Pretreatment system for salt-containing wastewater discharged in epoxy resin production

Abstract

The utility model relates to a pretreatment system for salt-containing wastewater discharged in epoxy resin production. The salt-containing wastewater pretreatment system comprises a filter, a mixer, an extraction tower and flash evaporation equipment; the filter, the mixer, the extraction tower and the flash evaporation equipment are sequentially connected; the filter is used for removing suspended waste polymers; the mixer is used for fully mixing the salt-containing wastewater and the extraction agent; and the extraction tower is used for separating the salt-containing wastewater and residual entrained epoxy resin. Compared with the prior art, the device has the advantages that the mixer, the extraction tower and the flash evaporation equipment are arranged, so that the salt-containing wastewater and the extraction agent are fully mixed and then are separated, a small amount of residual entrained epoxy resin is removed, and residual methylbenzene in the salt-containing wastewater is removed, so that the phenomenon that the salt-containing wastewater enters an external multi-effect evaporation and concentration system subsequently can be effectively prevented; the generation and accumulation of tar substances in the evaporator enable the evaporator not to be blocked easily, and stable operation of an external multi-effect evaporation, concentration and crystallization system is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of salt-containing wastewater pretreatment, in particular to a salt-containing wastewater pretreatment system discharged from epoxy resin production. Background Art

[0002] Salt-containing wastewater is generated during the production of epoxy resin. Taking the "two-step method" to produce liquid epoxy resin E51 as an example, for every ton of product produced, about 1.5 tons of salt-containing wastewater (sodium chloride content of about 20% to 25%) is generated. This salt-containing wastewater has the characteristics of high salt and high COD.

[0003] At present, the conventional treatment process for salt-containing wastewater discharged from epoxy resin production is to extract sodium chloride from the wastewater through a multiple-effect evaporation concentration crystallization system. The multiple-effect evaporation concentration crystallization system is composed of multiple evaporators connected in series. The wastewater is concentrated from the first effect to the last effect in sequence, and sodium chloride is crystallized out in the last effect when it reaches supersaturation, thereby achieving solid-liquid separation of the feed liquid; the secondary wastewater obtained after separation is passed through a biochemical treatment system and treated to meet the discharge standards.

[0004] However, the sodium chloride extracted by this method contains a large amount of resin waste polymers, which cannot meet the requirements of the group standard "Industrial Sodium Chloride as a Byproduct of Epoxy Resin" (T / CPCIF 0068-2020) for the "total organic carbon content" of by-product industrial sodium chloride. In addition, after the multi-effect evaporation concentration crystallization system has been running for a certain period of time, tar-like substances appear in the evaporator, resulting in a decrease in the evaporation capacity of the evaporator; as the evaporation device continues to operate, the tar-like substances gradually accumulate and mix with the sodium chloride, blocking the evaporator extremely hard until the multi-effect evaporation concentration crystallization system cannot operate normally.

[0005] Therefore, it is urgent to study a salt-containing wastewater pretreatment system that can effectively solve the above two problems so that the "total organic carbon content" in the extracted sodium chloride can meet the requirements of the group standard "Industrial Sodium Chloride as a By-product of Epoxy Resin" (T / CPCIF 0068-2020); and the evaporator is not easy to be blocked, ensuring the stable operation of the multi-effect evaporation concentration crystallization system. Utility Model Content

[0006] The purpose of the utility model is to provide a pretreatment system for saline wastewater discharged from epoxy resin production in order to overcome the defects of the above-mentioned prior art. By setting a mixer, an extraction tower and a flash evaporation device, the saline wastewater and the extractant are fully mixed and then separated, thereby removing a small amount of residual entrained epoxy resin and removing the residual extractant in the saline wastewater.

