Method and device for treating and resourcefully utilizing the waste water from the production of cyclopentadecanolide perfumes

Abstract

The application discloses a method and device for treating and comprehensively utilizing waste water in cyclopentadecanolide perfume production, relates to the technical field of cyclopentadecanolide perfume production, and comprises the following steps: neutralizing acetic acid waste water, waste water low-temperature vacuum evaporation, evaporated condensate water reuse, solid-liquid separation of evaporated concentrated liquid, distillation recovery of toluene from concentrated liquid for reuse, and recycling of solid crystallized sodium acetate by recrystallization. The application not only realizes standard discharge of waste water, but also realizes recycling of resources, reduces energy consumption of waste water treatment, and is not limited by the concentration of salt water.

Description

Technical Field

[0001] This invention belongs to the field of cyclopentadecanolactone fragrance production technology, specifically a method and apparatus for the comprehensive utilization of wastewater from cyclopentadecanolactone fragrance production. Background Technology

[0002] Macrocyclic lactones are molecules with more than twelve carbon atoms and at least one ester bond in their macrocyclic skeleton. Cyclopentadecanolactone, also known as amaranthin, is a very important macrocyclic musk. It possesses not only a musky aroma but also an ambergris-like fragrance, exhibiting a rich, long-lasting, delicate, and penetrating aroma. It is widely used in the formulation of perfumes, cosmetics, and food flavorings. Simultaneously, it has excellent fixative properties, leading to its widespread use in woody, oriental, fantasy, amber, and floral fragrances. It is also an important pharmaceutical synthesis intermediate used in the daily chemical and pharmaceutical industries. Cyclopentadecanolactone is an indispensable raw material in the formulation of high-grade fragrances, and therefore widely used in the formulation of shampoos, conditioners, high-end perfumes, various soaps, detergents, powders, and personal care products. Cyclopentadecanolactone can also be used as a food additive. When used in food flavorings, it can be used in combination with common macrocyclic lactones and achieve better results. Because it can improve the palatability of food, increase people's appetite, and is harmless to health, it is widely used in the flavorings of nuts, vanilla, berries, spirits, pastries, and other foods.

[0003] Because natural sources of cyclopentadecanol are relatively scarce, most commercially available cyclopentadecanol is currently obtained through chemical synthesis. Only a few countries abroad are capable of small-scale production of cyclopentadecanol, and it is extremely expensive. The synthesis of cyclopentadecanol fragrances is complex, involving numerous steps and the use of various solvents such as benzene or toluene. The production process inevitably generates wastewater with high CODcr concentrations, high salt content, high toluene content, and dark color, which is difficult to treat. Therefore, developing an environmentally friendly cyclopentadecanol production process has extremely significant economic and social benefits.

[0004] The production of cyclopentadecanol flavorings is a typical example of fine chemical production. Fine chemical wastewater is characterized by large discharge volumes, high CODcr concentrations, deep color, high toxicity, complex pollutant composition, and difficulty in biodegradation. The production process of cyclopentadecanol flavorings uses toluene as a solvent and generates wastewater containing high levels of acetic acid or acetates. The discharged wastewater mainly includes: light blue process wastewater from the hydrolysis stage of the addition esterification process, with toluene, cyclic ketones, esters, and sodium acetate as the main pollutants; reddish-brown process wastewater from the oxidation stage, with toluene, cyclic ketones, ethers, and acetic acid as the main pollutants; and dark blue process wastewater from the decomposition and neutralization stage, with toluene and sodium acetate as the main pollutants. Currently, the treatment of process wastewater with high toluene, high salt, and high CODcr concentrations from cyclopentadecanol is often achieved by dilution to reduce the salt content. However, discharging this reduced-salt wastewater not only causes environmental degradation but also leads to soil and watershed salinization. Furthermore, the organic matter in the wastewater contains benzene ring compounds, which have poor biodegradability, high biotoxicity, and pose significant environmental safety hazards, even affecting people's daily lives. Some processes use triple-effect evaporation for pretreatment followed by integrated biological and chemical treatment to treat this portion of the process wastewater. However, these conventional treatment methods cannot achieve excessively high brine concentrations and have high energy consumption and treatment costs, thus failing to meet the needs of wastewater treatment. Summary of the Invention

