CN101186573B - Process for producing terephthalic acid - Google Patents
Process for producing terephthalic acid Download PDFInfo
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- CN101186573B CN101186573B CN2007101609799A CN200710160979A CN101186573B CN 101186573 B CN101186573 B CN 101186573B CN 2007101609799 A CN2007101609799 A CN 2007101609799A CN 200710160979 A CN200710160979 A CN 200710160979A CN 101186573 B CN101186573 B CN 101186573B
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- terephthalic acid
- filter cake
- liquid
- preparation
- solid
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- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 title claims abstract description 324
- 238000000034 method Methods 0.000 title claims abstract description 30
- 230000008569 process Effects 0.000 title abstract description 16
- 239000007788 liquid Substances 0.000 claims abstract description 126
- 238000000926 separation method Methods 0.000 claims abstract description 37
- 238000001704 evaporation Methods 0.000 claims abstract description 23
- 230000008020 evaporation Effects 0.000 claims abstract description 20
- 239000012065 filter cake Substances 0.000 claims description 124
- 238000005406 washing Methods 0.000 claims description 85
- 239000012452 mother liquor Substances 0.000 claims description 65
- 239000013078 crystal Substances 0.000 claims description 49
- 238000002360 preparation method Methods 0.000 claims description 45
- 239000002002 slurry Substances 0.000 claims description 45
- 238000006243 chemical reaction Methods 0.000 claims description 41
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 claims description 32
- 238000007254 oxidation reaction Methods 0.000 claims description 31
- 239000002904 solvent Substances 0.000 claims description 30
- 230000003647 oxidation Effects 0.000 claims description 24
- 239000012535 impurity Substances 0.000 claims description 19
- 238000002425 crystallisation Methods 0.000 claims description 13
- URLKBWYHVLBVBO-UHFFFAOYSA-N Para-Xylene Chemical group CC1=CC=C(C)C=C1 URLKBWYHVLBVBO-UHFFFAOYSA-N 0.000 claims description 12
- 230000009467 reduction Effects 0.000 claims description 11
- 230000008025 crystallization Effects 0.000 claims description 10
- 239000003125 aqueous solvent Substances 0.000 claims description 9
- 239000001257 hydrogen Substances 0.000 claims description 7
- 229910052739 hydrogen Inorganic materials 0.000 claims description 7
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 5
- 229910001882 dioxygen Inorganic materials 0.000 claims description 5
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 abstract description 4
- 125000003118 aryl group Chemical group 0.000 abstract description 4
- 150000001875 compounds Chemical class 0.000 abstract description 3
- 230000001464 adherent effect Effects 0.000 abstract 1
- 238000004140 cleaning Methods 0.000 abstract 1
- -1 e.g. Chemical compound 0.000 abstract 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 33
- 238000012216 screening Methods 0.000 description 26
- 238000006722 reduction reaction Methods 0.000 description 25
- 235000012970 cakes Nutrition 0.000 description 20
- 230000001590 oxidative effect Effects 0.000 description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 19
- 239000000843 powder Substances 0.000 description 16
- 239000007787 solid Substances 0.000 description 16
- 239000000706 filtrate Substances 0.000 description 14
- 239000007789 gas Substances 0.000 description 14
- 238000003860 storage Methods 0.000 description 13
- GOUHYARYYWKXHS-UHFFFAOYSA-N 4-formylbenzoic acid Chemical compound OC(=O)C1=CC=C(C=O)C=C1 GOUHYARYYWKXHS-UHFFFAOYSA-N 0.000 description 12
- 238000011084 recovery Methods 0.000 description 10
- 238000011010 flushing procedure Methods 0.000 description 9
- 239000003054 catalyst Substances 0.000 description 8
- 238000001035 drying Methods 0.000 description 8
- VCZNNAKNUVJVGX-UHFFFAOYSA-N 4-methylbenzonitrile Chemical compound CC1=CC=C(C#N)C=C1 VCZNNAKNUVJVGX-UHFFFAOYSA-N 0.000 description 7
- 238000009835 boiling Methods 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 238000007599 discharging Methods 0.000 description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 238000009833 condensation Methods 0.000 description 5
- 230000005494 condensation Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 4
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 238000010981 drying operation Methods 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 229910001385 heavy metal Inorganic materials 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000012716 precipitator Substances 0.000 description 4
- 238000000746 purification Methods 0.000 description 4
- 239000012429 reaction media Substances 0.000 description 4
- 238000011144 upstream manufacturing Methods 0.000 description 4
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 239000006227 byproduct Substances 0.000 description 3
- 239000007810 chemical reaction solvent Substances 0.000 description 3
- 238000000605 extraction Methods 0.000 description 3
- 239000004615 ingredient Substances 0.000 description 3
- 238000002386 leaching Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 230000004044 response Effects 0.000 description 3
- KUCOHFSKRZZVRO-UHFFFAOYSA-N terephthalaldehyde Chemical compound O=CC1=CC=C(C=O)C=C1 KUCOHFSKRZZVRO-UHFFFAOYSA-N 0.000 description 3
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 2
- CPELXLSAUQHCOX-UHFFFAOYSA-N Hydrogen bromide Chemical compound Br CPELXLSAUQHCOX-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000013543 active substance Substances 0.000 description 2
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 2
- 229910052794 bromium Inorganic materials 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000004821 distillation Methods 0.000 description 2
- 235000021463 dry cake Nutrition 0.000 description 2
- 239000008187 granular material Substances 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 239000000543 intermediate Substances 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 238000010977 unit operation Methods 0.000 description 2
- 239000002912 waste gas Substances 0.000 description 2
- AFPHTEQTJZKQAQ-UHFFFAOYSA-N 3-nitrobenzoic acid Chemical compound OC(=O)C1=CC=CC([N+]([O-])=O)=C1 AFPHTEQTJZKQAQ-UHFFFAOYSA-N 0.000 description 1
- DKPFZGUDAPQIHT-UHFFFAOYSA-N Butyl acetate Natural products CCCCOC(C)=O DKPFZGUDAPQIHT-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 150000001242 acetic acid derivatives Chemical class 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229940043232 butyl acetate Drugs 0.000 description 1
- 239000007806 chemical reaction intermediate Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 150000001869 cobalt compounds Chemical class 0.000 description 1
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 description 1
- 238000002288 cocrystallisation Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 229940093499 ethyl acetate Drugs 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000007701 flash-distillation Methods 0.000 description 1
- FUZZWVXGSFPDMH-UHFFFAOYSA-N hexanoic acid Chemical compound CCCCCC(O)=O FUZZWVXGSFPDMH-UHFFFAOYSA-N 0.000 description 1
- 238000011086 high cleaning Methods 0.000 description 1
- 229910000042 hydrogen bromide Inorganic materials 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 229940071125 manganese acetate Drugs 0.000 description 1
- UOGMEBQRZBEZQT-UHFFFAOYSA-L manganese(2+);diacetate Chemical compound [Mn+2].CC([O-])=O.CC([O-])=O UOGMEBQRZBEZQT-UHFFFAOYSA-L 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- YKYONYBAUNKHLG-UHFFFAOYSA-N n-Propyl acetate Natural products CCCOC(C)=O YKYONYBAUNKHLG-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 229940090181 propyl acetate Drugs 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000013557 residual solvent Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- NQPDZGIKBAWPEJ-UHFFFAOYSA-N valeric acid Chemical compound CCCCC(O)=O NQPDZGIKBAWPEJ-UHFFFAOYSA-N 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
Images
Abstract
A process for producing a high-purity aromatic dicarboxylic acid, e.g., terephthalic acid, through simplified steps at a high energy efficiency. The process for producing terephthalic acid as a given target compound is characterized in that a solid-liquid separation step and a cleaning step are conducted in one apparatus and that in the step of removing a residual liquid adherent to a terephthalic acid cake by evaporation, at least part of the evaporation of the residual liquid is conducted by means of the internal energy possessed by the terephthalic acid cake and/or residual liquid.
