JPS61500553A - Washing water treatment method during terephthalic acid production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Effects of the invention on recovery of organic acids, catalysts, and water from the production of terephthalic acid 1) Field of invention The present invention utilizes organic acids, water, and other valuable cleaning water compositions made in the production of terephthalic acid. Concerning collection and recirculation of fractions, etc.

2) Background of the invention Industrial-grade terephthalic acid is primarily produced by liquid-phase air oxidation of P-xylene. Ra nine. A typical process includes an oxidation reactor containing solvent, air, p-xylene, A medium, etc. is continuously supplied to the reactor, and the temperature is raised to perform oxidation. Acetic acid used as total solvent It can be used as a catalyst with a type of polyvalent metal such as cobalt or manganese, or as a free catalyst. Bromine can be used as a source of radical regeneration.

The terephthalic acid remains in the form of a slurry in the reactor, which is operated at a lower temperature and pressure than the reactor. After pouring the entire slurry into a rocking vessel, the acid crystals are all centrifuged, washed, and dried. Collect.

Typical terephthalic acid deficiency process consisting of liquid phase air oxidation of P-xylene is Kirk-Othemer's Encyclopedia of Chemical Technology (Enc. cyclopedia of Chemical Technology) Volume 17 ( (1982), p. 749. Other terephthalic acid production operations are similar. It consists of a process and a reactant.

When cleaning terephthalic acid crystals, the cleaning water is amorphous terephthalic acid, P- Undesirable by-products such as terephthalic acid and benzoic acid, crystals from terephthalic acid crystals Contains all parts. Terephthalic acid manufacturing furnaces produce large amounts of such wash water. The parent has strict control over letting it out and letting it all out. Conventionally, cleaning water contains CN and other components that are harmful to the environment. allows the wash water to remain in a biological treatment cool for a long period of time, allowing microbial action to They are removed by converting them into harmless substances. However, this process is costly However, biological treatment pools require cleaning of all components contained in the cleaning water. Recirculation of the wash water is not possible.

An important point is that the above-mentioned washing water treatment system cannot recover or reuse the components in the washing water. It is. When treated in a biological treatment pool to remove those components, is destroyed by bacteria or cools to the bottom in the form of unusable sludge. accumulate.

Therefore, an improved and more sophisticated process for the treatment of wash water produced in the production of terephthalic acid is needed. needed in the industry. This improved process involves releasing the wash water into the natural water system. terephthalic acid and preferably can be recycled for reuse in the production of terephthalic acid. It is possible to remove components from the wash water so that the Desirable, this Froseth removes the useful components of the wash water so that the removed components can be reused in the production of terephthalic acid. It shall be recoverable.

In a particularly preferred embodiment, this flossing is carried out in-house and the regeneration of the components is carried out in a telefuse. Obtained by recycling materials that can be recovered and reused in the tarnic acid manufacturing process.

Is this flossing effective?) Economical and dust-free compared to traditional biological treatment pools. The need for large tracts of land shall be greatly reduced. This purpose is achieved by the present invention. Therefore, other purposes will become clear from the following explanation.

The present invention relates to the production of terephthalic acid, including terephthalic acid, metal catalysts, organic acid by-products, etc. This is the process of treating wash water.

Passing the filtrate through a cation exchange resin and the dissolved terephthalic acid and organic acid byproducts The process consists of passing the solution through an anion exchange resin to remove the . Treated water and Recovering specific components removed from wash water and reusing them in the production of terephthalic acid do. The equipment that performs the process is also described. The equipment processes a certain amount of wash water. After processing, it is recycled with similarly recovered recycled materials and used in another terephthalic acid production process. Reused.

Brief description of the drawing FIG. 1 shows the equipment and process steps of the present invention throughout the service cycle. It is a flowchart.

FIG. 2 shows the flowchart of the apparatus and process 61 of the present invention during a regeneration cycle. -This is a chart.

The apparatus for completely treating wash water from a terephthalic acid production process according to the present invention is a first It is schematically illustrated in FIG. In FIG. 1, a service cycle is shown and the second In the figure, a regeneration cycle is indicated. Wash water is used for washing terephthalic acid manufacturing operations. 1, amorphous terephthalic acid, metal catalysts, and undesirable Organic acid by-products are removed from terephthalic acid crystals.