[0005] To address the problems mentioned in the background art, this invention proposes a method and apparatus for the comprehensive utilization of resources from wastewater treatment in the production of cyclopentadecanol flavorings.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] S1, Neutralize acetic acid wastewater: Collect acetic acid wastewater from the oxidation process in the production of cyclopentadecanol separately, add sodium hydroxide solution to neutralize acetic acid until the pH of the wastewater is 7-9, forming wastewater containing sodium acetate salts;

[0008] S2, Low-temperature vacuum evaporation: Other wastewater containing salt and high toluene content generated during the production of cyclopentadecanol and the neutralized acetic acid wastewater generated in step S1 are combined and pumped into a low-temperature vacuum evaporator. The boiling point is lowered under low vacuum conditions. Then, taking advantage of the difference in boiling points between water and other organic substances, evaporation and condensation are carried out under low-temperature conditions to separate water from other organic substances, resulting in evaporated condensate and concentrated waste liquid.

[0009] S3. Evaporation condensate reuse: Collect the evaporation condensate obtained in step S2 and replace the clean water used in the production process of cyclopentadecanol for washing and cleaning.

[0010] S4. Solid-liquid separation of evaporation concentrate: The concentrated waste liquid obtained in step S2 is transferred into a solid-liquid separation tank for separation of solid and liquid phases, and sodium acetate solid crystals containing 3 molecules of water of crystallization and organic concentrate are collected respectively.

[0011] S5. Concentrated liquid distillation and recycling: The organic concentrate collected in step S4 is transferred to a fractionating kettle, and toluene is recovered and recycled under low vacuum conditions and negative pressure. The bottom of the kettle is sent to a waste liquid incinerator for incineration.

[0012] S6. Recrystallization and reuse of sodium acetate solid crystals: The sodium acetate solid obtained in step S4 is added to ethanol for recrystallization, and solid-liquid separation is performed using a centrifuge to obtain sodium acetate and mother liquor respectively. The mother liquor is distilled to recover ethanol for reuse. Sodium acetate is reused as a raw material in the cyclopentadecanolactone addition esterification process.

[0013] As a further preferred embodiment of this technical solution: the volume fraction of the sodium hydroxide solution in step S1 is 30%.

[0014] As a further preferred embodiment of this technical solution: the vacuum condition in step S2 is 1000 Pa, and the low temperature condition is 28℃~38℃.

[0015] As a further preferred embodiment of this technical solution: in step S5, the temperature of the distillation vessel is 60℃~80℃, and the low vacuum condition is 33333Pa.

[0016] As a further preferred embodiment of this technical solution: the temperature at which ethanol is recycled in step S6 is 75℃~80℃.

[0017] As a further preferred embodiment of this technical solution: it includes a pretreatment neutralization reactor, an acid-containing wastewater high-level tank, and a 30% sodium hydroxide solution high-level tank, wherein the acid-containing wastewater high-level tank and the 30% sodium hydroxide solution high-level tank are respectively connected to the pretreatment neutralization reactor via pipelines, and the pretreatment neutralization reactor is also connected to a low-temperature vacuum evaporator via pipelines.

[0018] The low-temperature vacuum evaporator includes an evaporating tank, which is connected to a defoamer high-level tank via a pipe. The evaporating tank is also connected to a condensate receiving tank via a first condenser. The evaporating tank is also connected to a heater via a concentrate circulation pump. The evaporating tank is connected to a settling tank via a concentrate discharge pump. The settling tank is connected to a solid-liquid separation tank via a pipe.

