阅读说明：本技术 一种针对含苯甲酸及其酸根、和/或苯二甲酸及其酸根的混合溶液的处理工艺 (Treatment process for mixed solution containing benzoic acid and acid radical thereof and/or phthalic acid and acid radical thereof ) 是由 李玉宽 于 2019-09-18 设计创作，主要内容包括：本发明提供一种针对含苯甲酸及其酸根、和/或苯二甲酸及其酸根的混合溶液的处理工艺,属于工艺混合溶液处理领域。工艺流程为：将含苯甲酸及其酸根,和/或苯二甲酸及其酸根的混合溶液经过吸附装置,混合溶液中的苯甲酸及其酸根、和/或苯二甲酸及其酸根会被提取吸附出来使得其在混合溶液中的浓度降低,一些其余的苯系物也被提取吸附出来使得其在混合溶液中的浓度降低,吸附装置吸附饱和后再进行脱附再生,将吸附的物质脱附下来,之后再用吸附装置对混合溶液再进行吸附。达到如下的效果：经过提取吸附降低了混合溶液中苯甲酸及其酸根,和/或苯二甲酸及其酸根等苯系物的含量,降低了其排放进入污水处理单元的污水处理负荷,也利于环境保护。(The invention provides a treatment process for a mixed solution containing benzoic acid and an acid radical thereof, and/or phthalic acid and an acid radical thereof, and belongs to the field of treatment of process mixed solutions. The process flow is as follows: the method comprises the following steps of enabling a mixed solution containing benzoic acid and acid radicals thereof and/or phthalic acid and acid radicals thereof to pass through an adsorption device, extracting and adsorbing the benzoic acid and the acid radicals thereof and/or the phthalic acid and the acid radicals thereof in the mixed solution to reduce the concentration of the phthalic acid and the acid radicals thereof in the mixed solution, extracting and adsorbing some other benzene series substances to reduce the concentration of the benzene series substances in the mixed solution, carrying out desorption regeneration after the adsorption of the adsorption device is saturated, desorbing adsorbed substances, and then adsorbing the mixed solution again by using the adsorption device. The following effects are achieved: the content of benzoic acid and acid radicals thereof and/or phthalic acid and acid radicals thereof and other benzene series in the mixed solution is reduced through extraction and adsorption, the sewage treatment load of the mixed solution discharged into a sewage treatment unit is reduced, and the environment protection is facilitated.)

1. A treatment process for a mixed solution containing benzoic acid and acid radicals thereof and/or phthalic acid and acid radicals thereof is characterized in that the process route is as follows: the mixed solution containing benzoic acid and acid radicals thereof, and/or phthalic acid and acid radicals thereof enters an adsorption device, the benzoic acid and acid radicals thereof, and/or phthalic acid and acid radicals thereof in the mixed solution are extracted and adsorbed out to reduce the concentration of the benzoic acid and acid radicals thereof in the mixed solution, and the benzene series substances of other types except the benzoic acid and acid radicals thereof, and/or the phthalic acid and acid radicals thereof in the mixed solution are also extracted and adsorbed out to reduce the concentration of the benzene series substances in the mixed solution; and the mixed solution is adsorbed by an adsorption device and then discharged from the adsorption device, and the adsorption device is filled with adsorption filler.

2. The treatment process according to claim 1, wherein the mixed solution containing benzoic acid and acid groups thereof, and/or phthalic acid and acid groups thereof comprises: mother liquor of an oxidation process of a terephthalic acid production device; or mother liquor extract of an oxidation process of a terephthalic acid production device; or mixed solution obtained by removing acetic acid and partial organic matters containing benzene series from mother liquor extract of an oxidation process of a terephthalic acid production device; or the mother liquor extract of the oxidation process of the terephthalic acid production device is firstly subjected to acetic acid removal or is firstly subjected to acetic acid removal and partial removal of organic matters containing benzene series, and then is added with a mixed solution obtained by dissolving alkaline substances; or the mother liquor extract of the oxidation process of the terephthalic acid production device is firstly subjected to acetic acid removal or is firstly subjected to acetic acid removal and partial removal of organic matters containing benzene series, and then alkaline substances are added and filtered to obtain a mixed solution; the mixed solution is a liquid containing benzoic acid and acid radicals thereof, and/or phthalic acid and acid radicals thereof.