Description
The application is based on dividing an application of following Chinese patent application:
The original bill applying date: on November 14th, 2003
Original bill application number: 200380102589.6 (PCT/JP2003/014550)
Original bill application title: the preparation method of terephthalic acid
Technical field
The present invention relates to especially method of terephthalic acid of a kind of preparation aromatic dicarboxylic acid, in particular, the present invention relates to method by heating and a kind of compound of pressurization preparation, wherein, separate and washing step can carry out with single common equipment, and comprise and to remove the reaction medium that is attached on the gained filter cake and/or the step of washings in the utilization.
Background technology
Typically, the paste mixture of terephthalic acid and reaction mother liquor through separate and the exsiccant unit operation after, terephthalic acid can obtain with the form of solid granulates.
People repeatedly attempted improving whole flow process by improving described unit operation in the past.For example, have much about the isolating technology (disclosed) of selecting of solid-liquid as patent documentation 1.Especially, not only possess separation function, but also possess very high cleaning capacity as flat rubber belting formula strainer, rotary vacuum filter, screening centrifuge decanter equipment such as (screening separating centrifuges).By using these equipment, can reclaim the mother liquor that contains a large amount of impurity that obtains being separated from each other, the filtrate and the filter cake of the low washing of foreign matter content through washing.But these filter cakes still contain useful liquid.In order to reclaim such liquid, further need carry out drying or such liquid extraction is come out with solvent.May need special equipment with its separation (disclosed) as patent documentation 2.
The exsiccant example comprises with hot gas and carries out drying as the warm air of being carried by compressed air delivery type moisture eliminator (disclosed as patent documentation 3) by indirect heating.Also known (disclosed) by evaporation liquid in the slurries in heating tube with the method that obtains solid and gas as patent documentation 4 and 5 by the people.Because these drying operationes all are isolating independently operations, must increase heat newly with dry cake.In order to reach this purpose, need extra energy and extra drying plant.
Before solid-liquid separated, common operation was to keep its suspended state with crystallization when reducing slurry temperature.For example, knownly come cool slurry so that terephthaldehyde's Acid precipitation (disclosed) as patent documentation 6 by evaporating solvent.But evaporation itself can only improve the concentration of slurries slightly, only plays the effect that reduces temperature during the course.
Obtain slurries once more and its flushing (disclosed as patent documentation 7) is also known by people by terephthalic acid and washings are mixed.Yet must after forming slurries, extract powder as everyone knows, extract powder under the pressure because be difficult in, a unfavorable factor of flushing, as, energy consumption is not taken into account.Therefore, disclosed as patent documentation 6 and 7, reduce the technology of slurry temperature and slurries reheat in drying step by consumed energy and can not say so energy-conservation.
People further know to be needed to separate filter cake under pressure.But this does not show heat energy residual before separated slurry yet effectively (seeing patent documentation 8 and 9) when dry cake.
(patent documentation 1: international monopoly PCT 93/24440; Patent documentation 2: Japanese patent gazette 60-506461; Patent documentation 3: Japanese patent gazette 52-59177; Patent documentation 4:58-11418; Patent documentation 5: Japanese patent gazette 55-164650; Patent documentation 6: English Patent 1152575; Patent documentation 7: Japanese patent gazette 11-33532; Patent documentation 8: Japanese patent gazette 1-299618; Patent documentation 9: United States Patent (USP) 5698734)
Summary of the invention
As mentioned above, multiple trial is used to improve separation independent of each other and drying operation.But do not operate the trial that comprehensively improves as a whole about separating with drying operation.
An object of the present invention is to provide a kind of with simple technology high energy efficiency ground preparation high purity aromatic dicarboxylic acid such as method of terephthalic acid.
The present inventor seeks the whole bag of tricks in the hope of reaching this purpose, and find: be not less than under the atmospheric pressure, use single general-purpose equipment that terephthalic acid cake is simply separated and wash, and after filter cake washing, reaction medium and/or the washings that is attached on the filter cake can be removed in continue using, lower filtrate of the high mother liquor of foreign matter content, foreign matter content and the crystal that contains liquid hardly can be reclaimed respectively.Thereby, can high yield make highly purified terephthalic acid.
Preparation method according to terephthalic acid of the present invention may further comprise the steps (A)～(D), (E)～(I) or (A)～(I).In these steps, solid-liquid separates and washing step (B) and (C) and/or (G) and (I) being not less than under the atmospheric pressure, carries out with single general-purpose equipment.And in step (D) and/or (I), all remain on the terephthalic acid cake or interior liquid is all removed by evaporation.Terephthalic acid cake and/or be attached on the filter cake liquid had interior can be at least as a part that is attached to the energy of the liquid on the filter cake in order to evaporation.
(A) in based on the solvent that contains acetate, under the condition that catalyzer exists, with the step of molecular oxygen oxidation of p-xylene with the acquisition terephthalic acid.
(B) slurries that will contain terephthalic acid crystals are separated into the crude terephthalic acid filter cake and mainly contain the solid-liquid separating step of the mother liquor of acetate.
(C) clean the step of crude terephthalic acid filter cake with washings.
(D) evaporation cleans that the back is any to be remained on the crude terephthalic acid filter cake/or the step of interior liquid.
(E) by under the condition that exists at catalyzer, crude terephthalic acid is contacted with hydrogen in main aqueous solvent, thus the step of impurity in the partial reduction crude terephthalic acid at least.
(F) by reducing the pressure and temperature of reaction soln, the step of crystallization terephthalic acid in main aqueous solvent.
(G) slurries are separated into the solid liquid separating step of purified terephthalic filter cake and main aqueous mother liquor.
(H) clean the step of purified terephthalic filter cake with washings.
(I) evaporation cleans that the back is any to be remained on the purified terephthalic filter cake/or the step of interior liquid.
According to the present invention, through simple operationss such as separation and extraction, the filtrate and the highly purified terephthalic acid crystals that can obtain to have the high mother liquor of foreign matter content respectively, foreign matter content are lower.The present invention is owing to saving energy and simplifying technology thereby have industrial value.
The description of the drawings
Figure 1 shows that schema according to preferred production process of the present invention.
Embodiment
Describe the present invention now in detail.
According to the present invention, during the preparation terephthalic acid, solid-liquid separates and washing step carries out continuously with individual equipment under certain pressure, this equipment can carry out obtaining the solid-liquid separating step of terephthalic acid cake from reaction mixture, also can wash the step of terephthalic acid cake, as, with equipment such as screening separating centrifuge, rotary vacuum filter, flat rubber belting formula strainers.Then, after the washing terephthalic acid cake, filter cake washes in the low atmosphere of pressure ratio washing step pressure, thereby just can utilize terephthalic acid cake and/or the interior of liquid that be attached on the filter cake can evaporate the liquid that is attached on the filter cake.
