A methanol purification system for methanol wastewater

Abstract

The utility model relates to the technical field of purification device, specifically is a kind of methanol purification system of methanol wastewater.The utility model includes the separation tank for evaporating methanol in methanol wastewater, and the heating temperature of first heater installed on separation tank is higher than the boiling point of water in separation tank;It further includes the transition tank with internal medium temperature between the boiling point of methanol and the boiling point of water, and the liquid level below of transition tank is accessed by first exhaust pipe at the top of separation tank, and the top of transition tank is accessed by second exhaust pipe into condensing tank.The utility model optimizes heating mode, with high heating efficiency, and can effectively guarantee the recovery purity of methanol, overcome the defects that heating efficiency and purity are difficult to consider in prior art.

Description

Technical Field

[0001] This utility model relates to the field of purification equipment technology, specifically a methanol purification system for methanol wastewater. Background Technology

[0002] The wastewater discharged from the methanol-water separation tower of the low-temperature methanol washing unit contains methanol. The traditional treatment method for this wastewater is to directly discharge it into a sewage treatment plant for treatment or to distill and purify the methanol for recovery.

[0003] The main principle of methanol distillation purification and recovery is to utilize the fact that the boiling point of methanol is lower than that of water. The wastewater solution is heated to a temperature between the boiling points of methanol and water, causing the methanol to evaporate. The evaporated methanol vapor is then condensed into liquid methanol by a condensation mechanism for recovery.

[0004] In this purification method, the heating of methanol wastewater is crucial for methanol distillation purification. In practice, there are low-temperature heating methods using a water bath or a heater below the boiling point of water, and high-temperature heating methods using a temperature far above the boiling point of water. The advantage of low-temperature heating is that it effectively avoids local temperatures in the wastewater exceeding the boiling point of water, thus preventing excessive water vapor from entering the condensation unit along with methanol vapor, thereby improving purification purity; however, this method obviously has low heating efficiency for wastewater. The advantage of high-temperature heating is that it heats the wastewater efficiently; however, this method obviously causes local temperatures in the wastewater to become excessively high, leading to some water vapor entering the condensation unit along with methanol vapor. In summary, existing methanol wastewater distillation purification methods each have their advantages and disadvantages. Low-temperature heating can avoid excessive water vapor contamination and improve purity, but its heating efficiency is low; high-temperature heating has high efficiency, but it easily allows water vapor to enter the condensation unit along with methanol vapor, reducing purity, thus requiring a solution. Utility Model Content

[0005] In order to avoid and overcome the technical problems existing in the prior art, this utility model provides a methanol purification system for methanol wastewater. By optimizing the heating method, it can effectively ensure the purity of methanol recovery while having high heating efficiency, thus overcoming the defect of difficulty in balancing heating efficiency and purity in the prior art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A methanol purification system for methanol wastewater includes a separation tank for evaporating methanol from the methanol wastewater, wherein a first heater installed on the separation tank has a heating temperature higher than the boiling point of water inside the separation tank; it also includes a transition tank with an internal medium temperature between the boiling point of methanol and the boiling point of water, wherein the top of the separation tank is connected to the transition tank below the liquid level through a first exhaust pipe, and the top of the transition tank is connected to a condenser through a second exhaust pipe.

[0007] As a further aspect of this utility model: a second heater is installed inside the transition tank, and the heating temperature of the second heater is between the boiling point of methanol and the boiling point of water in the transition tank; a coil cooling assembly for cooling the medium inside the transition tank is also installed on the transition tank.

[0008] As a further embodiment of this utility model: the installation height of the transition tank is higher than that of the separation tank, the first exhaust pipe is inserted from the top of the transition tank below the liquid level inside the transition tank, the lower part of the transition tank is equipped with a return pipe that connects to the upper part of the separation tank, and a sixth valve is installed on the return pipe.

[0009] As a further improvement of this invention, a second liquid level sensor and a second temperature sensor are installed inside the transition tank.

[0010] As a further embodiment of this utility model: the separation tank is connected to the discharge pipe for discharging methanol wastewater, a first temperature sensor and a first liquid level sensor are installed inside the separation tank, a water outlet pipe is installed at the bottom of the separation tank, the water outlet pipe is connected to the separation tank through a first return pipe, an eleventh valve is installed on the first return pipe, and a water pump and a fourth valve are respectively installed on the water outlet pipe at the front and rear sides of the connection node with the first return pipe.

