CN1960961B - Method for producing high-purity terephthalic acid - Google Patents
Method for producing high-purity terephthalic acid Download PDFInfo
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Abstract
A method for producing high purity terephthalic acid having a step (a) of forming crude terephthalic acid, a dissolution step (b) of dissolving the crude terephthalic acid in a water solvent, a reduction step(c), a crystallization step (d), a separation step (e), a washing step (f) and a drying step (g), which further comprises a recovering step (h) wherein a solid contained in the washing wastewater discharged from the above washing step (f) is recovered and the resultant solid is fed to the above crystallization step (d) or to the above separation step (e), and a reuse step (i) wherein the washing wastewater having been subjected to the recovery of a solid in the above recovering step (h) is used as a solvent for the above dissolution step (b). The above method allows the reuse of a washing wastewater with an apparatus being compact in size, in the production of high purity terephthalic acid.
Description
Technical field
The present invention relates to high purity terephthalic acid's manufacture method.
Background technology
For obtaining high purity terephthalic acid's crystal, must from the crude terephthalic acid crystal that obtains by oxidation of p-xylene, remove intermediate product as much as possible, the by product that described intermediate product generates when being p xylene oxidation, and comprise the 4-carboxyl benzaldehyde as main component (this intermediate product is the active principle that can be converted into terephthalic acid, but with become impurity after the product terephthalic acid mixes).Given this, carry out purification step, wherein the 4-carboxyl benzaldehyde is reduced to water-soluble water-soluble highlyer, make terephthaldehyde's acid crystal then to obtain high purity terephthalic acid's crystal to toluic acid than terephthalic acid.This operation for example comprises the following step as shown in Figure 2.
At first, in dissolving step, in pulp groove 1,, make the starting slurry c of gained have High Temperature High Pressure so that crude terephthalic acid a is dissolved in the water and obtains crude terephthalic acid aqueous solution c ' thus by pump 1a and well heater 1b with crude terephthalic acid a and water b furnishing slurry.Carry out reduction step then, wherein, thus the 4-carboxyl benzaldehyde is reduced to toluic acid in the crude terephthalic acid aqueous solution c ' importing hydrogenator 2 and in the presence of catalyzer, contact with hydrogen d.The reduction reaction liquid e that comprises toluic acid and terephthalic acid that obtains is thus imported in a plurality of crystallizer tanks that are arranged in series 3 to carry out carrying out the crystalline crystallisation step by the pressure release cooling.Because the water-soluble comparison toluic acid of terephthalic acid is water-soluble low, therefore in this step, can separate out highly purified terephthalic acid crystals by adjusting crystallization condition.Carry out separating step subsequently, wherein utilize pump 3a according to circumstances to adjust pressure, the slurry f that will comprise the high-purity crystals of the terephthalic acid of separating out thus imports in the solid-liquid separator 4.Thereby described slurry is carried out solid-liquid separation, wherein separate reduction reaction mother liquor g and reclaim high purity terephthalic acid's filter cake h.H carries out cleaning step to this high purity terephthalic acid's filter cake, utilizes scavenging solution i to carry out cleaning operation in this step in washing unit 5, and carries out the filter cake k of solid-liquid separation operation to obtain to clean in solid-liquid separator 6.Further, carry out drying step, thereby wherein make the dry high purity terephthalic acid's crystal m that obtains of filter cake k of the cleaning that obtains by moisture eliminator 8.On the other hand, comprise terephthalic acid and, therefore will reclaim these active principles as much as possible owing to reduction reaction mother liquor g still contains active principles such as toluic acids.In addition, the cleaning liquid effluent j that discharges behind the described cleaning operation is once more as the solvent in the dissolving step.
In described crystallisation step,, under 120 ℃～180 ℃ service temperature, final crystallizer tank is operated usually in order to prevent that toluic acid and terephthalic acid are formed eutectic.Given this, used in the past method comprises following process: with sedimentation separating centrifuge the slurry f that obtains through crystallization is carried out solid-liquid separation under high-temperature high-pressure state, thus reduction reaction mother liquor g is separated, cleaning adding the high purity terephthalic acid's filter cake h that depresses by suspend cleaning, under normal pressure, carrying out solid-liquid separation after the pressure release once more and discharge and clean liquid effluent j gained.
In addition, in recent years, describe the manufacture method that terephthalic acid is arranged in Patent Document 1 and 2, described method comprises the simplification step that is used for purification step.In the method, under pressurized conditions, use can carry out described solid-liquid separation operation can carry out the solid-liquid separation/washing unit 7 of described cleaning operation (in the drawings, the device that is enclosed with dotted line is corresponding) again thus but make solid-liquid separation and cleaning step total implementation.In this case, the cleaning liquid effluent j that is discharged from is in high-temperature high-pressure state.
