MXPA98005503A - Olefi polymerization process - Google Patents

Abstract

The present invention relates to: A polymerization process characterized in that it comprises: polymerizing, in a loop reaction zone, at least one olefin monomer in a liquid diluent to produce a fluid suspension comprising liquid diluent and solid olefin polymer particles maintaining a concentration of the solid olefin polymer particles in the suspension in the area of more than 40 weight percent based on the weight of the polymer particles and the weight of the liquid diluent and continuously removing a suspension having a increase in concentration of solids compared to the suspension in the zone, the suspension thus removed withdrawn liquid diluent and removed solid polymer particles as an intermediate product of the process

Description

--_.

OLEFINES POLYMERIZATION PROCESS BACKGROUND OF THE INVENTION The present invention relates to the polymerization of olefin monomers in a liquid diluent. Addition polymerizations are frequently carried out in a liquid which is a solvent for the resulting polymer. When high-density (linear) ethylene polymers became commercially available in the first place in the 1950s, this was the method used. It was soon discovered that a more efficient way to produce such polymers was to carry out the polymerization under conditions of a suspension. More specifically, the polymerization technique of choice became a continuous suspension polymerization in a closed loop reactor with the product being removed by means of legs or legs of sedimentation which are operated on a principle of operation in batches to recover the product. This technique has enjoyed international success, with billions of pounds of polymers of Rßf.027806 ethylene that have been produced annually. With this success has come the desirability of building a smaller number of large reactors as opposed to a larger number of small reactors for a given capacity of a plant. The legs or legs of sedimentation, however, present two problems. First, they represent the imposition of a "batch" technique on a basic continuous process. Each time the leg or leg of sedimentation reaches the stage where the same "discharge" or "drops" the accumulated polymer suspension, they cause interference with the flow of the suspension in the upstream reactor and the recovery system downstream. Also the essential valve mechanism to completely seal periodically the legs or legs of sedimentation from the upstream reactor and the downstream recovery system, require maintenance due to the difficulty in maintaining an airtight seal with the diameter valves large enough to seal the legs or legs. Secondly, when the reactors have become larger, the legs or legs of sedimentation have presented logistical problems. If a pipe diameter is doubled, the reactor volume has to be increased up to four times. However, because of the valve mechanisms involved, the size of the legs or legs of sedimentation can not be easily increased further. Hence, the number of legs or legs required begins to exceed the available physical space. Despite these limitations, the legs or legs of sedimentation have continued to be employed where the olefin polymers are formed as a suspension in a liquid diluent. This is because, unlike the polymerizations of the volumetric suspension (ie, where the monomer is the diluent) where the concentrations of solids better than 60% are routinely obtained, the suspensions of a polymer of Olefins in a diluent are generally limited to no more than 37 to 40 weight percent solids. Hence, it has been believed that the legs or legs of sedimentation will be necessary to give a product of final suspension at the exit of the legs or legs of sedimentation, greater than 37-40 percent. This is because, as the name implies, sedimentation occurs in the legs or legs to increase the concentration of solids in the suspension finally recovered as the suspension of the product. Another factor that affects the practical, maximum solids contents of the reactor is the circulation speed, with a higher speed for a given reactor diameter that allows a higher quantity of solids since a limiting factor in the operation is the fouling of the reactor due to the accumulation of the polymer in the reactor. It could be particularly desirable to operate a polymerization process of olefins in suspension in a diluent in a reaction zone greater than 113., 550 liters (30,000 gallons). According to the present invention there is provided a process for polymerizing the olefins, which comprises: polymerizing, in a closed loop reaction zone, at least one olefin monomer in a liquid diluent to produce a fluid suspension comprising a liquid diluent and polymeric particles of solid olefins; maintaining a concentration of the polymer particles of solid olefins in the suspension in said zone of more than 40 weight percent based on the weight of the polymeric particles and on the weight of the liquid diluent, and for at least one portion of run of production that continuously extracts the suspension, which comprises the extraction of the liquid diluent and the extraction of the solid polymer particles as an intermediate product of the process.

