Multistage defoliation apparatus with at least one static mixer

Abstract

The present invention relates to a defoliation apparatus for defoliating a composition containing volatile components, comprising an inlet for the composition to be defoliated and at least two containers arranged in series with respect to at least two containers, each of which comprises at least one distributor, an outlet line for the defoliated composition and an outlet for gas, wherein at least one distributor of the first most upstream of the at least two containers comprises an inlet at its upstream end and an outlet at its downstream end, wherein at least one static mixer is located directly upstream of the distributor inlet or downstream of the distributor inlet but upstream of the distributor outlet, the inlet for the composition to be defoliated is connected to the at least one static mixer, and the outlet line for the defoliated composition of the first most upstream of the at least two containers is connected to a recirculation line that leads to the at least one static mixer to which the inlet for the composition to be defoliated is connected.

Description

Technical Field

[0001] The present invention relates to a multi-stage devolatilization apparatus for devolatilizing a composition containing volatile components, such as for devolatilizing a solid or liquid polymer composition containing unreacted monomers and solvents, a polymer preparation plant comprising such a multi-stage devolatilization apparatus, and a devolatilization method using such a multi-stage devolatilization apparatus.

Background Art

[0002] Devolatilization, i.e., degassing, respectively refers to removing gas, and other volatile substances such as solvents or moisture from solids and liquids under control. Devolatilization is usually used to remove volatile components, which are mostly components having a relatively low molecular weight such as residual monomers, solvents, reaction by-products and water from polymers. This devolatilization is necessary to achieve the required purity of each polymer before use by removing harmful and / or toxic components, components that adversely affect further processing of the polymer such as its moldability, components that deteriorate the properties of the polymer, components that cause an unpleasant odor of the polymer, and / or components that are otherwise undesirable. Further, by removing monomers and solvents from the polymer composition, it becomes possible to recover and potentially recycle the monomers and solvents during the process so as to increase the yield of the process and reduce the amount of waste.

[0003] To achieve devolatilization, the components to be evaporated must each have a higher partial pressure or thermodynamic activity than the polymer. Furthermore, the components to be evaporated must be able to diffuse through the polymer composition to the phase boundary. Specifically, in the case of viscous polymers or polymer melts, where the polymer and polymer melt typically have similar viscosity, a slow diffusion rate can be a rate limiting factor. Therefore, to accelerate devolatilization, the composition to be devolatilized is usually devolatilized at high temperatures and / or at pressures below atmospheric pressure. This is because both measurements increase the thermodynamic activity of the volatile components, and further, the viscosity of the polymer decreases as the temperature rises, thereby improving the diffusion of volatile components within the polymer. Typically, polymer devolatilization is carried out by preheating the composition to be devolatilized to very high temperatures under controlled pressure in a preheater, and then supplying the composition to a multi-stage devolatilization unit so that the volatile components evaporate and are separated from the polymer melt under the reduced pressure. Often, the composition to be deflated contains 60% or more volatile components, based on the total composition to be deflated, i.e., the polymer melt and volatile components combined. Typically, such multi-stage defoliation apparatus comprises three consecutive defoliation vessels that successively reduce the volatile component content in the polymer melt to low ppm levels. It is important that the volatile components vaporize into the gas phase during defoliation, developing and forming bubbles, which can diffuse from the polymer melt to the melt surface. A carefully designed defoliation method should be able to ensure that the separation steps described above reach equilibrium conditions.

[0004] Several types of devolatilization devices are known, including static and dynamic devolatilization devices. Dynamic devolatilization devices have moving parts such as blades to maintain a high interfacial concentration gradient and a high diffusion rate of volatile components within the polymer, while static devolatilization devices do not have moving parts but have internal structures such as one or more perforated trays, one or more structured packings, and / or one or more random packings to produce a high specific surface area of ​​the composition to be devolatilized and to distribute the composition to be devolatilized across the entire cross-section of the devolatilization device. However, dynamic devolatilization devices are associated with serious drawbacks due to their moving parts, such as high cost, high energy consumption during operation, the need for periodic maintenance, and a relatively high leakage rate.

[0005] Therefore, compared to dynamic devolatilization apparatuses, static devolatilization apparatuses have advantages such as lower energy consumption, lower installation costs, less maintenance required, and a relatively low leakage rate, due to the absence of moving parts. Common types of static devolatilization apparatuses include flash devolatilization apparatuses and falling strand devolatilization apparatuses. Flash devolatilization apparatuses typically comprise a preheater, such as a heat exchanger, and a flash chamber. During operation, the polymer composition to be devolatilized is first pumped to the heat exchanger, where it is heated and optionally pressurized to reduce its viscosity. The polymer composition is then pumped from the heat exchanger to the top of the flash chamber, where the pressure is released and the volatile components evaporate. A drop strand defoliation device operates similarly to a flash defoliation device, but includes one or more perforated trays to generate a high specific surface area of ​​the composition to be defoliated, to distribute the composition to be defoliated across the entire cross-section of the defoliation device, to form drop strands of the composition to be defoliated, to promote the development of volatile component bubbles, and to accelerate the diffusion process.

