JP3295640B2 - Improved gas fluidized bed polymerization process - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention Field of the Invention relates to an improved gas fluidized bed polymerization how. The term `` gas fluidized bed polymerization '' as used herein
Care, comprising a layer of polymer particles, the monomer that layer and
By passing the body flow, additively the layer with Te element
With or without mechanical agitation, cool, fluidize,
This refers to polymerization performed with stirring.

[0002]

BACKGROUND OF THE INVENTION Gas fluidized bed polymerization plants use a continuous system. Some of the system, heating the Re circulating gas stream by the heat of polymerization in the reactor. A cooling system outside the reactor removes the heat in other parts of the system. As well as additional monomers substituted for consumed monomer, continuously or intermittently adding the catalyst. The polymer particles are removed for finishing.

[0003] Large plants are expensive and highly productive. Downtime is expensive. The risks associated with experiments in such plants are high. Therefore, from the point of view of cost and risk, it is difficult to study experimentally design及beauty operations limit boundaries.

[0004] The present invention is to determine the stable operation region that put the gas fluidized bed polymerization, selects a desired work conditions have you the optimum design and predetermined plant design of the plant
It was possible I, provides a gas fluidized bed polymerization how to provide maximum reactor productivity.

[0005] gas fluidized bed reactor, the optimum Te manufacture smell <br/> of, is controlled to provide a melt index and density of Nozomu Tokoro the polymer. Great care is generally taken to avoid conditions that can result in the formation of chunks or sheets or, in the worst case, an unstable fluidized bed that collapses or that can fuse the polymer particles. That is, performs control of the fluidized bed, should reduce the shank forming and sheet forming, and must avoid collapse of the layers, or if allowed stop the operation of either or reactor terminate the reaction
You need to avoid things that are not . This is an industrial scale reactors are designed to be fully operated in the stable operation region has been demonstrated, and carefully control
In limited been state-like, which is why the reactor Ru Tei used.

[0006] Even in the conventional stable operation region, the new and TSS Daso viewed improved operating conditions, control Tsu complicated der further added to the difficulty and uncertain of experiments
Was .

There are target values, determined by the polymer and catalyst, for operating temperature, comonomer to monomer ratio and hydrogen to monomer ratio. The reactor and cooling system, Ru Tei contained in a pressure vessel. In particular, (1) the pressure at the top, (2) the pressure difference at different heights in the bed, (3) the temperature upstream of the fluidized bed, (4) the temperature in the fluidized bed and the temperature downstream of the fluidized bed, and (5) by measuring the composition and (6) gas flow rate of the gas, their contents without interfering unduly flow is Ru monitored. These measurements <br/> is particularly catalyst addition is used to control the speed of the monomer partial pressure and recycle gas. Removal of the polymer, in certain cases, settling bulk density which depends on the plant design (settle
d bulk density) (constrained by a non-fluidized state) or fluidized bulk density (fluidizedbulk density), therefore this
These two must be watched as well as the amount of ash in the polymer. The plant is a closed system. In operation, changes in the process of one or more measurements necessarily result in changes elsewhere . In plant design, capacity optimization depends on most limiting factors in the overall design.

[0008] There is no generally accepted opinion as to what results in chunking or sheeting. Maybe,
The fusion of the polymer particles due to insufficient heat transfer caused by improper flow in the fluidized bed is obviously somewhat involved. However, until now, individual settings and
And measurements are not heading clear correlation between occurrence of chunks forming and sheet forming. Therefore, conventionally, the whole measurement and control have been used in order Me Todo to the reaction system Oite known safe operating area to a predetermined plant design.

[0009] It is desirable to provide a maximum reactor gas fluidized bed polymerization how to give productivity.

[0010] The Jenkins (Jenkins) U.S. Patent No. 4,588,790 by et al. And No. 4,543,399, the general control and, difficulty and complexity of the attempt to extend the stable operation area in order to optimize the space time yield is shown Have been.

[0011] Jenkins et al., Condensable fluid (condensed
The recycle gas as fluid) evaporates inside the reactor
It is cooled and added to the reactor at a temperature below the dew point. When the cooling heat medium is at the predetermined temperature , the cooling capacity of the recirculated gas may be further increased for a while. One option described is to add a non-polymeric substance (isopentane) that increases the dew point. Due to the greater cooling, more heat is removed and higher space-time yields are stated to be possible. Jenkins et al. Disclose a condensed liquid in an amount of up to 20% by weight, preferably 2 to 12% by weight, in the recycle gas .
Recommended for use . Obstacles that may have been disclosed include:
Generation of "mud" (U.S. Pat. No. 4,588,790, column 5, 35
-39 line), maintaining a sufficiently high recycle gas speed (column 6, 12-20 rows) and, to avoid accumulation of liquid in the distributor plate (column 6, 28-32
Line) is included. Only in the case of directly adding the condensed material layer (8 column, lines 16-20), greater than 20% condensed matter can be used.

[0012] The viewpoint et specially important in this invention, in the recycle stream is cooled, respectively 65.9,34.0 and 53.5 ° C.
Using 14.2 , 10.5 and 12.9 mol% of isopentane, with condensate amounts of 11.5 , 10.5 and 14.3% by weight and 7.0, 1
Ru Tei given the space-time yield of 0.7 and ^{6.2 (lb / hr · ft 3} ),
Examples 6, 7 and 10a.

[0013] Jenkins et al., And either the upper limit of the amount of non-polymerizable or polymerizable condensable materials where present, condensed
It does not describe how to optimize the space-time yield using the embodiment . Jenkins et al., Not not describe the special role for fluidized bulk density, also indicated for the composition of the recycle stream may help to determine your Keru stable operation region to a higher space-time yield Not.

[0014]

[0005] Accordingly, features have danger is reduced of failure, find criteria for implementing safe <br/> all way to indicate a reactor productivity have high simultaneously, and / or,
To avoid constraints in the overall plant capacity due to the reactor productivity, determine the stable operation area and plant design for gas fluidized bed polymerization how the row under such conditions
A fluidized bed polymerization method that gives the highest possible reactor productivity
Be provided is an object of the present invention.

Thus, the present invention provides an improved gas fluidized bed polymerization.
An object of the present invention is to provide an METHODS.

