CN101372452A - Method for recycling terephthalic acid from color terephthalic acid residue by hydrogenation method - Google Patents
Method for recycling terephthalic acid from color terephthalic acid residue by hydrogenation method Download PDFInfo
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- CN101372452A CN101372452A CNA2008100633066A CN200810063306A CN101372452A CN 101372452 A CN101372452 A CN 101372452A CN A2008100633066 A CNA2008100633066 A CN A2008100633066A CN 200810063306 A CN200810063306 A CN 200810063306A CN 101372452 A CN101372452 A CN 101372452A
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Abstract
The invention discloses a method for recovering terephthalic acid from colored terephthalic acid residue by hydrogenation reaction. The method comprises the following steps: firstly, the colored terephthalic acid residue and water are mixed, stirred and heated for dissolution; and then catalytic hydrogenation reaction is carried out on the mixture, and then flash cooling is carried out for crystallization; finally, a white terephthalic acid product which is crystallized and separated out is recovered by solid-liquid separation. The method can effectively remove the colored impurities from the terephthalic acid residue, and the recovered terephthalic acid product has better color quality. By using the method, discharge of solid wastes generated in the production process of pure terephthalic acid can be effectively lowered, which protects the environment. In addition, the raw material consumption and production cost are lowered, and economical benefit is improved.
Description
Technical field
The present invention relates to a kind ofly from coloured terephthaldehyde's acid residue, reclaim method of terephthalic acid, especially adopt hydrogenation method from coloured terephthaldehyde's acid residue, to reclaim method of terephthalic acid.
Background technology
In pure terephthalic acid (PTA) production process, in order to control the concentration of the foreign pigment in the terephthalic acid (TA), the method that adopts usually in the industry is to extract part circulating reaction mother liquor to carry out impurity and purification processing (US4939297, CN1572765).In mother liquor removal of impurities process, though removed most foreign pigment, also can produce a certain amount of coloured terephthalic acid solid residue simultaneously, this residue part terephthalic acid (TA) product will be discarded with the form of solid residue in CTA removal of impurities process.
Impurity in coloured terephthaldehyde's acid residue can divide two classes: a class is the impurity that is easy to remove such as phenylformic acid, p-methylbenzoic acid, to carboxyl benzaldehyde, m-phthalic acid, phthalic acid, trimellitic acid etc., though the content of such impurity than higher, is easy to remove by reaction in the technology and crystallisation process; Another kind of is colored Fluorenone, anthraquinone carboxylic acids class impurity, though the concentration of such impurity very low usually (＜50ppm), extremely low concentration (＜still have a strong impact on the colourity quality of product under 1ppm).This also is a reason of constantly strengthening mother liquor removal of impurities and the coloured terephthaldehyde's acid residue of a large amount of dischargings during PTA produces.
The quantity discharged of the terephthalic acid solid residue of PTA factory is about 0.5% of PTA output, with scale is that 600,000 tons/year PTA factory is an example, the terephthalic acid solid residue quantity discharged of annual discharging reaches 3000 tons, and wherein the depleted terephthalic acid reaches more than 2000 ton.Because the discharging of a large amount of terephthalic acid solid residues can cause the serious environmental pollution, adopt incinerating method to handle in the industry usually.Though this method has solved environmental problem, also wasted a large amount of Nonrenewable resources, be necessary to improve.
Summary of the invention
The objective of the invention is to improve existing terephthalic acid solid draff processing method, propose a kind of employing hydrogenation method and from coloured terephthaldehyde's acid residue, reclaim terephthalic acid process.
The basic ideas of the inventive method are to adopt hydrogenation reaction, make the foreign pigment reaction in coloured TA residue, remove a large amount of impurity by the crystalline method then, thereby reclaim the TA product with higher quality of colour.Concrete steps are as follows:
1) coloured terephthalic acid solid residue and water are mixed, and be warmed up to 200～350 ℃ of dissolvings, the mass ratio of water and coloured terephthalic acid solid residue is 0.2～50;
2) aqueous solution that will contain residue is sent into the hydrogenator that is filled with the Pd/C catalyzer, feeds hydrogen simultaneously and reacts, and the maintenance hydrogen partial pressure is 0.01～2MPa, and temperature of reaction is 200～350 ℃;
3) the effusive high-temperature water solution of hydrogenator is sent into crystallizer, terephthaldehyde's acid crystal is separated out, simultaneously the terephthalic acid slurry that forms is carried out solid-liquid separation, the solid of recovery gets terephthalate product through washing drying.
