CN103443064A - Method for treating purified terephthalic acid mother liquor - Google Patents
Method for treating purified terephthalic acid mother liquor Download PDFInfo
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- CN103443064A CN103443064A CN2011800679515A CN201180067951A CN103443064A CN 103443064 A CN103443064 A CN 103443064A CN 2011800679515 A CN2011800679515 A CN 2011800679515A CN 201180067951 A CN201180067951 A CN 201180067951A CN 103443064 A CN103443064 A CN 103443064A
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- C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
- C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
- C07C51/255—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting
- C07C51/265—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting having alkyl side chains which are oxidised to carboxyl groups
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Abstract
In the present invention, a purified terephthalic slurry generated in the process of producing high-purity terephthalic acid by liquid-phase oxidation and hydrogenation purification using p-xylene as a starting material is separated into a primary mother liquor and primary crystals of the purified terephthalic acid. Terephthalic acid as well as p-toluic acid and other dissolved matter are cooled and precipitated in the separated primary mother liquor, and separated by filtration to separate out and recover low-purity terephthalic acid crystals, as a part of a raw material for the liquid-phase oxidation reaction of p-xylene. Terephthalic acid crystals are newly added to and mixed in the separated primary mother liquor, and thereafter the mixture is fed to a cooling tank adjusted to have a reduced pressure less than atmospheric pressure, and cooled by pressure relief, thereby improving the filterability of the precipitated matter. The amount of residual dissolved matter in a secondary mother liquor also separated by filtration is reduced.
Description
Technical field
The present invention relates to the treatment process of purified terephthalic mother liquor,, in the technique of manufacturing highly purified purified terephthalic (PTA), the treatment process that the mother liquor that the solid-liquid separation from the purified terephthalic slurry is obtained (mother liquor) is processed effectively; This technique, that the dissolving crystallized of the crude terephthalic acid that will manufacture by the liquid-phase oxidation of p-Xylol is in the water of high temperature, high pressure, carry out after hydrofinishing carrying out cooling, generate the purified terephthalic slurry, then, carry out drying through solid-liquid separation and washing procedure, manufacture highly purified purified terephthalic (PTA).
Background technology
Take p-Xylol as raw material, in acetate solvate and under the existence of oxide catalyst, utilize oxygen-containing gas to carry out liquid-phase oxidation, manufacture crude terephthalic acid (CTA), afterwards, crude terephthalic acid is dissolved in the water solvent of high temperature, high pressure, under the existence of reducing catalyst, utilize hydrogen-containing gas to carry out hydrofinishing, obtain Purified Water solution, the cooling Crystallization Procedure that bleeds off pressure through pressure stage property ground is reduced, generate the purified terephthalic slurry again.Then, carry out the solid-liquid separation of this purified terephthalic slurry and reclaim crystallization, as fiber with, film the high purity terephthalic acid by the polyester manufacturing direction of, bottle use, manufacture purified terephthalic (PTA) crystalline powder that has passed through drying process.
In such manufacturing process, when generating highly purified terephthaldehyde's acid crystal (primary crystallization), the contained impurity such as 4-carboxyl benzaldehyde (4-CBA) of crude terephthalic acid are reduced into para Toluic Acid etc. by hydrogenation, bleed off pressure cooling after, generate the dissolved separation mother liquor of most para Toluic Acid (mother liquor).In addition, simultaneously, in separation temperature to become during saturated terephthalic acid also is dissolved in this mother liquor.
Therefore, proposed further to carry out cooling by this mother liquor, make to dissolve terephthalic acid and dissolved impurity is separated out, reclaim the low terephthaldehyde's acid crystal (secondary crystal) of purity, the oxidizing reaction of itself and p-Xylol is coexisted etc. and effectively utilize method (No. 56-35175, examined patent publication, No. 5-58948, Unexamined Patent).
On the other hand, also propose directly carry out or the processing such as distill respectively having isolated mother liquor (secondary mother liquid) after this low-purity terephthaldehyde acid crystal (secondary crystal), make water solvent for dissolving the crude terephthalic acid crystallization and reused etc. and effectively to use the method for secondary mother liquid.
But, the para Toluic Acid of containing a large amount of impurity that becomes purified terephthalic (PTA) crystallization in secondary mother liquid due to this motion, therefore, being only limited to a part directly uses as the water solvent that dissolves crude terephthalic acid (CTA) crystallization, after distilling respectively and process with 25～125 sections of reflux ratio 2～10 and number of theoretical platess, the washing water of the dissolved water using recycle-water as crude terephthalic acid or purified terephthalic (PTA) crystallization (primary crystallization) are used (No. 5-58948, Unexamined Patent).