[0016]

Means for Solving the Problems The present invention comprises a gas stream containing monomer, in the presence of a catalyst under reactive conditions, passed through a fluidized bed reactor, the polymerization product, the unreacted monomer gases Producing a stream, its unreacted monomer gas
Compressing the stream comprising, by <br/> a mixture between the gas phase and the liquid phase is cooled, the mixture was mixed with the feed components, obtained
Vapor / liquid phase mixture including that returned to the reactor, the gas was
A fluidized bed polymerization process, the weight of the liquid phase, the total weight 15 wt.% Based on the mixture which passed back <br/> the reactor, good
Preferably, the unreacted monomer gas is added so as to exceed 20% by weight.
Cooling the containing stream , and containing the monomer.
And the ratio of the fluidized bulk density to the settled bulk density in the reactor exceeds 17.8 / 30.2 (0.20.59).
Properly will have a 18.1 / 30.2 (≒ 0.60) ultra city of so that composition
Comprising to the so that, provided a gas fluidized bed polymerization process
I do.

[0017]

DETAILED DESCRIPTION OF THE INVENTION In order to optimize the operating conditions and plant design underlying the present invention, the fluidized bulk density for a given class of polymer and / or catalyst composition is considered.
d bulk density) (FBD) variation can be used. The Jenkins et al., Percentage of condensed liquid body, to define the space-time yield to be upper and achieving the amount of cooling can be achieved
While that is a useful, in the present invention, greater amounts of condensate body than disclosed by Jenkins, et al. (Cond
ensed liquid) even when the involved uses a FBD to determine the safe operating area.

Accordingly, Japanese Patent Application No. 6-5, which is the basis of the present invention.
Of No. 01,456 invention, a gas stream having including a motor Noma over
And passed through a dynamic bed reactor flow in the presence of a catalyst in reactivity conditions, the polymerization product, a stream comprising unreacted monomer gases
Resulting that, be a mixture of compressed flow cooling the vapor phase and the liquid phase containing unreacted monomer gases, the mixture <br/> mixed with feed components, resulting vapor / liquid Phase mixture
For gas flow Doso polymerization how that includes returning the reactor
The method for determining stable operating conditions, wherein (a)
Monomer alter the composition of the gas stream containing, or changes in fluidized bulk density of the fluidized bulk density in the <br/> reactor
Observe the change in the parameter that indicates the change (this
Cormorants Do changes caused by changes in the composition), (b) Engineering
From the results observed in step (a), it was found that the fluidized bulk density did not decrease.
The fluidized bulk density or parameter value when reversible
And (c) a gas containing the monomer.
Range of body flow composition (within that range determined in step (b)
The polymerization can take place in an area that does not exceed the
Including that you determine that), related to a method of determining stable operating conditions.

In the present specification, the fluidized bulk density is sometimes abbreviated as FBD and the settled bulk density is abbreviated as SBD. As a general rule, low down to less than 0.59 in the ratio to the SBD FBD involves the risk of fluidized bed disruption, it must be avoided.

The fluidized bulk density, reactor central fixed part of the measured pressure drop upward I transection of a proportion to the height of this fixed portion. It should be understood that under certain conditions known to those skilled in the art, average values greater or less than the actual bed bulk density can be measured.

[0021] The present inventors have come a <br/> the concentration of coagulation <br/> shrinkage components in the gas stream flowing through the layer (condensable component) to increase beyond the point where there is a concentration of that If further increases were heading that can reach the point that can be identified as at risk of catastrophic failure in the process of its results. This point is characterized by irreversible low down in the fluidized bulk density with increasing fluid density that can condense in the gas. A gas stream containing the monomers entering the reactor (recycle in the following)
(Often referred to as stream) is not directly related. Under low in fluidized bulk density generally occurs with no corresponding change in the settled bulk density of the final product granules. Thus, the change in flow behavior reflected by a decrease in fluidized bulk density does not contribute to a permanent change in the characteristics of the polymer particles.

The condensable fluid concentration in the low bottom occurs gas fluidized bulk density depends on the type and other operating conditions of the polymer produced. For a given a type polymers and other working conditions, by monitoring the fluidized bulk density when the condensable fluid concentration in the gas increases, its density can be confirmed.

The fluidized bulk density, besides the condensable fluid concentration, can be determined, for example, as well as the gas and particle densities, temperatures and pressures, as well as the superficial velocity of the gas flowing through the reactor, the fluidized bed height and the product. Depends on other variables, including the sedimentation bulk density. Therefore,
In the test for determining the varying <br/> of fluidized bulk density that attributable to changes in condensable fluid concentration in the gas must avoid significant changes in other conditions.

[0024] Some moderate low <br/> under the fluidized bulk density, without loss of control, but that obtained by adapting, raising the dew point temperature
Further changes in the gas composition and other variables that occur, along with the development of “hot spots” in the reactor bed and / or the formation of coalesced aggregates that eventually result in reactor shutdown, can result in a change in fluidized bulk density. results in a significant and irreversible low under.

[0025] Other actual impact directly related to low under the fluidized bulk density is lowered in the low lower polymer volume and constant polymer production rate of the fixed capacity reactor discharge system
Polymer / catalyst reactor residence time. For a given catalyst may decrease polymer / catalyst reactor residence time and catalyst productivity was low made, to increase the catalytic amount of residual product polymer. As a matter of fact the use of the invention, for cooling requirements associated with the reactor production rate and its predetermined target, it is desirable to minimize the condensable fluid concentration in the gas.

Using such a flow bulk density variable, a stable operating area is defined. Once a suitable composition has been identified, by cooling the composition to a higher degree,
The composition can be used to achieve much higher cooling capacity for the recycle stream ( without encountering bed instability) . Distill so determined stable operating zone
The Marase Rukoto, one holding quality good conditions in the fluidized bed, in order to achieve high reactor productivity, for special grades that, an appropriate amount of material that is not polymerized may condense. High reactor productivity is achieved in one way,
Or for the plant design, the plant a large capacity is changed so as to provide a relatively production capacity reactor is increased without changing the anti応器size or there may be designed in a small Sai reactor diameter that could be.

At higher reactor productivity, the fluidized bulk density
The amount of condensed fluid well in excess of 15%, 20% or even 25% when within the limits defined by changes in There has been heading that may be relevant.

Preferably, the fluidized bulk density, in parts of the fluidized bed not subjected to disturbances on the distributor plate
Observed by using a pressure difference measurement. The fluidized bulk density at the top, measured away from the distributor plate, is used to serve as a stable reference, and the variation of the traditional fluidized bulk density at the lower part of the bed is caused by the rupture of the bed above the distributor plate. It was considered as indicating, unexpectedly, the change in the top of the fluidized bulk density, which correlates to a change in the composition of the flow, may be used to look out and define stable operating region See
Was issued .

