Waste heat utilization equipment for methanol-to-olefin device

Abstract

The utility model relates to the technical field of methanol-to-olefin devices, in particular to waste heat utilization equipment for a methanol-to-olefin device, which comprises a high-pressure component, a low-pressure component and a condensate collecting bag, the high-pressure component comprises a high-pressure condensate tank and a first debutanizer reboiler, and an outlet of the high-pressure condensate tank is fixedly connected with an inlet of the first debutanizer reboiler; an outlet of the first debutanizer reboiler is fixedly connected with inlets of the debutanizer and the condensate collecting bag; the low-pressure assembly comprises a first water pump, a first dethanizing column reboiler and a medium-pressure condensate tank, an inlet of the first water pump is fixedly connected with an outlet of the medium-pressure condensate tank, an outlet of the first water pump is fixedly connected with an inlet of the first dethanizing column reboiler, and an outlet of the first dethanizing column reboiler is fixedly connected with an inlet of the dethanizing column and an inlet of the condensate collecting bag. According to the waste heat utilization equipment for the methanol-to-olefin device, the steam consumption and the discharge amount of high-pressure condensate and medium-pressure condensate are reduced.

Description

Technical Field

[0001] This utility model relates to the technical field of methanol-to-olefins (MTO) equipment, specifically to a waste heat recovery device for a MTO equipment. Background Technology

[0002] The MTO (methanol to olefins) unit produces 50 tons of medium-pressure condensate at 115°C and 1.0 MPa per hour and 7 tons of high-pressure condensate at 140°C and 4.0 MPa per hour, respectively. These condensates come from the medium-pressure condensate produced by the methanol preheating heat exchanger, the product water stripping tower reboiler, and the oxide stripping tower reboiler, as well as the high-pressure condensate produced by the methanol superheating heat exchanger.

[0003] Currently, the medium-pressure and high-pressure condensates generated during the operation of MTO units need to be cooled by air coolers and circulating water heat exchangers before being discharged. This increases the load on the circulating water system, and the discharged condensates are still at relatively high temperatures, with heat being directly dissipated into the environment, resulting in energy waste and environmental pollution. Furthermore, the butane and ethane removal towers in the olefin separation unit consume large amounts of low-pressure steam as a heat source; specifically, the steam consumption of the butane removal tower reboiler is 1100 kg / h, and the steam consumption of the ethane removal tower reboiler is 5900 kg / h. Because the waste heat from the medium-pressure and high-pressure condensates is not utilized, the steam consumption of the olefin separation unit remains high, ultimately leading to high overall energy consumption and operating costs for the MTO unit, indirectly increasing carbon emissions. The failure to integrate the waste heat from the medium-pressure and high-pressure condensates with the heat demand of the olefin separation unit prevents efficient energy utilization. Therefore, how to recover and utilize the waste heat from the medium-pressure and high-pressure condensates is crucial for reducing the energy consumption and operating costs of the MTO unit. Utility Model Content

[0004] To address the technical problem of directly discharging medium-pressure and high-pressure condensate generated during the operation of MTO units, this invention provides a waste heat recovery device for methanol-to-olefins (MTO) units. The waste heat from the high-pressure and medium-pressure condensate is utilized by the reboilers of the first butane removal tower and the first ethane removal tower in the olefin separation unit. This reduces steam consumption and the amount of high-pressure and medium-pressure condensate discharged, achieving efficient cascade utilization of waste heat and energy, lowering the overall energy consumption and operating costs of the MTO unit, and reducing thermal pollution caused by condensate discharge.

[0005] This utility model provides a waste heat recovery device for a methanol-to-olefins (MTO) plant, comprising a high-pressure component, a low-pressure component, and a condensate collection bag. The high-pressure component includes a high-pressure condensate tank and a first butane de-boiler. The outlet of the high-pressure condensate tank is fixedly connected to the inlet of the first butane de-boiler, and the outlet of the first butane de-boiler is fixedly connected to the inlet of the butane de-boiler and the condensate collection bag. The low-pressure component includes a first water pump, a first ethane de-boiler, and a medium-pressure condensate tank. The inlet of the first water pump is fixedly connected to the outlet of the medium-pressure condensate tank, and the outlet of the first water pump is fixedly connected to the inlet of the first ethane de-boiler. The outlet of the first ethane de-boiler is fixedly connected to the inlet of the ethane de-boiler and the condensate collection bag. High-pressure condensate is fed to the reboiler of the first butane dehydrogenator. After heat exchange, the material enters the butane dehydrogenator, and the low-pressure condensate after heat exchange is stored in a condensate collection bag. Medium-pressure condensate is fed to the reboiler of the first ethane dehydrogenator. After heat exchange, the material enters the ethane dehydrogenator, and the low-pressure condensate after heat exchange is stored in a condensate collection bag.