The sensing of the reduction of the expansion needed along with polyester and economizing on resources in recent years, carrying capacity of environment, these motions are being applied to manufacture in high purity terephthalic acid's commercial apparatus.Therefore, the demand that a large amount of mother liquors is applied flexibly uprises, and thus, for the problem of practical application, also highlights.
As one of its problem, mother liquor is being carried out when cooling, although be cooled to final separation temperature quickly, now, due to the particle diameter of secondary crystal attenuates, the secondary crystal retrieving arrangement forms high loading and fine crystalline to the adhering to of refrigerating unit etc., obstruction etc., practicality in, existence bothers.Therefore, following improvement method has been proposed: mother liquor being bled off pressure when cooling, adopt a plurality of cooling tanks that periodically reduce pressure to make secondary crystal separate out (No. 2006-8671, JP).
In addition, because the usage quantity of secondary mother liquid enlarges, therefore proposed to make secondary mother liquid further to contact with the synthetic sorbing material such as SEPABEADS (Mitsubishi Chemical's system) and eliminated para Toluic Acid's method.(No. 2006-8671, JP)
In above situation, the inventor etc. have proposed the treatment process of a mother liquor: under the existence of terephthaldehyde's acid crystal, a mother liquor is carried out to flash distillation (bleeding off pressure) and/or heating evaporation, make vaporized solvent vapour condense, reclaim, obtain the recycle-water that foreign matter content further reduces, thus, increase the amount of re-using.The treatment process of this mother liquor, not to use the distillation tower of 2～10 reflux ratio, 25～125 number of theoretical plates to distill respectively, but the condensation water that can produce by obtaining evaporation operation reclaims the further method (WO2009/141968) of the water medium of reduction of para Toluic Acid.
The prior art document
Patent documentation
Patent documentation 1: examined patent publication 56-35175 communique
Patent documentation 2: Unexamined Patent 05-58948 communique
Patent documentation 3: JP 2006-8671 communique
Patent documentation 4: No. 2009/141968th, International Publication
Summary of the invention
The problem that invention will solve
As mentioned above, when the method that separated mother liquor from terephthalic acid refinement (mother liquor) is separated into respectively to secondary crystal and secondary mother liquid and carries out effectively utilizing is applied to utility unit, the suspension that mother liquor generates by method of cooling is because suspended particles (secondary crystal) are fine and have adhesivity, therefore, there is difficult point in processing, in the separation of these suspended particles (secondary crystal), can cause the obstruction of strainer or the decline of the rate of recovery.
On the other hand, secondary mother liquid is because dissolved impurity is residual, when the dissolved water of using as hydrofinishing recycles, need the processing such as evaporation or distillation, to this, when direct circulation is used not carrying out any processing, there is the restricted problem of its purposes and usage quantity thereof.
The object of the invention is to: when manufacturing purified terephthalic, with simple treatment process and good strainability Separation and Recovery low-purity terephthaldehyde acid crystal (secondary crystal) from isolated mother liquor together with primary crystallization (mother liquor).
In addition, the object of the invention is to: recycle the low-purity terephthaldehyde's acid crystal (secondary crystal) with good strainability Separation and Recovery in the part by the manufacture raw material at terephthalic acid, improve yield of terephthalic acid, and then reduce the dissolved impurity amount in mother liquor one time, and reduce generation and the wastewater treatment load of the water re-used.
For solving the means of problem
Usually, the purified terephthalic slurry is depressed (0.2～0.9MPa) solid-liquid separation adding, and separates mother liquor (mother liquor) and obtains with the temperature of about 120～170 ℃ under pressure.Therefore, the present inventor etc. add in this mother liquor, mix terephthaldehyde's acid crystal after, being supplied to the decompression be adjusted in subatmospheric cooling tank, bled off pressure cooling, make crystallization, thus, arrival can obtain the treatment process of the cooling suspension of the filtering feature excellence that adhesivity is improved.
In order to solve above-mentioned problem, the invention provides a kind for the treatment of process of purified terephthalic mother liquor, it is characterized in that, the crude terephthalic acid that to manufacture by the liquid-phase oxidation of p-Xylol is dissolved in the water under high temperature, high pressure, after carrying out hydrofinishing, carry out coolingly, generate the purified terephthalic slurry, while making this slurry manufacture highly purified purified terephthalic, comprise following operation:
One separation process: crystallization (primary crystallization) and the mother liquor (mother liquor) of isolating purified terephthalic from this purified terephthalic slurry;
Cooling suspension generates operation: add terephthaldehyde's acid crystal in described isolated mother liquor (mother liquor) after, being supplied to reduces pressure is adjusted into and is bled off pressure coolingly in subatmospheric cooling tank, generates thus cooling suspension; And
Secondary separation operation: carry out filtering separation under the pressure by this cooling suspension more than normal atmosphere, terephthaldehyde's acid crystal (secondary crystal) of Separation and Recovery low-purity.