[0029] The cooling capacity can be increased in different ways. Preferably, the cooling capacity is increased by increasing the proportion of components that increase the dew point. It by low under the percentage of non-condensable inert material, as a percentage, or alternatively a non-polymerizable higher hydrocarbon components, increasing the proportion of the polymerizable monomer containing a comonomer having a carbon atom of 3 to 12 It is not accompanied by Rukoto. Where appropriate in a particular manner, for example by lowering the temperature of the fluidizing medium by cooling, may further increase the cooling capacity of the recycle stream. After determining a stable operating area, improved operating conditions are obtained.

Advantageously, the gas stream containing the monomers
Or a stream containing unreacted monomer gas is cooled to 40 Btu
/ Lb (200/9 cal / g) or more, preferably 50 Btu / lb (2
Pounds of polymer per ft ^{2 of} reactor cross section per hour with enthalpy change of the recycle stream from reactor inlet conditions to reactor outlet conditions of 50/9 cal / g or more
500lb When expressed in ^{s) / hr-ft 2 (} 2441kg / hr-
m ² ), especially 600 lb / hr-ft ² (2929 kg / hr-m
Cooling capacity for the reactor productivity of greater than ²⁾ at such a rate that is sufficient to pass the reactor the flow. Preferably, the liquid and gaseous components of the stream are added to the mixture below the reactor distributor plate. This reactor productivity is equal to the space-time yield multiplied by the height of the fluidized bed.

[0031] In one aspect of the present invention, under the fluidized layer
Gas velocities at and within are sufficient to maintain the suspended layer
Under such conditions, the recycle stream can be split into two or more separate streams, one or more of which can be introduced directly into the fluidized bed. For example, the recycle stream can be split into a liquid and a gas stream and then separately introduced into the reactor.

In the practice of the improved process of the present invention, by introducing separate liquid and recycle gas under conditions which produce a stream comprising both phases of gas and liquid phases, Disperse
Gas phase and liquid phase below the tributor plate (in the reactor)
The mixture can be formed recycle stream comprising a.

[0033] Ri by the Rukoto increasing the cooling capacity I by <br/> to carefully control the composition of the gas flow, it is possible to considerably increase in the reactor productivity. Problems resulting in fluidized bed destruction are reduced. % Of liquid in recirculating stream
Greater degrees of cooling can be used, even to the extent that a rate increase is provided. At a given percentage of the liquid in the recycle stream, the composition, temperature, pressure and superficial velocity of the gas in the reactor will affect the composition and physical properties of the product particles in order to maintain a viable fluidized bed. Must be controlled in relation.

[0034] In the method of the present invention, as a result of the greater temperature difference between the recycle stream which evaporates and enters the condensed entrained <br/> the recycle stream liquid and fluidized bed temperature, the recycle stream Can be significantly increased. 0.01 to 5.0,
Preferably a melt index of 0.5 to 5.0 and 0.90
A film grade polymer having a density of 0 to 0.930, or
0.10 to 150.0, preferably grade port molding having a density of melt index and 0.920 to 0.939 4.0 to 150.0
Reamers or polymers selected from high density polymers having a melt index of 0.01 to 70.0, preferably 2.0 to 70.0, and a density of 0.940 to 0.970 are suitably produced (all density units are g / cm ³ . , Melt index is g / 10 minutes as determined by ASTM-1238 condition E).

[0035] In the following description, like parts respectively is shown in the specification and drawings with the same reference numbers. The drawings do not necessarily have a common measure and certain parts have been enlarged to better illustrate the improved method of the present invention.

The present invention is not limited to a particular type or type of polymerization reaction, but may include one or more monomers such as ethylene, propylene, 1-butene, 1-butene.
Pentene, 4-methylpentene-1,1-hexene, particularly well adapted to function Azukasuru polymerization of olefin monomers such as 1-octene and styrene. Other monomers include polar vinyl, conjugated and non-conjugated dienes, acetylene and aldehyde monomers.

The catalyst used in the improved method includes a coordinating anion catalyst, a cationic catalyst, a free radical catalyst, an anionic catalyst, and a transition metal component or a single metal component reacted with a metal alkyl or alkoxy component or an ionic compound component. A metallocene component comprising one or more cyclopentadienyl components. These catalysts include partially and fully activated precursor compositions and those modified by prepolymerization or encapsulation.

As described above, the present invention provides
Of but not limited to a particular type of polymerization reaction, the following description of the operation of the improved process primarily olefin type monomers such as ethylene, is directed to the polymerization, at the polymerization the present invention, it has been heading is particularly advantageous.

The operating temperature of the process is set or adjusted to a temperature below the coalescence or sticking temperature of the polymer particles produced. Maintaining that temperature is important to prevent clogging of the reactor due to polymer chunks that grow rapidly at higher temperatures. Chunks of polymer can be too large to be withdrawn from the reactor as a polymer product, resulting in a method and reactor failure. Also, below
The yanking into the part of the stream that handles the polymer product is
For example, it destroys the transfer system, the drying device or the extruder.

[0040] The significant increase in the reactor productivity is possible by the practice of the improved fluidized bed polymerization of the present invention a sense Contact Keru quality or characteristics of the product without changing. In a preferred embodiment, the entire polymerization process of the present invention is performed continuously.

[0041] Because of the high cooling capacity and higher reactor productivity than increases the dew point of the recycle stream, to increase greater heat removed from the fluidized bed desirable. The dew point of the recycle stream increases the operating pressure of the reaction / recycle system, as disclosed by Jenkins et al. In U.S. Patent Nos. 4,588,790 and 4,543,399.
Or percentage of condensable fluid to increase, Ru non percentage of condensable gas of Re enhanced et by low under <br/> in the recycle stream. Condensable fluids catalyst is Ru inert der towards the reactants and the polymer produced products, but may also include comonomers. The condensable fluid is introduced into the reaction / recirculation system at any point in the system as shown by FIG. An example of a suitable inert condensable fluid is a readily volatile liquid hydrocarbon, which may be selected from saturated hydrocarbons having 2 to 8 carbon atoms. Some suitable saturated hydrocarbons are propane, n-butane, isobutane, n-pentane, isopentane, neopentane,
n- hexane, isohexane, and other saturated C ₆ hydrocarbons, n- heptane, n- octane and other C ₇ and C ₈ hydrocarbons or mixtures thereof. The preferred inert condensable hydrocarbons are C ₅ and C ₆ saturated hydrocarbons. Condensable fluids also include some of the above monomers that may be partially or wholly incorporated into the polymer product.
Umate, olefins, that obtained also contains polymerizable condensable comonomers such as diolefins.

[0042] In the practice of the present invention, the form to the recycle stream enters the fluidized layer, the mixture liquid phase to the gas phase were suspended
There dripping coercive and must be maintained on the amount and re speed of the circulation flow is sufficient level of gas in the reactor under the head (bottom head) recycle stream so as not to accumulate beneath the distributor plate liquid . Also, the rate of the recycle stream, a fluidized bed of the reactor supports, must be high enough to mix. It is also desirable that the liquid entering the fluidized bed be rapidly dispersed and evaporated.

