Process for manufacturing polymers in reactors with fluidized bed

PATENT DESCRIPTION

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Additional patent to patent no. Pending: 83 03 23. /P.241143/

Priority*. 82 03 24 United States of America

OFFICE

PATENT

PRL

BO 1J 8/18

The application was announced: 84 03 26

Patent description published: 1989 12 31

Creator of wY^onpatent holder: UNION CARBIDE CORPORATION,

Dnbury / United States ΑιθΓ ^ ί /

HOW TO MAKE POLBEYES IN REACTORS WITH FLUDGE

The subject of mw / Jnlazku is a method of balancing polymers in fluidized bed reactors, ensuring an increase in the capacity per unit of time and volume. Conducting the process of producing polymers in a fluidized bed resulted in a reduction in investment outlays and a huge reduction in energy demand compared to conventional processes. Known means of heat removal in conventional processes carried out in fl reactors are based on compression and cooling outside the recycle gas stream.

In industrially implemented flue bed reaction systems designed for balancing polymers such as polyethylene, the amount of fluid that needs to be recirculated to remove heat of polymerization is greater than the amount of fluid expelled to support the fluidized bed and for proper solid particle mill in fluid bed. The fluid velocity in the reactor is limited to prevent excessive entrainment of suspended solids. A constant bed temperature is obtained in 8 ohms, if the heat in / boils through the polymerization reaction / which is proportional to the glass. polymer formation bone »/, is equal to the heat absorbed by the fluddy-dying barnacle passing through this bed, plus the heat removed or otherwise lost.

For a long time, there was a perception that the temperature of the recycled gas should not be reduced more than to a slightly higher dew point temperature of the recycled gas stream. The dew point is the temperature at which liquid droplets begin to form in the gas stream · The usual practice was to limit the temperature of the recycle stream at the inlet from the cycle zone of the heat to a temperature of at least about 3 to 10 ° C above roey temperature / see European patent description No. 0021605, pp. 22, lines 8-22, which also corresponds to the patent application pending from the United States. Antyki nr 49555 / · This assumption is based on the conviction that the introduction

148 356 liquid into the reactor downstream of the fluidized bed gas phase will inevitably lead to clogging of the gas distribution plate, if used; and, moreover, will cause uneven distribution of monomer concentrations in the fluidized bed and accumulation of liquid at the bottom of the reactor, which will disrupt the continuous operation of the process or even cause complete drainage of the reactor. For products which used hexene as comonomer or in the eye, the dew point of the recycled material considerably limited the balancing rate.

The basic limitation of the reaction rate in the reactor from fl ^ de ^ ym deposits results from the speed with which heat can be removed from the polymerization sphere. Although in many important respects they differ from the reaction systems in the fluddanny bed, the same problems of thermal restrictions in / They also run in other types of systems that carry out reactions, such as systems for conducting the reaction with stirring, as well as to some extent - systems for conducting the reaction in suspension.

In the description of jpatentwwm St. Zjedn · Amsryki nr -3 256 263, heat removal in the reaction mixing system is carried out by compressing recycled gases and expanding them when re-entering the reactor ·

Other mixing reaction systems using a foot mixer provide some additional cooling at wYⁿInjection liquid on top of the bed, see, for example, the patent specifications St · United · Nos. 3 ^ ιοΖΗ No. 3 254 070, 3 300 457 and 3 652 527 ·

In U.S. Patent Nos. 3,966,083, 3,977,0611 and 3,971,777, the cooling of a mixed bed reactor is assisted by injecting liquid on top of the bed.

In the description of patents St · Zarod · Antiques No. 4 012 573 it is described that the gases withdrawn from the mixed-bed reactor are liquefied in the form of a liquid and recycled in liquid form to the mixed reactor, where the liquid is introduced in the desired way in contact with the polymer in the mixture bed ·

Mitsubishi Petrochemical Co · proposed the use of liquids or liquefied liquids for cooling the gas phase of the reactor / Japanese Patent Specification J55 / 045744/80 and -RFN No. 2 139 18 ^ · In both descriptions liquid or liquefied liquids rather, it is introduced into the deposit, rather than entering into a gas and vent gas as in the method. according to Wmlazku · Description - West German Federal Republic No. 2139182 refers to mixed beds rather than fluidized beds · In Japanese description patθntawyi J55 / O45744 / 8O, liquid before flue gas is flushed into a gas state ·

In the case of a fluidized bed reaction system, as opposed to mixing reaction systems using a paw mixer, homogeneous distribution of ^ ηοϋ ^ and catalysts in the upwardly flowing gas stream is necessary to avoid hot spots and the resulting polymer sinters · in reactors with mixed or deficient beds, these problems are eliminated by mechanical mixing · in fluidized bed reactors and the speed of gas flowing through the reactor must be sufficient to maintain the bed in the gas velocity state wniiδ^anaj to maintain the bed in fluidized suspension cannot be achieved under normal conditions by simply injecting the liquid from the bottom of the bed · Thus, the reactor cooling by direct injection of the liquid, proposed in the description of St · United · AiMrics No. 4 012 573, is not an acceptable solution for a fluidized bed reaction system. This requirement is particularly suitable for the polymerization reaction of one or more of the following ^ ^ noi ^^ i ^:

I · olefin type: ethylene, propylene, butene-1, pentene-1, 4-mθeylpθnlθn-1, hexene-1, styrene

II · Type. polar vinyl monomer: vinyl chloride, vinyl acetate, vinyl acrylate, and methyl

III · Type of diene / conjugated and unconjugated /: butadiene, 1,4-hexadiene, isoprene, etnlidθnorbornrn ·