In one embodiment the suspension is continuously extracted substantially from beginning to end of a partial run. In another embodiment during the production run, a step of continuously extracting the suspension is alternated with a step comprising: extracting the suspension, allowing the suspension to settle in at least one settling zone and thereafter extracting a batch of the suspension thus sedimented from the sedimentation zone as an intermediate product of the process, and after that close the sedimentation zone. In accordance with another aspect of this invention, a closed circuit reactor olefin polymerization process is carried out operating at a higher flow rate for a given diameter of the reactor pipe. According to another aspect of this invention, a closed circuit polymerization apparatus is provided having an elongated hollow fitting at one end underneath one of the longitudinal segments of the closed circuit, the hollow fitting is in direct fluid communication with a line of hot instant vaporization and therefore is adapted for the continuous removal of the suspension of the product.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, which form a part of the invention, Figure 1 is a schematic perspective view of a polymer recovery system and closed loop reactor; Figure 2 is a cross-section along line 2-2 of Figure 1 showing a continuous take-up fitting; Figure 3 is a cross-sectional view along line 3-3 of Figure 2 showing a gate valve arrangement in the continuous intake assembly; Figure 4 is a cross-sectional view of a tangential location for the continuous take-up assembly; Figure 5 is a side view of a closed loop reactor elbow showing the assemblies of both continuous intake and the settling leg; Figure 6 is a cross-sectional view along the line 6-ß of Figure 5, showing the orientation of two of the continuous take-up assemblies; Figure 7 is a side view showing another orientation for the continuous take-up assembly; Figure 8 is a cross-sectional view of the drive mechanism; Figure 9 is a schematic view showing another configuration for closed circuits where the upper segments 14a are half circles of 180 degrees and where the vertical segments are at least twice as long as the horizontal segments and Figure 10 is a schematic view showing the longest axis placed horizontally.

DETAILED DESCRIPTION OF THE INVENTION Surprisingly, it has been found that the continuous taking of the product suspension in an olefin polymerization reaction carried out in a closed-loop reactor in the presence of an inert diluent, allows the operation of the reactor at a much higher concentration of solids. elevated The commercial production of the ethylene polymers predominantly in the isobutane diluent, has been limited to a maximum concentration of solids in the reactor of 37-40 weight percent. However, continuous intake has been found to allow significant increases in the concentration of solids. In addition, the continuous intake itself causes some additional increase in the content of the solids when compared to the content in the reactor from which the product is taken because of the placement of the continuous intake fitting which selectively removes a suspension of a stratum where solids are more concentrated. Hence, concentrations greater than 40 weight percent are possible in accordance with this invention.

