminate inert gases, such as vaporized hydrocarbon solvents, which would 
otherwise build up in the system. These gases may be flared or repurified 
for reuse. 
The gas in conduit 20 or 120 may be filtered by filter 22 or 122 to remove 
small particles that are entrained by the gas stream exiting the 
downstream end of the reactor. Although very little solid entrainment is 
encountered, even a small concentration of solids may adversely affect the 
operation of the heat exchanger and compression means disposed further 
downstream in conduit 20 or 120. 
The gas stream, after optional filtering, is cooled in a heat exchanger 24 
or 124. The gas stream flowing in conduit 20 or 120 is at elevated 
temperature due to the heat generated in the polymerization reaction. By 
removing this heat of polymerization reaction, the gas stream in conduit 
20 or 120, upon recycle into reactor 10 or 100, does not increase the 
temperature therein. 
The cooled gas stream in conduit 20 or 120 is then compressed by compressor 
32 or 132 and recycled, by means of conduit 5 or 105, into the upstream 
end of reactor 10 or 100. The recycle gas stream is substantially all 
unreacted olefin monomer. The gas stream enters the upstream end of 
reactor 20 or 120 and moves downstream. In the case of a vertical disposed 
reactor, the gas stream passes through a distribution plate 26. 
Distribution plate 26, may be a screen, a slotted plate, a perforated 
plate, a bubble cap plate or the like. Plate 26 permits gaseous flow 
therethrough but does not permit flow of solid particles. Thus, catalyst 
particles and solid polymer product are prevented from plugging the 
upstream entrance of the recycle stream by stopping the upstream flow of 
solids on the top, downstream surface of plate 26. 
More importantly, the distribution plate 26 prevents formation of a 
quiescent mass during polymerization. Such a condition results in the 
formation of a solid block due to the active condition of the hot polymer 
particles in contact with active catalyst particles. The recycle gas 
stream entering the reactor through conduit 5 is diffused through 
distribution plate 26 to keep the particles above the plate 26 fluidized. 
It should, of course, be appreciated, on the other hand, that the 
distribution plate 26, serves as a base for the formation of a quiescent 
bed of polymer and catalyst when the reactor 10 is not in operation. 
As discussed above, virgin monomer, the catalyst system and hydrogen, if 
present, are introduced into the reactor 10 or 100 downstream of the 
upstream end where the recycle gas stream is introduced. The point of 
introduction of inlet means 6 or 106 is indeed significantly downstream of 
the point of introduction of the recycle stream. This arrangement insures 
that polymerization occurs downstream of the distribution plate 26, thus 
preventing recycle gas entry plugging. Moreover, this downstream point of 
introduction aids in preventing the formation of localized "hot spots" 
caused by localized concentration of catalyst. That is, introduction of 
catalyst components into the fluidized portion of the reactor insures good 
distribution of those components. The above description infers that most 
of the monomeric reactant is provided by the recycle stream introduced 
through conduit 5 or 105. 
The olefin polymeric product is removed by product take off conduit 28 or 
128. In the preferred embodiment wherein the tubular reactor is disposed 
vertically, i.e. reactor 10, the take off conduit is preferably situated 
at the surface of the distribution plate. In the preferred embodiment 
wherein a horizontally disposed reactor, i.e. reactor 100, is employed the 
take off conduit 128 is preferably placed at its bottom at the downstream 
end. 
The reactor 10 or 100, and thus the polymerization reaction, is maintained 
at a temperature in the range of from about 0.degree. C. to about 
120.degree. C. and at a pressure of about 20 psi to about 600 psi. 
Preferably, the thermodynamic conditions in the polymerization reactor 10 
or 100 include a temperature in the range of between about 20.degree. C. 
and about 100.degree. C. and a pressure in the range of between about 100 
psi and about 500 psi. More preferably, the thermodynamic conditions in 
the reactor 10 or 100 is a temperature of between about 50.degree. C. and 
about 90.degree. C. and a pressure of about 200 psi and about 450 psi. 
The rate of downstream gas velocity in reactor 10 or 100, in order to 
maintain the desired fluidization bed polymerization conditions, is in the 
range of between about 1.0 ft/sec and about 3.0 ft/sec. More preferably, 
the fluidized bed is maintained at a velocity of between about 1.5 ft/sec 
and about 2.5 ft/sec. 
