MX2008004283A - Reactor with optimized internal tray design - Google Patents

Abstract

A system for processing large quantities of a reaction medium while maintaining the reaction medium in sheets. The system includes a reactor having a plurality of vertically-spaced downwardly-sloped trays over which the reaction medium flows while it is subjected to reaction conditions. The slope of the trays increases downwardly to accommodate for the increased viscosity of the reaction medium while the reaction medium flows downwardly through the reactor. An upper portion of the trays have a uni-directional configuration, while a lower portion of the trays have a bi-directional configuration. Further, the orientation of flow across the uni-directional trays is rotated by 90 degrees in at least one location as the reaction medium flows down the uni-directional trays.

Description

REACTOR WITH OPTIMIZED INTERNAL CHARGE DESIGN Field of the Invention The present invention relates generally to a reactor for processing a reaction medium having a viscosity that increases as the medium flows through the reactor. In another aspect, the present invention relates to a polymerization reactor having a plurality of vertically spaced inner trays on which a polymerization reaction medium flows while the degree of polymerization of the reaction medium is increased. BACKGROUND OF THE INVENTION In certain chemical processing schemes, it is desirable for chemical reactions to take place in a reaction medium flowing in one or more relatively thin sheets. In such a processing scheme, the reaction progresses over a prolonged period of time while the sheets of the reaction medium are exposed to the necessary reaction conditions. This type of process is particularly advantageous where the chemical reaction produces a gaseous reaction byproduct, and it is desirable to rapidly and completely decouple such a by-product from the reaction medium. For example, if the chemical reaction produced by the gaseous byproduct is reversible, the failure to properly decouple the byproduct could continue to arrest the desired reaction. When the reaction medium flows in one or more relatively thin sheets, the gaseous reaction byproduct can quickly escape from the reaction medium. Further, when the reaction medium flows into one or more relatively thin sheets, the hydrostatic pressure lowers over the bottom portion of the reaction medium minimizes the boiling suppression that can be exhibited when the reactions are run using relatively deep reaction means. Although carrying out chemical reactions in relatively thin sheets of a reaction medium has a number of advantages, this type of process also presents a variety of challenges. For example, because the thin sheets of the reaction medium require large amounts of surface area over which it flows, very large and / or numerous reactors may be required to produce commercial quantities of the reaction product. In addition, in many processes employing thin sheets of the reaction medium, the viscosity of the reaction medium changes as the reaction progresses. Thus, the viscosity of the final product can be much larger or much lower than the viscosity of the initial reaction medium. This changing viscosity of the reaction medium presents a variety of design changes because significant variations in the flow rate and / or depth of the reaction medium can be undesirable. An example of a common commercial process where it is desirable to carry out a chemical reaction in one or more relatively thin sheets of the reaction medium is in the step of "finishing" the production of polyethylene terephthalate (PET). During the PET finishing step, the polycondensation causes the degree of polymerization of the reaction medium to increase significantly also produces ethylene glycol, acetaldehyde and water as reaction byproducts. Typically, the degree of polymerization of the reaction medium introduced into the reactor / finishing zone is 20-60 while the degree of polymerization of the reaction medium / product leaving the finishing reaction is 80-200. This increase in the degree of polymerization of the reaction medium during finishing causes the viscosity of the reaction medium to increase significantly. In addition, since the polycondensation reaction associated with the PET finish is reversible, it is desirable to decouple the ethylene glycol reaction by-product from the reaction medium as rapidly and completely as possible. Thus, there is a need for a more efficient and economical reactor that facilitates the processing of large quantities of the reaction medium in relatively thin sheets for extended periods of time. In addition, there is a need for a reactor more efficient and effective PET finishing that facilitates the polycondensation of large quantities of the reaction medium flowing in relatively uniform, thin sheets through the finishing reactor, while providing adequate residence time to achieve the necessary degree of polymerization. BRIEF DESCRIPTION OF THE INVENTION In accordance with one embodiment of the present invention, there is provided a reactor comprising a plurality of vertically spaced unidirectional inclined trays and a plurality of vertically spaced bi-directional inclined trays, wherein the inclination of the unidirectional trays is increased downwardly. . In accordance with another embodiment of the present invention, a reactor for processing a reaction medium is provided. The reactor comprises a plurality of vertically spaced inclined trays. At least some of the trays include an upwardly extending weir on which at least a portion of the reaction medium flows in order to pass to the next tray located immediately below it. According to yet another embodiment of the present invention, a polymerization process is provided which comprises: (a) introducing a medium of reaction in a polymerization reactor comprising a plurality of vertically spaced inclined trays; (b) causing the reaction medium to flow down into the polymerization reactor on the vertically spaced trays, wherein the average thickness of the reaction medium flowing over the vertically spaced trays is maintained at about 2.5 inches or more; and (c) removing the reaction medium from the polymerization reactor, wherein the degree of polymerization of the reaction medium removed from the polymerization reactor is at least about 25 percent greater