[0011] As a further embodiment of this utility model: the waste discharge pipe is connected to the separation tank through a wastewater purification pipe, a second valve is installed on the wastewater purification pipe, and a first valve is installed on the pipe behind the wastewater purification pipe on the waste discharge pipe.

[0012] As a further embodiment of this utility model: a third liquid level sensor is installed inside the condenser, a recovery pipe is installed at the bottom of the condenser, the body of the recovery pipe is connected to the condenser through a second return pipe, a twelfth valve is installed on the second return pipe, and an outlet pump and a tenth valve are respectively installed on the recovery pipe at the front and rear sides of the connection node with the second return pipe.

[0013] As a further improvement of this utility model: a pressure sensor is installed on the condenser, and a pressure relief pipe is also installed on the top of the condenser. An eighth valve is installed on the pressure relief pipe, and the end of the pressure relief pipe is connected to a torch.

[0014] As a further improvement of this utility model, a condenser is installed on the condenser tank.

[0015] As a further improvement of this utility model, a fifth valve and a seventh valve are respectively installed on the first exhaust pipe and the second exhaust pipe.

[0016] Compared with the prior art, the beneficial effects of this utility model are: 1. This application includes a transition tank between the separation tank and the condenser. The first heater installed on the separation tank has a heating temperature higher than the boiling point of water inside the separation tank, used for rapid heating of methanol wastewater. Compared to slow heating below the boiling point of water, this effectively ensures the heating efficiency of the wastewater. Since the temperature of the medium inside the transition tank is between the boiling points of methanol and water, most of the water vapor is cooled and mixed with the medium inside the transition tank after passing through it. The methanol vapor, however, continues to pass through the medium inside the transition tank and enters the condenser through the second exhaust pipe at the top of the transition tank, where it is liquefied into liquid methanol and stored. This allows this application to achieve high heating efficiency while effectively ensuring the purity of recovered methanol, overcoming the shortcomings of existing technologies where heating efficiency and purity are difficult to balance.

[0017] 2. A second heater is installed inside the transition tank, and the heating temperature of the second heater is between the boiling point of methanol and the boiling point of water in the transition tank, so as to avoid the local temperature of the medium being too high and generating water vapor during the heating process; a coil cooling assembly for cooling the medium inside the transition tank is also installed on the transition tank, thereby realizing the temperature regulation inside the transition tank and keeping the temperature of the medium inside the transition tank within the required temperature range.

[0018] 3. The transition tank is installed at a higher height than the separator. The first vent pipe extends from the top of the transition tank below the liquid level inside. A return pipe connecting to the upper part of the separator is installed at the bottom of the transition tank, and a sixth valve is installed on the return pipe. If the transition tank absorbs too much water vapor, causing the liquid level to rise significantly, the medium in the transition tank can be returned to the separator under gravity by opening the sixth valve on the return pipe, eliminating the need for a power pump to extract the excess medium from the transition tank.

[0019] 4. A water outlet pipe is installed at the bottom of the separator. The water outlet pipe connects to the separator via a first return pipe. An eleventh valve is installed on the first return pipe. A water pump and a fourth valve are installed on the water outlet pipe before and after the connection point with the first return pipe, respectively. By closing the fourth valve and opening the eleventh valve and the water pump, the methanol wastewater in the separator can be discharged through the water outlet pipe and then returned to the separator through the first return pipe, thus agitating the methanol wastewater and improving the uniformity of its heating.

[0020] 5. A second reflux pipe is installed on the methanol recovery pipe in the condenser to circulate the methanol back into the condenser. By opening the tenth valve and the outlet pump, and closing the twelfth valve, the methanol liquid in the condenser is turbulent, improving the temperature uniformity in the condenser.

[0021] 6. A pressure sensor is installed on the condenser to monitor the pressure inside. A pressure relief pipe is also installed on the top of the condenser, with an eighth valve on it. The end of the pressure relief pipe is connected to a torch. When the pressure sensor detects that the pressure inside the condenser is too high, the eighth valve can be opened by the controller or manually, thus releasing the pressure inside the condenser and ensuring safety during the purification process. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of this utility model.