IV · Type acetylene: substituted acetylene such as meeylacetylene

V · Aldehyde type: formaldehyde

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The conventional method for producing resins, in particular polymers made from monomers, in a fluidaCne bed is carried out by passing a gaseous stream containing one or more monomers continuously through a flux bed reactor under conditions allowing the reaction to proceed and in the presence of a catalyst. From the reactor, a gaseous stream containing the unmarkaged gaseous monomer is continuously withdrawn, compressed, cooled and recycled back to the reactor. The product is withdrawn from the reactor and monomer is added to the recycled stream in an amount to make up the correct composition of the reaction mixture. The formation reaction after exerm is exothermic, so it is necessary to maintain the temperature value of the gas stream inside the reactor so that it not only embeds below the degradation temperature of the resin and catalyst, but also below the temperature of melting or sticking of the resin particles extinguished in progress polymerization reaction. This is necessary to prevent reactor blockage due to rapid build-up of polymer sinters that cannot be taken off as a continuous product. It should be taken into account that the amount of polymer that can be w / formed in a given size of fluidized bed reactor over a certain period of time is directly related to the amount of heat that can be. collect from a fluidized bed. A preferred method for producing polymers in a fluidaCyym bed has now been developed, which method is not limited to a particular type of polymerization.

The method of creep of polymers in reactors with a fluidaCnm bed from one or more liquid monomers by continuously passing a gaseous stream through the reactor in the presence of a catalyst under conditions enabling the reaction to take place, the removal of the polymeric product and nirpΓagging liquids, cooling of the transfused liquids and returning them to the reactor together with ais to replace monomers that have polymerised and have been received as a product, according to the invention consists in that part or all of the non-inert fluids are cooled to form a two-phase gas mixture and droplets suspended therein and the two-phase mixture is reintroduced into the reactor. Preferably, the biphasic mixture of gas and the liquid droplets mixed therein are introduced into the reactor at a location below the fluidized bed, and the non-fluid-like fluids are compressed before cooling. The liquid phase of the two-phase mixture is kept suspended in the gas phase until the liquids evaporate or enter the fluidized bed. Preferably, an inert, condensing liquid is added to the biphasic mixture to raise the dew point of the mixture, such as saturated hydrocarbon. In the process according to the invention, the liquid phase of the biphasic mixture is kept below 20%, preferably below 10%, by weight of the total weight of the biphasic mixture, and the flow rate of the biphasic mixture and the ratio of liquid to gas therein is maintained at the level at which the liquid is in suspended in gas until it evaporates or enters the fluidized bed. The two-phase mixture can be divided into at least two separate streams, at least one of which is introduced into the reactor at a location below the fluidahi bed, and one or more of these streams are introduced directly into the fluidized bed, except that the velocity of all gases introduced below the fluidized bed is at least sufficient to support the bed and maintain it in a fluidic state.

In the method according to the drug, a stream of cooled gas below the maximum desired temperature of the bed is continuously introduced into the bed, and at the same time or separately, a liquid stream is introduced into the reactor in such a way that the bed at a level below the maximum desired temperature in the reactor, a substantially homogeneous two-phase mixture of this gas and liquid is introduced. In addition, in the process of the invention, a two-phase gas stream containing liquid or one monomer, with one or more monomers, is continuously introduced into the polymerization zone at an upward flow velocity sufficient to keep these particles suspended and equivalent through the gas, into the polymerization zone continuously is being introduced. polymerization catalyst such that a polymer product is continuously withdrawn from the polymerization zone and that nlepΓZΓrragnwanr is continuously withdrawn from the polymerization zone

148 356 gases, they are compressed and the gases are cooled to a temperature lower than the dew point of these gases ·

In the latter case, the two-phase gas mixture and the liquid droplets suspended therein are also preferably introduced into the reactor at a location below the polymerization zone, and the unreacted liquids are compressed before cooling and an inert, condensing liquid such as saturated hydrocarbon is added to the two-phase mixture. to bear the dew point of this mixture. In this case, the liquid phase of the biphasic mixture is also kept below 20%, preferably 10% by weight, of the total weight of the biphasic mixture.

In the process, the continuous flow rate of the two-phase mixture and the ratio of liquid to gas in it, as mentioned above, remains at the level in which the liquid is in state. Suspended in gas until it evaporates or enters the polymerization zone and a stream of gas flowing upwards is used through a fluidized bed, essentially uniform in composition and permeating through the bed, such that the entire bed is fluidized in a fluidized state and essentially free of dead space, through which gases, which are received as a product of polymerized monommers, pass through are replaced by additional amounts of one or more monomers in liquid or gas form, which are introduced below the polymerization zone and in the same place or near the place of introduction into the two-phase reactor mixtures are introduced into the gas stream and liquid prior to introducing the two-phase mixture into the reactor. This process preferably uses alpha ol ^ mon monomer containing 2-4 carbon atoms, alone or in a mixture with one or more other ionomiΓαm and alpha olefins containing 2-8 carbon atoms. Thus, it continuously introduces into a bed containing m ^ noi ^ ^, essentially taking a homogeneous mixture of gas and liquid.

In the blaze process, the recycle gas stream is intentionally cooled to a temperature below the roay temperature of the recycle gas stream so as to produce a two-phase gas and liquid mixture in such conditions that the liquid phase of this mixture will remain roofed in the gas phase of this mixture at least from the w&gt; r ° point of entry into the bottom bed reactor until evaporation or entry into the fliridation bed. By using the method according to the invention, a significant increase in volume per unit of time and volume is obtained, with little or no change in the properties or quality of the product. When carrying out this method as described below, the entire process runs continuously and smoothly. without technical difficulties. In some cases, it may be desirable to increase the dew point of the recycle gas stream to further increase heat dissipation. The dew point temperature of the recycle gas stream can be increased by: increasing the operating pressure of the reaction system; or increasing the concentration of condensing liquids in the recycle stream; i / Hub reduces the concentration of non-condensable gases in the recycle stream. In one embodiment of the method of the invention, the dew point of the recycle stream can be increased by adding to the recycle stream of condensation fluid, inert to the catalyst, reaction substrates and polymerization reaction products. This fluid can be introduced into the recycle stream vases with fluid to make up the ml or also by other means or at any point in the system. Examples of such fluids are saturated hydrocarbons such as butanes, pentanes or hexanes.