[0006] Furthermore, the inlet of the first butane de-butane tower reboiler is fixedly connected to the outlet of the high-pressure condensate tank via a first pipe, and a first valve is installed on the first pipe. The outlet of the first butane de-butane tower reboiler is fixedly connected to the inlet of the butane de-butane tower via a second pipe. The outlet of the first butane de-butane tower reboiler is fixedly connected to the inlet of the condensate collection bag via a third pipe, and a third valve is installed on the third pipe.

[0007] Furthermore, the first pipeline is fixedly connected to the third pipeline via a fourth pipeline. A second valve is installed on the first pipeline, and the connection point between the fourth pipeline and the first pipeline is located between the first valve and the second valve. The connection point between the fourth pipeline and the third pipeline is located below the third valve. A fourth valve is installed on the fourth pipeline. When the first and second valves are opened and the fourth valve is closed, the high-pressure condensate in the high-pressure condensate tank enters the bottom of the reboiler of the first butane removal tower through the first pipeline and exchanges heat counter-currently with the material.

[0008] Furthermore, it also includes a second debutanizer reboiler. The inlet of the second debutanizer reboiler is used to introduce steam, and the outlet of the second debutanizer reboiler is fixedly connected to the second pipe via a fifth pipe. Low-pressure steam is introduced into the second debutanizer reboiler, and the low-pressure steam exchanges heat counterclockwise with the material entering the second debutanizer reboiler. The material after heat exchange enters the debutanizer through the fifth pipe and the second pipe.

[0009] Furthermore, the inlet of the first water pump is fixedly connected to the outlet of the medium-pressure condensate tank via a sixth pipe, and the outlet of the first water pump is fixedly connected to the inlet of the first deethaner reboiler via a seventh pipe, the seventh pipe being equipped with a fifth valve. The outlet of the first deethaner reboiler is fixedly connected to the inlet of the deethaner via an eighth pipe, and the outlet of the first deethaner reboiler is fixedly connected to the inlet of the condensate collection bag via a ninth pipe, the ninth pipe being equipped with a sixth valve.

[0010] Furthermore, the seventh pipe is fixedly connected to the ninth pipe via the tenth pipe. The connection point between the tenth and seventh pipes is located below the fifth valve, and the connection point between the tenth and ninth pipes is located below the sixth valve. The seventh valve is installed on the tenth pipe. When the seventh valve is opened and the fifth valve is closed, the medium-pressure condensate in the medium-pressure condensate tank enters the condensate collection bag for storage through the sixth, tenth, and ninth pipes.

[0011] Furthermore, it also includes a second deethanizer reboiler. The inlet of the second deethanizer reboiler is used to introduce steam, and the outlet of the second deethanizer reboiler is fixedly connected to the eighth pipe via the eleventh pipe. Low-pressure steam is introduced into the second deethanizer reboiler, and the low-pressure steam exchanges heat counterclockwise with the material entering the second deethanizer reboiler. The material after heat exchange enters the deethanizer through the eleventh pipe and the eighth pipe.

[0012] Furthermore, the outlet of the condensate collection bag is fixedly connected to the inlet of the second water pump, and the outlet of the second water pump is fixedly connected to the circulating water heat exchanger. When the second water pump starts, the low-pressure condensate in the condensate collection bag, after heat exchange, is finally discharged after exchanging heat with the circulating water in the circulating water heat exchanger.

[0013] Furthermore, the methanol-to-olefins unit includes a methanol superheater heat exchanger, which is fixedly connected to the inlet of a high-pressure condensate tank. The high-pressure condensate enters the high-pressure condensate tank for storage.

