WO2006060928A2

WO2006060928A2 - Dropper plant

Info

Publication number: WO2006060928A2
Application number: PCT/CH2005/000720
Authority: WO
Inventors: Klaus Nothelfer; Theodor JÜRGENS; Andreas Christel; Brent Allan Culbert
Original assignee: Bühler AG
Priority date: 2004-12-07
Filing date: 2005-12-02
Publication date: 2006-06-15
Also published as: DE102004059069A1; WO2006060928A3

Abstract

The invention relates to a plant for the production of polymer particles, comprising: at least one reactor (10, 20) for the production of a polymer melt, two or more dropping towers (1a-1g), two or more dropping nozzles (5e), provided for each of the dropping towers (1a-1g), at least one melt line (11a-11d, 21a-21f), connecting the at least one reactor (10-20) with the two or more dropping nozzles (5e), two or more supply lines (3a, 3g), provided for each dropping tower (1a-1g), characterised in that the two or more supply lines are run together.

Description

Vertropfungsanlage

A large number of polymers are today produced and processed on a large scale. Many polymers are obtained as polymer melts, which must be converted into a solid form for further use, processing, storage or transport. The production of granules has proven to be particularly suitable. Depending on the viscosity of the polymer melts, various granulation methods are used, whereby a dropping process is suitable, above all for low-viscosity polymer melts.

Methods and plants for the production of polymer particles by dripping are known in the art.

WO 03/054063 (Culbert, Christel.) Describes the dripping of a polymer melt through a drop section into a receiving region, in which the particles are fluidized and thus guided to an outlet opening, in order subsequently to be further treated. On a large-scale, however, it may be necessary to operate several dropping devices in parallel. However, the method described has the disadvantage that the diameter of the receiving region is coupled to the diameter of the drop zone, and that when multiple dropletizing devices are used, either a plurality of receiving regions or a very large common receiving region must be provided. Since the amount of gas required for turbulence is directly proportional to the diameter of the receiving area, correspondingly large quantities of gas must be supplied and led away again, which leads to an overall uneconomical operation.

Moreover, WO 03/054063 always starts with the use of a dropletizing device. It is not described how to build up the supply of the melt and the removal of the particles in order to achieve a uniform product quality when using several dropletizing devices. WO 01/81450 (Matthaei, Locker ...), WO 02/18113 (Geier, Jürgens) and WO 00/24809 (Geier, Jürgens) also describe processes for dripping a polymer melt, wherein the particles in the drop tower to achieve crystallization with be subjected to a gas countercurrent. However, the described methods have the disadvantage that, when using a plurality of dropletizing devices, either a plurality of drop sections or a very large common drop section must be made available. Since the required amount of gas is directly proportional to the diameter of the fall distance correspondingly large amounts of gas must be supplied and led away again, resulting in a total uneconomic operation.

These applications also only describe the use of a dropping device. It will not be described how to build up the supply of the melt and the removal of the particles in order to achieve a uniform product quality when using several dropletizing devices.

task

On the other hand, it is the object of the present invention to provide an apparatus and a method which makes it possible to juxtapose several dropletizing devices, thereby improving the economic efficiency and ensuring the uniformity of the product.

The object is achieved according to claim 1 by a plant for the production of polymer particles, which comprises:

> at least one reactor for polymer melt production,

> two or more drip towers,

> two or more drip nozzles, which are assigned to the respective drip towers,

at least one melt line connecting the at least one reactor to the two or more drip nozzles,

> two or more delivery lines, each associated with one of the drip towers, characterized in that the two or more conveying lines are brought together.

This results in the advantage that large quantities of polymer particles can be produced without having to construct excessively large dropletizing devices. Another advantage is that individual drip towers can be parked for maintenance without having to interrupt the continuous process of polymer melt production, or to have to provide large buffer capacities for material produced in the meantime.

According to an advantageous embodiment of the system according to the invention, the delivery lines are delivery pipes. Preferably, the delivery pipes have a diameter compared to the diameter of the drip towers in the ratio of less than 1: 2, in particular less than 1: 5. By using delivery pipes, the polycondensate particles can be brought together quickly and in a space-saving manner, whereby the promotion a higher level is possible.

According to an alternative embodiment of the system according to the invention, the delivery lines are conveyor troughs. Optionally, vibrating elements (vibrators) can be attached to the conveyor troughs. The advantage of using conveyor troughs is that the polymer particles can be transported distributed over a large area. Vibration can reduce the agglomeration of polymer particles. Also by means of conveyors a promotion to a higher level is possible.

An advantageous embodiment of the inventive system, provides that the delivery lines, in particular the conveyor troughs are divided into several stages, which allows treatment of the polymer particles already in the delivery line, with the smallest possible residence time spectrum.

