Low-position steam upgrading utilization coupling device

Abstract

The utility model provides a low-level steam upgrading utilization coupling device, which belongs to the technical field of chemical heat energy recycling, and is structurally characterized in that a low-pressure steam pipeline forms steam source upgrading utilization of a high-pressure steam saturator (3); the medium-pressure steam flash tank (4) and the medium-pressure decomposition heater upper section (5) form a high-pressure heat source recycling system of the high-pressure steam saturator (3) and the stripping tower (6); the low-pressure steam pocket (7) and the total condensation reactor (8) form a medium-pressure heat source recycling system of the medium-pressure steam flash tank (4) and the medium-pressure decomposition heater upper section (5); and the medium-pressure heater (9), the low-pressure heater (10), the first-section evaporation heater (11) and the second-section evaporation heater (12) form a low-pressure heat source recycling system. The device is especially suitable for recycling steam heat energy of a coal water slurry gasification synthesis ammonia process and a steam stripping urea process. According to the utility model, the purpose of recycling heat energy is achieved by utilizing low-pressure steam in an upgrading manner.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical heat energy recovery and utilization, in particular to a low-level steam upgrading and utilization coupling device. Background Art

[0002] Steam network configuration is a crucial component of general chemical equipment systems, particularly in coal chemical projects. This approach requires consideration of various factors, including varying production processes, equipment requirements, and energy conservation and consumption reduction objectives. Steam networks are typically divided into different levels based on varying pressure and temperature requirements to facilitate more efficient energy utilization and meet diverse production conditions.

[0003] Currently, the coal-water slurry gasification ammonia synthesis process is typically configured with pipelines at five pressure levels: 9.8 MPa, 3.8 MPa, 2.5 MPa, 1.5 MPa, and 0.5 MPa. The urea steam used in the stripping process is typically controlled at a pressure of 1.6-1.9 MPa by the high-pressure steam saturator. Therefore, the urea section typically uses 2.5 MPa steam as a heat source, reducing the pressure to 1.6-1.9 MPa for use, resulting in some pressure waste. The urea unit also produces some low-pressure steam at 0.35 MPa as a byproduct. The original process could not effectively recover the steam due to the low pressure, and most of it was vented. With growing awareness of energy conservation, some units are adopting low-pressure deoxygenation, gas injection, and multi-effect evaporation and crystallization. However, these methods suffer from low efficiency, severe water carryover over long conveying distances, impacting turbine operation, and poor heat exchange. Summary of the Invention

[0004] The technical task of the utility model is to solve the deficiencies of the prior art and provide a low-level steam upgrading and utilization coupling device.

[0005] The technical solution of the present invention is realized in the following manner: the present invention is a low-pressure steam step-up utilization coupling device, characterized in that it includes a low-pressure steam pipeline, a high-pressure steam saturator (3), and a stripping tower (6);

[0006] The low-pressure steam pipeline is connected to the high-pressure steam saturator inlet pipe (40) and is connected to the high-pressure steam saturator (3), providing a steam source for the high-pressure steam saturator (3);

[0007] The top steam end of the high-pressure steam saturator (3) outputs upward and is connected to the stripping tower (6) to provide high-pressure saturated steam for the stripping tower (6);

[0008] The stripping tower condensate output pipe (17) at the lower section of the stripping tower (6) is refluxed and connected to the high-pressure steam saturator (3);

[0009] The side water vapor end of the high-pressure steam saturator (3) is output and connected to the medium-pressure steam flash tank (4), and the top steam end of the medium-pressure steam flash tank (4) is output to the medium-pressure steam flash tank outlet pipe (38);

[0010] The bottom of the medium-pressure steam flash tank (4) is connected to the upper section (5) of the medium-pressure decomposition heater through the medium-pressure decomposition heater inlet pipe (19).