This process is preferably used to treat wash water from the terephthalic acid production operations described above. For convenience, any water that contains the same noise as the organic acids and catalysts described here can be used. Wash water from terephthalic acid production operations may also be treated.

In the prior art, terephthalic acid is A metal catalyst is used, which is made of polyvalent metals such as cobalt and manganese. be. Organic acid a' products include P-toluic acid, benzoic acid, and other organic acid byproducts. be.

The wash water from the terephthalic acid production operation may initially be at a temperature of approximately 300'F. It's possible. As detailed below, the equipment that treats the washing water is an ion exchange tree. It is made of resin, and temperatures of 300'F can damage its resin and reduce its capacity. . Therefore, before introducing the wash water into the equipment, it is cooled to a temperature that does not cause damage. Approximately 140 Temperatures up to °F are suitable without affecting the resin, but high temperatures can also be tolerated without damage. The temperature can be increased for the fabrics that can be obtained. On the other hand, at low temperatures, water flows through the system. It is recommended that the water not be cooled below about 32°F before entering the equipment as this will inhibit the Yes.

The wash water passes through conduit 11 and filter 12 as shown in FIG.

The filtration medium 13 is selected to allow insoluble acid solids in the wash water to precipitate out. Desire Preferred filtration media are filter sand, anthracite, garnet, etc., and the particle size is similar to that of insoluble acids. The choice is made so that precipitation of solids occurs. Desirable filtration media have grain 1 of 0.3 to 1.0 Sandwich in the torso Ru. In a preferred embodiment, filter sand with a particle size of 0.4b6 or 40 mesh is used. Do? use

Ppi', the wash water is passed through the conduit 14 and the cation bed]5. bed is water It consists of a cationic resin 16 in the form of elementary ions, and can contaminate downstream ionic resins. oxidation to potential catalysts such as cobalt and manganese. When used as a product Strong acids such as Fat is desirable. Sybron Corporation on), Birmingham, N.S. (Ionac) C250, a strong acid pouring ionic resin in the form of hydrogen ions, was used in this project. Not used in the example.

Similar to terephthalic acid, P-)luyl acid and benzoic acid were dissolved in Almost all by-product 71+ is removed. For this reason, an example of a commercially desirable anionic resin Ionac, an intermediate base manufactured by Shibron Corporation, c) There is -365.

By removing the metal catalyst before passing the wash water through the anion exchange resin, The possibility of contaminating the water is reduced. In another but less desirable embodiment: In the filtration process, the insoluble acidic solids are recovered using cation-exchanged fat, but in this case The cationic resin capacity is reduced due to contamination with insoluble acids.

Option consisting of a conduit 20 and a finisher 21 for passing the wash water after removing the organic acids The finisher 21 is made of a mixed bed resin 22. mixed bed resin Which products are made of strong acid pouring ion exchange resin and strong base anion exchange resin? You can also do it. In a preferred embodiment, Ionac is used as the cationic resin. )C-249, Ionac ASB-1 was used as the anionic resin. There is.

The cleaning water treated in the above service cycle does not violate current environmental standards. , making it suitable for release into aqueous systems.

An additional benefit is that the terephthalic acid production process separates the terephthalic acid cleaning process. Recirculate the wash water for reuse. That is, the present invention Eliminate the need for a special treatment coolant and recirculate the treated cleaning water over and over again. Can be done.

Is cost a problem in terms of disposal of conventional technology? Not only can it be reduced by eliminating it, but also appropriate Also reduced by reducing or eliminating the cost of providing a full supply of pure wash water. be done.

After a certain amount of washing water has been fully treated, the regeneration cycle 'f! : Setting up PM media and ion exchange Regenerate the resin and recover the beneficial components removed from the wash water. This regeneration cycle , shown in FIG.

In the regeneration cycle, water flows back through conduit 23, filter 12, and conduit 24 to remove the filtration medium. Backwash the media so that the flow to No. 13 is the opposite of that during the service cycle. Ru. By backwashing, the insoluble acidic solids collected on the door contact are removed from the filter. The solids are recovered from the backwash water by decantation. in this way, Terephthalic acid, which was mainly lost in the waste liquid during the 70 process of conventional technology, has been removed from the manufacturing process. will be added to the total product yield.