According to an advantageous embodiment of the system according to the invention, two or more delivery lines are combined in a further delivery line, whereby out of the advantage that the particles can be promoted by means of only one line to another process step.

According to an alternative embodiment of the installation according to the invention, two or more delivery lines are conveyed in an apparatus, such as e.g. a crystallizer, a sizing, a storage tank or a treatment vessel (reactor) merged.

In both cases, it is possible to treat polymer particles from several dropping devices together in one apparatus, with the result that the corresponding treatment step no longer has to be assigned to each individual dropping tower.

According to a preferred embodiment of the plant according to the invention, the drip nozzles are assigned to the upper area of the drip towers, the feed lines are assigned to the lower area of the drip towers and there are one or more openings for supplying a cooling medium. This results in the advantage that a cooling medium does not have to be passed from below past the polycondensate particles, or from above at the drip nozzle.

A further preferred embodiment of the system according to the invention provides that the at least one melt line has markings which are connected to at least one or more dripping nozzles. Preferably, the melt line is connected at both ends with at least one reactor for melt production and connected via branches with two or more drip nozzles.

This results in the advantage that an amount of polymer melt can be circulated and via the branches only a required amount of melt can be supplied to the respective dropping nozzles. If the amount circulated in the circuit is chosen to be sufficiently large, the residence time to reach the first branch is only slightly smaller than the residence time until the last branch is reached, which is important in many cases to achieve a constant and uniform product quality. A likewise preferred embodiment of the system according to the invention provides that two or more melt lines connect the two or more drip nozzles to at least one of the melt production reactors. This results in the advantage that over each melt line a desired amount of polymer melt can be promoted without affecting the feed through the other melt lines.

Further preferred embodiments of the system according to the invention provide that melt pumps or melt filters are arranged between the drip nozzles and the at least one melt-producing reactor.

An embodiment of the system according to the invention provides that there are one or more openings for the removal of the cooling medium in the drip towers. These may preferably be provided with a device for utilizing or recovering the process energy stored in the cooling medium, e.g. a heat exchanger or a steam turbine to be connected. The advantage here is the possibility to improve the energy efficiency of the entire system.

An embodiment of the inventive system provides that the drip nozzles each comprise a nozzle system, comprising at least one nozzle plate, at least one element spaced from the nozzle plate for vibration transmission and at least one opening into the gap melt feed opening.

Preferably, in each case a nozzle system comprises a nozzle package, comprising at least a nozzle pot, a nozzle plate, at least one element for vibration transmission and, between the nozzle plate and the element for vibration transmission, at least one melt supply opening.

This results in the advantage of a compact design and a simple and rapid replacement of entire nozzle packages. Further preferred is an arrangement in which at least one nozzle package is integrated in a nozzle bar.

A further embodiment of the system according to the invention provides that the at least one element for vibration transmission is connected to at least one vibration-transmitting element, the connection preferably being separable.

It is furthermore preferred if the at least one vibration-transmitting element is mounted movably relative to the nozzle system. These measures also simplify the maintenance or replacement of a nozzle package without the need to replace the entire nozzle system.

The object is also achieved according to claim 38 by a process for the preparation of polymer particles, which comprises the following steps:

> Producing a polymer melt in at least one reactor,

Conveying the polymer melt through at least one melt line, starting from the at least one reactor, to two or more drip nozzles,

> Shaping polymer particles from the polymer melt by simultaneously dripping through two or more dripping nozzles,

Solidifying the polymer melt in two or more drip towers associated with the respective drip nozzles;

Conveying the polymer particles through two or more delivery lines, each associated with one of the drip towers,

characterized in that the polymer particles are combined from the two or more delivery lines.

The process is particularly advantageous when the polymer melt is a polycondensate melt since, in particular, low-viscosity polycondensates are suitable for dripping and, owing to the possibility of crystallization in the dropping tower, there are energetic advantages. The process is also advantageous if, for cooling the polymer melt, a liquid cooling medium is used, since large amounts of polymer melt can be cooled by the required heat of vaporization with a small amount of cooling medium. At the same time, a protective film of the cooling medium on the surface of the drip towers can prevent the adhesion of polymer melt.

description

Suitable polymers are polymers which are liquid or which can be liquefied by heating. In particular, these are thermoplastic polymers, such as e.g. Polyolefins, polystyrene or polycondensates, such as polyester, polycarbonate or polyamide. However, it is also possible to use the not yet cured form of crosslinking polymers, such as thermosets or elastomers, and also polymer / solvent mixtures.