[0019] As a further preferred embodiment of this technical solution: the low-temperature vacuum evaporator also includes a feed proportioning valve installed on the pipeline between the pretreatment neutralization vessel and the low-temperature vacuum evaporator, which is used to control the flow rate of wastewater entering the low-temperature vacuum evaporator.

[0020] As a further preferred embodiment of this technical solution: the condensate receiving tank is connected to a condensate storage tank via a pipeline, the solid-liquid separation tank is connected to a crystallization vessel via a pipeline, the crystallization vessel is connected to an ethanol high-level tank and a centrifuge via pipelines, the centrifuge is connected to a mother liquor tank via a pipeline, the mother liquor tank is connected to a flash evaporator via a pipeline, the flash evaporator is connected to an ethanol receiving tank via a second condenser, and the ethanol receiving tank is connected to the ethanol high-level tank via a pipeline.

[0021] As a further preferred embodiment of this technical solution: the settling tank and the solid-liquid separation tank are connected to a distillation vessel via a pipeline.

[0022] As a further preferred embodiment of this technical solution: the fractionation kettle is connected to a toluene vacuum receiving tank via a spiral plate heat exchanger, and the toluene vacuum receiving tank is connected to a toluene temporary storage tank via a pipeline.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. In this invention, valuable resources such as sodium acetate, toluene, and ethanol are recovered from the wastewater of cyclopentadecanol flavoring production. After recrystallization, sodium acetate is obtained as high-purity sodium acetate monohydrate, which can be directly used as a raw material for the cyclopentadecanol addition esterification process, greatly reducing production costs. At the same time, toluene and ethanol are also successfully applied to the production process through negative pressure recovery and normal pressure recovery, maximizing the utilization of resources.

[0025] 2. In this invention, the wastewater treated by this method has significantly improved effluent quality. The CODcr, toluene, and TOC contents of the evaporation condensate are all far below the relevant environmental protection standards, reaching the standard of high-quality water resources. It can be directly used in the washing and cleaning processes of cyclopentadecanol production, reducing the use of fresh water and lowering water resource consumption. In addition, unusable waste liquid is transferred to a waste liquid incinerator for incineration, ensuring that all waste is properly treated and avoiding the risk of environmental pollution. Attached Figure Description

[0026] Figure 1 A schematic diagram of a device for the comprehensive utilization of wastewater from the production of cyclopentadecanol flavoring.