It is important to control the gas composition, temperature, pressure and superficial velocity in relation to the composition and physical characteristics of the polymer. A viable fluidized bed should be suspended and stable under reactive conditions without the formation of appreciable amounts of aggregates (chunks or sheets) that would disrupt the reactor or downstream process operations. Is defined as the fluidized bed of particles that have been mixed.

[0044] more than 15% by weight of the recycle stream, either be condensed or as long as it does not exceed the safe operating limit boundary stable operation region that is determined by measurement of the fluidized bulk density, the disruption of the flow process encounter without, it is in the liquid phase state.

[0045] During the polymerization process, (typically, less than about 10%) small proportions Ru toward flow <br/> upward direction a fluidized bed gas phase reacts. Multi proportion of flow that does not react, going through the upper region of the fluidized bed called the freeboard region is a speed reduction region. In the freeboard area, the explosion of bubbles at the surface comes to the top of the fluidized bed or is accompanied by gas flow
The resulting large solid polymer particles are returned to the fluidized bed .
Small solid polymer particles, known in the industry as " fines", have a final settling velocity of
It is recovered together with the recirculated stream because it is less than the velocity of the recirculated stream in the zone .

[0046] In one preferred embodiment of the present invention provides a homogeneous flow of the recycle stream, in order to maintain the fluidized bed in suspension and, homogeneous recycle stream passing toward the fluidized layer above Preferably, the inlet of the recycle stream is below the fluidized bed in order to assure its stability.

In another embodiment of the invention, the recycle stream is split into a liquid component and a gas component that are separately introduced into the reactor.

The advantages of the present invention are not limited to the production of polyolefins. Thus, the present invention can be implemented for all exothermic reactions that take place in a gas fluidized bed. An advantage of the method operations in condensed form over other methods, the dew point temperature of generally recycle stream by close to the interior of the reaction temperature of the fluidized layer increases directly. In certain dew point, advantages of the method, the percentage of liquid in the recycle stream back to the reactor, increases directly. The present invention allows for a high percentage of the liquid used in the method.

The specially well suited gaseous fluidized bed reactor to the polymer produced by the method of the invention, the accompanying drawings in odor
Te, indicated generally by the numeral 10 in FIG. 1. FIG.
It should be noted that the reaction system shown in is only exemplary. The present invention is well suited to any conventional fluidized bed reaction system.

Referring to FIG. 1, a reactor 10 comprises a reaction zone 12
And, in this case, a free board area which is also the speed reduction area 14. The ratio of height to diameter of the reaction zone 12 can vary depending on the desired production volume and residence time. The reaction zone 12 includes a fluidized bed containing growing polymer particles, existing generated polymer particles and a small amount of catalyst. The fluidized bed in reaction zone 12 is generally maintained by recycle stream 16 generated from feedstock and recycle fluid. The recycle stream enters the reactor through a distributor plate 18 that helps maintain a uniform fluidization and a fluidized bed in the reaction zone 12 at the bottom of the reactor. In order to maintain the suspended reaction zone fluidized bed 12 in a continuous state, the superficial gas velocities of the gas streams are maintained.
ocity) (SGV) is typically about 0.2 ft /
Sec (0.061m / sec) to exceed the minimum flow amount required for the flow is 0.5 ft / sec (0.153m / sec). Preferably, SGV
Is greater than about 0.7 ft / sec (0.214 m / sec), preferably 1.
It must be maintained even above 0 ft / sec (0.305 m / sec). SGV is preferably 5.0 ft / sec (1.5 m /
Sec), especially 3.5 ft / sec (1.07 m / sec).

The polymer particles in the reaction zone 12 are localized
Been help "hot spots" prevention and the Ru is confined and distributed the catalyst particles in a fluidized bed. The start of the operation
When, before the recycle stream 16 is introduced into the reactor 10,
Seed polymer particles are provided. The polymer particles are preferably the same as the new polymer particles produced, but if different, are recovered with the newly produced first product after the recycle and the start of the catalyst stream and after the reaction has been established. This mixture generally has different properties,
Essentially it is divided from the new product after. The catalyst used in the improved process of the present invention is usually oxygen-sensitive, so the catalyst is preferably inert to the stored catalyst, such as but not limited to nitrogen or argon. coated under gaseous not a catalyst reservoir 20
Stored in

The fluidization of the fluidized bed in the reaction zone 12 is such that the recycle stream 16 is directed toward and through the reactor 10
Is achieved by high speed. Typically, in operation,
The speed of the recycle stream 16 is approximately 10 to 50 times the rate at which feed is introduced into the recycle stream 16. High recirculation flow 16
The high velocity provides the necessary superficial gas velocity to suspend and mix the fluidized bed in the reaction zone 12 under fluidized conditions.

[0053] fluidized bed involves dense population of individually moving rather particles caused by percolation and the bubbles of the gas in the fluidized layer, general appearance similar to the appearance <br/> liquid that boil vigorously Having. Recycle stream 16 is reaction zone 12
There is a pressure drop as it passes through the fluidized bed at. This pressure drop, reaction zone 12 the weight of the fluidized bed in the reaction応域12
Equal to or slightly larger than the cross-sectional area of
Therefore, Ru Tei made dependent pressure drop in the shape of the reactor.

Referring again to FIG. 1, the feed enters recycle stream 16 at, but not limited to, section 22. Gas analyzer 24 receives a gas sample from recycle stream 16 line and monitors the composition of recycle stream 16 passing therethrough. The gas analyzer 24 is also adapted to control the composition of the recycle stream 16 line and feedstock, and to maintain the composition of the recycle stream 16 in the reaction zone 12 stable. Gas analyzer 24 typically includes freeboard area 14 and heat exchanger 26.
During the period, preferably between the compressor 28 and the heat exchanger 26, a sample taken from the recycle stream 16 is analyzed.

[0055] recycle stream 16 passes towards the reaction zone 12 at the top of the heat generated by this polymerization how with absorption. The portion of the recycle stream 16 that is not reacting in the reaction zone 12 exits the reaction zone 12 and passes through the freeboard zone 14.
As previously described, this region, at a speed reduction region 14, most of have been accompanied polymers, fluidized bed reaction zone 12
And thereby the recycle flow of solid polymer particles
The amount carried over the 16 line Ru is reduced. As the recycle stream 16 once withdrawn from the reactor at the top of the freeboard region 14, then is compressed in the compressor 28, it passes through the heat exchanger 26. Recycle stream 16 to reaction zone 12 in reactor 10
Before returning, in the heat exchanger 26, it is removed from the heat and gas compressor product recycle stream 16 produced by the polymerization reaction. Heat exchanger 26
It is conventional in type, a vertical or horizontal position, may be disposed in the recycle stream 16 in the line. In other aspects of the present invention may include more than one heat exchange zone or compression zone in the recycle stream 16 in the line.