Reactors for polymer melt production are well described in the art. In principle, polymerization reactors are contemplated in which polymers are prepared in the liquid phase, e.g. Stirred tanks, cage reactors or disk reactors, or apparatus in which previously prepared polymers are melted, e.g. Extruder or kneader. In the reactors for polymer melt production, various parameters are regulated which have an influence on the quality of the polymer melt. For example, Pressure and temperature in the reactors, as well as the amount and composition of individual components supplied can be regulated. For example, in reactors for polycondensate melt production, the degree of polymerization is influenced by the prevailing negative pressure.

Nozzle systems are referred to as drip nozzles, from which a liquid, in particular a polymer melt, exits substantially downwards through a multiplicity of openings, forming a multiplicity of individual liquid droplets. To improve the formation of droplets, the nozzle or the liquid contained therein can be excited with a vibration.

The nozzle system consists at least of the components nozzle body, nozzle plate and element for vibration transmission. The nozzle body encloses a space in which the polymer melt is introduced and through which the polymer melt is directed towards the nozzle plate. The nozzle body has at least one opening for the supply of polymer melt. In order to achieve a uniform flow through the nozzle body, it is also possible to provide a plurality of openings for supplying the polymer melt. The nozzle body may be of individual construction or integrated into a nozzle bar. Such nozzle bars are known, for example, in spinning technology, where they are referred to as spinning bars. Such a structure is described in the reference "Ullmann's Encyclopedia of Industrial Chemistry; Fibers, 3 General Production Technology; The nozzle body is usually inserted from above (top loading) or from below (bottom loading) in the nozzle bar, but it is also conceivable to use a lateral insert.

The nozzle body may be formed as a nozzle pot, are incorporated or integrated into the other components of the nozzle system, from which a nozzle package is formed. In particular, the nozzle plate and the feed opening for the polymer melt, but also melt filter and distributor plates can be incorporated or integrated into the nozzle pot. According to the invention, the element for vibration transmission can also be installed or integrated in the nozzle pot. In this case, preferably, the element for vibration above the nozzle plate and the opening for melt supply is located between these two elements. The individual elements may e.g. be inserted, pressed, clamped or screwed, or be firmly connected to the nozzle body. The installation of the elements in the nozzle pot can be done directly or indirectly by means of holding devices.

The nozzle body may be directly connected to one or more polymer melt supply conduits, or connected to at least one orifice in the nozzle beam through which the polymer melt is fed.

The nozzle body is preferably tempered, in particular heatable, wherein the temperature can be made directly in the nozzle body or indirectly from outside can take place. The indirect temperature control can be done via the nozzle bar.

The installation of the nozzle bodies in the nozzle bars takes place e.g. analogous to the type known from spinning technology.

The nozzle plate has a plurality of holes through which the polymer melt exits. Usually, the nozzle plate is substantially round, but may also be polygonal, in particular rectangular. In the case of round nozzle plates, the nozzle holes are preferably arranged on one or more ring paths. The individual holes are preferably round, but may also have other cross sections, e.g. oblong, oval, star-shaped. Typical hole diameters are 0.1 mm to 5 mm, in particular 0.3 to 1 mm. The hole length corresponds to the nozzle plate thickness, wherein the hole may initially have a larger diameter on the inlet side and narrows conically in a transition region to the outlet side, the actual capillary out. If a rigid nozzle plate is used, the hole length is typically between 5mm and 100mm, more preferably between 10mm and 50mm. When using flexible nozzle plates, the hole length is typically between 0.1 mm and 5 mm. On the exit side, the hole edge can be sharp or rounded. The capillary usually has an L: D ratio of 1: 1 to 1:10.

The nozzle plate may be individually connected to the nozzle body, or constitute a part of a nozzle package. In the case of an individual attachment, it is again conceivable to assemble from above (top loading), from below (bottom loading) or a lateral insertion. Construction and production of a nozzle plate are basically also known from spinning technology and can be largely transferred to a nozzle plate of a dropletizing plant. The nozzle plate may be coated on the exit side, for example, to prevent adhesion of polymer components, or at least to simplify the cleaning. While the nozzle plate is usually made of metal, for example, a ceramic material can be used for coating. The element for vibration transmission is eg a movable membrane. It is connected to the nozzle body so that a melt outlet between the nozzle body and the element for vibration transmission is prevented. This is done, for example, by a clamping ring in which the element is clamped for vibration transmission. Alternatively, the element for vibration transmission can also be connected directly to the nozzle body. For mounting also sealing rings can be used. Preferably, the element for vibration transmission should be mounted substantially parallel to the nozzle plate. Other orientations, such as a conical course, but are also conceivable.

The vibration transmission element is connected to a vibrating element. For this purpose, preferably a rigid connection should be used to ensure the greatest possible power transmission. An at least slightly flexible connection is used when damping between the vibration transmitting element and the vibrating element is to be achieved.

