An apparatus and method for treating toluene diisocyanate tar residue

Abstract

This invention belongs to the field of chemical recycling technology, specifically relating to an apparatus and method for treating toluene diisocyanate tar residue. This invention combines a pre-fractionation tower, a solvent dehydration tower, and a solvent refining tower into a single complex tower (partition wall tower), thereby optimizing the process flow and improving energy efficiency. It also features thermal coupling and equipment integration, achieving a high degree of coupling between matter and energy during the separation process, saving on equipment investment and energy.

Description

Technical Field

[0001] This invention belongs to the field of chemical recycling technology, specifically relating to an apparatus and method for treating toluene diisocyanate tar residue. Background Technology

[0002] Toluene diisocyanate (TDI) is a common polyisocyanate and an important raw material for the production of polyurethane. Besides the production of polyurethane flexible foam for furniture, mattresses, cushions, and automotive seats, it is also used in the production of coatings, adhesives, sealants, specialty foams, and other products. TDI production is characterized by high investment, high technical difficulty, and challenging actual operation. Regardless of the production process, tar residue is always generated during TDI production. The tar residue mainly consists of polyisocyanates, which have certain resource utilization value and socio-economic and environmental benefits. Currently, the main methods for producing TDI domestically and internationally are the non-phosgene method and the phosgene method. The phosgene method uses highly toxic phosgene and toluene diamine as raw materials. The production process is complex, requires large equipment investment, has stringent production requirements, and is highly dangerous. However, due to its mature technology and low cost, it is the preferred mainstream process for TDI manufacturers both domestically and internationally. TDI's chemical structure contains two isocyanate groups, exhibiting high reactivity. Most of its components can react with each other or undergo self-reaction. It readily reacts with substances containing active hydrogen, and many side reactions occur during preparation and purification. These byproducts continuously deposit in the tower, forming tar-like substances. The viscosity of these tars is too high, the reaction temperature is too high, and the retention time is too long, causing them to remain at the bottom of the tower and in the pipes.

[0003] Currently, industrial processes primarily treat TDI through incineration and landfill. Incineration generates large amounts of carbon dioxide, nitrogen oxides, and wastewater, polluting the environment. TDI tar residue has two main characteristics: firstly, its large output (10 tons of tar residue are generated for every 100 tons of TDI produced); and secondly, it causes severe pollution to the atmosphere and soil. More importantly, incineration wastes valuable TDA resources in the tar residue, increasing disposal costs and thus exacerbating the environmental pressure and cost burden on enterprises. TDA is a major raw material for TDI production and an intermediate in various pharmaceuticals and dyes. From the perspective of achieving a virtuous cycle in TDI production by recovering the residual TDA from TDI tar residue, waste resource utilization can be achieved, offering certain environmental benefits and economic advantages.

[0004] Existing technology involves placing tar residue, high-boiling-point solvent, catalyst, and water, recovered from distillation equipment, into a high-temperature, high-pressure reactor. The tar residue hydrolyzes to generate toluenediamine. The liquid phase from the reactor is directly fed to a pre-separation tower. Water vapor and solvent are collected from the top of the pre-separation tower and fed to a solvent dehydration tower. Water is collected from the top of the solvent dehydration tower, and solvent is collected from the bottom. The solvent, toluenediamine, and tar residue separated from the bottom of the pre-separation tower are fed to a solvent refining tower. Solvent is collected from the top of the solvent refining tower, and tar residue and toluenediamine are collected from the bottom and fed directly to a dryer. The dryer removes most of the tar residue, and the remaining residue, along with toluenediamine, is fed to a toluenediamine distillation tower. Toluenediamine is collected from the top of the toluenediamine distillation tower, and tar residue is collected from the bottom. Traditional distillation processes are characterized by high energy consumption, complex structure, low energy efficiency, and high equipment investment costs. Summary of the Invention

[0005] In view of this, the present invention provides an apparatus and method for treating toluene diisocyanate tar residue. The apparatus provided by the present invention has a simple structure, low energy consumption, and yields high-purity toluene diamine through resource utilization.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides an apparatus for treating toluene diisocyanate tar residue, comprising a reaction vessel 1, a partition tower 2, a dryer 7, and a distillation tower 8 connected in sequence; the partition tower 2 includes a pre-fractionation tower and a main tower connected in sequence.