[0011] The bottom section of the upper section (5) of the medium-pressure decomposition heater is connected to the top section of the low-pressure steam drum (7) through the low-pressure steam drum inlet pipe (20);

[0012] A low-pressure steam outlet pipe (21) is provided at the top of the low-pressure steam drum (7);

[0013] The medium-pressure steam flash tank outlet pipe (38) and the low-pressure steam outlet pipe (21) are connected to the 0.35MPa steam inlet pipe (25). The 0.35MPa steam inlet pipe (25) is divided into two paths: one path is downward through the 0.35MPa steam recovery pipe (26) and is recovered as a heat source;

[0014] The other one is connected to the steam compressor II (2), and the pressure is increased by the steam compressor II (2) and the steam outlet pipe (22) is output to the external pipe network at 0.5 MPa;

[0015] The low-pressure steam drum (7) and the top section of the full condensation reactor (8) are connected via the full condensation reactor outlet pipe (37); the low-pressure steam drum (7) and the bottom section of the full condensation reactor (8) are connected via the full condensation reactor inlet pipe (23);

[0016] A condensate outlet pipe I (24) output from the bottom end of the full condensation reactor (8);

[0017] The downstream of the 0.35MPa steam recovery pipe (26) is connected in parallel to the medium-pressure heater (9), the low-pressure heater (10), the first-stage evaporation heater (11), and the second-stage evaporation heater (12).

[0018] The low-pressure steam pipeline is composed of a 1.5MPa steam inlet pipe and a 2.5MPa steam inlet pipe, where:

[0019] The end section of the 1.5MPa steam inlet pipe is provided with a steam compressor I (1), which boosts the pressure and outputs the steam to the 1.8MPa steam outlet pipe and merges with the end section of the 2.5MPa steam inlet pipe;

[0020] An automatic regulating valve (41) is provided on the management of the 2.5MPa steam inlet pipe, and a pressure gauge (36) is provided on the high-pressure steam saturator (3). The pressure gauge (36) is electrically connected to and controls the opening of the automatic regulating valve (41).

[0021] The low-pressure steam pipeline constitutes a steam source for the high-pressure steam saturator (3) for upgrading and utilization.

[0022] The downstream of the 0.35MPa steam recovery pipe (26) is connected in parallel to the medium-pressure heater inlet pipe (27), the low-pressure heater inlet pipe (28), the first-stage evaporation heater inlet pipe (29), and the second-stage evaporation heater inlet pipe (30);

[0023] The medium-pressure heater inlet pipe (27) is connected to the medium-pressure heater (9) as a heat source, and the bottom end of the medium-pressure heater (9) is connected to the condensate outlet pipe II (31);

[0024] The low-pressure heater inlet pipe (28) is connected to the low-pressure heater (10) as a heat source, and the bottom end of the low-pressure heater (10) is connected to the condensate outlet pipe III (32);

[0025] A first section evaporation heater air inlet pipe (29) is connected to a first section evaporation heater (11) as a heat source, and a bottom end of the first section evaporation heater (11) is connected to a condensate outlet pipe IV (33);

[0026] The second-stage evaporation heater air inlet pipe (30) is connected to the second-stage evaporation heater (12) as a heat source, and the bottom end of the second-stage evaporation heater (12) is connected to the condensate outlet pipe V (34);

[0027] The condensate outlet pipe I (24), the condensate outlet pipe II (31), the condensate outlet pipe III (32), the condensate outlet pipe IV (33), and the condensate outlet pipe V (34) are merged into the low-pressure steam flash tank inlet pipe (35), and the low-pressure steam flash tank inlet pipe (35) is connected to the steam condensate tank (13) for storage and recycling.

[0028] The medium-pressure heater (9), the low-pressure heater (10), the first-stage evaporation heater (11), and the second-stage evaporation heater (12) constitute a low-pressure heat source recovery and utilization system.

[0029] The condensate outlet pipe I (24), the condensate outlet pipe II (31), the condensate outlet pipe III (32), the condensate outlet pipe IV (33), the condensate outlet pipe V (34), the low-pressure steam flash tank inlet pipe (35), and the steam condensate tank (13) constitute a final-stage heat source recovery and utilization system.