The following examples are given to illustrate the scope of the present 
invention. Because these examples are given for illustrative purposes 
only, the invention should not be deemed limited thereto. 
EXAMPLE 1 
Polymerization of Propylene in a Tubular Vertical Reactor Using a Catalyst 
System Where the Solid Catalyst Components and Promotor are Introduced in 
Close Proximity 
A supported catalyst component was prepared in accordance with the teaching 
of U.S. Pat. No. 4,950,631, which teaching is incorporated herein by 
reference. Thus, the solid catalyst component comprised a catalytic agent 
which included titanium and magnesium disposed on a silica support. 
This solid catalyst component was introduced into a vertical tubular 
reactor of the type depicted in FIG. 1. The solid component was introduced 
through a central tube, as depicted at 8, having a diameter of 1/4 inch, 
of an introductory means of the type depicted at 6. The solid catalyst 
component was introduced at a rate of 9.6 gms/hr entrained by a stream of 
nitrogen gas. This rate was selected to insure that about 100 lb/hr of 
polymeric product was produced. The central tube 8 was disposed 2 feet 
above the distribution plate, depicted at 26. The vertical reactor itself 
had an inside diameter, in the fluidized bed portion wherein 
polymerization occurs, i.e. below the reduced velocity section 42, of 19 
inches and was 12 ft high. 
Introductory means 6 included an annular tube of the type illustrated in 
FIGS. 1 and 3 by tube 12. Propylene, hydrogen gas, triethylaluminum (TEAL) 
and diisopropyldimethoxysilane (DIPS) were introduced into a reactor of 
the type illustrated at 10 through annular tube 12. 
The vertical reactor 10 was maintained at a temperature of 180.degree. F. 
(82.degree. C.) and a pressure of 400 psig. The recycle stream was 
maintained at a rate sufficient to provide a fluidized bed linear velocity 
of 1.5 ft/sec wherein the gas stream entering through conduit 5, as 
analyzed at take off line 30, was 80 mole % propylene and 0.65 mole % 
hydrogen, the remainder being nitrogen. The catalyst components were 
introduced into reactor 10 such that the molar ratio of Al:Si:Ti of the 
catalyst system was 30:8:1. The polypropylene was taken off through line 
28. The polymerization reaction was continuously run for a period of 
approximately 2.1 hours. 
The above conditions were designed to not only provide about 100 lbs/hr of 
the polypropylene product but also to produce a product which had a degree 
of polymerization such that its melt flow rate was about 18. It is 
emphasized that no polymer agglomeration was noticed using the duration of 
the polymerization run. 
The polypropylene product was analyzed and the results of this analysis as 
well as the operating conditions of this example are summarized in Table 
1. 
EXAMPLES 2-4 
Propylene Polymerization Utilizing Higher Concentrations of Aluminum 
Example 1 was identically reproduced in Examples 2-4 but for the increase 
in the concentration of the TEAL feed into the reactor and the 
corresponding decrease in the hydrogen gas concentration. These changes 
canceled each other out to the extent that the nominal melt flow rate of 
the polypropylene product remained at about 18. 
In Example 2, this increased TEAL fed rate resulted in a Al:Si:Ti molar 
ratio of 40:8:1. In Example 3 this catalyst system molar ratio was further 
increased to 80:8:1 and in Example 4 the Al:Si:Ti molar ratio was further 
elevated to 120:8:1. It is emphasized that Examples 2-4 were otherwise 
identical with Example 1. Thus, the only distinction among Examples 1 to 4 
was the increased concentration of TEAL and decreased concentration of 
hydrogen gas introduced into the annular tube. 
The results of these examples are included in Table 1. It is again noted 
that no polymer agglomeration was observed. 
COMATIVE EXAMPLES 1-4 
Preparation of Propylene in Traditional Gas Phase Reactor 
Examples 1-4 were identically reproduced in all regards at Comparative 
Examples 1-4, respectively but for the point of introduction of the 
cocatalyst, TEAL and the promoter, DIPS. Whereas TEAL and DIPS were 
introduced into the reactor through annular orifice 12 in Examples 1-4, in 
Comparative Examples 1-4 TEAL and DIPS were introduced through a conduit 
in communication with conduit 5, in accordance with prior art cyclic gas 
concepts. 