In addition, it is characterized in that, in described one separation process, under pressure by this purified terephthalic slurry more than the vapour pressure of the approximately temperature of 120～170 ℃ and these slurries (approximately 0.2～0.9MPa), mother liquor (mother liquor) is separated, at described cooling suspension, generate in operation, add terephthaldehyde's acid crystal in isolated mother liquor (mother liquor) after, be supplied to and bled off pressure coolingly in the cooling tank under the decompression that is adjusted into about 1.3～53kPa (approximately 10～400mmHg), generate thus cooling suspension.
In addition, it is characterized in that, generate in operation at described cooling suspension, isolated mother liquor (mother liquor) is prepared into slurries and adds terephthaldehyde's acid crystal with the ratio of 0.05～1 % by weight with water.
In addition, it is characterized in that, generate in operation at described cooling suspension, terephthaldehyde's acid crystal that isolated mother liquor (mother liquor) is added be by the purified terephthalic crystallizing and drying crystalline powder.
In addition, it is characterized in that, in described secondary separation operation, from the purity of this cooling suspension Separation and Recovery, low terephthaldehyde's acid crystal (secondary crystal) is used as the part of raw material of the liquid phase oxidation reaction of described p-Xylol.
In addition, it is characterized in that, in described secondary separation operation, be used as dissolving the part of the water of crude terephthalic acid from the isolated mother liquor of this cooling suspension (secondary mother liquid).
In the present invention, by mother liquor of the suspension to having added in advance, mixed terephthaldehyde's acid crystal, bled off pressure cooling, be dissolved in the material of separating out in mother liquor, the such crystallinity impurity of terephthalic acid and para Toluic Acid particularly, the terephthalic acid crystalline particle that added of take is separated out or is adsorbed as core and is attached to this crystal surface, generate as the impurity that adds the growth of terephthalic acid crystalline particle, therefore think that adhesivity, filterableness are improved.
Then, low-purity terephthaldehyde's acid crystal (secondary crystal) that this cooling suspension further adheres to as impurity by filtering separation is reclaimed, but the filterableness of this suspension of the serious inequality of the size distribution of the suspension crystallization particle after growth is improved, the tack of secondary crystal also is improved, thereby can obtain the suspension of practicality.
As the part of the manufacture raw material of the terephthalic acid of the liquid-phase oxidation of p-Xylol and supply with the secondary crystal of recovery, much less the terephthalic acid that partial crystallization goes out, both made as the reaction intermediates such as para Toluic Acid of impurity also oxidized and contribute to improve the terephthalic acid utilization ratio, and, the terephthaldehyde's acid crystal that adds, mixes also is recycled recovery, without manufacturing loss.
On the other hand, isolated secondary mother liquid with do not add terephthaldehyde's acid crystal and utilize the existing isolated secondary mother liquid of method to compare, can significantly reduce as the dissolution of metals of para Toluic Acid's content of dissolved impurity and trace etc., also can increase the amount of re-using that is cycled to used in the water solvent that hydrofinishing uses.In addition, the dissolved impurity minimizing in secondary mother liquid refers to when as trade effluent, carrying out wastewater treatment, the minimizing of the carryings capacity of the environment such as oxygen requirement chemically (COD).
In addition, although any terephthalic acid all has effect to the terephthaldehyde's acid crystal added, mix, but preferably dry terephthalic acid, particularly purified terephthalic (PTA) crystallization is the use of high purity terephthalic acid's goods, to reducing para Toluic Acid's content, presents effect.Think this be because crystal surface because the drying of terephthaldehyde's acid crystal enlarges (roughness on pore, surface increases) or sensitization, the amount of adsorptive power and absorption increases, have with terephthalic acid the terephthalic acid crystal surface that the dissolved impurity of the affinity on physical chemistry is added and adsorb in a large number, the residual impurity in secondary mother liquid reduces.
Although these effects make the foreign matter content of secondary crystal increase, the intermediates such as para Toluic Acid, along with the increase of the ratio of recovery, bring desirable result to improving the phthalic acid utilization ratio.
The invention effect
According to the present invention, by by add the crystallization of terephthalic acid in mother liquor, be cooled to lower than after under normal atmosphere bleeding off pressure, carry out the simple processing operation of filtering separation formation, more remarkable to the practical function that improves these primary treatment methods of foreign matter content in the filterableness that generates Crystallization Separation, the rate of recovery that improves secondary crystal and reduction secondary mother liquid.That is, the stability increase that the improvement of filterableness makes filtration velocity improve and filter, and can make strainer less, and can carry out stable continuous or semi-continuous running.In addition, by steady running, improved the rate of recovery of secondary crystal, the equipment cost of strainer and maintain the expense of management and the labor force reduces.