[0006] To provide flexibility with respect to the compositions to be defolable, such as polymers, the defolable apparatus should preferably be suitable for use in defolating a wide range of compositions, specifically compositions with relatively high viscosity and compositions with relatively low viscosity. Such flexibility is required in industrial polymerization plants because various product grades, including polymers with various molecular weights and / or polymers with various polymer structures such as linear, branched, and crosslinked structures, and consequently polymers with various viscosities, are produced in various subsequent batches in various subsequent production charges. Therefore, the defolable apparatus included in this polymerization plant should be able to process any of the produced batches independently of the viscosity of the polymer melt and should be able to provide an optimal residence time for defolating the polymer melt to the desired degree. However, to prevent the internal structure of the defolable apparatus from becoming blocked during the defolable of high-viscosity compositions, for example, by the blockage of openings in the internal structure by the high-viscosity composition to be defolable, defolable apparatuses are usually designed only for high-viscosity compositions. As a result, conventional devolatilization equipment is not at all optimized for devolatilizing low-viscosity compositions and performs insufficient devolatilization of low-viscosity compositions. Alternatively, devolatilization equipment may be designed to devolatilize only low-viscosity compositions. However, in this case, the devolatilization equipment cannot be used to devolatilize high-viscosity compositions.

[0007] Another drawback of a typical devolatilization apparatus equipped with a preheater is that it is not typically suitable for use with compositions to be devolatilized that contain one or more volatile compounds having low critical temperatures and low boiling points at operating pressure, such as 1-butene. In such cases, to avoid the formation of heterogeneous flow during devolatilization, the composition to be devolatilized must be supplied directly to the first devolatilization vessel without preheating. Furthermore, the first devolatilization vessel requires a recirculation line to recirculate the loop flow of the polymer molten material to reach the required operating temperature of the devolatilization vessel. Thus, the first devolatilization vessel must have two separate inlet nozzles, where the temperatures and compositions of the two flows being processed are significantly different. This results in the vaporization of separate volatile substances under different conditions, and a heterogeneous mixture is collected at the bottom of the devolatilization vessel. As a result, devolatilization may not reach equilibrium conditions due to the heterogeneity of mass and temperature. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International Publication No. 2010 / 066457 [Patent Document 2] European Patent Application Publication No. 1206962 [Patent Document 3] European Patent No. 2158027 [Patent Document 4] European Patent No. 0655275 [Patent Document 5] U.S. Patent No. 3743250 [Patent Document 6] European Patent No. 2548634 [Patent Document 7] European Patent No. 0815929 [Patent Document 8] European Patent No. 1510247 [Patent Document 9] U.S. Patent No. 4093188 [Patent Document 10] U.S. Patent No. 4,296,779 [Overview of the project] [Problems that the invention aims to solve]

[0009] In this regard, the fundamental objective of the present invention is to provide a devolatilization apparatus for devolatilizing compositions containing volatile components, such as for devolatilizing solid or liquid polymer compositions containing unreacted monomers, solvents, and / or by-products. The devolatilization apparatus enables efficient and low operating cost devolatilization in a compact design not only of high-viscosity compositions having a kinematic viscosity of at least 1,000 Pa·s, but also of low-viscosity compositions having a kinematic viscosity of less than 1,000 Pa·s, particularly less than 100 Pa·s. Therefore, the devolatilization apparatus is scalable and may be used to devolatilize polymer melts, such as polycaprolactone polymer melts, for various grades of polymers. The devolatilization apparatus enables efficient and low operating cost devolatilization of compositions containing one or more volatile compounds having a low critical temperature and low boiling point at operating pressure, such as 1-butene. [Means for solving the problem]

[0010] According to the present invention, a defoliation apparatus for defoliating a composition containing volatile components, such as for defoliating a solid or liquid polymer composition containing unreacted monomers, solvents, and / or by-products, the defoliation apparatus comprises an inlet for the composition to be defoliated and at least two containers arranged in series with respect to each of the at least two containers, each of which comprises at least one distributor, an outlet line for the defoliated composition, and an outlet for gas, and at least one distributor of the first most upstream of the at least two containers comprises an inlet at its upstream end and an outlet at its downstream end, and at least one static mixer This objective is satisfied by providing a defoliation apparatus in which a mixer is located directly upstream of the inlet of the distributor, or downstream of the inlet of the distributor but upstream of the outlet of the distributor, the inlet for the composition to be defoliated is connected to at least one static mixer, and the outlet line for the defoliated composition of the first upstream container of at least two containers is connected to a recirculation line that leads to at least one static mixer to which the inlet for the composition to be defoliated is connected.

[0011] By positioning the static mixer directly upstream of the inlet of at least one distributor in the first most upstream of at least two containers, or downstream of the inlet of that at least one distributor but upstream of the outlet of that at least one distributor, and by connecting the inlet for the composition to be deflated in the defloration apparatus to the static mixer, the first container does not require two different inlets or nozzles, namely one for the composition to be deflorated and the other for the recirculation portion of the liquid composition, and therefore, two different fluid flows are not processed during the operation of the first container. Conversely, due to the static mixer, the first container of the defloration apparatus according to the present invention has only one inlet for both the composition to be deflorated and the recirculation portion of the liquid composition drawn from the outlet line for the deflorated composition. Furthermore, the mixing achieved by the static mixer increases the formation of bubble nuclei of volatile components and results in homogenization of the two liquid flows, namely the composition to be deflorated and the recirculation portion of the liquid composition drawn from the outlet line for the deflorated composition, before the mixture is introduced into the first container via the distributor. This increases the separation of volatile components from the liquid phase. In addition, this allows for adjustment of suitable operating pressure and operating temperature, thus enabling the processing of compositions containing volatile components having low critical temperatures. Overall, the devolatilization apparatus according to the present invention enables the efficient and low-cost devolatilization of compositions containing volatile components, such as solid or liquid polymer compositions containing unreacted monomers, solvents, and / or by-products, in a compactly designed apparatus. The devolatilization apparatus can be used not only to devolatilize high-viscosity compositions having a kinematic viscosity of at least 1,000 Pa·s, but also to devolatilize low-viscosity compositions having a kinematic viscosity of less than 1,000 Pa·s, particularly less than 100 Pa·s, and specifically to devolatilize compositions containing one or more volatile compounds having low critical temperatures, such as 1-butene.

