Method and device for gas-phase polymerization of alpha - olefins

 

(57) Abstract:

The invention relates to a method of gas-phase polymerization carried out in two vzaimosoedinenii areas polymerization, which serves one or more olefins of the General formula CH2=R in the presence of catalyst under reaction conditions and which is discharged polymer product. In the method of the invention the growing polymer particles pass through a first polymerization zone under conditions of fast fluidization, out of the specified zone and fed into the second polymerization zone. Through the second polymerization zone they are in aggregated form under the action of gravity and re-introduced into the first polymerization zone, thus creating a circulation of polymer through two zones of polymerization. The method allows to polimerizuet olefins in the gas phase with high productivity per unit volume of the reactor without the problems associated with fluidized bed technology. When this is achieved the flexibility of the process parameters can be optimized based on the characteristics of the catalyst and the product and are not limited to physical-chemical properties of liquid mixtures of the reaction components, expanding the product range. 2 C. imestusega in two interconnected polymerization zones, which in the conditions of polymerization are served by one or more-olefins CH2= CHR in the presence of a catalyst and of which unloaded the resulting polymer. In the method of the present invention of growing polymer particles pass through a first polymerization zone under conditions of fast fluidization, out of the specified zone and fed into the second polymerization zone through which they pass in aggregated form under the influence of gravity, out of the second specified area and re-introduced into the first polymerization zone, creating a circulation of polymer between the two polymerization zones.

The development of catalysts with high activity and selectivity type Ziegler-Natta and more and more applications of metallocene type has led to widespread use in industrial processes, in which the polymerization of olefins is carried out in a gaseous environment in the presence of the solid catalyst. Compared to the more traditional technology in a liquid suspension (monomer or mixture of monomer/solvent), this technology has the following advantages:

a) the flexibility of the process: the parameters of the reaction can be optimized based on the characteristics of Katalizator including hydrogen as a regulator of the degree of polymerization);

C) expansion of product range: the influence of swelling of the growing polymer particles and solubilization of the polymer fractions in the liquid medium significantly reduces the interval of receiving all kinds of copolymers;

(C) minimization operations polymerization downstream: the polymer is obtained directly from the reactor in the form of dry solids and requires simple operations for the removal of dissolved monomers and deactivation of the catalyst.

All the technologies developed to date for gas-phase polymerization of olefins, provide for the maintenance of a polymer layer, through which the reaction gases; this layer is maintained in suspension or mechanical agitation (reactor with a mixing layer), or fluidized bed resulting from recycling themselves of the reaction gases (reactor fluidized bed). In the reactors of both types, the composition of the monomer around the polymer particles in the reaction is maintained fairly constant due to forced mixing. These reactors are very closely approximate the ideal behavior of a flow reactor with stirrer (PFP), making it relatively easy control of the reaction and, therefore, ensuring consistency kachestvennoi technology is the technology using a reactor with a fluidized bed, working in conditions of "boiling". The polymer is limited in vertical cylindrical zone. The reaction gases leaving the reactor are taken centrifugal compressor, cooled and sent back together with fresh monomers and the corresponding quantities of hydrogen in the lower part of the layer through the dispenser. Ablation of solids in gas limited by obrazovanie the upper part of the reactor (excess, i.e., the space between the surface layer and a gas outlet, where the velocity of the gas is reduced, and in some designs the embedding of cyclones in the outlet gas line.

The flow rate of the circulating gas is set such as to ensure that the speed of fluidization in the appropriate range above a minimum velocity of fluidization and below the "transfer rate".

Reaction heat is removed solely by cooling the circulating gas. The components of the catalyst are served continuously. The composition of the gaseous phase regulates the composition of the polymer. The reactor operates at a constant pressure, usually within 1-3 MPa. The kinetics of the reaction is adjusted by the addition of inert gases.

A significant contribution to the reliability of the technology using artelino treated spheroidal catalyst of controlled size and use of propane as a diluent (see WO 92/21706).

The technology of fluidized bed has limitations, some of which are discussed in detail below.

A) the heat of reaction

The maximum speed of fluidization is an object with a fairly narrow limits (which causes the release of reactor volumes that are equal to or more volumes, filled with fluidized bed). Depending on the heat of reaction sizes of the polymer and the density of the gas, limit the performance of the reactor (expressed as hourly output per unit cross section of the reactor) are necessarily achieved where the operation temperature of the gas input is desirable. This deficiency can lead to performance degradation of the installation, in particular, in the copolymerization of ethylene with higher olefins (hexene, octene), which is carried out with conventional catalysts, Ziegler-Natta, requiring gas compositions, enriched by such olefins.