[0014] Furthermore, the methanol-to-olefins unit includes an air cooler, which is fixedly connected to the inlet of a medium-pressure condensate tank. The medium-pressure condensate, after heat exchange in the air cooler, enters the medium-pressure condensate tank for storage.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The waste heat recovery device for the methanol-to-olefins (MTO) unit of this invention utilizes the waste heat of the high-pressure condensate and medium-pressure condensate in the first butane removal tower reboiler and the first ethane removal tower reboiler of the olefin separation unit. This reduces steam consumption and the discharge of high-pressure and medium-pressure condensate, achieving efficient cascade utilization of waste heat and energy, reducing the overall energy consumption and operating cost of the MTO unit, thereby reducing carbon emissions, and also reducing thermal pollution caused by condensate discharge. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a waste heat recovery device for a methanol-to-olefins plant according to this utility model;

[0018] The numbers in the attached diagram are:

[0019] 1. High-pressure condensate tank; 2. First butane stripper reboiler; 21. First pipeline; 22. Second pipeline; 23. Third pipeline; 24. Fourth pipeline; 3. Second butane stripper reboiler; 31. Fifth pipeline; 4. Medium-pressure condensate tank; 41. Sixth pipeline; 42. Air cooler; 5. First water pump; 6. First ethane stripper reboiler; 61. Seventh pipeline; 62. Eighth pipeline; 63. Ninth pipeline; 64. Tenth pipeline; 7. Second ethane stripper reboiler; 71. Eleventh pipeline; 8. Second water pump; 81. Circulating water heat exchanger; 9. Condensate collection bag. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1 As shown, a waste heat recovery device for a methanol-to-olefins (MTO) plant includes a high-pressure component, a low-pressure component, and a condensate collection bag 9. The high-pressure component includes a high-pressure condensate tank 1 and a first butane deboiler 2. The outlet of the high-pressure condensate tank 1 is fixedly connected to the inlet of the first butane deboiler 2, and the outlet of the first butane deboiler 2 is fixedly connected to the inlet of the butane deboiler and the condensate collection bag 9. The low-pressure component includes a first water pump 5, a first ethane deboiler 6, and a medium-pressure condensate tank 4. The inlet of the first water pump 5 is fixedly connected to the outlet of the medium-pressure condensate tank 4, and the outlet of the first water pump 5 is fixedly connected to the inlet of the first ethane deboiler 6. The outlet of the first ethane deboiler 6 is fixedly connected to the inlet of the ethane deboiler and the condensate collection bag 9.

[0022] High-pressure condensate is stored in high-pressure condensate tank 1 and transported to the first butane de-butanizer reboiler 2. The high-pressure condensate serves as a heat source, replacing part of the low-pressure steam. Preferably, to increase heat exchange efficiency and residence time, the high-pressure condensate enters the first butane de-butanizer reboiler 2 through the bottom and exchanges heat counter-currently with the material in the butane de-butanizer. The heat from the high-pressure condensate is transferred to the butane de-butanizer through the first butane de-butanizer reboiler 2, and is ultimately used for heating and separating the material within the butane de-butanizer. Specifically, the low-pressure steam consumption of the first butane de-butanizer reboiler 2 is reduced from 1100 kg / h to 600 kg / h, saving 500 kg / h of steam per hour. Annual steam savings: 500 kg / h × 24h / d (24 hours per day) × 330d / y (330 working days per year) = 3960 tons / year; Annual economic benefit: Based on steam prices, the annual efficiency increase is approximately 780,000 yuan. Furthermore, the material after heat exchange enters the butane removal tower, and the low-pressure condensate after heat exchange enters the condensate collection bag 9 for storage.

[0023] Medium-pressure condensate is stored in the medium-pressure condensate tank 4. The first pump, once activated, delivers the medium-pressure condensate to the first deethanizer reboiler 6. The medium-pressure condensate serves as a heat source, replacing part of the low-pressure steam. Preferably, to increase heat exchange efficiency and residence time, the medium-pressure condensate enters the first deethanizer reboiler 6 through the bottom and exchanges heat counter-currently with the material (deethanizer). The heat from the medium-pressure condensate is transferred to the deethanizer through the first deethanizer reboiler 6, ultimately used for heating and separating the material within the deethanizer. The low-pressure steam consumption of the first deethanizer reboiler 6 is reduced from 5900 kg / h to 4900 kg / h, saving 1000 kg / h of steam per hour. Annual steam savings: 1000 kg / h × 24 h / d × 330 d / y = 7920 tons / year; Annual economic benefit: calculated based on steam prices, the annual efficiency improvement is at least 1.56 million yuan. The material after heat exchange enters the de-ethanizer, and the low-pressure condensate after heat exchange enters the condensate collection bag 9 for storage. By recovering and utilizing the waste heat of the medium-pressure and high-pressure condensates, the total annual efficiency improvement is 2.34 million yuan, thus significantly reducing the operating cost of the MTO unit.

