Esterification water treatment device

Abstract

The utility model provides an esterification water treatment device which is characterized in that an esterification water tank is connected with a storage tank through a first pipeline, and an alkali liquor tank is connected with the first pipeline through a second pipeline; a pH meter is arranged below the intersection of the first pipeline and the second pipeline; an automatic control module is arranged between the alkali liquor tank and the storage tank and comprises a controller. The input end of the controller is connected with the pH meter, and the output end is connected with the metering pump on the second pipeline. The esterification water tank, the alkaline water tank and the storage tank are separated, the stability of adjusting the pH value of the esterification water is improved, the operation of the device is not influenced by subsequent addition of the esterification water, the alkaline liquid is mixed in the pipeline, the effect is stable and uniform, and the adjustment is convenient and accurate.

Description

TECHNICAL FIELD

[0001] The utility model relates to wastewater treatment technical field, especially esterification water treatment device. BACKGROUND

[0002] In the normal production process of polyester, a part of organic matter in the byproduct water of esterification reaction cannot be completely treated, mainly because the required temperature of esterification reaction is high, and the boiling point of raw material ethylene glycol is lower than the reaction temperature. During the reaction, ethylene glycol evaporates and the byproduct water is mixed together to enter the process tower for cooling. The process tower separates and purifies the ethylene glycol through layer-by-layer cooling according to the different boiling points of ethylene glycol and water. The esterification byproduct water enters the stripping tower for further separation after cooling, and finally is treated by biochemical and physical treatment in the sewage station to reach the discharge or reuse standard.

[0003] Chinese patent publication number CN217230471U, published on August 19, 2022, the utility model name is esterification water treatment system. The application discloses an esterification water treatment system. Alkali liquor is added to esterification water to reduce the pH value of esterification water and improve the efficiency of the stripping tower. The problem is that the alkali liquor is directly added to the esterification water container, which requires a stirring device, and the effect is poor and not accurate enough, with poor stability. The subsequent addition of esterification water requires re-adjustment of the pH value. UTILITY MODEL CONTENT

[0004] The purpose of the utility model is to provide an esterification water treatment device with a simplified structure, which can accurately control the acidity and alkalinity of wastewater, reduce the ethylene glycol that cannot be removed by the stripping tower, and reduce the chemical oxygen demand (COD) value. The device components are simplified and material-saving.

[0005] Another purpose of the utility model is to separate the esterification water tank, the alkali water tank, and the storage tank to improve the stability of adjusting the acidity and alkalinity of esterification water, and the subsequent addition of esterification water does not affect the operation of the device.

[0006] To achieve the above purpose, the utility model provides the following technical scheme:

[0007] An esterification water treatment device, an esterification water tank is connected to a storage tank through a first pipeline, and an alkali liquor tank is connected to the first pipeline through a second pipeline; a pH meter is arranged below the intersection of the first pipeline and the second pipeline; an automatic control module is arranged between the alkali liquor tank and the storage tank, and the automatic control module comprises a controller; the input end of the controller is connected to the pH meter, and the output end of the controller is connected to a metering pump on the second pipeline.

[0008] As a preferred, a control valve is arranged between the alkali liquor tank and the metering pump, and the metering pump is provided with a metering pump outlet pump close to one side of the first pipeline.

[0009] As a preferred, a flow meter and a pH meter are arranged on the first pipeline.

[0010] As preferred, the second pipeline is connected with the first pipeline through a metering pump outlet pump.

[0011] As preferred, a fourth pipeline is arranged below the esterification water tank, and the esterification water tank is connected with the first pipeline through the fourth pipeline.

[0012] As preferred, a delivery pump is arranged below the storage tank in the first pipeline.

[0013] As preferred, the storage tank is connected with the stripping tower through a third pipeline.

[0014] As preferred, the stripping tower is connected with the sewage treatment tank through a fifth pipeline.

[0015] The beneficial effects of the present application are: no need for stirring device, simple structure, saving materials. Mixing lye in the pipeline, stable and uniform effect, easy and accurate adjustment. The esterification water tank and the storage tank are separated, and subsequent addition of esterification water and lye will not affect the operation of the device, suitable for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The present application is a structural schematic diagram.

[0017] In the figure: 1, esterification water tank; 2, storage tank; 3, lye tank; 4, first pipeline; 5, second pipeline; 6, third pipeline; 7, stripping tower; 8, fourth pipeline; 9, fifth pipeline; 10, sewage treatment tank; 11, waste water pump; 12, flow meter; 13, pH meter; 14, control valve; 15, metering pump; 16, metering pump outlet valve; 17, waste water pump; 18, controller. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments.