than the degree of polymerization of the reaction medium introduced into the polymerization reactor. polymerization reactor. According to yet another embodiment of the present invention, there is provided a process comprising: (a) introducing a reaction medium into a top section of a reactor comprising a plurality of unidirectional inclined trays and a plurality of bidxre cially inclined trays; (b) causing the reaction medium to flow down into the reactor on unidirectional and bidirectional trays; and (c) withdrawing the reaction medium from a lower section of the reactor. BRIEF DESCRIPTION OF THE DRAWING FIGURES FIG. 1 is a sectional front view of a reactor for processing a reaction medium flowing towards down through it particularly illustrating the reactor as including two tray boxes housing each plurality of vertically spaced inclined inner trays on which the reaction medium flows as it passes down through the reactor. FIG. 2a is a sectional top view of the reactor taken along the line 2a-2a in FIG. 1, which particularly illustrates the longitudinal direction of the flow of the reaction medium on the top of the unidirectional tray. FIG. 2b is a sectional top view of the reactor taken along line 2b-2b in FIG. 1, which particularly illustrates the longitudinal direction of the flow of the reaction medium on the unidirectional tray located just below the tray shown in FIG. 2a. FIG. 3a is a sectional top view of the reactor taken along line 3a -3a in FIG. 1, which particularly illustrates the direction in the direction of the flow width of the reaction medium on a unidirectional tray located below the longitudinal trays illustrated in FIGS. 2a and 2b. FIG. 3b is a sectional top view of the reactor taken along the line 3b-3b in FIG. 1, that particularly illustrates the direction in the direction of the flow width of the reaction medium on the unidirectional tray located just below the tray shown in FIG. 3a. FIG. 4a is a sectional top view of the reactor taken along line 4a-4a in FIG. 1, which particularly illustrates the direction of flow of the reaction medium on a bidirectional roof tray that diverges down located below the unidirectional trays. FIG. 4b is a sectional top view of the reactor taken along line 4b-4b in FIG. 1, which particularly illustrates the direction of flow of the reaction medium on a downstream converging bidirectional conduit tray located just below the roof tray shown in FIG. 4a. FIG. 5a is an enlarged front view of the pair of longitudinal unidirectional trays circumscribed with shaded lines and marked "5" in FIG. 1. FIG. 5b is a side view of the longitudinal unidirectional trays shown in FIG. 5a. FIG. 6a is an enlarged front view of the pair of unidirectional trays in the width direction circumscribed with shaded lines and marked "6" in FIG. 1.

FIG. 6b is a side view of the unidirectional trays in the direction of the width shown in FIG. 6a. FIG. 7a is an enlarged front view of the pair of bidirectional trays circumscribed with shaded lines and marked "7" in FIG. 1. FIG. 7b is a side view of the bidirectional trays shown in FIG. 7a. FIG. 8a is an enlarged front view of the transition assembly circumscribed with shaded lines and marked "8" in FIG. 1. FIG. 8b is a top view of the transition assembly shown in FIG. 8a. FIG. 9 is a sectional front view of a reactor constructed in accordance with a first alternative embodiment of the present invention, which particularly illustrates that the reactor has only a single tray box disposed therein. FIG. 10 is a sectional top view of the alternative reactor taken along the line 10-10 in FIG. 9, which particularly illustrates the manner in which the individual tray box is placed in the reactor. FIG. 11 is a sectional front view of a reactor constructed in accordance with a second alternative embodiment of the present invention, illustrating particularly that the reactor has three boxes of trays placed therein. FIG. 12 is a sectional top view of the alternative reactor taken along line 12-12 in FIG. 1, which particularly illustrates the manner in which the three tray boxes are placed in the reactor. FIG. 13 is a sectional top view of the reactor constructed in accordance with a third alternative embodiment of the present invention, which particularly illustrates that the reactor has 6 tray boxes placed side by side in the reactor. FIG. 14 is a side view of a series of unidirectional trays constructed in accordance with an alternative embodiment of the present invention, which particularly illustrates that a space may be formed on the back of the unidirectional trays to allow a portion of the reaction medium to overflow the back of a tray and fall to the next lower tray. Detailed Description of the Invention With reference initially to FIG. 1, a reactor 20 is illustrated as comprising a container shell 22, a distributor 24, and two tray boxes 26a, b. The tray shell 22 preferably has a generally cylindrical, elongated configuration. The length to diameter ratio (L: D) of the tray shell 22 is preferably at least about 1: 1, more preferably in the range of about 2: 1 to about 30: 1 and most preferably in the range of 3: 1 to 10: 1. During the normal operation of the reactor 20, the tray armor 22 is maintained in a substantially vertical position. The tray armor 22 defines an upper inlet 28 and a lower outlet 30. The distributor 24 and the tray boxes 26a, b are placed vertically between the inlet 28 and the outlet 30 so that the reaction medium entering the reactor 20 through the entrance 28 can flow down through the distributor 7? and the tray boxes 26a, b before being discharged from the reactor 20 via the outlet 30. When the reactor 20 includes a plurality of tray boxes 26a, b, the distributor 24 is used to divide and distribute the flow of the container. incoming reaction medium so that each box of trays 26a, b receives and processes substantially the same amount of the reaction medium. If the reactor 20 where only one tray of trays is used, then the distributor would not divide the flow of the reaction medium, but would still act to properly distribute the reaction medium at the entrance of the tray box. In the modality illustrated in the E'IGS. 1-8, the reactor 20 includes two substantially identical tray boxes 26a, b. The following section will describe the configuration of only one tray case 26a with the understanding that all tray boxes 