The ultimate principle of hydrogenation decolouring is, the strong chromophoric group of foreign pigment (as Fluorenone ring or anthraquinone ring) has carried out hydrogenation reaction in the residue under the Pd/C catalyst action, is reduced into weak chromophoric group, thereby reaches the target of hydrogenation decolouring, and reaction formula is as follows:
Yellow white
Among the present invention, said coloured terephthalic acid solid residue is the industrial waste that contains a large amount of terephthalic acids, can derive from the removal of impurities process of PX oxidizing reaction mother liquor or the throw out in the PTA waste water.Coloured terephthalic acid solid residue is except that containing terephthalic acid, Fluorenone class carboxylic acid and anthraquinone class carboxylic acid foreign pigment, also contain phenylformic acid, p-methylbenzoic acid, to one or more the industrial waste in carboxyl benzaldehyde, m-phthalic acid, phthalic acid, trimellitic acid, bromo aromatic carboxylic acid, biphenyl carboxylic acids and the benzophenone carboxylic acid's derivative, also can contain acetic acid, water and Co-Mn metal catalyzer in the residue.
Among the present invention, said water and terephthaldehyde's acid residue mass ratio are 0.2～50, preferred 1～10.
Among the present invention, the hydrogenation reaction temperature is 200～350 ℃, preferred 250～300 ℃, the speed of the Pd/C catalyst hydrogenation reactor for treatment residue aqueous solution is that every kg catalyst is per hour handled 0.1～50kg residue, and favor speed is that every kg catalyst is per hour handled 1～10kg residue.
Among the present invention, said terephthaldehyde's acid crystal can adopt the multistage flash evaporation decrease temperature crystalline, preferred 2～4 grades of flash distillation decrease temperature crystallines.
The present invention is in the process that reclaims terephthalic acid, but all part recycles of the mother liquor after the solid-liquid separation, the liquid phase part that solid-liquid separation is come out is returned dissolver, is used to dissolve coloured terephthalic acid solid residue, and another part enters treatment unit for waste water.
Beneficial effect of the present invention is:
The present invention can be to the processing of decolouring of coloured terephthalic acid solid residue, efficiently removes wherein micro-foreign pigment, efficient recovery TA component wherein, and the terephthalate product of recovery has quality of colour preferably.Use the present invention not only can reduce the discharging of solid waste in the PTA production process, the protection environment can also be cut down the consumption of raw materials, and reduces production costs, and increases economic efficiency.
Description of drawings
Fig. 1 is the hydrogenator synoptic diagram that adopts in the embodiment of the invention.
Embodiment
Further specify the present invention below in conjunction with embodiment.Need to prove that method provided by the invention is not limited to processing condition and the flow process configuration that provides among the embodiment, any local improvement to these methods can not change feature of the present invention yet.
Embodiment 1
Present embodiment carries out in hydrogenator shown in Figure 1.The space is divided into two Room A, B up and down by a sintered metal filtration sheet in the reactor: decrease temperature crystalline chamber A and high-temperature digestion hydrogenation reaction chamber B.The sintered metal filtration sheet is sealingly fastened between two Room, can bear the filtration pressure difference of 1MPa, and its maximum diameter of hole is 5 μ m, holds back the above solid particulate of particle diameter 5 μ m.Reactor also is furnished with two 3mm stainless steel tubes and is connected with atmosphere with the high pressure hydrogen steel cylinder respectively, is mainly used in to feed hydrogen, excluding air, pressure filtration operation and the operation of step-down flash distillation decrease temperature crystalline; Two stainless steel tubes are furnished with needle type valve respectively.When carrying out TA residue high-temperature digestion hydroprocessing, decrease temperature crystalline chamber A is last, and high-temperature digestion hydrogenation reaction chamber B is following; When carrying out the operation of pressure filtration and step-down flash distillation decrease temperature crystalline, this installs inversion, and high-temperature digestion crystallisation chamber B is last, and the A of filtrate chamber is following.
The handled TA residue of embodiment derives from CTA mother liquor impurity removed system, mainly consist of: TA (90.15wt%), 4-CBA (4.05wt%), PT (2.44wt%), BA (1.21wt%), IPA (0.75wt%), other component is about 1.40wt%, and the chromaticity index b value of this TA residue is 17.0.