For improved maintenance of a nozzle system, it is advantageous if the connection between the vibration transmitting element and the vibrating element is separable, e.g. To replace a nozzle body with the element for vibration transmission or a whole nozzle package without having to replace the vibration-transmitting element.

As a separable compound, e.g. Screw connections, connectors, clamp connections and the like. in question.

Furthermore, it is advantageous if the vibration-transmitting element is movably mounted, so that when working on the nozzle body or nozzle package, e.g. can be cleared out of the way by moving, tilting or swiveling.

For generating a large number of small particles, a high oscillation frequency must be generated. Typical frequencies are 50 to 5000 hertz, in particular from 200 to 1000 hertz. The vibration excitation is carried out, for example, electromagnetically, piezoelectrically or by electrostriction.

A nozzle system may comprise a plurality of elements for vibration transmission and / or a plurality of vibration-transmitting elements.

One possibility is the use of piezoelectric crystals for vibration excitation, which allows an assignment of a vibrating element to a nozzle hole.

Alternatively, the connection between the element for vibration transmission and the vibration-transmitting element can also be effected by a pipe or a hose, whereby the vibration transmission can be carried out hydraulically.

A further alternative is an arrangement in which the element for vibration transmission is connected directly to the vibrating element. As a result, the vibrating element can also become part of a nozzle package. A separable connection between the vibrating element and the associated energy source is advantageous.

An embodiment of the present invention provides that the nozzle plate is formed as a movable membrane with through holes for the polymer melt. The movable nozzle plate is for this purpose either connected directly to a vibration-transmitting element, or connected to a vibration transmission element, wherein the vibration transmission element is then connected to a vibration-transmitting element

As drip towers sheathing means are called, which fall through the melt drops and which usually solidify the melt drops. The drip towers may for example consist of a self-supporting, vertical tube or a suspended, flexible hose. They can be provided with an insulation layer and / or a tempered jacket. According to the invention, two or more drip towers are arranged in parallel per reactor. Each drip tower is associated with at least one drip nozzle. However, it can also be assigned to a drip tower several drip nozzles.

The drip towers are depending on the required throughput and the prevailing process conditions 0.5m to 100m, especially 3m to 30m, high and have a diameter of 0.1 m to 10m, in particular 0.5m to 3m.

The drip towers may have one or more feed openings and Wegfuhröffnungen. For example, cooling or heating media can be added through the supply openings or gas streams with which the fall rate or the temperature of the drops can be regulated. Through the Wegführöffnungen be supplied media or emerging from the polymer droplets substances such as monomers, solvents or blowing agents, lead away from the drip towers. Feed lines and discharge lines are usually located below the drip nozzles. If an arrangement provided above the drip nozzles, they must be sufficiently protected against the possible cooling effect of the media flowing past, which can be achieved for example by insulation or baffles. The relative arrangement of the supply lines and * ^{■ •} the Wegfuhrleitungen is not fixed, but they must be arranged so that unnecessarily strong turbulences are avoided in the trickling tower. The lines can only open from one side or radially distributed in the drip tower. A supply line may be located above, below or opposite a discharge line, resulting in a DC, counter or cross flow. By tangential blowing a rotation can be generated.

The supply lines and / or removal lines of several drip towers can be summarized, the quantity distribution e.g. can be controlled by flaps or valves.

As cooling or heating media appropriately tempered gases, such as nitrogen, air, CO ₂ , water vapor or gas mixtures and liquids or gas / liquid mixtures can be used. In particular, evaporating liquids having a boiling point below the melt temperature of the polymer melt are suitable as serving. If an evaporating cooling liquid is used, with which the polymer particles are cooled to a temperature below their boiling point, then a proportion of cooling liquid must be expected, which emerges together with the polymer particles from the drip towers. It is also possible to allow cooling liquids to condense on the surface of the drip towers, whereby adhesion of polymer particles to the drip tower surface can be prevented. It may also be advantageous for starting up a dropletizing device to prevent a thermally damaged starting product from adhering to the walls of the drip towers, in particular at its conical outlet parts, by means of a liquid film.

When dropping a polyester melt, e.g. Water and / or ethylene glycol.

To improve the energy efficiency of the process, it may be advantageous if the energy stored in an exiting, reheated cooling medium is recovered by means of energy recovery, e.g. by means of a heat exchanger or a steam turbine, at least partially recovered. For this it may be necessary to further heat or densify the warmed cooling media.

Furthermore, it is advantageous in many cases when gas streams and heating or cooling media are at least partially recirculated, often a cleaning step, such as e.g. a filtration, a condensation, a combustion, a washing or an adsorption, must be interposed.

The dripping device is a drip tower together with at least one associated drip nozzle and the associated supply and Wegfuhrleitungen for the polymer melt, cooling media, process gases and polymer particles called.