After the decantation process, the backwash water can be disposed of or recirculated. The latter is preferable.

Regeneration of a cation exchange resin consists of removing the metal catalyst from the resin. child This is done by adding an acid to the resin that can remove metal ions from the t-S resin. This is done by making contact. Strong mineral acids such as hydrobromic acid or hydrochloric acid Regeneration acids selected from the group consisting of: Diluted hydrogen bromide for sections 2-48 Acids, especially diluted hydrobromic acid at 5-25%, are surprisingly effective in regenerating cationic resins. salt mines, etc., which can be simultaneously recycled into certain terephthalic acid manufacturing operations. After using the desired ◎- times of regeneration cycles, hydrobromic acid is directly added to the terephthalic acid product. Either recirculate it into the production operation or, before this recirculation, use the tfil for the first time in a subsequent regeneration cycle. to be reused.

Regeneration is achieved by passing regeneration acid through conduit 25, cation resin 16, and conduit 26. do. In the regeneration process, the cationic resin releases the metal catalyst and disposes of the cells. Alternatively, the latter can be recycled into other terephthalic acid production, the latter being preferred. Yes.

Regeneration of anion exchange resins removes terephthalic acid and byproducts from the resins. That's true. This is a weak acid that can remove terephthalic acid and byproducts without damaging the resin. This can be realized by first passing through the conduit 27, the anion resin 19, and the conduit 28. ice Acetic acid and formic acid are suitable for this purpose, the former forming terephthalic Vt Air oxidation of P-xylene can be recycled in manufacturing operations using acetic acid as the solvent. So, desirable. The weak acid is responsible for the dissolved P- ) Elutes luic acid, benzoic acid, and terephthalic acid. Second, coat the resin. Ammonia, sodium carbonate, aluminum, and carbon hydroxide can remove the weak acid from the resin. or an alkali such as sodium hydroxide in conduit 29, an anionic tree. The resin 19 is passed through a conduit 30 to remove weak acid attached to the resin.

In a preferred embodiment, sodium hydroxide diluted to 5-10% was used to obtain The effluent consists of acetic acid (IJ) and a significant amount of sodium hydroxide and must be disposed of. or processed for reuse.

In one embodiment, the effluent is subjected to a subsequent regeneration cycle to remove another weak acid. Reuse with.

Next to the regeneration cycle, prepare the device once again to process another wash water (C). .

Ru. Such a system is disclosed in U.S. Patent No. 4°383.920, incorporated by reference. It is described in. For improvements to these systems that meet the requirements of the present invention, This can be accomplished by a person skilled in the art. Especially when using strong acids such as hydrobromic acid in certain tanks. It is necessary that the rubber lining of the tank is unsuitable and that it has other suitable fittings. You should choose a tank.

Although the invention has been described with reference to specific implementations 15i'lI, quantitative improvements and direct substitutions It will be understood by those skilled in the art that modifications can be made without departing from the scope and spirit of the invention. It is something that can be easily understood.

M1 figure Figure 2 international search report

Claims (27)