It was suggested many ways to address shortcomings in terms of heat dissipation, the traditional technology based on the partial condensation of the circulating gases and using the latent heat of evaporation of condensates to regulate the temperature inside the reactor especiany principle, turn the operation of the fluidized bed reactor critical.

In particular (and with the exception of the problems associated with the distribution of wet solids in the field of high pressure below the distribution grid), the technology used in patents EP-89691 and USP 5352749 based on the turbulence created by the grid at the distribution of liquid on top of the polymer. The possible phenomenon of coalescence in the area of high pressure can give rise to uncontrolled effects of poor distribution of the liquid with the formation of agglomerates that cannot be re-dispersed, in particular in the case of polymers, which tend to stick together. Exclusionary criteria described in the patent USP 5352749 reflects the situation at steady state, but does not offer actionable guidance for situations even unsteady "rejection" reaction, which can lead to irreversible loss of fluidization and subsequent failure of the reactor.

The method described in patent WO 94/28032, includes separation of condensates and their distribution over the grid using a special correspondingly spaced nozzles. Indeed, the condensates contain solids, any prevention on one nozzle requires a full shutdown.

B) Molecular weight distribution

As already established, fluidized bed shows a behavior that is directly comparable with a perfectly mixed reactor (PFP). It is well known that during the continuous polymerization of olefins in a single phase with stirring (which also includes the steady-state composition of the monomers and control degree of polymerization, usually hydrogen) with titanium catalysts of the type Ziegler-Natta get polyolefins having a relatively narrow molecular weight distribution. This characteristic is even more pronounced when using metallocene catalysts. The breadth of the molecular mass distribution has an effect on the rheological behavior of the polymer (and hence the processability of the melt), and the final mechanical properties of the product, and is a property that is especially important for copolymers of ethylene.

For the purpose of extending the molecular mass distribution determines the industrial importance of the processes on the basis of several reactors arranged in series, each cat is Strachowice for these processes, when you need a very wide molecular weight distribution, is the lack of homogeneity of the product. Especially critical is the homogeneity of the material in the processes of blown and in the production of thin films, in which the presence of even small amounts of inhomogeneous material leads to the presence of unmelted particles in the film ("fish eye"). In the description of the patent EP-574821 proposed system of two reactors, which operate in different polymerization conditions with mutual circulation of polymer between them. Despite the fact that the concentration is suitable for solving the problem of homogeneity of the product, as shown by experimental data, such a system requires capitalstream and has some complexity.

In other cases, the polymers with a broad molecular weight distribution are obtained by using mixtures of different catalysts of the Ziegler-Natta in a single reactor, each catalyst turns out to have a different sensitivity to hydrogen. It is clear that at the outlet of the reactor is obtained the mixture of granules, each of which has its own personality. This way is difficult to obtain homogenes developed rapidly in recent years, and a number of polymers obtained in this way, has expanded considerably. In particular, in addition to the homopolymers of ethylene and propylene, a wide range of copolymers can be obtained on an industrial scale, for example:

statistical copolymers of propylene with ethylene, propylene with ethylene and higher olefins and propylene with higher-olefins;

- polyethylene of low and very low density (LLDPE, PEEP), modified high - olefins containing 4 to 8 carbon atoms;

- heterophase copolymers with high impact strength obtained by growth on the active centers of the catalyst, at subsequent stages, one or more of the above polymers and ethylene-propylene or ethylene-butylene rubber; and

- EP and AGS - rubbers.

In short, the polymers obtained in the gas phase, the modulus of elasticity varies from 2300 MPa to values below 100 MPa, and the fraction soluble in xylene ranges from 1% to 80%. Fluidity, compatibility and adhesiveness, in turn, strongly vary as a function of degree of crystallinity, molecular weight and composition of the different polymer phases. Many of these products are crushed and fluid (and therefore processed) as long as they pastout statistical power between the individual solid particles. They seek more or less quickly Kotkovets and form aggregates, if they allow you to settle down or compacted in stagnant zones; this phenomenon is particularly increased in the reaction conditions, where due to the combined action of temperature and a large amount of dissolved hydrocarbon polymer is particularly soft, compressible and shared and sticky. Characterization of soft and sticky polymers effectively described in the patent EP-348907 or USP 4958006.

The most direct solution for discharging the polymer from the reactor consists of direct discharge from the fluidized bed through a distribution valve. This type of unloading polymer blends simplicity with the advantage of non-receipt of stagnant zones. When a sufficiently low pressure (in the range 50-300 kPa interval) is maintained below the discharge valve, the reaction practically stops either when the temperature drops due to evaporation of monomers dissolved in the polymer or due to the low partial pressure of the monomers in the gas thus avoiding any risk in cumulative equipment below the reactor.