Further components of a dropletizing device may be, for example, devices for monitoring the conditions in the dropletizing device or the quality of the polymer particles produced, such as measuring instruments, sight glasses, lighting sources. As a source of illumination, for example, is a stroboscope whose frequency is tuned to the frequency of the drops produced. Melting lines connect the reactor for polymer melt production with the drip nozzles, wherein two or more drip nozzles are connected to a reactor. The melt lines can optionally be tempered. The melt lines can have openings through which additives can be introduced or further melts can be supplied. To improve the homogeneity of the polymer melt, the melt lines may contain active or passive mixing elements, such as static mixers.

To ensure the transport of the polymer melt through the melt line, one or more conveyors, e.g. Gear pumps or screw presses, be arranged between the reactor and the drip nozzles. To separate off any solid impurities, one or more melt filters may be arranged between the reactor and the dripping nozzles.

In many cases, it is necessary to achieve a uniform quality in a plurality of Vertropfungseinrichtungen operated in parallel, to keep the process conditions in the respective melt lines constant, with particular residence time, Tem-. temperature and shear rate in the units of dripping should not differ significantly.

This can e.g. be achieved by a star-shaped arrangement of the melt lines from the reactor to the drip nozzles. Depending on the number of drip nozzles, the following arrangements can be used:

> with two or more drip nozzles: starting from the reactor, a melt line to each drip nozzle. This arrangement is preferably applied to two to five drip nozzles.

> at three or more drip nozzles: starting from the reactor, at least two melt lines, wherein at least one melt line branches to two drip nozzles. This arrangement is preferably applied to four, six, eight, etc. drip nozzles. > at four or more drip nozzles: starting from the reactor, at least three melt lines, wherein at least one melt line branches to three drip nozzles. This arrangement is preferably applied to six, nine, twelve, etc. drip nozzles.

Another possibility offers a star-shaped division, from at least one leading away from the reactor main line, whereby also the star arrangements described above are preferred.

Another possibility is the construction of at least one loop, are fed by the two or more drip nozzles via branches.

In order to achieve as uniform a residence time distribution as possible from the first branch line to the last branch line in a ring line, it is advantageous if the throughput through the ring line is at least twice, in particular at least three times, the sum of the throughputs through all the branch lines. Accordingly, the cross section of the loop should be greater, in particular twice as large as the sum of all cross sections of Abzweigungslek lines.

In order to regulate each drop nozzle or group of drip nozzles and shut down and maintain as needed, it is advantageous if in each melt line to each drip nozzle or drop nozzle group a separate control and shut-off is included. As a regulating and blocking device, e.g. a melt conveying device (gear pump) or a control valve can be used.

Depending on the sum of all melt streams to the drip nozzles, a control to Prozessparametem in the reactor for polymer melt production must be done. Above all, the amount of components supplied must be regulated. Other parameters which have an influence on the quality of the polymer melt can also be regulated on the basis of the sum of all melt flows to the dripping nozzles. For example, in a reactor for producing polycondensate controlling negative pressure to keep the degree of polymerization constant.

Since a polymer melt can change negatively at a standstill in a melt line, it is advantageous if there is a drain opening in front of each drip nozzle, which can be opened when starting after a standstill.

Delivery lines are lines through which the solid polymer particles are led away from the drip towers. Each drip tower is assigned at least one delivery line.

According to the invention, two or more delivery lines are brought together in each case.

According to one subclaim, two or more delivery lines are combined in another delivery line. According to a further subclaim, two or more delivery lines in an apparatus, such as e.g. a crystallizer, a sizing sieve, a storage tank or a treatment tank (reactor) * -. merged. The treatment vessel may also be used to separate excess cooling medium from the polymer particles, e.g. can be done by means of an impact dryer, a centrifugal dryer, a perforated plate or sieve or thermally.

The delivery lines may be e.g. act around delivery pipes or conveyor troughs.

Depending on the required throughput, the delivery pipes have a diameter of 25mm to 2m, in particular 0.1m to 0.5m. The diameter of the delivery pipes is at least smaller than 1/2, in particular smaller than 1/5 of the diameter of the associated drip towers. The diameter of the delivery pipes can be changed over the length of the delivery pipe, in particular reduced. If a plurality of delivery pipes are brought together, the collection pipe can in turn have a larger diameter. The polymer particles flow from the inlet opening to the outlet opening of the conveyor pipes, for example by an applied gradient, a flow of a pumped medium (conveying gas or liquid conveyed) or by a mechanical transport device, such as a screw conveyor, wherein a screw conveyor can be equipped with open or continuous auger wings. It can also be arranged several augers next to each other, with a tightly meshing or not tightly meshing arrangement is conceivable.