26a, b, have substantially the same configuration. With reference to FIGS. 1 and 2a, the box of trays 26a includes a plurality of vertical side walls 27a, b, c, d that define a generally rectangular internal space. The box of trays 26a also includes a plurality of vertically spaced inclined trays received in the internal space and rigidly coupled to the side walls 26a, b, c, d. The internal space defined by the side walls 27a, b, c, d is open at the top and bottom so that the reaction medium can enter the top of the tray box 26a, flow down through the internal space on the inclined trays, and exit the bottom of the tray box 26a. Preferably, the box of trays 26a includes at least about 10 trays, more preferably at least about 20 trays, and much more preferably in the range of 30 to 100 trays. Of course, the preferred total number of trays in the reactor 20 is simply the number of trays in a tray box at times the number of tray boxes in the reactor 20. The tilt of the trays it generally increases downwardly in the reactor 20 to accommodate the increase viscosity of the reaction medium as it flows down onto the trays. With reference again to FIG. 1, it is preferred that the box of trays 26a include trays with different configurations and / or orientations to optimize the flow of the reaction medium therethrough. Preferably, the tray box 26a includes a plurality of unidirectional trays 32 and a plurality of bidirectional trays 34. As used herein, the term "unidirectional tray" means a tray that slopes in only one direction so that the fluid that Flow in the box of trays in the elevation of that tray flow only in one direction. As used herein, the term "bi-directional tray" means a tray that slopes in two directions so that fluid flowing in the tray of trays at the elevation of those trays flows in two directions. In a preferred embodiment of the present invention, at least a portion of the unidirectional trays 32 is located above at least a portion of the bidirectional trays 34. Most preferably, all unidirectional trays 32 are located above all trays bidirectional 34. Preferably, the box of trays 26a includes at least about 5 unidirectional trays, plus preferably at least about 10 unidirectional trays, and much more preferably in the range of 15 to 50 unidirectional trays. Preferably, the tray box 26a includes at least about two bidirectional trays, more preferably at least about 10 bidirectional trays, and most preferably in the range of 15 to 50 bidirectional trays. Preferably, at least about 10 percent of all trays in the tray box 26a are unidirectional trays, more preferably at least about 20 percent are unidirectional trays, and most preferably in the range of 30 percent to 80 percent. One hundred are unidirectional trays. Preferably, at least about 1 percent of all the trays in the tray box 26a are bidirectional trays, more preferably at least about 20 percent are bidirectional trays. As illustrated in the IJ'IG. 1, the tray box 26a preferably includes an upper assembly 36 and a lower assembly 38 of unidirectional trays 32. The upper assembly 36 of unidirectional trays 32 preferably includes a plurality of longitudinal inclined trays 40. The lower assembly 38 of the unidirectional trays 32 preferably includes a plurality of trays inclined in the width direction 42. As shown in the arrows in FIGS. 2 and 3, it is preferred for each unidirectional tray 32 to be elongated with the inclined longitudinal trays 40 (FIG 2) which is inclined in the direction of the elongation of the tray, while the trays inclined in the width direction 42 (FIG.3) are inclined perpendicular to the direction of elongation of the tray. As illustrated in FIGS. 2 and 3, the directions of the inclination of the longitudinal inclined trays 40 and the trays inclined in the direction of the width 42 are substantially perpendicular to each other. As illustrated in FIGS. 1, 2 and 5, the vertically adjacent longitudinal inclined trays 40a, b are inclined in the generally opposite directions so that the reaction medium is brought to flow forward and backward on the longitudinal inclined trays 40 as it progresses downwards in the reactor 20. As illustrated in FIGS.2 and 5, each longitudinal sloped tray 40 includes a substantially rectangular, substantially planar main member 44 and a weir 46. In the embodiment illustrated in FIGS. main member 44 are preferably coupled to and sealed along three of the four side walls 27 of the tray box 26a, while a space 47 (FIG. 2a, b) 5b) is formed between the fourth side of the main member 44 and the remaining wall 27 of the tray box 26a. The space 47 provides a passage through which the reaction medium can fall down onto the next lower longitudinal sloping tray 40. The main member 44 is tilted downward so that the reaction medium can flow by gravity towards the landfill 46. The downward inclination of the main member 44 is preferably in the range of about 0.5 to about 10 degrees from the horizontal, most preferably in the range of 1 to 4 degrees from the horizontal. With reference again to the F'IGS. 2 and 5, the main member 44 has a downward facing surface, generally flat. The main member 44 preferably has substantially no holes therein so that all of the liquid flowing over the tray 40 must pass over / through the weir 46 in order to leave the tray 40. The weir 46 extends upwards from the upper surface of the main member 44 near the lower elevation of the main member 44. Preferably, the weir 46 is spaced less than about 6 inches from the terminal edge of the main member 44, more preferably less than about 3 inches, and much more preferably lower that 2 inches. Preferably, the weir 46 extends completely along the width of the longitudinal inclined tray 40 of the side wall 27a to the side wall 27c. The weir 46 helps to maintain a substantially uniform sheet of reaction medium on the tray 40. Preferably, the weir 46 has a height of at least about 2.5 inches. More preferably, the height of the weir 46 is in the range of 3 to 12 inches. As illustrated in FIG. 5a, a plurality of relatively small relatively small landfill orifices 48 are preferably formed near the bottom of the landfill 46, adjacent to the main member 44. The landfill orifices 48 allow a relatively small amount of the reaction medium to flow through them. during the normal operation of the reactor 20. During the period of the reactor 20, the