However, it is known that the amount of gas extracted from the polymer of pseudoidentity solids in the layer, etc. (see, for example, Massimilla, "Flow properties of the fluidized dense phase", in "Fluidization" pp. 651-676, eds Davidson & Harrison, Academic, New York, 1971). Large amount of gas extracted from the polymer, are as kapitalistate and operational cost, you must re-compress the gas in order to compensate for the pressure of the reactor pressure receiver. In many industrial applications are periodic unloading system with placement of the at least two bins on alternate operations. For example, patent USP 4621952 describes the unloading system in which the polymer moves periodically and at high pressure drop of the reactor in the settling tank. The inertia of motion of the polymer, which is in the process of filling phase is confronted first with the wall of the settling of the reactor, and then with a layer of polymer, compresses the material that loses its fluid properties. During the stage of filling the pressure in the settling tank increases rapidly until the pressure in the reactor, and the temperature does not change significantly. The reaction proceeds and o adiabatically at high kinetics. With soft and sticky products that easily leads to the formation of agglomerates, which can not be crushed, followed tx2">

The disadvantages of the periodic system clearly manifested in the proposals advanced continuous systems. Japanese patent JP-A-58032634 involves the installation of an internal screw into the reactor to seal the polymer towards the discharge; patent USP 4958006 offers a set of extruder screws which feed directly inside the reactor fluidized bed. In addition to the complexity and difficulties of industrial applications of the proposed system in any case are quite unsuitable for feeding polymer in the subsequent step of the reaction.

Now, a new way of polymerization (and he is the first aspect of the present invention), which allows the olefins to polymerization in the gas phase with a high hourly output per unit volume of the reactor without the presence of problems of technology fluidized bed, the presently existing in the art. The second aspect of the present invention relates to a device for implementing this method.

Gas-phase polymerization method of the present invention is carried out in first and second interconnected polymerization zones, in which the polymerization conditions in the presence of a catalyst served one or Bolkhov unloaded the resulting polymer. The method is characterized by the fact that the growing polymer particles pass through the first of these zones polymerization in the fast fluidization, out of the specified first polymerization zone and proceed to the second of these zones polymerization, they are in aggregated form under the action of gravity, leave specified in the second polymerization zone and re-entered in the specified first polymerization zone, creating a circulation of polymer between the two polymerization zones.

As is known, the condition of fast fluidization is obtained when the speed pseudoviruses gas is higher than the speed of transfer, and differs in that the differential pressure in the direction of transfer is a monotonic function of the amount of the introduced solids at equal flow velocities and density pseudoviruses gas. In contrast to the present invention in the presently existing in engineering technology fluidized bed speed pseudoviruses gas is maintained substantially below the rate of transfer in order to avoid the phenomenon of capture solids and particle transport. The terms of transfer speed and status of fast fluidization is the ns Ltd., 1986".

In the second polymerization zone, where the polymer flows in a compact form under the action of gravity, to achieve high values of density of solids (density solids = kg polymer on m3the reactor employed polymer), which approximate the bulk density of the polymer; a positive increase in pressure can be obtained in the direction of flow, so that it becomes possible re-introduction of the polymer in the first reaction zone without the help of special mechanical means. Thus forms a "loop" circulation, which is determined by the balance of pressure between the two polymerization zones and falling pressure introduced into the system.

The invention is described with reference to the accompanying drawings, which are given for purposes of illustration without limiting the invention, where

in Fig. 1 shows schematically the method according to the invention;

in Fig. 2 schematically shows a first variant of the method according to the invention; and

in Fig. 3 schematically shows a second variant of the method according to the invention.

As shown in Fig. 1, the growing polymer passes through a first polymerization zone 1 in the fast fluidization in napri of gravity in the direction of arrow 14'. Two zones of polymerization of 1 and 2 respectively interconnected sections 3 and 5.

The material balance is maintained by the supply of monomers and catalysts and unloading of the polymer.

Usually the condition is fast fluidization in the first polymerization zone 1 is set by the feed gas mixture containing one or more-olefins CH2= CHR (line 10), in the indicated zone 1; preferably the feed gas mixture is below the point of re-injection of the polymer specified in the first zone 1 when using a gas distribution device, such as, for example, a distribution grid.

The transfer rate of the gas in the first zone of polymerization is higher than the transport velocity in the working conditions and is preferably 2-15 m/s, more preferably 3-8 m/s

The control polymer, circulating between the two zones polymerization is carried out by measuring the amount of polymer emerging from the second polymerization zone 2, with a device suitable for regulating the flow of solids, such as, for example, mechanical valves (spool valve, ball valve and so on) or mechanical valves (L-valve, J-valve, reversible seal and so on).