[0007] Preferably, the tops of the pre-fractionation tower and the main tower are connected by a gas reflux pipe 3; the bottoms of the pre-fractionation tower and the main tower are connected by a liquid reflux pipe 4.

[0008] Preferably, the number of gas phase reflux pipes and liquid phase reflux pipes is 2; the main tower is equipped with a side-stream extraction.

[0009] Preferably, the device further includes a condenser 5 disposed at the top of the main tower; the condenser 5 is in cyclic communication with the top of the main tower.

[0010] Preferably, the device further includes a reboiler 6 disposed at the bottom of the main column; the reboiler 6 is in cyclic communication with the bottom of the main column.

[0011] This invention also provides a method for resource-based utilization of toluene diisocyanate tar residue using the aforementioned equipment, comprising the following steps: The material to be processed is transported to a reactor for hydrolysis to obtain hydrolyzed material. The hydrolysis reaction material is fed into a pre-fractionation tower for fractionation. Water vapor and part of the gaseous alcohol solvent are obtained at the top of the tower, and the remaining liquid alcohol solvent, toluene diamine and tar residue are obtained at the bottom of the tower. Water vapor and part of the gaseous alcohol solvent enter the top of the main column for condensation; the remaining liquid alcohol solvent, toluene diamine and tar residue enter the bottom of the main column for separation, water is collected from the top of the main column; alcohol solvent is collected from the side stream; the tar residue and toluene diamine in the bottom of the column are directly sent to the dryer for pyrolysis to remove most of the tar residue, and the remaining tar residue is obtained at the bottom of the dryer. The remaining tar residue and toluene diamine are fed into a distillation column for distillation. Toluene diamine is collected at the top of the distillation column, and tar residue is collected at the bottom.

[0012] Preferably, the mass fraction of water in the material to be treated is 25-32%, the mass fraction of alcohol solvent is 48-55%, the mass fraction of catalyst is 0.5-3%, and the mass fraction of tar residue is 13-27%.

[0013] Preferably, the hydrolysis reaction is carried out at a temperature of 170~195℃ and a pressure of 0.3~0.5MPa.

[0014] Preferably, the operating pressure of both the pre-fractionation tower and the main tower is 20~50 kPa.

[0015] Preferably, the pyrolysis temperature is 270~280℃ and the pressure is 10~30kPa; the operating pressure of the distillation column is 15~30kPa; the top temperature of the column is 170~190℃ and the bottom temperature of the column is 215~240℃.

[0016] This invention combines the existing pre-separation tower, solvent dehydration tower, and solvent purification tower into a single complex tower (partition wall tower), thereby optimizing the process flow and improving energy efficiency. It also features thermal coupling and equipment integration, achieving a high degree of coupling between matter and energy during the separation process, thus saving on equipment investment and energy. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0018] Figure 1 This is a schematic diagram of equipment used to treat toluene diisocyanate tar residue, where 1-reaction vessel, 2-partitioned tower, 3-gas phase reflux pipe, 4-liquid phase reflux pipe, 5-condenser, 6-reboiler, 7-dryer, and 8-distillation column. Detailed Implementation

[0019] The present invention provides an apparatus for treating toluene diisocyanate tar residue, comprising a reaction vessel 1, a partition tower 2, a dryer 7, and a distillation tower 8 connected in sequence; the partition tower 2 includes a pre-fractionation tower and a main tower connected in sequence.

