Low cost polyester process using a pipe reactor

A RECOVERY PROCESS OF A DIHIDROXI COMPOUND OF A

POLYESTER REACTION FLUID FLOW Field of the Invention

This invention relates generally to polyester apparatus and processes, more specifically, to polyester apparatus and processes comprising an absorption system in the absence of a water column and other components of the distillation system.

Background of the Invention

Because the polyester manufacturing business becomes increasingly competitive, alternative manufacturing processes and devices of lower cost have become highly desirable. A variety of processes and devices have been developed, however, these systems contain complex and expensive designs that cannot be built or installed quickly. They also require great experience to maintain and operate them properly. For example, in typical polyester processing facilities, it is common for a reactor system to contain a series of distillation columns to, among other purposes, coat unreacted dihydroxy compounds that may be contained in the flow rates of various fluids. that result from polyester manufacturing processes.

A typical distillation system will comprise a water column, a separation column, an MGM column (monomer column and mixed glycol or condensed column of ethylene glycol). Commonly, the flow rates of fluids that arise from one or more reactors are sent to the water column.

There, water is separated from glycol or another dihydroxy compound. The products that

207698 they have a low boiling point, taies like water, they are removed from the part

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top of the column and sent to the separation column, and the compounds

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Dihydroxy taies such as glycol and other products that boil at high temperature are removed from the bottom of the column, where they can be sent back to the reactor system or, alternatively, sent to the storage facility. The separation column separates several components at the top of the separation column, such as paradioxane, which cannot be sent to a wastewater treatment plant.

These are complex and expensive operations of the unit, which require significant amounts of space for proper installation and operation. Therefore, there is a need in the art to obtain a lower cost, simpler devices and processes to separate and recover dihydroxy compounds that did not react from the flow rates that may result from a polyester manufacturing process.

Brief Description of the Invention

Among other aspects, the present invention provides a process and an apparatus for the separation and recovery of a dihydroxy compound from the flow rates resulting from a polyester manufacturing process. More specifically, the invention provides the use of an absorption system in the absence of a water column and other distillation devices to provide a more compact and effective means for the recovery of a dihydroxy compound. Thus, the use of an absorption system according to the present invention in a polyester manufacturing process can reduce and even eliminate the need for columns, equipment, tanks, agitators, difficult handling pumps and the like.

Therefore, in a first aspect, the present invention provides a process for the recovery of a dihydroxy compound from a fluid flow resulting from the preparation of a polyester comprising: (a) the supply of a reactor having an internal volume in which at least a portion of the internal volume is occupied by a reaction mixture comprising at least one dicarboxylic acid or its ester and at least one dihydroxy compound; (b) the esterification and transesterification of at least one dicarboxylic acid or its ester with at least one dihydroxy compound in the reactor to produce therethrough: (i) an esterification product or a transesterification product: and (ii) a fluid flow rate comprising at least one dihydroxy compound; and (c) subjecting the fluid flow resulting from the esterification and transesterification reaction of step (b) to an absorption system to selectively recover the dihydroxy compound.

In a second aspect, the present invention provides a process for the recovery of a dihydroxy compound from a fluid flow resulting from the preparation of a polyester polymer comprising the steps of: (a) providing a reactor having an internal volume in which at least a portion of the internal volume is occupied by a polyester monomer: (b) the polycondensation of the polyester monomer to produce a polyester polymer and a fluid flow rate comprising the dihydroxy compound: and (c) subjecting the fluid flow rate resulting from the polycondensation reaction to an absorption system to recover in Selectively form the dihydroxy compound.

In a third aspect, the present invention provides a process for the recovery of a dihydroxy compound from a fluid flow resulting from the preparation of a polyester polymer comprising the steps of: (a) providing a first reactor having a first internal volume in which at least a portion of the first internal volume is occupied by a reaction mixture comprising at least one component of dicarboxylic acid and at least one component of the dihydroxy compound; (b) the esterification and transestirification of at least one component of dicarboxylic acid with at

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less a component of dihydroxy compound to produce: (i) urt ìfèadóct

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esterification or a transesterification product; and (ii) a first fluid flow rate comprising the dihydroxy compound; (c) providing a second reactor in fluid communication with the first reactor having a second internal volume in which at least a portion of the second internal volume is occupied by the product of the esterification or transesterification of step (b); (d) the polycondensation of the esterification or transesterification product of step (c) to produce a polyester polymer and a second fluid flow rate comprising a dihydroxy compound; and (e) subjecting the first fluid flow of step (b) and the second fluid flow of step (d) to an absorption system to selectively recover the dihydroxy compound.