From beginning to end of this application, the weight of the catalyst is not considered since the productivity, particularly with the chromium oxide on silica, it is extremely high. Also surprisingly, it has been found that a more aggressive circulation (with its concomitant highest solids concentration) can be employed. Actually, more aggressive circulation in combination with continuous intake allows a solids concentration greater than 50 percent by weight to be removed from the reactor by continuous intake. For example, continuous intake can easily allow it to operate at 5-6 percentage points higher; that is, the reactor can be adjusted to easily raise the solids by 10 percent; and the more aggressive circulation can easily add another 7-9 points to the percentage, which puts the reactor above 50 percent. But, because the continuous intake is positioned to take the suspension of a stratum in the stream which has a solids concentration higher than the average, the recovered product actually has a higher (or larger) concentration in about 3 percentage points than the average of the reactor suspension. Accordingly, the operation can approach an effective suspension concentration of 55 percent by weight or greater, that is 52 percent on average in the reactor and the removal of one component which is actually higher than 55 percent (ie 3 points in percentage). It should be emphasized that in a commercial operation, an increase as small as one percentage point is very significant. Therefore when going from a concentration of average percentage solids of 37-40 in the reactor to 41, this is important; consequently going up to an amount greater than 50 is truly outstanding. The present invention is applicable to any polymerization of olefins in a closed loop reactor that uses a diluent to produce a suspension of the product of the polymer and the diluent. Suitable olefin monomers are the 1-olefins having up to 8 carbon atoms per molecule and no branching closer to the double bond than the 4 position. The invention is particularly suitable for the homopolymerization of ethylene and the copolymerization of ethylene, and a Higher 1-olefin such as butene, 1-pentene, 1-hexene, 1-octene or l-decene. Ethylene and 0.01 to 10, preferably 0.01 to 5, more preferably 0.1 to 4 weight percent of the highest olefin are preferred, based on the total weight of the ethylene and the comonomer. Alternatively, sufficient comonomer can be used to give the above-described amounts of incorporation of the comonomer into the polymer. Suitable diluents (as opposed to solvents or monomers) are well known in the art and include hydrocarbons which are inert and liquid under the conditions of the reaction. Suitable hydrocarbons include isobutane, propane, n-pentane, i-pentane, neopentane and n-hexane, with isobutane being especially preferred. Suitable catalysts are well known in the art. Chromium oxide is particularly suitable on a support such as silica, as widely described, for example, in Hogan and Banks, US 2,285,721 (March 1958), the disclosure of which is incorporated herein by reference. Referring now to the drawings, there is shown in Figure 1, a closed loop reactor 10 having vertical segments 12, upper horizontal segments 14 and lower horizontal segments 16. These upper and lower horizontal segments define the upper and lower flow areas horizontal. The reactor is cooled by means of two tubular heat exchangers formed by the pipe 12 and the shell 18. Each segment is connected to the next segment by a soft or slightly pronounced elbow or bend 20 thus providing a substantially free continuous flow path of internal obstructions. The polymerization mixture is circulated by means of the impeller 22 (shown in Figure 8) driven by the engine 24. The monomer, the comonomer, if any, and the diluent of the composition are introduced through the lines 26. and 28 respectively, which may be introduced to the reactor directly at one or a plurality of sites or may be combined with the recirculation line 30 of the condensed diluent, as shown. The catalyst is introduced by the means 32 for introducing the catalyst, which provides a zone (location) for the introduction of the catalyst. The elongated hollow fitting for the continuous taking of a suspension of the intermediate product is largely designed by the reference character 34. The continuous take-off mechanism 34 is located at or adjacent a downstream end of one of the sections 16 of the closed circuit of the horizontal reactor, lower, and adjacent or on a connection elbow 20. The continuous intake fitting is shown at the downstream end of a lower horizontal segment of the closed loop reactor which is at the preferred location. The location can be in an area near the last point in the closed loop where the flow is turned upwards before the introduction point of the catalyst, so that the fresh catalyst is allowed as long as possible in the reactor before the First go to a take point. However, the continuous take-up fitting can be located in any segment or any elbow. Also, the segment of the reactor to which the continuous tap attachment is fixed may be of larger diameter to retard the flow and thereby further allow the stratification of the flow so that the falling product may have an even higher concentration of solids. The suspension of the continuously extracted intermediate product is passed through conduit 36 into a high pressure instantaneous distillation chamber 38. The conduit 36 includes a surrounding conduit 40 which is provided with a hot fluid that provides indirect heating to the material in suspension in the conduit 36 of the instantaneous distillation line. The evaporated diluent leaves the instantaneous distillation chamber 38 through the conduit 42 for further processing which includes the simple heat exchange condensation using the recycle condenser 50, and back to the system, without the need for compression, for medium of line 30 of the recycling diluent. The recycle buffer 50 may be any suitable heat exchange fluid known in the art under any conditions known in the art. However, a fluid at a temperature that can be provided economically is preferably used. A suitable temperature range for this fluid is 4.44 ° C (40 degrees F) to 54.44 ° C (130 degrees F). The polymer particles are extracted from the high pressure flash distillation chamber 38 via line 44 for further processing using techniques known in the art. Preferably, they are passed to a low pressure flash distillation chamber 46 and thereafter recovered as a polymer product via line 48. The separated diluent is passed through the compressor 47 to line 42. This design instant high pressure distillation is described extensively in Hanson and Sherk, US 4,424,341 (January 3, 1984), the description of which is incorporated herein for reference. Surprisingly, it has been found that the continuous intake not only allows a higher concentration of solids upstream in the reactor, but also allows the best operation of the high pressure instant distillation, thus allowing the majority of the extracted diluent to be fully distilled Quickly and recycled without compression. Actually, 70 to 90 percent of the diluent can be recovered in general in this way. This is because of several factors. First, because the flow is continuous rather than intermittent, the heaters of the instant distillation line work better. Also, the pressure drop after the proportional control valve that regulates the continuous flow rate out of the reactor has a lower pressure, which means that when the fluid is distilled instantaneously, the lower temperature is reduced thus giving further use efficient heaters of the instant distillation line. Referring now to Figure 2, there is shown the elbow 20 with the continuous take-up mechanism 34 in greater detail. The continuous take-up mechanism comprises a take-up cylinder 52, an extraction line 54 of the suspension, a total shut-off valve 55 for emergency, a proportional motor valve 58 for regulating the flow and a leveling line 60. The reactor is running full of "liquid". Because of the dissolved monomer, the liquid has a slight compressibility, thus allowing control of the pressure of the liquid-filled system with a valve. The diluent input in general is kept constant, the proportional motor valve 58 is used to control the speed of continuous extraction to maintain the total reactor pressure within the designated set points.