[0027] Legend: 1. Pretreatment neutralization vessel; 2. High-level tank for acidic wastewater; 3. High-level tank for 30% sodium hydroxide; 4. High-level tank for defoamer; 5. Low-temperature vacuum evaporator; 5-1. Feed proportioning valve; 5-2. Evaporator; 5-3. Heater; 5-4. Concentrate circulation pump; 5-5. No. 1 condenser; 5-6. Condensate receiving tank; 5-7. Concentrate discharge pump; 5-8. Settling tank; 5-9. Solid-liquid separation tank; 6. Condensate storage tank; 7. Crystallization vessel; 8. High-level tank for ethanol; 9. Centrifuge; 10. Mother liquor tank; 11. Flash evaporator; 12. No. 2 condenser; 13. Ethanol receiving tank; 14. Fractionating vessel; 15. Spiral plate heat exchanger; 16. Toluene vacuum receiving tank; 17. Toluene temporary storage tank. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Please see Figure 1This application provides a method and apparatus for the comprehensive utilization of wastewater from the production of cyclopentadecanol flavoring, comprising a pretreatment neutralization tank 1, an acidic wastewater high-level tank 2, and a 30% sodium hydroxide solution high-level tank 3. The acidic wastewater high-level tank 2 and the 30% sodium hydroxide solution high-level tank 3 are respectively connected to the pretreatment neutralization tank 1 via pipelines. The pretreatment neutralization tank 1 is also connected to a low-temperature vacuum evaporator 5 via a pipeline. The low-temperature vacuum evaporator 5 includes an evaporator tank 5-2, which is connected to an antifoaming agent high-level tank 4 via a pipeline. The evaporator tank 5-2 is connected to a condensate receiving tank 5-6 via a first condenser 5-5. The evaporator tank 5-2 is also connected to a heater 5-3 via a concentrate circulation pump 5-4. The evaporator tank 5-2 is connected to a settling tank 5-8 via a concentrate discharge pump 5-7. The settling tank 5-8 is connected to a solid-liquid separation tank 5-9 via a pipeline. The low-temperature vacuum evaporator 5 also includes... A feed proportioning valve 5-1 is installed on the pipeline between the pretreatment neutralizing vessel 1 and the low-temperature vacuum evaporator 5 to control the flow rate of wastewater entering the low-temperature vacuum evaporator 5. The condensate receiving tank 5-6 is connected to the condensate storage tank 6 via a pipeline. The solid-liquid separation tank 5-9 is connected to the crystallization vessel 7 via a pipeline. The crystallization vessel 7 is connected to the ethanol high-level tank 8 and the centrifuge 9 via pipelines. The centrifuge 9 is connected to the mother liquor tank 10 via a pipeline. The mother liquor tank 10 is connected to the flash evaporator 11 via a pipeline. The flash evaporator 11 is connected to the ethanol receiving tank 13 via the second condenser 12, and the ethanol receiving tank 13 is connected to the ethanol high-level tank 8 via a pipeline. The settling tank 5-8 and the solid-liquid separation tank 5-9 are connected to the fractionation vessel 14 via a pipeline. The fractionation vessel 14 is connected to the toluene vacuum receiving tank 16 via a spiral plate heat exchanger 15. The toluene vacuum receiving tank 16 is connected to the toluene temporary storage tank 17 via a pipeline.

[0030] Specifically, acidic wastewater containing acetic acid from the oxidation process of the cyclopentadecanol flavoring production process is collected separately and added to the pretreatment neutralization reactor 1. Stirring is started, and 30% sodium hydroxide solution is slowly added to the pretreatment neutralization reactor 1 from the sodium hydroxide high-level tank 3. The wastewater is neutralized until the pH value is measured to be 7-9, forming organic wastewater containing sodium acetate. Then, wastewater containing salt and high toluene content from the addition and decomposition neutralization processes of the cyclopentadecanol production process is collected and transferred from the wastewater collection pool in the production workshop to the pretreatment neutralization reactor 1 using a pump. This mixture is then thoroughly mixed with the neutralized acetic acid wastewater generated above, and then pumped into the evaporator 5 of the low-temperature vacuum evaporator 5 through a feed proportioning valve and a metering pump. In step 2, defoamer is simultaneously metered from the defoamer high-level tank 4 into the evaporator 5-2 to prevent the generation of excessive foam. Evaporation and condensation are carried out under high vacuum conditions of 1000 Pa and low temperature conditions of 28~38℃. The aqueous phase is condensed in condenser 5-5 to obtain aqueous evaporation condensate. The bottom material is transferred to heater 5-3 via concentrate circulation pump 5-4 for heating and then returned to evaporator 5-2 for evaporation and concentration, resulting in concentrated organic phase waste liquid. The obtained evaporation condensate is then collected and transferred to condensate storage tank 6 via condensate receiving tank 5-6 for reuse in the washing and cleaning processes during the production of cyclopentadecanol. Finally, the obtained concentrated waste liquid is transferred to a low-temperature vacuum evaporator via concentrate discharge pump 5-7. The product undergoes initial separation in settling tanks 5-8 of the generator 5, and then is transferred to solid-liquid separation tanks 5-9 for further solid-liquid separation, yielding sodium acetate solid containing water of crystallization and concentrated organic matter solution, respectively. These are then transferred to crystallization vessel 7 and fractionation vessel 14. The collected concentrated organic matter solution is transferred to fractionation vessel 14, where the steam valve is opened to heat it to a vessel temperature of 60-80°C. Toluene is recovered under negative pressure at a low vacuum of 33333 Pa until the temperature at the top of the column drops or no product is discharged. The recovered toluene is condensed by spiral plate heat exchanger 15, then recovered through toluene vacuum receiving tank 16, and transferred to toluene temporary storage tank 17 for reuse. Afterwards, it is metered from the high-level ethanol tank 8 to the crystallization vessel. Ethanol is added to vessel 7, stirring is started, and the resulting sodium acetate solid is added to crystallization vessel 7. The jacketed steam valve is opened, and the steam in the vessel is condensed by the condenser and returned to crystallization vessel 7. Then, the cooling water valve is opened to cool down and precipitate crystals. The mother liquor tank 10 is evacuated, and the recrystallized solid-liquid mixture is transferred to centrifuge 9. Centrifuge 9 is started for solid-liquid separation. Finally, the mother liquor separated from the solid-liquid mixture is transferred to flash evaporator 11 through mother liquor tank 10. Ethanol is recovered and reused at atmospheric pressure under conditions of 75~80℃. After the ethanol is condensed by condenser 12, it is transferred to ethanol high-level tank 8 through ethanol receiving tank 13 for reuse. The solid crystals remain in centrifuge 9 to obtain sodium acetate, which is used as raw material for the cyclopentadecanol addition ester process for reuse.

