Process for treating wastewater from neopentyl glycol

Abstract

A method of treating waste water of neopentyl glycol is provided, comprising: recovering waste water containing a catalyst from one or more of a hydroxy aldehyde purification process, a neopentyl glycol purification process, and an extractant recovery process, and supplying the waste water to a volatile organic compound separation column; obtaining an upper effluent stream containing the catalyst and a lower effluent stream containing the waste water from which the catalyst has been removed in the volatile organic compound separation column; and supplying the lower effluent stream to a waste water treatment system to treat the waste water.

Description

Technical Field

[0001] Cross-reference to related applications

[0002] This invention claims the benefit of priority to Korean Patent Application No. 10-2022-0114489, filed on September 8, 2022, and Korean Patent Application No. 10-2023-0112002, filed on August 25, 2023, the entire contents of which are incorporated herein by reference.

[0003] This invention relates to a method for treating wastewater from neopentyl glycol, and more specifically, to a method for treating wastewater generated during the neopentyl glycol preparation process. Background Technology

[0004] Neopentyl glycol can usually be prepared by the aldol condensation of isobutyraldehyde and formaldehyde in the presence of a catalyst to form hydroxyneopental, followed by the hydrogenation of hydroxyneopental.

[0005] However, because formaldehyde is used in an aqueous solution to ensure reactivity and flowability, it contains a significant amount of water. Therefore, the water contained in the formaldehyde aqueous solution is treated as wastewater after the aldol condensation reaction. Unresolved catalyst from the aldol purification process is introduced into the wastewater; since the catalyst contains amine groups, it leads to the production of nitrogen oxides (NOx). x The appearance of ).

[0006] That is, when treating wastewater, environmental pollution problems are caused, and as the added catalyst is introduced into the wastewater and discarded, the production cost increases in the process of continuously adding new catalyst.

[0007] Therefore, an environmentally friendly process should be introduced that can further improve economic viability by recovering and reusing the catalyst from discarded wastewater. Summary of the Invention

[0008] Technical issues

[0009] In order to address the problems mentioned in the background art, one object of the present invention is to provide a method for treating neopentyl glycol wastewater that allows for the production of more neopentyl glycol, is environmentally friendly throughout the process, and can further improve economic feasibility.

[0010] Technical solution

[0011] In one general aspect, a method for treating neopentyl glycol wastewater includes: an aldol reaction process, wherein an aldol condensation reaction is carried out between an aqueous formaldehyde solution and isobutyraldehyde in the presence of a catalyst to obtain a first reaction product containing hydroxyneopental; an aldol extraction process, wherein the first reaction product is contacted with an extractant to obtain a raffinate containing a catalyst salt and an extract containing hydroxyneopental; an aldol purification process, wherein the extract is distilled to separate wastewater containing the catalyst, unreacted isobutyraldehyde and the catalyst, and hydroxyneopental; a hydrogenation reaction process, wherein the hydroxyneopental separated in the aldol purification process is hydrogenated to obtain a second reaction product containing neopentyl glycol; and a neopentyl glycol purification process, wherein the second reaction product is distilled to separate the extractant and the catalyst, and a raffinate containing the catalyst salt. The process involves separating the catalyst from wastewater containing the catalyst and neopentyl glycol, and supplying the separated extractant and catalyst to an extractant recovery tower for an extractant recovery process to separate the catalyst-containing wastewater and obtain separated neopentyl glycol. The process includes: recovering the catalyst-containing wastewater from one or more of the aldol purification process, the neopentyl glycol purification process, and the extractant recovery process, and supplying the wastewater to a volatile organic compound (VOC) separation tower; distilling the catalyst-containing wastewater in the VOC separation tower to obtain an upper discharge stream containing the catalyst and a lower discharge stream containing wastewater from which the catalyst has been removed; and supplying the lower discharge stream from the VOC separation tower to a wastewater treatment system to treat the wastewater.

[0012] Beneficial effects

[0013] According to the method for treating neopentyl glycol wastewater of the present invention, the wastewater containing the catalyst is supplied to a volatile organic compound separation tower and distilled to separate the catalyst. Since nitrogen oxides (NOx) can be significantly reduced by supplying the wastewater from which the catalyst has been separated to the wastewater treatment system in a subsequent stage, the amount of NOx can be significantly reduced. x The generation of ) can reduce environmental pollution.

[0014] Furthermore, the catalyst separated in the volatile organic compound separation tower can be recycled to the aldol purification process, allowing for the reuse of the catalyst as a raw material in the aldol reaction. Therefore, the production cost of neopentyl glycol can be reduced, improving the overall economic feasibility of the process. Attached Figure Description

[0015] Figure 1 This is a process flow diagram illustrating a method for treating wastewater generated during the neopentyl glycol preparation process according to an exemplary embodiment of the present invention.

[0016] Figure 2This is a process flow diagram illustrating a method for preparing neopentyl glycol according to an exemplary embodiment of the present invention.