From the separation zone 4, the polymer is fed into the second polymerization zone 2. The gas mixture emerging from the separation zone 4, is compressed, cooled and transferred, if necessary, with addition of fresh monomer and/or molecular weight regulators in the first polymerization zone 1. This transfer can be implemented using line recycling 6 gas mixture, equipped with a compression device 7 and the cooling 8 and feeder monomers and molecular weight regulator 13.

Part of the gas mixture emerging from the separation zone 4, can move after cooling in the connection zone 5 via line 9 in order to facilitate the transfer of polymer from the second into the first polymerization zone.

Preferably, the various components of the catalyst are served in the first polymerization zone 1 at any point in the specified zone polymerization 1.

Particularly suitable are catalysts adjustable morphology, which are described in the patents USP 4399054, USP 5139985, EP-a-395083, EP-553805, EP-553806 and EP-601525, and, in General, catalysts, able to give examples in the form of spheroidal particles having an average size of from 0.2 to 5 mm, preferably 0.5 to 3 mm, the Method of the present invention is, furthermore, especially prty catalyst can be entered in one and the same point or at different points of the first polymerization zone.

The catalyst may be supplied without pre-treatment or in the form of a prepolymer. When other stages of polymerization are located upstream, in the polymerization zone can also nourish the catalyst dispersed in the polymer suspension coming from the top block flow reactor, or the catalyst dispersed in the dry polymer coming from the upper stream of gas-phase reactor.

The concentration of polymer in the reaction zone may be controlled by conventional methods, known in the art, for example by measuring the pressure difference between two corresponding points along the axis of the zones polymerization or by measuring the density of nuclear detectors (e.g., rays).

Operating parameters, such as temperature, are what are used in gas-phase methods for the polymerization of olefins, for example in the range of 50-120oC.

The method according to the present invention has many advantages. The configuration of the loop allows you to take a relatively simple configuration of the reactor. In practice, each reaction zone can be designed in the form of a cylindrical reactor with high aspect ratio (ratio of height pressure which are uneconomic in a traditional fluidized bed reactor. The method according to the invention can thus be implemented at operating pressures in the range of from 0.5 to 10 MPa, preferably in the range of 1.5 to 6 MPa. Resulting from the high density gas is promoted by the heat transfer on a single particle, and the total heat of reaction. So you can choose the working conditions that improve the kinetics of the reaction. In addition, the reactor through which the polymer takes place in the fast fluidization (the first polymerization zone can take full mileage when polymer concentrations that reach or exceed 200 kg/cm3. Taking into account the share of the second polymerization zone and taking into account more favorable kinetic conditions, which can be installed, the method of the present invention makes it possible to obtain specific generation (hour output per unit volume of reactor), which is much higher than the levels obtained by conventional technology fluidized bed. Thus, you can get equal or even surpass the catalytic outputs a traditional gas-phase methods using polymerization equipment NANOG is according to the invention the entrainment of solids in the line of recycle gas at the exit from the zone of separation of the solids and gas and the possible presence of a fluid, coming out of the fridge, on the same line do not limit the effectiveness of the first polymerization zone. Even when using a gas distribution device, such as, for example, the net rate of transfer of gas in the chamber below the grid are quite high, and such that provide drift even of considerable size and wet polymer without stagnation points. Provided that transports gas comes in contact with the stream of hot polymer coming from the second polymerization zone, the evaporation of any liquid is actually instant. Therefore, it is possible to cool the gas mixture emerging from the separation zone, solids and gas, to temperatures below the dew point to condense part of the gases. The mixture of gas/liquid, which is formed, is fed to the first polymerization zone, where it contributes to heat dissipation without problems and shortcomings of the existing analogues and without having to use complicated devices proposed in order to avoid them. In addition to and/or instead of the partial condensation of recirculating gases the method of the invention opens a new path for removal of heat of reaction. The distinctive geometry (high surface: volume) onyamaha heat transfer in this area (and, consequently, with a maximum heat transfer between the coolant and the reaction system). When convenient, additional or alternative heat transfer surfaces may be present inside the reactor, the first polymerization zone can then be advantageously cooled external cooling unit. High turbulence associated with the conditions of fast fluidization, and high density gas provide in each case a very high heat transfer coefficient. Any condensation on the inner walls continuously removes strong radial and axial mixing of the polymer due to the fast fluidization. In addition, this feature makes the technology suitable for use as a power of the second stage directly from the top block flow reactor. You can also apply a portion of fresh monomers in condensed form without any difficulty. As for removal of heat of reaction, that has a method of the invention, exceed the capabilities of existing analogues, and eliminates the disadvantages inherent in the known technologies. In addition, there is no need for the dependency of the volumetric velocity of cirea one or more inert gases in such quantities, that the sum of partial pressures of inert gases is preferably 5-80% of the total gas pressure. The inert gas may be nitrogen or an aliphatic hydrocarbon having 2 to 6 carbon atoms, preferably propane. The presence of an inert gas has numerous advantages, since it makes possible the slow reaction kinetics while maintaining at the same time, the total pressure of the reaction that is sufficient to maintain the low pressure circulation compressor and to ensure adequate flow rate mass for heat transfer to the particle layer through the refrigerator for circulating the gas mixture for removal of heat of reaction, which is not removed surfaces.