[0031] In summary, through physical and chemical methods for fractional extraction, the evaporation condensate collected from the effluent was tested and found to have a CODcr content of 20.3 mg / L, a toluene content of 0.15 mg / L, and a TOC content of 5-10 mg / L. The sodium acetate obtained by recrystallization was tested and found to contain one unit of water of crystallization, with a sodium acetate monohydrate content of 98.1%. This not only achieved the standard discharge of wastewater but also enabled resource recycling, reduced energy consumption in wastewater treatment, and was not limited by the concentration of brine.

[0032] The above embodiments are only used to illustrate the technical methods of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of the present invention without departing from the spirit and scope of the technical methods of the present invention.

Claims

1. A method for the comprehensive utilization of resources from wastewater generated during the production of cyclopentadecanol flavorings, characterized in that, Specifically, the following steps are included: S1, Neutralize acetic acid wastewater: Collect acetic acid wastewater from the oxidation process in the production of cyclopentadecanol separately, add sodium hydroxide solution to neutralize acetic acid until the pH of the wastewater is 7-9, forming wastewater containing sodium acetate salts; S2, Low-temperature vacuum evaporation: Other wastewater containing salt and high toluene content generated during the production of cyclopentadecanol and the neutralized acetic acid wastewater generated in step S1 are combined and pumped into the low-temperature vacuum evaporator (5). The boiling point is lowered under low vacuum conditions. Then, taking advantage of the difference in boiling points between water and other organic substances, evaporation and condensation are carried out under low-temperature conditions to separate water from other organic substances and obtain evaporated condensate and concentrated waste liquid. S3. Evaporation condensate reuse: Collect the evaporation condensate obtained in step S2 and replace the clean water used in the production process of cyclopentadecanol for washing and cleaning. S4. Solid-liquid separation of evaporation concentrate: The concentrated waste liquid obtained in step S2 is transferred into a solid-liquid separation tank (5-9) for separation of solid and liquid phases, and sodium acetate solid crystals containing 3 molecules of water of crystallization and organic concentrate are collected respectively. S5. Concentrated liquid distillation and recycling: The organic concentrate collected in step S4 is transferred to a fractionating kettle (14). Under low vacuum conditions, toluene is recycled under negative pressure. The bottom of the kettle is sent to a waste liquid incinerator for incineration. S6. Recrystallization and reuse of sodium acetate solid crystals: The sodium acetate solid obtained in step S4 is added to ethanol for recrystallization, and solid-liquid separation is performed using a centrifuge (9) to obtain sodium acetate and mother liquor respectively. The mother liquor is distilled to recover ethanol for reuse. Sodium acetate is reused as a raw material for the cyclopentadecanolactone addition ester process.