In addition, owing to reclaiming the part of secondary crystal as the oxidizing reaction raw material, re-used, therefore, the raising of the rate of recovery of secondary crystal goes far towards to improve the utilization ratio of crude terephthalic acid and purified terephthalic.
And then the minimizing of the dissolved impurity of secondary mother liquid (para Toluic Acid) is related to the raising of the rate of recovery of secondary crystal, and the ratio that secondary mother liquid is cycled to used in the water that dissolves crude terephthalic acid can be increased, new dissolved water can be cut down.Therefore, wastewater treatment capacity, carrying capacity of the environment all reduce.
In addition, the minimizing of the secondary mother liquid amount recycled, much less can reduce wastewater treatment capacity, and the loads such as COD (oxygen requirement of chemistry) of waste water are reduced, and be related to the minimizing of all wastewater treatment lifting capacity, and the effect in practicality is remarkable.
In addition, owing to having reduced the dissolved impurity in the secondary mother liquid (para Toluic Acid), therefore, do not need the further processing (No. 2006-8671, JP) contacted with synthetic sorbing material, obtain the simple treatment process of effect of the present invention when being the processing with a mother liquor.
The accompanying drawing explanation
Fig. 1 means the explanatory view of the high purity terephthalic acid's who manufactures embodiment of the present invention whole operation;
Fig. 2 means from the purified terephthalic slurry manufacture high purity terephthalic acid's of embodiment of the present invention operation and the explanatory view of the treatment process of separating a mother liquor;
Fig. 3 is the explanatory view that carries out the Processing Test of the isolated mother liquor of embodiment of the present invention.
Embodiment
Below, utilize accompanying drawing to describe embodiments of the present invention.
Fig. 1 means to take the whole operation of high purity terephthalic acid's manufacture method that p-Xylol is raw material, the location of secondary crystal after processing of the present invention of the location of a mother liquor while showing the purified terephthalic Crystallization Separation, this mother liquor and secondary mother liquid and process the flow process of summary.In the manufacturing process of crude terephthalic acid (CTA), the p-Xylol of take carries out after oxidizing reaction carries out partial crystallization, utilizing solid-liquid separating machine to manufacture crude terephthalic acid (CTA) crystallization as raw material.In the manufacturing process of purified terephthalic (PTA), the CTA crystallization is prepared into to slurries in CTA slurries adjustment tank, then make that it is dissolved, hydrofinishing cooling, obtain the purified terephthalic slurry, afterwards, utilize solid-liquid separating machine 1 to be separated into PTA crystallization and a mother liquor.
By aforesaid operations, an isolated mother liquor, after adding terephthaldehyde's acid crystal, generates cooling suspension in bleeding off pressure cooling tank 13, and recycling filter 15 is separated into secondary crystal and secondary mother liquid.
Isolated secondary crystal is manufactured the part recycling of the p-Xylol of raw material as crude terephthalic acid, isolated secondary mother liquid re-uses in the part of the water solvent that dissolves the crude terephthalic acid crystallization in purified terephthalic manufacturing process.The secondary mother liquid do not re-used is processed in the wastewater treatment operation.In addition, as terephthalic acid (TA) crystallization of adding, dot the flow direction of using purified terephthalic (PTA) crystallization in a mother liquor.
Fig. 2 means to manufacture the high purity terephthalic acid's of embodiment of the present invention whole operation.Take p-Xylol when initial feed is carried out liquid-phase oxidation and hydrofinishing and manufactured the high purity terephthalic acid, utilize solid-liquid separating machine 1 to carry out solid-liquid separation adding to depress the purified terephthalic slurry, purification and recover terephthaldehyde acid crystal (primary crystallization), and it is supplied in the summary flow process via the manufacture high purity terephthalic acid of crystallizing and washing groove 2.
The summary flow process for the treatment of process of embodiment of the present invention that use has separated the mother liquor (mother liquor) of purified terephthalic crystallization (primary crystallization) is mother liquor tank 10 → slurries preparation vessel 12 → bleed off pressure flow process of cooling tank 13 → filter 15 → secondary mother liquid groove 16.In addition, in the record of the blade of stirred vessel (groove), because content is slurries or suspension, therefore set up stirrer.
Fig. 3 is the explanatory view of the Processing Test of carrying out an isolated mother liquor of embodiment of the present invention.Show following flow process: the purified terephthalic slurry generated in purified terephthalic manufacturing process is carried out to solid-liquid separation, obtain the purified terephthalic crystallization and separate mother liquor (mother liquor), afterwards, different from the treatment scheme (purified terephthalic output zone) of a mother liquor in manufacturing process, extract a mother liquor from a mother liquor tank of high temperature, high pressure, implement the inventive method (a mother liquid disposal pilot region).In addition, filtration test is to carry out to extracting sample the normal process of liquid waste disposal operation from bleeding off pressure cooling tank.