[0023] In the diagram: 10. Wastewater purification pipe; 20. Waste discharge pipe; 30. Separation tank; 31. First heater; 32. First temperature sensor; 33. First liquid level sensor; 40. Transition tank; 41. First exhaust pipe; 42. Return pipe; 43. Second exhaust pipe; 44. Second heater; 45. Coil cooling assembly; 46. Second temperature sensor; 47. Second liquid level sensor; 50. Water outlet pipe; 51. Water outlet pump; 60. First return pipe; 70. Condensate tank; 71. Pressure sensor; 72. Pressure relief pipe; 73. Third liquid level sensor; 80. Recovery pipe; 81. Liquid outlet pump; 90. Second return pipe; a. First valve; b. Second valve; c. Third valve; d. Fourth valve; e. Fifth valve; f. Sixth valve; g. Seventh valve; h. Eighth valve; i. Ninth valve; j. Tenth valve; k. Eleventh valve; m. Twelfth valve. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] For ease of understanding, the specific structure and working method of this utility model are further described below with reference to the accompanying drawings: The specific structure of this utility model is as follows: Figure 1 As shown, its main structure includes a separation tank 30 for evaporating methanol from methanol wastewater, a transition tank 40 for absorbing water from the mixed vapor of methanol and water generated in the separation tank 30, and a condenser tank 70 for condensing methanol vapor in the transition tank 40 into methanol.

[0026] Specifically, such as Figure 1As shown, the heating temperature of the first heater 31 installed on the separator 30 is higher than the boiling point of water inside the separator 30, which is used for rapid heating of methanol wastewater. Compared with slow heating below the boiling point of water, this effectively ensures the heating efficiency of the wastewater. Since the top of the separator 30 is connected to the transition tank 40 below the liquid level through the first exhaust pipe 41, the mild vapor of methanol and water generated in the separator 30 will enter the transition tank 40 through the first exhaust pipe 41. Since the temperature of the medium (preferably a simple aqueous solution) inside the transition tank 40 is between the boiling point of methanol and the boiling point of water, most of the water vapor will be cooled and mixed with the medium inside the transition tank 40 after passing through it. The methanol vapor will still pass through the medium inside the transition tank 40 and enter the condenser 70 through the second exhaust pipe 43 at the top of the transition tank 40, and then liquefy into methanol liquid and store it in the condenser 70. This allows the present application to have high heating efficiency while effectively ensuring the purity of methanol recovery, overcoming the defect of difficulty in balancing heating efficiency and purity in the prior art.

[0027] Based on the above, such as Figure 1 As shown, a second heater 44 is installed inside the transition tank 40, and the heating temperature of the second heater 44 is between the boiling point of methanol and the boiling point of water in the transition tank 40, to avoid the local temperature of the medium becoming too high and generating water vapor during the heating process. A coil cooling assembly 45 is also installed on the transition tank 40 to cool the medium inside, thereby achieving temperature regulation within the transition tank 40 and maintaining the temperature of the medium inside the transition tank 40 within the required temperature range. Of course, the medium inside the transition tank 40 can be self-heated by the second heater 44 inside the transition tank 40. In actual implementation, not only can the second heater 44 prevent the temperature inside the transition tank 40 from consistently falling below the boiling point of methanol, but it can also directly heat the medium inside the transition tank 40, thus eliminating the need to heat the medium externally before transferring it to the transition tank 40. Of course, if the medium is heated directly using the second heater 44, the initial amount of medium in the transition tank 40 does not need to be too large. The mixed steam of methanol and water absorbed by the second heater 44 and the transition tank 40 can rapidly raise the temperature, and with the long-term operation of this application, the mixed steam can also raise the liquid level of the medium in the transition tank 40. Of course, since the high-temperature mixed steam of methanol and water is continuously introduced into the transition tank 40 for a long time during the long-term operation of this application, the medium temperature in the transition tank 40 will be high. The coil cooling assembly 45 can cool down the medium in the transition tank 40 when the medium temperature is high, so that the medium in the transition tank 40 is as close as possible to the boiling point of methanol. The coil cooling assembly 45 can be a traditional coil-type water-cooled pipe, which can be connected to a cooling tower or compressor structure to cool the internal medium.

[0028] Based on the above, the installation height of the transition tank 40 is higher than that of the separation tank 30. The first vent pipe 41 is inserted from the top of the transition tank 40 below the liquid level inside the transition tank 40. A return pipe 42 connecting to the upper part of the separation tank 30 is installed at the lower part of the transition tank 40, and a sixth valve f is installed on the return pipe 42. When the liquid level rises significantly due to excessive water vapor absorption in the transition tank 40, the medium in the transition tank 40 can be returned to the separation tank 30 under gravity by opening the sixth valve f on the return pipe 42, without the need for a power pump to extract the excess medium from the transition tank 40.