[0007] The purpose of the utility model can be achieved through the following technical solutions:

[0008] The utility model provides a pretreatment system for saline wastewater discharged from epoxy resin production, comprising a filter, a mixer, an extraction tower and a flash evaporation device;

[0009] The filter, mixer, extraction tower and flash evaporation equipment are connected in sequence;

[0010] The filter is used to remove suspended waste polymers;

[0011] The mixer is used to fully mix the saline wastewater and the extractant;

[0012] The extraction tower is used to separate the saline wastewater and the residual entrained epoxy resin;

[0013] The salt-containing wastewater discharged from the production of epoxy resin is input from the filter, filtered to remove suspended waste polymers and then sent to the mixer; the salt-containing wastewater is mixed with the extractant in the mixer and sent to the extraction tower for extraction and separation; the salt-containing wastewater after extraction and separation is sent to the flash evaporation equipment for heating and stratification.

[0014] Furthermore, a first discharge port is provided at the upper part of the filter, and a first feed port is provided at the middle part of the filter, wherein the first discharge port is used for outputting the filtered saline wastewater, and the first feed port is used for conveying the saline wastewater;

[0015] The bottom end of the filter is provided with a waste polymer discharge port.

[0016] Furthermore, the mixer is a pipeline mixer, and the pipeline mixer is provided with a second feed inlet, a second discharge inlet and an extractant feed inlet;

[0017] The second feed port is connected to the first discharge port of the filter;

[0018] The second discharge port is connected to the middle part of the extraction tower, and the second discharge port is used to transport the mixed solution of the salt-containing wastewater and the extractant to the extraction tower.

[0019] Furthermore, the extraction tower is a TDS extraction tower, the upper part of the TDS extraction tower is provided with a toluene resin solution discharge port and a resin intermediate phase discharge port, the middle part is provided with a third feed port, and the bottom part is provided with a third discharge port;

[0020] The third feed port is connected to the second discharge port of the pipeline mixer, and the third discharge port is connected to the flash evaporation device, so as to input the saline wastewater into the flash evaporation device.

[0021] Further, the flash evaporation equipment includes a flash evaporation heater, a flash evaporation tower, a flash evaporation tower condenser and a chromatography tank;

[0022] The flash heater, the flash tower, and the flash tower condenser are connected in sequence;

[0023] The chromatography tank is connected to the flash tower condenser.

[0024] Furthermore, one end of the flash heater is provided with a fourth feed port and a steam condensate discharge port, and the other end is provided with a steam feed port and a fourth discharge port;

[0025] The fourth feed port is connected to the third discharge port of the extraction tower, and the fourth discharge port is connected to the middle part of the flash tower.

[0026] Furthermore, a fifth discharge port is provided at the bottom end of the flash tower, an extractant discharge port is provided at the top end of the flash tower, and a fifth feed port is provided at the middle of the flash tower;

[0027] The fifth discharge port is connected to an external multi-effect evaporation concentration crystallization system, and the fifth feed port is connected to a fourth discharge port of the flash heater.

[0028] Furthermore, one end of the flash tower condenser is provided with an extractant feed port and a circulating water return water discharge port, and the other end is provided with a vacuum pipeline, a sixth discharge port and a circulating water feed port;

[0029] The extractant feed port is connected to the extractant discharge port on the flash tower, and the sixth discharge port is connected to the top of the chromatography tank.

[0030] Furthermore, a sixth feed port and an extractant discharge port are provided at the upper portion of the chromatography tank, and the bottom of the chromatography tank is connected to a pipeline of an external biochemical treatment system.

[0031] Furthermore, the flash evaporation equipment also includes a vacuum pump, one end of the vacuum pipeline is connected to the flash tower condenser, and the other end is connected to the vacuum pump.

[0032] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0033] 1. The utility model provides a mixer, an extraction tower and a flash evaporation device to fully mix the saline wastewater and the extractant and then separate them, thereby removing a small amount of residual epoxy resin and removing residual toluene in the saline wastewater. The sodium chloride precipitated after the pretreated saline wastewater enters the external multi-effect evaporation concentration crystallization system can meet the requirements of the group standard "Industrial Sodium Chloride as a Byproduct of Epoxy Resin" (T / CPCIF 0068-2020) for the "total organic carbon content" of by-product industrial sodium chloride, and can be sold as industrial sodium chloride, bringing significant economic benefits.