An example of embodiment of the present invention is described with Fig. 2.Adding the solid-liquid separation system of depressing the purified terephthalic slurry that (approximately 0.2～0.9MPa) carry out, as No. 47-49049, examined patent publication put down in writing, after the primary crystallization that will obtain by centrifugation or filtering separation further carries out the washing of slurry of water, again separate and reclaim the system of the crystallization of the refining terephthalic acid of high purity, be: the flow process of solid-liquid separating machine 1 → crystallizing and washing groove 2 → flash cooling groove 3 → slurries feed trough 4 → solid-liquid separating machine 5 → drying machine 6, the mother liquor that the method for embodiment of the present invention will be obtained by this system carries out as initial feed.
In addition, also can be using a mother liquor utilizing following system to obtain as initial feed, this system is that the terephthaldehyde's acid crystal after the filtering separation that JP-A is put down in writing for No. 6-506461 carries out careful water washing purification and recover terephthaldehyde acid crystal (primary crystallization) in same filter.
Both made in above-mentioned arbitrary filtering separation method, in the mother liquor obtained in the filtering separation of utilizing by filtering material, suspension suspended solid (terephthalic acid crystalline particle) in this mother liquor leaked is all trace (approximately 0.01 % by weight is following), therefore, in the situation that a mother liquor selecting filtering separation to obtain is initial feed, more expect to add, mix the effect of the embodiment of the present invention method of terephthaldehyde's acid crystal.
; in the manufacture of purified terephthalic, higher to mother liquor of the filtering separation from the purified terephthalic slurry and practical application request that the present invention is improved as the residual volume of the filterableness of the secondary crystal of problem and the dissolved impurity in secondary mother liquid.Depress (approximately 0.2～0.9MPa) dissolve the terephthalic acid of 0.1～0.5 % by weight of having an appointment in about 120～170 ℃ of mother liquors that obtain (mother liquor tank 10) adding, and be dissolved with the para Toluic Acid as impurity with the about ratio of 0.03～0.15 % by weight.
In embodiment of the present invention, add, mix terephthaldehyde's acid crystal in a mother liquor, but also can under the state of crystallization, directly add, mix, but preferably, by terephthaldehyde's acid crystal of adding for the time being water in the proper ratio (approximately 10～40 % by weight) make slurries after (slurries preparation vessel 12), be supplied to add in a mother liquor depressing (approximately 0.2～0.9MPa) with flow state and mixed.Its amount is supplied with respect to a mother liquor, to become the approximately mode of 0.05～1 % by weight, but, in order to improve the filterableness with respect to the addition of terephthaldehyde's acid crystal, preferably adds approximately 0.1～0.5 % by weight.
Wherein, although measure reduction by increasing addition to the para Toluic Acid of dissolving in secondary mother liquid, must recognize that the filtering separation of adding terephthaldehyde's acid crystal and the technical load of internal circulating load increase.
The mother liquor of suspension that is mixed with terephthaldehyde's acid crystal is used vacuum pump or injector directly to be supplied to reduce pressure into bleeding off pressure in cooling tank 13 of subatmospheric approximately 1.3～53kPa (approximately 10～400mmHg), is bled off pressure quickly, evaporates and generate the approximately suspension of 10～80 ℃.In addition, also a plurality of cooling tanks can be bled off pressure final cooling tank is decompressed to subatmospheric approximately 1.3～53kPa (approximately 10～400mmHg) by stage, generate cooling suspension.
As long as can final cooling tank be bled off pressure coolingly under the decompression of subatmospheric approximately 1.3～53kPa (approximately 10～400mmHg), generate cooling suspension, can obtain the effect of present embodiment.
With regard to final, bleed off pressure with regard to the temperature in cooling tank 13, from partial crystallization, the recovery of dissolved substance and the dissolved impurity aspect consideration that reduces the secondary mother liquid separating, preferably under subatmospheric decompression, the side that cooling temperature is low is approximately 10～80 ℃, but method in practical preferably obtains the approximately cooling suspension of 30～65 ℃ under the decompression of about 4～26kPa (approximately 30～200mmHg).
In addition, although the devaporation and being back to of evaporation bleeds off pressure in cooling tank 13, the inventor etc. also can make the evaporation and condensation water of WO2009/141968 institute motion, then make reduced para Toluic Acid's content processing water re-used.