[0012] According to the present invention, a static mixer is defined as a stationary device comprising at least two deflection means, not openings, orifices, for mixing a single-phase or two-phase fluid flow, preferably continuously. Preferably, the static mixer comprises a housing having one or more inlets, one or more outlets for the mixed fluid, and an internal flow path in which at least two deflection means are arranged. Furthermore, it is preferable that the at least two deflection means are selected from the group consisting of plates, bars, crossbars, baffles, helically formed deflection means, grids, and any combination of two or more of the aforementioned deflection means. In addition, it is preferable that the static mixer comprises at least three, more preferably at least five, and even more preferably at least ten deflection means, where each bar, plate, crossbar, helically formed deflection means, and grid counts as one deflection means. Specifically, the static mixer is designed to achieve a mixing effect for layered single-phase fluid flows and even more so for two-phase fluid flows. A static mixer extracts energy from the fluid itself to mix the fluid flow, requiring no additional power source.

[0013] According to the present invention, at least one distributor of the first most upstream of the two containers comprises an inlet at its upstream end and an outlet at its downstream end, and at least one static mixer is located directly upstream of the distributor's inlet, or downstream of the distributor's inlet but upstream of the distributor's outlet, with an inlet for the composition to be defolatized connected to the at least one static mixer. Therefore, the at least one static mixer may be located within the distributor or connected to the distributor. Preferably, the at least one static mixer is directly connected to the inlet at the upstream end of the distributor, i.e., located directly upstream of the inlet at the upstream end of the distributor, or the at least one static mixer is connected via a line to the inlet at the upstream end of the distributor. When the at least one static mixer is connected via a line to the inlet at the upstream end of the distributor, the distance between the outlet of the at least one static mixer and the inlet of the distributor is preferably 10 cm or less, more preferably 5 cm or less, and even more preferably 0.5 cm or less. When at least one static mixer is directly connected to the upstream end of the distributor, the outlet of the static mixer is in contact with the inlet of the distributor; in other words, in this embodiment, at least one distributor of the first most upstream of the at least two containers has an inlet at its upstream end and an outlet at its downstream end, and at least one static mixer is positioned such that its outlet is directly upstream of the inlet of the distributor.

[0014] Alternatively, at least one distributor of the first most upstream of the two containers comprises at least one static mixer, the static mixer positioned downstream of the distributor inlet but upstream of the distributor outlet. For example, the static mixer may be positioned within the distributor such that the distance between the distributor inlet and the uppermost end of the static mixer is less than 20%, preferably less than 10%, more preferably less than 5%, and most preferably less than 1% of the distributor length. In this embodiment, it is preferable that the static mixer is positioned such that the distance between the distributor inlet and the uppermost end (i.e., the inlet) of the static mixer is 10 cm or less, preferably 5 cm or less, and more preferably 1 cm or less. More preferably, the static mixer is located directly downstream of the inlet of the distributor, i.e., at least one distributor of the first most upstream of the two containers has an inlet at its upstream end and an outlet at its downstream end, and at least one static mixer is located directly downstream of the inlet of the distributor, i.e., the inlet of the static mixer is in contact with the inlet of the distributor.

[0015] According to the present invention, the outlet line for the defolable composition of the first and most upstream of the at least two vessels of the defolable apparatus is connected to a recirculation line that leads to at least one static mixer to which the inlet for the composition to be defolable is connected. Thereafter, the composition to be defolable and the recirculated portion of the liquid composition drawn from the outlet line for the defolable composition are mixed together in the same static mixer, which increases the formation of bubble nuclei of volatile components and causes homogenization of the two liquid flows, namely the composition to be defolable and the recirculated portion of the liquid composition drawn from the outlet line for the defolable composition, before the mixture is introduced into the first vessel via a distributor. This increases the separation of volatile components from the liquid phase. In addition, this allows for the adjustment of suitable operating pressure and operating temperature, thus enabling the processing of compositions containing volatile components with low critical temperatures.

[0016] Good results are particularly achieved when the preheater is arranged in the recirculation line upstream of at least one static mixer. This makes it possible to easily control the operating temperature in the vessel by adjusting the appropriate preheater temperature and / or by adjusting the appropriate flow rate of the recycled liquid.

[0017] It is also possible to arrange a backpressure valve in the recirculation line upstream of at least one static mixer.

[0018] More preferably, the recirculation line comprises a preheater and a backpressure valve, and the backpressure valve is arranged upstream of at least one static mixer while being downstream of the preheater.

[0019] According to the present invention, at least two vessels are arranged in series with each other. Thus, the outlet line of each upstream vessel is connected to the inlet of the next downstream vessel. As a result, the outlet line for the devolatilized composition of the first most upstream vessel among at least two vessels is preferably connected to a connecting line that leads to the inlet of the second next downstream vessel among at least two vessels. When the first most upstream vessel among at least two vessels also comprises the aforementioned preferred recirculation line, the outlet line for the devolatilized composition of the first most upstream vessel among at least two vessels may be divided into a recirculation line and a connecting line. Alternatively, the first most upstream vessel among at least two vessels may comprise two outlet lines for the devolatilized composition, one connected to the recirculation line and the other connected to the connecting line.