3. The process according to claim 1, characterized in that said adsorbent filler is selected from the group consisting of adsorbent resins, activated carbon or molecular sieves.

4. The process according to claim 1, wherein the adsorption device is preceded by a filtration device for filtration.

5. The process according to claim 4, wherein the mixed solution is directly or after cooling, fed into a filtering device; and a heating device is added after the filtering device enters the adsorption device, and/or a heat preservation device is arranged on the pipeline before the filtering device enters the adsorption device and on the outer wall of the adsorption device.

6. The treatment process according to claim 1, wherein after the adsorption filler is saturated by adsorption, desorption regeneration is carried out by using an alkaline solution to obtain a regeneration liquid; the adsorption filler after desorption regeneration is directly used for adsorbing the mixed solution; or the adsorption filler after desorption regeneration is used for adsorbing the mixed solution after being washed by water; or the adsorption filler after desorption regeneration is used for adsorbing the mixed solution after being washed by water and acid; or the adsorption filler after desorption regeneration is used for adsorbing the mixed solution after being washed by water, acid and water; and carrying out desorption regeneration by using an alkaline solution after the adsorption of the adsorption filler is saturated.

7. The process according to claim 6, characterized in that said alkaline solution for desorption regeneration is selected from sodium hydroxide solution, potassium carbonate solution, sodium bicarbonate solution, potassium bicarbonate solution or sodium carbonate solution.

8. The process of claim 6 wherein said regeneration liquid is drained; or heating the regeneration liquid to evaporate to dryness to precipitate solid, and recovering or discarding the solid; or adding acid into the regenerated liquid to precipitate solid, then carrying out solid-liquid separation, recovering or discarding the solid obtained by solid-liquid separation, discharging the liquid obtained by solid-liquid separation, or heating and evaporating the liquid obtained by solid-liquid separation to precipitate the solid, recovering or discarding the solid, or carrying out treatment on the liquid obtained by solid-liquid separation and the mixed solution containing benzoic acid and acid radicals thereof, and/or phthalic acid and acid radicals thereof, according to the process route of claim 1.

9. The treatment process according to claim 1, wherein when insoluble matter of salts or hydroxides is formed on the surface of the adsorbent packing, the adsorbent packing is washed with an acidic solution, and the obtained washing liquid is recycled.

10. The treatment process according to claim 9, characterized in that said acidic solution for washing is selected from an acetic acid solution and/or a hydrobromic acid solution.

11. The process according to any one of claims 1 to 10, wherein a plurality of buffer tanks are provided in the process line for stable operation of the system.

Technical Field

The invention belongs to the field of treatment of process mixed solutions, and particularly relates to a treatment process for a mixed solution containing benzoic acid and acid radicals thereof and/or phthalic acid and acid radicals thereof.

Background

Terephthalic acid is an important polyester production raw material, so that the industrial application is very wide. The main process of producing terephthalic acid comprises two procedures of oxidation and refining.

The oxidation process mainly comprises the steps that p-xylene serving as a raw material reacts with oxygen in air in a reactor to generate terephthalic acid, the reaction process needs to add elements such as cobalt, manganese and bromine as catalysts, and acetic acid as a solvent. Carrying out solid-liquid separation on the product obtained after the reaction and a solution containing acetic acid, cobalt, manganese, bromine and the like, wherein the solid is crude terephthalic acid; the mother liquor of the oxidation step is a mixed solution mainly containing acetic acid, benzoic acid and acid radicals thereof, phthalic acid and acid radicals thereof, cobalt, manganese, bromine, an oxidation intermediate p-toluic acid, an oxidation intermediate p-carboxybenzaldehyde, etc., and contains mainly acetic acid in a certain proportion according to the concentration.

The refining process is to make the product of the oxidation process enter a hydrogenation reactor, make some kinds of benzene impurities in the product of the oxidation process undergo hydrogenation reaction, and then separate the product from the terephthalic acid in a solid-liquid separation mode to improve the purity of the terephthalic acid, which is called as a finished product of the refined terephthalic acid.