Restrictions as to the extent to which the recycle gas stream can be cooled below its pace of dew time enters with the replacement that the gas-liquid ratio must be maintained at a level sufficient to maintain the liquid gas of this two-phase fluid mixture in suspended state until the liquid evaporates. It is also necessary that the velocity of the upward fluid stream is sufficient to keep the fluidized bed suspended. Although it can be accepted as a general rule that the liquid content of a two-phase recycled stream may be quite high, the amount of liquefied liquid contained in the gas phase should not exceed about 20% by weight, and preferably should not exceed about 10% by weight ch, always with the proviso that the speed of the two-phase recirculated stream is sufficient in the eye, to keep the liquid phase in suspension in the gas and to hold the fluidized bed under the reactor

The point of introduction of the two-phase recycle stream should be below the fluidized bed / polymerization zone / to ensure homogeneity of the upwardly flowing gas stream and to keep the bed suspended · The recirculated stream containing suspended liquid droplets is introduced into the reactor at a point in the lower reactor area and most preferably at the very bottom of the reactor, to ensure homogeneity of the fluid flowing upwards through the fluidized bed * To prevent near-entry point of recycled gas, areas with low gas velocity, a partition or similar solutions can be used to keep solid particles and liquid droplets suspended flowing up the recycle stream. Although this procedure does not have significant advantages, the two-phase recirculated stream can be divided into two or more separate streams, one or more of which can be introduced directly into the polymerization zone, with the proviso that a smelting gas velocity below and within bed to hold the suspended bed. In all cases, the composition of the gas stream is kept homogeneous and the stream flows in such a way that no dead spaces occur in the bed in which non-removable solids can form.

It is possible to produce a two-phase stream of fluids in the reactor at the injection point by separately injecting gas and liquid under such conditions that will allow the formation of a two-phase stream. Operation in such a way does not entail any advantages, due to the additional and unnecessary cost and trouble arising from the gas phase separation and liquid after cooling. It may be desirable, however, to introduce supplementary amounts of monomer into the reactor in this way. · In the process of the invention, it is envisaged to inject liquid or gaseous supplementary monomer at the point of introduction of the two-phase recycle stream, or elsewhere in the reactor or into the recycle stream.

Method sets according to^on The iron is not limited to the use of polyolefin resins. The method according to the invention can be applied to any process of exothermic polymerization carried out in a fluidized bed suspended in the use of a gas phase. Advantages of the method according to the invention generally increase in direct processes due to the proximity of the recycle dew temperature and reaction temperature inside the fluidized bed. For obvious reasons, the process according to the invention cannot be used in a reaction lead system in which the reaction temperature in the fluldate bed is below the dew point of the recycle gas stream. The ability to process the mill for producing any given polymer can be determined using the following formula:

^χ = P_ · ^ γχπ _________ \ ______ ^Gmass * ^CPGas ^^Trxn " ^Tlimit/

P - desired polymerization rate; without wCkOozy ^ tyaaniα of the method according to the invention limited to rates giving an X value below 1.0 ·

H_rxn - heat of polymerization of the specific polymer produced.

G - mass flow rate of the recycle stream; the minimum value is limited by the need for proper fluidization and mixing of the material in the bed, and the maximum value is due to entrainment of solid particles. The specific minimum and maximum values ​​depend on more than one action known in the world.

CPgas thermal capacity of the recycled plant.

Τ_ρχη - reaction zone temperature / fluidized bed /; the maximum value depends on tern6

148 Due to the stickiness of the polymer particles under the pressure of the recycled stream and / or the efficiency of the catalyst, the minimum value depends on the efficiency of the catalyst.

, I.e. the minimum temperature of the recycle stream entering the reaction zone, determined in accordance with the restrictions adopted prior to the introduction of the method of the invention. This temperature is the dew point of the recycle atr or limits the possibility of cooling the heat exchange zone, whichever is the greater. If it is the dew point temperature of the recycle stream, the method according to the invention is carried out by simply cooling this stream to a temperature below the dew point temperature. If, on the other hand, the value is determined by the heat exchange zone, then the method according to the invention is carried out by adding a condensing liquid to raise the dewatering temperature of the recycle stream to a temperature above the limit of the possibility of cooling the zone in^mand^any heat ·

K. only the value of X is greater than 1, the use of the method according to the invention will provide benefits and im^Z8J the value of X increases, the greater the benefits that can be achieved by using the method according to the invention. The attached drawing shows a fluidized bed reaction system that is particularly suitable for the production of polyol resin using the method of the invention. As can be seen from the figure, reactor 10 consists of reaction zone 12 and velocity-reduced zone 14.

Generally speaking, the ratio is^juiceThe diameter to the diameter of the reaction zone may range from about 2.7: 1 to about 4.6: 1. This range may vary from higher or lower indium pile and depends on the desired capacity. The cross-sectional area of ​​the velocity zone 14 is typically 2.6 to 2.8 times the cross-sectional area of ​​the reaction zone 12. The reaction zone 12 houses a bed of growing polymer particles, already formed polymer particles and a smaller number of catalyst particles, solved by a continuous flow of polymerized and monyyking gaseous components, flowing through the reaction zone in the form of supplementary amounts of feedstock and recycled fluid stream.