landfill orifices 48 allow substantially all of the reaction medium to be drained from the trays 40, so that an accumulation of the reaction medium does not remain trapped behind from landfill 46 when reactor 20 is turned off. As illustrated in FIGS. 1, 3 and 6, trays inclined in the direction of the vertically adjacent widths 42a, b are inclined in generally opposite directions so that a reactor means is brought to flow forward and back on the trays inclined in the direction of the width 42 as it progresses downwards in the reactor 20. As illustrated in FIGS. 3 and 6, each tray inclined in the width direction 42 includes a substantially rectangular substantially flat main member 50 and a weir 52. Three sides of the main member 44 are coupled to and sealed along three of the four walls sides 27 of the tray box 26a, while a space 53 (FIGS 3a, b and 6a) are formed between the four sides of the main member 50 and the remaining side wall 27 of the tray box 26a. The space 53 provides a passage through which the reaction medium can fall downward onto the next tray inclined in the direction of the lower width 42. The main member 50 is inclined so that the reactor medium can flow downwards by gravity towards the landfill 52. The downward inclination of the trays inclined in the direction of the width 42 increases downwards in the reactor 20. Preferably, the much more upper part of one of the trays inclined in the direction of the width 42 has an inclination towards down in the range of about 0.5 to about 10 degrees from the horizontal, much more preferably in the range of 1 to 4 degrees from the horizontal. Preferably, the much lower part of one of the trays inclined in the direction of the width 42 has a downward tilt in the range of about 2 to about 20 degrees from the horizontal, much more preferably in the range of 4 to 10 degrees from the horizontal. Preferably, the downward inclination of the much lower part of one of the trays inclined in the direction of the width 42 is at least about 1 degree greater than the downward inclination of the much larger part of one of the inclined trays in the width direction 42, more preferably at least about 2 degrees greater than the downward inclination of the much higher part of one of the trays inclined in the width direction 42, and most preferably in the range of 4 to 10 degrees greater than the downward inclination of the much higher part of one of the trays inclined in the width direction 42. Referring again to FIGS. 3 and 6, the main member 50 preferably has substantially no holes therein so that all the liquid flowing over the tray 42 must pass over / through the weir 52 in order to leave the tray 42. The main member 50 presents an upper surface of confrontation generally downwards. The weir 52 extends upwardly from the upper surface of the main member 50 near the lower elevation of the main member 50. Preferably, the weir 52 is spaced from the terminal edge of main member 50 by a distance of less than about 6 inches, more preferably less than about 3 inches, and much more preferably less than 1 inch. Preferably, the weir 52 extends completely between the side wall 27b and the side wall 27d. The weir 52 helps to maintain a substantially uniform sheet of reaction medium on the tray 42. Preferably, the weir 52 has a height of at least about 2.5 inches. More preferably, the height of the weir 52 is in the range of 3 to 12 inches. As illustrated in FIG. 6b, a plurality of relatively small landfill orifices 54 are preferably formed near the bottom of the weir 52, adjacent to the main member 50. The landfill orifices 54 allow a relatively small amount of the reaction medium to flow therethrough during the normal operation of the reactor 20. During the stoppage of the reactor 20, the orifices of the weir 54 allow all of the reaction medium to be drained from the trays 42, so that an accumulation of the reactor medium does not remain trapped within the weir 52 when the reactor 20 is off. In one embodiment of the present invention, at least 5 of the unidirectional trays 32 are equipped with a landfill, more preferably at least 10 of the Unidirectional trays 32 are equipped with a landfill. Preferably, at least 10 percent of all the unidirectional trays 32 in the tray box 26a are equipped with a weir, more preferably at least 33 percent of the unidirectional trays 32 are equipped with a weir, and most preferably by At least 66% of the unidirectional trays 32 are equipped with a landfill. The landfill can help to provide more residence time in the inventive reactor than in conventional designs, to require equivalent or less reactor volume, trays and / or metal surfaces. In addition, landfills can help provide a thicker sheet of reaction medium on the trays than conventional PET terminator designs. Also, it should be noted that the embodiments described herein advantageously provide thinner sheets of the reaction medium that fall down from tray to tray and thicker sheets of the reaction medium on the trays. As illustrated in FIGS. 1, 4 and 7, the bidirectional trays 34 are coupled and extend between the side walls 27b, d of the tray 26a. Bidirectional trays 34 include alternating roof trays 34a and conduit trays 34b. As perhaps best illustrated in Figures 4a and 7b, each tray will bidirectional roof 34a includes a vertical divider member 56 and a pair of downward sloping roof members 58, 60 extending in generally opposite directions from the bottom of divider member 56. Roof members 58, 60 diverge from each other since they extend downwards and outwards from the dividing member 56. A first space 62 is formed between the terminal edge of the roof member 58 and the side wall 27a. A second space 54 is formed between the terminal edge of the roof member 60 of the side wall 27c. The reaction medium flows down through the spaces 62, 64 in order to reach the next lower bidirectional conduit tray 34b. With reference now to the F1GS. 4b and 7a, each bidirectional conduit tray 34b includes a pair of downwardly inclining duct members 66, 68 engaged and extending inwardly of the side walls 27a, c of the tray box 26a. The conduit members 66, 68 converge towards each other as they extend downwardly and inwardly of the side walls 27a, c. A space 70 is formed between the lower end edges of the conduit members 66, 68. The space 70 is large enough to allow separate sheets of the reaction medium