In the method of the present invention the presence of an inert gas has an advantage because it makes it possible to limit the growth temperature in the second polymerization zone, which is actually in the adiabatic form, and also makes it possible to adjust the breadth of the molecular weight distribution of the polymer, especially in the polymerization of ethylene.

That is why, as already established, the polymer flows vertically down through the second polymerization zone in the piston movement Purna weight of the polymer in the polymerization of ethylene is regulated by the ratio of the hydrogen : ethylene in the gas phase and to a lesser extent temperature. In the presence of inert gases, provided that the reaction consumes the ethylene and hydrogen only to a minor extent, the ratio of ethylene : hydrogen decreases along the axis of the polymer flow in the direction of movement, causing the growth of polymer fractions on the same particle with lower molecular masses. The temperature rise in the reaction helps this effect. Therefore, it is possible by proper balancing of the gas composition and the residual time in two polymerization zones to regulate effectively the breadth of the molecular mass distribution of polymers while maintaining maximum homogeneity of the product.

On the contrary, if it is desired to obtain polymers with a narrow molecular weight distribution, the above described mechanism may be limited or it can be avoided by appropriate choice of the reaction conditions, for example by limiting the amount of inert gas or by filing the appropriate amount of reaction gas and/or fresh monomer(s) in the relevant provisions in the second polymerization zone. Mainly gas supplied to the second polymerization zone may be selected from the gas mixture emerging from the separation zone solids and gastrostella speed put gas in relation to the speed of the moving solids is maintained below the minimum velocity of fluidization - the system features solid - gas present in the second polymerization zone. Under these conditions, reaching down stream of the polymer is not actually broken. Operational flexibility of the method of the invention is therefore complete, and the production of polymers of different molecular mass distribution is regulated by means of the gas composition and, if necessary, a simple closing or opening the valve on the gas line.

The polymer mainly can be discharged from the area where the density of a solid is higher, for example from the corresponding points in the second polymerization zone, where there are large quantities of compressed fluid polymer, in order to minimize the amount of blown gas. By installing valves in the corresponding point upstream of the site of release of the polymer from the second polymerization zone, it becomes possible to continuously monitor the destruction of the obtained polymer. The amount of gas accompanying the polymer is extremely small and only slightly larger than can be provided by device placement number of bins on alternate intermediate operations. Thus, to overcome the nature paged products.

As already established, the method of the present invention can be combined with traditional techniques in a sequential multi-stage method, in which upstream and downstream from the polymerization section operating according to the present invention, has one or more stages of polymerization, using traditional technology (in bulk or gas phase or in a fluidized bed, or in the mixed layer). Multistage ways in which two or more stages are implemented with the technology of the present invention are also possible.

In addition, it is possible to combine the method according to the present invention with the conventional gas-phase technologies fluidized bed by arrangement between the two polymerization zones, as defined in the present invention, the polymerization zone, use pseudocyesis layer, i.e. with the velocity of the fluidization gas is higher than the minimum velocity of fluidization, and lower than the transfer rate, while keeping the characteristics of the contour circulation method of the present invention. For example, one possible option would be that the second polymerization zone comprises first and second sections. Vya appropriate supply and distribution of gas; in the second section, respectively connected with the first zone, the polymer flows in a densified form under the action of gravity. From the second section of the polymer is re-introduced into the first polymerization zone, maintaining the contour circulation. With proper selection of the dimensions of the various zones, it becomes possible to ensure the expansion of the molecular mass distribution of polymer while maintaining all of the above advantages. The above example is only one of possible variants of the method of the invention, which in its General definition contains at least an area of fast fluidization, vzaimosoedineniyu zone, where the polymer flows in a compact form under the action of gravity.

The method of the present invention is applicable to obtain a large number of olefinic polymers without the above described disadvantages.