To maintain a stable fluidized bed, the velocity of gas flowing through this bed, calculated on the cross-section of the empty reactor, must exceed the minimum flow removed for fluidization, preferably it must be at least 0.06 m / s from the minimum flow. The gas velocity, which is usually calculated for the cross section of the empty reactor, does not exceed 1.5 m / s, and a speed not exceeding 0.75 m / s is usually sufficient.

It is essential that the bed always contains particles to prevent the formation of low scale hot spots and to capture and distribute catalyst particles in the reaction zone. At start-up, before switching on the gas flow, the reactor is usually charged, providing the basic charge of the crumbled polymer particles. Such particles may be identical in type to the polymer to be produced, or be different from it. When they are different, they are received as the first product together with the particles of the desired polymer formed. Finally, the fluidized bed of desired polymer particles replaces the starter bed. The partially or fully activated precursor compound and / or catalyst used in the fluidized bed is preferably stored in tank 16 under a gas inert to the stored material, such as nitrogen or argon.

Fluidization of the bed is achieved by using a high flow rate of recycled liquid and through the bed, typically on the order of about 50 times the flow rate of the make-up feed supply and the processed raw material. The fluidized bed has the general appearance of a dense mass of individually moving particles formed as a result of gas percolation through the bed. The pressure drop in the bed is equal to or greater slightly than the weight of the bed divided by the cross-sectional area. Z lies therefore from the geonmerli reactor. The liquid supplementing the losses due to the reaction is led to the bed in point 18. The composition of the supplementary stream is determined by means of a gas analyzer 21. Arnai '

148 The gas embolism determines the composition of the recycle stream and the make-up stream composition is adjusted accordingly to maintain a substantially constant gas composition in the reaction zone. Gas analyzer used in the system This is a conventional gas analyzer, operating in a conventional manner and indicating the composition of the recycle stream, and adapted to regulate the amount of feedstock entering the reactor; it is commercially available from many different suppliers. Usually, the gas analyzer 21 can be positioned so that it receives gas from a point between the speed reduction zone 14 and the heat gingerbread 24.

To ensure full fluidization, the recycle stream and, where desired, also a portion of the make-up stream is recycled via recycle line 22 to the reactor at 26 · below the bed. To facilitate fluidization of the bed, a perforated gas distribution plate 28 may preferably be above the point of stream entry. When passing through the bed, the recycle stream absorbs the heat of reaction produced by the polymerization reaction. The part of the fluidizing bed that has not reacted in the bed creates a recycle stream which is withdrawn from the polymerization zone, preferably by passing it to the zone of acceleration of speed 14 above the bed, where the gas entrained particles have the possibility of falling back into the bed.

In turn, the recycle stream is compressed in compressor 30 and then passed through a heat exchange zone in which the heat of reaction will be returned to it before returning to the bed. The heat recovery zone is a typical heat exchanger 24 which can be horizontal or vertical. The recycle stream is fed back into the reactor at its base 26 and into the fluidized bed through a perforated gas distribution plate 28. A gas deflector 32 is preferably installed at the inlet of the reactor to prevent settling and agglomeration into the solid mass of polymer particles contained.

The bed temperature is controlled under steady state conditions by continuously receiving heat of reaction. There is no noticeable temperature gradient in the upper part of the bed, but it will occur at the bottom of the bed, in a layer about 15 to 30 cm thick, between the temperature of the inlet fluid and the rest of the bed. Good gas distribution plays an important role in the operation of the reactor. The fluid bed contains growing and fortified already shredded polymer particles and catalyst particles.

Because the polymer particles are hot and possibly active, they must not be allowed to settle, because if the stationary pmsy is allowed to occur, the active catalyst contained therein may continue to react and cause the polymer to melt. It is therefore important to diffuse recycle fluid through the bed at a rate sufficient to maintain fluidization throughout the entire bed.

To achieve good gas distribution, a gas distribution plate 28 is preferably used, it may be a sieve plate, a plate plate, a perforated plate, an i-tp bell plate. All plate elements may be stationary, or the plate may be of a movable type, as described in the patent description. ym St. Ser. Anpeyki No. 3298792. Regardless of its design, it distributes recycled fluid through the particles at the bottom of the bed to keep the bed in fluidized state, as well as serve to scratch the still bed of resin particles when the reactor is not in operation.

A preferred type of gas distribution plate 28 is a plate made of metal and provided with holes distributed over its entire surface. Otwoirs usually have a diameter of about 13 mm. · Above each hole is a triangular stand angle 36, permanently attached to plate 28. Steel angle angles are used to distribute fluid along the surface of the plate so as to avoid the presence of standing zones of solid particles. In addition, they prevent the resin from flowing through these holes when the bed settles. There may also be any fluid inert to the catalyst and reactants in the recycle stream. If used, the activator is preferably added to the reaction system downstream of the heat exchanger 24, so that the activator can be introduced into the circulation system from the dosing device 38 through line 40.

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The basic off-set for conducting the process in a Jeat fluidized bed reactor is to keep the temperature below the sintering temperature of the polymer particles to prevent sintering. Sintering temperature is a function of resin density. In general, for example, low density polyethylene has a low sintering temperature, while high density polyethylene has^ssintering temperature. . Thus, for example, to boil ethylene copolymers having a density of about^0,91 g / cm &amp; lt; ^{to Fr.}Circles^about 0.95 g / cm ^ g -the temperature^s about^d about 75 ° C ^dabout 95 ° C, while for balancing ethylene copolymers or homopolymers having a density of olcoło ^0,95 g / cm &amp; lt; ^d° approx ^{0.97 g}/ cm ^ applies p^ut temperature ^ from around 1⁰⁰° C ^doo^kabout 115 ° C. The fluid bed reactor can operate at pressures up to about 6,897 MP, and in the production of polyol filter resins it preferably works at a pressure from about 689.7 kPa to about 2.414 Ma, while work at your pressures in these ranges promotes heat , because the increase in pressure also increases the heat capacity of the gas volume unit.