In another aspect, the present invention further provides a process for the recovery of the dihydroxy compound from the fluid flow resulting from the preparation of a polyester comprising the steps of: (a) providing a reactor having an internal volume in the which at least a portion of the internal volume is occupied by a reaction mixture comprising at least one dicarboxylic acid or its ester and at least one dihydroxy compound; (b) the esterification or transesterification of at least one dicarboxylic acid or its ester with at least one dihydroxy compound in the reactor to produce therein: (i) an esterification or transesterification product; and (ii) a fluid flow rate comprising at least one dihydroxy compound; and (c) in the absence of a water column, subjecting the flow of fluid resulting from the esterification or transesterification reaction of step (b) to an absorption system until the dihydroxy compound is selectively recovered.

Additional advantages and embodiments of the invention will be obvious from the description, or can be learned through the practice of the invention. Further advantages of the

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invention by means of the elements and combinations defined Particular in the appended claims. Therefore, it should be understood that the foregoing general description and the detailed description of the following are exemplary and explanatory of certain embodiments of the invention and are not restricted to the invention as claimed.

Brief Description of the Figures

For a clearer understanding of the present invention, reference is now made, by way of example only, to the attached Figure 1, which shows a particular apparatus and configuration for use in practice of an embodiment of the present invention.

Detailed description of the invention

The present invention can be understood more quickly by reference to the following detailed description and any example provided herein. In addition, it should be understood that this invention is not limited to the specified embodiments and methods described below, since specific components and / or conditions may vary, of course. In addition, the terminology used here is only for the purpose of describing particular embodiments of the present invention and is not intended, in any way, to have limiting character.

It should also be noted that, as is used in the specification and in the appended claims, the singular form "a", "a", and "the" comprises plural referents unless the context indicates otherwise in clear way. For example, in reference to a single component, it is intended to comprise a plurality of components.

The ranges can be expressed here as from "about" a particular value and / or "about" another particular value. When such range is expressed, another embodiment comprises from a particular value and / or to another

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r

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INDUSTRIALI f Refoliated Ν 'particular value. Similarly, when values ​​are expressed as approximations, through the use of the preceding word "approximately", it will be understood that the particular value forms another embodiment.

In the course of this application, where it is made^- With reference to the publications, the totality of the discoveries of these publications are hereby incorporated by reference in this application in their entirety to more fully describe the state of the art to which this invention belongs.

As used in the specification and in the final claims, the residues refer to the portion that is the product resulting from the chemical species in a particular reaction scheme or the subsequent formulation or the chemical, regardless of whether the functional group it is obtained, in effect, from chemical species. Thus, for example, an ethylene glycol residue in a polyester refers to one or more OCH repeating units.₂CH₂O- in the polyester, regardless of whether ethylene glycol is used to prepare the polyester. Similarly, the residue of sebacic acid in a polyester refers to one or more functional groups of CO (CH₂)₈CO- in the polyester, regardless of whether the residue is obtained by reacting the sebacid acid or an ester from there until the polyester is obtained.

In a first embodiment, the present invention provides a process for the recovery of a dihydroxy compound from the fluid flow resulting from the preparation of a polyester comprising the steps of: a) providing a first reactor having a first internal volume in which at least a portion of the first internal volume is occupied by a reaction mixture comprising at least one dicarboxylic acid component or its ester and at least one dihydroxy component; (b) the esterification and transesterification of at least r

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a dicarboxylic acid component with at least one dihydroxy compound component in the reactor to produce: (i) an esterification product or a transesterification product; and (ii) a fluid flow rate comprising the dihydroxy compound; and (c) subjecting the flow of fluid resulting from the esterification or transesterification reaction of step (b) to an absorption system to selectively recover the dihydroxy compound.

In a second embodiment, the present invention provides a process for the recovery of a dihydroxy compound from a fluid flow resulting from the preparation of a polyester polymer comprising the steps of: (a) providing a reactor having a internal volume in which at least a portion of the internal volume is occupied by a polyester monomer; (b) the polycondensation of the polyester monomer to produce a flow rate polyester polymer comprising a dihydroxy compound; and (c) subjecting the fluid flow rate resulting from the polycondensation reaction to an absorption system to selectively recover the dihydroxy compound.