[0020] According to a further particularly preferred embodiment of the present invention, the outlet line for the devolatilized composition of the second next downstream vessel among at least two vessels is connected to the recirculation line, and the recirculation line becomes a combined connecting and recirculation line that is connected to the connecting line and combined to also be represented as the inlet line of the second vessel.

[0021] The connecting line that leads from the outlet for the devolatilized composition of the first container to the inlet of the second container more preferably comprises a preheater. Thereby, by adjusting an appropriate preheater temperature and / or by adjusting an appropriate flow rate of the recycled liquid, it becomes possible to easily control the operating temperature within the second container. Preferably, the preheater is positioned downstream in the connecting line of the position where an optional but preferred recirculation line connects to the connecting line.

[0022] In a further development of the idea of the present invention, it is proposed that the connecting line that leads from the outlet for the devolatilized composition of the first container to the inlet of the second container comprises a static mixer and / or a backpressure valve. Good results are particularly obtained when the connecting line comprises a static mixer and a preheater, and the static mixer is arranged downstream of the position where an optional but preferred recirculation line connects to the connecting line while being upstream of the preheater. In addition, the connecting line may comprise a backpressure valve and / or a (further) static mixer arranged within the distributor or connected to the inlet of the distributor of the second container. Most preferably, the connecting line comprises, in order in the downstream direction, a static mixer, a preheater, and a (further) static mixer arranged within the distributor or connected to the inlet of the distributor of the second container, downstream of the position where an optional but preferred recirculation line connects to the connecting line. In the last embodiment, preferably, the backpressure valve is not arranged in the connecting line.

[0023] As in the case of the first container, the (further) static mixer in the connection line leading to the second container is preferably connected to the distributor of the second container. More preferably, the (further) static mixer is directly connected to the upstream end of the distributor, i.e., located directly at the upstream end of the distributor, or connected to the upstream end of the distributor via a line. The upstream end of the distributor of the second container is preferably the inlet of the distributor. When the (further) static mixers are each connected to the upstream end i.e., the inlet of the distributor via a line, the distance between the outlet of the (further) static mixer and the inlet of the distributor of the second container is preferably 10 cm or less, more preferably 5 cm or less, and even more preferably 0.5 cm or less. When the (further) static mixer is directly connected to the upstream end of the distributor of the second container, the outlet of the static mixer is in contact with the inlet of the distributor. In this embodiment, even if the connection line could be equipped with a back pressure valve, it is preferable that the connection line is not equipped with a pressure valve.

[0024] In further development of the concept of the present invention, it is suggested that the defolatorial apparatus according to the present invention comprises at least one further container, such as one to five further containers arranged in series with respect to one another downstream of the second container, each of which comprises at least one distributor, an outlet line for the defolatorialized composition, and an outlet for the gas. More preferably, the defolatorial apparatus comprises just one further third furthest downstream container comprising at least one distributor, an outlet line for the defolatorialized composition, and an outlet for the gas, wherein the outlet line for the defolatorialized composition of the second container is connected to a connecting line that leads to the inlet of the third container.

[0025] Preferably, the connection line leading to the inlet of the third vessel comprises i) a preheater and / or ii) a back pressure valve and / or a static mixer. Particularly good results are obtained when the connection line comprises a preheater and a static mixer, and the static mixer is located downstream of the preheater but upstream of the inlet of the distributor of the third vessel. A recirculation line is undesirable for the third vessel. Furthermore, it is preferable that the back pressure valve is not located in the connection line leading to the inlet of the third vessel.

[0026] As in the case of the first and second containers, the static mixer in the connecting line leading to the third container is preferably connected to the distributor of the second container. More preferably, the static mixer is directly connected to the upstream end of the distributor, i.e., located directly at the upstream end of the distributor, or connected to the upstream end of the distributor via a line. The upstream end of the distributor of the third container is preferably the inlet of the distributor. When the static mixers are connected to the upstream end, i.e., the inlet, of the distributor via a line, the distance between the outlet of the static mixer and the inlet of the distributor of the second container is preferably 10 cm or less, more preferably 5 cm or less, and even more preferably 1 cm or less. When the static mixer is directly connected to the upstream end of the distributor of the second container, the outlet of the static mixer is in contact with the inlet of the distributor. In this embodiment, even if the connecting line could be equipped with a back pressure valve, it is preferable that the connecting line is not equipped with a pressure valve.