Referring now to Figure 3, which is taken along line 3-3 of the section of Figure 2, there is shown the smooth curve or elbow 20 associated with it the continuous take-up mechanism 34 with greater detail, the elbow 20 is thus an elbow that carries the accessory. As shown, the mechanism comprises a take-up cylinder 52 fixed, in this case, at a right angle with respect to the tangent of the outer surface of the elbow. The outlet cylinder 52 is the extraction line 54 of the suspension. Positioned inside the take-up cylinder 52 is a gate valve 62 which serves two purposes. In the first place, it provides a simple and reliable cleaning mechanism for the intake cylinder if it can become contaminated with the polymer. Secondly, it can serve as a simple and reliable total shut-off valve for the complete continuous tap assembly. Figure 4 shows a preferred fixing orientation for the take-up cylinder 52 where it is tangentially fixed to the curvature of the elbow 20 and at the point just before the flow of the suspension turns or returns upwards. This opening is helical with respect to the inner surface. An additional lengthening could be done to improve the intake of the solids.

Figure 5 shows four things. First, it shows an angled orientation of the take-up cylinder 52. The take-up cylinder is shown at an angle, alpha, in a plane that is (1) perpendicular to the center line of the horizontal segment 16 and (2) it is located at the downstream end of the horizontal segment 16. The angle with this plane is taken in the downstream direction from the plane. The vertex for the angle is the center point of the radius of the elbow as shown in Figure 5. The plane can be described as the plane of the cross section of the horizontal segment. Here, the angle shown is approximately 24 degrees. Second, it shows a plurality of continuous take-up accessories, 34, 34a. Third, it shows an accessory, 34 oriented on a vertical centerline plane of the lower segment 16, and the other, 34a, located at an angle with respect to such a plane as will be shown in greater detail in Figure 6. Finally, it shows the combination of the continuous tap fittings 34 and a conventional settling foot 64 for batch removal, if desired. As can be seen from the relative sizes, the continuous take cylinders are much smaller than the conventional settling legs. However, three 5.08 cm (2 inch) internal diameter continuous fittings can remove as much product suspension as 14 20.32 cm (8 inch) settling legs. This is significant because with commercial, large, common closed-loop reactors with a capacity of 56,775-68,130 liters (15,000-18,000 gallons), settling legs of 15.24 cm (6 inches) are required. It is not desirable to increase the size of the settling legs because of the difficulty in manufacturing reliable valves for larger diameters. As previously noted, doubling the diameter of the pipe increases the volume four times and there simply is not enough space so that four times as many settling legs are easily placed. Hence, the invention makes feasible the operation of more efficient, larger reactors. Reactors of 113,550 liters (30,000 gallons) or greater are made possible by this invention. In general, continuous take cylinders will have a nominal internal diameter within the range of 2.54 cm (1 inch) to less than 20.32 cm (8 inches). Preferably they will be about 5.08-7.62 cm (2-3 inches) in internal diameter. Figure 6 is taken along line 6-6 of the section of Figure 5 and shows the take-up cylinder 34a fixed at a location that is oriented at an angle, beta, with respect to a vertical plane that contains the central line of the reactor. This plane can be referred to as the vertical central plane of the reactor. This angle can be taken from any side of the plane or from both sides if it is not zero. The vertex of the angle is located in the center line of the reactor. The angle is contained in a plane perpendicular to the center line of the reactor as shown in Figure 6. It was pointed out that there are