In a third embodiment, the present invention provides a process for the recovery of a dihydroxy compound from a fluid flow resulting from the preparation of a polyester polymer comprising the steps of: (a) providing a first reactor having a first internal volume in which at least a portion of the first internal volume is occupied by a reaction mixture comprising at least one dicarboxylic acid component and at least one dihydroxy compound component; (b) the esterification and transesterification of at least one component of dicarboxylic acid with at least one component of dihydroxy compound to produce: (i) an esterification product or a transesterification product; and (ii) a first fluid flow rate comprising the dihydroxy compound; (c) provide a

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L 8 second reactor in fluid communication second internal volume in which at least a portion of the second internal volume is occupied by the product of the esterification or transesterification of step (b); (d) the polycondensation of the esterification or transesterification product of step (c) to produce a polyester polymer and a second fluid flow rate comprising a dihydroxy compound; and (e) subjecting the first fluid flow of step (b) and the second fluid flow of step (d) to an absorption system to selectively recover the dihydroxy compound.

In addition, it should be understood that the process and apparatus of the present invention can be used in conjunction with any known polyester formation process. Therefore, as used in the specification and in the appended claims, the phrase "polyester process" refers to an esterification process, an ester exchange process or even a polycondensation process. Alternatively, the polyester process of the present invention can be any known process for the formation of a polyester monomer, a polyester oligomer and / or a homopolymer and / or a polyester copolymer.

To this end, it should be understood that, as used herein, it is intended that the term "polyester" includes any derivative of polyester, which includes, without limitation, polyesters, polyester amides and polyether ester amides. Therefore, for the sake of simplicity, throughout the specification and the claims, the terms polyester, polyether ester, polyester amide and polyether etheramide can be used interchangeably and typically refer to polyesters, but It should be understood that the particular polyester species depends on the initial materials, that is, reagents and / or polyester precursor components.

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esterification "refers to a polyester process in which the reagent with an acid functionality, such as a dicarboxylic acid, reacts to produce a polyester product. Also, as such is used herein, the term "ester exchange process" or "ester exchange reaction" refers to a polyester process in which a reagent with an alkyl terminal group, such as a methyl end group reacts to produce a polyester product. Therefore, for simplicity, throughout the specification and the appended claims, the terms esterification and ester exchange are used interchangeably and typically refer to an esterification, but it should be understood that the esterification or The ester exchange depends on the initial materials.

Furthermore, it is the objective of the present invention that an esterification or ester exchange process comprises one or more features of the integrated process. For example, in one embodiment, an esterification process may comprise an esterification reactor. However, in an alternative embodiment, it is possible that the esterification process comprises a system or train of esterification reactors that are configured in series, in parallel, or their combination. Therefore, in another embodiment, the esterification process may comprise two or more esterification reactors, all of which are preferably in fluid communication with each other.

As used herein, the term "polycondensation" is intended to refer to any known process for the formation of an oligomer and / or a polymer. For example, in one embodiment, a polycondensation process according to the present invention is a process for the formation of a polyester oligomer and / or a polyester polymer.

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In addition, in a manner similar to an esterification process &lt;come 'ⁱdefined above, the polycondensation process can also comprise one or more characteristics of a separate or integrated process. For example, in one embodiment, the polycondensation process may comprise a polycondensation reactor. However, in an alternative embodiment, the polycondensation process may comprise a system or a train of two or more polycondensation reactors that are configured in series, in paralysis or their combination. Therefore, in a second embodiment, the polycondensation process of the present invention may comprise two or more polycondensation reactors, all of which are preferably in fluid communication with each other. In another embodiment, the polycondensation process comprises a first prepolymer or oligomer polycondensation reactor in fluid communication with a terminator or polymer reactor.

For that purpose, as such is used herein, it is intended that the term "prepolymer reactor" or "oligomer reactor" refers to a first polycondensation reactor. Although not required, the prepolymer reactor is typically maintained in vacuo. A person of ordinary skill in the art will appreciate that a polymer reactor is frequently used, without limitation, to initially develop a prepolymer chain from a feed length of approximately 1 to 5, to an output length of approximately 4 to 30.