Prepare method of terephthalic acid according to the present invention and comprise two reactions steps, i.e. oxidation step (A) and reduction reaction step (E), each step all links to each other with solid-liquid separating step and washing step.Carry out with single equipment commonly used with at least one solid-liquid separating step that links to each other and washing step in step (A) and the step (E), terephthalic acid cake prepared in these steps is washed to remove liquid attached to it.
Preferably, solid-liquid separating step that links to each other with oxidation step or reduction reaction step and washing step carry out with single equipment commonly used, and terephthalic acid cake prepared in these steps is washed the liquid that is attached on the filter cake to remove.In this manual, step (A)～(D) refers to crude terephthalic acid (CTA) preparation process sometimes, and step (E)～(H) refers to purified terephthalic (PTA) preparation process sometimes.
[step (A)]
In step (A), in based on the solvent that contains acetate, under the condition that catalyzer exists, p-Xylol is by the oxidation of molecular oxygen institute.
Terephthalic acid is an aromatic dicarboxylic acid, and according to the present invention, terephthalic acid can make with common processes.Typically, terephthalic acid can react under the condition that catalyzer exists by p-Xylol and molecular oxygen and make, and described catalyzer contains heavy metal, as cobalt, iron and manganese, preferably contains the salt and the bromine of these heavy metals.
Used reaction medium preferably mainly contains acetate.As the consumption of acetic acid solvent 2～6 times of p-Xylol consumption.Except that acetate, acetic acid solvent also can contain other component, as water.The consumption of other component should not influence reaction, for example, account for gross weight 10% or lower.
Typically, the temperature that oxidizing reaction is carried out is 130～250 degrees centigrade, and preferred 150～230 degrees centigrade, pressure is 0.2～12Mpa, preferred 0.3～7Mpa, further preferred 1～3Mpa, most preferably 1～1.5Mpa.
The reactor that is used for oxidizing reaction has no particular limits, and the form of typical reactor is the complete tempering tank of belt stirrer.Reaction is preferably carried out continuously.Reaction times (mean residence time) is 30～300min.Oxidizing reaction can be carried out in a step.But in order to increase the transformation efficiency of p-Xylol, also can increase additional reactor to carry out oxidizing reaction in additional reactor in subordinate phase, temperature of reaction is lower slightly than the temperature in the main reactor, preferred 140～190 degrees centigrade.The form of the additional reactor in the subordinate phase except form is the reactor of complete mixing grooved, can be a plug flow reactor.
Oxidizing reaction can be converted into terephthalic acid with the p-Xylol of 95wt% or more (preferred 99wt% or more), thereby makes slurries, and wherein, the xln that contains terephthalic acid is separated.The impurity of trace also may produce, and impurity typically has 4-carboxyl benzaldehyde (being also sometimes referred to as " 4-CBA ").Usually, in the prepared mixture of oxidizing reaction, the content of 4-CBA is 500～500ppm of terephthalic acid.
[step (B)]
Step (B) is the solid-liquid separating step, wherein, is separated into crude terephthalic acid filter cake and reaction mother liquor by the prepared slurries that contain terephthalic acid crystals of step (A).
Step (B) and subsequent step (C) preferably carry out with single general-purpose equipment.
And used here crude terephthalic acid refers to and does not also carry out reduction reaction to remove the filter cake of 4-CBA.Typical crude terephthalic acid contains the above 4-CBA of 500ppm that accounts for terephthalic acid.
Except the acetate as solvent, the reaction mother liquor by the solid-liquid resulting separation also contains water, heavy metal catalyst, byproduct of reaction, as paratolunitrile, 4-CBA and methyl acetate.
Separate if the screening centrifuge decanter is used to solid-liquid, it is operated under the centrifugal force of 500～2000G usually.
The solid-liquid separator is operated being not less than under the atmospheric pressure usually, preferably is not less than 0.2Mpa, further preferably is not less than 0.3Mpa; And be not higher than 22Mpa, preferably be not higher than 12Mpa, further preferably be not higher than 7Mpa, especially preferably be not higher than 1.5Mpa, most preferably be not higher than 1.2Mpa.And for more energy-efficient, solid-liquid separates preferably under the situation of the pressure of the oxidation reaction process that has kept at least a portion step (A) and carries out.
When step (A) finished, if the pressure that requires to increase in the solid-liquid separator makes it carry out step (B) under the pressure that is higher than step (A), the pressure of separator can increase with for example pump when transmitting slurries.
[step (C)]
In step (C), the crude terephthalic acid filter cake that is obtained by step (B) is not less than under the atmospheric condition at pressure, cleans with washings.As described below, step (C) and step before (B) are preferably carried out in single general-purpose equipment.
Washings has no particular limits, and can be aqueous solvent, also can be oil-based solvent.But preferably contain with as the acetate of the major constituent of oxidation solvent identical contain acetic acid solution.The acetate component preferably is not less than 90%, except acetate, and the acetate esters that vaporization heat is relatively low, all available as methyl acetate, ethyl acetate, propyl acetate or butylacetate.
Pressure in the washing step is not less than normal atmosphere usually, preferably is not less than 0.2Mpa, further preferably is not less than 0.3Mpa; And be not higher than 22Mpa, preferably be not higher than 12Mpa, further preferably be not higher than 7Mpa, especially preferably be not higher than 1.5Mpa, most preferably be not higher than 1.2Mpa.
[single general-purpose equipment]
In order to reduce according to the used number of devices of method of the present invention, step (B) and step (C) are preferably carried out in single general-purpose equipment.And by using single general-purpose equipment, solid-liquid separating step (B) can carry out under identical pressure with washing step (C).
Step (B) and the used single general-purpose equipment of step (C) can be flat rubber belting formula strainer, rotary vacuum filter or screening centrifuge decanter (screening separating centrifuge).Wherein, the screening centrifuge decanter is only.The screening centrifuge decanter is for carrying out the integration apparatus that solid-liquid separates and washs simultaneously.When reacted crude terephthalic acid filter cake passed the washing position of band strainer, washings was sprayed on the filter cake, with this washing leaching cake.After passing through strainer, washings can be separated from filter cake and be recovered.
The screening centrifuge decanter can be disclosed the sort of of WO98/18750 or WO93/24440.It is separated into solid and liquid with slurries under action of centrifugal force.Solid is placed in the washing position that is sent to the band strainer on the spiral plate.
The material and the shape of strainer have no particular limits.Such as, it can be porcelain filter, wire screen or metal diagrid.Considered erosion resistance and stop up the tendency back and select suitable a kind of.If use the metal diagrid, that will select then that a part of filter cake can pass the sort ofly stops up avoiding.When screening drew off the centrifuge decanter, all mother liquors that are attached on the filter cake all had been removed at filter cake, and therefore, the contained impurity of such filter cake seldom.
In the screening centrifuge decanter, mother liquor and washings can reclaim respectively, but may have the part washings sneaks in the mother liquor.The ability of the washing leaching cake that screening centrifuge decanter tool is very high also under high pressure is suitable for industrial application.
If use the screening centrifuge decanter, the pressure in pressure in the solid-liquid separating step (B) and the washing step (C) is basic identical.
[step (D)]
In the step (D), remain on the filter cake that makes by step (C)/or interior liquid be removed by evaporation.