[0027] Preferred examples of static mixers include X-type static mixers, vortex / spiral-type static mixers, quattro-type static mixers, baffle-plate-type static mixers, turbulator-strip-type static mixers, and any combination of two or more of the above-mentioned mixer types. An X-type static mixer comprises deflection means in the form of bars, crossbars, plates, etc., having an X-shaped configuration in plan view, side view, and / or cross view. Such X-type static mixers are described, for example, in International Publication No. 2010 / 066457, European Patent Application Publication No. 1206962, European Patent No. 2158027, and European Patent No. 0655275, and are commercially available from Sulzer Chemtech Ltd, Winterthur, Switzerland under the trade names SMX, SMXL, and SMX plus, and from Fluitec, Neftenbach, Switzerland under the trade name CSE-X. A vortex / spiral static mixer has a spirally formed deflection means, as described, for example, in U.S. Patent No. 3,743,250, while a quattro static mixer has a deflection means that forms a chamber-like mixing area, as described, for example, in European Patent No. 2,548,634 and European Patent No. 0,815,929. A baffle plate static mixer usually has a longitudinal deflection means, as described, for example, in European Patent No. 1,510,247 and U.S. Patent No. 4,093,188, while a turbulator strip static mixer has a plurality of elongated strips inside a tube, as described, for example, in U.S. Patent No. 4,296,779, each elongated strip being formed by a series of alternating deflection panels that are continuously joined together, for example, by substantially triangular bridging portions, with the strips held together and substantially fixed to the axis of the tube by every other portion of the bridging portions, and the other bridging portions being located adjacent to the inner wall of the tube. Other suitable static mixers are available from Sulzer Chemtech AG under the trade names CompaX, SMI, KVM, SMV, and GVM, and from Stamixco AG, Wollerau, and Switzerland under the trade name GVM.From the above standpoint, it is preferable that at least one, more preferably all, of the at least one static mixers in the at least two distributors be selected from the group consisting of X-type static mixers, vortex / spiral-type static mixers, quattro-type static mixers, baffle plate-type static mixers, turbulator / strip-type static mixers, and any combination of two or more of the above mixer types.

[0028] Each container in this daphne apparatus is equipped with at least one distributor. Particularly good results are obtained when each container is equipped with (exactly) one distributor.

[0029] Further development of the concept of the present invention suggests that each of the at least one distributors of each of the at least two containers comprises a pipe or an upstream portion that is a pipe. The pipe or portion that is embodied as a pipe may have any kind of cross-sectional shape, such as circular, square, rectangular, elliptical, oblong, or polygonal cross-sectional shapes. Preferably, the pipe or portion that is embodied as a pipe has a circular cross-section. Most preferably, each of the at least two distributors is a pipe having an inclined downstream end.

[0030] Preferably, each of the at least two distributors is positioned at least substantially horizontally in the container and extends from one end of the container over 20-98%, preferably 30-95%, more preferably 40-90%, of the container's width. Being at least substantially horizontal means that the angle between the longitudinal direction of the distributor and the horizontal plane is less than 20°, preferably less than 10°, more preferably less than 5°, even more preferably less than 1°, and most preferably 0°.

[0031] To produce a high specific surface area of ​​the composition to be devolated and to distribute the composition to be devolated across the entire cross-section of the devolating apparatus, it is even more preferable that at least one internal structure is located below each of the distributors in each of the at least two containers. Particularly good results are obtained when the at least one internal structure is selected from the group consisting of perforated trays, structural filling elements, random filling elements, and any combination of two or more of the above-mentioned internal structures.

[0032] In a particularly preferred embodiment of the present invention, in each of at least two containers, 1 to 20, preferably 1 to 10, more preferably 1 to 5, most preferably 1, 2, or 3 perforated trays are arranged below each of the dispensers. Each perforated tray may have multiple openings, and each opening in a given tray has at least substantially the same cross-sectional area. In this context, at least substantially the same cross-sectional area means that each opening has 70 to 130%, preferably 80 to 120%, more preferably 90 to 110%, even more preferably 95 to 105%, and most preferably the same cross-sectional area of ​​the average cross-sectional area of ​​the openings in the respective trays. Furthermore, it is preferable that each perforated tray has multiple openings, and the average cross-sectional area of ​​the openings in a tray arranged in one container may be the same as or different from the average cross-sectional area of ​​the openings in a perforated tray arranged in another container.

[0033] According to an alternative, particularly preferred embodiment of the present invention, in each of at least two containers, 1 to 20 beds, preferably 1 to 10 beds, more preferably 1 to 5 beds, most preferably 1, 2, or 3 beds of structural packing elements are arranged below each of the distributors. Preferably, each structural packing element is a so-called cross-channel corrugated sheet packing, which is assembled from a plurality of corrugated sheets, which are arranged in contact with each other so as to be parallel and touching. Preferably, the corrugated metal sheets are fastened to each other by several rods that penetrate the corrugated sheets and are perpendicular to the longitudinal region of the corrugated sheets, and the rods are fastened to the first and last corrugated sheets by washers and nuts or by bending the rods. Each corrugated sheet preferably has a plurality of alternately oriented peaks and valleys, and adjacent corrugated sheets are oriented such that the corrugations of adjacent corrugated sheets cross the corrugations of corrugated sheets that extend diagonally with respect to the vertical or longitudinal direction, thereby forming a continuous ramp that crosses each other. These passages positively influence the flow of the gas and liquid phases within the packing material, promoting mass transfer between the phases. In other words, the gas and liquid phases are brought into contact in the passages of the structural packing elements, thus facilitating mass transfer and heat transfer between the phases.

[0034] According to a further alternative and particularly preferred embodiment of the present invention, in each of at least two containers, 1 to 20 beds, preferably 1 to 10 beds, more preferably 1 to 5 beds, and most preferably 1, 2, or 3 beds of random filling elements are arranged below each of the dispensers.

[0035] In a further embodiment, the present invention relates to a polymer preparation plant comprising at least one polymerization reactor, the outlet of at least one polymerization reactor being connected to at least one of the above-mentioned defoliation devices.