Partially or fully activated precursor compound and / or catalyst (hereinafter collectively referred to as catalyst) is injected into the bed at a speed equal to their wear at point 42, which is located above the gas distribution plate-28. Preferably, the catalyst is injected at a point in the bed where the polymer particles mix well. · Injection of the catalyst at a point above the distribution plate is an important element ensuring the satisfactory performance of the fluidized bed polymerization reactor. Because the catalysts are still active, injection of the catalyst into the area below the gas distribution plate can cause the initiation of the polymerization process and finally clogging of the plate, while injection into the ore and bottom deposit helps to distribute the catalyst throughout the mass of the bed and helps to prevent the formation of clogged places o ^ Sokm concentration of the catalyst, which may cause eradication of hot spots. In turn, injection of the cable into the reactor above the bed may cause excessive transfer of the catalyst to the circulation line, where polymerization may begin, which in turn may result in blockage of this line and heat mimicry.

Ktallzator can be injected into the reactor using various techniques. It is, however, preferred to continuously feed the catalyst into the reactor using a catalyst dispenser such as, for example, St. Pat. Ser. Antiques No. 3779712. The catalyst is preferably introduced into the reactor at a point at a distance corresponding to 20 to 40% of the reactor diameter from the reactor wall, and at a corresponding height from about 5 to about 30% of the bed height. For^rThe inertia of the catalyst to the bed is preferably a catalyst inert gas such as nitrogen or argon. The speed of balancing the polymer in the bed depends on the injection rate of the catalyst and on the concentration of monomens (s) in the recycle stream. The rate of production is controlled by simply adjusting the rate of catalyst injection.

Because any change in the rate of catalyst injection will change the reaction rate and so on. by the same rate of reaction heat production, the temperature of the recycle stream fed into the reactor is adjusted to adapt to the change in the rate of heat balancing, ensuring that the temperature remains constant in the bed. Complete equipment for both the fluidized bed and the recirculated gas cooling system is useful for uploading a specific temperature change in the bed so as to enable the operator or a conventional automatic control system to resist regulating the temperature of the recycle gas. gas.

For a given set of operating conditions, the fluidized bed is maintained at a substantially constant height by receiving a portion of the bed as a product at the rate of particle formation of the polymer product. Since the rate of heat production is directly related to the rate of product formation, the measurement of the temperature of the fluid in the reactor is measured / the difference between the temperature of the inlet fluid and the temperature of the fluid

148 356 at the outlet / indicates the rate of polymer particle formation at a constant fluid flow rate if no evaporating liquid in the reactor enters the fluid at the inlet. When discharging the polymer product particles from reactor 10, it is desirable and advantageous to separate the fluid from the product and recycle this fluid 22. Numerous methods are known in the art for discharging this task, one preferred arrangement is shown in the drawing. Thus, fluid and product leave the reactor 1Q at 44 and pass into the product discharge tank 46 through valve 48, which when open should create a minimum flow restriction such as, for example, a ball valve. Above and below the product discharge tank 46 there are conventional valves 50, 52, the latter being used to ensure the passage of the product to the product expansion tank 54. The product expansion tank 54 has a venting device, shown as line 56 and a gas supply device, shown as cable 58. At the base of the product expansion tank 54 there is a discharge valve 60, which in the open position is used to transfer the product to the warehouse and then on route 68 to circuit • circuit 22.

With a typical operating regime, valve 48 is open and valves 50, 52 are closed. Product and fluid enters the product discharge tank 46. The valve 48 closes and the product is allowed to settle in the product discharge tank 46. Then the valve 50 opens, allowing fluid to flow from the product discharge tank 46 to the collector, 62, from which it is continuously compressed and sent back to circulation line 22. The valve 50 then closes and the valve 52 opens, so that the product collected in the product discharge tank 46 flows into the product expansion tank 54, then the valve 52 closes. The product is purged with an inert gas, preferably nitrogen, which is introduced it goes to the product expansion tank 54 via conduit 58 and is vented into the atmosphere via conduit 56. Finally, the product is discharged from the product expansion tank 54 through valve 60 and sent to a warehouse via line 20

Certain adjustment sequences during valve operation are carried out using conventional, programmable known control devices. The valves can be kept clean without accumulating in them agglomerated polymer particles by installing devices to direct the gas flow periodically through these valves and directed back to the reactor.

Alternatively, another product discharge system may be used, comprising at least one / parallel / pair of tanks, which includes a sludge tank and an intermediate tank connected in series and having a separate gas phase conduit, led from the top of the sludge tank to a point in the reactor nearby top of the fluidized bed. This αltθΓnalwrnl product discharge system eliminates the need to use the recompression line 64, 66, 68 shown in the system drawing.