[0024] In this embodiment, the waste heat utilization equipment utilizes the waste heat of the high-pressure condensate and the medium-pressure condensate in the first debutanizer reboiler 2 and the first deethanizer reboiler 6 of the olefin separation unit. This reduces steam consumption and the discharge of high-pressure and medium-pressure condensate, achieving efficient cascade utilization of waste heat and energy, reducing the overall energy consumption and operating cost of the MTO unit, thereby reducing carbon emissions, and also reducing thermal pollution caused by condensate discharge.

[0025] In one possible implementation, the inlet of the first butane debutane reboiler 2 is fixedly connected to the outlet of the high-pressure condensate tank 1 via a first pipe 21, and a first valve is installed on the first pipe 21. The outlet of the first butane debutane reboiler 2 is fixedly connected to the inlet of the butane debutane tower via a second pipe 22, and the outlet of the first butane debutane reboiler 2 is fixedly connected to the inlet of the condensate collection bag 9 via a third pipe 23, and a third valve is installed on the third pipe 23. When the first valve is opened, the high-pressure condensate in the high-pressure condensate tank 1 enters the bottom of the first butane debutane reboiler 2 through the first pipe 21 and exchanges heat counterclockwise with the material entering the second butane debutane reboiler 3 (butane debutane tower). The material after heat exchange enters the butane debutane tower through the second pipe 22. The heat from the high-pressure condensate is transferred to the butane debutane tower through the first butane debutane reboiler 2, and is ultimately used for heating and separating the material inside the butane debutane tower. When the third valve is opened, the low-pressure condensate after heat exchange enters the condensate collection bag 9 through the third pipe 23 for storage.

[0026] In one possible implementation, the first pipe 21 is fixedly connected to the third pipe 23 via a fourth pipe 24. A second valve is installed on the first pipe 21, and the connection point between the fourth pipe 24 and the first pipe 21 is located between the first valve and the second valve. The connection point between the fourth pipe 24 and the third pipe 23 is located below the third valve. A fourth valve is installed on the fourth pipe 24. When the first and second valves are opened and the fourth valve is closed, the high-pressure condensate in the high-pressure condensate tank 1 enters the bottom of the first butane de-butanizer reboiler 2 through the first pipe 21 and exchanges heat counter-currently with the material.

[0027] After the excess high-pressure condensate in the high-pressure condensate tank 1 is no longer used, the first valve and the fourth valve are opened and the second valve is closed. The high-pressure condensate in the high-pressure condensate tank 1 also enters the condensate collection bag 9 for storage through the first pipe 21, the fourth pipe 24 and the third pipe 23.

[0028] As one possible implementation, a second butane debutane tower reboiler 3 is also included. The inlet of the second butane debutane tower reboiler 3 is used to introduce steam, and the outlet of the second butane debutane tower reboiler 3 is fixedly connected to the second pipe 22 via a fifth pipe 31. The second butane debutane tower reboiler 3 is a spare unit and adopts a steam heating mode to ensure the normal operation of the butane debutane tower when the high-pressure condensate supply is insufficient.

[0029] Low-pressure steam is introduced into the reboiler 3 of the second butane de-butanizer. The low-pressure steam exchanges heat counter-currently with the material entering the reboiler 3. The material after heat exchange enters the butane de-butanizer through the fifth pipe 31 and the second pipe 22. The heat from the low-pressure steam is used for heating and separation of the material inside the butane de-butanizer. The low-pressure condensate after heat exchange is discharged through the condensate pipeline located at the outlet of the reboiler 3 of the second butane de-butanizer.

[0030] In one possible implementation, the inlet of the first water pump 5 is fixedly connected to the outlet of the medium-pressure condensate tank 4 via a sixth pipe 41, the outlet of the first water pump 5 is fixedly connected to the inlet of the first deethaner reboiler 6 via a seventh pipe 61, and a fifth valve is provided on the seventh pipe 61. The outlet of the first deethaner reboiler 6 is fixedly connected to the inlet of the deethaner via an eighth pipe 62, and the outlet of the first deethaner reboiler 6 is fixedly connected to the inlet of the condensate collection bag 9 via a ninth pipe 63, and a sixth valve is provided on the ninth pipe 63.

[0031] The first water pump 5 starts, and the fifth valve is opened. The medium-pressure condensate in the medium-pressure condensate tank 4 enters the bottom of the first deethanizer reboiler 6 through the sixth pipe 41 and the seventh pipe 61, and exchanges heat counterclockwise with the material entering the first deethanizer reboiler 6 (deethanizer). The material after heat exchange enters the deethanizer through the eighth pipe 62. The heat of the medium-pressure condensate is transferred to the deethanizer through the first deethanizer reboiler 6, and is finally used for heating and separation of the material in the deethanizer. The sixth valve is opened, and the low-pressure condensate after heat exchange enters the condensate collection bag 9 through the ninth pipe 63 for storage.