[0036] In a further embodiment, the present invention relates to a method for defolazing a composition containing volatile components, such as for defolazing a solid or liquid polymer composition containing unreacted monomers, a solvent, and / or by-products, the method comprising the steps of: supplying the composition to be defolazed to an inlet for the composition to be defolazed in a defolazing apparatus; drawing gas from the gas outlets of at least two containers; and drawing the defolazed composition from the outlet lines for the defolazed composition of at least two containers.

[0037] Favorable results are particularly obtained when the defolatorial apparatus comprises three containers, with the first and second containers each having a recirculation line connecting them back to their respective containers from an outlet line for the defolatorialized composition.

[0038] The recirculation ratio of the first and second containers depends on the viscosity of the composition to be deflated, and whether the composition contains one or more volatile compounds, such as 1-butene, that have a low critical temperature and a low boiling point at operating pressure. According to the present invention, a low critical temperature and a low boiling point at operating pressure means a critical temperature and a low boiling point at operating pressure of less than 300°C, preferably less than 230°C. When compounds with a low critical temperature and a low boiling point at operating pressure are contained, a relatively high recirculation ratio is preferred.

[0039] Therefore, the ratio of liquid drawn from the outlet line for the defolatable composition in the first container and returned to the first container via the recirculation line, based on the total volume of liquid drawn from the outlet line for the defolatable composition in the first container, may be 0 to 80%. When this ratio is at least 0.25 to 85%, more preferably 50 to 80%, particularly good results are obtained.

[0040] Similarly, the ratio of liquid drawn from the outlet line for the defolatated composition of the second container and returned to the second container via the recirculation line, based on the total volume of liquid drawn from the outlet line for the defolatated composition of the second container, may be 0 to 80%. When this ratio is at least 0.25 to 85%, more preferably 50 to 80%, particularly good results are obtained.

[0041] The present invention is not specifically limited in terms of the type of composition to be deflated. For example, the method is particularly preferred when the composition to be deflated is selected from the group consisting of polycaprolactone, polyolefin elastomer, polylactic acid, polyglycolic acid, polyolefin, and mixtures or copolymers of two or more of the above-mentioned polymers.

[0042] The present patent application will then be described by reference to advantageous embodiments and the accompanying drawings. [Brief explanation of the drawing]

[0043] [Figure 1] This is a schematic cross-sectional view of a daphne apparatus according to one embodiment of the present invention. [Figure 2a] This figure shows four different types of static mixers that can be used in the devolatilization apparatus and method according to the present invention. [Figure 2b] This figure shows four different types of static mixers that can be used in the devolatilization apparatus and method according to the present invention. [Figure 2c] This figure shows four different types of static mixers that can be used in the devolatilization apparatus and method according to the present invention. [Figure 2d] This figure shows four different types of static mixers that can be used in the devolatilization apparatus and method according to the present invention. [Figure 2e] This figure shows four different types of static mixers that can be used in the devolatilization apparatus and method according to the present invention. [Modes for carrying out the invention]

[0044] For defolazing compositions containing volatile components, such as solid or liquid polymer compositions containing unreacted monomers, solvents, and / or by-products, the defolazing apparatus 10 shown in Figure 1 comprises three containers 12, 12', and 12”, each of which comprises a distributor 14, 14', and 14”, and internal structures 16, 16', and 16''', such as perforated trays, located below each of the distributors 14, 14', and 14”. Furthermore, each of the three containers 12, 12', and 12'' is equipped with gas outlets 18, 18', and 18''' and outlet lines 20, 20', and 20''' for the defolable composition. The outlet line 20 for the defolable composition of the first container 12 is connected to a recirculation line 22, and the outlet line 20' for the defolable composition of the second container 12' is connected to a recirculation line 22', while the outlet line 20' for the defolable composition of the third container 12'' is not connected to a recirculation line. In addition, the outlet line 20 for the defolable composition of the first container 12 is connected to a connection line 23 which leads to the inlet of the distributor 14' of the second container 12', and the outlet line 20' for the defolable composition of the second container 12' is connected to the third container 12 The connection line 23' is connected to the inlet of the distributor 14 of the second container 12', and the recirculation line 22' of the second container 12' is connected to the connection line 23 and combined with it to form the combined connection and recirculation line 24 of the second container 12', i.e., the inlet line 24. The recirculation line 22, when viewed upstream, comprises a preheater 25, a back pressure valve 26, and a static mixer 28, and the inlet line 29 for the composition to be defolated in the defolatorial device 10 is connected to the static mixer 28. Similarly, the inlet line 24 connected to the second container 12' comprises a static mixer 28', a preheater 25', and a static mixer 28'' when viewed upstream, and the connection line 23' comprises a preheater 25'' and a static mixer 28'''' when viewed upstream.