Examples of polymers that can be obtained are:

- high density polyethylene (HDPE, having a relative density higher 0,940), including homopolymers of ethylene and copolymers of ethylene and-olefins having 3-12 carbon atoms;

linear low density polyethylene (LLDPE, having a relative density below 0,940) and poly is 0,920 to 0,880), consisting of copolymers of ethylene with one or more-olefins having 3-12 carbon atoms;

elastomeric terpolymer of ethylene and propylene with a minimum proportions of diene or elastomeric copolymers of ethylene and propylene with a content of units derived from ethylene, about 30-70% by weight;

- isotactic polypropylene and crystalline copolymers of propylene and ethylene and/or other olefins having a content of units derived from propylene, more than 85% by weight;

- heterophase polymers of propylene obtained by the sequential polymerization of propylene and mixtures of propylene with ethylene and/or other olefins;

- atactic polypropylene and amorphous copolymers of propylene and ethylene and/or other olefins, containing more than 70 wt.%. units derived from propylene;

- poly - a-olefins, such as, for example, poly-1-butene, poly-4-methyl-1-penten;

- polybutadiene and other polydiene rubbers.

An additional aspect of the present invention relates to a device for gas-phase polymerization of olefins, which is shown in Fig. 1 - 3.

The device of the invention contains a first vertical cylindrical reactor 20, is equipped with a supply line catalysis is is the fact that the upper region of the first reactor 20 is connected to the first line 21 to the separator 22 separating a mixture of solid/gas, which, in turn, connects with the upper region of the second reactor 30, the lower region of the second reactor 30 is connected to the second line 31 with the lower region of the first reactor 20; and a separator 22 separating a mixture of solid/gas are connected with the line for recycling the gas mixture 36 to the first reactor 20 in region 37 in the bottom of the specified first reactor 20 below the insertion point and the second line 31.

Preferably the first reactor 20 is equipped with a gas distribution device 33, for example a grid located between the insertion point of the second line 31 and section 37 in the bottom of the reactor. Alternatively (see Fig. 3) gas distribution device in the first reactor 60 may be replaced by a cylindrical line 65, through which the gas flows at high speed and which is connected with the reactor 60 section in the shape of a truncated cone 62 with an angle of inclination to the vertical, and preferably less than 45oand, more preferably 10-30o. Mainly as a catalyst (line fill 66), and the polymer coming from the second reactor 70 through line 77, can be transported che the RA is usually installed between the second reactor 30 and the second line 31. This valve 24 may be either mechanical or non-mechanical type.

In the case when there is a gas distribution device 33, some or all of the components of the catalyst may preferably be entered on the third line 32 in the first reactor 20 at a point above the gas distributing device.

Line recycling the gas mixture 36 preferably is equipped with a compressor cooling system 27 and systems introduction, together or separately, monomers 28 and regulator of the molecular weight of 29. Can have two cooling systems, one above and the other below the compressor.

The first line 21 extends from the upper region of the first reactor preferably on the side, and noticed that the side exit of the mixture, the solid/gas from the first reactor 20 makes a significant contribution to the dynamic stability of the entire reaction system.

The upper region of the first reactor 20 may have a cylindrical shape with a diameter equal to the diameter of the reactor or, preferably, may be in the form of a truncated cone with the wide end at the top.

The first line 21 may be horizontal or have a inclination in the direction of gravity in order to facilitate in the from and can be connected (at the point directly downstream of the first valve 24 through line 25 from line recirculation gas 36 at a point downstream of the compressor 26. Thus, the flow of the polymer is accompanied by a flow of gas under pressure coming from the line of recycling, which helps avoid stagnant zones of the polymer in the line and the point of introduction into the reactor 20. The system of connection of the lower regions of the reactor may be of the type shown in Fig. 3, in which the circulation of the polymer obtained by pneumatic L-valve 74, triggered from the gas line recycling through line 75. L-valve is connected by line 77, which is in the first reactor 60 with the specified line 77 is connected through line 76 to line recycling 81. Along this line, the polymer returns to the inside of the reactor 60 via respective gas flow, going along the line 76.

The first reactor 20 can be advantageously equipped with an external cooling device 35, such as a wall-mounted heat exchangers.

Two possible variants of the invention are illustrated in Fig. 2 and Fig. 3. These options are purely illustrative and do not limit the invention.

In Fig. 2, the numeral 20 represents the first reactor working under fast fluidization, and 30 represents the second reactor, through which the polymer flows in a compact form under the force of tgest the R separation of solids and gas; 23 - discharge system of the polymer; 36 - line for recycling the gaseous mixture, which connects the specified separator with section 37 in the bottom of the first reactor; 24 - regulating valve for regulating the flow rate of the polymer; 33 - distribution device; a 32 - line submission of the catalyst; 26 - compressor and 27 - cooling system recirculates gas mixture; 28 and 29 of the supply system of the monomers and the molecular weight regulator; 25 - line, which connects line recycling 36 from line 31; 35 - external cooling system of the first reactor 20.