In connection with this, it is intended that the term "termination reactor" or "polymer reactor" such as used herein, refer to the last melting phase of the polycondensation reaction system. Again, although not required, the second termination or polycondensation reactors are kept under vacuum. In addition, a person with common skill in art

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It will be appreciated that the termination reactor is frequently used * to develop the polymer chain to the desired final length.

The term reactor, such as horn is used in the specification and in the appended claims, is intended to refer to any reactor that is suitable for use in a polyester process such as horn described above. Thus, a suitable reactor for use with the process and the apparatus of the present invention is a reactor that is configured to define an internal volume in which during any polyester process, at least a portion of the internal volume of the reactor is occupied by a reaction mixture.

Examples of a reactor suitable for use with the process of the present invention include, without limitation, a pipe reactor, such as that published in Provisionai Application of the United States with Series Number 60 / 254.040, filed 7 December 2000, and the US Utility Patent Application for a "Low Cost Polyester Process Using a Pipe Reactor", filed on December 7, 2001, whose applications are incorporated here in their entirety by means of this reference for all purposes. In an alternative embodiment, the present invention can be implemented with a continuously stirred tank reactor, a reactive distillation column, a stirred pipe reactor, a siphon thermal reactor, a forced recirculation reactor, a reactor drip bed, and any other reactor or reactor mechanism known for use in a chemical manufacturing process. In addition, it should be understood that it is within the scope of the present invention that any of the reactors set forth herein are configured for use both in a continuous polyester, batch or semi-batch manufacturing process.

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As used herein, it is intended that the term or phrase "fluid" or "fluid flow rate" refers to any liquid, vapor or gas, or mixtures thereof that is present within or resurfaces from any region of a reactor system of polyester manufacturing process. For example, without limitation, a fluid flow rate according to the present invention may come from a CSTR reactor and / or a pipe reactor. Also, the fluid flow rate can come from an esterification or an ester exchange reactor, a polycondensation reactor or a combination thereof. To this end, the fluid or fluid flow can be any excess fluid flow that does not contain a significant amount of a polyester reaction product.

Suitable dicarboxylic acids for use in the present invention include aromatic dicarboxylic acids having, preferably, 8 to 14 carbon atoms, cycloaliphatic dicarboxylic acids having 4 to 12 carbon atoms. Specific examples of dicarboxylic acids include terephthalic acid, phthalic acid, isophthalic acid, naphthalen-2,6-dicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexanediacetic acid, diphenyl-4,4'-dicarboxylic acid, diphenyl-3,4'-dicarboxylic acid succinic, glutaric acid, adipic acid, azelaic acid, sebacic acid, and mixtures thereof, and the like.

Likewise, suitable dihydroxy compounds according to the present invention include cycloaliphatic diols preferably having 6 to 20 carbon atoms or aliphatic diols preferably having 3 to 20 carbon atoms. Specific examples of taies diols include ethylene glycol, diethylene glycol, triethylene glycol, 1,4-cyclohexane-dimetanol-propane-1,3-diol, butan-1,4diol, pentan-1,5-diol, hexane-1,6-diol, Neopentyl glycol, 3-methylpentanediol- (2,4), 2-methylpentanediol- (1,4), 2,2,4-trimethylpentane-diol- (1,3), 2-ethylhexandiol- (1,3), 2,2-methylpropan- diol- (1,3), hexandiol- (1,3), 1,4-di- (hydroxyethoxy) -benzene, 2,2-bis- (4-hydroxycycloexyl) -propane, 2,4-dihydroxy-1,1, 3,3-tetramethyl-cyclobutane, 2,2,4,4

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tetramethylcyclobutanediol, 2,2-bis- (3-hydroxyethoxyphenyl) -propane, 2,2-bis- (4-hydroxypropoxyphenyl) -propane, isosorbide, hydroquinone, and mixtures thereof and the like.

Co-monomers of suitable dicarboxylic acids include, without limitation, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, esters of aliphatic or aromatic dicarboxylic acids, anhydrides of aliphatic or aromatic dicarboxylic esters, and mixtures thereof. In one embodiment, it is preferred that suitable dihydroxy co-monomers include cycloaliphatic diols that preferably possess 6 to 20 carbon atoms or aliphatic diols preferably possess 3 to 20 carbon atoms. More specific examples of taies diol co-monomers include ethylene glycol, diethylene glycol, triethylene glycol, 1,4-cyclohexane-dimetanol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol hexane- 1,6, neopentyl glycol, 3-methylpentanediol- (2,4), 2-methylpentanediol- (1,4), 2,2,4-trimethylpentane-diol- (1,3), 2-ethylhexanediol- (1,3), 2,2-methylpropane-diol- (1,3), hexanediol- (1,3), 1,4-di- (hydroxyethoxy) -benzene, 2,2-bis (4-hydroxycycloexyl) -propane, 2,4-dihydroxy -1,1,3,3-tetramethyl-cyclobutane, 2,2,4,4 tetramethylcyclobutanediol, 2,2-bis- (3-hydroxyethoxyphenyl) -propane, 2,2-bis- (4-hydroxypropoxyphenyl) -propane, isosorbide, hydroquinone, BDS- (2,2- (sulfonylbis) 4 , 1phenyloxy)) bis (ethanol), mixtures thereof and the like.

As used herein, an "absorption system" refers to one or more absorption beds, which are configured in series, in parallel or combinations thereof, which are designed to effect reagent transfer from the unreacted polyester process or the excess, that is, a dihydroxy compound, or a byproduct of the polyester process, from a fluid phase to one or more surfaces of the absorption bed to be desorbed and coated at a later time. To this end, absorption beds suitable for use in the process of the present invention are well known in the art and are available from a number of companies in the

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According to the present invention, preferably, it uses three or more absorption beds to selectively absorb and desorb a dihydroxy component / s of a fluid flow rate through a combination of absorption, desorption, and eidos, phases or sequencing. standby (standby).

While applicable to any chemical process, the present invention is particularly useful for the recovery of components from a polyester manufacturing process. To this end, the preferred polyester manufacturing processes according to the present invention include, without limitation, processes for the manufacture of PET homo- and co-polymers, PETG (PET modified with the CHDM co-monomer), polyesters aromatics in their entirety or of liquid crystal polyethers, biodegradable polyesters comprising butandiol, terephthalic acid and adipic acid, homopolymers and copolymers of poly (cyclohexan-dimethylene terephthalate), homopolymers and copolymers of CHDM, and dimethyl cyclohexandicarboxylate, aliphatic-aromatic copolyesters, and mixtures thereof.

The use of the absorption system for the recovery of reagents that did not react and / or in excess, or for the recovery of secondary products from a polyester manufacturing process can advantageously reduce or eliminate columns, equipment, tanks, agitators , pumps, etc., and in one aspect of the present invention, you can replace them with few simple tanks or large pipes, a compressor, and two heat exchange devices. Several advantages will be apparent to a person skilled in the art in practicing the present invention.

For example, an absorption system can conserve energy in the sense that the reflux passage present within a conventional distillation column is not required. In addition, it will be appreciated that an absorption system¹ and «Wimm? FêACîôMAL

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It provides advantages for the recovery of purer products and fewer secondary products when compared to a distillation system. For example, in one embodiment in which a flow rate of fluid comprises ethylene glycol of liquid and / or steam, the absorption system will provide advantages for the recovery of purer products and much less, if any, secondary products such as water. This can be a significant advantage because, as discussed here, the dihydroxy compound coated such as ethylene glycol can be recirculated to any desired location within the reactor system, such as the esterification or ester exchange reactor. In addition, the presence of water in the esterification or ester exchange reactor can significantly reduce the reaction rate within it. Thus, through the recovery of a dihydroxy compound with a lower water content and through the use of the same reactor system, a higher reaction rate can be obtained, thereby allowing a smaller reactor system. esterification or ester exchanges.

With specific reference to Figure 1, which illustrates an embodiment of the invention, an apparatus is shown for use in the practice of a particular embodiment of the invention. According to this embodiment, an absorption system is provided comprising a first, second and third absorption bed, in which the first, second and third absorption bed are in selectively controlled fluid communication with a fluid flow rate that It results from a polyester manufacturing process.