At first remove ionized water 70ml, and take by weighing 2.475g Pd/C catalyzer (wt0.1%Pd), and add rapidly in the entry, prevent that catalyzer is exposed to inactivation in the air for a long time, water and Pd/C catalyzer are added among the reaction chamber B of reactor, take by weighing the 5.003g residue simultaneously and add reaction chamber B; Sealed reactor, maintenance A goes up the placement under the B, feeds the air in high pure nitrogen, the displacement purger, feeds 1.5MPa hydrogen then; Reactor heating to 250 ℃, and kept this temperature 1 hour dissolves residue fully and carry out hydrogenation reaction under the effect of Pd/C catalyzer.Keep the placement under the A on the reactor B, regulate and control two valves, make reacted solution and Pd/C catalyzer solid-liquid separation; Reactor is slowly cooled to room temperature, and the Pd/C catalyst solid of reactor top reaction chamber, the TA solid phase prod and the aqueous solution that filtration chamber, reactor below reclaims are taken out in release respectively, are used for analytical test behind the TA solid drying.
4-CBA in the TA solid phase, PT acid concentration adopt the Agilent1100 liquid-phase chromatographic analysis, be furnished with DAD detector and quaternary pump, chromatographic column be Agilent-ZORBAK-SB-C18 (post of 150mm * 4.6mm/5um), moving phase is the ternary gradient elution of water, methyl alcohol and acetonitrile; (analysis of UV757CRT ultraviolet-visible pectrophotometer is adopted in the analysis of λ=340nm) to the 340nm absorbancy, usually get the 0.2mol/L potassium hydroxide solution that the 0.1gTA solid is dissolved in 10ml, measure the absorbancy of this solution under wavelength 340nm (λ=340nm) then.
Embodiment 2
Carry out the processing of TA residue with the mode identical with embodiment 1, handled residue is with embodiment 1.Be 0.511g at the Pd/C catalyzer that present embodiment adopted just, residue is 5.000g, deionized water 70ml.Analyze the chromaticity index that reclaims TA, the correlation analysis data results in contrast to table 1.
Embodiment 3
Carry out the processing of TA residue with the mode identical with embodiment 1, handled residue is with embodiment 1.Be 1.247g at the Pd/C catalyzer that present embodiment adopted just, residue is 5.000g, deionized water 70ml.Analyze the chromaticity index that reclaims TA, the correlation analysis data results in contrast to table 1.
Embodiment 4
Carry out the processing of TA residue with the mode identical with embodiment 1, handled residue is with embodiment 1.Be 1.786g at the Pd/C catalyzer that present embodiment adopted just, residue is 7.143g, deionized water 50ml.Analyze the chromaticity index that reclaims TA, the correlation analysis data results in contrast to table 1.
Embodiment 5
Carry out the processing of TA residue with the mode identical with embodiment 1, handled residue is with embodiment 1.Be 220 just in the temperature of reaction that present embodiment adopted, employing ℃, the Pd/C catalyzer is 1.252g, residue is 5.001g, deionized water 70ml.Analyze the chromaticity index that reclaims TA, the correlation analysis data results in contrast to table 1.
Embodiment 6
Carry out the processing of TA residue with the mode identical with embodiment 1, handled residue is with embodiment 1.Just do not adopt the Pd/C catalyzer in the present embodiment, adopt 1.246g gac replacement Pd/C catalyzer wherein, handled residue is 5.007g, and deionized water is 70ml.Analyze the chromaticity index that reclaims TA, the correlation analysis data results in contrast to table 1.
The TA product index that reclaims by residue under the different hydroconversion conditions of table 1
| Embodiment | Water/ml | Residue/g | Pd/C /g | Hydrogenation temperature/℃ | 4-CBA (wt％) | Absorbancy (λ=340nm) |
| 1 | 70 | 5.003 | 2.475 | 250 | <0.005 | 0.026 |
| 2 | 70 | 5.000 | 0.511 | 250 | <0.005 | 0.247 |
| 3 | 70 | 5.000 | 1.247 | 250 | <0.005 | 0.025 |
| 4 | 50 | 7.143 | 1.786 | 250 | <0.005 | 0.056 |
| 5 | 70 | 5.001 | 1.252 | 220 | <0.005 | 0.338 |
| 6 | 70 | 5.007 | 1.246g gac | 250 | 0.851 | 0.393 |
| The TA residue | —— | —— | —— | —— | 4.05 | 0.450 |
Comparative example 1～6 result adopts Pd/C shortening method can remove foreign pigment in the TA residue effectively as can be known, and the TA product chromaticity index of recovery is very good, and the concentration of 4-CBA also reduces significantly.