[0020] In this invention, the reactor is used to hydrolyze tar residue; the pre-fractionation tower receives the material from the hydrolysis reaction in the reactor; the main tower receives water, alcohol solvent, toluene diamine, and tar residue produced by the pre-fractionation tower; the alcohol solvent includes one or more of ethylene glycol, diethylene glycol, 1,2-propanediol, and dipropylene glycol; the dryer is used to remove tar residue; and the distillation tower is used to recover toluene diamine.

[0021] In this invention, the main tower is provided with a side stream for extraction; the top of the pre-fractionation tower and the main tower are connected by a gas phase reflux pipe 3; the bottom of the pre-fractionation tower and the main tower are connected by a liquid phase reflux pipe 4; and there are two gas phase reflux pipes and two liquid phase reflux pipes.

[0022] In this invention, the device further includes a condenser 5 disposed at the top of the main tower; the condenser 5 is in continuous communication with the top of the main tower. In this invention, the device further includes a reboiler 6 disposed at the bottom of the main column; the reboiler 6 is in cyclic communication with the bottom of the main column.

[0023] This invention also provides a method for resource-based utilization of toluene diisocyanate tar residue using the equipment described in the above technical solution, comprising the following steps: The material to be processed is transported to a reactor for hydrolysis to obtain hydrolyzed material. The hydrolysis reaction material is fed into a pre-fractionation tower for fractionation. Water vapor and part of the gaseous alcohol solvent are obtained at the top of the tower, and the remaining liquid alcohol solvent, toluene diamine and tar residue are obtained at the bottom of the tower. Water vapor and part of the gaseous alcohol solvent enter the top of the main column for condensation; the remaining liquid alcohol solvent, toluene diamine and tar residue enter the bottom of the main column for separation, water is collected from the top of the main column; alcohol solvent is collected from the side stream; the tar residue and toluene diamine in the bottom of the column are directly sent to the dryer for pyrolysis to remove most of the tar residue, and the remaining tar residue is obtained at the bottom of the dryer. The remaining tar residue and toluene diamine are fed into a distillation column for distillation. Toluene diamine is collected at the top of the distillation column, and tar residue is collected at the bottom.

[0024] The present invention transports the material to be processed to a reaction vessel for hydrolysis reaction to obtain hydrolyzed reaction material.

[0025] In this invention, the material to be treated is obtained by recovering toluene diisocyanate-containing tar generated during the phosgene process of toluene diisocyanate production using a distillation apparatus. As one embodiment of this invention, the material to be treated includes tar residue, an alcohol solvent, a catalyst, and water; the alcohol solvent includes one or more of ethylene glycol, diethylene glycol, 1,2-propanediol, and dipropylene glycol. The catalyst includes one or more of sodium carbonate, potassium hydroxide, calcium carbonate, and sodium hydroxide.

[0026] In this invention, the mass fraction of water in the material to be treated can be 25-32%, specifically 29%; the mass fraction of alcohol solvent can be 48-55%, specifically 52.2%; the mass fraction of catalyst can be 0.5-3%, specifically 0.8%; and the mass fraction of tar residue can be 13-27%, specifically 18%.