[0032] Generally, the first butane de-butane reboiler 2 and the first ethane de-butane reboiler 6 are equipped with an automatic control system. The automatic control system adjusts the flow rate and heat exchange efficiency of each condensate according to the heat demand of the butane de-butane and ethane de-butane towers.

[0033] In one possible implementation, the seventh pipe 61 is fixedly connected to the ninth pipe 63 via the tenth pipe 64. The connection point between the tenth pipe 64 and the seventh pipe 61 is located below the fifth valve, and the connection point between the tenth pipe 64 and the ninth pipe 63 is located below the sixth valve. The seventh valve is installed on the tenth pipe 64. When excess medium-pressure condensate in the medium-pressure condensate tank 4 is no longer needed, the seventh valve is opened and the fifth valve is closed. The medium-pressure condensate in the medium-pressure condensate tank 4 then flows through the sixth pipe 41, the tenth pipe 64, and the ninth pipe 63 into the condensate collection bag 9 for storage.

[0034] As one possible implementation, a second deethaner reboiler 7 is also included. The inlet of the second deethaner reboiler 7 is used to introduce steam, and the outlet of the second deethaner reboiler 7 is fixedly connected to the eighth pipe 62 via the eleventh pipe 71. The second deethaner reboiler 7 is a standby unit and adopts a steam heating mode to ensure the normal operation of the deethaner when the supply of medium-pressure condensate is insufficient.

[0035] Low-pressure steam is introduced into the reboiler 7 of the second deethanizer. The low-pressure steam exchanges heat counter-currently with the material entering the reboiler 7. The material after heat exchange enters the deethanizer through the eleventh pipe 71 and the eighth pipe 62. The heat from the low-pressure steam is used for heating and separation of the material inside the deethanizer. The low-pressure condensate after heat exchange is discharged through the condensate pipeline located at the outlet of the reboiler 7 of the second deethanizer.

[0036] In one possible implementation, the outlet of the condensate collection bag 9 is fixedly connected to the inlet of the second water pump 8, and the outlet of the second water pump 8 is fixedly connected to the circulating water heat exchanger 81. When the second water pump 8 starts, the low-pressure condensate in the condensate collection bag 9, after heat exchange, is discharged after heat exchange with the circulating water in the circulating water heat exchanger 81. It can then be further treated by wastewater treatment equipment, minimizing thermal pollution. The condensate collection bag 9 and the second water pump 8, and the second water pump 8 and the circulating water heat exchanger 81, are fixedly connected by a twelfth pipe.

[0037] In one possible implementation, the methanol-to-olefins unit includes a methanol superheater heat exchanger, which is fixedly connected to the inlet of a high-pressure condensate tank 1. The high-pressure condensate production rate is 7 tons / hour, with a temperature of 140°C and a pressure of 4.0 MPa. The methanol superheater heat exchanger produces high-pressure condensate, which is then stored in the high-pressure condensate tank 1.

[0038] In one possible implementation, the methanol-to-olefins unit includes an air cooler 42, which is fixedly connected to the inlet of a medium-pressure condensate tank 4. The medium-pressure condensate has a flow rate of 50 tons / hour, a temperature of 115°C, and a pressure of 1.0 MPa. A methanol preheating heat exchanger, a product water stripping tower reboiler, and an oxide stripping tower reboiler produce medium-pressure condensate. After heat exchange in the air cooler 42, the medium-pressure condensate enters the medium-pressure condensate tank 4 for storage. The air cooler 42 and the medium-pressure condensate tank 4 are fixedly connected via a thirteenth pipeline.

[0039] As one possible implementation, valves are also installed on the second pipe 22, the fifth pipe 31, the sixth pipe 41, the eighth pipe 62 and the eleventh pipe 71 to ensure the smooth transport of each condensate.

[0040] As one possible implementation, all of the above-mentioned pipelines are equipped with temperature sensors and pressure sensors to ensure that the flow rate and parameters of each condensate remain stable.

[0041] The embodiments described above are merely preferred embodiments of this utility model and are only used to explain this utility model. They are not intended to limit the scope of implementation of this utility model. For those skilled in the art, other implementation methods can be easily made by substitution or modification based on the technical content disclosed in this specification. Therefore, all changes and improvements made to the principles and process conditions of this utility model should be included within the scope of the patent application of this utility model.