[Claims] 1. Dissolved terephthalic acid, metal catalyst, dissolved organic acid from terephthalic acid production In the process of treating wash water containing by-products, etc., the wash water is treated with the metal catalyst. The first step is to pass the terephthalic acid through a cation exchange resin to remove the terephthalic acid and the a second step of passing said wash water through an anion exchange resin to remove products; A cleaning water treatment process characterized by: 2. The above wash water contains insoluble terephthalic acid solids and insoluble solids or organic The process further includes an acid by-product, and the process includes filtering the wash water before the first step. further comprising the step of: wherein the solid content accumulates in the filter media; Scope of Requirement The process described in item 1. 3. further comprising the step of passing the washing water through the mixed bed resin after the second step. Process according to claim 1, characterized in that: 4. The organic acid by-product is characterized by consisting of P-toluic acid and benzoic acid. A process as claimed in claim 1, wherein the process comprises: 5. Said catalyst is from the group consisting of cobalt, manganese or mixtures thereof. Process according to claim 1, characterized in that the method is selected. 6. The above anionic resin is a group consisting of weakly basic and intermediately basic anionic resins. 2. Process according to claim 1, characterized in that the process comprises: 7. Claims characterized in that the cationic resin is a strongly acidic cationic resin. The process described in box 1. 8. After the second step, recirculating the washing water to the terephthalic acid production. A process according to claim 1, further comprising: 9. Removing the metal catalyst from the above cationic resin after treating a certain amount of wash water. The claimed invention further comprises a step of regenerating the cationic resin. The process described in scope item 1. 10. The above regeneration process is carried out from the cation resin without damaging the cation resin. consisting of a step of bringing the cationic resin into contact with an acid capable of removing the metal catalyst; 10. Process according to claim 9, characterized in that: 11. The plastic according to claim 10, characterized in that the acid is a strong mineral acid. Roces. 12. The acid is hydrobromic acid, and the process includes one cycle of the regeneration step. After the above, the method further includes a step of recycling the hydrobromic acid to the production of terephthalic acid. 12. Process according to claim 11, characterized in that: 13. After the regeneration step, the metal catalyst is recycled to the terephthalic acid production. 10. The process of claim 9, further comprising the step of: 14. The terephthalic acid is extracted from the anionic resin after treating a certain amount of washing water. and further comprising a step of regenerating anions by removing by-products. Process according to claim 1, characterized in that: 15. The regeneration process removes the resin from the resin without damaging the anionic resin. A step in which the anionic resin is brought into contact with an acid capable of removing phthalic acid and byproducts. 15. Process according to claim 14, characterized in that it consists of: 16. The above acid is a weak acid selected from the group consisting of glacial acetic acid and formic acid; The process involves contacting the above anion with the above weak acid, and then adding a weak acid to the anion resin. Process according to claim 15, characterized in that it comprises a step of removing acid. vinegar. 17. The above acid is glacial acetic acid, and the above process uses the above terephthalate after the above regeneration step. The claimed invention further comprises the step of recycling said glacial acetic acid to the acid production. The process according to scope item 15. 18. Aluminum that can remove the weak acid from the anion resin without damaging the anion resin. The method further includes a step of removing the acid by bringing the anionic resin into contact with potash. 16. Process according to claim 15, characterized in that: 19. The above alkalis include ammonia, sodium carbonate, potassium hydroxide, hydroxide Claim 18, characterized in that it is selected from the group consisting of sodium. The process described in section. 20. To remove undissolved acid solids that have accumulated in the filtration media, Claim 2, further comprising the step of applying flow washing. process. 21. Particularly, the production of the above terephthalic acid consists of liquid phase air oxidation of P-xylene. A process as claimed in claim 1, characterized in that it is characterized by: 22. Dissolved and insoluble terephthalic acid from terephthalic acid production and a metal catalyst; In the filtration process that treats wash water containing dissolved and insoluble organic acid by-products, The wash water is used to remove the metal catalyst, the insoluble terephthalic acid, and the insoluble organic acid byproduct. The first step is passing through a cation exchange resin for removal, and the above-mentioned dissolved terephthalic acid and and passing the wash water through an anion exchange resin to remove the dissolved organic acid by-products. A washing water treatment process comprising a second step. 23. A first bed made of the above cationic resin and a second bed made of the above anionic resin. bed, and the washing water passes through the first bed and then through the second bed. The method according to claim 1, characterized in that it is constituted by a connecting conduit having a Treatment equipment for cleaning water produced by phthalic acid production. 24. The washing water is filtered through the filtration medium before passing through the first bed. The wash water further contains insoluble terephthalic acid solids and organic acid byproducts. The process involves filtering the wash water to remove the solids. 24. The device according to claim 23, further comprising the step of: . 25. A regeneration acid is passed through the cation bed to regenerate the cation resin. 24. The device according to claim 23, further comprising a conduit for Place. 26. In order to regenerate the anionic resin, add a weak acid and alkali to the anionic resin. Claim 23, further comprising a conduit for passing the equipment. 27. In order to remove the solid content, a pipe is added that leads the backwash water to the filter. 25. A device according to claim 24, characterized in that it comprises: