Energy-saving device for comprehensive utilization of heat energy of TDI rectification system
By introducing components such as an ODCB recovery tower, a steam condensate separation tank, and a falling film evaporator into the TDI distillation system, utilizing a condensate inlet pipe and heat exchange technology in combination with a heat pump unit, energy recycling is achieved in the TDI distillation process, solving the problem of high energy consumption in TDI production and reducing production costs.
Patent Information
- Application Number
- CN202422751782.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2025-09-16
- Estimated Expiration
- 2034-11-12
AI Technical Summary
The energy consumption of distillation operation in the TDI production process is high, resulting in high production costs.
An energy-saving device including the first ODCB recovery tower, the first steam condensate gas-liquid separation tank, the first steam condensate circulation pump and the falling film evaporator is adopted. The gas phase waste heat is reused through the condensate inlet pipe, reduced pressure flash evaporation and heat exchange, and the steam is reused in combination with the first-stage heat pump unit and the second-stage compressor.
The energy recycling in the TDI distillation process is realized, which reduces energy consumption and production costs.
Smart Images
Figure CN223336815U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of distillation and energy-saving equipment, and in particular relates to an energy-saving device for comprehensive utilization of heat energy of a TDI distillation system. Background Art
[0002] Distillation operations are widely used in production processes across various industries, including the petrochemical, chemical, and pharmaceutical sectors. Distillation equipment is used to distill mixtures, with distillation towers serving as the core of these operations. These towers utilize the varying volatilities of the components in a mixture to transfer light components (low-boiling substances) from the liquid phase to the vapor phase, while heavy components (high-boiling substances) from the vapor phase are transferred to the liquid phase, thereby separating the mixture and obtaining the separated products. Toluene diisocyanate (TDI) is a key raw material in the polyurethane industry. In TDI production, either a light solvent method (o-dichlorobenzene) or a heavy solvent method (diethyl toluenedicarboxylate) is often used as an inert solvent in the production reaction. Distillation technology is typically used to separate the TDI (toluene diisocyanate) solvent from the product. The first o-dichlorobenzene removal (ODCB) tower is a core component of this process. In the existing TDI distillation process, the separation of o-dichlorobenzene and TDI requires maintaining a relatively high temperature (138-155°C). Heating during the separation process consumes a large amount of energy, and cooling the separated product also consumes energy. The entire process has high energy consumption and high production costs. Utility Model Content
[0003] The purpose of the utility model is to provide an energy-saving device for comprehensive utilization of heat energy in a TDI distillation system, aiming to solve the problems of high energy consumption and high production cost in the distillation operation during the TDI production process.
[0004] To achieve the above-mentioned object, the technical solution adopted by the present invention is to provide an energy-saving device for comprehensive utilization of heat energy in a TDI distillation system, comprising: a first ODCB recovery tower, a first steam condensate gas-liquid separator, a first steam condensate circulation pump, and a falling film evaporator. The first steam condensate gas-liquid separator is provided with a condensate inlet pipe suitable for introducing condensate outside the boundary area. The first steam condensate gas-liquid separator is connected to the falling film evaporator via a pipeline. The first steam condensate circulation pump is disposed between the first steam condensate gas-liquid separator and the falling film evaporator. Steam condensate in the first steam condensate gas-liquid separator is discharged into the falling film evaporator after undergoing reduced pressure flash evaporation. The gas phase at the top of the first ODCB recovery tower enters the falling film evaporator and exchanges heat with the steam condensate in the falling film evaporator. After the heat exchange, the gas phase at the top of the first ODCB recovery tower is condensed and returned to the first ODCB recovery tower, and the steam condensate is returned to the first steam condensate gas-liquid separator.
[0005] In a possible implementation, a first tower reflux tank and a first tower reflux pump are provided on a pipeline for returning the gas phase condensed at the top of the first ODCB recovery tower in the falling film evaporator to the first ODCB recovery tower.
[0006] In a possible implementation, a first tower condenser is provided on the exhaust pipe of the falling film evaporator, and the gas phase in the falling film evaporator is discharged into the first tower condenser and returned to the first ODCB recovery tower after condensation.
[0007] In a possible implementation, the outlet of the first steam condensate circulation pump is further connected to a first-stage heat pump unit, and the steam condensate enters the first-stage heat pump unit to be pressurized to produce normal-pressure steam.