[0027] In this invention, the temperature of the hydrolysis reaction can be 170~195℃, specifically 171℃, 172℃, 173℃, 174℃, 175℃, 176℃, 178℃, 179℃, 180℃, 181℃, 182℃, 183℃, 184℃, 185℃, 186℃, 187℃, 188℃, 189℃, 190℃, 191℃, 192℃, 193℃, 194℃ or 195℃; the pressure can be 0.3~0.5MPa, specifically 0.3MPa, 0.4MPa or 0.5MPa. In this invention, the operating pressure of both the pre-fractionation column and the main column can be 20~50 kPa, specifically 20 kPa, 30 kPa, 40 kPa, or 50 kPa; the pyrolysis temperature can be 270~280℃, specifically 270℃, 271℃, 272℃, 273℃, 274℃, 275℃, 276℃, 277℃, 278℃, 279℃, or 280℃, and the pressure can be 10~30 kPa, specifically 10 kPa; the operating pressure of the distillation column can be 15~30 kPa, specifically 16 kPa, 17 kPa, 18 kPa, 19 kPa, 20 kPa, 21 kPa, 22 kPa, 23 kPa, 24 kPa, 25 kPa, 26 kPa, 27 kPa, 28 kPa, 29 kPa, or 30 kPa. The distillation column temperature can be 170~190℃, specifically 171℃, 172℃, 173℃, 174℃, 175℃, 176℃, 178℃, 179℃, 180℃, 181℃, 182℃, 183℃, 184℃, 185℃, 186℃, 187℃, 188℃, 189℃, or 190℃; the reboiler temperature can be 215~2 40℃ can be specifically 215℃, 216℃, 217℃, 218℃, 219℃, 220℃, 221℃, 222℃, 223℃, 224℃, 225℃, 226℃, 227℃, 228℃, 229℃, 230℃, 231℃, 232℃, 233℃, 234℃, 235℃, 236℃, 237℃, 238℃, 239℃, or 240℃.

[0028] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0029] The untreated material in the examples is obtained by recovering toluene diisocyanate-containing tar generated during the toluene diisocyanate phosgene process through distillation equipment.

[0030] Example 1 A feedstock containing tar residue recovered from distillation equipment, ethylene glycol, catalyst, and water is fed into a reactor. The feed flow rate is 19,000 kg / h, the water mass fraction is 29%, the ethylene glycol mass fraction is 52.2%, the sodium hydroxide catalyst mass fraction is 0.8%, and the tar residue mass fraction is 18%. The reactor temperature is 172℃ and the operating pressure is 0.4 MPa. The tar residue undergoes a hydrolysis reaction in the reactor to produce toluene diamine. The liquid phase of the reactor is fed into a pre-fractionation tower. Water and ethylene glycol are collected from the top of the pre-fractionation tower and then directly fed into the top of the main tower. After ethylene glycol, toluene diamine, and tar residue are collected from the bottom of the pre-fractionation tower, they are directly fed into the bottom of the main tower. The operating pressure of both the pre-fractionation tower and the main tower is 30 kPa. The main tower is connected to the rectification section of the pre-fractionation tower through a vapor reflux pipeline and to the stripping section of the pre-fractionation tower through a liquid reflux pipeline. The main column produces 99.9% pure water from the top and 99.5% pure ethylene glycol from the side stream. Toluene diamine and tar residue are directly fed into a dryer at an operating temperature of 272℃ and an operating pressure of 10 kPa. The dryer's liquid phase discharge contains 15% toluene diamine by mass. The remaining tar residue and toluene diamine are fed into a distillation column at an operating pressure of 16 kPa, a top temperature of 171℃, and a bottom temperature of 217℃. The distillation column produces 99.5% pure toluene diamine from the top and tar residue from the bottom. The total energy consumption of this process is 6895.54 kW.

[0031] Example 2 A feedstock containing tar residue recovered from distillation equipment, diethylene glycol, catalyst, and water is fed into a reactor. The feed mass flow rate is 19,000 kg / h, the mass fraction of water is 29%, the mass fraction of diethylene glycol is 52.2%, the mass fraction of potassium hydroxide is 0.8%, and the mass fraction of tar residue is 18%. The reactor temperature is 172℃ and the operating pressure is 0.4 MPa. The tar residue undergoes a hydrolysis reaction in the reactor to produce toluene diamine. The liquid phase of the reactor is fed into a pre-fractionation tower. Water and diethylene glycol are collected from the top of the pre-fractionation tower and then directly fed into the top of the main tower. After diethylene glycol, toluene diamine, and tar residue are collected from the bottom of the pre-fractionation tower, they are directly fed into the bottom of the main tower. The operating pressure of both the pre-fractionation tower and the main tower is 30 kPa. The main tower is connected to the rectification section of the pre-fractionation tower via a vapor reflux pipeline and to the stripping section of the pre-fractionation tower via a liquid reflux pipeline. Water with a purity of 99.9% is collected from the top of the main tower, and diethylene glycol with a purity of 99.5% is collected from the side stream. Toluene diamine and tar residue are directly fed into the dryer. The dryer operates at a temperature of 272℃ and a pressure of 10 kPa. The liquid phase output from the dryer contains 15% toluene diamine. The remaining tar residue and toluene diamine are fed into the rectification tower. The rectification tower operates at a pressure of 20 kPa, a top temperature of 178℃, and a bottom temperature of 224℃. Toluene diamine with a purity of 99.5% is collected from the top of the distillation column, and tar residue is collected from the bottom of the column; the total energy consumption of this process is 7843.5kW.