Returning to FIG.Immediately
To,Recycle stream 16 returns to the bottom of reactor 10. Preferably
The fluid flow deflector 30 is a gas distributor
It is located below the plate 18. The fluid flow deflector 30
Replaces the polymerPrevents sedimentation into a solid mass, and
Recirculation flow 16 below one distributor plate 18
WithinLiquid and polymer particlesKeep. preferable
Fluid flow deflectors of type are circular disks,For example,
This is the type described in U.S. Pat. No. 4,933,149. Ring
The Ip disk has a central upward flow and an outer peripheral flow
Give both. Above its centerTurn toThe flow is under the head
DepartmentDroplets insideofAccompanyingHelp the flow around the outer head
Helps minimize polymer particle deposition at the bottom
You. Distributor plate 18 recirculates stream 16
SpreadLetIn the reaction zone 12, causing the fluidized bed to collapse
ToMaybe,Centered onTowardsMoving flow
Or jetAnd the flow isReaction zone 12Flowing intoAvoid
You.

The temperature of the fluidized bed is set depending on the sticking point of the particles, but basically comprises three factors: (1) the catalyst activity and the introduction of a catalyst for controlling the polymerization rate and the rate of heat generation associated therewith. (2) the recycle stream introduced into the reactor and
Temperature Preparation flow (makeup stream), the pressure and composition, and
(3) depending on the volume of recirculation flow through the fluidized bed. The liquid evaporated in the reactor, because it helps to reduce the temperature of the fluidized bed, with recycle stream or by separate introduction as described previously, the amount of liquid introduced into the fluidized bed, in particular, to a temperature affect. Normally, the rate of catalyst addition is used to control the raw Narusoku of the polymer.

In a preferred embodiment, the temperature of the fluidized bed in the reaction zone 12 remains stable and constant by continuously removing the heat of reaction. Der reactor temperature is constant
That state arising when the quantity and balance of heat quantity of heat generated in the process is removed can be taken. This constant condition requires that the total amount of material entering the polymerization process be balanced with the amount of polymer and other materials removed . As a result, the temperature, pressure and composition at a given point in the method are stable over time. Temperature gradient is not critical in most fluidized bed in the reaction zone 12, but the bottom of the fluidized bed reaction zone 12 in the region above the gas distributor plate 18 is <br/> temperature gradient. This gradient results from the difference between the temperature of the fluidized bed in the temperature and reaction zone 12 of the recycle stream 16 which have contact the bottom of the reactor 10 entering through <br/> distributor plate 18.

[0059] The efficient operation of the reactor 10 is based on the recycle stream
Requires 16 good distribution . If the growing or produced polymer and catalyst particles settle out of the fluidized bed, polymer fusion can occur. This, in extreme cases, results in the formation of a solid mass in the reactor. Industrial size reactors contain thousands of pounds or thousands of kilograms of polymer solids at any given time. Removal of a solid mass of polymer of this size is very difficult and requires substantial effort and extended downtime. By determining stable operating area with the aid of FBD measurements, improved polymerization process flow and support of fluidized bed in the reaction zone 12 in reactor 10 is maintained can be achieved.

[0060] In a preferred embodiment of the present invention, this in order to obtain the benefit of reactor cooling capacity was increased in the polymerization how, liquid introduced into the reactor 10 is vaporized. As liquid higher abundance in the fluidized bed, which promotes the formation of aggregates that can not be broken by mechanical forces present in the layer
It can lead to potentially de-fluidize, layer destruction and reactor stopped. Alternatively, the method of this, since essentially the layer during requires that the temperature in the first <br/> constant, the presence of liquid,
Affects local layer temperature and affects the ability of the process to produce polymers with consistent properties . For this reason, they are introduced into a fluidized bed under a given set of conditions.
The amount of liquid to be deposited depends on the area below the fluidized bed (here
Of recirculating flow through the distributor plate
The mechanical forces associated with entry are shaped by the liquid-particle interaction.
Sufficient to break up the formed aggregates)
It must not be greater than the amount that evaporates.

[0061] In the present invention, the, through the layer flow for a given predetermined if not composition and physical characteristics and so or related reactor and recycle conditions of the product particles in the fluidized bed <br / > by defining the boundary conditions associated with the composition of the gas Ru, viable fluidized bed, Ru is maintained at not higher cooling level obtained <br/>.

[0062] Low below that observed in the fluidized bulk density,
For reasons that are not entirely clear, the expansion of the dense particulate phase and
Reflects changes in bubble behavior in the fluidized bed.

[0063] Returning to FIG. 1, when the catalyst used is required catalyst activator, it is generally added to <br/> downstream than the heat exchanger 26. Catalytic activator may be introduced into recycle stream 16 from dispenser 32. However, with the improved method of the present invention, there is no restriction on the location of the insertion of other necessary components such as catalyst activators or catalyst promoters.

[0064] The catalyst from the catalyst reservoir is separated at a favorable rate.
Part is more on top of the gas distributor plate 18
At 34, the fluidized bed reaction zone 12 may be charged intermittently or continuously. As noted above, in a preferred embodiment, the catalyst is loaded in the fluidized bed 12 at the point where mixing with the polymer particles is best achieved. Because some catalysts are very active, the preferred introduction into the reactor 10 is not toward the bottom of the gas distributor plate 18, must not above one. Introduction of catalyst in the area below side of the gas distributor plate 18 is obtained led to polymerization of product in this area, after all, resulting in clogging of the gas distributor plate 18. Also, introducing the catalyst above side of the gas distributor plate 18, forms help a homogeneous distribution of the catalyst in the fluidized layer 12, resulting from a station plant specific high <br/> catalyst concentration "hot spots" Help eliminate. Introduction, preferably, intends row to a more lower portion of the fluidized bed in the reaction zone 12. This gives a homogeneous distribution of the catalyst, packed polymerization is finally recycled line及 beauty heat exchanger
It may result in words, to minimize the carry over to the catalyst recycle line.