Then, the suspension bled off pressure in cooling tank 13 utilizes strainer to be separated into secondary crystal and secondary mother liquid, but when the suspension of the minuteness particle to there being residue adhesion carries out filtering separation, preferably at the normal atmosphere of the pressure (lower than normal atmosphere) that surpasses final cooling tank or add to depress and carry out clarification filtration, can use the pressure filters such as pressure filter, FUNDABAC strainer ((strain) IHI system), Cricket strainer (month island machinery (strain) system).
As the raw material of the oxidizing reaction of carrying out p-Xylol, prepared by isolated secondary crystal, utilize acetate solvate slurried after, manufacture the part (flow direction of the secondary crystal of Fig. 1) of raw material as terephthalic acid.
Secondary mother liquid is as re-using for a part that crude terephthalic acid is dissolved and carry out the dissolved water of hydrofinishing, but the amount re-used is regulated according to the amount of dissolved impurity (para Toluic Acid) remaining in secondary mother liquid.The secondary mother liquid be not used is directly processed as waste water by methods such as current enforceable active sludge, but can further reduce wastewater treatment capacity and the load (flow direction of the secondary mother liquid of Fig. 1) of being processed.
In addition, can, by the processing such as distillation respectively of institute's motion in No. 5-58948, Unexamined Patent, reclaim the water solvent that impurity level (para Toluic Acid's content) further reduces.
Then, utilize following embodiment more specifically to describe embodiments of the present invention.But the inventive method is not limited to following embodiment.
(embodiment 1)
After the crude terephthalic acid (CTA) generated in the liquid phase air oxidation of dimethylbenzene is manufactured, the crude terephthalic acid obtained is dissolved in the water, carry out hydrofinishing under high temperature, high pressure, manufacture high purity terephthalic acid (PTA), wherein, purified terephthalic (PTA) slurry to (approximately 145 ℃, about 0.4MPa) under the high temperature that obtained by Crystallization Procedure, high pressure carries out solid-liquid separation, obtain purified terephthalic (PTA) crystallization, through washing, drying process and production purified terephthalic (PTA).
Now, the operation that the separation mother liquor obtained by above-mentioned solid-liquid separation process (mother liquor) is delivered to the liquid waste disposal under normal atmosphere via the storage tanks (mother liquor tank of high temperature, high pressure) of high temperature, high pressure is processed.
When implementing the inventive method, under high temperature, high pressure (approximately 145 ℃, about 0.4MPa), utilize branch's pipe arrangement to divide and get a mother liquor of (the mother liquid disposal pilot region of Fig. 3) high temperature of above-mentioned purified terephthalic output zone (Fig. 3), the part of a mother liquor tank of high pressure, utilize vacuum pump with the ratio of time per unit 100 weight parts to being adjusted to supplying with continuously with bleeding off pressure in cooling tank (the backflow distiller is set up) of stirrer of subatmospheric about 20kPa (about 150mmHg), this mother liquor is bled off pressure to cooling (approximately 60 ℃ of temperature).By this, bleed off pressure cooling, making to be dissolved in the solutes such as terephthalic acid in mother liquor, para Toluic Acid separates out, generate cooling suspension, be back to afterwards the liquid waste disposal operation (the purified terephthalic output zone of Fig. 3) of the mother liquor (mother liquor) in above-mentioned purified terephthalic (PTA) production, discharge continuously.
Now, in the above-mentioned branch supplying tubing of a mother liquor under high temperature, high pressure, a mother liquor is supplied with to the terephthalic acid slurries of terephthaldehyde's acid crystal (dried purified terephthalic crystallization (PTA powder)) aqueous slurry of previously prepared one-tenth 20 % by weight in the slurries preparation vessel with stirrer continuously with the ratio of 0.75 % by weight (PTA crystallization adding rate 0.15%), after a mother liquor mixes, be supplied in above-mentioned cooling tank, bled off pressure cooling.The approximately cooling suspension of 60 ℃ generated in this cooling tank is back to the wastewater treatment operation of an above-mentioned mother liquor and is discharged.
Now, extract 100 parts of cooling suspensions of discharging continuously, use the Büchner funnel equipment with warmer to carry out filtration test, carry out the mensuration of the para Toluic Acid's content in filtration time and filtered liquid (secondary mother liquid).Consequently, filtration time is 42sec, and the para Toluic Acid's content in secondary mother liquid is 0.025wt%.(table 1)
(comparative example 1)
In the method for embodiment 1, stop the interpolation (supplying with the terephthalic acid crystal water slurries of 20 % by weight) of terephthaldehyde's acid crystal, bled off pressure coolingly, generate cooling suspension.