In the prior art, a part of the mother liquor of the oxidation process is discharged out of an oxidation mother liquor system (namely, the mother liquor extract of the oxidation process), mainly containing phthalic acid and acid radicals thereof (containing ortho, meta and para positions, which are all referred to as phthalic acid unless otherwise specified), by-product benzoic acid and acid radicals thereof, heterocyclic compounds such as oxidation intermediate p-toluic acid, oxidation intermediate p-carboxybenzaldehyde, by-product anthraquinone fluorenone and the like, acetic acid, sodium ions, metal corrosion products in the production process (for example, iron and chromium ions, wherein the concentration of the metal corrosion products is mainly iron ions, and the concentration of the chromium ions is lower than that of the iron ions), bromide ions, cobalt ions, manganese ions and the like.

In the existing process, one of the conventional methods for treating the mother liquor extract of the oxidation process in such plants is to remove acetic acid and a part of organic matters containing benzene series (such as phthalic acid and/or benzoic acid, etc., generally by adding water, the phthalic acid and benzoic acid are not easily dissolved in water, the solubility of the phthalic acid and benzoic acid is reduced by reducing the temperature of the added water, and solid-liquid separation is performed to obtain a mixed solution, the mixed solution still has a certain solubility of phthalic acid and acid radical thereof, and benzoic acid and acid radical thereof → the mixed solution is added with basic substances (generally carbonate, bicarbonate, hydroxide) → filtration → re-addition of basic substances (generally carbonate, bicarbonate, hydroxide) → filtration → discharge to a sewage treatment process, the first addition of basic substances raises the pH (about 3.0 to 7.5), and a part of metal corrosion products forms solid to be filtered and removed (such as iron, Chromium ions, wherein the concentration of metal corrosion products is mainly iron ions, and the concentration of the chromium ions is lower than that of the iron ions, namely iron ions are mainly removed in the step), and meanwhile, phthalic acid and benzoic acid can also start to dissolve; adding alkaline substance for the second time to raise pH (pH is about 7.5-14) to form solid substance of cobalt ion and manganese ion, collecting the solid substance in the filter to recover cobalt and manganese, and periodically dissolving cobalt and manganese in the filter with hydrobromic acid and then recovering the solid substance to the oxidation reaction system (namely recovering cobalt and manganese). The solubility of phthalic acid and benzoic acid is increased in the process of adding alkaline substances twice, and the phthalic acid and the benzoic acid finally enter a sewage treatment plant.

in the prior art, another treatment method of the mother liquor extract of the oxidation process in the factory is that after the acetic acid of the mother liquor of the oxidation process is removed, alkaline substances (generally carbonate, bicarbonate and hydroxide) are directly added (filtration) → filtration → then alkaline substances (generally carbonate, bicarbonate and hydroxide) are added (filtration → discharge to a sewage treatment process), the alkaline substances are added for the first time to raise the pH (about 3.0-7.5), and a part of metal corrosion products form solid substances which are filtered and removed, and meanwhile, phthalic acid and benzoic acid start to dissolve; adding alkaline substances for the second time to increase the pH (about 7.5-14) to form solid matters of cobalt ions and manganese ions, collecting the solid matters in a filter to recover the cobalt and the manganese, and finally enabling the phthalic acid and the benzoic acid to enter a sewage treatment plant in the process.

Besides the sewage containing benzoic acid and acid radicals thereof and phthalic acid and acid radicals thereof generated by the above treatment of the oxidation mother liquor extract, the other sewage of the terephthalic acid production device also contains phthalic acid and acid radicals thereof and/or benzoic acid and acid radicals thereof, and finally enters a sewage treatment plant.