[0065] Various techniques related to introduction of the catalyst, for example,
Techniques described in U.S. Patent No. 3,779,712 is Ru employed in the improved process of this invention. This patent is incorporated herein by reference. Catalyst in fluidized bed reaction zone
For transport, an inert gas such as nitrogen or an inert liquid that readily volatilizes under reactor conditions is preferably used.
You . The rate of catalyst introduction and the monomer concentration in the recycle stream determine the rate of polymer formation in the fluidized bed reaction zone 12 . By adjusting the catalyst introduction rate into a single, it is possible to control the production rate of polymer produced.

Reactor using the improved method of the present invention
In a preferred operation mode of 10, by collecting a portion of the polymer product at a rate that matches the production of the polymer product, the height of the fluidized layer is maintained in the reaction zone 12.
Instrument for detecting changes in temperature or pressure in reactor 10
The use of is useful for monitoring changes in fluidized bed conditions in the reaction zone 12. Further, for the night or automatic adjustments to human temperature velocity or recycle stream of the catalyst introduction, the instrument is used.

In the operation of the reactor 10, the product
Remove from the reactor at 36 . After recovery of the polymer product, the fluid is preferably separated from the polymer product.
Recycle stream 16 Rye in the portion 38 of the fluid as a gas
And / or may be returned to the recycle stream 16 line as liquid condensed in section 40. The polymer product is routed downstream in section 42 to downstream processing .
On top of it . Recovery of polymer product, have name limited to the method shown in FIG. Figure 1 is merely an example a special method of recovering one <br/>. Other recovery systems, for example,
US Patent No. 4,5 , issued to Jenkins et al.
The systems described in US Pat. No. 43,399 and US Pat. No. 4,588,790 can be used.

According to the present invention, the recirculated stream is moved below its dew point.
Until cooled, by returning the recycle stream obtained in the reactor, a method for increasing the reactor productivity of manufacture of polymer <br/> chromatography on fluidized bed reactor using an exothermic polymerization reaction is provided Is done. 15% by weight to maintain the fluidized bed at the desired temperature
Recycle stream containing more liquid to reactor
It can be.

[0069] by the target substance, Do not have been previously recognized
Different recirculation conditions are employed, giving good productivity levels.

First, the recycle stream is between 0.00 and 0.60,
Preferably, a butene / ethylene molar ratio of 0.30 to 0.50, or a molar ratio of 4-methyl-pentene-1 / ethylene of 0.00 to 0.50, preferably 0.08 to 0.33, or 0.00 to 0.
A hexene / ethylene molar ratio of 30, preferably 0.05 to 0.20, or 1 of 0.00 to 0.10, preferably 0.02 to 0.07.
Having an octene / ethylene molar ratio of 0.00 to 0.4, preferably 0.1 to 0.3, of hydrogen / ethylene and an isopentane content of 3 to 20 mol% or an isohexane content of 1.5 to 10 mol%, Cooling capacity is 40 Btu / lb (20
0/9 cal / g) or more, preferably 50 Btu / lb (250/9 cal / g)
Or more or the amount of the condensed liquid is the 15 wt% or less
By the method under the above-mentioned conditions, for example, a film grade polymer is produced.

Second, the process is characterized in that the recycle stream has a 1-butene / ethylene molar ratio of 0.00 to 0.60, preferably 0.10 to 0.50, or 0.00 to 0.50, preferably 0.08 to 0.50.
4-Methyl-pentene-1 / ethylene molar ratio of 0.20 or hexene / ethylene molar ratio of 0.00 to 0.30, preferably 0.05 to 0.12, or 0.00 to 0.10, preferably 0.02.
1-octene / ethylene molar ratio of from 0.004 to 0.04
It has a hydrogen / ethylene molar ratio of 1.6, preferably 0.3 to 1.4 and an amount of isopentane of 3 to 30 mol% or isohexane of 1.5 to 15 mol%, and the cooling capacity of the recycle stream is
40 Btu / lb (200/9 cal / g) or more, preferably 50 Btu / lb
(250 / 9cal / g) or more, or the amount of condensed liquid is 15 weight
% With the proviso that more than a on, used to generate a molding grade polymers.

The recycle stream has a butene / ethylene molar ratio of 0.00 to 0.30, preferably 0.00 to 0.15, or
The molar ratio of 4-methyl-pentene-1 / ethylene of 0.00 to 0.25, preferably 0.00 to 0.12 or the molar ratio of hexene / ethylene of 0.00 to 0.15, preferably 0.00 to 0.07, or 0.00 to 0.05, preferably 0.00 to 0.05 1-octene / ethylene molar ratio of 0.02, 0.00 to 1.5, preferably 0.3
Hydrogen / ethylene molar ratio of 10 to 40 mol%
And the cooling capacity of the recycle stream is 60 Btu / lb (100 / 3cal
/ g) or more, preferably 73 Btu / lb (365 / 9cal / g) or more,
Most preferably at least 75Btu / lb (125 / 3cal / g) more than or the amount of the condensed liquid is the 12 wt% or less
The method in the condition that high density grade polymer is produced.

[0073]

Example 1 A fluidized gas phase reactor was operated to produce a copolymer containing ethylene and butene. The catalyst used was titanium chloride, tetrahydrofuran and magnesium chloride impregnated on silicon dioxide treated with triethylaluminum.
A complex of um, diethylaluminum chloride (0.50, Jichiru aluminum chloride molar ratio of chloride to tetrahydrofuran) and tri -n- hexylaluminum was reduced with (0.30, the molar ratio of tri -n- hexylaluminum to tetrahydrofuran) Things .
The activator is triethylaluminum (TEAL).

In Tables 1 and 2, andFIG.Pointing out toungue
The data isAdditional cooling required for high reactor productivity
To achieveIsopentane amountToGradually increaseLet
When,Reactor parameterschange ofIs shown. This embodimentso
Is an excess of isopentaneButBring about a change in the fluidized bed,
Eventually, "hot spots" and reactor shutdown
To form aggregatesThan,Causes fluidized bed destructionDoing
To. As the concentration of isopentane increases,VolumeLow densityunder
And its lowunderAlso results in an increase in layer height,flow
3 shows changes in layers. catalystThe percentageReductionLet,layerheightTo
LowLet down. Other attempts to reverse changes in fluidized beds
At,Isopentane concentrationToLowLet it downWas. But this
ofTimeAt this point, the height of the fluidized bed returned to normal,
With spots and aggregationWasLayer destruction is irreversible
Reactor shut downWhenbecame.

[0075]

[Table 1]

[0076]

[Table 2]

[0077] In addition, in the second experiment, Table 1 and
As predicted from Table 2, Tables 3 and 4 and FIG.
, When the concentration of isopentane increases gradually, fluidized bulk density is indicates that the decrease. However, this time, fluidized bulk density was gradually increased as a result of the concentration of isopentane is low down. Therefore, in this case, the change in fluidization in the layer is recovered were reversible.