[0017] Figure 3 This is a process flow diagram illustrating a method for treating wastewater generated during the neopentyl glycol preparation process according to a comparative example of the present invention. Detailed Implementation

[0018] The terms and words used in the specification and claims of this invention should not be limited to having common or dictionary meanings, but should be understood to have meanings and concepts consistent with the technical conception of this invention, based on the principle that inventors are able to appropriately define the concepts of the terms in order to best describe their own inventions.

[0019] The term "fluid flow" in this invention can refer to the flow of fluid in a process, or it can refer to the fluid itself flowing in a pipe. Specifically, "fluid flow" can refer to the fluid itself flowing in the pipes connecting each device and the fluid flow. In addition, fluid can refer to gas or liquid, and does not exclude the inclusion of solid substances in the fluid.

[0020] Furthermore, in this invention, in apparatus such as separation towers, extraction towers, purification towers, distillation towers, and recovery towers, unless otherwise specifically stated, the “lower part” of the apparatus refers to a point at 95% to 100% of the height from the top to the bottom of the apparatus, specifically the lowest part (bottom). Similarly, unless otherwise specifically stated, the “upper part” of the apparatus refers to a point at 0% to 5% of the height from the top to the bottom of the apparatus, specifically the highest part (top).

[0021] Furthermore, in this invention, in apparatus such as separation towers, extraction towers, purification towers, distillation towers, and recovery towers, unless otherwise specifically stated, the operating temperature of the apparatus may refer to the temperature of the lower part of the apparatus. Similarly, unless otherwise specifically stated, the operating pressure of the apparatus may refer to the pressure of the upper part of the apparatus.

[0022] In the following text, the invention will be described in more detail for better understanding.

[0023] According to an exemplary embodiment of the present invention, a method for treating neopentyl glycol wastewater is provided, comprising: an aldol reaction process, wherein an aldol condensation reaction is carried out between an aqueous formaldehyde solution and isobutyraldehyde in the presence of a catalyst to obtain a first reaction product containing hydroxyneopental; an aldol extraction process, wherein the first reaction product is contacted with an extractant to obtain a raffinate containing a catalyst salt and an extract containing hydroxyneopental; an aldol purification process, wherein the extract is distilled to separate wastewater containing the catalyst, unreacted isobutyraldehyde and the catalyst, and hydroxyneopental; a hydrogenation reaction process, wherein the hydroxyneopental separated in the aldol purification process is hydrogenated to obtain a second reaction product containing neopentyl glycol; and a neopentyl glycol purification process, wherein the second reaction product is distilled to separate into An extractant and catalyst, wastewater containing the catalyst, and neopentyl glycol are included, and the separated extractant and catalyst are supplied to an extractant recovery tower in which an extractant recovery process is performed to separate the catalyst-containing wastewater and obtain separated neopentyl glycol. The process further includes: recovering the catalyst-containing wastewater from one or more of a hydroxyl purification process, a neopentyl glycol purification process, and an extractant recovery process, and supplying the wastewater to a volatile organic compound (VOC) separation tower; distilling the catalyst-containing wastewater in the VOC separation tower to obtain an upper discharge stream containing the catalyst and a lower discharge stream containing wastewater from which the catalyst has been removed; and supplying the lower discharge stream from the VOC separation tower to a wastewater treatment system for wastewater treatment.

[0024] More specifically, will refer to Figure 2 The present invention will be described in detail.

[0025] First, a method for treating neopentyl glycol wastewater according to an exemplary embodiment of the present invention may include an aldol reaction process 50, in which an aldol condensation reaction is carried out between an aqueous formaldehyde (FA) solution and isobutyraldehyde (IBAL) in the presence of a catalyst to obtain a first reaction product containing hydroxyneopental (HPA).

[0026] Specifically, the aldol reaction process 50 can be carried out in an aldol reactor where the aldol condensation reaction takes place. Since formaldehyde is used in an aqueous solution to ensure reactivity and flowability, it can contain a significant amount of water. The formaldehyde aqueous solution can contain 40% to 64% by weight, more specifically, 45% to 55% by weight of water relative to the total weight of the formaldehyde aqueous solution. Furthermore, methanol may be included to prevent formaldehyde polymerization. In this case, the methanol content can be 0.1% to 15% by weight, more specifically, 0.1% to 5% by weight, relative to the total weight of the formaldehyde aqueous solution.

[0027] Formalin can be used as an aqueous solution of formaldehyde, and a formaldehyde concentration of 35% to 45% by weight can be effective in reducing wastewater.

[0028] Additionally, the catalyst can be an amine compound. Specifically, tertiary amine compounds such as trialkylamine, trimethylamine, triethylamine, tripropylamine, triisopropylamine, and tributylamine are suitable. More specifically, the catalyst may include triethylamine (TEA). In this invention, TEA is most effective in aldol condensation reactions, and therefore it can be used as the catalyst.

[0029] Specifically, in the aldol reaction process 50, the aldol condensation reaction can be carried out at a temperature of 70°C to 100°C and for a time of 0.1 hours to 3 hours. Under these aldol condensation reaction conditions, the aldol condensation reaction between formaldehyde aqueous solution and IBAL can be carried out in the presence of a catalyst to produce a catalyst salt and HPA.