[0029] In addition, such as Figure 1 As shown, a second liquid level sensor 47 and a second temperature sensor 46 are installed inside the transition tank 40 to monitor the liquid level and temperature inside the transition tank 40. In actual implementation, the staff can manually adjust the liquid level and temperature inside the transition tank 40 according to the monitored liquid level and temperature information; or the liquid level and temperature can be automatically controlled by a controller. The control method of this controller is a conventional control method in the prior art, which will not be described in detail here.

[0030] Based on the above, such as Figure 1 As shown, the separator 30 is connected to the discharge pipe 20 for methanol wastewater, enabling automatic liquid intake of methanol wastewater into the separator 30. A first temperature sensor 32 and a first liquid level sensor 33 are installed inside the separator 30 to monitor the temperature and liquid level, respectively. Furthermore, a water outlet pipe 50 is installed at the bottom of the separator 30. The water outlet pipe 50 is connected to the separator 30 via a first return pipe 60. An eleventh valve k is installed on the first return pipe 60. A water outlet pump 51 and a fourth valve d are installed on the water outlet pipe 50 before and after the connection point with the first return pipe 60, respectively. In actual implementation, if it is necessary to agitate the methanol wastewater in the separator 30 to improve heating uniformity, the fourth valve d can be closed, and the eleventh valve k and the water outlet pump 51 can be opened. This allows the methanol wastewater in the separator 30 to be discharged through the water outlet pipe 50 and then returned to the separator 30 through the first return pipe 60, thus agitating the methanol wastewater. If it is necessary to discharge the solution after evaporation in the separator 30, the fourth valve d can be opened. If it is necessary to increase the discharge speed, the water pump 51 can be turned on and the eleventh valve k can be closed, so that the solution can be discharged out through the water outlet pipe 50.

[0031] It is worth mentioning that, in actual implementation, a third valve c can be installed on the outlet pipe 50 at the inlet of the outlet pump 51. In case of a malfunction of the outlet pump 51, the third valve c can be closed for maintenance.

[0032] Furthermore, such as Figure 1As shown, the waste discharge pipe 20 is connected to the separation tank 30 via the wastewater purification pipe 10. A second valve b is installed on the wastewater purification pipe 10, and a first valve a is installed on the waste discharge pipe 20 on the pipe downstream of the wastewater purification pipe 10. By closing the second valve b and opening the first valve a, the waste discharge pipe 20 retains the traditional discharge path to wastewater treatment; while opening the second valve b and closing the first valve a, it enters the methanol purification working path of this application, realizing a dual selection of wastewater treatment path and methanol purification path.

[0033] Based on the above, such as Figure 1 As shown, a third liquid level sensor 73 is installed inside the condenser 70 to monitor the liquid level inside the condenser 70. A recovery pipe 80 is installed at the bottom of the condenser 70, and the pipe body of the recovery pipe 80 is connected to the condenser 70 through a second return pipe 90. A twelfth valve m is installed on the second return pipe 90. A liquid discharge pump 81 and a tenth valve j are installed on the recovery pipe 80 before and after the connection node with the second return pipe 90, respectively. Similar to the design of the water outlet pipe 50 on the separator 30, this application sets a second return pipe 90 on the recovery pipe 80 for recovering methanol in the condenser 70, which can circulate into the condenser 70. In implementation, by opening the tenth valve j and the liquid discharge pump 81 and closing the twelfth valve m, the methanol liquid in the condenser 70 is turbulent, improving the temperature uniformity in the condenser 70. By opening the twelfth valve m and the liquid discharge pump 81 and closing the tenth valve j, the purified methanol liquid in the condenser 70 can be discharged and collected. Similarly, in actual implementation, a ninth valve i can be installed on the pipeline located at the inlet of the discharge pump 81 on the recovery pipe 80. By closing the ninth valve i, the discharge pump 81 can be inspected and repaired.

[0034] Furthermore, a pressure sensor 71 is installed on the condenser 70 to monitor the pressure inside the condenser 70. A pressure relief pipe 72 is also installed on the top of the condenser 70, and an eighth valve h is installed on the pressure relief pipe 72. The end of the pressure relief pipe 72 is connected to a torch. When the pressure sensor 71 detects that the pressure inside the condenser 70 is too high, the eighth valve h can be opened by the controller or manually, thereby relieving the pressure inside the condenser 70 and ensuring safety during the purification process.