The conveyors are upwardly open or closed conduits, usually of rectangular cross-section, through which the product is e.g. is moved by an applied slope, by a mechanical transport device, such as a conveyor belt, or by vibration.

The conveyor troughs may have a smaller, equal or greater width than the diameter of the associated drip tower.

The use of conveyors and delivery pipes can be combined.

The delivery lines can be tempered, in particular heated.

The conveyor lines, in particular the conveyor channels, can be subdivided into several stages, e.g. can be achieved in succession by means of built-in transverse elements to the flow direction or by the arrangement of several conveyor troughs.

The delivery lines may have holes through which, for example, excess cooling liquids, small particles (undersize), but not the specified polymer particles can escape. In particular with conveyor channels, a gas can be passed through the openings, which serves, for example, for drying and / or fluidizing the polymer particles. The hole size is between 2/3 and 1/20 of the average particle size according to the polymer particle size, giving hole sizes of typically 0.05mm to 3mm. The holes can also be designed in such a way that individual particles with size according to specification, but not agglomerates or oversized particles (oversize particles), can pass through. The hole size is in accordance with the PoIy mer particle size between 1.1 and 3 of the average particle size, which results in hole sizes of typically 0.3 mm to 15 mm.

If the diameter or the width of the delivery lines is smaller than the diameter of the drip towers, the delivery lines are connected by means of conical transition pieces with the drip towers. The conical transition pieces may also have holes through which e.g. Excess cooling liquids or a treatment gas, but can not escape the polymer particles.

For closing individual delivery lines, blocking devices, such as e.g. Flaps, sliders or locks (rotary valves) may be arranged in the delivery lines.

For separating unwanted product, e.g. Starting product, it may be advantageous if in each delivery line a branch, e.g. a pipe switch or the like is located.

The polymer particles are the solidified polymer melt drops. The polymer particles usually have a teardrop-shaped, spherical or spherical shape. They usually have an average particle size of 0.2 mm to 5 mm, in particular 0.5 mm to 2 mm.

Exemplary embodiments of the apparatus according to the invention are shown in FIGS. 1 to 6.

Figure 1 shows a part of the apparatus. Shown is the part for combining the polymer particles, consisting of seven drip towers (1a-1g), seven conical junctions (visible 2a-2e) and seven conveyor pipes (3a-3g). The delivery pipes are brought together in a common downpipe 4. By way of example, a start-up flap (110) is shown in a conveyor (3e). Similarly, a flap can be located in each of the delivery lines (3a - 3g). By way of example, the dripping nozzle (5e) and supply lines for water as the cooling medium (6e) and removal lines for water vapor (8e) are shown in the drip tower (1e). Analogously, a water distribution to the other drip towers via a distributor (7) and take place a merging of the Wegfuhrleitungen via a manifold (9).

Figure 2 shows a part of the apparatus. Shown is the part for distributing the polymer melt from the reactor (10) through four melt lines (11a-d) to four drop nozzles (12a-d). It is a star-shaped arrangement.

Figure 2a shows a plan view and Figure 2b shows a side view of the plant part.

FIG. 2b shows by way of example in line (11c) a melt pump (13c), a melt filter (14c) and a starting valve (15c). Analogously, these apparatuses can also be located in the other melt lines.

FIG. 3a shows another possible star-shaped arrangement of the melt lines (21a-f) from the reactor (20) to the drip nozzles (not shown).

Figure 3b shows an arrangement with a main line (51) from the reactor (50) to four melt lines (52a-d) leading to the drip nozzles (not shown).

In the main line there is a melt pump (53) and in the melt lines to the drip nozzles are melt pumps (54a - d). Again, in each case in the main line and / or in the melt lines to the drip nozzles melt filter and starting valves (not shown) are located. The speed signals of the individual pumps are matched to one another in a control unit (55) and optionally also used to control process parameters in the reactor (50) and any precursors associated with the reactor.

There are various possibilities for arranging and controlling the melt pumps: > The distributor pumps (54a-d) determine the melt flows to the individual drop nozzles and the main pump (53) must deliver the corresponding amount of melt from the reactor (50).

> Preferably, the delivery rates of the distributor pumps are kept constant (master) and the main pump is adapted (slave), which is e.g. can be done via a pressure control before the distribution pump.

> In the arrangement described above, when a distributor pump (e.g., 54d) is omitted from a melt line (e.g., 52d), the main pump 53 determines the flow of melt through this line (52d).

If, in the arrangement described above, a plurality of distributor pumps (54a-d) are omitted from a plurality of melt lines (52a-d), the main pump (53) determines the melt flow through this line (52a-d), the melt streams to the individual drop nozzles via valves (not shown) are regulated.