[0034] 2. The utility model removes a small amount of epoxy resin and waste polymers remaining in the saline wastewater, and can effectively prevent the subsequent generation and accumulation of tar-like substances in the evaporator in the external multiple-effect evaporation concentration system, making the evaporator less likely to be blocked, thereby ensuring the stable operation of the external multiple-effect evaporation concentration crystallization system.

[0035] 3. The utility model recovers epoxy resin in saline wastewater by setting up a TDS extraction tower, thereby increasing the yield of epoxy resin production in disguise. By evaporating a portion of the water in the saline wastewater in the flash evaporation device, the processing load of the subsequent external multi-effect evaporation concentration system is reduced.

[0036] 4. The utility model adopts DCS automatic control, which is convenient for operation and management and has high safety and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of a saline wastewater pretreatment system discharged from epoxy resin production.

[0038] Description of the markings in the figure:

[0039] 1-filter, 2-mixer, 3-extraction tower, 4-flash heater, 5-flash tower, 6-flash tower condenser, 7-vacuum pump, 8-chromatography tank. DETAILED DESCRIPTION

[0040] The specific implementation methods of the utility model are described in detail below through examples. These examples are implemented on the premise of the scheme described in the utility model, and provide detailed implementation methods and specific operating processes, but the protection scope of the utility model is not limited to the following examples.

[0041] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0042] Example 1

[0043] This embodiment provides a system for pre-treating saline wastewater discharged from epoxy resin production, such as Figure 1 As shown, the filter 1, the mixer 2, the extraction tower 3 and the flash evaporation device are connected in sequence. The filter 1 is used to remove suspended waste polymers; the mixer 2 is used to fully mix the salt-containing wastewater and the extractant; the extraction tower 3 is used to separate the salt-containing wastewater and the residual entrained epoxy resin.

[0044] like Figure 1As shown, the salt-containing wastewater discharged from the production of epoxy resin is transported to the filter 1, filtered to remove the suspended waste polymers, and then transported to the mixer 2; the salt-containing wastewater is mixed with the extractant in the mixer 2 to obtain the salt-containing wastewater containing the extractant, and then the salt-containing wastewater containing the extractant is transported to the extraction tower 3 for extraction and separation; the salt-containing wastewater after extraction and separation is sent to the flash evaporation equipment for heating and stratification, and finally the extractant is recovered, the wastewater is sent to the external biochemical treatment system, and the liquid phase is sent to the external multi-effect evaporation concentration crystallization system to achieve the pretreatment of the salt-containing wastewater. The extractant is toluene.

[0045] The filter 1 has a first discharge port at the top and a first feed port at the middle, both of which are used to transport saline wastewater; and a waste polymer discharge port is provided at the bottom of the filter 1. The filter has an operating pressure of normal pressure to 0.8 MPaG and an operating temperature of normal temperature to 80°C.

[0046] The mixer 2 is a pipeline mixer, which is provided with a second feed port, a second discharge port and an extractant feed port. The second feed port is connected to the first discharge port of the filter 1 through a pipeline, and the second feed port is used to transport the saline wastewater to the pipeline mixer; the second discharge port is connected to the middle of the extraction tower 3, and the second discharge port is used to transport the mixed solution of the saline wastewater and the extractant to the extraction tower 3.

[0047] The extraction tower 3 is a TDS extraction tower, which has a toluene resin solution discharge port and a resin intermediate phase discharge port at the top, a third feed port at the middle, and a third discharge port at the bottom. The third feed port is connected to the second discharge port of the pipeline mixer, and the third discharge port is connected to the flash evaporation device to input the salt-containing wastewater into the flash evaporation device. The operating temperature of the TDS extraction tower is room temperature to 80°C, and the operating pressure is normal pressure.