In the same manner as in Example 1, extract this cooling suspension and carry out filtration test.Consequently, filtration time is 620sec, and para Toluic Acid's content is 0.048wt%.(table 1)
(embodiment 2)
In the method for embodiment 1, a mother liquor is supplied with to the terephthalic acid crystal water slurries of 20 % by weight with the ratio of 0.35 % by weight (PTA crystallization adding rate 0.07%), bled off pressure coolingly, generate cooling suspension.
In the same manner as in Example 1, extract this cooling suspension and carry out filtration test.Consequently, filtration time separately is 113sec, and para Toluic Acid's content is 0.033wt%.(table 1)
(embodiment 3)
In the method for embodiment 1, a mother liquor is supplied with to the terephthalic acid crystal water slurries of 20 % by weight with the ratio of 1.5 % by weight (PTA crystallization adding rate 0.3%), bled off pressure coolingly, generate cooling suspension.
In the same manner as in Example 1, extract this cooling suspension and carry out filtration test.Consequently, filtration time separately is 38sec, and para Toluic Acid's content is 0.017wt%.(table 1)
(embodiment 4)
In the method for embodiment 1, a mother liquor is supplied with to the terephthalic acid crystal water slurries of 20 % by weight with the ratio of 2.25 % by weight (PTA crystallization adding rate 0.45%), bled off pressure coolingly, generate cooling suspension.
In the same manner as in Example 1, extract this cooling suspension and carry out filtration test.Consequently, filtration time separately is 41sec, and para Toluic Acid's content is 0.011wt%.(table 1)
(embodiment 5)
In the method for embodiment 1, the wet cake that use separates from the purified terephthalic slurry (the PTA crystallization dry) carries out, the terephthalic acid crystal water slurries that prepare 20 % by weight, and with the ratio of 0.75 % by weight (PTA crystallization adding rate 0.15%), a mother liquor is supplied with, bled off pressure coolingly, generated cooling suspension.
In the same manner as in Example 1, extract this cooling suspension and carry out filtration test.Consequently, filtration time separately is 40sec, and para Toluic Acid's content is 0.032wt%.(table 1)
(embodiment 6)
In the method for embodiment 1, will bleed off pressure cooling tank pressure and be adjusted into about 7.3kPa (approximately 40 ℃ of about 55mmHg temperature), bled off pressure coolingly, generate cooling suspension.
In the same manner as in Example 1, extract this cooling suspension and carry out filtration test.Consequently, filtration time is 59sec, and para Toluic Acid's content is 0.008wt%.(table 1)
(embodiment 7)
In the method for embodiment 1, to bleed off pressure cooling tank pressure and be adjusted into about 47kPa (approximately 80 ℃ of about 355mmHg temperature), with the ratio of 1.5 % by weight (PTA crystallization adding rate 0.3%), mother liquor is supplied with the terephthalic acid crystal water slurries of 20 % by weight, bled off pressure coolingly, generated cooling suspension.
In the same manner as in Example 1, take this cooling suspension discharge opeing to carry out filtration test.Consequently, filtration time is 28sec, and para Toluic Acid's content is 0.031wt%.(table 1)
(comparative example 2)
In the method for embodiment 7, stop the interpolation (supplies of the terephthalic acid crystal water slurries of 20 % by weight) of terephthaldehyde's acid crystal, bled off pressure coolingly, generate cooling suspension.
In the same manner as in Example 1, extract this cooling suspension and carry out filtration test.Consequently, filtration time is 540sec, and para Toluic Acid's content is 0.092wt%.(table 1)
(embodiment 8)
In the method for embodiment 1, will bleed off pressure cooling tank pressure and be adjusted into about 2.4kPa (approximately 20 ℃ of about 18mmHg temperature), bled off pressure coolingly, generate cooling suspension.
In the same manner as in Example 1, extract this cooling suspension and carry out filtration test.Consequently, filtration time is 94sec, and para Toluic Acid's content is 0.003wt%.(table 1)
Table 1
Nomenclature
1,5: solid-liquid separating machine, 2: crystallizing and washing groove, 3: flash cooling groove, 4: slurries feed trough, 6: drying machine, 7: washing sump pit, 8,9,11,14: gas-liquid segregating unit, 10: mother liquor tanks, 12: slurries adjustment tank, 13: bleed off pressure cooling tank, 15: filter, 16: secondary mother liquid groove.
Claims (6)
1. the treatment process of purified terephthalic mother liquor, it is characterized in that, the crude terephthalic acid that to manufacture by the liquid-phase oxidation of p-Xylol is dissolved in the water under high temperature, high pressure, after carrying out hydrofinishing, carry out cooling, generate the purified terephthalic slurry, while from this slurry, manufacturing highly purified purified terephthalic, comprising:
One separation process: crystallization (primary crystallization) and the mother liquor (mother liquor) of isolating purified terephthalic from this purified terephthalic slurry;
Cooling suspension generates operation: add terephthaldehyde's acid crystal in described isolated mother liquor (mother liquor) after, being supplied to reduces pressure is adjusted into and is bled off pressure coolingly in subatmospheric cooling tank, generates thus cooling suspension; And
Secondary separation operation: carry out filtering separation under the pressure by this cooling suspension more than normal atmosphere, terephthaldehyde's acid crystal (secondary crystal) of Separation and Recovery low-purity.