[0008] In a possible implementation, the outlet of the first-stage heat pump unit is connected to a second-stage compressor for pressurizing the atmospheric-pressure steam.
[0009] In a possible implementation, a high shear reactor and a reaction heater are further provided. The crude TDI produced in the high shear reactor is discharged into the reaction heater. The outlet of the secondary compressor is connected to the reaction heater.
[0010] In a possible implementation, a second steam-condensate gas-liquid separation tank is connected to the inlet of the first-stage heat pump unit.
[0011] In a possible implementation, the outlet of the second steam-condensate gas-liquid separation tank is connected to a steam-condensate pump.
[0012] In a possible implementation, the bottom of the first ODCB recovery tower is connected to a first tower circulation pump and a first tower reboiler, the outlet of the first tower reboiler is connected to the first ODCB recovery tower, and the first tower reboiler exchanges heat with the crude TDI in the first ODCB recovery tower.
[0013] In a possible implementation, the first tower reboiler is connected to a steam inlet pipeline.
[0014] The beneficial effects of the energy-saving device for comprehensive utilization of heat energy in a TDI distillation system provided by the utility model are:
[0015] Compared with the prior art, the invention comprises a first ODCB recovery tower, a first steam condensate gas-liquid separation tank, a first steam condensate circulation pump and a falling film evaporator. The first steam condensate gas-liquid separation tank is provided with a condensate inlet pipe. The condensate outside the boundary area enters the first steam condensate gas-liquid separation tank through the condensate inlet pipe. The condensate undergoes vacuum flash evaporation in the first steam condensate gas-liquid separation tank. The first steam condensate circulation pump drives the condensate into the falling film evaporator. The gas phase at the top of the first ODCB recovery tower enters the falling film evaporator. In the falling film evaporator, the gas phase of the first ODCB recovery tower exchanges heat with the condensate after the vacuum flash evaporation. After the heat exchange, the gas phase of the first ODCB recovery tower is condensed and returned to the first ODCB recovery tower. The steam condensate returns to the first steam condensate gas-liquid separation tank. The steam after the steam condensate is vaporized is discharged from the falling film evaporator, thereby realizing the reuse of the gas phase waste heat of the first ODCB recovery tower, saving energy and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0017] Figure 1 This is a schematic structural diagram of an energy-saving device for comprehensive utilization of thermal energy in a TDI distillation system provided by an embodiment of the present utility model.
[0018] In the figure: 1. First ODCB recovery tower; 2. First tower circulation pump; 3. First tower reboiler; 4. Falling film evaporator; 5. First tower condenser; 6. First tower reflux tank; 7. First tower reflux pump; 8. First steam condensate gas-liquid separator; 9. First steam condensate circulation pump; 10. First-stage heat pump unit; 11. Second-stage compressor; 12. Second steam condensate gas-liquid separator; 13. Steam condensate pump; 14. High shear reactor; 15. Reaction heater; 16. Condensate inlet pipe. DETAILED DESCRIPTION
[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0020] Please refer to Figure 1A specific embodiment of an energy-saving device for comprehensive utilization of heat energy in a TDI distillation system provided by the present invention will now be described. The device comprises a first ODCB recovery tower 1, a first steam condensate gas-liquid separator 8, a first steam condensate circulation pump 9, and a falling film evaporator 4. The first steam condensate gas-liquid separator 8 is provided with a condensate inlet pipe 16 for introducing condensate outside the boundary zone. The first steam condensate gas-liquid separator 8 is connected to the falling film evaporator 4 via a pipeline. The first steam condensate circulation pump 9 is disposed between the first steam condensate gas-liquid separator 8 and the falling film evaporator 4. Steam condensate in the first steam condensate gas-liquid separator 8 undergoes vacuum flash evaporation and is discharged into the falling film evaporator 4. The gas phase at the top of the first ODCB recovery tower 1 enters the falling film evaporator 4 and exchanges heat with the steam condensate in the falling film evaporator 4. After the heat exchange, the gas phase at the top of the first ODCB recovery tower 1 is condensed and returned to the first ODCB recovery tower 1, and the steam condensate is returned to the first steam condensate gas-liquid separator 8.