Should be owing to reason such as leakages for example taking place by cleaning screen, clean to comprise among the liquid effluent j as the part of the solids of high purity terephthalic acid's filter cake h recovery.When the scavenging solution j that comprises described solids without any processing during once more as the solvent in the pulp groove 1, then the amount of the solids of handling in the purification step system increases, but this causes increasing the constant concentration of each device size with slurry in the maintenance system.In addition, when carrying out solid-liquid separation and cleaning operation in integrated apparatus under High Temperature High Pressure, be dissolved in the amount of cleaning the terephthalic acid in the liquid effluent and increase, this also can cause the amount of intrasystem solids to increase, and device is maximized.
Patent Document 1:WO92/18454 communique
Patent Document 2:WO93/24440 communique
Summary of the invention
The problem to be solved in the present invention
Therefore, the purpose of this invention is to provide a kind of high purity terephthalic acid's manufacture method, wherein when making the high purity terephthalic acid, can utilize packaged unit to reuse the cleaning liquid effluent.
The method of dealing with problems
For addressing the above problem, the inventor has carried out deep research.As a result, they find by the solids of removing and clean the liquid effluent coexistence in advance the problems referred to above are resolved.And then also find, be recycled to the step before the separating step and can reuse this solids by the solids that will remove, and can not influence quality product.The present invention thereby be accomplished.That is, main points of the present invention are following (1)～(10).
(1) a kind of high purity terephthalic acid's manufacture method, described method comprises:
The manufacturing step of crude terephthalic acid (a) wherein makes p xylene oxidation comprise the crude terephthalic acid of 4-carboxyl benzaldehyde with manufacturing;
Dissolving step (b), wherein under High Temperature High Pressure, make described crude terephthalic acid manufacturing step (a) thus in the described crude terephthalic acid that obtains be dissolved in the aqueous solution that obtains described crude terephthalic acid in the water solvent;
Reduction step (c) is wherein reduced the described 4-carboxyl benzaldehyde in the described crude terephthalic acid aqueous solution to obtain as the reduction reaction mixed solution to toluic acid with hydrogen in the presence of catalyzer;
Crystallisation step (d) wherein is cooled to described reduction reaction mixed solution 120 ℃～200 ℃ so that slurry is separated out and obtained thus in the crystallization of described terephthalic acid;
Separating step (e) wherein carries out solid-liquid separation to described slurry and comprises terephthalic acid cake and the reduction reaction mother liquor of described terephthalic acid crystals as main component so that described slurry is divided into;
Cleaning step (f) wherein utilizes scavenging solution that described terephthalic acid cake is cleaned;
Drying step (g) wherein makes the described filtration cakes torrefaction that cleans in the described cleaning step (f) to obtain high purity terephthalic acid's crystal;
Described method also comprises:
Recycling step (h), wherein the solids that comprises in the cleaning liquid effluent that will be discharged by described cleaning step (f) reclaims and described solids is delivered to described crystallisation step (d) or separating step (e); With
Utilize step (i) again, wherein use and in described recycling step (h), reclaimed the solvent of the cleaning liquid effluent of solids as described dissolving step (b).
(2) manufacture method of the high purity terephthalic acid described in above-mentioned (1) wherein in described recycling step (h), will reclaimed described solids by the described cleaning liquid effluent cooling back that described cleaning step (f) is discharged.
(3) manufacture method of the high purity terephthalic acid described in above-mentioned (2), wherein the temperature of the described cleaning liquid effluent of being discharged by described cleaning step (f) is above 100 ℃, and be cooled to after 0 ℃～100 ℃ at described cleaning liquid effluent, therefrom reclaim described solids.
(4) manufacture method of the high purity terephthalic acid described in above-mentioned (2) or (3) is wherein cooled off described cleaning liquid effluent by the pressure release evaporation.
(5) as the manufacture method of each described high purity terephthalic acid in above-mentioned (1)～(4), wherein the recovery of the described solids in described recycling step (h) is undertaken by cyclonic separator or thickner.
(6) as the manufacture method of each described high purity terephthalic acid in above-mentioned (1)～(5), wherein said separating step (e) carries out under than the higher pressure of the pressure in the final crystallizer tank in the described crystallisation step (d).
(7) as the manufacture method of each described high purity terephthalic acid in above-mentioned (1)～(6), wherein said separating step (e) and described cleaning step (f) utilize integrated apparatus to carry out.
(8) manufacture method of the high purity terephthalic acid described in above-mentioned (7), the described integrated apparatus that wherein is used for implementing described separating step (e) and described cleaning step (f) is any of sedimentation separating centrifuge, rotary pressure strainer and horizontal belt strainer.
(9) as the manufacture method of each described high purity terephthalic acid in above-mentioned (1)～(8), wherein the described solids that contains in the described cleaning liquid effluent by described cleaning step (f) discharge is for being supplied to the 1 weight %～10 weight % of the described terephthalic acid crystals that comprises in the slurry of described separating step (e).
(10) as the manufacture method of each described high purity terephthalic acid in above-mentioned (1)～(8), wherein said crystallisation step (d) is made of the crystallizer tank with layout more than 2 sections, and the described solids that will reclaim in described recycling step (d) is delivered to the described final crystallizer tank in the crystallizer tank of arranging more than 2 sections.