In Fig. 3 figure 60 represents the first reactor working under fast fluidization, and 70 represents the second reactor, through which the polymer flows in a compact form under the action of gravity; 71 and 77 lines connecting the upper and lower area of the two reactors; 66 - supply line of the catalyst; 72 - separator separation of solids and gas; 73 - discharge system of the polymer; 81 - line recycling of the gas mixture, which connects the specified separator 72 by line 65 connected to the base of the first reactor 60 section shape of a truncated cone 62; 74 - L-valve for regulating the flow rate of the polymer; 79 - compressor and 80 cooling gas which connects line recycling 81 line 77; 78 - the line that connects the line recycling 81 with a plot in the bottom of the second reactor 70; 61 - external cooling system of the first reactor 20.

The following additional examples illustrate the present invention without limiting its scope.

EXAMPLES

General conditions of polymerization

The polymerization is carried out continuously in the installation, has a section prior interaction, where different components of the catalyst are mixed in advance, the section terpolymerization and section of the gas-phase polymerization carried out in a reactor of the type shown in Fig. 2.

In the vessel prior interaction is preliminary interaction of the solid catalytic component obtained in accordance with the procedure described in example 3 of the patent EP-A-395083, triethylaluminum (TEA) and silane compounds in hexane at 10oC for 10 minutes Activated catalyst is fed into the section terpolymerization where polymerized propylene in suspension using propylene as a disperse medium. The monomer feed and the residence time is regulated so as to obtain the desired output terpolymerization, expressed in grams of polymer is olymerization. In the device described with reference to Fig. 2, contains two cylindrical reactor 20 and 30 connected by pipes 21 and 31. The reactor 20 is equipped with a heat exchanger 35. Fast fluidization in the reactor 20 is achieved by the gas from the separator separating solids and gas 22, reciklirawe in the bottom of the reactor 20 through line recycling gas 36. Naturally the device is not used, recyclorama gases are fed directly into the region 37 in the bottom of the reactor 20 below the point of entry of the pipe 31. Line recycling gas is equipped with a compressor 26 and a heat exchanger 27. Suspension of the prepolymer reactor connected to the reactor 20 at a point directly above the point of entry of the pipe 31. The circulation of the polymers is controlled by the L-valve 24 running from the gas stream 25 from the line of recycling 36. Fresh monomers are fed into the line for recycling 36. The polymer is continuously discharged from the reactor 30 through the pipe 23. The total volume of the device (i.e., reactors 20 and 30 plus joint zone 21 and 31) is equal to 250 HP

EXAMPLE 1

The polypropylene obtained by using a catalyst containing dicyclopentadienyliron (DCPMS) as a silane compound. On stage gas phase Polimeri is satisfactory interaction

- TEA/solid component (by mass) - 8

- TEA/DCPMS (by weight) - 3

Stage terpolymerization

Output (yoy) - 100

Gas-phase polymerization

- Temperature (oC) - 85

Pressure (kPa) - 2500

- Propylene (mol.%) - 91

- Propane (mol.%) - 8

- Hydrogen (mol.%) - 1

- Specific productivity (kg/FM3) - 140

Product feature

- Bulk density (kg/l) - 0,45

EXAMPLE 2

Modified hexane LLDPE produced using a catalyst containing cyclohexanedimethanol (CMMS) as a silane compound. On stage vapor-phase polymerization propane is used as the inert gas.

The main working conditions

Preliminary interaction

- TEA/T (mass.) - 120

- TEA/CMMS (mass.) - 20

Stage terpolymerization

Output (yoy) - 400

Gas-phase polymerization

- Temperature (oC) - 75

Pressure (kPa) - 2400

- Ethylene (mol.%) - 15

- 1/hexene (mol.%) - 1,5

- Hydrogen (mol.%) - 3

- Propane (mol.%) - 80,5

- Specific productivity (kg/FM3) - 80

Product feature

The melt index E (g/10 min) 1,4

Is the density (g/cm3) - 0,908

In the round equals 66oC. Circulating the coolant in the heat exchanger 35 is thus, to obtain the temperature of the 63oC on the surface of the reactor 20. Under these conditions, the gaseous mixture is partially condensed on the walls of the reactor, and thereby the heat of reaction. In the process, does not meet the pollution problem.

1. The method of gas-phase polymerization of olefins of General formula CH2= CHR, where R is hydrogen or a hydrocarbon radical having 1-12 carbon atoms, carried out in first and second interconnected polymerization zones, in which one or more of the following-olefins are served in the presence of a catalyst under reaction conditions and which is discharged polymer product, in which the growing polymer particles pass through the first of these zones polymerization come from the specified first polymerization zone and proceed to the second of these polymerization zones through which they pass, are out of the specified second polymerization zone and re-entered in the specified first polymerization zone, thus creating, circulation of polymer between the two polymerization zones, wherein these particles pass through the first AOR is on the action of gravity.