[0030] The low-pressure steam drum (7) and the full condensation reactor (8) constitute a medium-pressure heat source recovery and utilization system of the medium-pressure steam flash tank (4) and the upper section of the medium-pressure decomposition heater (5).

[0031] The medium-pressure steam flash tank (4) and the upper section of the medium-pressure decomposition heater (5) constitute a high-pressure heat source recovery and utilization system of the high-pressure steam saturator (3) and the stripping tower (6).

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] The utility model relates to a low-level steam step-up and utilization coupling device, which forms a steam source step-up and utilization of a high-pressure steam saturator (3) through a low-pressure steam pipeline; forms a high-pressure heat source recovery and utilization system of a high-pressure steam saturator (3) and a stripping tower (6) by using a medium-pressure steam flash tank (4) and an upper section of a medium-pressure decomposition heater (5); forms a medium-pressure heat source recovery and utilization system of a medium-pressure steam flash tank (4) and an upper section of a medium-pressure decomposition heater (5) by using a low-pressure steam drum (7) and a full condensation reactor (8); forms a low-pressure heat source recovery and utilization system by using a medium-pressure heater (9), a low-pressure heater (10), a first-stage evaporation heater (11), and a second-stage evaporation heater (12); and forms a final-stage heat source recovery and utilization system by using a condensate outlet pipe I (24), a condensate outlet pipe II (31), a condensate outlet pipe III (32), a condensate outlet pipe IV (33), a condensate outlet pipe V (34), a low-pressure steam flash tank inlet pipe (35), and a steam condensate tank (13).

[0034] The utility model is particularly suitable for recycling steam heat energy in ammonia synthesis process by gasification of water-coal slurry and urea stripping process.

[0035] This utility model uses a steam compressor to pressurize the 1.5Mpa by-product steam from the synthetic ammonia section to 1.8Mpa and generate a certain degree of superheat, thereby meeting the production requirements of urea stripping, avoiding pressure loss, and effectively reducing urea steam consumption. At the same time, the steam compressor is used to pressurize the 0.35Mpa low-pressure steam by-product of the urea unit to 0.5Mpa and feed it into the pipeline network, allowing the low-level steam to be upgraded and utilized.

[0036] The steam from the 1.5MPa pipeline network is compressed to 1.8MPa by adding a steam compressor at the urea high-pressure steam saturator. The steam is then sent to the high-pressure steam saturator pressure control valve and the saturator temperature is controlled by frequency conversion speed regulation, thereby controlling the stripping tower temperature.

[0037] At the urea low-pressure drum, a steam compressor is used to increase the pressure of the by-product 0.35MPa low-pressure steam to 0.5Mpa steam and send it into the pipeline network to achieve the effect of upgraded utilization.

[0038] The characteristics of this utility model are:

[0039] (1) The 1.5MPa steam upgrade saves the use of 2.5MPa steam in the urea section.

[0040] (2) Electric energy is used to increase steam pressure and superheat the steam, which reduces the steam consumption of the system, indirectly reduces the operating load of the boiler, and saves coal consumption for boiler operation.

[0041] (3) The low-level thermal energy of 0.35MPa is effectively utilized, which increases the output of 0.5MPa steam and increases economic benefits.

[0042] The low-level steam step-up coupling device of the utility model has the advantages of reasonable design, simple structure, safety and reliability, convenient use and easy maintenance, and has good promotion and use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Attachment Figure 1 It is a structural diagram of the present utility model.