three orientation concepts here. First of all there is the orientation of the fixation device, ie tangential as in Figure 4 and perpendicular as in Figures 2 or 7 at any angle between these two limits of 0 to 90 degrees. Secondly, there is the orientation in relation to how far above the curve of the elbow is the fixation device as represented by the angle alpha (Figure 5). This can be any value from 0 to 60 degrees, but preferably it is from 0 to 40 degrees, more preferably from 0 to 20 degrees. In third place is the angle, beta, from the central plane of the longitudinal segment (Figure 6). This angle can be from 0 to 60 degrees, preferably from 0 to 45 degrees, more preferably from 0-20 degrees. Figure 7 shows a modality in which the continuous take-up cylinder 52 has an orientation of the fixation device from the perpendicular, an alpha orientation of 0 (inherent since it is at the end, but still above, the straight section), and a beta orientation of 0, ie it is straight on the plane of the vertical center line of the lower horizontal segment 16. Figure 8 shows in detail the driving means 22 for continuously moving the suspension along its flow path . As can be seen in this mode, the impeller is in a slightly enlarged section of pipe which serves as the propulsion zone for the circulating reactants. Preferably, the system is operated to generate a pressure difference of at least 1,266 kg / cm 2 (18 psig) preferably of at least 1,407 kg / cm 2 (20 psig), more preferably at least 1,548 kg / cm 2 (22 psig) between the upstream and downstream ends of the propulsion zone in a nominal 0.6096 (two foot) diameter reactor with a total flow path length of approximately 289.56 m (950 ft) using isobutane to predominantly manufacture ethylene polymers. As much as 3.51 kg / cm2 (50 psig) or more are possible. This can be done by controlling the rotation speed of the impeller, reducing the spacing between the impeller and the internal wall of the pump housing or using a more aggressive impeller design as is known in the art. This difference in the highest pressure can also be produced by the use of at least one additional pump. In general, the system is operated to generate a difference in pressure, expressed as a loss of pressure per unit length of the reactor, of at least 0.021 m (0.07 ft), generally 0.021 to 0.045 m (0.07 to 0.15). feet) of pressure drop by 0.3048 m (one foot) of reactor length for a reactor of nominal diameter of 30.48 m (24 inches). Preferably, this pressure drop per unit length is 0.027 m (0.09 ft) to 0.033 m (0.11 ft) for a reactor with a diameter of 60.96 cm (24 inches). For larger diameters, a higher suspension speed and a drop in the highest pressure per unit length of the reactor is necessary. The units for pressure are standing / standing which cancel. This means that presumably the density of the suspension is generally 0.5-0.6. Referring now to Figure 9, the upper segments are shown as 180 degree semicircles which are of the preferred configuration. The vertical segments are at least twice the length, generally about seven to eight times the length of the horizontal segments. For example, the vertical flow path can be 57.91 m (190 ft) - 68.58 m (225 ft) and the horizontal segments of 7.62 - 9.144 m (25 - 30 ft) in the length of the flow path. Any number of closed circuits can be used in addition to the four shown here and the eight shown in Figure 1, but in general four or six are used. With reference to the nominal diameter media of 0.6096 m (two feet), they are of an internal diameter of approximately 55.62 cm (21.9 inches). The flow length is generally greater than 152.4 m (500 ft), generally greater than 274.32 m (900 ft), with approximately 286.51 m (940 ft) up to 411.48 m (1,350 ft) which is completely satisfactory. Commercial pumps for utilities such as circulating reagents in a closed loop reactor are routinely tested by their manufacturers and the pressure necessary to prevent cavitation is determined easily and routinely.