[0021] The utility model provides an energy-saving device for comprehensive utilization of heat energy of a TDI distillation system. Compared with the prior art, the utility model is provided with a first ODCB recovery tower 1, a first steam condensate gas-liquid separation tank 8, a first steam condensate circulation pump 9 and a falling film evaporator 4. The first steam condensate gas-liquid separation tank 8 is provided with a condensate inlet pipe 16. The condensate outside the boundary area enters the first steam condensate gas-liquid separation tank 8 through the condensate inlet pipe 16. The condensate undergoes reduced pressure flash evaporation in the first steam condensate gas-liquid separation tank 8. The first steam condensate circulation pump 9 drives the condensate to The gas phase at the top of the first ODCB recovery tower 1 enters the falling film evaporator 4. In the falling film evaporator 4, the gas phase of the first ODCB recovery tower 1 is heat exchanged with the condensate after the reduced pressure flash evaporation. After the heat exchange, the gas phase of the first ODCB recovery tower 1 is condensed and returned to the first ODCB recovery tower 1. The steam condensate is returned to the first steam condensate gas-liquid separation tank 8. The steam after the steam condensate is vaporized is discharged from the falling film evaporator 4, thereby realizing the reuse of the gas phase waste heat of the first ODCB recovery tower 1, saving energy and reducing costs.
[0022] For details, please refer to Figure 1, comprising a first ODCB recovery tower 1, a first steam condensate gas-liquid separation tank 8, a first steam condensate circulation pump 9 and a falling film evaporator 4, the condensate inlet pipe 16 is arranged on the side wall of the first steam condensate gas-liquid separation tank 8, the lower end of the first steam condensate gas-liquid separation tank 8 is connected to the liquid inlet of the upper end of the falling film evaporator 4 through a pipeline, the first steam condensate circulation pump 9 is arranged between the first steam condensate gas-liquid separation tank 8 and the falling film evaporator 4, the top of the first ODCB recovery tower 1 is connected to the upper end of the side wall of the falling film evaporator 4 The upper air inlet of the first ODCB recovery tower 1 is connected by a pipeline to facilitate the discharge of the gas phase of the first ODCB recovery tower 1. The upper part of the side wall of the first ODCB recovery tower 1 is connected to the lower air outlet of the side wall of the falling film evaporator 4 by a pipeline to facilitate the return of the gas phase of the first ODCB recovery tower 1 to the first ODCB recovery tower 1 after condensation. The lower part of the side wall of the falling film evaporator 4 is provided with an exhaust pipe for facilitating the discharge of steam. The bottom of the falling film evaporator 4 is connected to the side wall of the first steam condensate gas-liquid separation tank 8 by a pipeline to facilitate the return of condensate to the falling film evaporator 4.
[0023] As a specific embodiment of the energy-saving device for comprehensive utilization of heat energy of a TDI distillation system provided by the present invention, please refer to Figure 1 The pipeline for returning the gas phase condensed from the top of the first ODCB recovery tower 1 in the falling film evaporator 4 to the first ODCB recovery tower 1 is provided with a first tower reflux tank 6 and a first tower reflux pump 7 .
[0024] For details, please refer to Figure 1 The first tower reflux tank 6 and the first tower reflux pump 7 are arranged on the pipeline for returning the gas phase condensation of the falling film evaporator 4 to the first ODCB recovery tower 1. The first tower reflux pump 7 is arranged between the first tower reflux tank 6 and the first ODCB recovery tower 1 to facilitate reflux. The liquid phase material flowing back into the first ODCB recovery tower 1 is sprayed into the first ODCB recovery tower 1.
[0025] As a specific embodiment of the energy-saving device for comprehensive utilization of heat energy of a TDI distillation system provided by the present invention, please refer to Figure 1 A first tower condenser 5 is provided on the exhaust pipe of the falling film evaporator 4 , and the gas phase in the falling film evaporator 4 is discharged into the first tower condenser 5 and returned to the first ODCB recovery tower 1 after condensation.
[0026] For details, please refer to Figure 1 The first tower condenser 5 is arranged on the exhaust pipe of the falling film evaporator 4. The first tower condenser 5 condenses the discharged gas phase. The liquefiable material is discharged into the first tower reflux tank 6 after liquefaction, and the non-liquefiable gas is directly discharged to facilitate the recovery of the material.
[0027] As a specific embodiment of the energy-saving device for comprehensive utilization of heat energy of a TDI distillation system provided by the present invention, please refer to Figure 1 The outlet of the first steam condensate circulation pump 9 is also connected to a first-stage heat pump unit 10, and the steam condensate enters the first-stage heat pump unit 10 and is pressurized to produce normal-pressure steam.