2. The method for comprehensive utilization of resources in the treatment of wastewater from the production of cyclopentadecanol flavorings according to claim 1, characterized in that, The sodium hydroxide solution in step S1 has a volume fraction of 30%.

3. The method for comprehensive utilization of resources in the treatment of wastewater from the production of cyclopentadecanol flavorings according to claim 2, characterized in that, In step S2, the vacuum condition is 1000 Pa and the low temperature condition is 28℃~38℃.

4. The method for comprehensive utilization of resources in the treatment of wastewater from the production of cyclopentadecanol flavoring according to claim 3, characterized in that, In step S5, the temperature of the fractionation vessel (14) is 60℃~80℃, and the low vacuum condition is 33333Pa.

5. The method for comprehensive utilization of resources in the treatment of wastewater from the production of cyclopentadecanol flavorings according to claim 4, characterized in that, The temperature at which ethanol is recycled in step S6 is 75℃~80℃.

6. The method for comprehensive utilization of resources in the treatment of wastewater from the production of cyclopentadecanol flavorings according to claim 5, characterized in that, The device for the comprehensive utilization of wastewater from the production of cyclopentadecanol flavoring includes a pretreatment neutralization tank (1), an acidic wastewater high-level tank (2), and a 30% sodium hydroxide solution high-level tank (3). The acidic wastewater high-level tank (2) and the 30% sodium hydroxide solution high-level tank (3) are respectively connected to the pretreatment neutralization tank (1) through pipelines. The pretreatment neutralization tank (1) is also connected to a low-temperature vacuum evaporator (5) through a pipeline. The low-temperature vacuum evaporator (5) includes an evaporator (5-2), which is connected to a defoamer high-level tank (4) via a pipe. The evaporator (5-2) is connected to a condensate receiving tank (5-6) via a first condenser (5-5). The evaporator (5-2) is also connected to a heater (5-3) via a concentrate circulation pump (5-4). The evaporator (5-2) is connected to a settling tank (5-8) via a concentrate discharge pump (5-7). The settling tank (5-8) is connected to a solid-liquid separation tank (5-9) via a pipe.

7. The method for comprehensive utilization of resources in the treatment of wastewater from the production of cyclopentadecanol flavorings according to claim 6, characterized in that, The low-temperature vacuum evaporator (5) also includes a feed proportioning valve (5-1) installed on the pipeline between the pretreatment neutralizing vessel (1) and the low-temperature vacuum evaporator (5) for controlling the flow rate of wastewater entering the low-temperature vacuum evaporator (5).

8. The method for comprehensive utilization of resources in the treatment of wastewater from the production of cyclopentadecanol flavorings according to claim 7, characterized in that, The condensate receiving tank (5-6) is connected to the condensate storage tank (6) via a pipe. The solid-liquid separation tank (5-9) is connected to the crystallization vessel (7) via a pipe. The crystallization vessel (7) is connected to the ethanol high-level tank (8) and the centrifuge (9) via pipes. The centrifuge (9) is connected to the mother liquor tank (10) via a pipe. The mother liquor tank (10) is connected to the flash evaporator (11) via a pipe. The flash evaporator (11) is connected to the ethanol receiving tank (13) via the second condenser (12). The ethanol receiving tank (13) is connected to the ethanol high-level tank (8) via a pipe.

9. The method for comprehensive utilization of resources in the treatment of wastewater from the production of cyclopentadecanol flavorings according to claim 8, characterized in that, The settling tank (5-8) and the solid-liquid separation tank (5-9) are connected to a distillation vessel (14) via a pipeline.

10. The method for comprehensive utilization of resources in the treatment of wastewater from the production of cyclopentadecanol flavorings according to claim 9, characterized in that, The fractionating vessel (14) is connected to a toluene vacuum receiving tank (16) via a spiral plate heat exchanger (15), and the toluene vacuum receiving tank (16) is connected to a toluene temporary storage tank (17) via a pipeline.

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