Or other factories which take benzoic acid and acid radicals thereof, and/or phthalic acid and acid radicals thereof as raw materials or products or intermediate products, or mixed solutions containing benzoic acid and acid radicals thereof, and/or phthalic acid and acid radicals thereof, and finally discharged to sewage treatment plants.

the sewage discharged to the sewage plant contains phthalic acid and acid radicals thereof, and/or benzoic acid and acid radicals thereof at high concentrations, and the treatment load of the sewage plant is still large, and if a part of the sewage is extracted before entering the sewage plant, the load of the sewage plant can be greatly reduced. (for example: the total amount of benzene series discharged to a sewage plant is naturally reduced after the processes of extracting phthalic acid and acid radicals thereof and/or benzoic acid and acid radicals thereof are added in the treatment process of the prior art in the oxidation process, or the amount of the mother liquor extract in the oxidation process can be reduced by directly extracting the benzene series from the mother liquor in the oxidation process, so that the total amount of the benzene series discharged to the sewage can be reduced, the concentrations of the benzoic acid and the acid radicals thereof in the mother liquor can be reduced, and the quality of a terephthalic acid product can be improved). The benzene series refers to substances containing benzene ring structures.

Disclosure of Invention

The invention aims to extract a part of phthalic acid and acid radicals thereof and/or benzoic acid and acid radicals thereof before entering a sewage plant by treating a mixed solution containing the phthalic acid and the acid radicals thereof and/or the benzoic acid and the acid radicals thereof, so as to reduce the total amount of the phthalic acid and the acid radicals thereof and/or the benzoic acid and the acid radicals thereof entering the sewage plant for treatment and reduce the operation load of a sewage treatment system.

The mixed solution containing benzoic acid and acid radical thereof, and/or phthalic acid and acid radical thereof can enter the process flow of the invention, for example: mother liquor (substances contained mainly comprise acetic acid according to concentration) of an oxidation process of a terephthalic acid production device; or mother liquor extract (mainly containing acetic acid according to concentration) of an oxidation process of a terephthalic acid production device; or the mother liquor extract of the oxidation process of the terephthalic acid production device is subjected to acetic acid removal (such as an evaporation method) and partial benzene-containing organic matters removal (such as partial benzene-containing organic matters removal by a method of adding water, cooling to precipitate solid and then performing solid-liquid separation, wherein the solubility of benzoic acid and phthalic acid in water is reduced during water addition and cooling, and partial benzene-containing organic matters precipitate as solid) solid-liquid separation to obtain a liquid which is a mixed solution entering the treatment of the invention; or the mother liquor extract of the oxidation process of the terephthalic acid production device is firstly subjected to acetic acid removal (for example, an evaporation method) or is firstly subjected to acetic acid removal (for example, the evaporation method) and partial benzene-containing organic matters are removed (for example, a method of adding water, reducing the temperature to precipitate solids and then performing solid-liquid separation is used for removing partial benzene-containing organic matters, the solubility of the benzoic acid and the phthalic acid in the water is reduced during the water adding and temperature reduction, and partial benzene-containing organic matters are precipitated as solids), and then a liquid obtained by adding alkaline substances (carbonate, bicarbonate, hydroxide and the like) to dissolve is a mixed solution entering the treatment of the invention (the solid benzoic acid and the phthalic acid are dissolved in the alkaline solution, and the pH is increased to about 3.0-7.5, and the; or the mother liquor extract of the oxidation process of the terephthalic acid production device is firstly subjected to acetic acid removal (such as an evaporation method) or is firstly subjected to acetic acid removal (such as an evaporation method) and partial removal of organic matters containing the benzene series (such as a method of adding water, reducing the temperature to precipitate solid and then carrying out solid-liquid separation to remove partial organic matters containing the benzene series, the solubility of the benzoic acid and the phthalic acid in the water is reduced when the water is added and the temperature is reduced, partial organic matters are precipitated into solid, then alkaline substances (carbonate, bicarbonate, hydroxide and the like, the pH is about 3.0-7.5) are added and metal corrosion products are filtered, then the alkaline substances (carbonate, bicarbonate, hydroxide and the like, the pH is about 7.5-14, at the moment, cobalt and manganese ions form insoluble substances) are added and the filtered liquid is the mixed solution which is treated by the invention; the mixed solution is a liquid containing benzoic acid and acid radicals thereof, and/or phthalic acid and acid radicals thereof.