[0048] The flash evaporation equipment includes a flash heater 4, a flash tower 5, a flash tower condenser 6, a chromatography tank 8 and a vacuum pump 7. The flash heater 4, the flash tower 5 and the flash tower condenser 6 are connected in sequence; the chromatography tank 8 is connected to the flash tower condenser 6. A fourth feed port and a steam condensate discharge port are provided at one end of the flash heater 4, and a steam feed port and a fourth discharge port are provided at the other end. The fourth feed port is connected to the third discharge port of the extraction tower 3, and is used to transport the salt-containing wastewater to the flash heater 4; the fourth discharge port is connected to the middle of the flash tower 5. A fifth discharge port is provided at the bottom end of the flash tower 5, and the fifth discharge port is connected to an external multi-effect evaporation concentration crystallization system. An extractant discharge port is provided at the top of the flash tower 5, and a fifth feed port is provided in the middle of the flash tower 5, and the fifth feed port is connected to the fourth discharge port of the flash heater 4. The operating temperature of the flash tower 5 is 60-120°C, and the operating pressure is -0.09MPa to normal pressure. One end of the flash tower condenser 6 is provided with an extractant feed port and a circulating water return water discharge port, and the other end is provided with a vacuum pipeline, a sixth discharge port and a circulating water upper water feed port; the extractant feed port is connected to the extractant discharge port on the flash tower 5, and the sixth discharge port is connected to the top of the chromatography tank 8. The upper part of the chromatography tank 8 is provided with a sixth feed port and an extractant discharge port, and the bottom of the chromatography tank 8 is connected to the external biochemical treatment system pipeline. One end of the vacuum pipeline is connected to the flash tower condenser 6, and the other end is connected to the vacuum pump 7.

[0049] Application Example 1

[0050] The salt-containing wastewater discharged from a certain epoxy resin production device is transported to the salt-containing wastewater pretreatment system of the utility model. The specific data are as follows:

[0051] Wastewater volume is 7.5m 3 / h (sodium chloride content 23wt.%), filtered (operating temperature 60°C, operating pressure 0.6MPa), mixed (the amount of toluene added as the extractant is 1m 3 / h), TDS extraction (operating temperature is 55℃, operating pressure is normal pressure), flash evaporation (operating temperature is 100℃, operating pressure is -0.075MPa), 7.1m 3 / h salt-containing wastewater, which is transported to an external multi-effect evaporation concentration system to recover 1.02m toluene resin solution 3 / h.

[0052] Application Example 2

[0053] The salt-containing wastewater discharged from a certain epoxy resin production device is transported to the salt-containing wastewater pretreatment system of the utility model. The specific data are as follows:

[0054] Wastewater volume: 23m 3 / h (sodium chloride content 22wt.%), filtered (operating temperature 80°C, operating pressure 0.6MPa), mixed (the amount of toluene added as the extractant is 2m 3 / h), TDS extraction (operating temperature is 75℃, operating pressure is normal pressure), flash evaporation (operating temperature is 110℃, operating pressure is -0.075MPa), 21.2m 3 / h salt-containing wastewater, which is transported to an external multi-effect evaporation concentration system to recover 2.05m3 of toluene resin solution 3 / h.

[0055] The above description of the embodiments is to facilitate the understanding and use of the utility model by those skilled in the art. It is obvious that those familiar with the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the utility model is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the utility model without departing from the scope of the utility model should be within the scope of protection of the utility model.

Claims

1. A pretreatment system for saline wastewater discharged from epoxy resin production, It is characterized in that It comprises a filter (1), a mixer (2), an extraction tower (3) and a flash evaporation device; The filter (1), mixer (2), extraction tower (3) and flash evaporation equipment are connected in sequence; The filter (1) is used to remove suspended waste polymers; The mixer (2) is used to fully mix the saline wastewater and the extractant; The extraction tower (3) is used to separate the salt-containing wastewater and the residual entrained epoxy resin; The salt-containing wastewater discharged from the production of epoxy resin is input from the filter (1), filtered to remove suspended waste polymers and then sent to the mixer (2); the salt-containing wastewater is mixed with an extractant in the mixer (2) and sent to an extraction tower (3) for extraction and separation; the salt-containing wastewater after extraction and separation is sent to a flash evaporation device for heating and stratification.