[0030] Here, the catalyst salt can be produced by reacting formic acid, which is generated from the Cannizzaro side reaction occurring in the aldol condensation reaction, with the catalyst.

[0031] In addition, hydroxypentanoic acid-neopentyl glycol ester (HPNE) can be produced through the Tishchenko reaction, another side reaction of aldol condensation.

[0032] Therefore, in the aldol reaction process 50, a first reaction product containing catalyst salt, HPNE and HPA can be obtained, and the first reaction product can be supplied to the aldol extraction tower in which the aldol extraction process 150 is carried out.

[0033] A method for treating neopentyl glycol wastewater according to an exemplary embodiment of the present invention may include an aldol extraction process 150, in which a first reaction product is contacted with an extractant to obtain a raffinate containing a catalyst salt and an extract containing hydroxyneopentaldehyde.

[0034] Specifically, in aldol extraction process 150, a first reaction product containing a catalyst salt, HPNE, and HPA can be contacted with an extractant to obtain an organic extract containing unreacted IBAL, the extractant, and HPA, as well as a raffinate containing the catalyst salt. Here, the unreacted IBAL can be IBAL that has not undergone aldol condensation in aldol reaction process 50. The extract can be supplied to an aldol purification tower in which aldol purification process 200 is carried out, while the raffinate can be supplied to a saponification reactor in which saponification reaction process 60 is carried out.

[0035] Here, the extractant can be a fatty alcohol, preferably 2-ethylhexanol (2-EH). Since the HPA contained in the first reaction product is soluble in 2-EH, 2-EH is preferably used in the aldol extraction process 150 using an extraction apparatus according to the liquid-liquid contact method.

[0036] Meanwhile, the operating temperature of one, two, or more aldol extraction towers performing the aldol extraction process 150 can be between 40°C and 90°C. By operating the aldol extraction towers within this temperature range, the phase can be easily separated into an organic phase and a liquid phase.

[0037] A method for treating neopentyl glycol wastewater according to an exemplary embodiment of the present invention may include a saponification reaction process 60, which saponifies the raffinate obtained in the aldol extraction process 150 to reduce the catalyst salt to the catalyst.

[0038] In the saponification reactor where the saponification reaction process 60 is carried out, the raffinate containing the catalyst salt can be saponified to reduce the catalyst salt to the catalyst. The saponification reaction in the saponification reactor can be carried out by reacting the catalyst salt with an inorganic strong base, such as sodium hydroxide (NaOH) added alone, thereby effectively reusing the reduced catalyst.

[0039] The reduced catalyst can be processed through catalyst recovery process 700, in which the reduced catalyst in the catalyst recovery tower can be distilled to separate the catalyst and wastewater, and the separated catalyst can be recycled to aldol purification process 200.

[0040] Simultaneously, when the separated catalyst is supplied to the aldol reactor in which the aldol reaction process 50 is carried out, excessive side reactions may occur in the aldol reaction process 50, generating a large amount of high-boiling-point nitrogen compounds as byproducts. These high-boiling-point nitrogen compounds are then introduced into the volatile organic compound (VOC) separation tower described later, thereby causing nitrogen oxides (NOx) to form. x The increase of NO. Therefore, the separated catalyst is recycled to the aldol purification process 200 instead of being directly supplied to the aldol reactor in the aldol reaction process 50, thereby further reducing the side reactions in the aldol reaction process 50 to reduce the generation of by-products, and thus further reducing NO. x The presence of [a certain substance] is minimized. Furthermore, the separated catalyst can be purified in an aldol purification tower using the aldol purification process 200, and can be reused as a catalyst with higher purity.

[0041] Furthermore, the present invention may include supplying the wastewater separated from the catalyst recovery process 700 to a VOC separation tower. Therefore, when a portion of the catalyst not separated in the catalyst recovery process 700 is contained in the separated wastewater, a portion of the catalyst contained in the separated wastewater can be recovered in the VOC separation tower.

[0042] A method for treating neopentyl glycol wastewater according to an exemplary embodiment of the present invention may include a distillation extract to separate the wastewater containing the catalyst, unreacted isobutyraldehyde and the catalyst, and a hydroxyl neopentylaldehyde purification process 200.

[0043] Specifically, the aldol purification process 200 can be a process of distilling the catalyst recovered from the catalyst recovery process 700 and the extract separated from the aldol extraction process 150 to separate wastewater containing the catalyst, unreacted IBAL and the catalyst, as well as HPA and the extractant. Here, in addition to the catalyst recovered from the catalyst recovery process 700 and the extract separated from the aldol extraction process 150, the distillate to be distilled in the aldol purification process 200 may also include the catalyst separated from the extractant recovery process 500 and the top effluent stream from the volatile organic compound separation tower described later.

[0044] More specifically, the aldol purification process 200 can be carried out using two or more towers. One or more of the two or more towers may include an aldol purification tower, and the remaining one or more may include a wastewater separation tower.