Moisture eliminator used among the present invention has no particular limits,, as long as it can carry out any of drying operation described below, but be typically the possess discharge valve pressure drying device of (it abbreviates " valve " sometimes as).Discharge valve has no particular limits, as long as it can be transported to low-tension side from the high-tension side with powder.It can be successive type or batch-type.For example, it can be disclosed the sort of of WO91/09661.Except the single valve door, also available as a plurality of valves that United States Patent (USP) 5589079 is disclosed, disclosed valve or the valving of WO00/71226 or United States Patent (USP) 4127935 is also available.
In the discharge valve upstream, be equipped with filter cake reserved slit (filter cake chamber) usually.Washing and isolating filter cake are retained in the filter cake reserved slit in step (C).By opening valve, filter cake is extracted in the powder storage tanks then.The opening degree of valve is preferred controlled, so that total energy keeps a certain amount of filter cake in the filter cake reserved slit.
The working pressure of filter cake reserved slit and step (C) is basic identical.Pressure in the pressure ratio filter cake reserved slit in the powder storage tanks is low.By low pressure atmosphere is arrived in the press cake release (flushing) that adds in the filter cake reserved slit, be attached to the boiling point lowering of the liquid on the filter cake.Because the reduction of boiling point, sensible heat promptly is stored in the interior energy in terephthalic acid cake and/or attached thereon the liquid, is used to evaporate the liquid that is attached on the filter cake.Before filter cake was about to draw off from the filter cake reserved slit, the temperature of filter cake (TB) preferably was higher than the liquid boiling point (Bp) under atmospheric pressure that is attached on the filter cake.
In the discharge valve upstream, the pressure in the moisture eliminator remains on usually and is not less than normal atmosphere, preferably is not less than 0.2Mpa, further preferably is not less than 0.3Mpa; And be not higher than 22Mpa, preferably be not higher than 12Mpa, further preferably be not higher than 7Mpa, especially preferably be not higher than 1.5Mpa, most preferably be not higher than 1.2Mpa.
If the screening centrifuge decanter is used to carry out step (B) and step (C), then the pressure in step (B) and the step (C) remains on and is not less than normal atmosphere.When terephthalic acid cake was transported in the filter cake reserved slit, terephthalic acid cake should keep their pressure in the screening centrifuge decanter in step (D).Therefore, pressure in step (B) and step (C) and the pressure in the filter cake reserved slit of step (D) (being the pressure of valve upstream) all should be not less than normal atmosphere, preferably are not less than 0.2Mpa, further preferably are not less than 0.3Mpa; And be not higher than 22Mpa, preferably be not higher than 12Mpa, further preferably be not higher than 7Mpa, especially preferably be not higher than 1.5Mpa, most preferably be not higher than 1.2Mpa.If the pressure gap between the pressure in barometric point and the above steps is too small, then in when flushing, it is not enough that the release of interior energy is tending towards, and therefore is difficult to the liquid on the filter cake of being attached to of evaporation q.s.If pressure is too big, then must increase the withstand voltage properties of various device and parts, this can improve the expense of whole plant.
Before being about to discharging, the temperature of filter cake need remain on 50～350 degrees centigrade, and preferred 100～300 degrees centigrade, further preferred 130～250 degrees centigrade.Be attached to liquid boiling point Bp and preferred 5～200 degrees centigrade of the difference (being that TB deducts Bp) between the temperature T B of filter cake before being about to discharging under atmospheric pressure on the filter cake, further preferred 10～150 degrees centigrade, preferred especially 15～100 degrees centigrade.
The internal pressure of powder storage tanks preferably keeps 1 normal atmosphere, but in the flushing process, the gas that is produced when being attached to the liquid evaporation on the filter cake can increase to the pressure of powder storage tanks a little higher than normal atmosphere, and this gas can be discharged from.In the case, the pressure of powder storage tanks can be brought down below normal atmosphere.
The steam that part steps (D) produces can be recovered and recycle in the step of preparation terephthalic acid.The steam that step (D) produces comprises that mainly filter cake when washing with washings, remains in the steam of the washings on the filter cake.If use in the step (C) acetate as washings, its steam then, promptly acetic acid vapor can be by easily as the solvent of the oxidizing reaction of step (A).This steam is the reactor of supplying step (A) directly, and perhaps before the supply response device, it can be condensed in heat exchanger to reclaim its heat energy.
And the crystal that contains terephthalic acid that at least a portion is carried secretly in the steam that step (D) produces can be recovered and resupply the step of preparation terephthalic acid.When in step (D), utilize to be stored in filter cake and/or to be attached to interior in the liquid on the filter cake can wash the crude terephthalic acid filter cake and be attached to liquid on the filter cake time with evaporation, the pressure of system can sharply descend in a short period of time.This crystal that may cause containing terephthalic acid is entrained in the steam of the liquid evaporation generation that is attached on the filter cake.In order to improve the productive rate of terephthalic acid, the terephthalic acid crystals that this steam is carried secretly preferably is recovered.The crystal that reclaims can resupply CTA or PTA preparation process.But because the resulting crystal of step (D) has experienced oxidizing reaction, if only by reclaiming terephthalic acid crystals, the preferred supplying step of this crystal (E) as bag filter.More preferably, the terephthalic acid crystals of carrying secretly in the steam that step (D) produces contacts with the solution that mainly contains acetate to make slurries, direct or indirect supplying step of the slurries that obtain thus (A) and/or step (B).
[step (E)]
In step (E), the crude terephthalic acid that is made by step (D) is dissolved in the main aqueous solvent, contacts at least a portion impurity of removing in the crude terephthalic acid filter cake with hydrogen by CTA under the condition that catalyzer exists.
When carrying out reduction reaction, solubleness is lower at normal temperatures owing to crude terephthalic acid, must be to its heating so that its be dissolved in the main aqueous solvent.Reduction reaction is carried out under 230～330 degrees centigrade usually, preferred 250～310 degrees centigrade.Reduction reaction also must be carried out under the pressure that is higher than the solvent vapour pressure to keep solvent to be in liquid state.Reduction reaction is carried out between 3～12Mpa usually, preferred 5～10Mpa.
In step (E), the 4-CBA that is included in the crude terephthalic acid is reduced into paratolunitrile.
[step (F)]
In step (F), the pressure and temperature of the reaction soln that is obtained by step (E) is lowered so that terephthalic acid crystallization in main aqueous solvent.
Crystallization can be carried out continuously or intermittently carry out.Typically, crystallization is carried out continuously, and pressure reduces by 2～6 times, preferred 3～5 times in the mode that progressively reduces simultaneously.In crystallisation process, because the flash distillation of solvent, the temperature of system reduces.Because the solubleness of paratolunitrile in water that 4-CBA reduction obtains is than terephthalic acid height, the terephthalic acid preferential precipitation.If but pressure is reduced to normal atmosphere, temperature will be reduced to about 100 degrees centigrade, cause paratolunitrile and terephthalic acid cocrystallization thus.Therefore, final crystallization pressure preferably is not less than 0.2Mpa, further preferably is not less than 0.3Mpa, especially preferably is not less than 0.5Mpa.Its upper limit preferably is not higher than 3Mpa, further preferably is not higher than 1Mpa, especially preferably is not higher than 0.7Mpa.The steam that produces in the crystallisation process can reclaim also recycle in the step of preparation terephthalic acid.