[0045] During the operation of the defoliator 10, compositions containing volatile components to be defoliated, such as solid or liquid polymer compositions containing unreacted monomers, solvents, and / or by-products, are continuously supplied to the static mixer 28 via the inlet line 29 for the defoliator composition of the defoliator 10, where the composition is mixed with the liquid portion that has been drawn out via the outlet line 20 of the first vessel 14 and recirculated through the recirculation line 22 through the preheater 25 and back pressure valve 26. The defoliator composition coming from the upstream polymerization reactor is usually a two-phase flow, while the defoliated flow that is recirculated is reheated in the preheater 25 to become a homogeneous phase utilizing the back pressure valve 26, which then changes back to a two-phase flow after passing through the back pressure valve 26 due to the pressure drop after the back pressure valve 26. The two flows are thoroughly mixed under high shear in the static mixer 28, which increases the formation of bubble nuclei and homogenizes the two flows with different solid components. The resulting mixture then flows to the distributor 14 in the first container 12, where the evaporated volatile substances are separated from the remaining liquid. The homogenized liquid falls and collects at the bottom of the first container 12. Most of the components of the composition to be deflated, which have a low critical temperature and a low boiling point at the operating pressure, are evaporated in the first container 12 due to the operating pressure and temperature regulated in the first container 12, and the flow rate of the recirculation flow and the temperature regulated by the preheater 25 are used to control the operating temperature in the first container 12. The portion of the liquid flow that is defolable in the first container 12, withdrawn from the first container 12 via the outlet line 20, and not recirculated back to the first container 12 via the recirculation line 22, is led via the connection line 23 and combined with the portion of the liquid recirculated from the second container 12' via the recirculation line 22', and then led through the static mixer 28', preheater 25', and static mixer 28'', and subsequently enters the distributor 14' of the second container 12'. Preheating in the preheater 25' and mixing carried out in the static mixers 18' and 28'' cause bubbles to develop and form in the volatile substances in the flow, and in addition, increases the mass transfer of volatile substances from the bulk liquid to the liquid surface, maximizing the gas-liquid interaction surface. The evaporated volatile substances are separated from the remaining liquid in the second container 12', and the flow rate of the recirculated flow and the temperature regulated in the preheater 25' are used to control the operating temperature in the second container 12'.More specifically, a polymer concentration of over 90% is achieved in the second container 12'. Furthermore, the second static mixer 28'' upstream of the distributor 14' allows for the omission of a back pressure valve required in prior art devolatilization devices, which leads to cost savings. The portion of the liquid flow that is devolatilized in the second container 12', drawn out of the second container 12' via the outlet line 20', and not recirculated via the recirculation line 22', is led through the connection line 23', through the preheater 25'' and static mixer 28'''', and then enters the distributor 14'' of the third container 12''. Preheating in the preheater 25'' and mixing carried out in the static mixer 28'''' cause bubbles to develop and form in the volatile substances in the flow, and in addition, increases the mass transfer of volatile substances from the bulk liquid to the liquid surface, maximizing the gas-liquid interaction surface. For low-viscosity polymer grades, volatile substances are removed in the static mixer 28''' with the assistance and increased foaming provided by the static mixer 28''', reaching equilibrium in the distributor 14'', while for high-viscosity polymer grades, volatile substances are removed from the liquid phase in the third container 12''. Finally, the pure defolatable polymer is drawn out of the defolatorial device 10 via the outlet line 20''.

[0046] Figure 2 shows five different types of static mixers usable in the devolatilization apparatus and method according to the present invention, namely, Figure 2a shows an X-shaped static mixer 28 equipped with a crossbar-shaped deflection means 30 having an X-shape in both plan and side views. Figure 2b shows a baffle plate-type static mixer 28 equipped with a longitudinal deflection means 30, while Figures 2c and 2d show static mixers 28 equipped with a curved deflection means 30. Figure 2e shows a combined static mixer 28 and heat transfer element equipped with a tubular heat transfer element 32 for transporting a heat transfer medium in a tube, such as the one marketed as SMR by Sulzer Chemtech Ltd, where the tubular heat transfer element 32 also functions as a deflection means for the liquid being transported outside the tubular heat transfer element. [Explanation of symbols]

[0047] 10 Devolatilization device 12 containers 12' container 12” container 14 Distributor 14' distributor 14” distributor 16 Internal Structures / Perforation Trays 16' Internal Structure / Perforation Tray 16'' Internal Structure / Perforation Tray 18 Gas outlet 18' Outlet for gas 18''' Outlet for gas 20. Outlet line for defoliated composition 20' Exit line for defoliated composition 20''' Outlet line for defoliated composition 22 Recirculation Line 22' Recirculation Line 23 connection lines 23' Connection Line 24 Combined connection and recirculation line / inlet line of the second vessel 25 Preheater 25' Preheater 25" Preheater 26 Back pressure valve 28 Static mixer 28' static mixer 28'' static mixer 28''' static mixer 29 Inlet line for the composition to be defoliated in the defoliation apparatus 30 Static mixer deflection means 32 Heat transfer elements of a static mixer

Claims

1. A defoliation apparatus (10) for defoliating a composition containing volatile components, such as for defoliating a solid or liquid polymer composition containing unreacted monomers, solvents, and / or by-products, wherein the defoliation apparatus (10) comprises an inlet for the composition to be defoliated and at least two containers (12, 12', 12") arranged in series with respect to at least two containers (12, 12', 12"), each of the at least two containers (12, 12', 12") comprising at least one distributor (14, 14', 14"), an outlet line (20, 20', 20") for the defoliated composition and an outlet (18, 18', 18") for gas, and at least one distributor (14, 14', 14") of the first most upstream of the at least two containers (12, 12', 12") comprising an inlet at its upstream end and an outlet at its downstream end, and at least Devaporation apparatus (10), wherein another static mixer (28, 28', 28'', 28''') is located directly upstream of the inlet of the distributor (14, 14', 14"), or downstream of the inlet of the distributor (14, 14', 14") but upstream of the outlet of the distributor (14, 14', 14"), the inlet for the composition to be deflated is connected to the at least one static mixer (28, 28', 28'', 28'''), and the outlet line (20, 20', 20") for the deflated composition of the first most upstream of the at least two containers (12, 12', 12") is connected to a recirculation line (22, 22') which leads to the at least one static mixer (28, 28', 28'', 28''') to which the inlet for the composition to be deflated is connected.