FIG. 4 shows a part of the apparatus. Shown is the part for distributing the polymer melt from the reactor (30) through a main melt line (31) and through five branch lines (32a-e) to five drop nozzles (33a-e). The main line is returned via a return line (39) in the reactor (30). It is an arrangement with a loop.

In the main line (31) are a melt pump (34) and a melt filter (35).

By way of example, a melt pump (36e), a melt filter (37e) and a start-up valve (38e) are shown in the line (32e). Analogously, these apparatuses can also be located in the other melt lines.

Figure 5 shows a part of the apparatus. Shown is the part for energy recovery.

Water vapor from the manifold (9) is fed via a line (43) in a heat exchanger (42). Optionally located in front of the heat exchanger a ^" compressor (41). A line (44) leads away from the heat exchanger, optionally via a further line (47), a closed circuit can be generated. Any necessary equipment for purifying the recirculating coolant (not shown) may be interposed therebetween. An inlet line (45) and an outlet line (46) for another process medium (gas or liquid) are connected to the heat exchanger (42).

In this way, e.g. a process gas, which is used for the thermal aftertreatment of the polymer particles, are heated.

FIG. 6 shows a cross section through a nozzle bar (60) with a round recess and a melt feed opening (61). Inserted therein is a round nozzle package (62) consisting of a nozzle pot (63), an inserted nozzle plate (64) with a nozzle hole ring (65), optionally a sieve package (66) and a tensioning device (67), into which a movable membrane ( 68) is clamped. With the tensioning device, the filter pack and the nozzle plate are pressed into the nozzle pot, e.g. by means of a thread or a screw (not shown). In the nozzle pot (63), in correspondence with the melt supply port (61), there is an inlet port (69) for the polymer melt. Attached to the membrane (68) is a connecting rod (70) which is connected by a coupling (71) to a vibrating element (72). The vibrating element is supported by a rotatable support frame (73).

Claims

claims

1. plant for the production of polymer particles which comprises

at least one reactor (10, 20) for polymer melt production,

> two or more drip towers (1a-1g),

two or more drip nozzles associated with the respective drip towers (1a-1g),

at least one melt line (11a-11d; 21a-21f) connecting the at least one reactor (10; 20) to the two or more drip nozzles,

two or more delivery lines (3a-3g), each associated with one of the drip towers,

characterized in that the two or more delivery lines (3a-3g) are merged.

2. Plant according to claim 1, characterized in that it is at the delivery lines to delivery pipes.

3. Plant according to claim 2, characterized in that the conveying pipes have a diameter compared to the diameter of the drip towers in the ratio of less than 1: 2, in particular of less than 1: 5.

4. Plant according to claim 1, characterized in that it is at the delivery lines to conveyors.

5. Plant according to claim 4, characterized in that on the conveyor troughs elements for vibration (vibrators) are mounted.

6. Plant according to one of the preceding claims, characterized in that the conveying lines, in particular the conveyor troughs are divided into several stages.

7. Installation according to one of the preceding claims, characterized in that the delivery lines are connected to the drip towers by means of conical transition pieces.

8. Installation according to one of the preceding claims, characterized in that two or more conveying lines are combined in a further conveying line.

Installation according to any one of the preceding claims, characterized in that two or more conveying ducts in an apparatus, e.g. a crystallizer, a sizing sieve, a reservoir or a treatment vessel (reactor) are brought together.

10. Installation according to one of the preceding claims, characterized in that each of the drip nozzles are associated with the upper region of the drip towers, and that in each case the delivery lines are associated with the lower portion of the drip towers, and that there are one or more openings for supplying a cooling medium therebetween ,

11. Installation according to one of the preceding claims, characterized in that the at least one melt line has one or more Abzeigungen, which are connected to one or more drip nozzles.

12. Plant according to claim 11, characterized in that the melt line is connected at both ends with at least one of the reactors for melt production and has Abzeigungen which are connected to two or more of the drip nozzles.

13. Plant according to one of the preceding claims, characterized in that two or more melt lines connect the two or more drip nozzles with at least one of the reactors for melt production.

14. Installation according to one of the preceding claims, characterized in that it is at least three drip towers in the two or more drip towers, wherein the two or more drip nozzles is at least three drip nozzles and is at the two or more delivery lines to at least three delivery lines ,

15. Plant according to one of the preceding claims, characterized in that at least one melt pump is arranged between the drip nozzles and the at least one reactor for the production of melt.

16. Plant according to claim 15, characterized in that each drip nozzle is associated with a melt pump.

17. Plant according to one of the preceding claims, characterized in that at least one melt filter is arranged between the drip nozzles and the at least one reactor for the production of melt.

18. Plant according to claim 17, characterized in that each drip nozzle is associated with a melt filter.

19. Plant according to one of the preceding claims, characterized in that there are one or more openings for Wegfuhr the cooling medium in the drip towers.