The results of these runs are included in Table 1. 
TABLE 1 
______________________________________ 
Example Al:Si:Ti Molar 
DIPS Feed Flexural 
No Ratio Location Modulus.sup.1 
% HI 
______________________________________ 
1 30:8:1 Annular 221,900 
97.2 
CE1 30:8:1 Cycle Gas 177,500 
92.4 
2 40:8:1 Annular 218,400 
96.9 
CE2 40:8:1 Cycle Gas 180,500 
92.6 
3 80:8:1 Annular 162,700 
90.5 
CE3 80:8:1 Cycle Gas 172,000 
91.3 
4 120:8:1 Annular 159,500 
89.7 
CE4 120:8:1 Cycle Gas 165,000 
-- 
______________________________________ 
.sup.1 As determined by ASTM Test Procedure D790. 
DISCUSSION OF RESULTS OF TABLE 1 
The benefits of the present invention are defined in the data included in 
Table 1. Attention is particularly directed to Examples 1 and 2 which were 
run at the commercially important catalyst system molar ratios of Al:Si:Ti 
of 30:8:1 and 40:8:1. These runs, when compared to Comparative Examples 1 
and 2, were identical but for the addition of the cocatalyst and promoter 
through an annular tube in Examples 1 and 2 and the introduction of the 
cocatalyst and promoter through recycle inlet 5 in Comparative Examples 1 
and 2. 
Since all four runs utilized central tube 8 to introduce the solid catalyst 
component, Examples 1 and 2 illustrated the invention insofar as the 
linear distance between the solid catalyst component stream flowing 
through central tube 8 and the cocatalyst and promoter flowing through 
annular tube 12 is less than 5% of the diameter of the reactor. On the 
other hand, Comparative Examples 1 and 2 demonstrate the prior art cycle 
gas process wherein the linear distance between central tube 5, the entry 
point of the solid catalyst component, and conduit 5 is far in excess of 
20% of the reactor diameter. 
In all four runs, no polymer agglomeration was noticed. Thus, a perceived 
problem associated with close introduction of catalyst components is 
rebutted. Moreover, the product improvement of Examples 1 and 2, compared 
to Comparative Examples 1 and 2, in terms of significantly improved 
flexural modulus establishes the advance in the art of the present 
invention. It should also be appreciated that % heptane insolubility, a 
measure of the crystallinity of the product polypropylene, is appreciably 
increased when produced in accordance to this invention. Those skilled in 
the art are aware that flexural modulus is an established funtion of 
polymer crystallinity. 
It is conceded that at higher aluminum to titanium molar ratios, this trend 
was reversed. However, as indicated by the data in Table 1, commercial 
operation of gas phase reactors utilizes lower molar ratios of aluminum to 
titanium insofar as these lower ratios produce higher flexural modulus, 
independent of the location of the introduction of the catalyst components 
of the catalyst system. Indeed, a comparison between Comparative Example 2 
and Comparative Example 3 illustrate this point. In Comparative Example 2, 
utilizing an aluminum to titanium molar ratio of 40:1, the flexural 
modulus was 180,500 psi. At the higher aluminum to titanium molar ratio of 
80:1, this flexural modulus was reduced to 172,000 psi. Thus, commercial 
operation of a gas phase propylene polymerization process and apparatus 
utilizes a catalyst system, independent of the method of its introduction 
in which relative low aluminum to titanium molar ratios are employed. At 
the commercially significant aluminum to titanium molar ratios, the 
significant improvement of utilizing a catalyst system wherein the 
catalyst components are introduced in closer proximity to each other than 
in the prior art produces significantly improved polymers. 
The above preferred embodiments and examples are given to illustrate the 
scope and spirit of the present invention. These embodiments and examples 
will make apparent, to those skilled in the art, other embodiments and 
examples. These other embodiments and examples are within the 
contemplation of the present invention. Therefore, the present invention 
should be limited only by the appended claims.