[0044] The symbols in the accompanying drawings represent:

[0045] 1. Steam compressor I; 2. Steam compressor II; 3. High-pressure steam saturator; 4. Medium-pressure steam flash tank; 5. Upper section of medium-pressure decomposition heater; 6. Stripping tower; 7. Low-pressure steam drum; 8. Full condensation reactor; 9. Medium-pressure heater; 10. Low-pressure heater; 11. First-stage evaporation heater; 12. Second-stage evaporation heater; 13. Steam condensate tank;

[0046] 14. 1.5MPa steam inlet pipe; 15. 1.8MPa steam outlet pipe;

[0047] 16. Stripping tower air inlet pipe; 17. Stripping tower condensate pipe; 18. Medium-pressure steam flash tank inlet pipe; 19. Medium-pressure decomposition heater inlet pipe; 20. Low-pressure steam drum inlet pipe; 21. Low-pressure steam outlet pipe; 22. 0.5MPa steam outlet pipe; 23. Full condensation reactor inlet pipe;

[0048] 24. Condensate outlet pipe I;

[0049] 25. 0.35MPa steam inlet pipe;

[0050] 26. 0.35MPa steam recovery pipe;

[0051] 27. Medium-pressure heater inlet pipe; 28. Low-pressure heater inlet pipe; 29. ​​First-stage evaporator heater inlet pipe; 30. Second-stage evaporator heater inlet pipe;

[0052] 31. Condensate outlet pipe II; 32. Condensate outlet pipe III; 33. Condensate outlet pipe IV; 34. Condensate outlet pipe V; 35. Low-pressure steam flash tank inlet pipe;

[0053] 36. Pressure gauge; 37. Total condensation reactor outlet pipe; 38. Medium-pressure steam flash tank outlet pipe; 39. 2.5MPa steam inlet pipe; 40. High-pressure steam saturator inlet pipe; 41. Automatic regulating valve. DETAILED DESCRIPTION

[0054] The following is a detailed description of a low-level steam upgrading and utilization coupling device of the present invention in conjunction with the accompanying drawings.

[0055] As shown in the accompanying drawings, the utility model is a low-level steam upgrading and utilization coupling device, whose structure includes: steam compressor I, steam compressor II, high-pressure steam saturator, medium-pressure steam flash tank, medium-pressure decomposition heater, stripping tower, low-pressure steam drum, full condensation reactor, medium-pressure heater, low-pressure heater, first-stage evaporation heater, second-stage evaporation heater, and low-pressure steam flash tank.

[0056] The inlet of steam compressor I1 is connected to a 1.5 MPa steam inlet pipe 14, and the outlet is connected to a 1.8 MPa steam outlet pipe 15. 1.5 MPa steam originates from the steam network and enters steam compressor I1 through 1.5 MPa steam inlet pipe 14. The steam compressor then increases the pressure to 1.8 MPa before outputting it through 1.8 MPa steam outlet pipe 15.

[0057] The inlet of steam compressor II2 is connected to the 0.35 MPa steam inlet pipe 25, and the outlet is connected to the 0.5 MPa steam outlet pipe 22. Low-pressure steam, a byproduct of the low-pressure steam drum 7 and the medium-pressure steam flash tank, enters steam compressor II2 through the 0.35 MPa steam inlet pipe 25. The steam compressor increases the pressure to 0.5 MPa and then delivers it to the 0.5 MPa steam network through the 0.5 MPa steam outlet pipe 22.

[0058] The inlet of the high-pressure steam saturator 3 is connected to the high-pressure steam saturator inlet pipe 40 and the stripping tower condensate tank 17, while the outlet is connected to the stripping tower inlet pipe 16 and the medium-pressure steam flash tank inlet pipe 18. Steam from the 2.5MPa steam network is fed into the urea system via the 2.5MPa steam inlet pipe. It is then reduced in pressure to 1.8MPa by an automatic regulating valve 41 and transported to the high-pressure steam saturator 3 via the high-pressure steam saturator inlet pipe 40. The 1.5MPa steam is then increased in pressure to 1.8MPa by a steam compressor and connected to the high-pressure steam saturator inlet pipe 40 via the 1.8MPa steam outlet pipe. The two 1.8MPa steam streams are then combined and transported to the high-pressure steam saturator 3 via the high-pressure steam saturator inlet pipe 40. In the high-pressure steam saturator 3, the 1.8 MPa superheated steam is converted into saturated steam and transported to the stripping tower 6 through the stripping tower air inlet pipe 16 for use as a heat source; the high-temperature condensate enters the medium-pressure steam flash tank 4 through the medium-pressure steam flash tank inlet pipe 18 to form flash steam.