[step (G)]
Step (G) is the solid-liquid separating step, and wherein, the slurries that contain terephthalic acid crystals that made by step (F) are separated into purified terephthalic filter cake and main aqueous reaction mother liquor.
Here used " purified terephthalic " refers to the terephthalic acid that 4-CBA was wherein carried out reduction reaction.Contained 4-CBA is not higher than the 30ppm of terephthalic acid in the common purified terephthalic.
The solid-liquid separating step carries out with the mode identical with step (B), identical pressure basically.But in step (G), the upper limit of pressure range especially preferably is not higher than 1Mpa, most preferably is not higher than 0.7Mpa.
Except that the water as solvent, the reaction mother liquor of solid-liquid resulting separation also contains the paratolunitrile that the acetate, heavy metal catalyst, byproduct of reaction 4-CBA, the 4-CBA that sneak in a spot of oxidizing reaction formerly obtain through reduction, or the like.
[step (H)]
In step (H), the purified terephthalic filter cake that is obtained by step (G) washs with washings, and except washings was mainly moisture, this step was identical with step (C).
[single general-purpose equipment]
Step (G) and step (H) are preferably carried out in single general-purpose equipment, and it can be used the sort of in the step (C).
A kind of as in these equipment, the screening centrifuge decanter is the integration apparatus that a kind of solid-liquid lock out operation and washing operation all can carry out.When the purified terephthalic filter cake that obtains when reaction passed the washing position of band strainer, washings was sprayed on the filter cake, with this washing leaching cake.After passing through strainer, washings can be separated from filter cake and be recovered.But the part washings may be sneaked in the mother liquor.
Washings has no particular limits, and can be that aqueous solvent also can be an oil-based solvent.But preferably as mother liquor, contain the liquid of water as its major constituent.Can wash with washings and remove owing to be attached to mother liquor on the filter cake, when filter cake was discharged out from the screening centrifuge decanter, the foreign matter content of filter cake had reduced.But the part washings can be attached on the filter cake.
[step (I)]
In step (I), all are attached on the purified terephthalic/or interior liquid all be removed by evaporation, except purified terephthalic replaces crude terephthalic acid is dried, step (I) is identical with step (D).
[practical place of the present invention]
The invention is characterized in: the crystal that can reclaim mother liquor, filtrate respectively and have small amount of liquid attached to it by simple operationss such as separation, washing and extractions.Because crystal can reclaim with small amount of liquid attached to it, therefore the volume that this just may omit independent moisture eliminator or reduce moisture eliminator can save energy.Mother liquor can be reclaimed without separating with filtrate.But since mother liquor in foreign matter content than high slightly in the filtrate, they preferably are separated from each other and recycle in different steps respectively.
The separable recovery of mother liquor and filtrate has brought to whole process flow and has been highly profitable and actual advantage.Advantage is following listed.
At least a portion washings (filterable washings) that is used for washing the crude terephthalic acid filter cake can reclaim and handle the step of back recycle in the preparation terephthalic acid with it or with it.Because the foreign matter content in the filtrate is lower than in the isolated mother liquor, it can be used as the direct feed of solvent of oxidizing reaction and gives step (A).Filtrate can be used as also that absorption agent absorbs and reclaims the terephthalic acid crystals that is clipped in the solvent vapour that step (D) produces.
Reclaim the crystal that contains terephthalic acid from the filtrate that is used for washing the crude terephthalic acid filter cake to small part, and also be possible the step that the crystal that reclaims resupplies the preparation terephthalic acid.Crystal can solid-liquid separates or impel terephthaldehyde's acid crystal to reclaim through reducing temperature or pressure by filtrate is directly carried out.The isolating common method of any solid-liquid all can be in order to reach this purpose, such as centrifugal separation, filtration method or the precipitator method.The crystal that reclaims can resupply any oxidation step or hydrogen reduction step.But because therefore preferred oxidation step, particularly step (A) and/or the step (B) supplied with finished in these reactions basically.
And, reclaim at least a portion contains the acetate of separating by slurries being carried out solid-liquid separate from the crude terephthalic acid slurries mother liquor, and in the step of preparation terephthalic acid, carry out recycle with the mother liquor of recovery or with the mother liquor after its processing.For example, the oxidation solvent that such mother liquor can be used as step (A) is recycled, because it contains a lot of useful components, comprises catalyst for oxidation reaction and reaction medium.
From at least a portion mainly contains the mother liquor of the acetate of separating by slurries being carried out solid-liquid separate from the crude terephthalic acid slurries, reclaim the crystal that contains terephthalic acid, and the crystal that reclaims to be resupplied in the step of preparation terephthalic acid also be possible.Crystal can directly will separate the mother liquor that obtains through solid-liquid and carry out additional solid-liquid lock out operation, and perhaps isolated mother liquor reclaims to carry out additional solid-liquid lock out operation again after impelling crystallization and obtains through cooling or step-down at mother liquor.The additional solid-liquid lock out operation that carries out after impelling crystallization can carry out with any separation method commonly used, such as centrifugal separation, filtration method or the precipitator method.The crystal that reclaims can resupply any oxidation step or hydrogen reduction step, but preferred supplying step (A), because contain acetic acid solvent in the crystal.
The temperature and pressure and the temperature and pressure in the solid-liquid sepn process that separate the mother liquor that obtains through solid-liquid are substantially the same.Isolating mother liquor is preferably supplied with oxidation step when keeping temperature and pressure.By with high temperature mother liquor supply response device, can reduce that oxidation reaction product is heated to predetermined required energy or the sensible heat of temperature of reaction.This helps the recovery of energy in the oxidation reaction process.If but all recycles of separation mother liquor, then contained impurity tends to accumulate in system in the mother liquor, thereby reduces the quality of the terephthalic acid of solid-liquid separation gained.Therefore, Bu Fen separation mother liquor (preferred 10～30%) must be cleaned to prevent the accumulation of impurity.Mother liquor after the purification contains acetic acid solvent and is used for the catalyzer of oxidizing reaction, and derives and next organic impurity from the p-Xylol impurities in raw materials, as M-nitro benzoic acid.Keep high temperature as fruit mother liquor, the mother liquor after the purification also may contain the terephthalic acid that is contained in the separation mother liquor.Mother liquor after the purification is condensed and has high boiling component as the residual solvent of residue with evaporation.Residue contains as the cobalt compound of catalyst component and manganic compound and organic impurity.Catalyst component can reclaim in follow-up catalyst recovery and circulation step and circulate.In order to reclaim the terephthalic acid that is dissolved in the high temperature mother liquor, by evaporating solvent, mother liquor is rinsed and condensation.When mother liquor came condensation by flushing and cools off, terephthalic acid can precipitate.Throw out can separate by solid-liquid and reclaims.Reclaim the solid ingredient that obtains thus and preferably supply with oxidation step.Behind the mother liquor that separates by solid-liquid through purifying, from residual separation solution, can selectively separate and reclaim active substance such as acetate, water and catalyzer, and separation that obtains thus and recover materials can recycles in the step of preparation terephthalic acid.
And, by the purified terephthalic slurries being carried out resulting, the main aqueous separation mother liquor at least a portion of solid-liquid separation is recovered and directly or handle the back recycle in the step of preparation terephthalic acid.Separate mother liquor and can carry out solid-liquid separation, distillation or purify, and the reduction reaction solvent cycle that can be used as step (E) is utilized with film.