2. A system for pretreating saline wastewater discharged from epoxy resin production according to claim 1, It is characterized in that The filter (1) is provided with a first discharge port at the top, and a first feed port is provided at the middle of the filter (1), wherein the first discharge port is used for outputting the salt-containing wastewater after filtration, and the first feed port is used for conveying the salt-containing wastewater; The bottom end of the filter (1) is provided with a waste polymer discharge port.

3. A system for pretreating saline wastewater discharged from epoxy resin production according to claim 1, It is characterized in that The mixer (2) is a pipeline mixer, and the pipeline mixer is provided with a second feed inlet, a second discharge inlet and an extractant feed inlet; The second feed port is connected to the first discharge port of the filter (1); The second discharge port is connected to the middle part of the extraction tower (3), and the second discharge port is used to transport the mixed solution of the salt-containing wastewater and the extractant to the extraction tower (3).

4. A system for pretreating saline wastewater discharged from epoxy resin production according to claim 1, It is characterized in that The extraction tower (3) is a TDS extraction tower, the upper part of the TDS extraction tower is provided with a toluene resin solution discharge port and a resin intermediate phase discharge port, the middle part is provided with a third feed port, and the bottom part is provided with a third discharge port; The third feed port is connected to the second discharge port of the pipeline mixer (2), and the third discharge port is connected to the flash evaporation device, so as to input the salt-containing wastewater into the flash evaporation device.

5. A system for pretreating saline wastewater discharged from epoxy resin production according to claim 1, It is characterized in that The flash evaporation equipment comprises a flash evaporation heater (4), a flash evaporation tower (5), a flash evaporation tower condenser (6) and a chromatography tank (8); The flash heater (4), the flash tower (5), and the flash tower condenser (6) are connected in sequence; The chromatography tank (8) is connected to the flash tower condenser (6).

6. A system for pretreating saline wastewater discharged from epoxy resin production according to claim 5, It is characterized in that The flash heater (4) is provided with a fourth feed port and a steam condensate discharge port at one end, and a steam feed port and a fourth discharge port at the other end; The fourth feed port is connected to the third discharge port of the extraction tower (3), and the fourth discharge port is connected to the middle part of the flash tower (5).

7. A system for pretreating saline wastewater discharged from epoxy resin production according to claim 5, It is characterized in that The bottom end of the flash tower (5) is provided with a fifth discharge port, the top end of the flash tower (5) is provided with an extractant discharge port, and the middle part of the flash tower (5) is provided with a fifth feed port; The fifth discharge port is connected to an external multi-effect evaporation concentration crystallization system, and the fifth feed port is connected to a fourth discharge port of a flash heater (4).

8. A system for pretreating saline wastewater discharged from epoxy resin production according to claim 5, It is characterized in that The flash tower condenser (6) is provided with an extractant feed port and a circulating water return discharge port at one end, and a vacuum pipeline, a sixth discharge port and a circulating water feed port at the other end; The extractant feed port is connected to the extractant discharge port on the flash tower (5), and the sixth discharge port is connected to the top of the chromatography tank (8).

9. A system for pretreating saline wastewater discharged from epoxy resin production according to claim 5, It is characterized in that The upper part of the chromatography tank (8) is provided with a sixth feed inlet and an extractant discharge port, and the bottom of the chromatography tank (8) is connected to a pipeline of an external biochemical treatment system.

10. A system for pretreating saline wastewater discharged from epoxy resin production according to claim 5, It is characterized in that The flash evaporation equipment further comprises a vacuum pump (7), one end of a vacuum pipeline is connected to the condenser of the flash evaporation tower (5), and the other end is connected to the vacuum pump (7).

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