[0045] First, when the aldol purification tower is configured as a single aldol purification tower, unreacted IBAL and catalyst can be separated from the upper part of the tower, and HPA and extractant can be separated from the lower part. Simultaneously, when the aldol purification tower is configured as two or more aldol purification towers, it can include one or more aldol purification towers for separating unreacted IBAL to the upper part and one or more aldol purification towers for separating catalyst to the upper part. The stream containing HPA or extractant can be separated and discharged into the lower part of the two or more aldol purification towers. Additionally, the unreacted IBAL and / or catalyst separated to the upper part in one or more aldol purification towers can be separated with water.

[0046] Simultaneously, one or more wastewater separation towers can separate wastewater (water) from unreacted IBAL, catalyst, HPA, and extractant. Therefore, the stream supplied to the wastewater separation towers can be a stream containing water separated in one or more aldol purification towers. Furthermore, wastewater recovered from the wastewater separation towers can be supplied to wastewater tank 10, described later. Here, the wastewater supplied to wastewater tank 10 may include small amounts of catalyst and unreacted IBAL that were not separated in the wastewater separation towers.

[0047] According to the present invention, in the aldol purification process 200, the unreacted IBAL and catalyst separated in the aldol purification process 200 can be recycled to the aldol reaction process 50. Therefore, since the catalyst and IBAL used in the aldol reaction process 50 are recovered, the amount of newly added raw materials can be reduced, and the production cost used in this process can be reduced.

[0048] A method for treating neopentyl glycol wastewater according to an exemplary embodiment of the present invention may include a hydrogenation reaction process 70, which hydrogenates hydroxyneopental separated in an aldol purification process 200 to obtain a second reaction product comprising neopentyl glycol.

[0049] In hydrogenation process 70, hydrogenation reaction is carried out with hydrogen separately added from HPA isolated in aldol purification process 200 to obtain a second reaction product containing NPG. Here, the hydrogenation reaction can be carried out at a hydrogen pressure of 100 psig to 1500 psig (pounds per square inch gauge pressure) and a reaction temperature of 100°C to 200°C.

[0050] Furthermore, the hydrogenation reaction can be carried out in the presence of a hydrogenation catalyst. Nickel or copper-based catalysts can be used as hydrogenation catalysts. The nickel catalyst can be 2% to 10% by weight relative to the weight of HPA. Examples of copper-based catalysts include CuO / BaO / SiO catalysts, where CuO / BaO / SiO catalysts can be (CuO) x (BaO) y (SiO) z (x, y, and z are by weight%, x∶y∶z = 10-50∶0-10∶40-90, 10-50∶1-10∶40-89, or 29-50∶1-10∶40-70) catalysts. Based on the sum of x, y, and z (100 wt%), the sum of x and y is preferably 20 (wt%) to 50 (wt%) or 30 (wt%) to 50 (wt%), and within this range, the hydrogenation reaction catalyst exhibits excellent performance and a long lifespan.

[0051] When hydrogen is hydrogenated with HPA, NPG can be produced. Therefore, a second reaction product comprising a catalyst, extractant, NPG, and HPNE can be obtained in hydrogenation process 70. Here, HPNE can be produced as a byproduct of the aldol condensation reaction in aldol process 50. Subsequently, the desired product, neopentyl glycol, can be obtained through NPG purification process 300 of the second reaction product.

[0052] A method for treating neopentyl glycol wastewater according to an exemplary embodiment of the present invention may include a neopentyl glycol purification process 300: distilling a second reaction product to separate an extractant and a catalyst, wastewater containing the catalyst, and neopentyl glycol, and supplying the separated extractant and catalyst to an extractant recovery tower in which an extractant recovery process 500 is performed to separate the wastewater containing the catalyst and to obtain the separated neopentyl glycol.

[0053] Specifically, NPG purification process 300 may be a process in which the second reaction product is distilled to separate wastewater containing the catalyst, an extractant and catalyst, and NPG. The separated extractant and catalyst may be introduced into an extractant recovery process 500, described later, and NPG may be obtained as the intended product in NPG purification process 300.

[0054] In addition, in the NPG purification process 300, HPNE can be further separated from the second reaction product, and the HPNE-containing stream can be introduced into the hydroxypentanoic acid-neopentyl glycol ester (HPNE) purification process.

[0055] Meanwhile, the NPG purification process 300 can be carried out using two or more columns, just as in the aldol purification process 200. One or more of the two or more columns may include an NPG purification column, and the remaining one or more columns may include a wastewater separation column.

[0056] First, when the NPG purification tower is configured as a single NPG purification tower, the extractant and catalyst can be separated from the upper part of the NPG purification tower, HPNE can be separated from the lower part, and NPG can be separated from the side part. Simultaneously, when the NPG purification tower is configured as two or more NPG purification towers, it can include one or more NPG purification towers for separating the extractant to the upper part and one or more NPG purification towers for separating the catalyst to the upper part. The stream containing HPNE or NPG can be separated and discharged into the lower part of the two or more NPG purification towers. Additionally, the stream containing water, i.e., the wastewater stream, can be separated from the catalyst, extractant, HPNE, and NPG separately in one or two or more NPG purification towers.