And, from least a portion of the mother liquor that mainly contains the water of separating from purified terephthalic, can reclaim the crystal that contains terephthalic acid.The crystal that reclaims can resupply the step of preparation terephthalic acid.Crystal preferably by condensation and/or refrigerated separation mother liquor with the precipitation terephthalic acid crystals, then mother liquor is carried out solid-liquid separation and reclaims and obtain.Solid-liquid separation can adopt any method commonly used, such as centrifugal separation, filtration method and the precipitator method.Reclaim the crystal (secondary crystal) that obtains thus and can resupply oxidation step or hydrogen reduction step.But because their intermediate content is higher, so one of them of preferred supply oxidation step, especially step (A), resulting here mother liquor (secondary mother liquid) also can be direct or indirect is recycled as the solvent of the reduction reaction of step (E).
And, at least a portion that is used to wash the washings (filtrate) of refining terephthalic acid cake can reclaim and directly or recycle after treatment in the step of preparation terephthalic acid.Because the foreign matter content of the washings that obtains that reclaims is lower, it can be used as the reduction reaction solvent of step (E) easily.The filtrate that obtains that reclaims can be distilled or purify with film.It also can be used as the terephthalic acid crystals that absorption agent is used for absorbing and recycling step (I) produces solvent vapour is carried secretly.
If be used to wash the washings of refining terephthalic acid cake contain just like, terephthalic acid by strainer, the crystal that contains terephthalic acid can be by solid-liquid separation from reclaiming to the washings of small part, and resupply the step of preparation terephthalic acid.Crystal can carry out solid-liquid separation after temperature or pressure make its crystallization and obtains by the direct solid-liquid separation of washings or through reducing.Solid-liquid separation can adopt any common method, such as centrifugal separation, filtration method and the precipitator method.The crystal that reclaims can resupply the preparation process of CTA or PTA, but since their reaction be done, so preferred supplying step (F) and/or separating step (G).
At least a portion of the steam that step (I) produces can reclaim also recycle in the step of preparation terephthalic acid.The steam that step (I) produces is mainly the washings steam that is attached on the filter cake in the washing process of step (H).Therefore, if in the step (H), water is as washings, and water vapour produces in step (I).Such water vapour can be used as the reduction reaction solvent of step (E) easily.Such steam is the reactor of supplying step (E) directly, and perhaps before the supply response device, it can be condensed in heat exchanger to reclaim its heat energy.
The crystalline at least a portion that contains terephthalic acid of carrying secretly in the steam that step (I) produces can be recovered also recycle in the step of preparation terephthalic acid.Be stored in filter cake and/or be attached to the interior energy of the liquid on the filter cake when the purified terephthalic filter cake is rinsed in step (I) with utilization, when boiling off the liquid that is attached on the filter cake, pressure in the system sharply descends in a short period of time, and this crystal that may cause containing terephthalic acid is entrained in the steam that is attached to the liquid on the filter cake.In order to improve the productive rate of terephthalic acid, the terephthalic acid crystals that this steam is carried secretly preferably reclaims.The crystal that reclaims can resupply the preparation process of CTA or PTA.But because resulting crystal has passed through reduction reaction and washing, it can be used as the finished product.Terephthalic acid crystals preferably with the form of slurries, reclaims by slurries are contacted with main aqueous solution.The slurries that obtain thus can supplying step (E)～(G).
[preferred implementation]
With reference now to Fig. 1, preferred implementation according to preparation method of the present invention is described.
Among Fig. 1, numeral 1 is the used oxidation reactor of step (A); 2 is crystallizer tank; 3 for carrying out the separator/washer of step (B) and step (C); 4 is the powder storage tanks.Between separator/washer 3 and powder storage tanks, have filter cake reserved slit and discharge valve (all not shown).Separator/washer 3 prepared crude terephthalic acid filter cakes wash into powder storage tanks 4 from the filter cake reserved slit, and the liquid that here is attached on the filter cake is evaporated.Numeral 5 is the used reduction reactor of step (E); 6 is the used crystallizer tank of step (F); 7 for carrying out the separator/washer of step (G) and step (H); 8 is moisture eliminator.Between separator/washer 7 and moisture eliminator 8, have filter cake reserved slit and discharge valve (all not shown).Separator/washer 7 prepared purified terephthalic are rinsed moisture eliminator 8 and are attached to all liquid on the filter cake with evaporation.Moisture eliminator 8 also plays the powder storage tanks simultaneously.Because the liquid that is attached on the filter cake mainly is water, simply it can not be evaporated fully, so filter cake carries out drying in moisture eliminator 8 by flushing.
The washings (mainly containing acetate) that is used for separator/washer 3 can be transported to oxidation reactor by pipeline 131 after washing.To separate with washings through the terephthalic acid of strainer if desired, then washings is transported in the solid-liquid separator 31 by pipeline 132.Isolating terephthalic acid of institute and acetate recycle on stream.
When terephthalic acid cake is washed into the powder storage tanks, be attached to part terephthalic acid that the liquid on the filter cake carries secretly and evaporate and gasify in gas.The gas that contains terephthalic acid crystals is reverted back to liquid state and is transported to solid-liquid separator 41 it be separated into terephthalic acid and mainly contain the solution of acetate.On the other hand, in solid withdrawer 42, the terephthalic acid crystals that sandwiches in gas contacts with acetate to obtain slurries, and gas is condensed.Slurries and phlegma are supplied to oxidation reactor by pipeline 101.
Be transported to solid-liquid separator from separator/washer 7 mother liquors that separate, that be used for reduction reaction by pipeline 121.In solid-liquid separator 21, terephthalic acid and the reaction intermediate that is precipitated out by condensation and/or refrigerated separation mother liquor such as paratolunitrile is separated and reclaim.Main aqueous residue reaction mother liquor goes out of use, perhaps purifies by evaporation or with film, and as the process water recycle.Contained active substance in the water can be reclaimed by ion-exchange or absorption as catalyst for oxidation reaction or paratolunitrile.
The used filtrate (solution is mainly moisture) of separator/washer 7 is transported to solid-liquid separator 51 by pipeline 151 after washing.In solid-liquid separator 51, contain the solid ingredient of the terephthalic acid that sees through from strainer and washings by separated from one another.Isolated terephthalic acid of institute and water can be distinguished recycle in flow process.In this case, solid ingredient preferably is returned in the crystallizer tank 6, and isolated washings preferably is returned in the reduction reactor 5 simultaneously.The washings itself that contains terephthalic acid also can be recovered during the course and need not pass through solid-liquid separator 51.
When terephthalic acid cake is rinsed into moisture eliminator 8, is attached to part terephthalic acid that the liquid on the filter cake carries secretly and evaporates and gasify in gas.The gas that contains terephthalic acid is condensed into liquid state and is transported to solid-liquid separator 61, and is separated into terephthalic acid and main aqueous liquid attached to it.On the other hand, in solid recovery system 62, the terephthalic acid crystals of carrying secretly in the gas contacts with water to obtain slurries, and condensation of gas becomes liquid simultaneously.Slurries and phlegma can be transported to any one of reduction reactor 5, crystallizer tank 6 or separator/washer 7.