[0019] As Figure 1The embodiment shown provides an esterification water treatment device, which comprises an esterification water tank 1, an input port of a first pipeline 4 is arranged at the bottom or middle-lower part of the esterification water tank 1, preferably at the bottom, and an output port of the first pipeline 4 is connected with an input port of a storage tank 2. Esterification water generated in an esterification reaction is stored in the esterification water tank 1 and is transported to the storage tank 2 through the first pipeline 4. When large-scale esterification water treatment is performed, esterification water can be continuously added to the esterification water tank 1 through a pipeline or other ways, which does not affect the operation of the device. In the embodiment, the esterification water tank 1 is arranged at a position higher than the storage tank 2, and the esterification water tank 1 can also be directly arranged above the storage tank 2. Gas bubbles are easily generated at the top of the esterification water tank 1, and the first pipeline 4 is arranged at the bottom of the esterification water tank 1, which facilitates emptying of the esterification water tank, guarantees the stability of esterification water transportation, facilitates control of the esterification water transportation speed, and is also beneficial to transportation of the esterification water through the gravity of the esterification water itself.

[0020] The embodiment also comprises a second pipeline 5, an input port of the second pipeline 5 is connected with an output port of a lye tank 3, and the output port is arranged at the middle-lower part or bottom of the lye tank 3. An output port of the second pipeline 5 is connected with the first pipeline 4 and is merged into the first pipeline 4, and lye of a fixed concentration is stored in the lye tank 3. The lye tank 3 is arranged below the esterification water tank 1, which facilitates connection of the second pipeline and the first pipeline 4, and the lye tank 3 can also be arranged at other positions as long as the space permits. In the embodiment, the height of the position of the lye tank 3 is basically level with the height of the position of the storage tank 2, the second pipeline 5 is provided with a control valve 14, a metering pump 15 and a metering pump outlet valve 16. The control valve 14, the metering pump 15 and the metering pump outlet valve 16 jointly act to realize precise control of the addition amount of lye. In other embodiments of the utility model, the lye tank 3 can be arranged at a position higher than the storage tank 2 and lower than the esterification water tank 1, which facilitates transportation through the gravity of the liquid. Similarly, when large-scale esterification water treatment is performed, lye can be added to the lye tank 3 at any time through different methods, which does not affect the operation of the device. The lye is transported to the first pipeline 4 through the second pipeline 5, is mixed with esterification water in the first pipeline 4, reduces the pH value of the esterification water, and then the mixed esterification water is transported to the storage tank 2 through the first pipeline 4 for storage.

[0021] The embodiment also comprises a stripping tower 7. The input of the third pipeline 6 is connected with the output of the storage tank 2, and the output is connected with the input of the stripping tower 7, so that the esterification water with reduced pH value is transported into the stripping tower 7. The stripping tower 7 separates part of the organic matter by means of stripping distillation according to the different boiling points of the organic matter, recovers part of the usable organic matter, and reduces the chemical oxygen demand COD value of the esterification water, which is an important method for treating the esterification water. Part of the raw material ethylene glycol exists in the esterification water, and the ethylene glycol is difficult to be separated out by the stripping tower 7 due to the high boiling point of the ethylene glycol, so that the COD value of the esterification water treated by the stripping tower 7 is too high. The ethylene glycol reacts with the diethyl ether to form 2-methyl-1,3-dioxolane in the stripping tower 7, and the 2-methyl-1,3-dioxolane can be separated out by the stripping tower 7 due to the low boiling point, so that part of the ethylene glycol can be removed in this way. However, the 2-methyl-1,3-dioxolane can be decomposed into ethylene glycol under acidic conditions, and the lower the pH value, the faster the decomposition speed of the 2-methyl-1,3-dioxolane.

[0022] Therefore, the embodiment adds lye into the esterification water, controls the acid-base degree of the wastewater, and inhibits the decomposition of 2-methyl-1,3-dioxolane to reduce the COD value of the esterification water. In the embodiment, the esterification water is pretreated before being transported into the stripping tower 7, the generation of ethylene glycol that cannot be treated by the stripping tower 7 is reduced by reducing the pH value of the esterification water, so that the treatment pressure of the stripping tower 7 is reduced, the efficiency is improved, the COD value of the esterification water is further reduced, and the emergency treatment capacity of the device is improved.

[0023] In another embodiment of the utility model, the first pipeline 4 does not rely on the self weight of the esterification water to transport the esterification water, but a delivery pump 11 is arranged on the first pipeline 4, so that the delivery speed of the esterification water can be controlled. In the embodiment, the esterification water tank 1 does not need to be arranged above or higher than the storage tank 2, and the space can be arranged freely. The end of the first pipeline 4 is also provided with a pH detector 13 near the position of the storage tank 2, the pH detector 13 is located after the intersection of the first pipeline 4 and the second pipeline 5, and is used for detecting the pH value of the esterification water after the lye is added.