[0057] Simultaneously, one or more wastewater separation towers can separate wastewater from the catalyst, extractant, HPNE, and NPG. Therefore, the stream supplied to the wastewater separation towers can be the wastewater stream separated from one or more NPG purification towers. Furthermore, the wastewater separation towers can supply the separated wastewater to wastewater tank 10, described later. Here, the wastewater may include catalyst that was not separated in the NPG purification towers.

[0058] Meanwhile, the extractant recovery process 500 of the present invention can be the following process: supplying the catalyst and extractant separated from the neopentyl glycol purification process 300 to a catalyst recovery tower; separating wastewater containing the catalyst, the catalyst, and the extractant; introducing the catalyst into the aldol purification process 200; and introducing the extractant into the aldol extraction process 150. Here, the catalyst can be a small amount of catalyst that was not separated in the aldol extraction process 150 and the aldol purification process 200. Simultaneously, the extractant can be recycled to the aldol extraction process 150 to recover the extractant, for example, 2-EH, and reuse it in the aldol extraction process 150.

[0059] More specifically, the extractant recovery process 500 can be carried out via a tower, namely, an extractant recovery tower. The catalyst can be separated from the upper part of the extractant recovery tower, and the extractant from the lower part. Additionally, a water-containing stream, i.e., a wastewater stream, can be separated from the catalyst and extractant separately in the extractant recovery tower. Furthermore, the wastewater stream separated in the extractant recovery tower can be supplied to a wastewater tank 10, described later. Here, the wastewater may contain a small amount of catalyst.

[0060] Meanwhile, in the HPNE purification process 400 according to an exemplary embodiment of the present invention, the HPNE-containing stream separated from the NPG purification process 300 can be distilled to separate small amounts of NPG and HPNE. Subsequently, the small amount of separated NPG can be refluxed back to the NPG purification process 300, and HPNE can be obtained separately.

[0061] Here, a small amount of NPG is not recovered as a product in the NPG purification process and is separated from HPNE. Furthermore, since NPG can be further recovered from the HPNE purification process 400, the NPG recovery rate can be further improved. Additionally, the obtained HPNE can be used in various ways, for example, as a main raw material for coating and synthetic polyesters, as a high-value-added product. Because HPNE can be used as a raw material in other processes, the economic feasibility of using HPNE in the HPNE purification process 400 is improved.

[0062] In the following text, reference will be made to an exemplary implementation scheme. Figure 1 The invention will now be described in more detail.

[0063] A method for treating NPG wastewater according to an exemplary embodiment of the present invention may include: recovering wastewater containing a catalyst from one or more of a hydroxyl purification process, a neopentyl glycol purification process, and an extractant recovery process, and supplying the wastewater to a volatile organic compound (VOC) separation tower; obtaining an upper fraction containing a catalyst and a lower fraction containing wastewater from which the catalyst has been removed in the VOC separation tower; and supplying the lower fraction to a wastewater treatment system for treating the wastewater.

[0064] First, an exemplary method for treating NPG wastewater may include recovering catalyst-containing wastewater from one or more processes, including a hydroxyl purification process, a neopentyl glycol purification process, and an extractant recovery process, and supplying the wastewater to a VOC separation tower 100.

[0065] Specifically, wastewater separated in one or more towers during one or more of the aldol purification process, NPG purification process, and extractant recovery process can be introduced into wastewater tank 10. Alternatively, wastewater separated from the catalyst recovery process can also be introduced into wastewater tank 10.

[0066] In this way, wastewater separated in multiple processes can be supplied to wastewater tank 10 and, as discharge stream 11 from wastewater tank, to VOC separation tower 100. Here, the wastewater may originate from water contained in the formaldehyde aqueous solution used in the aldol reaction process 50. Furthermore, the wastewater may contain unseparated catalyst and unreacted IBAL from the aldol purification process.

[0067] Meanwhile, as mentioned above, the catalyst in this invention can be, for example, TEA. Since TEA contains amine groups, it can potentially lead to the production of nitrogen oxides (NOx). x The appearance of NO. x It may be harmful to the environment, therefore TAE needs to be separated to reduce NO. x Therefore, in this invention, the catalyst can be separated by the VOC separation tower 100, and the catalyst separated from the VOC separation tower 100 can be recovered and reused.

[0068] A method for treating neopentyl glycol wastewater according to an exemplary embodiment of the present invention may include distilling the wastewater containing the catalyst in a VOC separation tower to obtain an upper discharge stream containing the catalyst and a lower discharge stream containing wastewater from which the catalyst has been removed.

[0069] In VOC separation tower 100, the effluent stream 11 from the wastewater tank can be distilled to separate an upper fraction containing the catalyst and a lower fraction containing wastewater from which the catalyst has been removed. Therefore, as described above, this will promote NO... x The resulting catalyst TEA is used for separation, thereby adjusting the amine component in the lower fraction of the VOC separation column to reduce NO. x The generation of.

[0070] Meanwhile, the operating temperature of the VOC separation tower 100 can be above 50℃, above 60℃, or above 70℃, and below 160℃, below 180℃, or below 200℃. Additionally, the operating pressure of the VOC separation tower 100 can be 0.68 kg / cm³. 2 Above, 1.50 kg / cm 2 Above or 2.00 kg / cm 2 Above, and 4.00 kg / cm 2 Below, 4.50 kg / cm 2 Below or 5.00 kg / cm 2 the following.