to flow over the conduit members 66, 68. to remain separated as they fall through space 70 to the next lower roof tray 34a. The separate portions of the reaction medium flowing on the duct members 66, 68 fall downwardly of the space 70 on opposite sides of the divider member 56 of the next lower roof tray 34a. In a preferred embodiment of the present invention, the inclination of the bidirectional trays 34 increases downwardly in the reactor 20. Preferably, the much more superior part of one of the bidirectional trays 34 has a downward inclination in the range of about 0.5. about 10 degrees from the horizontal, much more preferably in the range of from 1 to 4 degrees from the horizontal. Preferably, the much lower part of one of the bidirectional trays 42 has a downward inclination in the range of about 5 to about 40 degrees from the horizontal, most preferably in the range of 10 to 25 degrees from the horizontal. Preferably, the downward inclination of the much lower part of one of the bidirectional trays 34 is at least about 2 degrees greater than the downward inclination of the much larger part of one of the bidirectional trays 34, more preferably at less approximately 4 degrees greater than the downward inclination of the much higher part of one of the bidirectional trays 34, and much more preferably in the range of 6 to 20 degrees greater than the downward inclination of the much higher part of one of the bidirectional trays 34. Referring now to FIGS. 1 and 8, a transition member 72 is used to pass the flow of the reaction medium from the single sheet flow over the unidirectional trays 32 to the double sheet flow over the bidirectional trays 34. The transition member 74 engages and extends between the side walls 26b, d of the tray box 26a. The transition member 74 includes an upper distribution tank 76 and a lower distribution tray 78. The distribution tank 76 is operable to receive the reaction means of the much lower unidirectional tray 32 and divide the reaction medium into two portions. substantially the same. The two equal portions of the reaction medium are discharged from the bottom of the distribution tank 76 onto the separated diverging sections 80a, b of the distribution tray 78. In the same way, the subsequent divisions in the flow leaving the bidirectional trays towards down are possible using similar distribution boxes. In this way, multiple bidirectional routes can be created if required by viscosity, flow velocity and liquid depth targets. The distribution tank 76 includes a pair of tilting side walls 82a, b converging downward toward each other. A divider line 84 is defined at the location where the side walls 82a, are joined together. A plurality of first holes 86a is defined in the side wall 82a next to the divider line 84. A plurality of second holes 86b is defined in the side wall 82b close to the divider line 84. Preferably, the transition member 78 includes a total of at least about 10 holes 86a, b. As best illustrated in FIG. 8b, the first and second holes 86a, b are located on opposite sides of the divider line 84. Preferably, the cumulative open area defined by the first orifices 86a is substantially equal to the cumulative open area defined by the second orifices 86b, so that equal amounts of the reaction medium will automatically flow through the first and second orifices 86a, b. The first holes 86a are aligned on the first section 80a of the distribution tray 78, while the second holes 86b are aligned on the second section 80b of the distribution tray 78. As shown in FIGS. 8a, b, the end edges of the first and second inclination sections 80a, b of the dispensing tray 78 are spaced apart from the side walls 27a, c so that the spaces 88a, b form between them. The two substantially equal portions of the reaction medium discharged from the distribution tank 76 flow onto the diverging downward inclination sections 80a, b of the distribution tray 78 towards the spaces 88a, b. The separated portions of the reaction medium then fall out of the distribution tray 78, through the spaces 88a, b and onto the much more highly convergent bidirectional tray 1, 34b. As mentioned in the above, the two substantially equal portions of the reaction medium are then kept separate as they flow down onto the bidirectional trays 34. Referring now to the F1GS. 9 and 10, a first alternative reactor design is illustrated. The alternative reactor 100 includes only an individual tray box 102. This design has the advantage of not being needed for feeding equally among the multiple tray boxes. Thus, the construction of the distributor 104 is simplified. Also, the total number of trays, distribution of different types of trays, number or landfills, location of the landfills, and inclination of the trays in the reactor 100 are different than that of the reactor 20 (FIGS 1.8). These differences illustrate that it may be desirable to vary the design of the reactor to meet the particular process requirements within which it is implemented. However, all designs disclosed herein are within the scope of the present invention. With reference now FIGS. 11 and 12, a second alternative reactor design is illustrated. Alternative reactor 200 includes three tray boxes 202a, b, c. With reference now FIG. 13, a third alternative reactor design is illustrated. The alternative reactor 300 includes six cases of trays 302. This design has the advantage of using more space within the reaction vessel, thus the size of the reaction vessel can be reduced. With reference now to FIG. 14, an alternative unidirectional tray design is illustrated. The unidirectional trays 400 illustrated in FIG. 14 are similar to those illustrated in FIGS. 5 and 6, but are configured to provide a space 402 between the rear 404 of each unidirectional tray 400 and the nearest side wall 406 of the tray box. It should be understood that the side wall 406 need not be a wall of the tray box with the trays 400 that are associated; rather, the side wall 406 may be the wall of another tray box or the wall of the reactor vessel. As illustrated in FIG. 14, this space 402 between the rear portion 404 of each tray 400 and the nearest side wall 406 permits a portion of the reaction medium. processed back 408 overflow from the rear 404 of the tray 400 and fall downward from the next lower tray 400. In order to provide a sufficiently large orifice for the passage of