[0028] For details, please refer to Figure 1 The first-stage heat pump unit 10 is connected to the outlet of the first steam condensate circulation pump 9 through a pipeline. The first-stage heat pump unit 10 pressurizes the steam condensate to produce normal-pressure steam, which is reused to save energy.
[0029] As a specific embodiment of the energy-saving device for comprehensive utilization of heat energy of a TDI distillation system provided by the present invention, please refer to Figure 1 The outlet of the first-stage heat pump unit 10 is connected to a second-stage compressor 11 for pressurizing the normal-pressure steam.
[0030] For details, please refer to Figure 1 The secondary compressor 11 is arranged at the outlet of the primary heat pump unit 10 to pressurize the normal pressure steam. The pressurized steam discharged by the secondary compressor 11 can be used by users of each unit heat exchanger.
[0031] As a specific embodiment of the energy-saving device for comprehensive utilization of heat energy of a TDI distillation system provided by the present invention, please refer to Figure 1 A high shear reactor 14 and a reaction heater 15 are also provided. The crude TDI produced in the high shear reactor 14 is discharged into the reaction heater 15 , and the outlet of the secondary compressor 11 is connected to the reaction heater 15 .
[0032] For details, please refer to Figure 1 Phosgene and toluenediamine react in the high shear reactor 14 to generate crude TDI containing a large amount of intermediate products. The crude TDI is discharged into the reaction heater 15. The pressurized steam in the secondary compressor 11 enters the reaction heater 15. In the reaction heater 15, the crude TDI exchanges heat with the pressurized steam to promote decomposition. The generated crude TDI enters the subsequent process for further separation.
[0033] As a specific embodiment of the energy-saving device for comprehensive utilization of heat energy of a TDI distillation system provided by the present invention, please refer to Figure 1 The inlet of the first-stage heat pump unit 10 is connected to a second steam condensate gas-liquid separation tank 12.
[0034] For details, please refer to Figure 1The outlet of the first steam condensate circulation pump 9 is provided with a pipe connected to the side wall of the second steam condensate gas-liquid separation tank 12, which facilitates the steam condensate to enter the second steam condensate gas-liquid separation tank 12 and facilitates the adjustment of the liquid surface pressure in the device. The second steam condensate gas-liquid separation tank 12 is connected to the inlet of the first-stage heat pump unit 10 through a pipe. The condensate in front of the inlet of the first-stage heat pump unit 10 enters the second steam condensate gas-liquid separation tank 12, which facilitates the discharge of the condensate.
[0035] As a specific embodiment of the energy-saving device for comprehensive utilization of heat energy of a TDI distillation system provided by the present invention, please refer to Figure 1 The outlet of the second steam condensate gas-liquid separation tank 12 is connected to a steam condensate pump 13.
[0036] For details, please refer to Figure 1 The steam condensate pump 13 is arranged at the outlet of the second steam condensate gas-liquid separation tank 12, which facilitates the discharge of condensate in the second steam condensate gas-liquid separation tank 12. The front side of the inlet of the secondary compressor 11 is connected to the outlet pipe of the steam condensate pump 13 through a pipe, which facilitates the discharge of condensate on the front side of the inlet of the secondary compressor 11.
[0037] As a specific embodiment of the energy-saving device for comprehensive utilization of heat energy of a TDI distillation system provided by the present invention, please refer to Figure 1 The bottom of the first ODCB recovery tower 1 is connected to a first tower circulation pump 2 and a first tower reboiler 3. The outlet of the first tower reboiler 3 is connected to the first ODCB recovery tower 1. The first tower reboiler 3 exchanges heat with the crude TDI in the first ODCB recovery tower 1.
[0038] For details, please refer to Figure 1 The bottom of the first ODCB recovery tower 1 is connected to the first tower circulation pump 2 and the first tower reboiler 3 in sequence through pipelines. The outlet of the first tower reboiler 3 is connected to the first ODCB recovery tower 1. The crude TDI in the first ODCB recovery tower 1 enters the first tower reboiler 3 through the first tower circulation pump 2, and after heat exchange, returns to the first ODCB recovery tower 1. The crude TDI after heat exchange undergoes preliminary separation of ODCB and TDI in the tower.