The Rector behind the fluidail bed is equipped with an appropriate system &lt;z o.o. / not shown /, to enable the airflow during start-up and infiltration. The reactor does not require mixing and / or wall machining. Circulation line 22 5 components / compressor 30 contained in it, wt 24/24 heat meter, should have smooth surfaces and be free from unnecessary obstacles so as not to disturb the recipe of the recirculated fluid or suspended in it particles · For poleeerói which can be made by the process of the invention, include homopolymers of ethylene, propylene and butene, or copolymers containing more mole percent ethylene, propylene or butene and a lower mole percent of one or more alpha olefins containing from 2 to 8 carbon atoms. Oil alpha containing from 2 to 8 carbon atoms should preferably not contain a branch on any bH carbon higher than the fourth carbon atom. Preferred alpha-oefins containing from 2 to 8 carbon atoms include ethylene, propylene, butene-1, pentene-1 , hexene-1, 4-mθiylżpθntθn-l i, octen-l ·

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For example, ethylene polymers have a melt flow rate above 22. The melt flow rate index is another means of indicating the polymer molecular weight distribution. Thus, for example, the melt flow index / MFR / equal to 22 corresponds to an Mw / Mn value of about 2.7 / determined by gel gel chroparopy /. Ethylene Hornopolymers^pelk^dthey have a density of^d ^ yaw about ^0,958 down to about 0.97² g / cm \ Ethylene copolymers have a density below about ^0,9⁶ g / cm \ G * sto^śethylene copolymer, ^pWHO ^dThe level of melt flow index for this copolymer is regulated in the first row by the amount of the comnner. containing from 3 to 8 carbon atoms, which copolymerizes .silve with ethylene. In the absence of kpoonom, ethylene could polymerize alone to give polymers^po ^^andand^dthick^śÆ ^pthey^fromhey about ^0,96 g / cm ^ · ^Tas^ęc addition: gradually increasing^andc^sch^ęhigher amounts of comonomers to the copolymers results in a gradual decrease in the copolymer density. The amounts of each of the different comonomers containing from 3 to 8 carbon atoms needed to obtain the same result under the same reaction conditions vary from monomer to monomer.

Thus, for the preparation of binary ethylene copolymers of the same density and thus in total melt flow rates, increasing molar amounts of different kpmpnomers would be needed in the order C ^&gt; C ^&gt; C ^&gt; C ^&gt; C? &gt; C_q· With ^^ Γζβηία in the process described here in the fluidized bed, ethylene polymers are granular materials, having a bulk density of about 2^{40 d}at 5^{12 kg}/ m ^ i ^śre^dn^ble size^andsteak rivers^ę0.13 to 1.52 mm · Particle size is important for the ease of fluidization of the polymer particles in the fluidized bed reactor described herein.

The process of the invention envisages a process ensuring an increase in efficiency per unit of time and volume of polymer production in a fluidized bed reactor, using an exothermic pollomerization reaction, consisting in - cooling the recycle stream below its dew point and returning the resulting two-phase fluid stream to the reactor to maintain fluidized bed at the desired temperature of 0 ° dew point of the recycle stream. The cooling capacity of the recycle stream increases both due to the greater temperature difference between the recycled stream and the reactor and the vaporization of the liquefied liquids suspended in the recycled stream.

It was therefore concluded that the hitherto existing limitation of the dew point imposed on the recycle stream was, as shown above, a wrongly imposed limitation. These restrictions were found to be incorrect and should not be applied. The degree of condensation - and thus the increase in the production rate can be further increased by changing the process conditions so as to raise the dew point of the recycled stream. It has been found that the degree of condensation of the liquid in the recycle stream can be up to about 20% by weight of the liquid, preferably up to about 10% by weight of the liquid. This degree of condensation is achieved by maintaining the temperature at the outlet of the cycle zone poured out heat so as to cause the desired degree of cooling below the dew point of this mixture.

Example 1 In the embodiment of the process according to the invention, the above-described system for conducting the gas-phase reaction in a fluidized bed, with partially liquefied recycled recycling, was used to produce a copolymer with the composition hexm-1 / / propylene / ethylene, in the following conditions: for the circulation of the stream / mole percent /: nitrogen - 34.7; ethylene - 38.1; ethane - 8.9; propylene - 5.1; hexene-1 - 4.8; hydrogen - 7.3; methane - 0.1. Dewort pressure of the recycle stream: 57.8 ° C / under pressure prevailing in meters of heat /. Temperature at the gas inlet to the reactor: 48 ° C. Liquid gas content: 4.6% by weight.

Telkizer: kn ^ exex, which consists of tetrahydrofuran, magnesium chloride and titanium chloride reduced with dieylgluu chloride / sPO3 ^ molosium chloride of two ^ yllglin chloride to tetrahydroίUlΓβlu is 0.4 / and triple-hθxyPogllemol-sulfinyl chloride tetrahydrofuran is 0.4 /, applied to silicon dioxide, treated with Third Gogrel · reactor springboard: 88 ° C; reactor pressure: 1,862 Me; p ^ ęd148 356 gas in the fluidized bed calculated on the cross section of the empty reactor: 0.6 m / s; bed height: 11.28 m; bed diameter: 2.44 m; cost per time and volume unit: 81.7 kg / m ^ h^; w3kaó.ni^knorth^nięiia resin: ^1,0 dg / min ·; density; from^svdc^s: ^0,9¹⁸ g / cm &amp; lt;^; acts wator: trójetyloglin ·

Example II. In this example, the reaction was carried out under essentially identical operating conditions as in Example 1, with only changes in the cooling of the recycle stream and the catalyst injection rate. Composition of recycled stream / mole percent /: nitrogen - 36.5; ethylene - 38.2; ethane 11.2; propylene - 5.0; hexa -1 - 4.1; hydrogen - 4.8; methane - not detected. Temperature of the recycle dew stream: 53.2 ° C / under pressure prevailing in the heat transfer medium /; reactor gas inlet temperature: 60.6 ° C; liquid content in the recycle gas: zero; reactor temperature: 87.1 ° C; reactor pressure: 1,862 MPa; gas velocity in the Hczon fluidized bed per empty reactor section: 0.6 m / s; bed height: 11.28 m; bed diameter: 2.44 m; capacity per unit of time and volume: 32 kg / mh; resin flow rate: 1.0 dag / min; resin density; 0.918 g / cm, activator? triethylaluminum.