the overflow reaction means 408, it is preferred for the space 402 between the back 404 of the trays 400 and the nearest side wall 406 having an average width of at least about 1 inch, more preferably in the range of about 1.5 to about 12 inches, and much more preferably in the range of 2 to 8 inches. In the embodiment illustrated in FIG. 14, it is preferred that the rear portion 404 of each unidirectional tray 400 includes a rounded bottom edge 410 which allows the overflow reaction 408 to "adhere" to the upper tray 400 until it is positioned over at least a portion of the container. next lower tray 400. Once positioned on the next lower tray 400, the reaction medium 408 drops from the upper tray -400 the lower tray 400, where it recombines with a portion of the reaction medium 408 that flowed over the edge. terminal 412 of the upper tray 400 and on the lower tray 400. In order to allow the overflow reaction means to adhere to the upper tray 400 until it is positioned on the lower tray 400, it is preferred for the lower edge rounded 410 of the unidirectional trays 400 having a minimum radius of curvature of at least 1 inch, more preferably in the range of about 1.5 to about 12 inches, and most preferably in the range of 2 to 8 inches. It should also be noted that the embodiment illustrated in FIG. 14 uses unidirectional trays 400 without landfills. Thus, the terminal edges 412. of the trays 400 illustrated in FIG. 14 are defined by an edge of the substantially flat main member 414 of the trays 400, rather by the upper edge of a weir. However, it is contemplated that the overflow design of the back illustrated in FIG. 14 is also suitable for use with trays that have landfills. The reactors illustrated in FIGS. 1-14 can be used in a different process variety. These reactors are particularly useful in processes where it is advantageous for chemical reactions to take place in relatively thin sheets of a reaction medium. In addition, these reactors are designed to accommodate the situation where the viscosity of the reaction medium increases during processing. In a preferred embodiment of the present invention, the dynamic viscosity (measured in poise) of the reaction medium leaving the reactor is at least about 50% greater than the viscosity dynamics of the reaction medium entering the reactor, more preferably at least about 250 percent greater than the dynamic viscosity of the reaction medium entering the reactor, and much more preferably 1,000 percent greater than the dynamic viscosity of the reaction medium that enters the reactor. Preferably, the reactant (s) described in the foregoing are polymerization reactors, used to process a reaction medium that is subjected to polymerization. In a particularly preferred process, the reactor is used in a process for producing polyethylene terephthalate (PET). In such a process, the reaction medium entering the reactor preferably has a degree of polymerization (DP) in the range of about 20 to about 75, more preferably in the range of about 35 to about 60, and most preferably in the range from 40 to 55. As used herein, "degree of polymerization" or "DP" means the number-average degree of polymerization, which is defined as the number-average polymer molecular weight divided by the repeating unit molecular weight. . As the reaction medium flows down through the reactor, the DP of the reaction medium increases due to polycondensation. Preferably, the DP of the reaction medium leaving the reactor is at least about 25 percent greater than the DP of the medium of reaction entering the reactor, more preferably in the range of about 50 to about 500 percent greater than the DP of the reaction medium entering the reactor and much more preferably in the range of 80 to 400 percent greater than the DP reaction medium entering the reactor. Preferably, the reaction medium leaving the reactor has a DP in the range of about 75 to about 200, more preferably in the range of about 90 to about 180 and most preferably in the range of 105 to 165. In a preferred embodiment of the present invention, the reaction conditions in the reactor are maintained at a temperature in the range of about 250 to about 325 ° C and at a pressure in the range of about 0.1 to about 4 torr, more preferably at a temperature in the range from about 270 to about 310 ° C and a pressure in the range of from about 0.2 to about 2 torr, and most preferably at a temperature in the range of 275 to 295 ° C and a pressure in the range of from 0.3 to about 1.5 torr. . The average residence time of the reaction medium in the reactor is preferably in the range of about 0.25 to about 25 hours, much more preferably in the range of 0.5 to 2.5 hours.

The configuration of the reactor described in the foregoing with reference to FIGS. 1-14 is preferably operable to maintain an average depth of reaction medium on the trays of at least about 2.5 inches, much more preferably in the range of 3 to 12 inches. The inventors note that for all the numerical ranges provided herein, the upper and lower ends of the intervals may be independent of each other. For example, a numerical range of 10 to 100 means greater than 10 and / or less than 100. Thus, a range of 10 to 100 provides support for a claim limitation of greater than 10 (without the upper limit), a limitation of claim of less than 100 (without the lower limit) as well as the complete range of 10 to 100 (with both upper and lower limits). The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be made within the spirit and scope of the invention.

Claims (64)

1. CLAIMS 1. A reactor, characterized in that it comprises: a plurality of vertically spaced unidirectional inclined trays and a plurality of bi-directionally inclined, vertically spaced trays, wherein the inclination of the unidirectional trays increases downwards.
2. 2. The reactor according to claim 1, characterized in that the inclination of the bidirectional trays increases downwards.
3. The reactor according to claim 1, characterized in that at least a portion of the unidirectional trays are located above at least a portion of the bidirectional trays.
4. The reactor according to claim 1, characterized in that the unidirectional trays are located above all bidirectional trays.
5. 5. The reactor according to claim 1, characterized in that the adjacent ones of the unidirectional trays are inclined in opposite directions.