Any one of solid- liquid separator 21,31,41,51,61 all may be equipped with clearer.By solid separated from one another and liquid, or independent solid or independent liquid all can resupply any one step of preparation terephthalic acid by pipeline 101,102,103,105,106,107,171,175,176 and/or 177.Solid may be in the same place by remix with liquid, and, when walking around solid-liquid separation step, solidliquid mixture also can directly be supplied with any one step of preparation terephthalic acid by pipeline 101,102,103,105,106,107,171,175,176 and/or 177.Its part also can go out of use.Final product is by pipeline 109 dischargings.
[embodiment]
Describe now embodiments of the invention, must be understood that by people, the present invention be not limited to for embodiment.
P-Xylol, 5 times of weight are fed in the acetate of p-Xylol and as Cobaltous diacetate, manganese acetate and the hydrogen bromide of catalyzer and can produce in the liquid-phase oxidation reactor in workshop of terephthalic acid with 39 tons speed per hour, and be 197 degrees centigrade in temperature, pressure is oxidizing reaction 90 minutes (average retention time) under the condition of 1.45Mpa.Catalyzer uses with such amount: the total content of cobalt metal is the 280ppm of weight of solvent, and the total content of manganese is the 280ppm of weight of solvent, and the total content of bromine is the 700ppm of weight of solvent.
Gas as for carry out oxidizing reaction with molecular oxygen can use air.Airborne oxygen content is 21%.Pressurized air is supplied to reactor, and the volume content of oxygen is 5% from the gas (back refers to waste gas sometimes) of reactor discharging.Then, slurries successive through oxidation is transported in the additional oxidation reactor of low temperature, and air (oxygen content: 21%) also be supplied to as oxidizing reaction gas, with at 190 degrees centigrade, 1.3Mpa condition under carry out the additional oxidizing reaction 35 minutes (average retention time) of low temperature, thereby the volume content of oxygen is 6% in the waste gas.
The slurries that made by the additional oxidizing reaction of low temperature under atmospheric pressure carry out solid-liquid separation continuously in three grades of intermediate treatment grooves, the crude terephthalic acid particle is dry in moisture eliminator as thermal source with steam.
Institute's exsiccant terephthaldehyde granulates is converted into water-soluble serous, adds hydrogen purification then in the reduction reaction atmosphere of 280 degrees centigrade and 8Mpa.Then, it is carried out continuous crystallisation.In last crystallizer tank, pressure is reduced to 0.62Mpa, and temperature is reduced to 160 degrees centigrade.
[embodiment 1]
The slurries that contain purified terephthalic that aforesaid way obtains are admitted in the incorporate screening centrifuge decanter of separator/washer in (screening separating centrifuge), and filter cake is by flush valve (discharge valve) then.Used flush valve is disclosed the sort of of WO91/09661.At the pressure that is configured in the filter cake reserved slit of valve upstream is 0.64Mpa, and the powder storage tanks that is configured in the valve downstream then is exposed under the normal atmosphere.Valve is opened a second at every turn, discharging 23kg filter cake.Slurries supply with in the screening centrifuge decanter with 4.5 tons speed per hour and washings (water) with per hour 2.0 tons of supplies.
The mother liquor that whizzer is separated contains the impurity of 900ppm, in order to wash the impurity that isolated washing filter cakes liquid then contains 240ppm.The filter cake of discharging contains the impurity of 115ppm.Their content liquid (being attached to the weight of the weight/drying back filter cake of the liquid on the filter cake) is 4.3%.
[comparative example 1]
Except not using the washings, test is carried out under the condition identical with embodiment 1.The filter cake of discharging contains the impurity of 160ppm.
[comparative example 2]
Suppose the inseparable recovery of mother liquor and washings, contained impurity is 590ppm in the recovery liquid.
[comparative example 3]
Suppose and do not use flush valve,,, infer that the content of liquid is 8.8% then according to thermal equilibrium if interiorly can be not useable for evaporating the liquid that is attached on the filter cake.
[result]
When embodiment 1 compares with comparative example 1, screen centrifuge decanter as can be seen and in washing filter cakes, play a very important role.When comparative example 1 compares with comparative example 2, by independently reclaiming washings, can utilize the low washings of foreign matter content easily as can be seen.When embodiment 1 compares with comparative example 3, by energy in using, can save a lot of energy as can be seen.These advantages are by obtaining during use screening centrifuge decanter in conjunction with interior.
[embodiment 2]
The terephthalic acid slurries that make by the low-temperature oxidation reaction are introduced directly into screening centrifuge decanter (screening separating centrifuge) when walking around crystallizer tank.Pressure in the screening centrifuge decanter remains on about 0.93Mpa.Slurries are with per hour 20 tons speed supply, and washings (acetate) is with per hour 18 tons speed supply.
In the screening centrifuge decanter,, slurries are separated into filter cake and mother liquor by solid-liquid separation.Filter cake washs with washings (acetate).The filter cake that is washed is transported to the filter cake reserved slit, and the pressure of filter cake reserved slit remains on about 0.93Mpa.In the bottom of filter cake reserved slit, the flush valve disclosed be equipped with as WO91/09661, by opening flush valve, the filter cake that is stored in the filter cake reserved slit is sent to the powder storage tanks that is exposed under the normal atmosphere.When filter cake when the filter cake reserved slit is sent to the powder storage tanks, be stored in the liquid that is attached on the filter cake and the interior heat energy that can be released and be attached to the liquid on the filter cake as evaporation in the filter cake.After the flushing, the content liquid of filter cake (being attached to the dry weight of the weight/filter cake of the liquid on the filter cake) is 0.2%.
Therefore, in the preparation process of CTA, under high pressure,, can eliminate necessary crystallizer tank and moisture eliminator in CTA preparation process up to now by separating and washing terephthalic acid slurries.This can simplify whole plant.
[embodiment 3]
In embodiment 2, the reaction mother liquor of screening in the centrifuge decanter is separated and reclaim under the pressure of 185 degrees centigrade temperature and 0.93Mpa.By purifying the reaction mother liquor of 20wt%, can be in oxidation reactor with the reaction mother liquor recycle of remainder.
That is exactly not to be depleted as the required energy of oxidizing reaction by under high pressure separating and wash the terephthalic acid slurries, can effectively use the energy that is stored in the reaction mother liquor.
[embodiment 4]
In embodiment 2, when filter cake in when flushing, the solution major part that mainly contains acetate that is attached on the filter cake is evaporated with 2 tons speed per hour.The filter cake of drying partly is entrained in the acetic acid vapor after the evaporation.Acetic acid vapor is introduced in the solid recovery system from its bottom by pipeline then, and liquid acetate is sprayed into from the top of solid recovery system, so that the acetate that sprays contacts with the terephthalic acid that sandwiches in acetic acid steam, obtains slurries thus.Resulting slurries are directly supplied with oxidation step.
Acetic acid vapor by the solid recovery system contains a spot of methyl acetate by-product.Therefore, by reclaiming acetate in the steam and methyl acetate and they being supplied with oxidation step, can reduce the loss of acetic acid solvent.