2. The method according to p. 1, in which the specified conditions of fast fluidization created by the flow of the gas mixture containing one or more of the following-olefins of General formula CH2= CHR, specified in the first polymerization zone.

3. The method according to p. 2, on which the specified gas mixture is delivered to the specified first polymerization zone at the site below the point of re-injection of the polymer specified in the first polymerization zone.

4. The method according to p. 3, whereby the flow of the specified gas mixture is carried out using a gas distributing device.

5. The method according to PP.1 to 4, in which the polymer and the gas mixture emerging from the specified first polymerization zone, transported to the zone of separation of solids and gas, and the polymer emerging from the zone of separation of solids and gas flows specified in the second polymerization zone.

6. The method according to PP. 1 to 5, in which the control polymer, circulating between these two zones polymerization is carried out by measuring the amount of polymer emerging from the specified second polymerization zone.

7. The method according to PP.1 to 6, in which the polymer is continuously removed from the specified second zone polymerizat is Itachi.

9. The method according to PP. 1 - 8, where each of the reaction zones is supplied with catalyst in terpolymerization form.

10. The method according to PP.1 to 9, where each of the reaction zones is supplied with a catalyst dispersed in a polymer suspension.

11. The method according to PP.1 - 10, where each of the reaction zones is supplied with a catalyst dispersed in a dry polymer.

12. The method according to p. 5, in which the gas mixture emerging from the zone of separation of solids and gas is compressed, cooled and transported in accordance with the addition of fresh monomer specified in the first polymerization zone.

13. The method according to p. 5, in which part of the gas mixture emerging from the zone of separation of solids and gas, is used for transferring the polymer from the second specified area specified in the first polymerization zone.

14. The method according to p. 5, in which part of the gas mixture emerging from the zone of separation of solids, compressed and transferred to the specified second polymerization zone near the area where the polymer goes from a specified second polymerization zone.

15. The method according to p. 12, in which the gas mixture emerging from the zone of separation of the solid is above the first polymerization zone is cooled by an external cooling device.

17. The method according to PP.1 - 16, in which fresh monomer or monomers are at least partially condensed form specified in the first polymerization zone.

18. The method according to p. 2, in which the speed pseudoviruses gas specified in the first zone of polymerization is 2 to 15 m/s, preferably 3 to 8 m/s

19. The method according to p. 1, in which the polymer is in the form of spheroidal particles having average sizes in the range of 0.2 to 5 mm, preferably 0.5 to 3 mm

20. The method according to p. 1, in which the operating pressure is 0.5 to 10 MPa, preferably 1.5 to 6 MPa.

21. The method according to p. 1, in which one or more inert gases is in the specified zones polymerization at a partial pressure comprising 5 to 80% of the total gas pressure.

22. The method according to claim .21 in which the inert gas is nitrogen or aliphatic carbon having 2 to 6 carbon atoms, preferably propane.

23. The method according to p. 1, in which the intermediate curing area, working with the fluidized bed, is located between the said first and the second polymerization zones.

24. Device gas-phase polymerization of olefins, containing the first vertical cylindrical reactory discharge system polymer (23), the upper area of the specified first reactor (20) connects the first line (21) with separator solids and gas (22), which, in turn, connects with the upper zone of the specified second reactor (30) and the lower area of the specified second reactor (30) is connected to the second line of (31) with the lower area of the specified first reactor (20), the specified separator solids and gas (22) is connected via a recirculation line of the gas mixture (36) with a first reactor (20), section (37) the lower part of the first reactor (20) below the insertion point and the specified second line of (31).

25. The device according to p. 24, wherein the first reactor equipped with a gas distribution device located between the insertion point of the second line and plot connecting the recirculation line to the bottom of the first reactor.

26. The device according to p. 25, characterized in that the supply line of the catalyst are connected by a third line to the first reactor at a point above the gas distributing device.

27. The device according to p. 24, characterized in that between the second reactor and the second line has a first control valve for regulating the velocity of the polymer.

29. The device according to p. 24, characterized in that the first control valve is a non-mechanical valve.

30. The device according to p. 24, characterized in that the recirculation line of the gas mixture is supplied by a compressor, a cooling system and introduction of the monomers and the molecular weight regulator.

31. The device according to p. 30, characterized in that the recirculation line of the gas mixture is connected through a line to the second line at a point below the compressor flow.

32. The device according to p. 24, characterized in that the upper zone of the first reactor is configured in the form of a truncated cone located wide end up.

33. The device according to p. 24, characterized in that the output of the first line from the upper zone of the first reactor is made to the side.

34. The device according to p. 24, wherein the first reactor is equipped with an external cooling device.

 

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