According to the present invention, a kind of high purity terephthalic acid's manufacture method can be provided, wherein when making the high purity terephthalic acid, can utilize packaged unit to reuse the cleaning liquid effluent.
Description of drawings
Fig. 1 is the schema of description according to the embodiment of high purity terephthalic acid's of the present invention manufacture method.
Fig. 2 is the schema of an example of describing traditional high purity terephthalic acid's manufacture method.
Description of reference numerals
1,11: the pulp groove
1a, 11a: pump
1b, 11b: well heater
2,12: hydrogenator
3,13: crystallizer tank
3a, 13a: pump
4,6: solid-liquid separator
5: washing unit
7,17: solid-liquid separation/washing unit
8,18: moisture eliminator
19: water cooler
20: separator
A, A: crude terephthalic acid
B, B: water
C, C: starting slurry
C ', C ': the crude terephthalic acid aqueous solution
D, D: hydrogen
E, E: reduction reaction mixed solution
F, F: slurry
G, G: reduction reaction mother liquor
H: high purity terephthalic acid's filter cake
I, I: scavenging solution
J, J: clean liquid effluent
K: the filter cake of cleaning
K: high purity terephthalic acid's filter cake
M, M: high purity terephthalic acid's crystal
N: the slurry of recovery
O: the solids of recovery
P: the waste liquid of recovery
Embodiment
Below with the present invention is described in detail.
High purity terephthalic acid's of the present invention manufacture method comprises:
The manufacturing step of crude terephthalic acid (a) wherein makes p xylene oxidation comprise the crude terephthalic acid of 4-carboxyl benzaldehyde with manufacturing;
Dissolving step (b), wherein under High Temperature High Pressure with the manufacturing step (a) of described crude terephthalic acid thus in the described crude terephthalic acid that obtains be dissolved in the aqueous solution that obtains described crude terephthalic acid in the water solvent;
Reduction step (c) is wherein reduced to obtain as the reduction reaction mixed solution to toluic acid to the described 4-carboxyl benzaldehyde in the aqueous solution of described crude terephthalic acid with hydrogen in the presence of catalyzer;
Crystallisation step (d) wherein is cooled to described reduction reaction mixed solution 120 ℃～200 ℃ so that described terephthaldehyde's acid crystal also obtains slurry thus;
Separating step (e) wherein carries out solid-liquid separation to described slurry and comprises terephthalic acid cake and the reduction reaction mother liquor of described terephthalic acid crystals as main component so that described slurry is divided into;
Cleaning step (f) wherein utilizes scavenging solution that described terephthalic acid cake is cleaned;
Drying step (g), it is dry to obtain high purity terephthalic acid's crystal that the described filter cake that cleans in the described cleaning step (f) is carried out;
Described method is characterised in that also and comprises:
Recycling step (h), wherein the solids that comprises in the cleaning liquid effluent that will be discharged by described cleaning step (f) reclaims and described solids is delivered to described crystallisation step (d) or separating step (e); With
Utilize step (i) again, wherein use and in described recycling step (h), reclaimed the solvent of the cleaning liquid effluent of solids as described dissolving step (b).Describe with reference to 1 pair of manufacture method of the present invention of figure.
Be meant terephthalic acid below the term " active principle " and can change other compounds of terephthalic acid into, and comprise dissolved constituent simultaneously and separate out component by for example oxidizing reaction etc.In addition, term " solids " is meant the component of separating out in the active principle.
At first, in the manufacturing step (a) of crude terephthalic acid, in the presence of catalyzer, in acetic acid solvent with molecular oxygen with p-Xylol oxidation in liquid phase, generate crude terephthalic acid thus.This step is well-known, and uses the known traditional catalyst of using in this reaction.The example of described known traditional catalyst comprises, such as heavy metal compounds such as cobalt compound, manganic compound, iron cpd and chromium cpd and bromine compounds etc.In reaction system, these compounds exist with dissolved state.The wherein preferably combination of cobalt compound or manganic compound and bromine compounds.In this case, these compounds use with such amount usually, so that the amount of cobalt atom, manganese atom and bromine atoms is respectively 10ppm～5 with respect to solvent, and 000ppm, 10ppm～5,000ppm and 10ppm～10,000ppm.
Usually use and comprise the gaseous mixture of rare gas element and oxygen as molecular oxygen.For example, use air or oxygen-rich air.The molecular oxygen that is delivered to reactor is generally 3 times～20 times, preferred 2 times～4 times with respect to the mol ratio of p-Xylol.
The p-Xylol that is supplied to reactor is generally 1 weight %～50 weight % with respect to the ratio of acetate.The concentration of water is generally 5 weight %～20 weight % in the reaction system, preferred 5 weight %～15 weight %.
The temperature of oxidizing reaction is generally 160 ℃～260 ℃, preferred 170 ℃～210 ℃.Pressure can be to make reaction system keep liquid any pressure under described temperature of reaction.Pressure is generally 0.5MPa～5MPa, preferred 1MPa～2MPa.Residence time is generally 10 minutes～and 200 minutes.
Terephthalic acid is difficult for being dissolved in the acetate as solvent.Therefore, the terephthalic acid that generates in the oxidation step is separated out as crystal and is formed slurry.Yet the amount of solvent, temperature of reaction and pressure are depended in the dissolving of terephthalic acid.In this case, for example be used to cool off the crystallisation step of reaction mixture etc., and form slurry thus so that terephthalic acid is separated out.This slurry is carried out the solid-liquid separation operation to obtain the crude terephthalic acid crystal.Although the terephthalic acid slurry that obtains in oxidation step is in pressurized state, can directly carry out solid-liquid separation to this slurry, or carry out pressure release cooling etc., carry out solid-liquid separation then.For the method for solid-liquid separation, can use any method, as long as this method can make crystal separate with mother liquor.The example of the method for described solid-liquid separation comprises filtration and centrifugation etc.If desired, can clean and drying.Obtain the crude terephthalic acid crystal thus.
Term among the present invention " crude terephthalic acid " is meant with 1,000ppm～10, and the amount of 000ppm comprises the terephthalic acid of 4-carboxyl benzaldehyde.
In dissolving step (b), crude terephthalic acid A (crude terephthalic acid that comprises the 4-carboxyl benzaldehyde that obtains by cacodyl oxide benzene) is delivered to pulp groove 11, and it is dissolved among the water B.Described crude terephthalic acid A is by obtaining p xylene oxidation in aliphatic carboxylic acid solvents such as for example acetate.This crude terephthalic acid comprise one of them alkyl not by the intermediate product of complete oxidation as by product, 4-carboxyl benzaldehyde etc. for example.For making described highly purified terephthalic acid, must from crude terephthalic acid A, remove these impurity as much as possible.
The solubleness of terephthalic acid in water is very low.Thereby must be in pulp groove 11 water B with crude terephthalic acid A furnishing slurry, thereby and utilize pump 11a and well heater 11b that the starting slurry C of gained is regulated so that it has High Temperature High Pressure described terephthalic acid can be dissolved in the water.Temperature in this high-temperature and high-pressure conditions depends on slurry concentration.Yet described temperature should be preferably 230 ℃～320 ℃ more than 200 ℃ and below the temperature that device can tolerate; And the pressure in the described high-temperature and high-pressure conditions must be the pressure that can keep liquid phase under described temperature range, is preferably 2.8MPa～11.3MPa.
The concentration of the slurry of gained is generally 20 weight %～40 weight % in dissolving step (b), is preferably 25 weight %～35 weight %.The too high meeting of slurry concentration causes occurring in the device stopping up; Slurry concentration is crossed to hang down and then can be caused the mother liquor amount to increase, and the device that then is suitable for this manufacture needs to maximize.Consider from the angle that prevents to stop up, preferably keep the constant slurry concentration.
In reduction step (c) subsequently, the aqueous solution C ' of the crude terephthalic acid that will obtain through described dissolving step (b) is delivered to hydrogenator 12, and utilizes the hydrogen D that imports to make it carry out catalytic reduction in the presence of catalyzer to obtain reduction reaction mixed solution E thus.Condition in catalyzer and the hydrogenator 12 should make described 4-carboxyl benzaldehyde reduction and can not make described terephthalic acid reduction.Its objective is that the described 4-carboxyl benzaldehyde that contains among the aqueous solution C ' with crude terephthalic acid is reduced to higher to toluic acid than described terephthalic acid of solubleness in water.Preferably farthest carry out this reduction reaction.Described hydrogenation reaction also is known.As hydrogenation catalyst, can use the catalyzer that comprises such as the metal of ruthenium, rhodium, palladium, platinum or osmium grade in an imperial examination 8～10 families (according to IUPAC Nomenclature ofInorganic Chemistry, revised edition in 1998).This catalyzer is carrier loaded by for example gac etc. usually, and uses with the form of fixed bed.Preferred in these catalyzer by activated carbon supported palladium.Temperature in the hydrogenation reaction is generally 260 ℃～320 ℃, is preferably 270 ℃～300 ℃, and the dividing potential drop of hydrogen is generally 0.5kg/cm
2G～20kg/cm
2G.
In addition, in crystallisation step (d), the reduction reaction mixed solution E that obtains in the described reduction step (c) is imported in the crystallizer tank 13.Temperature and pressure reduced to make described toluic acid is kept the dissolved degree, thereby make described terephthaldehyde's acid crystal and obtain slurry F.At this, wish that with multistage, preferably 3 sections～6 sections crystallizer tanks 13 are arranged in series, and make pressure reduce step by step and make described terephthaldehyde's acid crystal with reaction mixture E (by pressure release transpiration cooling).Although in Fig. 1, be provided with 2 crystallizer tanks 13,3 above crystallizer tanks can be set also.Can with as the temperature regulation of the final crystallizer tank of crystallizer tank 13 last groove to not forming eutectiferous temperature condition with terephthalic acid to toluic acid.Specifically, preferred 120 ℃～200 ℃ of described temperature, more preferably 130 ℃～180 ℃.Preferred 0.20MPa～the 1.56MPa of pressure in this situation, more preferably 0.27MPa～1.00MPa.
Then, in separating step (e), under the pressure that the pressure of the slurry of gained is higher in than crystallisation step (d) described slurry F imported in the solid-liquid separator separating reduction reaction mother liquor G, and obtain comprising high purity terephthalic acid's filter cake of highly purified described terephthalic acid crystals.In addition, carry out cleaning step (f), wherein when keeping pressurized state, this high purity terephthalic acid's filter cake is cleaned.Preferred use can be implemented the solid-liquid separation/washing unit 17 of separating step (e) and cleaning step (f) simultaneously as the solid-liquid separator in this operation.Adopt this device can simplify series of steps.
When only using solid-liquid separation/washing unit 17 to carry out described separating step (e) and described cleaning step (f), its process is as follows.Slurry F and scavenging solution I are imported in solid-liquid separation/washing unit 17.Usually, the water of temperature more than the service temperature of solid-liquid separation/washing unit 17 is used as scavenging solution I.After the solid-liquid separation of carrying out slurry F, in same device, the filter cake of gained is cleaned immediately with scavenging solution I.Then, with the separation of high purity terephthalic acid's filter cake and the taking-up of cleaning, and discharge reduction reaction mother liquor G and the main cleaning liquid effluent J that constitutes by the composition of scavenging solution I.
The service temperature of described solid-liquid separation/washing unit 17 equals the interior temperature of final crystallizer tank in the described crystallisation step (d), and is preferably 120 ℃～200 ℃, more preferably 130 ℃～180 ℃.For pressure, for the temperature that suppresses to be caused by pressure release descends, (operation) pressure must be than the pressure height of the final crystallizer tank in the crystallisation step (d) in addition.Specifically, the pressure in the device 17 is preferably than the high 0MPa～1MPa of pressure in the final crystallizer tank of crystallisation step (d).When further reducing pressure when described reaction mixture carries out crystallization in described final crystallizer tank after, cool off by the pressure release evaporation, the component that is dissolved in the mother liquor is separated out.This causes trouble in the time of may carrying out separating step (e) in solid-liquid separation/washing unit 17.On the other hand, pressure is risen so high then need intensifier so that it is high pressure resistant.The example that is used for integrating the solid-liquid separation/washing unit 17 that carries out above-mentioned solid-liquid separation and cleaning comprises sedimentation separating centrifuge, rotary pressure strainer and horizontal belt strainer etc., preferred especially sedimentation-filtration dewatering separating centrifuge.
At drying step (g) thus in use 18 pairs in moisture eliminator to obtain thus high purity terephthalic acid's filter cake K carry out drying and remove the residual liquid that adheres to.Thereby, can obtain high purity terephthalic acid's crystal M.The example of moisture eliminator 18 comprises steam tube dryer and fluidized bed dryer etc.Also can use following method: with high purity terephthalic acid's filter cake K pressure release of High Temperature High Pressure so that at least a portion sticks to the solvent composition evaporation on this filter cake.The example of described moisture eliminator 18 comprises spin drier and fluidized bed type moisture eliminator etc.Can in the presence of flowing gas, use water vapour etc. as thermal source, when dry outlet operating temperature (OUT) is 70 ℃～180 ℃, implement dry.
On the other hand, also comprise all terephthalic acids as described and described among the reduction reaction mother liquor G, must reclaim these active principles as much as possible described active principles such as toluic acids.The example of recovery method comprises following method: mother liquor G is imported in one or more pressure release cooling tanks; Thereby cooling mother liquor G obtains slurry so that the active principle that wherein comprises is separated out; Slurry is filtered it is divided into secondary mother liquid and secondary crystal; Secondary crystal is imported in the oxidation step, and wherein oxidation dialkyl aromatic compound is to obtain described thick aromatic carboxylic acid; In pulp groove 11, use secondary mother liquid to replace described water B directly or indirectly or in described cleaning step (f), use secondary mother liquid as scavenging solution.
In addition, regulate described pressure release cooling tank, and the boiling point of the main component of the described liquid under the pressure in this groove is not higher than the temperature of the described liquid before importing so that the pressure that its pressure ratio that has is imported into liquid wherein is low.In the time of in liquid being imported this pressure release cooling tank, the partially liq evaporation, remaining liquid cooling is to the boiling point under the pressure after the variation.In this operation, when liquid was solution, the solute that surpasses cooled solubleness part was separated out.
In addition, also comprise above-mentioned active principle among the cleaning liquid effluent J (term among the present invention " cleaning liquid effluent " is meant with scavenging solution the terephthalic acid cake that obtains by solid-liquid separation is cleaned the liquid that discharge the back).Especially when adopt solid-liquid separation/washing unit 17 therein stable integration carry out solid-liquid separation and when cleaning, be not dissolved in the described solids that cleans among the liquid effluent J and be easy to sneak into and clean among the liquid effluent J.The amount of this solids is preferably the 1 weight %～10 weight % of the terephthalic acid crystals of the described slurry F that is supplied to solid-liquid separation/washing unit 17, more preferably 3 weight %～8 weight %.Reduce in the situation that is lower than 1 weight % at the content of attempting solids, have the operation of the solid-liquid separation/washing unit 17 unsettled possibility that becomes.On the other hand, surpass in the situation of 10 weight %,, solid-liquid separation/washing unit 17 is maximized in order to obtain described high purity terephthalic acid's crystal M of aequum at the content of solids.
In described recycling step (h), from clean liquid effluent J, reclaim active principle as much as possible as described solids.In addition, owing to clean the temperature very high (usually above 100 ℃) of liquid effluent J, therefore wherein except comprising the active principle that exists with dissolved state in a large number as also comprising the active principle of solids.Thereby preferred cooling is cleaned liquid effluent J so that described dissolved active principle is separated out.More preferably will clean liquid effluent J is cooled to below 100 ℃.Yet the temperature that cleaning liquid effluent J is cooled to should not be lower than the zero pour of cleaning liquid effluent J, is preferably 60 ℃～100 ℃.In the too high situation of cooling temperature, can not fully reclaim and be dissolved in the terephthalic acid that cleans in the liquid effluent.In addition, in the low excessively situation of cooling temperature, in dissolving step (b), reuse the energy that need be used for preheating when cleaning liquid effluent, and device needs to maximize.Can utilize water cooler 19 (pressure release cooling tank) to cool off, or cool off by heat exchange.Consider that from the angle of simplification device preferred applying pressure discharges cooling tank.By utilizing injector etc. and operation under reduced pressure can realize cooling less than 100 ℃.
The preferred utilization reclaimed solids such as cyclonic separator (centrifugal settler) or thickner separators 20 such as (precipitation/thickeners) from the slurry N that is recovered, the active principle in the wherein said slurry has carried out crystallization by described cooling.The solids O through reclaiming that reclaims thus (is for example imported described crystallisation step (d), crystallizer tank 13) or described separating step (e) (for example, solid-liquid separation/washing unit 17) (also solids O not only can be imported crystallisation step (d) but also import separating step (e)).Particularly when the described crystallizer tank 13 of described crystallisation step (d) adopts a plurality of crystallizer tank, more preferably solids O is imported in the described final crystallizer tank.
Described crystallizer tank 13 and solid-liquid separation/washing unit 17 can be operated under the described temperature, pressure condition that toluic acid dissolving and terephthalic acid are separated out, thereby when making described terephthalic acid keep precipitation state, make described to toluic acid dissolving and with above-mentioned solids separation, and with reduction reaction mother liquor G or clean liquid effluent J and discharge.Thereby the most described terephthalic acid that comprises in the described solids can be used as high purity terephthalic acid's crystal M and obtains.
In utilizing step (i) again, the solids that wherein comprises reclaimed the cleaning liquid effluent removed and be supplied to pulp groove 11 in the dissolving step (b) in recycling step (h) as the part of water B.
The present invention is described in detail below with reference to embodiment.
Embodiment
To comprise p-Xylol and catalyzer (acetic acid solution of cobaltous acetate and manganous acetate and hydrogen bromide) acetic acid solution, will by the solid-liquid separation step of back reclaim separate mother liquor and air is continuously supplied to steel basin.In service temperature is that 190 ℃ and working pressure are 1.23MPa (absolute pressure), the control liquid level so that the residence time be to carry out oxidizing reaction simultaneously under 1 hour the condition.In addition, use the condenser arranged with multistage outlet temperature with distilled steam cooling to 40 ℃.Discharge gas so that the concentration of oxygen is operated device when being 2.5 volume % in control.In addition, will mix by the condensation product that each condenser obtains and be back in the oxidation reactor, and discharge the partial condensation thing so that the moisture concentration that the mother liquor in the slurry that discharge the reaction back has is 10 weight %.The slurry concentration of the slurry of being discharged by oxidation reactor is 35 weight %, and the concentration of the cobalt/manganese in the reaction mother liquor/bromine is 300/300/1,000 ppm by weight.
To together be continuously supplied to steel basin by slurry and the air that oxidation reactor is discharged.In service temperature is that 181 ℃ and working pressure are 1.15MPa (absolute pressure), the control liquid level so that the residence time be to carry out the additional oxidizing reaction of low temperature simultaneously under 15 minutes the condition.The condenser that use is arranged with multistage is with the outlet temperature of distilled steam cooling to 40 ℃.Discharge gas so that the concentration of oxygen is operated device when being 6 volume % in control.To mix and be back to the additional oxidation reactor of low temperature by the condensation product that each condenser obtains.
To be cooled to 90 ℃ to carry out crystallization by the slurry that the additional oxidation reactor of low temperature is discharged.The slurry of gained after the crystallization is supplied to rotary vacuum filter to carry out solid-liquid separation and cleaning.Working pressure in this operation is a normal atmosphere.With the steam-type rotatory drier isolating crude terephthalic acid filter cake is carried out drying to obtain the crude terephthalic acid crystal.
This crude terephthalic acid is implemented the manufacturing step of the high purity terephthalic acid shown in Fig. 1.At first, in the pulp groove 11 in dissolving step (b), make water B obtain to comprise the starting slurry C of the crude terephthalic acid of 30 weight % as solvent.Utilizing pump 11a and well heater 11b that this slurry is converted into temperature is 290 ℃, the pressure High Temperature High Pressure crude terephthalic acid aqueous solution C ' for 8.54MPa, and this solution is delivered to hydrogenator 12 in the reduction step shown in Fig. 1 (c).In hydrogenator 12, in the presence of palladium catalyst, under 290 ℃ and 8.54MPa, described crude terephthalic acid aqueous solution C ' is reduced processing with hydrogen D.
In follow-up crystallisation step (d), use the crystallizer tank 13 that 5 crystallizer tanks are arranged in series to carry out the pressure release evaporation step by step.Thereby pressure and temperature is finally reduced to 0.63MPa and 161 ℃ respectively, with the crystallization terephthalic acid.Use sedimentation separating centrifuge as follows the slurry F that obtains by crystallization to be handled as solid-liquid separation/washing unit 17.At first, in separating step (e), slurry F is separated into terephthalic acid cake and reduction reaction mother liquor G by solid-liquid separation.Subsequently, in cleaning step (f), water carries out clean and reclaims high purity terephthalic acid's filter cake K isolating described terephthalic acid cake as scavenging solution I.The operational condition that is used for this solid-liquid separation/washing unit 17 comprises the pressure of 0.73MPa and 161 ℃ temperature.Supply temperature as the water of scavenging solution I is 161 ℃.In addition, to operate isolating terephthalic acid cake with respect to every weight part by solid-liquid separation be 0.8 weight part to the consumption of scavenging solution.
The cleaning liquid effluent J that is discharged by wash section comprises the solids that leaks through screen cloth, and the content of this solids is suitable with the 5 weight % that are supplied to the solids that comprises among the slurry F of solid-liquid separation/washing unit 17.Cleaning liquid effluent J also comprises with the amount that is equivalent to 0.3 weight % and is dissolved in wherein terephthalic acid.Carry out recycling step (h) thus, wherein will clean liquid effluent J and import in the condenser 19, thereby relief pressure is to normal pressure and be cooled to 100 ℃ and make and be dissolved in the terephthalic acid that cleans among the liquid effluent J and separate out.Afterwards, utilize thickner (settlement separator) 20, reclaim the terephthalic acid crystals that comprises among the described cleaning liquid effluent J as the solids O that reclaims.
Make to comprise high purity terephthalic acid's crystalline and reclaim the final crystallizer tank that solids O is back to crystallisation step (d), and the waste liquid P that will therefrom reclaim the recovery of solids is delivered to pulp groove 11 in the dissolving step (b) as the solvent that is used for dissolving step (b).Based on the amount of the crude terephthalic acid that is supplied to pulp groove 11, the amount of the solids O of the recovery of Shu Songing is equivalent to 5 weight % thus.
Comparative example
Directly be delivered to the pulp groove 11 in the dissolving step (b) and be not delivered to the recycling step (h) except cleaning liquid effluent J, carry out with embodiment in identical process.
The result
In the method according to the invention, reclaim, cleaning liquid effluent J is back in the pulp groove 11, the amount that is delivered to the terephthalic acid of pulp groove 11 can be reduced by 5 weight % by cleaning the solids that comprises among the liquid effluent J in advance.Therefore, needn't full-scale plant be maximized in order in manufacturing step, to keep given slurry concentration.
Although at length describe the present invention, it is obvious to the skilled person that and to carry out various changes and modifications and not break away from its spirit and scope the present invention with reference to specific embodiment of the present invention.
The Japanese patent application that the application submitted to based on May 28th, 2004 (special hope 2004-159897), its content is introduced by reference at this.
Industrial applicibility
The invention provides a kind of high purity terephthalic acid's manufacture method, wherein when making the high purity terephthalic acid, can in midget plant, reuse to clean and discharge liquid. The present invention has important industrial value.