The process flow of the invention is as follows:

The process treatment route of the mixed solution containing benzoic acid and acid radicals thereof and/or phthalic acid and acid radicals thereof entering the treatment of the invention is as follows: the method comprises the steps of feeding a mixed solution containing benzoic acid and acid radicals thereof, and/or phthalic acid and acid radicals thereof into an adsorption device, wherein the benzoic acid and acid radicals thereof, and/or the phthalic acid and acid radicals thereof in the mixed solution are partially extracted and adsorbed to reduce the concentration of the benzoic acid and acid radicals thereof, and/or the phthalic acid and acid radicals thereof in the mixed solution, if the mixed solution contains benzene series (such as p-carboxybenzaldehyde, the benzene series refers to a substance containing a benzene ring structure) other than the benzoic acid and acid radicals thereof in the adsorption process, the concentration of the benzene series in the mixed solution is reduced, the mixed solution is adsorbed by the adsorption device, and then discharged from the adsorption device, wherein the adsorption device is filled with an adsorption filler.

Based on the technical scheme, preferably, the adsorption filler is selected from adsorption resin, activated carbon or a molecular sieve, and is used for extracting and adsorbing benzoic acid and acid radicals thereof and/or phthalic acid and acid radicals thereof in the mixed solution; and extracting and adsorbing the rest benzene series contained in the mixed solution. The adsorption resin is preferably benzene series adsorption resin, and the benzene series adsorption resin refers to resin with adsorption capacity for benzene series such as terephthalic acid and acid radical thereof, benzoic acid and acid radical thereof, and the like. The molecular sieve includes artificial zeolite, natural zeolite, modified zeolite, and the like.

Based on the technical scheme, preferably, a filtering device is arranged before the mixed solution enters the adsorption device for filtering, so that the situation that insoluble substances block the adsorption filler or are deposited on the adsorption filler is avoided.

Based on the technical scheme, preferably, the mixed solution directly or after being cooled enters a filtering device; and a heating device is added after the filtering device enters the adsorption device, and/or a heat preservation device is arranged on the pipeline before the filtering device enters the adsorption device and on the outer wall of the adsorption device. The cooling device is designed because if the temperature of the mixed solution is too high for lowering the temperature (e.g., mother liquor of the oxidation process); the reason for designing the heat preservation device is that if the substances contained in the mixed solution are mainly water (for example, the mixed solution is obtained by removing acetic acid and water from the mother liquor extract in the oxidation process and reducing the temperature to remove part of benzene series), the temperature reduction during the flowing process of the mixed solution is avoided (for example, the temperature of air is low, the mixed solution dissipates heat into the air through the pipe wall of the circulating pipeline and the wall of the adsorption device to cause the temperature reduction of the mixed solution), the reduction of the temperature causes the reduction of the solubility of benzoic acid and/or phthalic acid in water, and further blocks or deposits on the adsorption filler, and the heating device and/or the heat preservation device can avoid the occurrence of such problems.

Based on the above technical solution, preferably, after the adsorption filler is saturated, the adsorption filler is subjected to desorption regeneration by using an alkaline solution to obtain a regenerated solution (phthalic acid and/or benzoic acid are easily soluble in the alkaline solution, and the desorption regeneration by using the alkaline solution is to dissolve benzene series such as phthalic acid and/or benzoic acid adsorbed on the filler by using the alkaline solution, and elute (desorb) the benzene series from the adsorption filler); the adsorption filler after desorption regeneration is directly used for adsorbing the mixed solution; or the adsorption filler after desorption regeneration is washed with water and then used for adsorbing the mixed solution again; or the adsorption filler after desorption regeneration is used for adsorbing the mixed solution after being washed by water and acid (such as sulfuric acid solution, hydrochloric acid solution, hydrobromic acid solution and acetic acid solution); or the adsorption filler after desorption regeneration is washed by water, acid (such as sulfuric acid solution, hydrochloric acid solution, hydrobromic acid solution and acetic acid solution) and then used for adsorbing the mixed solution; and carrying out desorption regeneration by using an alkaline solution after the adsorption of the adsorption filler is saturated.