EXAMPLES A vertical four-leg polymerization reactor using an impeller of the pump D51795 / 81-281 of Lawrence Pumps Inc. of 66.04 cm (26 inches) in a shell or shell M51879 / FAB, was used to polymerize ethylene and hexane -1. This pump was compared with a 60.96 cm (24 inch) pump which gave a less aggressive circulation (0.2011 m (0.66 ft)) of pressure drop against 0.2987 m (0.98 ft)). This was then compared to the same more aggressive circulation and a continuous take-up assembly of the type shown by the reference character 34 of Figure 5. The results are shown below.

DATA TABLE Although this invention has been described in detail for the purpose of illustration, it is not proposed to be limited by it, but is proposed to cover all changes within the spirit and scope thereof.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, property is claimed as contained in the following 15 20

Claims (35)

1. A process for polymerizing olefins, characterized in that it comprises: polymerizing, in a closed loop reaction zone, at least one olefin monomer in a liquid diluent to produce a fluid suspension comprising the liquid diluent and the solid olefin polymer particles.; maintaining a concentration of the solid olefin polymer particles in the suspension in the area of more than 40 weight percent based on the weight of the polymer particles and the weight of the liquid diluent; and for at least a portion of a production run, continuously extracting the suspension, which comprises removing the liquid diluent and extracting the solid polymer particles as an intermediate product of the process.

2. A process according to claim 1, characterized in that the olefin monomer comprises ethylene.

3. A process according to claim 1, characterized in that the olefin monomer comprises ethylene and 0.01-5 weight percent hexene based on the total weight of ethylene and hexane, and wherein the liquid diluent is cyclohexane.

4. A process according to any one of the preceding claims, characterized in that the concentration of the particles of the solid olefin polymer in said suspension, in said zone, is greater than 50 weight percent based on the weight of the polymer particles and the weight of the liquid diluent.

5. A process according to any of the preceding claims, characterized in that a difference in pressure of at least 1.26 kg / cm2 (18 psig) is maintained in a propulsion zone to circulate the suspension through the reaction zone.

6. A process according to any of the preceding claims, characterized in that a difference in pressure greater than 0.021 m (0.07 feet) by 0.3048 m (one foot) of the length of the reactor path is maintained in a propulsion zone.

7. A process according to claim 6, characterized in that the difference is within the range of 0.021 m (0.07 feet) up to 0.045 m (0.15 feet) /0.3048 m (one foot), per 0.3048 m (one foot) of the length of the flow path of the reactor.

8. A process according to any of the preceding claims, characterized in that the reaction zone is kept full of liquid.

9. A process according to any of the preceding claims, characterized in that the reaction zone has a volume greater than 75,700 liters (20,000 gallons).

10. A process according to claim 9, characterized in that the reaction zone has a volume greater than 113,550 liters (30,000 gallons).

11. A process according to any of the preceding claims, characterized in that the intermediate product of the process is continuously passed through a heating zone where the intermediate product is heated to produce an intermediate product and after this the hot intermediate is exposed to a drop in pressure in a high-pressure flash distillation zone, the hot intermediate is heated to a degree such that a larger portion of the extracted liquid diluent is evaporated and thus separated from the extracted solid polymer particles, the liquid diluent extracted thus, after this it is condensed so that it is recycled, without any compression, by heat exchange with a fluid having a temperature in the range of about 4.44 ° C (40 ° F) to about 54.44 ° C (130 °) F).

12. A process according to any of the preceding claims, characterized in that the suspension is continuously withdrawn from an area near the last point in the closed circuit reaction zone where the flow rotates or returns upwards before a catalyst introduction zone. .

13. A process according to any of the preceding claims, characterized in that the suspension is continuously withdrawn from at least one area adjacent the end of a lower horizontal flow zone.

14. A process according to claim 13, characterized in that the suspension is extracted at a point along the vertical center line plane of the lower horizontal flow area and prior to the flow of the return or back up.

15. A process according to claim 13, characterized in that at least one area is along the plane of the vertical center line of the lower horizontal flow zone and after the flow has turned or turned upwards.