6. The reactor according to claim 1, characterized in that the bidirectional trays include roof and duct trays alternating, wherein the roof trays include a pair of downwardly diverging roof members, wherein the conduit trays include a pair of downward converging conduit members.
7. The reactor according to claim 1, characterized in that the plurality of unidirectional trays includes a top group of unidirectional trays that are tilted back and forth in a first direction and a lower group of unidirectional trays that are tilted forward and forward. backward in a second direction, wherein the first and second directions are substantially perpendicular to each other.
8. The reactor according to claim 1, characterized in that at least 10 percent of all the trays in the reactor are unidirectional trays and at least 10 percent of all the trays in the reactor are bidirectional trays.
9. 9. The reactor according to claim 1, characterized in that the inclination of the unidirectional trays varies by at least about 2 degrees, wherein the inclination of the bidirectional trays varies by at least about 4 degrees.
10. 10. The reactor in accordance with claim 1, characterized in that the unidirectional trays include a substantially planar main member having a sloping face facing down, the main member having substantially no orifices therein.
11. The reactor according to claim 10, characterized in that at least a portion of the unidirectional trays include a landfill coupled to the main member, and extending upward from the sloping facing surface downwardly.
12. The reactor according to claim 11, characterized in that the weir has a height of at least about 2.5 inches.
13. The reactor according to claim 11, characterized in that at least 10 percent of all unidirectional trays are equipped with landfills, where the landfills have a height in the range of 3 to 12 inches.
14. The reactor according to claim 1, characterized in that the reactor includes a transition member placed below the unidirectional trays and above the bidirectional trays, wherein the transition member defines a divider line, a first group of located holes. on one side of the dividing line and a second group of holes located on the other side of the dividing line, wherein the cumulative open area defined by the first group of holes is substantially the same as the cumulative open area defined by the second group of holes.
15. 15. The reactor according to claim 14, characterized in that the transition member includes a pair of downward converging walls converging towards the dividing line, wherein the first and second groups of holes are located proximate the bottom of the converging down walls.
16. 16. The reactor according to claim 1, characterized in that at least one portion of the unidirectional trays have a trailing end and a terminal end wherein the trailing and terminal ends are located on the generally opposite ends of the unidirectional trays, wherein the tray slopes down the rear end to the terminal end, wherein the reactor defines a rear opening located adjacent to the trailing end and a terminal opening located adjacent to the trailing end and a terminal opening located adjacent to the trailing end 1.
17. 17. A reactor for processing a reaction medium, the reactor characterized in that it comprises: a plurality of vertically spaced inclined trays, wherein at least some of the trays include an upwardly extending weir on which at least a portion of the reaction medium flows to pass in order to pass to the next tray located immediately below the same .
18. 18. The reactor according to claim 17, characterized in that the weir has a height of about 2.5 inches.
19. 19. The reactor according to claim 17, characterized in that the weir has a height in the range of 3 to 12 inches.
20. 20. The reactor according to claim 17, characterized in that at least 10 percent of all trays are equipped with the landfill.
21. 21. The reactor according to claim 17, characterized in that the trays include a plurality of unidirectional trays.
22. 22. The reactor according to claim 21, characterized in that the adjacent ones of the unidirectional trays are inclined in opposite directions.
23. 23. The reactor according to claim 22, characterized in that the inclination of the Unidirectional trays are increased downwards.
24. 24. The reactor according to claim 21, characterized in that the trays include a plurality of bidirectional trays.
25. 25. The reactor according to claim 24, characterized in that the bidirectional trays include alternating roof and duct trays, wherein the roof trays include a pair of downwardly diverging roof members, wherein the conduit trays include a pair of duct members converging downwards.
26. 26. The reactor according to claim 25, characterized in that the inclination of the bidirectional trays increases downwards.
27. 27. The reactor according to claim 24, characterized in that the bidirectional trays are located below the unidirectional trays.
28. 28. The reactor according to claim 24, characterized in that it includes at least 5 of the unidirectional trays and at least 5 of the bidirectional trays.
29. 29. The reactor according to claim 17, characterized in that at least a portion of the inclined trays have one end back, where the trays are tilted down the back end to the weir, where the reactor defines a trailing space located adjacent to the trailing end, where at least a portion of the reaction medium flows over the trailing end and down to the trailing end. through the back space in order to move to the next tray located immediately below it.
30. 30. A polymerization process, characterized in that it comprises: (a) introducing a reaction medium into a polymerization reactor comprising a plurality of vertically spaced inclined trays; (b) causing the reaction medium to flow down into the polymerization reactor on the vertically spaced trays, wherein the average thickness of the reaction medium flowing over the vertically spaced trays is maintained at about 2.5 inches or more; and (c) removing the reaction medium from the polymerization reactor, wherein the degree of polymerization (OD) of the reaction medium removed from the polymerization reactor is at least about 25 percent greater than the DP of the reaction medium introduced into the polymerization reactor. the polymerization reactor.
31. 31. The polymerization process according to claim 30, character.! because the average thickness of the reaction medium flowing over the vertically spaced trays is maintained in the range of 3 to 12 inches.
32. 32. The polymerization process according to claim 30, characterized in that the DP of the reaction medium introduced into the polymerization reactor is in the range of about 20 to about 75.
33. The polymerization process according to claim 30, characterized in that the reaction medium withdrawn from the polymerization reactor comprises polyethylene terephthalate (PET).