Claims (6)
1. adopt hydrogenation method from coloured terephthaldehyde's acid residue, to reclaim method of terephthalic acid, it is characterized in that step is as follows:
1) coloured terephthalic acid solid residue and water are mixed, and be warmed up to 200～350 ℃ of dissolvings, the mass ratio of water and coloured terephthalic acid solid residue is 0.2～50;
2) aqueous solution that will contain residue is sent into the hydrogenator that is filled with the Pd/C catalyzer, feeds hydrogen simultaneously and reacts, and the maintenance hydrogen partial pressure is 0.01～2MPa, and temperature of reaction is 200～350 ℃;
3) the effusive high-temperature water solution of hydrogenator is sent into crystallizer, terephthaldehyde's acid crystal is separated out, simultaneously the terephthalic acid slurry that forms is carried out solid-liquid separation, the solid of recovery gets terephthalate product through washing drying.
2. according to claim 1ly from coloured terephthaldehyde's acid residue, reclaim method of terephthalic acid, it is characterized in that said coloured terephthalic acid solid residue except that containing terephthalic acid, Fluorenone class carboxylic acid and anthraquinone class carboxylic acid foreign pigment, also contain phenylformic acid, p-methylbenzoic acid, one or more the industrial waste in carboxyl benzaldehyde, m-phthalic acid, phthalic acid, trimellitic acid, bromo aromatic carboxylic acid, biphenyl carboxylic acids and the benzophenone carboxylic acid's derivative.
3. according to claim 2ly from coloured terephthaldehyde's acid residue, reclaim method of terephthalic acid, it is characterized in that said coloured terephthalic acid solid residue also contains acetic acid, water and Co-Mn metal catalyzer.
4. according to claim 1ly reclaim method of terephthalic acid from coloured terephthaldehyde's acid residue, the quality percentage composition that it is characterized in that Pd in the said Pd/C catalyzer is 0.01～5%.
5. according to claim 1ly from coloured terephthaldehyde's acid residue, reclaim method of terephthalic acid, it is characterized in that it is that every kg catalyst is per hour handled 0.1～50kg residue that said hydrogenator is handled the speed of the residue aqueous solution.
6. according to claim 1ly reclaim method of terephthalic acid from coloured terephthaldehyde's acid residue, it is characterized in that the part of liquid phase is returned dissolver after the solid-liquid separation, another part enters treatment unit for waste water.
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| Application Number | Priority Date | Filing Date | Title |
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| CNA2008100633066A CN101372452A (en) | 2008-08-01 | 2008-08-01 | Method for recycling terephthalic acid from color terephthalic acid residue by hydrogenation method |
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| CNA2008100633066A CN101372452A (en) | 2008-08-01 | 2008-08-01 | Method for recycling terephthalic acid from color terephthalic acid residue by hydrogenation method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101914013A (en) * | 2010-07-30 | 2010-12-15 | 浙江大学 | Water-saving terephthalic acid production method |
| CN102247839A (en) * | 2010-05-17 | 2011-11-23 | 中国石油化工股份有限公司 | Smooth transition method for initial activity of palladium-carbon catalyst |
| CN103373917A (en) * | 2012-04-17 | 2013-10-30 | 博凯勒机械工程股份有限公司 | Method and equipment for producing PTA (p-terephthalic acid) |
-
2008
- 2008-08-01 CN CNA2008100633066A patent/CN101372452A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102247839A (en) * | 2010-05-17 | 2011-11-23 | 中国石油化工股份有限公司 | Smooth transition method for initial activity of palladium-carbon catalyst |
| CN101914013A (en) * | 2010-07-30 | 2010-12-15 | 浙江大学 | Water-saving terephthalic acid production method |
| CN101914013B (en) * | 2010-07-30 | 2015-03-18 | 浙江大学 | Water-saving terephthalic acid production method |
| CN103373917A (en) * | 2012-04-17 | 2013-10-30 | 博凯勒机械工程股份有限公司 | Method and equipment for producing PTA (p-terephthalic acid) |
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Application publication date: 20090225 |