2. The defoliation apparatus (10) according to claim 1, wherein a preheater (25, 25', 25") is located in the recirculation line (22, 22') upstream of the at least one static mixer (28, 28', 28'', 28'''').

3. The daphne generator (10) according to claim 1 or 2, wherein a back pressure valve (26) is located in the recirculation line (22, 22') upstream of the at least one static mixer (28, 28', 28'', 28''').

4. The daphne apparatus (10) according to any one of claims 1 to 3, wherein the outlet line (20, 20', 20") for the daphne-de-vaphated composition of the first upstream container of the at least two containers (12, 12', 12") is connected to a connecting line (23, 23') leading to the inlet of the second next downstream container of the at least two containers (12, 12', 12").

5. The defoliation apparatus (10) according to claim 4, wherein the outlet line (20, 20', 20") for the defoliated composition of the second next downstream container (12, 12', 12") of the at least two containers (12, 12', 12") is connected to a recirculation line (22, 22') which leads to the connection line (23, 23').

6. The daphne generator (10) according to claim 4 or 5, wherein a static mixer (28, 28', 28'', 28'''), a downstream preheater (25, 25', 25"), and a downstream back pressure valve (26) and / or a static mixer (28, 28', 28'', 28''') are arranged on the connection line (23, 23'), and the static mixer (28, 28', 28'', 28''') is connected to the inlet of the at least one distributor (14, 14', 14") of the second container (12, 12', 12").

7. A defoliation apparatus (10) according to any one of claims 1 to 6, comprising a third downstream container (12, 12', 12") having at least one distributor (14, 14', 14"), an outlet line (20, 20', 20") for a defoliated composition, and an outlet (18, 18', 18") for a gas, wherein the outlet line (20, 20', 20") for the defoliated composition of the second container (12, 12', 12") is connected to a connecting line (23, 23') that leads to the inlet of the third downstream container (12, 12', 12").

8. The daphne generator (10) according to claim 7, wherein a preheater (25, 25', 25") and a back pressure valve (26) and / or static mixers (28, 28', 28'', 28'''') downstream thereof are arranged on the connection line (23, 23'), and the static mixers (28, 28', 28'', 28'''') are connected to the inlet of the at least one distributor (14, 14', 14") of the third container (12, 12', 12").

9. The davoltation apparatus (10) according to any one of claims 1 to 8, wherein at least one, preferably all, of the at least one static mixer (28, 28', 28'', 28''') is selected from the group consisting of an X-type static mixer, a vortex / spiral-type static mixer, a quattro-type static mixer, a baffle plate-type static mixer, a turbulator-strip-type static mixer, and any combination of two or more of the mixer types.

10. A daphne generator (10) according to any one of claims 1 to 9, wherein each of the at least two containers (12, 12', 12") comprises one distributor (14, 14', 14"), and preferably each of the at least one distributor (14, 14', 14") of each of the at least two containers (12, 12', 12") comprises a pipe or an upstream portion which is a pipe.

11. A polymer preparation plant comprising at least one polymerization reactor, the outlet of at least one of the at least one polymerization reactor, and at least one defoliation device (10) according to any one of claims 1 to 10.

12. A method for defoliating a composition containing volatile components, such as for defoliating a solid or liquid polymer composition containing unreacted monomers, solvents, and / or by-products, the method comprising: supplying the composition to be defoliated to the inlet for the composition to be defoliated of a defoliation apparatus (10) according to any one of claims 1 to 10; drawing gas from the outlets (18, 18', 18") for each of the at least two containers (12, 12', 12") for the gas; and drawing the defoliated composition from the outlet lines (20, 20', 20") for each of the at least two containers (12, 12', 12") for the defoliated composition.

13. The method according to claim 12, wherein the defoliation apparatus (10) comprises three containers (12, 12', 12"), and the first container and the second container (12, 12', 12") each comprises a recirculation line (22, 22') that connects back to the respective containers (12, 12', 12") from the outlet line (20, 20', 20") for the defoliated composition.

14. Based on the total volume of liquid drawn from the outlet line (20, 20', 20") for the defolatable composition from the first container (12, 12', 12"), the ratio of the liquid drawn from the outlet line (20, 20', 20") for the defolatable composition from the first container (12, 12', 12") and returned to the first container (12, 12', 12") via the recirculation line (22, 22') is 0 to 90%, preferably at least 0.25 to 85%, most preferably 50 to 80%, and / or the second The method according to claim 12 or 13, wherein the ratio of the liquid drawn from the outlet line (20, 20', 20") for the defolatable composition of the second container (12, 12', 12") and returned to the second container (12, 12', 12") via the recirculation line (22, 22') is 0 to 90%, preferably at least 0.25 to 85%, most preferably 50 to 80%, based on the total volume of liquid drawn from the outlet line (20, 20', 20") for the defolatable composition of the second container (12, 12', 12") and returned to the second container (12, 12', 12") via the recirculation line (22, 22') is 0 to 90%, preferably at least 0.25 to 85%, most preferably 50 to 80%.

15. The method according to any one of claims 12 to 14, wherein the composition to be deflated is selected from the group consisting of polycaprolactone, polyolefin elastomer, polylactic acid, polyglycolic acid, polyolefin, and a mixture or copolymer of two or more of the polymers.

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