[0039] For further information, please refer to Figure 1 , the crude TDI product can be discharged directly through the first tower circulation pump 2.
[0040] As a specific embodiment of the energy-saving device for comprehensive utilization of heat energy of a TDI distillation system provided by the present invention, please refer to Figure 1 The first tower reboiler 3 is connected to a steam inlet pipeline.
[0041] For details, please refer to Figure 1Atmospheric pressure steam is introduced into the first tower reboiler 3 for heat exchange. The first tower reboiler 3 is connected to the outlet of the secondary compressor (11) to facilitate the discharge of pressurized steam.
[0042] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. An energy-saving device for comprehensive utilization of heat energy in a TDI distillation system, characterized in that: The invention comprises a first ODCB recovery tower (1), a first steam condensate gas-liquid separation tank (8), a first steam condensate circulation pump (9) and a falling film evaporator (4); the first steam condensate gas-liquid separation tank (8) is provided with a condensate inlet pipe (16) suitable for introducing condensate outside the boundary area; the first steam condensate gas-liquid separation tank (8) is connected to the falling film evaporator (4) through a pipeline; the first steam condensate circulation pump (9) is provided between the first steam condensate gas-liquid separation tank (8) and the falling film evaporator (4); the steam condensate in the first steam condensate gas-liquid separation tank (8) undergoing reduced pressure flash evaporation is discharged into the falling film evaporator (4); the gas phase at the top of the first ODCB recovery tower (1) enters the falling film evaporator (4) and exchanges heat with the steam condensate in the falling film evaporator (4); after the heat exchange, the gas phase at the top of the first ODCB recovery tower (1) is condensed and returned to the first ODCB recovery tower (1); and the steam condensate returns to the first steam condensate gas-liquid separation tank (8).
2. The energy-saving device for comprehensive utilization of heat energy in a TDI distillation system according to claim 1, characterized in that: A first tower reflux tank (6) and a first tower reflux pump (7) are provided on a pipeline for returning the gas phase condensed at the top of the first ODCB recovery tower (1) in the falling film evaporator (4) to the first ODCB recovery tower (1).
3. The energy-saving device for comprehensive utilization of heat energy in a TDI distillation system according to claim 1, characterized in that: A first tower condenser (5) is provided on the exhaust pipe of the falling film evaporator (4), and the gas phase in the falling film evaporator (4) is discharged into the first tower condenser (5), and returns to the first ODCB recovery tower (1) after condensation.
4. The energy-saving device for comprehensive utilization of heat energy in a TDI distillation system according to claim 1, characterized in that: The outlet of the first steam condensate circulation pump (9) is also connected to a first-stage heat pump unit (10), and the steam condensate enters the first-stage heat pump unit (10) and is pressurized to produce normal-pressure steam.
5. The energy-saving device for comprehensive utilization of heat energy in a TDI distillation system according to claim 4, characterized in that: The outlet of the first-stage heat pump unit (10) is connected to a second-stage compressor (11) for pressurizing the normal-pressure steam.
6. The energy-saving device for comprehensive utilization of heat energy in a TDI distillation system according to claim 5, characterized in that: A high shear reactor (14) and a reaction heater (15) are also provided. The crude TDI produced in the high shear reactor (14) is discharged into the reaction heater (15). The outlet of the secondary compressor (11) is connected to the reaction heater (15).
7. The energy-saving device for comprehensive utilization of heat energy in a TDI distillation system according to claim 4, characterized in that: The inlet of the first-stage heat pump unit (10) is connected to a second steam-condensate gas-liquid separation tank (12).
8. The energy-saving device for comprehensive utilization of heat energy in a TDI distillation system according to claim 7, characterized in that: The outlet of the second steam condensate gas-liquid separation tank (12) is connected to a steam condensate pump (13).
9. The energy-saving device for comprehensive utilization of heat energy in a TDI distillation system according to claim 1, characterized in that: The bottom of the first ODCB recovery tower (1) is connected to a first tower circulation pump (2) and a first tower reboiler (3); the outlet of the first tower reboiler (3) is connected to the first ODCB recovery tower (1); and the first tower reboiler (3) performs heat exchange on the crude TDI in the first ODCB recovery tower (1).
10. The energy-saving device for comprehensive utilization of heat energy in a TDI distillation system according to claim 9, characterized in that: The first tower reboiler (3) is connected to a steam inlet pipeline.