[0032] Example 3 A feedstock containing tar residue recovered from distillation equipment, ethylene glycol, catalyst, and water is fed into a reactor. The feed mass flow rate is 19,000 kg / h, the water mass fraction is 29%, the ethylene glycol mass fraction is 52.2%, the sodium carbonate mass fraction is 0.8%, and the tar residue mass fraction is 18%. The reactor temperature is 175℃ and the operating pressure is 0.3 MPa. The tar residue undergoes a hydrolysis reaction in the reactor to produce toluene diamine. The liquid phase of the reactor is fed into a pre-fractionation tower. Water and ethylene glycol are collected from the top of the pre-fractionation tower and then directly fed into the top of the main tower. After ethylene glycol, toluenediamine, and tar residue are collected from the bottom of the pre-fractionation tower, they are directly fed into the bottom of the main tower. Both the pre-fractionation tower and the main tower operate at a pressure of 40 kPa. The main tower is connected to the rectification section of the pre-fractionation tower via a vapor reflux pipeline and to the stripping section via a liquid reflux pipeline. Water with a purity of 99.9% is collected from the top of the main tower, and ethylene glycol with a purity of 99.5% is collected from the side stream. Toluenediamine and tar residue are directly fed into a dryer. The dryer operates at a temperature of 272℃ and a pressure of 10 kPa. The liquid phase output from the dryer contains 15% toluenediamine. The remaining tar residue and toluenediamine are fed into a rectification tower, which operates at a pressure of 25 kPa, a top temperature of 183℃, and a bottom temperature of 231℃. Toluene diamine with a purity of 99.5% is collected from the top of the distillation column, and tar residue is collected from the bottom of the column; the total energy consumption of this process is 8942.97kW.

[0033] Example 4 A feedstock containing tar residue recovered from distillation equipment, 1,2-propanediol, catalyst, and water is fed into a reactor. The feed mass flow rate is 19,000 kg / h, the mass fraction of water is 29%, the mass fraction of 1,2-propanediol is 52.2%, the mass fraction of calcium carbonate is 0.8%, and the mass fraction of tar residue is 18%. The reactor temperature is 172℃ and the operating pressure is 0.4 MPa. The tar residue undergoes a hydrolysis reaction in the reactor to produce toluene diamine. The liquid phase of the reactor is fed into a pre-fractionation tower. Water and 1,2-propanediol are collected from the top of the pre-fractionation tower and then directly fed into the top of the main tower. The 1,2-propanediol, toluenediamine, and tar residue collected from the bottom of the pre-fractionation tower are directly fed into the bottom of the main tower. Both the pre-fractionation tower and the main tower operate at a pressure of 30 kPa. The main tower is connected to the rectification section of the pre-fractionation tower via a vapor reflux pipeline and to the stripping section via a liquid reflux pipeline. Water with a purity of 99.9% is collected from the top of the main tower, and 1,2-propanediol with a purity of 99.5% is collected from the side stream. Toluenediamine and tar residue are directly fed into a dryer. The dryer operates at a temperature of 272℃ and a pressure of 10 kPa. The liquid phase output from the dryer contains 15% toluenediamine. The remaining tar residue and toluenediamine are fed into a rectification tower, which operates at a pressure of 30 kPa, a top temperature of 188℃, and a bottom temperature of 237℃. Toluene diamine with a purity of 99.5% is collected from the top of the distillation column, and tar residue is collected from the bottom of the column; the total energy consumption of this process is 7225.41kW.