[0071] The upper fraction of VOC separation tower 100 can be recycled to the aldol purification process via the upper effluent stream 120 from the VOC separation tower. The upper fraction of VOC separation tower 100 contains catalyst and unreacted IBAL, which can be reused by recycling them to the aldol purification process. The catalyst can thus be recovered and reused, thereby reducing NO. x The production of this technology ensures that the process is cost-competitive while being environmentally friendly.

[0072] Meanwhile, the lower fraction of the VOC separation tower 100, which contains wastewater from which the catalyst has been separated, can be supplied to the evaporator 20 through the lower discharge stream 110 of the VOC separation tower.

[0073] According to an exemplary embodiment of the invention, the catalyst content in the lower effluent stream 110 of the VOC separation tower may be less than 5.0% by weight, more specifically, less than 4.0% by weight or less than 3.0% by weight. The catalyst is included within this range, thereby reducing the amine component in the stream introduced into the wastewater treatment system 30 described later, in order to reduce NO in the wastewater treatment system 30. X The generation of.

[0074] According to an exemplary embodiment of the present invention, the lower discharge stream from the VOC separation tower is supplied to the evaporator 20 to remove sludge, and the upper fraction of the evaporator from which the sludge has been removed can be supplied to the wastewater treatment system 30.

[0075] The lower discharge stream 110 from the VOC separation tower, containing wastewater separated from the catalyst, can be evaporated in evaporator 20, thereby separating it into a lower fraction containing sludge and an upper fraction containing gaseous components from which the sludge has been removed. The lower fraction can be supplied to sludge dryer 40 via lower discharge stream 21, and the upper fraction can be supplied to wastewater treatment system 30 via upper discharge stream 22.

[0076] Meanwhile, in the sludge dryer 40, the sludge contained in the lower discharge stream 21 from the evaporator can be dried and treated as waste or burned for use as energy for the process.

[0077] A method for treating neopentyl glycol wastewater according to an exemplary embodiment of the present invention may include supplying the lower discharge stream from the VOC separation tower to a wastewater treatment system and treating the wastewater.

[0078] Specifically, in the wastewater treatment system 30, the lower discharge stream from the VOC separation tower, i.e., the upper discharge stream 22 from the evaporator, which has already passed through the evaporator 20, is treated as wastewater to obtain a waste gas discharge stream 32 containing waste gas and a wastewater discharge stream 31 containing wastewater. Here, the waste gas can be a gas from which amine groups have been removed.

[0079] More specifically, a wastewater treatment system is a system that performs processes to treat organic matter present in water, and can utilize regenerative thermal oxidizers (RTO), DeNOx, etc. x Systems such as these are used for wastewater treatment.

[0080] A regenerative thermal oxidizer is a facility that recovers the heat generated during incineration of gaseous components containing organic matter through ceramic packing material with a large surface area and semi-permanent use, thereby significantly reducing the operating costs of the incinerator. Furthermore, regenerative thermal oxidizers have a treatment efficiency of over 99%, which is very high, with a low secondary pollution coefficient.

[0081] Meanwhile, DeNO x The system removes nitrogen oxides through selective catalytic reduction (SCR). SCR allows gaseous components containing nitrogen oxides generated during the process to pass through a catalyst bed containing a reducing agent (ammonia or urea) to decompose the gaseous components into nitrogen and water vapor, which are then released into the atmosphere.

[0082] As described above, catalysts such as TEA are pre-removed through a VOC recovery tower to remove TEA introduced into the wastewater treatment system, thereby reducing NO generated in the wastewater treatment system. x The amount of NPG prepared is thus environmentally friendly. Additionally, the catalyst separated and recovered in the VOC recovery tower is recycled to the aldol purification process for further purification, and the purified catalyst is placed in a suitable condition for reuse in the aldol reaction process 50.

[0083] As another example, the VOC separation tower can be a divider wall tower (DWC). When using a divider wall tower (DWC) as the VOC separation tower, a separate evaporator and subsequent wastewater treatment system are not required, thus simplifying the process and enabling efficient management. Additionally, the energy consumption of thermal integration can be reduced.

[0084] More specifically, a partition wall column is a distillation column with a partition wall. Because the space provided by the partition wall is divided into two parts, functions such as merging two distillation columns into one can be performed. Therefore, the catalyst and unreacted IBAL can be separated into an upper fraction, the sludge into a lower fraction, and the wastewater into a side fraction.

[0085] The lower fraction of the VOC separation tower containing sludge can be supplied to the sludge dryer and dried via the lower discharge stream from the VOC separation tower, and the side fraction of the VOC separation tower 100 containing wastewater can be discharged from the VOC separation tower via the side discharge stream 130.

[0086] Additionally, as mentioned above, the top fraction of the VOC separation tower, containing the catalyst and unreacted IBAL, can be recycled as the top effluent from the VOC separation tower to the aldol purification process. The catalyst can be purified and recovered in the aldol purification process, and the recovered catalyst can be recycled to the aldol reaction process 50 and reused as a feedstock for the aldol condensation reaction.