[0024] The embodiment also comprises an automatic control module, and the automatic control module comprises a controller 18, a pH detector 13 and a metering pump 15. The controller 18 is the core part of the automatic control module, the input end of the controller 18 is connected with the pH detector 13, and the output end of the controller 18 is connected with the metering pump 15, which can be mechanical connection, electrical connection, communication connection and the like. The pH detector 13 detects the pH value of the esterification water after the lye is added, and then sends the pH value data to the controller 18. The controller 18 controls the metering pump 15 and the metering pump outlet valve 16 according to the pre-set pH value standard and the existing test pH value standard, controls the addition amount of the lye, and makes the pH value of the esterification water reach the predetermined standard.

[0025] Specifically, the pH detector 13 sends the current pH value data of the esterification water to the controller 18 at a certain time interval, the controller 18 detects that the pH value is small after receiving the data, and sends a control signal to the metering pump 15 to open the metering pump outlet valve 16 to start adding alkali liquor. The alkali liquor is transported from the alkali liquor tank 3 to the first pipeline 4 through the second pipeline 5 and mixed with the esterification water in the first pipeline 4. The mixing process is carried out in the pipeline. Since the space in the pipeline is small, and the transportation of the esterification water and the alkali liquor is controlled by the pump at a certain speed or pressure, the transportation speed is fast, and no stirring device is needed. The esterification water and the alkali liquor can be uniformly and quickly mixed in the pipeline. The pH detector 13 sends the pH value data in real time, and when the pH value decreases to a predetermined standard, the controller 18 closes the metering pump 15 and the metering pump outlet valve 16, or adjusts the power of the metering pump 15 to reduce the flow of the alkali liquor, so as to control the pH value in a certain range. The pH range is determined by comprehensively considering the cost of alkali liquor and other chemical reactions. Within this range, the esterification water has weak acidity, although it still causes 2-methyl-1,3-dioxolane to decompose into ethylene glycol and acetic acid, and cannot completely remove ethylene glycol, but the decomposition rate is low, and ethylene glycol can be removed as much as possible, the pressure and efficiency of the stripping tower 7 are reduced, and the chemical oxygen demand COD value of the esterification water is reduced as much as possible, and pollution is reduced. The process is automatically controlled by the controller 18, which greatly improves the timeliness, convenience and stability of adjustment.

[0026] In another embodiment of the present application, a liquid level sensing device is arranged in the storage tank 2, which can transmit the liquid level data to the controller 18 to prevent the esterification water from overflowing the storage tank 2 due to too fast transportation. Since it is difficult to avoid the fluctuation of the liquid level in the storage tank 2 during the transportation of the esterification water, the liquid level sensing device can ensure a certain amount of excess liquid to control the liquid level in the storage tank 2 and improve the emergency handling capacity.

[0027] In another embodiment of the utility model, on the basis of above embodiment, esterification water spray device is equipped on esterification water tank 1, esterification water spray device is connected with external esterification reaction device or esterification production equipment etc., and the product needed is produced in esterification reaction, and esterification wastewater is also continuously produced, can directly add esterification wastewater to esterification water tank 1 through esterification water spray device, esterification water tank 1 and storage tank 2 are connected through first pipeline 4, and conveying pump 11 and conveying valve are equipped on first pipeline 4, can control the conveying speed, thus the new esterification water produced in esterification reaction adds to esterification water tank 1 and does not influence the pH value of esterification water in storage tank 2, and storage tank 2 sends esterification water to stripping column 7 through third pipeline 6, does not influence the operation of stripping column 7.Alkaline tank 3 sends lye through second pipeline 5, and injection pump is equipped on second pipeline 5, and injection pump can evenly inject lye into first pipeline 4, controls the pH value of esterification water, and the effect is more stable through the injection pump injection lye, and subsequent stripping column 7 separation effect is better, and the efficiency is higher.

[0028] Further, the rate of esterification reaction or the rate of esterification water produced by esterification reaction can be used to adjust the rate of esterification water delivered by the first pipeline 4, so that the addition rate of esterification water in the esterification water tank 1 and the delivery rate of esterification water by the first pipeline 4 are basically consistent, achieving balance, or the addition rate is slightly faster than the delivery rate, keeping the esterification water level in the esterification water tank 1 stable, ensuring stable operation of the device, which can run for a long time. The lye delivery rate can also be measured by the metering pump 15 to deduce the delivery rate of esterification water, thereby inferring the operation rate of the esterification reaction. After the COD value of the esterification water is reduced by the device, useful substances can be recovered by technical means such as ethylene glycol recovery tower and acetaldehyde recovery tower. After the ethylene glycol is recovered, it can be input into the esterification reaction equipment to control the esterification reaction rate.