• It should be emphasized here that conducting the process below the temperature of the dew stream of the recycle stream, as in Example 1, resulted in an increase in the output per unit of time and volume / kg of resin produced in the reactor per m of bed and hour / , which was approximately 2.5 times higher than the yield obtained without the use of the liquid phase in the recycle stream as in this example II.

Example ΠΙ. In the following example, butene-1 was used as the other alpha olefin monomer instead of propylene and hexene-1 and the following conditions were used: Composition of the recycle stream (percentages of nolowols): hydrogen - 6.3; ethylene - 57.8; butene-1 26.7; inert gases - 9.2; temperature ^ dew of recycle stream stream: 49.7 ° C / under pressure prevailing in the heat exchanger, /; temperature in the gas inlet to the reactor: 47.2 ° C; liquid gas content in the circulation gas: 1.2% by weight; catalysis: comlex, which consists of trtahahirofUra-, magnesium chloride and titanium chloride reduced only with trin-hexylglomer / molar ratio of tri-n-hexylglycine to tetrahydrofuran is 0.7 /, treated with silicon dioxide treated with triethylgll! Reactor temperature: 87.5 ° C; reactor pressure: 1.855 MPa; gas velocity in the fluidized bed divided into an empty reactor section: 0.6 m / s; bed height: 11.28 m; bed diameter: 2.44 m; yield per unit of time and volume: 99.3 kg / mh ;, melt flow rate^yc^s: 1,⁰ ^^^^{g /}mLN^; densely^SC from^swic^s: ^0,9^{18 g}j^/cm &amp; lt;^; and^ctscroze: ^troses ^ 1 ^ 11 Preface IV. In this example, the reaction was carried out in verbs similar to those used in Example 3, without condensed liquid in the recycle gas stream. Composition of the recycle stream / molar processes /: hydrogen - 4.5; ethylene - 59.3; butene-1 - 26.7; inert gases - 9.5 · Temperature of recycle dew stream: 44, 1 ° C. under pressure prevailing in the heat exchanger /; reactor gas inlet temperature: 56 ° C; liquid content of the recycle gas: zero; catalyst: a complex consisting of tetrahydrofuran, magnesium chloride and titanium chloride reduced only with tri-n-hexylalgler / molar ratio of tri-n-hexyaluminum to tetrahydrophylLra is 0.7 /, treated with dihydrate treated with dihydrate tró jetz / 1aluminem · Reactor temperature: 83.7 ° C; reactor pressure: 1.827 MPa; gas velocity in the fluidized bed connected to the cross section of the empty reactor: 0.76 m / s; deposit depth: 11.43 m; diameter

About the deposit: 2.44 m; capacity per unit of time and volume: 59.3 kg / mh; speed indicator^pL^millut^cand^and from^swic^s: 1,0 ^gEsto^śż^swic^s: ^0,918 g / cm &amp; lt;^; and^ctswator: tr^about je ^ loglln ·

Example V - X. For six further examples in tabular form, further agreements were made regarding the implementation of the slag process using different condensation degrees of recycled streams to improve bed cooling in the limiting and after the hθkser-l / -butθnll / etzle sets -, ethyl- / erlpylene; ethylene / butene-1, enene-1-ethyl-as well as using isler-t-t As an inert fluid, ldeoweθdnil was in the process of polymerization of the butylene / ethyl-and

148 356 ι

AND

AND

AND

AND

AND

AND

AND

AND

AND

AND

AND

AND

AND

Example No.

Product

AND

AND

AND

AND

AND

And ί

And

AND

AND

AND

AND

AND

AND

Composition of the recycle stream / mole percent /:

nitrogen ethylene ethane propylene propane butene-1 butane * pentene-1 isopentane hexene-1 hydrogen methane

Temperature of recycled dew stream / C /

TθαperatuΓa in the world for the reactor / ° C /

Liquid content in the circulation gas /% weggo '^ / TθmperatuΓa reactor / ° C /

Pressure in the reactor / MPa /

Fluid bed gas velocity. calculated on the cross section of the empty reactor / m / s / Deposit height / p /

Output per unit of time and volume. /^kg/ P-h /

<td></td><td> ·—--1-</td><td></td><td></td><td></td><td> · —</td>

<td>V</td><td> 1 1 1</td><td>VI</td><td> 1 1</td><td>VII</td><td></td>

<td>copolymer</td><td rowspan="2">1 1 1 and 1 1 |</td><td>copolymer</td><td>ί</td><td>copolymer</td><td></td>

<td>C6 / C4 / C₂</td><td>V^c3</td><td>and 1 1 1</td><td>C2 / C₄</td><td></td>

<td> 34,7</td><td>AND</td><td> 17,4</td><td> 1 1 1</td><td> 43,5</td><td></td>

<td> 38,1</td><td> 1 1</td><td> 0,64</td><td rowspan="2">and</td><td> 0,25</td><td></td>

<td> 6,9</td><td> 1 |</td><td> -</td><td> -</td><td></td>

<td></td><td rowspan="2"> 1 1</td><td> 63,5</td><td rowspan="2"> 1 1</td><td> -</td><td>⁵</td>

<td> -</td><td> 16,5</td><td> -</td><td> 1</td>

<td> 5,1</td><td> 1</td><td> -</td><td> 1 1</td><td> 50,0</td><td></td>

<td></td><td rowspan="2">^ί 1</td><td> - .</td><td> 1 1</td><td> 5,0</td><td></td>