[0035] Based on the above, such as Figure 1 As shown, a condenser is installed on the condenser tank 70 to reduce its temperature. In practice, the condenser can be a water-cooled coil structure or an air conditioning condenser structure to achieve the desired cooling effect on the condenser tank 70. This method is more effective at condensing vapor into liquid than using a self-heating tank structure with good heat dissipation (such as a copper or aluminum tank with added heat dissipation fins).

[0036] Based on the above, such as Figure 1As shown, the first exhaust pipe 41 and the second exhaust pipe 43 are respectively equipped with a fifth valve e and a seventh valve g, so that the passage of the first exhaust pipe 41 and the second exhaust pipe 43 can be controlled and closed independently, so as to carry out independent maintenance operations on the separator 30, the transition tank 40 and the condenser 70.

[0037] Of course, those skilled in the art will recognize that this invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0038] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0039] The technologies, shapes, and structures not described in detail in this utility model are all known technologies.

Claims

1. A methanol purification system for methanol wastewater, characterized in that, It includes a separator (30) for evaporating methanol from methanol wastewater, and the heating temperature of the first heater (31) installed on the separator (30) is higher than the boiling point of the water in the separator (30); it also includes a transition tank (40) with an internal medium temperature between the boiling point of methanol and the boiling point of water, the top of the separator (30) is connected to the transition tank (40) below the liquid level through the first exhaust pipe (41), and the top of the transition tank (40) is connected to the condenser (70) through the second exhaust pipe (43).

2. The methanol purification system for methanol wastewater according to claim 1, characterized in that, The transition tank (40) is equipped with a second heater (44), and the heating temperature of the second heater (44) is between the boiling point of methanol and the boiling point of water in the transition tank (40); the transition tank (40) is also equipped with a coil cooling assembly (45) for cooling the medium in the transition tank (40).

3. The methanol purification system for methanol wastewater according to claim 2, characterized in that, The installation height of the transition tank (40) is higher than that of the separation tank (30). The first exhaust pipe (41) is inserted from the top of the transition tank (40) below the liquid level in the transition tank (40). The lower part of the transition tank (40) is equipped with a return pipe (42) that connects to the upper part of the separation tank (30), and a sixth valve (f) is installed on the return pipe (42).

4. The methanol purification system for methanol wastewater according to claim 3, characterized in that, The transition tank (40) is equipped with a second liquid level sensor (47) and a second temperature sensor (46).

5. A methanol purification system for methanol wastewater according to any one of claims 1-4, characterized in that, The separator (30) is connected to the discharge pipe (20) for discharging methanol wastewater. A first temperature sensor (32) and a first liquid level sensor (33) are installed inside the separator (30). A water outlet pipe (50) is installed at the bottom of the separator (30). The body of the water outlet pipe (50) is connected to the separator (30) through a first return pipe (60). An eleventh valve (k) is installed on the first return pipe (60). A water pump (51) and a fourth valve (d) are installed on the water outlet pipe (50) at the front and rear sides of the connection node with the first return pipe (60), respectively.

6. The methanol purification system for methanol wastewater according to claim 5, characterized in that, The waste discharge pipe (20) is connected to the separation tank (30) via the wastewater purification pipe (10). A second valve (b) is installed on the wastewater purification pipe (10), and a first valve (a) is installed on the pipe behind the wastewater purification pipe (10) on the waste discharge pipe (20).

7. A methanol purification system for methanol wastewater according to any one of claims 1-4, characterized in that, The condenser (70) is equipped with a third liquid level sensor (73). A recovery pipe (80) is installed at the bottom of the condenser (70). The body of the recovery pipe (80) is connected to the condenser (70) through a second return pipe (90). A twelfth valve (m) is installed on the second return pipe (90). A liquid discharge pump (81) and a tenth valve (j) are installed on the recovery pipe (80) at the front and rear sides of the connection node with the second return pipe (90), respectively.

8. A methanol purification system for methanol wastewater according to any one of claims 1-4, characterized in that, A pressure sensor (71) is installed on the condenser (70), and a pressure relief pipe (72) is also installed on the top of the condenser (70). An eighth valve (h) is installed on the pressure relief pipe (72), and the end of the pressure relief pipe (72) is connected to a torch.

9. A methanol purification system for methanol wastewater according to any one of claims 1-4, characterized in that, A condenser is installed on the condenser tank (70).

10. A methanol purification system for methanol wastewater according to any one of claims 1-4, characterized in that, The first exhaust pipe (41) and the second exhaust pipe (43) are respectively equipped with a fifth valve (e) and a seventh valve (g).

Images