[0078]

[Table 3]

[0079]

[Table 4]

Thus, the results shown in FIG. 4 and Tables 1-4 show that the change in fluidization of the bed due to the use of excess condensable fluid is not reversible. The range is clearly shown.
This range was defined as a range where the ratio of the fluidized bulk density of the bed in the reactor to the settled bulk density was less than 0.59. Clearly Example 1, unlike the disclosure by Jenkins et al., Regarding the useful condensable materials for optimal space-time yield and the reactor productivity of reactors operating in condensed form
It shows that there is a limit.

[0081] In Example 2 the following examples, carried out in Example 1 and the essentially the same manner using the same type of catalyst and activator have various density and melt index range, homopolymers and ethylene / A butene copolymer was formed.

[0082]

[Table 5]

[0083]

[Table 6]

[0084] These experiments are at least 0.59, while maintaining the ratio of fluidized bulk density to settled bulk density, 20
In condensed liquid amount in excess of weight%, and shows the advantage of achieving a reactor productivity has high.

For example, for downstream processing steps such as product recovery systems, extruders, etc., do not exceed overall equipment capacity .
Particular reactor conditions in cormorants must be processed successfully. Therefore, the complete advantages of the present invention are shown in Tables 5 and 6.
Completely it can not be evaluated me by the embodiment shown in.

[0086] For example, in Experiment 1 in Table 5 and Table 6,
Superficial gas velocity is kept low to approximately 1.69Ft / sec (0.52 m / sec), thus, space-time yield, which is reflected, not much smaller than in the other. Increase the speed to about 2.4 ft / sec (0.7
If maintained at 3m / ^{sec), 15.3lb / hr-ft 3} (245.4kg / hr
be empty TokiOsamu amount is achieved as estimated exceeds -m ³⁾
I can't . Table 5 and Experiment 2 and 3 of Table 6, in the high altitude tower gas velocity and 20% by weight more fully multi have condensed substance amount, shows the effect of operating a reactor. Space-time yields achieved were approximately 14.3 and 13.0 lb / hr-ft ³ (228.8 and
Fine 208.0kg / hr-m ³⁾ and is, in this, showed a significant increase in the production rate. Such high space-time yields or production rates are not taught or suggested by Jenkins et al. Similar to Experiment 1, Experiment 4 in Table 5 and Table 6,
Have you in the condensed liquid amount of 21.8% by weight 1.74ft / sec (0.53m /
It shows the case is a superficial gas velocity of a second). When the speed in Experiment 4 was increased to 3.0Ft / sec (0.91 m / sec), space-time yields achievable, 13.3lb / hr-ft ³ 7.7 ^(123.2 or
To 213.0 kg / hr-m ³ ) . Speed in the experiment 5
When increased to 3.0 ft / sec (0.91 m / sec) , the achievable space-time yield is 9.8 to 17.0 lb / hr-ft ³ (157.2 to 272.3
kg / hr-m ³ ) . All Te with <br/> in experiments 1-4, the ratio of fluidized bulk density to settled bulk density was maintained above at least 0.59.

[0087] In order to predict the prophetic example 3 target conditions, by the use of a known thermodynamic equilibrium equations in the art, is estimated based on information from actual operation, in Example 3 It made the data that Ru shown in tables 7 and 8 for the case. The data in Tables 7 and 8 demonstrate the benefits of the present invention, except for the limitations of the co-reactor unit.

[0088]

[Table 7]

[0089]

[Table 8]

[0090] In Experiment 1, the superficial gas velocity is, 1.69ft / sec.
(0.52 m / sec) has been increased to 2.40Ft / sec (0.73 / sec) from this is the first ^{10.8lb / hr-ft 3 (172.8kg} / h
rm ³ ) higher than 15.3 lb / hr-ft ³ (245.4k
It is cod also the space-time yield of g / hr-m ^3). In a further step, the inlet temperature of the recycle stream is cooled from 46.2 ° C to 40.6 ° C. This cooling reduces the amount of condensed matter in the recycle stream by three.
Increased to 4.4% by weight to 18.1 lb / hr-ft ³ (290.3 kg / hr-m
To ^3), thereby additionally improving the space-time yield. In the final step, the gas composition is changed by increasing the concentration of condensable inert isopentane, thereby improving the cooling capacity. By this means, the amount of condensed matter in the recycle stream is
Further increase to 44.2% by weight, space-time yield is 23.3 lb / hr-ft
³ (372.2 kg / hr-m ³ ) . Overall, the increase step provides a 116% increase in production capacity from the reactor system.

[0091] ActualTrialIn 2Is, RecirculationFlowInlet temperature
Is cooled from 42.1 ° C to 37.8 ° C. This cooling is recirculated
Amount of condensed matter in the flowIncreased from 25.4% to 27.1% by weight
Let, Space-time yield from 14.3 to 15.6 lb /hr-ft³ (From 228.8
249.9kg / hr-m ³ )Increased toLetYou.even moreIn the process,
C₆Hydrocarbon concentration increased from 7 mol% to 10 mol%Sa
Have beenYou. This improvement in cooling capacity reduced STY to 17.8
lb / hr-ft ³ (284.4kg / hr-m ³ )Increased toLetWas. This break
To show a good value,As a final step,RecirculationFlowEntering
The mouth temperature is again reduced to 29.4 ° C. This additional cooling
Condensation of recirculating flowSubstance quantityEmpty when reaches 38.6% by weight
Time yield 19.8lb /hr-ft ³ (317.6kg / hr-m ³ )ToLet
You. Overall, the augmentation step is based on the production capacity from the reactor system.
Gives a 39% increase in power.

[Brief description of the drawings]

1 is a schematic illustration of the reactor of the preferred embodiments used in the practice of the improved gas fluidized bed polymerization how for the production of polymers of the present invention.

FIG. 2 is a plot of isopentane concentration ( mol% ) versus fluidized bulk density versus time in Tables 1 and 2.

FIG. 3 is a plot of isopentane concentration ( mol% ) versus fluidized bulk density versus time in Tables 3 and 4.