In one embodiment, the first, second and third absorption beds described above are subjected to at least one continuous cycle comprising: (a) (i) a first phase comprising the passage of a fluid flow rate through a completely desorbed absorption bed until the first absorption bed is substantially saturated with at least one

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total desorption of at least one component of a second saturated absorption bed completely through the passage of a flow of inert gas through the second saturated absorption bed completely; and (iii) simultaneously with steps to (i) and (ii), the maintenance of a third desorbed bed completely desorbed in standby mode (standby); (b) (i) a second phase comprising the passage of a fluid flow through a third bed completely desorbed until the third absorption bed is substantially saturated with at least one component of a first bed of full saturated absorption by means of the passage of a flow of inert gas through the first fully saturated absorption bed; and (iii) simultaneously with steps b (i) and b (ii), the maintenance of a second absorption bed completely desorbed in standby mode (standby); and (c) (i) a third phase comprising the passage of a fluid flow through a second absorption bed completely desorbed until the second absorption bed is substantially saturated with at least one component of the flow of fluid; (ii) simultaneously with step c (i) the complete desorption of at least one component of a third saturated absorption bed completely through the passage of an inert gas flow through the third absorption bed fully saturated; and (iii) simultaneously with steps c (i) and c (ii), the maintenance of the first desorbed bed completely desorbed in standby mode.

It should also be understood that the term "standby mode (standby)" as used herein, in one embodiment, refers to a mode of operation in which an absorption bed is maintained as an absorbed bed completely desorbed by means of which a fluid flow rate

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alternatively, in another embodiment, an absorption bed that is not operating in standby mode (on hold) can simultaneously be saturated or partially charged with a minimum amount of dihydroxy gas / vapor and / or liquid contained within of a fluid flow that exists in the condenser. Therefore, it is also within the scope of the present invention that a completely desorbed absorption bed operating in the standby mode (standby) also simultaneously purifies a flow of fluid that exists in the condenser.

Returning to Figure 1, as shown in the drawing, a fluid flow rate from one or more reactors is fed to the first absorption bed 181 as flow rate 189 and exists at flow rate 190. To this end, the vapors and gases present within the fluid flow normally originate from an esterification reactor or an ester exchange reactor. However, it is also contemplated that such vapors come from a ventilation mechanism designed to remove incoming vapors that are present within the circulating fluids that are circulating through a recirculation circuit such as that published in the Provisionai Request for the United States with Series Number 60 / 254.040, filed on December 7, 2000, whose application is incorporated herein in its entirety as reference. In one embodiment, the vapors and gases within the fluid flow rate comprise ethylene glycol.

Liquids that are present within the fluid flow will originate, typically, from polycondensation reactors and other flows that may result from pump purge devices, pump seals, suction pumps, purge devices evaporators, intercondensers, and the like, and mixtures thereof. Therefore, in another embodiment,

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liquid.

In a preferred embodiment, the flow 190 has a continuous monitoring instrument that indicates when a component to be maintained is in existence in the bed. Any known instrument and / or medium can be used for continuous flow monitoring, such as the FTIR device, however, it would be appropriate to monitor a single wave with sufficient experience in which a redirection of flow 190 could be performed with a chronometer after having gained the necessary experience. In addition, monitoring could be accompanied by the realization of samples of manual hooks.

Until and unless there is a desired component, the absorber such as the monitoring device indicates, all other components are sent through the flow 190 to the flow 184. The flow 184 goes to a thermal destruction device such as the medium homo Heat Transfer, a fermai oxidizer, a catalytic oxidizer, or the like. Once the bed 181 is saturated and the desired component begins to flow out of the flow 190, the fluid flow comprising the desired component is then returned to the next absorption bed.

For the sake of simplicity, in order to use the same drawing, the bed 181 is now shown as a partially loaded bed that is being saturated by means of the flow 189 from one or more reactors. Absorption bed 182 is the current fully saturated bed that was described in the preceding paragraph. Absorption bed 183 is a bed that was completely desorbed. Bed 181 is now saturating as previously described.

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The bed 182 has a hot flow of inert gas, such as nitrogen, carbon dioxide, argon, and the like supplied to it by means of the flow 191 and which come from the heat exchange device 188 which is heating the inert gas flow. It should be understood that any convenient source of heat can be used such as steam, electricity, steam or hot gas, or hot liquids such as heat transfer media and the like. In an alternative embodiment, the heat can also be exchanged between the condenser flows 187, 189, 192, 193 and the flow rate 191. In addition, it is also contemplated by the present invention that conventional air can be used up to heat air exchange devices in addition to solid bed exchange devices.