[0034] Example 5 A feedstock containing tar residue recovered from distillation equipment, dipropylene glycol, catalyst, and water is fed into a reactor. The feed flow rate is 19,000 kg / h, the water content is 29%, the dipropylene glycol content is 52.2%, the sodium hydroxide content is 0.8%, and the tar residue content is 18%. The reactor temperature is 172℃ and the operating pressure is 0.4 MPa. The tar residue undergoes hydrolysis in the reactor to produce toluene diamine. The liquid phase from the reactor is fed into a pre-fractionation tower. Water and dipropylene glycol are collected from the top of the pre-fractionation tower and then directly enter the top of the main tower. Dipropylene glycol, toluene diamine, and tar residue are collected from the bottom of the pre-fractionation tower and then directly enter the bottom of the main tower. The operating pressure of both the pre-fractionation tower and the main tower is 30 kPa. The main tower is connected to the rectification section of the pre-fractionation tower via a vapor reflux pipeline and to the stripping section of the pre-fractionation tower via a liquid reflux pipeline. The main column produces 99.9% pure water from the top and 99.5% pure dipropylene glycol from the side stream. Toluene diamine and tar residue are directly fed into a dryer, which operates at 272℃ and 10kPa. The dryer's liquid output contains 15% toluene diamine. The remaining tar residue and toluene diamine are fed into a distillation column, which operates at 16kPa, with a top temperature of 171℃ and a bottom temperature of 217℃. The distillation column produces 99.5% pure toluene diamine from the top and tar residue from the bottom. The total energy consumption of this process is 7634.26kW.

[0035] Comparative Example 1 A feedstock containing tar residue recovered from distillation equipment, ethylene glycol, catalyst, and water is fed into a reactor. The feed flow rate is 19,000 kg / h, the water content is 29%, the ethylene glycol content is 52.2%, the sodium hydroxide content is 0.8%, and the tar residue content is 18%. The reactor temperature is 172℃ and the operating pressure is 0.4 MPa. The tar residue undergoes a hydrolysis reaction in the reactor to produce toluene diamine. The liquid phase from the reactor is fed into a pre-separation tower at an operating pressure of 30 kPa. The vapor and ethylene glycol from the top of the pre-separation tower are sent to the ethylene glycol dehydration system. The process involves several steps: First, a dehydration tower produces 99.9% pure water from its top and 99.9% pure ethylene glycol from its bottom. Second, a pre-separation tower separates ethylene glycol, toluenediamine, and tar residue, which are then fed to a refining tower. The refining tower produces 99.9% pure ethylene glycol from its top and tar residue and toluenediamine from its bottom, which are directly fed to a dryer. The dryer operates at 270°C and 10 kPa, removing most of the tar residue. The remaining residue and toluenediamine are then fed to a distillation tower. The distillation tower operates at 16 kPa, with a top temperature of 171°C and a bottom temperature of 217°C. The distillation tower produces 99.5% pure toluenediamine from its top and tar residue from its bottom. The total energy consumption for this process is 9194.06 kW.