2. the treatment process of purified terephthalic mother liquor as claimed in claim 1, it is characterized in that, in described one separation process, under pressure by this purified terephthalic slurry more than the vapour pressure of the approximately temperature of 120～170 ℃ and these slurries, (approximately 0.2～0.9MPa) separated mother liquor (mother liquor)
At described cooling suspension, generate in operation, add terephthaldehyde's acid crystal in isolated mother liquor (mother liquor) after, be supplied to adjustment cooling into about being bled off pressure in the cooling tank under the decompression of 1.3～53kPa (approximately 10～400mmHg), generate thus cooling suspension.
3. the treatment process of purified terephthalic mother liquor as claimed in claim 1 or 2, it is characterized in that, generate in operation at described cooling suspension to, isolated mother liquor (mother liquor) is prepared into slurries and adds terephthaldehyde's acid crystal with the ratio of 0.05～1 % by weight with water.
4. the treatment process of purified terephthalic mother liquor as described as any one in claim 1～3, it is characterized in that, at described cooling suspension, generate in operation, terephthaldehyde's acid crystal that isolated mother liquor (mother liquor) is added be by the purified terephthalic crystallizing and drying crystalline powder.
5. the treatment process of purified terephthalic mother liquor as described as any one in claim 1～4, it is characterized in that, in described secondary separation operation, from the purity of this cooling suspension Separation and Recovery, low terephthaldehyde's acid crystal (secondary crystal) is used as the part of raw material of the liquid phase oxidation reaction of described p-Xylol.
6. the treatment process of purified terephthalic mother liquor as described as any one in claim 1～5, it is characterized in that, in described secondary separation operation, be used as dissolving the part of the water of crude terephthalic acid from the isolated mother liquor of this cooling suspension (secondary mother liquid).
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/JP2011/053701 WO2012114434A1 (en) | 2011-02-21 | 2011-02-21 | Method for treating purified terephthalic acid mother liquor |
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| CN103443064A true CN103443064A (en) | 2013-12-11 |
| CN103443064B CN103443064B (en) | 2015-09-23 |
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| CN (1) | CN103443064B (en) |
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| WO (1) | WO2012114434A1 (en) |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01121239A (en) * | 1987-11-04 | 1989-05-12 | Idemitsu Petrochem Co Ltd | Production of aromatic carboxylic acid |
| CN1960960A (en) * | 2004-05-28 | 2007-05-09 | 三菱化学株式会社 | Method for producing high-purity terephthalic acid |
| CN101024606A (en) * | 2003-01-10 | 2007-08-29 | 三菱化学株式会社 | Method for centrifugally separating slurry containing aromatic carboxylic acid |
| CN101415667A (en) * | 2006-06-13 | 2009-04-22 | 三菱化学株式会社 | Method of drying aromatic carboxylic acid and process for producing dry aromatic carboxylic acid |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004231642A (en) * | 2003-01-10 | 2004-08-19 | Mitsubishi Chemicals Corp | Method for centrifugally separating slurry containing aromatic carboxylic acid |
| JP2006008671A (en) * | 2004-05-28 | 2006-01-12 | Mitsubishi Chemicals Corp | Method for producing high-purity terephthalic acid |
-
2011
- 2011-02-21 WO PCT/JP2011/053701 patent/WO2012114434A1/en active Application Filing
- 2011-02-21 BR BR112013020492A patent/BR112013020492A2/en not_active Application Discontinuation
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01121239A (en) * | 1987-11-04 | 1989-05-12 | Idemitsu Petrochem Co Ltd | Production of aromatic carboxylic acid |
| CN101024606A (en) * | 2003-01-10 | 2007-08-29 | 三菱化学株式会社 | Method for centrifugally separating slurry containing aromatic carboxylic acid |
| CN1960960A (en) * | 2004-05-28 | 2007-05-09 | 三菱化学株式会社 | Method for producing high-purity terephthalic acid |
| CN101415667A (en) * | 2006-06-13 | 2009-04-22 | 三菱化学株式会社 | Method of drying aromatic carboxylic acid and process for producing dry aromatic carboxylic acid |
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| BR112013020492A2 (en) | 2016-10-25 |
| WO2012114434A1 (en) | 2012-08-30 |
| CN103443064B (en) | 2015-09-23 |
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