The driving force for the inert gas flow comes from a compressor or compressor 186 although an eductor design with the inert composition flow 197 can be used. The pressure at the inlet of the component 186 is maintained by adding the gas flow inert 197 and recirculation flow 195.

The inert hot gas entering the bed 182 desorbs the bed components. Alternatively, steam or other condensable hot steam may be used, but this could decrease the purity of the existing flow rate and also requires additional separation equipment for the flow rate. Those with experience in the art appreciate that the flow and temperature of the flow 191 can be controlled to precisely desorbed the bed 182 until the desorbed components are separated into highly pure and discrete pulses. These pulses that exist in the flow 192 and can be monitored by means of a device similar to that used in the flow 190. When an unwanted component of bed 182 is removed at flow rate 192, a 3-way valve or 2-way multi-valve valves are activated and flow rate 192 is redirected by / Ί

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mean of the flow 198 to the thermal oxidation device per m? flow rate 184. Alternatively, flow rate 192 could pass through an uncooled condenser 185 and go to flow rate 184 for thermal oxidation.

When a desired component is removed from bed 182 at flow rate 192, the valves are activated and flow rate 192 goes to flow rate 199 and condenser 185. Condenser 185 can be cooled with air, chilled water, refrigerated gas, an expansive cooling process, or any other appropriate means of cooling that is known by that person with common skill in the art. The cooled flow 199 will fall below the saturation temperature and more, if not all of the desired component that was present as a vapor or gas will condense from the flow rate as a liquid. The liquid in the flow 187 is then directed to the appropriate storage container for that product. However, in an alternative embodiment, the dihydroxy condensate component can be directly recycled back to a reactor for subsequent inclusion in the preparation of a polyester monomer, oligomer or polymer.

Once the flow 192 contains again an unwanted component, a device is reconfigured to selectively direct the flow, such as a valve, switch or other means of control or redirection, such that the flow 192 goes to the thermal oxidation device. This selective direction, or the process of maneuvering between the desired and unwanted components continues until the bed 182 is completely desorbed at which point the bed 182 is placed in standby.

An output condenser of the fluid flow 185 the flow 193 may also contain a minimum amount of the component to be recovered, but is generally below the saturation temperature of the condenser 185. Thus, in one embodiment, the flow 193 then t

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sends to bed that was completely desorbed 183. Bed 183 aWôfbé^xThe desired components whereby purifies the flow 193. The flow 193 then leaves the bed 183 as flow 195. The flow 197 then adds inert filling gas to maintain a constant inlet pressure to the compressor 186.

Once the bed 181 becomes saturated and the bed 182 is desorbed, the cycle of the bed functions. Therefore, bed 181 takes the place of bed 182 in the cycle; bed 182 takes the place of bed 183; and bed 183 takes the place of bed 181. Therefore, in a second phase, the bed 181 will be desorbed; bed 182 will be in standby (and on hold) and / or the desired absorption components of condenser 185; and bed 183 will be saturated with at least one component of the steam flow. Once the bed 181 is desorbed and the bed 183 becomes saturated, the functions of the bed will cycle at a third time and the three phase will begin.

It should be understood that further increases based on the sizes and products of the system being produced may be necessary. For example, multiple absorber beds may be required for each function as well as multiple cooling devices, compressors, heaters, and heat exchange devices.

Throughout this application, reference is made to several publications. The findings of these publications are incorporated herein in their entirety as reference in this application in order to more fully describe the state of the art to which this invention belongs.

Although the present invention has been described with reference to specific details of certain embodiments from there, it is not intended that such details be taken as limiting within the scope of the invention except and to the extent to which they are included in the accompanying claims. .

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While this invention has been described in connection with preferred embodiments, it is not intended to limit the scope to the particular embodiments that are established, but, on the contrary, it is intended to cover such asitemative, modification, and equivalent equivalents as may be included. within the spirit and scope of the invention such as the appended claims is defined. For example, there are numerous variations and combinations of reaction conditions, for example, component concentrations, desired solvents, solvent mixtures, temperatures, and value arrangements, which can be used to optimize the purity of the product and performance obtained from the process described. In addition, a person with experience in the art will appreciate that in the practice of this process, only reasonable and routine experimentation will be needed to optimize such process conditions.