[0036] Comparative Example 2 A feedstock containing tar residue recovered from distillation equipment, diethylene glycol, catalyst, and water is fed into a reactor. The feed flow rate is 19,000 kg / h, the water content is 29%, the diethylene glycol content is 52.2%, the sodium hydroxide content is 0.8%, and the tar residue content is 18%. The reactor temperature is 172℃ and the operating pressure is 0.4 MPa. The tar residue undergoes a hydrolysis reaction in the reactor to produce toluene diamine. The liquid phase from the reactor is fed into a pre-separation tower at an operating pressure of 30 kPa. The vapor and diethylene glycol collected from the top of the pre-separation tower are sent to the diethylene glycol dehydration unit. The diethylene glycol dehydration tower produces 99.9% pure water from its top and 99.9% pure diethylene glycol from its bottom. The pre-separation tower's bottom, separating diethylene glycol, toluene diamine, and tar residue, is then fed to the diethylene glycol refining tower. The refining tower produces 99.9% pure diethylene glycol from its top and tar residue and toluene diamine from its bottom, which are directly fed to a dryer. The dryer operates at 270°C and 10 kPa, removing most of the tar residue. The remaining residue and toluene diamine are fed to a distillation tower, operating at 16 kPa, with a top temperature of 171°C and a bottom temperature of 217°C. The distillation tower produces 99.5% pure toluene diamine from its top and tar residue from its bottom. The total energy consumption of this process is 10458 kW.

[0037] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An apparatus for treating toluene diisocyanate tar residue, characterized in that, It includes a reactor (1), a partition wall tower (2), a dryer (7), and a distillation tower (8) connected in sequence. The partition tower (2) includes a pre-fractionation tower and a main tower connected together.

2. The device as described in claim 1, characterized in that, The tops of the pre-fractionation tower and the main tower are connected by a gas reflux pipe (3); the bottoms of the pre-fractionation tower and the main tower are connected by a liquid reflux pipe (4).

3. The device as described in claim 2, characterized in that, The number of gas phase reflux pipes (3) and liquid phase reflux pipes (4) is 2 each; the main tower is equipped with side-stream extraction.

4. The device as described in claim 1, characterized in that, The equipment also includes a condenser (5) installed at the top of the main tower; the condenser (5) is in a circulating connection with the top of the main tower.

5. The device as described in claim 1, characterized in that, The device also includes a reboiler (6) disposed at the bottom of the main tower; the reboiler (6) is in circulation with the bottom of the main tower.

6. A method for resource-based utilization of toluene diisocyanate tar residue using the equipment described in any one of claims 1 to 5, characterized in that, Includes the following steps: The material to be processed is transported to a reactor for hydrolysis to obtain hydrolyzed material. The hydrolysis reaction material is fed into a pre-fractionation tower for fractionation. Water vapor and part of the gaseous alcohol solvent are obtained at the top of the tower, and the remaining liquid alcohol solvent, toluene diamine and tar residue are obtained at the bottom of the tower. Water vapor and part of the gaseous alcohol solvent enter the top of the main column for condensation; the remaining liquid alcohol solvent, toluene diamine and tar residue enter the bottom of the main column for separation, water is collected from the top of the main column; alcohol solvent is collected from the side stream; the tar residue and toluene diamine in the bottom of the column are directly sent to the dryer for pyrolysis to remove most of the tar residue, and the remaining tar residue is obtained at the bottom of the dryer. The remaining tar residue and toluene diamine are fed into a distillation column for distillation. Toluene diamine is collected at the top of the distillation column, and tar residue is collected at the bottom.

7. The method as described in claim 6, characterized in that, The material to be treated contains 25-32% water by mass, 48-55% alcohol solvent by mass, 0.5-3% catalyst by mass, and 13-27% tar residue by mass.

8. The method as described in claim 6, characterized in that, The hydrolysis reaction is carried out at a temperature of 170~195℃ and a pressure of 0.3~0.5MPa.

9. The method as described in claim 6, characterized in that, The operating pressure of both the pre-fractionation tower and the main tower is 20~50 kPa.

10. The method as described in claim 6, characterized in that, The pyrolysis temperature is 270~280℃ and the pressure is 10~30kPa; the operating pressure of the distillation column is 15~30kPa, the top temperature is 170~190℃, and the bottom temperature is 215~240℃.

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