FIG. 4 is a plot comparing FIG. 2 and FIG. 3;

DESCRIPTION OF SYMBOLS 10 reactor 12 reaction zone 14 freeboard area 16 recirculation flow 18 distributor plate 20 catalyst reservoir 24 gas analyzer 26 heat exchanger 28 compressor 30 fluid flow deflector 32 dispenser 36 recovery system

────────────────────────────────────────────────── ─── Continued on the front page (72) John Robert Griffin, Inventor, Pin Oak Drive, Baytown 77520, Texas, United States 225 (58) Fields studied (Int. Cl. ⁷ , DB name) C08F 2 / 00-2/60

Claims (14)

(57) [Claims] 1. Passing a gaseous stream containing monomers through a fluidized bed reactor under reactive conditions in the presence of a catalyst to produce a stream containing polymerization products and unreacted monomer gas. Compressing and cooling the stream containing the reactive monomer gas into a mixture of the gas and liquid phases, mixing the mixture with the feed components and returning the resulting gas / liquid mixture to the reactor Comprising, a gas fluidized bed polymerization method,
Cooling the stream containing unreacted monomer gas such that the weight of the liquid phase is greater than 15% by weight, based on the total weight of the mixture returned to the reactor; and A method for polymerizing a gas fluidized bed, which comprises having a composition such that a ratio of a fluidized bulk density to a settled bulk density in the reactor is more than 17.8 / 30.2 (≒ 0.59). 2. Cooling the stream containing unreacted monomer gas such that the weight of the liquid phase is greater than 20% by weight based on the total weight of the mixture returned to the reactor; The ratio of the fluidized bulk density to the settled bulk density in the reactor is 18.1 / 30.2 (≒
0.60) The method of claim 1, comprising having a composition that is greater than 0.60). 3. A stream entering the reactor, by increasing the dew point, in order to make the additional cooling comprises a non-polymerizable unsaturated hydrocarbons or mixtures thereof of a non-polymer having at least 3 carbon atoms, claims A method according to claim 1 or claim 2. 4. The non-polymeric non-polymerizable saturated hydrocarbon is
Propane, n- butane, isobutane, n- pentane, isopentane, neopentane, n- hexane, isohexane, and other saturated _{C 6} hydrocarbons, n- heptane, n- octane and other saturated _{C 7} and _{C 8} hydrocarbons or their 4. The method of claim 3, wherein the method is selected from a mixture of 5. A gas stream containing monomers or unreacted
The stream containing monomer gas cooled reactor productivity can be achieved is to pass its flow into the reactor at a rate in excess of ^{2441kg / hr-m 2 (500lb} / hr-ft 2), according to claim 1 or claim Item 3. The method according to Item 2. 6. A reactor having a productivity of 2929 kg / hr-m ² (600 lb.
/ Hr-ft ²⁾ at a rate in excess of passing the flow to the reactor The method of claim 5. 7. The reactor has a distributor plate, adding the liquid components and gaseous components of the flow in the mixture under the reactor distributor plate,
The method according to any one of claims 1 to 6. 8. A melt index of 0.5 to 5.0 and a melt index of 0.5.
Film grade polymer having a density of 900 to 0.930, 4.
A polymer selected from a molding grade polymer having a melt index of 0 to 150.0 and a density of 0.920 to 0.939, and a high density polymer having a melt index of 2.0 to 70.0 and a density of 0.940 to 0.970 is produced. The density unit is g / cm ³ , and the melt index is measured according to ASTM-1238 condition E, and the unit is g / 10 minutes.)
The method according to claim. 9. The polymerization product is a film-grade polymer, and the gas stream containing monomers recycled to the reactor (hereinafter referred to as the recycle stream) has a butene / ethylene molar ratio of 0.00 to 0.60. Or, the molar ratio of 4-methyl-pentene-1 / ethylene of 0.00 to 0.50, or 0.00 to 0.30
Hexene / ethylene molar ratio of
It has an octene / ethylene molar ratio, a hydrogen / ethylene molar ratio of 0.00 to 0.4 and an isopentane amount of 3 to 20 mol% or an isohexane amount of 1.5 to 10 mol%, and a cooling capacity of the recycle stream of 200/9 cal / 7. The method according to claim 5 or claim 6, wherein the method is not less than g (40 Btu / lb). 10. The recycle stream has a butene / ethylene molar ratio of 0.30 to 0.50, a 4-methyl-pentene-1 / ethylene molar ratio of 0.08 to 0.33, or a hexene / ethylene molar ratio of 0.05 to 0.20. Or a 1-octene / ethylene molar ratio of 0.02 to 0.07, a hydrogen / ethylene molar ratio of 0.1 to 0.3, and a cooling capacity of the recycle stream of 250/9 cal.
The method according to claim 9, wherein the amount is 50 g / g (50 Btu / lb) or more. 11. The polymerization product is a molding grade polymer and the recycle stream has a butene / ethylene molar ratio of 0.00 to 0.60 or 4-methyl-pentene-1 / 1 / 0.000 to 0.50.
The molar ratio of ethylene or a molar ratio of 0.00 to 0.30 hexene / ethylene or 1-octene / ethylene molar ratio of 0.00 to 0.10, the molar ratio of 0.00 to 1.6 hydrogen / ethylene and 3 to isopentane amount of 30 mol% Or has an isohexane content of 1.5 to 15 mol% and the cooling capacity of the recycle stream is
The method according to claim 5 or 6, wherein the method is at least 200/9 cal / g (40 Btu / lb). 12. The recycle stream may have a butene / ethylene molar ratio of 0.10 to 0.50, a 4-methyl-pentene-1 / ethylene molar ratio of 0.08 to 0.20, or a hexene / ethylene molar ratio of 0.05 to 0.12. Or a 1-octene / ethylene molar ratio of 0.02 to 0.04, a hydrogen / ethylene molar ratio of 0.3 to 1.4, and a cooling capacity of the recycle stream of 250/9 cal.
The method according to claim 11, wherein the amount is not less than 50 g / g (50 Btu / lb). 13. The polymerization product is a high density polymer,
Recycle stream, the molar ratio of 0.0 to 0.30 butene / ethylene or of 0.00 to 0.25 4-methyl - molar ratio of pentene-1 / ethylene or a molar ratio of 0.00 to 0.15 hexene / ethylene or 0.00 to 0.05 1-octene / ethylene molar ratio of 0.00 to 1.5 hydrogen / ethylene molar ratio and 1
It has an isopentane content of 0 to 40 mol% or an isohexane content of 5 to 20 mol% and a cooling capacity of the recycle stream of 100/3
The method according to claim 5 or 6, wherein the method is not less than cal / g (60 Btu / lb). 14. A butene / recycle stream having a flow of from 0.00 to 0.15.
The molar ratio of ethylene or of 0.00 to 0.12 4-methyl - molar ratio of pentene-1 / ethylene or a molar ratio of 0.00 to 0.07 hexene / ethylene or a molar ratio of 0.00 to 0.02 of the 1-octene / ethylene, 0.3 Hydrogen / ethylene molar ratio of ~ 1.0 and cooling capacity of recycle stream of 125 / 3cal / g
14. The method according to claim 13, which is at least (75 Btu / lb).