[0059] The inlet of the stripping tower 6 is connected to the stripping tower air inlet pipe 16, and the outlet is connected to the stripping tower condensate tank 17. The stripping tower's function is to separate free ammonia and methylammonium from the urea solution. Because the evaporation of free ammonia and the decomposition of methylammonium in the urea solution both require heat, 1.8 MPa saturated steam enters the stripping tower 6 through the stripping tower air inlet pipe 16, providing a heat source for the operation of the stripping tower 6. This ensures that the evaporation of free ammonia and the decomposition of methylammonium in the urea solution proceed in the forward direction, thereby improving stripping efficiency. After releasing heat, the steam turns into condensate, which then passes through the stripping tower condensate tank 17 and enters the high-pressure steam saturator 3 for recycling.

[0060] The inlet of the medium-pressure steam flash tank 4 is connected to the medium-pressure steam flash tank inlet pipe 18, and the outlet is connected to the medium-pressure decomposition heater inlet pipe 19 and the medium-pressure steam flash tank outlet pipe 38. High-temperature condensate from the high-pressure steam saturator 3 enters the medium-pressure steam flash tank 4 through the medium-pressure steam flash tank inlet pipe 18. Low-pressure steam is produced as a by-product through pressure reduction and flash evaporation. This by-product is then merged into the low-pressure steam outlet pipe 21 through the medium-pressure steam flash tank outlet pipe 38. The flashed condensate then enters the upper section of the medium-pressure decomposition heater upper section 5 through the medium-pressure decomposition heater inlet pipe 19 for use as a heat source.

[0061] The inlet end of the medium-pressure decomposition heater upper section 5 is connected to the medium-pressure decomposition heater inlet pipe 19, and the outlet end is connected to the low-pressure steam drum inlet pipe 20. Condensate from the medium-pressure steam flash tank 4 enters the medium-pressure decomposition heater upper section through the medium-pressure decomposition heater inlet pipe 19, is used as a heat source for heat energy recovery, and then enters the low-pressure steam drum 7 through the low-pressure steam drum inlet pipe 20 to produce low-pressure steam as a by-product.

[0062] The inlet of the low-pressure steam drum 7 is connected to the low-pressure steam drum inlet pipe 20, and the outlet is connected to the low-pressure steam outlet pipe 21 and the total condensation reactor inlet pipe 23. Condensate from the upper section 5 of the medium-pressure decomposition heater enters the low-pressure steam drum 7 through the low-pressure steam drum inlet pipe 20. The 0.35 MPa low-pressure steam produced as a by-product in the low-pressure steam drum 7 is discharged through the low-pressure steam outlet pipe 21. The condensate enters the lower condensation section of the total condensation reactor through the total condensation reactor inlet pipe 23. Simultaneously, the low-pressure steam outlet pipe 21 splits into two paths. One portion is fed through the 0.35 MPa steam recovery pipe 26 to the medium-pressure decomposition heater, the low-pressure decomposition heater, the first-stage evaporation heater, and the second-stage evaporation heater for heat recovery. The excess steam not recovered by the system enters the steam compressor II 2 through the 0.35 MPa steam inlet pipe 25, where it is increased in pressure to 0.5 MPa and fed to the 0.5 MPa steam network.

[0063] The inlet of the total condensation reactor 8 is connected to the total condensation reactor inlet pipe 23, and the outlet is connected to the total condensation reactor outlet pipe 37. Condensate in the low-pressure steam drum 7 enters the lower condensation section of the total condensation reactor 8 through the total condensation reactor inlet pipe 23. The lower condensation section of the total condensation reactor is a vertical shell-and-tube heat exchanger. The material flows through the pipes, and the condensate flows through the pipes. The condensate absorbs heat from the material, condensing and cooling the material. Meanwhile, the by-product steam absorbed by the condensate is returned to the low-pressure steam drum 7 through the total condensation reactor outlet pipe 37 for recycling.