Based on the above technical scheme, preferably, the alkaline solution for regeneration is selected from a sodium hydroxide solution, a potassium carbonate solution, a sodium bicarbonate solution, a potassium bicarbonate solution or a sodium carbonate solution.

based on the technical scheme, preferably, the regeneration liquid is discharged; or heating the regeneration liquid to evaporate to dryness to separate out a solid; or adding acid (such as sulfuric acid, hydrochloric acid, acetic acid, hydrobromic acid and the like) into the regenerated liquid to precipitate a solid, performing solid-liquid separation (phthalic acid and/or benzoic acid is easily soluble in an alkaline solution and is not easily soluble in an acidic solution, when the regenerated liquid is adjusted to be an acidic environment, phthalic acid and/or benzoic acid can be partially precipitated, and benzoate radicals can also be converted into benzoic acid and phthalic acid to be partially precipitated under the acidic environment), recovering or discarding the solid obtained by the solid-liquid separation, discharging the liquid obtained by the solid-liquid separation, or heating and drying the liquid obtained by the solid-liquid separation to precipitate the solid to be recovered or discarded, or mixing the liquid obtained by the solid-liquid separation with the mixed solution containing benzoic acid and acid radicals thereof, and/or phthalic acid and acid radicals thereof, and then performing the route treatment of the process again.

based on the above technical solution, preferably, when insoluble substances of salts or hydroxides are formed on the surface of the adsorption filler, the adsorption filler is washed by an acid solution (mainly, if cobalt and manganese ions are contained in the mixed solution, the adsorption filler is desorbed and regenerated by the alkaline solution, and cobalt carbonate, manganese carbonate, or cobalt hydroxide and manganese hydroxide formed by the reaction of the cobalt and manganese ions and a small amount of alkaline substances used in desorption and regeneration of the residual adsorption filler can be dissolved and eluted by the acid solution.

based on the technical scheme, preferably, the acid solution for cleaning is selected from an acetic acid solution and/or a hydrobromic acid solution, and the obtained cleaning solution is recycled.

Based on the technical scheme, preferably, in order to ensure stable operation of the system, a plurality of buffer tanks are arranged on the process route.

The discharge of the invention is discharged from the process route of the invention after the treatment of the invention, and the protection of the invention is not affected no matter what specific treatment method (such as discharge to a sewage comprehensive treatment unit) is adopted after the discharge.

The solid is recycled or discarded, and the specific treatment mode adopted after the solid is recycled or discarded does not influence the protection of the content of the invention.

The different steps, units and the like designed by the invention have different and mutually independent purposes, and each step, unit and the like can be independently applied, can be selected and combined in different sequences according to actual requirements, and can only select and apply a part of the steps, units and the like, thereby being within the protection scope of the patent of the invention.

advantageous effects

The invention aims to treat the mixed solution containing benzoic acid and acid radicals thereof, and/or phthalic acid and acid radicals thereof, and extract a part of phthalic acid and acid radicals thereof, and/or benzoic acid and acid radicals thereof, and other benzene series in the mixed solution before entering a sewage plant, so that the total amount of the benzene series entering the sewage plant for treatment is reduced, the operation load of a sewage treatment system is reduced, and the environment protection is facilitated; if the mother liquor or the mother liquor extract of the oxidation process is directly treated, the content of benzoic acid in the oxidation mother liquor can be reduced besides the total amount of benzene series treated in a sewage plant, and the product quality of terephthalic acid is improved.

Drawings

FIG. 1 is a schematic process flow diagram.

Detailed Description

Description of the drawings: english symbols for the samples were tested as follows:

TA: phthalic acid and acid radicals thereof; BA: benzoic acid and acid radicals thereof; 4-CBA: p-carboxybenzaldehyde and acid radical thereof;

The adsorbent resin used in the present invention can be selected from the brands for producing such resins, such as Tulsion, Dusheng brand, in which benzene-series adsorbent resin ADS-600 is selected as the adsorbent resin in this embodiment. The activated carbon can be selected from activated carbon products, and in the embodiment, the activated carbon is 830 type granular activated carbon of carbon environmental protection engineering ltd, tianjin. The molecular sieve can be selected from molecular sieve products on the market, and the molecular sieve in the embodiment adopts Vocko KL zeolite.

The adsorption resin, the activated carbon and the molecular sieve are all within the protection scope of the invention no matter what brand and model are selected.