34. 34. The polymerization process according to claim 30, characterized in that the reaction medium is maintained at a temperature in the range of about 250 to about 325 ° C and at a pressure in the range of about 0.1 to about 4 torr in the polymerization reactor.
35. 35. The polymerization process according to claim 30, characterized in that at least some of the trays include an upwardly extending weir on which at least a portion of the reaction medium flows in order to pass to the next tray located immediately next to it.
36. 36. The polymerization process according to claim 35, characterized in that the landfill has a height of at least about 2.5 inches
37. 37. The polymerization process according to claim 35, characterized in that at least 10 percent of all the trays are equipped with the landfill.
38. 38. The polymerization process according to claim 30, characterized in that the trays include a plurality of unidirectional trays.
39. 39. The polymerization process according to claim 38, characterized in that the adjacent ones of the unidirectional trays are inclined in opposite directions.
40. 40. The polymerization process according to claim 39, characterized in that the inclination of the unidirectional trays increases downwards.
41. 41. The polymerization process according to claim 38, characterized in that the trays include a plurality of bidirectional trays.
42. 42. The process according to claim 41, characterized in that the bidirectional trays include alternating roof and duct trays, wherein the roof trays include a pair of downwardly diverging roof members, wherein the duct trays include a pair of duct members converging downwards.
43. 43. The polymerization process according to claim 42, characterized in that the inclination of the bidirectional trays increases downwards.
44. 44. The polymerization process according to claim 41, characterized in that the inclination of the bidirectional trays are located below the unidirectional trays.
45. 45. The polymerization process according to the rei indication 41, characterized in that the reactor includes at least 5 of the unidirectional trays and at least 5 of the bidirectional trays.
46. 46. The polymerization process according to claim 30, characterized in that the trays include a plurality of unidirectional trays, wherein the process further comprises causing at least a portion of the reaction medium to flow simultaneously on two generally opposite ends of minus one of the unidirectional trays.
47. 47. The polymerization process according to claim 46, characterized in that the generally opposite ends of the unidirectional trays are located at different elevations.
48. 48. A process, characterized in that it comprises: (a) introducing a reaction medium into an upper section of a reactor comprising a plurality of trays unidirectional inclines and a plurality of bidirectional inclined trays; (b) causing the reaction medium to flow down into the reactor on unidirectional and bidirectional trays; and (c) withdrawing the reaction medium from a lower section of the reactor.
49. 49. The process according to claim 48, characterized in that the average thickness of the reaction medium flowing over the vertically spaced trays is at least about 2.5 inches.
50. 50. The process according to claim 48, characterized in that the dynamic viscosity of the reaction medium removed from the reactor is at least 50 percent greater than the dynamic viscosity of the reaction medium introduced into the reactor.
51. 51. The process according to claim 48, characterized in that the inclination of the unidirectional trays increases downwards.
52. 52. The process according to claim 51, characterized in that the inclination of the bidirectional trays increases downwards.
53. 53. The process according to claim 48, characterized in that at least a portion of the unidirectional trays are located above at least a portion of the bidirectional trays.
54. 54. The process according to claim 53, characterized in that the process includes separating the reaction medium flowing downwards in two substantially equal portions prior to causing the reaction medium to flow on the bidirectional trays.
55. 55. The process in accordance with the indication 48, characterized in that the adjacent ones of the unidirectional chats are inclined in opposite directions, wherein the bidirectional trays include alternating roof and duct trays, wherein the roof trays include a pair of downwardly diverging roof members, wherein the trays of conduit include a pair of converging downward duct members.
56. 56. The process according to the rei indication 48, characterized in that the plurality of unidirectional trays includes a top group of unidirectional trays and a lower group of unidirectional trays, wherein the reaction medium flows back and forth over the upper group of trays. the unidirectional trays in a first direction, wherein the reaction medium flows back and forth over the lower group of the unidirectional trays in a second direction, wherein the first and second directions are substantially perpendicular to each other.
57. 57. The process in accordance with the claim 48, characterized in that at least 10 percent of all the trays in the reactor are unidirectional trays and at least 10 percent of all trays in the reactor are bidirectional trays.
58. 58. The process according to claim 48, characterized in that at least a portion of the unidirectional trays include an upwardly extending weir on which at least a portion of the reaction medium flows in order to pass to the next tray located immediately below it.
59. 59. The process according to claim 58, characterized in that the landfill has a height of at least 2.5 inches.
60. 60. The process according to claim 48, characterized in that the degree of polymerization (DP) of the reaction medium introduced into the reactor is in the range of about 20 to about 75, wherein the DP of the reaction medium withdrawn from the The reactor is at least 50 percent larger than the DP of the reaction medium introduced into the reactor.
61. 61. The process according to claim 60, characterized in that the reaction medium withdrawn from the reactor comprises polyethylene terephthalate (PET).
62. 62. The conformance polymerization process with claim 48, characterized in that the reaction medium is maintained at a temperature in the range of about 250 to about 325 ° C and at a pressure in the range of about 0.1 to about 4 torr in the reaction.
63. 63. The process according to claim 44, characterized in that it further comprises causing at least a portion of the reaction medium to flow simultaneously over two generally opposite ends of at least one of the unidirectional trays.
64. 64. The process according to claim 63, characterized in that the generally opposite ends of the unidirectional trays are located at different elevations.