Claims (13)
1. one kind prepares method of terephthalic acid, and it comprises:
(A) in based on the solvent that contains acetate, under the condition that catalyzer exists, contain the step of the slurries of terephthalic acid crystals with acquisition with the molecular oxygen oxidation of p-xylene;
(B) be not less than under the atmospheric pressure, described slurries be separated into the crude terephthalic acid filter cake and mainly contain the solid-liquid separating step of the mother liquor of acetate;
(C) being not less than under the barometric point, clean the step of described crude terephthalic acid filter cake with washings; And
(D) evaporate and remove and clean that the back is any to be remained on the described crude terephthalic acid filter cake/or the step of interior liquid, it is characterized in that:
Described step (B) and step (C) are carried out in the individual equipment that has solid-liquid separation and washing function concurrently;
Under holding temperature and pressure and condition that temperature and pressure in the step (B) equates substantially, with the mother liquor recycle in step (A) that obtains in the step (B); And
Described terephthalic acid cake or remain on the described terephthalic acid cake/or interior liquid had interior can be used as remain in the evaporation step (D) in the described terephthalic acid cake/or at least a portion of energy of liquid.
2. preparation method of terephthalic acid as claimed in claim 1 is characterized in that, also comprises:
(E) by under the condition that exists at catalyzer, will in main aqueous solvent, contact by the crude terephthalic acid that step (D) obtains with hydrogen, thus the step of impurity in the partial reduction crude terephthalic acid at least;
(F) by reducing the pressure and temperature of reaction soln, the described terephthalic acid of crystallization is to make the step of the slurries that contain terephthalic acid crystals in main aqueous solvent;
(G) described slurries are separated into the solid-liquid separation step of purified terephthalic filter cake and main aqueous mother liquor;
(H) clean the step of described purified terephthalic filter cake with washings; And
(I) evaporate and remove and clean that the back is any to be remained on the purified terephthalic filter cake/or the step of interior liquid.
3. preparation method of terephthalic acid as claimed in claim 2 is characterized in that:
Described step (G) and step (H) are carried out being not less than under the atmospheric pressure,
Described step (G) and step (H) are carried out in the individual equipment that has solid-liquid separation and washing function concurrently.
4. as each described preparation method of terephthalic acid among the claim 1-3, wherein, described crude terephthalic acid filter cake, described mother liquor and described washings reclaim separately respectively.
5. as any one described preparation method of terephthalic acid among the claim 1-3, wherein, used washings contains acetate in the described step (C).
6. as any one described preparation method of terephthalic acid among the claim 1-3, wherein, at least a portion of the steam that produces in the described step (D) is recovered and handles the back recycle in the step of preparation terephthalic acid with it or with it.
7. preparation method of terephthalic acid as claimed in claim 6, wherein, at least a portion of the steam that produces in the described step (D) is recovered and handles the back recycle in step (A) with it or with it.
8. as any one described preparation method of terephthalic acid among the claim 1-3, wherein, the crystalline at least a portion that contains terephthalic acid of carrying secretly in the steam that produces in the described step (D) is recovered, and the crystal that is reclaimed resupplies in the step (A).
9. as claim 2 or 3 described preparation method of terephthalic acid, wherein, described purified terephthalic filter cake, described mother liquor and described washings reclaim separately respectively.
10. as claim 2 or 3 described preparation method of terephthalic acid, wherein, the described washings that uses in the described step (H) is mainly moisture.
11. as claim 2 or 3 described preparation method of terephthalic acid, wherein, at least a portion of the steam that produces in the described step (I) is recovered and handles the back recycle in described step (E) with it or with it.
12. as claim 2 or 3 described preparation method of terephthalic acid, wherein, the crystalline at least a portion that contains terephthalic acid of carrying secretly in the steam that produces in the described step (I) is recovered, and the crystal that is reclaimed resupplies to the step of preparation terephthalic acid.
13. preparation method of terephthalic acid as claimed in claim 12, wherein, the crystalline at least a portion that contains terephthalic acid of carrying secretly in the steam that produces in the described step (I) is recovered, and the crystal that is reclaimed resupplies to described step (E) and/or step (F).
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002330753 | 2002-11-14 | ||
| JP2002-330754 | 2002-11-14 | ||
| JP2002330754 | 2002-11-14 | ||
| JP2002-330753 | 2002-11-14 | ||
| JP2002330754 | 2002-11-14 | ||
| JP2002330753 | 2002-11-14 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2003801025896A Division CN100383105C (en) | 2002-11-14 | 2003-11-14 | Process for producing terephthalic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101186573A CN101186573A (en) | 2008-05-28 |
| CN101186573B true CN101186573B (en) | 2011-12-14 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2003801025896A Expired - Lifetime CN100383105C (en) | 2002-11-14 | 2003-11-14 | Process for producing terephthalic acid |
| CN 200810082532 Expired - Lifetime CN101244999B (en) | 2002-11-14 | 2003-11-14 | Process for producing terephthalic acid |
| CN2007101609799A Expired - Lifetime CN101186573B (en) | 2002-11-14 | 2003-11-14 | Process for producing terephthalic acid |
Family Applications Before (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2003801025896A Expired - Lifetime CN100383105C (en) | 2002-11-14 | 2003-11-14 | Process for producing terephthalic acid |
| CN 200810082532 Expired - Lifetime CN101244999B (en) | 2002-11-14 | 2003-11-14 | Process for producing terephthalic acid |
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| Country | Link |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7897809B2 (en) * | 2005-05-19 | 2011-03-01 | Eastman Chemical Company | Process to produce an enrichment feed |
| JP4821220B2 (en) * | 2005-09-05 | 2011-11-24 | 株式会社日立プラントテクノロジー | Continuous production method of aromatic dicarboxylic acid |
| CN101774907A (en) * | 2009-01-09 | 2010-07-14 | 谭伟业 | Unrefined phthalic acid powder delivery system and application method thereof |
| MX2011011148A (en) * | 2009-04-24 | 2012-01-27 | Invista Tech Sarl | Methods, processes, and systems for treating and purifying crude terephthalic acid and associated process streams. |
| JP2015160829A (en) * | 2014-02-27 | 2015-09-07 | 三菱化学株式会社 | Method of producing terephthalic acid |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3729284B2 (en) * | 1995-09-22 | 2005-12-21 | 三菱瓦斯化学株式会社 | Method for producing high purity terephthalic acid |
| JP3864563B2 (en) * | 1998-06-11 | 2007-01-10 | 三井化学株式会社 | Method for producing high purity terephthalic acid |
| JP2001139514A (en) * | 1999-11-16 | 2001-05-22 | Mitsubishi Chemicals Corp | Method for producing aromatic dicarboxylic acid |
-
2003
- 2003-11-14 CN CNB2003801025896A patent/CN100383105C/en not_active Expired - Lifetime
- 2003-11-14 CN CN 200810082532 patent/CN101244999B/en not_active Expired - Lifetime
- 2003-11-14 CN CN2007101609799A patent/CN101186573B/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CN101244999A (en) | 2008-08-20 |
| CN101186573A (en) | 2008-05-28 |
| CN1708472A (en) | 2005-12-14 |
| CN100383105C (en) | 2008-04-23 |
| CN101244999B (en) | 2013-03-27 |
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Address after: Within Japan Tokyo Chiyoda pill 1 chome No. 1 Co-patentee after: TOMOE ENGINEERING Co.,Ltd. Patentee after: MITSUBISHI CHEMICAL Corp. Address before: Within Japan Tokyo Chiyoda pill 1 chome No. 1 Co-patentee before: TOMOE ENGINEERING Co.,Ltd. Patentee before: MITSUBISHI RAYON Co.,Ltd. |
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