Claims

1. A waste heat recovery device for a methanol-to-olefins plant, characterized in that, The system includes a high-pressure component, a low-pressure component, and a condensate collection bag (9). The high-pressure component includes a high-pressure condensate tank (1) and a first butane deboiler (2). The outlet of the high-pressure condensate tank (1) is fixedly connected to the inlet of the first butane deboiler (2). The outlet of the first butane deboiler (2) is fixedly connected to the inlet of the butane deboiler and the condensate collection bag (9). The low-pressure component includes a first water pump (5), a first ethane deboiler (6), and a medium-pressure condensate tank (4). The inlet of the first water pump (5) is fixedly connected to the outlet of the medium-pressure condensate tank (4). The outlet of the first water pump (5) is fixedly connected to the inlet of the first ethane deboiler (6). The outlet of the first ethane deboiler (6) is fixedly connected to the inlet of the ethane deboiler and the condensate collection bag (9).

2. The waste heat recovery equipment for a methanol-to-olefins plant according to claim 1, characterized in that, The inlet of the first butane de-butane tower reboiler (2) is fixedly connected to the outlet of the high-pressure condensate tank (1) through the first pipe (21). A first valve is provided on the first pipe (21). The outlet of the first butane de-butane tower reboiler (2) is fixedly connected to the inlet of the butane de-butane tower through the second pipe (22). The outlet of the first butane de-butane tower reboiler (2) is fixedly connected to the inlet of the condensate collection bag (9) through the third pipe (23). A third valve is provided on the third pipe (23).

3. The waste heat recovery equipment for a methanol-to-olefins plant according to claim 2, characterized in that, The first pipe (21) is fixedly connected to the third pipe (23) through the fourth pipe (24). The first pipe (21) is provided with a second valve, and the connection point between the fourth pipe (24) and the first pipe (21) is located between the first valve and the second valve. The connection point between the fourth pipe (24) and the third pipe (23) is located below the third valve. The fourth pipe (24) is provided with a fourth valve.

4. The waste heat recovery equipment for a methanol-to-olefins plant according to claim 2, characterized in that, It also includes a second butane reboiler (3), the inlet of which is used to introduce steam, and the outlet of which is fixedly connected to the second pipe (22) via a fifth pipe (31).

5. The waste heat recovery equipment for a methanol-to-olefins plant according to claim 1, characterized in that, The inlet of the first water pump (5) is fixedly connected to the outlet of the medium-pressure condensate tank (4) through the sixth pipe (41). The outlet of the first water pump (5) is fixedly connected to the inlet of the first deethaner reboiler (6) through the seventh pipe (61). A fifth valve is provided on the seventh pipe (61). The outlet of the first deethaner reboiler (6) is fixedly connected to the inlet of the deethaner through the eighth pipe (62). The outlet of the first deethaner reboiler (6) is fixedly connected to the inlet of the condensate collection bag (9) through the ninth pipe (63). A sixth valve is provided on the ninth pipe (63).

6. The waste heat recovery equipment for a methanol-to-olefins plant according to claim 5, characterized in that, The seventh pipe (61) is fixedly connected to the ninth pipe (63) through the tenth pipe (64). The connection point of the tenth pipe (64) and the seventh pipe (61) is located below the fifth valve. The connection point of the tenth pipe (64) and the ninth pipe (63) is located below the sixth valve. The seventh valve is provided on the tenth pipe (64).

7. The waste heat recovery equipment for a methanol-to-olefins unit according to claim 5, characterized in that, It also includes a second deethaner reboiler (7), the inlet of which is used to introduce steam, and the outlet of which is fixedly connected to the eighth pipe (62) through the eleventh pipe (71).

8. The waste heat recovery equipment for a methanol-to-olefins plant according to claim 1, characterized in that, The outlet of the condensate collection bag (9) is fixedly connected to the inlet of the second water pump (8), and the outlet of the second water pump (8) is fixedly connected to the circulating water heat exchanger (81).

9. The waste heat recovery equipment for a methanol-to-olefins plant according to claim 1, characterized in that, The methanol-to-olefins unit includes a methanol superheater heat exchanger, which is fixedly connected to the inlet of the high-pressure condensate tank (1).

10. The waste heat recovery equipment for a methanol-to-olefins plant according to claim 1, characterized in that, The methanol-to-olefins unit includes an air cooler (42), which is fixedly connected to the inlet of a medium-pressure condensate tank (4).

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