16. A process according to claim 13, characterized in that an area is oriented at an angle away from the vertical central plane of the lower horizontal flow area in an amount within the range of 0 ° to 45 °.

17. A process according to claim 16, characterized in that at least one area is oriented away from the vertical central plane at an angle within the range from 0 ° to 20 °.

18. A process according to claim 16 or 17, characterized in that at least one area is before the flow of the turn or turn up.

19. A process according to claim 16 or 17, characterized in that at least one area is in a location after the flow has turned or has turned upward to at least 1 but less than 45 ° from a central line of the flow towards above.

20. A process according to any of the preceding claims 13-19, characterized in that at least one area is exactly one area.

21. A process according to any of the preceding claims 13-19, characterized in that at least one area is a plurality of areas.

22. A process according to any of the preceding claims, characterized in that it includes adjusting the conditions of the reactor during the start of the process using continuous extraction of the suspension to raise the solids content of the reactor by at least 10 percent.

23. A process according to any of claims 1-22, characterized in that the suspension is continuously extracted substantially from beginning to end of a production run.

24. A process according to any of claims 1-22, characterized in that during the run of production, a step of continuous extraction of the suspension is alternated with a step comprising: extracting the suspension, allowing the suspension to settle to at least a sedimentation zone and thereafter extract a batch of the suspension so sedimented from the sedimentation zone as an intermediate product of the process, and after that completely close the sedimentation zone.

25. A closed loop reactor apparatus for the polymerization of olefins, characterized in that it comprises: a plurality of vertical segments; a plurality of upper horizontal segments; a plurality of lower horizontal segments; wherein each of the vertical segments is connected at an upper end thereof by a smooth upper bend or bend to one of the upper horizontal segments, and is connected at a lower end thereof by a smooth lower bend or elbow to one of the lower horizontal segments, thus defining a continuous flow path adapted to convey a fluid suspension, the reactor is substantially free of internal obstructions; means for introducing the monomer reagent, the polymerization catalyst and the diluent into the reactor; means for continuously moving the suspension along the flow path; at least one elongated hollow fitting adjacent to a downstream end of one of the lower horizontal sections, the fitting is in open communication with the flow path to continuously extract the suspension from the product; and an elongated instant distillation line in fluid communication with the accessory, to transfer the suspension of the product from the accessory to the instant distillation means, the instant distillation line has a heater associated therewith to heat the suspension of the product.

26. An apparatus according to claim 25, characterized in that at least one accessory is fixed to one of the lower horizontal segments thus providing a lower horizontal segment carrying the accessory, the accessory is oriented along a vertical centerline plane of the horizontal lower segment that carries the accessory and adjacent to the elbow or soft bottom fold fixed to the downstream end of the lower horizontal segment that carries the accessory.

27. The apparatus according to claim 25, characterized in that the accessory is fixed at an angle of between 0 and 90 °.

28. An apparatus according to claim 25, characterized in that at least one accessory is fixed to the soft bend or elbow fixed to the downstream end of the lower horizontal segment carrying the accessory, thereby providing a soft bend or bend that carries the accessory.

29. An apparatus according to claim 28, characterized in that the accessory is fixed to the soft bend or bend that carries the accessory at a point of at least 1 but less than 45 ° from a central line of the adjacent vertical segment.

30. An apparatus according to claim 28, characterized in that the accessory is fixed at an angle of between 0 and 90 °.

31. An apparatus according to claim 29, characterized in that at least one accessory is fixed at a right angle with respect to the tangent of the elbow or fold that carries the accessory.

32. An apparatus according to claim 29, characterized in that at least one accessory is tangentially fixed to the elbow or fold that bears the accessory.

33. An apparatus according to claim 32, characterized in that at least one accessory is fixed at a spaced point away from the vertical central plane in an amount within the range of 20-45 °.

34. An apparatus according to any of claims 28-33, characterized in that at least one accessory is exactly an accessory.

35. An apparatus according to any of claims 28-33, characterized in that at least one accessory is a plurality of accessories.