[0087] The invention will be described in more detail below by way of examples. However, the following examples are provided to illustrate the invention. It will be apparent to those skilled in the art that various modifications and alterations can be made without departing from the scope and concept of the invention, and the scope of the invention is not limited thereto.

[0088] Example

[0089] Example 1

[0090] according to Figure 1 The process flow shown in the image simulates the neopentyl glycol (NPG) wastewater treatment process using the Aspen Plus simulator provided by Aspen.

[0091] In an aldol reactor, an aldol condensation reaction is carried out between an aqueous formaldehyde solution and isobutyraldehyde in the presence of a catalyst (triethylamine, TEA) to obtain a first reaction product containing hydroxypentylaldehyde (aldol reaction process).

[0092] The first reaction product is contacted with an extractant (2-ethylhexanol, 2-EH) to obtain a raffinate containing a catalyst salt, an extract containing hydroxypentanal, and wastewater containing the catalyst (hydroxyal extraction process).

[0093] The raffinate is saponified to reduce the catalyst salt to the catalyst, thus obtaining the reduced catalyst (saponification reaction process). The reduced catalyst is then distilled in a catalyst recovery tower to separate the wastewater containing the catalyst from the catalyst, and the catalyst is recovered (catalyst recovery process).

[0094] The catalyst separated from the catalyst recovery process and the extract obtained from the aldol extraction process are distilled in an aldol purification tower to separate unreacted isobutyraldehyde and catalyst, wastewater containing the catalyst, and hydroxypentylaldehyde. The separated unreacted isobutyraldehyde and catalyst are recycled to the aldol reaction process (aldol purification process).

[0095] Simultaneously, the hydroxypentylaldehyde separated from the aldol purification process is hydrogenated to obtain a second reaction product containing neopentyl glycol (hydrogenation reaction process).

[0096] The second reaction product is distilled to separate the wastewater containing the catalyst, extractant and catalyst, neopentyl glycol, and hydroxypentyl-neopentyl glycol ester (HPNE) to obtain neopentyl glycol as the product (NPG purification process).

[0097] The extractant and catalyst separated from the NPG purification process are then processed through an extractant recovery process to separate the wastewater containing the catalyst, the extractant, and the catalyst, respectively. The extractant separated from the extractant recovery process is recycled to the aldol extraction process, and the catalyst separated from the extractant recovery process is recycled to the aldol purification process.

[0098] Simultaneously, the stream containing HPNE separated from the NPG purification process is recycled to the HPNE purification process to separate NPG and HPNE. The NPG separated from the HPNE purification process is recycled to the NPG purification process, yielding HPNE separately.

[0099] The wastewater containing the catalyst is recovered from the catalyst recovery process, the aldol purification process, the neopentyl glycol purification process, and the extractant recovery process, and introduced into the wastewater tank 10.

[0100] The catalyst-containing wastewater introduced into wastewater tank 10 is supplied as effluent stream 11 from the wastewater tank to volatile organic compound (VOC) separation tower 100. In VOC separation tower 100, an upper fraction containing the catalyst and a lower fraction containing wastewater from which the catalyst has been removed are separated. At this time, the operating temperature of VOC separation tower 100 is 110°C, and its operating pressure is 1.1 kg / cm³. 2 .

[0101] The upper fraction containing the catalyst is recycled to the aldol purification process via the upper discharge stream 120 from the VOC separation tower, and the lower fraction containing wastewater from which the catalyst has been removed is supplied to the evaporator 20 via the lower discharge stream 110 from the VOC separation tower.

[0102] The lower effluent 110 from the VOC separation tower is evaporated in evaporator 20, thereby separating the lower fraction containing sludge from the upper fraction containing gaseous components from which sludge has been separated. The lower fraction containing sludge is supplied as lower effluent 21 from the evaporator to sludge dryer 40, and the upper fraction containing gaseous components from which sludge has been separated is supplied as upper effluent 22 from the evaporator to wastewater treatment system 30.

[0103] In the wastewater treatment system 30, the upper discharge stream 22 from the evaporator is treated to separate waste gas and wastewater. The waste gas is discharged through the waste gas discharge stream 32, and the wastewater is discharged through the wastewater discharge stream 31.

[0104] Example 2

[0105] In Example 2, except that the catalyst separated from the catalyst recovery process is recycled to the hydroxyl reactor in which the hydroxyl reaction process is carried out, instead of the hydroxyl purification process, the NPG wastewater is treated by the same process flow as in Example 1.

[0106] Comparative example

[0107] Comparative Example 1

[0108] according to Figure 3 The process flow shown in the image simulates the neopentyl glycol (NPG) wastewater treatment process using the Aspen Plus simulator provided by Aspen.

[0109] In Comparative Example 1, NPG was prepared using the same process as in Example 1, except that no VOC separation tower was installed and the effluent stream 11 from the wastewater tank was supplied to the evaporator 20.

[0110] Table 1 below shows the TEA content in the feed streams of the examples and comparative examples, as well as the TEA content and NO generated in the wastewater treatment system. x The amount.