Claims (10)
1. a high purity terephthalic acid manufacture method, described method comprises:
The manufacturing step of crude terephthalic acid (a) wherein makes p xylene oxidation comprise the crude terephthalic acid of 4-carboxyl benzaldehyde with generation, and described crude terephthalic acid is meant with 1,000ppm～10, and the amount of 000ppm comprises the terephthalic acid of 4-carboxyl benzaldehyde;
Dissolving step (b), wherein under the condition of 200 ℃～320 ℃ and 2.8MPa～11.3MPa, make described crude terephthalic acid manufacturing step (a) thus in the described crude terephthalic acid that obtains be dissolved in the aqueous solution that obtains described crude terephthalic acid in the water solvent;
Reduction step (c) is wherein reduced to obtain the reduction reaction mixed solution to the described 4-carboxyl benzaldehyde in the aqueous solution of described crude terephthalic acid with hydrogen in the presence of catalyzer;
Crystallisation step (d) wherein is cooled to described reduction reaction mixed solution 120 ℃～200 ℃ so that described terephthaldehyde's acid crystal also obtains slurry thus;
Separating step (e) wherein carries out solid-liquid separation to described slurry and comprises terephthalic acid cake and the reduction reaction mother liquor of described terephthalic acid crystals as main component so that described slurry is divided into;
Cleaning step (f) wherein utilizes scavenging solution that described terephthalic acid cake is cleaned;
Drying step (g), it is dry to obtain high purity terephthalic acid's crystal that the described filter cake that cleans in the described cleaning step (f) is carried out;
Described method also comprises:
Recycling step (h), wherein the solids that comprises in the cleaning liquid effluent that will be discharged by described cleaning step (f) reclaims, and the gained solids is delivered to described crystallisation step (d) or separating step (e); With
Utilize step (i) again, wherein use and in described recycling step (h), reclaimed the solvent of the cleaning liquid effluent of solids as described dissolving step (b).
2. high purity terephthalic acid's as claimed in claim 1 manufacture method wherein in described recycling step (h), will reclaimed described solids by the described cleaning liquid effluent cooling back that described cleaning step (f) is discharged.
3. high purity terephthalic acid's as claimed in claim 2 manufacture method, wherein the temperature of the described cleaning liquid effluent of being discharged by described cleaning step (f) is above 100 ℃, and, therefrom reclaim described solids in that described cleaning liquid effluent is cooled to after 0 ℃～100 ℃.
4. high purity terephthalic acid's as claimed in claim 2 manufacture method is wherein cooled off described cleaning liquid effluent by the pressure release evaporation.
5. high purity terephthalic acid's as claimed in claim 1 manufacture method, wherein the recovery of the described solids in described recycling step (h) is undertaken by cyclonic separator or thickner.
6. high purity terephthalic acid's as claimed in claim 1 manufacture method, wherein said separating step (e) carries out under than the higher pressure of the pressure of the final crystallizer tank of described crystallisation step (d).
7. high purity terephthalic acid's as claimed in claim 1 manufacture method, wherein said separating step (e) and described cleaning step (f) utilize integrated apparatus to carry out.
8. high purity terephthalic acid's as claimed in claim 7 manufacture method, the described integrated apparatus that wherein is used for implementing described separating step (e) and described cleaning step (f) is any of sedimentation separating centrifuge, rotary pressure strainer and horizontal belt strainer.
9. high purity terephthalic acid's as claimed in claim 1 manufacture method, wherein the described solids that contains in the described cleaning liquid effluent of being discharged by described cleaning step (f) is the 1 weight %～10 weight % of the described terephthalic acid crystals that comprises in the slurry that is supplied to described separating step (e).
10. high purity terephthalic acid's as claimed in claim 1 manufacture method, wherein said crystallisation step (d) is made of the crystallizer tank with layout more than 2 sections, and the described solids that will reclaim in described recycling step (h) is delivered to the described final crystallizer tank in the crystallizer tank of arranging more than 2 sections.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004159897 | 2004-05-28 | ||
| JP159897/2004 | 2004-05-28 | ||
| PCT/JP2005/009462 WO2005115957A1 (en) | 2004-05-28 | 2005-05-24 | Method for producing high purity terephthalic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1960961A CN1960961A (en) | 2007-05-09 |
| CN1960961B true CN1960961B (en) | 2011-06-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2005800174106A Active CN1960961B (en) | 2004-05-28 | 2005-05-24 | Method for producing high-purity terephthalic acid |
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| Country | Link |
|---|---|
| CN (1) | CN1960961B (en) |
| WO (1) | WO2005115957A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3188817B1 (en) * | 2014-07-25 | 2021-04-28 | Ineos Us Chemicals Company | Rotary pressure filter apparatus with reduced pressure fluctuations |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1064675A (en) * | 1991-02-05 | 1992-09-23 | 帝国化学工业公司 | The preparation method of terephthalic acid |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11335321A (en) * | 1998-05-22 | 1999-12-07 | Mitsui Chem Inc | Production of aromatic carboxylic acid |
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- 2005-05-24 WO PCT/JP2005/009462 patent/WO2005115957A1/en active Application Filing
- 2005-05-24 CN CN2005800174106A patent/CN1960961B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1064675A (en) * | 1991-02-05 | 1992-09-23 | 帝国化学工业公司 | The preparation method of terephthalic acid |
Non-Patent Citations (1)
| Title |
|---|
| JP特开平11-335321A 1999.12.07 |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2005115957A1 (en) | 2005-12-08 |
| CN1960961A (en) | 2007-05-09 |
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