[0029] In another embodiment of the utility model, on the basis of above embodiment, esterification water tank 1 is also provided with fourth pipeline 8, the input end of fourth pipeline 8 is connected with the upper middle part of esterification water tank 1, as overflow pipe to limit the liquid level height of esterification water tank 1, keep the stability of liquid level, make the device can continue stable operation. The output end of fourth pipeline 8 is connected with first pipeline 4, and merges into first pipeline 4. The intersection of fourth pipeline 8 and first pipeline 4 is arranged before the intersection of second pipeline 5 and first pipeline 4, so that the overflow esterification water can still be added with lye, ensuring normal operation of the device. Because bubbles are easy to appear at the top of esterification water, which may affect the delivery of esterification water, first pipeline 1 should be used as much as possible. However, when the device is continuously running, fourth pipeline 8 should be opened to control the liquid level, which ensures that esterification water does not overflow and the bottom of esterification water is stable, preventing large fluctuations of esterification water in esterification water tank 1.

[0030] In another embodiment of the utility model, on the basis of above embodiment, stripping tower 7 is connected through fifth pipeline 9 and sewage treatment tank 10.The input end of fifth pipeline 9 is connected with the output end of stripping tower 7, and the output end of fifth pipeline 9 is connected with sewage treatment tank 10.After the esterification water is stripped and separated from low-boiling-point organic matter in stripping tower 7, the COD value of esterification water further drops, but since stripping tower 7 cannot separate high-boiling-point organic matter, the esterification water after being treated by stripping tower 7 still cannot reach the discharge or reuse standard, and needs to be delivered to sewage treatment tank 10 through fifth pipeline 9 to further be treated by biochemical and physical treatment to reach the discharge or reuse standard.For example, a neutralization tank can be used, after the esterification water enters sewage treatment tank 10, the pH value of esterification water is further adjusted to about 6.5-7.5, the COD value is adjusted, the temperature of esterification water is adjusted, a suitable environment for microorganisms is formed, which is conducive to the proliferation of microorganisms.In addition, other components of waste water can be neutralized, some organic components are added, through the action of microorganisms, precipitates are produced, and the precipitates are subsequently recovered by other technologies.Waste water pump 17 is arranged on fifth pipeline 9, which helps deliver the esterification water to sewage treatment tank 10, and can also control the delivery speed.

[0031] In summary, the esterification water treatment device provided by the utility model has simple structure, does not need a stirring device, can accurately control the acidity or alkalinity of waste water, reduces ethylene glycol that cannot be removed by stripping tower 7, improves the treatment efficiency of stripping tower, reduces the chemical oxygen demand COD value, and saves materials.Meanwhile, esterification water tank 1, storage tank 2 and lye tank 3 are separately arranged, esterification water and lye are mixed in first pipeline 4, the process is simple, the mixing is uniform, subsequent addition of esterification water does not affect the operation of the device, and there is no need to re-adjust the pH value, and the stability of adjusting the acidity or alkalinity of esterification water is improved.

[0032] Obviously, the above embodiments are only examples for clearly illustrating, and not limit the implementation. For ordinary skilled in the art, on the basis of the above description, other different forms of changes or variations can be made.The above embodiments need not and cannot be exhausted.The changes or variations derived from the above are still within the protection scope of the utility model.

Claims

1. An esterification water treatment device characterized in that, an esterification water tank (1) is connected with a storage tank (2) through a first pipeline (4), and a lye tank (3) is connected with the first pipeline (4) through a second pipeline (5); a pH meter (13) is arranged below the intersection of the first pipeline (4) and the second pipeline (5); an automatic control module is arranged between the lye tank (3) and the storage tank (2), and the automatic control module comprises a controller (18); the controller (18) is connected with the pH meter (13) at an input end and is connected with a metering pump (15) on the second pipeline (5) at an output end.

2. The esterification water treatment device according to claim 1, characterized by a control valve (14) is arranged between the lye tank (3) and the metering pump (15), and the metering pump (15) is provided with a metering pump outlet pump (16) on the side close to the first pipeline (4).

3. The esterification water treatment device according to claim 2, characterized by The second pipeline (5) is connected with the first pipeline (4) through the metering pump outlet pump (16).

4. The esterification water treatment device of claim 1, wherein A flow meter (12) is arranged below the intersection of the first pipeline (4) and the second pipeline (5), and the flow meter (12) is provided with the pH meter (13) between the flow meter (12) and the storage tank (2).

5. The esterification water treatment device of claim 1, wherein A fourth pipeline (8) is arranged below the esterification water tank (1), and the esterification water tank (1) is connected with the first pipeline (4) through the fourth pipeline (8).

6. The esterification water treatment device according to claim 1 or 4, characterized by A delivery pump (11) is arranged below the storage tank (2) on the first pipeline (4).

7. The esterification water treatment device of claim 1, wherein The storage tank (2) is connected with a stripping tower (7) through a third pipeline (6).

8. The esterification water treatment device of claim 7, wherein The stripping tower (7) is connected with a sewage treatment tank (10) through a fifth pipeline (9).

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