[0064] The inlet ends of the medium-pressure heater 9, the low-pressure heater 10, the first-stage evaporator heater 11, and the second-stage evaporator heater 12 are respectively connected to the medium-pressure heater air inlet pipe 27, the low-pressure heater air inlet pipe 28, the first-stage evaporator heater air inlet pipe 29, and the second-stage evaporator heater air inlet pipe 30, and the outlet ends are respectively connected to the condensate outlet pipe II 31, the condensate outlet pipe III 32, the condensate outlet pipe IV 33, and the condensate outlet pipe V 34. The 0.35MPa steam produced as a by-product of the device enters the medium-pressure heater 9, the low-pressure heater 10, the first-stage evaporator heater 11, and the second-stage evaporator heater 12 through the medium-pressure heater inlet pipe 27, the low-pressure heater inlet pipe 28, the first-stage evaporator heater inlet pipe 29, and the second-stage evaporator heater inlet pipe 30 for use as a heat source. The condensate is introduced into the low-pressure steam flash tank inlet pipe 35 through the condensate outlet pipe II 31, the condensate outlet pipe III 32, the condensate outlet pipe IV 33, and the condensate outlet pipe V 34, and is then collected and stored in the steam condensate tank 13 for recycling.

[0065] Furthermore, an automatic regulating valve 41 is installed on the 2.5MPa steam inlet pipe 39. If the 1.5MPa steam is insufficient to meet the usage of the urea section, the automatic regulating valve 41 can be used to reduce the pressure from 2.5MPa to 1.8MPa.

[0066] Furthermore, a pressure gauge 36 is installed on the high-pressure steam saturator 3. The pressure gauge is equipped with a remote transmission function to realize remote control of the DCS system. At the same time, an automatic regulation loop is set up between the pressure gauge 36 and the automatic regulating valve 41. The automatic regulating valve 41 can adjust the opening according to the value of the pressure gauge 36 to ensure the stability of the steam pressure.

Claims

1. A low-level steam upgrading and utilization coupling device, characterized in that It includes a low-pressure steam pipeline, a high-pressure steam saturator (3), and a stripping tower (6); The low-pressure steam pipeline is connected to the high-pressure steam saturator inlet pipe (40) and is connected to the high-pressure steam saturator (3), providing a steam source for the high-pressure steam saturator (3); The top steam end of the high-pressure steam saturator (3) outputs upward and is connected to the stripping tower (6) to provide high-pressure saturated steam for the stripping tower (6); The stripping tower condensate output pipe (17) at the lower section of the stripping tower (6) is refluxed and connected to the high-pressure steam saturator (3); The side water vapor end of the high-pressure steam saturator (3) is output and connected to the medium-pressure steam flash tank (4), and the top steam end of the medium-pressure steam flash tank (4) is output to the medium-pressure steam flash tank outlet pipe (38); The bottom of the medium-pressure steam flash tank (4) is connected to the upper section (5) of the medium-pressure decomposition heater through the medium-pressure decomposition heater inlet pipe (19). The bottom section of the upper section (5) of the medium-pressure decomposition heater is connected to the top section of the low-pressure steam drum (7) through the low-pressure steam drum inlet pipe (20); A low-pressure steam outlet pipe (21) is provided at the top of the low-pressure steam drum (7); The medium-pressure steam flash tank outlet pipe (38) and the low-pressure steam outlet pipe (21) are connected to the 0.35MPa steam inlet pipe (25). The 0.35MPa steam inlet pipe (25) is divided into two paths: one path is downward through the 0.35MPa steam recovery pipe (26) and is recovered as a heat source; The other one is connected to the steam compressor II (2), and the pressure is increased by the steam compressor II (2) and the steam outlet pipe (22) is output to the external pipe network at 0.5 MPa; The low-pressure steam drum (7) and the top section of the full condensation reactor (8) are connected via the full condensation reactor outlet pipe (37); the low-pressure steam drum (7) and the bottom section of the full condensation reactor (8) are connected via the full condensation reactor inlet pipe (23); A condensate outlet pipe I (24) output from the bottom end of the full condensation reactor (8); The downstream of the 0.35MPa steam recovery pipe (26) is connected in parallel to the medium-pressure heater (9), the low-pressure heater (10), the first-stage evaporation heater (11), and the second-stage evaporation heater (12).