<td> —</td><td> . —</td><td rowspan="2"> 1 1</td><td> —</td><td></td>

<td> 1,0</td><td rowspan="2"> 1 1</td><td> 1,0</td><td> 0,5</td><td></td>

<td> 4,8</td><td></td><td rowspan="2"> 1 1</td><td></td><td rowspan="2"></td>

<td> 7,3</td><td> 1</td><td> 0,95</td><td> 0,75</td>

<td> 0,1</td><td>1 AND</td><td> —</td><td>1 1 AND</td><td> -</td><td></td>

<td> 63,0</td><td> 1 1 1 1</td><td> 44,4</td><td> 1 1 1</td><td> 44,0</td><td></td>

<td> 54,3</td><td>and 1 1 1</td><td> 43,5</td><td>and 1 and</td><td> 41,6</td><td></td>

<td> 4,8</td><td rowspan="2">1 1 AND 1 1</td><td> 4,2</td><td> 1</td><td> 8,8</td><td></td>

<td> 88</td><td> 60</td><td>l and |</td><td> 50</td><td></td>

<td> 1,862</td><td> 1 1 1 1 1</td><td> 1,862</td><td> 1 1 1 1 1 1</td><td> 0,835</td><td></td>

<td></td><td rowspan="2">and 1</td><td></td><td> 1</td><td></td><td></td>

<td> 0,6</td><td> 0,52</td><td rowspan="2">1 ! and</td><td> 0,6</td><td></td>

<td> 11,28</td><td>1 l</td><td> 11,28</td><td> 11,28</td><td></td>

<td></td><td>AND 1</td><td></td><td> / 1</td><td></td><td></td>

<td> 86,1</td><td> 1 1 1 1</td><td> 105,7</td><td> 1 1 1 1 1</td><td> 64,1</td><td>----and</td>

x Under the pressure prevailing in the heat pump and Example No.

VIII

IX

And Product Composition of recycled stream J / mole percent /:

and nitrogen, ethylene, and tan and propylene

J propane and butene-1

Jbutan pentene-1

And isopentane! hexene-1} hydrogen and methane j Temperature of recycle dew stream S. / ° C / *

Temperature inlet to! reactor / ° C / k_____________________

Γ

AND

AND

AND

AND

And

AND

AND ^and

AND

AND

AND

AND

AND

AND

AND

AND

AND

copolymer

C₅/ C₂

40,7

35,0

9,0

10,5

3,8

1,0

53,7

42,5

Copolymer c₄/ c₂

15,7

38,6

3,0

17,7

2,3

14?2

6?2

2,3.

74,4

65.9 and

--II

AND

HoelPeeei.pθr

C

37,5

35,0

5,0

10,5

11,0

1,0

47,4

34.0 table continued on page 13

<td>continuation of the table</td><td> —1»--</td><td colspan="3"> 148 356</td><td> 13 ———1</td>

<td>1 ί Zawirto^youc^zy in gas f sbiβgawym /%</td><td> 1 1 1 1 1</td><td>θ 4</td><td> 11,5</td><td> 1 1 1 5 10,5</td><td> 1</td>

<td>and J Τθι ^ θ / 3 reactor / C /</td><td> 1 1</td><td> 88</td><td> 88</td><td>J 110</td><td></td>

<td>1 Pressure in the reactor / MPa /</td><td>V 1 |</td><td> 1,862</td><td> 1,862</td><td> ! 1,862 1</td><td></td>

<td>Gas velocity in fluidized bed</td><td> |</td><td></td><td></td><td> 1 1</td><td></td>

<td>calculated by cross-section</td><td>t</td><td></td><td></td><td> 1</td><td></td>

<td>empty reactor / m / s /</td><td> 1 1 1</td><td> 0,6</td><td> 0,6</td><td> ! 0,6</td><td>and</td>

<td>Bed height / m /</td><td>L l</td><td> 11,28</td><td> 11,28</td><td>and 11^,28</td><td></td>

<td>Productivity per unit of time</td><td> 1</td><td colspan="2"> 1</td><td> 1 1 1</td><td rowspan="2">and</td>

<td>and covered ^ !. / Kg / m? H /</td><td>1 and</td><td> 128,2</td><td> 112,1</td><td> ! 171,4</td>

&lt;Under pressure prevailing in m me heat Miku ·

The improvement in performance per unit of time and volume achieved in the method of the invention is the result of the increased cooling capacity of the recycle stream. This increased cooling capacity results both from the larger temperature difference between the recycled stream entering and the bed temperature, and from the evaporation of the condensed liquid suspended in the recycle stream. Improved cooling was achieved not only as a result of evaporation of the suspended liquid introduced, but also as a result of an overall reduction in the temperature of both the liquid and gas phases of the recycle stream compared to previously known methods of fluidized bed reactors.

Although the method according to the invention can be used to increase production volumes from existing and new industrial reactors, this invention also creates the opportunity to reduce the costs of equipment in new reactors. Thus, installations designed in accordance with the current state of the art technology for the production of certain ethylene copolymers, in which alpha olefin monomer, hexane-1 is used, they must have larger diameter reactors, due to lower performance per unit of time and volume. Since the method according to the invention increases the yield per unit of time and volume of the products containing hexene-1, the boiling capacity of conventional copoly m] e] ^ &lt;^ into butene-1 / ethylene, then The process according to the invention eliminates the additional cost associated with the need to use a larger diameter reactor as a result investment and operating costs of the recycle gas compressor are reduced ·

The advantages of the process according to the invention compared to other heat removal methods that utilize condensed liquids include the simplicity of the invention process, good liquid distribution, maximum heat dissipation and a homogeneous composition of the gas stream in the polymerization zone, resulting from the two-phase introduction of the recycle stream in the lower reactor regions. There is no need for devices for collecting, separating or injecting liquids, and, moreover, these liquids are dispersed in the stream penetrating the fluidized bed throughout its entire cross-section surface, preventing the occurrence of temperature gradients and high local liquid concentrations around the injection devices.