20. Plant according to claim 19, characterized in that the openings for Wegfuhr the cooling medium with at least one device for utilization or recovery of the process energy stored in the cooling medium, such as a heat exchanger or a steam turbine, is connected.

21. Installation according to one of the preceding claims, characterized in that the drip nozzles each comprise a nozzle system, comprising at least one nozzle plate, at least one element spaced from the nozzle plate for vibration transmission and at least one opening into the gap melt feed opening.

22. Plant according to claim 21, characterized in that in each case a nozzle system comprises a nozzle package, comprising at least a nozzle pot, a nozzle plate, at least one element for vibration transmission and, between the nozzle plate and the element for vibration transmission, at least one melt supply opening.

23. Plant according to at least one of claims 20 to 21, characterized in that the at least one element for vibration transmission is connected to at least one vibration-emitting element.

24. Plant according to claim 22, characterized in that the at least one element for vibration transmission is connected by means of a separable connection with at least one vibration-emitting element.

25. Plant according to at least one of claims 22 to 23, characterized in that the at least one vibrating element is mounted relative to the nozzle system movable.

26. Plant according to claim 22, characterized in that the at least one vibration-emitting element is fixedly connected to the element for vibration transmission and is connected by means of a separable connection to an energy source for vibration generation.

27. Plant according to at least one of claims 20 to 25, characterized in that the element for vibration transmission comprises a movable membrane.

28. Plant according to at least one of claims 20 to 26, characterized in that at least one nozzle package is integrated into a nozzle bar.

29. Plant according to at least one of claims 20 to 27, characterized in that the nozzle plate is designed as a movable membrane.

30 nozzle pack consisting at least of a nozzle pot, a nozzle plate and at least one melt supply port, characterized in that spaced from the nozzle plate, at least one element for vibration transmission, and that is at least one melt supply opening between the nozzle plate and the element for vibration transmission.

31. nozzle system consisting of at least one nozzle pack according to claim 29, characterized in that the at least one nozzle pack is inserted into a nozzle bar and the element for vibration transmission of the at least one nozzle pack is connected to a vibrating element.

32. nozzle system according to at least one of claims 29 to 30, characterized in that at least three nozzle packages are inserted into a nozzle bar.

33. nozzle system according to at least one of claims 29 to 31, characterized in that the at least one element for vibration transmission is connected by means of a separable connection with a vibration-emitting element.

34. nozzle system according to at least one of claims 29 to 32, characterized in that the vibration-transmitting element is mounted relative to the nozzle system movable.

35. nozzle system according to at least one of claims 29 to 33, characterized in that the vibration-emitting element fixed to an element for Vibration transmission is connected and connected by means of a separable connection to a power source for vibration generation.

36. nozzle system according to at least one of claims 29 to 34, characterized in that the element for vibration transmission comprises a movable membrane.

37. nozzle system according to at least one of claims 29 to 35, characterized in that the nozzle plate is designed as a movable membrane.

38. A process for the preparation of polymer particles which comprises the following steps:

> Producing a polymer melt in at least one reactor,

Conveying the polymer melt through at least one melt line starting from the at least one reactor to two or more drip nozzles,

> Molding polymer particles from the polymer melt by simultaneously dripping through two or more dripping nozzles,

39. The method according to claim 37, characterized in that it is at the delivery lines to delivery pipes or conveyor troughs.

40. Method according to one of the preceding claims, characterized in that the polymer melt is a polycondensate melt.

41. The method according to any one of the preceding claims, characterized in that the combined polycondensate particles are subjected to a further treatment in the solid phase, such. a crystallization, a drying, a classification and / or a polycondensation.

42. The method according to any one of the preceding claims, characterized in that a part of the polymer melt from the at least one reactor is conveyed through a melt line and recycled back into the reactor, wherein a portion of the polymer melt is conveyed via branch lines to two or more drip nozzles.

43. Method according to one of the preceding claims, characterized in that the two or more drip towers are at least three drip towers, wherein the two or more drip nozzles are at least three drip nozzles and wherein the two or more conveying lines are at least three conveying lines ,

44. The method according to any one of the preceding claims, characterized in that the polymer particles are cooled in the drip tower by means of a cooling medium.

45. The method according to claim 43, characterized in that the cooling takes place at least partially by means of a liquid cooling medium, that evaporates the cooling medium, the cooling medium vapor is discharged through lines from the drip towers and the cooling medium vapor is condensed for energy production or energy recovery.

46. The method according to any one of the preceding claims, characterized in that a liquid film on the surface of at least individual areas of the drip towers is generated, wherein a liquid film is produced in particular on a conical outlet part of the drip towers.