2. The low-level steam upgrading and utilization coupling device according to claim 1, characterized in that: The low-pressure steam pipeline is composed of a 1.5MPa steam inlet pipe and a 2.5MPa steam inlet pipe, where: The end section of the 1.5MPa steam inlet pipe is provided with a steam compressor I (1), which boosts the pressure and outputs the steam to the 1.8MPa steam outlet pipe and merges with the end section of the 2.5MPa steam inlet pipe; An automatic regulating valve (41) is provided on the management of the 2.5MPa steam inlet pipe, and a pressure gauge (36) is provided on the high-pressure steam saturator (3). The pressure gauge (36) is electrically connected to and controls the opening of the automatic regulating valve (41).

3. The low-level steam upgrading and utilization coupling device according to claim 2, characterized in that: The low-pressure steam pipeline constitutes a steam source for the high-pressure steam saturator (3) for upgrading and utilization.

4. The low-level steam upgrading and utilization coupling device according to claim 1, characterized in that: The downstream of the 0.35MPa steam recovery pipe (26) is connected in parallel to the medium-pressure heater inlet pipe (27), the low-pressure heater inlet pipe (28), the first-stage evaporation heater inlet pipe (29), and the second-stage evaporation heater inlet pipe (30); The medium-pressure heater inlet pipe (27) is connected to the medium-pressure heater (9) as a heat source, and the bottom end of the medium-pressure heater (9) is connected to the condensate outlet pipe II (31); The low-pressure heater inlet pipe (28) is connected to the low-pressure heater (10) as a heat source, and the bottom end of the low-pressure heater (10) is connected to the condensate outlet pipe III (32); A first section evaporation heater air inlet pipe (29) is connected to a first section evaporation heater (11) as a heat source, and a bottom end of the first section evaporation heater (11) is connected to a condensate outlet pipe IV (33); The second-stage evaporation heater air inlet pipe (30) is connected to the second-stage evaporation heater (12) as a heat source, and the bottom end of the second-stage evaporation heater (12) is connected to the condensate outlet pipe V (34); The condensate outlet pipe I (24), the condensate outlet pipe II (31), the condensate outlet pipe III (32), the condensate outlet pipe IV (33), and the condensate outlet pipe V (34) are merged into the low-pressure steam flash tank inlet pipe (35), and the low-pressure steam flash tank inlet pipe (35) is connected to the steam condensate tank (13) for storage and recycling.

5. The low-level steam upgrading and utilization coupling device according to claim 1, characterized in that: The medium-pressure heater (9), the low-pressure heater (10), the first-stage evaporation heater (11), and the second-stage evaporation heater (12) constitute a low-pressure heat source recovery and utilization system.

6. The low-level steam upgrading and utilization coupling device according to claim 4, characterized in that: The condensate outlet pipe I (24), the condensate outlet pipe II (31), the condensate outlet pipe III (32), the condensate outlet pipe IV (33), the condensate outlet pipe V (34), the low-pressure steam flash tank inlet pipe (35), and the steam condensate tank (13) constitute a final-stage heat source recovery and utilization system.

7. The low-level steam upgrading and utilization coupling device according to claim 1, characterized in that: The low-pressure steam drum (7) and the full condensation reactor (8) constitute a medium-pressure heat source recovery and utilization system of the medium-pressure steam flash tank (4) and the upper section of the medium-pressure decomposition heater (5).

8. The low-level steam upgrading and utilization coupling device according to claim 1, characterized in that: The medium-pressure steam flash tank (4) and the upper section of the medium-pressure decomposition heater (5) constitute a high-pressure heat source recovery and utilization system of the high-pressure steam saturator (3) and the stripping tower (6).

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