[0111] Specifically, the TEA content in a wastewater treatment system can be defined as the ratio of the weight of TEA in the stream supplied to the wastewater treatment system to the total weight of the stream supplied to the wastewater treatment system (the stream discharged from the top of the evaporator).

[0112] At the same time, the generated NO x The quantity represents the amount of nitrogen oxides (NOx) contained in the exhaust gas stream 32 of the wastewater treatment system. x The component relative to the total weight of the waste gas discharge stream 32 of the wastewater treatment system.

[0113] [Table 1]

[0114]

[0115]

[0116] Referring to Table 1, it has been confirmed that, compared with Comparative Example 1, the NO in the examples is lower. x The amount produced was reduced. However, it has been confirmed that Comparative Example 1, which did not have a VOC separation tower, had the highest NO content compared to the Example. x Production volume.

Claims

1. A method of treating waste water of neopentyl glycol, the method comprising: a hydroxy aldehyde reaction process of conducting a hydroxy aldehyde condensation reaction between an aqueous formaldehyde solution and isobutyraldehyde in the presence of a catalyst to produce a first reaction product comprising hydroxy neopentanal; a hydroxy aldehyde extraction process of contacting the first reaction product with an extractant to produce a raffinate comprising a catalyst salt and an extract comprising hydroxy neopentanal; a hydroxy aldehyde purification process of distilling the extract to separate into waste water comprising the catalyst, unreacted isobutyraldehyde and the catalyst, and hydroxy neopentanal; a hydrogenation reaction process of hydrogenating the hydroxy neopentanal separated in the hydroxy aldehyde purification process to produce a second reaction product comprising neopentyl glycol; and a neopentyl glycol purification process of distilling the second reaction product to separate into the extractant and the catalyst, waste water comprising the catalyst, and neopentyl glycol, and supplying the separated extractant and catalyst to an extractant recovery column in which an extractant recovery process is conducted to separate waste water comprising the catalyst and produce separated neopentyl glycol, and including: recovering the waste water comprising the catalyst from one or more of the hydroxy aldehyde purification process, the neopentyl glycol purification process, and the extractant recovery process, and supplying the waste water comprising the catalyst to a volatile organic compound separation column; distilling the waste water comprising the catalyst in the volatile organic compound separation column to produce an upper take-off stream comprising the catalyst and a lower take-off stream comprising waste water from which the catalyst has been removed; supplying the lower take-off stream from the volatile organic compound separation column to a waste water treatment system to treat the waste water, and recycling the upper take-off stream from the volatile organic compound separation column to the hydroxy aldehyde purification process.

2. The method of treating waste water of neopentyl glycol according to claim 1, wherein, the hydroxy aldehyde purification process is a process of recycling separated unreacted isobutyraldehyde and catalyst to the hydroxy aldehyde reaction process.

3. The method of treating wastewater from neopentyl glycol according to claim 1, further comprising: a saponification reaction process of saponifying the raffinate resulting from the hydroxy aldehyde extraction process to reduce the catalyst salt to the catalyst.

4. The method of treating wastewater from neopentyl glycol according to claim 3, further comprising: a catalyst recovery process of distilling the catalyst reduced in the saponification reaction process to separate waste water from the catalyst, and recycling the separated catalyst to the hydroxy aldehyde purification process.

5. The method of treating wastewater from neopentyl glycol according to claim 4, further comprising: the waste water separated from the catalyst recovery process is supplied to the volatile organic compound separation column.

6. The method of treating wastewater from neopentyl glycol according to claim 1, wherein, the extractant recovery process is a process of supplying the catalyst and the extractant separated from the neopentyl glycol purification process to the extractant recovery column, separating the waste water comprising the catalyst, the catalyst, and the extractant, introducing the catalyst to the hydroxy aldehyde purification process, and introducing the extractant to the hydroxy aldehyde extraction process.

7. The method of treating waste water of neopentyl glycol according to claim 1, wherein the neopentyl glycol purification process is a process of further separating hydroxypivalic acid-neopentyl glycol ester (HPNE) from the second reaction product, and the neopentyl glycol purification process is a process of further separating hydroxypivalic acid-neopentyl glycol ester (HPNE) from the second reaction product, and Further comprising distilling a stream comprising hydroxypivalic acid-pivalin ester (HPNE) separated from the pivalin purification process and recycling a small amount of pivalin to the pivalin purification process to obtain a hydroxypivalic acid-pivalin ester purification process of hydroxypivalic acid-pivalin ester.

8. The method of treating wastewater from neopentyl glycol according to claim 1, wherein, The catalyst comprises triethylamine (TEA).

9. The method of treating wastewater from neopentyl glycol according to claim 1, wherein, The extractant comprises 2-ethylhexanol (2-EH).

10. The method of treating wastewater from neopentyl glycol according to claim 1, wherein, The content of the catalyst in the lower discharge stream from the volatile organic compound separation column is 5.0 wt% or less.

11. The method of treating wastewater from a pivalin purification process according to claim 1, further comprising supplying the lower discharge stream from the volatile organic compound separation column to an evaporator, removing sludge, and supplying an upper fraction of the evaporator from which sludge has been removed to the wastewater treatment system.

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